51
|
A multiscale modeling framework for studying the mechanobiology of sarcopenic obesity. Biomech Model Mechanobiol 2016; 16:275-295. [DOI: 10.1007/s10237-016-0816-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 08/08/2016] [Indexed: 01/08/2023]
|
52
|
Evaluation of the innate immune response of Angus heifers with genetic marker variation for intramuscular fat deposition following a lipopolysaccharide challenge. Livest Sci 2016. [DOI: 10.1016/j.livsci.2016.04.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
53
|
Hamrick MW, McGee-Lawrence ME, Frechette DM. Fatty Infiltration of Skeletal Muscle: Mechanisms and Comparisons with Bone Marrow Adiposity. Front Endocrinol (Lausanne) 2016; 7:69. [PMID: 27379021 PMCID: PMC4913107 DOI: 10.3389/fendo.2016.00069] [Citation(s) in RCA: 238] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 06/07/2016] [Indexed: 12/11/2022] Open
Abstract
Skeletal muscle and bone share common embryological origins from mesodermal cell populations and also display common growth trajectories early in life. Moreover, muscle and bone are both mechanoresponsive tissues, and the mass and strength of both tissues decline with age. The decline in muscle and bone strength that occurs with aging is accompanied in both cases by an accumulation of adipose tissue. In bone, adipocyte (AC) accumulation occurs in the marrow cavities of long bones and is known to increase with estrogen deficiency, mechanical unloading, and exposure to glucocorticoids. The factors leading to accumulation of intra- and intermuscular fat (myosteatosis) are less well understood, but recent evidence indicates that increases in intramuscular fat are associated with disuse, altered leptin signaling, sex steroid deficiency, and glucocorticoid treatment, factors that are also implicated in bone marrow adipogenesis. Importantly, accumulation of ACs in skeletal muscle and accumulation of intramyocellular lipid are linked to loss of muscle strength, reduced insulin sensitivity, and increased mortality among the elderly. Resistance exercise and whole body vibration can prevent fatty infiltration in skeletal muscle and also improve muscle strength. Therapeutic strategies to prevent myosteatosis may improve muscle function and reduce fall risk in the elderly, potentially impacting the incidence of bone fracture.
Collapse
Affiliation(s)
- Mark W. Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, GA, USA
- *Correspondence: Mark W. Hamrick,
| | | | | |
Collapse
|
54
|
Young HJ, Jenkins NT, Zhao Q, Mccully KK. Measurement of intramuscular fat by muscle echo intensity. Muscle Nerve 2015; 52:963-71. [PMID: 25787260 DOI: 10.1002/mus.24656] [Citation(s) in RCA: 276] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 03/06/2015] [Accepted: 03/11/2015] [Indexed: 12/14/2022]
Abstract
INTRODUCTION The aim of this study was to compare ultrasound echo intensity (EI) with high-resolution T1 -weighted MRI and to establish calibration equations to estimate percent intramuscular fat from EI. METHODS Thirty-one participants underwent both ultrasound and MRI testing of 4 muscles: rectus femoris (RF); biceps femoris (BF); tibialis anterior (TA); and medial gastrocnemius (MG). RESULTS Strong correlations were found between MRI percent fat and muscle EI after correcting for subcutaneous fat thickness (r = 0.91 in RF, r = 0.80 in BF, r = 0.80 in TA, r = 0.76 in MG). Three types of calibration equations were established. CONCLUSIONS Muscle ultrasound is a practical and reproducible method that can be used as an imaging technique for examination of percent intramuscular fat. Future ultrasound studies are needed to establish equations for other muscle groups to enhance its use in both research and clinical settings.
Collapse
Affiliation(s)
- Hui-Ju Young
- Department of Kinesiology, University of Georgia, Athens, Georgia, USA
| | - Nathan T Jenkins
- Department of Kinesiology, University of Georgia, Athens, Georgia, USA
| | - Qun Zhao
- Department of Physics and BioImaging Research Center, University of Georgia, Athens, Georgia, USA
| | - Kevin K Mccully
- Department of Kinesiology, University of Georgia, Athens, Georgia, USA
| |
Collapse
|
55
|
Contoured Foam Cushions Cannot Provide Long-term Protection Against Pressure-Ulcers for Individuals with a Spinal Cord Injury. Adv Skin Wound Care 2015; 28:303-16. [DOI: 10.1097/01.asw.0000465300.99194.27] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
56
|
Robinson SL, Hattersley J, Frost GS, Chambers ES, Wallis GA. Maximal fat oxidation during exercise is positively associated with 24-hour fat oxidation and insulin sensitivity in young, healthy men. J Appl Physiol (1985) 2015; 118:1415-22. [PMID: 25814634 DOI: 10.1152/japplphysiol.00058.2015] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 03/23/2015] [Indexed: 11/22/2022] Open
Abstract
Disturbances in fat oxidation have been associated with an increased risk of obesity and metabolic disorders such as insulin resistance. There is large intersubject variability in the capacity to oxidize fat when a person is physically active, although the significance of this for metabolic health is unclear. We investigated whether the maximal capacity to oxidize fat during exercise is related to 24-h fat oxidation and insulin sensitivity. Maximal fat oxidation (MFO; indirect calorimetry during incremental exercise) and insulin sensitivity (Quantitative Insulin Sensitivity Check Index) were measured in 53 young, healthy men (age 24 ± 7 yr, V̇o2max 52 ± 6 ml·kg(-1)·min(-1)). Fat oxidation over 24 h (24-h FO; indirect calorimetry) was assessed in 16 young, healthy men (age 26 ± 8 yr, V̇o2max 52 ± 6 ml·kg(-1)·min(-1)) during a 36-h stay in a whole-room respiration chamber. MFO (g/min) was positively correlated with 24-h FO (g/day) (R = 0.65, P = 0.003; R = 0.46, P = 0.041 when controlled for V̇o2max [l/min]), 24-h percent energy from FO (R = 0.58, P = 0.009), and insulin sensitivity (R = 0.33, P = 0.007). MFO (g/min) was negatively correlated with 24-h fat balance (g/day) (R = -0.51, P = 0.021) but not significantly correlated with 24-h respiratory quotient (R = -0.29, P = 0.142). Although additional investigations are needed, our data showing positive associations between MFO and 24-h FO, and between MFO and insulin sensitivity in healthy young men suggests that a high capacity to oxidize fat while one is physically active could be advantageous for the maintenance of metabolic health.
