Natural fiber exoskeletons of insects and arthropods. In shells and exoskeletons, the chitin fibers contribute to their hierarchical structure. In nature, pure chitin (100% acetylation) does not exist. It instead exists as a copolymer with chitin's deacetylated derivative, chitosan. When the acetylized composition of the copolymer is over 50% acetylated it is chitin. This copolymer of chitin and chitosan is a random or block copolymer. Chitosan is a deacetylated derivative of chitin. When the acetylized composition of the copolymer is below 50% it is chitosan. Chitosan is a semicrystalline “polymer of β-(1-4)-2-amino-2-deoxy-D-glucose”. One difference between chitin and chitosan is that chitosan is
Stromal cell-derived factor 1 receptors, of which CXCR stands out, regulate multiple processes such as morphogenesis, angiogenesis, and immune responses and are considered potential targets for drug development. In the gastrointestinal tract system, the CXCL12-CXCR4 axis is under investigation as an anti-fibrotic therapy in the treatment for chronic pancreatitis. For instance, blocking CXCR4, the receptor for CXCL12, with Plerixafor (AMD-3100) increased the effectiveness of combretastatin in a mouse model of breast cancer, presumably by preventing macrophages from being recruited to tumours.[15][16] Stromal cell-derived factor 1 The stromal cell-derived factor 1 (SDF1), also known as C-X-C motif chemokine 12 (CXCL12), is a chemokine protein that