biochem winter exam 2

2 important solutes in the formation of aqueous humor are Na and HCO3 . Na+ is actively transported to posterior chamber by Na+/K+ ATPase in ciliary epithelia. Na+ transport is balanced with release of HCO - into posterior chamber, which is produced by carbonic anhydrase (CO + H O H+ + HCO -) in ciliary epithelia.

A number of solutes are transported from the ultrafiltrate in the stroma to the posterior chamber.

• >99% of all filtered glucose is returned to the blood stream, since PCT is unable to metabolize any of the reabsorbed glucose. • this is very beneficial between meals and while fasting, when the only source of glucose is glycogenolysis and/or gluconeogenesis. • Since kidney is reabsorbing and not using glucose, hypoglycemia is avoided. • The regulation of gluconeogenesis is more straight forward because of the absence of glycolysis in the same cells.

Advantages of Not Having Glycolysis in PCT

Because a limited number of enzymes are used for the metabolism of a large number of drugs, CYP enzymes have a flexible substrate specificity and many drugs often compete for the same enzyme (six of the ~50 CYP enzymes metabolize 90% of all known medications). CYP2E1 is known to be involved in metabolism of anesthetics, alcohol, and acetaminophen. Drug metabolism leads to four possible scenarios (using an active drug as an example). Scenario 1 (Fig. A) and 2 (Fig. 2): CYP2E1 is NOT elevated, ie. the person is not a habitual drinker.

Alcohol metabolism affects metabolism of other xenobiotics

Alcoholic fatty liver results from the consumption of ~80 g or more of ethanol (~6 beers or 7 oz of 80-proof liquor) per day. • Fat and protein accumulate in perivenous hepatocytes• Fatty liver develops because: (↑ production coupled with ↓ clearance of fat) • Fatty acid synthesis is increased. High NADH levels slow down the TCA cycle and increase cytosolic citrate levels which feed into fatty acid biosynthesis. (Ethanol also increases the expression of the genes necessary for fat synthesis) • Fatty acid β-oxidation is decreased. High NADH levels decrease β-oxidation.• VLDL export is diminished. Acetaldehyde forms adducts with tubulin impairing microtubule function and decreasing vesicular export traffic. • Fatty liver is reversible if alcohol consumption stops

Alcoholic Steatosis

acetaldehyde produced by all three enzymes (ADH, CYP2E1 and catalase) that catalyze the first step in ethanol oxidation Acetaldehyde is highly reactive, toxic intermediate that is hypothesized to play a role in the etiology of a hangover Acetaldehyde forms damaging adducts with proteins (such as tubulin, collagen, VLDLs, and even CYP2E1 itself) and DNA (associated with carcinogenesis). Aldehyde dehydrogenase (ALDH), catalyzes the conversion of acetaldehyde to acetic acid. It is the second and last step in ethanol metabolism.

Aldehyde dehydrogenase

mushroom responsible for amatoxin poisoning. It contains several toxins that inhibit RNA pol II, preventing mRNA production leading to necrosis of liver cells and kidney cells (to a lesser degree).

Amanita phalloides (death cap)

Endothelial cells of capillary walls: These are the cells that create the primary barrier using tight junction and selective transport.

BBB 1st Barrier

Basement membrane (collagen, fibronectin, laminin) produced by pericytes. Pericytes also support the formation of the BBB postnatally and regulate the tight junctions of the endothelial walls and vesicular transport. Research indicates that a decrease in the number of pericytes increases the permeability of the BBB.

BBB 2nd Barrier

Astroglial endfeet cover 90% of the abluminal vascular surface. This is known as the glia limitans. Pericytes are sandwiched between astrocytic endfeet and endothelial cells.

BBB 3rd Barrier

are transported by the monocarboxylate transporters (MCTs.)

BBB Ketone Bodies, lactate and other metabolites

are transported by selective transport systems; certain amino acids are very selectively restricted (e.g., those that can act as neurotransmitters)

BBB amino acids

1) Passive diffusion (e.g., "Flip-flop mechanisms), especially for short and medium chain FAs (<12 C) 2) Facilitated transport via specific transporters, including several FA transport proteins (FATP-1, FATP-4 and fatty acid translocase) Both mechanisms have been shown to operate in BBB endothelial cells Note: The brain can perform some synthesis of non-essential FA and FA recycling, but FA are NOT used for β-oxidation in the brain.

BBB fatty acid transport mechanisms

transport is limited, but includes the essential ω-3 and ω-6 fatty acids. The brain performs FA synthesis, and endogenous recycling, but uses FAs primarily for structure.

BBB fatty acids

The Blood Brain Barrier is incomplete in some areas (circumventricular organs.) This enables the sensing of toxins, fuel molecules, peptide hormones, etc., to mediate the brain's contribution to relevant physiology or behavior. It also allows the secretion of hormones or glycoproteins.

BBB incomplete

Mainly Glucose is via selective GLUT expression (passive transport.) Glucose can be transported into the brain even at very low blood glucose concentrations. The brain must always have glucose.

BBB monosaccharides

pineal gland, posterior pituitary, median eminence.

BBB secretory organs

Area Postrema (vomiting in response to chemicals. Toxins etc.); glucose sensing neurons in lateral, arcuate, and ventromedial hypothalamus; subfornical organ.

BBB sensory organs

(baby aspirin, ~81 mg daily) may also be prescribed long-term as a preventative, but aspirin is generally less effective by itself than in combination with other drugs.

Aspirin therapy alone

Patients desiring to lose weight should be encouraged to look at weight loss and weight maintenance as a lifelong endeavor. Fad diets may result in weight loss, but to keep the weight off, changes must be made for a lifetime. Make small changes, once it's a habit make another change

Avoid the term "diet" as it implies a short-term fix

The polyol pathway is a minor pathway in the lens, nerve and kidney. Blood glucose enters the cells via an insulin-independent glucose carrier. Normally, the polyol pathway (catalyzes conversion of glucose into sorbitol and then fructose, involves aldose reductase and sorbitol dehydrogenase) is a minor pathway because aldose reductase has a much higher Km (lower affinity) for glucose than hexokinase (200 mM vs. 0.001 mM). In diabetics, circulating concentration of glucose is high (∴ more glucose enters the cell, raising intracellular concentration of glucose. Hyperglycemia increases the production of sorbitol in the lens via aldose reductase, with three undesired consequences: (i) Sorbitol production consumes NADPH, which is necessary to regenerate reduced glutathione (GSH). Decreased levels of GSH induce intracellular oxidative stress, which damages lens, nerve, or kidney cells. This is considered the most likely mechanism of diabetic cataracts. (ii) Sorbitol is very slowly metabolized, and the sorbitol carrier is very slow, thus sorbitol accumulates in cells. Sorbitol, an osmotically active molecule, increases osmotic pressure, which may lead to osmotic tissue swelling, aggregation of lens crystallins, increased light scattering and thus diabetic cataracts. (iii) Elevated levels of NADH, which impairs the normal NAD+/NADH ratio.

Biochemical basis of diabetic cataracts

Theliverisorganizedintothousandsofhexagonal structures called liver lobules Eachcornerofalobulecontainsabranchofthehepatic portal vein, a branch of the hepatic artery and a branch of the bile duct in what is known as the portal triad Hepaticportalveinsupplies~70%oftheblood,whichis nutrient-rich and oxygen poor Hepaticarterydelivers~30%oftheblood,whichishighly oxygenated Intheclassicliverlobule,bloodfromthetriadmixesinthe sinusoids and flows to the center of the lobule where it exits via the central vein.

Blood enters the liver lobule from two sources but exits via a single venous system

commonly used for long-term MI therapy. Plavix plus aspirin is still used, but less commonly now as Plavix may be less effective than Brilinta at reducing platelet reactivity . Brilinta, like Plavix, blocks the ADP receptor, preventing platelet activation.

Brilinta plus aspirin

• An important function of the kidney is to buffer urine, thus facilitating acid excretion • Addition of ammonia to urine helps prevent urinary pH from dropping below pH 4.5.• Also, in the long-term fasting, the NH3 picks up protons from ketone body dissociation and is excreted in the urine as ammonium (NH4+), thereby decreasing the acid load in the body. • Normally the distal convoluted tubule (DCT) is primarily responsible for correcting acid-base balance. • In starvation and acidosis, the PCT plays the largest role in buffering urinary acid; however, the DCT still plays a role in correcting the final urinary pH.

Buffering Urinary Acid

P450 enzyme found in perivenous hepatocytes associated with SER and is induced (5- to 10-fold increase) in habitual drinkers (>2 oz alcohol/day) • Ethanol stabilizes CYP2E1 as well as increases its gene expression • CYP2E1 is low-affinity, high-capacity enzyme (Km = 8 - 10 mM)• Consumes energy (NADPH) rather than generating energy

CYP2E1

Diminished pharmacological effect of the drug when alcohol levels are low in the body. In an alcoholic individual, levels of CYP2E1 are elevated and when alcohol levels are low (e.g. after awakening in the morning and before resuming alcohol consumption) drug metabolism is rapid due to the increased levels of CYP2E1 and little competition from alcohol. For example, an alcoholic patient requires more anesthetic during surgery because the anesthetic is more rapidly metabolized than it would be in non-alcoholics (presumably, ethanol levels are low immediately prior to operation). When large amounts of alcohol and the drug are ingested at the same time, both alcohol and the drug will compete for the elevated CYP2E1 resulting in an exaggerated pharmacological effect of the drug (it's not inactivated as fast). Exaggerated pharmacological effect of the drug when ethanol and drug levels are both high.

CYP2E1 is elevated in individuals who are habitual drinkers.

Troponins form 3-subunit complexes (cTnI, cTnC, and cTnT) that regulate Ca2+-mediated contraction. cTnI and cTnT are specific for cardiac tissue and are not normally detectable in the circulation (cTnC is non-specific). Following an MI, cTn begins to leak into the serum, rising in 2-4 hours and peaking around 48 hours. Elevated levels can persist for 7-14 days, depending on subunit. Positive troponin levels are considered virtually diagnostic of cardiac injury and they are the preferred test for MI. Newer high-sensitivity versions of this test (hs-cTn) that measure cTn at levels 5-fold to 100-fold lower than previous tests have substantially improved the usefulness of this test in identifying early stage (acute) myocardial infarction and tracking progression.

Cardiac-Specific Troponins (cTn):

▪ Dopamine (DA) ▪ Norepinephrine (NE) ▪ Epinephrine (EPI)

Catecholamines include:

produced in Duodenum and jejunum in response to Dietary fatty acids and protein ↓ Gastric emptying↓ Appetite via vagus nerve & NTS satiety center

Cholecystokinin (CCK)

Release epinephrine (80%) and norepinephrine (20%) in response to stress. Stress can result in an acetylcholine signal to the chromaffin cells from sympathetic nerve termini Synthesis of catecholamines uses the same enzymes as seen in nerve terminals; conversion of cytoplasmic dopamine to norepinephrine occurs in chromaffin granules

Chromaffin cells of the adrenal medulla:

Allosteric activation of phophorylase b -> activates glycogenolysis Allosteric activation of PFK-1 -> activates glycolysis AMP degradation by deaminases produces NH3, helps buffer H+ increase AMP degradation produces adenosine which increases vasodilation AMPK activation • Insulin independent GLUT4 membrane translocation --> increase FA, O2, glucose transport • Increase NO production--> vasodilation increase • Inhibition of acetyl CoA carboxylase-2 (ACC-2) --> malonyl CoA decrease • Activate malonyl CoA decarboxylase (MCoADC) --> malonyl CoA decrease

Consequences of exercise induced AMP increase

Increase in total serum cholesterol levels correlates with an increased risk of death from CHD. However: The risk is much higher in people with preexisting CHD and long-term high cholesterol Note: Half of individuals who suffer heart attacks have normal cholesterol levels Cholesterol values between 200 and 239 mg/dL result in a borderline risk Cholesterol levels ≥240 mg/dL result in an increased risk of CHD

Correlation between serum cholesterol levels and risk for coronary heart disease (CHD)

CK is a dimeric enzyme composed of a combination of two subunits, M and B, either as homodimers or heterodimers. MB heterodimers are predominantly found in cardiac muscle, but are also found in lesser amounts in skeletal muscle. CK-MB is not normally found in circulation, but is elevated when any muscle (skeletal or cardiac) is injured. Because of the increased sensitivity of newer hscTn tests, many emergency rooms are now beginning to phase out the use of CK-MB testing.

