Abstract 12480: Changes in Tmao Levels Following Bariatric Surgery Vary by Procedure Type

Abstract

Introduction: Trimethylamine-N-oxide (TMAO), a metabolite generated by the gut microbiota from dietary phosphatidylcholine and carnitine, is linked to atherosclerosis and thrombosis. Although bariatric surgery improves CV outcomes, several studies in both animals and humans have shown increased TMAO levels after bariatric surgery. We tested the impact of the two most common bariatric procedures on plasma TMAO. Methods: This study included 93 severely obese non-diabetic individuals who did not take diabetes or lipid-lowering medications and underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Plasma TMAO was measured before and ≥ six months after bariatric surgery. Results: Mean age of the subjects was 31.4 ± 7.2 years and 90% were female. At baseline, average weight and BMI were 117.1 ± 24.4 kg and 43.4 ± 8.0 kg/m 2 respectively. Average baseline plasma TMAO level was 2.2 ± 1.4 μM. 29 patients underwent RYGB and 64 patients underwent SG. There were no significant differences in baseline weight, BMI, or TMAO between procedures. RYGB patients lost significantly more weight than SG patients (37.5 ± 8.6 kg for RYGB vs 32.8 ± 9.0 kg for SG, p = 0.03). TMAO levels did not change following SG, whereas they increased after RYGB ( Figure ). Changes in TMAO were not associated with changes in other clinical measures, for example, body weight and BMI ( Figure ) for either RYGB or SG patients. Conclusions: We found contrasting responses in circulating TMAO following bariatric surgical procedures employing dissimilar anatomical alterations. Given TMAO-associated CVD risk, these differences may lead to contrasting CV outcomes in the future. Additional research to understand changes in TMAO and the microbiota after bariatric surgery, and their clinical relevance, are warranted.