Introducing the Endotype Concept to Address the Challenge of Disease Heterogeneity in Type 1 Diabetes

The clinical diagnosis of new-onset type 1 diabetes has, for many years, been considered relatively straightforward. Recently, however, there is increasing awareness that within this single clinical phenotype exists considerable heterogeneity: disease onset spans the complete age range; genetic susceptibility is complex; rates of progression differ markedly, as does insulin secretory capacity; and complication rates, glycemic control, and therapeutic intervention efficacy vary widely. Mechanistic and immunopathological studies typically show considerable patchiness across subjects, undermining conclusions regarding disease pathways. Without better understanding, type 1 diabetes heterogeneity represents a major barrier both to deciphering pathogenesis and to the translational effort of designing, conducting, and interpreting clinical trials of disease-modifying agents. This realization comes during a period of unprecedented change in clinical medicine, with increasing emphasis on greater individualization and precision. For complex disorders such as type 1 diabetes, the option of maintaining the "single disease" approach appears untenable, as does the notion of individualizing each single patient's care, obliging us to conceptualize type 1 diabetes less in terms of phenotypes (observable characteristics) and more in terms of disease endotypes (underlying biological mechanisms). Here, we provide our view on an approach to dissect heterogeneity in type 1 diabetes. Using lessons from other diseases and the data gathered to date, we aim to delineate a roadmap through which the field can incorporate the endotype concept into laboratory and clinical practice. We predict that such an effort will accelerate the implementation of precision medicine and has the potential for impact on our approach to translational research, trial design, and clinical management.

Heterogeneity of type I diabetes: analysis of monozygotic twins in Great Britain and the United States

AIMS

To determine the risk, hazard rate and factors affecting progression to diabetes in monozygotic twins of patients with Type I (insulin-dependent) diabetes mellitus.

METHODS

Prospective analysis was done of two cohorts of non-diabetic monozygotic twins of patients with Type I diabetes from Great Britain (n = 134) and the United States (n = 53).

RESULTS

The diabetes-free survival analysis was similar between both cohorts (p = 0.6). The combined survival analysis (n = 187, median follow-up = 17.7 years, range = 0.01-57) at 40 years of discordance estimated a 39% probability of diabetes for the initially discordant twin. Survival analysis with left truncation of data estimated that probability to be 50%. For twins who became concordant (n = 47), the median discordance time was 4.2 years (range 0.4 to 39), exceeding 15 years in 23.4%. Twins of probands diagnosed at 24 years of age or younger had a 38% probability of diabetes by 30 years of discordance, compared with 6% for twins of probands diagnosed after 24 years of age (p = 0.004). The twins of probands diagnosed before 15 years of age had the highest diabetes hazard rate in the first discordance year, decreasing thereafter. By survival analysis, diabetes risk was higher in twins who were heterozygous for DR3-DQ2 and DR4-DQ8 than in twins with neither DR3-DQ2 nor DR4-DQ8 (p < 0.05).

CONCLUSION/INTERPRETATION

Monozygotic twins of patients with Type I diabetes from two different countries had similar rates of progression to diabetes. Whereas most twins did not develop diabetes, 25% of the twins who progressed did so after more than 14 years of discordance. An age-related heterogeneity was observed, with higher progression to diabetes for twins of patients diagnosed at a younger age.

Racial-Ethnic Inequity in Young Adults With Type 1 Diabetes

CONTEXT

Minority young adults (YA) currently represent the largest growing population with type 1 diabetes (T1D) and experience very poor outcomes. Modifiable drivers of disparities need to be identified, but are not well-studied.

OBJECTIVE

To describe racial-ethnic disparities among YA with T1D and identify drivers of glycemic disparity other than socioeconomic status (SES).

DESIGN

Cross-sectional multicenter collection of patient and chart-reported variables, including SES, social determinants of health, and diabetes-specific factors, with comparison between non-Hispanic White, non-Hispanic Black, and Hispanic YA and multilevel modeling to identify variables that account for glycemic disparity apart from SES.

SETTING

Six diabetes centers across the United States.