Creatine Kinase Isoenzyme MB (CK-MB)

Diacylglycerol(DAG) and ceramide inhibit Phosphoinositol 3 kinase (PI3 kinase) in the insulin signaling pathway which, depending on the tissue, will lower GLUT4 translocation and decrease NO production. The insulin signaling pathway using MAP kinase is unaffected by DAG and ceramide but is, in fact, more active because of the higher levels of insulin present due to insulin resistance resulting in an increased production of endothelium-1 (ET-1) The lower levels of NO and increased levels of ET-1 lead to vasoconstriction and increased blood pressure

DAG and Ceramide Promote Insulin Resistance

DASH diet lowers BP by 11 points in people with HTN Half of the decrease is because DASH diet is high in fruits and vegetables (↑potassium) The remaining half of the drop in BP is due to eating fish and chicken rather than beef and pork, vegetable oils instead of butter, and more low-fat dairy. Findings suggest that the age-related rise in BP can be reversed or prevented by consuming a DASH diet coupled with a low-sodium diet Besides lower BP and weight, the DASH diet lowers the risk of cancer, heart disease (↓ cholesterol), stroke, kidney stones and diabetes.

DASH diet

smooth muscle cells proliferate collagen and extracellular matrix are deposited lipid debris accumulates

Development of fibrous plaque (atheroma)

For long endurance exercises, like a marathon, there is insufficient muscle glycogen stores to complete the run. Dietary glucose is required to supplement muscle glycogen.

Dietary glucose helps spare muscle glycogen

• When anaerobic conditions prevail, PCT is unable to generate ATP. • For example, in case of septic shock/infection: • decreased renal perfusion and lower oxygen levels, leading to decreased ATP production à can result in renal failure(recall that glycolysis is the only pathway outside of the mitochondria which can make ATP.)

Disadvantages of Not Having Glycolysis in PCT

Hypertensive patients 30-50% of people with HTN are NaCl sensitive Individuals with a family history of HTN, even if the individual is normotensive Older patients (>50 years of age) Lowering salt decreases risk of age-related HTN African-Americans (4-fold greater risk of HTN than Caucasians) Sodium retention is advantageous near the equator because a great deal of salt is lost due to perspiring (temperature regulation) Obese patients Diabetic patients with HTN or with renal injury

EffectofNaClonBPismorepronouncedinthefollowingpopulations

Anti-Coagulation: Direct inhibitor of factor Xa. Prothrombin is no longer activated to thrombin, blocking the propagation of the coagulation cascade. long term

Eliquis (apixaban) or rivaroxaban, edoxaban mechanism of action and of the drugs used to treat/prevent heart attack.

Exerciseisanimportantwaytoprevent,treatandcontrolofHTN(moderate intensity, aerobic, 30 min/d, 5-7 days/wk) ExerciselowersBPbothacutelyandfollowingchronicexercisetraining(4-9 mmHg SBP) Exercisetrainingisassociatedwithvasodilation: Reduced levels of plasma norepinephrine Reduced levels of plasma endothelin-1 Increased production of NO

Exercise and HTN

100X Even during exercise, muscle ATP levels only drop 10 to 20% because ATP is rapidly resynthesized

Exercising muscle produces ----- more ATP relative to resting muscle

Type I fibers are more often used in activities of daily life, e.g. walking, etc. Whereas type II fibers are used when walking upstairs or lifting heavy boxes and older people either consciously or subconsciously, are less likely to use type II fibers.

Explain why Clyde's type II fibers are preferentially lost in age-related sarcopenia. (Type II fibers are primarily used to break a fall and are therefore of particular importance in the geriatric community.)

HDL is involved in reverse transport of cholesterol out of macrophages, foam cells and other extrahepatic tissues. This is critical for controlling cholesterol accumulation in blood vessels , as cholesterol cannot be degraded.

Explain why an elevated level of serum HDL has an anti-atherogenic effect.

Early in the run, there is inadequate blood flow to type II muscle fibers Insufficient blood flow at the start of running is precisely the reason why Type II fibers are used.

Explain why dietary glucose before the race would not "spare glycogen" in type II fibers.

Depletion of ATP → reduced Na+-K+ ATPase activity, reduced Ca2+ pump activity: inability to maintainionhomeostasis→intracellularaccumulationofNa+and Ca2+→osmoticaction→ swelling and cell lysis, and Ca2+ -dependent activation of intracellular proteases

Explain why prolonged ischemia will lead to necrosis of cardiac tissue

Any weight-bearing exercise will increase bone-mineral density (this compensates for the strain muscle use exerts on bones.)

Explain why weight training would help minimize the risk of osteoporosis

CrP depletion (e.g. sprint) occurs between 4 - 30 sec. (depends on intensity) High concentrations of H . Lactate production increases [H+]; [H+] inhibits PFK1, glycogen phosphorylase, creatine kinase Eventual muscle glycogen depletion

Fatigue for Type II fibers

ciliary processes --> posterior chamber --> anterior chamber --> trabecular meshwork --> Schlemm's canal

Flow of aqueous humor

1 Ultrafiltration of plasma 2 Transport of Na+ from stroma to posterior chamber 3 Release of HCO3- from NPE (HCO3- produced by carbonic anhydrase) to posterior chamber 4 Movement of H2O to posterior chamber as a result of osmotic gradient

Formation of aqueous humor

De Vivo Disease, inability to transport sufficient amounts of glucose into the brain. Results in seizures, microcephaly, intellectual disability or developmental delay, motor or speech problems. Currently treated with a ketogenic diet, which supplies ketone bodies to supplement the energy needs of the brain.

GLUT1 deficiency

produced in stomach in response to Fasting ↑ Appetite by ↑ release of NPY & AgRP

Ghrelin"Hunger Hormone"

produced in Ileum & colon in response to Dietary fat and carbohydrate ↓ Gastric emptying↓ Appetite (↓ NPY & AgRP) ↑ Glucose-dependent insulin release

Glucagon-like peptide (GLP-1)

(i) Hexose monophosphate shunt (~65%, highest activity in the body) (ii) Anaerobic glycolysis (~30%) (iii) Complete oxidation to CO2 and H2O through TCA & ETC (~5%)

Glucose metabolism in the cornea

Lens obtains nutrients from and eliminates waste into aqueous humor (i) Anaerobic glycolysis (~85%) (ii) HMP shunt (~10%) (iii) Complete oxidation to CO2 and H2O through TCA & ETC (~5%, by cells located at the periphery of the lens)

Glucose metabolism in the lens

1. In presynaptic neurons, newly‐synthesized glutamate is packaged into vesicles, and eventually released into the synaptic cleft. 2. In the synaptic cleft, glutamate binds to its receptors on the postsynaptic membrane. To terminate this signal, glutamate is either: • taken up by surrounding astrocytes via excitatory amino acid transporters (EAATs)—Na+ dependent symporters • taken up and recycled by the presynaptic neuron, also via an EAAT (less uptake than astrocytes) 3. Glutamate taken up by astrocytes is then converted into glutamine by glutamine synthetase, an enzyme expressed in the brain only by astrocytes, consuming ammonium and ATP. 4. Glutamine, now neutralized as a signaling molecule, is transported out of the astrocyte to be taken up by the neuron (or transported out of the brain) via Na+ dependent symporters ("A" or "N"). 5. Neurons convert glutamine (inactive as a signaling molecule) back into glutamate (neurotransmitter). This reaction is catalyzed by glutaminase (also present in vascular endothelial cells). This enzyme does NOT require ATP. This movement and metabolism of glutamate across neurons and astroglia is also known as the glutamate‐glutamine cycle.

Glutamate-Glutamine Homeostasis

due to AMP increase 1. muscle contraction ATP-> ADP + Pi 2. Pi: substrate for glycogenolysis and glycolysis; allosteric activator of PFK-1 3. ADP activates AK 4. AMP: allosterically activates both phosphorylase b (glycogenolysis) and PFK-1 (glycolysis)

Glycogenolysis, glycolysis activation during exercise

Heritability ranges from 30 to 60% depending on the population Family history of HTN, increases one's risk for HTN Environmentalfactors-Lifestyle Migration studies show that as migrants adopt the diet and lifestyle of the host country, their BP changes so that it closely resembles that of the host country

HTN is a Multifactorial Condition

• Haptoglobin (Hp; 86,000 Da) is a plasma a2-globulin which binds to free hemoglobin (Hb; 68,000 Da) or myoglobin (Mb; 17,000 Da) in a one-to-one ratio. • By complexing with Hb and Mb, plasma haptoglobin prevents hemoglobin- or myoglobin-mediated nephrotoxicity and iron loss following intravascular hemolysis or acute muscle injury. • How?• The Hp-heme protein complex is large enough that it cannot be filtered at the glomerulus

Haptoglobin (Hp)

Hyperglycemia mediates an upregulation (↑ gene expression) of a heparanase associated with mesangial cells. • Podocytes can secrete pre-proheparanase. Then, through proteolytic cleavage process, heparanase is made: • Heparanase cleaves heparan sulfate glomerular endothelium and the glomerular basement membrane. • Heparan sulfate is the main constituents and organizers of the extracellular matrix.• This remodeling allows increased filtration rate for albumin (next page). • As more albumin is filtered, it exceeds the kidney's capacity for protein reabsorption, resulting in albuminuria.

Heparanase and Albuminuria

Like most drugs, ethanol is metabolized primarily in perivenous hepatocytes. • Alcohol dehydrogenase (ADH) • CYP2E1 • Catalase

Hepatic Alcohol Metabolism

Rhodopsin is the photoreceptor in rods. It is G-protein-coupled receptor to which 11-cis-retinal is bound. Transducin is a G-protein formed by three subunits, α, β, and γ. In the dark- adapted state, it binds GDP. cGMP-phosphodiesterase (PDE) is a target enzyme, composed of two catalytic subunits (α, β) and two inhibitory subunits (γ). It catalyzes the conversion of cGMP into 5'-GMP.

How can light produce a change in the cGMP concentration?

1 Rhodopsin activation (R*, aka metarhodopsin) by light 2 GDP/GTP exchange in transducin (T) due to rhodopsin binding-induced conformational change 3 α-subunit of transducin (Tα) activates PDE 4 PDE hydrolyzes cGMPto5'-GMP 5 cGMP decreases and cGMP-gated Na+ channel closes

How can light produce a change in the cGMP concentration? steps

Bloodpressureisaleadingcauseofstroke,myocardialinfarction,heartfailure, renal failure and cognitive impairment.

Hypertension (HTN) and the Risk of Disease

Since neural signaling causes a local increase in brain energy metabolism energy metabolism can be used to "map" neural signaling: • Positron emission tomography (PET) uses radiolabeled tracers to localize and measure glucose (e.g., 18F-fluorodeoxyglucose; FDG) and oxygen (15O) metabolism in various tissues in vivo. • Functional Magnetic Resonance Imaging (fMRI): uses blood oxygenation (blood oxygen level dependent contrast) and flow to measure metabolism in vivo.

In Vivo brain imaging

can be red, green or blue opsin, making human color vision "trichromatic". These three proteins are similar but different from each other and from rhodopsin.

In cone cells, the photoreceptor protein

• Intravascular—RBCs lyse in the circulation, releasing hemoglobin into the plasma.• Extravascular: RBCs are phagocytized by macrophages in the spleen and liver

Intravascular hemolysis-in circulation: if no Haptoglobin (Hp) is available

= competition for CYP2E1, leading to exaggerated pharmacological effects of the drug because it is metabolized more slowly.

Large amount of alcohol plus presence of the drug

1. Irregular blood flow / turbulent blood flow: • Branching arteries, hypertension, vasoconstriction (stress on vasculature, smoking) 2. Chronic low-grade inflammation: Smoking Increased ROS production through macrophages Hyperglycemia, protein glycation Some infections (immune-induced injury); active periodontal disease Obesity: pro-inflammatory cytokines, increased ROS 3. Elevated LDL: increases LDL oxidation and uptake by macrophages, which increases ROS production in phagolysosomes - initiates vicious cycle of oxidation

List possible causes of chronic endothelial cell damage that can lead to an inflammatory response, macrophage recruitment, and LDL oxidation.

