Roles of chondrocytes in the pathogenesis of osteoarthritis.

Recent investigations into the striking heterogeneity of cellular reaction patterns that are characteristic for, and puzzling in, osteoarthritic cartilage degeneration addressed apoptotic cell death of the chondrocytes and its underlying mechanisms. Also, chondrocyte senescence in terms of telomere reduction was reported to correlate with cartilage degeneration. Pathways of anabolic and catabolic activity of the cells as well as mechanisms for phenotypic instability of chondrocytes were further characterized. The mechanoregulation of the cartilage cells appears to be centrally involved in all these processes, in particular cell death and anabolic activity. Methodologically, the past year has seen the first steps of functional genomics in osteoarthritis research, providing new insights into the cell biology of this condition.