Structural Changes of Cutaneous Immune Cells in Patients With Type 1 Diabetes and Their Relationship With Diabetic Polyneuropathy

BACKGROUND AND OBJECTIVES

Diabetic polyneuropathy (DPN) is a complication of diabetes characterized by pain or lack of peripheral sensation, but the underlying mechanisms are not yet fully understood. Recent evidence showed increased cutaneous macrophage infiltration in patients with type 2 diabetes and painful DPN, and this study aimed to understand whether the same applies to type 1 diabetes.

METHODS

The study included 104 participants: 26 healthy controls and 78 participants with type 1 diabetes (participants without DPN [n = 24], participants with painless DPN [n = 29], and participants with painful DPN [n = 25]). Two immune cells, dermal IBA1+ macrophages and epidermal Langerhans cells (LCs, CD207+), were visualized and quantified using immunohistological labeling and stereological counting methods on skin biopsies from the participants. The IBA1+ macrophage infiltration, LC number density, LC soma cross-sectional area, and LC processes were measured in this study.

RESULTS

Significant difference in IBA1+ macrophage expression was seen between the groups (p = 0.003), with lower expression of IBA1 in participants with DPN. No differences in LC morphologies (LC number density, soma cross-sectional area, and process level) were found between the groups (all p > 0.05). In addition, IBA1+ macrophages, but not LCs, correlated with intraepidermal nerve fiber density, Michigan neuropathy symptom inventory, (questionnaire and total score), severity of neuropathy as assessed by the Toronto clinical neuropathy score, and vibration detection threshold in the whole study cohort.

DISCUSSION

This study showed expressional differences of cutaneous IBA1+ macrophages but not LC in participants with type 1 diabetes-induced DPN compared with those in controls. The study suggests that a reduction in macrophages may play a role in the development and progression of autoimmune-induced diabetic neuropathy.

Glutamic acid decarboxylase and islet antigen 2 antibody profiles in people with adult-onset diabetes mellitus: a comparison between mixed ethnic populations in Singapore and Germany

AIM

To gain insight into the presence of islet cell autoimmunity in an ethnic Asian compared with a white European population.

METHODS

For this cross-sectional study we recruited people with adult-onset diabetes (age of diagnosis 20-60 years), at tertiary referral centres in Germany (n=1020) and Singapore (n=1088). Glutamic acid decarboxylase and islet antigen 2 antibodies were measured according to Islet Autoantibody Standardization Program protocols.

RESULTS

The prevalence of glutamic acid decarboxylase antibody positivity was 13.9% (95% CI 12.1-16.0; P<0.001) in the white European cohort compared with 6.8% (95% CI 5.5-8.4; P<0.001) in the Asian cohort. Glutamic acid decarboxylase antibody positivity was 11.4% (95% CI 7.7-16.6) in Indian, 6.0% (95% CI 3.6-9.9) in Malay and 5.8% (95% CI 4.3-7.7; P<0.001) in Chinese participants. In the white European participants, the prevalence of islet antigen 2 antibody positivity was 7.8% (95% CI 6.4-9.4) compared with 14.8% (95% CI 12.8-17.0; P<0.001) in the Asian cohort as a whole, and among the three ethnicities in the Asian cohort it was 12.4% (95% CI 8.6-17.7) in Indian, 16.8% (95% CI 12.6-22.2) in Malay and 15.7% (95% CI 13.2-18.6) in Chinese participants. Double antibody positivity was seen in 5.7% (95% CI 4.5-7.1) of white European participants compared with 1.6% (95% CI 1.0-2.5; P<0.01) of Asian participants. In the white European cohort, those who were glutamic acid decarboxylase autoantibody-positive had a lower BMI than those who were autoantibody-negative, but this trend was absent in the Asian cohort.

CONCLUSIONS

A marked prevalence of islet cell autoimmunity was observed in people with adult-onset diabetes. While glutamic acid decarboxylase antibodies were more frequent in the European cohort, islet antigen 2 antibody positivity was highest in the three ethnic groups in Singapore, suggesting ethnic-specific differences in antibody profiles.

Potential route of Th17/Treg cell dynamics in targeting type 1 diabetes and rheumatoid arthritis: an autoimmune disorder perspective

Cytokines, small secreted proteins, have a specific effect on the interactions and communications between cells. They play a pivotal role in the pathogenesis of autoimmune diseases. Factors in the breakdown of self-tolerance and the subsequent events leading to the induction of pathogenic responses remain unclear for most of the autoimmune diseases. Large numbers of studies have revealed a general scheme in which pro-inflammatory cytokines contribute to the initiation and propagation of autoimmune inflammation, whereas anti-inflammatory cytokines facilitate the regression of inflammation and thereby recovery from the disease. The interleukin (IL)-17/IL-23 axis that emerged as the new paradigm has compelled us to critically re-examine the cytokine-driven immune events in the pathogenesis and treatment of autoimmunity. T-helper 17 cells and Regulatory T cells are two lymphocyte subsets with opposing action. In this review, we discuss the mechanism that promotes development of these cells from common precursors and specific factors that impact their cell numbers and function. Also presented are findings that suggest how the equilibrium between pre-inflammatory T helper and regulatory T-cell subsets might be pharmacologically restored for therapeutic benefit, emphasising type-1 diabetes and rheumatoid arthritis. Furthermore, the emerging clinical data showing anti-IL-17 and anti-IL-23 treatments for their efficacy in treating immune-mediated inflammatory diseases are presented.