PARTICIPANTS

A total of 300 YA with T1D (18-28 years: 33% non-Hispanic White, 32% non-Hispanic Black, and 34% Hispanic).

MAIN OUTCOME

Racial-ethnic disparity in HbA1c levels.

RESULTS

Non-Hispanic Black and Hispanic YA had lower SES, higher HbA1c levels, and much lower diabetes technology use than non-Hispanic White YA (P < 0.001). Non-Hispanic Black YA differed from Hispanic, reporting higher diabetes distress and lower self-management (P < 0.001). After accounting for SES, differences in HbA1c levels disappeared between non-Hispanic White and Hispanic YA, whereas they remained for non-Hispanic Black YA (+ 2.26% [24 mmol/mol], P < 0.001). Diabetes technology use, diabetes distress, and disease self-management accounted for a significant portion of the remaining non-Hispanic Black-White glycemic disparity.

CONCLUSION

This study demonstrated large racial-ethnic inequity in YA with T1D, especially among non-Hispanic Black participants. Our findings reveal key opportunities for clinicians to potentially mitigate glycemic disparity in minority YA by promoting diabetes technology use, connecting with social programs, and tailoring support for disease self-management and diabetes distress to account for social contextual factors.

Genetics of type 1 diabetes

Type 1 diabetes (T1D) results from immune-mediated loss of pancreatic beta cells leading to insulin deficiency. It is the most common form of diabetes in children, and its incidence is on the rise. This article reviews the current knowledge on the genetics of T1D. In particular, we discuss the influence of HLA and non-HLA genes on T1D risk and disease progression through the preclinical stages of the disease, and the development of genetic scores that can be applied to disease prediction. Racial/ethnic differences, challenges and future directions in the genetics of T1D are also discussed.

Self-antigen-presenting cells expressing diabetes-associated autoantigens exist in both thymus and peripheral lymphoid organs

Recent reports indicate that genes with tissue-restricted expression, including those encoding the type 1 diabetes autoantigens insulin, glutamic acid decarboxylase (GAD), and the tyrosine-phosphatase-like protein IA-2 (or ICA512), are transcribed in the thymus. The reported modulation of diabetes susceptibility by genetically determined differences in thymic insulin levels and studies in transgenic mice provide correlative and functional evidence that thymic expression of peripheral proteins is crucial for immunological self-tolerance. However, there are no specific data about the existence, tissue distribution, phenotype, and function of those cells that express insulin and other self-antigens in the human thymus. We find that the human thymus harbors specialized cells synthesizing (pro)insulin, GAD, and IA-2, mainly localized in the medulla, and we demonstrate such cells also in peripheral lymphoid organs (spleen and lymph nodes). Phenotypic analysis qualifies these cells as antigen-presenting cells (APCs), including both dendritic cells and macrophages. These cells often appear surrounded by apoptotic lymphocytes, both in thymus and spleen, and may therefore be involved in the deletion of autoreactive lymphocytes. Our findings demonstrate the existence of, and define the tissue distribution and phenotype of, a novel subset of APCs expressing self-antigens in human lymphoid organs that appear to be involved in the regulation of self-tolerance throughout life.

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H, Suomalainen H, Colman P, Healy F, Mesfin S, Redl L, Wentworth J, Willis J, Farley M, Harrison L, Perry C, Williams F, Mayo A, Paxton J, Thompson V, Volin L, Fenton C, Carr L, Lemon E, Swank M, Luidens M, Salgam M, Sharma V, Schade D, King C, Carano R, Heiden J, Means N, Holman L, Thomas I, Madrigal D, Muth T, Martin C, Plunkett C, Ramm C, Auchus R, Lane W, Avots E, Buford M, Hale C, Hoyle J, Lane B, Muir A, Shuler S, Raviele N, Ivie E, Jenkins M, Lindsley K, Hansen I, Fadoju D, Felner E, Bode B, Hosey R, Sax J, Jefferies C, Mannering S, Prentis R, She J, Stachura M, Hopkins D, Williams J, Steed L, Asatapova E, Nunez S, Knight S, Dixon P, Ching J, Donner T, Longnecker S, Abel K, Arcara K, Blackman S, Clark L, Cooke D, Plotnick L, Levin P, Bromberger L, Klein K, Sadurska K, Allen C, Michaud D, Snodgrass H, Burghen G, Chatha S, Clark C, Silverberg J, Wittmer C, Gardner J, LeBoeuf C, Bell P, McGlore O, Tennet H, Alba N, Carroll M, Baert L, Beaton H, Cordell E, Haynes A, Reed C, Lichter 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Manley L, Nemery R, Charlton W, Smith P, Kerr L, Steindel-Kopp B, Alamaguer M, Tabisola-Nuesca E, Pendersen A, Larson N, Cooper-Olviver H, Chan D, Fitz-Patrick D, Carreira T, Park Y, Ruhaak R, Liljenquist D. A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Genetic control of autoimmunity in Type I diabetes and associated disorders