Collapse
Affiliation(s)
- Scott L Robinson
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - John Hattersley
- University Hospitals Coventry and Warwickshire, United Kingdom; University of Warwick, Coventry, United Kingdom; and
| | - Gary S Frost
- Nutrition and Dietetic Research Group, Imperial College, London, United Kingdom
| | - Edward S Chambers
- Nutrition and Dietetic Research Group, Imperial College, London, United Kingdom
| | - Gareth A Wallis
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom;
| |
Collapse
|
57
|
Ramos SV, Turnbull PC, MacPherson REK, LeBlanc PJ, Ward WE, Peters SJ. Changes in mitochondrial perilipin 3 and perilipin 5 protein content in rat skeletal muscle following endurance training and acute stimulated contraction. Exp Physiol 2015; 100:450-62. [PMID: 25663294 DOI: 10.1113/expphysiol.2014.084434] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 01/27/2015] [Indexed: 01/15/2023]
Abstract
NEW FINDINGS What is the central question of this study? The aim was to determine whether mitochondrial protein content of perilipin 3 (PLIN3) and perilipin 5 (PLIN5) is increased following endurance training and whether mitochondrial PLIN5 protein is increased to a greater extent in endurance-trained rats when compared with sedentary rats following acute contraction. What is the main finding and its importance? Mitochondrial PLIN3 but not PLIN5 protein was increased in endurance-trained compared with sedentary rats, suggesting a mitochondrial role for PLIN3 due to chronic exercise. Contrary to our hypothesis, acute mitochondrial PLIN5 protein was similar in both sedentary and endurance-trained rats. Endurance training results in an increased association between skeletal muscle lipid droplets and mitochondria. This association is likely to be important for the expected increase in intramuscular fatty acid oxidation that occurs with endurance training. The perilipin family of lipid droplet proteins, PLIN(2-5), are thought to play a role in skeletal muscle lipolysis. Recently, results from our laboratory demonstrated that skeletal muscle mitochondria contain PLIN3 and PLIN5 protein. Furthermore, 30 min of stimulated contraction induces an increased mitochondrial PLIN5 content. To determine whether mitochondrial content of PLIN3 and PLIN5 is altered with endurance training, Sprague-Dawley rats were randomized into sedentary or endurance-trained groups for 8 weeks of treadmill running followed by an acute (30 min) sciatic nerve stimulation to induce lipolysis. Mitochondrial PLIN3 protein was ∼1.5-fold higher in red gastrocnemius of endurance-trained rats compared with sedentary animals, with no change in mitochondrial PLIN5 protein. In addition, there was an increase in plantaris intramuscular lipid storage. Acute electrically stimulated contraction in red gastrocnemius from sedentary and endurance-trained rats resulted in a similar increase of mitochondrial PLIN5 between these two groups, with no net change in PLIN3 in either group. Plantaris intramuscular lipid content decreased to a similar extent in sedentary and endurance-trained rats. These results suggest that while total mitochondrial PLIN5 content is not altered by endurance training, PLIN5 does have an acute role in the mitochondrial fraction during muscle contraction. Conversely, mitochondrial PLIN3 does not change acutely with muscle contraction, but PLIN3 content was increased following endurance training, indicating a role in chronic adaptations of skeletal muscle.
Collapse
Affiliation(s)
- S V Ramos
- Center for Bone and Muscle Health, Brock University, St Catharines, Ontario, Canada; Department of Kinesiology, Brock University, St Catharines, Ontario, Canada
| | | | | | | | | | | |
Collapse
|
58
|
Maternal high-fat diet consumption impairs exercise performance in offspring. J Nutr Sci 2014; 3:e61. [PMID: 26101629 PMCID: PMC4473145 DOI: 10.1017/jns.2014.55] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/19/2014] [Accepted: 08/06/2014] [Indexed: 01/22/2023] Open
Abstract
The aim of the present study was to scrutinise the influence of maternal high-fat diet (mHFD) consumption during gestation and lactation on exercise performance and energy metabolism in male mouse offspring. Female C3H/HeJ mice were fed either a semi-synthetic high-fat diet (HFD; 40 % energy from fat) or a low-fat diet (LFD; 10 % energy from fat) throughout gestation and lactation. After weaning, male offspring of both groups received the LFD. At the age of 7·5 weeks half of the maternal LFD (n 20) and the mHFD (n 21) groups were given access to a running wheel for 28 d as a voluntary exercise training opportunity. We show that mHFD consumption led to a significantly reduced exercise performance (P < 0·05) and training efficiency (P < 0·05) in male offspring. There were no effects of maternal diet on offspring body weight. Lipid and glucose metabolism was disturbed in mHFD offspring, with altered regulation of cluster of differentiation 36 (CD36) (P < 0·001), fatty acid synthase (P < 0·05) and GLUT1 (P < 0·05) gene expression in skeletal muscle. In conclusion, maternal consumption of a HFD is linked to decreased exercise performance and training efficiency in the offspring. We speculate that this may be due to insufficient muscle energy supply during prolonged exercise training. Further, this compromised exercise performance might increase the risk of obesity development in adult life.
Collapse
Key Words
- CD36, cluster of differentiation 36
- Cpt1b, carnitine O-palmitoyltransferase 1b
- Esrrg, oestrogen-related receptor-γ
- FAS, fatty acid synthase
- HFD, high-fat diet
- High-fat diet
- LFD, low-fat diet
- Offspring
- REE, resting energy expenditure
- RQ, respiratory quotient
- RW, running wheel
- Serca2, sarcoplasmic/endoplasmic reticulum Ca ATPase 2
- Skeletal muscle
- Training
- eWAT, epididymal white adipose tissue
- mHFD, maternal high-fat diet
- mLFD, maternal low-fat diet
Collapse
|
59
|
Redzic M, Powell DK, Thomas DT. Vitamin D status is related to intramyocellular lipid in older adults. Endocrine 2014; 47:854-61. [PMID: 24676758 PMCID: PMC4386577 DOI: 10.1007/s12020-014-0238-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 03/10/2014] [Indexed: 12/17/2022]
Abstract
Vitamin D and intramyocellular lipid (IMCL) both affect muscle function, but the relationship between vitamin D status and IMCL has not been established. To assess the relationship between vitamin D [measured as 25-hydroxy-vitamin-D (25(OH)D)] and IMCL, 20 community-dwelling adults between the ages of 65 and 85 were recruited. Serum 25(OH)D, and gastrocnemius IMCL and extramyocellular lipid (EMCL) were measured with magnetic resonance spectroscopy and fat ratio segmentation. A lifestyle questionnaire assessed physical activity. Muscle strength (1-repetition maximum) and physical function tests (timed up and go, timed sit to stand, four square step test, and gait speed) were also performed. Mean 25(OH)D was 37.9 ± 13.1 ng/mL with a range of 19-68 ng/mL. Soleus and gastrocnemius IMCL to water ratio was 1.04 ± 0.43 and 0.53 ± 0.22, respectively, but only gastrocnemius IMCL was correlated with 25(OH)D (R (2) = 0.39; p = 0.02). This relationship was independent of body mass index (p > 0.14), physical activity level (p > 0.08), and sex (p > 0.13). 25(OH)D did not correlate with EMCL (R (2) = 0.007; p = 0.78). The four square step test was the only performance or strength test correlated with 25(OH)D (R (2) = 0.26; p = 0.023). Muscle strength and physical function measures were not correlated with IMCL or EMCL. These data suggest that vitamin D status may influence gastrocnemius IMCL content independent of body mass and physical activity. Future studies should consider exploring whether vitamin D has an independent role in affecting muscle lipid metabolism and function.
Collapse
Affiliation(s)
- Maja Redzic
- Division of Clinical Nutrition, University of Kentucky, 900 South Limestone, 209H CTW Building, Lexington, KY 40536, USA
| | - David K. Powell
- Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky, Lexington, KY, USA
| | - D. Travis Thomas
- Division of Clinical Nutrition, University of Kentucky, 900 South Limestone, 209H CTW Building, Lexington, KY 40536, USA
| |
Collapse
|
60
|
Stavropoulos-Kalinoglou A, Deli C, Kitas GD, Jamurtas AZ. Muscle wasting in rheumatoid arthritis: The role of oxidative stress. World J Rheumatol 2014; 4:44-53. [DOI: 10.5499/wjr.v4.i3.44] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 09/01/2014] [Accepted: 09/24/2014] [Indexed: 02/06/2023] Open
Abstract
Rheumatoid arthritis (RA), the commonest inflammatory arthritis, is a debilitating disease leading to functional and social disability. In addition to the joints, RA affects several other tissues of the body including the muscle. RA patients have significantly less muscle mass compared to the general population. Several theories have been proposed to explain this. High grade inflammation, a central component in the pathophysiology of the disease, has long been proposed as the key driver of muscle wasting. More recent findings however, indicate that inflammation on its own cannot fully explain the high prevalence of muscle wasting in RA. Thus, the contribution of other potential confounders, such as nutrition and physical activity, has also been studied. Results indicate that they play a significant role in muscle wasting in RA, but again neither of these factors seems to be able to fully explain the condition. Oxidative stress is one of the major mechanisms thought to contribute to the development and progression of RA but its potential contribution to muscle wasting in these patients has received limited attention. Oxidative stress has been shown to promote muscle wasting in healthy populations and people with several chronic conditions. Moreover, all of the aforementioned potential contributors to muscle wasting in RA (i.e., inflammation, nutrition, and physical activity) may promote pro- or anti-oxidative mechanisms. This review aims to highlight the importance of oxidative stress as a driving mechanism for muscle wasting in RA and discusses potential interventions that may promote muscle regeneration via reduction in oxidative stress.
