Diabetes: 1 and 2, or one and the same? Progress with the accelerator hypothesis

Glucose-Lowering Therapy beyond Insulin in Type 1 Diabetes: A Narrative Review on Existing Evidence from Randomized Controlled Trials and Clinical Perspective

Background: In Type 1 diabetes (T1D), according to the most recent guidelines, the everyday glucose-lowering treatment is still restricted to the use of subcutaneous insulin, while multiple therapeutic options exist for Type 2 diabetes (T2D). Methods: For this narrative review we unsystematically screened PubMed and Embase to identify clinical trials which investigated glucose-lowering agents as an adjunct to insulin treatment in people with T1D. Published studies up to March 2022 were included. We discuss the safety and efficacy in modifying cardiovascular risk factors for each drug, the current status of research, and provide a clinical perspective. Results: For several adjunct agents, in T1D, the scientific evidence demonstrates improvements in HbA1c, reductions in the risk of hypoglycemia, and achievements of lower insulin requirements, as well as positive effects on cardiovascular risk factors, such as blood lipids, blood pressure, and weight. As the prevalence of obesity, the major driver for double diabetes, is rising, weight and cardiovascular risk factor management is becoming increasingly important in people with T1D. Conclusions: Adjunct glucose-lowering agents, intended to be used in T2D, bear the potential to beneficially impact on cardiovascular risk factors when investigated in the T1D population and are suggested to be more extensively considered as potentially disease-modifying drugs in the future and should be investigated for hard cardiovascular endpoints.

Increased Incidence of Type 1 Diabetes in Children and No Change in the Age of Diagnosis and BMI-SDS at the Onset - is the Accelerator Hypothesis not Working?

OBJECTIVE

One of the hypothesized reasons for the observed increase in type 1 diabetes incidence in children is weight gain, causing accelerated disease development in predisposed individuals. This so-called accelerator hypothesis is, however, controversial. The aim was to analyze whether, in the ethnically homogeneous population of Lesser Poland, an increase in the number of cases of diabetes among children was associated with younger age and higher body mass index-standard deviation score (BMI-SDS) at the time of diagnosis.

METHODS

Retrospective data analysis from medical records of all patients <14 years (n=559; 50.6% male), with newly diagnosed type 1 diabetes, in Lesser Poland between 1^st January 2006 and 31^st December 2017 (11 years).

RESULTS

The incidence ratio ranged significantly (p<0.001) from the lowest in 2006 (11.2/100,000/year) to the highest in 2012 (21.9/100,000/year). The mean age of diagnosis was 8.2±3.5 years. There was no trend in decreasing diagnosis age (p=0.43). The mean BMI-SDS was -0.4±1.2. Almost all children (91.6%) presented with BMI-SDS within the normal range at the time of diagnosis, with only 2.7% of cases being obese and 5.7% underweight at the moment of diagnosis. There was no clear trend at all in BMI-SDS over the study period.

CONCLUSION

These results do not corroborate an increase of type 1 incidence in paediatric population being associated with younger age of diagnosis and higher BMI-SDS. This implies that the accelerator hypothesis does not hold true in the study population.

Aetiology of type 1 diabetes: Physiological growth in children affects disease progression

The prevailing view is that type 1 diabetes (T1D) develops as a consequence of a severe decline in β-cell mass resulting from T-cell-mediated autoimmunity; however, progression from islet autoantibody seroconversion to overt diabetes and finally to total loss of C-peptide production occurs in most affected individuals only slowly over many years or even decades. This slow disease progression should be viewed in relation to the total β-cell mass of only 0.2 to 1.5 g in adults without diabetes. Focal lesions of acute pancreatitis with accumulation of leukocytes, often located around the ducts, are frequently observed in people with recent-onset T1D, and most patients display extensive periductal fibrosis, the end stage of inflammation. An injurious inflammatory adverse event, occurring within the periductal area, may have negative implications for islet neogenesis, dependent on stem cells residing within or adjacent to the ductal epithelium. This could in part prevent the 30-fold increase in β-cell mass that would normally occur during the first 20 years of life. This increase occurs in order to maintain glucose metabolism during the physiological increases in insulin production that are required to balance the 20-fold increase in body weight during childhood and increased insulin resistance during puberty. Failure to expand β-cell mass during childhood would lead to clinically overt T1D and could help to explain the apparently more aggressive form of T1D occurring in growing children when compared with that observed in affected adults.

