title: Fibrosis, low vascularity, and fewer slow fibers after rotator-cuff injury.
abstract: Rotator-cuff injury (RCI) represents 50% of shoulder injuries, and prevalence increases with age. Even with successful tendon repair, muscle and joint function may not return.
  
  
  
  To explore the dysfunction, supraspinatus and ipsilateral deltoid (control) muscles were biopsied during arthroscopic RCI repair for pair-wise histological and protein-expression studies.
  
  
  
  Supraspinatus showed fiber atrophy (P <  0.0001), fibrosis (by Sirius Red, P = 0.05), reduced vascular density (P <  0.001), and a lower proportion of slow fibers (P <  0.0001) compared with the ipsilateral control muscle. There were also higher levels of atrogin-1 (P = 0.05), vascular endothelial growth factor (VEGF, P <  0.01), and dystrophin (P <  0.008, relative to fiber diameter) versus control.
  
  
  
  Adaptive changes in vascular endothelial growth factor and dystrophin were likely associated with reduced vascular supply, fatigue resistance, and fibrosis, accompanied by disuse atrophy from mechanical unloading of supraspinatus after tendon tear. Treatment to promote growth and vascularity in atrophic supraspinatus muscle may help improve functional outcome after surgical repair. Muscle Nerve 55: 715-726, 2017.
authors: Department of Biological Sciences, Faculty of Science, University of Manitoba, 212 Biological Sciences Building, 50 Sifton Road, Winnipeg, MB, R3T 2N2, Canada.
authors: Deanna
authors: D
authors: Gigliotti
authors: Faculty of Health Sciences College of Medicine Departments of Surgery (Orthopedics) at the University of Manitoba, Winnipeg, Canada.
authors: Mark C
authors: MC
authors: Xu
authors: Faculty of Health Sciences College of Medicine Department of Radiology at the University of Manitoba, Winnipeg, Canada.
authors: Michael J
authors: MJ
authors: Davidson
authors: Faculty of Health Sciences College of Medicine Departments of Surgery (Orthopedics) at the University of Manitoba, Winnipeg, Canada.|Pan Am Clinic, Winnipeg, Canada.
authors: Peter B
authors: PB
authors: Macdonald
authors: Faculty of Health Sciences College of Medicine Departments of Surgery (Orthopedics) at the University of Manitoba, Winnipeg, Canada.|Pan Am Clinic, Winnipeg, Canada.
authors: Jeff R S
authors: JRS
authors: Leiter
authors: Department of Biological Sciences, Faculty of Science, University of Manitoba, 212 Biological Sciences Building, 50 Sifton Road, Winnipeg, MB, R3T 2N2, Canada.
authors: Judy E
authors: JE
authors: Anderson
mesh_terms: D000368:Aged; D024722:Cardiac Myosins / Q000378:metabolism; D016189:Dystrophin / Q000378:metabolism; D005260:Female; D005355:Fibrosis / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008875:Middle Aged; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism / Q000473:pathology*; D009124:Muscle Proteins / Q000378:metabolism; D009133:Muscular Atrophy / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D018995:Myosin Heavy Chains / Q000378:metabolism; D000070636:Rotator Cuff Injuries / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D016189:Dystrophin; C501641:MYH7 protein, human; D009124:Muscle Proteins; D042461:Vascular Endothelial Growth Factor A; C440907:FBXO32 protein, human; D044843:SKP Cullin F-Box Protein Ligases; D020780:Matrix Metalloproteinase 9; D024722:Cardiac Myosins; D018995:Myosin Heavy Chains
keywords: MyHC1; VEGF; atrogin-1; disuse; fiber typing; supraspinatus