Abstract
In order to clarify the bone metabolism of renal osteodystrophy in long-term hemodialysis, the relationship between histomorphometric findings of biopsied iliac crest bone specimens and serum concentration of PTH, vitamin D metabolites, alkaline phosphatase, Ca, P and vitamin A was studied in 42 patients on chronic hemodialysis. (1) The serum level of C-terminal PTH was significantly correlated with the number of osteoclasts, osteoblastic activity and bone formation rate. In the patients, in whom the serum level of 1, 25(OH)2D3 was relatively low, osteoid volume depended on osteoblastic activity. Fibrous tissue was demonstrated in most of the patients showing more than 5 ng/ml of C-terminal PTH. It was significantly correlated with serum C-terminal PTH. (2) The serum level of N-terminal PTH did not reflect a long-time effect of PTH to bone. Serum C-terminal PTH seemed to be a more useful maker of bone histology than serum N-terminal PTH. (3) Serum 1, 25(OH)2D3 was correlated with bone formation rate. It was suggested that lack of 1, 25(OH)2D3 seemed to be one of the pathogenetic factors of osteomalacia in chronic renal failure. (4) Serum 24, 25(OH)2D3 was participated in activation of osteoclast and osteoblast. In patients with markedly low serum level of 24, 25(OH)2D3, coupling of resorption with formation seemed to become very weak, so that impaired calcification increased osteoid tissue. (5) Serum alkaline phosphatase was correlated with the osteoblastic activity. (6) The mineralization of bone matrix seemed to delayed in hypocalcemic patients. (7) Serum P had a tendency to increase in patients with increased resorption. (8) In patient with relatively low or normal serum level of C-terminal PTH, hypervitaminosis A stimulated the activity of osteoclast and osteoblast. In patient with markedly high level of vitamin A, the shifting from resorption to formation was disturbed, so that resorption surface increased subsequently.
