We've all been told to avoid ticks -- those blood-sucking insects that can be smaller than the period at the end of this sentence but cause a lot of trouble, nonetheless. Deer ticks, in particular, are known to carry Lyme disease, which causes headaches, fever, fatigue and joint pain. But scientists believe that the very thing that makes these bugs good at spreading disease -- their saliva -- might also be able to reduce heart disease in people living with HIV.
The risk of heart attack is 1.5 to two times greater in people living with HIV than in the general population, even if they are on antiretroviral therapy and have no detectable virus in their blood. They share common cardiovascular disease (CVD) risk factors with everyone else in our society, including obesity, hypertension and smoking. In addition, some HIV medications are known to increase levels of cholesterol and triglycerides. There is also some evidence that the presence of HIV in tissue throughout the body causes chronic inflammation that can lead to plaque build-up in the heart. People living with HIV have been found to have plaque on their heart about 10 to 15 years earlier than those who do not have the virus. This can be a cause of both heart attacks and strokes.
The authors of a new study believe that this underlying inflammation is caused by an overabundance of a type of immune cell that releases a certain protein. The protein then triggers both inflammation and blood clots. Tick saliva blocks blood clotting (also called coagulation) in to order to allow blood to flow freely into the biting insect. Scientists have already isolated the compound in tick saliva that prevents blood from clotting and created a synthetic version called Ixolaris.
For this study, which was published last month in Science Translational Medicine and reported in The Washington Post, researchers first tested Ixolaris on blood samples from people living with HIV and found that it blocked the inflammation-causing protein. The researchers then tested Ixolaris on two different groups of lab monkeys that had SIV (simian immunodeficiency virus) and found that it blocked inflammatory proteins in a particular species of monkey that was more likely to develop heart disease when living with SIV.
The authors believe that this research represents a promising start to both understanding the role that inflammation and coagulation plays in heart disease risk and, more importantly, to treating it.
But some experts think we should be looking for simpler, more immediate solutions to the problem of heart disease in people living with HIV. David A. Wohl, M.D., an HIV/AIDS expert at the University of North Carolina Medical School, told TheBody.com in an email that "the tick thing was novel" but not necessarily important. In his opinion, the role that inflammation and clotting play in the increased risk of heart disease is less important than more traditional risk factors for heart attack. He explained: "Pinning the lion's share of excess CVD risk on these poorly understood sequelae of HIV infection, I worry, distracts us from better applying the major interventions we know work to reduce cardiovascular disease risk. We don't need tick spit, we need more and better control of hypertension, obesity, tobaccoism and bad lipids."
Unfortunately, rolling around in the grass and hoping for a tick bite is not going solve any of these issues (and can lead to Lyme disease and other tickborne illnesses). So, instead, it's back to the basics of eating well, exercising and quitting smoking. It is also important to see your health care provider regularly to check your blood pressure, cholesterol and triglycerides, as well as to change or add medications if necessary.