Maternal exposure to air pollution and type 1 diabetes--Accounting for genetic factors

BACKGROUND

Genetic and non-genetic factors probably act together to initiate and accelerate development of type 1 diabetes [T1D]. One suggested risk factor contributing to development of T1D is air pollution.

OBJECTIVE

The aim of the study was to investigate whether maternal exposure during pregnancy to air pollution, measured as nitrogen oxides [NOx] and ozone, in a low-dose exposure area was associated with the child developing T1D.

METHOD

In Scania (Skåne), the most southern county in Sweden, 84,039 infants were born during the period 1999-2005. By the end of April 2013, 324 of those children had been diagnosed with T1D. For each of those T1D children three control children were randomly selected and matched for HLA genotype and birth year. Individually modelled exposure data at residence during pregnancy were assessed for nitrogen oxides [NOx], traffic density and ozone.

RESULTS

Ozone as well as NOx exposures were associated with T1D. When the highest exposure group was compared to the lowest group an odds ratios of 1.62 (95% confidence interval [CI] 0.99-2.65) was observed for ozone in the second trimester and 1.58 (95% CI 1.06-2.35) for NOx in the third trimester.

CONCLUSION

This study indicates that living in an area with elevated levels of air pollution during pregnancy may be a risk factor for offspring T1D.

Design and in silico evaluation of an intraperitoneal-subcutaneous (IP-SC) artificial pancreas

Prandial glucose regulation is a major challenge for the artificial pancreas using subcutaneous insulin (without a feedforward bolus) due to insulin's slow absorption-peak (50-60 min). Intraperitoneal insulin, with a fast absorption peak (20-25 min), has been suggested as an alternative to address these limitations. An artificial pancreas using intraperitoneal insulin was designed and evaluated on 100 in silico subjects and compared with two designs using subcutaneous insulin with and without a feedforward bolus, following the three meal (40-70 g-carbohydrates) evaluation protocol. The design using intraperitoneal insulin resulted in a significantly lower postprandial blood glucose peak (38 mg/dL) and longer time in the clinically accepted region (13%) compared to the design using subcutaneous insulin without a feedforward bolus and comparable results to a subcutaneous feedforward bolus design. This superior regulation with minimal user interaction may improve the quality of life for people with type 1 diabetes mellitus.

High plasma levels of islet amyloid polypeptide in young with new-onset of type 1 diabetes mellitus

Aims/Hypothesis

Islet amyloid polypeptide (IAPP) is a beta cell hormone secreted together with insulin upon glucose stimulation. IAPP participates in normal glucose regulation, but IAPP is also known for its ability to misfold and form islet amyloid. Amyloid fibrils form through smaller cell toxic intermediates and deposited amyloid disrupts normal islet architecture. Even though IAPP and amyloid formation are much discussed in type 2 diabetes, our aim was to study the significance of IAPP in type 1 diabetes.

Results

Plasma IAPP levels in children and adolescents with newly diagnosed type 1 diabetes (n = 224) were analysed and concentrations exceeding 100 pmol/L (127.2 – 888.7 pmol/L) were found in 11% (25/224). The IAPP increase did not correlate with C-peptide levels.

Conclusions/Interpretation

Plasma levels of IAPP and insulin deviate in a subpopulation of young with newly-diagnosed type 1 diabetes. The determined elevated levels of IAPP might increase the risk for IAPP misfolding and formation of cell toxic amyloid in beta cells. This finding add IAPP-aggregation to the list over putative pathological factors causing type 1 diabetes.

Evaluation of a new durable insulin pen with memory function among people with diabetes and healthcare professionals

OBJECTIVES

The aim of the study was to evaluate durable insulin pens among people with diabetes (PwD) and healthcare professionals (HCPs), by comparing two durable insulin pens with memory function: NovoPen® 5 (NP5) and HumaPen® Memoir™ (HPM), and two durable insulin pens without memory function: HumaPen Luxura® (HPL) and ClikSTAR® (CS).

RESEARCH DESIGN AND METHODS

This cross-over, multicentre usability test was conducted in China, Germany and the UK. Participants evaluated all four pens in randomised order by performing handling and usability tasks related to everyday use during a face-to-face interview. Tasks, pens and preferences were rated by completing a questionnaire comprising of rating and open-ended questions.

RESULTS

NP5 was preferred by 51% of participants compared with HPM (22%, p < 0.01), HPL (12%, p < 0.01) and CS (15%, p < 0.01). Participants preferred the design of NP5 (in particular, appearance, length and robustness). Memory function for the two pens was rated equally by participants, but 54% of PwD rated NP5 as 'very easy' to learn to use versus 22% for HPM and significantly more HCPs found it 'very easy' to teach patients to use NP5 versus HPM (6-point rating scale; difference in mean score, p < 0.01). Substantially, more PwD would be confident in using NP5 (64%) compared with HPM (43%), HPL (49%) and CS (45%) (6-point rating scale; difference in mean score, p < 0.01).

