If you’re living with pulmonary hypertension (PH), you may be wondering whether the condition is connected with any other chronic diseases. One condition that scientists believe has a link to PH is human immunodeficiency virus (HIV).
Read on to learn more about the connection between these conditions and why people with HIV have a higher risk of developing PH.
Pulmonary hypertension — high blood pressure in the lungs due to any cause — affects an estimated 1 percent of people worldwide.
The risk of developing PH increases in people infected with HIV. Researchers estimate that in developed countries, up to 0.5 percent of hospitalized people with HIV also have PH. Compared with the general population, people who have HIV are 6 to 12 times more likely to develop PH that is idiopathic (of unknown cause), according to the Pulmonary Hypertension Association.
Though it’s clear that HIV and PH are connected, scientists are still researching this link.
There are five types of pulmonary hypertension, based on different causes of the condition. The World Health Organization (WHO) has defined the types as:
Symptoms of pulmonary hypertension include:
Some people may have no symptoms.
HIV specifically infects and destroys important cells in the immune system called T cells (a type of white blood cell called T lymphocytes). As HIV progresses and T-cell count decreases, the immune system cannot fight back against other dangerous viruses and bacteria.
The condition that can result from HIV suppressing the immune system is called AIDS. People with HIV/AIDS have a weakened immune system, which can lead to other life-threatening infections if untreated. HIV-positive people are also at an increased risk of cardiovascular disease and pulmonary diseases, such as PH.
According to a study from the journal Circulation, the first report of a person with both PH and HIV occurred in 1987, when HIV was rapidly spreading throughout the U.S.
Scientists are still working to understand the role of HIV in pulmonary hypertension. Researchers have found that HIV does not infect the cells that make up the heart, lungs, and pulmonary arteries. Therefore, HIV-related damage to the lungs and pulmonary arteries is believed to be indirect.
HIV cannot infect the lungs and pulmonary arteries, but proteins made by the virus can travel through the body and cause changes that disrupt normal blood flow to the lungs. These proteins may be taken up by cells and lead to the activation of signals that change how the cells grow.
The viral proteins that may contribute to the development of PAH include glycoprotein 120 and the transactivator of transcription (Tat) and Nef proteins.
Glycoprotein 120 is one of the proteins that make up the outer layer of HIV and is responsible for getting the virus into human cells. Studies show exposure to this protein triggers cells to grow differently, which can lead to vascular remodeling and restriction of the pulmonary arteries.
The HIV Tat protein increases the expression of HIV genes. The Tat protein can be found in cells that make up the lung blood vessels and, like glycoprotein 120, contributes to the remodeling of blood vessels.
Nef is an HIV protein critical to the life cycle of the virus. Studies show that the HIV-1 Nef protein can cause abnormal growth in the lung arteries called plexiform lesions, which block blood flow and contribute to pulmonary hypertension.
A risk factor for contracting HIV is intravenous drug use — shared needles can spread the virus from an infected person to someone else. The Centers for Disease Control (CDC) reports that about 10 percent of all new HIV infections are due to drug use, and UNAIDS states that the risk of acquiring HIV is 35 times higher for people who inject drugs. Although several illegal drugs are considered possible causes of PH, studies suggest that the combination of HIV infection and drug use can increase injury and remodeling in the pulmonary arteries, leading to PH.
People with HIV are living longer due to medical advances. However, the increased longevity often comes with additional chronic diseases that can cause pulmonary hypertension. People with HIV have a high risk of developing chronic pulmonary diseases and respiratory symptoms, increasing the risk of PH due to lung disease (group 3). There is also an association between HIV infection and heart failure — specifically, left heart disease, the cause of group 2 PH.
More than 36 million people have died from AIDS-related illnesses since the start of the HIV pandemic, according to UNAIDS. Fortunately, advances in highly active antiretroviral therapy (HAART) targeting HIV have improved the survival rate and quality of life for people living with HIV. These medications disrupt the infection cycle of HIV, lowering a person’s viral load.
The role of HAART in HIV-PH is still not well understood. PH medications might change how HIV medications work or vice versa. Some studies suggest that certain antiviral medications, like ritonavir (Norvir), can further contribute to PH. Ritonavir can also change how a PH medication called sildenafil (Revatio) moves through the body. Some PH medications like bosentan (Tracleer) work well in combination with HAART.
If you are managing HIV-related pulmonary hypertension, talk with your doctor about which medications for each condition are compatible.
On myPHteam, the social network for people with pulmonary hypertension and their loved ones, more than 46,000 members come together to ask questions, give advice, and share their stories with others who understand life with pulmonary hypertension.
Are you managing HIV-associated pulmonary hypertension? Share your experience in the comments below, or start a conversation on your Activities page.