Research on kidney and mineral metabolism in Japan: past, present, and future.

Since the identification of the kidney was the main site for the synthesis of calcitriol (1α, 25-dihydroxycholecalciferol), research on chronic kidney disease (CKD)-associated mineral metabolism disorders and their management has made rapid progress. Various active analogues of calcitriol have clinically become available for treating secondary hyperparathyroidism (SHPT), which is a representative mineral metabolism abnormality in CKD patients. A calcimimetic compound cinacalcet hydrochloride has also been developed for the medical management of SHPT through a different mechanism involving the calcium-sensing receptor. The concept of CKD-mineral and bone disorder (CKD-MBD) was proposed in 2006 to provide a comprehensive understanding of a disorder related to mineral metabolism abnormalities of CKD, based on the fact that these abnormalities are closely associated with cardiovascular disease as well as bone disorders (renal osteodystrophy). There has been a recent surge in the development of phosphate binders for CKD-MBD, focused on an effort to improve mortality. In Japan, high-quality basic and clinical research on CKD-MBD has led to the development of novel therapeutic drugs, such as maxacalcitol, falecalcitriol, and bixalomer. New practice guidelines have been published and are widely adapted in clinical practice.