1
|
Toledo FGS, Dubé JJ, Goodpaster BH, Stefanovic-Racic M, Coen PM, DeLany JP. Mitochondrial Respiration is Associated with Lower Energy Expenditure and Lower Aerobic Capacity in African American Women. Obesity (Silver Spring) 2018; 26:903-909. [PMID: 29687648 PMCID: PMC5918421 DOI: 10.1002/oby.22163] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 02/14/2018] [Accepted: 02/15/2018] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Reasons for the higher obesity prevalence in African American women (AAW) compared with Caucasian women (CW) are unknown. Energy expenditure and maximal aerobic capacity (VO2 max) are lower in AAW. It was hypothesized that these differences are explained by skeletal muscle characteristics, particularly mitochondrial content and function. METHODS Multivariate regression analyses were used to examine the relationships between energy expenditure (resting and during a hyperinsulinemic-euglycemic clamp) and VO2 max versus body composition, physical activity, and skeletal muscle mitochondrial measurements in AAW and CW. RESULTS In AAW, VO2 max was lower (P < 0.0001). Body-composition-adjusted energy expenditure during the clamp was lower in AAW (P < 0.002). Physical activity was similar in both groups. After adjusting for mitochondrial respiration, racial differences in energy expenditure and VO2 max were no longer present. Another novel finding was that a thermogenic response to the clamp was observed in CW (+53 ± 22 kcal/d; P < 0.03) but not in AAW (-19 ± 24 kcal/d; P = 0.43). CONCLUSIONS AAW and CW show differences in adjusted energy expenditure and aerobic capacity that are largely accounted for by differences in skeletal muscle mitochondrial oxidative characteristics. Further research is needed to determine whether lower mitochondrial respiration and lower thermogenesis are risk factors for obesity in AAW.
Collapse
Affiliation(s)
- Frederico G S Toledo
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - John J Dubé
- Department of Biology, School of Arts, Science, and Business, Chatham University, Pittsburgh, Pennsylvania, USA
| | - Bret H Goodpaster
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida, USA
| | - Maja Stefanovic-Racic
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Paul M Coen
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida, USA
| | - James P DeLany
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| |
Collapse
|
2
|
O'Brien LC, Chen Q, Savas J, Lesnefsky EJ, Gorgey AS. Skeletal muscle mitochondrial mass is linked to lipid and metabolic profile in individuals with spinal cord injury. Eur J Appl Physiol 2017; 117:2137-2147. [PMID: 28864949 DOI: 10.1007/s00421-017-3687-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 07/25/2017] [Indexed: 02/07/2023]
Abstract
PURPOSE Changes in metabolism and body composition after spinal cord injury (SCI) predispose individuals to obesity, type II diabetes, and cardiovascular disease. A link between lean mass and skeletal muscle mitochondrial mass has been reported but it is unknown how skeletal muscle mitochondrial mass and activity impact metabolic health. This study examined the relationship between skeletal muscle mitochondrial mass, activity and metabolic profile in individuals with chronic SCI. METHODS Twenty-two men with motor complete SCI participated in the study. Citrate synthase (CS) and complex III (CIII) activity was measured in vastus lateralis biopsies. Metabolic profile was assessed by intravenous glucose tolerance test, basal metabolic rate (BMR), maximum oxygen uptake (VO2 peak) and blood lipid profile. RESULTS Skeletal muscle CS activity was negatively related to the cholesterol:high density lipoprotein cholesterol (HDL-C) ratio and triglycerides (r = -0.60, p = 0.009; r = -0.64, p = 0.004, respectively). CS activity was positively related to insulin sensitivity and BMR (r = 0.67, p = 0.006; r = 0.64, p = 0.005, respectively). Similar relationships were found for CIII and metabolic profile, but not CIII normalized to CS. Many of the relationships between CS and metabolism remained significant when age, level of injury, or time since injury were accounted for. They also remained significant when CS activity was normalized to total lean mass. CONCLUSIONS These results suggest that an increase in skeletal muscle mitochondrial mass is associated with improved metabolic health independent of age, level of injury, or time since injury in individuals with chronic SCI. This highlights the importance of maintaining and improving mitochondrial health in individuals with SCI.
