Vitamin D Status Modulates the Regenerative Potential of Serum Exosomes: A Therapeutic Strategy for Wound Healing

Background: Vitamin D is a critical factor in immune regulation and epithelial regeneration. Vitamin D deficiency is commonly observed in diabetic patients and is associated with impaired wound healing. Circulating exosomes transport bioactive molecules and influence cellular behavior relevant to tissue repair. Aim: This study aimed to investigate the capacity of serum exosomes derived from individuals with/without diabetes and with different vitamin D statuses to enhance keratinocyte-mediated wound healing. Methods: Serum samples were collected from diabetic patients and healthy nondiabetic controls [22 participants in total: eight healthy volunteers and 14 patients with type 2 diabetes, of whom six were vitamin D-sufficient (>20 ng/mL) and eight were vitamin D-deficient (