10/6&7: Blood Coagulation and Wound Repair

Protein S (Regulatory elements)

Acts as a cofactor of protein C; both proteins contain gla residues

Factor 1 (fibrinogen)

cleaved by thrombin to form fibrin clot

Aspirin (NSAID):

inhibitor of cyclooxygenase which catalyzes formation of prostaglandin E2 and other prostaglandins and leukotrienes.

PT time-

measure of how well coagulation system is doing. Because the way the test is done varies, they have developed the international normalized ratio (INR), which is a measure of the prothrombin time normalized, assesses cascade. Allows us to standardize tests.

Warfarin can deplete functional vitamin K reserves and therefore

reduce the synthesis of active clotting factors.

The extrinsic pathway is the response to

tissue injury

Although they are initiated by distinct mechanisms, the two pathways converge on a common pathway that leads to

to clot formation. It's a cascade

The hepatic synthesis of coagulation factors II, VII, IX, and X, as well as coagulation regulatory factors protein C and protein S, require the presence of

vitamin K

Glanzmann's thrombasthenia:

(GpIIb-IIIa def.) frequent nosebleeds (epistaxis), and may bleed from the gums. Red or purple spots on the skin caused by bleeding underneath the skin (petechiae) or swelling caused by bleeding within tissues (hematoma). Prolonged bleeding following injury, trauma, or surgery (including dental work). Affected women may have excessive blood loss during pregnancy and childbirth.

Bernard Soulier syndrome:

(GpIb def.) bruise easily and have an increased risk of nosebleeds (epistaxis). Abnormally heavy bleeding following minor injury or surgery or even without trauma (spontaneous bleeding). Tiny red or purple spots on the skin called petechiae. Women with Bernard-Soulier syndrome often have heavy or prolonged menstrual periods (menorrhagia).

Von Willebrand disease:

(VWF def.) easy bruising, long-lasting nosebleeds, and excessive bleeding or oozing following an injury, surgery, or dental work. Mild forms may become apparent only when abnormal bleeding occurs following surgery or serious injury.

Hemophilia A

-X linked recessive -decreased synthesis of factor VIII -treat with recombinant factor VIII

Hemophilia B

-X-linked recessive -Decreased synthesis of Factor IX -Christmas disease

Key concepts:

1) Blood coagulation system maintains and restores blood flow (homeostasis) even in the presence of injury 2) Blood platelets perform a critical function in preventing blood loss from the vasculature 3) Mutations can alter the function of platelets 4) Vitamin K is required for a functional blood coagulation system 5) Hereditary absence of blood coagulation factors can lead to excessive bleeding and hemorrhaging 6) Most blood coagulation proteins are synthesized in the liver so when you have liver problems, e.g., cirrhosis, this can lead to abnormalities of blood coagulation 7) Bleeding problems are quite common so this is something which affects the practice of dentistry 8) How do common drugs known as anti-coagulants work?

Clinical Applications:

1) Platelet transfusion 2) Transfusion with plasma or whole blood 3) Hereditary mutations which affects blood coagulation

ADP:

ADP is stored in dense bodies inside blood platelets and is released upon platelet activation. ADP interacts with a family of ADP receptors found on platelets (P2Y1, P2Y12, and P2X1), which leads to platelet activation. P2Y1 receptors initiate platelet aggregation and shape change as a result of interactions with ADP.

Clotting factor gene mutations: F7

Almost 300 mutations in the F7 gene have been found to cause a rare bleeding disorder called factor VII deficiency. This disorder commonly causes nosebleeds, easy bruising, bleeding of the gums, and prolonged or excessive bleeding following surgery or physical injury. In severe cases, life-threatening episodes of bleeding inside the skull or gastrointestinal tract can occur. Some affected individuals have no bleeding problems. The F7 gene mutations involved in this condition reduce the amount of coagulation factor VII in the bloodstream. A shortage of coagulation factor VII prevents blood from clotting normally, causing episodes of abnormal bleeding that can be severe. What determines the severity of the condition is unclear; it does not appear to be related to the amount of coagulation factor VII in the blood.

