Differential expression of matrix metalloproteinases and tissue-derived inhibitors of metalloproteinase in fetal and adult skins

Matrix metalloproteinases and their tissue-derived inhibitors determine the architecture of the extracellular matrix. In early gestation, the amount and organization of extracellular matrix may be associated with scarless repair of fetal skin wounds. To elucidate the part of the mechanism(s) underlying the phenotypic transition from scarless to scar-forming healing observed during fetal gestation, the ontogeny of matrix metalloproteinase-2, -9, -14 and their tissue inhibitors was characterized in non-wounded fetal human skin with different gestational ages from 13 to 33 weeks and adult skin using reverse transcriptase-polymerase chain reaction, immunohistochemical staining and western blot protocols. We showed that the levels of gene expressions for matrix metalloproteinase-2, -9, -14 and their endogenous inhibitors were significantly more in late gestational and adult skins than that in early gestational skin. Similar results were noted in terms of protein contents of these enzymes and inhibitors in fetal and adult skins. We concluded that the endogenous matrix metalloproteinase-2, -9, -14 and their endogenous inhibitors might be involved in skin development and in maintenance of cutaneous structure and function. Lower protein contents of tissue-derived inhibitor-1, -2 in early gestational skin might provide a predominantly antiscarring signal while higher protein expression of these two inhibitors might be associated with scar-forming healing in late gestational and adult skins.