The study found that diabetic foot ulcers have high levels of some antimicrobial proteins (beta‑defensins) but very low or no levels of the peptide LL‑37, which helps fight infections and heal wounds. In lab tests, skin cells from these ulcers also made less LL‑37 when exposed to bacteria compared to healthy skin cells.

Foot ulcers are one of the main diabetes complications due to its high frequency and difficulty of complete healing. There are several factors that participate in diabetic ulcers development and limited information exists about the role of antimicrobial peptides (AMP) in its pathogenesis. The aim of this study was to analyze the expression pattern of the main AMPs: Human Neutrophil Peptide (HNP)-1, Human β-defensin (HBD)-1, HBD-2, HBD-3, HBD-4 and cathelicidin LL-37 in biopsies from diabetic foot ulcers (DFU). 20 biopsies from DFU grade 3 according to Wagner's classification and 20 biopsies from healthy donors were obtained. Real time PCR, immunohistochemistry and primary cell cultures were performed. β-Defensins were overexpressed in DFU, whereas LL-37 has low or none expression in comparison with healthy skin. When primary cell culture from these biopsies were performed and infected with Staphylococcus aureus, epidermal cell from diabetic ulcers showed lower LL-37 expression compared with cell cultures from healthy donors skin. These results suggest that though most AMPs are expressed in DFU, this production is not appropriate to promote wound healing and contain secondary infections.