Effect of pioglitazone therapy on myocardial and hepatic steatosis in insulin-treated patients with type 2 diabetes

High levels of myocardial and hepatic triglyceride are common in obesity and type 2 diabetes. Monotherapy with thiazolidinedione agents reduces hepatic steatosis by up to 50% in patients with type 2 diabetes. It is not known if treatment with a thiazolidinedione added to insulin has a similar beneficial antisteatotic effect. The aim of our study was to determine whether the addition of pioglitazone to insulin treatment in patients with type 2 diabetes has antisteatotic action in the heart and the liver. Thirty-two patients were randomized to 6 months of treatment with insulin or insulin plus pioglitazone. In addition to blood tests, we evaluated myocardial and hepatic triglyceride content, as well as subcutaneous and visceral fat mass at the L2 level, by magnetic resonance spectroscopy and imaging, respectively. Despite weight and subcutaneous fat mass gain, hemoglobin A_1c was significantly reduced by both treatments. Myocardial and hepatic triglyceride contents were reduced by the treatment with pioglitazone plus insulin (p = .02 and .03, respectively) but not by the treatment with insulin. Systolic and diastolic blood pressure and heart function remained unchanged in both groups. The addition of pioglitazone to insulin therapy reduced myocardial and hepatic steatosis, consistent with the reported ability of the thiazolidinedione agents to redistribute fat from nonadipose to subcutaneous adipose depots.