Leptin levels and IgF-binding proteins in malnourished children: effect of weight gain.
OBJECTIVE
Although it is well known that leptin reflects body fat content in adults, the regulation of leptin levels during childhood malnutrition is poorly understood. Insulin-like growth factor I (IGF-I) and the IGF-binding proteins (IGFBPs) may play important roles in the regulation of body composition. We investigated the relation between leptin, IGF-I, and IGFBPs in children with protein-energy malnutrition (PEM; before and after recovering 10% of their initial body weights) in comparison with well-nourished children.


METHODS
Fifteen PEM and 16 healthy children were studied on admission and after 10% weight gains in the malnourished group. Leptin was measured with radioimmunoassay, IGF-I and IGFBPs were measured with immunoradiometric assay.


RESULTS
Patients with PEM had a significantly lower body mass index and percentage of body fat than did the control children. Before weight gain, leptin, IGF-I, and IGFBP-3 were significantly lower and IGFBP-1 was elevated in the malnourished group compared with the control group. Among PEM patients, after 10% weight gains, the levels of leptin, IGF-I, and IGFBP-3 were significantly higher and IGFBP-1 significantly lower compared with the control group. Leptin correlated significantly with IGF-I in the normal children (r(s) = 0.86, P < 0.005). On admission, no correlation was observed between leptin and IGF-I (r(s) = 0.08, P < 0.16) and between leptin and IGFBP-3 (r(s) = 0.02, P < 0.27) in the malnourished group, but those levels improved after 10% recovery of their body weights (r(s) = 0.47, P < 0.002 and r(s) = 0.42, P < 0.005, respectively). In the PEM group, IGF-I correlated significantly with IGFBP-3 when the children gained weight (before: r(s) = 0.006, P < 0.31; after: r(s) = 0.32, P < 0.01). Our study showed results similar to those of anorexia nervosa studies, but the normalization of study variables was obtained in considerable less time for the same weight gain.


CONCLUSIONS
The main finding of this study was that, after refeeding with only a 10% weight gain, the PEM children normalized their leptin, IGF-I, and IGFBP-3 levels. These results provide evidence that leptin can function as link between this hormonal response and improved nutrition status.
Palacio
Ana Cristina
AC
Molecular Biology Laboratory and Public Nutrition Unit, Nutrition and Food Technology Institute, Universidad de Chile, Santiago, Chile.
Pérez-Bravo
Francisco
F
Santos
José Luis
JL
Schlesinger
Liana
L
Monckeberg
Fernando
F
D001823:Body Composition; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000032:analysis / Q000097:blood; D018969:Insulin-Like Growth Factor Binding Proteins / Q000032:analysis / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D020738:Leptin / Q000032:analysis / Q000097:blood*; D008297:Male; D011502:Protein-Energy Malnutrition / Q000097:blood*; D011863:Radioimmunoassay; D015430:Weight Gain / Q000502:physiology*
D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D020738:Leptin; D007334:Insulin-Like Growth Factor I