Vitamin D: Molecular Biology and Gene Regulation

The essential role of vitamin D in calcium and phosphate homeostases often overshadows its more subtle, but critical, functions in other physiologic systems. Many of these nonclassical actions are disrupted in chronic kidney disease and contribute to morbidity and mortality, as evidenced by the increased survival in patients receiving active vitamin D therapy. Calcitriol and its analogs can activate and repress genes that control progression of renal disease, vascular calcification, and secondary hyperparathyroidism, with overall beneficial effects on outcomes. It is also important to consider that many of the target cells for vitamin D are capable of producing their own calcitriol and under controlled conditions in response to natural cues. Thus, the often-poor vitamin D status of chronic kidney disease patients should be corrected to allow these systems to function properly. Continued basic and clinical research on the integrated network of vitamin D actions should allow the development of improved strategies to enhance the survival of chronic kidney disease patients.