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Growth Hormone Treatment Improves Peripheral Muscle Oxygen Extraction-Utilization during Exercise in Patients with Human Immunodeficiency Virus-Associated Wasting: A Randomized Controlled Trial

Graduate Department of Rehabilitation Science, Faculty of Medicine (J.G.E., S.G.T.); Graduate Department of Exercise Sciences, Faculty of Physical Education and Health (S.G.T.); and Department of Medicine, Faculty of Medicine (S.E.), University of Toronto; and Freeman Center of Endocrine Oncology, Mount Sinai Hospital (L.K., S.E.), Toronto, Ontario, Canada M5G 1X5

Address all correspondence and requests for reprints to: Dr. Shereen Ezzat, Mount Sinai Hospital, 600 University Avenue, #437 Toronto, Ontario, Canada M5G 1X5. E-mail: sezzat{at}mtsinai.on.ca.

The arteriovenous oxygen difference (a-vO₂ difference), a measure of peripheral muscle oxygen extraction-utilization during exercise, is reduced in antiretroviral-treated patients with human immunodeficiency virus (HIV), thus causing a shift in the cardiac output-oxygen consumption (Q-VO₂) relationship. We investigated the impact of recombinant human GH (rhGH) treatment on a-vO₂ difference and the Q-VO₂ relationship during submaximal exercise by randomizing 12 HIV-infected patients (mean ± SEM: age, 43.3 ± 1.5 yr; body mass, 69.5 ± 2.9 kg; body mass index, 22.4 ± 0.9 kg/m²; maximum oxygen consumption, 33.6 ± 1.5 ml/kg·min), with documented unintentional weight loss (10% within the preceding 12 months) despite antiretroviral therapy, to receive 3 months of rhGH (6 mg/d) in a double-blind, placebo-controlled, cross-over trial. We assessed Q (determined noninvasively using CO₂ rebreathing), and subsequently a-vO₂ difference, from Q-VO₂ relationships. At study entry, the mean slope (8.1 ± 1.0 liters/min·1-liter increase in VO₂) and intercept (3.1 ± 1.3 liters/min), generated from each patient’s Q-VO₂ relationship, were greater and lower, respectively, than those reported for healthy individuals (6.0 and 4.0, respectively), thereby indicating a deficit in the a-vO₂ difference. After 3 months of rhGH treatment, the slope decreased to 7.0, and the intercept increased to 3.5. After 1 month of rhGH treatment, the a-vO₂ difference (at a VO₂ of 1250 ml/min) significantly (P < 0.05) increased (17.1 ± 8.9%) from baseline (9.92 ± 0.51 ml/dl) and remained elevated (10.39 ± 0.48 ml/dl) after 3 months of treatment. No significant changes were seen with placebo. Therefore, treatment with rhGH leads to an improvement in peripheral muscle oxygen extraction-utilization and the Q-VO₂ relationship during exercise in patients with HIV-associated wasting despite antiretroviral therapy.

This article has been cited by other articles:

				J. G. Esposito, S. G. Thomas, L. Kingdon, and S. Ezzat Anabolic growth hormone action improves submaximal measures of physical performance in patients with HIV-associated wasting Am J Physiol Endocrinol Metab, September 1, 2005; 289(3): E494 - E503. [Abstract] [Full Text] [PDF]