Tick saliva may hold potential treatment for reducing HIV-linked heart disease risk

August 30, 2017, University of Pittsburgh Schools of the Health Sciences
HIV infecting a human cell. Credit: NIH

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 risk is driven by a subset of 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 today's issue of Science Translational Medicine.

Furthermore, the researchers found that Ixolaris, an 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."

Irini Sereti, M.D., of the National Institute of Allergy and Infectious Diseases at NIH, discusses her latest findings on the interplay between inflammation and blood clotting in HIV infection. Credit: National Institute of Allergy and Infectious Diseases (NIAID)

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 and other inflammatory proteins, in the blood from people with HIV, regardless of how well their infection was controlled.

These findings were confirmed by Pandrea and her team in monkeys that progress to AIDS after infection with SIV. The same cells isolated from a different species of monkey that usually does not develop heart disease when infected with SIV do not produce tissue factor, thus reinforcing the role of this damaging protein in triggering cardiovascular disease in the HIV/SIV settings.

The scientists then exposed the human blood samples to Ixolaris and observed that the drug blocked the activity of tissue factor. When tested in a small group of monkeys during early SIV infection, the treatment significantly lowered the levels of linked to cardiovascular disease.

NIH holds the patent for Ixolaris, which is a small molecule found in the saliva of the tick Ixodes scapularis—commonly known as the deer or blacklegged tick—and was uncovered by study co-author Ivo M. B. Francischetti, M.D., Ph.D., of NIAID. More studies are needed to test the drug's safety and interaction with other drugs that are used for HIV patients. Ixolaris has not been tested in humans and the results could differ, the researchers also cautioned.

"This treatment has the potential to improve the clinical management of HIV-infected patients and help them to live longer, healthier lives with HIV," said Pandrea. "That, and other therapies that may arise from targeting the inflammation pathway we discovered, are exciting avenues for future research."

Explore further: Breakthrough in HIV/AIDS research gives hope for improved drug therapy

More information: M.E. Schechter at Leidos Biomedical Research Inc. in Frederick, MD el al., "Inflammatory monocytes expressing tissue factor drive SIV and HIV coagulopathy," Science Translational Medicine (2017). stm.sciencemag.org/lookup/doi/ … scitranslmed.aam5441

Related Stories

Breakthrough in HIV/AIDS research gives hope for improved drug therapy

May 16, 2014
The first direct proof of a long-suspected cause of multiple HIV-related health complications was recently obtained by a team led by the University of Pittsburgh Center for Vaccine Research (CVR). The finding supports complementary ...

Study explores prevention of heart disease in HIV-infected people

October 28, 2014
The National Institutes of Health has launched a clinical trial to assess the effects of aspirin and cholesterol-lowering drugs, or statins, on preventing cardiovascular disease in people with long-term HIV infections. This ...

High-fat diet leads to same intestinal inflammation as a virus

June 22, 2017
A new study by scientists at UCLA found that when mice eat a high-fat diet, the cells in their small intestines respond the same way they do to a viral infection, turning up production of certain immune molecules and causing ...

Research helps explain how antibody treatment led to lasting HIV-like virus remission

February 15, 2017
Scientists at the National Institutes of Health have found that the presence of the protein alpha-4 beta-7 integrin on the surface of HIV and its monkey equivalent—simian immunodeficiency virus, or SIV—may help explain ...

Modified experimental vaccine protects monkeys from deadly malaria

May 22, 2017
Researchers from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, modified an experimental malaria vaccine and showed that it completely protected four of eight ...

Recommended for you

Obesity and health problems: New research on a safeguard mechanism

March 16, 2018
Obesity and its negative impacts on health - including metabolic syndrome, type-2 diabetes mellitus and cardiovascular complications - are a global pandemic (Taubes, 2009). The worldwide incidence of obesity has more than ...

Immune system 'double agent' could be new ally in cancer fight

March 16, 2018
St. Jude Children's Research Hospital scientists have discovered that an enzyme called TAK1 functions like a "double agent" in the innate immune response, serving as an unexpected regulator of inflammation and cell death. ...

Artificial sweetener Splenda could intensify symptoms in those with Crohn's disease

March 15, 2018
In a study that has implications for humans with inflammatory diseases, researchers from Case Western Reserve University School of Medicine and colleagues have found that, given over a six-week period, the artificial sweetener ...

Researchers identify common biological features of different types of asthma

March 14, 2018
A team of researchers from the NIHR Leicester Biomedical Research Centre - a partnership between Leicester's Hospitals, the University of Leicester and Loughborough University - has identified biological variations in lung ...

Scientists discover treatment target for sepsis

March 14, 2018
In a study published in Nature Communications, Northwestern Medicine scientists demonstrated the key role a molecule called oxPAPC plays in regulating the inflammatory response—findings which could inform the development ...

Researcher creates 'Instagram' of immune system, blending science, technology

March 10, 2018
Being on the cutting edge of science and technology excites Hollings Cancer Center (HCC) researcher Carsten Krieg, Ph.D. Each day, he walks into his lab that houses a mass cytometry machine aptly labeled Helios. Krieg explains ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.