Type II collagen C2C epitope in human synovial fluid and serum after knee injury – associations with molecular and structural markers of injury. Issue 9 (September 2015)

• Record Type: Journal Article
• Authors: Kumahashi, N.; Swärd, P.; Larsson, S.; Lohmander, L.S.; Frobell, R.; Struglics, A.
• Is Part Of: Osteoarthritis and cartilage. Volume 23:Issue 9(2015)
• Page Start: 1506
• Page End: 1512
• Publication Date: 2015-09
• Subjects: Biomarkers -- Collagen -- C2C -- Knee injury -- Synovial fluid; Osteoarthritis -- Periodicals; Cartilage -- Periodicals; Osteoarthritis -- Periodicals; Cartilage -- Periodicals; Arthrose -- Périodiques; Articulations -- Maladies -- Périodiques; 616.7223005
• DOI: 10.1016/j.joca.2015.04.022
• Languages: English
• ISSNs: 1063-4584

Abstract

Summary: Purpose: Investigate in a cross-sectional study time-dependent changes of synovial fluid type II collagen epitope C2C concentrations after knee injury and correlate to other joint injury biomarkers. Methods: Synovial fluid samples were aspirated between 0 days and 7 years after injury ( n = 235). Serum was collected from 71 of the knee injured patients. Synovial fluid from 8 knee-healthy subjects was used as reference. C2C was quantified by immunoassay and structural injury was determined from magnetic resonance images (MRI) of the injured knee acquired 1–38 days after injury ( n = 98). Additional joint injury biomarker results were from earlier investigations of the same samples. Results: Synovial fluid C2C concentrations were higher in injured knees than in knees of reference subjects from 1 day up to 7 years after injury. C2C concentrations in synovial fluid and serum were correlated ( r = 0.403, P < 0.001). In synovial fluid from subjects early after injury (0–33 days), C2C concentrations were correlated with cross-linked C-telopeptide of type II collagen ( r = 0.444, P = 0.003), ARGS-aggrecan ( r = 0.337, P < 0.001), osteocalcin ( r = 0.345, P < 0.001), osteopontin ( r = 0.371, P < 0.001) and IL-8 ( r = −0.385, P < 0.001), but not with structural joint injury as visualized on MRI. Conclusion: The increased levels of synovial fluid C2C after injury, together with the associations seen with several other injury-related biomarkers, suggest that an acute knee injury is associated with an immediate and sustained local degradation of type II collagen.