Cystic Fibrosis: Pathophysiology and Therapies

what is the key pathology of CF lung disease? is this pathology obstructive or restrictive?

CF ends in *bronchiectasis (obstructive lung disease)* the airway is so damaged that it can't effectively clear anything big thick dilated airways which are much larger than you should normally see. these are fully of pus. in the clinic we will see an obstructive lung pattern. FVL looks at how fast and how much air you can blow out from the top of a full breath. normally you're supposed to have a nice looking pattern. if you have CF there's airway obstruction. you can start out pretty fast but quickly you slow down. how much air and how rapidly you can clear it from your lungs is greatly reduced. that's characteristic of an obstructive lung disease

what is the combination of antibiotics usually used for pseudomonas?

# of antibiotics that are used orally TMP/sulfa is more for staph Minocycline for more rare gram negative rods Azithromycin has anti-inflammatory effects, may have some capacity to kill biofilm PsA the antibiotics that really work for pseudomonas are the FQs (cipro and levo) aerosolized antibiotics - tobramycin (anti-gram negative, used in serious infections), aztreonam (monobactam), other antibiotics b-lactams AGs when we're doing antibiotics we will usually double up with a *combination of a b-lactam and an aminoglycoside (or FQ). this reduces the emergence of resistance*

in addition to killing bacteria, IV antibiotics also also reduce what? what can you use to track this change?

*when we use IV antibiotics, in addition to killing bacteria it also reduces inflammation* less bacteria = less inflammation this study looked at impact on IV antibiotics on bacterial load and inflammatory markers in patients >6 from beginning to end of tx, things went down roughly 0.5 log. % neutrophils also reduced post tx these numbers are still pretty high

CF - AD or AR? which 2 organs affected by CF are most important? what organ serves as the primary means of dx?

AR, affects about 33,000 in use (it's growing as patients are living longer) 70,1000-100,000 worldwide, prob underestimated manifestions involve a number of different organisms. *most relevant are pulmonary* (pulmonary failure is leading cause of death) and *pancreas* (panc insufficiency - begins at birth and requires that they take enzyme replacement therapy for life to digest & absorb nutrients). *sweat gland involved in almost all patients and is primary means of dx*

video

normal: -yellow and green dots are Na+ and Cl- -up above is where the mucous lives -CFTR is transporting Cl (prob also HCO3-) which is helping to maintain normal hydration. Na+ is also moving in an appropriately regulated fashion CF: -mucous is accumulating on top of the airways -CFTR is no longer able to transport Cl -Na+ tends to be over absorbed

Burkholderia cepacia what is the clinical significance of this organism? (2) even though this organism has a low colonization rate, why is it a big problem? can these patients get a lung transplant?

not very common but can be very deadly in some patients it's not such 1 organism - it has 11 defined genomovars clinical significance: 1. *very resistant to antibiotics, in some patients it can lead to rapid decline and death in 6-8 weeks* 2. on average, *patients who are infected have about 9-10 years shorter survival* -can be transmissible (CF summer camps had outbreaks) -colonization rate is low but you *want to avoid it bc tx options are limited*. if patients do progress to advance disease and lung transplant, they *won't transplant them bc of the potential for infection afterwards*

CF therapies and burden of care

one of our big goals to *make sure we are getting the most beneficial treatments for patients*

azithromycin also improved what 3 things?

risk of exacerbation more rapidly you drop, the more severe and more frequent you have exacerbations 1. 40-50% reduction in exacerbation frequency 2. 47% reduction in hospital days 3. 39% reduction in IV antibiotics

what inc the viscosity of the mucous in CF? how does the pressure change in the mucous? what causes mucus buildup? what causes mucous dehydration?

some of these properties can be seen in other disorders such as COPD normal airway: cilia are fully extended, there's a nice mucous layer (gel layer) which can be moved CF airway: mucous layer has been expanded and is full of gunk. we have extracellular DNA that comes from neutrophils. there are cells which have died. this inc the oncotic pressure in the mucous. recent evidence indicates as the mucous is being released by the submucosal glands doesn't release normally. may have to do with HCO3- transport. all of this leads to a very thick, sticky, and poorly mobile mucous blanket. this may be what starts the process of CF