Type I (insulin-dependent) diabetes mellitus is a heterogeneous disease with major subdivisions termed Type 1A (immune-mediated) and Type 1B. Immune-mediated diabetes is also heterogeneous with "monogenic", oligogenic, and polygenic forms present in humans and in animal models. Single-gene mutations of two transcription factors have been recently identified in rare syndromes of autoimmunity with type 1A diabetes: autoimmune polyendocrine syndrome type 1 (APS-1) and X-linked polyendocrinopathy, immune dysfunction and diarrhoea (XPID). For more common forms of diabetes, susceptibility loci within the major histocompatibility complex and at the insulin locus have been identified. Both DQ(*) and DR* alleles provide susceptibility and certain alleles dominant protection. In the Diabetes Autoimmunity Study of the Young approximately 50 % of the siblings studied with the highest-risk HLA genotype develop anti-islet autoantibodies by age 3. Insulin could be a crucial autoantigen related to genetic susceptibility. The crystal structure of the high-risk allele, HLA-DQ8, complexed with an insulin peptide has just been reported. Insulin production by macrophage-dendritic cells within the thymus and lymphoid organs could underlie insulin gene polymorphisms influencing the risk of diabetes. Genome-wide scans for linkage in animal models and in humans have not conclusively identified other susceptibility genes though many loci have been implicated. We favour the hypothesis that HLA is a major determinant of susceptibility in animal models and in most families, and that the search for diabetogenes should concentrate on unique families to decrease heterogeneity and favour the eventual discovery of genes influencing risk.

Genetics of type 1A diabetes

Type 1A diabetes is an autoimmune disease with genetic and environmental factors contributing to its etiology. Twin studies, family studies, and animal models have helped to elucidate the genetics of autoimmune diabetes. Most of the genetic susceptibility is accounted for by human leukocyte antigen (HLA) alleles. The most-common susceptibility haplotypes are DQA1*0301-DQB1*0302 and DQA1*0501-DQB1*0201. Less-common haplotypes such as DQA1*0401-DQB1*0402 and DQA1*0101-DQB1*0501 are associated with high risk for diabetes; however, large study populations are needed to analyze their effect. The DQA1*0102-DQB1*0602 haplotype is associated with diabetes resistance. DR molecules, such as DRB1*1401, confer protection from diabetes. Monozygotic twins of patients with type 1A diabetes have a diabetes risk higher than that for HLA-identical ordinary siblings, suggesting that non-HLA genes contribute to diabetes risk. Polymorphisms in the regulatory region of the insulin gene (designated IDDM2), polymorphisms in cytotoxic T lymphocyte antigen-4 (CTLA-4) gene (IDDM12), and other genes are likely to contribute to diabetes risk and susceptibility in some individuals. In selected families, major diabetogenes (e.g., IDDM17, autoimmune regulator gene (AIRE)) are likely to be of importance. Other factors--either noninherited genes (i.e., somatic mutations and T-cell receptor or immunoglobulin rearrangements) or environment--may have a role in progression to diabetes. This is suggested by the finding that the risk for monozygotic twins of patients with type 1A diabetes is not 100 percent. Studying the genetics of type 1A diabetes will allow us to better define this disease, to improve our ability to identify individuals at risk, and to predict the risk of associated disorders.