Prostacyclin: PGI2.

Anti-coagulant in its actions (it inhibits platelet activation and acts as a vasodilator). Prostacyclin is produced in endothelial cells, which line the walls of arteries and veins, from prostaglandin H2 (PGH2) by the action of the enzyme prostacyclin synthase. Prostacyclin, which has a half-life of 42 seconds, is broken down into 6-keto-PGF1, which is a much weaker vasodilator.

Clotting factor gene mutations: Factor V:

At least 100 mutations in the F5 gene have been found to cause a rare bleeding disorder called factor V deficiency. These mutations prevent the production of functional coagulation factor V or significantly reduce the amount of the protein in the bloodstream. People with this condition typically have less than 10 percent of normal levels of coagulation factor V in their blood; the most severely affected individuals have less than 1 percent. A reduced amount of functional factor V prevents blood from clotting normally, causing episodes of abnormal bleeding that can be severe. Factor V deficiency results from mutations in both copies of the F5 gene, although some people with a mutation in a single copy of the gene have mild bleeding problems.

Clotting factor gene mutations: F10

At least 130 mutations in the F10 gene have been found to cause a rare bleeding disorder called factor X deficiency. This disorder commonly causes nosebleeds, easy bruising, bleeding under the skin, bleeding of the gums, blood in the urine (hematuria), and prolonged or excessive bleeding following surgery or trauma. Some F10 gene mutations that cause factor X deficiency reduce the amount of coagulation factor X in the bloodstream, resulting in a form of the disorder called type I. Other F10 gene mutations result in the production of a coagulation factor X protein with impaired function, leading to type II factor X deficiency. Reduced quantity or function of coagulation factor X prevents blood from clotting normally, causing episodes of abnormal bleeding that can be severe.

Kallikrein Mutations

At least nine KLKB1 gene mutations have been identified in people with a blood condition called prekallikrein deficiency, which does not generally cause any health problems. The condition is usually discovered when blood tests are done for other reasons. The KLB1 gene mutations that cause this condition reduce or eliminate functional plasma kallikrein in the blood of affected individuals and likely impair the intrinsic coagulation pathway. Researchers suggest that this lack (deficiency) of functional plasma kallikrein protein does not generally cause any symptoms because another process called the extrinsic coagulation pathway (also known as the tissue factor pathway) can compensate for the impaired intrinsic coagulation pathway. Either pathway can activate proteins that are needed later in the clotting process. These individuals can survive fairly well even though it interferes with that event in the intrinsic pathway.

Cell-matrix adhesion receptor:

Cell membrane receptor by which cells specifically recognize cell matrix proteins and adhere to them. Fibronectin receptor is an example. Integrin receptors are more examples.

Flippase

Flippases (left) use ATP to move the aminophospholipids PS and, to a lesser extent, phosphatidylethanolamine (PE), from the outer leaflet to the inner leaflet of the PM against a concentration gradient

Floppases

Floppases (middle) use ATP to transport substrates such as phosphatidylcholine (PC), sphingolipid (SL) and cholesterol against concentration gradients in the opposite direction.

How can the effects of warfarin be neutralized?

Effects can be neutralized by massive dose of Vitamin K

How is warfarin administered?

Generally administered by tablet, but injectable formulations are available

Hemophilia A:

Hemophilia is a rare disorder in which your blood doesn't clot normally because it lacks sufficient blood-clotting proteins (clotting factors). If you have hemophilia, you may bleed for a longer time after an injury than you would if your blood clotted normally. Also called factor VIII (FVIII) deficiency or classic hemophilia, is a genetic disorder caused by missing or defective factor VIII, a clotting protein.

Heparin and Mast/basophils:

Heparin is a proteoglycan composed of a protein core and heparin glycosaminoglycan chains; the latter are sulfated oligosaccharide chains composed of repeating diassacharides of an amino sugar and glucuronic/iduronic acid. Heparin is stored in granules of basophils and mast cells.

