Residual insulin secretion at diagnosis of type 1 diabetes is independently associated with both, age of onset and HLA genotype

Residual insulin secretion in individuals with type 1 diabetes in Finland: longitudinal and cross-sectional analyses

BACKGROUND

Contrary to the presumption that type 1 diabetes leads to an absolute insulin deficiency, many individuals with type 1 diabetes have circulating C-peptide years after the diagnosis. We studied factors affecting random serum C-peptide concentration in individuals with type 1 diabetes and the association with diabetic complications.

METHODS

Our longitudinal analysis included individuals newly diagnosed with type 1 diabetes from Helsinki University Hospital (Helsinki, Finland) with repeated random serum C-peptide and concomitant glucose measurements from within 3 months of diagnosis and at least once later. The long-term cross-sectional analysis included data from participants from 57 centres in Finland who had type 1 diabetes diagnosed after 5 years of age, initiation of insulin treatment within 1 year from diagnosis, and a C-peptide concentration of less than 1·0 nmol/L (FinnDiane study) and patients with type 1 diabetes from the DIREVA study. We tested the association of random serum C-peptide concentrations and polygenic risk scores with one-way ANOVA, and association of random serum C-peptide concentrations, polygenic risk scores, and clinical factors with logistic regression.

FINDINGS

The longitudinal analysis included 847 participants younger than 16 years and 110 aged 16 years or older. In the longitudinal analysis, age at diagnosis strongly correlated with the decline in C-peptide secretion. The cross-sectional analysis included 3984 participants from FinnDiane and 645 from DIREVA. In the cross-sectional analysis, at a median duration of 21·6 years (IQR 12·5-31·2), 776 (19·4%) of 3984 FinnDiane participants had residual random serum C-peptide secretion (>0·02 nmol/L), which was associated with lower type 1 diabetes polygenic risk compared with participants without random serum C-peptide (p<0·0001). Random serum C-peptide was inversely associated with hypertension, HbA1c, and cholesterol, but also independently with microvascular complications (adjusted OR 0·61 [95% CI 0·38-0·96], p=0·033, for nephropathy; 0·55 [0·34-0·89], p=0·014, for retinopathy).

INTERPRETATION

Although children with multiple autoantibodies and HLA risk genotypes progressed to absolute insulin deficiency rapidly, many adolescents and adults had residual random serum C-peptide decades after the diagnosis. Polygenic risk of type 1 and type 2 diabetes affected residual random serum C-peptide. Even low residual random serum C-peptide concentrations seemed to be associated with a beneficial complications profile.

FUNDING

Folkhälsan Research Foundation; Academy of Finland; University of Helsinki and Helsinki University Hospital; Medical Society of Finland; the Sigrid Juselius Foundation; the "Liv and Hälsa" Society; Novo Nordisk Foundation; and State Research Funding via the Helsinki University Hospital, the Vasa Hospital District, Turku University Hospital, Vasa Central Hospital, Jakobstadsnejdens Heart Foundation, and the Medical Foundation of Vaasa.

High Residual β-cell Function in Chinese Patients With Autoimmune Type 1 Diabetes

OBJECTIVE

The destruction of pancreatic β cells causes type 1 diabetes mellitus (T1D), an autoimmune disease. Studies have demonstrated that there is heterogeneity in residual β-cell function in Caucasians; therefore, we aimed to evaluate β-cell function in Chinese autoimmune T1D patients.

METHODS

β-cell function was determined using oral glucose tolerance testing or standardized steamed bread meal tolerance test in 446 participants with autoantibody-positive T1D. Clinical factors, such as age onset, sex, duration, body mass index, autoantibodies, other autoimmune diseases, diabetic ketoacidosis, hypoglycemia events, glycosylated hemoglobin, and insulin dose, were retrieved. We also analyzed single nucleotide polymorphism (SNP) data for C-peptides from 144 participants enrolled in the Chinese-T1D genome-wide association study.

RESULTS

Of 446 T1D patients, 98.5%, 97.4%, 86.9%, and 42.6% of individuals had detectable C-peptide values (≥ 0.003 nmol/L) at durations of < 1 year, 1 to 2 years, 3 to 6 years, and ≥ 7 years, respectively. A total of 60.7% of patients diagnosed at ≥ 18 years old and 15.8% of those diagnosed at < 18 years had detectable C-peptide after ≥ 7 years from the diagnosis. Furthermore, the patients diagnosed at ≥ 18 years old had higher absolute values of stimulated C-peptide (≥ 0.2 nmol/L). Diabetic ketoacidosis, hypoglycemia events, and insulin doses were shown to be associated with β-cell function. SNPs rs1770 and rs55904 were associated with C-peptide levels.

CONCLUSION

Our results have indicated that there are high residuals of β-cell mass in Chinese patients with autoimmune T1D. These findings may aid in the consideration of therapeutic strategies seeking prevention and reversal of β-cell function among Chinese T1D patients.

Fatty Acid Profiles and Their Association With Autoimmunity, Insulin Sensitivity and β Cell Function in Latent Autoimmune Diabetes in Adults

BACKGROUND

The pathogenesis of the progressive loss of beta cell function latent autoimmune diabetes in adults (LADA) remains still elusive. We aim to study the fatty acid (FA) profile in LADA.

SUBJECTS AND METHODS

Data from 116 patients with diabetes and GADA and 249 diabetes controls without GADA selected by Propensity Score Matching were collected. FA was analyzed with liquid chromatography-tandem mass spectrometry analysis.

