Grant: Operating Grant

Osteoarthritis (OA) is a debilitating disease of the joint. It affects approximately half of Canada's population aged sixty and older. It is associated with pain, joint stiffness, loss of muscle mass, impaired mobility, and it harms the quality of life of the elderly more than any other single disease. The causes leading to osteoarthritis remain unknown. However, it is generally believed that mechanical loading of the joints deforms articular cartilage cells, and that these cells provide the biological signals for maintaining healthy cartilage. If the mechanical loading of the cartilage and cells becomes non-physiological, cells are unable to maintain the cartilage matrix, the cartilage becomes soft and cell deformations increase, thereby disturbing equilibrium conditions, leading to joint degeneration and osteoarthritis. The purpose of our research is to understand the relationship of cartilage loading, cell deformations, and associated biological signaling of the cells. We developed sophisticated techniques to perform such studies for the first time with the cells fully embedded in the cartilage and with the cells in the intact joint, thereby guaranteeing that experimental artifacts associated with cartilage or cell isolation, approaches that have been used in the past, are eliminated. Pilot work has shown that cell mechanics and biology differ vastly between the traditional approaches and the more physiologically relevant approaches proposed here, suggesting that much of our present understanding of osteoarthritis may not hold for the intact joint.