Cross-linking effect collagen

Lee, C. R., Grodzinsky, A. J., and Pector, M. (2001). The effects of cross-linking of collagen-glycosaminoglycan scaffolds on compressive stiffness, chondrocyte-mediated contraction, proliferation and biosynthesis. Biomaterials 22,3145-3154. 

Figure 3.4 Factors affecting foreign body reaction and potential points of intervention at the level of the myofibroblast (1) inhibit synthesis or release of TGF-P (2) block stimulation by TGF-P of its membrane receptors on the activated fibroblast (3) inhibit the Smad proteins, which transfer the TGF-P effect to the nucleus (4) inhibit transcription of procollagen mRNA (5) inhibit translation of the message to form procollagen (6) inhibit prolyl-4-hydroxylase, which creates hydroxyproline and facilitates helix formation (7) inhibit lysyl oxidase, which cross-links the collagen (8) enhance the function of MMPs, which degrade collagen, or inhibit TIMPs, which degrade MMPs.

In recent years a number of authors have reported the specific enzymatic cleavage of the cross-links in collagen (Barkin and Oneson, 1961 High-berger, 1961b Kiihn et al., 1961 Nishihara, 1962 Schmitt, 1963 Kiihn et al., 1963a Rubin et al., 1963 Hafter and Hermann, 1963). The enzymes used include pepsin, ficin, trypsin, and unpurified pancreas extracts of these pepsin is the most effective. As pepsin has no esterase or other nonproteolytic activity it appears that the cross-links include, even if they are not entirely, sections of peptide chains. 

The effect of copper deficiency is not fully understood. The element is required for lysil oxidase activity which is necessary for cross-linking of collagen. Its deficiency has heen associated with growth retardation and anemia. Also has in dialysis patients a correlation heen demonstrated between serum copper levels and superoxide dismutase activity. 

The elasticity and structural integrity of the vascular matrix is dependent on ascorbate as an essential cofactor for molecular cross-linking of collagen, hence, the connective tissue-related defects found in scurvy. Even moderate ascorbate depletion, short of scurvy, has been shown to result in increased tendency of the gingiva to bleed or become inflamed (Leggott et al., 1986). Evidence suggests that ascorbic acid has beneficial effects on the human cardiovascular system beyond collagen formation and the antioxidant protection of lipids and LDL mentioned previously. 

Marzec, E. and Pietrucha, K. (2008). The effect of different methods of cross-linking of collagen on its dielectric properties. Biophysical Chemistry 132, 89-96. 

Sajithlal, G.B., Chithra, P., and Chandrahasan, G. 1998. Effect of curcumin on the advanced glyca-tion and cross-linking of collagen in diabetic rats. BiochemFharmacol. 56 1607-1614. 

Artificial skin had been made from a bilayer fabricated from a cross-linked mixture of bovine hide, collagen, and chondroitin-B-sulfate derived from shark cartilage with a thin top layer of siloxane. The siloxane layer acts as a moisture- and oxygen-permeable support and to protect the lower layer from the outer world allowing skin formation to occur in conjunction with the lower layer. Poly(amino acid) films have also been used as an artificial skin. Research continues in search of a skin that can be effectively used to cover extensive wounds and for burn patients. 

White, M. J., Kohno, I., Rubin, A. I., Stenzel, . H., and Miyata, T. (1973). Collagen films Effect of cross-linking on physical and biological properties. Biomater. Med. Devices Artif. Organs 1, 703-715. 

Blanque R, Cottereaux C, Gardner CR (2001) Phasic production of urinary pyridinium crosslinks in mice the effect of ovariectomy. Calcif Tissue Int 68 102-108 Eyre DR (1995) The specificity of collagen cross-links as markers of bone and connective tissue degradation. Acta Orthop Scand Suppl 266 166-170... 

Acetylpenicillamine is a weaker chelating agent than penicillamine, has no effect on collagen cross-links, and is not effective in rheumatoid arthritis. It has been used in the treatment of mercury poisoning (1). 

---