RESULTS

Principal factor analysis found component 1 explains 82.6% of total variance contained fatty acids from a mixed of lard oil, seafood, and vegetable diet, followed by diet predominantly from vegetable oil, a diet of high fat diet, and a diet of seafood diet. The FA heatmap looked clearly different among the three groups with more similar type 1 (t1dm) and LADA fatty acid profile. n-3 α-linolenic acid (ALA), n-3 long chain polyunsaturated fatty acid (n-3 LC-PUFA), such as Eicosapentaenoic Acid and Docosapentaenoic Acid, n-3/n-6 ratio and triene/tetraene ratio were higher in patients with type 2 diabetes (t2dm) compared with LADA and t1dm. Saturated FAs were lower in t2dm than t1dm and LADA. Arachidic acid and n-6 LC-PUFAs were lower in t2dm than in t1dm and LADA. The characteristics of FAs in LADA were in between of classical t1dm and t2dm. Patients were classified into 6 clusters by FA clusters. Only cluster 2, 3, 5 contained enough patients to be analyzed. Cluster 5 showed an insulin deficient phenotype containing more than 60% of patients with t1dm and LADA and only 12.8% of t2dm. Cluster 2 and 3 were similar. β cell function and glycemic control was better in cluster 3 homing 25% of t2dm. Cluster 2 held 28% of t1dm and LADA, in this cluster more than 60% of patients was t2dm. n-3 linolenic acid, n-3 LC-PUFAs, some n-6 LC-PUFAs, n-3/n-6 ratio and triene/tetraene ratio were negatively associated with GADA positivity while n-6 Arachidonic Acid was associated positively with GADA. Similar findings were found for insulin sensitivity and beta cell function.

CONCLUSION

PUFA are associated with insulin sensitivity and beta cell function, and like other clinical features, FA profile distributed differently, but could not be used as makers to differentiate LADA from t1dm and t2dm.

ETHICS AND DISSEMINATION

This study has been approved by the Ethical Review Committee of Second Hospital of Dalian Medical University (approval number: 2021-005).

CLINICAL TRIAL REGISTRATION

none.

Combination of vitamin D and dipeptidyl peptidase-4 inhibitors (VIDPP-4i) as an immunomodulation therapy for autoimmune diabetes

Type 1 diabetes (T1D) and latent autoimmune diabetes in adults (LADA) represent the most common types of autoimmune diabetes and are characterized by different age of onset, degrees of immune-mediated destruction of pancreatic beta cells and rates of disease progression towards insulin dependence. Several immunotherapies aimed to counteract autoimmune responses against beta cells and preserve beta-cell function are currently being investigated, particularly in T1D. Preliminary findings suggest a potential role of combination therapy with vitamin D and dipeptidyl peptidase-4 (DPP-4) inhibitors (VIDPP-4i) in preserving beta-cell function in autoimmune diabetes. This manuscript aims to provide a comprehensive overview of the immunomodulatory properties of vitamin D and DPP-4 inhibitors, as well as the rationale for investigation of their combined use as an immunomodulation therapy for autoimmune diabetes.

From immunohistological to anatomical alterations of human pancreas in type 1 diabetes: New concepts on the stage

The histological analysis of human pancreatic samples in type 1 diabetes (T1D) has been proven essential to move forward in the evaluation of in situ events characterizing T1D. Increasing availability of pancreatic tissues collected from diabetic multiorgan donors by centralized biorepositories, which have shared tissues among researchers in the field, has allowed a deeper understanding of T1D pathophysiology, using novel immunohistological and high-throughput methods. In this review, we provide a comprehensive update of the main recent advancements in the characterization of cellular and molecular events involving endocrine and exocrine pancreas as well as the immune system in the onset and progression of T1D. Additionally, we underline novel elements, which provide evidence that T1D pathological changes affect not only islet β-cells but also the entire pancreas.

Standard mortality rates and years of life lost for serologically defined adult-onset type 1 and type 2 diabetes - A fifteen year follow-up

AIMS

The Diabetes Incidence in Kronoberg (DIK) study of adult-onset diabetes used serological classification. Standard Mortality Rates (SMR) and Years of Life Lost (YLL) 15 years after adult-onset (18-100 years) of diabetes were compared to the population of Kronoberg.

METHODS

Of 1609/1660 (97%) patients, 112 (7%) had type 1 (T1D) (GADA⁺ and/or ICA⁺, and/or C-peptide < 0.25 nmol/l), and 1497 (93%) had type 2 diabetes (T2D) (antibody^- and C-peptide ≥ 0.25 nmol/l). The National Swedish Mortality Register provided time of death.

RESULTS

For T1D SMR did not differ from the Kronoberg population in any age group. In T2D SMR was 1.20 (1.12-1.29). After 15 years 26% (29/112) T1D and 52% (785/1497) T2D patients had died, p < 0.0001. In T2D SMR was 5.6 (30-39 years), 2 (40-59 years), 1.4 (60-69 years), and thereafter no difference. There were no significant sex differences in mortality, and no YLL to adult-onset T1D, but five YLL to T2D for onset at ages 20-60 years.

CONCLUSIONS

For adult-onset T1D SMR did not differ from the general population, in contrast to previous findings in childhood-onset (< 30 years of age) T1D. The difference in mortality between persons with diabetes and the general population was due to higher mortality in T2D.

Distinct two different ages associated with clinical profiles of acute onset type 1 diabetes in Chinese patients

BACKGROUND

There are abundant variations in the phenotypes and genetics of type 1 diabetes (T1D) patients across different races. This study aimed to assess differences between juvenile acute onset (JAO) and adult acute onset in Chinese T1D patients.