The clinical consequences of heterogeneity within and between different diabetes types

Advances in molecular methods and the ability to share large population-based datasets are uncovering heterogeneity within diabetes types, and some commonalities between types. Within type 1 diabetes, endotypes have been discovered based on demographic (e.g. age at diagnosis, race/ethnicity), genetic, immunological, histopathological, metabolic and/or clinical course characteristics, with implications for disease prediction, prevention, diagnosis and treatment. In type 2 diabetes, the relative contributions of insulin resistance and beta cell dysfunction are heterogeneous and relate to demographics, genetics and clinical characteristics, with substantial interaction from environmental exposures. Investigators have proposed approaches that vary from simple to complex in combining these data to identify type 2 diabetes clusters relevant to prognosis and treatment. Advances in pharmacogenetics and pharmacodynamics are also improving treatment. Monogenic diabetes is a prime example of how understanding heterogeneity within diabetes types can lead to precision medicine, since phenotype and treatment are affected by which gene is mutated. Heterogeneity also blurs the classic distinctions between diabetes types, and has led to the definition of additional categories, such as latent autoimmune diabetes in adults, type 1.5 diabetes and ketosis-prone diabetes. Furthermore, monogenic diabetes shares many features with type 1 and type 2 diabetes, which make diagnosis difficult. These challenges to the current classification framework in adult and paediatric diabetes require new approaches. The 'palette model' and the 'threshold hypothesis' can be combined to help explain the heterogeneity within and between diabetes types. Leveraging such approaches for therapeutic benefit will be an important next step for precision medicine in diabetes. Graphical abstract.

Second international consensus report on gaps and opportunities for the clinical translation of precision diabetes medicine

Precision medicine is part of the logical evolution of contemporary evidence-based medicine that seeks to reduce errors and optimize outcomes when making medical decisions and health recommendations. Diabetes affects hundreds of millions of people worldwide, many of whom will develop life-threatening complications and die prematurely. Precision medicine can potentially address this enormous problem by accounting for heterogeneity in the etiology, clinical presentation and pathogenesis of common forms of diabetes and risks of complications. This second international consensus report on precision diabetes medicine summarizes the findings from a systematic evidence review across the key pillars of precision medicine (prevention, diagnosis, treatment, prognosis) in four recognized forms of diabetes (monogenic, gestational, type 1, type 2). These reviews address key questions about the translation of precision medicine research into practice. Although not complete, owing to the vast literature on this topic, they revealed opportunities for the immediate or near-term clinical implementation of precision diabetes medicine; furthermore, we expose important gaps in knowledge, focusing on the need to obtain new clinically relevant evidence. Gaps include the need for common standards for clinical readiness, including consideration of cost-effectiveness, health equity, predictive accuracy, liability and accessibility. Key milestones are outlined for the broad clinical implementation of precision diabetes medicine.

Genetic determination of islet cell autoimmunity in monozygotic twin, dizygotic twin, and non-twin siblings of patients with type 1 diabetes: prospective twin study

OBJECTIVE

To test the hypothesis that non-diabetic dizygotic and monozygotic twin siblings of patients with type 1 diabetes have a similar high prevalence of islet cell autoantibodies, thus suggesting that islet cell autoimmunity is mainly environmentally determined.

DESIGN

Prospective twin study.

SETTING

Two specialist centres for diabetes in the United States.

PARTICIPANTS

Non-diabetic monozygotic twin (n=53), dizygotic twin (n=30), and non-twin (n=149) siblings of patients with type 1 diabetes; 101 controls.

MAIN OUTCOME MEASURES

Analysis of progression to diabetes and expression of anti-islet autoantibodies.