EBM success in CF - 6 interventions

steady improvement in outcomes of CF. along with this has been the development of therapies that tx CF. 1. PERT (pancreatic enzyme replacement therapy) 2. dornase alpha (human recombinant DNAs) 3. ibuprofen/azithromycin - anti-inflammatories 4. inhaled antibiotics 5. hypertonic saline helps to hydrate mucous 6. drugs that work on CFTR

6 steps from CFTR gene to CFTR protein where can you have a problem

steps: 1. genes are in the nucleus and are transcribed into mRNA 2. mRNA translated into proteins in the ER 3. folding proteins bind to help them get into the right shape 4. in the golgi, glycosyl groups are added (particularly in CF) (process of *maturation*) - not sure if this is 100% right 5. protein exo/endocytosis 6. transport up to the cell membrane and protein recycling occurs *you can have a problem anywhere in this path with CF* 1. can have a problem with the early steps in making enough mRNA 2. in the biosynthesis of any protein 3. folding of the protein 4. maturation of the protein 5. how well it works once it gets to the cell membrane those difference places that you have problems are ways people categorize CFTR mutations

what are 4 beneficial factors of using newborn screening for CF? what do they have a risk of?

studies have indicated that patients identified with NBS: 1. improved growth 2. improved cognitive function 3. less time to dx (typically meeting with patient's family when they're 2-3 weeks, before they have any pulmonary symptoms) 4. reduced catastrophic hospitalization costs. 5. risks of early PsA colonization - by just using good uniform, infection control policies in the clinic that's not really an issue universal in US

CF: recent advances

sweat test through the years *we have been adding systematic therapies that have lead to advances and inc longevity*, starting with improved means to getting mucus out of lungs (underlying problem of CF) giving panc enzyme use of antibiotics that are used to target the pathogens found in CF - pseudomonas importance of high cal diet Cl transport in the sweat ducts was not working in patients with CF - first inkling that there was a salt transport problem leading to disease manifestations CFTR therapies historically really targeted the downstream symptoms and have advanced to therapies to tx the cause

summary

there are numerous downstream therapies that have helps to improve CF outcomes over last 20-30 years with modulators we have become to change face of CF care staying well takes a lot of work important to understand why the patient is not adhering

what effect does azithromycin have on lung function?

they found there was significant improvement in lung function in azithromycin compared with placebo *5-6% improvement in lung function*

what are the channel factors that influence CFTR's anion transport? (3)

things we can target to make it work better - make more channels (N), target who much time each channel spends open (open channel probability - Po), we can target how big the channel is (conductance) N x Po x G = total Cl- transport drugs that are being developed are helping the channel stay open more or helping us get more channels to the cell membrane.

what is a potential sequela of having mucoid pseudomonas i.e. why do we care about it?

this is looking at lung function in patients with different types of bacterial infections. on the left side is % predicted FEV1. people with nonmucoid PSA+ = pretty steady lung function over 6-8 yrs PsA - *with mucoid PsA, there's a clear reduction in lung function in CF patients as opposed to those with non-mucoid*. once it's chronically there it's very hard to tx

Traffic and Transport drug trials

traffic & transport enrolled 1100 patients who had 2 copies of F508, tested 2 doses of lumacaftor (VX809) + ivacaftor vs. placebo 2 diff dose groups: one was 400 mg 2x daily, one was 600 mg 1x daily. placebo had a more rapid onset of an exacerbation. this lead to approval of this drug with 2 copies of F508

approaches to adherence - unwitting, erratic, intelligent

unwitting - re-education and reinforcement erratic - reminders on phone, linking taking their therapies to doing other things (take your pills when you brush your teeth), prioritize intelligent - deeper understanding of choices

cycle of CF and drug interventions

we lose CFTR, we alter Cl, HCO3-, and Na+ transport we begin a process of thick mucous, infection, inflammation, and damage. that ends up with bronchiectasis we have lots of therapies that address a lot of these places - most recent = CFTR modulators (drugs that help CFTR work if it's mutated). there are drugs that hydrate mucous, drugs that help break up the mucous, antimicrobials, anti-inflammatories

