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.

Prophylactic Use of Negative Pressure Therapy in General Abdominal Surgery: A Systematic Review and Meta-Analysis.

Background: Surgical site infections (SSIs) represent an economic burden to healthcare systems. The use of negative pressure wound therapy (NPWT) for SSI prophylaxis remains uncertain. Methods: A systematic literature search was conducted in Medline/PubMed, CINAHL, and Web of Science for relevant studies. The primary outcome was the evaluation of the effectiveness of NPWT for prophylaxis of SSI rates in general abdominal surgery. Secondary outcomes were rates of seroma and wound dehiscence, length of hospital stay, and re-admission rates. The statistical analysis was performed with random effect models. Results: A total of 3,193 patients from 20 articles (six randomized controlled trials [RCT], three prospective, eight retrospective, and three ambispective studies) were analyzed. Negative pressure wound therapy was associated with decreased rate of SSIs compared with standard dressing in a pooled analysis of non-randomized studies and RCTs (0.57; 95% confidence interval [CI], -0.4 to 0.8; p < 0.001). This result, however, needs to be challenged because of a significant statistical heterogeneity of the included studies (I2 = 71%; p < 0.01). A separate analysis of the six RCTs failed to confirm the superiority of NPWT (0.64; 95% CI, -0.4 to 1.04; p = 0.07), also disclosing significant heterogeneity. The analysis of secondary outcomes was only possible in combination of randomized and non-randomized studies because of incomplete datasets in RCTs. Re-admission rates were lower after NPWT and no difference was observed for the incidence of seroma, wound dehiscence, and length of hospital stay. Conclusions: Based on available evidence, the routine use of NPWT for SSI prophylaxis after laparotomy in general abdominal surgery cannot be generally recommended.