Serum versus tissue levels of FoxO3a, zinc, and iron in patients with vitiligo: is oxidative stress a local process?

Background Vitiligo is a pigmentation disorder characterized by milky white patches. It is caused by destruction of melanocytes because of an uncertain etiology. Oxidative stress (OS) hypothesis is highly considered in vitiligo pathogenesis. Antioxidants, including the Forkhead box O (FoxO) proteins, iron, zinc, and others, were found to be impaired in patients with vitiligo. Objective To assess the role of OS in the pathogenesis of vitiligo and to decide whether is it a local dysfunction, systemic process, or both. Patients and methods A case–control study was conducted, in which serum and tissue levels of FoxO3a, zinc, and iron were estimated in 50 patients with vitiligo and 30 age-matched and sex-matched healthy volunteers. FoxO3 levels were measured using ELISA kits. Iron and zinc levels were measured using colorimetric methods. Results No significant difference was found between serum FoxO3a levels in patients and controls (P=0.427), whereas lesional FoxO3a was significantly lower than its level in the skin of controls (P<0.001). Zinc and iron levels were significantly lower in serum and tissue of patients with vitiligo than in controls (P<0.001 for each). Conclusion Both serum and tissue levels of antioxidants are probably involved in the pathogenesis of vitiligo. However, tissue OS may be affected more. Some antioxidants, such as, zinc, may be involved more than others.