Insulin resistance, but not insulin response, during oral glucose tolerance test (OGTT) is associated to worse histological outcome in obese NAFLD.

BACKGROUND AND AIM: Obese subjects are at high risk of nonalcoholic fatty liver disease (NAFLD) and diabetes (T2D) due to insulin resistance (IR). Since high glucose levels are as toxic as lipids for hepatic metabolism, we hypothesize that altered response to oral glucose tolerance test (OGTT) is associated to more severe NAFLD with significant/advanced liver damage. METHODS AND RESULTS: We studied 90 subjects with morbid obesity (73F/17M, BMI = 43.2 ± 5,9 kg/m2) undergoing bariatric surgery and intraoperative liver biopsy, and measured HbA1c, HOMA-IR (fasting Glucose x Insulin/22.5), OGTT glucose and insulin profile, and calculated OGIS (muscle insulin sensitivity), hepatic-IR (glucose [AUC0-30] x insulin [AUC0-30]) during OGTT, insulin response as (insulin [dAUC0-120]/glucose [dAUC0-120] or Insulinogenic Index (IGI = (I30-I0)/(G30-G0)). Patients were divided in 3 groups according to liver biopsy: A (no-NAFLD, 23%), B (simple steatosis (SS), 53%) and C (NASH, 24%) with similar age, gender and BMI. Diabetes was 0% in no-NAFLD, 13% in SS, 35% in NASH. During OGTT, OGIS decreased from A to C (422 vs 360 vs 338, p < 0.01). Increased insulin concentrations, HbA1c, HOMA-IR and OGIS, not Hep-IR, were strongly associated to hepatic steatosis (p = 0.03, p = 0.0001 and p = 0.01 respectively). Hepatic fibrosis stage was mild as most of the patients had fibrosis grade-1 (69% vs. 8% no fibrosis) and associated to fasting insulin, HbA1c and HOMA-IR. dAUC-I/dAUC-G was similar in the 3 groups, while only AUC-I was strongly associated to steatosis (r = 0.35, p = 0.005), but not to fibrosis. CONCLUSIONS: In morbid obesity indexes of IR, and not of insulin response, are markers of histological severity of liver disease.

Noninvasive assessment of hepatic steatosis and fibrosis in patients with severe obesity.

PURPOSE: In morbid obesity nonalcoholic fatty liver disease (NAFLD) is endemic. Aim of this study is to evaluate the diagnostic accuracy of the most common noninvasive methods for identify NAFLD and fibrosis in a cohort of morbid obese population. METHODS: Ninety morbid obese patients undergoing bariatric surgery (BS) and intraoperative liver biopsy were evaluated preoperatively with Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and serum biomarkers for steatosis and fibrosis and liver stiffness measurement (LSM) using acoustic radiation force impulse (ARFI) elastography. All nondiabetic patient (n = 77) underwent OGTT and calculation of Oral Glucose Insulin Sensitivity index (OGIS). RESULTS: In the entire cohort prevalence of NAFLD was 77%, NASH 24%, moderate/severe steatosis 50%, and significant fibrosis 14%. New cut-offs were evaluated for all steatosis score assessed in this population. In all patients with moderate/severe steatosis HOMA IR was significantly greater than 3.5. ALT, GGT, Triglycerides, HOMA IR, and ARFI increased with fibrosis grade (p 0.03, p 0.008, p 0.04, p 0.05, respectively) and AST to Platelet ratio (APRI) was the only noninvasive fibrosis score significantly increased in significant fibrosis (p 0.04). A combination of 1/OGIS and VAI was able to discriminate NASH from simple steatosis (NAFL) (p 0.02). CONCLUSIONS: In morbid obese subjects, we calculated new cut-offs of the most common steatosis indexes and found that a score based on insulin resistance (1/OGIS) and abdominal obesity (VAI) could represent a way to identify morbid obese subjects at risk of NASH.

Long-term Metabolic Effects of Laparoscopic Sleeve Gastrectomy.

OBJECTIVE: Obesity is one of the major health challenges throughout the world. The association between obesity and diabetes is well established because 90% of patients with type 2 diabetes mellitus (T2DM) show excess body weight. The aim of the study was to evaluate the effect of laparoscopic sleeve gastrectomy (LSG) on morbid obesity and type 2 diabetes (T2DM) in the long-term follow-up. METHODS: One hundred ninety-five obese patients, 78 with T2DM, were evaluated before and after LSG up to 10 years, to identify complete diabetes remission (FPG < 100 mg/dl, A1c < 6.0%), partial remission (FPG 100-125 mg/dl, A1c < 6.5%), or relapse. RESULTS: Before surgery, body weight and BMI were 123 ± 21 kg and 44.6 ± 6.8 kg/m2 respectively; at a mean follow-up of 7 years (range 4-10), body weight was 104.9 ± 18 kg and BMI 37 ± 6 kg/m2. Minimum weight was reached after 2 years. T2DM remission was observed in 66, 57, and 52% at short (< 2 years), medium (2-5 years), and long-term (> 5 years) follow-up respectively. Furthermore, 45.2% maintained complete remission for at least 5 years and about 36% showed a persistent but improved diabetes. None of the patients cured from diabetes had a duration disease greater than 8 years and a glycemic control requiring insulin. The prevalence of hypertension and dyslipidemia significantly decreased from 49 to 35% and from 51 to 40% respectively. CONCLUSIONS: LSG significantly improves body weight, diabetes, hypertension, and dyslipidemia in long-term follow-up.