Norikazu Toi, Masaaki Inaba, Eiji Ishimura, Naoko Tsugawa, Yasuo Imanishi, Masanori Emoto, Yoshiaki Hirayama, Shinya Nakatani, Akihiko Saito, Shinsuke Yamada
Serum 1,25(OH)2 D and 24,25(OH)2 D are decreased in CKD. Megalin in proximal tubular epithelial cells reabsorbs glomerular-filtered 25(OH)D-DBP complex to convert 25(OH)D to 1,25(OH)2 D and 24,25(OH)2 D. Urinary C-megalin excretion is increased via exocytosis from injured nephrons overloaded with megalin-mediated protein metabolism. This study investigated the significance of urinary C-megalin excretion in vitamin D metabolism in 153 pre-dialysis CKD patients. Urinary C-megalin was positively associated with urinary protein, β2 MG and α1 MG, and exhibited negative correlations with serum 25(OH)D, 1,25(OH)2 D and 24,25(OH)2 D...
February 18, 2019: Scientific Reports