Collagen

Collagen is the main component of connective tissue and the most abundant protein in the human body. It is mostly found in fibrous tissues such as tendons, ligaments and skin.

Types

 * Type I: skin, tendon, vasculature, organs, bone (main component of the organic part of bone)
 * Type II: cartilage (main collagenous component of cartilage)
 * Type III: reticulate (main component of reticular fibers), commonly found alongside type I.
 * Type IV: forms basal lamina, the epithelium-secreted layer of the basement membrane.
 * Type V: cell surfaces, hair, and placenta

Synthesis
Collagen is made up primarily of glycine and proline. Vitamin C is a co-factor of my of the chemical reactions involved in collagen production. Vitamin C deficiency can results in impaired collagen synthesis and scurvy.

As a supplement
When hydrolyzed, collagen is reduced to small peptides, which can be ingested in the form of dietary supplement or functional foods and beverages with the intent to aid joint and bone health and enhance skin health. These hydroxyproline-containing peptides are transported into the target tissues (e.g., skin, bones, and cartilage), where they act as building blocks for local cells and help boost the production of new collagen fibers.

Pathogens and collagen degradation
Some bacteria and viruses, such as Bartonella, Herpes simplex virus , and Epstein-Barr virus , secrete (or cause host cells to secrete) virulence factors including collagenase, an enzyme which break downs collagen, or other compounds that interfere with collagen production.

Bartonella
A case study of a patient with a presentation similar to hypermobile EDS and a chronic Bartonella infection found their acquired joint hypermobility resolved with treatment for Bartonella.