The Role of Iron in Type 1 Diabetes Etiology: A Systematic Review of New Evidence on a Long-Standing Mystery

BACKGROUND

The incidence of type 1 diabetes (T1D) is rising, which might be due to the influence of environmental factors. Biological and epidemiological evidence has shown that excess iron is associated with beta-cell damage and impaired insulin secretion.

AIM

In this review, our aim was to assess the association between iron and the risk of T1D.

METHODS

A systematic literature search was performed in PubMed and EMBASE in July 2016. Studies investigating the effect of iron status/intake on the risk of developing T1D later were included, and study quality was evaluated. The results have been summarized in narrative form.

RESULTS

From a total of 931 studies screened, we included 4 observational studies evaluating iron intake from drinking water or food during early life and the risk of T1D. The quality of the studies was moderate to high assessed via the nine-star Newcastle Ottawa Scale. One out of the four studies included in this review found estimates of dietary iron intake to be associated with risk of T1D development, whereas three studies found no such relationship for estimates of iron in drinking water.

CONCLUSIONS

The limited number of studies included found dietary iron, but not iron in drinking water, to be associated with risk of T1D. Further studies are needed to clarify the association between iron and risk of T1D, especially studies including measurements of body iron status.

Stem cell therapy emerging as the key player in treating type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) is an autoimmune disease causing progressive destruction of pancreatic β cells, ultimately resulting in loss of insulin secretion producing hyperglycemia usually affecting children. Replacement of damaged β cells by cell therapy can treat it. Currently available strategies are insulin replacement and islet/pancreas transplantation. Unfortunately these offer rescue for variable duration due to development of autoantibodies. For pancreas/islet transplantation a deceased donor is required and various shortfalls of treatment include quantum, cumbersome technique, immune rejection and limited availability of donors. Stem cell therapy with assistance of cellular reprogramming and β-cell regeneration can open up new therapeutic modalities. The present review describes the history and current knowledge of T1DM, evolution of cell therapies and different cellular therapies to cure this condition.

The relationship between BMI and insulin resistance and progression from single to multiple autoantibody positivity and type 1 diabetes among TrialNet Pathway to Prevention participants

AIMS/HYPOTHESIS

The incidence of type 1 diabetes is increasing at a rate of 3-5% per year. Genetics cannot fully account for this trend, suggesting an influence of environmental factors. The accelerator hypothesis proposes an effect of metabolic factors on type 1 diabetes risk. To test this in the TrialNet Pathway to Prevention (PTP) cohort, we analysed the influence of BMI, weight status and insulin resistance on progression from single to multiple islet autoantibodies (Aab) and progression from normoglycaemia to diabetes.

METHODS

HOMA1-IR was used to estimate insulin resistance in Aab-positive PTP participants. Cox proportional hazards models were used to evaluate the effects of BMI, BMI percentile (BMI%), weight status and HOMA1-IR on the progression of autoimmunity or the development of diabetes.

RESULTS

Data from 1,310 single and 1,897 multiple Aab-positive PTP participants were included. We found no significant relationships between BMI, BMI%, weight status or HOMA1-IR and the progression from one to multiple Aabs. Similarly, among all Aab-positive participants, no significant relationships were found between BMI, weight status or HOMA1-IR and progression to diabetes. Diabetes risk was modestly increased with increasing BMI% among the entire cohort, in obese participants 13-20 years of age and with increasing HOMA1-IR in adult Aab-positive participants.

CONCLUSIONS/INTERPRETATION

Analysis of the accelerator hypothesis in the TrialNet PTP cohort does not suggest a broad influence of metabolic variables on diabetes risk. Efforts to identify other potentially modifiable environmental factors should continue.

