Study shows how probiotic improves integrity of the GI epithelial cell wall in HIV patients

A newly released study published in the Journal of Immunity, Inflammation and Disease and conducted by the Sapienza University of Rome, Italy, found a multi-strain, high concentration, probiotic formulation that helped reconstitute the physical and immunological integrity of the gastrointestinal lining in HIV-1-positive patients on antiretroviral therapy (ART).

The human gastrointestinal (GI) tract is home to trillions of organisms which form a complex bacterial community, commonly referred to as the "gut microbiome." A key function of the GI tract is to separate these bacteria from internal organs with a single layer of intestinal cells, called epithelial cells. The epithelial cells form a physical and immunological barrier to prevent entry of gut bacteria into the bloodstream. When this barrier breaks down, or becomes compromised, it can result in a dangerous circulation of bacteria throughout the body.

In patients with HIV, this "barrier function" of the GI tract is damaged by the virus starting very early after viral acquisition. Even when the disease is treated with antiretroviral therapy, the integrity of the GI tract often remains severely compromised. This lack of a proper barrier can result in a low-grade, long-term, systemic immune activation and inflammation which is commonly associated with a variety of HIV-related comorbidities, such as cardiovascular disease, kidney disease, diabetes, and bone fracture.

Probiotic bacteria have been shown to help support this barrier function through a variety of mechanisms, including the competitive exclusion of damaging bacteria and the release of bioactive compounds, such as butyrate, which help tighten the junctions between the epithelial cells. In this longitudinal pilot study, a high potency, eight strain probiotic formulation (commercialized as Visbiome^TM in the United States and Vivomixx^TM in Europe) was evaluated in long-term treated HIV-positive patients on ART to determine the product's safety and impact on gut barrier function. The investigators observed several clinical and biochemical indicators, which showed an improvement in the integrity of the gastrointestinal epithelial cell wall and an overall reduction in damaging systemic inflammation.

"We believe this is the first time a probiotic has been shown to clearly improve the integrity of the GI epithelial cell wall in HIV patients," said Dr. Giancarlo Ceccarelli M.D., Ph.D., a clinical researcher and HIV treatment specialist at the Sapienza University of Rome who actively conducted the study. "There appear to be multiple therapeutic mechanisms at work, but the improvement in Th17 immune cells in the GI tissue was of particular interest. In the HIV population, a depletion of Th17 in the gastrointestinal tract is common and is a significant driver of the loss of intestinal barrier function."

There were no adverse safety-related findings associated with Visbiome^TM. The investigators also cautioned against broadly translating this research to all probiotic products, noting that the clinical findings for probiotics should only be applied to the specific strains evaluated, particularly when dealing with an immunocompromised patient population.

Two large studies are currently underway in the United States and Canada to further evaluate the impact of Visbiome in HIV. A multi-center study, being conducted by the NIH funded AIDS Clinical Trials Group (ACTG), is seeking to determine if the product can reduce damaging systemic inflammation in HIV patients in comparison to placebo. Results of this study are expected in early 2018.