Enalapril decreases rat plasma concentration of TMAO,a gut bacteria-derived cardiovascular marker

Introduction: Increased plasma level of trimethylamine N-oxide (TMAO), a bacterial metabolite of choline, is associated with an increased cardiovascular risk. Indoxyl sulfate, a bacterial metabolite of tryptophan, is thought to be associated with higher mortality in cardiorenal syndrome. We hypothesized that enalapril, a well-established drug reducing cardiovascular mortality, may affect the plasma level of gut bacteria-derived metabolites and gut bacteria composition.

Materials and methods: 14–16-week-old Wistar rats were maintained either on water (controls) or water solution of enalapril for two weeks (5.3 or 12.6?mg/kg b.w.). Blood plasma and urine were analyzed for the concentration of TMAO and indoxyl sulfate using liquid chromatography coupled with triple-quadrupole mass spectrometry. Gut bacteria composition was analyzed with 16S rRNA gene sequence analysis.

Results: Rats treated with enalapril showed a significantly lower plasma TMAO level and a trend towards higher 24?h urine excretion of TMA and TMAO. Plasma indoxyl level was similar between the groups. There was no significant difference between the groups in gut bacteria composition.

Conclusions: Enalapril decreases rat plasma TMAO, but does not affect the plasma level of indoxyl sulfate and gut bacteria composition. The enalapril-induced decrease in plasma TMAO level may be of therapeutic and diagnostic importance.