Micro-RNA Binding Site Polymorphisms in the WFS1 Gene Are Risk Factors of Diabetes Mellitus

The absolute or relative lack of insulin is the key factor in the pathogenesis of diabetes mellitus. Although the connection between loss of function mutations of the WFS1 gene and DIDMOAD-syndrome including diabetes mellitus underpins the significance of wolframin in the pathogenesis, exact role of WFS1 polymorphic variants in the development of type 1 and type 2 diabetes has not been discovered yet. In this analysis, 787 patients with diabetes and 900 healthy people participated. Genotyping of the 7 WFS1 SNPs was carried out by TaqMan assays. Association study was performed by χ2-test in combination with correction for multiple testing. For functional analysis, the entire 3' UTR of the WFS1 gene was subcloned in a pMIR-Report plasmid and relative luciferase activities were determined. Linkage disequilibrium analysis showed a generally high LD within the investigated region, however the rs1046322 locus was not in LD with the other SNPs. The two miR-SNPs, rs1046322 and rs9457 showed significant association with T1DM and T2DM, respectively. Haplotype analysis also confirmed the association between the 3' UTR loci and both disease types. In vitro experiments showed that miR-185 reduces the amount of the resulting protein, and rs9457 miRSNP significantly influences the rate of reduction in a luciferase reporter assay. Genetic variants of the WFS1 gene might contribute to the genetic risk of T1DM and T2DM. Furthermore demonstrating the effect of rs9457 in binding of miR-185, we suggest that the optimal level of wolframin protein, potentially influenced by miR-regulation, is crucial in normal beta cell function.

Preserved C-peptide levels in overweight or obese compared with underweight children upon diagnosis of type 1 diabetes mellitus

PURPOSE

We hypothesized that overweight or obese children might develop type 1 diabetes mellitus (T1DM) early despite residual beta-cell function. Factors independently associated with preservation of C-peptide level were analyzed.

METHODS

We retrospectively reviewed the medical data of 135 children aged 2.1-16.5 years with autoimmune T1DM. Body mass index (BMI), pubertal stage, and glycosylated hemoglobin (HbA1c) and C-peptide levels were evaluated. Patients were assigned to underweight (22.2%), normal weight (63.7%), and overweight or obese (14.1%) groups according to their BMI.

RESULTS

Preservation of serum C-peptide levels (≥0.6 ng/mL) was found in 43.0% of subjects. With increasing BMI, the proportions of children with preserved C-peptide levels increased from 33.3% to 41.9% to 63.2%, with marginal significance (P=0.051). Interaction analysis indicated no effect of BMI score on age at onset associated with serum C-peptide levels. The lower the C-peptide level, the younger the age of onset (P<0.001), after adjustment for BMI z-score and HbA1c level. However, no significant relationship between BMI z-score or category and onset age was evident. Upon multivariate-adjusted modeling, the odds that the C-peptide level was preserved increased by 1.2 fold (P=0.001) per year of life, by 3.1 folds (P=0.015) in children presenting without (compared to with) ketoacidosis, and by 5.0 folds (P=0.042) in overweight or obese (compared to underweight) children.

CONCLUSION

Overweight or obese children had slightly more residual beta-cell function than did underweight children. However, we found no evidence that obesity temporally accelerates T1DM presentation.

Association between insulin resistance and risk of complications in children and adolescents with type 1 diabetes

BACKGROUND

It has been hypothesized that insulin resistance may be involved in the development of type 1 diabetes complications and early diagnosis would be important for their prevention. Our aim was to study insulin resistance in our population of children with type 1 diabetes and to identify associated early risk factors for micro- and macrovascular complications.

METHODS

A descriptive, cross-sectional study was conducted including 150 children with type 1 diabetes. Anthropometric, bioelectric impedance, carotid Doppler ultrasonography, electromyography, and conduction velocity studies were performed. Baseline plasma glucose, lipid profile, uric acid, plasma thyrotropin, glycosylated hemoglobin A1C, and microalbuminuria were assessed. More insulin-resistant patients were defined as those having an estimated glucose disposal rate (eGDR) value below the first quartile.

RESULTS

Clinically manifest microvascular complications were not found in any of the patients. More insulin-resistant patients had a greater sub scapular fold thickness, a higher incidence of obesity (12% vs. 1.7% p 0.007), higher fructosamine levels (496 vs. 403 p<0.00019, and a higher incidence of altered lipid metabolism (70% vs. 39% p 0.0007).

