Expression of matrix metalloproteinases, cytokines, and connexins in diabetic and nondiabetic human keratinocytes before and after transplantation into an ex vivo wound-healing model

OBJECTIVE - Wound healing is known to require a well-organized balance of numerous factors, e.g., cytokines, matrix metalloproteinases (MMPs), and their inhibitors, as well as direct cell-cell communication (connexins). Disruption of this balance may lead to the formation of chronic wounds such as diabetic foot ulcers. The transplantation of autologous keratinocytes is a promising therapy for diabetic foot ulcers however, little is known about their characteristics on a molecular level. Therefore we intended to characterize transplanted keratinocytes from diabetic and nondiabetic origin before and after transplantation. RESEARCH, DESIGN AND METHODS - We isolated human keratinocytes from diabetic and nondiabetic origins and transplanted them into an ex vivo wound healing model. To characterize the keratinocytes, we investigated mRNA expression of MMP-1, MMP-2, and MMP-9; tissue inhibitor of MMP (TIMP)-1 and TIMP-2; interleukin (IL)-1 beta, tumor necrosis factor (TNF)-alpha; Cx26 (connexin 26) and Cx43; and, for connexins, immunolocalization. RESULTS - We found no significantly increased expression of the molecules investigated in cultured keratinocytes from diabetic compared with nondiabetic origin, even though there were significant differences for MMP-2, IL-1 beta, and TNF-alpha in skin biopsies. Expression of IL-1 beta was significantly lower in keratinocytes from diabetic origin. In the course of wound healing, differences in the dynamics of expression of MMP-1, 1L-1 beta, and Cx43 were observed. CONCLUSION - Our results suggest that keratinocytes from diabetic origin are as capable for transplantation into chronic wounds as keratinocytes from healthy origin at the starting point of therapy. However, differences in expression dynamics later on might reflect the systemic influence of diabetes resulting in a memory of the transplanted keratinocytes.