correcting F508del CFTR

western blot - looks at CFTR protein. normally CFTR is a wide, smearing looking band around 180 Kd. it's smearing because it's fully glycosylated, it's heavier, and runs slower on a gel deltaF508 gets stuck at a lower MW, it doesn't get smeary because it doesn't have those glycosylation steps that happen later. you can separate these 2 pretty easily *strategy = inc N* *deltaF508 expresses cells with inc concentrations of VX809*. 1st you see the immature band and as you get to higher concentrations you start to see the emergence of a darker band and that tells us we are making mature F508, it gets past that sticking point. if you get to really high conc, the cells don't like it *when you look at the functionally, as you inc dose of VX809 you start to see inc % of WT activity*. it tops out at about 15%, it's better but a long way from norma. about 15% of normal

EM appearance of CFTR

when CFTR is working you have happy cilia when CFTR does not work, the *cilia are smushed and can't clear mucous out*. CF starts with mucous that fails to be cleared

what is a big problem with CF treatment? unwitting, erratic, intelligment

*adherence is a huge issue * 50-60% of prescribed is taken, can be as low as 30% for inhaled medications and chest clearance adherence broken down in 3 ways -unwitting - mistakenly feel they are adherent -erratic - they get it but can't stay on top of it (too much going on, not a high priority) -intelligent - actively choose not to. that's a big challenge

mechanisms that contribute to antimicrobial resistance in pseudomonas resistance mechanisms occur after exposure to what? what are 3 resistance mechanisms?

*an acute exposure to a beta lactam can result in resistance mechanisms* 1. *down regulated porins* - b-lactams can't get in 2. *unregulated pumps* - get the b-lactams out 3. *b-lactamase* - breaks down b-lactams

most common CF causing mutation

*deltaF = most common CF causing mutation* -at least one copy found in at least 90% of patients WT cell shows where CFTR belongs, right at the cell membrane *deltaF is missing CFTR at the cell membrane in CF patients* -deltaF is stuck in different compartments (ER, proteasome --> little makes it up to the cell membrane)

what is the purpose of EPIC? what did the EPIC study determine? what is the standard of care to tx pseudomonas infections w/ tobramycin in CF children?

*designed to examine best means to eradicate early PsA infection in children with CF* when patients have an early PsA infection, we can intervene to get rid of it about 90% of time study compared 2 approaches: 1. *culture based tx* - every time you got a culture you got treated 2. *cycle based tx* - once you have a + culture you then went on to every other month therapy whether or not we ever picked up PsA again the 2 groups were subgrouped into just tobramycin or tobramycin + cipro they found it made no difference. it worked about the same. *standard of care is to use inhaled tobramycin for 1 month which will reduce detection of PsA to <10%*

high throughput screening

*high throughput screening* - uses systematic and reproducible best, they test all the compounds that make CFTR work, they find the ones that work and then they work backwards, how they work and why they work and make drugs this has lead to many drugs in clinical trials or has recently been approved by the FDA by a company called Vertex

CF survival by birth cohort

*lung function by birth cohort continues to improve* as patients are being born, they're having better and better lung function at the time we begin they're therapy. but it still goes down

median age of death in a given year with CF? what is the distribution of age of survival?

*median age of death in a given year with CF --> mid 20s* *bimodel component of survival* --> there are patients who do well and are long living and there is a minority of patients who don't do well (primarily in adolescence)

Potentiating G551D CFTR (VX-770)

*most successful * targets a *CFTR gating mutation (G551D)*. there's a substitution at this point which gets in the way of the gating channel *3rd most common but only 5% of patients have this* -higher in Ireland -channel doesn't open correctly --> this drug helps open CFTR this looks at airway cells from a patient with G551D mutation. stimulate with cAMP and looking for upswing of current/Cl transport. when you add more and more of VX770 you get more and more activity of CFTR, at the end they added a blocker for CFTR

what is the significance of mucoid produced by pseudomonas? what the presence of mucoid indicate? biofilms - what is the role of the bacteria on the outside vs. the inside? how do biofilms compare to mucoid?

