30 Jan AIGHD, NIH, and Cedars-Sinai Collaboration Sheds Light on Gut Microbiota of People Living with HIV

AIGHD virtually sat down with Prof. Peter Reiss, Dr. Irini Sereti, and Ass.Prof. Ivan Vujkovic-Cvijin to discuss the recent paper they co-authored which looks at the relationship between People Living with HIV (PLHIV) and their gut microbiome.

You can find the open access paper here.

It’s an early morning call for Dr. Sereti and Prof. Vujkovic-Cvijin who were both in the continental United States but a late one for Prof. Reiss who is located in Amsterdam. “The paper is important for us because it shows the value of collaboration between AIGHD and other institutions and countries across the globe,” says Prof. Reiss. As a global health organization, collaboration and cooperation are critical for AIGHD as we perform our research and implement our projects. In our world, knowledge becomes most valuable when shared.

Unveiling the gut microbiota of PLHIV

“Generally, we say that a good gut microbiome is a diverse one, in contrast to a vaginal microbiome that typically wants to be highly specific. When the gut microbiome experiences a marked reduction in diversity, we call that ‘dysbiosis’,” says Dr. Irini Sereti, an infectious diseases physician at the National Institute of Allergy and Infectious Diseases and a PhD Candidate at the Amsterdam University Medical Centre.

In a previous publication co-authored by Dr. Sereti, they described the link between intestinal dysbiosis and markers of chronic systemic inflammation throughout the body in People Living with HIV (PLHIV). Meanwhile, in another cross-sectional study, chronic inflammation was also associated with developing clinical events in PLHIVs such as cardiac disease or cancer.

Inspired by these connections, Dr. Sereti wondered if the reduction in the microbiome diversity of PLHIVs who have experienced clinical events preceded these events or if they were a result of it. To conduct her study, Irini tapped into data and samples from the AGEhIV cohort study, which is managed by AIGHD and assesses aging and ageing-related diseases for PLHIV and for those without HIV.

Using the data and samples collected from the study, Dr. Sereti and the team looked into both the variety of bacteria available in the stool as well as the metabolites*, specifically short-chain fatty acids or SCFAs, in the bloodstream and stool. The production of these SCFAs are highly dependent on the enzymes produced by the microbiota and can have secondary effects in the immune system including decrease of inflammation.

Dr. Sereti confidently stated the findings, “For the first time, we can say that these reductions in microbiome diversity in PLHIV precede these (clinical) events and may even put them in the chain of pathogenesis,” adding that, “studying metabolites in plasma seem to better represent what is happening in the gut microbiome than the metabolites measured in stool.”

Dr. Vujkovic-Cvijin, a microbiome specialist and lead author, stated, “Butyrate and propionate are important anti-inflammatory SCFAs produced by the gut microbiome when fermenting dietary fibers and undigested carbohydrates.” Propionate was lower in the blood of PLHIV compared to the HIV-negative group. However, while butyrate did not necessarily see a depletion, enzymes involved in propionate and butyrate production were reduced.

When asked about possible implications in diagnostics or research, Dr. Sereti replied that she hopes that this new knowledge will help future researchers take a look at the relationship between the gut microbiome, SCFA production, and gut inflammation in PLHIVs.

Sharing Knowledge for Progress

The collective contribution of the AGEhIV cohort study, from the patients to the researchers, has helped us reshape our understanding of the gut microbiota of PLHIV. This newfound knowledge will be critical in shaping future interventions to help those who are living with HIV lead even better lives.

In conclusion, the virtual discussion with Prof. Reiss, Dr. Sereti, and Ass.Prof. Vujkovic-Cvijin not only highlighted groundbreaking research but also emphasized the power of global collaboration in advancing our understanding of health issues that transcend borders. As we navigate the intricate landscape of global health, it becomes increasingly evident that collective knowledge-sharing is the cornerstone for fostering meaningful progress. The journey from scientific discovery to practical applications is paved with collaboration, and the insights gained from this study contribute significantly to this collective endeavor.

Irini Sereti is an infectious diseases physician working at the National Institute of Allergy and Infectious Diseases. She is also enrolled at the PhD Programme at the Amsterdam UMC.

Ivan Vujkovic-Cvijin is an Assistant Professor at Cedars Sinai Medical Center as part of the Department of Biomedical Sciences. He studies the microbiome and how it interacts with the immune system.

Peter Reiss is an emeritus Professor of Medicine at the Amsterdam University Medical Center’s Department of Global Health. He has been working on HIV care and research since 1981 at the onset of the HIV/AIDS pandemic.

• Metabolites are small molecules that are intermediates or end products of metabolic reactions in living organisms.