Study design of the Trial to Reduce IDDM in the Genetically at Risk (TRIGR)

Environmental factors and primary prevention in type 1 diabetes

The incidence of type 1 diabetes has been increasing rapidly among children in most European countries overthe last decades. Despite of the known strong genetic component in the disease only environmental factors can explain such a rapid change. The increase in incidence has been most conspicuous in the youngest age group, which emphasizes the importance of infancy and early environmental exposures. Nutritional and infectious factors affecting the young child or even the mother during pregnancy have been implicated to be important in the pathogenesis. The identification of single factors has been extremely difficult as reflected by many controversial reports on their importance. This difficulty may also be due to the heterogeneity of the disease mechanisms. Multiple mechanisms in different pathways may ultimately be responsible for beta-cell destruction. In most cases the disease is probably caused by a complex interplay between multiple factors including distinct genetic polymorphisms and environmental effects. Exploration of these pathways is needed for the development of effective preventive measures. The implementation of primary prevention trials will ultimately prove the value of various concepts generated for the disease pathogenesis.

An update on preventive and regenerative therapies in diabetes mellitus

Type 1A (immune-mediated) and type 2 diabetes mellitus are two of the most common severe chronic illnesses, affecting over 230 million people worldwide with an estimated global prevalence of 5.1%. Although type 1 and type 2 diabetes differ greatly in modes of pathogenesis, these illnesses share a common pathology and consequences characterized by loss of functional beta-cell mass and subsequent dysregulation of carbohydrate and lipid metabolism. Since therapy for diabetes and the associated complications poses enormous public health and economic burdens, novel preventive and regenerative therapies have emerged in the past decade with the aim to preserve beta-cell mass and delay the onset of diabetes. The goal of this review is to provide a comprehensive overview of current efforts in the fight against diabetes, and attempts to document all strategies that have emerged in clinical studies within the past 25 years. First, strategies to identify individuals at risk, ranging from whole-genome scans to autoantibody screening, will be discussed. Second, novel approaches to prevent or delay the onset of disease will be covered. Particular focus is given on emerging strategies for individuals at risk for type 1 diabetes that target T-cell regulation and induction of tolerance, while new pharmaceutical concepts in combination with lifestyle interventions are discussed within the scope of type 2 diabetes prevention. Lastly, important efforts to halt disease progression with emphasis on beta-cell regeneration are presented.

The Environmental Determinants of Diabetes in the Young (TEDDY) Study

The etiology of type 1 diabetes (T1D) remains unknown, but a growing body of evidence points to infectious agents and/or components of early childhood diet. The National Institutes of Health has established the TEDDY Study consortium of six clinical centers in the United States and Europe and a data coordinating center to identify environmental factors predisposing to, or protective against, islet autoimmunity and T1D. From 2004-2009, TEDDY will screen more than 360,000 newborns from both the general population and families already affected by T1D to identify an estimated 17,804 children with high-risk HLA-DR,DQ genotypes. Of those, 7,801 (788 first-degree relatives and 7,013 newborns with no family history of T1D) will be enrolled in prospective follow-up beginning before the age of 4.5 months. As of May 2008, TEDDY has screened more than 250,000 newborns and enrolled nearly 5,000 infants--approximately 70% of the final cohort. Participants are seen every 3 months up to 4 years of age, with subsequent visits every 6 months until the subject is 15 years of age. Blood samples are collected at each visit for detection of candidate infectious agents and nutritional biomarkers; monthly stool samples are collected for infectious agents. These samples are saved in a central repository. Primary endpoints include (1) appearance of one or more islet autoantibodies (to insulin, GAD65 or IA-2) confirmed at two consecutive visits; (2) development of T1D. By age 15, an estimated 800 children will develop islet autoimmunity and 400 will progress to T1D; 67 and 27 children have already reached these endpoints.

Two single nucleotide polymorphisms identify the highest-risk diabetes HLA genotype: potential for rapid screening

OBJECTIVE

People with the HLA genotype DRB1*0301-DQA1*0501-DQB1*0201/DRB1*04-DQA1*0301-DQB1*0302 (DR3/4-DQ8) are at the highest risk of developing type 1 diabetes. We sought to find an inexpensive, rapid test to identify DR3/4-DQ8 subjects using two single nucleotide polymorphisms (SNPs).

