Type 1 Diabetes as a Model for Prediction and Diagnosis

Diabetes in Danish bank voles (M. glareolus): survivorship, influence on weight, and evaluation of polydipsia as a screening tool for hyperglycaemia

Background

Previous studies have concluded that the development of polydipsia (PD, a daily water intake ≥21 ml) among captive Danish bank voles, is associated with the development of a type 1 diabetes (T1D), based on findings of hyperglycaemia, glucosuria, ketonuria/-emia, lipemia, destroyed beta cells, and presence of autoantibodies against GAD65, IA-2, and insulin.

Aim and Methods

We retrospectively analysed data from two separate colonies of Danish bank voles in order to 1) estimate survivorship after onset of PD, 2) evaluate whether the weight of PD voles differed from non-PD voles, and, 3), evaluate a state of PD as a practical and non-invasive tool to screen for voles with a high probability of hypeglycaemia. In addition, we discuss regional differences related to the development of diabetes in Scandinavian bank voles and the relevance of the Ljungan virus as proposed etiological agent.

Results

We found that median survival after onset of PD is at least 91 days (lower/upper quartiles = 57/134 days) with a maximum recording of at least 404 days survivorship. The development of PD did not influence the weight of Danish bank voles. The measures of accuracy when using PD as predictor of hyperglycaemia, i.e. sensitivity, specificity, positive predictive value, and negative predictive value, equalled 69%, 97%, 89%, and 89%, respectively.

Conclusion

The relatively long survival of Danish PD bank voles suggests potentials for this model in future studies of the long-term complications of diabetes, of which some observations are mentioned. Data also indicates that diabetes in Danish bank is not associated with a higher body weight. Finally, the method of using measurements of daily water intake to screen for voles with a high probability of hyperglycaemia constitutes a considerable refinement when compared to the usual, invasive, methods.

Screening newborns for candidate biomarkers of type 1 diabetes

Combining samples from a national neonatal screening programme with the information from a national health registry allow for unique opportunities in analysing newborn blood for protein changes that could predict eventual disease development. A nested case-control cohort (n = 54 cases, 108 controls) was analysed by proteomics as a new way of looking for biomarkers that could bolster prediction of T1D risk in newborns. Protein extraction and haemoglobin depletion were automated and samples were processed and analysed by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). The data set was reduced to the highest quality peaks and analysed using conditional logistic regression. A total of 25 protein peaks were found to differ between the two groups. The automated haemoglobin depletion provides a platform for further proteomics studies of individual patient material. The method opens a door to a wealth of patient material stored as dried blood spots.

Seasonality of month of birth differs between type 1 diabetes patients with pronounced beta-cell autoimmunity and individuals with lesser or no beta-cell autoimmunity

OBJECTIVE

To establish whether children with type 1 diabetes mellitus (T1D) with signs of pronounced beta-cell-specific autoimmunity as reflected by high autoantibody titers or positivity for several beta-cell-specific autoantibodies show a different pattern of month of birth (MOB) compared with children with T1D and low beta-cell autoimmunity and that of the general population.

RESEARCH DESIGN AND METHODS

Cosinor analysis was used to analyze MOB rhythmicity in Swedish children with new onset T1D (n = 572), in whom the glutamate decarboxylase autoantibody (GAD65Ab) titer was determined and compared with that in 833 healthy children, and in 505 children with T1D in Berlin, in whom the titers of autoantibodies to insulin, GAD65, and islet antigen-2 were compared with the MOB pattern in the general population (n = 446 571).

RESULTS

In both cohorts of children with T1D, we found that children with either a high GAD65Ab titer (above the 80th percentile) or positivity for three beta-cell-specific autoantibodies differed in their pattern of MOB from the healthy population.

CONCLUSIONS

Our past and present observations support the hypothesis that the autoimmune process leading to childhood T1D is in part triggered in the perinatal period by viral infections in genetically susceptible individuals. The present study suggests that the process is linked to titer levels of autoantibodies.

Type 1 diabetes risk analysis on dried blood spot samples from population-based newborns: design and feasibility of an unselected case-control study

Development of type 1 diabetes mellitus (T1D) may be triggered pre- or perinatally by multiple factors. Identifying new predisposing T1D markers or combinations of markers in a large, well-characterised case-control collection may be important for future T1D prevention. The present work describes the design and feasibility of a large and unselected case-control study, which will define and evaluate prediction criteria for T1D at the time of birth. Danish registries (Biological Specimen Bank for Neonatal Screening, and the National Discharge Registry) made it possible to identify and collect dried blood spots (DBS) from newborns who later developed T1D (cases) born 1981-2002. DBS samples from 2086 cases and two matching control subjects per case were analysed for genetic and immune factors that are associated with T1D: (a) candidate genes (HLA, INS and CTLA4), (b) cytokines and inflammatory markers, (c) islet auto-antibodies (GAD65A, IA-2A). The objective of the study was to define reliable prediction tools for T1D using samples available at the time of birth. In a unique approach, the study linked a large unselected and population-based sample resource to well-ascertained clinical databases and advanced technology. It combined genetic, immunological and demographic data to develop prediction algorithms. It also provided a resource for future studies in which new genetic markers can be included as they are identified.

