Plasma short-chain fatty acid changes after bariatric surgery in patients with severe obesity.

BACKGROUND: Obesity has reached epidemic dimensions in recent decades. Bariatric surgery (BS) is one of the most effective interventions for weight loss and metabolic improvement in patients with obesity. Short-chain fatty acids (SCFA) are gut microbiota-derived metabolites with a key role in body weight control and insulin sensitivity. Although BS is known to induce significant changes in the gut microbiota composition, its impact on the circulating levels of certain metabolites produced by the gut microbiota such as SCFA remains poorly understood. OBJECTIVE: To determine the impact of BS on the circulating SCFA levels in patients with severe obesity. SETTING: University hospital. METHODS: An observational, prospective study was performed on 51 patients undergoing Roux-en-Y gastric bypass. Plasma samples were collected at baseline (1 day before surgery) and at 6 and 12 months after BS. Plasma SCFA levels were determined by liquid chromatography-mass spectrometry. RESULTS: The results revealed significant changes in the circulating levels of SCFA after BS. A marked increase in propionate, butyrate, isobutyrate, and isovalerate levels and a decrease in acetate, valerate, hexanoate, and heptanoate levels were observed 12 months after BS. Furthermore, the changes in the levels of propionate, butyrate, and isobutyrate negatively correlated with changes in body mass index, while those of isobutyrate correlated negatively with changes in the homeostatic model assessment for insulin resistance index. CONCLUSION: These results suggest that propionate, butyrate, and isobutyrate levels could be related to weight loss and improved insulin sensitivity in patients with severe obesity after BS.

Metabolism of different dietary phenolic compounds by the urolithin-producing human-gut bacteria Gordonibacter urolithinfaciens and Ellagibacter isourolithinifaciens.

Gordonibacter urolithinfaciens and Ellagibacter isourolithinifaciens are two human gut bacterial species that convert ellagic acid into urolithins. Urolithins are bioactive postbiotics produced by dehydroxylation reactions catalyzed by different catechol-dehydroxylases. The metabolic ability of these anaerobic bacteria on other dietary-phenolic compounds is unknown. In the present study, we evaluated the metabolism of flavonoids (quercetin, hesperetin, hesperidin, nobiletin, catechin, isoxanthohumol), isoflavonoids (daidzein), coumarins (esculetin, umbelliferone, scoparone), phenylpropanoids [caffeic acid; 3-(3',4'-dihydroxyphenyl)propanoic acid (dihydrocaffeic acid); rosmarinic acid, and chlorogenic acid], benzoic acid derivatives (gallic acid, ellagic acid), lignans (secoisolariciresinol diglucoside), stilbenes (resveratrol), and secoiridoids (oleuropein) by G. urolithinfaciens DSM 27213T and E. isourolithinifaciens DSM 104140T. Both strains metabolized ellagic acid leading to the characteristic urolithins. They also metabolized caffeic, dihydrocaffeic, rosmarinic, and chlorogenic acids. The rest of the phenolic compounds were not transformed. Catechol dehydroxylation and double bond reduction were prominent transformations observed during the incubations. The enzymatic activities seem to have a narrow substrate scope as many catechol- (quercetin, catechin, esculetin, gallic acid) and double bond-containing (resveratrol, esculetin, scoparone, umbelliferone) phenolics were not metabolized. The catechol-dehydroxylase activity was more efficient in E. isourolithinifaciens, while the reductase activity was more relevant in G. urolithinfaciens.

Modification of cardiometabolic profile in obese diabetic patients after bariatric surgery: changes in cardiovascular risk.

INTRODUCTION AND OBJECTIVES: Bariatric surgery is a valuable tool for metabolic control in obese diabetic patients. The aim of this study was to determine changes in weight and carbohydrate and lipid metabolism in obese diabetic patients during the first 4 years after bariatric surgery. METHODS: A retrospective study was performed in 104 patients (71 women; mean age, 53.0 [0.9] years; mean body mass index, 46.8 [0.7]) with type 2 diabetes mellitus (median duration, 3 years) who underwent laparoscopic proximal gastric bypass. RESULTS: Blood glucose levels and glycated hemoglobin concentrations decreased during the first 1-3 postoperative months. Values stabilized for the rest of the study period, allowing hypoglycemic treatment to be discontinued in 80% of the patients. No significant differences were observed as a function of the body mass index, diabetes mellitus duration, or previous antidiabetic treatment. Weight decreased during the first 15-24 months and slightly increased afterward. Levels of total cholesterol, triglycerides, and low-density lipoprotein significantly decreased, and target values were reached after 12 months in 80% of the patients. No correlation was found between these reductions and weight loss. Similarly, high-density lipoprotein concentrations decreased until 12 months after surgery. Although concentrations showed a subsequent slight increase, target or lower high-density lipoprotein values were achieved at 24 months postintervention in 85% of the patients. CONCLUSIONS: Bariatric surgery is effective for the treatment of obese diabetic patients, contributing to their metabolic control and reducing their cardiovascular risk.