*mucoid* = mucous / carbohydrate makes it *very hard for antibiotics to penetrate*. this is a *marker for chronic infection*. mucoid is a change that is very persistent, takes a long time to happen, and when it happens it *doesn't typically change back* *biofilm growth* = when bacteria adhere to a surface & grow. bacteria swim around, stick, start to *grow as an organized colony*. as the colony grows, the bacteria have difference roles: -*outside bacteria* get nutrients and feed the bacteria on the inside -*inside bacteria* are less metabolically active which makes them more difficult to kill -in CF you get biofilm growth in the mucous. *biofilms are dynamic & come and go - have to have the right conditions for it to happen*

how is survival changing for CF?

*survival is going up* *in 2015 there are more adults than children with CF* historically more of a pediatric disorder

CFTR what is it and how is it unique? what are 3 components of CFTR?

*traffic ATPase --> unique bc it's the only one that's a channel*. CFTR is the only one that transports Cl and functions as a channel (Cl, HCO3-, etc) other examples: chemotherapy resistance due up regulation of p-glycoprotein which pumps chemo out of cells (relative of CFTR). adrenal leukodystrophy is caused by a protein that's a relative of CFTR. sulfanourea receptor is traffic ATPase 1. *2 TMDs* = anchor the protein in the cell membranes 2. *2 NBDs* = bind to each other & w/ ATP to hydrolyze it which helps to open and close the channel 3. *R domain* = allows regulating by cAMP and phosphorylation

azithromycin has what additional property in addition to being an antibiotic? in what phase can it kill pseudomonas?

*unique anti-inflammatory properties at lower doses*. helps change the macrophages so that they clean up problems rather than driving more inflammation *may kill pseudomonas if it's growing in the stationary phase* 185 patients with CF randomized to placebo or active drug. all PsA+. had beginning to moderate lung disease. treated for 24 weeks

what are 3 chronic conditions associated with CF?

1. *CF related diabetes* -found in ~1/3 of patients -as patients get older, the risk goes up -as time passes, the islet cells become dysfunctional (debate if it's caused by inflammation or if there's CFTR in islet cells) with progression to glucose intolerance and CFRD. -*tends to be a marker for more severe disease* -hard to tx - very unusual to cause something like DKA. can get long term detriment such as kidney problems, periphery neuropathies, eye disease 2. *depression* 3. *bone disease* -problem that becomes more problematic as patients get older -relates to vit D problems, as patients get thinner/cachetic, less weight bearing -advanced bone disease can get in the way of lung transplant

what are the 2 problems that contribute to the folding defect in F508del? why is it important clinically that there are 2 steps?

1. *co-translational folding of NBD-1* -when the nascent polypeptide comes out, the 1st thing it's supposed to do is fold into a nice tight NBD1. this doesn't work very well 2. *domain assembly* - NBD1 is supposed to interact with another part of the protein and doesn't do that very well. there's at least 2 folding problems. *this is important bc prob 1 drug that tries to normalize folding will not be enough --> have to probe use several drugs to affect the folding steps*

what are 4 other key aspects of CF care and how do you tx them?

1. *nutrition* -90% have panc insufficiency -patients who are thin typically don't do well. goal is get BMI to 50th percentile or higher -not unusual for diabetes to develop, -tx: *enzymes, calorie supplements, insulin* (growth hormone in addition to being management for diabetes) 2. *fat soluble vitamin def* -don't absorb fats very well. fat soluble vitamins are also anti-inflammatory -tx: *fat soluble vitamin supplements* 3. *liver disease (cirrhosis)* is clinically relevant in 5-10% -tx: bile acid flow agents, may need liver transplant 4. *male infertility due to blockage of vas def*. they make sperm, they just can't get it where it needs to go -tx: *in vitro fertilization*

other benefits of VX-770 (2)

1. ASL volume/height reduced ~50% in CF -if you can open the channel, that will help you to have more fluid on top of your cells. this study put a fixed volume on top of the cells and let them equilibrate. if you have G551D you equilibrate at a very low volume. *if you add VX-770 ASL volume goes up to approximate what you see with WT* 2. if you get the fluid back to where you should be and your mucous is back to normal you should be able to have normal CBF. they stimulate the cells with VIP which is something that stimulates cAMP and nothing happens. they on top of that they add VX77. *CBF is restored, similar to what's seen with WT CFTR*

