title: Proteomics perspectives in rotator cuff research: a systematic review of gene expression and protein composition in human tendinopathy.
abstract: BACKGROUND
  Rotator cuff tendinopathy including tears is a cause of significant morbidity. The molecular pathogenesis of the disorder is largely unknown. This review aimed to present an overview of the literature on gene expression and protein composition in human rotator cuff tendinopathy and other tendinopathies, and to evaluate perspectives of proteomics--the comprehensive study of protein composition--in tendon research.
  
  
  METHODS
  We conducted a systematic search of the literature published between 1 January 1990 and 18 December 2012 in PubMed, Embase, and Web of Science. We included studies on objectively quantified differential gene expression and/or protein composition in human rotator cuff tendinopathy and other tendinopathies as compared to control tissue.
  
  
  RESULTS
  We identified 2199 studies, of which 54 were included; 25 studies focussed on rotator cuff or biceps tendinopathy. Most of the included studies quantified prespecified mRNA molecules and proteins using polymerase chain reactions and immunoassays, respectively. There was a tendency towards an increase of collagen I (11 of 15 studies) and III (13 of 14), metalloproteinase (MMP)-1 (6 of 12), -9 (7 of 7), -13 (4 of 7), tissue inhibitor of metalloproteinase (TIMP)-1 (4 of 7), and vascular endothelial growth factor (4 of 7), and a decrease in MMP-3 (10 of 12). Fourteen proteomics studies of tendon tissues/cells failed inclusion, mostly because they were conducted in animals or in vitro.
  
  
  CONCLUSIONS
  Based on methods, which only allowed simultaneous quantification of a limited number of prespecified mRNA molecules or proteins, several proteins appeared to be differentially expressed/represented in rotator cuff tendinopathy and other tendinopathies. No proteomics studies fulfilled our inclusion criteria, although proteomics technologies may be a way to identify protein profiles (including non-prespecified proteins) that characterise specific tendon disorders or stages of tendinopathy. Thus, our results suggested an untapped potential for proteomics in tendon research.
authors: Danish Ramazzini Centre, Department of Occupational Medicine, Regional Hospital West Jutland-University Research Clinic, Herning, Denmark.
authors: Maria Hee Jung
authors: MH
authors: Sejersen
authors: Danish Ramazzini Centre, Department of Occupational Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors: Poul
authors: P
authors: Frost
authors: Research Unit for Orthopaedics, Holstebro Regional Hospital, Holstebro, Denmark; Institute of Clinical Medicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark.
authors: Torben Bæk
authors: TB
authors: Hansen
authors: Department of Orthopaedic Surgery, Randers Regional Hospital, Randers, Denmark.
authors: Søren Rasmussen
authors: SR
authors: Deutch
authors: Danish Ramazzini Centre, Department of Occupational Medicine, Regional Hospital West Jutland-University Research Clinic, Herning, Denmark.
authors: Susanne Wulff
authors: SW
authors: Svendsen
mesh_terms: D015870:Gene Expression; D006801:Humans; D011506:Proteins / Q000378:metabolism*; D040901:Proteomics; D017594:Publication Bias; D017006:Rotator Cuff / Q000378:metabolism*; D019534:Shoulder Impingement Syndrome / Q000378:metabolism*
chemical_list: D011506:Proteins