Collapse
|
61
|
Abstract
The importance of skeletal muscle for metabolic health and obesity prevention is gradually gaining recognition. As a result, interventions are being developed to increase or maintain muscle mass and metabolic function in adult and elderly populations. These interventions include exercise, hormonal and nutritional therapies. Nonetheless, growing evidence suggests that maternal malnutrition and obesity during pregnancy and lactation impede skeletal muscle development and growth in the offspring, with long-term functional consequences lasting into adult life. Here we review the role of skeletal muscle in health and obesity, providing an insight into how this tissue develops and discuss evidence that maternal obesity affects its development, growth and function into adult life. Such evidence warrants the need to develop early life interventions to optimise skeletal muscle development and growth in the offspring and thereby maximise metabolic health into adult life.
Collapse
|
62
|
Aon MA, Bhatt N, Cortassa SC. Mitochondrial and cellular mechanisms for managing lipid excess. Front Physiol 2014; 5:282. [PMID: 25132820 PMCID: PMC4116787 DOI: 10.3389/fphys.2014.00282] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 07/10/2014] [Indexed: 12/16/2022] Open
Abstract
Current scientific debates center on the impact of lipids and mitochondrial function on diverse aspects of human health, nutrition and disease, among them the association of lipotoxicity with the onset of insulin resistance in skeletal muscle, and with heart dysfunction in obesity and diabetes. Mitochondria play a fundamental role in aging and in prevalent acute or chronic diseases. Lipids are main mitochondrial fuels however these molecules can also behave as uncouplers and inhibitors of oxidative phosphorylation. Knowledge about the functional composition of these contradictory effects and their impact on mitochondrial-cellular energetics/redox status is incomplete. Cells store fatty acids (FAs) as triacylglycerol and package them into cytoplasmic lipid droplets (LDs). New emerging data shows the LD as a highly dynamic storage pool of FAs that can be used for energy reserve. Lipid excess packaging into LDs can be seen as an adaptive response to fulfilling energy supply without hindering mitochondrial or cellular redox status and keeping low concentration of lipotoxic intermediates. Herein we review the mechanisms of action and utilization of lipids by mitochondria reported in liver, heart and skeletal muscle under relevant physiological situations, e.g., exercise. We report on perilipins, a family of proteins that associate with LDs in response to loading of cells with lipids. Evidence showing that in addition to physical contact, mitochondria and LDs exhibit metabolic interactions is presented and discussed. A hypothetical model of channeled lipid utilization by mitochondria is proposed. Direct delivery and channeled processing of lipids in mitochondria could represent a reliable and efficient way to maintain reactive oxygen species (ROS) within levels compatible with signaling while ensuring robust and reliable energy supply.
Collapse
Affiliation(s)
- Miguel A Aon
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Niraj Bhatt
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Sonia C Cortassa
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, MD, USA
| |
Collapse
|
63
|
Shepherd SO, Cocks M, Tipton KD, Witard OC, Ranasinghe AM, Barker TA, Wagenmakers AJM, Shaw CS. Resistance training increases skeletal muscle oxidative capacity and net intramuscular triglyceride breakdown in type I and II fibres of sedentary males. Exp Physiol 2014; 99:894-908. [DOI: 10.1113/expphysiol.2014.078014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- S. O. Shepherd
- Research Institute for Sport & Exercise Sciences; Liverpool John Moores University; Liverpool UK
| | - M. Cocks
- Research Institute for Sport & Exercise Sciences; Liverpool John Moores University; Liverpool UK
| | - K. D. Tipton
- Health and Exercise Sciences Research Group; University of Stirling; Stirling UK
| | - O. C. Witard
- Health and Exercise Sciences Research Group; University of Stirling; Stirling UK
| | - A. M. Ranasinghe
- School of Clinical and Experimental Medicine; Cardiovascular and Respiratory Sciences; University of Birmingham; Birmingham UK
| | - T. A. Barker
- School of Clinical and Experimental Medicine; Cardiovascular and Respiratory Sciences; University of Birmingham; Birmingham UK
| | - A. J. M. Wagenmakers
- Research Institute for Sport & Exercise Sciences; Liverpool John Moores University; Liverpool UK
| | - C. S. Shaw
- Institute of Sport, Exercise & Active Living; Victoria University; Melbourne Victoria Australia
| |
Collapse
|
64
|
Malik ZA, Cobley JN, Morton JP, Close GL, Edwards BJ, Koch LG, Britton SL, Burniston JG. Label-Free LC-MS Profiling of Skeletal Muscle Reveals Heart-Type Fatty Acid Binding Protein as a Candidate Biomarker of Aerobic Capacity. Proteomes 2013; 1:290-308. [PMID: 24772389 PMCID: PMC3997170 DOI: 10.3390/proteomes1030290] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Two-dimensional gel electrophoresis provides robust comparative analysis of skeletal muscle, but this technique is laborious and limited by its inability to resolve all proteins. In contrast, orthogonal separation by SDS-PAGE and reverse-phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) affords deep mining of the muscle proteome, but differential analysis between samples is challenging due to the greater level of fractionation and the complexities of quantifying proteins based on the abundances of their tryptic peptides. Here we report simple, semi-automated and time efficient (i.e., 3 h per sample) proteome profiling of skeletal muscle by 1-dimensional RPLC electrospray ionisation tandem MS. Solei were analysed from rats (n = 5, in each group) bred as either high- or low-capacity runners (HCR and LCR, respectively) that exhibited a 6.4-fold difference (1,625 ± 112 m vs. 252 ± 43 m, p < 0.0001) in running capacity during a standardized treadmill test. Soluble muscle proteins were extracted, digested with trypsin and individual biological replicates (50 ng of tryptic peptides) subjected to LC-MS profiling. Proteins were identified by triplicate LC-MS/MS analysis of a pooled sample of each biological replicate. Differential expression profiling was performed on relative abundances (RA) of parent ions, which spanned three orders of magnitude. In total, 207 proteins were analysed, which encompassed almost all enzymes of the major metabolic pathways in skeletal muscle. The most abundant protein detected was type I myosin heavy chain (RA = 5,843 ± 897) and the least abundant protein detected was heat shock 70 kDa protein (RA = 2 ± 0.5). Sixteen proteins were significantly (p < 0.05) more abundant in HCR muscle and hierarchal clustering of the profiling data highlighted two protein subgroups, which encompassed proteins associated with either the respiratory chain or fatty acid oxidation. Heart-type fatty acid binding protein (FABPH) was 1.54-fold (p = 0.0064) more abundant in HCR than LCR soleus. This discovery was verified using selective reaction monitoring (SRM) of the y5 ion (551.21 m/z) of the doubly-charged peptide SLGVGFATR (454.19 m/z) of residues 23–31 of FABPH. SRM was conducted on technical replicates of each biological sample and exhibited a coefficient of variation of 20%. The abundance of FABPH measured by SRM was 2.84-fold greater (p = 0.0095) in HCR muscle. In addition, SRM of FABPH was performed in vastus lateralis samples of young and elderly humans with different habitual activity levels (collected during a previous study) finding FABPH abundance was 2.23-fold greater (p = 0.0396) in endurance-trained individuals regardless of differences in age. In summary, our findings in HCR/LCR rats provide protein-level confirmation for earlier transcriptome profiling work and show LC-MS is a viable means of profiling the abundance of almost all major metabolic enzymes of skeletal muscle in a highly parallel manner. Moreover, our approach is relatively more time efficient than techniques relying on orthogonal separations, and we demonstrate LC-MS profiling of the HCR/LCR selection model was able to highlight biomarkers that also exhibit differences in trained and untrained human muscle.