CONCLUSION

In the subgroup of patients with lower eGDR there were more children with lipid disorders, obesity, and worse diabetic control, which, if not corrected, may lead to development of micro- and macrovascular complications.

Prevalence of obesity was related to HLA-DQ in 2-4-year-old children at genetic risk for type 1 diabetes

OBJECTIVES

Body size is postulated to modulate type 1 diabetes as either a trigger of islet autoimmunity or an accelerator to clinical onset after seroconversion. As overweight and obesity continue to rise among children, the aim of this study was to determine whether human leukocyte antigen DQ (HLA-DQ) genotypes may be related to body size among children genetically at risk for type 1 diabetes.

METHODS

Repeated measures of weight and height were collected from 5969 children 2-4 years of age enrolled in The Environmental Determinants of Diabetes in the Young prospective study. Overweight and obesity was determined by the International Obesity Task Force cutoff values that correspond to body mass index (BMI) of 25 and 30 kg m(-)(2) at age 18.

RESULTS

The average BMI was comparable across specific HLA genotypes at every age point. The proportion of overweight was not different by HL A, but percent obesity varied by age with a decreasing trend among DQ2/8 carriers (P for trend=0.0315). A multivariable regression model suggested DQ2/2 was associated with higher obesity risk at age 4 (odds ratio, 2.41; 95% confidence interval, 1.21-4.80) after adjusting for the development of islet autoantibody and/or type 1 diabetes.

CONCLUSIONS

The HLA-DQ2/2 genotype may predispose to obesity among 2-4-year-old children with genetic risk for type 1 diabetes.

Environmental determinants of type 1 diabetes: a role for overweight and insulin resistance

Rates of type 1 diabetes are rising globally, with a decreasing proportion of high-risk genotypes and twin concordance rates below 50%. Therefore, environmental factors such as viruses, nutrition and overweight have been examined as putative aetiological agents. The accelerator hypothesis proposes that overweight and insulin resistance are central to both type 1 and type 2 diabetes and may explain, in part, the rise in type 1 diabetes incidence. The temporal rise in body mass index at type 1 diabetes onset and the observation that pre-diabetic children are heavier and more insulin resistant than their peers suggests convergence of type 1 and type 2 diabetes phenotypes. The influence of insulin resistance may begin in utero, although the aetiological role of birthweight in type 1 diabetes remains unclear. Further research to elucidate the role of these modifiable risk factors in today's obesogenic environment may provide future potential for diabetes prevention.

Is autoimmunity or insulin resistance the primary driver of type 1 diabetes?

Diabetes is usually classified as autoimmune or metabolic but, as difficulties have arisen with the taxonomy of diabetes, it may help to forego the conventional classification for a more inclusive model. Thus, all diabetes can be ascribed to beta cell insufficiency-hyperglycemia occurs only when the insulin supply fails to meet demand. Humans enter the world with a reserve of beta cells, which is eroded variably by apoptosis over the course of a lifetime. For most, the loss is slow and inconsequential but, for others fast enough to be critical within a lifetime. The challenge now is to define the factors that vary the tempo of beta cell loss, because tempo, not type, seems likely to determine whether diabetes occurs at all, in adulthood or in childhood. Insulin resistance is generally believed to underpin T2D, but has been a feature of insulin-dependent diabetes as well for nearly 80 years, though largely ignored until immunotherapy trials to test the autoimmunity hypothesis persistently failed to bring patient benefit. It seems possible that insulin resistance accelerates beta cell loss generally, its impact modulated by an immune response (autoimmunity) to the beta-cell stress whose intensity varies with immunogenotype. If so, the target for prevention of T1D might more logically lie with insulin sensitivity than with immunoregulation.

Cardiovascular disease in childhood: the role of obesity

In recent years, childhood obesity is becoming an epidemic health problem. It is now evident from many studies that childhood obesity is correlated with adult excess weight status and the development of risk factors for cardiovascular diseases in adulthood, including hypertension, type 2 diabetes mellitus, dyslipidemia, and metabolic syndrome. The exposure to obesity and to the above risk factors during childhood subsequently lead to atherosclerotic development, such as altered vascular structure and function, although the mechanisms are still unclear. Several non-invasive, and thus easy-to-obtain measures of arterial structure and function, have been shown to be clinically useful in providing information about vasculature early in the course of atherosclerosis, including measurement of endothelial function, carotid intima media thickness, and arterial stiffness. The early detection of cardiovascular abnormalities is essential because the control of the atherogenic process is more effective during its early stages. The present review focuses on the cardiovascular consequences of obesity, on the mechanisms and the methods of measurement of endothelial dysfunction in obese children and adolescents, and on the ways of intervention for the improvement of vascular health.