Alpha2-anti-plasmin:

Inhibitor of plasmin which acts to limit (slow) the rate of plasmin action, e.g., the rate at which fibrin clots are degraded or removed. Hereditary absence of anti-plasmin can lead to hemorrhaging.

Schematic representation of mode of action of systemic (IV) and local (intra-arterial) administration of plasminogen activators (eg, tissue PA [TPA]) and plasmin.

Modified from Marder and Novokhatny.4 The top panel shows systemic (IV) administration, and the bottom panel shows local (catheter) administration of tissue-type plasminogen activator (t-PA; left) and plasmin (right), as typical representatives of direct and indirect fibrinolytic agents. PAI-1 indicates plasminogen activator inhibitor type 1.

Serum:

Liquid phase of clotted blood after spinning out clot.

Plasma:

Liquid phase of unclotted (anti-coagulated) blood (still contains clotting proteins). Cells have been centrifuged away.

Clotting factor gene mutations: F8 gene

Mutations in the F8 gene cause hemophilia A, the most common form of this bleeding disorder. More than 1,300 alterations in this gene have been identified. Some of these mutations change single DNA building blocks (base pairs) in the gene, while others delete or insert multiple base pairs. The most common mutation in people with severe hemophilia A is a rearrangement of genetic material called an inversion. This inversion involves a large segment of the F8 gene. Mutations in the F8 gene lead to the production of an abnormal version of coagulation factor VIII or reduce the amount of this protein. The altered or missing protein cannot participate effectively in the blood clotting process. As a result, blood clots cannot form properly in response to injury. These problems with blood clotting lead to excessive bleeding that can be difficult to control. Some mutations, such as the large inversion described above, almost completely eliminate the activity of coagulation factor VIII and result in severe hemophilia. Other mutations reduce but do not eliminate the protein's activity, resulting in mild or moderate hemophilia.

Thromboxane A2: TXA2

Pro-coagulant in its actions (acts as a vasoconstrictor) with short half-life (30 sec). Produced by activated platelets it stimulates activation of new platelets as well as increases platelet aggregation through increasing expression of the GPIIb/IIIa protein complex on platelet membranes. This same effect is also how ADP stimulates platelet activation. Clopidogrel blocks this action. Works by binding to thromboxane A2 receptors (G protein coupled receptor) on platelets. Synthesized by thromboxane-A synthase from prostaglandin H2 in a reaction which also produces equal amounts of 12-Hydroxyheptadecatrienoic acid (12-HHT).

Scramblases

Scramblases (right) are ATP independent and less substrate specific and facilitate the movement of lipids along concentration gradients.

Serotonin:

Serotonin or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Derived from tryptophan, serotonin is primarily found in the gastrointestinal tract (GI tract), blood platelets, and the central nervous system. Released upon degranulation of platelets at site of injury. Functions as a smooth muscle constrictor to immediately act to limit the loss of blood volume.

Anti-thrombin III:

Small serum/plasma protease inhibitor which is produced by the liver. Its activity is increased dramatically by binding to the anticoagulant drug heparin, which enhances the binding of antithrombin to factor IIa (Thrombin) and factor Xa.

Xarelto and pradaxa and warfarin are considered "blood thinners" What do they target?

Some of the other drugs that are out there target specifically other factors. By inhibiting these factors, even though the cascade starts, cant get past the factor that is being inhibited.

Enzymatic cascade:

Some physiological responses must happen quickly (like coagulation) so enzymes that catalyze those reactions need to be prepared but not active, for that reason a zymogen precursor form is synthesized and stays poised to act but requiring a rapid activation step. Coagulation is based on an enzymatic cascade involving sequential steps of limited proteolysis which activate and mature the structure of individual proteolytic enyzmes. In activating a small amount of initial catalyzing enzyme, this then leads progressively and rapidly to larger activated amounts of subsequently activated proteolytic enzymes ending up with a big amount of product (activated fibrin) required is form a clot and stop blood loss.