RESULTS

Monozygotic twin siblings had a higher risk of progression to diabetes (12/53) than dizygotic twin siblings (0/30; P<0.005). At the last follow up 22 (41.5%) monozygotic twin siblings expressed autoantibodies compared with 6 (20%) dizygotic twin siblings (P<0.05), 16 (10.7%) non-twin siblings (P<0.0001), and 6 (5.9%) controls (P<0.0001). Monozygotic twin siblings expressed multiple (>/=2) antibodies more often than dizygotic twin siblings (10/38 v 1/23; P<0.05). By life table analysis the probability of developing positive autoantibodies was higher among the monozygotic twin siblings bearing the diabetes associated HLA DQ8/DQ2 genotype than in those without this genotype (64.2% (95% confidence interval 32.5% to 96%) v 23.5% (7% to 40%) at 10 years of discordance; P<0.05).

CONCLUSION

Monozygotic and dizygotic twins differ in progression to diabetes and expression of islet cell autoantibodies. Dizygotic twin siblings are similar to non-twin siblings. These two observations suggest that genetic factors play an important part in determination of islet cell autoimmunity, thus rejecting the hypothesis. In addition, there is a high penetrance of islet cell autoimmunity in DQ8/DQ2 monozygotic twin siblings.

Matrix solid-phase dispersion microextraction and determination by high-performance liquid chromatography with UV detection of pesticide residues in citrus fruit

A multiresidue method based on matrix solid-phase dispersion (MSPD) microextraction was studied to determine the carbamate, benfuracarb, and urea insecticides, diflubenzuron, flufenoxuron hexaflumuron and hexythiazox, used in control of citrus pests. Optimisation of different parameters, such as the type of solid support for matrix dispersion, elution solvents and the clean-up step were carried out. The method used 0.5 g of orange sample, C8 bonded silica as MSPD sorbent and dichloromethane as eluting solvent. Recoveries, at spiked concentrations below the maximum residue levels established by Spanish Government, were between 74 and 84% with relative standard deviations ranging from 2 to 4%. The limits of quantification were from 0.15 to 0.25 microgram/g using high-performance liquid chromatography with UV detection at 200 nm. The method may be useful as a screening protocol for the determination of these newly developed pesticides in citrus samples.

Excess BMI in Childhood: A Modifiable Risk Factor for Type 1 Diabetes Development?

OBJECTIVE

We aimed to determine the effect of elevated BMI over time on the progression to type 1 diabetes in youth.

RESEARCH DESIGN AND METHODS

We studied 1,117 children in the TrialNet Pathway to Prevention cohort (autoantibody-positive relatives of patients with type 1 diabetes). Longitudinally accumulated BMI above the 85th age- and sex-adjusted percentile generated a cumulative excess BMI (ceBMI) index. Recursive partitioning and multivariate analyses yielded sex- and age-specific ceBMI thresholds for greatest type 1 diabetes risk.

RESULTS

Higher ceBMI conferred significantly greater risk of progressing to type 1 diabetes. The increased diabetes risk occurred at lower ceBMI values in children <12 years of age compared with older subjects and in females versus males.

CONCLUSIONS

Elevated BMI is associated with increased risk of diabetes progression in pediatric autoantibody-positive relatives, but the effect varies by sex and age.

Race, socioeconomic status, and treatment center are associated with insulin pump therapy in youth in the first year following diagnosis of type 1 diabetes

BACKGROUND

Increasing numbers of children and adolescents with type 1 diabetes (T1D) have been placed on insulin pump therapy. Nevertheless, data are limited regarding patterns of pump use during the first year of treatment and the clinical and socioeconomic factors associated with early use of pump therapy. Therefore, we sought to determine factors associated with pump therapy within the first year of diagnosis in youth enrolled in the Pediatric Diabetes Consortium (PDC) T1D New-Onset (NeOn) Study.

SUBJECTS AND METHODS

The NeOn Study includes youth <19 years old at T1D diagnosis who have been followed from the time of diagnosis at seven U.S. pediatric diabetes centers. Cox regression was used to determine factors associated with transition from injection to pump therapy during the first year of T1D in 1,012 participants.

