Changes in gut bacteria could worsen HIV disease

Changes in intestinal bacteria could explain why some successfully treated HIV patients continue to experience life-shortening chronic diseases earlier than the uninfected, according to a study published on Wednesday in Science Translational Medicine.

Researchers with the University of California at San Francisco investigated the gut microbiome of HIV patients and found a higher presence of bacteria associated with inflammation. Previous studies showed that inflammation induced by HIV may cause disease in both treated and untreated patients. Persistent inflammation may be the cause of the early onset of common chronic diseases.

"We want to understand what allows the virus to persist in patients who have HIV disease, even after treatment," Joseph McCune, a senior author of the study, said. "In this study, we see that bacteria in the gut may play a role."

McCune's team compared seven untreated HIV patients, 18 HIV patients in whom ongoing drug treatment reduced HIV in the blood to undetectable levels and nine uninfected individuals with other health risks.

"We found that HIV-infected people have a very different gut microbiome than people who are uninfected," Ivan Vujkovic-Cvijin, a graduate student working in McCune's lab, said. "In particular, infected people harbor more bacteria that can cause harmful inflammation, like Pseudomonas, Salmonella, E. coli, and Staphylococcus."

The researchers said that changes in the microbiome could result in increased inflammation in HIV-infected patients. To remedy the situation, a restoration ecology approach could restore proper microbial colonization patterns and reduce inflammation.

"Our dream is to be able to make the virus go away, allowing HIV-infected people to lead longer lives without the need for life-long therapy," McCune said. "Perhaps restoring the microbiome to normal will be one strategy to make that happen."