COMPARISON OF MATRIX VESICLES DERIVED FROM NORMAL AND OSTEOARTHRITIC HUMAN ARTICULAR-CARTILAGE

Articular cartilage matrix vesicles (MVs) from normal human adult arti cular cartilage were examined for protein and enzyme content and biomi neralizing capacity for comparison to MVs derived from human osteoarth ritic (OA) cartilage, Femoral condylar and tibial plateau cartilage fr om each of 9 healthy donors ages 17-37y was enzymatically digested and serially ultracentrifuged to pellet MV's at 3 x 10(6) g-min. MV prote in content, nucleoside triphosphate pyrophospho hydrolase (NTPPPH) spe cific activity (SA) and capacity for Ca-45 precipitation were determin ed, MV precipitated mineral was examined using Fourier transform infra red spectroscopy (FTIR), Normal human cartilage yields 50% less MV pro tein/g cartilage than OA cartilage (p < .01), Normal human articular M Vs possess 30-70x higher NTPPPH SA than cell-free digest. Mean NTPPPH SAs of MVs derived from normal human cartilage are 3x higher than that of OA MVs (p < .05) and normal MV NTPPPH SA appears to decrease with age (p < .01), Normal human MVs support significantly higher calcium p recipitation/mg MV protein in both ATP-dependent (p < .01) and -indepe ndent (p = .05) systems, The FTIR spectrum of hn mineral generated in the presence of ATP strongly resembles the standard spectrum for calci um pyrophosphate dihydrate (CPPD), The FTIR spectrum of MV mineral gen erated without ATP resembles that of carbonate-substituted apatite (AP ), The fact that isolated MVs from normal cartilage generate pathologi cally relevant crystal phases in vitro implies that matrix integrity a nd substrate availability may be crucial factors in the control of pat hologic biomineralization.