Collapse
Affiliation(s)
- Zulezwan A. Malik
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK; E-Mails: (Z.A.M.); (J.N.C.); (J.P.M.); (G.L.C.); (B.J.E.)
| | - James N. Cobley
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK; E-Mails: (Z.A.M.); (J.N.C.); (J.P.M.); (G.L.C.); (B.J.E.)
| | - James P. Morton
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK; E-Mails: (Z.A.M.); (J.N.C.); (J.P.M.); (G.L.C.); (B.J.E.)
| | - Graeme L. Close
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK; E-Mails: (Z.A.M.); (J.N.C.); (J.P.M.); (G.L.C.); (B.J.E.)
| | - Ben J. Edwards
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK; E-Mails: (Z.A.M.); (J.N.C.); (J.P.M.); (G.L.C.); (B.J.E.)
| | - Lauren G. Koch
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI 48109-2200, USA; E-Mails: (L.G.K.); (S.L.B.)
| | - Steven L. Britton
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI 48109-2200, USA; E-Mails: (L.G.K.); (S.L.B.)
| | - Jatin G. Burniston
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK; E-Mails: (Z.A.M.); (J.N.C.); (J.P.M.); (G.L.C.); (B.J.E.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +44-904-6265; Fax: +44-904-6283
| |
Collapse
|
65
|
Abstract
The endocrine system plays a major role in human survival. Endocrine glands secrete chemical messengers or hormones that affect every tissue of the body, including the periodontium, during the life of the individual. As the endocrine system influences a broad assortment of biological activities necessary for life, a general understanding of the principal components and functions of this system is essential. A fundamental assessment of hormone structure, mechanism of action and hormone transport, as well as influence on homeostasis is reviewed. A concise evaluation of the functions of the central endocrine glands, the functions of the major peripheral endocrine glands (other than gonadal tissues) and the known relationships of these hormones to the periodontium is examined.
Collapse
|
66
|
|
67
|
Kanosky KM, Ippagunta S, Barnes KM. Mice do not accumulate muscle lipid in response to dietary conjugated linoleic acid. J Anim Sci 2013; 91:4705-12. [PMID: 23942710 DOI: 10.2527/jas.2013-6407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Dietary CLA decreases body fat in several species and in pigs this is accompanied by increased muscle lipid. Our objective was to determine if mice could be used as a model for CLA-induced increased marbling in pigs. We used our model of enhanced CLA response, where mice fed coconut oil (CO) lose more body fat than mice fed soy oil (SO). Mice (21 d old; Imprinting Control Region [ICR]) were fed SO or CO diets for 6 wk followed by 12 d of 0 or 0.5% mixed isomer CLA. Ether extraction determined that thigh muscle lipid content was reduced by both CLA and CO (P = 0.007 and P = 0.006, respectively). Conjugated linoleic acid also caused a reduction (P = 0.016) in carnitine palmitoyltransferase (CPT) enzyme activity, so less fatty acid oxidation appeared to be occurring. Lumbar muscle, which is more similar to the longissimus dorsi tested in pigs, did not differ in lipid content between mice (56 d old; ICR) fed SO or SO+CLA for 14 d. Therefore, CLA-fed mice do not appear to be accumulating excess lipid in their muscle. However, CLA addition to CO diets increased (P = 0.007) the mRNA expression of PPAR-γ in the thigh muscle to the level of SO-fed mice, indicating that intramuscular adipocyte differentiation may be increasing. On the other hand, liver lipid was increased (P < 0.0001) by CO and tended to be increased (P = 0.099) by CLA. Liver CPT activity was decreased (P = 0.018) in SO+CLA-fed mice but not CO+CLA. It appears that mice may accumulate lipid in their livers preferentially over muscle when fed CLA and therefore are not a good model for CLA-induced muscle lipid accumulation.
Collapse
Affiliation(s)
- K M Kanosky
- Division of Animal and Nutritional Sciences, West Virginia University, PO Box 6108, Morgantown 26506
| | | | | |
Collapse
|
68
|
Lim S, Meigs JB. Ectopic fat and cardiometabolic and vascular risk. Int J Cardiol 2013; 169:166-76. [PMID: 24063931 DOI: 10.1016/j.ijcard.2013.08.077] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 06/16/2013] [Accepted: 08/28/2013] [Indexed: 12/16/2022]
Abstract
Given that the variation in how regional adipose tissue handles and stores excess dietary energy has substantial cardiometabolic implications, ectopic fat distribution might be an important predictor of cardiometabolic and vascular risk, in addition to overall obesity itself. Conceptually, ectopic fat depots may be divided into systemically acting fat depots and locally acting fat depots. Systemically acting fat depots include visceral fat, fat in the liver, muscle, or neck, and subcutaneous fat. Accumulation in the abdominal visceral area, compared with overall obesity, has an equally or more important role in the development of cardiometabolic risk. Fat depots in liver/muscle tissue cause adverse cardiometabolic effects by affecting energy metabolism. Fat depots in lower-body subcutaneous areas may be protective regarding cardiometabolic risk, by trapping remnant energy. Fat accumulation in the neck is a unique type of fat depot that may increase cardiovascular risk by increasing insulin resistance. Locally acting fat depots include pericardial fat, perivascular fat, and renal sinus fat. These fat depots have effects primarily on adjacent anatomic organs, directly via lipotoxicity and indirectly via cytokine secretion. Pericardial fat is associated with coronary atherosclerosis. Perivascular fat may play an independent role in adverse vascular biology, including arterial stiffness. Renal sinus fat is a unique fat depot that may confer additional cardiometabolic risk. Thus, ectopic fat depots may contribute to the understanding of the link between body composition and cardiometabolic risk. In this review, we focus on the role and clinical implications of ectopic fat depots in cardiometabolic and vascular risk.
Collapse
Affiliation(s)
- Soo Lim
- General Medicine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seoul, South Korea.
| | | |
Collapse
|
69
|
Conte M, Vasuri F, Trisolino G, Bellavista E, Santoro A, Degiovanni A, Martucci E, D'Errico-Grigioni A, Caporossi D, Capri M, Maier AB, Seynnes O, Barberi L, Musarò A, Narici MV, Franceschi C, Salvioli S. Increased Plin2 expression in human skeletal muscle is associated with sarcopenia and muscle weakness. PLoS One 2013; 8:e73709. [PMID: 23977392 PMCID: PMC3744478 DOI: 10.1371/journal.pone.0073709] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 07/22/2013] [Indexed: 11/28/2022] Open
Abstract
Human aging is associated with a progressive loss of muscle mass and strength and a concomitant fat accumulation in form of inter-muscular adipose tissue, causing skeletal muscle function decline and immobilization. Fat accumulation can also occur as intra-muscular triglycerides (IMTG) deposition in lipid droplets, which are associated with perilipin proteins, such as Perilipin2 (Plin2). It is not known whether Plin2 expression changes with age and if this has consequences on muscle mass and strength. We studied the expression of Plin2 in the vastus lateralis (VL) muscle of both healthy subjects and patients affected by lower limb mobility limitation of different age. We found that Plin2 expression increases with age, this phenomenon being particularly evident in patients. Moreover, Plin2 expression is inversely correlated with quadriceps strength and VL thickness. To investigate the molecular mechanisms underpinning this phenomenon, we focused on IGF-1/p53 network/signalling pathway, involved in muscle physiology. We found that Plin2 expression strongly correlates with increased p53 activation and reduced IGF-1 expression. To confirm these observations made on humans, we studied mice overexpressing muscle-specific IGF-1, which are protected from sarcopenia. These mice resulted almost negative for the expression of Plin2 and p53 at two years of age. We conclude that fat deposition within skeletal muscle in form of Plin2-coated lipid droplets increases with age and is associated with decreased muscle strength and thickness, likely through an IGF-1- and p53-dependent mechanism. The data also suggest that excessive intramuscular fat accumulation could be the initial trigger for p53 activation and consequent loss of muscle mass and strength.
