Cell Metabolism

Cure Arthritis Naturally

Cure Arthritis Naturally

Get Instant Access

Biological tissues undergo significant changes during the aging process. The metabolic response of chondrocytes changes with aging. For instance, with increasing age, articular cartilage chondrocytes become less responsive to anabolic cytokines (Martin and Buckwalter, 2000) presumably leading to reduced synthetic capacity (DeGroot et al., 1999) and activity (Bolton et al., 1999) of chondrocytes. Due to these changes in cell metabolism, the size of water-attracting proteoglycan aggregates decreases (Buckwalter et al., 1994), and consequently the water content also decreases with age (Venn, 1978). In contrast, collagen molecules have an extremely long half-life (>200 years; Maroudas et al. (1992)), and the total amount of collagen in cartilage does not decrease with age (Venn, 1978). However, with age, increasing numbers of cross-links between molecules form by nonenzymatic glycation (Bank et al., 1998).

The biological changes in cartilage with aging may be the cause for the overall altered mechanical properties of the tissue such as decreased tensile stiffness and strength (Kempson, 1982). Articular cartilage aging does not cause osteoarthritis, but the age-related metabolic and phenotypic decline of the chondrocytes increases the risk of articular cartilage degeneration and limits the ability of the cell to repair the tissue once degenerative changes occur (Martin and Buckwalter, 2002). Similar changes have been observed in menisci (McAlinden et al., 2001) and ligaments (Noyes and Grood, 1976; Woo et al., 1991).

In contrast to the natural aging process, osteoarthritis is associated with a prominent regenerative and repara-tive activity. More specifically, osteoarthritis is characterized by increased cell activity and cell proliferation, but also by hypertrophy and erosion of the tissue, focal defects, pericellular degradation and interterritorial matrix degradation, nonreversible proteoglycan depletion, mild focal superficial inflammation of the synovium, and subchondral remodeling. Cartilage changes in early osteoarthritis include chondrocyte proliferation, surface fibrillation, and perichondral collagen condensation. In advanced osteoarthritis, fissures extend to the midzone,

Normal Flaking

Normal Flaking

Figure 77.3 Illustration of the changes to the superficial zone of cartilage during the progression of osteoarthritis (OA). A. Normal cartilage shows a smooth surface; the early stage of OA is characterized by B. flaking of the surface; C. fibrillation; and D. the formation of a blister. The mechanical surface changes will increase the coefficient of friction at the surface. From Gannon and Sokoloff (1999).

Figure 77.3 Illustration of the changes to the superficial zone of cartilage during the progression of osteoarthritis (OA). A. Normal cartilage shows a smooth surface; the early stage of OA is characterized by B. flaking of the surface; C. fibrillation; and D. the formation of a blister. The mechanical surface changes will increase the coefficient of friction at the surface. From Gannon and Sokoloff (1999).

the matrix delaminates and erodes, fibrosis can be observed, and fibrocartilage is formed as a repair response (Pritzker, 2003).

Was this article helpful?

0 0
Natural Arthritis Pain Remedies

Natural Arthritis Pain Remedies

It's time for a change. Finally A Way to Get Pain Relief for Your Arthritis Without Possibly Risking Your Health in the Process. You may not be aware of this, but taking prescription drugs to get relief for your Arthritis Pain is not the only solution. There are alternative pain relief treatments available.

Get My Free Ebook


Post a comment