RESEARCH DESIGN AND METHODS

SNPs rs2040410 and rs7454108 were associated with DR3-DQB1*0201 and DR4-DQB1*0302. We correlated these SNPs with HLA genotypes and with publicly available data on 5,019 subjects from the Type 1 Diabetes Genetic Consortium (T1DGC). Additionally, we analyzed these SNPs in samples from 143 HLA-typed children who participated in the Diabetes Autoimmunity Study of the Young (DAISY) using Taqman probes (rs7454108) and restriction digest analysis (rs2040410).

RESULTS

With a simple combinatorial rule, the SNPs of interest identified the presence or absence of the DR3/4-DQ8 genotype. A wide variety of genotypes were tested for both SNPs. In T1DGC samples, the two SNPs were 98.5% (1,173 of 1,191) sensitive and 99.7% (3,815 of 3,828) specific for DR3/4-DQ8. In the DAISY population, the test was 100% (69 of 69) sensitive and 100% (74 of 74) specific. Overall, the sensitivity and specificity for the test were 98.57 and 99.67%, respectively.

CONCLUSIONS

A two-SNP screening test can identify the highest risk heterozygous genotype for type 1 diabetes in a time- and cost-effective manner.

Leaking gut in type 1 diabetes

PURPOSE OF REVIEW

Several studies have indicated that children with type 1 diabetes show altered intestinal immune system and, in particular, increased small intestinal permeability. This review discusses the recent research linking the gut and type 1 diabetes, which may reveal novel pathogenic pathways and new possibilities for disease prevention.

RECENT FINDINGS

Recent studies indicate that not only patients with manifest type 1 diabetes show increased small intestinal permeability and high serum levels of zonulin, that is protein controlling epithelial tight junctions, but prediabetic, normoglycemic individuals with beta-cell autoimmunity show signs of leaking gut. Also studies in BioBreeding-rat model of autoimmune diabetes suggest that high permeability of the intestine precedes autoimmune diabetes. The enteropathy characterized by increased intestinal permeability and inflammation seems to be the basis for the development of beta-cell destruction, as for example zonulin agonist, which decreases the gut permeability, prevents the development of diabetes.

SUMMARY

The leaking gut syndrome with subclinical inflammation is associated with beta-cell autoimmunity and type 1 diabetes. Furthermore, treatment of the leakiness has been reported to modulate development of autoimmune diabetes in animal models suggesting that intestinal environment plays a key role in the destruction of insulin-producing beta-cells in the pancreas.

Prevention of type 1 diabetes: the time has come

Improved understanding of the pathogenesis of type 1 diabetes mellitus has completely changed our view of this disease in the past 25 years-from an acute, fulminant disease, to a chronic, autoimmune process. Information on genetic and serologic markers has increased our ability to identify individuals at risk. Prospectively gathered data indicate that, with a combination of immunologic and metabolic studies, children with a 6-year risk of disease higher than 90% can be identified due to an ongoing immune process. They differ from children with overt disease only in the time it will take for glucose levels to rise above a diagnostic threshold. Therapies to change the progression of beta-cell loss have been tested in patients with newly diagnosed type 1 diabetes. With improved predictive capabilities and agents that can have longer-lasting effects than those tested more than 10 years ago, new prevention studies are underway. These studies are large and costly but the risks posed by such interventions compare favorably with those of developing hyperglycemia and of future complications portended by the diagnosis of diabetes. In this Review we discuss risk-stratification techniques and how they are applied, other diagnostic criteria, and outcomes from diabetes-prevention trials.

An automated standardized system for managing adverse events in clinical research networks

Multi-site clinical protocols and clinical research networks require tools to manage and monitor adverse events (AEs). To be successful, these tools must be designed to comply with applicable regulatory requirements, reflect current data standards, international directives and advances in pharmacovigilance, and be convenient and adaptable to multiple needs. We describe an Adverse Event Data Management System (AEDAMS) that is used across multiple study designs in the various clinical research networks and multi-site studies for which we provide data and technological support. Investigators enter AE data using a standardized and structured web-based data collection form. The automated AEDAMS forwards the AE information to individuals in designated roles (investigators, sponsors, Data Safety and Monitoring Boards) and manages subsequent communications in real time, as the entire reporting, review and notification is done by automatically generated emails. The system was designed to adhere to timelines and data requirements in compliance with Good Clinical Practice (International Conference on Harmonisation E6) reporting standards and US federal regulations, and can be configured to support AE management for many types of study designs and adhere to various domestic or international reporting requirements. This tool allows AEs to be collected in a standard way by multiple distributed users, facilitates accurate and timely AE reporting and reviews, and allows the centralized management of AEs. Our design justification and experience with the system are described.