Relative activities of various medications:

Sometimes people are given fast acting agents in addition to warfarin. Gotta monitor INR frequently. If you have a patient that is taking Warfrin, you need to know their INR, becuase if you pull their tooth, they gonna bleed.

Summary

The body's ability to prevent fatal blood loss involves a complex symphony of many systems. Understanding how blood clotting occurs and can be manipulated clinically will be important to you as you practice dentistry. You will no doubt encounter many patients taking "blood thinners", for example, that will require careful attention and considerations in the management of their oral health.

Clotting factor gene mutations: Factor II:

The mutation that causes most cases of prothrombin thrombophilia changes one DNA building block (nucleotide) in the F2 gene. Specifically, it replaces the nucleotide guanine with the nucleotide adenine at position 20210 (written G20210A or 20210G>A). This mutation, which occurs in a region of the gene called the 3' untranslated region, causes the gene to be overactive and leads to the production of too much prothrombin. An abundance of prothrombin leads to more thrombin, which promotes the formation of blood clots. Also known deficiencies of prothrombin too.

EDTA (chelation of calcium):

chemical compound which sequesters calcium ion and draws it away from coagulation proteins. Acts as an anti-coagulant.

Vitamin K Mechanism and Warfarin

Warfarin as chemically synthesized is a receiving mix of R and S isomers. The S isomer form is most active at inhibiting reductase enzyme.

Warfarin:

Warfarin decreases blood clotting by blocking an enzyme called vitamin K epoxide reductase that acts to partially reactivate vitamin K after it participates in an oxidation reaction, e.g., carboxylase epoxidase.

Transfusions and blood products are used clinically:

Whole Blood Serum Platelets Factors Otherways to deal with clotting, transfusions and blood products. May get serum (no clotting factors), platelets, or even other factors.

ACD plasma:

acid-citrate-dextrose plasma.

What does vitamin K enzyme do?

adds carboxyl group to glutamyl residues. So Warfarin would stop that??

Transglutaminase (factor XIII):

an enzyme that catalyzes the formation of an covalent bond between a free amine group (e.g., protein- or peptide-bound lysine) and the acyl group at the end of the side chain of protein- bound glutamine. Fibrin is the physiological substrate for Factor XIII in blood coagulation. The reaction also produces a molecule of ammonia. Bonds formed by transglutaminase exhibit high resistance to proteolytic degradation (proteolysis)---thus stabilizing the fibrin clot to degradation

Platelets (thrombocytes):

anuclear cell bodies derived from megakaryocytes which circulate in the vasculature. Platelets undergo Adhesion, Activation, and Aggregation during coagulation.

Vitamin K:

at soluble vitamin needed as a co-factor by enzyme which catalyzes post-translational gamma-carboxylation (GLA residues) of coagulation proteins (Protein S, factors II, VII, IX, and X) and bone proteins matrix GLA protein and osteocalcin. These GLA residues represent calcium binding sites on these proteins.

Scott syndrome.

bleeding disorder caused by defective scrambling of membrane phospholipids. Scotts syndrome is failure to properly transfer phosphatidylserine to outer membrane. Necessary for binding of a lot of these factors that stick to these platelets. asymmetry builds up in membranes. Scott syndrome is a problem where we don't have phosphatidyl serine present to bind these factors.

Cell-cell adhesion receptor:

cell membrane receptor by which cells specifically recognize each other and adhere to each other. ICAM-1 receptor is an example.

Blood thinners:

drugs which inhibit blood coagulation and which are used to treat conditions where clinical conditions make if more likely to observe negative effects due to formation of clots (inadequate flow of blood, irregular heart rate, etc.). Examples, warfarin, xarelto, etc. Prolong bleeding time and can complicate dental surgery.

Tissue Collagen:

exposed collagen fibrils represent a site of platelet attachment to initiate blood coagulation.

Megakaryocytes:

normally 1/10,000 bone marrow cells are these large multi-lobulated nuclear cells which give rise to platelets. Number can rise dramatically in disease.

