Growth hormone treatment improves peripheral muscle oxygen extraction-utilization during exercise in patients with human immunodeficiency virus-associated wasting: a randomized controlled trial.
The arteriovenous oxygen difference (a-vO(2) 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-VO(2)) relationship. We investigated the impact of recombinant human GH (rhGH) treatment on a-vO(2) difference and the Q-VO(2) 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/m(2); maximum oxygen consumption, 33.6 +/- 1.5 ml/kg x min), with documented unintentional weight loss (>or=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 CO(2) rebreathing), and subsequently a-vO(2) difference, from Q-VO(2) relationships. At study entry, the mean slope (8.1 +/- 1.0 liters/min x 1-liter increase in VO(2)) and intercept (3.1 +/- 1.3 liters/min), generated from each patient's Q-VO(2) 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-vO(2) 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-vO(2) difference (at a VO(2) 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-VO(2) relationship during exercise in patients with HIV-associated wasting despite antiretroviral therapy.
Graduate Department of Rehabilitation Science, Faculty of Medicine, University of Toronto, Ontario, Canada M5G 1X5.
John G
JG
Esposito
Scott G
SG
Thomas
Lori
L
Kingdon
Shereen
S
Ezzat
D000328:Adult; D000368:Aged; D019380:Anti-HIV Agents / Q000008:administration & dosage; D001823:Body Composition; D004311:Double-Blind Method; D015444:Exercise; D005080:Exercise Test; D019247:HIV Wasting Syndrome / Q000188:drug therapy* / Q000378:metabolism*; D019382:Human Growth Hormone / Q000008:administration & dosage*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects*
D019380:Anti-HIV Agents; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I