CONCLUSIONS

NP5 was preferred by > 50% of PwD and HCPs. NP5 was more highly rated for design, memory function and ease of learning/teaching compared with HPM. Most PwD would be confident in using NP5 for administering daily insulin injections.

Disturbed zinc homeostasis in diabetic patients by in vitro and in vivo analysis of insulinomimetic activity of zinc

Disturbances of zinc homeostasis have been observed in several diseases, including diabetes mellitus. To further characterize the association between zinc and diabetes, we recruited 75 patients with type 1 or type 2 diabetes and 75 nondiabetic sex-/age-matched control subjects in order to analyze differences concerning human zinc transporter 8 (hZnT-8) expression, single nucleotide polymorphisms (SNPs) in the genes of hZnT-8 as well as metallothionein 1A and serum/intracellular zinc. Furthermore, we investigated the relation between insulin and zinc homeostasis in type 2 diabetic subjects and consolidated our results by in vitro analysis of the effect of insulin on cellular zinc status and by analysis of the modulation of insulin signal transduction by intracellular zinc homeostasis. Concerning the expression of hZnT-8 and the SNPs analyzed, we did not observe any differences between diabetic and control subjects. Serum zinc was significantly lower in diabetic patients compared to controls, and intracellular zinc showed the same tendency. Interestingly, type 2 diabetes patients treated with insulin displayed lower serum zinc compared to those not injecting insulin. In vitro analyses showed that insulin leads to an increase in intracellular zinc and that insulin signaling was enhanced by elevated intracellular zinc concentrations. In conclusion, we show that type 1 and type 2 diabetic patients suffer from zinc deficiency, and our results indicate that zinc supplementation may qualify as a potential treatment adjunct in type 2 diabetes by promoting insulin signaling, especially in zinc-deficient subjects.

DomainRBF: a Bayesian regression approach to the prioritization of candidate domains for complex diseases

Background

Domains are basic units of proteins, and thus exploring associations between protein domains and human inherited diseases will greatly improve our understanding of the pathogenesis of human complex diseases and further benefit the medical prevention, diagnosis and treatment of these diseases. Within a given domain-domain interaction network, we make the assumption that similarities of disease phenotypes can be explained using proximities of domains associated with such diseases. Based on this assumption, we propose a Bayesian regression approach named "domainRBF" (domain Rank with Bayes Factor) to prioritize candidate domains for human complex diseases.

Results

Using a compiled dataset containing 1,614 associations between 671 domains and 1,145 disease phenotypes, we demonstrate the effectiveness of the proposed approach through three large-scale leave-one-out cross-validation experiments (random control, simulated linkage interval, and genome-wide scan), and we do so in terms of three criteria (precision, mean rank ratio, and AUC score). We further show that the proposed approach is robust to the parameters involved and the underlying domain-domain interaction network through a series of permutation tests. Once having assessed the validity of this approach, we show the possibility of ab initio inference of domain-disease associations and gene-disease associations, and we illustrate the strong agreement between our inferences and the evidences from genome-wide association studies for four common diseases (type 1 diabetes, type 2 diabetes, Crohn's disease, and breast cancer). Finally, we provide a pre-calculated genome-wide landscape of associations between 5,490 protein domains and 5,080 human diseases and offer free access to this resource.

Conclusions

The proposed approach effectively ranks susceptible domains among the top of the candidates, and it is robust to the parameters involved. The ab initio inference of domain-disease associations shows strong agreement with the evidence provided by genome-wide association studies. The predicted landscape provides a comprehensive understanding of associations between domains and human diseases.

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.

Zinc and diabetes--clinical links and molecular mechanisms

Zinc is an essential trace element crucial for the function of more than 300 enzymes and it is important for cellular processes like cell division and apoptosis. Hence, the concentration of zinc in the human body is tightly regulated and disturbances of zinc homeostasis have been associated with several diseases including diabetes mellitus, a disease characterized by high blood glucose concentrations as a consequence of decreased secretion or action of insulin. Zinc supplementation of animals and humans has been shown to ameliorate glycemic control in type 1 and 2 diabetes, the two major forms of diabetes mellitus, but the underlying molecular mechanisms have only slowly been elucidated. Zinc seems to exert insulin-like effects by supporting the signal transduction of insulin and by reducing the production of cytokines, which lead to beta-cell death during the inflammatory process in the pancreas in the course of the disease. Furthermore, zinc might play a role in the development of diabetes, since genetic polymorphisms in the gene of zinc transporter 8 and in metallothionein (MT)-encoding genes could be demonstrated to be associated with type 2 diabetes mellitus. The fact that antibodies against this zinc transporter have been detected in type 1 diabetic patients offers new diagnostic possibilities. This article reviews the influence of zinc on the diabetic state including the molecular mechanisms, the role of the zinc transporter 8 and MT for diabetes development and the resulting diagnostic and therapeutic options.

