Possible link between changes in plasma 24,25-dihydroxyvitamin D and healing of bone resorption in dialysis osteodystrophy.
Histomorphometric studies of bone biopsies were performed on 12 hemodialyzed patients before and after six months of treatment with 25-(OH) and 1 alpha-(OH) vitamin D3. Patients could be classified into three groups according to bone resorption: Group I with normal bone resorption; Group II with elevated initial bone resorption unresponsive to vitamin D treatment; group III with elevated initial bone resorption sensitive to vitamin D treatment. None of the patients had histological signs of osteomalacia. In Group I, plasma concentrations of 24,25-(OH)2D and the ratio of 24,25-(OH)2D to 25-(OH) D remained in the normal range throughout the study; in Group II these parameters were subnormal initially and did not increase above normal except in one case; in Group III, plasma concentrations of 24,25-(OH)2D were high before or at the beginning of vitamin D administration and normal at the time of the second biopsy and wide variations were observed in the ratio of 24,25-(OH)2D to 25-(OH)D. No difference was found between these last two groups with regard to the cumulative dose of vitamin D derivatives administered or the changes in plasma PTH, CT, calcium and phosphate. These observations suggest a specific regulation of plasma 24,25-(OH)2D concentrations in hemodialyzed patients and a possible link (independent of circulating PTH, CT, or phosphate) between this regulation and healing of bone resorption. However, no correlation was found between plasma 24,25-(OH)2D and either one of the simultaneously measured biochemical or histological parameters.
D015650:24,25-Dihydroxyvitamin D 3; D000328:Adult; D001862:Bone Resorption; D012080:Chronic Kidney Disease-Mineral and Bone Disorder / Q000378:metabolism*; D004100:Dihydroxycholecalciferols / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D006435:Renal Dialysis
D004100:Dihydroxycholecalciferols; D010281:Parathyroid Hormone; D015650:24,25-Dihydroxyvitamin D 3