METHODS

Seven hundred and fifty-one acute onset T1D patients were divided into two groups by the patient onset age as follows: the juvenile acute onset group (≤20 years, JAO group) and the adult acute onset group (>20 years, AAO group). Clinical characteristics, islet autoantibodies, and HLA class II haplotypes and genotypes were compared between these two groups.

RESULTS

In comparison with AAO patients, JAO patients had significantly lower relative weights and lower triglyceride levels (P < .001, P < .01, respectively) but higher frequency of ketoacidosis (P < .001), higher daily insulin dosage (P_c  < .001), higher HbA1_c (P_c  < .05), and higher HDL-cholesterol levels (P_c  < .01). The JAO group showed a higher prevalence of IA-2A, ZnT8A, and multiple autoantibodies than that in the AAO group (P < .001, P < .01, P < .001, respectively). Haplotypes for DRB1*0301-DQA1*03-DQB1*0201, DR3, DR4, DR9, and DR3/DR9 genotypes are highly associated with JAO susceptibility, whereas only DR3 and DR9 genotypes confer risk for AAO. In the JAO group but not the AAO group, DR3 is related to ZnT8A, and DR3/DR9 is related to IA-2A and multiple autoantibodies.

CONCLUSIONS

These observations suggest that JAO patients markedly differ from AAO patients in their clinical manifestations and genetics in the Chinese T1D population. Notably, the DR3/DR9 genotype can facilitate the appearance of IA-2A or multiple autoantibodies in JAO patients.

The Challenges of Identifying Environmental Determinants of Type 1 Diabetes: In Search of the Holy Grail

Type 1 diabetes is the result of autoimmune-mediated destruction and inflammation of the insulin-producing β-cells of the pancreas. The excess morbidity and mortality from its complications coupled with its increasing incidence emphasize the importance to better understand the etiology of this condition. It has a strong genetic component, but a genetic predisposition is not the sole contributor to disease development as only 30% to 50% of identical twins both develop the disease. In addition, there are multiple lines of evidence to support that environmental factors contribute to the pathogenesis of type 1 diabetes. Environmental risk factors that have been proposed include infections, dietary factors, air pollution, vaccines, location of residence, childhood obesity, family environment and stress. Researchers have conducted many observational studies to identify and characterize these potential environmental factors, but findings have been inconsistent or inconclusive. Many studies have had inherent methodological issues in recruitment, participation, defining cases and exposures, and/or data analysis which may limit the interpretability of findings. Identifying and addressing these limitations may allow for greatly needed advances in our understanding of type 1 diabetes. As such, the purpose of this article is to review and discuss the limitations of observational studies that aim to determine environmental risk factors for type 1 diabetes and propose recommendations to overcome them.

Adult-onset autoimmune diabetes: current knowledge and implications for management

Adult-onset autoimmune diabetes is a heterogeneous disease that is characterized by a reduced genetic load, a less intensive autoimmune process and a mild metabolic decompensation at onset compared with young-onset type 1 diabetes mellitus (T1DM). The majority of patients with adult-onset autoimmune diabetes do not require insulin treatment for at least 6 months after diagnosis. Such patients are defined as having latent autoimmune diabetes in adults (LADA), which is distinct from classic adult-onset T1DM. The extensive heterogeneity of adult-onset autoimmune diabetes is apparent beyond the distinction between classic adult-onset T1DM and LADA. LADA is characterized by genetic, phenotypic and humoral heterogeneity, encompassing different degrees of insulin resistance and autoimmunity; this heterogeneity is probably a result of different pathological mechanisms, which have implications for treatment. The existence of heterogeneous phenotypes in LADA makes it difficult to establish an a priori treatment algorithm, and therefore, a personalized medicine approach is required. In this Review, we discuss the current understanding and gaps in knowledge regarding the pathophysiology and clinical features of adult-onset autoimmune diabetes and highlight the similarities and differences with classic T1DM and type 2 diabetes mellitus.

Comparison of Metabolic Outcomes in Children Diagnosed with Type 1 Diabetes Through Research Screening (Diabetes Autoimmunity Study in the Young [DAISY]) Versus in the Community

BACKGROUND

Children with positive islet autoantibodies monitored prospectively avoid metabolic decompensation at type 1 diabetes (T1D) diagnosis. However, the effects of early diagnosis and treatment on preservation of insulin secretion and long-term metabolic control are unknown. We compared characteristics of children detected through research screening (Diabetes Autoimmunity Study in the Young [DAISY]) versus community controls at baseline and, in a subset, 6- and 12-month metabolic outcomes.

MATERIALS AND METHODS

This was a case-control study comparing DAISY children with T1D to children diagnosed in the general community. All participants underwent mixed-meal tolerance testing; a subset wore a continuous glucose monitoring (CGM) device. Fasting and stimulated C-peptide levels, insulin dose-adjusted hemoglobin A1c (IDAA1c), and CGM variables were compared.

RESULTS

Children (21 DAISY, 21 community) were enrolled and matched by age, time of diagnosis, and diabetes duration; 18 were enrolled within 2 months and 24 within 2.5 years on average from diagnosis. In the overall group and the subgroup of participants enrolled 2.5 years from diagnosis, there were no IDAA1c or C-peptide differences between DAISY versus community children. The subgroup of DAISY versus community children enrolled near diagnosis, however, had lower baseline hemoglobin A1c (6.5±1.4% vs. 9.2±2.9%; P=0.0007) and IDAA1c (7.4±2.1% vs. 11.2±3.5%; P=0.04) and higher stimulated C-peptide (2.5±0.5 vs. 1.6±0.2 ng/mL; P=0.02). In this subgroup, IDAA1c differences persisted at 6 months but not at 1 year. CGM analyses revealed lower minimum overnight glycemia in community children (72 vs. 119 mg/dL; P=0.01).