Carotenoids cannot be produced by the human body, and need to be consumed in the diet. • Macula is the most sensitive part of the retina. The center of the macula is the fovea centralis, containing millions of cones tightly packed. Macula degeneration leads to blindness, and there is no cure. • Age increases the risk of macular degeneration, and several other factors have been involved, but the exact causes are not known yet. • High levels of lutein and zeaxanthin are found in the macula of the retina. • Higher intakes of lutein and zeaxanthin are associated with low risk of age- related macular degeneration and senile cataracts. It is believed that lutein and zeaxanthin: (i) protect against photo-damage by filtering out blue light (high energy visible light), (ii) protect the photoreceptor membranes from oxidation, and (iii) protect blood vessels

Lutein and zeaxanthin (Carotenoids)

recruited to phagocytize the necrotic adipocytes The number of resident macrophages in adipose tissue increases from 10-15% in the lean (mostly M2 anti-inflammatory), to 40 to 60% in the obese (mostly M1 proinflammatory). In the obese, M1 macrophages release proinflammatory cytokines (e.g. tumor necrosis factor α (TNF α), plasminogen activator inhibitor 1 (PAI-1), angiotensin II (AGT II), etc.) which contribute to inflammation and insulin resistance. H2O2 is released as a byproduct of M1 activity in obesity

M1 Macrophages promote Insulin Resistance

The goal of treatment is reperfusion of the affected tissue as soon as possible. This can be accomplished using mechanical means (percutaneous coronary intervention (PCI): angioplasty with stenting) or thrombolytic therapy. PCI usually achieves superior outcomes with fewer complications and is generally used if the duration of the symptoms is <12 hours. PCI may also be considered between 12-24 hours after symptom onset if there is evidence of ongoing ischemia. Unfortunately, some hospitals are not equipped to do PCI. Hospitals that are not equipped frequently form networks with hospitals that do have the capability, and transfer patients to them when possible. Note: Reperfusion therapy can result in a surge in cardiac markers as blood flow is restored and can therefore affect the results of serial testing.

MI acute care

acutely treated with an IV heparin as well as thrombolytic (fibrinolytic) agent such as tPA. Both of these drugs have immediate effects. The heparin dose is adjusted over a couple of days using aPTT monitoring. Thrombolytic agents vary in administration protocols, some are a single bolus and other require a bolus and then one or more subsequent doses. Aspirin is generally administered to any patient suspected of having a myocardial infarction, before testing is even performed. Nitrates are also often given immediately to induce vasodilation.

MI acute drug therapy

The antithrombotic drugs are divided into drugs that reduce fibrin clot formation (e.g. warfarin) and drugs that reduce platelet aggregation (e.g., ticagrelor (Brilinta), clopidogrel [Plavix], acetylsalicylic acid [aspirin]). Besides medical treatment, typical recommendations are for lifestyle and dietary changes.

MI long-term care

Peripheral resistance Leptin signaling increases sympathetic nervous system(SNS) (increase in epinephrine, norepinephrine) and T3, all of which increase blood pressure Insulin resistance Decreased NO formation Increased endothelin 1 (ET-1) Angiotensinogen (made in and released from adipocytes & M1 macrophages) Promotes vasoconstriction and sodium retention Weight loss of as little as 5-10% of initial weight can significantly lower BP

Mechanisms of Hypertension in Obesity

= no effect on drug metabolism (The alcohol dehydrogenase can handle the alcohol by itself.)

Moderate amount of alcohol plus presence of drug

- Smoking - Obesity - Hypertension (BP≥130/80 mm Hg or taking antihypertensive medication) - Diabetes (TypeII) - Physical inactivity

Modifiable risk factors - Nonlipid for heart disease

▪ Dopamine (DA)* ▪ Norepinephrine (NE)* ▪ Epinephrine (EPI)* ▪ Serotonin (5HT)*

Monoamines include:

Monocarboxylates can be used for energy production in the brain. They must be transported across the endothelial cells from the blood, and navigate into and between astrocytes & neurons. • Monocarboxylate transporters are a family of H+ coupled symporters. Isoforms (MCT1,2, & 4 are found in nervous tissue.) • MCTs transport hydrophilic monocarboxylate metabolites in and out of cells. • Ketone bodies: MCT expression level is rate limiting for ketone catabolism.

Monocarboxylate Transporters (MCTs)

When dietary saturated fatty acids are replaced with monounsaturated fatty acids: 1) total cholesterol and LDL- cholesterol decrease 2) HDL-cholesterolremains unchanged Increased dietary MUFAs are believed to decrease the risk of heart disease Olive oil contains a large amount of the MUFA oleic acid (18:1) Canola and safflower oils are also good sources of MUFAs

Monounsaturated Fatty Acids (MUFAs)

glucose: AMPK, epinephrine activate PFK2; F2,6BP activates glycolysis lactate: During more intense exercise, blood lactate levels rise and serves as major AEROBIC fuel for heart FFAs: AMPK --> ACC2 inhibition, low malonyl CoA --> increase FA oxidation

Multiple energy sources required to meet heart energy demands during exercise

contain tyrosine hydroxylase and AADC.

Neurons that produce Dopamine

contain Dopamine β -hydroxylase

Neurons that produce Norepinephrine

oppose weight loss stimulate appetite (orexigens), while decreasing RMR and fertility

Neuropeptide Y (NPY) and agouti-related protein (AgRP)

- Age:men >45 years of age, women> 55 years of age - Family history of premature heart disease defined as a heart attack before the age of 55 in men or 65 in women

Non-modifiable risk factors for heart disease

Nonalcoholic fatty liver disease (NAFLD) develops in the absence of alcohol abuse but produces very similar pathology, i.e. deposition of fat in the liver. Development of NAFLD is most often associated with risk factors characteristic of metabolic syndrome: obesity, diabetes, high cholesterol or high triglycerides. NAFLD can also develop in the absence of obvious risk factors, even in very healthy, active individuals. Can be associated with rapid weight loss or poor diet. Affects ~25% of people worldwide. It can develop into nonalcoholic steatohepatitis (NASH). Often asymptomatic, but symptoms can include weakness and fatigue, spider angiomas, abdominal pain, nausea, jaundice, and edema. The liver may swell, resulting in cirrhosis (scarring). Liver enzymes may be elevated.

Nonalcoholic fatty liver disease

through methylation catalyzed by PMNT

Norepinephrine is converted to epinephrine

Due to the limited availability of oxygen, a terminal electron acceptor for the ETC, the electron transport chain slows, greatly reducing the level of oxidative phosphorylation that would otherwise be used to synthesize ATP.

Normally the heart muscle can metabolize lactate to pyruvate to produce ATP (via the TCA cycle and the electron transport chain). Explain why that does not occur when patients experience a myocardial infarction, despite abundant available lactate:

produced in Ileum & colon in response to Caloric intake (proportional) ↓ Gastric emptying↓ Appetite (blocks NPY receptor)

Peptide YY (PYY)

Perivenous hepatocytes are ideal for drug metabolism because they have an extensive SER and an active HMP shunt (NADPH production) Metabolism of xenobiotics (including drug metabolism) is divided into two phases: Phase I reactions: a hydrophilic functional group (e.g. -OH, -NH2, - SH)isintroducedorunmaskedbyenzymesintheSER. These enzymes catalyze oxidation, reduction, or hydrolysis reactions. Phase II reactions: a hydrophilic group is added/conjugated to xenobiotic. Added groups include glucuronate, acetate, glutathione, taurine and glycine.

Perivenous hepatocytes and drug metabolism

occurs in the SER Nearly all drug metabolism involves one of three families of cytochrome P450 monooxygenases: CYP1, CYP2 and CYP3. Monooxygenases are located in SER and, out of necessity, have a low substrate specificity (~50 cytochrome P450 enzymes have to hydroxylate ~20,000 compounds!). The cytochrome P450 monooxygenases hydroxylate xenobiotics/drugs using NADPH as the source of reducing equivalents. The enzymes also require oxygen and generate superoxide radical intermediates (often referred to as reactive oxygen species (ROS)).

Phase I of drug metabolism

conjugation reactions in the cytosol An important conjugation reaction is glucuronidation (addition of glucuronic acid) catalyzed by UDP glucuronosyltransferase. Groups such as sulfate, glutathione and amino acids (e.g. taurine, glycine and glutamine) are also used for conjugation. Phase 1 often creates a site where these groups can ultimately be attached. • ThepurposeofphaseIandphaseIIdrugmetabolismisto increase the water solubility of lipophilic xenobiotics, so they can be more easily excreted. Active drugs are often inactivated as a consequence of phase I and II metabolism. Pro-drugs and other inactive compounds may be activated as a result of drug metabolism, or nontoxic compounds may be converted into toxic derivatives. • For example, heterocyclic amines (generated when food is grilled) are initially harmless but become carcinogenic because of reactions catalyzed by cytochrome P450 enzymes.

Phase II of drug metabolism

tumors of the chromaffin cells of the adrenal gland. It is characterized by overproduction of adrenergic hormones. Enzymatic breakdown of catecholamines in the liver results in elevated adrenergic metabolites: normetanephrine, metanephrine & vanillylmandelic acid (VMA) which can be measured in the blood or plasma. The name comes from a reaction these tissues have with chromium salt.

Pheochromocytomas

Opsins are light-sensitive G protein-coupled receptor proteins. Both rods and cones contain 11-cis-retinal in their photoreceptors. Light converts 11-cis-retinal into all-trans retinal.

Photoreceptor = opsin (protein) + 11-cis-retinal (prosthetic group)

It recommends 150 minutes/week of low to moderate intensity exercise, 90- minutes aerobic and 60-minutes resistance training. The same prescription is used for prevention as well as treatment of type 2 diabetes mellitus.

Physical Activity Guidelines for Americans

Plantstanols/sterolsaresimilarinstructuretocholesteroland are found in all plant foods, with the highest concentrations in vegetable oils. Currently, average daily intake of combined stanols and sterols is <0.5 g per day. Cholesterolhastobeincorporatedintoamixedmicelletobe absorbed, otherwise it is lost in the stool. Stanols/sterolscompetewithdietaryandbiliarycholesterolfor incorporation into mixed micelles. Stanols/sterolscanlowercholesterolbutareonlyeffectivewhen they are taken with a meal. LDL-cholesterolisloweredby7.5to12%when1.5to3gof stanols/sterols are incorporated into the diet every day. • Stanols/sterolsareusedincertainmargarines(ex:Benecol) and are sometimes added to other foods. Stanols and sterols can also be purchased at a health food store. • Verylittleofthestanols/sterolsthemselvesareretainedby the body.

Plant Stanol/Sterol Fortified Foods

• When PUFAs are used in place of saturated fat they have a direct LDL-cholesterol lowering effect • Replacing saturated fat with the PUFA linoleic acid (18:2 ω-6) increases LDL receptor activity and decreases serum LDL- cholesterol (no effect on HDL) Good sources of PUFAs: various seed oils, walnut oil and soybean oil Recommendations: Replace saturated fats with PUFAs, but PUFAs should make up <10% of total caloric intake

Polyunsaturated Fatty Acids (PUFAs)

1) The low saturated fat control diet lowered LDL-cholesterol 8% 2) Low saturated fat plus Lovastatin lowered LDL-cholesterol 30% 3) The Portfolio diet lowered LDL-cholesterol 28%

Portfolio Diet vs Lovastatin

inverse relationship A high-potassium diet(i.e. lots of fruits and vegetables) is associated with a decrease in blood pressure in people with or without HTN Potassium facilitates sodium excretion by the kidney and minimizes the chances of a slightly positive, sodium balance A low-potassium diet results in sodium retention and an increase in BP Low-potassium intake may be a more important factor than a high-sodium intake in the hypertension seen in African-Americans. Potassium supplements arenot recommended for patients with kidney disease, heart failure or using some drugs (e.g. ACE inhibitors, angiotensin II receptor blockers or potassium-sparing diuretics)

Potassium Intake and BP

Anti-Coagulation: Directly binds to the active site of thrombin (factor II). Prevents thrombin from cleaving fibrinogen into fibrin, and prevents activation of other clotting factors. long term

Pradaxa (dabigatran) mechanism of action and of the drugs used to treat/prevent heart attack.

oppose weight gain POMC neurons produce α-melanocyte stimulating hormone (α-MSH) which decreases appetite and increases RMR (anorexigen).

Pro-opiomelanocortin (POMC) neurons

Triceps: 33% type I fibers Soleus (maintains posture): >70% type I fibers

Proportion of fiber types varies from muscle to muscle and person to person (triceps vs soleus)

based on the protein's molecular weight and net charge (with the former being more important). §Molecular weight:• Filtration rate progressively decreases as protein molecular weights increase from 5,000 to 75,000 daltons (Da) à'size selectivity' • Compounds <5,000 Da are easily filtered • Proteins >75,000 Da are not filtered• Note: glucose is 180 Da; insulin is 5,800 Da; and glucagon (3,500 Da) §Net charge:• The glycocalyx and glomerulus basal membrane are negatively charged because of glycosaminoglycans (GAG)àhence they impede the passage of negatively charged proteins ("like repels like").• Neutral proteins are more easily filtered than negatively charged proteins of a similar size.• Note : albumin is negatively charged §The filter is always clean and filtration barrier never becomes clogged— macrophages clean up any debris.