How do childhood diagnoses of type 1 diabetes cluster in time?

Background

Previous studies have indicated that type 1 diabetes may have an infectious origin. The presence of temporal clustering—an irregular temporal distribution of cases—would provide additional evidence that occurrence may be linked with an agent that displays epidemicity. We tested for the presence and form of temporal clustering using population-based data from northeast England.

Materials and Methods

The study analysed data on children aged 0–14 years diagnosed with type 1 diabetes during the period 1990–2007 and resident in a defined geographical region of northeast England (Northumberland, Newcastle upon Tyne, and North Tyneside). Tests for temporal clustering by time of diagnosis were applied using a modified version of the Potthoff-Whittinghill method.

Results

The study analysed 468 cases of children diagnosed with type 1 diabetes. There was highly statistically significant evidence of temporal clustering over periods of a few months and over longer time intervals (p<0.001). The clustering within years did not show a consistent seasonal pattern.

Conclusions

The study adds to the growing body of literature that supports the involvement of infectious agents in the aetiology of type 1 diabetes in children. Specifically it suggests that the precipitating agent or agents involved might be an infection that occurs in “mini-epidemics”.

Beta cell function and BMI in ethnically diverse children with newly diagnosed autoimmune type 1 diabetes

OBJECTIVE

To examine the relationship between BMI and beta-cell function at diagnosis of autoimmune type 1 diabetes (T1D) in a large group of ethnically diverse children.

METHODS

Cross-sectional analysis of 524 children (60.8% White, 19.5% Hispanic, 14.5% African-American, 5.2% other non-Hispanic; mean age = 9.8 yr [SD = 2.5]) with newly diagnosed autoimmune T1D.

RESULTS

As much as 22.2% of children were overweight or obese. Median random serum C-peptide was 0.40 ng/mL (25th-75th percentiles = 0.3-0.8), with median glycemia of 366 mg/dL (25th-75th percentiles = 271-505). Median C-peptide was 0.3, 0.5, 0.7, and 0.85 ng/mL, respectively, in underweight, normal weight, overweight, and obese children (p < 0.0001, Kruskal-Wallis). In the final model (p < 0.0001), the odds of having preserved C-peptide (≥0.6 ng/mL) were increased by 2.4-fold (95% CI = 1.2-4.9, p < 0.015) and 4.1-fold (1.9-8.5, p < 0.0001), respectively, in overweight and obese compared to lean children; 1.3-fold per each year of age; 2.5-fold in girls compared to boys; 4-fold in children who presented without, compared to with, diabetes ketoacidosis (DKA); and decreased by 21% for each point increase in HbA1c. Tanner stage, race/ethnicity, glycemia, and number of anti-islet antibodies expressed were not independently associated with preserved C-peptide. The association between BMI and C-peptide levels was significant in children with and without preserved C-peptide. Excluding patients who presented with DKA and/or using BMI obtained 5 wk after diagnosis did not alter the results.

CONCLUSION

Obese and overweight children compared to lean children have greater beta-cell function at the onset of autoimmune T1D. Prospective studies on the relationships among BMI, beta-cell function, and progression to clinical T1D are warranted.

Low risk HLA-DQ and increased body mass index in newly diagnosed type 1 diabetes children in the Better Diabetes Diagnosis study in Sweden

Objective

Type 1 diabetes and obesity has increased in childhood. We therefore tested the hypothesis that type 1 diabetes HLA-DQ risk genotypes may be associated with an increased body mass index (BMI).

Design

The type 1 diabetes high risk HLA-DQ A1*05:01-B1*02:01/A1*03:01-B1*03:02 genotype along with lower risk DQ genotypes were determined at the time of clinical onset by PCR and hybridization with allele-specific probes. Body mass index was determined after diabetes was stabilized.