infection with pseudomonas and progression of CF lung disease

1. people are born *uninfected* 2. in *1st months and years* of life, there will be period of *transient infections*. this is a period where we can actually modify the disease. if we now see pseudomonas as an early culture we can tx that and often get rid of it with about 90% efficacy. 3. ultimately, *pseudomonas will switch over and become chronic*. it will be in the lungs and we can't get rid of it. with that there are some associated changes in how they look, grow, which promote them being chronic and *resistance to clearance by different antibiotics*. 4. *inc inflammation --> more lung damage* we start from uninfected and overtime as we start to get chronic infections we start to get lung damage

what # of CF patients receive lung transplants? what are 3 reasons why lung transplant outcomes are not as good as other organ transplants why do these lung transplants tend to better than other other lung transplants?

1/3 of all lung transplants in a given year are for CF patients lung transplants do not tend to do quite as well as kidneys, heart 1. high exposure to CO 2. contact with env 3. *very immune organ --> tend to be more prone to chronic rejection* CF patients tend to do pretty well. they attach at the main bronchus. *these patients tend to do as well or better, prob bc they're younger*. while they may have other comorbidities they *don't have 60-70 years of comorbidities*. they still have to address nutrition, enzymes, vitamin supplements

what are the 2 current approved drugs for use in CF and what do they target?

2 drugs currently approved large number of studies in progress rapidly changing field

lung inflammation in CF what are the 3 phases?

3 phases: *early, dramatic, relentless* mucous, infection, inflammation H&E pic = airway full of a plug that's full of neutrophils advanced bronchiectasis in a CT scan and a lung pathology specimen. outcome of the chronic inflammation we see in CF multiple contributors

which CF therapy has the potential to change the disease?

evidence based therapies for CF, he said all of these *CFTR modulators have the potential to change the whole disease.* in theory if you restore CFTR, you won't have the other effects. particularly if you can start soon enough

Kalydo vs. Orkambi

Kalydo - when used as a monotherpay in patients with G511D makes a huge benefit in lung function Orkambi = combination of lumacaftor + ivacaftor who have 2 copies of F508. we only get about 1/3 of the effect. we want to add a 2nd corrector on top of this so you have 2 correctors + 1 potentiator and hopefully that will take you up around the range of this benefit

if CF patients are chronically infected with MRSA how does this change their death risk?

MRSA is a common pathogen found in about 20-30% of patients this study looked at 20,000 patients for a number of years. they looked at the mortality rate of patients who were chronically negative vs. chronically positive for MRSA. they found that *if you're chronically infected with MRSA you have a 34% inc in death*

where in the airway can CF symptoms begin?

most of the disease manifestations that are life limiting are in the airways. the *airways begin in the nose and that's where symptoms in CF can begin* - sinus disease is not unusual

RhDNase/dornase alpha how is it taken? MOA? what 2 things does it improve?

RhDNase/dornase alpha - *inhaled drug* *chops up DNA* - it's very sticky and CF mucous is full of it. there are lots of neutrophils that go into your airway to clear up infection, they die, they leave their DNA behind and it contributes to thick, sticky mucous study looked at rhDNAse inhaled 1-2x per day compared with placebo. proportion of patients who were free of having an exacerbation - *proportion of free of exacerbations goes down quicker than if you're on a DNAase*. ends up being about *28-30% reduction* depending where you look and if you're looking 1 vs 2x per day dosing. *~5% improvement in lung function* in the treatment patients.

AZM in CF patients without PsA what did it improve? (3) what did it not improve? when is AZM recommended to start? is there a difference if the patient has PsA or not?

follow up study looked at young kids, had to have lung function >50%. age around 10. they did not have PsA. looked to see if this drug is beneficial if you don't have advanced disease. *showed 50% reduction in exacerbation frequency. also improved weight, less symptoms* NO DIFFERENCE IN LUNG FUNCTION** *recommended to start at age 5* *clearly has beneficial effects, independent of whether you grow pseudomonas*

what are 6 methods to control infection in CF?

a lot of things are important in CF infection control there's a risk that is ubiquitous most get pathogens from env. can demonstrate person to person transfer, particularly in families if they're siblings they often share the same bacteria. patients that are not related and not interacting, it's extremely unusual to find the same strain. it will be PsA for example but a different strain that came from the env hand washing, care of equipment, masks, limited exposure, cohort patients, no sharing (equipment)

