Skeletal muscle cellular metabolism in older HIV‐infected men. Issue 9 (10th May 2016)

• Record Type: Journal Article
• Authors: Ortmeyer, Heidi K.; Ryan, Alice S.; Hafer‐Macko, Charlene; Oursler, KrisAnn K.
• Is Part Of: Physiological reports. Volume 4:Issue 9(2016:May)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2016-05-10
• Subjects: Cardiolipin -- citrate synthase -- glycogen synthase -- hydrogen peroxide -- β‐hydroxy acyl‐CoA dehydrogenase; Physiology -- Periodicals; 571
• DOI: 10.14814/phy2.12794
• Languages: English
• ISSNs: 2051-817X

Abstract

Abstract: Skeletal muscle mitochondrial dysfunction may contribute to low aerobic capacity. We previously reported 40% lower aerobic capacity in HIV‐infected men compared to noninfected age‐matched men. The objective of this study was to compare skeletal muscle mitochondrial enzyme activities in HIV‐infected men on antiretroviral therapy (55 ± 1 years of age, n = 10 African American men) with age‐matched controls (55 ± 1 years of age, n = 8 Caucasian men), and determine their relationship with aerobic capacity. Activity assays for mitochondrial function including enzymes involved in fatty acid activation and oxidation, and oxidative phosphorylation, were performed in homogenates prepared from vastus lateralis muscle. Hydrogen peroxide (H2 O2 ), cardiolipin, and oxidized cardiolipin were also measured. β ‐hydroxy acyl‐CoA dehydrogenase ( β ‐HAD) (38%) and citrate synthase (77%) activities were significantly lower, and H2 O2 (1.4‐fold) and oxidized cardiolipin (1.8‐fold) were significantly higher in HIV‐infected men. VO2 peak (mL/kg FFM/min) was 33% lower in HIV‐infected men and was directly related to β ‐HAD and citrate synthase activity and inversely related to H2 O2 and oxidized cardiolipin. Older HIV‐infected men have reduced oxidative enzyme activity and increased oxidative stress compared to age‐matched controls. Further research is crucial to determine whether an increase in aerobic capacity by exercise training will be sufficient to restore mitochondrial function in older HIV‐infected individuals. Abstract : The objective of our study was to compare skeletal muscle mitochondrial enzyme activities in older HIV‐infected men to age‐matched controls. We found enzymes involved in fatty acid oxidation, glucose metabolism, and oxidative capacity to be lower in HIV‐infected men and hydrogen peroxide and oxidized cardiolipin to be higher in HIV‐infected men. These variables may contribute to lower VO2peak in HIV‐infected individuals.