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Different bariatric procedures have been associated with variable weight loss and decrease in serum levels of lipids and lipoproteins. This variation could be partly related to the length of the small intestinal bypass. We evaluated the association of the small intestinal length with the non-alcoholic fatty liver disease (NAFLD) at baseline and with lipid metabolism before and after laparoscopic Roux-en-Y gastric bypass (LRYGB). Seventy consecutive morbidly obese patients were recruited to this prospective study. A standard 60-cm biliopancreatic limb (BPL) and 120-cm alimentary limb (AL) was performed, and thereafter, the common channel (CC) length was measured during elective LRYGB. Histological analysis of liver biopsy to diagnose NAFLD was performed. The mRNA expression of genes participating in the cholesterol and fatty acid metabolism in the liver was analyzed. Female sex (p = 0.006), serum triglycerides (TG, p = 0.016), serum alanine aminotransferase (ALT, p = 0.007), and liver steatosis (p = 0.001) associated with the small intestinal length (BPL + AL + CC) at baseline. Association remained significant between levels of serum TG and CC length (p = 0.048) at 1-year follow-up. Liver mRNA expression of genes regulating cholesterol synthesis and bile metabolism did not associate with the baseline small intestinal length. Our findings support the suggestions that small intestinal length regulates TG metabolism before and after LRYGB. Therefore, modification of the length of bypassed small intestine based on measured total small intestinal length could optimize the outcomes of the elective LRYGB.

Laparoscopic Roux-en-Y gastric bypass (RYGB) induces a more favorable metabolic profile than expected by weight loss alone. In this study, we investigated the effect of RYGB on serum bile acid levels and their relation to clinical outcomes. We included 30 obese patients who underwent RYGB (BMI = 46.1 +/- 5.9 kg/m(2)). Clinical measurements and laboratory determinations were performed before surgery and 1 year after surgery. Fasting serum bile acids were measured by an enzymatic method and individual bile acids were quantified by HLPC-tandem mass spectrometry. Indirect calorimetry was performed to measure the rates of energy expenditure and substrate oxidation. Fasting total serum bile acid levels increased twofold after RYGB (pre, 3.68 +/- 2.03 vs. post, 7.06 +/- 9.65 mu mol/l, +92 %, p = 0.002). This increase in total bile acids was accompanied by a decrease in conjugated bile acids, which correlated with decreased glucose oxidation (r = 0.571, p = 0.002) and with increased lipid oxidation (r = -0.626, p = 0.0004). The change in taurine-conjugated bile acids correlated with altered DIO2 mRNA expression in adipose tissue (r = -0.498, p = 0.013) potentially linking bile acid conjugation to substrate oxidation through DIO2. Fasting serum bile acid levels increase after RYGB. More specifically, changes in bile acid conjugation after RYGB associate with altered energy metabolism.

We evaluated the benefit of using combined genetic risk score (GRS) of known single nucleotide polymorphisms (SNPs) for body mass index (BMI) and waist/hip ratio (WHR) in the prediction of weight loss and weight regain after obesity surgery.A total of 163 consecutive morbidly obese individuals undergoing Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) in a single bariatric center in Finland were recruited. Fasting blood samples were drawn after 12 h of fasting before and 1 year after bariatric operation. Data for weight regain and medication were collected with a questionnaire after 3.1 ± 2.7 years (mean ± SD) follow-up. Nonalcoholic steatohepatitis (NASH) was diagnosed with liver histology. Twenty BMI- and 13 WHR-related SNPs were genotyped. Linear regression was used to identify factors predicting weight loss and weight regain.Lower baseline BMI predicted greater decline in BMI (p = 0.0005) and excess weight loss (EWL) (p = 0.009). In the multiple linear regression analysis age and BMI, explained the variance of EWL during the first year while GRS, sex, fasting plasma glucose, serum insulin and NASH diagnosis did not have any effect. None of the baseline clinical variables explained BMI regain. The combined GRS did not associate with weight or BMI at baseline, with 1-year changes or with weight regain between 1 year and an average of 3.1 years follow-up.In our study, we found that the genotype risk score does not predict weight loss after obesity surgery while lower baseline BMI predicted the greater weight loss.