Aging processes and the development of osteoarthritis.

Purpose of review Aging is a primary risk factor for the development of osteoarthritis and the understanding of how aging processes contribute to the development of osteoarthritis is an important area of active research. The most recent literature in this area was reviewed in order to update investigators on the status of the field. Recent findings The field is beginning to move beyond a cartilage focus to include other joint tissues relevant to osteoarthritis such as ligaments, meniscus, and bone. Synovitis also appears to play a role in osteoarthritis but has not been a focus of aging studies. Studies in small animals, including mice and rats, demonstrate age-related changes that can contribute to osteoarthritis and show that animal age is a key factor to be considered in interpreting the results of studies using surgically induced models of osteoarthritis. There is accumulating evidence that cellular processes such as damage-induced cell senescence contribute to osteoarthritis and a growing body of literature on the role of epigenetic regulation of gene expression in aging and osteoarthritis. Summary Not all osteoarthritis is due to aging processes in joint tissues, but the age-related changes being discovered certainly could play a major contributing role.