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.