Protein filtration at the glomerulus

• In addition to reabsorbing filtered proteins, the PCT reabsorbs ~99% of all filtered glucose and amino acids and ~85% of NaCl and HCO3-. • Water follows solute reabsorption The apical surfaces of these cells have abundant microvilli which increases membrane surface area 40-fold, thus maximizing absorptive capacity.

Reabsorption of Renal-Filtered Protein at Proximal Convoluted Tubule

1: Filtration at glomerulus 2a: Filtered proteins are reabsorbed in the proximal tubule cells via receptor-mediated endocytosis 2b: Reabsorbed proteins are degraded in lysosome; resulting amino acids are released into the circulation: • e.g., insulin (5,800 Da) and glucagon (3,500 Da) are easily filtered at the glomerulus, reabsorbed and degraded in the lysosomes of the PCT. 3: Proteins that escape reabsorption are lost in the urine

Reabsorption of Renal-Filtered Protein at Proximal Convoluted Tubule steps

accomplished using Na+ in Na+-driven co-transporter, e.g., thru secondary active transport mechanism. • In the tubule wall, the glucose and amino acids diffuse directly into the blood capillaries along a concentration gradient. This blood is flowing, so the gradient is maintained.• Na+-K+ pump (active transport pumps) remove Na+ from the tubule wall and back into the blood.

Reabsorption of glucose (and smaller amino acids) by PCT

Thrombolysis: Binds to fibrin with high affinity and cleaves fibrin- bound plasminogen into plasmin. Plasmin degrades fibrin clots, allowing reperfusion. acute

Recombinant t-PA mechanism of action and of the drugs used to treat/prevent heart attack.

Within an individual, daily food consumption can vary as much as 20-25%, yet body weight is relatively consistent CNS balances variation in food intake by altering energy expenditure and appetite to achieve weight stability Changes in appetite and RMR cannot keep up with chronic, long-term energy imbalance CNS stabilizes energy balance to within ~20 kcal/d (balancing occurs over a 3- to 4-day period, NOT daily). We are completely unaware of this.

Relative Weight Stability Despite Large Variations in Food Consumption

• The proximal tubule is the primary site for renal ammoniagenesis. • Renal ammoniagenesis results in ammonia being released directly into urine, thus reducing the need for urea synthesis. • Renal ammoniagenesis is coupled to renal gluconeogenesis.

Renal Ammoniagenesis

1 Ammonium (NH4+) is generated from glutamine. 2 Glutamine is converted to α-ketoglutarate and ammonium by glutaminase and glutamate dehydrogenase. 3 The ammonium is transported into the renal lumen in exchange for Na+. 4 The ammonium is then excreted into the urine. 5 This generates HCO3- (bicarbonate) via glutamine metabolism. HCO3- is returned to the blood.

Renal Ammoniagenesis in the tubule cells steps

Group of hereditary eye disorders with gradual degeneration of photoreceptors. Initial difficulty seeing at night, followed by loss of peripheral vision and eventually loss of color vision and blindness. Mutations in more than 30 different genes are responsible for retinitis pigmentosa, although the most common one is a mutation in rhodopsin.

Retinitis pigmentosa

Glucose metabolism provides the pyruvate needed to keep the TCA cycle running via an anaplerotic reaction. (Pyruvate is converted to oxaloacetate (OAA) using pyruvate carboxylase.) Extra blood glucose spares muscle glycogen in type I fibers so she can run longer. If TCA cycle slows down, there will be a decrease in ATP production and fatigue will occur. Conventional athletes who consume a sports drink (30 to 60 g of glucose/hr) report that it postpones physical and mental fatigue associated with strenuous endurance exercise that lasts more than one hour.

Rose finds that she is less physically and mentally tired if she consumes a sugary beverage during the long run. What is the underlying biochemical mechanism for this phenomenon? (Hint: "fat burns in the flame of carbohydrate".)

For treatment of type 2 DM patients, SGLT2 inhibitors lead to enhanced urinary excretion of glucose which will lead to a reduction of HbA1c of up to ~1.0%. • decreases glucose reabsorption by 30- 50%• would prevent kidney failure in patients with type 2 diabetes and provide protection against acute kidney injury • does not affect glucose absorption in GI tract, which is handled by SGLT1

SGLT2 inhibitors

Exercise for 1.5 hours/d, seven days/week Consume 50-300 Kcal/d less than most people at their present weight Formerly obese individual will require fewer calories per day to maintain the same body weight and physical activity level as a never-obese individual of the same body weight and composition. IN J Obes (Lond) 2010 October; 34 (0 1): S47-S55 Consume a diet low in caloric density/high in nutrient density (e.g. foods with higher protein, lower glycemic index and lower fat, containing lots of vegetables and fruits). Weigh themselves frequently

STRATEGIES TO PREVENT REGAINING WEIGHT

Studies show that saturated fatty acids increase LDL-cholesterol levels. - Increased dietary SFAs can result in a decrease in the number of hepatic LDL receptors. - Most studies do not show an increase in LDL-cholesterol synthesis. Myristic (14:0) and palmitic (16:0) fatty acids, commonly found in red meat and dairy products, are the most closely associated with increases in LDL-cholesterol. Dietary Sources of SFAs: Milk and milk products are a major source of dietary SFAs. - Cheese is the leading source of SFAs in the American diet. Red meat has significantly more SFAs than meats like chicken. NCEP / ATP III recommends that SFAs compose <7% of daily caloric intake. - Currently, on average SFAs make up 11% of daily caloric intake of Americans

Saturated Fatty Acids (SFAs)

Hyperglycemia and subsequent increase in the production of ROS ↑ Production of heparanase Heparan sulfate cleaved; ↑ Filtration rate for albumin Albuminuria

Sequence of events for Diabetic Albuminuria

Serotonin Selective Reuptake: Transporters for serotonin "vacuum" leftover neurotransmitters in the cleft. Enzymatic Degradation: Monoamine Oxidase enzymatically degrades serotonin into its metabolite, 5-hydroxindoleacetic acid Serotonin Autoreceptors: Serotonin selective autoreceptors open K+ channels in the presynaptic terminal, inhibiting voltage gated Ca2+ channels.

Serotonin in the cleft is removed via:

• The shift in gluconeogenesis from the liver to the kidney is orchestrated by the rise in H+ ions from excess ketone bodies (fasting) or an acidosis. • During long-term fasting and acidosis, the rate of hepatic amino acid catabolism will remain constant.• Carbon skeletons are diverted from hepatic gluconeogenesis and are used to make more glutamine. • Glutamine is then used to make glucose (gluconeogenesis) and to make ammonia (ammoniagenesis) to eliminate nitrogen by the kidney. • Overall, total glucose production does not change even though the location of gluconeogenesis does change (i.e., portion from kidney is increased during acidosis).

Site of gluconeogenesis is shifted from liver to kidney during fasting and/or acidosis

Enhance muscle mass (Type II hypertrophy), more power, anaerobic capacity (greater CrP store, anaerobic glycolysis capacity, and buffering capacity) Increase activities of glycogen phosphorylase, glycolytic enzymes (e.g., PFK1), lactate dehydrogenase Increase expression of lactate transporters in muscle Increase creatine kinase and adenylate kinase activities Increase muscle buffer capacity • Training can increase muscle buffer capacity by as much as 40-50% due to more intracellular buffering molecules

Speed/sprint and resistance training will...

• Tetrahydrobiopterin (BH4) functions as a cofactor for three enzymes important for NT synthesis: • Phenylalanine hydroxylase: produces tyrosine in the liver (Phe→Tyr) • Tyrosine hydroxylase: used in catecholamine synthesis• Tryptophan hydroxylase: used in serotonin synthesis • Individuals with genetic deficiencies affecting biosynthesis or recycling of BH4 exhibit neurological deterioration that cannot be rescued by reduced phenylalanine intake. This deficiency is clinically referred to as "malignant PKU." • Sapropterin, a synthetic analog of BH4 is used to treat BH4 deficiency and certain cases of PKU.

Tetrahydrobiopterin (BH4) deficiency

Excess ω-6 arachidonic acid, unbalanced by ω-3 fatty acid, may increase coronary atherosclerosis and sudden cardiac arrhythmic deaths The Mediterranean diet uses olive oil (77% MUFA and very low in ω-6) which replaces the plant seed oils. When used with ω-3 supplements or meals of fatty fish, the balance of ω-3 to ω-6 fatty acids is improved. - The current ratio of ω-3 to ω-6 fats in American diet is 1:17, recommended goal is 1:1 - Plant seed oils, which are common in the US, are on average composed of 70% ω-6 fatty acids with little ω-3 fatty acids

The Ratio of ω-6 to ω-3 Dietary Fatty Acids is Important!

Thrifty (increased metabolic efficiency) Sedentary (NEAT is an inheritable trait) Hyperphagic (appetite regulation) Low-lipid oxidation (adaptive thermogenesis)

The genes favoring obesity create a positive-energy balance and are divided into four categories:

1 Fenestrated capillaries and their associated glycocalyx function as a coarse filter (good). • Endothelial cells are fenestrated • Fenestrated capillaries are characterized by the existence of pores with the endothelial cells and form specialized regions of the capillary bed • Fenestrations function as a coarse filter 2 Glomerular basement membrane (GBM; basal lamina) is the main filter with a small pore size. • In addition, the anionic charge formed of proteoglycans block entry of mast large proteins (better) 3 Slits formed by podocyte foot processes function as a fine filter (best). Podocytes use receptor-mediated endocytosis to remove any proteins and immunoglobulins that accumulate at the filtration barrier.

The glomerular filter has three barriers with increasing selectivity

facilitates the flow of water into the posterior chamber, resulting in production of aqueous humor. Acetazolamide is a potent inhibitor of carbonic anhydrase: it lowers the concentration of HCO3- in the aqueous humor, resulting in decreased osmotic water flux and decreased intraocular pressure.

The osmotic gradient established by accumulation of ions and other solutes in the posterior chamber of aqueous humor

It has a dual blood supply(i.e., choroid for photoreceptors, retinal vessels for inner retina). Mitochondria and active respiration are present in retinal rods and cones. Retina has also a significant aerobic and anaerobic glycolysis for energy production.

The retina is metabolically active tissue.

(i) Na+ out and K+ in by Na+/K+ ATPase (ii) K+ out by K+ channel (iii) cGMP-gated Na+ channel is open (Na+ in) cGMP is produced by guanylyl cyclase leads to Depolarization (-30mV) leads to Voltage-sensitive Ca2+ channel open leads to Release of inhibitory neurotransmitter (glutamate) The inward movement of positively charged Na+ ions makes the inside of rod cells less negatively charged (i.e., depolarized)

The rod phototransduction cascade: Dark

Rhodopsin activation to cGMP decrease to (i) cGMP-gated Na+ channel is closed (No inward movement of Na+) (ii) Na+ out and K+ in by Na+/K+ ATPase (iii) K+ out by K+ channel to Hyperpolarization (-65mV) to Voltage-sensitive Ca2+ channel close to Release of inhibitory neurotransmitter (glutamate) Outward movement of (+) charges > Inward movement of (+) charges to Hyperpolarization (i.e., the inside becomes more negatively charged)

The rod phototransduction cascade: Light

Glucose in fed state; fatty acids and ketones during fasted state

Thick ascending Loop of Henle fuel preference

Glucose • The thin loop of Henle, especially that portion located in the inner medulla, is primarily limited to anaerobic glycolysis in both the fed and fasted state.

Thin loop of Henle / Inner medulla fuel preference

leading to increased renal gene expression (by 3 to 20-fold). • genes coding for glutaminase and glutamate dehydrogenase. • H+ ions act as a positive allosteric effector of a-ketoglutarate dehydrogenase (a- KGDH). • The activation a-KGDH ensures that the a-ketoglutarate generated from ammoniagenesis enters the TCA cycle.

Three enzymes in the PCT are regulated by increasing [H+] ions

An unstable plaque (with a thin fibrous cap) may rupture, which can result in the formation of a blood clot (thrombus). This is due to exposure of subendothelial elements (such as tissue factor) which can initiate coagulation. The blood clot may block the vessel in which it's located or may break off and cause the blockage of a vessel in another location (embolus).

Thrombus Formation

Antiplatelet: block platelet ADP receptors, inhibit activation. Prevents formation of arterial thrombi. long term

Ticagrelor (Brilinta), Clopidogrel (Plavix) mechanism of action and of the drugs used to treat/prevent heart attack.

released from the vascular endothelium upon stress or injury. Recombinant tPA can be administered as a thrombolytic to patients who have experienced an acute clotting event.