Variations in incidence of type 1 diabetes in different municipalities of stockholm

This article reports a test of the hypothesis that municipalities within the County of Stockholm have varying incidence rates of type 1 diabetes (T1D), suggesting a strong etiologic environmental component to the disease. The study group included T1D patients in the age group from birth to 18 years who were diagnosed each year from 20 municipalities in Stockholm County during the 1990-2003. Specific incidence rates by age, sex, and socioeconomic characteristics (income level, proportion of taxpayers, proportion of foreigners, population density and green cover) were estimated annually together with age standardization. chi(2) analyses were used for the statistical assessment of variability in incidence. During the study period, 733 newly diagnosed T1D patients aged 0-18 years were recorded from the 20 municipalities under study. The overall age-standardized incidence in these 20 municipalities was 24.38 (22.65-26.21) per 100,000, with 45.35 (32.08-62.29) as highest and 13.41 (9.53-18.35) as lowest estimated incidence. For all socioeconomic variables statistically significant heterogeneity was demonstrated in the standardized incidence rate. High green index was positively associated with the incidence of T1D, as was low population density. For the three remaining socioeconomic variables no clear patterns of associations with incidence of T1D were seen. This study demonstrates a considerable and statistically significant variation between the lowest and highest values in the incidence and prevalence rates for T1D in municipalities of Stockholm County. Such variation seems unlikely to be explained by genetic differences since the population is homogeneous. Our study provides support for the hypothesis that environmental factors have a major influence on the pathogenesis of T1D.

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.

Spectrum of Autoantibodies in Tunisian Adult Type 1 Diabetes Mellitus

As an autoimmune disease, type 1 diabetes mellitus (T1DM) is characterized by the presence of several autoantibodies. The aim of this study was to examine a broad spectrum of antibodies in Tunisian adult T1DM and to compare their prevalence with a healthy control group. Two hundred sixty-one diabetics and 100 healthy blood donors were enrolled in this study. Indirect immunofluorescence was performed for the detection of islet cell, antiendomysial, antinuclear, antimitochondrial, antismooth muscle, antireticulin, and antikeratin antibodies. Enzyme-linked immunosorbent assay was used for measuring anticardiolipin, antigliadin, antitransglutaminase, and antithyroperoxidase antibodies. Latex agglutination was used for the detection of rheumatoid factors. As expected, islet cell antibodies were the most frequent (33.7%). Antigliadin, antithyroperoxidase, and antikeratin antibodies were relatively frequent (18%, 15.3%, and 10.3%, respectively) and were statistically more prevalent in diabetics than in controls. There was no correlation between diabetes duration and any autoantibody, except for islet cell antibodies that were more frequent at the onset of diabetes. Several autoantibodies nonspecific of diabetes are frequent in diabetic patients, which may be associated with or predictors of some autoimmune diseases, and can also reflect a special profile of autoimmunity in diabetics in comparison to healthy controls.

[Susceptibility markers in Tunisian first-degree relatives of patients with type 1 diabetes]

To identify the profile of anti-pancreas autoantibodies and elucidate the HLA DRB1, DQB1 polymorphism in Tunisian first-degree relatives of patients with type 1 diabetes, we recruited 96 relatives from 21 families with at least one diabetic child. Islet cell antibodies (ICA) were detected by immunofluorescence on monkey pancreas; glutamate decarboxylase (GADA), IA2 (IA2-A) and insulin (IAA) antibodies were measured by RIA. HLA class II DRB1 and DQB1 alleles were typed by PCR-SSP. ICA, GADA, IA2-A and IAA were found in respectively 11.5, 4.2, 5.2 and 8.3% of relatives. Twenty-two out of 96 had at least one antibody and 20 out of these 22 had a susceptibility allele (DRB1*03, DRB1*04, DQB1*02 or DQB1*0302) with or without protective allele (DRB1*11, DRB1*13, DRB1*15 or DQB1*06). All of the 5 relatives having 2 autoantibodies or more carried the DRB1*04-DQB1*0302 susceptible haplotype. In conclusion, this observational study confirms in a Tunisian population known epidemiological data and demonstrates the usefulness of follow-up to determine the predictive value of studied markers.

Insulin gene VNTR, CTLA-4 +49A/G and HLA-DQB1 alleles distinguish latent autoimmune diabetes in adults from type 1 diabetes and from type 2 diabetes group

Recent research has underlined the need to explore pathogenic, genetic and clinical spectrum of adult onset autoimmune diabetes, also known as latent autoimmune diabetes in adults (LADA). We aimed to investigate whether genetic factors that are associated with type 1 diabetes (T1D) susceptibility, namely HLA-DQB1 alleles, cytotoxic T-lymphocyte antigen 4 gene (CTLA-4) and insulin gene (INS) polymorphisms, are also associated with an atypical subset of patients diagnosed with type 2 diabetes (T2D). The case-control study included 70 T1D, 305 T2D and 252 nondiabetic controls. The T2D group was divided into atypical T2D (LADA, n = 61) or typical T2D (n = 244) subgroups based on the presence of at least one pancreas-specific antibody. Our data suggested that HLA-DQB1 alleles of all three risk classes, INS variable number of tandem repeat (VNTR) I/I and CTLA-4 +49 GG or AG genotypes, were independent risk factors for developing LADA and could be used as a diagnostic tool to discriminate between LADA and T2D. Additionally, there was an increased association between LADA and CTLA-4 diabetes-susceptibility genotypes and decreased association with INS VNTR and high-risk HLA-DQB1 alleles, compared with T1D. Our study suggested the need for further investigation into the genetic background and functional genomics of LADA in comparison with T1D and T2D.