CFTR modulator targets (5) - which one could be beneficial to all CFTR mutations? how can they be given?

drugs that suppress stop mutations work in the early steps of biosynthesis, if you have a premature stop mutation corrector will work on folding in the ER potentiator will work on CFTR at the cell membrane but won't open correctly *drug that's am amplifier might be beneficial to everyone* *these drugs can be mixed and matched - double and triple therapies to tx CF causing mutations*

lung infections in CF which 3 pathogens are common? which is becoming an emerging problem?

age groups and % of patients with resp infections green = *staph*, predominant pathogen in kids red = *MRSA*, subgroup about 1/4-1/3 will have MRSA blue = *pseudomonas*, one of the pathognomonic bacteria in CF. other pathogens are less common non Tb mycobacteria = emerging problem that's being found in more CF patients. really difficult to tx, 18 mo of therapy

repetitive slide not memorizing

airway clearance implies using devices - hand, vest, autogenic. these things are done at a minimum of 2x per day. variety of other ways to help get mucous out can also change the properties of the mucous - hydration, things that break mucous up, infection, inflammation

4 major components of pulmonary pathology in CF

all of these lead to progressive lung damage 1. *ion transport* 2. *mucous plugging* 3. *inflammation* 4. *infection*

experiment showing difference between normal airway and CF cells when volume is added

black = airway epithelial cells red = fluid that's sitting on top study took normal airway cells and CF airway cells and they added a common amount of volume to both of them. after 6 hours what you see is that the normal side is more compared to the CF condition. at 48 hours, this difference between CF and non CF is maintained. that represents over absorption of fluid that's going on at the airway surface right pic - in CF, the airway surface liquid height drops below the critical value to allow your cilia to do good work EM pic - cilia are crushed and not moving at all. fluid dehydration interrupts how well the mucous is cleared

CFTR modulator targets (5)

cell looking at a variety of different classes of nonfunctional CFTR proteins may have a premature termination codon so you make very little protein, there's another one where the protein doesn't fold correctly, there's another one where the channel gets to the cell membrane but won't open correctly, can have a situation where the channel will open but it's too small, can have channel not staying at the cell membrane long enough, can have a normal channel but you don't make very much of it due to a splicing problem potentiator - helps open CFTR and improve fating corrector improves tracking and folding suppressor suppresses stop codon and helps a protein that has a premature stop codon in the open or reading frame to read past that and then allow it to make a protein stabilizer helps hold CFTR at cell membrane for longer period of time amplifier inc amount of mRNA and hopefully inc everything downstream

dx of CF 3 major criteria for dx

combination of factors primary one is that you have an abnormal sweat test. sweat/Cl conc > 60. the average for adults it's 15-20 also need to have organ manifestations - GI tract, nutrition, panc insufficiency, sino-pulmonary infections, liver, male report tract (sterile due to blockage of vas def), sweat gland positive genetics --> close to 2000 mutations that have been identified in CFTR gene which causes CF. can never be 100% sure with genetics

combining correcting and potentiating targets of F508del

combine the folding drug with a 2nd drug - the potentiator they have begun to look at Vx809 in combination with 770 dose response curve with VX809 alone gets to about 15% of normal. if you add 770, you get twice the effect and in the range of 30% of normal. that might be enough to have a clinical benefit. this has lead to 2 huge studies

summary of lung infections lung infections in CF patients direct relate to what? mangement depends on what?

common *directly relates to loss of lung function depending on pathogen - pseudomonas, sepacia* limited number of pathogens (not things like strep pneumo) *management depends on type of infection*

what's wrong with F508del FDTR?

deltaF is in NBD-1 when this is missing, it causes instability of the green domain (it's wiggly/loose) and it doesn't interact correctly with other domains (MSD-2) those 2 things cause it to be recognized as abnormal and sent to the proteosome where it's broken down and very little gets to the membrane

hypertonic saline how does it compare to normal saline? what 2 things did it improve? which had a more substantial improvement?

