Effect of dexamethasone on the IGFBP-1 regulation in premature infants during the first weeks of life

BACKGROUND Early glucosteroid treatment in preterm infants has a negative impact on physical growth and development. So far, data on dexamethasone effect on the GH/IGF axis and the clinical outcome are conflicting. OBJECTIVE Therefore, we studied the effect of dexamethasone treatment on parameters of somatic growth and on the secretion of insulin like growth factors (IGFs) and insulin like growth factors binding proteins (IGFBPs) in preterm infants. METHODS In 75 preterm infants somatic development was assessed at birth and after 3 months of corrected age. IGF-I/II and IGFBP-1-3 were measured at the same time. According to their treatment regime the infants were assigned to the dexamethasone treated or the non-treated group. RESULTS At 3 months the 13 infants with dexamethasone had a lower body weight, slightly lower body length and a lower head circumference. IGF-II (464.4 +/- 97.4 vs 638 +/- 201.4 mug/l, p = 0.001) and IGFBP-3 (1800 +/- 426 vs 2105 +/- 547 mug/l, p = 0.045) were significantly reduced under the influence of glucocorticoids, whereas IGFBP-1 was elevated (59.6 +/- 61.0 vs 21.1 +/- 21.7 mug/l, p = 0.002). The ratio IGFBP-3/(IGFBP-1 + 2) was reduced in the dexamethasone group (1.827 +/- 0.868 vs 3.098 +/- 1.898 mug/l, p = 0.016), implying a significant retardation in the somatic development. CONCLUSION Dexamethasone impairs IGF and IGFBP secretion and stimulates IGFBP-1, an inhibitor of IGF-I. These pathways might contribute to alterations of the GH/IGF axis, particularly the ratio IGFBP-3/(IGFBP-1 + 2).