Tissue plasminogen activator (tPA)

Trans fatty acids (from partially hydrogenated vegetable oil) are structurally similar to SFAs and are clearly associated with an increased risk of heart disease. - Partial hydrogenation converts oils into solids and increases the shelf life of products made with TFAs Trans fats, just like saturated fats, increase LDL-cholesterol However, trans fats also lower HDL-cholesterol, whereas saturated fats have no effect on HDL-cholesterol. This makes trans fats more harmful.

Trans Fatty Acids (TFAs)

avascular (i.e., lack of blood vessels) no mitochondria sparsity of cells (i.e., single layer of epithelial cells)

Transparency of lens results from

Slow-Oxidative Triacylglycerol High/Red myoglobin High mito density: 50% of cell volume High capillary density small fiber size Hours- Fatigue resistant

Type I Fibers

Fast-Glycolytic CrP, Glycogen low/white myoglobin low mito density: 20% low capillary density large fiber size <5 minutes, fatigue prone

Type IIX Fibers

Fast-Oxidative Glycolytic CrP, Glycogen Intermediate myoglobin intermediate mito density 35% intermediate capillary density medium fiber size <30 minutes

Type IIa Fibers

Two types of photoreceptor cells are present in the retina: rods and cones. Both rods and cones consist of (i) Outer segment which contains about 1,000 membranous disks densely packed with the light-sensitive photoreceptors (or pigment). It is here where the signal transduction process starts. (ii) Inner segment, containing the nucleus and mitochondria (iii) Synaptic terminal, contacting with other neurons by releasing the neurotransmitter glutamate.

Visual phototransduction: photoreceptors

Foods of animal origin and dairy products (retinyl esters) β-carotene (progenitor of vitamin A) fruits and vegetables Retinol and its derivatives are required for maintaining a healthy epithelial tissue. Retinal is essential for the production of the photoreceptor (e.g., rhodopsin). Retinoic acid inhibits keratin synthesis. Retinyl phosphate is required for the production of glycoproteins, an important component of the mucus secreted by many epithelial cells.

Vitamin A (retinol)

Vitamin A deficiency can cause night blindness (∵ impaired production of rhodopsin). • Vitamin A-deficient individuals experience replacement of normal mucus- secreting cells by cells that produce keratin, particularly in the conjunctiva and cornea of the eye. Increased keratinization of epithelium & lack of mucus secretion as a result of vitamin A deficiency Bitot's spot (a keratinized surface of the conjunctiva with excess of keratin synthesis, arrow in the figure) is often observed. Severe vitamin A deficiency can result in xerophthalmia (a pathological dryness of the conjunctiva and cornea) In the final stages of xerophthalmia, infection usually sets in, with resulting hemorrhaging of the eye and permanent loss of vision. It is a common cause of blindness in developing countries.

Vitamin A deficiency

No significant difference between the amount of weight lost on either low-carbohydrate or low-fat diets. One only has to lose 7 to 10% of bodyweight to gain health benefits

Weight loss is determined by number of calories and not nutrient composition of the diet

-AMP and Pi levels rise through energy consumption (ATP -> ADP + Pi) and the action of adenylate kinase: ADP + ADP -> AMP + ATP - Pi and AMP directly activate glycogenolysis (via glycogen phosphorylase) and AMP activates glycolysis (allosterically via PFK-1) - increase AMP also activates AMPK, which generally acts to inhibit ATP-consuming processes and upregulate ATP-generating processes (e.g., further activating glycolysis) - Accelerated glycolysis and concomitant ATP production maintain cell function and prolong viability for a short time.

What are the regulatory mechanisms that would lead to the Pasteur Effect?

Exercise increases epinephrine which increases HSL activity Increase in AMP leads to AMPK activation resulting in the following. o Vasodilation due to increase in NO production. Vasodilation allows enhanced ability to transport FAs, glucose, and O2. o GLUT4 translocationo Inhibition of acetyl CoA carboxylase-2 (ACC-2) and activation of malonyl CoA decarboxylase (MCoADC) which leads to lowering of malonyl CoA levels A "second wind" is quantifiable by lowering of pain and heart rate. All of the above will increase insulin sensitivity.

What biochemical events lead to the greater utilization of fatty acids which is responsible for this "second wind"?

Lose weight Exercise Consume moderate levels of alcohol Avoid trans fats

What dietary or lifestyle factors/changes are associated with an increase in serum HDL?

Genetics(familyhistory,heritabilityisstrong) Totalcholesterollevels≥300mg/dLalmostalways have a genetic component Age(cholesterollevelscanincreasewithage) Smoking Gender(mentendtohavehighercholesterol) Obesity Sedentarylifestyle Atherogenicdiet(highinsaturatedortransfats)

What factors are associated with high serum cholesterol?

Cornea is exposed to atmospheric oxygen and sunlight including the ultraviolet range, causative factors of oxidative stress in biological systems. Recycling of GSSG to GSH (for detoxification of ROS) requires glutathione reductase and NAPDH. HMP shunt is the major source of NADPH in cells with few mitochondria

Why is HMP shunt so active in the cornea?

"foreign compounds" (e.g. phytochemicals, toxins, drugs.) Plants contain ~20,000 different phytochemicals (xenobiotics) Xenobiotics are often lipophilic making them more problematic because: 1) they can more easily cross the plasma membrane and enter the cell and 2) they are often difficult to excrete • Some xenobiotics are potentially toxic, especially to the brain and/or fetus Xenobiotics/drugs are metabolized to increase their hydrophilic properties making them easier to excrete in the urine and/or bile. Once in the colon, compounds may be further metabolized by intestinal flora. • Amphipathic compounds are often reabsorbed via enterohepatic circulation and re-excreted by liver.

Xenobiotic compounds

An inability of the liver to metabolize some xenobiotics to non-toxic or easily excretable forms can result in hepatocyte cell necrosis and the release of liver transaminases like ALT. Exposure to the amatoxin in Amanita phalloides is often lethal. Amatoxin is, unfortunately, NOT destroyed by cooking and has poisoned many people.

Xenobiotic-induced hepatocyte necrosis

n alcoholics, acetaminophen is potentially dangerous (especially when alcohol levels in the body are low, such as first thing in the morning) as it is rapidly metabolized by CYP2E1 to a hepatotoxic intermediate, which is usually rendered nontoxic by conjugation with glutathione (GSH). However, once GSH is depleted, the toxic intermediate will build up and damage liver cells.

acetaminophen in alcoholics

One function of BAT is to produce heat and dissipate energy via thermogenesis BAT-mediated heat production is termed adaptive thermogenesis Adaptive thermogenesis is activated in response to cold, diet, infections and stress BAT responds to a positive-energy balance by increasing heat production Diminished ability to induce adaptive thermogenesis may be a contributing factor for obesity

adaptive thermogenesis

ADP + ADP <->ATP + AMP (aka myosin kinase) quickly produces ATP and generates AMP -AMP is Potent signaling molecule, activates glycogenolysis and glycolysis and increases NO (vasodilator) release

adenylate kinase

another peptide adipokine secreted by adipocytes Levels are inversely proportional to quantities of WAT Weight loss increases adiponectin levels

adiponectin

Adiponectin is cardiovascular protective Increases endothelial nitric oxide production

adiponectin and heart health

anti-inflammatory Suppresses macrophage conversion to proinflammatory state, M2 M1

adiponectin and inflammation

Adiponectin acts by increasing insulin sensitivity Adiponectin increases the activity of AMPK Increases glucose clearance (muscle)- Lowers blood glucose Decreases gluconeogenesis (liver)- Lowers blood glucose Lowers insulin resistance by increasing ceramidase activity (ceramides contribute to insulin resistance) Increases glucose-dependent insulin secretion Increases fat storage in subcutaneous adipocytes

adiponectin effects on insulin sensitivity

Research has shown that moderate alcohol intake (≤ 2 drinks/day for men, ≤ 1 drink/day for women) decreases the risk of heart disease by 20-40% ~50% of the effect is due to an increase in HDL-cholesterol The protective effect is independent of beverage type.

alcohol and cardiovascular disease

located in the cytosol and is the major pathway for hepatic alcohol metabolism • ADH is a high-affinity, low-capacity enzyme (Km = 0.2 - 2.0 mM)• Increased levels of NADH produced during the reaction can alter the oxidative state of the liver

alcohol dehydrogenase

Clear, watery liquid that fills the anterior and posterior chambers • Functions of AH Composition is similar to plasma, but protein concentration is much lower. (i) Generates & maintains the intraocular pressure (ii) Supplies nutrients to and carries away wastes from avascular structures that it bathes: cornea, lens, trabecular meshwork and anterior vitreous (iii) Maintains optical transparency AH is continuously produced by the epithelium of ciliary processes (i.e., finger-like projections of the ciliary body) AH production must be balanced with drainage to maintain constant intraocular pressure. Glaucoma is a failure of adequate drainage, resulting in high intraocular pressure and consequent retinal neurons damage.

aqueous humor

Most common cause of death in North America (myocardial infarction and ischemic strokes) Result of rupture of atherosclerotic plaques and subsequent exposure of thrombogenic factors Referred to as "white clots", comprised mostly of platelets, with less fibrin or RBCs

arterial thrombosis

Many Asians have an aldehyde dehydrogenase (ALDH2 specifically) with an unusually high Km (low binding affinity). This results in the accumulation of acetaldehyde which causes flushing and palpitations (decreases risk of alcoholism).

asian aldehyde dehydrogenase

Antiplatelet: inhibitor of COX-1 (remember platelets do not express COX-2), results in decreased platelet agonist thromboxane A2, inhibiting platelet activation/degranulation. Decreases platelet plug formation. acute and longterm

aspirin mechanism of action and of the drugs used to treat/prevent heart attack.

"hardening of the arteries" This is a chronic inflammatory process in the walls of the arteries producing atheromatous (atherosclerotic) plaques. Cholesterol and triacylglycerol (TAG) accumulate, leading to formation of the plaques in the walls of the arteries. This process involves macrophage as well as low density lipoproteins (LDL), which carry cholesterol and TAG. Calcification can occur around the edges of the lesion. Elasticity is lost, the artery is narrowed, blood flow is compromised, and blood pressure may be increased. Atherosclerotic plaques may rupture, leading to formation of blood clots (thrombi).

atherosclerosis

"Beige" (aka "Brite" [brown-in-white]) adipocytes are derived from white adipocytes in response to a positive-energy balance Like brown adipocytes, beige adipocytes produce heat and dissipate energy Beige adipocytes are formed in response to sympathetic nervous system (SNS) stimulating β3-Adrenergic receptors on white adipocytes which increases the expression of the gene coding for mitochondrial UCP1 (hallmark of beige adipocytes) The color of beige adipocytes is due to less myoglobin and fewer mitochondria than their brown adipocyte counterparts It's hypothesized that some obese people may have fewer beige adipocytes than lean individuals and therefore would be more "metabolically efficient" (i.e. produce less heat and gain more weight on a high-calorie diet) than a lean individual

beige adipose tissue

via a two-pronged strategy: decrease caloric intake and increase energy expenditure (exercise) to facilitate weight loss.

best way to deal with metabolic syndrome and the increased risk of T2DM

weight loss -> decrease in leptin (which normally inhibits release of NPY & AgRP) and increases NPY/AgRP --> stimulate appetite and decrease RMR weight loss -> decrease in leptin -> NPY/AgRP -> inhibit release of α-MSH & blocks α-MSH binding MC4R (which normally lowers appetite and increases RMR)

biochemistry of difficulty of weight loss

from the brain is restricted, mostly to waste.

blood brain barrier efflux

bound to the cell wall degrade and limit the intake of neurotransmitters and toxins present in the blood.

blood brain barrier enzymes

the luminal membrane (facing the bloodstream) is more permeable and less selective than abluminal membrane (facing the brain).

blood brain barrier membranes

Various channels and carriers on the luminal (blood) or abluminal (brain) side of the endothelial cell enable selective filtration of ions and molecules during transcellular ("through cell") transport. Minimal vesicular trafficking limits transcytosis.

blood brain barrier selective transport

High in astrocytes and endothelial cells Low Km (~1mM): high affinity allows near constant uptake from bloodstream

brain GLUT1

High in neurons Low Km (<1mM): allows preferential uptake during hypoglycemia

brain GLUT3

• Brain AA uptake is selective and limited, mediated by differential expression and membrane distribution of transporters. • Most essential AAs are transported INTO the brain by facilitated transport, via the L-system transporter (LAT1). Substrates for this transporter include leu, val, met, his, iso, tyr, trp, phe, thr. • Luminal:abluminal distribution on endothelial cells is 2:1• Substrates may compete for transport. (for instance Phe in PKU) • Transport out of the brain through abluminal membrane is primarily handled by Na+ dependent symporters. They transport AA OUT of extracellular fluid against their concentration gradient into the endothelial cells. • This mechanism is very important in maintaining glutamate/glutamine homeostasis.