CONCLUSIONS

Favorable patterns of IDAA1c and C-peptide seen in research-screened versus community-diagnosed children with T1D within 2 months of diagnosis are no longer apparent 1 year from diagnosis.

Combination immunotherapies for type 1 diabetes mellitus

Immunotherapies for type 1 diabetes mellitus (T1DM) have been the focus of intense basic and clinical research over the past few decades. Restoring β-cell function is the ultimate goal of intervention trials that target the immune system in T1DM. In an attempt to achieve this aim, different combination therapies have been proposed over the past few years that are based on treatments tackling the various mechanisms involved in the destruction of β cells. The results of clinical trials have not matched expectations based on the positive results from preclinical studies. The heterogeneity of T1DM might explain the negative results obtained, but previous trials have not addressed this issue. However, novel promising combination therapies are being developed, including those that couple immunomodulators with drugs that stimulate β-cell regeneration in order to restore normoglycaemia. This strategy is an encouraging one to pursue the goal of finding a cure for T1DM. This Review summarizes the available data about combination immunotherapies in T1DM, particularly addressing their clinical importance. The available data supporting the use of registered drugs, such as proton pump inhibitors and incretin-based agents, that have been shown to induce β-cell regeneration will also be discussed.

Assessing age-related etiologic heterogeneity in the onset of islet autoimmunity

Type 1 diabetes (T1D), a chronic autoimmune disease, is often preceded by a preclinical phase of islet autoimmunity (IA) where the insulin-producing beta cells of the pancreas are destroyed and circulating autoantibodies can be detected. The goal of this study was to demonstrate methods for identifying exposures that differentially influence the disease process at certain ages by assessing age-related heterogeneity. The Diabetes Autoimmunity Study in the Young (DAISY) has followed 2,547 children at increased genetic risk for T1D from birth since 1993 in Denver, Colorado, 188 of whom developed IA. Using the DAISY population, we evaluated putative determinants of IA, including non-Hispanic white (NHW) ethnicity, maternal age at birth, and erythrocyte membrane n-3 fatty acid (FA) levels, for age-related heterogeneity. A supremum test, weighted Schoenfeld residuals, and restricted cubic splines were used to assess nonproportional hazards, that is, an age-related association of the exposure with IA risk. NHW ethnicity, maternal age, and erythrocyte membrane n-3 FA levels demonstrated a significant age-related association with IA risk. Assessing heterogeneity in disease etiology enables researchers to identify associations that may lead to better understanding of complex chronic diseases.

The association between the serum C-peptide level and bone mineral density

Objective

Although serum C-peptide was previously considered biologically inactive, a growing number of recent studies have shown that it is an active peptide with important physiologic functions. The present study aimed to investigate the association of serum C-peptide level with bone mineral density (BMD) in residents of the United States.

Methods

The study included 6,625 participants aged 12–85 years. Total and regional BMD were measured using dual-energy X-ray absorptiometry. Stratified multiple linear regression analysis was performed to determine the association of the serum C-peptide level with BMD. Three regression models were produced for each stratum. All models were adjusted for ethnicity, height, weight, education level, physical activity, smoking status, alcohol use, triglycerides and creatinine level, and models 2 and 3 were further adjusted for the fasting plasma glucose (FPG) and alkaline phosphatase (ALP) levels, respectively.

Results

Sex-specific results showed a significant association between the serum C-peptide level and total BMD in both sexes. Stratified analyses based on age and body mass index showed that serum C-peptide levels were significantly negatively associated with most regional BMD, and most of these associations remained significant after stratification based on the serum insulin level.

Conclusion

The serum C-peptide level was significantly negatively associated with the total and most regional BMD. These findings suggest that serum C-peptide may have biological activity associated with bone metabolism and therefore serum C-peptide control is advisable in order to reduce the risk of low bone mineral density.

Temporal trends of HLA, CTLA-4 and PTPN22 genotype frequencies among type 1 diabetes in Continental Italy

The incidence of type 1 diabetes has, progressively, increased worldwide over the last decades and also in Continental Italian population. Previous studies performed in northern European countries, showed, alongside a general increase in the disease incidence, a decreasing frequency of the highest risk HLA genotype in type 1 diabetes populations, thus emphasizing the role of environmental factors. The aim of the study was to evaluate whether a decreasing trend of high risk HLA, CTLA-4 and PTPN22 genotypes would be present in type 1 diabetes subjects of Continental Italy, a country considered at low incidence of the disease compared to northern European populations. N = 765 type 1 diabetes patients diagnosed from 1980 to 2012 in Lazio region were included. For HLA, CTLA4 and PTPN22 temporal trend evaluation, subjects were subdivided into groups of years according to age at diagnosis. All subjects were typed for HLA-DRB1 and DQB1 by a reverse line blot. The CT60 polymorphism of the CTLA4 and C1858T of the PTPN22 gene were genotyped using ABI PRISM 7900HT (n = 419 and n = 364 respectively). HLA genotypes were divided in high, moderate and low risk categories. The proportion of the HLA risk categories was not statistically different over the three decades in subjects with age of onset <15 years and ≥ 15 years. The genotype distribution of CT60 polymorphism of CTLA4 gene did not show any change in the frequencies during time. The analysis of the PTPN22 C1858T variant revealed, instead, that the frequency of CT+TT susceptibility genotypes decreased during time (23.9% vs 13.6%, p = 0.017). We can hypothesize that the pressure of the diabetogenic environment could be milder and therefore not sufficient to reduce the need of a strong genetic background (HLA) "to precipitate" diabetes; the increased pressure of the environment could have, instead, some effects on minor susceptibility genes in our population.

