Direct Effect of Paricalcitol on Anemia in Chronic Kidney Disease

Current activated Vitamin D therapies are approved for treating secondary hyperparathyroidism in chronic kidney disease (CKD), and a large body of experimental data in animals confirms the effects of Vitamin D that extend beyond mineral metabolism. Several studies show that the benefits are greater with the newer vitamin D analog paricalcitol when compared with calcitriol. A large gap exists in our knowledge between epidemiological studies in human that demonstrate improved outcomes with vitamin D use and observations in preclinical studies demonstrating the pleiotropic effects of Vitamin D. To explore the provenance of epidemiological outcomes in CKD, we conducted a pilot randomized trial to determine whether the use of paricalcitol, compared to calcitriol, leads to improvement in anemia, a marker associated with worse outcomes in chronic kidney disease, and whether this effect not only reflects the hyperparathyroidism correction, but is also dependent on the direct effects of paricalcitol on erythroid progenitor cells.