Changes Of Fat Distribution And Insulin Resistance Following Laparoscopic Roux-en-Y Gastric Bypass In Patients With Type2Diabetes

objective:To observe the changes of fat distribution and insulin resistance before and after laparoscopic Roux-en-Y gastric bypass surgery (LRYGB) in patients with type2diabetes(T2DM)and to explore the relationship between the postoperative changes in fat distribution and insulin resistance.Methods:All the parameters including the plasma level of fasting glucose(FPG),fasting insulin(FINS),glycated hemoglobin(HbA1c),and lipids were measured in Twenty-one patients with type2diabetes before and after gastric bypass surgery. IR index was determined using the homeostasis model assessment of insulin resistance (HOMA-IR). Body composition and fat distribution were measured by dual-energy X-ray absorptiometry(DEXA). Fat mass (FM), muscle mass (MM),bone mineral content (BMC), and percent fat mass (%FM) at the whole body and five body regions including the arms, legs, trunk, android, and gynoid were obtained from DEXA scans.Results:(1) Postoperative oral hypoglycemic drugs type and the number of insulin users were significantly reduced compared with that preoperatively(P<0.05),and the proportion of patients with fatty liver and obstructive sleep apnea syndrome were reduced from66.7%to42.9%and19.0%to19.0%, respectively.(2) There was a statistically significant reduction in weight, BMI,WC and WHR Postoperatively (P<0.01).In addition, postoperative FPG, fasting C-peptide, HbAlc, HOMA-IR, TG, and CHOL were significantly decreased in comparison to the preoperative level(P<0.01).(3) Significant reduction in postoperative total fat mass (26.10±3.16vsl8.65±1.51kg;p<0.05),%FM at the whole body (31.43±8.44vs25.48±7.10;p<0.05) and other tested body region were noted(all p<0.05).FM change percent showed trunk> leg> arm (56.83%>30.26%>12.33%).Fat mass and the percentage of fat mass of android and gynoid region decreased significantly after surgery (p<0.05), the descent rate of android fat mass was greater than that in gynoid region (17.45±6.19%vs13.60±2.65%,p<0.05).(4) Changes in total body FM and android FM showed significant correlations with changes in HOMA-IR(r=0.48, r=0.55; p<0.05).Conclusions:Total body fat mass and fat mass in different region of T2DM patients reduced after LRYGB. Fat mass loss of trunk took over most part of total decreased fat mass. Changes in android FM may result in improvement of insulin resistance.