Gamma-carboxyglutamic acid:

post-translational modification of glutamic acid side chain of specific coagulation proteins which requires Vitamin K and which adds a calcium binding site needed for blood coagulation to proceed.

Queen Victoria - Hemophilia B

she was married to her cousin, and was a carrier. Lots of boys who have died at young age. No hemophilia in current family.

Gut bacteria:

site of metabolism of fat soluble vitamin K.

Vitamin K is an essential cofactor for

the synthesis of all of these vitamin K-dependent clotting factors.

Hemophilia

two forms, hemophilia A and B. Both X linked recessive. If you are male, and carry the gene, you are going to be effected. If you are female, and carry the gene, you will be a carrier, but the normal, you dont have the hemophilia linked disease. A vast majority of hemophilia diseases will be boys.

Kinetics of Platelet Aggregation

(AUDIO) AGGREGOMETER TRACINGS record the aggregation of platelets in platelet-rich plasma in response to an aggregating agent, in these cases collagen and two concentrations of ADP. The initial increase in light transmission is due to dilution by the agent, the small downward deflection to a change in platelet shape and the subsequent increase to aggregation. With collagen there is a lag before ADP is secreted by the platelets to cause aggregation; when ADP is supplied directly the effect is faster. The effect of a low concentration of ADP is reversed as enzymes destroy ADP.

Blood Clotting (Coagulation)

1) Damaged blood vessel leads to release of clotting factors. 2) Clotting factors convert prothrombin to thrombin 3) thrombin converts fibrinogen to fibrin 4) fibrin strands adhere to the plug to form an insoluble clot. -Dont forget the formation of the platelet plug and vasoconstriction

Blood Clotting (Coagulation) Process

1) Injury or Damage 2) Vessel Contracts 3) Platelet Plug 4) Fibrin Clot

Factor XIII

Activated by thrombin in presence of Ca2+; stabilizes fibrin clot by covalent cross-linking

Factor VIII (Cofactor)

Activated by thrombin; factor VIIIa is a cofactor in the activation of factor X by factor IXa

Factor V (Cofactor)

Activated by thrombin; factor Va is a cofactor in the activation of prothrombin by factor Xa

Factor II (prothrombin)

Activated on surface of activated platelets by prothrombinase complex

Factor X

Activated on surface of activated platelets by tenase complex and by factor VIIa in presence of tissue factor and Ca2+

Protein C (Regulatory elements)

Activated to protein Ca by thrombin bound to thrombomodulin; then degrades factors VIIIa and Va

A lot of these reactions are taking place on the surface of the cell membrane. Some of these factors, contain a modified glutamate residue, called ___________. This amino acid is natural high affinity binder of calcium ions, hence the designation of calcium as a co-factor in the schematic.

carboxyglutamate (Gla).

ADP and thromboxane A2

cause other platelets to become sticky and attach and undergo platelet release reaction -this continues until platelet plug is formed

Factor XII

Binds to exposed collagen at site of vessel wall injury, activated by high-MW kininogen and kallikrein

Common Pathway

Both pathways meet and finish the pathway of clot production in what is known as the common pathway. The common pathway involves factors I, II, V, and X.

How does citrate work as an anticoagulant?

Citrate and EDTA. Citrate, in the form of sodium citrate or acid-citrate-dextrose, is used to disrupt the coagulation cascade and prevent clotting. These citrate compounds bind to the calcium in the blood. By reducing the amount of calcium, there will be no regulation of the binding and the cascade cannot begin.

Citrate binds:

Citrate binds calcium ions ***There are a number of steps that require calcium in order for the reactions to occur

Wound Healing

Coagulation phase involves platelets and fibrin deposition, production of growth factors that stimulate migration into the wound site of neutrophils monocytes and macrophages, hence inflammation phase. Those cells release growth factors that trigger proliferation phase, where fibroblasts come in, collagen deposition, angiogenesis, .... finally they release growth factors that initiate remodeling phase where scar disappears.