Collapse
Affiliation(s)
- Laura C O'Brien
- Spinal Cord Injury Research, Spinal Cord Injury and Disorders Service, Hunter Holmes McGuire VA Medical Center, 1201 Broad Rock Blvd, Richmond, VA, 23249, USA
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
| | - Qun Chen
- Division of Cardiology, Department of Medicine, Pauley Heart Center, Virginia Commonwealth University, Richmond, VA, USA
| | - Jeannie Savas
- Surgery, Hunter Holmes McGuire VA Medical Center, Richmond, VA, USA
- Department of Surgery, Virginia Commonwealth University, Richmond, VA, USA
| | - Edward J Lesnefsky
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA, USA
- Division of Cardiology, Department of Medicine, Pauley Heart Center, Virginia Commonwealth University, Richmond, VA, USA
- Medical Services, Hunter Holmes McGuire VA Medical Center, Richmond, VA, USA
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, USA
| | - Ashraf S Gorgey
- Spinal Cord Injury Research, Spinal Cord Injury and Disorders Service, Hunter Holmes McGuire VA Medical Center, 1201 Broad Rock Blvd, Richmond, VA, 23249, USA.
- Department of Physical Medicine and Rehabilitation, Virginia Commonwealth University, Richmond, VA, USA.
| |
Collapse
|
3
|
Abstract
Evidence suggests that the growing prevalence of obesity in the workforce has resulted in an increase in the incidence and cost of musculoskeletal injuries. Obesity can modify job demands and affect worker capacity in terms of anthropometry and occupational biomechanics, which may place workers at greater risk of injury. This paper presents a review of studies quantifying the work-relevant impacts of obesity, specifically related to work task demands, capacities, and their potential imbalance. The increased body fat that accompanies obesity leads to larger anthropometric dimensions and inertial parameters, particularly in the trunk and thigh areas. Consequently, individuals who are obese adjust their work postures and motions as an accommodation. These changes may affect the biomechanical demands on the joints and increase the burden on the musculoskeletal system. Independent of job demands, obesity-related differences also occur with respect to strength, fatigue, and task performance. Directions for future research are provided, focusing on the need for workplace redesign to account for changing workforce demographics.
Collapse
Affiliation(s)
- Lora A Cavuoto
- Department of Industrial and Systems Engineering, University at Buffalo, 324 Bell Hall, Buffalo, NY, 14221, USA.
| | - Maury A Nussbaum
- Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, VA, USA
| |
Collapse
|
4
|
Cavuoto LA, Nussbaum MA. Obesity-related differences in muscular capacity during sustained isometric exertions. APPLIED ERGONOMICS 2013; 44:254-260. [PMID: 22858008 DOI: 10.1016/j.apergo.2012.07.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 06/07/2012] [Accepted: 07/16/2012] [Indexed: 06/01/2023]
Abstract
Over one-third of the world adult population is overweight or obese, and the prevalence continues to increase. Obesity is a risk factor for injury, and the growing prevalence may be associated with increases in the future incidence and cost of injuries. In this study, we examined obesity-related differences in muscular capacity during sustained isometric exertions involving hand grip, shoulder flexion, and trunk extension. Thirty-six young individuals who were obese or not obese (aged 18-29) completed these exertions at fixed levels of absolute loads involving low-moderate levels of effort. Individuals who were obese had an overall ∼20% higher absolute strength, but ∼20% lower relative strength. These differences were most evident in the hand grip and shoulder exertions. Parameters of fitted exponential relationships between endurance time and task demands (as a percentage of strength) were similar in both groups. Perceptual and performance responses were also consistent between groups. Accordingly, we conclude that obesity may not substantially influence muscular capacity for these tasks.
