Impact of the reduction of insulin-like growth factor 1 induced by glucocorticoid therapy on bone metabolism in primary nephrotic syndrome patients / 中华肾脏病杂志

ABSTRACT

Objective To observe the change of insulin-like growth factor 1 (IGF-1)before and after glucocorticoid (GC) therapy and to explore the effect of its change on bone metabolism in primary nephrotic syndrome (PNS) patients.Methods A total of 39 PNS patients with mean age of (36.73±12.15) years received GC therapy were selected from January 2008 to August 2009 in our hospital.Serum IGF-1,albumin,calcium,phosphorus,parathormone (PTH),25hydroxy vitamin D3,bone gla protein (BGP),degradation products of C-terminal telopeptides of type I collagen (CTx),24-hour urinary protein excretion and the ratio of urinary calcium to creatinine were measured at five time points-before GC therapy,4 weeks,8 weeks,12 weeks and 24 weeks after the use of GC.BMD was also detected at the same time points.Correlations among indexes were analyzed by Pearson.Results Thirty-six PNS patients fulfilled the follow-up and had complete clinical data,while other 3 patients lost.After GC treatment,serum calcium and 25hydroxy vitamin D3 were significantly increased in a time-dependent manner and were negatively correlated with 24-hour urinary protein excretion (r=-0.749,r=-0.831,P＜0.05,respectively).Serum BGP and IGF-1 were decreased after GC therapy in a time-dependent manner while CTx was significantly increased until week 12 after treatment (P＜0.05).Compared with pre-treatment,BMD of various parts had no significant difference at week 4; BMD of lumbar spine (L1-L4) was significantly decreased until week 8 (P＜0.05); BMD of femoral neck and femoral shaft was significantly decreased at week 24 (P＜0.05).IGF-1 was positively correlated with BGP and BMD (r=0.896,r=0.495,P＜0.05) and negatively correlated with serum CTx (r=-0.697,P＜0.05 ).Conclusions Serum IGF-1 level decreases in a time-dependent manner after GC treatment,which is correlated to BGP,CTx and BMD.Glucocorticoid treatment affects bone metabolism through IGF1 pathway possably in patients with PNS.IGF-1 may be used as a new bone biochemical marker of glucocoritcoid - induced osteoporosis.