Influence of type 1 diabetes genes on disease progression: similarities and differences between countries

Type 1 diabetes (T1D) is an autoimmune disease causing the destruction of pancreatic beta cells. The onset of clinical T1D is preceded by a time period called pre-diabetes, the duration of which varies widely. However, not all subjects developing beta-cell autoimmunity progress to clinical T1D. The inherited risk for T1D is determined by the human leukocyte antigen (HLA) class II genes, HLA class I genes, and several loci outside the HLA area. Although the role of the genetic risk variants in disease pathogenesis is not completely understood, some of the variants affecting disease risk are thought to influence the initiation of beta-cell autoimmunity whereas others seem to play a role during the later stages of the autoimmune process. In this review we describe the current knowledge on the genetic factors mediating the fate of already-established beta-cell autoimmunity and the rate of beta-cell destruction.

Fall in C-peptide during first 2 years from diagnosis: evidence of at least two distinct phases from composite Type 1 Diabetes TrialNet data

Interpretation of clinical trials to alter the decline in β-cell function after diagnosis of type 1 diabetes depends on a robust understanding of the natural history of disease. Combining data from the Type 1 Diabetes TrialNet studies, we describe the natural history of β-cell function from shortly after diagnosis through 2 years post study randomization, assess the degree of variability between patients, and investigate factors that may be related to C-peptide preservation or loss. We found that 93% of individuals have detectable C-peptide 2 years from diagnosis. In 11% of subjects, there was no significant fall from baseline by 2 years. There was a biphasic decline in C-peptide; the C-peptide slope was -0.0245 pmol/mL/month (95% CI -0.0271 to -0.0215) through the first 12 months and -0.0079 (-0.0113 to -0.0050) from 12 to 24 months (P < 0.001). This pattern of fall in C-peptide over time has implications for understanding trial results in which effects of therapy are most pronounced early and raises the possibility that there are time-dependent differences in pathophysiology. The robust data on the C-peptide obtained under clinical trial conditions should be used in planning and interpretation of clinical trials.

Levels of C-peptide, body mass index and age, and their usefulness in classification of diabetes in relation to autoimmunity, in adults with newly diagnosed diabetes in Kronoberg, Sweden

OBJECTIVE

C-peptide is a main outcome measure in treatment trials of diabetes. C-peptide also has a role in the classification of diabetes, which is often difficult in adults and this is also increasingly recognised in adolescents and elders.

AIM

We aimed to describe the levels of C-peptide in relation to age and body mass index (BMI) in a large population-based cohort of adults with newly diagnosed diabetes and compare the capabilities of C-peptide, age and BMI to discriminate between autoimmune and non-autoimmune diabetes.

SUBJECTS AND METHODS

Blood samples from 1180 patients were analysed regarding islet cell antibody, glutamic acid decarboxylase antibody and fasting C-peptide (FCP). Receiver operating characteristics (ROC) curves were analysed to check the ability of age, BMI and C-peptide to discriminate between autoantibody-positive (Ab(+)) and -negative (Ab(-)) diabetes.

RESULTS

Mean FCP was 0.73±0.5 (range 0.13-1.80) nmol/l in the Ab(+) and 1.42±0.9 (range 0.13-8.30) nmol/l in the Ab(-). FCP was 0.02 nmol/l higher per year increase in age at diagnosis of diabetes. Mean BMI was 26.0±4.8 (range 18.0-39.0) kg/m(2) in the Ab(+) and 28.9±5.3 (range 15.5-62.6) kg/m(2) in the Ab(-). FCP increased with age also within each BMI group. The highest area under the curve (AUC) in the ROC analysis was found for C-peptide, followed by age and BMI (0.78, 0.68 and 0.66 respectively).

CONCLUSIONS

At diagnosis of diabetes, C-peptide was superior to age and BMI in discriminating between autoimmune and non-autoimmune diabetes. C-peptide increased significantly with BMI and age, latter also within each BMI group. Most of the adults had normal or high levels of C-peptide at presentation of diabetes among the autoimmune patients.

C-peptide response and HLA genotypes in subjects with recent-onset type 1 diabetes after immunotherapy with DiaPep277: an exploratory study

OBJECTIVE

To investigate whether lower risk HLA class II genotypes would influence the efficacy of DiaPep277 therapy in protecting β-cell function evaluated by C-peptide secretion in recent-onset type 1 diabetic subjects.

RESEARCH DESIGN AND METHODS

Data were collected from type 1 diabetic subjects enrolled in multicenter phase II studies with a randomized, double-blind, and placebo-controlled design in whom fasting and stimulated C-peptide levels were measured. HLA genotypes were classified in high, moderate, and low risk categories.

RESULTS

A total of 146 subjects (aged 4.3 to 58.5 years) were enrolled, including 76 children (<18 years old) and 70 adults. At baseline, there was a significant increase in fasting, maximal, and area under the curve (AUC) C-peptide from high to moderate and low risk HLA genotypes in adults (P for trend <0.04) but not in children. Children showed a decrease of the three parameters over time regardless of therapy and HLA genotype. DiaPep277-treated adults with low risk genotype had significantly higher maximal and AUC C-peptide versus placebo at 12 months (0.04 ± 0.07 vs. -0.28 ± 0.09 nmol/L, P < 0.01, and 0.53 ± 1.3 vs. -4.59 ± 1.5 nmol/L, P < 0.05, respectively). In the moderate risk genotype group, Δmaximal and AUC C-peptide values were significantly higher in DiaPep277-treated versus placebo-treated patients (P < 0.01 and P < 0.05, respectively).

