Increased T-helper interferon-gamma-secreting cells in obese children.

OBJECTIVE: Leptin, an adipocyte-secreted hormone, has emerged as a potential candidate for the link between obesity and the proinflammatory state. Specifically, leptin modulates T-helper (Th) cells toward a Th1 phenotype, with the secretion of proinflammatory cytokines. The aim of this study was to evaluate the Th1/Th2 balance in obese children and its relation with hormonal and metabolic features. STUDY DESIGN: In 50 obese children and 20 control children, we measured the CD4-positive Th cells that secrete interferon (IFN)-gamma or interleukin (IL)-2 (taken as an index of Th1 cells), and IL-4 (taken as an index of Th2 cells) as well as serum glucose, insulin, insulin resistance (IR) index (as homeostasis model assessment model (HOMA)), lipid profile, aminotransferases, leptin and ghrelin. Obese children also underwent dual energy X-ray absorptiometry scan measurements, and liver ultrasound scanning. RESULTS: Geometric mean percentages of IL-2- and IL-4-CD4 secreting cells in obese children were not significantly different from those found in control children. However, the geometric mean percentage of CD4-positive T cells secreting IFN-gamma was significantly higher in the obese than in the control (P < 0.0001, t-test) group. Within the entire group of study children, the percentage of IFN-gamma-positive cells was positively associated with leptin (P = 0.002), insulin (P < 0.00 005), and HOMA-IR values (P < 0.00 005). However, when these associations were restricted to the group of obese subjects, insulin and HOMA-IR values, but not leptin, retained statistical significance. Yet, in the obese group, the percentage of IFN-gamma-positive cells was associated with nonalcoholic steatohepatitis (NASH) (P = 0.001), but not with body mass index-standard deviation score and total body fat mass. CONCLUSIONS: In obese children, a shift to Th1-cytokine profile dominated by the production of IFN-gamma is related to insulin resistance as well as to NASH independently of anthropometric features and other metabolic characteristics. The prevalent Th1 pattern of secreted cytokines may be regarded as a mechanism contributing to inflammation in obesity.

Long-term effects of Helicobacter pylori eradication on circulating ghrelin and leptin concentrations and body composition in prepubertal children.

BACKGROUND: Helicobacter pylori, and the chronic gastric inflammation that it causes, may compromise the function and survival of ghrelin-producing cells, resulting in a decrease of circulating ghrelin levels. This finding raises the possibility that the infection might affect growth in children by reducing the ghrelin production. AIMS: To determine baseline circulating levels of ghrelin and leptin in prepubertal children with and without H. pylori infection and to evaluate the long-term effects of H. pylori eradication on circulating levels of ghrelin and leptin as well as on body composition. PATIENTS: Thirty children with H. pylori-associated gastritis, 35 children with H. pylori-negative gastric mucosa, and 20 healthy controls were studied. RESULTS: At baseline, while leptin levels were significantly lower in H. pylori-positive patients, ghrelin concentrations did not differ among the three study groups. However, a significant inverse correlation between ghrelin concentrations and histological severity of gastritis was found. Eradication of the organism was associated with a progressive decrease in ghrelin concentrations over baseline at both 6- and 12-month follow-ups. SDS-body mass index (BMI), lean and fat mass, as well as leptin concentrations, significantly increased over baseline at both follow-ups. CONCLUSIONS: In prepubertal children, serum ghrelin concentrations are inversely related to the severity of H. pylori-associated gastritis. In these youngsters, long-term eradication of H. pylori infection is associated with a significant increase in BMI, lean and fat mass along with a significant decrease in circulating ghrelin levels and an increase in leptin levels.

Nonalcoholic fatty liver disease and carotid atherosclerosis in children.

Nonalcoholic fatty liver disease (NAFLD) is closely associated with several metabolic syndrome features, including obesity, dyslipidemia, insulin resistance, and increased cardiovascular risk. The present study was undertaken to assess whether NAFLD in children is associated with increased carotid artery intima-media thickness (IMT), a marker of early-generalized atherosclerosis. We analyzed carotid IMT along with serum triglycerides, total, low-density lipoprotein and high-density lipoprotein cholesterol, glucose, insulin, insulin resistance index (as homeostasis model assessment of insulin resistance), aminotransferases, leptin, and adiponectin in 29 obese children with NAFLD, 33 obese children without liver involvement, and 30 control children. The diagnosis and severity of NAFLD was based on ultrasound scan, after exclusion of infectious and metabolic disorders. Obese children with NAFLD had significantly increased carotid IMT [mean 0.58 (95% confidence intervals 0.54-0.62 mm)] than obese children without liver involvement [0.49 (0.46-0.52) mm; p = 0.001] and control children [0.40 (0.36-0.43) mm; p < 0.0005]. In a stepwise multiple regression model, after adjusting for age, gender, Tanner stage, and cardiovascular risk factors, the severity of fatty liver was significantly associated with maximum IMT (b = 0.08; p < 0.0005). Our results suggest that NAFLD is strongly associated with carotid atherosclerosis even in childhood.