Collapse
Affiliation(s)
- Maria Conte
- Department of Experimental, Diagnostic and Specialty Medicine and Interdepartmental Centre L Galvani, CIG, University of Bologna, Bologna, Italy.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
70
|
Koves TR, Sparks LM, Kovalik JP, Mosedale M, Arumugam R, DeBalsi KL, Everingham K, Thorne L, Phielix E, Meex RC, Kien CL, Hesselink MKC, Schrauwen P, Muoio DM. PPARγ coactivator-1α contributes to exercise-induced regulation of intramuscular lipid droplet programming in mice and humans. J Lipid Res 2013; 54:522-34. [PMID: 23175776 PMCID: PMC3588877 DOI: 10.1194/jlr.p028910] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 10/27/2012] [Indexed: 11/20/2022] Open
Abstract
Intramuscular accumulation of triacylglycerol, in the form of lipid droplets (LD), has gained widespread attention as a hallmark of metabolic disease and insulin resistance. Paradoxically, LDs also amass in muscles of highly trained endurance athletes who are exquisitely insulin sensitive. Understanding the molecular mechanisms that mediate the expansion and appropriate metabolic control of LDs in the context of habitual physical activity could lead to new therapeutic opportunities. Herein, we show that acute exercise elicits robust upregulation of a broad program of genes involved in regulating LD assembly, morphology, localization, and mobilization. Prominent among these was perilipin-5, a scaffolding protein that affects the spatial and metabolic interactions between LD and their surrounding mitochondrial reticulum. Studies in transgenic mice and primary human skeletal myocytes established a key role for the exercise-responsive transcriptional coactivator PGC-1α in coordinating intramuscular LD programming with mitochondrial remodeling. Moreover, translational studies comparing physically active versus inactive humans identified a remarkably strong association between expression of intramuscular LD genes and enhanced insulin action in exercise-trained subjects. These results reveal an intimate molecular connection between intramuscular LD biology and mitochondrial metabolism that could prove relevant to the etiology and treatment of insulin resistance and other disorders of lipid imbalance.
Collapse
Affiliation(s)
- Timothy R. Koves
- Sarah W. Stedman Nutrition & Metabolism Center, Duke University, Durham, NC
- Department of Medicine, Duke University, Durham, NC
| | - Lauren M. Sparks
- Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht, The Netherlands
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, FL
| | - J. P. Kovalik
- Sarah W. Stedman Nutrition & Metabolism Center, Duke University, Durham, NC
| | - Merrie Mosedale
- Sarah W. Stedman Nutrition & Metabolism Center, Duke University, Durham, NC
| | - Ramamani Arumugam
- Sarah W. Stedman Nutrition & Metabolism Center, Duke University, Durham, NC
| | - Karen L. DeBalsi
- Sarah W. Stedman Nutrition & Metabolism Center, Duke University, Durham, NC
| | - Karen Everingham
- Department of Pediatrics and Medicine, University of Vermont, Colchester, VT
| | - Leigh Thorne
- Department of Pathology & Laboratory Medicine, University of North Carolina, Chapel-Hill, NC
| | - Esther Phielix
- Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Ruth C. Meex
- Department of Human Movement Sciences, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - C. Lawrence Kien
- Department of Pediatrics and Medicine, University of Vermont, Colchester, VT
| | - Matthijs K. C. Hesselink
- Department of Human Movement Sciences, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Patrick Schrauwen
- Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Deborah M. Muoio
- Sarah W. Stedman Nutrition & Metabolism Center, Duke University, Durham, NC
- Department of Medicine, Duke University, Durham, NC
- Department of Pharmacology & Cancer Biology, Duke University, Durham, NC
| |
Collapse
|
71
|
Chowdhury KK, Legare DJ, Lautt WW. Lifestyle impact on meal-induced insulin sensitization in health and prediabetes: A focus on diet, antioxidants, and exercise interventions. Can J Physiol Pharmacol 2013; 91:91-100. [DOI: 10.1139/cjpp-2012-0228] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The augmented whole-body glucose uptake response to insulin during the postprandial state is described as meal-induced insulin sensitization (MIS). MIS occurs when the presence of food in the upper gastrointestinal tract activates 2 feeding signals (activation of hepatic parasympathetic nerves and elevation of hepatic glutathione level), and causes insulin to release hepatic insulin sensitizing substance (HISS), which stimulates glucose uptake in skeletal muscle, heart, and kidneys. HISS action results in nutrient storage, primarily as glycogen. Impairment of HISS release results in the absence of meal-induced insulin sensitization (AMIS), which causes postprandial hyperglycemia and hyperinsulinemia, and chronically leads to the progression to a cluster of metabolic, vascular, and cardiac dysfunctions, which we refer to as components of the AMIS syndrome. Manipulation of the MIS process in health and in disease, by pharmacological and nonpharmacological interventions, is outlined in this review. High fat or sugar supplemented diet reduces MIS; exercise elevates MIS; and antioxidants protect MIS against reductions associated with diet and age.
Collapse
Affiliation(s)
- Kawshik K. Chowdhury
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Manitoba, A210 – 753 McDermot Avenue, Winnipeg, MB R3E 0T6, Canada
| | - Dallas J. Legare
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Manitoba, A210 – 753 McDermot Avenue, Winnipeg, MB R3E 0T6, Canada
| | - W. Wayne Lautt
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Manitoba, A210 – 753 McDermot Avenue, Winnipeg, MB R3E 0T6, Canada
| |
Collapse
|
72
|
Responses to administration of growth hormone releasing hormone and glucose in steers receiving stair-step and extended restriction on feeding. Livest Sci 2012. [DOI: 10.1016/j.livsci.2012.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
73
|
Farr JN, Van Loan MD, Lohman TG, Going SB. Lower physical activity is associated with skeletal muscle fat content in girls. Med Sci Sports Exerc 2012; 44:1375-81. [PMID: 22217562 DOI: 10.1249/mss.0b013e31824749b2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UNLABELLED Fat contained within skeletal muscle is strongly associated with obesity, type 2 diabetes mellitus, and metabolic syndrome. Physical inactivity may be a risk factor for greater fat infiltration within skeletal muscle during growth. PURPOSE We sought to examine the relationship between physical activity and skeletal muscle fat content of the calf and thigh in girls. METHODS Data from 464 girls, age 8-13 yr, were used to examine the relationship between physical activity and skeletal muscle fat content of the calf and thigh. Calf and thigh muscle density (mg·cm(-3)), an index of skeletal muscle fat content, was assessed at the 66% tibia and 20% femur sites relative to the respective distal growth plates of the nondominant limb using peripheral quantitative computed tomography. Physical activity level was classified by past-year physical activity questionnaire score. RESULTS Muscle densities of the calf and thigh were inversely correlated with percent total body fat (r = -0.37 and -0.48, P values < 0.001) and total body fat mass (r = -0.33 and -0.40, P values < 0.001). Multiple linear regression with physical activity, ethnicity, maturity offset, and muscle cross-sectional area as independent variables showed that physical activity was independently associated with muscle densities of the calf (β = 0.14, P = 0.002) and thigh (β = 0.15, P < 0.001). Thus, lower physical activity was associated with higher skeletal muscle fat content. CONCLUSIONS Our results suggest that a lower level of physical activity may lead to excess skeletal muscle fat content of the calf and thigh in girls.