Platelets Release Important Signaling Molecules upon Initial Binding to ______

Collagen;

Wound Healing

Complex process in which skin or other tissue repairs itself after injury.

Warfarin:

Discovered at U of W that cows that were eating hay that had allowed them to decay a little bit bled very easily. Discovered Warfarin. Patent for Warfarin generated so much for the university of Wisconsin, that they opened up a research institute. BILLIONZ.

What can interfere with the wound healing progression?

Disease states e.g., diabetes, venous or arterial disease, old age, and infection. When you get older, you dont heal as fast. Aging sucks.

Circulating fibrinogen binds

GP IIb/IIIa receptors on adjacent platelets, further strengthening the clot.

Fibrin Breakdown

In circulation, plasminogen adopts a closed, activation-resistant conformation. Upon binding to clots, or to the cell surface, plasminogen adopts an open form that can be converted into active plasmin by a variety of enzymes, including tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), kallikrein, and factor XII (Hageman factor). Fibrin is a cofactor for plasminogen activation by tissue plasminogen activator. Urokinase plasminogen activator receptor (uPAR) is a cofactor for plasminogen activation by urokinase plasminogen activator.

If you soak up all the calcium...

you won't initiate the clotting cascade

Primary Platelet Aggregation

Initial binding pf platelets to vWF is mediated by glycoproteins that are necessary for platelet tethering, but do not promote strong adhesion. Firm adhesion of platelets to the subendothelia is mediated by a glycoprotein called GPIIb/IIIa.

Antithrombin III (Regulatory elements)

Most important coagulation inhibitor, controls activities of thrombin, and factors IXa, Xa, XIa and XIIa

Fibrin Polymerisation and lysis:

Pathway of fibrin polymerisation and breakdown. The knobs on the E domain bind to the holes on up to four D domains (grey lines), forming a long, fibrous latticework. The clot is then stabilised through cross-linking. The clot can be degraded, yielding different degradation products if it has been cross-linked.

Where are the coagulation factors in the PRP tube?

Plasma contains all the coagulation factor

The process just described is called a

Platelet plug

Platelet Release Reaction

Platelets that stick to collagen undergo a release reaction, in which they secrete ADP, serotonin, and thromboxane A2. Serotonin and thromboxane A2 cause vasoconstriction. ADP and thromboxane A2 attract other platelets and make them stick to the growing mass of platelets that are stuck to the collagen in the broken vessel this process is called a platelet plug. Shown in the picture above.

Intrinsic Pathway (clotting cascade)

The intrinsic pathway is activated by trauma inside the vascular system, and is activated by platelets, exposed endothelium, chemicals, or collagen. This pathway is slower than the extrinsic pathway, but more important. It involves factors XII, XI, IX, VIII.

Why do we have the fibrin mesh?

The platelet plug the initially forms is not strong enough by itself to fully prevent further bleeding. A fibrin mesh is laid down to further reinforce and strengthen the platelet plug.

the international normalized ratio (INR) is calculated from

a PT result and is used to monitor how well the blood-thinning medication (anticoagulant) warfarin (Coumadin®) is working to prevent blood coagulation.

A prothrombin time (PT) is a test used to help detect and diagnose:

a bleeding disorder or excessive clotting disorder;

prothrombin time

a measure of the integrity of the extrinsic and final common pathways of the coagulation cascade. This consists of tissue factor and factors VII, II (prothrombin), V, X, and fibrinogen.

the intrinsic pathway is the response to

an abnormal vessel wall

Proliferative phase:

angiogenesis, collagen deposition, granulation tissue formation, epithelialization, and wound contraction.

Inflammatory phase:

bacteria and debris are phagocytosed and removed from the wound site. Factors are released that cause migration and division of cells involved in the proliferative phase.

Secondary hemostasis:

clotting cascade. Consists of the cascade of coagulation serine proteases that culminates in cleavage of soluble fibrinogen by thrombin. Thrombin cleavage generates insoluble fibrin that forms a crosslinked fibrin mesh at the site of an injury. Fibrin generation occurs simultaneously to platelet aggregation.

