34 Insulin-Like Growth Factor I Deficiency is Associated with Chronic Lung Disease of Prematurity.

Abstract

Objective: Insulin-like growth factor I (IGF-I) is necessary for normal growth and development in infants. Recent research suggested that IGF-I deficiency is associated with the development of oxygen-induced retinopathy of prematurity (1). We hypothesized that low IGF-I levels might be a risk factor for oxygen-induced pulmonary damage in preterm infants, which leads to chronic lung disease (CLD) of prematurity.Methods: We measured growth hormone (GH) secretory patterns and levels of IGF-I and IGF binding protein 3 (IGFBP-3) in 34 preterm infants (gestational age(GA): 25–32 weeks, weights 526-1985 grams) at risk to develop chronic lung disease. Measurements were performed in clinically stable infants, requiring respiratory support. Between the 4th and 12th day of life, 6 h (with hourly intervals) and 24 h (with 6 h intervals) blood samples were taken for the determination of GH. In addition, IGF-I and IGFBP-3 levels were measured in the first blood sample. Results were adjusted for GA and birth weight SD score (BWSDS).Results: No significant differences in GH concentration were found between the different time points studied either in the 6 h or 24 h profiles; GH concentration between infants who developed CLD vs no CLD was not different (mean GH respectively 77±11 vs 79±8 mg/l, p=0.86, adjusted p= 0.56). IGF-I levels were significantly lower in CLD vs no CLD infants even adjusted for GA and BWSDS (respectively 1.3±0.1 vs 1.9±0.2 nmol/l, p=0.02, adjusted p=0.04). IGFBP-3 levels were not different between both groups (CLD 0.60±0.04 mg/l vs no CLD 0.71±0.05 mg/l, p=0.11, adjusted p=0.94).Conclusion: Our results support the hypothesis that IGF-1 deficiency may increase the risk to develop CLD. Since GH levels do not differ between infants who develop CLD and those who do not, differences in IGF-I levels may be explained by a relative GH resistance. Alternatively, levels of IGF-I may be lower due to a decreased production in preterm infants. With respect to the relationship between IGF-I and the development of serious sequelae associated with prematurity (1) our findings are comparable with observations by others). We therefore suggest that IGF-I may play an important role in the development of chronic lung disease of prematurity.