Collapse
Affiliation(s)
- Joshua Nicholas Farr
- Department of Physiological Sciences, The University of Arizona, Tucson, AZ 85721-0093, USA.
| | | | | | | |
Collapse
|
74
|
Shepherd SO, Cocks M, Tipton KD, Ranasinghe AM, Barker TA, Burniston JG, Wagenmakers AJM, Shaw CS. Sprint interval and traditional endurance training increase net intramuscular triglyceride breakdown and expression of perilipin 2 and 5. J Physiol 2012; 591:657-75. [PMID: 23129790 DOI: 10.1113/jphysiol.2012.240952] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Intramuscular triglyceride (IMTG) utilization is enhanced by endurance training (ET) and is linked to improved insulin sensitivity. This study first investigated the hypothesis that ET-induced increases in net IMTG breakdown and insulin sensitivity are related to increased expression of perilipin 2 (PLIN2) and perilipin 5 (PLIN5). Second, we hypothesized that sprint interval training (SIT) also promotes increases in IMTG utilization and insulin sensitivity. Sixteen sedentary males performed 6 weeks of either SIT (4-6, 30 s Wingate tests per session, 3 days week(-1)) or ET (40-60 min moderate-intensity cycling, 5 days week(-1)). Training increased resting IMTG content (SIT 1.7-fold, ET 2.4-fold; P < 0.05), concomitant with parallel increases in PLIN2 (SIT 2.3-fold, ET 2.8-fold; P < 0.01) and PLIN5 expression (SIT 2.2-fold, ET 3.1-fold; P < 0.01). Pre-training, 60 min cycling at ∼65% pre-training decreased IMTG content in type I fibres (SIT 17 ± 10%, ET 15 ± 12%; P < 0.05). Following training, a significantly greater breakdown of IMTG in type I fibres occurred during exercise (SIT 27 ± 13%, ET 43 ± 6%; P < 0.05), with preferential breakdown of PLIN2- and particularly PLIN5-associated lipid droplets. Training increased the Matsuda insulin sensitivity index (SIT 56 ± 15%, ET 29 ± 12%; main effect P < 0.05). No training × group interactions were observed for any variables. In conclusion, SIT and ET both increase net IMTG breakdown during exercise and increase in PLIN2 and PLIN5 protein expression. The data are consistent with the hypothesis that increases in PLIN2 and PLIN5 are related to the mechanisms that promote increased IMTG utilization during exercise and improve insulin sensitivity following 6 weeks of SIT and ET.
Collapse
Affiliation(s)
- S O Shepherd
- School of Sport & Exercise Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | | | | | | | | | | | | | | |
Collapse
|
75
|
Holt LJ, Turner N, Mokbel N, Trefely S, Kanzleiter T, Kaplan W, Ormandy CJ, Daly RJ, Cooney GJ. Grb10 regulates the development of fiber number in skeletal muscle. FASEB J 2012; 26:3658-69. [DOI: 10.1096/fj.11-199349] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Lowenna J. Holt
- Diabetes and Obesity Research ProgramGarvan Institute of Medical ResearchSydneyNew South WalesAustralia
| | - Nigel Turner
- Diabetes and Obesity Research ProgramGarvan Institute of Medical ResearchSydneyNew South WalesAustralia
- St. Vincent's Hospital Clinical SchoolUniversity of New South WalesSydneyNew South WalesAustralia
| | - Nancy Mokbel
- Diabetes and Obesity Research ProgramGarvan Institute of Medical ResearchSydneyNew South WalesAustralia
| | - Sophie Trefely
- Diabetes and Obesity Research ProgramGarvan Institute of Medical ResearchSydneyNew South WalesAustralia
| | - Timo Kanzleiter
- Diabetes and Obesity Research ProgramGarvan Institute of Medical ResearchSydneyNew South WalesAustralia
| | - Warren Kaplan
- Peter Wills Bioinformatics CentreGarvan Institute of Medical ResearchSydneyNew South WalesAustralia
| | - Christopher J. Ormandy
- Cancer Research ProgramGarvan Institute of Medical ResearchSydneyNew South WalesAustralia
- St. Vincent's Hospital Clinical SchoolUniversity of New South WalesSydneyNew South WalesAustralia
| | - Roger J. Daly
- Cancer Research ProgramGarvan Institute of Medical ResearchSydneyNew South WalesAustralia
- St. Vincent's Hospital Clinical SchoolUniversity of New South WalesSydneyNew South WalesAustralia
| | - Gregory J. Cooney
- Diabetes and Obesity Research ProgramGarvan Institute of Medical ResearchSydneyNew South WalesAustralia
- St. Vincent's Hospital Clinical SchoolUniversity of New South WalesSydneyNew South WalesAustralia
| |
Collapse
|
76
|
Haldar SM, Jeyaraj D, Anand P, Zhu H, Lu Y, Prosdocimo DA, Eapen B, Kawanami D, Okutsu M, Brotto L, Fujioka H, Kerner J, Rosca MG, McGuinness OP, Snow RJ, Russell AP, Gerber AN, Bai X, Yan Z, Nosek TM, Brotto M, Hoppel CL, Jain MK. Kruppel-like factor 15 regulates skeletal muscle lipid flux and exercise adaptation. Proc Natl Acad Sci U S A 2012; 109:6739-44. [PMID: 22493257 PMCID: PMC3340075 DOI: 10.1073/pnas.1121060109] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability of skeletal muscle to enhance lipid utilization during exercise is a form of metabolic plasticity essential for survival. Conversely, metabolic inflexibility in muscle can cause organ dysfunction and disease. Although the transcription factor Kruppel-like factor 15 (KLF15) is an important regulator of glucose and amino acid metabolism, its endogenous role in lipid homeostasis and muscle physiology is unknown. Here we demonstrate that KLF15 is essential for skeletal muscle lipid utilization and physiologic performance. KLF15 directly regulates a broad transcriptional program spanning all major segments of the lipid-flux pathway in muscle. Consequently, Klf15-deficient mice have abnormal lipid and energy flux, excessive reliance on carbohydrate fuels, exaggerated muscle fatigue, and impaired endurance exercise capacity. Elucidation of this heretofore unrecognized role for KLF15 now implicates this factor as a central component of the transcriptional circuitry that coordinates physiologic flux of all three basic cellular nutrients: glucose, amino acids, and lipids.
Collapse
Affiliation(s)
- Saptarsi M Haldar
- Harrington Heart and Vascular Institute and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Case Medical Center, Cleveland, OH 44106, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
77
|
Pathobiochemical changes in diabetic skeletal muscle as revealed by mass-spectrometry-based proteomics. J Nutr Metab 2012; 2012:893876. [PMID: 22523676 PMCID: PMC3317182 DOI: 10.1155/2012/893876] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 12/09/2011] [Accepted: 12/19/2011] [Indexed: 12/13/2022] Open
Abstract
Insulin resistance in skeletal muscle tissues and diabetes-related muscle weakness are serious pathophysiological problems of increasing medical importance. In order to determine global changes in the protein complement of contractile tissues due to diabetes mellitus, mass-spectrometry-based proteomics has been applied to the investigation of diabetic muscle. This review summarizes the findings from recent proteomic surveys of muscle preparations from patients and established animal models of type 2 diabetes. The potential impact of novel biomarkers of diabetes, such as metabolic enzymes and molecular chaperones, is critically examined. Disease-specific signature molecules may be useful for increasing our understanding of the molecular and cellular mechanisms of insulin resistance and possibly identify new therapeutic options that counteract diabetic abnormalities in peripheral organ systems. Importantly, the biomedical establishment of biomarkers promises to accelerate the development of improved diagnostic procedures for characterizing individual stages of diabetic disease progression, including the early detection of prediabetic complications.
Collapse
|
78
|
Abstract
Macrophages are key innate immune effector cells best known for their role as professional phagocytes, which also include neutrophils and dendritic cells. Recent evidence indicates that macrophages are also key players in metabolic homoeostasis. Macrophages can be found in many tissues, where they respond to metabolic cues and produce pro- and/or anti-inflammatory mediators to modulate metabolite programmes. Certain metabolites, such as fatty acids, ceramides and cholesterol crystals, elicit inflammatory responses through pathogen-sensing signalling pathways, implicating a maladaptation of macrophages and the innate immune system to elevated metabolic stress associated with overnutrition in modern societies. The outcome of this maladaptation is a feedforward inflammatory response leading to a state of unresolved inflammation and a collection of metabolic pathologies, including insulin resistance, fatty liver, atherosclerosis and dyslipidaemia. The present review summarizes what is known about the contributions of macrophages to metabolic diseases and the signalling pathways that are involved in metabolic stress-induced macrophage activation. Understanding the role of macrophages in these processes will help us to develop therapies against detrimental effects of the metabolic syndrome.