Collapse
Affiliation(s)
- Lora A Cavuoto
- Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, VA 24061, USA.
| | | |
Collapse
|
5
|
Lefort N, Glancy B, Bowen B, Willis WT, Bailowitz Z, De Filippis EA, Brophy C, Meyer C, Højlund K, Yi Z, Mandarino LJ. Increased reactive oxygen species production and lower abundance of complex I subunits and carnitine palmitoyltransferase 1B protein despite normal mitochondrial respiration in insulin-resistant human skeletal muscle. Diabetes 2010; 59:2444-52. [PMID: 20682693 PMCID: PMC3279558 DOI: 10.2337/db10-0174] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE The contribution of mitochondrial dysfunction to skeletal muscle insulin resistance remains elusive. Comparative proteomics are being applied to generate new hypotheses in human biology and were applied here to isolated mitochondria to identify novel changes in mitochondrial protein abundance present in insulin-resistant muscle. RESEARCH DESIGN AND METHODS Mitochondria were isolated from vastus lateralis muscle from lean and insulin-sensitive individuals and from obese and insulin-resistant individuals who were otherwise healthy. Respiration and reactive oxygen species (ROS) production rates were measured in vitro. Relative abundances of proteins detected by mass spectrometry were determined using a normalized spectral abundance factor method. RESULTS NADH- and FADH(2)-linked maximal respiration rates were similar between lean and obese individuals. Rates of pyruvate and palmitoyl-DL-carnitine (both including malate) ROS production were significantly higher in obesity. Mitochondria from obese individuals maintained higher (more negative) extramitochondrial ATP free energy at low metabolic flux, suggesting that stronger mitochondrial thermodynamic driving forces may underlie the higher ROS production. Tandem mass spectrometry identified protein abundance differences per mitochondrial mass in insulin resistance, including lower abundance of complex I subunits and enzymes involved in the oxidation of branched-chain amino acids (BCAA) and fatty acids (e.g., carnitine palmitoyltransferase 1B). CONCLUSIONS We provide data suggesting normal oxidative capacity of mitochondria in insulin-resistant skeletal muscle in parallel with high rates of ROS production. Furthermore, we show specific abundance differences in proteins involved in fat and BCAA oxidation that might contribute to the accumulation of lipid and BCAA frequently associated with the pathogenesis of insulin resistance.
Collapse
Affiliation(s)
- Natalie Lefort
- Center for Metabolic Biology, Arizona State University, Tempe, Arizona
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Brian Glancy
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Benjamin Bowen
- Center for Metabolic Biology, Arizona State University, Tempe, Arizona
| | - Wayne T. Willis
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Zachary Bailowitz
- Center for Metabolic Biology, Arizona State University, Tempe, Arizona
| | | | - Colleen Brophy
- Center for Metabolic Biology, Arizona State University, Tempe, Arizona
- Department of Kinesiology, Arizona State University, Tempe, Arizona
| | - Christian Meyer
- Center for Metabolic Biology, Arizona State University, Tempe, Arizona
| | - Kurt Højlund
- Harrington Department of Bioengineering, Arizona State University, Tempe, Arizona
| | - Zhengping Yi
- Center for Metabolic Biology, Arizona State University, Tempe, Arizona
- Diabetes Research Centre, Department of Endocrinology, Odense University Hospital, Odense, Denmark
| | - Lawrence J. Mandarino
- Center for Metabolic Biology, Arizona State University, Tempe, Arizona
- School of Life Sciences, Arizona State University, Tempe, Arizona
- Department of Medicine, Mayo Clinic in Arizona, Scottsdale, Arizona
- Corresponding author: Lawrence J. Mandarino,
| |
Collapse
|
6
|
Abstract
There is an accumulating amount of evidence indicating that lipid oxidation is depressed in the skeletal muscle of obese individuals. Decrements in fatty acid oxidation (FAO) have been reported with obesity in models ranging from whole body measurements to isolated skeletal muscle preparations as well as in myotubes raised in culture. This reduction appears to be associated with a depression in the activities of enzymes involved in various steps of lipid oxidation, which subsequently partitions lipid entering the cell toward storage. The defect in FAO in skeletal muscle may be critical in relation to health, as a reduction in the capacity for lipid oxidation could directly or indirectly contribute to the insulin resistance commonly evident with obesity. Although less characterized, a decrement in FAO has also been linked with weight gain, which suggests that this characteristic may be an integral aspect leading to the obese state. In terms of intervention, weight loss does not seem to correct the defect in FAO with obesity. This review will provide evidence supporting a reduction in muscle FAO with obesity.
