Detection of galectin-3 and localization of advanced glycation end products (AGE) in human chronic skin wounds

Abstract

The matricellular protein galectin-3 (Gal-3) is upregulated in excisional skin repair in rats where it has been shown to modulate the inflammatory phase of repair. Recent research into kidney pathology has implicated Gal-3 as a receptor for advanced glycation end products (AGE), resulting in the binding and clearance of these molecules. AGEs are thought to contribute to defective skin repair in diabetic patients as well as a result of the normal aging process. However, the distribution and localization of Gal-3 and AGEs has never been performed in human chronic skin wound tissue. Using immunohistochemistry, the localization of Gal-3 and AGEs in tissue isolated from chronic wounds and non-involved skin from the same patient was investigated. Of the 16 patients from which tissue was isolated, 13 had type II diabetes, one had type I diabetes and 2 patients without diabetes were also examined. In non-involved dermis, Gal-3 was detected strongly in the epidermis and in the vasculature. However, at the wound edge and in the wound bed, the level of Gal-3 labelling was greatly reduced in both the epidermis and vasculature. Labelling of serial sections for Gal-3 and AGE demonstrated that where Gal-3 immunoreactivity is reduced in the epidermis and vasculature, there is a concomitant increase in the level of AGE staining. Interestingly, similar labelling patterns were evident in diabetic and non-diabetic patients. The results from our study demonstrate an inverse correlation between Gal-3 and AGEs localization, suggesting that Gal-3 may protect against accumulation of AGEs in wound healing.