Subjects

A total of 2403 incident type 1 diabetes children below 18 years of age were ascertained in the Swedish national Better Diabetes Diagnosis (BDD) studybetween May 2005 to September 2009. All children classified with type 1 diabetes including positivity for at least one islet autoantibody were investigated.

Results

Overall, type 1 diabetes HLA-DQ risk was negatively associated with BMI (p<0.0008). The proportion of the highest risk A1*05:01-B1*02:01/A1*03:01-B1*03:02 genotype decreased with increasing BMI (p<0.0004). However, lower risk type 1 diabetes DQ genotypes were associated with an increased proportion of patients who were overweight or obese (p<0.0001). Indeed, the proportion of patients with the low risk A1*05:01-B1*02:01/A1*05:01-B1*02:01 genotype increased with increasing body mass index (p<0.003). The magnitude of association on the multiplicative scale between the A1*05:01-B1*02:01/A1*05:01-B1*02:01 genotype and increased body mass index was significant (p<0.006). The odds ratio in patients with this genotype of being obese was 1.80 (95% CI 1.21–2.61; p<0.006). The increased proportion of overweight type 1 diabetes children with the A1*05:01-B1*02:01 haplotype was most pronounced in children diagnosed between 5 and 9 years of age.

Conclusions

Susceptibility for childhood type 1 diabetes was unexpectedly found to be associated with the A1*05:01-B1*02:01/A1*05:01-B1*02:01 genotype and an increased BMI. These results support the hypothesis that overweight may contribute to the risk of type 1 diabetes in children positive for HLA-DQ A1*05:01-B1*02:01.

AGE restriction in diabetes mellitus: a paradigm shift

Persistently elevated oxidative stress and inflammation precede or occur during the development of type 1 or type 2 diabetes mellitus and precipitate devastating complications. Given the rapidly increasing incidence of diabetes mellitus and obesity in the space of a few decades, new genetic mutations are unlikely to be the cause, instead pointing to environmental initiators. A hallmark of contemporary culture is a preference for thermally processed foods, replete with pro-oxidant advanced glycation endproducts (AGEs). These molecules are appetite-increasing and, thus, efficient enhancers of overnutrition (which promotes obesity) and oxidant overload (which promotes inflammation). Studies of genetic and nongenetic animal models of diabetes mellitus suggest that suppression of host defenses, under sustained pressure from food-derived AGEs, may potentially shift homeostasis towards a higher basal level of oxidative stress, inflammation and injury of both insulin-producing and insulin-responsive cells. This sequence promotes both types of diabetes mellitus. Reducing basal oxidative stress by AGE restriction in mice, without energy or nutrient change, reinstates host defenses, alleviates inflammation, prevents diabetes mellitus, vascular and renal complications and extends normal lifespan. Studies in healthy humans and in those with diabetes mellitus show that consumption of high amounts of food-related AGEs is a determinant of insulin resistance and inflammation and that AGE restriction improves both. This Review focuses on AGEs as novel initiators of oxidative stress that precedes, rather than results from, diabetes mellitus. Therapeutic gains from AGE restriction constitute a paradigm shift.

Increased maternal Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) associated with older age at diagnosis of Type 1 diabetes in offspring

AIMS

Obesity and insulin resistance have been linked to rising incidence and earlier onset of Type 1 diabetes. Inherited differences in insulin action might also influence the evolution of Type 1 diabetes.Our aim was to determine whether parental BMI and insulin resistance influences age of onset of Type 1 diabetes in their offspring.

METHODS

BMI standard deviation score and age at diagnosis of Type 1 diabetes was examined in 227 children, and in 206 of these was compared with local matched control subjects. Non-diabetic parents of a subgroup of 80 children with Type 1 diabetes were recruited. Parental BMI was compared with local adult control subjects. The relationship between parental BMI, waist-hip ratio, homeostasis model assessment of insulin resistance (HOMA-IR), leptin and adiponectin levels and age at diagnosis of Type 1 diabetes in offspring was examined.

