title: High rate of joint capsule matrix turnover in chronic human elbow contractures.
abstract: The joint capsule is a key component in posttraumatic joint contractures. The capsule is described as thickened, but little data exist supporting the observation. Our hypotheses were that mRNA levels of (1) collagen; (2) decorin and biglycan; (3) matrix metalloproteinases; and (4) tissue inhibitors of matrix metalloproteinases were significantly elevated in anterior joint capsules obtained from 11 patients having surgery for posttraumatic contractures when compared with nine elbows, from organ donors, that were free of contractures. Reverse transcription-polymerase chain reaction was used to evaluate mRNA expression normalized to a housekeeping gene, glyceraldehyde-3-phosphate dehydrogenase. In the joint capsules of the patients with elbow contractures, relative mRNA levels were increased for: collagen Types I, III, and V (1.5-2.5 times); biglycan (1.5 times); and matrix metalloproteinases-1, -2, -9, -13, and -15 (1.6-3.9 times). In contrast, expression of tissue inhibitors of matrix metalloproteinases-1, -2, and -4 were decreased (1/3-3/4 times) in the capsules of patients with contractures. There was no difference between the groups in relative mRNA expression for decorin, matrix metalloproteinases-8, -14 and -16, and tissue inhibitor of matrix metalloproteinase-3. The results indicate that joint capsule matrix molecule mRNA levels are altered in the chronic stages of posttraumatic elbow contractures in humans, potentially creating an environment with high matrix turnover rates.
authors.affiliation: McCaig Centre for Joint Injury and Arthritis Research, University of Calgary, Calgary, Canada. hildebrk@ucalgary.ca
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Hildebrand
authors.forename: Mei
authors.initials: M
authors.lastname: Zhang
authors.forename: David A
authors.initials: DA
authors.lastname: Hart
mesh_terms: D000293:Adolescent; D000328:Adult; D058578:Biglycan; D002908:Chronic Disease; D024042:Collagen Type I / Q000235:genetics; D024061:Collagen Type III / Q000235:genetics; D024062:Collagen Type V / Q000235:genetics; D003286:Contracture / Q000473:pathology* / Q000503:physiopathology*; D004551:Elbow Joint / Q000473:pathology* / Q000503:physiopathology*; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D006801:Humans; D017746:Joint Capsule / Q000473:pathology / Q000503:physiopathology; D008297:Male; D020782:Matrix Metalloproteinases / Q000235:genetics; D008875:Middle Aged; D011509:Proteoglycans / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D019714:Tissue Inhibitor of Metalloproteinases / Q000235:genetics
chemical_list: C546884:BGN protein, human; D058578:Biglycan; D024042:Collagen Type I; D024061:Collagen Type III; D024062:Collagen Type V; D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D012333:RNA, Messenger; D019714:Tissue Inhibitor of Metalloproteinases; D020782:Matrix Metalloproteinases