Serum trimethylamine-N-oxide concentrations in people living with HIV and the effect of probiotics supplementation

Abstract Background: Cardiovascular disorders show a higher incidence in people living with HIV (PLWH). Traditional and specific risk factors have been described but the role of the gut microbiota-dependent choline metabolite trimethylamine-N-oxide (TMAO) is still unclear. Methods: A cross-sectional analysis and a longitudinal analysis (with high-dose probiotics supplementation) were performed measuring serum TMAO concentrations through UHPLC- MS/MS. Stable outpatients living with HIV on highly active antiretroviral treatment with no major cardiovascular disease were enrolled. Non parametric tests (bivariate and paired tests) and a multivariate linear regression analysis were used. Results: In 175 participants serum TMAO concentrations were 165 ng/mL (103-273). An association with age, serum creatinine, number of antiretrovirals, multimorbidity and polypharmacy was observed: at linear logistic regression analysis, multimorbidity was theonly independent predictor of TMAO concentrations. Carotid intima media thickness (IMT) was 0.85 mm (0.71-1.21); we observed a trend towards higher TMAO concentrations in patients with IMT >0.9 mm (p=0.087). In the 25 participants who received probiotic supplementation, TMAO levels did not significant changed after 24 weeks (Wilcoxon paired p 0.220). Conclusion: Serum TMAO levels in PLWH are associated with multimorbidity, higher cardiovascular risk and subclinical atherosclerosis; no effect of six months of high-dose probiotics supplementation was observed.