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Impact of knee joint loading on fragmentation of serum cartilage oligomeric matrix protein |
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| Authors: | Sara Firner Frank Zaucke Juliane Heilig Markus de Marées Steffen Willwacher Gert-Peter Brüggemann Anja Niehoff |
| Affiliation: | 1. Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne, Germany;2. Dr. Rolf M. Schwiete Research Unit for Osteoarthritis, Orthopedic University Hospital Friedrichsheim gGmbH, Frankfurt, Germany;3. Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany;4. Department of Sports Medicine and Sports Nutrition, Faculty of Sport Science, Ruhr-University Bochum, Bochum, Germany;5. Institute of Biomechanics and Orthopaedics, German Sport University Cologne, Cologne, Germany Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany |
| Abstract: | The aim of the study was to examine the effect of mechanical knee joint loading on the fragmentation pattern of serum cartilage oligomeric matrix protein (COMP). Ten healthy men ran with knee orthoses that were passive or active (+30.9 N·m external flexion moments) on a treadmill (30 minute; v = 2.2 m/s). Lower-limb mechanics, serum COMP levels, and fragmentation patterns (baseline; 0, 0.5, 1, 2 hours postrunning) were analyzed. Running with active orthoses enhanced knee flexion moments, ankle dorsiflexion, and knee flexion angles (P < .05). There was an increase in serum COMP (+25%; pre: 8.9 ± 2.4 U/l; post: 10.7 ± 1.9 U/l, P = .001), COMP pentamer/tetramer (+88%; 1.88 ± 0.81, P = .007), trimer (+209%; 3.09 ± 2.65, P = .005), and monomer (+78%; 1.78 ± 0.85, P = .007) after running with passive orthoses and in serum COMP (+41%; pre: 8.5 ± 2.7 U/l; post: 11.3 ± 2.1 U/l, P < .001), COMP pentamer/tetramer (+57%; 1.57 ± 0.39, P = .007), trimer (+86%; 1.86 ± 0.47, P = .005), and monomer (+19%; 1.19 ± 0.34, P = .114) after running with active orthoses. Increased fragmentation might indicate COMP release from cartilage while running. Interestingly, 0.5 h up to 2 hours after running with passive orthoses, trimer (0.5 hour: 2.73 ± 3.40, P = .029; 2 hours: 2.33 ± 2.88, P = .037), and monomer (0.5 hour: 2.23 ± 2.33, P = .007; 1 hour: 2.55 ± 1.96, P = .012; 2 hours: 2.65 ± 2.50, P = .009) increased while after running with active orthoses, pentamer/tetramer (1 hour: 0.79 ± 0.28, P = .029), and trimer (1 hour: 0.63 ± 0.14, P = .005; 2 hours: 0.68 ± 0.34, P = .047) decreased. It seems that COMP degradation and clearance vary depending on joint loading characteristics. |
| Keywords: | cartilage COMP fragmentation pattern mechanical joint loading western blot |