Swedish families' lived experience when a child is first diagnosed as having insulin-dependent diabetes mellitus: An ongoing learning process

Sweden has the second highest nationwide incidence of childhood diabetes in Europe, and it is rapidly increasing. The diagnosis of Type 1 insulin-dependent diabetes mellitus has been indicated as a crisis in the life of the individual and family. The purpose of this study was to elucidate the whole family's lived experience when a child in the family is diagnosed as having diabetes. It was designed as a longitudinal, descriptive, inductive study including qualitative interviews. Family members in 12 families were recruited from a children's university hospital in Sweden to participate in a series of three interviews: when first diagnosed, and 1 and 3 years after diagnosis. This article derives from the first interview. All invited families agreed to participate and were interviewed 1 to 3 months after diagnosis using a hermeneutic phenomenological approach. The family's lived experience was identified as an ongoing learning process including learning about the inevitable and learning about the extent. The learning process was experienced as a recurrent phenomenon when the family was exposed to new situations or contexts. Therefore, individualized treatment may reduce the difficulties experienced in coping with the diabetic management regimen after discharge, thus making the transition smoother.

Expression, purification, and refolding of mouse islet neogenesis associated protein-related protein for NMR studies

Islet neogenesis associated protein-related protein (INGAPrP) is thought to be involved in the differentiation of non-insulin-producing cells to insulin-secreting cells. INGAPrP is a mouse gene product that has a 72% identical amino acid sequence to a known islet-generating factor, hamster islet-neogenesis-associated protein (INGAP), which acts by differentiating pancreatic ductal cells into beta-cells. The three-dimensional structure of these proteins is unknown. The structure would provide information about the conformation of the active portion of INGAP, the so-called INGAP pentadecapeptide, leading to a well-defined target for rational drug design. An efficient procedure for the production of INGAPrP would facilitate the process of structure determination. We have successfully produced and isolated (15)N-labeled INGAPrP by expression in Escherichia coli Rosetta (DE3) cells in Spectra-9 media followed by a two-step purification and refolding protocol. The hexahistidine tag engineered at the N-terminus of the protein is used in the first step for standard immobilized-metal affinity chromatography purification under denaturing conditions. The secondary purification step utilizes a gel permeation chromatography column, producing homogeneous INGAPrP as well as refolding the protein. To verify that the protein was folded, we performed a (1)H-(15)N HSQC NMR experiment that showed excellent dispersion of signals, indicative of a folded protein. We also performed circular dichroism experiments, which demonstrated the presence of secondary structure. In summary, we report the first expression and isolation of INGAPrP, as well as demonstrate that our method produces a folded protein, which is necessary for structure determination.

Altered chemokine levels in individuals at risk of Type 1 diabetes mellitus

AIMS

The hypothesis was tested in an exploratory study that individuals at high risk of developing Type 1 diabetes mellitus have altered systemic levels of cytokines and chemokines.

SUBJECTS AND METHODS

Forty-two non-diabetic first-degree relatives of patients with Type 1 diabetes mellitus were recruited. Of these, 18 had multiple islet autoantibodies (islet cell antibody, glutamic acid decarboxylase antibody, IA-2 antibody). Follow-up for 9-11 years confirmed high vs. moderate diabetes risk in islet autoantibody-positive vs. -negative relatives. Cytokines and chemokines were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Serum concentrations of classic Th1-associated cytokines (IFN-gamma, IL-12, IL-18) or Th2/Treg-associated cytokines (IL-5, IL-10, IL-13) did not significantly differ in high vs. moderate diabetes risk group. However, of six chemokines analysed, levels of CCL3 and CCL4 were increased (P = 0.0442 and P = 0.0334) while CCL2 was decreased (P = 0.0318) in the multiple islet autoantibody-positive group. No significant differences were seen for CCL5, CCL11, CXCL10. There was a significant correlation between the two closely related chemokines CCL3 and CCL4 in individuals at risk (r = 0.84, P = 0.00005), but not in the autoantibody-negative group.

CONCLUSION

Relatives at high risk of developing Type 1 diabetes mellitus have abnormal cellular immune regulation at the level of systemic chemokines. The up-regulation of CCL3 and CCL4 vs. down-regulation of CCL2 suggests opposed functions of these chemokines in the disease process. These findings need to be confirmed by independent studies.

Simultaneous Measurement of 25 Inflammatory Markers and Neurotrophins in Neonatal Dried Blood Spots by Immunoassay with xMAP Technology

Background: Inflammatory reactions and other events in early life may be part of the etiology of late-onset diseases, including cerebral palsy, autism, and type 1 diabetes. Most neonatal screening programs for congenital disorders are based on analysis of dried blood spot samples (DBSS), and stored residual DBSS constitute a valuable resource for research into the etiology of these diseases. The small amount of blood available, however, limits the number of analytes that can be determined by traditional immunoassay methodologies.