CONCLUSIONS

This exploratory study demonstrates that type 1 diabetic adults with low and moderate risk HLA genotypes benefit the most from intervention with DiaPep277; the only subgroup with an increase of C-peptide at 12 months after diagnosis was the low risk DiaPep277-treated subgroup.

Clinical presentation and autoimmune characteristics of very young children at the onset of type 1 diabetes mellitus

The aim of our study was to identify factors that are related to a more aggressive beta-cell destruction in children at presentation of type 1 diabetes mellitus (T1D). We analyzed age, HbAlc, pH, bicarbonate, IAA, IA2, GADA, C peptide of 290 consecutive patients with T1D at onset. Seventy-three (25.2%) were younger than 4 years; 217 (74.8%) were aged 4-18 years. Younger patients had lower C peptide, pH and bicarbonate than older ones. Age at T1D onset was negatively related to IAA titers (r: -0.3404, p < 0.001), positively related to IA2 titers (r: 0.1249, p: 0.03) and to C peptide (r: 0.42, p: < 0.001). Multivariable linear regression showed that C peptide was negatively related to HbA1c and positively related to age, pH at admission and IAA titers. T1D in very young children is characterized by a more extensive beta-cell destruction, and younger age at onset is related to a more severe decompensation.

Dendritic cell-based therapy in Type 1 diabetes mellitus

Dendritic cell (DC) immunotherapy is a clinical reality. Despite two decades of considerable data demonstrating the feasibility of using DCs to prolong transplant allograft survival and to prevent autoimmunity, only now are these cells entering clinical trials in humans. Type 1 diabetes is the first autoimmune disorder to be targeted for treatment in humans using autologous-engineered DCs. This review will highlight the role of DCs in autoimmunity and the manner in which they have been engineered to treat these disorders in rodent models, either via the induction of immune hyporesponsiveness, which may be cell- and/or antigen-specific, or indirectly by upregulation of other immune cell networks.

Autologous stem cell transplantation for early type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) is the result of the autoimmune response against pancreatic insulin producing beta cells. This autoimmune response begins months or even years before the first presentation of signs and symptoms of hyperglycemia and at the time of clinical diagnosis near 30% of beta-cell mass still remains. In daily clinical practice, the main therapeutic option for T1DM is multiple subcutaneous insulin injections that are shown to promote tight glucose control and reduce much of diabetic chronic complications, especially microvascular complications. Another important aspect related to long-term complications of diabetes is that patients with initially larger beta-cell mass suffer less microvascular complications and less hypoglycemic events than those patients with small beta-cell mass. In face of this, beta-cell preservation is another important target in the management of type 1 diabetes and its related complications. For many years, various immunomodulatory regimens were tested aiming at blocking autoimmunity against beta-cell mass and at promoting beta-cell preservation, mainly in secondary prevention trials. In this review, we summarize some of the most important studies involving beta-cell preservation by immunomodulation and discuss our preliminary data on autologous nonmyeloablative hematopoietic stem cell transplantation in newly-diagnosed T1DM.

Challenges in developing endpoints for type 1 diabetes intervention studies

Development of efficient and safe intervention strategies for preserving and/or restoring endogenous insulin production in type 1 diabetes has encountered a wide range of challenges, including lack of standardized trial protocols and of consensus on appropriate efficacy endpoints. For the greatest part, difficulties resided in choosing the most suitable assay(s) and parameter(s) to assess the beta-cell function. It is now an accepted approach to evaluate endogenous insulin secretion by measuring C-peptide levels (with highly sensitive and normalized measurement methods) in response to a physiologic stimulus (liquid mixed-meal) under standardized conditions. Preventive interventions mandate the identification of well-defined, reliable and validated mechanistic or immunological markers of efficacy that would correlate with (and predict) the clinical outcome. This has not been consistently achieved to date. However, it has been generally agreed that for preventive studies performed very early in the disease course (in subjects without signs of autoimmunity against beta-cells) development of two or more islet related autoantibodies could be employed as biomarkers of disease and thereafter, diagnostic criteria of diabetes serve as suitable endpoints.This report summarizes the conclusions of the D-Cure workshop of international experts held in Barcelona in April 2007 and the current recommendations and updates in the field.

C-peptide in the natural history of type 1 diabetes

Type 1 diabetes is diagnosed when the patient's endogenous insulin secretion decreases to a level which results in hyperglycemia. After diagnosis, insulin secretion continues to decline. As a reference for clinical trials trying to preserve endogenous beta-cell function in patients with recently diagnosed type 1 diabetes, in this short review I attempt to summarize the natural history of endogenous beta-cell function after the diagnosis of type 1 diabetes.

Potential role of stem cell therapy in type 1 diabetes mellitus

Type 1 diabetes mellitus is the result of the autoimmune response against pancreatic beta-cell(s). At the time of clinical diagnosis near 70% of beta-cell mass is been destroyed as a consequence of the auto-destruction that begins months or even years before the clinical diagnosis. Although marked reduction of chronic complications was seen after development and progression of insulin therapy over the years for type 1 diabetic population, associated risks of chronic end-organ damage and hypoglycemia still remain. Besides tight glucose control, beta-cell mass preservation and/or increase are known to be other important targets in management of type 1 diabetes as long as it reduces chronic microvascular complications in the eyes, kidneys and nerves. Moreover, the larger the beta-cell mass, the lower the incidence of hypoglycemic events. In this article, we discuss some insights about beta-cell regeneration, the importance of regulation of the autoimmune process and what is being employed in human type 1 diabetes in regard to stem cell repertoire to promote regeneration and/or preservation of beta-cell mass.

