The Dangers of Forgetting the Keys: HIV and aging on the brain

-Maria Lawrynowicz
Supervised by: Gilbert Mallais

Remember the CATIE article on HIV and aging? It said that more effective anti-retroviral therapy since the 1990s has increased the incidence of dementia in HIV patients and advised HIV+ individuals to seek medical advice when they have memory or focus issues. My question is who DOESN’T have memory and focus issues? How do you draw the line between what is normal and not? This article seems to offer some insight into what we do and do not know (mostly the later), as well as, what we should try to find out…

HIV Infection and Aging Independently Affect Brain Function as Measured by Functional Magnetic Resonance Imaging

Beau M. Ances,
Florin Vaida,
Melinda J. Yeh,
Christine L. Liang,
Richard B. Buxton,
Scott Letendre,
J. Allen McCutchan,
Ronald J. Ellis

available at: http://jid.oxfordjournals.org/content/201/3/336.full

Study presented at Conference on Retroviruses and Opportunistic Infections, Montreal; 8-11 February 2009

Compliant HIV+ patients could be considered a doctor’s dream… they are capable of following complex medication schedules, visit their doctors on a regular basis and lead a relatively healthy lifestyle, while staying mindful of their diet, exercise and so on. Such individuals are no strangers to minor body ailments that may come with a seropositive status and are accustomed to treating these as they come, however, it is much more difficult to perceive the highly camouflaged symptoms of cognitive changes from neuronal degradation with aging and/or HIV. Even the most vigilant people can fail to notice vague things, like forgetfulness or decreased concentration, often passing these off as “one of those days”.

Top 3 points from this article:

1. A group of HIV+/- subjects were examined with a fMRI (functional magnetic resonance imaging is known as “functional” because it measures changes in blood flow while your brain is working) to measure their cerebral blood flow and dissolved O2. The study found that cerebral blood flow of HIV+ subjects was similar to HIV- subjects who were 21 years older, while blood oxygen dependent signals were like those of HIV- individuals 15 years older.

2. What is causing this extra strain on the brain? Scientists believe that the increased metabolic stress due to normal aging compounded with metabolic stress from persistent inflammation that comes with any infection (even in HIV when you have an undetectable viral load), or immune dysfunctions, like reduced t-cell growth/ maturation or increased cytokine release (chemicals released by your immune cells to fight off infections),

3. What is the good news? There is no synergistic effect of aging and HIV infections i.e. they both function independently! What does this mean? Independent risk factors are discrete things that predispose people to a particular condition, in this case, HIV associated neurocognitive disorder. This means that BOTH being HIV+ and aging does not make it any more or less probable that your brain will have a neurocognitive disorder. With this information, future studies should be directed at determining causality (why does blood flow change?) so that researchers can work to find a therapy that could mediate the effects seen in this study. This study opens the door to potentially important changes in HAART in the coming years….