Quantifying Hepatic Mitochondrial Fluxes in Humans

The study team will examine hepatic mitochondrial TCA flux and pyruvate cycling (oral [U-13C]-propionate), hepatic gluconeogenesis (oral 2H2O), and hepatic insulin sensitivity (intravenous [3,4-13C2]-glucose with euglycemic insulin clamp) before and after 16 weeks treatment with the FDA approved insulin sensitizer pioglitazone. These studies will be performed in (i) type 2 diabetic subjects with NAFL but without evidence of fibrosis, and (ii) type 2 diabetic patients with NASH. Liver biopsies will be obtained before and after treatment for the diagnosis of NAFL/NASH and for molecular analyses.

T2D with NAFL

Inclusion criteria

• Confirmed T2D based on OGTT (2 h glucose ≥200 mg/dl).
• Treated with diet, metformin, and/or sulfonylurea and in good general health determined by medical history, physical exam, and routine blood chemistries;
• age = 18-80 years;
• BMI = 25-40 kg/m2;
• HbA1c = 7-10%; stable body weight (±4 pounds) over the preceding 3-months;
• not taking any medication known to affect glucose metabolism other than antidiabetic medications.
• Evidence of moderate/severe fatty liver (steatosis; grade S2/S3 on FibroScan corresponding to ≥10% fat on MRI-PDFF) and no/minimal hepatic fibrosis (grade F0/F1 on FibroScan).

Exclusion criteria

• Alcohol consumption >14 units/week for women and >21 units/week for men.
• Cirrhosis (fibrosis stage 4).
• Type 1 diabetes and/or GAD positive subjects.
• Subjects not drug naive or have been on metformin more than 3 months.
• Presence of proliferative retinopathy.
• Urine albumin excretion > 300 mg/day.
• Evidence of other forms of chronic liver disease, including alcoholic liver disease, hepatitis B and C, primary biliary cholangitis, suspected/proven liver cancer and any other liver disease other than NAFLD.
• History of NY Class III-IV heart failure

T2D with NASH

Inclusion criteria

• Confirmed T2D based on OGTT (2 h glucose ≥200 mg/dl).
• Treated with diet, metformin, and/or sulfonylurea and in good general health determined by medical history, physical exam, and routine blood chemistries;
• age = 18-80 years;
• BMI = 25-40 kg/m2;
• HbA1c = 7-10%;
• stable body weight (±4 pounds) over the preceding 3-months;
• not taking any medication known to affect glucose metabolism other than antidiabetic medications.
• Evidence of moderate/severe fatty liver (steatosis; grade S2/S3 on FibroScan corresponding to ≥10% liver fat on MRI-PDFF) and moderate/severe hepatic fibrosis (grade F2/F3 on FibroScan).

Exclusion criteria

• Alcohol consumption >14 units/week for women and >21 units/week for men.
• Cirrhosis (fibrosis stage 4).
• Type 1 diabetes and/or GAD positive subjects.
• Subjects not drug naive or have been on metformin more than 3 months.
• Presence of proliferative retinopathy.
• Urine albumin excretion > 300 mg/day.
• Evidence of other forms of chronic liver disease, including alcoholic liver disease, hepatitis B and C, primary biliary cholangitis, suspected/proven liver cancer and any other liver disease other than NAFLD.
• History of NY Class III-IV heart failure