Autoimmune diabetes in adults: lessons from the UKPDS

Latent autoimmune diabetes in adults (LADA) is characterised by a relatively mild diabetes onset, autoantibody positivity and eventual requirement for insulin therapy. Twelve per cent of newly diagnosed, UK Prospective Diabetes Study (UKPDS) patients were positive for autoantibodies to GAD65 (GADA) and/or insulinoma-associated antigen-2A (IA-2A) and managed as if they had Type 2 diabetes according to the UKPDS protocol. Here, we compare data from UKPDS LADA patients with that from other cohorts. In common with other groups, UKPDS LADA patients required insulin therapy earlier post-diagnosis than non-LADA patients. Reduction of islet function was similar in UKPDS LADA groups randomised to oral glucose-lowering agents or insulin replacement therapy, contesting the current hypothesis of reduced decline of insulin secretion in LADA by immediate insulin therapy. Disease progression was not predicted by post-diagnosis GADA levels or epitope specificities as has been suggested. Slowly progressing insulitis and pancreatic beta-cell loss at post-mortem are consistent with sustained retention of residual C-peptide secretion in LADA. Genetic association patterns at the human leucocyte antigen (HLA) and insulin gene (INS) regions are similar in UKPDS LADA patients and individuals with adult and childhood-onset Type 1 diabetes. The combined evidence suggests that LADA is an adult-onset form of Type 1 diabetes, rather than a separate condition or an intermediate state in a continuum of phenotype from Type 1 to Type 2 diabetes.

Age at diagnosis, gender, and metabolic control in children with type 1 diabetes

OBJECTIVE

To examine whether age at diagnosis and gender affect early metabolic control in children with type 1 diabetes.

DESIGN AND METHODS

Data on age at diagnosis, gender, pubertal status, and metabolic control were gathered by a retrospective chart review of children diagnosed between 1992 and 2005. Mean hemoglobin A1c (HbA1c) values were compared at five time points: at diagnosis and at 6, 12, 24, and 36 months after diagnosis.

RESULTS

At diagnosis, girls aged 6-12 years presented with significantly higher HbA1c levels than girls diagnosed at older or younger ages. Their HbA1c at diagnosis was also significantly higher than that in boys of the same age. There was no gender difference among children diagnosed at ages 0-5 or 13+ yr. At 6 months after diagnosis, only age at diagnosis was associated with metabolic control, with children diagnosed when older presenting with lower HbA1c levels. At 12, 24, and 36 months after diagnosis, there were no significant effects of age at diagnosis or gender on glycemic status.

CONCLUSION

At initial diagnosis, girls in the 6-12 age group presented with higher HbA1c levels compared with boys and girls of other age groups. Although endocrine changes associated with puberty may partly explain the findings, more investigation to elucidate mechanisms accounting for the interaction of age and gender with glycemic status is needed.

The PTPN22 1858T gene variant in type 1 diabetes is associated with reduced residual beta-cell function and worse metabolic control

OBJECTIVE

Evidence has been reported for a new susceptible locus for type 1 diabetes, the protein tyrosine phosphatase nonreceptor type 2 (PTPN22), which encodes a lymphoid-specific phosphatase. The aim of the study was to evaluate the influence of the C1858T variant of the PTPN22 gene on beta-cell function as measured by C-peptide levels from time of disease diagnosis through 12 months follow-up in a prospective series of 120 consecutive type 1 diabetic subjects.

RESEARCH DESIGN AND METHODS

The C1858T polymorphism was genotyped using TaqMan. Fasting C-peptide, A1C, and insulin requirements were determined at diagnosis and every 3 months for 12 months; their change during follow-up was analyzed using the general linear model repeated-measures procedure.

RESULTS

Fasting C-peptide levels were significantly lower and A1C levels were significantly higher in subjects carrying the PTPN22 1858T variant than in subjects homozygous for C1858 from time of disease diagnosis through 12 months of intensive insulin therapy follow-up (P = 0.008 and P = 0.01, respectively). These findings were independent of age at onset, sex, and HLA risk groups. The trend in C-peptide and A1C levels in the 12-month period did not differ significantly between subjects with or without the 1858T variant. Insulin dose was similar in the 1858T carriers and noncarriers.

CONCLUSIONS

Type 1 diabetic subjects carrying the 1858T variant show significantly lower beta-cell function and worse metabolic control at diagnosis and throughout the study period than subjects homozygous for C1858; these differences remain unchanged over the course of the first year after diagnosis.

Low-risk HLA genotype in Type 1 diabetes is associated with less destruction of pancreatic B-cells 12 months after diagnosis

AIMS

The role of human leukocyte antigen (HLA) genes in the susceptibility to Type 1 diabetes (T1DM) is well known. However, we do not know whether the degree of pancreatic B-cell destruction depends on different HLA genetic risk. The aim of this study was to analyse the influence of DRB1* and DQB1* genes on the rate of pancreatic B-cell loss in a prospective series of 120 consecutive newly diagnosed T1DM subjects in the first 12 months after diagnosis.

METHODS

Patients were typed for HLA-DRB1* and DQB1* loci by a reverse line blot assay using an array of immobilized sequence-specific oligonucleotide probes. C-peptide, insulin requirement and glycated haemoglobin (HbA(1c)) were determined at diagnosis and every 3 months for 12 months. The variance of C-peptide as evidence of B-cell loss during follow-up was analysed using the general linear model for repeated-measures procedure.