Collapse
|
79
|
Manosroi J, Moses ZZ, Manosroi W, Manosroi A. Hypoglycemic activity of Thai medicinal plants selected from the Thai/Lanna Medicinal Recipe Database MANOSROI II. JOURNAL OF ETHNOPHARMACOLOGY 2011; 138:92-98. [PMID: 21925259 DOI: 10.1016/j.jep.2011.08.049] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 08/20/2011] [Accepted: 08/22/2011] [Indexed: 05/31/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Five medicinal plants including Anogeissus acuminata (Roxb. ex DC.) Gills. & Perr. (Combretaceae), Catunaregam tormentosa (Bl. ex DC.) Tirveng (Rubiaceae), Dioecrescis erythroclada (Kurz) Tirveng. (Rubiaceae), Mimosa pudica Linn. var. hispida Bren. (Fabaceae), and Rauwolfia serpentina (L). Benth. ex Kurz. (Apocyanaceae), which have been traditionally used for the treatment of diabetes mellitus and other diseases for several generations by the Thai-Lanna people in the Northern part of Thailand were investigated for their hypoglycemic activity in normoglycemic and alloxan, induced diabetic mice. MATERIALS AND METHODS The aqueous extracts of the selected five medicinal plants were tested for their phytochemicals, free radical scavenging activity and hypoglycemic activity on 18 h fasted normoglycemic and alloxan induced diabetic mice over a period of 4h comparing with the standard anti-diabetic drugs (insulin and glibenclamide) using two way analysis of variance (ANOVA) as analytical tool. Phytochemical analysis was performed using the standard methods while 2,2-diphenyl-1-picrylhydrazine (DPPH) was used to test for free radical scavenging activities of the medicinal plant extracts. RESULTS Phytochemicals detected in the extracts were glycosides, xanthones, tannins, alkaloids and saponins. Anogeissus acuminata showed the highest free radical scavenging activity with the IC(50) value of 11.00 μg/mL which was 4 folds of the standard ascorbic acid. Significant reduction in fasting blood glucose (FBG) levels of the normoglycemic mice was observed at 4 and 3h with the extracts of Mimosa pudica (200mg/kg bw) and Rauwolfia serpentina (100mg/kg bw), and percentage decreases of 46.15 and 27.94% which were 0.76 and 1.47; 0.53 and 0.91 folds of insulin and glibenclamide, respectively. In alloxan induced diabetic mice, all extracts showed significant (p<0.05) hypoglycemic activity, with the maximum FBG reduction of 78.96 at 100mg/kg bw shown by Anogeissus acuminata at the 4h. The hypoglycemic activity of Anogeissus acuminata was comparable to insulin (1.1 fold), but more potent than glibenclamide (1.76 folds). CONCLUSIONS Medicinal plants selected from the Thai/Lanna Medicinal Plant Recipe Database MANOSROI II showed hypoglycemic activity in normoglycemic and alloxan induced diabetic mice. This study confirmed the traditional use of these medicinal plants for the treatment of diabetes mellitus and the thiazolidiendiones mimic hypoglycemic effects of the medicinal plants was suggested.
Collapse
Affiliation(s)
- Jiradej Manosroi
- Natural Products Research and Development Center (NPRDC), Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200, Thailand.
| | | | | | | |
Collapse
|
80
|
Haus JM, Solomon TPJ, Lu L, Jesberger JA, Barkoukis H, Flask CA, Kirwan JP. Intramyocellular lipid content and insulin sensitivity are increased following a short-term low-glycemic index diet and exercise intervention. Am J Physiol Endocrinol Metab 2011; 301:E511-6. [PMID: 21712533 PMCID: PMC3174532 DOI: 10.1152/ajpendo.00221.2011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 06/27/2011] [Indexed: 12/31/2022]
Abstract
The relationship between intramyocellular (IMCL) and extramyocellular lipid (EMCL) accumulation and skeletal muscle insulin resistance is complex and dynamic. We examined the effect of a short-term (7-day) low-glycemic index (LGI) diet and aerobic exercise training intervention (EX) on IMCL and insulin sensitivity in older, insulin-resistant humans. Participants (66 ± 1 yr, BMI 33 ± 1 kg/m(2)) were randomly assigned to a parallel, controlled feeding trial [either an LGI (LGI/EX, n = 7) or high GI (HGI/EX, n = 8) eucaloric diet] combined with supervised exercise (60 min/day, 85% HR(max)). Insulin sensitivity was determined via 40 mU·m(-2)·min(-1) hyperinsulinemic euglycemic clamp and soleus IMCL and EMCL content was assessed by (1)H-MR spectroscopy with correction for fiber orientation. BMI decreased (kg/m(2) -0.6 ± 0.2, LGI/EX; -0.7 ± 0.2, HGI/EX P < 0.0004) after both interventions with no interaction effect of diet composition. Clamp-derived insulin sensitivity increased by 0.91 ± 0.21 (LGI/EX) and 0.17 ± 0.55 mg·kg(-1)·min(-1) (HGI/EX), P = 0.04 (effect of time). HOMA-IR was reduced by -1.1 ± 0.4 (LGI/EX) and -0.1 ± 0.2 (HGI/EX), P = 0.007 (effect of time), P = 0.02 (time × trial). Although both interventions increased IMCL content, (Δ: 2.3 ± 1.3, LGI/EX; 1.4 ± 0.9, HGI/EX, P = 0.03), diet composition did not significantly effect the increase. However, the LGI/EX group showed a robust increase in the [IMCL]/[EMCL] ratio compared with the HGI/EX group (Δ: 0.5 ± 0.2 LGI/EX vs. 0.07 ± 0.1, P = 0.03). The LGI/EX group also demonstrated greater reductions in [EMCL] than the HGI/EX group (Δ: -5.8 ± 3.4, LGI/EX; 2.3 ± 1.1, HGI/EX, P = 0.03). Changes in muscle lipids and insulin sensitivity were not correlated; however, the change in [IMCL]/[EMCL] was negatively associated with the change in FPI (r = -0.78, P = 0.002) and HOMA-IR (r = -0.61, P = 0.03). These data suggest that increases in the IMCL pool following a low glycemic diet and exercise intervention may represent lipid repartitioning from EMCL. The lower systemic glucose levels that prevail while eating a low glycemic diet may promote redistribution of lipid stores in the muscle.
Collapse
Affiliation(s)
- Jacob M Haus
- Dept. of Pathobiology, Lerner Research Institute, Cleveland Clinic, OH 44195, USA
| | | | | | | | | | | | | |
Collapse
|
81
|
Farr JN, Funk JL, Chen Z, Lisse JR, Blew RM, Lee VR, Laudermilk M, Lohman TG, Going SB. Skeletal muscle fat content is inversely associated with bone strength in young girls. J Bone Miner Res 2011; 26:2217-25. [PMID: 21544865 PMCID: PMC4414314 DOI: 10.1002/jbmr.414] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Childhood obesity is an established risk factor for metabolic disease. The influence of obesity on bone development, however, remains controversial and may depend on the pattern of regional fat deposition. Therefore, we examined the associations of regional fat compartments of the calf and thigh with weight-bearing bone parameters in girls. Data from 444 girls aged 9 to 12 years from the Jump-In: Building Better Bones study were analyzed. Peripheral quantitative computed tomography (pQCT) was used to assess bone parameters at metaphyseal and diaphyseal sites of the femur and tibia along with subcutaneous adipose tissue (SAT, mm(2) ) and muscle density (mg/cm(3) ), an index of skeletal muscle fat content. As expected, SAT was positively correlated with total-body fat mass (r = 0.87-0.89, p < .001), and muscle density was inversely correlated with total-body fat mass (r = -0.24 to -0.28, p < .001). Multiple linear regression analyses with SAT, muscle density, muscle cross-sectional area, bone length, maturity, and ethnicity as independent variables showed significant associations between muscle density and indices of bone strength at metaphyseal (β = 0.13-0.19, p < .001) and diaphyseal (β = 0.06-0.09, p < .01) regions of the femur and tibia. Associations between SAT and indices of bone strength were nonsignificant at all skeletal sites (β = 0.03-0.05, p > .05), except the distal tibia (β = 0.09, p = .03). In conclusion, skeletal muscle fat content of the calf and thigh is inversely associated with weight-bearing bone strength in young girls.
