(P20-002-23) Intestinal Microbiome, Fecal Fermentation Profile, Fiber Intake, and Gut Permeability in HIV-infected Males Versus Non-infected Males

Objectives: Many HIV+ males on Highly Active Anti-Retroviral Therapy (HAART) experience metabolic abnormalities and gastrointestinal malabsorption. Dysbiosis of the microbiota is an imbalance of bacterial species through alteration of the number and distribution of microorganisms in the intestines, and the metabolism of accessible substrates indicated by the modification of the fecal fermentation profile. Products of fermentation of undigested intestinal contents by the gut bacteria produce short straight-chain fatty acids (SCFAs.) Studies of microbiome dysbiosis in HIV+ males on HAART show a signature Prevotella-rich enterotype. This study aimed to further elucidate the relationship between malabsorption in HIV+ males' gut microbiome and fermentation profiles, and serum markers of gut permeability in HIV-infected males.

Methods: This research enrolled 19 HIV+ males and 21 non-infected males. They were matched for age and body mass index (BMI). BMI and hip-to-waist ratio were obtained, along with blood collection. Stool was collected from each subject; a small aliquot was retained for microbiome analysis. The intestinal microbiome (16s rRNA) bacterial species identification and concentration was analyzed via Illumina genetic sequencing process, the fecal fermentation profile via gas chromatography. Serum markers for gut permeability, claudin, flagellin, and intestinal fatty acid binding protein 1 (IFABP-1), were analyzed via ELISA. Evaluation of dietary fiber intake using Validated Block 2014.1 1-month Food Frequency Questionnaire (FFQ).

Results: Significant differences were found between groups in SCFAs and microbiome profiles, with HIV+ males having significantly lower butyrate (p < 0.0013), isobutyrate (p < 0.0018), valeric (p < 0.0286), isovaleric (p < 0.0005), and acetate+propionate+butyrate (p < 0.0034). We identified a group of highly co-occurring taxa, including Prevotella, Alloprevotella,  and Libanococcus, which significantly increased HIV+ individuals (ANCOM W=80/117). There were no significant differences found between groups in gut permeability and dietary fiber.

Conclusions: HIV+ males have significant differences in the fecal fermentation profile and microbiome enterotype when compared to non-infected controls.

Funding Sources: Seed Grant, CEI, Infectious Disease and Immunity, ETSU