Collagen is the most common protein found in the human body. It is found in almost all organs and body parts, though often in different types. In general, collagen winds itself into a fiber mesh that adds structural stability to that specific body part. It is commonly associated with skin integrity, but is critical for proper function of many other body parts, too.
Collagen fibers and networks add structural strength to many body parts. It is abundant in skin, where it makes up about 80 percent of the dry skin weight in a normal person. Due to its capability to interact with itself and with other proteins, such as elastin, it helps support skin and give it its elastic nature. Slight changes in the types of collagen in other body parts cause it to add greater strength, such as in bone, or finer networks of fibers, such as in blood vessels.
At least 12 types of collagen exist, four of which are commonly found in different body parts. Type I collagen is the most abundant type and is found in skin, bone and other connective tissues. Type II is commonly found in cartilage and Type III collagen is used during wound repair. Type IV is found in membranes of blood vessels and helps to filter blood components.
The strength in collagen comes from its unique protein structure. Its amino acid sequence allows it to form tightly winding fibers that can interact with each other, as well as other proteins. The amino acids require some modification by enzymes in your body before they are used in collagen, including enzymes that depend on vitamin C.
Many diseases result from mutations in different collagen genes. They are generally characterized by loss of strength in specific body parts. For example, a mutation in the type of collagen found in bone can lead to osteogenesis imperfecta, a condition in which bones break much more easily than normal. Additionally, due to the necessity of vitamin C during collagen creation, poor nutrition can lead to collagen disorders as well. Scurvy, for example, results from the loss in strength of skin and bone collagen, resulting in loss of teeth and decay of skin integrity.
Collagen is sensitive to both environmental and natural processes. It can be damaged by too much exposure to ultraviolet light, and can also begin to degrade naturally over time. For these reasons, much research has been focused on increasing natural production of collagen and on collagen replacement. Advances in these ares will also represent potential treatments to help patients who suffer from collagen disorders.