Association of Vitamin D Supplementation with VDR and CAMP Expression and Ulcer Healing in Diabetic Foot Infection Involving Biofilm-Forming Bacteria: An Exploratory Prospective Cohort Study

Background/Objectives: Diabetic foot infections (DFIs) are a major cause of morbidity and lower-limb amputation. Vitamin D exerts immunomodulatory effects through vitamin D receptor (VDR), which regulates the cathelicidin antimicrobial peptide (CAMP) gene that encodes cathelicidin (LL-37). However, their association with DFIs remains poorly understood. This study investigated the association between vitamin D supplementation, the vitamin D–VDR–CAMP–LL-37 pathway, and ulcer healing in DFIs involving biofilm-forming bacteria.