RESULTS

We found no relationship between age at diagnosis of Type 1 diabetes in children and BMI standard deviation score (P = 0.5). Children with Type 1 diabetes and their parents were heavier than matched control subjects (mean BMI standard deviation score sd in children = 0.66 1.06 vs. 0.32 1.16 in control subjects, P = 0.002; mean parental BMI sd 27.7 0.4 vs. 25.5 0.4 kg ⁄m2 in control subjects; P < 0.0001). Maternal HOMA-IR accounted for 20% of variation in age at diagnosis (P < 0.001) with increasing maternal insulin resistance associated with later age at diagnosis of Type 1 diabetes.

CONCLUSIONS

Childrenwith Type 1 diabetes and their parents have an increased BMI at diagnosis.Maternal insulin resistance is associated with later onset of Type 1 diabetes in children.

Circadian blood pressure variability in type 1 diabetes subjects and their nondiabetic siblings - influence of erythrocyte electron transfer

BACKGROUND

Normotensive non-diabetic relatives of type 1 diabetes (T1D) patients have an abnormal blood pressure response to exercise testing that is associated with indices of metabolic syndrome and increased oxidative stress. The primary aim of this study was to investigate the circadian variability of blood pressure and the ambulatory arterial stiffness index (AASI) in healthy siblings of T1D patients vs healthy control subjects who had no first-degree relative with T1D. Secondary aims of the study were to explore the influence of both cardiovascular autonomic function and erythrocyte electron transfer activity as oxidative marker on the ambulatory blood pressure profile.

METHODS

Twenty-four hour ambulatory blood pressure monitoring (ABPM) was undertaken in 25 controls, 20 T1D patients and 20 siblings. In addition to laboratory examination (including homeostasis model assessment of insulin sensitivity) and clinical testing of autonomic function, we measured the rate of oxidant-induced erythrocyte electron transfer to extracellular ferricyanide (RBC vfcy).

RESULTS

Systolic blood pressure (SBP) midline-estimating statistic of rhythm and pulse pressure were higher in T1D patients and correlated positively with diabetes duration and RBC vfcy; autonomic dysfunction was associated with diastolic BP ecphasia and increased AASI. Siblings had higher BMI, lower insulin sensitivity, larger SBP amplitude, and higher AASI than controls. Daytime SBP was positively, independently associated with BMI and RBC vfcy. Among non-diabetic people, there was a significant correlation between AASI and fasting plasma glucose.

CONCLUSIONS

Siblings of T1D patients exhibited a cluster of sub-clinical metabolic abnormalities associated with consensual perturbations in BP variability. Moreover, our findings support, in a clinical setting, the proposed role of transplasma membrane electron transport systems in vascular pathobiology.

Evaluating geographic variation in type 1 and type 2 diabetes mellitus incidence in youth in four US regions

We evaluated geographic variation in type 1 and type 2 diabetes mellitus (T1DM, T2DM) in four regions of the United States. Data on 807 incident T1DM cases diabetes and 313 T2DM cases occurring in 2002-03 in South Carolina (SC) and Colorado (CO), 5 counties in Washington (WA), and an 8 county region around Cincinnati, Ohio (OH) among youth aged 10-19 years were obtained from the SEARCH for Diabetes in Youth Study. Geographic patterns were evaluated in a Bayesian framework. Incidence rates differed between the study regions, even within race/ethnic groups. Significant small-area variation within study region was observed for T1DM and T2DM. Evidence for joint spatial correlation between T1DM and T2DM was present at the county level for SC (r(SC)=0.31) and CO non-Hispanic Whites (r(CO)=0.40) and CO Hispanics (r(CO)=0.72). At the tract level, no evidence for meaningful joint spatial correlation was observed (r(SC)=-0.02; r(CO)=-0.02; r(OH)=0.03; and r(WA=)0.09). Our study provides evidence for the presence of both regional and small area, localized variation in type 1 and type 2 incidence among youth aged 10-19 years in the United States.

