title: Lower aerobic capacity was associated with abnormal intramuscular energetics in patients with metabolic syndrome.
abstract: Lower aerobic capacity is a strong and independent predictor of cardiovascular morbidity and mortality in patients with metabolic syndrome (MetS). However, the mechanisms are not fully elucidated. We tested the hypothesis that skeletal muscle dysfunction could contribute to the lower aerobic capacity in MetS patients. The incremental exercise tests with cycle ergometer were performed in 12 male patients with MetS with no habitual exercise and 11 age-, sex- and activity-matched control subjects to assess the aerobic capacity. We performed (31)phosphorus-magnetic resonance spectroscopy (MRS) to assess the high-energy phosphate metabolism in skeletal muscle during aerobic exercise. Proton-MRS was also performed to measure intramyocellular lipid (IMCL) content. Peak oxygen uptake (peak VO(2); 34.1±6.2 vs. 41.4±8.4 ml kg(-1) min(-1), P<0.05) and anaerobic threshold (AT; 18.0±2.4 vs. 23.1±3.7 ml kg(-1) min(-1), P<0.01) adjusted by lean body mass were lower in MetS patients than control subjects. Phosphocreatine (PCr) loss during exercise was 1.5-fold greater in MetS, suggesting reduced intramuscular oxidative capacity. PCr loss was inversely correlated with peak VO(2) (r=-0.64) and AT (r=-0.60), respectively. IMCL content was threefold higher in MetS and was inversely correlated with peak VO(2) (r=-0.47) and AT (r=-0.52), respectively. Moreover, there was a positive correlation between IMCL content and PCr loss (r=0.64). These results suggested that lean-body aerobic capacity in MetS patients was lower compared with activity-matched healthy subjects, which might be due to the reduced intramuscular fatty acid oxidative metabolism.
authors.affiliation: Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yokota
authors.forename: Shintaro
authors.initials: S
authors.lastname: Kinugawa
authors.forename: Koichi
authors.initials: K
authors.lastname: Okita
authors.forename: Kagami
authors.initials: K
authors.lastname: Hirabayashi
authors.forename: Tadashi
authors.initials: T
authors.lastname: Suga
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hattori
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Nakagawa
authors.forename: Noriko
authors.initials: N
authors.lastname: Oyama-Manabe
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shirato
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsutsui
mesh_terms: D000328:Adult; D015992:Body Mass Index; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D006801:Humans; D050356:Lipid Metabolism; D008055:Lipids / Q000032:analysis / Q000502:physiology; D008297:Male; D024821:Metabolic Syndrome / Q000378:metabolism / Q000503:physiopathology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism / Q000503:physiopathology*; D010101:Oxygen Consumption / Q000502:physiology*; D010725:Phosphocreatine / Q000378:metabolism / Q000502:physiology; D055105:Waist Circumference / Q000502:physiology
chemical_list: D008055:Lipids; D010725:Phosphocreatine