Atherogenic vascular and lipid phenotypes in young patients with Type 1 diabetes are associated with diabetes high-risk HLA genotype

Expression of human leukocyte antigen (HLA) class II molecules on islet endothelial cells is a central vascular event in the pathogenesis of Type 1 diabetes. Previous studies demonstrated the ability of other vascular endothelial cells to express HLA and thereby to process islet autoantigens on their surface. We investigated whether the HLA-DQ2/8 genotype, which confers the highest risk for Type 1 diabetes, is associated with early atherosclerosis in youths with this disease. Brachial artery endothelium-dependent, flow-mediated dilation (BA-FMD) and carotid artery intima-media thickness (CA-IMT), as well as markers of systemic inflammation [C-reactive protein (CRP), fibrinogen, and orosomucoid], HbA(1C), LDL, HDL, and total cholesterol, were assessed in 86 children and adolescents with Type 1 diabetes (mean age and diabetes duration, 15 and 7 yr, respectively) between 2004 and 2006. HLA genotypes were determined in dried blood spots by an oligoblot hybridization method. As a result, HLA-DQ2/8 was detected in 34 patients (DQ2/8). When this group was compared with the remaining patients (non-DQ2/8, n = 52), there were no differences in age, diabetes duration, HbA(1C), body mass index, inflammatory markers, and IMT (P > or = 0.4). In the DQ2/8 group, LDL-to-HDL ratio was elevated compared with that in the non-DQ2/8 group (1.8 vs. 1.3, respectively; P = 0.001), whereas FMD did not significantly differ between the groups (5.3% vs. 6.7%, respectively; P = 0.08). When patients were further categorized in relation to CRP (cut-off value, 1 mg/l), BA-FMD was significantly lower (3%, P < 0.01), whereas LDL-to-HDL ratio increased further (2.2, P < 0.001) in the subgroup of DQ2/8 and CRP > or = 1 patients compared with the remaining three subgroups. These associations remained significant after adjustment for age, diabetes duration, and HbA(1C) by analysis of covariance. The brachial artery responses to nitroglycerine were similar in all subgroups. In conclusion, the diabetes-predisposing HLA-DQ2/8 genotype in children and adolescents with Type 1 diabetes interferes with endothelial and lipid-related mechanisms of early atherosclerosis, possibly in part through inflammatory pathways.

Predicting and preventing autoimmunity, myth or reality?

Many autoimmune diseases are chronic conditions that progress over the course of years, and are characterized by the presence of autoantibodies that precede the overt disease by months or years. As examples, the presence of two islet cell antibodies (ICA) are associated with a 50% risk of developing diabetes mellitus in 5 years, anticyclic citrullinated (anti-CCP) antibodies are found in the sera of rheumatoid arthritis (RA) patients a median of 4.5 years before the overt disease, and in systemic lupus erythematosus (SLE), patients accrue antibodies throughout a foreseen course during the 3-4 years prior to the clinical symptoms. This ability to predict autoimmune diseases, or rather their clinical manifestations, leads to the prospect of screening healthy individuals for autoantibodies. The importance of such a notion lies not only in the ability to prevent life-threatening manifestations, such as Addisonian's crisis and thyroid storm, but also in the ability to treat and even prevent overt autoimmune diseases. Among such documented treatment modalities are administration of aspirin in antiphospholipid syndrome, ursodeoxycholic acid in primary biliary cirrhosis (PBC), vitamin D in SLE and autoimmune thyroid diseases (AITD), and more. Although additional studies are still needed to fully assess these notions, as well as the appropriate screening strategies to apply them, one cannot ignore the prospect of predicting and preventing autoimmunity.

ADA Outstanding Scientific Achievement Lecture 2004. Thirty years of investigating the autoimmune basis for type 1 diabetes: why can't we prevent or reverse this disease?

Thirty years ago, a convergence of investigational observations lead to the now widely accepted notion that type 1 diabetes results from an autoimmune destruction of insulin-producing beta-cells in subjects genetically predisposed to the disease. Improvements in understanding of the natural history of type 1 diabetes, the biochemical identification of autoantigens, the discovery of spontaneous animal models for the disease, the availability of immune-modulating agents, and other important facets, including disease prediction, drove an early sense of optimism that the prevention of type 1 diabetes was possible and, in some research circles, that ability was thought to be within a not-to-distant reach. Unfortunately, those early expectations proved overly optimistic, and despite the aforementioned knowledge gains, the generation of improved investigational tools, the identification of methods to prevent the disease in animal models, and the formation of very large disease prevention trials, a means to prevent type 1 diabetes in humans continues to remain elusive. Believing in the concept of "informative failures" (a.k.a., wise people learn from their mistakes), this lecture reviews the knowledge base collected over this time period and, when combined with an analysis of those research experiences, sets forth a proposal for future investigations that will, hopefully, turn discoveries into a means for the prevention or reversal of type 1 diabetes.