brain amino acid transport mechanism

between endothelial cells create ahigh-resistance to paracellular ("between cell")transport.

brain tight junctions

Turbulence at branch points can increase formation of plaques

branch points in blood vessels

BAT is abundant in infants and decreases with age making up~4% of the total fat mass in adults Brown adipocytes are multilocular(i.e. have several lipid droplets) and contain myoglobin and numerous mitochondria Myoglobin and mitochondria are responsible for the tissue's characteristic brown color BAT is well vascularized, just the opposite of WAT Brown adipocytes are derived from smooth muscle

brown adipose tissue

is more like Type I muscle fibers • Heart designed for endurance: more mitochondria, little glycogen • 98% ATP generated by oxidative means • Prefers FAs over KBs (spares KBs for nervous system); heart contains numerous lipid droplets • Lactate from RBCs and skeletal muscle: lactate oxidized to pyruvate --> acetyl-CoA --> TCA --> ETC/OxPhos

cardiac muscle metabolism

located in peroxisomes, plays a minor role in alcohol metabolism. • Catalase oxidizes ethanol using hydrogen peroxide • Catalase's contribution to alcohol metabolism increases during a fast because the number of peroxisomes will increase during a fast

catalase

(lens opacities = loss of transparency) #1 cause of blindness worldwide Two types: (i) senile cataracts (age-related) and (ii) diabetic cataracts Biochemical basis of diabetic cataracts (i) Normal Blood glucose enters the cells via an insulin- independent glucose carrier. Glucose is metabolized by hexokinase which has a low Km (i.e., high affinity). (ii) Diabetes (i.e., circulating concentration of glucose is high) Intracellular concentration of glucose increases Aldose reductase [high Km (i.e., low affinity) for glucose] becomes active (polyol pathway) Production of sorbitol increases

cataracts

tyrosine

catecholamine precursor

1) Within the axon terminals of neurons (aka: synaptic boutons, presynaptic terminals) in the central and peripheral nervous system. Many neurons use dopamine and norepinephrine. Fewer neurons types use epinephrine. 2) In the chromaffin cells of the adrenal gland medulla. These cells release 80% epinephrine and 20% norepinephrine into circulation (only small amounts of dopamine.) When released, they primarily function as hormones.

catecholamine synthesis

Hyperlipidemia Hypertension Smoking Homocysteinemia Hemodynamic factors: shear force and turbulence Toxins (chemicals, lipopolysaccharide (LPS), etc.) Viruses and bacteria Immune reactions

chronic endothelial injury

composed of epithelium and stroma which contains capillaries. Ciliary epithelium, which covers the surface of the ciliary process, consists of two layers of epithelial cells: pigmented epithelial (PE) cells and nonpigmented epithelial (NPE) cells. Tight junctions between NPE cells form the anterior blood aqueous barrier. It excludes large molecules and maintains clarity of the aqueous humor.

ciliary process of aqueous humor

urine concentration Regulates: Urine volume via antidiuretic hormone

collecting tubule

"inability to see" (anopia)the first (prot-), second (deuter-), or third (trit-) Protanopia (mutations in the red opsin gene) Deuteranopia/Daltonism (mutations in the green opsin gene) Tritanopia (mutations in the blue opsin gene, least common) Red and green cone pigments encoded in X chromosome.

color blindness

3 million cones in human retina concentrated in the central retina in charge of color and acute vision

cone cells

The transparent part of the outermost layer of the eye Two primary functions (window & external lens) (i) Protection of underlying ocular structures from external environment (ii) Transmission (& refraction) of incident light

cornea

(Transparency) Less mitochondria Less respiration More anaerobic glycolysis

cornea and lens

CrP + ADP + H+ ↔ Cr + ATP Direction and rate of reaction controlled by ADP and ATP levels • Type II fibers have ~20% more CrP than Type I • Cr supplements most helpful in individuals who have the lowest initial levels (may help resynthesis) Clinical Note: 20% of the soluble protein in muscle is CK • Microtears in sarcolemma during exercise result in dramatic increases in blood CK

creatinine kinase

require the typical rise and fall of serum cardiac markers with at least one symptom of ischemia or ECG changes.

criteria for MI diagnosis

The major proteins in the lens (~90% of water-soluble proteins) α-, β- and γ-crystallins are molecular chaperones that function to help maintain lens proteins in their native, unaggregated states. Contribute to the transparency and refractive properties of the lens : Cold cataract γ-crystallin's solubility is sensitive to cold. Below a critical temperature, it precipitates forming "cold cataracts". Crystallins are sensitive to oxidation, osmolarity, and UV.

crystallins

due to phagocytosis of LDL and oxLDL by both macrophage and smooth muscle cells

development of fatty streaks

Albuminuria is characterized clinically as an early predictor for progression of diabetic glomerular nephropathy (DGN). • Advanced stage (4th stage/End Stage Renal Disease) of DGN is characterized by a loss of glomerular filtration.

diabetic glomerular nephropathy (DGN)

Cholesterolisfoundexclusivelyin animal products. Vegans, therefore, consume a cholesterol free diet. Cholesterolismostlyinthelean portions of meat. Limiting visible fat will not decrease cholesterol intake but it will lower saturated fat intake. Dietary cholesterol has a minor effect on plasma cholesterol. Elevated plasma cholesterol levels are generally a result of the factors listed on the previous slide. However,therearesomewaysto decrease plasma cholesterol through diet modifications. 13

dietary cholesterol

Solubledietaryfiberisfermentedbycolonicbacteria(the fermentation process and products provide energy for bacteria and favorably influences composition of gut microflora) Solublefiberalsoformsagel-likesubstanceandinterfereswith: - Absorption of dietary and biliary cholesterol- Reabsorption of bile salts TheDECREASEDreabsorptionofbilesaltswilldecreaseserum cholesterol by diverting more cholesterol into bile salt synthesis 3gofsolublefiber/daywilllowerserumcholesterolby~5 mg/dL Goodsourcesofsolubledietaryfiber:oatmeal,fruits,apples, oranges, and legumes (beans, lentils, peas, etc.)

dietary fiber

electrolyte reabsoption Secretes: K+, H+ ions under aldosterone control Corrects pH Reabsorbs: Na+

distal tubule

hypothesized result of superoxide radicals that escape from the CYP enzyme systems during drug metabolism, especially when coupled with the depletion of the antioxidant glutathione (GSH) (see slide 25, acetaminophen as an example).

drug-induced perivenous cell necrosis

deposited in the viscera, liver, skeletal muscle, pancreas, etc. and has high levels of DAGs and ceramides which inhibit insulin signaling promoting further insulin resistance

ectopic fat

Excess triacylglycerols start accumulating in the viscera -Lipids are stored in subcutaneous fat depots in lean individuals but as people become overweight or obese, adipocytes become insulin resistant with a limited capacity to expand and/or recruit preadipocytes.

ectopic fat deposition

Glucose uptake via GLUT4 translocation Glycogen is synthesized Glycolysis (PFK2 activated) ↓ FA oxidation due to ↑ malonyl CoA After high carb meal: • Blood glucose is the major source of energy • Lactate also contributes • As does FA but this is low

effect of increased insulin on cardiac muscle

handled in the same manner as xenobiotics. One example is bile salt synthesis from cholesterol Phase I involves the hydroxylation of the steroid nucleus catalyzed by cytochrome P450 enzymes such as cholesterol 7-α -hydroxylase Phase II is the conjugation of the bile acids with either glycine or taurine to form bile salts. Conjugated entities are excreted directly into the bile canaliculus

endogenous lipophilic compounds

increase oxidative metabolism capacity

endurance training goal

• Increase capillary network density, myoglobin content, cardiac output, mitochondria, LPL, FA transport and uptake • Increased intramuscular TAG (IMTG) content; Muscle hormone sensitive lipase activated by catecholamines, hydrolyzes IMTG • More quickly utilizes fat oxidation sparing muscle glycogen (sedentary and moderately trained individuals recruit more type II fibers during the first 30-minutes of exercise than an endurance trained individual)

endurance training will-

catechol-O-methyltransferase (COMT) & Monoamine oxidase (MAO)

enzymatically degrade catecholamines

1. Acetaldehyde: adduct formation 2. Increased ROS formation Alcohol metabolism results in an increased NADH/NAD+ ratio

ethanol metabolism steps

often considered in part due to a reduction in the efficiency of Monoamine Neurotransmission. Several first line antidepressant medications target monoamines. • 1) SSRI: Serotonin Selective Reuptake Inhibitors: Inhibit the selective reuptake of serotonin through its transporter • 2) MAOI: Monoamine Oxidase Inhibitors: Inhibit the enzymatic degradation of monoamines. • 3) Tricyclic Antidepressants: Blocks the reuptake of monoamines, as well as affecting cholinergic (acetylcholine) transmission.

etiologyofMajorDepressiveDisorder

↑ lipolysis

exercise ↑ epinephrine which-

Physiological, enzyme-catalyzed breakdown of fibrin clots

fibrinolysis

Italian study (GISSI Trial): 11,324 myocardial infarction survivors were randomized to one of 4 groups:1) 1 g/day fish oil (EPA & DHA) 2) 300 mg/day vitamin E 3) Both fish oil and vitamin E4) Placebo3.5 years later the groups consuming fish oil showed a 45% decrease in sudden death and a 35% decrease in death from CHD compared to placebo.(Vitamin E did not have a major effect.) Note: Sudden cardiac arrhythmic deaths account for 50% of all deaths due to heart disease.Omega-3 fatty acids decreased cardiac arrhythmia, heart rate, TAG, blood pressure, and thrombosis.Fish oil does not affect serum cholesterol.

fish oil supplements

Fish oils are a great source of the polyunsaturated long-chain, omega-3 fatty acids: EPA (20:5) and DHA (22:6) - Examples of fatty fish include: salmon, mackerel, anchovies, sardines, and herring (SMASH) Observational studies suggested that men who consumed one or more fatty fish meals per week had a 50% decreased risk of heart disease when compared to men who had <1 fish meal per month Diet and Reinfarction Trial (DART), a secondary prevention trial- 2,033 men randomized into three groups and received advice to: 1) reduce fat and replace saturated fat with polyunsaturated fat 2) consume two fatty fish meals/wk3) increase cereal fibers - Men in the group advised to increase fish consumption experienced a 29% reduction in MIs. No reduction in MIs was seen in the other two groups. - The study was prematurely halted because the benefits to the experimental group were so favorable.

fish oils

v With respect to metabolism:• In late fasting, ~50% of gluconeogenesis occurs in the kidney• The renal cortex expresses the enzymes of gluconeogenesis, including glucose 6-phosphatase v Maintenance of acid/base balance:• The kidney provides compensation for the acidosis that accompanies the increased production of ketone bodies v Retention of substances vital to the body:• Hydroxylation of inactive vitamin D forms into active form using enzymes produced in the kidney v Regulation of the water and electrolyte content of the body v Functions as a major endocrine organ: • Produces erythropoietin (EPO) • Produces 1,25-(OH)2 vitamin D3, the active form of vitamin D • Produces various autocrine and paracrine molecules such as prostaglandins, endothelins, and adrenomedulin • Produces and secrets renin from juxtaglomerular cells:• Renin is involved in renin-angiotensin system (RAS) which regulates blood pressure, sodium homeostasis and fluid balance• Catalyzes conversion of angiotensinogen into angiotensin I• Secretion is stimulated by decreased blood flow to the kidneys v Excretion of waste products and water-soluble toxic substances:• Urea is produced by the liver and then is transported in the blood to the kidneys for excretion in the urine. • Urine is formed as a result of a three-phase process • glomerular filtration• active and passive reabsorption• secretion

functions of kidneys

Metabolism of: Carbohydrates Amino acids Fats Energy homeostasis via: Glycogenolysis Gluconeogenesis Ketogenesis Repackaging excess FA Storage of: Glycogen Vitamin A Vitamin B12 Folate Iron Copper Purification, transformation & clearance of: ToxinsDrugsHormones Ammonia → urea Bilirubin Cholesterol Synthesis and secretion of: Lipids (VLDLs)Bile saltsAlbumin, plasma proteinsBlood clotting factorsAcute phase proteinsTransport proteins (apolipoproteins, transferrin, hormone binding proteins) Insulin-like growth factor-1 (IGF1) Glutathione

functions of liver

blood filtration Filters out: Low molecular weight, water- soluble compounds Conserves: RBCsMost proteins

glomerulus

an excitatory neurotransmitter: •results in the depolarization (more +) of the post-synaptic membrane -can lead to new gene expression through second messenger systems and transcription factors such as CREB.

