[Studies on the pathogenesis and pathophysiology of renal osteodystrophy. II. Bone histology of chronic renal failure patients at the time of starting hemodialysis].

We studied the relationship between the histomorphometric parameters of bone structure in biopsied iliac crest bone specimens and the serum biochemical parameters in 62 chronic renal failure (CRF) patients at the time of starting hemodialysis. These patients were classified into 4 groups according to Coburn's definition: 4 patients with osteomalacia, 1 with osteitis fibrosa, and 57 with mild type. Serum corrected Ca levels were significantly lower in cases with osteomalacia than those of mild type, which suggested that hypocalcemia was related to Calcification disturbance in end-stage renal failure. The bone histomorphometry revealed that in CRF patients, osteoid and bone resorption parameters were significantly higher and calcification parameters were significantly lower than those of normal controls. Osteoclast and osteoblast surfaces were significantly correlated with osteoid and bone formation parameters. In diabetic nephropathy patients, serum C-PTH levels were significantly lower than those of patients with non-diabetic nephropathies. Bone mass, osteoid and bone formation parameters were also significantly lower in diabetic nephropathy patients, which showed that low turnover bone mass decrement has already appeared at the time of starting hemodialysis. There was a significant negative correlation between serum corrected Ca levels and osteoid parameters. A significant relationship was also found between serum alkaline phosphatase levels and both osteoid and bone formation parameters. Serum C-PTH levels were significantly related to osteoid, bone resorption and bone formation parameters, demonstrating the presence of high turnover bone in secondary hyperparathyroidism. This study clarifies that morphological changes of bone structure are present at the time of starting hemodialysis in CRF patients.