1Division of Endocrinology, Diabetes and Metabolism, University of Florida, Gainesville, FL Department of Medicine, University of Florida, Gainesville, FL.
2Division of Endocrinology, Diabetes and Metabolism, University of Florida, Gainesville, FL.
3Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX.
4Department of Medicine, University of Florida, Gainesville, FL.
5Division of Gastroenterology, Hepatology, and Nutrition, Malcom Randall VA Medical Center, Gainesville, FL.
6Division of Pathology, Malcom Randall VA Medical Center, Gainesville, FL.
7Division of Endocrinology, Diabetes and Metabolism, University of Florida, Gainesville, FL Division of Endocrinology, Malcom Randall VA Medical Center, Gainesville, FL email@example.com.
Nonalcoholic steatohepatitis (NASH) is increasingly common in obese patients. However, its metabolic consequences in patients with type 2 diabetes mellitus (T2DM) are unknown.
RESEARCH DESIGN AND METHODS:
We studied 154 obese patients divided in four groups: 1) control (no T2DM or NAFLD), 2) T2DM without NAFLD, 3) T2DM with isolated steatosis, and 4) T2DM with NASH. We evaluated intrahepatic triglycerides by proton MRS (1H-MRS) and assessed insulin secretion/resistance during an oral glucose tolerance test and a euglycemic-hyperinsulinemic clamp with glucose turnover measurements.
No significant differences among groups were observed in sex, BMI, or total body fat. Metabolic parameters worsened progressively with the presence of T2DM and the development of hepatic steatosis, with worse hyperinsulinemia, insulin resistance, and dyslipidemia (hypertriglyceridemia and low HDL cholesterol) in those with NASH (P < 0.001). Compared with isolated steatosis, NASH was associated with more dysfunctional and insulin resistant adipose tissue (either as insulin suppression of plasma FFA [33 ± 3 vs. 48 ± 6%] or adipose tissue insulin resistance index [9.8 ± 1.0 vs. 5.9 ± 0.8 mmol/L ⋅ µIU/mL]; both P < 0.03). Furthermore, insulin suppression of plasma FFA correlated well with hepatic steatosis (r = -0.62; P < 0.001) and severity of steatohepatitis (rs = -0.52; P < 0.001). Hepatic insulin sensitivity was also more significantly impaired among patients with T2DM and NASH, both fasting and with increasing insulin levels within the physiological range (10 to 140 µIU/mL), compared with other groups.
In obese patients with T2DM, the presence of NAFLD is associated with more severe hyperinsulinemia, dyslipidemia, and adipose tissue/hepatic insulin resistance compared with patients without NAFLD. The unfavorable metabolic profile linked to NAFLD should prompt strategies to identify and treat this population early on.