Collagen type VI content in. normal and osteoarthritic human knee cartilage.

Aim of the study: Since collagen type VI seems to play an important role in cartilage metabolism and is increased in osteoarthritis, the aim of this s tudy was to investigate whether different stages of osteoarthritis can be c haracterised by the content of collagen type VI in human knee cartilage. Ma terial and Methods: Collagen type VI was investigated in 148 histologically normal and 117 osteoarthritic cartilage samples from 18 different localisa tions of human knee joints. It was quantified in cartilage extracts using a n inhibition-ELISA. Results: In normal cartilage the average content of col lagen type VI was 0.48 per cent of total collagens. Interestingly, there wa s a high variability not only in osteoarthritic, but also in normal cartila ge. The statistical analysis showed significant differences between normal femoral, tibial or retropatellar cartilage samples. Therefore, normal and o steoarthritic samples from different localizations had to be compared separ ately. A significant increase of collagen type VI was already found in earl y osteoarthritic lesions. Conclusions: Inspite of a statistically significa nt increase of collagen type VI in osteoarthritic cartilage, the range of c oncentrations found in normal and osteoarthritic samples overlap. In view o f the high interindividual variability, collagen type VI is not very precis e in the diagnosis of early osteoarthritic lesions if used as the only mark er.