glutamate

Additional transport mechanisms of glutamate OUT of the extracellular space and into cells is achieved by Na+ dependent symporters. These symporters leverage the high Na+ gradient across the membrane to transport other molecules against their concentration gradient. Glutamate can also transported into endothelial cells through additional Na+ dependent symporters ("A" or "N"), in addition to being recycled into astrocytes.

glutamate Na+ dependent symporters

permit entry of Na, K, Ca into the cell. This rapid depolarization can be toxic when prolonged. Therefore, glutamate removal must be swift because extracellular glutamate can be excitotoxic.

glutamate receptors

Glutamate is removed from the cleft via Na+ dependent symporters: Excitatory Amino Acid Transporters (EAAT)

glutamate removal

quickly tapped to produce ATP via glycolysis (anaerobic) Major source of ATP for middle distance races (400 to 5000 m) Slower than CrP but still very rapid compared to oxidative phosphorylation 2-3 times faster than aerobic metabolism but produces only ~8% as much ATP as "aerobic" glycolysis 3 ATPs vs 2 from blood glucose glycolysis Not sustainable over long time periods • H+ inhibits PFK1• Muscle glycogen in limited

glycogen use during exercsie

increase adipogenesis and insulin sensitivity decrease cell volume and inflammation

healthy white adipose tissue expansion

utilizes FAs for energy Heart has the higher levels of lipoprotein lipase (LPL) than either adipose or skeletal muscle increase uptake of FA into heart (from adipose, CM & VLDL) increase b-Oxidation (malonyl CoA low) PDHC inhibited by NADH and acetyl CoA from β-oxidation of FA and leads to decrease in glycolysis

heart during fasting state

Carbs: plasma glucose + muscle glycogen

heavy exercise fuel source

(1) Hp binds to free plasma Hb which allows degradative enzyme to gain access to the Hb. This prevents heme-protein induced Kidney nephrotoxicity (prevents renal damage). • When the concentration of Hb and Mb exceed the binding capacity of serum Hp, then the circulating Hb and/or Mb is filtered at the glomerulus. • Filtered Hb and Mb are nephrotoxic. (2) Hp prevents iron loss by conserving the iron in heme proteins.Macrophages take up and degrade the Hp-heme complex. Released iron is stored within the macrophage.

heme proteins with Haptoglobin

Anticoagulation: activates ATIII to bind & inactivate IXa, Xa, and IIa (thrombin). Prevents further fibrin clot formation in the near term (as bolus). acute

heparin mechanism of action and of the drugs used to treat/prevent heart attack.

encompasses an ovoid to diamond shaped region from two or more classic lobules divided into three zones Zone I is the most oxygenated (nearest the hepatic artery) Zone III is the least oxygenated (nearest the central vein which carries blood out of the liver).

hepatic acinus (acinus of Rappaport)

1. AMPK inhibits acetyl CoA carboxylase-2 (ACC- 2, muscle isoenzyme) lowering malonyl CoA 2. AMPK activates muscle malonyl CoA decarboxylase (MCoADC) decarboxylates malonyl CoA to acetyl CoA 3. Decreased malonyl CoA activates CPT-1

how AMPK helps facilitate FA oxidation during exercise

1. Exercise increases AMP levels 2. ↑ AMPK --> ↑ NO --> vasodilation --> up to 10-fold increase in muscle blood flow: more glucose, FAs, O2 available to exercising muscle 3. Insulin independent stimulation of GLUT4 insertion into sarcolemma

how AMPK induces GLUT4 translocation and vasodilation

Liver: During exercise, Cori cycle regenerates glucose from lactate via gluconeogenesis Muscle: Type I and cardiac muscles utilize lactate directly via TCA/ETC/OxPhos • Note: during recovery from sprinting, walking allows type I fibers to utilize lactate.

how lactate produced during exercise is used

Hyperammonemia (due to liver failure, urea cycle defect, etc) can disrupt glutamate/glutamine homeostasis leading to cerebral edema, disrupted neurotransmitter signaling, seizures, coma and death. NH3 crosses the BBB/endothelial cells readily and contributes to glutamate and glutamine synthesis via glutamate dehydrogenase (GDH) and glutamine synthetase (GS), respectively.

hyperammonemia

creatinine phosphate

immediate supply of atp during exercise

increases Depleting muscle glycogen increases glycogen resynthesis! Endurance partially dependent on pre-exercise glycogen stores

impact of training on muscle glycogen synthesis

• Normally, urea synthesis is more predominant than glutamine synthesis. • During acidosis, there is a decrease in urea synthesis and a proportional increase in glutamine synthesis ("Mop-up" function). • CPS-I (rate-limiting step in urea cycle) is inhibited by acid which results in less urea synthesis. • Ammoniagenesis is increased by 50% within 24 hrs of developing acidosis, because ketone bodies resulting from ketogenesis increases the acid load being excreted in the kidney.

increasing [H+] also activates ammoniagenesis in the PCT

• The further delineation of the medulla into outer and inner regions is based on differences in oxygen and mitochondria density which then limit pathways that can operate in these conditions. • Oxygen levels and mitochondrial density drop dramatically as one moves from the cortex to the inner medulla of the kidney. • Inner medulla is fairly anaerobic • Outer medulla is aerobic

inner and outer renal medulla

elevates fasting-blood glucose, triacylglycerol, blood pressure and lowers HDL-cholesterol, all of which increase risk of CVD and T2DM

insulin resistance

due to the near absence of the three irreversible enzymes of glycolysis: • Hexokinase (HK) • Phosphofructokinase 1 (PFK1) • Pyruvate kinase (PK) • The absence of glycolysis means that the proximal tubule is unable to catabolize glucose as a fuel during fed or fasting state. • Glycolytic pathway is present in the remainder of the nephron and collecting tubule. • Then, what will the PCT use as a fuel in the fed state? Fatty acids and glutamine

lack of glycolysis in the PCT

• • Composed mostly of H2O and proteins Primary function Transmission and focusing of light on the retina • Epithelial cells near the lens equator divide throughout life and continually differentiate into new lens fibers, so that older lens fibers are compressed into a central nucleus.

lens

a peptide adipokine (i.e. hormone) produced in white adipocytes Leptin levels are directly proportional to the amount of WAT Weight gain increases leptin levels Hypothalamus uses leptin levels to access adequacies of lipid storage. Higher leptin levels decrease food intake. (Leptin is known as a satiety hormone) Inhibits release of NPY and AgRP (orexigenic neurons) Stimulates release of MSH (anorexigenic) Increases T3 levels which can increase RMR Increases sympathetic tone (catecholamines and blood pressure) Leptin has a role in reproduction (onset of puberty & pregnancy require adequate levels of adipose tissue for success)

leptin

resultsindecreased MSH and increased release of NPY and AgRP which taken together act to increase appetite and decrease energy expenditure resulting in severe, early-onset obesity. MC-4 receptor deficiency is the most common form of monogenic obesity

leptin deficiency

Leptin feedback loop "fails" in the obese With leptin resistance, obese people do not have a decreased appetite, but they will remain hypertensive and have an increased RMR (energy expenditure) Leptin lacks "therapeutic potential" with respect to treating obesity because of leptin resistance Low-leptin levels are much more effective in preventing weight loss than high-leptin levels are at limiting weight gain Regaining weight following a diet isn't just a lack of "will power". Weight loss is more of an immediate threat to life than weight gain.

leptin resistance

fats

light exercise fuel source

- High total serum cholesterol >200mg/dL - Low HDL cholesterol <40 mg/dL

lipid modifiable risk factors for heart disease

increased ceramides, DAG + decreased GLUT2 --> impaired insulin secretion increased TAGs, ceramides, DAG, PKC activation --> decreased GLUT4 translocation, LPL increased ceramides, DAG, insulin resistance --> increased gluconeogenesis, VLDL production, HDL production

lipid overflow hypothesis

(Descending limb and ascending limb) Generates: Osmotic gradient (salt gradient)

loop of henle

Phagocytose LDL and oxidized LDL, becoming foam cells Produce growth factors and cytokines which draw smooth muscle cells into the intima

macrophage

It is hypothesized that the increase in CYP2E1 may also account for increased conversion of endogenous weak androgens into estrogens, resulting in the testicular atrophy and gynecomastia seen in some male alcoholic patients.

male alcoholic patients

Increased waist circumference (≥40 inches men, ≥35 inches women)

marker for insulin resistance

Metabolic syndrome is used as a screening tool to identify patients at increased risk for type 2 diabetes and cardiovascular disease. The presence of any three of the five risk factors in the table below constitutes a diagnosis of metabolic syndrome. (See Harmonizing the Metabolic Syndrome, Circulation 2009;120:1640-1645.) Metabolic syndrome increases the risk of heart disease, type 2 diabetes mellitus (T2DM) and stroke.

metabolic syndrome

Elevated waist circumference Impaired fasting glucose Elevated triacylglycerol Reduced HDL-cholesterol Elevated blood pressure

metabolic syndrome risk factors

Fats, and cholesterol in particular, cannot be absorbed from the diet unless they are incorporated into the mixed micelle. Stanols and sterols compete with cholesterol for incorporation into the mixed micelle.

mixed micelle

• Skeletal muscle only has enough ATP for 3 seconds of maximum muscle contraction • In one minute at rest, the heart will completely consume and replace all of its ATP a total of three times

muscle ATP reserves

increases with exercise intensity -Lactate levels reflect anaerobic glycolysis

muscle lactate during exercise

small peptides encoded by genes, between 3-36AA in length Endorphins, substance P, somatostatin, neuropeptide Y, angiotensin II, oxytocin, etc.

neuropeptides

chemical messengers that transmit signals across a synapse. This can be from neuron to neuron, or from neurons to cells in other tissues such as muscles or glands.

neurotransmitter

MI may still be progressing. An MI cannot be ruled out by troponin testing until several hours have passed since presentation (usually 6-9 hours, occasionally out to 12-24 hours) This is highly indicative of a progressing MI. The test values usually increase rapidly enough to "rule in" an evolving MI within 2-3 hours of presentation. CK-MB is often used similarly but is not as specific.

no elevation in cTnI upon admission? a repeated test at 6 hours shows a 4-fold increase in cTnI?

• Normally, urine contains negligible quantities of protein.• A small amount of albumin normally enter the filtrate (1-2g/day), but less than 1% of this filtered amount is excreted in the urine. • The molecular weight of albumin (69,000 Da) is just below the 75,000 Da cutoff of filtration barrier. • Albumin is highly negatively charged (pI = 4.9) which also cuts down on albumin filtration. (GAG is negatively charged)

normal protein in urine

PYY, GLP-1, CCK and Ghrelin are released into blood in response to presence or absence of intestinal nutrients and act peripherally on the vagus nerve and centrally in hypothalamus Distension of the stomach triggers vagus nerve to signal brain stem and nucleus tractus solitaries (NTS) satiety center

nucleus tractus solitaries satiety center

Nut consumption (≥5 times/week) lowers total blood cholesterol - One serving of nuts is ~1 oz (1⁄4 cup) and contains ~16 gm fat and 200 kcal. Although nuts have mono- and polyunsaturated fats, they lower cholesterol 25% more than what one would expect based on their fat content alone - Nuts are a great source of other nutrients including: protein, fiber (25% soluble), vitamins (E and folate), and minerals (Cu and Mg) - Almonds (64% of fat is oleic acid, 0.7% ω-3 fatty acid), Walnuts (21% oleic acid, 6% ω-3 fatty acid) - Flaxseed (pictured at right) has a high concentration of ω-3 fatty acid (slide 29)

nut consumption

adipose tissue is remodeled to accommodate adipocyte hypertrophy. Adipocyte hypertrophy is eventually constrained by the extracellular matrix and hypoxia resulting in adipocyte cell death and rupture.

obesity adipose tissue expansion

genetic predisposition sedentary activity high-energy foods over-utilization of fast food industry sugar intake (soft drinks) large meal size

obesity environmental factors

Obesity is usually due to the aggregate effect of many genes, each making small contributions, plus the environment ~70% of the variation in BMI is due to genetics Just a few cases of monogenic obesity (e.g. leptin deficiency)

obesity multifactorial

▪ Glutamate* ▪ Nitric Oxide ▪ Acetylcholine ▪ GABA ▪ Glycine

other common neurotransmitters

• Parkinson's Disease is a neurodegenerative disorder characterized by tremors, muscular rigidity and postural/gait abnormalities. • It is associated with a loss of the dopaminergic neurons of the substantia nigra. • Dopamine replacement is challenging because: • DA does not cross the BBB • The DA precursor, L-DOPA, is degraded by extracerebral DOPA decarboxylase or COMT, which can be degraded before it gets to the brain. • L-DOPA (levodopa) uptake is enhanced by the addition of drugs that block the degradation prior to brain uptake. L-DOPA is uptaken by LAT1, the L system transporter that enables AA entry into the brain.

