Biliopancreatic diversion in patients with type 2 diabetes and moderate obesity: impact and mechanisms.

Context Diabetes remission is frequent after biliopancreatic diversion (BPD) in morbidly obese patients with type 2 diabetes (T2DM). Data, mechanisms, and clinical indications in nonobese T2DM patients are scanty. Objective To assess remission and investigate insulin sensitivity and ß-cell function after BPD in non-morbidly obese patients with long-standing T2DM. Design, setting and patients Clinical research study comparing 15 T2DM patients (age 551 years, duration 16±2 years, BMI=28.3±0.6 kg/m2, HbA1c=8.6±1.3%) with 15 gender-, age-, and BMI-matched nondiabetic controls. Before surgery, and 2 months and one year later, a 3-hour OGTT, a 5-hour mixed meal test, and a 3-hour euglycemic clamp were performed. Intervention BPD (gastric resection, distal jejunum anastomosed to remaining stomach, biliopancreatic tract anastomosed to ileum 75cm from the ileocecal valve). Results Glycemia improved in all patients, but remission (HbA1c<6.5% and normal OGTT) occurred in 6/15. Insulin resistance (19.8±0.8 µmol.min-1.kgffm-1, p<0.001 vs 40.9±5.3 of controls) resolved already at 2 months (34.2±2.8) and was sustained at one year (34.7±1.6), although insulin-mediated suppression of endogenous glucose production remained impaired. In contrast, ß-cell glucose sensitivity (19[12] pmol.min-1.m-2.mM-1 vs 96[73] of controls, p<0.0001) rose (p=0.02) only to 31[26] at one year, and was lower in non-remitters (16[18]) than remitters (46[33]). Conclusions In nonobese patients with long-standing T2DM, BPD improves metabolic control but induces remission in only ~30% of patients. Peripheral insulin sensitivity is restored early after surgery, and similarly in remitters and non-remitters, indicating a weight-independent effect of the operation. The initial extent of ß-cell incompetence is the main predictor of the metabolic outcome

A specific gut microbiota signature is associated with an enhanced GLP-1 and GLP-2 secretion and improved metabolic control in patients with type 2 diabetes after metabolic Roux-en-Y gastric bypass

ObjectiveTo determine changes in incretins, systemic inflammation, intestinal permeability and microbiome modifications 12 months after metabolic RYGB (mRYGB) in patients with type 2 diabetes (T2D) and their relationship with metabolic improvement.Materials and methodsProspective single-center non-randomized controlled study, including patients with class II-III obesity and T2D undergoing mRYGB. At baseline and one year after surgery we performed body composition measurements, biochemical analysis, a meal tolerance test (MTT) and lipid test (LT) with determination of the area under the curve (AUC) for insulin, C-peptide, GLP-1, GLP-2, and fasting determinations of succinate, zonulin, IL-6 and study of gut microbiota.ResultsThirteen patients aged 52.6 ± 6.5 years, BMI 39.3 ± 1.4 kg/m2, HbA1c 7.62 ± 1.5% were evaluated. After mRYGB, zonulin decreased and an increase in AUC after MTT was observed for GLP-1 (pre 9371 ± 5973 vs post 15788 ± 8021 pM, P&lt;0.05), GLP-2 (pre 732 ± 182 vs post 1190 ± 447 ng/ml, P&lt;0.001) and C- peptide, as well as after LT. Species belonging to Streptococaceae, Akkermansiacea, Rickenellaceae, Sutterellaceae, Enterobacteriaceae, Oscillospiraceae, Veillonellaceae, Enterobacterales_uc, and Fusobacteriaceae families increased after intervention and correlated positively with AUC of GLP-1 and GLP-2, and negatively with glucose, HbA1c, triglycerides and adiposity markers. Clostridium perfringens and Roseburia sp. 40_7 behaved similarly. In contrast, some species belonging to Lachnospiraceae, Erysipelotricaceae, and Rumnicocaceae families decreased and showed opposite correlations. Higher initial C-peptide was the only predictor for T2D remission, which was achieved in 69% of patients.ConclusionsPatients with obesity and T2D submitted to mRYGB show an enhanced incretin response, a reduced gut permeability and a metabolic improvement, associated with a specific microbiota signature

Decreased expression of hepatic glucokinase in type 2 diabetes

Background/objectives: Increased endogenous glucose production is a hallmark of type 2 diabetes. Evidence from animal models has suggested that a likely cause of this is increased mRNA expression of glucose 6-phosphatase and phosphoenolpyruvate carboxykinase (encoded by G6PC, PCK1 and PCK2). But another contributing factor may be decreased liver glucokinase (encoded by GCK). Methods: We examined expression of these enzymes in liver biopsies from 12 nondiabetic and 28 diabetic individuals. Diabetic patients were further separated into those with HbA1c lower or higher than 7.0. Results: In diabetic subjects with HbA1c > 7.0, we found that gluconeogenic enzymes were expressed normally, but GCK was suppressed more than 60%. Moreover, HbA1c and fasting glucose were negatively correlated with GCK, but showed no correlation with G6PC, PCK1, or PCK2. Conclusion: These findings suggest an underlying dysregulation of hepatic GCK expression during frank diabetes, which has implications for the therapeutic use of glucokinase activators in this population

Increased bile acid synthesis and deconjugation after Biliopancreatic diversion

Biliopancreatic diversion (BPD) improves insulin sensitivity and decreases serum cholesterol out of proportion with weight loss. Mechanisms of these effects are unknown. One set of proposed contributors to metabolic improvements after bariatric surgeries is bile acids (BAs). We investigated the early and late effects of BPD on plasma BA levels, composition, and markers of BA synthesis in 15 patients with type 2 diabetes (T2D). We compared these to the early and late effects of Roux-en-Y gastric bypass (RYGB) in 22 patients with T2D and 16 with normal glucose tolerance. Seven weeks after BPD, insulin sensitivity had doubled and serum cholesterol had halved. At this time, BA synthesis markers and total plasma BAs, particularly unconjugated BAs, had markedly risen; this effect could not be entirely explained by low FGF19. In contrast, after RYGB, insulin sensitivity improved gradually with weight loss and cholesterol levels declined marginally; BA synthesis markers were decreased at an early time point (2 weeks) after surgery and returned to the normal range 1 year later. These findings indicate that BA synthesis contributes to the decreased serum cholesterol after BPD. Moreover, they suggest a potential role for altered enterohepatic circulation of BAs in improving insulin sensitivity and cholesterol metabolism after BPD