hypertonic saline - gets used in different ways but is most clearly demonstrated to be beneficial in CF patients *inhaled saline that's about 2x the salt content of salt water* - *7% hypertonic saline* compared with control on regular saline. top pic = *3-3.5% improvement in absolute improvement in lung function (FEV1 in mLs)* bottom pic = *most benefit is shown in proportion free of exacerbation*s. on placebo you rapidly cross the threshold of having exacerbations (8-10 weeks). in the 7% HS patients it was extended out to about *36 weeks* *biggest effect was improvement in disease stability but also had measurable in improvement in lung function* only 60% of patients will take this regularly also can be pretty irritating - helps draw water in the mucous. it's more hydrated, looser, and easier to clear

what chromosome is the CF gene located and what does it produce?

in CF, there's a problem with the gene when the gene is transcribed into mRNA then goes into the ER where it's translated into a protein. has to go through folding steps which is a normal process for proteins. finally gets transported up to the plasma membrane of the different tissues where it's expressed. it's a channel/pore

not important

it's a very active field - lots of drugs in development challenge is how do we accomplish this

efficacy results of Ivacaftor (VX-770) 0 5

key outcome measures that were profoundly impacted with tx of drug 1. *10% improvement in lung function* that's retained throughout study compared to placebo 2. *risk of exacerbation is cut in half* 3. *quality of life measure shows benefit* that crosses the threshold of measurable benefit 4. *weight gain* - patients gained about 7 lbs compared with placebo 5. *sweat Cl dropped from about 100 to around 50*. very profound effect on CFTR, below diagnostic criteria for CF

how does CF cause high [salt] in sweat?

leads to high levels of high salt in sweat glands at the bottom is the glandular part - that's where Na+, Cl-, and H2O are transported into the lumen. it's isotonic at this point. normally, as the sweat is pumped up to the skin surface, on the left side most of the Na and Cl are reabsorbed back by the person. you end up with a low salt conc bc most of it gets reabsorbed. on the right side you have a CF patient and they fail to reabsorb the Cl and it's also unable to be transported bc you have to maintain electrical neutrality and you end up with a high conc of salt on the skin surface

CF is most common in which patient population? in which population is it growing? in which population is it unusual?

longevity up to 41+ years. huge advance but average life is half that of average american 1 in 3000 births, varies across ethnicities *most common in Caucasians and Northern European descent. 1 in 2500 births* growing population in hispanics - from up 2% african american populations unusual in asian populations (not known if it's failure to detect or screen for it) seen more frequently in arabic population. genetics are different but disease process is the same

CF sputum is enriched with what? what cell type is found in CF sputum that shouldn't be there? what markers are associated with this cell type? (3) what inflammatory markers are released from the epithelium? what inflammatory markers are released from the macs? (3) sputum biomarkers can be used to track what?

major things - *lots of neutrophils*. normally there are not many neutrophils in the airway. if you do a BAL, 90% of what you get is macs. 4.5% is lymphocytes, 0.5% is anything else. neutrophils do not belong. with neutrophils comes lots of things - *LTB4, IL-8, elastase*. these are all things that can promote inflammation, damage, and call in more neutrophils epithelial cytokines released - IL-6 (also looks like IL-8 from the picture) macs also release cytokines to help orchestrate the inflammation it's persistent inflammation

growth parameters by age in CF

median BMI percentiles between 1990-2008 there has been some improvements in this but we still have a long way to go *once patients get into adolescents they tend to drop below the 50th % in BMI*

age specific prevalence of pseudomonas from birth to age 16 what % of CF patients will have pseudomonas at 1st year or life, 2nd year of life, and 3rd year of life? what does this progression indicate? early in childhood, most of the pseudomonas is what type? what about in later teen years?

prior to intervening to try and get rid of pseudomonas infection, over the 1st few years of life the number of patients who have never had an infection with pseudomonas rapidly declines 1st pic = age specific prevalence to have no pseudomonas (PA). -in 1st year of life ~70% have not had pseudomonas -by 2nd year of life we're down to ~35% -3rd year of life you're down to ~20% -*rapid decline* bc pseudomonas is a *day to day exposure in very low amounts* but *CF patients have a difficult time clearing it* 2nd pic = prevalence of patients who only have nonmucoid PA (transient). *early in childhood, most of the pseudomonas we see is nonmucoid / not chronic* 3rd pic = prevalence of mucoid and non mucoid. *as CF patients get older, they get a regular inc in chronic infection*. before we were intervening the vast majority of adolescent patients were chronically infected with pseudomonas (*mucoid type*)

does the MIC of the pseudomonas matter when using TOBI? how does TOBI compare to placebo?