Methods: We used new multiplexed sandwich immunoassays based on flowmetric Luminex® xMAP technology to measure inflammatory markers and neutrophins in DBSS.

Results: The high-capacity 25-plex multianalyte method measured 23 inflammatory and trophic cytokines, triggering receptor expressed on myeloid cells-1 (TREM-1), and C-reactive protein in two 3.2-mm punches from DBSS. It also measured 26 cytokines and TREM-1 in serum. Standards Recovery in the 25-plex method were 90%–161% (mean, 105%). The low end of the working range for all 25 analytes covered concentrations found in DBSS from healthy newborns. Mean recovery of exogenous analytes added at physiologic concentrations in DBSS models was 174%, mean intra- and interassay CVs were 6.2% and 16%, respectively, and the mean correlation between added and measured analytes was r2 = 0.91. In DBSS routinely collected on days 5–7 from 8 newborns with documented inflammatory reactions at birth, the method detected significantly changed concentrations of inflammatory cytokines. Measurements on DBSS stored at −24 °C for &gt;20 years showed that most cytokines are detectable in equal concentrations over time.

Conclusions: The method can reliably measure 25 inflammatory markers and growth factors in DBSS. It has a large potential for high-capacity analysis of DBSS in epidemiologic case–control studies and, with further refinements, in neonatal screening.

An efficient preparation of polyanionic affinity agent and its evaluation for the measurement of glycated hemoglobin

An efficient method was developed for the preparation of polyanionic affinity agent (3), a key component in the measurement of glycated hemoglobin (GHb). Glycated hemoglobin is an important clinical marker for diagnosis of patients with diabetes and useful to monitor the management of disease. The affinity agent (3) was prepared based on coupling reaction between poly(acrylic acid) (1) and 3-aminophenylboronic acid (2) in water. The critical features of this polymeric affinity agent (3), such as size, boronic acid incorporation ratio and concentration, on the measurement of glycated hemoglobin were evaluated. It was found that the agent (3) prepared using poly(acrylic acid) (1) with 225 kDa molecular weight gave optimal GHb measurement. The performance test results demonstrated that the boronic acid incorporation ratio and concentration of affinity agent (3) play a critical role in the assay and determines the precision of glycated hemoglobin measurement.

Hepatitis C virus infection-related Type 1 diabetes mellitus

BACKGROUND

Hepatitis C virus (HCV) has been associated with Type 2 diabetes mellitus, and many other viral infections have been associated with Type 1 diabetes mellitus (Type 1 DM). An association between HCV and Type 1 DM, however, has never been reported. We report the case of a 66-year-old man who developed Type 1 DM 1 year after a blood transfusion-related HCV infection. Testing of serum specimens obtained in the weeks following blood transfusion demonstrated evidence of both acute HCV infection and development of Type 1 DM-related autoantibodies.

CASE REPORT

A 66-year-old Taiwanese male received blood transfusions during coronary artery bypass surgery in 1987. Serum specimens, obtained as part of a study on post-transfusion hepatitis, demonstrated that the patient had no evidence of hepatitis C prior to transfusion, but developed acute HCV infection after transfusion. One year later, the patient, who had no personal or family history of diabetes, presented with diabetic ketoacidosis, and tests for C-peptide confirmed that he had Type 1 DM. Testing of pre- and post-operative serum specimens demonstrated that the patient developed positive tests for islet cell and glutamic acid decarboxylase antibodies 4 weeks after transfusion, concurrent with the development of acute HCV infection.

CONCLUSIONS

The simultaneous development of HCV infection and diabetes-related autoantibodies suggest a relationship between HCV and Type 1 DM.

Type 1 diabetes is insulin -2221 MspI and CTLA-4 +49 A/G polymorphism dependent

BACKGROUND

Several studies have demonstrated an association of type 1 diabetes with specific alleles of HLA class II molecules, as with polymorphisms of insulin gene region. The aim of our study was to evaluate the interaction of insulin -2221 MspI polymorphism to type 1 diabetes susceptibility in connection with autoimmunity associated gene--CTLA-4 polymorphism.

MATERIALS AND METHODS

Insulin -2221 MspI C/T and CTLA-4 +49 A/G polymorphisms were detected by restriction fragment-length polymorphism analysis or oligonucleotide hybridization in type 1 (n = 69), type 2 diabetes (n = 301) patients and 158 healthy controls. Regression model adjusted for age, gender and gene polymorphisms was studied.

RESULTS

C-allele of insulin -2221 MspI and G-allele of +49 CTLA-4 were significant risk factors for type 1 diabetes (crude OR 3.53 and 1.59, respectively) and this impact increased in the homozygous form of both alleles. The regression model supported the idea of insulin CC and CTLA-4 GG genotypes for an independent and clearly significant risk for developing type 1 diabetes. We could not detect any significant correlation between investigated polymorphisms and type 2 diabetes.

