| [ Summary ] |
Renal osteodystrophy (ROD) is categorized into high turnover bone and low turnover bone according to bone histology. High turnover bone disease consists of ostitis fibrosa which is accompanied by secondary hyperparathyroidism (2° HPT) and mixed type of ostitis fibrosa and osteomalacia. Osteomalacia and adynamic bone result from low turnover of bone. In contrast to the focal assessment of disease by bone histology, biochemical markers provide an integrated assessment of the activity of ROD, which has been assessed in terms of caicium metabolism, collagen turnover, and indices of the functional activity of bone cells themselves. The patients with adynamic bone disease have lower plasma parathyroid hormone (PTH) level when compared to those with normal or high bone turnover. Therefore hypoparathyroidism is considered to be one of the responsible factors. Torres, et al. reported that plasma intact PTH levels below 120pg/ml was highly predictive of low bone turnover, and that the plasma PTH level above 300pg/ml was always associated with histologic features of ostitis fibrosa. So they concluded that PTH levels of 120 to 300pg/ml were required to avoid low bone turnover and ostitis in hemodialysis patients. In our hemodialysis patients who had plasma intact PTH below 120pg/ml the plasma levels of bone-ALP, osteocalcin, TRAP, and PICP were significantly lower than those in the patients who had PTH between 120 and 300pg/ml. Plasma levels of biochemical markers in healthy subjects are not thought to be the optimal levels of those in hemodialysis patients, because the precise matabolism and excretion of biochemical markers is not fully understood. Further studies are need in order to clarify the optimal levels of biochemical markers in hemodialysis patients. |