parkinson's

rapid acceleration of glycolysis due to the sudden withdrawal of oxygen

pasteur effect

Oxygen/nutrient rich More mitochondria More beta-oxidation

periportal zone of liver

Oxygen poor Fewer mitochondria Less beta-oxidation, more FA synthesis

perivenous zone of liver

Peroxisomes are cellular organelles smaller than mitochondria and found in most tissues. They are abundant in hepatocytes and are a major site of oxygen utilization. They are self-replicating (similar to mitochondria), but do not contain DNA Peroxisomes contain many enzymes, most of which are involved in a variety of oxidation reactions Peroxisomes play a role in lipid metabolism (β-oxidation of very long chain FAs, α-oxidation of branched chain FAs), as well as chemical detoxification and alcohol metabolism.

peroxisomes

plant-based diet very low in saturatedfat and cholesterol which also contains soy protein, almonds, viscous (soluble, water-absorbing) fiber, and sterols/stanols, all of which have been shown to lower LDL-cholesterol.

portfolio diet

Because the human lens grows throughout life, the lens increases in thickness with age, and becomes less elastic. This leads to a loss of near vision, a normal condition known as presbyopia.

presbyobia

in the interscapular and supraclavicular regions in and amongst white adipocytes.

primary location of brown and beige adipocytes

cardiomyocyte necrosis and lysis, which allows intracellular molecules to leak into the circulation as serum cardiac markers. Since necrosis of the infarcted region has an abrupt onset and is usually completed after one day, the cardiac markers show a specific time-course of release. Thus, levels of serum cardiac markers are measured serially over several hours to days after patient presentation in order to confirm or rule out MI diagnosis and track its progress.

prolonged ischemia

also referred as albuminuria. • Proteinuria can be due to:• Excessive amount of protein presented to glomerulus• Defects in the slit diaphragm• Efficiency of proximal tubule reabsorption of filtered proteins • Proteinuria is a sign of chronic kidney disease, which can result from diabetes and diseases that cause inflammation in the kidneys.

proteinuria

Conserves: Most ions (Na+, K+, Cl-, HCO -) Glucose Amino acids Eliminates: Urea Creatinine 3 events, "R.A.G.": Reabsorption Ammoniagenesis Gluconeogenesis

proximal convoluted tubule

Fatty acids and glutamine

proximal tubule fuel preference

A short rest will... Allow CrP to recover exponentially, dependent on concentrations of ATP, ADP and Cr Lactate transported out of Type II to be used by Type I and cardiac muscle fibers

recovery of type II fibers

• Primary renal gluconeogenesis precursor is glutamine. • PEPCK (PEP carboxykinase) catalyzes the rate-limiting step in renal gluconeogenesis. • H+ ions and cortisol increase gene expression for PEPCK.

regulation of renal gluconeogenesis

• Kidney may not have glycolysis but does have lots of gluconeogenesis. • Renal gluconeogenesis occurs in the proximal convoluted tubule (PCT). • Renal gluconeogenesis accounts for 10-20% of glucose production during an overnight fast.• During an extended fast or an acidosis, ~40% of gluconeogenesis occurs in the kidney.

renal gluconeogenesis

resulting chain of events will lead to an increase in plasma volume, cardiac output and arterial pressure

retained sodium

(High demand for energy) More mitochondria More respiration Less anaerobic glycolysis

retina

• • A part of the central neuron system • A multi-layered and multi-cell-typed structure RetinaThe innermost layer of the eye consists of an outer pigmented epithelium and an inner layer containing light-sensitive neurons and photoreceptors. • Function To receive light that the lens has focused, convert the light into neural signals, and send these signals to the brain for visual recognition • Light enters the eye and passes the optic nerve fiber, ganglion neurons, bipolar cells, before it comes to the outer segment of photoreceptors The high metabolic requirements of the photoreceptors, which necessitate placing these cells next to their "private" blood supply (choroid = the vascular layer underneath the retina).

retina

100 million rods in human retina dominates the peripheral retina in charge of night and peripheral vision

rod cells

transmembrane protein composed of an apo-rhodopsin and 11-cis-retinal. Photoisomerization of 11-cis- retinal to all-trans-retinal leads to a conformational change in rhodopsin, thereby activating the rod phototransduction cascade.

rod cells, the photoreceptor is rhodopsin

1) Withintheaxonterminalsofneurons(aka:synapticboutons,presynapticterminals)inthecentraland peripheral nervous system. 2) In the enterochromaffin cells of the GI tract (90% of the total serotonin in the body.) Secreted serotonin acts on intestinal neurons (enteric nervous system) and affects intestinal motility and secretory functions. Some serotonin is absorbed into the blood and taken up by platelets, which can later release it to act as a vasoconstrictor, assisting with blood clotting.

serotonin synthesis

• ~90% of the glucose reabsorption in the PCT is mediated by the SGLT2 (sodium-glucose co-transporter 2), a low-affinity, high-capacity transporter. • SGLT2 is upregulated by high levels of its substrate, i.e., hyperglycemia. • If the quantity of filtered glucose exceeds the reabsorption capacity of SGLT2, glucose is lost in the urine ("glycosuria").

sodium-glucose co-transporter 2

Caloric intake does not decrease to compensate for an increase in sugary-beverage consumption Two groups of people were given 450 Calories of sugar/day for one month as either soft drinks or jellybeans Jellybean group compensated by eating less food and did not gain weight Soft drink group ate more food and gained weight On an empty stomach, beverages go directly to small intestine while jellybeans remain in the stomach Int J Obesity 2000;24:794 Average American has increased daily caloric intake by 137 Kcal/day due to soft drinks alone. In one year this could result in 14.2-pound weight gain

soft drinks

increase muscle mass

speed training goal

Avoiding the elevator Parking as far from the entrance as possible

sustainable decrease in positive energy balance

o In the past, repeated famines in the Southwest have removed lean individuals from the Pima Indian gene pool o Present day Pima Indians are descended from these famine survivors and are metabolically more efficient (gain more weight per Kcal consumed) than their lean counterparts

thrifty genotype

Pharmacological treatment of thrombotic disease with agents that accelerate physiological fibrinolysis.

thrombolysis

efers to the presynaptic, postsynaptic neuronal compartments, and the surrounding astrocyte. The tripartite synapse plays a critical role in maintaining glutamate-glutamine homeostasis by: Reuptaking excitatory neurotransmitters via Excitatory Amino Acid Transporters Converting glutamate to glutamine, a molecule that the brain can tolerate

tripartite synapse

Compounds that are both low- molecular weight and water-soluble are filtered from the blood at the glomerulus.

types of things filtered by glomerulus

Ultrafiltration (= the flow of water and water-soluble substances, limited by their size, across capillary endothelia) ∵ The capillaries in the stroma of the ciliary processes are highly permeable.

ultrafiltration of plasma (step one of formation of aqueous humor)

mediates BAT dissipates "excess" metabolic energy as"heat" UCP1 creates a leak in the mitochondrial proton gradient thereby uncoupling mitochondria (In uncoupled mitochondria, ATP production is not tied to electron flow. This results in less ATP production and more heat from metabolism)

uncoupling protein-1 (UCP1, aka thermogenin)

decrease adipogenesis, insulin sensitivity increase cell hypertrophy, low-grade inflammation, macrophage infiltration

unhealthy white adipose tissue expansion

Represents 3rd leading cause of cardiovascular-associated death(largelydueto pulmonaryembolism) Deep vein thrombosis (DVT) occurs most often in the large veins of the legs. Pulmonary embolism can result from DVT when part of the thrombus dislodges, travels to the lungs, and disrupts the blood flow of a pulmonary artery Referred to as "red clots", contain primarily fibrin with trapped RBCs

venous thrombosis

esponsible for packaging monoamines into vesicles

vesicular monoamine transporter (VMAT)

measureof visceral adipose tissue which is a visual indication of insulin resistance and by extension ectopic lipids and disease risk

waist circumference

Anticoagulation: interferes with recycling of Vit K (as co-factor for gamma glutamyl carboxylase); affects factors VII, IX, X, II. Reduces the efficiency of the coagulation cascade to prevent clotting over longer term. long term

warfarin mechanism of action and of the drugs used to treat/prevent heart attack.

which interferes with GLA residue synthesis, is still sometimes used for long- term therapy, although newer drugs with less bleeding risk are now available (Pradaxa (dabigatran), Eliquis (apixaban), etc., see appendix). Warfarin is still the drug of choice for patients with a mechanical heart valve. This drug is not generally used acutely because its effects depend on the replacement of existing circulating clotting factors. Thus, it takes several days to become fully effective. Frequent monitoring of a patient's PT/INR is necessary with warfarin therapy to maintain efficacy and prevent bleeding events.

warfarin therapy

A 10% loss in body weight will result in total serum cholesterol decreasing by ~12 mg/dL regardless of dietary fat intake WeightlossincreasesHDL- cholesterol ExerciseincreasesHDL-cholesterol levels and helps with weight reduction HigherHDL-cholesterolcorrelates with decreased risk of heart disease

weight loss effect on cholesterol

Deplete glycogen stores. Increase in glycogen stores cannot be attained without first depleting the stores by exercising to near exhaustion. Long, slow runs of marathon training (gradual build-up to ~20 - 22 miles) intended to increase cardiac output, myoglobin content, mitochondrial density, and capillary density will also deplete muscle glycogen stores. Eat high carb meals. Glycogen depletion activates glycogen synthesis, which can continue for several days (see figure). Taper the runs. Reducing the length of runs before the race (typically for 2 - 3 weeks) prevents glycogen depletion prior to race and allows time for recovery (e.g., to repair microtears originating from training).

what steps must Rose take to ensure that her glycogen stores are increased and remain high before the race?

specialized, loose connective tissue of epithelial cell origin containing white adipocytes (50%) and stromal-vascular cells (50%) (e.g. preadipocytes, macrophages, etc.) surrounded by extracellular matrix The white adipocyte has one large lipid droplet (unilocular) which pushes the nucleus and its few mitochondria to the edge of the cell Lipid droplet is surrounded by phospholipids and a protein scaffold called perilipin

white adipose tissue

Lipid storage, mobilization and distribution Hormone production Insulation Padding

white adipose tissue function

Today people consuming 250-300 Kcals/day more than in 1970s Other factors contributing to a positive-energy balance include lack of sleep (↑ ghrelin), poverty and stress (↑ visceral fat)

why obesity is higher though gene pool has not changed

abundant in neuronal membranes and are critical for normal brain development • Must come from diet and be BBB permeable • Cross the BBB through passive diffusion • Efflux from the brain is limited

ω-3 and ω-6 fatty acids polyunsaturated fatty acids (essential FAs) in the brain

(EPA and DHA) compete with ω-6 fatty acids for the same enzymatic apparatus but form a different series of products that are vasodilatory, non-thrombotic and anti-arrhythmic

ω-3 fatty acids

used to form prostaglandins that promote a vasoconstrictive, platelet pro-aggregatory, and pro-arrhythmic state

ω-6 fatty acids

Adiponectin levels increase as adipocytes become smaller. Adiponectin directly and indirectly increases insulin sensitivity Adiponectin activates AMPK which ↑ GLUT4 translocation and ↓ gluconeogenesis Adiponectin inhibits the conversion of M2 to M1 macrophages Adiponectin ↑ cellular ceramidase activity Adiponectin ↑ glucose-dependent insulin secretion

↑ Adiponectin How did weight loss bring about the change? How did weight loss bring about the change?

Weight loss occurs in visceral depots first. Lipids in the visceral depots (in and around pancreas, liver, heart, kidney, etc.) are the source of DAGs and ceramides (second messengers) that inhibit insulin action. Weight loss occurs in visceral depots first. Lipids in the visceral depots (in and around pancreas, liver, heart, kidney, etc.) are the source of DAGs and ceramides (second messengers) that inhibit insulin action.

↓ DAGs and ceramide How did weight loss bring about the change? How did weight loss bring about the change?

Weight loss will: 1) ↓ in rupture of adipocytes 2) ↑ Adiponectin which inhibits the conversion of M2 to M1 macrophages 3) Lean individuals have fewer macrophages and most of them are M2 rather than M1 Fewer M1 macrophages means less proinflammatory cytokines (TNF α etc.) to inhibit insulin action

↓ M1 macrophages How did weight loss bring about the change? How did weight loss bring about the change?