CONCLUSIONS

There exists a significant association between the C-allele of -2221 MspI in the insulin gene and type 1 diabetes. The CTLA-4 G-allele is also positively correlated with type 1 diabetes. According to the regression model the investigated gene polymorphisms are independent risk factors for development of type 1 diabetes in the Estonian population. We propose that -2221 MspI is a good marker for evaluation of risk of insulin gene haplotype in type 1 diabetes patients.

Population stratification in the candidate gene study: fatal threat or red herring?

Advances in molecular genetics have provided behavioral scientists with a means of investigating the influence of genetic factors on human behavior. Unfortunately, recent candidate gene studies have produced inconsistent results, and a frequent scapegoat for the lack of replication across studies is the threat of population stratification. This review of the literature on population stratification suggests that the threat may be a red herring. Reliable findings will require improved specification and measurement of the behavioral phenotypes in question, a renewed focus on internal validity, and the specification and testing of genetic factors in the context of longitudinal multivariate models. In this respect, behavioral scientists are well suited to investigating genetic factors that influence psychological mechanisms.

Differences in the genetic background of latent autoimmune diabetes in adults (LADA) and type 1 diabetes mellitus

OBJECTIVES

According to the recent classification of diabetes mellitus the Latent Autoimmune Diabetes in Adults (LADA) belongs to the group of type 1 autoimmune diabetes, as a slowly progressive form. Our aim was to determine (i) the prevalence of HLA-DRB1 and DQB1 genotypes, and (ii) to determine the tumor necrosis factor (TNF) alpha promoter polymorphism at position -308 (the G-->A substitution, designated the TNF2 allele) in patients with type 1 diabetes and with LADA compared with the healthy population.

METHODS

The major histocompatibility complex (MHC) II genotypes and the TNF alpha promoter polymorphism were determined by PCR method. We examined 69 type 1 diabetic and 42 LADA patients. As control samples of 336 cadaver kidney donors and 138 volunteers were used.

RESULTS

Both type 1 diabetes mellitus and LADA were positively associated with the DRB1*04-DQB1*0302 (DR4/DQ8) haplotype (P=0.00001, and P=0.0005, respectively), and negatively associated with the DRB1*11-DQB1*0301 (DR11/DQ7) haplotype (P=0.00006, and P=0.007, respectively) compared with control population. There were differences between the two disease entities in the frequency of the DRB1*03-DQB1*02 (DR3/DQ2) haplotype (P=0.00008 vs. P=0.177) compared with control group. The presence of the TNF2 allele was significantly lower in LADA than type I diabetes (P=0.022) or control group (P=0.017).

CONCLUSION

Our findings indicate that there are marked differences in the genetic background of type 1 diabetes and LADA. The low presence of TNF2 allele (known to be associated with high amount of TNF alpha production) in LADA could be one of the factors responsible for the relatively slow progression.

An association of autoantibody status and serum cytokine levels in type 1 diabetes

At onset of type 1 diabetes, the islet autoantibody status of patients has been reported to predict progression of the disease. We therefore tested the hypothesis that the systemic immunoregulatory balance, as defined by levels of circulating cytokines and chemokines, is associated with islet autoantibody status. In 50 patients with recent-onset type 1 diabetes, antibodies to GAD and insulinoma-associated antigen 2 (IA-2) were analyzed by radioimmunoassay; cytoplasmic islet cell antibodies were determined by indirect immunofluorescence. Cytokine and chemokine concentrations were measured by rigidly evaluated double antibody enzyme-linked immunosorbent assay. Of four classically defined Th1/Th2 cytokines (gamma-interferon, interleukin [IL]-5, IL-10, IL-13), none showed an association with multiple autoantibody positivity. Of six mediators mainly produced by innate immunity cells, three were associated with multiple autoantibody status (IL-18 increased, MIF and MCP-1 decreased) and three were unaffected (IL-12, MIP-1beta, IP-10). GAD and/or IA-2 antibody titers negatively correlated with systemic concentrations of MIF, MIP-1beta, and IL-12. Combining the data of several cytokine and chemokine levels made it possible to predict islet antibody positivity in individual patients with 85% sensitivity and 94% specificity. These data suggest a close association of islet antibody status with systemic immunoregulation in type 1 diabetes.

Glycated hemoglobin: a useful post-mortem reference marker in determining diabetes

Glycated hemoglobin (HbA(1c)) has been demonstrated to be a useful marker for long-term glucose control in diabetes. This parameter characterizes each non-enzymatic fixation of glucose on hemoglobin. It is a useful test in addition to periodic glycemia controls since it reflects the mean glycemia of the past 60 days. We studied the conservation of HbA(1c) at 4 degrees C as a function of time with different anti-coagulants and preservatives (3, 6 months, 1 year). A total of 106 tests were performed using the high performance liquid chromatography (HPLC) method dedicated to the semi-automatic analysis of HbA(1c) (Bio-Rad) and we applied the method in forensic cases. Conservation at 4 degrees C was good for as long as 3 months in blood samples collected with fluoride and 6 months in samples collected in a dry or in a heparinized tube. In non-diabetic subjects, HbA(1c) reference values obtained from forensic samples were identical to those of living controls (3.5-6.25% of total hemoglobin). All positive HbA(1c) results were confirmed by a medical evaluation. This method was successfully applied to five forensic cases. In cases of increased acetonemia, acetone or isopropanol are easily measured. However, in some unexplained post-mortem circumstances, increased HbA(1c) permits to differentiate alcoholic or starvation ketoacidosis from the diabetic cases. Glycated hemoglobin should, therefore, be considered the forensic marker of choice in the post-mortem diagnosis of a diabetic disorder and demonstrates its usefulness in post-mortem validation.

