Summary Report 1-18 Months

Project context and objectives

The number of individuals developing type 2 diabetes mellitus (T2DM) early in life is growing globally. This alarming increase is connected with the rising incidence of childhood obesity. Life-style interventions are not effective in many of these children and additional approaches including pharmacology-based are desperately needed. The project “Beta-cell function in Juvenile Diabetes and Obesity” (Beta-JUDO) aims at investigating the role of the insulin-producing beta-cell in development of obesity and T2DM in children. The hypothesis is that individuals with accentuated insulin responses are at risk of developing obesity and T2DM since high insulin levels favours storage rather than combustion of energy. Thus, high insulin levels would be an early phenomenon preceding obesity development. The hypothesis is addressed in a translational approach involving measuring insulin secretory responses in obese children and from isolated human islets of Langerhans. In Beta-JUDO, paediatric obesity clinics and academic centres with focus on beta-cell biology, brown adipocyte imaging, transcript and protein profiling, genetics, epidemiology and bioinformatics have formed a consortium with a large drug company and with small companies (SMEs) specialized on biomarker discovery and clinical trials.

The main aim of Beta-JUDO is to identify novel pharmacological approaches that reduce weight via modulation of insulin levels. The following questions are addressed:

  1. Are elevated insulin levels in young obese individuals a cause or consequence of the obese state?
  2. What genetic variants, obtained from analysis of the obese children, are associated with yperinsulinemia/insulin hypersecretion?
  3. Under what conditions do isolated islets of Langerhans hypersecrete insulin, and how do drugs used today in adult obesity and T2DM affect insulin secretion from the isolated islet?
  4. What islet cellular mechanisms are connected with insulin hypersecretion and how are these mechanisms affected by drugs modulating insulin hypersecretion?
  5. How does a drug, which modulates islet insulin hypersecretion and is used for adult obesity and T2DM, affect obesity in adolescents?

The following objectives, coupled to the questions above, were formulated:

  1. To characterise insulin secretion in obese children at the childhood obesity clinics by performing oral glucose tolerance tests (OGTTs) and determining levels of glucose, insulin and C-peptide.
  2. To perform genetic analyses on the obese children and associating secretory phenotypes with genotypes.
  3. Characterise insulin secretion from isolated palmitate-treated human islets in the absence and presence of substances used today in the treatment of adult obesity and/or T2DM.
  4. Analyse the islets from a systems biology approach using proteomic, transcriptomic and lipidomic data sets.
  5. Perform a randomized, two-arm, double-blinded, placebo-controlled interventional study with obese adolescents and matched controls with a drug found to affect islet insulin hypersecretion.

Work performed and main results

The main results obtained during the first 18 months period were:

1) Obese and normal weight children have continuously been enrolled and annually followed-up. OGTTs have been performed on 240 patients and 50 controls. Glucose clamps and frequently sampled OGTTs have started. Samples for measurements of free fatty acids have been obtained, and a sensitive method for determination of fatty acids has been developed. Free fatty acid levels in plasma samples from 22 patients and 11 controls have so far been measured. A protocol for MRI analysis has been implemented, and scans of 60 patients and 7 controls have been conducted. DNA samples have been collected from 2250 patient and 240 control children.

2) The aim to define the insulin hypersecreting phenotype has started. First genetic analysis identified genes potentially associated with insulin traits in obese children. In the obese children we found that accentuated insulin levels were more prevalent in the youngest children. When such children were followed longitudinally, we observed a decline in insulin levels. In some of them the decline was to such an extent that glucose levels could no longer be controlled and the children were diagnosed with T2DM. From insulin and C-peptide measurements the contribution of newly secreted insulin was calculated. Based on these calculations of insulin secretion the obese children were stratified. These insulin secretory sub-phenotypes will during the next project period be used in genetic studies..

3) Model of isolated human islets hypersecreting insulin has been established: isolated human islets of Langerhans were used to define mechanisms of insulin hypersecretion in vitro. When islets were cultured in the presence of palmitate for 2 days, glucose-stimulated insulin secretion (GSIS) was accentuated. In contrast, GSIS was lowered in islets cultured for 7 days. This pattern of enhanced GSIS at early time points followed by decline at later time points was reminiscent of the insulin levels/secretion observed in obese children developing T2DM. We hypothesize that the mechanisms responsible for these time-dependent changes in palmitate-exposed hyper- and hypo-secreting islets is of relevance to understanding events occurring in obese children developing T2DM.

4) The first compound normalizing insulin hypersecretion has been selected. Protocols for protein, lipid and transcript profiling of islets have been optimized. Islets exposed to compound normalizing insulin hypersecretion have been subjected to lipidomic and proteomic analyses, data sets curated and statistically analysed. Lipidomics and proteomics data have been bioinfomatically analysed. Second compound normalizing insulin hypersecretion has been identified.

5) A protocol for an interventional study with approximately 50 obese adolescents has been developed. Discussions regarding the proposed active substance, where the substance tested in the islet is considered, are on-going with representatives for ethical review boards and regulatory authorities. Additional compounds will be selected representing novel principles derived from the genotype-phenotype correlation in the obese children and tested for their ability to normalize insulin secretion from the palmitate-treated islets.

A management team was furthermore established with the aim to ensure progression of the project towards its planned objectives and contractual commitments. Dissemination, exploitation and publication strategies were formulated. Project logo and web-portal for communication and data sharing were created. Connections with other FP7-funded diabetes projects were established. Standard operating procedures (SOPs) for clinical and pre-clinical work, data collection and handling were formulated and harmonized between partners. QA/QC work was conducted. Ethical applications and approvals for the clinical and pre-clinical work were collected and scrutinized by an ethical reviewer.

Expected final results, impact and use

The project is expected to generate results about:

  • To what extent insulin hypersecretion is an early phenomenon in the development of childhood obesity.
  • How insulin levels during fasting and OGTT develop in childhood obesity and what specific characteristics are associated with insulin hypersecretion in particular with regard to circulating levels of free fatty acids and white and brown fat characteristics, i.e. visceral/subcutaneous adipose tissue, liver and pancreatic fat.
  • Genetic background to insulin hypersecretion in childhood obesity.
  • Cellular and molecular mechanisms underlying insulin hypersecretion from the pancreatic beta-cell, which will be delineated applying systems biology analysis on data sets generated by multiple omics approaches including transcriptomics, proteomics and lipidomics on human isolated islets.
  • How currently used drugs for the management of adult obesity and T2DM as well as novel principles derived from genetic studies within the project affect islet insulin hypersecretion and cellular and molecular mechanisms underlying insulin hypersecretion.

The project is expected to have impact and use on the following areas:

  • Definition of international standards. OGTT reference values will be generated for obese and normal weight boys and girls of different ages. From these values opportunities to developing standards for insulin secretion and insulin resistance for different age groups will be explored.
  • Pharmacological strategies for intervention in childhood obesity.
  • Basis for the development of new future drugs targeting childhood obesity.
  • Attenuating the rise in in childhood obesity and T2DM in Europe and worldwide.

Childhood obesity has reached levels never seen before. By reducing obesity rates, both major health benefits, and economic benefits can be achieved. This project will raise awareness and knowledge among citizens in Europe, in health care, industry and funding agencies. Scientific benefits will be based on the integrated efforts in elucidating the impact of insulin early in childhood obesity development and developing strategies for the prevention.