Thiamine deficiency underlies persistent gut dysbiosis and inflammation in people living with HIV on antiretroviral therapy

Abstract

Abstract Background Antiretroviral therapy (ART) has significantly improved the prognosis for people living with human immunodeficiency virus (PLWH). However, alterations in the gut microbiota of PLWH affect their metabolic environment and may contribute to chronic inflammation and premature aging, despite effective ART. Given that inflammation in the body have been shown to be risk factors for age-related diseases, elucidating changes in the gut microbiota and metabolic levels over time in individuals would be for understanding the dynamics in the body that lead to disease development. Methods The study assessed changes in blood markers, gut microbiota, and metabolic environment of PLWH on ART for four years, with participants divided into two groups based on median CD4 cell count (580/µL). Results The high-CD4 group was more obese than the low-CD4 group, but there was no significant difference in comorbidities, such as diabetes, hypertension, and dyslipidemia. An investigation of the alterations in gut microbiota over a 4-year period revealed a reduction in specific groups of bacteria that produce short-chain fatty acids (SCFAs) and an increase in the occurrence of Enterobacteriaceae. In addition, a decline in bacterial thiamine synthesis was predicted, and a decreased abundance of the Ruminococcus gauvreauii group, which relies on supplementation with thiamine from symbiotic bacteria, was observed. The abundance of Collinsella and Catenibacterium at baseline was positively correlated with the predicted number of thiamine-synthesizing pathway. The presence of Catenibacterium at follow-up was inversely correlated with the rate of increase in plasma levels of lipopolysaccharide-binding protein, an indicator of a leaky gut. In terms of assessing the diversity of gut microbiota, a trend towards an increase in opportunistic bacteria with different genetic distances was observed in the high-CD4 group at follow-up. Conclusion These observations suggested that, despite effective ART, the thiamine-deficient environment in the gut continues to reduce thiamine-requiring bacteria, such as certain SCFA-producing bacteria. As a result, secondary effects, such as proliferation of opportunistic bacteria and chronic inflammation associated with increased intestinal permeability, proceed in PLWH. Thus, certain essential nutrient deficiencies for gut metabolic environment may disrupt the symbiotic relationship between gut bacteria and increase the risk of developing inflammatory diseases.

Keywords

• Human immunodeficiency virus
• Gut microbiota
• Chronic inflammation
• Vitamin
• Antiretroviral therapy