Researchers from the University of Valencia have established a link between certain species of gut bacteria and how well the immune system recovers after initial infection.
More significantly, the team observed this behaviour as both a consequence and as an aid in recovery.
The findings add to the body of research that identifies the gut microbiome’s role in a variety of disorders, either contributing to the condition or affecting duration and recovery time.
The gut microbiome has so far been implicated in the onset of inflammatory bowel diseases, obesity, diabetes, autism, and asthma.
“Gut bacteria appears to play a role in successful immune recovery in HIV-infected individuals,” said researcher Manuel Ferrer from the Catalysis Institute.
“Antiretroviral (ART) treatments could therefore have a greater impact on HIV patients’ health if combined with therapies that target this subset of bacteria. “The design of new probiotic foods could be an option, for instance,” he added.
The idea is not a new one. Probiotics along with fermented foods have previously been suggested as a way to attain an optimal gut flora, and to “reseed” the gut in individuals with HIV or have a chronic disease.
A case study detailed the introduction of probiotic yogurt, made by local women in a low-income community in Tanzania, was significantly associated with an increase in immune cell count among consumers living with HIV.
Another study suggested that pre- and probiotics provided an ‘exciting adjunctive therapeutic approach for HIV infection’ that proved to be well-tolerated and inexpensive.
In the study, the researchers examined the gut microbiome, paying particular attention to protein creation and metabolite build up inside the bacteria as well as bacteria levels in the bloodstream, gastrointestinal tract, and faecal matter of HIV+ patients.
In total, eight healthy individuals served as controls and 29 HIV-infected individuals made up the test subjects.
The team found HIV infection to be linked to changes in the gut bacteria. Bacteria from the Acidaminococcaceae family were identified as an active biomarker of HIV infection.
In addition, three additional biomarkers for the HIV group were identified - the Clostridiaceae, Bifidobacteriaceae and Ruminococcaceae families, which, in contrast were significantly decreased in numbers amongst the HIV-infected patients.
“In this study we have found that, in some patients, certain gut bacteria become activated during ART and begin to amass anti-inflammatory molecules,” said Ferrer.
“The immune recovery of these ‘ART responders,’ is much better than that of their peers, the make-up and behaviour of whose gut bacteria does not lead to the same anti-inflammatory effect.”
Gut bacterial influence
In trying to explain how the gut bacteria interacted with the status of HIV-infected individuals, the team thought that HIV infection itself did not alter the function of the gut ecosystem but rather activate increased activity in a certain type of bacteria.
When looking at patients receiving antiretroviral therapy, whatever the level of immune recovery, these patents had the highest and most similar active bacterial richness and lowest evenness.
“It is possible that the reason why some subjects respond better to antiretrovirals is because their immune system is predisposed to these beneficial, recovery-enabling bacteria,” added researcher Sergio Serrano-Villar at Hospital Ramón y Cajal.
Published online ahead of print, doi.org/10.1016/j.ebiom.2016.04.033
“Gut Bacteria Metabolism Impacts Immune Recovery in HIV-infected Individuals.”
Authors: Andrés Moya et al.