Cartilage metabolism

Background

Cartilage is a strong, pliable, specialized connective tissue that is present in many bony areas of the body where flexibility is needed, such as joints and spinal discs. Cartilage serves many functions in the body, including helping the joints resist friction to move smoothly and absorbing shock from sports and trauma. Cartilage also helps support the shape of joints while connecting other tissues like muscles, tendons, and ligaments to each other and to bone. Cells called chondrocytes are the primary producers of cartilage, which exists in a matrix containing high levels of proteoglycans and glycosaminoglycans, giving cartilage its flexibility and elasticity.^1,2

There are three main types of cartilage: hyaline, elastic, and fibrocartilage.

Hyaline cartilage is the most abundant type of cartilage which lines the bones to form joints, connects the ribs to the sternum, and is found in the nasal passages. Composed of type II collagen, proteoglycans and water, it provides a layer that resists compressive forces and mitigates friction^1,2.

Elastic cartilage is found in parts of the body where increased flexibility is needed—at the entrance of the trachea and esophagus, at the vocal cords, and the external ear. It is similar to hyaline cartilage, but exhibits more elasticity^1,2.

Fibrocartilage is present in areas of the body that resist high levels of mechanical stress including the vertebrae, knee, and other joints where tendons and ligaments attach. It is abundant in type I collagen and contains less proteoglycans than hyaline cartilage^1,2.^1,2

Cartilage metabolism disorders

Disruption of the structural integrity of cartilage is the major histological finding in osteoarthritis and rheumatoid arthritis. Osteoarthritis is a chronic degenerative joint disease with cartilage degradation. It is the most common type of arthritis—it leads to pain, discomfort, and functional limitations due to “wear and tear” and thinning of cartilage. Rheumatoid arthritis is a systemic autoimmune rheumatic disorder in which the immune system attacks healthy joints—leading to painful swelling, inflammation, and stiffness. While osteoarthritis affects the whole joint, the hyaline cartilage is the most affected tissue of the disorder.² Early diagnosis of osteoarthritis remains a challenge since no biochemical markers are sufficient to diagnose the disease, which can only be characterized by imaging modalities like CT, MRI, and X-Ray.³ Nonetheless, clinical research suggests that markers of collagen degradation including urinary CTX-II, oligomeric matrix protein (COMP), and hyaluronic acid may be linked to disease severity, joint erosion, and can be useful biomarkers in monitoring osteoarthritis and rheumatoid arthritis.^4-7

Disc herniation is the result of the fibrocartilage between vertebrae becoming torn or punctured. When the disc is damaged, it may herniate and impinge upon nearby nerves, resulting in inflammation, neurological dysfunction, lower back and leg pain.²

Product description

References

Cartilage metabolism products

For in vitro diagnostic use.