The effects of incretin mimetics on the level of the microbial metabolite trimethylamine-N-oxide, a marker of cardiovascular risk in type 2 diabetic patients

Abstract

Background. The purpose was to investigate the effect of therapy with glucagon-like peptide-1 receptor agonists (GLP-1ra) on the serum concentration of trimethylamine-N-­oxide (TMAO), an intestinal microbiome metabolite, in patients with type 2 diabetes mellitus (T2DM) in relation to clinical and laboratory indicators and parameters of body composition. Materials and methods. Thirty-three T2DM patients (17 women and 16 men) were examined aged 31 to 72 years who had unsatisfactory control of carbohydrate metabolism (HbA1c > 7.4 %) against the background of previous glucose-lowering therapy (metformin, sulfonylurea derivatives, insulin, gliflozin) and were administered GLP-1ra. Before the start of treatment and after 6 months of therapy, parameters of anthropometry, body composition were measured (using the bioelectrical impedance analysis with the Tanita analyzer); blood glucose and glycated hemoglobin, TMAO concentration, blood lipids were assessed. Results. Patients diagnosed with Т2DM had HbA1c > 7.4 %; 91 % had general obesity (body mass index 34.7 ± 6.6 kg/m2), 100 % had abdominal obesity (waist circumference 118.00 ± 11.24 cm, Med ± SD). In 72 % of cases, there was a history of cardiovascular complications (myocardial infarction, stroke, coronary and peripheral atherosclerosis, arterial stenosis). Under the influence of a 6-month administration of GLP1ra, there was a decrease in the degree of total and abdominal obesity, a significant drop in the percentage of fat and the level of visceral fat, which was accompanied by an increase in hydration, a reduction in triglyceridemia and the concentration of very-low-density lipoprotein cholesterol (VLDL-C). A significant decrease in the level of TMAO microbial metabolite in the blood serum was recorded, which may reflect the antiatherogenic effect of GLP1ra, associated with the control of cholesterol and bile acid metabolism, the stimulation of VLDL-C receptors, and the effect on the secretion of insulin, glucagon, ghrelin, leptin, incretins. Conclusions. A study on the clinical effects of the incretin mimetic (GLP-1ra) in patients with T2DM confirmed its positive impact on glucose metabolism and blood lipids. At the same time, during GLP-1ra therapy, an improvement of some compositional and lipid indicators (visceral fat, triglycerides, VLDL-C) was recorded with a simultaneous decrease in the concentration of TMAO toxic metabolite.