When proNGF binds to sortilin and p75, the cell death signal is transduced into the cell. This study examined how sortilin gene expression changes in cultured human epidermal cells depending on the glucose concentration in the culture medium. The results might help elucidate if sortilin in epidermal cells is involved in the delay of wound healing in diabetes. Materials and methods: Epidermal cells were grown in a serum-free, glucose-free culture medium for 24 hours. The new medium was prepared

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... ith a glucose concentration of 0, 20, 40, 60, 100, 200, 400, or 800 mg/dL. The cells were grown in each medium for an additional 24, 48, and 72 hours. At each culture time, the sortilin gene expression level at 100 mg/dL glucose was compared with the expression levels at other glucose concentrations. Results and discussion: When the cells were grown in the new medium for 24 hours, the sortilin gene expression level at 100 mg/dL glucose did not differ significantly from the expression levels at other glucose concentrations. At 48 hours of culture, only the sortilin gene expression level at 0 mg/dL glucose was significantly higher than the expression level at 100 mg/dL glucose (p=0.002). At 72 hours of culture, only the expression level at 0 mg/dL glucose was significantly higher than the expression level at 100 mg/dL glucose (p<0.001). The results suggest that the sortilin gene levels of epidermal cells are not clinically problematic at low glucose concentrations, just as at high glucose concentrations, provided the glucose levels are sufficient to maintain biological activities.