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The return of Aspirin for HIV infection

<p>Sean R. Hosein</p>


October 1, 2012

Since the early 1990s, researchers have been aware that HIV infection was associated with excessive inflammation. Some researchers suspected that HIV-related inflammation weakened the immune system in particular and the body in general. One drug that can partially reduce inflammation is Aspirin. Laboratory experiments with anti-inflammatory compounds (including Aspirin) and cells and HIV have found that these drugs can partially reduce inflammation and, in some cases, the production of HIV from infected cells.

A pilot study of Aspirin was done in the early 1990s in New York City. However, this study did not uncover any substantial benefit in HIV-positive people. Note that at the time, potent combination therapy for HIV infection (commonly called ART or HAART) was not available.

Since then, Aspirin has been tested and continues to be tested in clinical trials of HIV-negative people. In these studies, daily Aspirin has generally been found to modestly reduce the risk of developing a number of cancers.

Aspirin helps to reduce the formation of blood clots, which can clog blood vessels and lead to a heart attack. However, Aspirin can also lead to an increased risk of bleeding in the stomach, intestines and brain, so Aspirin therapy should always be done under the supervision of a physician.

HIV and cardiovascular disease

Many studies have found that HIV-positive people have an increased risk for cardiovascular disease. Likely this is brought about by inflammation triggered by chronic HIV infection. In monkeys susceptible to infection with the closely related simian immunodeficiency virus (SIV), researchers have found that these monkeys have an increased risk for cardiovascular disease.

Platelets

Platelets are small cells found in blood that help to initiate the formation of blood clots. When platelets become activated, they release proteins that quickly cause clots to form. When cuts and injuries occur, such clots help to prevent the loss of blood and death. However, in HIV infection, platelets appear to be prone to activation and excessive incitement of clot formation.

Researchers in New York City recently conducted a relatively short and small study of low-dose Aspirin (81 mg) for one week to assess its impact on several measures of inflammation, clotting and immune activation. They found that after one week Aspirin had beneficial results on laboratory assessments of these issues. A longer and larger study is now needed to confirm and extend these results.

Study details

Researchers recruited 25 HIV-positive participants on stable ART and 44 healthy controls. The average profile of the HIV-positive participants was as follows:

  • 76% men, 24% women
  • age – 50 years
  • CD4+ count – 630 cells
  • current smokers – 56%
  • HBV co-infection – 8%
  • HCV co-infection – 24%
  • family history of heart attack – 16%

Blood samples were collected before and after the study.

Results

Prior to using Aspirin, lab tests found that HIV-positive participants had platelets that were hyper-reactive. Such a state greatly enhances their ability to initiate the clotting process.

One week’s exposure to low-dose Aspirin significantly reduced platelet hyper-reactivity. Moreover, Aspirin appeared to reduce the activation of CD4+ and CD8+ T-cells. Also, in simulated experiments, after one week, white blood cells taken from Aspirin users were more responsive in attacking germs.

There was a general statistical trend for reduced levels of proteins in the blood associated with inflammation such as the following:

  • C-reactive protein
  • interleukin-6
  • D-dimer

No side effects were reported, but then this study used low-dose Aspirin and lasted for only one week. However, the present study provides a needed foundation for a longer and larger study to confirm these results and to assess the impact of this or other doses of Aspirin on the risk for heart attack. Such a study should also recruit more HIV-positive women.

—Sean R. Hosein

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