Tumor necrosis factor-alpha receptor expression on chondrocytes isolated from human articular cartilage.
OBJECTIVE
To determine whether the previously observed enhanced susceptibility of osteoarthritic (OA) cartilage to tumor necrosis factor-alpha (TNF-alpha) induced degradation could be due to differences in receptor expression.


METHODS
Using specific monoclonal antibodies flow cytometry was used to identify and quantify 2 TNF-alpha receptors on the surface of chondrocytes isolated from human articular cartilage.


RESULTS
The proportion of chondrocytes expressing p55 TNF-alpha receptor was significantly higher in populations from OA cartilage (p < 0.01) when compared with similar populations from non-arthritic cartilage. The number of p55 receptors/chondrocyte was also significantly higher (p < 0.01) in OA. A significant correlation (r = 0.72, p < 0.18) was found in OA between the numbers of chondrocytes expressing p75 receptor and the number of receptors/chondrocyte.


CONCLUSIONS
p55 TNF-alpha receptor expression is significantly increased on OA chondrocytes ex vivo. Enhanced expression of p55, purported to be the biologically active receptor, could contribute to OA cartilage degradation.
Westacott
C I
CI
Department of Pathology, University of Bristol, UK.
Atkins
R M
RM
Dieppe
P A
PA
Elson
C J
CJ
D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD; D002358:Cartilage, Articular / Q000737:chemistry*; D002469:Cell Separation; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism* / Q000473:pathology; D018124:Receptors, Tumor Necrosis Factor / Q000032:analysis*; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D012995:Solubility
D015703:Antigens, CD; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II