Clinical significance of monitoring bone turnover markers changes before and after growth hormone treatment of prepubertal children with idiopathic short stature

Objective To detect the levels and study the clinical significance of serum procollagen type Ⅰ amino-terminal propeptide (PINP) and β-C-telopeptides of type Ⅰ collagen (β-CTX) as bone turnover markers in recombinant human growth hormone (rhGH) treatment of prepuberty idiopathic short stature (ISS) children. Methods Forty patients of ISS (18 boys and 22 girls) had been collected and treated with GH 0.15 IU/(kg·d) injection every night.Serum levels of PINP, β-CTX, insulin-like growth factor 1(IGF-1) and insulin-like growth factor binding protein 3(IGFBP3) were measured by electrochemiluminescence immunoassay in ISS before treatment and after 3, 6 months, and they were also measured in 50 healthy children of the healthy control group, and the height, weight, body mass index, height standard difference score (HtSDS), bone age and growth rate were recorded. Results (1)In ISS group, the serum level of PINP[(479.51±134.61) μg/L] was lower than that of the healthy control group[(651.31±212.41) μg/L], the level of β-CTX[(0.84±0.33) μg/L] was higher than that of the healthy control group[(0.50±0.15) μg/L]. The differences were statistically significant (t=2.276, -2.709, all P 0.05) of ISS.After 3 months of GH treatment, the serum levels of PINP[(736.15±156.59) μg/L] and β-CTX[(1.08±0.27) μg/L] were higher than those before treatment in 40 cases, and the difference was statistically significant (t=4.736, 2.497, all P 0.05). HtSDS (-2.51±0.54) showed no significant difference (t=1.609, P>0.05) compared with 3 months of treatment.(3)The serum level of PINP was positively correlated with IGF-1 and IGFBP3 (r=0.636, 0.673, all P 0.05). PINP and β-CTX had significant correlation with HtSDS (r=0.655, 0.782, all P<0.05). Conclusions The serum PINP and β-CTX as bone turnover markers in serum can be used as one of the early supplementary indicators to predict GH response of ISS. Key words: Idiopathic short stature; Growth hormone; Bone turnover marker; Procollagen type Ⅰ amino-terminal propeptides; β-C-telopeptides of type Ⅰ collagen