profound effects on the amount of bacteria this is looking at the drop in colony forming units in sputum of CF patients when on tobramycin. about 2 logs. the impact on bacterial density goes down rapidly. the dramatic killing goes down but it does have continued pretty effective suppressive benefit *declining effects placebo over time vs placebo* it didn't really matter if you were "resistant" to the PsA -*patients who have higher MIC breakpoints responded just as well as those with lower MIC breakpoints* -prob bc the mucous level of AGs is in the 1000 micrograms per gram of sputum. its levels are so far above what you would use IV that these numbers become irrelevant

what is a pulmonary exacerbation of CF? what's the impact on an exacerbation on a patient's lung function? why are these exacerbations important?

pulmonary exacerbation - *period where patients have more symptoms* (cough, weight loss, feeling sick, low grade fever, loss of lung function) what's the impact on an exacerbation on a patient's lung function? -study looked at 1500 patients' lung function before, during, and after a pulmonary exacerbation -right after treatment there's a nice recovery but *6 mo afterwards, you lose about 3-4% of lung function that you never recover* -25% of patients fail to recover back to 90% of starting *want to maintain stability and reduce risk of exacerbations in CF*

when should you start a patient on a CFTR modulating agent?

red = normal trajectory to predict lung function in a CF patient who has G551D patient using standard therapies *if you start a drug early you change the trajectory*

tobramycin system for inhalation (TOBI) what are the 3 beneficial affects of using TOBI for CF patients?

relatively large group of 520 subjects who were PsA+. randomized to alternate month therapy with nebulized tobramycin 2x daily vs. placebo gray bars = period on active drug on tobramycin there's about an *11% improvement in FEV1*. tends to drift down when you're off drug, up when you're on drug. this effect tends to wane overtime but clearly showed that using cycled antibiotics to tx PsA in chronically infected patients is beneficial 1. *11% improvement in lung function* 2. *26% Decrease in hospitalization* 3. *37% Decrease in IV antibiotics*

what are the 2 cells in the resp epithelium that release mucous? what are the genetic variants associated with them

resp epithelium - pseudostratified columnar epithelium mucous is made in goblet cells, also made in submucosal glands down below surface of epithelium *submucosal glands* help to pump mucous out to the surface and then it's modified. hydration is managed by the airway epithelium. *in addition to that goblet cells contribute mucous* goal is to have an extended ciliary blanket. the cells lining the airway epithelium have their cilia fully extended the mucins or mucous proteins that are released are 2 types - MUC5AC (goblet cells) and MUC5B (submucosal glands)

Na+ and Cl- transport in normal and CF epithelium

right side = airway epithelial, normal Cl absorption, normal Na+ absorption, maintaining a nice volume for the cilia to do their job. the mucous that overlies it is not terribly thick. that is optimized to help with muco-ciliary clearance left side = CF. the loss of CFTR disrupts how Cl is absorbed. it's believed to be transported between cells as opposed to through them. the other important thing is that there's way too much Na+ absorption. this activity is felt to drive dehydration of the mucous that's lying above. overtime this is thought to get in the way of normal mucociliary clearance

with loss of CFTR, what 2 electrocytes dec? what electrolyte inc and what does this contribute to? inc production of mucous can lead to what 3 things?

when we lose CFTR, we lose Cl transport. HCO3- is also transported by CFTR. prob important bc it impacts how sticky the mucous is and how well the innate immune system is able to clear infection there's also an inc in Na+ transport. regulatory relationship between Cl transport and Na+ transport through ENaC. *if you lose CFTR, that releases ENaC to do too much and it tends to overwork, over absorb Na+ and that contributes to dehydration* top pic: surface of airway of CF patient, can see thick mucous coming out of a submucosal gland bottom pic: plug of mucous in a medium bronchiole the amount of mucous you make is too much, it tends to have a viscosity. this sets up a perfect stage for infection, inflammation, and over time leads to airway damage