Remodeling phase:

collagen is remodeled and realigned along tension force lines and cells no longer needed are removed by apoptosis.

It is this complex of calcium with the Gla-factors that allow specific interactions with acidic membrane lipids that ultimately lead to the

correct tertiary and quaternary protein structures recognized by other proteins in the pathway.

Where is ADP and serotonin stored in platelets?

dense granules

Fibronectin

distinct and independent functions during tissue repair Functions of plasma and cellular fibronectin (FN) during wound healing. The different forms of FN play distinct roles during the different stages of wound healing.

Transglutaminase (factor XIII) reaction

factor XIIIa indicates the enzyme has been activated

Wound Healing

hemostasis- formation of platelet plug; fibrin clot Inflammation- involves neutrophils and macrophages that are phagocytose bacteria. Proliferation-Fibroblasts and microfibroblasts trying to fill in and prepare structure. Angiogenesis. Remodeling- Collagen fibers get remodeled and you heal

Platelet aggregation is achieved by

mediating expression of the glycoprotein complex GP IIb/IIIa in the cell membrane of platelets.

ADP and thromboxane A2 attract.... and make them stick to....

other platelets; the growing mass of platelets that are stuck to the collagen in the broken vessel.

Clotting Process: Blood Vessel Spasm

platelets secrete serotonin which causes blood vessels to spasm, decreasing blood flow to that area

The PT is usually measured in

seconds and is compared to a normal range that reflects PT values in healthy individuals. Because the reagents used to perform the PT test vary from one laboratory to another and even within the same laboratory over time, the normal ranges also will fluctuate. To standardize results across different laboratories in the U.S. and the world, a World Health Organization (WHO) committee developed and recommended the use of the Internationalized Normalized Ratio (INR),

Other types of tubes generate _______, in ______ tubes, we are allowing clot to form. Clear solution on top is the something of those clotting factors.

serum; serum

Fibrinogen is _____, fibrin when it is generated by thrombin cleavage is _____, forms fibrin crosslink at sight of injury

soluble; insoluble

Serotonin and thrombonxane A2:

stimulate vasoconstriction, reducing blood flow to wound

Prothrombin Test:

take citrated plasma and add calcium back and also thromboplastin (combination of phospholipids and tissue factor) Evaluates presence of prothrombin (II), factors X, V, and VII and fibrinogen [intrinsic and common pathway components]

Prothrombin test (PT)-

tests persons ability to clot by evaluating presence of shit above. You take citrated plasma, and you add back calcium.

When the INR is higher than the recommended range, it means...

that your blood clots more slowly than desired, and a lower INR means your blood clots more quickly than desired.

Two pathways lead to the formation of a fibrin clot:

the intrinsic and the extrinsic pathway

Crosslinking of fibrin is catalyzed by

transglutaminase or Factor XIII E domain cross-links to a D domain

Important to appreciate when you do a blood draw from an individual, depending on the type of blood tube, you will generate:

two different types of material.

Serotonin and thromboxane A2 cause ________.

vasoconstriction

Primary hemostasis:

vasoconstriction and platelet response. Platelet aggregation at the site of injury is mediated by platelet receptors, platelet-derived agonists, platelet-derived adhesive proteins and plasma-derived adhesive proteins.

von Willebrand factor (Regulatory elements)

von Willebrand factor

Hemostasis:

within minutes post-injury, platelets aggregate at the injury site to form a fibrin clot which acts to control bleeding.

Vitamin K- Carboxyglutamate

without Vitamin K, you cant form active proteins, and you will end up with a poor clotting mechanism

Platelets that stick to collagen undergo a release reaction, in which they secrete _____, ___, ______.

ADP, serotonin, and thromboxane A2;

What is ACD anticoagulant?

Acid Citrate Dextrose Solution (sometimes called Anticoagulant Citrate Dextrose Solution) is a solution of citric acid, sodium citrate and dextrose in water.

