早产儿骨转化及早期补钙对骨转化的影响

目的 :动态观测早产儿骨转化生化标志物血骨钙素 (OC)、碱性磷酸酶 (AKP)、 型胶原羧基端肽(ICTP)的变化及早期补钙对它们及血钙 (Ca)、尿 Ca、血磷 (P)、尿 P的影响。方法 :对 4 0例早产儿分补钙组 (2 0例 ,出生早期给予 10 %葡萄糖酸钙 4 ml/ kg.d-1静脉输注 )与对照组 (2 0例 ) ,在出生 2 4 h及 11日龄 ,分别用 EL ISA法、放射免疫法及全自动生化分析仪测定血清 OC、ICTP、Ca、P、AKP浓度和尿 Ca、P及肌酐值。同时以 2 2例正常足月儿和早产儿对照。结果 :出生 2 4 h,早产儿血 AKP、ICTP分别为 (2 14 .35± 6 7.0 6 ) IU、(6 2 .88± 4 .0 7)μg/ L高于足月儿 [(14 7.86± 4 4.87) IU、(5 7.36± 6 .34)μg/ L ,P<0 .0 1];ICTP与胎龄及出生体重呈负相关 (r=- 0 .5 2 8、- 0 .6 14 ,P<0 .0 1) ;OC为 (6 48.77± 2 38.89) nmol/ L低于足月儿 [(85 1.6 8± 2 38.6 9) nmol/ L ,P<0 .0 1],而且与胎龄、出生体重呈正相关 (r=0 .35 9、0 .376 ,P<0 .0 5、<0 .0 1)。出生 11日龄 ,早产儿对照组 OC为 (94 7.2 5± 335 .4 7)nmol/ L,高达足月儿 [(94 1.6 5± 2 97.2 8) nmol/ L],而 ICTP[(6 5 .4 4± 6 .2 4 ) μg/ L]始终高于足月儿 [(5 7.10± 3.4 8)μg/ L];补钙组 OC及 ICTP分别为 (84 4.5 9± 2 6 7.2 4 )

Bone turnover and early parenteral calcium supply in preterm infants

OBJECTIVE: To explore the dynamic change in biochemical markers of bone turnover in preterm infants and the effect of early parenteral calcium supply. METHODS: Forty preterm infants were divided into parenteral calcium supply group and control group. Blood and urine samples were collected at 24 h and 11 d after birth. Serum osteocalcin (OC) was measured with ELISA, serum carboxyterminal telopeptide type I collagen (ICTP) with radioimmunoassay, serum alkaline phosphatase (AKP), calcium, phosphate, and urine calcium, phosphate, creatinine with automatic biochemical analyzer. Blood samples were also collected from 22 term infants as control. Calcium gluconate (10%, 4 ml/kg x d(-1)) was administered intravenously in parenteral calcium supply group. RESULT: At 24 h, serum AKP, ICTP [(147.86+/- 44.87)IU, (57.36+/- 6.34)micro g/L] in preterm infants were significantly higher than those [(147.86+/- 44.87)IU, (57.36+/- 6.34)micro g/L] in term infants, and negatively correlated with gestational age and birth weight (r =-0.528, P<0.01; -0.614, P< 0.01), but serum OC [(648.77+/- 238.89) nmol/L] in preterm infants was lower than that [(851.68+/- 238.69)nmol/L] of term infants, and positively correlated with gestational age and birth weight (r=0.359, P< 0.05; 0.376, P< 0.01). At 11 day, serum OC [947.25+/- 335.47)nmol/L] in preterm infants was markedly elevated and reached the level of term infants [(941.65+/- 297.28)nmol/L], but serum ICTP [(65.44+/- 6.24)micro g/L] in preterm infants was higher than that [(57.10+/- 3.48)micro g/L] in term infants all along. Serum AKP [(246.00+/-66.64)IU] in parenteral calcium supply group was higher than that [(206.53+/- 53.9)IU] in the control group. There were no significantly differences in serum OC and ICTP between parenteral calcium supply group and the control group. Calcium in serum and urine was elevated, phosphate in serum and urine was reduced in the parenteral calcium supply group. Urine analysis and kidney ultrasounds were normal. CONCLUSION: There is active bone formation and bone resorption in preterms as compared with terms. Alone parenteral calcium supply during early life can not increase formation of bone protein or decrease degradation of bone collagen, but can elevate serum calcium and urine calcium levels. Hematuria and renal calcification were not found in short duration.