RESULTS

Twenty-seven percent (n=254) of participants began pump therapy within the first year of diagnosis, ranging from 18% to 59% among the seven centers. After adjusting for center effect, factors associated with pump use in multivariate analysis included private health insurance (37% vs. 7%; P<0.001), having annual household income over $100,000 (50% vs. 15%; P<0.001), and non-Hispanic white race (36% vs. 11%; P<0.001). The hemoglobin A1c level did not appear to influence the decision to initiate pump use.

CONCLUSIONS

Participants of non-Hispanic white race and higher socioeconomic status were more likely to be placed on pumps during the first year. Further investigations are needed to gain a better understanding of barriers to use of pumps in youth with T1D, especially in disadvantaged and minority families.

Depressive Symptoms in Youth With Type 1 or Type 2 Diabetes: Results of the Pediatric Diabetes Consortium Screening Assessment of Depression in Diabetes Study

OBJECTIVE

To evaluate the frequency of depressive symptoms and the diagnosis and management of depression in youth with type 1 diabetes (T1D) and type 2 diabetes (T2D) enrolled in the Pediatric Diabetes Consortium T1D and T2D registries.

RESEARCH DESIGN AND METHODS

The Children's Depression Inventory (CDI) 2 Self-Report (Short) version was completed by 261 T1D and 339 T2D youth aged 10-17 years.

RESULTS

Symptoms of depression were identified in 13% of T1D and 22% of T2D (P = 0.007) participants; of these, only 4% of T1D and 9% of T2D youth were treated by a therapist within the prior 12 months. Depressive symptoms were associated with lower family income (P = 0.006) and obesity (P = 0.002) in T1D but not T2D youth.

CONCLUSIONS

Depressive symptoms are more frequent than diagnosed depression in youth with T1D or T2D. These results underscore the need for regular depression screening and appropriate referral for youth with diabetes.

Description of Enteromyxum scophthalmi gen. nov., sp. nov. (Myxozoa), an intestinal parasite of turbot (Scophthalmus maximus L.) using morphological and ribosomal RNA sequence data

A new Myxozoa species causing enteritis and death in cultured turbot, Scophthalmus maximus, is described at light and electron microscope levels. In addition, small subunit ribosomal RNA gene sequences (SSU rDNA) from the new species and from similar myxozoans were obtained and used for phylogenetic inference, as complementary criteria to resolve its taxonomic classification. The new parasite is closely related to Myxidium leei, another enteric histozoic species from marine fish. However, the ascription of M. leei to the genus Myxidium was based on weak morphological evidence and is not supported by our rDNA data analysis. A close relationship with Zschokkella, the other morphologically related myxozoan genus is also not supported. The combined morphological and molecular study results in the establishment of the new genus Enteromyxum to accommodate the new species E. scophthalmi, and the former M. leei, which is transferred to the new genus as Enteromyxum leei (Diamant, Lom & Dyková 1994) n. comb. This genus of marine, histozoic and enteric myxozoans includes significant parasite species for marine finfish culture.

Cryptosporidium scophthalmi n. sp. (Apicomplexa: Cryptosporidiidae) from cultured turbot Scophthalmus maximus. Light and electron microscope description and histopathological study

Cryptosporidium scophthalmi n. sp. is described from the turbot Scophthalmus maximus L., sampled from different farms on the coast of NW Spain. The parasite was found mainly in the intestinal epithelium and very seldom in the stomach. Oocysts were almost spherical, with 4 naked sporozoites and a residuum, and measured 3.7-5.03 x 3.03-4.69 microm (mean 4.44 x 3.91) (shape index 1.05-1.34, mean 1.14). Sporulation was endogenous, as fully sporulated oocysts were found within the intestinal epithelium, lumen and faeces. Merogonial and gamogonial stages were in the typical extracytoplasmic position, whereas sporogonial stages were deep within the epithelium. Oocysts and other stages of C. scophthalmi comply with most of the diagnostic features of the genus Cryptosporidium, but differ from all hitherto described species. Ultrastructural features, including the characteristic feeding organelle, were mainly comparable with those of other Cryptosporidium species. Mitochondria were frequently observed in sporozoites. Infection prevalence was very variable, and juvenile fish were most frequently and intensively parasitised. External clinical signs were not detected, although some fish showed intestinal distension at necropsy. The marked histopathological damage occurring in severe infection includes distension of epithelial cells by large vacuoles, containing clusters of oocysts, and can lead to sloughing of epithelial cell remnants and oocysts or even detachment of intestinal mucosa. An inflammatory reaction involving leucocyte infiltration was sometimes observed.

