Change in serum COMP concentration due to ambulatory load is not related to knee OA status.
The aim of this study was to test the hypothesis that a change in serum cartilage oligomeric matrix protein (COMP) concentration is related to joint load during a 30-min walking exercise in patients with medial compartment knee osteoarthritis (OA) and in age-matched control subjects. Blood samples were drawn from 42 patients with medial compartment knee OA and from 41 healthy age-matched control subjects immediately before, immediately after, and 0.5, 1.5, 3.5, and 5.5 h after a 30-min walking exercise on a level outdoor walking track at self-selected normal speed. Serum COMP concentrations were determined using a commercial ELISA. Basic time-distance gait variables were recorded using an activity monitor. Joint loads were measured using gait analysis. Serum COMP concentrations increased immediately after the walking exercise (+6.3% and +5.6%; p < 0.001) and decreased over 5.5 h after the exercise (-11.1% and -14.6%; p < 0.040 and p = 0.001) in patients and control subjects, respectively. The magnitude of increase in COMP concentration did not differ between groups (p = 0.902) and did not correlate with any variables describing ambulatory loads at the joints of the lower extremity. These results, taken together with a previous study of a younger healthy population, suggest the possibility that the influence of ambulatory loads on cartilage turnover is dependent on age.
Department of Mechanical Engineering, Stanford University, Stanford, California, USA. anne.muendermann@gmail.com
Annegret
A
Mündermann
Karen B
KB
King
R Lane
RL
Smith
Thomas P
TP
Andriacchi
D000328:Adult; D000368:Aged; D064236:Cartilage Oligomeric Matrix Protein; D016326:Extracellular Matrix Proteins / Q000097:blood*; D005260:Female; D005684:Gait; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D008297:Male; D064235:Matrilin Proteins; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000097:blood*; D016138:Walking; D016474:Weight-Bearing
D064236:Cartilage Oligomeric Matrix Protein; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D064235:Matrilin Proteins; C577553:TSP5 protein, human