P-85 Is there a role for vitamin A on the regulation of IGF-I in children?

Abstract

IGF system and vitamin A (VA) are important regulators of human growth and a wide range of physiological processes. Growth hormone and nutritional status are the main regulators of IGF system; however the role of the micronutrients is still not clear. The objective was to verify the effect of VA supplementation on IGF-I levels in VA deficient children. Ninety-four healthy children aged 5.5–11 years with regular follow-up in a pediatric clinic and no clinic evidence of vitamin A deficiency (VAD) entered the study. In order to access VA status serum retinol were determined by HPLC at baseline (BR) and 30 days (R30) after VA supplementation (200 000 IU of trans-retinyl palmitate) by +S30DR test (serum 30-day dose-response test). +S30DR was considered positive when (R30 −BR)× 100/R30 was 20%. IGF-I was also measured in both samples, by IRMA. Children were further divided in VAD and non-VAD. They were considered VAD if BR 1.05mmol/L or +S30DR positive. The samples were paired and compared using a nonparametric paired test. According to BR and +S30DR 24.5% and 28.7% of the children were considered VAD, respectively. IGF-I levels increased significantly with VA supplementation in the VAD group, either considering BR levels criterion (P = 0.001) or +S30DR test criterion (P = 0.004) while no difference was observed between baseline IGF-I and day-30 IGF-I in the non-VAD group. Baseline IGF-I was lower in the VAD than in the non-VAD group either considering BR (median: 190 vs. 260 mg/L) or +S30DR (median: 190 vs. 260mg/L) as criterion to VAD. No difference was found regarding day-30 IGF-I levels between VAD and non-VAD children. Conclusion: IGF-I levels increase after VA supplementation in children with subclinical VAD, these results suggest a possible role for VA on IGF-I regulation and support the idea that some of VA actions can be mediated by IGF-I, including the VA-supported growth.