Prevalence of cardiovascular risk factors in youth with type 1 diabetes and elevated body mass index

AIM

The prevalence of cardiovascular risk factors in children with type 1 diabetes and elevated BMI in the USA is poorly defined. We aimed to test the hypothesis that children with type 1 diabetes who are overweight or obese have increased frequencies of hypertension, dyslipidemia, and micro-/macroalbuminuria compared to their healthy weight peers.

METHODS

We studied 11,348 children 2 to <18 years of age enrolled in T1D Exchange between September 2010 and August 2012 with type 1 diabetes for ≥1 year and BMI ≥ 5th age-/sex-adjusted percentile (mean age 12 years, 49 % female, 78 % non-Hispanic White). Overweight and obesity were defined based on Centers for Disease Control and Prevention criteria. Diagnoses of hypertension, dyslipidemia, and micro-/macroalbuminuria were obtained from medical records. Logistic and linear regression models were used to assess factors associated with weight status.

RESULTS

Of the 11,348 participants, 22 % were overweight and 14 % obese. Hypertension and dyslipidemia were diagnosed in 1.0 % and 3.8 % of participants, respectively; micro-/macroalbuminuria was diagnosed in 3.8 % of participants with available data (n = 7,401). The odds of either hypertension or dyslipidemia were higher in obese than healthy weight participants [OR 3.5, 99 % confidence interval (CI) 2.0-6.1 and 2.2, 99 % CI 1.6-3.1, respectively]. Obese participants tended to be diagnosed with micro-/macroalbuminuria less often than healthy weight participants (OR 0.6, 99 % CI 0.4-1.0).

CONCLUSIONS

Obese children with type 1 diabetes have a higher prevalence of hypertension and dyslipidemia than healthy weight children with type 1 diabetes. The possible association of obesity with lower micro-/macroalbuminuria rates warrants further investigation.

Matrix solid-phase dispersion extraction procedure for multiresidue pesticide analysis in oranges

A multiresidue extraction method based on matrix solid-phase dispersion (MSPD) is optimized for the extraction and gas chromatographic screening of eighteen insecticides (aldrin, carbophenothion, captafol, chlorpyriphos, chlorfenvinphos, diazinon, dicofol, alpha-endosulfan, beta-endosulfan, ethion, fenitrothion, folpet, methidathion, malathion, methyl-azinphos, methyl-parathion, phosmet, and tetradifon) from oranges. After optimization of different parameters, such as type of solid phase used and the amount of solid phase or eluent, recoveries ranged from 67 to 102% with relative standard deviations ranging from 2 to 10%. The limits of detection, calculated as 3 times the baseline noise ranged from 2 to 171 micrograms/kg. These limits of detection were about 10 times lower than the maximum residue levels established by the European Community. Compared with classical methods, the described procedure is simple, less labour intensive and does not require preparation and maintenance of equipment. Troublesome emulsions, such as those frequently observed in liquid-liquid partitioning did not occur.

Prediction and prevention of type 1 diabetes: update on success of prediction and struggles at prevention

