After the in class discussion of T and B cells and their relation to stroke size and inflammation, I began to wonder: “How do
HIV/AIDS patients fare when it comes to stroke? Since T cell mediated cytokine
release and stroke lesion size are proportional, then does that mean that in a
HIV/AIDS patient who has compromised T cell levels, his/her incident of stroke
would be decreased?” Unfortunately,
after some research, it appears that having HIV/AIDS actually increases the
risk of not only ischemic stroke, but also hemorrhagic stroke. The most
striking aspect? This increased risk of stroke in HIV/AIDS patients seems to be
most prevalent in young diseased populations that display none of the
traditional stroke risk factors: high cholesterol, tobacco use and smoking,
obesity, and diabetes.
So if they aren’t at risk for stroke in the traditional
sense, then what’s causing the increased incidence of stroke in young HIV/AIDS
patients? The tentative answer is vascular remodeling and cardioembolic
conditions. Studies show that HIV/AIDS patients display higher rates of
atherosclerosis, the hardening of arteries due to plaque build up. The
increased rate of atherosclerosis is casually correlated with the vascular
remodeling that HIV/AIDS individuals present with. Moreover, these atherosclerotic
conditions facilitate the development of cardiomyopathies such as marantic
endocarditis (growth on the heart valves), myxoid valvular degeneration
(weakening of connective tissue in heart valves), dilated cardiomyopathy (an
enlarged and weakened heart that cannot efficiently eject blood), and
myocardial infarction (heart attack). As a result, the risk of stroke in diseased
patients is significantly increased upon having these conditions.
As if being at higher risk for stroke wasn’t enough, it is
extremely difficult to treat HIV/AIDS individuals once they experience stroke,
since there is little information/limited treatment available. Currently, we
know little about the effects of traditional stroke therapy (anticoagulants,
blood pressure lowering drugs) on the antiretroviral already prescribed to
HIV/AIDS patients. Consequently, there is currently no specific treatment for
HIV/AIDS individuals who experience stroke.
Sources:
"Am I at Risk for a Stroke?" Stroke Risk Factors. National Stroke Association, 2014. Web. 05 Oct. 2014.
Dobbs, Michael R., and Joseph R. Berger. "Stroke in HIV Infection and AIDS." Expert Review of Cardiovascular Therapy 7.10 (2009): 1263-271. Web.
I found that article very interesting, as I was also thinking more about whether or not HIV/AIDS patients would have a decreased risk of stroke due to low T cell count. I looked a little more into it and found that many medications that treat HIV/AIDS, specifically protease inhibitors, are also associated with increases in visceral fat. An increase in visceral fat, which for all of us that have taken 303a should know, is associated with the development of the metabolic syndrome; which in turn is a risk factor for stroke. I think that this could just be another case of patients/doctors deciding what is the greater threat to quality of life, increased risk of stroke or developing AIDS. Regardless I think this is an area that could benefit from more research because as AIDS patients are starting to live longer we need to start focussing less on just extending their lives and more on improving what life the drugs give them.
ReplyDeleteYou asked, “How do HIV/AIDS patients fare when it comes to stroke? Since T cell mediated cytokine release and stroke lesion size are proportional, then does that mean that in a HIV/AIDS patient who has compromised T cell levels, his/her incident of stroke would be decreased?” This is a great correlation that I would have looked into myself. With further research I found a few articles that confirmed that in 1997 a new drug was released for HIV patients, 9 years later a study was done determining how the number of HIV stroke patients has changed in that course of time. The number of HIV patents that experienced a stroke did nearly double after this drug came out. I agree that when a person has HIV/AIDS the doctor and that individual have to choose between the lesser of two evils due to the fact that there is no cure yet but it is good to be aware of serious complications that drugs can inflict on a patient.
DeleteOvbiagele B et al. Increasing incidence of ischemic stroke in patients with HIV infection. Neurology, online edition, 2011.
Thank you for the insight into how HIV/AIDS drug therapy affects incidence of stroke! I'm just curious as to how the drug causes an increased risk of stroke? Does it contribute to the vascular remodeling or does it add to visceral fat by inhibiting proteases like the drug Joel described? It would also be interesting to see how drug therapy has progressed through the years since 1997, and whether or not the risk of stroke has decreased.
DeleteI'm glad we were thinking on the same page, Joel! Thank you for looking into drug based reasons behind this increased risk of stroke-- it definitely makes more sense now. If a drug increased your visceral fat, it would only make sense that a disease such as stroke, for which a precursor is metabolic syndrome, would be more likely to present itself. I also agree with your line of thinking concerning choices physicians have to make: an increased risk of stroke vs. the threat of full blown AIDS. Indeed, now that research has come so far in prolonging their lives, perhaps the next step would be to try and alleviate the side effects of AIDS therapy. Although, the best case scenario would be a complete cure. A boy can dream!
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ReplyDeleteI had not considered the increased risk of stroke in people suffering from HIV/AIDS. Thanks for bringing this up, John. It seems like people with HIV/AIDS have the short end of the stick in every aspect because of their compromised immune system--wouldn't it be nice if just once they had some sort of advantage against some complication? I find it noteworthy that HIV/AIDS is a blood-borne disease. And a blood clot is the cause of ischemic stroke. This may just be coincidence, but I wonder if other diseases where the entity making people sick is found in the blood--such as hepatitis or malaria--could also increase risk of stroke.
ReplyDeleteHey Marissa! I agree-- HIV/AIDS patients seem to have the worst of both worlds. As for the correlation between HIV/AIDS being a blood borne disease and the increased risk of clotting, I think it's a more of a coincidence, rather than a strong correlation. This is due to the fact that clotting occurs primarily due to the clumping red blood cells, whereas HIV/AIDS attacks T helper cell machinery, which is part of the plasma portion of blood.
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