Calcitriol Treatment Attenuates Inflammation and Oxidative Stress in Hemodialysis Patients with Secondary Hyperparathyroidism

Hemodialysis patients with secondary hyperparathyroidism (SHP) suffer from excessive oxidative stress and inflammation. Vitamin D analogues are currently the first line therapy for SHP, but the influence of vitamin D treatment on inflammation and oxidative stress remains unknown. This study investigated the influence of vitamin D therapy on oxidative stress and inflammatory markers in hemodialysis patients with SHP. Twenty-five patients (mean age 58 ± 12 years, 13 males and 12 females) were enrolled in the study to receive calcitriol treatment for 16 weeks. We evaluated changes in the serum biochemical parameters, inflammatory markers [C-reactive protein (CRP) and interleukin-6 (IL-6) levels], serum oxidative stress condition [total antioxidant status (TAS)], and CD4(+) T-lymphocyte intracellular cytokines [interferon γ (IFN-γ) and interleukin-4 (IL-4)] before and at the end of the 16-week calcitriol treatment. Correlations between each of these factors were also studied. All patients with SHP had low serum 1,25-dihydroxyvitamin D(3) levels and elevated serum levels of intact parathyroid hormone (iPTH), CRP and IL-6. Twenty patients (10 males and 10 females) responded to the calcitriol therapy, with significant decrements in serum iPTH. Our results showed that calcitriol can effectively suppress iPTH secretion, reduce inflammatory markers (CRP and IL-6) and oxidative stress. It can also effectively reduce inflammatory cytokine (CD4(+) IFN-γ) and increase anti-inflammatory cytokine (CD4(+) IL-4). Interestingly, significant correlations between CD4(+) IFN-γ levels and serum iPTH levels, as well as between TAS and iPTH levels were noted. Overall, our study has demonstrated calcitriol treatment significantly attenuates inflammation and oxidative stress in hemodialysis patients with SHP.