Type 1 diabetes mellitus (T1DM) is the archetypal example of a T cell-mediated autoimmune disease characterized by selective destruction of pancreatic β cells. The pathogenic equation for T1DM presents a complex interrelation of genetic and environmental factors, most of which have yet to be identified. On the basis of observed familial aggregation of T1DM, it is certain that there is a decided heritable genetic susceptibility for developing T1DM. The well-known association of T1DM with certain human histocompatibility leukocyte antigen (HLA) alleles of the major histocompatibility complex (MHC) was a major step toward understanding the role of inheritance in T1DM. Type 1 diabetes is a polygenic disease with a small number of genes having large effects (e.g., HLA) and a large number of genes having small effects. Risk of T1DM progression is conferred by specific HLA DR/DQ alleles [e.g., DRB1*03-DQB1*0201 (DR3/DQ2) or DRB1*04-DQB1*0302 (DR4/DQ8)]. In addition, the HLA allele DQB1*0602 is associated with dominant protection from T1DM in multiple populations. A concordance rate lower than 100% between monozygotic twins indicates a potential involvement of environmental factors on disease development. The detection of at least two islet autoantibodies in the blood is virtually pre-diagnostic for T1DM. The majority of children who carry these biomarkers, regardless of whether they have an a priori family history of the disease, will develop insulin-requiring diabetes. Facilitating pre-diagnosis is the timing of seroconversion which is most pronounced in the first 2 yr of life. Unfortunately the significant progress in improving prediction of T1DM has not yet been paralleled by safe and efficacious intervention strategies aimed at preventing the disease. Herein we summarize the chequered history of prediction and prevention of T1DM, describing successes and failures alike, and thereafter examine future trends in the exciting, partially explored field of T1DM prevention.

Pediatric Diabetes Consortium Type 1 Diabetes New Onset (NeOn) Study: factors associated with HbA1c levels one year after diagnosis

OBJECTIVE

To identify determinants of hemoglobin A1c (HbA1c) levels 1 yr after the diagnosis of type 1 diabetes (T1D) in participants in the Pediatric Diabetes Consortium (PDC) T1D New Onset (NeOn) Study.

RESEARCH DESIGN AND METHODS

Diabetes-specific as well as socioeconomic factors during the first year following diagnosis were analyzed in 857 participants (mean age 9.1 yrs, 51% female, 66% non-Hispanic White) not participating in an intervention study who had an HbA1c value at 12 months.

RESULT

Mean ± SD HbA1c at 1 yr was 62 ± 16 mmol/mol (7.8% ± 1.5). In univariate and multivariate analyses, clinical center, non-Hispanic White race, private health insurance, living with both parents, higher frequency of self-monitoring of blood glucose (SMBG), and lower insulin requirements were associated with lower HbA1c concentrations at 1 yr (p < 0.01). No association was found with gender, age, Tanner stage, body mass index (BMI), diabetic ketoacidosis (DKA) at onset, number of positive autoantibodies or HbA1c at onset, or number of visits to diabetes physician during the first year.

CONCLUSIONS

White race, higher socioeconomic status, two-parent household, more frequent SMBG, and low insulin requirements are associated with lower HbA1c concentration 1 yr after the onset of T1D in children.

Association of non-HLA genes with type 1 diabetes autoimmunity

Approximately 50% of the genetic risk for type 1 diabetes is attributable to the HLA region. We evaluated associations between candidate genes outside the HLA region-INS, cytotoxic T-lymphocyte-associated antigen (CTLA)-4, interleukin (IL)-4, IL-4R, and IL-13 and islet autoimmunity among children participating in the Diabetes Autoimmunity Study in the Young (DAISY). Children with persistent islet autoantibody positivity (n = 102, 38 of whom have already developed diabetes) and control subjects (n = 198) were genotyped for single nucleotide polymorphisms (SNPs) in the candidate genes. The INS-23Hph1 polymorphism was significantly associated with both type 1 diabetes (OR = 0.30; 95% CI 0.13-0.69) and persistent islet autoimmunity but in the latter, only in children with the HLA-DR3/4 genotype (0.40; 0.18-0.89). CTLA-4 promoter SNP was significantly associated with type 1 diabetes (3.52; 1.22-10.17) but not with persistent islet autoimmunity. Several SNPs in the IL-4 regulatory pathway appeared to have a predisposing effect for type 1 diabetes. Associations were found between both IL-4R haplotypes and IL-4-IL-13 haplotypes and persistent islet autoimmunity and type 1 diabetes. This study confirms the association between the INS and CTLA-4 loci and type 1 diabetes. Genes involved in the IL-4 regulatory pathway (IL-4, IL-4R, IL-13) may confer susceptibility or protection to type 1 diabetes depending on individual SNPs or specific haplotypes.

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.