Effect of weight reduction on leptin, total ghrelin and obestatin concentrations in prepubertal children.

The aim of the study was to evaluate fasting levels of glucose, insulin, leptin, total ghrelin, and obestatin in a group of prepubescent obese children before and after weight loss. We enrolled 64 prepubescent obese children, but only 35 completed the study (mean age 7.6 +- 0.9 years, 19 females) and 20 normal-weight prepubescent children as controls. Fasting plasma concentration of glucose, insulin, Homeostasis Model assessment for insulin resistance (HOMA-IR), and leptin, total ghrelin, and obestatin levels were measured at baseline and after a 6-month lifestyle intervention (i.e. improved nutrition and increased physical activity). At baseline, obese children showed significantly (p less than 0.001) higher leptin and obestatin levels, and lower total ghrelin concentrations than control subjects. Weight loss significantly (p less than 0.001) diminished plasma leptin and insulin levels and increased ghrelin and obestatin concentrations. Weight loss in prepubescent children is associated with a significant change in leptin, ghrelin and obestatin concentrations. These results confirm the hypothesis that levels of these hormones are closely associated with obesity in childhood and might take part, as consequence but not as a cause, in glucose, fat, and energy metabolism.

Inhibition of matrix metalloproteinases prevents the potentiation of nondeprived-eye responses after monocular deprivation in juvenile rats.

The ocular dominance (OD) shift induced by monocular deprivation (MD) during the critical period is mediated by an initial depression of deprived-eye responses followed by an increased responsiveness to the nondeprived eye. It is not fully clear to what extent these 2 events are correlated and which are their physiological and molecular mediators. The extracellular synaptic environment plays an important role in regulating visual cortical plasticity. Matrix metalloproteinases (MMPs) are a family of activity-dependent zinc-dependent extracellular endopeptidases mediating extracellular matrix remodeling. We investigated the effects of MMP inhibition on OD plasticity in juvenile monocularly deprived rats. By using electrophysiological recordings, we found that MMP inhibition selectively prevented the potentiation of neuronal responses to nondeprived-eye stimulation occurring after 7 days of MD and potentiation of deprived-eye responses occurring after eye reopening. Three days of MD only resulted in a depression of deprived-eye responses insensitive to MMP inhibition. MMP inhibition did not influence homeostatic plasticity tested in the monocular cortex but significantly prevented an increase in dendritic spine density present after 7 days MD in layer II-III pyramids.

Molecular analysis of the CART gene in overweight and obese Italian children using family-based association methods.

AIM: In our study, we evaluated if CART gene A1475G and DeltaA1457 polymorphisms could be associated with obesity. PATIENTS AND METHODS: We recruited 133 Italian trios from among 103 (50 males and 53 females) overweight children (mean age 10.5 years, range 6-14 years; mean BMI 26.1 +/- 3.2 kg/m(2)), and 30 (16 males and 14 females) obese children (mean age 9.0 years, range 6-11 years; mean BMI 32.3 +/- 2.0 kg/m(2)). We also selected 187 non-obese unrelated controls. RESULTS: The allele frequencies of the A1475G single nucleotide polymorphism (SNP) were significantly higher in overweight children (0.07) than in control children (0.02) (p = 0.03) and control adults (0.02) (p = 0.02). Moreover, the allele frequencies were significantly different between obese children (0.08) and control children (0.02) (p = 0.03), and between obese children (0.08) and control adults (0.02) (p = 0.02). The DeltaA1457 SNP showed no significant association with overweight/obesity. TDT statistic revealed a preferential transmission of the 1475G allele from heterozygous parents to overweight children (p < 0.01) and to obese children (p < 0.05). No statistically significant excess transmission of the DeltaA1457 allele was found. CONCLUSION: Our results supported the hypothesis that inherited variations of the CART gene could influence the development of obesity also in Italian children.