[Usefulness of osteocalcin and CrossLaps as markers of bone turnover in children with chronic renal failure]

Abstract

Bone disorders resulting from abnormalities in mineral are common in patients with predialytic stage of chronic renal failure (CRF). Disturbances associated with: phosphate excretions, vitamin D3 metabolism, hypocalcemia, increased parathyroid hormone (PTH) and acid-base disturbances lead to bone pathology know as renal osteodystrophy (RO). Estimation of tempo turnover make possible markers, of which concentration means oneself in urine and in serum. The aim of this study was to estimate the urinary carboxy-terminal telopeptide of type I collagen as a index of bone resorption and osteocalcin as a marker of bone formation in correlation with intact PTH (iPTH) in predialytic children. The study group consisted of 39 children aged 6-17 y. All children were divided into 2 groups: I--21 predialytic pts; II--18 healthy children. The I group was divided into 2 subgroups: Ia--pts with normal range of iPTH; Ib--pts with higher range of iPTH. All patients were tested: for serum concentrations of: calcium (Ca), inorganic phosphorus (P), iPTH, OST; and for urinary CrossLaps (corrected with urinary creatinine).

Results: In subgroup Ib revealed correlation between OST and iPTH (p < 0.05); and between CrossLaps and OST (p = 0.05).

Conclusions: The results of investigation on OST and CrossLaps as bone metabolism markers in predialytic children revealed that evaluating highly specific biochemical parameters of bone turnover is useful in assessing the clinical status of that metabolism. The knowledge of correlation between levels of bone turnover markers and clinical status of a child might help in taking appropriate therapeutic decision and in preventing renal osteodystrophy.