Differential effects of leptin receptor mutation on male and female BBDR Gimap5-/Gimap5- spontaneously diabetic rats

Rodents homozygous for autosomal leptin receptor gene mutations not only become obese, insulin resistant, and hyperleptinemic but also develop a dysregulated immune system. Using marker-assisted breeding to introgress the Koletsky rat leptin receptor mutant (lepr-/lepr-), we developed a novel congenic BBDR.(lepr-/lepr-) rat line to study the development of obesity and type 2 diabetes (T2D) in the BioBreeding (BB) diabetes-resistant (DR) rat. While heterozygous lepr (-/+) or homozygous (+/+) BBDR rats remained lean and metabolically normal, at 3 wk of age all BBDR.(lepr-/lepr-) rats were obese without hyperglycemia. Between 45 and 70 days of age, male but not female obese rats developed T2D. We had previously developed congenic BBDR.(Gimap5-/Gimap5-) rats, which carry an autosomal frameshift mutation in the Gimap5 gene linked to lymphopenia and spontaneous development of type 1 diabetes (T1D) without sex differences. Because the autoimmune-mediated destruction of pancreatic islet beta-cells may be affected not only by obesity but also by the absence of leptin receptor signaling, we next generated BBDR.(lepr-/lepr-,Gimap5-/Gimap5-) double congenic rats carrying the mutation for Gimap5 and T1D as well as the Lepr mutation for obesity and T2D. The hyperleptinemia rescued end-stage islets in BBDR.(lepr-/lepr-,Gimap5-/Gimap5-) congenic rats and induced an increase in islet size in both sexes, while T1D development was delayed and reduced only in females. These results demonstrate that obesity and T2D induced by introgression of the Koletsky leptin receptor mutation in the BBDR rat result in islet expansion associated with protection from T1D in female but not male BBDR.(lepr-/lepr-,Gimap5-/Gimap5-) congenic rats. BBDR.(lepr-/lepr-,Gimap5-/Gimap5-) congenic rats should prove valuable to study interactions between lack of leptin receptor signaling, obesity, and sex-specific T2D and T1D.

Reappraising the stereotypes of diabetes in the modern diabetogenic environment

The prevailing concentration of blood glucose is a result of the integrated regulation of insulin secretion and insulin action. Nevertheless, the classic stereotypes of diabetes are dichotomous: type 1 diabetes mellitus (T1DM) is attributed to impaired insulin secretion, and type 2 diabetes mellitus (T2DM) is primarily attributed to impaired insulin action (insulin resistance). The available evidence indicates that this view is overly simplistic. Impaired insulin secretion (beta-cell dysfunction) is also a feature of T2DM, and insulin resistance is also a risk factor for the development of T1DM. Moreover, with the increasing incidence of T2DM and T1DM in both developed and developing countries, attributed to environmental factors, the existence of 'hybrid' diabetes types that have clinical and pathogenetic features of both conditions is becoming clearly evident. A common thread across the spectrum of diabetes might be the activation of innate immunological and inflammatory pathways by a proinflammatory environment, which leads to beta-cell dysfunction in T2DM, insulin resistance in both T2DM and T1DM, and enhanced adaptive immunity that kills beta cells in T1DM. Embracing a holistic view of the diabetes syndrome will help us to understand the environmental basis for the epidemic of diabetes and improve preventative strategies.

Weight gain in children and adolescents during 45 weeks treatment with clozapine, olanzapine and risperidone

The aim of this study was to evaluate long-term weight gain associated with clozapine, olanzapine, and risperidone treatment and its clinical risk factors in children and adolescents. At four child and adolescent psychiatric departments, the weight and body mass index of initially hospitalized patients (aged 9.0-21.3 years) treated with clozapine (n = 15), olanzapine (n = 8), and risperidone (n = 10) were prospectively monitored for 45 weeks. Clinical risk factors (age, gender, baseline weight, dosage, drug-naivety) were tested for their association with weight gain in the three groups. All three groups experienced significant weight gain between baseline and endpoint. The absolute and percentage average weight gains were significantly higher for the olanzapine group (16.2 +/- 8.8 kg; 30.1 +/- 18.9%) than for the clozapine (9.5 +/- 10.4 kg; 14.8 +/- 15.8%) and the risperidone (7.2 +/- 5.3 kg; 11.5 +/- 6.0%) groups. Olanzapine is associated with extreme long-term weight gain in children and adolescents that, in addition, is much higher than that expected in adults. Clozapine and risperidone are associated with a less marked weight gain in children and adolescents but also much higher than that expected in adults. These differences may affect compliance with medication and health risk.