RESULTS

Fasting C-peptide in T1DM subjects with low HLA genetic risk was significantly higher when compared with subjects with moderate or high HLA genetic risk from time of diagnosis up to 12 months (P = 0.007 and P = 0.0002, respectively). Nonetheless, the changes in C-peptide levels over a 12-month period did not differ significantly between T1DM subjects with different HLA genetic risks.

CONCLUSIONS

Low-risk HLA genotype in T1DM is associated with less destruction of pancreatic B-cells up to 12 months after diagnosis. These results are useful when designing trials for therapies aimed to prevent the progression of B-cell destruction in recent-onset T1DM.

Immunoregulatory dendritic cells to prevent and reverse new-onset Type 1 diabetes mellitus

Herein, the authors provide an overview of where dendritic cells lie in the immunopathology of autoimmune Type 1 diabetes mellitus and how dendritic cell-based therapy may be usefully translated to treat and reverse the disease. The immunopathology of Type 1 diabetes mellitus offers a number of windows at which immunotherapy can be applied to delay, stop and even reverse the autoimmune processes, especially in light of the recent antibody-based accomplishment of improvement in residual beta-cell mass function. As in almost all cell-specific inflammatory processes, dendritic cells are central regulators of diabetes onset and progression. This realisation, along with accumulating data confirming a role for dendritic cells in maintaining and inducing tolerance in multiple therapeutic settings, has prompted a line of investigation to identify the most effective embodiments of dendritic cells for diabetes immunotherapy.

Treatment of new-onset type 1 diabetes with peptide DiaPep277 is safe and associated with preserved beta-cell function: extension of a randomized, double-blind, phase II trial

BACKGROUND

Treatment with DiaPep277, a peptide derived from HSP60, has been shown to preserve beta-cell function in non-obese diabetic mouse (NOD) mice and in a trial with newly diagnosed human patients with type 1 diabetes treated over a 10-month period. This article extends the clinical trial observations to a total of 20 months of treatment to determine the safety and the effects of repeated doses of DiaPep277 on endogenous insulin secretion, metabolic control, and exogenous insulin requirements.

METHODS

Thirty-five male patients (aged 16-58) with a basal C-peptide greater than 0.1 nmol/L were assigned to periodic treatment with DiaPep277 (1 mg) or placebo for a 12-month treatment and 18-month observation protocol, later extended to an additional year of treatment. Stimulated C-peptide, HbA1c, and an exogenous insulin dose were the clinical endpoints.

RESULTS

At 18 months, stimulated C-peptide concentrations had fallen in the placebo group (p = 0.0005) but were maintained in the DiaPep277 group. The need for exogenous insulin was higher in the placebo group than in the DiaPep277 group. Mean HbA1c concentrations were similar in both groups. After extension of the study, patients continuing treatment with DiaPep277 and those switched from placebo to DiaPep277 manifested a trend towards a greater preservation of beta-cell function compared to patients maintained on or switched to placebo. The safety profile of DiaPep277 was similar between the treatment and placebo groups, and no drug-related adverse events occurred.

CONCLUSIONS

Periodic treatment of subjects with DiaPep277 over 2 years was safe and associated preservation of endogenous insulin secretion up to 18 months was observed.

Effect of heat shock protein peptide DiaPep277 on beta-cell function in paediatric and adult patients with recent-onset diabetes mellitus type 1: two prospective, randomized, double-blind phase II trials

BACKGROUND

Aim of this trial was to test whether heat shock protein peptide DiaPep277 treatment in adult and paediatric patients with recent-onset type 1 diabetes (T1D) is safe and whether it can preserve endogenous insulin production.

METHODS

Two studies were performed in a prospective, multicentre, double-blind, placebo-controlled trial. Fifty adult (study p520, aged 16-44 years) and 49 paediatric patients (study p521, 4-15 years) with recent-onset T1D were treated subcutaneously at four different time points with 0.2 mg or 1.0 mg DiaPep277 versus placebo and followed for 18 months. Adult patients were treated with 0.2 mg, 1.0 mg or 2.5 mg DiaPep277 versus placebo. Stimulated C-peptide served as readout for functional beta-cell-mass.

RESULTS

DiaPep277-treatment was not associated with severe side effects. No differences were found in placebo and DiaPep277 treated groups. In adults, a modest trend towards better maintenance of beta-cell function was observed in the 0.2 mg and 1.0 mg group, while there was significant loss of stimulated C-peptide in the placebo and 2.5 mg group. Paediatric patients with low HLA risk showed stable C-peptide levels until 13 months upon treatment with 1 mg DiaPep277. Despite similar stimulated C-peptide levels at baseline, children exhibited a more pronounced loss of beta-cell function over 18 months than adults (p = 0.0003).

CONCLUSION

Administration of DiaPep277 seems safe and may have beneficial effects on C-peptide levels over time in some patients with T1D, but this finding was not accompanied by reduced HbA1c or insulin requirement. Studies with more patients and longer follow-up are needed to further study the effect of DiaPep277.

Temporary diabetes mellitus secondary to a primary pancreatic Burkitt lymphoma

Primary pancreatic lymphoma (PPL) is a rare form of extranodal lymphoma. So far, only in adults has a coincidence with diabetes mellitus (DM) been described. We report a nearly 9-year-old German boy presenting with a Burkitt lymphoma associated with a temporary insulin-dependent DM and exocrine insufficiency of the pancreas. After the patient went into remission, a spontaneous recovery of the endocrine pancreatic function was observed. On immunophenotyping, the lymphoma cells revealed expression of FasL suggesting a potentially apoptotic effect on pancreatic tissue. Beta cell impairment may have been caused by FasL resembling autoimmune diabetes.