Factor XI

Activated by factor XIIa

Factor IX

Activated by factor XIa in presence of Ca2+

The classic model of wound healing can be divided into four sequential overlapping phases:

1. hemostasis, 2. inflammatory; 3. proliferative; 4. remodeling.

In healthy people an INR of ___ or below is considered normal. An INR range of ___ to ___ is generally an effective therapeutic range for people taking warfarin for disorders such as atrial fibrillation or a blood clot in the leg or lung. In certain situations, such as having a mechanical heart valve, you might need a slightly _____ INR.

1.1; 2.0 to 3.0; higher

Factor VII

Activated by thrombin in presence of Ca2+

Function of PGI2

Prostacyclin (PGI2) chiefly prevents formation of the platelet plug involved in primary hemostasis (a part of blood clot formation). It does this by inhibiting platelet activation.[3] It is also an effective vasodilator. Prostacyclin's interactions in contrast to thromboxane (TXA2), another eicosanoid, strongly suggest a mechanism of cardiovascular homeostasis between the two hormones in relation to vascular damage.

Thrombomodulin (Regulatory elements)

Protein on the surface of endothelial cells; binds thrombin, which then activates protein C

PRP tube contents

RBC's packing at bottom, layer of WBC's (buffy coat), and then plasma on top of that.

Factor IIITissue factor (Cofactor)

Subendothelial cell-surface glycoprotein that acts as a cofactor for factor VII

Intrinsic, extrinsic pathways diagram

The coagulation factors are generally serine proteases, which act by cleaving downstream proteins. The exceptions are tissue factor, FV, FVIII, FXIII.[8] Tissue factor, FV and FVIII are glycoproteins, and Factor XIII is a transglutaminase. The coagulation factors circulate as inactive zymogens. The coagulation cascade is therefore classically divided into three pathways. The intrinsic and extrinsic pathways both activate the "final common pathway" of factor X, thrombin and fibrin.[9] Write out and understand this pathway.

Extrinsic Pathway (clotting cascade)

The extrinsic pathway is activated by external trauma that causes blood to escape from the vascular system. This pathway is quicker than the intrinsic pathway. It involves factor VII.

Schematic representation of the cellular mechanisms that pattern wound healing

The four main phases of wound healing are hemostasis, inflammation, proliferation, and remodeling. Different cell types are involved in regulating biomechanical and biochemical functions during these phases of wound healing. The main source for these cell types are different stem cell niches. Hematopoietic stem cells (HSCs), platelets, neutrophils, and monocytes regulate hemostasis and inflammation. Mesenchymal stem cells (MSCs), endothelial progenitor cells (EPCs), pericytes, vascular smooth muscle cells (VSMCs), endothelial cells (ECs), and fibroblasts regulate angiogenesis. Epithelial mesenchymal transitions (EMT), fibroblasts and fibrocytes regulate collagen, and extracellular matrix (ECM) production. Epidermal stem cells (ESCs) and keratinocytes regulate epithelialization. Fibroblasts and proteolytic enzymes regulate remodeling in the final phase of wound healing.

International Normalized Ratio (INR)

This ratio — which allows for easier comparisons of test results from different laboratories — is used if you take blood-thinning medications.

Role of A2 in platelet aggregation

Thromboxane A2 (TXA2), produced by activated platelets, has prothrombotic properties, stimulating activation of new platelets as well as increasing platelet aggregation.

Serotonin Biosynthesis

Tryptophan -> 5-HTP -> 5-HT

Fat Soluble Vitamins

Vitamin D Vitamin E Vitamin A Vitamin K

Warfarin (Coumadin)

Warfarin competitively inhibits the vitamin K epoxide reductase complex 1 (VKORC1), which is an essential enzyme for activating the vitamin K available in the body

Drugs that prevent blood coagulation, (e.g., "blood thinners")

Warfarin, Pradaxa, Xarelto, Eliquis, and Plavix