Accumulation of mitochondrial DNA with 4977-bp deletion in knee cartilage - an association with idiopathic osteoarthritis

Objective: Since mitochondrial DNA (mtDNA) mutations have been established to associate with the aging process and some degenerative diseases, we investigated the correlation between idiopathic osteoarthritis (OA) and the 4977-bp mtDNA deletion. Design: Cartilage were collected from six sites in knee joints removed from 18 aged patients with idiopathic OA, 10 aged non-OA cadavers, 3 young cadavers (YC), and lateral femoral condyle of 9 young patients. Histopathologic changes were examined and the common 4977-bp mtDNA deletions were analyzed in young and elderly cartilages obtained from different sites in the knee joint. The association of the 4977-bp deletion of mtDNA with idiopathic CA and aging was evaluated. Results: The 4977-bp mtDNA deletion was detected in 17 of the 18 OA patients, 9 of the 10 aged non-OA cadavers, and 1 of the 3 YC. None of the nine specimens collected from the lateral femoral condyle of young patients had a detectable deletion of mtDNA. The 4977-bp mtDNA deletion was not significantly correlated with the severity of CA graded by the Mankin score. The frequencies of occurrence of the 4977-bp mtDNA deletion were significantly different between the CA group and the aged non-OA control group (P = 0.004) and between the aged non-CA group and the young control group (P = 0.002). Conclusions: The results suggest that accumulation of the 4977-bp deletion of mtDNA in knee cartilage increases with age and may play a role in the development of idiopathic CA in the knee joint. (c) 2005 OsteoArthrits Research Society International. Published by Elsevier Ltd. All rights reserved.