Rosiglitazone Improves Exercise Capacity in Individuals With Type 2 Diabetes
- Judith G. Regensteiner, PHD1,
- Timothy A. Bauer, MS1 and
- Jane E.B. Reusch, MD2
- 1Divisions of Internal Medicine and Cardiology and the Center for Women’s Health Research, Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado
- 2Division of Endocrinology and the Center for Women’s Health Research, Department of Medicine, University of Colorado Health Sciences Center, Veterans Administration Medical Center, Denver, Colorado
- Address correspondence and reprint requests to Judith G. Regensteiner, PhD, Professor of Medicine, Box B-180, University of Colorado Health Sciences Center, 4200 E. 9th Ave., Denver, CO 80262. E-mail: judy.regensteiner{at}uchsc.edu
Abstract
OBJECTIVE—Although exercise is recommended as a cornerstone of treatment for type 2 diabetes, it is often poorly adopted by patients. We have noted that even in the absence of apparent cardiovascular disease, persons with type 2 diabetes have an impaired ability to carry out maximal exercise, and the impairment is correlated with insulin resistance and endothelial dysfunction. We hypothesized that administration of a thiazolidinedione (TZD) agent would improve exercise capacity in type 2 diabetes.
RESEARCH DESIGN AND METHODS—Twenty participants with uncomplicated type 2 diabetes were randomly assigned in a double-blind study to receive either 4 mg/day of rosiglitazone or matching placebo after baseline measurements to assess endothelial function (brachial artery diameter by brachial ultrasound), maximal oxygen consumption ([Vdot]o2max), oxygen uptake ([Vdot]o2) kinetics, and insulin sensitivity by hyperinsulinemic-euglycemic clamp. Measurements were reassessed after 4 months of treatment.
RESULTS—Participant groups did not differ at baseline in any measure. Rosiglitazone-treated participants (n = 10) had significantly improved [Vdot]o2max (19.8 ± 5.3 ml · kg−1 · min−1 before rosiglitazone vs. 21.2 ± 5.1 ml · kg−1 · min−1 after rosiglitazone, P < 0.01), insulin sensitivity, and endothelial function. A change in [Vdot]o2max correlated with improved insulin sensitivity measured by clamp (r = 0.68, P < 0.05) and with improved brachial artery diameter (r = 0.70, P < 0.05). Placebo-treated participants (n = 10) showed no changes in [Vdot]o2max (19.4 ± 5.2 ml · kg−1 · min−1 before rosiglitazone vs. 18.1 ± 5.3 ml · kg−1 · min−1 after rosiglitazone, NS) or brachial artery diameter.
CONCLUSIONS—This is the first known report showing that a TZD improved exercise function in type 2 diabetes. Whether this is due to the observed improvements in insulin sensitivity and/or endothelial function or to another action of the TZD class requires further exploration.
- CWR, constant work rate
- DEXA, dual-energy X-ray absorptiometry
- HOMA-IR, homeostasis model assessment of insulin resistance
- TZD, thiazolidinedione
Footnotes
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A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
See accompanying editorial, p. 2975.
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- Accepted July 11, 2005.
- Received March 16, 2005.
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