OBJECTIVETo observe serum osteoprotegerin (OPG) level in children with nephrotic syndrome (NS) and changes in serum OPG level after glucocorticoid therapy, with the aim of studying the role of OPG in the bone metabolism of children with NS.

METHODSForty-four children with idiopathic NS were randomly selected as the study group, including 24 newly diagnosed, untreated patients and 20 who had relapsed during the process of glucocorticoid reduction (cumulative dose of glucocorticoid 28327±5879 mg/m2). Twenty-three age- and sex-matched healthy children served as the control group. Serum osteoprotegerin (OPG) level was measured using ELISA. Serum N-terminal midfragment of osteocalcin (N-MID osteocalcin) was determined using electrochemical luminescence immunoassays (ECLIA).

RESULTSSerum levels of OPG (211±55 ng/L) and N-MID osteocalcin (46±14 ng/mL) in the untreated NS group were reduced compared with 470±57 ng/L (OPG) and 73±9 ng/ml (N-MID osteocalcin) in the control group (P<0.05). Serum levels of OPG (176±42 ng/L) and N-MID osteocalcin (29±10 ng/mL) in the NS relapsed group were lower than in the untreated NS and control groups (P<0.05).

CONCLUSIONSBone metabolism disorders are found in children with NS. High-doses of glucocorticoid therapy can aggravate these disorders. Serum OPG levels in children with NS may be affected by both the renal disease itself and steroid therapy, suggesting that OPG is expected to become a new biochemical indicator for predicting changes to the bone metabolism of children with NS.