Calcitriol Treatment Increases Serum Levels of the Soluble Receptor of Advanced Glycation End Products in Hemodialysis Patients with Secondary Hyperparathyroidism

Abstract

Cardiovascular disease is common in the patients with end-stage renal disease, who often suffer from secondary hyperparathyroidism (SHP). Vitamin D is considered for the first-line therapy managing SHP in hemodialysis (HD) patients and has a beneficial effect in the chronic inflammation and development of cardiovascular disease. The soluble receptor for advanced glycation end products (sRAGE) may be protective by binding AGE in the pathogenesis of atherosclerotic vascular complications, whereas extracellular RAGE-binding protein (EN-RAGE) represents pro-inflammatory ligands for RAGE. We have hypothesized that vitamin D treatment may alter the levels of sRAGE and EN-RAGE in HD patients. Therefore, this prospective observational study was performed in 51 HD patients with SHP who had low serum 1,25 dihydroxyvitamin D-3 (1,25D) levels and elevated intact parathyroid hormone (PTH) levels. We evaluated the changes in the values of sRAGE, EN-RAGE, and other inflammatory marker, interleukin-6 (IL-6), before and at the end of the 8-week calcitriol treatment. After calcitriol treatment, the serum levels of 1,25D were increased, whereas the serum intact PTH levels were decreased. In addition, the sRAGE levels were increased, whereas those of IL-6 were decreased after calcitriol treatment. A positive correlation between 1,25D and sRAGE levels (r = 0.609, P < 0.001) and a negative correlation between sRAGE and EN-RAGE levels (r = -0.368, P = 0.020) were detected after calcitriol treatment. This study suggests that calcitriol treatment could play an anti-inflammatory role through the increasing sRAGE in HD patients with SHP.