Maryam Sharifi Sistani - School of Advance Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Nima Behshtizadeh - School of Advance Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Maryam Bahreini - Sina Specialized & Subspeciality, Tehran University of Medical Sciences, Tehran, Iran.

IntroductionIt has demonstrated that the expression of Indoleamine2,3-Dioxygenase (IDO), metabolizes tryptophan into kynurenine. This reaction leads to prevent the immune rejection of semi-allogeneicfetus during pregnancy. By the expression of IDO in fibroblasts, tryptophan deficiencyresults in the apoptosis of Immune cells but not skin cells. As far as T cells are the reason for graft rejection, there is a new trend to experiment IDO-expressing xenogeneic fibroblasts in an animal model. The result isdecreasing CD3þ T lymphocytes after the expression of IDO fibroblasts, accelerating the wound healing process by neovasacplarization.IDO also induces angiogenesis by reducing tryptophan.MethodsAlthoughskin cells may beresistant to IDO expression unlike immune cells, the question is which types of primary skin cells are more resistant to kynurenine If we co-culture human T cells with IDO expressing fibroblasts in the presence of both skin fibroblasts and keratinocytes, both kinds of skin cells exceptT cells would beresistant to the lack of tryptophan by caspase 3 induction. Additionally, CHOP expressionis a repressor of GCN2 kinase path.For prolonging the viability ofskin grafts to experiment IDOand suppressing the proliferation of peripheral blood mononuclear cells, they can be co-cultured with IDO expressing fibroblasts of an allogeneic skin substitute in vitro. The following steps are considered: IDO expressing fibroblasts populated within collagen gelto induce the expression of IDO mRNA; then, it is treated with a thermo sensitive polymer which also has been treated with IFN gamma. In comparison with untreated IFN gamma, the results showed that the IDO mRNA expression and subsequently the suppression of peripheral blood mononuclear cell proliferation would be higher.DiscussionTemperature sensitive polymer could be an efficientalternative to maintainskin grafts. As IDO function locally affects the immune system and helps to prolong skin graft viability, it may be a surge in support forskin substitutes

Tissue engineering, Polymer, Indoleamine2,3-Dioxygenase, Immune suppressive, Skin grafts