PT  - JOURNAL ARTICLE
AU  - L S Lohmander
AU  - T Saxne
AU  - D K Heinegård
TI  - Release of cartilage oligomeric matrix protein (COMP) into joint fluid after knee injury and in osteoarthritis.
AID  - 10.1136/ard.53.1.8
DP  - 1994 Jan 01
TA  - Annals of the Rheumatic Diseases
PG  - 8--13
VI  - 53
IP  - 1
4099  - http://ard.bmj.com/content/53/1/8.short
4100  - http://ard.bmj.com/content/53/1/8.full
SO  - Ann Rheum Dis1994 Jan 01; 53
AB  - OBJECTIVE--The release of fragments of cartilage oligomeric matrix protein (COMP) and aggrecan into knee joint fluid and serum after joint injury and in post-traumatic and primary osteoarthritis was monitored in a cross-sectional study. METHODS--Samples of joint fluid and serum were obtained from healthy volunteers and from patients with arthroscopically verified injury to anterior cruciate ligament and or meniscus of the knee at different times after injury and with different degrees of post-traumatic osteoarthritis. Samples were also obtained from patients with primary osteoarthritis. Fragments of COMP were quantified in joint fluid and in serum by enzyme-linked immunoassay. Fragments of aggrecan were quantified in joint fluid by enzyme-linked immunoassay. RESULTS--Concentrations of COMP and aggrecan fragments in joint fluid in the study groups were increased over the reference levels of 47 (range 10-109) and 34 (range 6-59) micrograms/mL, respectively, in the volunteers with healthy knees. The ratios (w/w) of aggrecan to COMP fragments in joint fluid were also increased in all study groups over that in the reference group. Average concentrations of COMP in joint fluid were high shortly after injury and decreased with time but remained increased over reference levels for many years. Joint fluid COMP concentrations were also increased in early stage post-traumatic and primary osteoarthritis, but not in advanced osteoarthritis. CONCLUSION--Increased amounts of aggrecan and COMP fragments are released into joint fluid after joint injury and in early stage osteoarthritis. The ratios of aggrecan to COMP in joint fluid vary with time after injury and with osteoarthritis disease stage. Although both molecules are sensitive to the agents active in matrix breakdown in joint disease, differences may thus exist in the release mechanisms and attempted repair. The concentrations of the individual markers in body fluids and their ratios may serve to monitor treatment efficacy, disease progression and repair in osteoarthritis and other joint diseases.