MRI of insulitis in autoimmune diabetes

Development of imaging techniques that would allow the mapping of immune cells in vivo could greatly aid our understanding of a number of inflammatory and autoimmune diseases. The current study focused on imaging of autoimmune destruction of the insulin-producing pancreatic beta-cells by cytotoxic lymphocytes, the cause of insulin-dependent diabetes mellitus (IDDM; Type 1 diabetes). Using high-resolution MR microscopy and a conventional clinical MR imaging system, it was possible to visualize the infiltration of immune cells in the diabetic mouse pancreas. Mouse lymphocytes were visualized by magnetically labeling them with recently developed magnetic nanoparticles (CLIO-Tat). The results from this study could potentially lead to detection of immune infiltration during diabetes formation in vivo, which would be one of the earliest parameters of disease development.

Combinations of beta cell specific autoantibodies at diagnosis of diabetes in young adults reflects different courses of beta cell damage

To explore the natural course of beta cell function in recent onset diabetes, a subgroup (n=157) of all incident cases (n=879) 15-34 years old, 1992-1993 in Sweden, and with positivity for at least one autoantibody of islet cell antibodies (ICA), glutamic acid decarboxylase antibodies (GADA) or tyrosine phosphatase antibodies (IA-2A) were followed prospectively for the first four years with annual analysis of C-peptide. The aim was to relate the course of beta cell function, measured as C-peptide, in early diabetes with the presence of different islet autoantibodies at diagnosis. We found that patients positive for ICA alone (n=11) had significantly higher C-peptide levels both at diagnosis and during the first three years compared with the other patients (n=146; p=0.022, p<0.001, p=0.004 and p=0.0022). Patients positive for GADA alone or in combination with other antibodies (n=125) had significantly lower C-peptide during the first three years after diagnosis compared with the other patients (n=32, p<0.001, p=0.0011 and p=0.0136). Patients with two or three autoantibodies had C-peptide levels similar to levels found in patients positive only for GADA. However, after four years, there were no significant differences between any of the groups of different autoantibody combinations. At diagnosis, 55% (86/157) of the patients had C-peptide levels above the lower normal range of 0.25 nmol/l, but the frequency of patients with beta cell function above this level decreased after two years to 41% (65/157; p=0.035) and after four years to 22% (35/157; p=0.0041). It is concluded that young adult diabetic patients positive only for ICA at diagnosis have a better preserved beta cell function with higher levels of C-peptide during the first three years compared with patients positive for GADA alone or in combinations with other autoantibodies.

The HLA-DQB alleles and amino acid variants of the vitamin D-binding protein in diabetic patients in Alsace

BACKGROUND

The HLA-DQB1 chain, in particular the amino acid in position 57, and genetic variants of the vitamin D-binding protein (DBP) have been reported to be associated with type 1 diabetes. There are two known polymorphisms in exon 11 of the DBP gene resulting in amino acid variants: codons 416 GAT --> GAG (Asp --> Glu) and 420 ACG --> AAG (Thr --> Lys). We compared distribution of DQB1 alleles and amino acid variants of DBP in type 1 diabetic patients (n = 44) in the Alsacian population and in healthy controls (n = 58).

METHODS

The second exon of the DQB1 gene and exon 11 of DBP were analyzed by restriction mapping after polymerase chain reaction.

RESULTS

A significant enrichment in DQB1 alleles encoding for an amino acid different from Asp in position 57 (NA) was observed in diabetic subjects as compared to controls (94.3 vs. 32.8%; p < 0.001). Combinations other than Ala/Ala carried the highest relative risk (OR = 52; p < 0.001). The analysis of the polymorphism in exon 11 of DBP showed a significant difference in the allele frequency of the HaeIII site, but not of the StyI site between patients and controls. Allele frequencies of HaeIII in diabetic subjects were 36% and 64% for Asp and Glu respectively (p < 0.001; chi(2) = 29.5). The frequency of Asp/Asp and Glu/Glu genotypes was increased in controls and diabetic subjects respectively. DBP alleles in individuals carrying the DQB1 NA combination revealed that 46.6% of diabetics were DBP Asp/Glu, but this was not statistically significant using the Fisher exact test (16/31 vs. 0/3; p = 0.23).

CONCLUSIONS

The study of the DQB1 chain confirmed the value of alleles encoding for an amino acid different from Asp in position 57 (NA) in the susceptibility to type 1 diabetes. The allele frequency of the HaeIII site, but not of the StyI site, differed between patients and controls (HaeIII p < 0.001; StyI p > 0.05).