Scientists may have found a clue to why people living with HIV have double the likelihood of developing heart disease. The findings, made by researchers at the University of Pittsburgh Center for Vaccine Research and National Institutes of Health, also show that an experimental drug may hold promise as a potential treatment.
The increased heart disease risk is driven by a subset of immune cells in people with HIV which continue to express a protein that triggers blood clotting and inflammation even after the HIV virus is under control by medication, the scientists explain in Science Translational Medicine.
Furthermore, the researchers found that Ixolaris, an experimental drug isolated from tick saliva and previously tested to treat blood clots in animals, successfully reduced the inflammation in monkeys infected with SIV, the primate form of HIV.
“People are living long, fruitful lives with HIV thanks to tremendous strides in antiviral treatment regimens, however those lives are being cut short due to perplexingly high rates of heart disease,” said co-senior author Ivona Pandrea, M.D., Ph.D., professor of pathology in Pitt’s Center for Vaccine Research. “By uncovering one of the cellular mechanisms driving the heart disease, we can look for medications – such as Ixolaris – that specifically target and disrupt that mechanism.”
Co-senior author Irini Sereti, M.D., of the NIH’s National Institute of Allergy and Infectious Diseases (NIAID), tested blood samples from people without HIV, people with HIV whose infections were well-controlled by antiretroviral therapy and people with HIV who weren’t on the medications. The researchers found an elevated number of immune cells called monocytes that expressed high levels of the ’tissue factor’ protein, which is associated with blood clotting and other inflammatory proteins, in the blood from people with HIV, regardless of how well their infection was controlled.