title: Investigation of skeletal muscle quantity and quality in end-stage renal disease.
abstract: OBJECTIVE
  A more precise understanding of the aetiology and sequelae of muscle wasting in end-stage renal disease (ESRD) is required for the development of effective interventions to target this pathology.
  
  
  METHODS
  We investigated 49 patients with ESRD (62.6 +/- 14.2 years, 0.3-16.7 years on haemodialysis). Thigh muscle cross-sectional area (CSA), intramuscular lipid and intermuscular adipose tissue (IMAT) were measured via computed tomography as indices of muscle quantity (i.e. CSA) and quality (i.e. intramuscular lipid and IMAT). Additional health and clinical measures were investigated to determine associations with these variables.
  
  
  RESULTS
  Age, energy intake, disease burden, pro-inflammatory cytokines, nutritional status, strength and functioning were related to muscle quantity and quality. Potential aetiological factors entered into forward stepwise regression models indicated that hypoalbuminaemia and lower body mass index accounted significantly and independently for 32% of the variance in muscle CSA (r = 0.56, P < 0.001), while older age and interleukin-8 accounted for 41% of the variance in intramuscular lipid (r = 0.64, P < 0.001) and body mass index accounted for 45% of the variance in IMAT (r = 0.67, P < 0.001). Stepwise regression models revealed that intramuscular lipid was independently predictive of habitual gait velocity and 6 min walk distance, while CSA was independently predictive of maximal isometric strength (P < 0.05).
  
  
  CONCLUSIONS
  Ageing, poor nutritional status and elevated interleukin-8 are factors potentially contributing to the loss of muscle quality and quantity in ESRD. These deficits can predict functional impairments, with intramuscular lipid accumulation most closely related to decline of submaximal musculoskeletal performance (walking), and low muscle CSA most closely related to decline of maximal performance (peak isometric strength).
authors.affiliation: Exercise, Health and Performance Research Group, School of Biomedical and Health Sciences, University of Western Sydney, Locked Bag 1797, Penrith South DC, NSW 1797, Australia. b.cheema@uws.edu.au
authors.forename: Birinder
authors.initials: B
authors.lastname: Cheema
authors.forename: Haifa
authors.initials: H
authors.lastname: Abas
authors.forename: Benjamin
authors.initials: B
authors.lastname: Smith
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: O'Sullivan
authors.forename: Maria
authors.initials: M
authors.lastname: Chan
authors.forename: Aditi
authors.initials: A
authors.lastname: Patwardhan
authors.forename: John
authors.initials: J
authors.lastname: Kelly
authors.forename: Adrian
authors.initials: A
authors.lastname: Gillin
authors.forename: Glen
authors.initials: G
authors.lastname: Pang
authors.forename: Brad
authors.initials: B
authors.lastname: Lloyd
authors.forename: Klaus
authors.initials: K
authors.lastname: Berger
authors.forename: Bernhard T
authors.initials: BT
authors.lastname: Baune
authors.forename: Maria Fiatarone
authors.initials: MF
authors.lastname: Singh
mesh_terms: D050154:Adiposity; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007249:Inflammation / Q000150:complications; D007676:Kidney Failure, Chronic / Q000150:complications / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D050356:Lipid Metabolism; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D009133:Muscular Atrophy / Q000000981:diagnostic imaging / Q000209:etiology* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D009517:New South Wales; D009752:Nutritional Status; D006435:Renal Dialysis; D018570:Risk Assessment; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D016138:Walking