Table 2.

Cell types, their respective functions in wound healing, and the effect of chitin or chitosan upon these functions.

Cell Type	Function in Wound Healing	Effects of Chitin or Chitosan
Red blood cells	Supportive role in fibrin clot formation.	Chitosan forms a coagulum with red blood cells.
Polymorphonuclear neutrophils (PMN)	Clean wound site of foreign particles and cell debris.	Chitin and chitosan attract PMNs to wound site.
Macrophages	Consume dead cells, attract fibroblasts, support skin and blood vessel replacement and synthesis of the extracellular matrix.	Chitin and chitosan attract macrophages. Chitosan stimulates cytokine production (TGF-β1, PDGF, IL-1).
Fibroblasts	Reformation of the dermis and synthesis of extracellular matrix.	Indirect effect through macrophage cytokines and stimulates IL-8 production.
Keratinocytes	Reformation of epidermis.	Indirect effect through macrophage cytokines.