title: Improved Muscle Mitochondrial Capacity Following Gastric Bypass Surgery in Obese Subjects.
abstract: Weight loss resulting from low-calorie diets is often less than expected. We hypothesized that energy restriction would influence proton leakage and improve mitochondrial efficiency, leading to reduced energy expenditure, partly explaining the difficulties in weight loss maintenance.
  
  
  
  Eleven women with a median BMI of 38.5 kg/m(2) (q-range 37-40), and referred to gastric bypass surgery participated. Before surgery, and at 6 months of follow-up, muscle biopsies were collected from the vastus lateralis muscle. Mitochondria were isolated and analyzed for coupled (state 3) and uncoupled (state 4) respiration and mitochondrial capacity (P/O ratio).
  
  
  
  At follow-up, the participants had a median BMI of 29.6 kg/m(2) (28.3-32.0). State 3 increased from 20.6 (17.9-28.9) to 34.9 nmol O2/min/U citrate synthase (CS) (27.0-49.0), p = 0.01, while state 4 increased from 2.8 (1.8-4.2) to 4.2 nmol O2/min/U CS (3.1-6.1), although not statistically significant. The P/O ratio increased from 2.7 (2.5-2.8) to 3.2 (3.0-3.4), p = 0.02, indicating improved mitochondrial efficiency.
  
  
  
  Six months after gastric bypass surgery, the mitochondrial capacity for coupled, i.e., ATP-generating, respiration increased, and the P/O ratio improved. Uncoupled respiration was not enhanced to the same extent. This could partly explain the decreased basal metabolism and the reduced inclination for weight loss during energy restriction.
authors.affiliation: Department of Clinical Medicine, School of Health and Medical Sciences, Örebro University, Örebro, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Fernström
authors.affiliation: Department of Medicine, Clinical Epidemiology Unit, Karolinska Institutet Solna, T2, SE 171 76, Stockholm, Sweden.
authors.forename: Linda
authors.initials: L
authors.lastname: Bakkman
authors.affiliation: Bariatric Center, Sophiahemmet, Stockholm, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Loogna
authors.affiliation: Department of Anaesthesiology and Intensive Care, Karolinska Institutet Huddinge, Stockholm, Sweden.
authors.forename: Olav
authors.initials: O
authors.lastname: Rooyackers
authors.affiliation: Department of Medicine, Clinical Epidemiology Unit, Karolinska Institutet Solna, T2, SE 171 76, Stockholm, Sweden.|School of Health and Social Sciences, Halmstad University, Halmstad, Sweden.
authors.forename: Madeleine
authors.initials: M
authors.lastname: Svensson
authors.affiliation: Department of Anaesthesiology and Intensive Care, Karolinska Institutet Huddinge, Stockholm, Sweden.
authors.forename: Towe
authors.initials: T
authors.lastname: Jakobsson
authors.affiliation: Department of Clinical Medicine, School of Health and Medical Sciences, Örebro University, Örebro, Sweden.
authors.forename: Lena
authors.initials: L
authors.lastname: Brandt
authors.affiliation: Department of Medicine, Clinical Epidemiology Unit, Karolinska Institutet Solna, T2, SE 171 76, Stockholm, Sweden. ylva.trolle@ki.se.|Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital Huddinge, Stockholm, Sweden. ylva.trolle@ki.se.
authors.forename: Ylva Trolle
authors.initials: YT
authors.lastname: Lagerros
mesh_terms: D000328:Adult; D004038:Diet, Reducing; D005260:Female; D015390:Gastric Bypass; D006801:Humans; D008297:Male; D008875:Middle Aged; D008931:Mitochondria, Muscle / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009767:Obesity, Morbid / Q000601:surgery*; D011184:Postoperative Period; D015431:Weight Loss; D055815:Young Adult
keywords: Energy metabolism; Mitochondria; Muscle; Obesity; Thermogenesis; Weight loss