Childhood Obesity, and its associated metabolic complications, is rapidly emerging as one of the greatest global challenges of the 21st century. This application builds on a long track record of interdisciplinary collaboration among investigators using state of the art insulin clamp, MRS/MRI and stable isotope methodologies for noninvasively assessing muscle glucose metabolism in children. The first cycle of this grant started in 1991, investigating the correlates of Insulin Resistance, the most common metabolic complication of childhood obesity. Using epidemiological and physiological approaches we found that insulin resistance in obese children and adolescents is the best predictor of cardiometabolic risk factors and glucose intolerance and is associated with biomarkers of inflammation. These studies revealed a critical link between insulin resistance and altered tissue lipid partitioning in obese adolescents. The overall and continuing goal of the studies proposed in this competing renewal grant are to elucidate the putative mechanisms of insulin resistance in obese adolescents and to address a novel hypothesis regarding the potential role of Mitochondrial Dysfunction and Impaired Adipogenesis in its pathogenesis.
The specific aims are: 1) to assess whether decreased mitochondrial function, using 31P Magnetic Resonance Spectroscopy (MRS), may contribute to the increased intramyocellular (IMCL) lipid content in obese adolescents;2) to determine whether the obese phenotype characterized by high proportion of visceral fat and a low abdominal superficial layer is associated with an increased proportion of small adipose cells and reduced expression of genes regulating adipocyte proliferation and;3) to determine prospectively whether the obese adolescents with a high proportion of visceral and low subcutaneous fat depots will develop a worsening of glucose tolerance. These hypotheses-driven patient oriented research studies will be performed by a multidisciplinary team of investigators from several departments: Internal Medicine: (Dr Gerald Shulman), Diagnostic Radiology (Drs Constable and Rothman), NIDDK (Dr Sam Cushman), using an integrated team approach.

Public Health Relevance

Childhood Obesity is becoming the most common nutritional disorder worldwide. About 110 million children worldwide are now classified as overweight or obese, particularly African American and Hispanic Youths. Insulin Resistance, the insensitivity of peripheral tissues (e.g. muscle, liver and adipose tissue) to the effects of insulin, is the best predictor of whether the obese child will develop type 2 diabetes. Our previous studies using Magnetic Resonance Spectroscopy (MRS) and imaging (MRI) have clearly established the link between the fat content in the muscle of obese adolescents and insulin resistance. The present studies will focus on determining what might cause fat to accumulate in the muscle and deep abdominal cavity.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD028016-19
Application #
8458135
Study Section
Clinical and Integrative Diabetes and Obesity Study Section (CIDO)
Program Officer
Grave, Gilman D
Project Start
1991-06-01
Project End
2014-04-30
Budget Start
2013-05-01
Budget End
2014-04-30
Support Year
19
Fiscal Year
2013
Total Cost
$247,787
Indirect Cost
$98,067
Name
Yale University
Department
Pediatrics
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
Kursawe, Romy; Dixit, Vishwa D; Scherer, Philipp E et al. (2016) A Role of the Inflammasome in the Low Storage Capacity of the Abdominal Subcutaneous Adipose Tissue in Obese Adolescents. Diabetes 65:610-8
Hershkop, Karen; Besor, Omri; Santoro, Nicola et al. (2016) Adipose Insulin Resistance in Obese Adolescents Across the Spectrum of Glucose Tolerance. J Clin Endocrinol Metab 101:2423-31
Goffredo, Martina; Caprio, Sonia; Feldstein, Ariel E et al. (2016) Role of TM6SF2 rs58542926 in the pathogenesis of nonalcoholic pediatric fatty liver disease: A multiethnic study. Hepatology 63:117-25
Santoro, Nicola; Caprio, Sonia; Pierpont, Bridget et al. (2015) Hepatic De Novo Lipogenesis in Obese Youth Is Modulated by a Common Variant in the GCKR Gene. J Clin Endocrinol Metab 100:E1125-32
Zheng, Chao; Dalla Man, Chiara; Cobelli, Claudio et al. (2015) A common variant in the MTNR1b gene is associated with increased risk of impaired fasting glucose (IFG) in youth with obesity. Obesity (Silver Spring) 23:1022-9
Van Name, Michelle; Giannini, Cosimo; Santoro, Nicola et al. (2015) Blunted suppression of acyl-ghrelin in response to fructose ingestion in obese adolescents: the role of insulin resistance. Obesity (Silver Spring) 23:653-61
Perry, Rachel J; Camporez, João-Paulo G; Kursawe, Romy et al. (2015) Hepatic acetyl CoA links adipose tissue inflammation to hepatic insulin resistance and type 2 diabetes. Cell 160:745-58
Weiss, Ram; Magge, Sheela N; Santoro, Nicola et al. (2015) Glucose effectiveness in obese children: relation to degree of obesity and dysglycemia. Diabetes Care 38:689-95
Holder, Tara; Giannini, Cosimo; Santoro, Nicola et al. (2014) A low disposition index in adolescent offspring of mothers with gestational diabetes: a risk marker for the development of impaired glucose tolerance in youth. Diabetologia 57:2413-20
Santoro, Nicola; Caprio, Sonia; Giannini, Cosimo et al. (2014) Oxidized fatty acids: A potential pathogenic link between fatty liver and type 2 diabetes in obese adolescents? Antioxid Redox Signal 20:383-9

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