Conditions: Diabetes Mellitus, Type 2
Keywords: Diabetes Mellitus, Type 2 Congestive Heart Failure Cardiopulmonary exercise testing intracellular cardiomyocyte triglycerides thiazolidinedione rosiglitazone nuclear magnetic resonance
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 150
Healthy volunteers: no

Brief summary:
The purpose of this study is to determine if rosiglitazone treatment improves integrated cardiovascular performance in patients at risk for congestive heart failure. A second aim of this study is to determine if treatment with rosiglitazone decreases intracellular (ectopic) triglyceride (TG) deposition in cardiomyocytes using nuclear magnetic resonance (NMR) techniques, and how changes in intra-myocardial lipid content relate to changes in cardiac structure and function.

Detailed description:
Cardiovascular disease (CVD), including congestive heart failure (CHF), accounts for over 75% of deaths among patients with diabetes. Thus, it is imperative to rigorously evaluate existing and emerging hypoglycemic therapies with regard to their cardiovascular consequences. The thiazolidinedione (TZD) class of drugs, alone or in combination with other oral hypoglycemic medications or with insulin, has emerged as a safe and effective treatment of hyperglycemia in type 2 diabetes. Both in vitro and in vivo studies have revealed favorable pleiotropic effects of TZD on myocyte and ventricular structure and function. However, approximately 10% of patients taking TZDs develop peripheral edema and some patients have developed heart failure decompensation on the drug. These observations have led to a Food and Drug Administration (FDA) warning regarding the use of TZDs in patients with or at high risk of developing congestive heart failure (CHF). The exact effects of TZDs on integrated cardiovascular performance remain unclear. The primary hypothesis of this study is that TZD treatment improves integrated cardiovascular performance in patients at risk for CHF by improving both central (i.e. cardiac output) and peripheral (i.e. vascular resistance) function.

Recently, we have developed a sensitive, reproducible noninvasive assay to measure intra-cardiomyocyte fat, which varies widely in amount between individuals. The relationship between the amount of cardiomyocyte triglyceride accumulation and LV mass and function remains unclear. TZDs have been previously shown to be associated with decreases in the TG content of the liver and muscle. The secondary hypothesis being tested in this study is that TZD treatment improves cardiac function by decreasing intra-cardiac myocyte triglyceride content.

Comparisons:

* Peak oxygen uptake (VO2) during cardiopulmonary exercise testing in individuals randomized to rosiglitazone, compared to those on placebo.
* Amount of intra-myocardial triglycerides using NMR techniques in in individuals randomized to rosiglitazone, compared to those on placebo.

Arms:
arm 1: 4mg titrated to 8mg daily arm 2: blinded matching placebo treatment

Interventions: intervention 1: rosiglitazone intervention 2: placebo
Intervention descriptions: intervention 1: 6 months of treatment of blinded study drug intervention 2: blinded treatment with matching placebo

Protocol document: