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).

Associations between ghrelin levels in serum of preterm infants and enteral nutritional state during the first 6 months after birth.

BACKGROUND: Previous studies have suggested a possible influence of ghrelin on foetal growth. After birth, the regulation of this newly discovered orexigenic peptide is largely unknown. OBJECTIVE: To study the relationship between circulating levels of ghrelin and enteral nutritional state in preterm infants during the first months of life. METHODS: Ghrelin levels were measured in a cross-sectional study by radioimmunoassay on the second day after birth (n = 51), at 3 months (n = 63) and at 6 months (n = 53) of corrected postnatal age. Complete data sets of auxological parameters, biochemical values, perinatal diseases, nutritional management and therapy were determined. RESULTS: All infants showed levels of ghrelin in postnatal serum. In correlation analyses and multivariable linear regression models, ghrelin was strongly related to enteral caloric intake on the second day after birth (all P < 0.01). At 6 months of corrected postnatal age, infants who were exclusively breastfed/formula fed had significantly lower ghrelin levels than infants with solid foods (Mann-Whitney U-test: P = 0.027). CONCLUSION: Ghrelin levels were positively correlated with the enteral nutritional state in preterm infants on the second day after birth. The introduction of solid foods increased the ghrelin levels in a group of preterm infants at 6 months of corrected postnatal age.

Associations of the IGF/IGFBP axis and respiratory diseases in neonatal patients during the first 6 months of life.

OBJECTIVES: To analyse IGFs in respect to somatic growth and neonatal diseases during the first 6 months of life. METHODS: IGF-I, IGF-II and IGF binding proteins (IGFBP-1, -2, -3) were determined by immunoassays in neonatal patients after birth (n = 67) and at 3 (3 mo; n = 75) and 6 months (6 mo; n = 47) of corrected postnatal age. Data on growth were tested for associations to the gestational age, birth weight (bw) SDS (/-2 SDS), neonatal morbidity and therapeutic strategies. RESULTS: All IGFs and IGFBPs changed significantly between birth and 3 mo of corrected age (p < 0.05). Perinatal respiratory diseases influenced IGF-II at 3 mo, and bronchopulmonary dysplasia IGF-II at 3 and 6 mo (all p < 0.05). IGF-I differed between the subgroups bw /-2 SDS (p < 0.05). At 3 mo, IGFBP-1 was significantly increased in infants with glucocorticoid administration during the first four weeks of life. CONCLUSION: The first months of life are characterised by a pole reversal of the somatotropic axis: IGFBP-1 and -2 decrease and IGFBP-3 increases. Respiratory diseases with an origin in the neonatal period, glucocorticoid therapy and low birth weight have an impact on the IGF pattern up to 6 mo. Prospective studies are necessary to investigate, whether the described link between the IGF/IGFBP axis and respiratory morbidity in neonatal patients has an impact on development in later infancy.

Does insulin-like growth factor 1 contribute in red blood cell transfusions to the pathogenesis of retinopathy of prematurity during retinal neovascularization?

BACKGROUND: Red blood cell (RBC) transfusions are associated with the development of retinopathy of prematurity (ROP). During the period of retinal neovascularization a rise of insulin-like growth factor 1 (IGF-1) may trigger rapid growth of new blood vessels. OBJECTIVES: To study endocrine factors in RBC transfusions that might be of importance for ROP. METHODS: IGF-1, IGF-2 and their binding proteins 1-3 (IGFBP-1-3) were determined by radioimmunoassays in 7 very-low-birthweight (VLBW) infants with ROP >or= stage 2 receiving a RBC transfusion, in 10 controls (VLBW infants with ROP