Vitamin D supplementation reduces systemic modulation of oxidative stress and collagen degradation in keratoconus patients

Abstract

Aims/Purpose: To assess whether vitamin D (Vit D) supplementation modulates systemic biomarkers involved in collagen degradation and oxidative stress in adolescent patients affected with keratoconus (KC).Methods: This study included forty adolescent patients (age range: 16–19 years) with KC and Vit D insufficiency (<30 ng/mL). The patients were supplemented with vitamin D for 6 months and followed up for additional 6 months (total study duration: 12 months). Blood samples were collected at 1, 6, and 12 months. The levels of Vit D or its receptor (VDR), collagen catabolism (type I collagen degradation product; ICTP), and oxidative stress (Peroxisome proliferator‐activated receptor gamma; PPAR‐γ) were quantified by ELISA or RT‐PCR.Results: We found that Vit D levels significantly increased at 6 months after supplementation. Moreover, at month 6 the expression of VDR was upregulated (p < 0.01), while collagen degradation (ICTP; p < 0.01) and oxidative stress (PPAR‐γ; p < 0.05) were significantly reduced.Conclusions: Our findings show that Vit D supplementation reduces oxidative stress and collagen catabolism, which have a key role in KC pathophysiology. These findings provide a potential mechanism by which Vit D could impact KC progression and provide preliminary evidence that KC may be a systemic disease.