Increased Trimethylamine-N-Oxide (TMAO) Levels After Roux-en Y Gastric Bypass Surgery—Should We Worry About It?

Excerpt

The beneficial effects of Roux-en Y gastric bypass (RYGB) surgery, i.e., one of the most frequently performed bariatric procedures, have been well documented in patients suffering from severe obesity. Apart from improving quality of life, it has been shown that RYGB reduces overall and cardiovascular mortality as well as the rate of major cardiovascular events in large-scale retrospective case-control studies [1‐3] and several meta-analyses [4, 5]. It is commonly assumed that these beneficial effects of the surgery derive from its improving influence on glucose and lipid metabolism, blood pressure, and many other cardiovascular risk factors [6‐8]. A plethora of the metabolic effects of RYGB have been described, but there is still a need to comprehensively capture the metabolic processes that are affected by the surgery. Recently, a series of explorative studies applying untargeted metabolomic analyses on human [9, 10] and rat [11, 12] blood and urine samples obtained before and after the surgery have been performed and provided many interesting new insights on metabolic pathways altered by RYGB. One of these may deserve particular attention, i.e., the consistently found increase in trimethylamine-N-oxide (TMAO) blood and urine concentrations after the surgery [9‐13]. …