Collapse
Affiliation(s)
- Joshua N. Farr
- Department of Physiological Sciences, University of Arizona, Tucson, AZ, USA
| | - Janet L. Funk
- Department of Medicine, University of Arizona, Tucson, AZ, USA
| | - Zhao Chen
- Department of Epidemiology and Biostatistics, University of Arizona, Tucson, AZ, USA
| | | | - Robert M. Blew
- Department of Physiological Sciences, University of Arizona, Tucson, AZ, USA
| | - Vinson R. Lee
- Department of Physiological Sciences, University of Arizona, Tucson, AZ, USA
| | - Monica Laudermilk
- Department of Nutritional Sciences, University of Arizona, Tucson, AZ, USA
| | - Timothy G. Lohman
- Department of Physiological Sciences, University of Arizona, Tucson, AZ, USA
| | - Scott B. Going
- Department of Nutritional Sciences, University of Arizona, Tucson, AZ, USA
| |
Collapse
|
82
|
Stephens NA, Skipworth RJE, Macdonald AJ, Greig CA, Ross JA, Fearon KCH. Intramyocellular lipid droplets increase with progression of cachexia in cancer patients. J Cachexia Sarcopenia Muscle 2011; 2:111-117. [PMID: 21766057 PMCID: PMC3117997 DOI: 10.1007/s13539-011-0030-x] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 05/11/2011] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND: Intramyocellular lipids are an important source of fuel for mitochondrial fat oxidation and play an important role in intramuscular lipid homeostasis. We hypothesised that due to the phenotype associated with cancer cachexia, there would exist an association between increasing weight loss and the number/size of intramyocellular lipid droplets. METHODS: Nineteen cancer patients and 6 controls undergoing surgery were recruited. A rectus abdominis biopsy was performed and processed for transmission electron microscopy (TEM). The number of intramyocellular lipid droplets and lipid droplet diameter were calculated from the TEM images. CT scans, performed as part of patients' routine care, were analysed to determine amount of adipose (intermuscular, visceral and subcutaneous) and muscle tissue. RESULTS: Compared with controls, cancer patients had increased numbers of lipid droplets (mean (SD) 1.8 (1.9) vs. 6.4 (9.1) per ×2,650 field, respectively, p = 0.036). Mean (SD) lipid droplet diameter was also higher in cancer patients compared with controls (0.42 (0.13) vs. 0.24 (0.21) μm, p = 0.015). Mean lipid droplet count correlated positively with the severity of weight loss (R = 0.51, p = 0.025) and negatively with CT-derived measures of intermuscular fat (R = -0.53, p = 0.022) and visceral fat (R = -0.51, p = 0.029). CONCLUSIONS: This study suggests that the number and size of intramyocellular lipid droplets is increased in the presence of cancer and increases further with weight loss/loss of adipose mass in other body compartments.
Collapse
Affiliation(s)
- Nathan A Stephens
- Department of Clinical and Surgical Sciences (Surgery), School of Clinical Sciences and Community Health, University of Edinburgh, Royal Infirmary, 51 Little France Crescent, Edinburgh, EH16 4SA UK
| | | | | | | | | | | |
Collapse
|
83
|
Shaw CS, Cooper NM, Shaw O, Salomao P, Wagenmakers AJM. Acute high-fat feeding does not prevent the improvement in glucose tolerance after resistance exercise in lean individuals. Eur J Appl Physiol 2011; 111:2607-13. [PMID: 21380544 DOI: 10.1007/s00421-011-1872-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 02/11/2011] [Indexed: 12/13/2022]
Abstract
Our first aim was to investigate whether the ingestion of a single high-fat meal impairs glucose tolerance. Our second aim was to investigate whether improvements in glucose tolerance that are seen after resistance exercise remain when exercise is performed after ingestion of a high-fat meal. Eight young males consumed either a high fat (HF) or an isocaloric control (CON) meal in the morning and underwent an oral glucose tolerance test (OGTT) 6 h later. On two other occasions, a single 1 h bout of resistance exercise was completed 2 h after consumption of each meal (HFE and CONE). There were no significant differences in plasma glucose and plasma insulin areas under the curve (AUC) or estimates of insulin sensitivity between the HF and CON trials (P > 0.05). The HFE and CONE trials elicited a ~20% lower plasma glucose AUC (P < 0.05) compared to their respective control trials. The HFE also elicited a ~25% lower plasma insulin AUC (P < 0.05) in comparison to the HF trial. The HFE trial also significantly improved estimates of insulin sensitivity in comparison to the HF condition (P < 0.05). In conclusion, this study demonstrates that consumption of a single HF meal does not impair glucose tolerance in the resting state in lean individuals and that an acute bout of resistance exercise remains effective in enhancing glucose tolerance following the ingestion of a single high-fat meal.
Collapse
Affiliation(s)
- Christopher S Shaw
- Exercise Metabolism Research Group, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
| | | | | | | | | |
Collapse
|
84
|
Sopher R, Nixon J, Gorecki C, Gefen A. Effects of Intramuscular Fat Infiltration, Scarring, and Spasticity on the Risk for Sitting-Acquired Deep Tissue Injury in Spinal Cord Injury Patients. J Biomech Eng 2011; 133:021011. [DOI: 10.1115/1.4003325] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Sitting-acquired deep tissue injury (DTI) is a severe form of pressure ulcer (PU) often affecting patients with spinal cord injury (SCI) who also tend to suffer from intramuscular fat infiltration, soft tissue scarring (due to previous PU), and/or muscle spasticity in their buttocks. We previously used finite element (FE) modeling to evaluate whether abnormal bodyweight is a risk factor for sitting-acquired DTI. Here we hypothesize that fat infiltration, scarring, or spasms increase internal loads in the gluteus muscles in the vicinity of the ischial tuberosities during sitting, which consequently put SCI patients with these conditions at a higher risk for DTI. Our objective was to determine changes in gluteal strains and stresses and tissue volumes exposed to elevated strains/stresses associated with these factors. Thirty-five FE models of coronal slices through the seated buttocks, simulating these conditions at different severities, were developed. We calculated peak strains and stresses in glutei and percentage volumes of muscle tissue exposed to above-critical strains/stresses (compression strain≥50%, compression/von Mises stress≥2 kPa, and strain energy density≥0.5 kPa). Progressive intramuscular fat infiltration increased all the aforementioned outcome measures. Increase in size of scar patterns that were contained in both muscle and fat tissues similarly elevated the outcome measures. Spasms increased muscle stresses and volumetric exposures to stress, but tissue volumes at risk were ∼1–2% and increases due to spasticity were slight. We conclude that the above potential risk factors can be listed according to the following order of importance: (i) fat infiltration, (ii) scars contained in both muscle and fat tissues, and (iii) spasms. This information should be considered when prioritizing prevention means and resources for patients with SCI.
Collapse
Affiliation(s)
- Ran Sopher
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Jane Nixon
- Clinical Trials Research Unit, University of Leeds, Leeds LS2 9PH, UK
| | - Claudia Gorecki
- Clinical Trials Research Unit, University of Leeds, Leeds LS2 9PH, UK
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| |
Collapse
|