Collapse
Affiliation(s)
- Joseph A Houmard
- Human Performance Laboratory, Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina 27858, USA.
| |
Collapse
|
7
|
Abstract
In spite of significant advances in the knowledge and understanding of the multi-factorial nature of obesity, many questions regarding the specific consequences of the disease remain unanswered. In particular, there is a relative dearth of information pertaining to the functional limitations imposed by overweight and obesity. The limited number of studies to date have mainly focused on the effect of obesity on the temporospatial characteristics of walking, plantar foot pressures, muscular strength and, to a lesser extent, postural balance. Collectively, these studies have implied that the functional limitations imposed by the additional loading of the locomotor system in obesity result in aberrant mechanics and the potential for musculoskeletal injury. Despite the greater prevalence of musculoskeletal disorders in the obese, there has been surprisingly little empirical investigation pertaining to the biomechanics of activities of daily living or into the mechanical and neuromuscular factors that may predispose the obese to injury. A better appreciation of the implications of increased levels of body adiposity on the movement capabilities of the obese would afford a greater opportunity to provide meaningful support in preventing, treating and managing the condition and its sequelae. Moreover, there is an urgent need to establish the physical consequences of continued repetitive loading of major structures of the body, particularly of the lower limbs in the obese, during the diverse range of activities of daily living.
Collapse
Affiliation(s)
- S C Wearing
- Institute of Health and Biomedical Innovation and School of Human Movement Studies, Queensland University of Technology, Queensland, Australia
| | | | | | | | | |
Collapse
|
8
|
Ukropcova B, McNeil M, Sereda O, de Jonge L, Xie H, Bray GA, Smith SR. Dynamic changes in fat oxidation in human primary myocytes mirror metabolic characteristics of the donor. J Clin Invest 2005; 115:1934-41. [PMID: 16007256 PMCID: PMC1159139 DOI: 10.1172/jci24332] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2004] [Accepted: 04/26/2005] [Indexed: 12/30/2022] Open
Abstract
Metabolic flexibility of skeletal muscle, that is, the preference for fat oxidation (FOx) during fasting and for carbohydrate oxidation in response to insulin, is decreased during insulin resistance. The aim of this study was to test the hypothesis that the capacity of myotubes to oxidize fat in vitro reflects the donor's metabolic characteristics. Insulin sensitivity (IS) and metabolic flexibility of 16 healthy, young male subjects was determined by euglycemic hyperinsulinemic clamp. Muscle samples were obtained from vastus lateralis, cultured, and differentiated into myotubes. In human myotubes in vitro, we measured suppressibility (glucose suppression of FOx) and adaptability (an increase in FOx in the presence of high palmitate concentration). We termed these dynamic changes in FOx metabolic switching. In vivo, metabolic flexibility was positively correlated with IS and maximal oxygen uptake and inversely correlated with percent body fat. In vitro suppressibility was inversely correlated with IS and metabolic flexibility and positively correlated with body fat and fasting FFA levels. Adaptability was negatively associated with percent body fat and fasting insulin and positively correlated with IS and metabolic flexibility. The interindividual variability in metabolic phenotypes was preserved in human myotubes separated from their neuroendocrine environment, which supports the hypothesis that metabolic switching is an intrinsic property of skeletal muscle.
Collapse
|