Fulminant type 1 diabetes: Focusing on triggering factors.

Fulminant type 1 diabetes (FT1D) is a novel type of type 1 diabetes that is caused by extremely rapid destruction of the pancreatic ß cells. Early diagnosis or prediction of FT1D is critical for the prevention or timely treatment of diabetes ketoacidosis, which can be life-threatening. Understanding its triggers or promoting factors plays an important role in the prevention and treatment of FT1D. In this review, we summarised the various triggering factors of FT1D, including susceptibility genes, immunological factors (cellular and humoural immunity), immune checkpoint inhibitor therapies, drug reactions with eosinophilia and systemic symptoms or drug-induced hypersensitivity syndrome, pregnancy, viral infections, and vaccine inoculation. This review provides the basis for future research into the pathogenetic mechanisms that regulate FT1D development and progression to further improve the prognosis and clinical management of patients with FT1D.

Apolipoprotein L genes are novel mediators of inflammation in beta cells.

AIMS/HYPOTHESIS: Inflammation induces beta cell dysfunction and demise but underlying molecular mechanisms remain unclear. The apolipoprotein L (APOL) family of genes has been associated with innate immunity and apoptosis in non-pancreatic cell types, but also with metabolic syndrome and type 2 diabetes mellitus. Here, we hypothesised that APOL genes play a role in inflammation-induced beta cell damage. METHODS: We used single-cell transcriptomics datasets of primary human pancreatic islet cells to study the expression of APOL genes upon specific stress conditions. Validation of the findings was carried out in EndoC-ßH1 cells and primary human islets. Finally, we performed loss- and gain-of-function experiments to investigate the role of APOL genes in beta cells. RESULTS: APOL genes are expressed in primary human beta cells and APOL1, 2 and 6 are strongly upregulated upon inflammation via the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway. APOL1 overexpression increases endoplasmic reticulum stress while APOL1 knockdown prevents cytokine-induced beta cell death and interferon-associated response. Furthermore, we found that APOL genes are upregulated in beta cells from donors with type 2 diabetes compared with donors without diabetes mellitus. CONCLUSIONS/INTERPRETATION: APOLs are novel regulators of islet inflammation and may contribute to beta cell damage during the development of diabetes. DATA AVAILABILITY: scRNAseq data generated by our laboratory and used in this study are available in the Gene Expression Omnibus (GEO; www.ncbi.nlm.nih.gov/geo/ ), accession number GSE218316.

Imaging in Type 1 Diabetes, Current Perspectives and Directions.

Type 1 diabetes (T1D) is characterized by the autoimmune-mediated attack of insulin-producing beta cells in the pancreas, leading to reliance on exogenous insulin to control a patient's blood glucose levels. As progress is being made in understanding the pathophysiology of the disease and how to better develop therapies to treat it, there is an increasing need for monitoring technologies to quantify beta cell mass and function throughout T1D progression and beta cell replacement therapy. Molecular imaging techniques offer a possible solution through both radiologic and non-radiologic means including positron emission tomography, magnetic resonance imaging, electron paramagnetic resonance imaging, and spatial omics. This commentary piece outlines the role of molecular imaging in T1D research and highlights the need for further applications of such methodologies in T1D.

The pathogenic "symphony" in type 1 diabetes: A disorder of the immune system, ß cells, and exocrine pancreas.

Type 1 diabetes (T1D) is widely considered to result from the autoimmune destruction of insulin-producing ß cells. This concept has been a central tenet for decades of attempts seeking to decipher the disorder's pathogenesis and prevent/reverse the disease. Recently, this and many other disease-related notions have come under increasing question, particularly given knowledge gained from analyses of human T1D pancreas. Perhaps most crucial are findings suggesting that a collective of cellular constituents-immune, endocrine, and exocrine in origin-mechanistically coalesce to facilitate T1D. This review considers these emerging concepts, from basic science to clinical research, and identifies several key remaining knowledge voids.

The countdown to type 1 diabetes: when, how and why does the clock start?

'The clock to type 1 diabetes has started when islet antibodies are first detected', commented George Eisenbarth with regard to the pathogenesis of type 1 diabetes. This review focuses on 'starting the clock', i.e. the initiation of pre-symptomatic islet autoimmunity/the first appearance of islet autoantibodies. In particular, this review addresses why susceptibility to developing islet autoimmunity is greatest in the first 2 years of life and why beta cells are a frequent target of the immune system during this fertile period. A concept for the development of beta cell autoimmunity in childhood is discussed and three factors are highlighted that contribute to this early predisposition: (1) high beta cell activity and potential vulnerability to stress; (2) high rates of and first exposures to infection; and (3) a heightened immune response, with a propensity for T helper type 1 (Th1) immunity. Arguments are presented that beta cell injury, accompanied by activation of an inflammatory immune response, precedes the initiation of autoimmunity. Finally, the implications for strategies aimed at primary prevention for a world without type 1 diabetes are discussed.

Pharmacological inhibitors of ß-cell dysfunction and death as therapeutics for diabetes.

More than 500 million adults suffer from diabetes worldwide, and this number is constantly increasing. Diabetes causes 5 million deaths per year and huge healthcare costs per year. ß-cell death is the major cause of type 1 diabetes. ß-cell secretory dysfunction plays a key role in the development of type 2 diabetes. A loss of ß-cell mass due to apoptotic death has also been proposed as critical for the pathogenesis of type 2 diabetes. Death of ß-cells is caused by multiple factors including pro-inflammatory cytokines, chronic hyperglycemia (glucotoxicity), certain fatty acids at high concentrations (lipotoxicity), reactive oxygen species, endoplasmic reticulum stress, and islet amyloid deposits. Unfortunately, none of the currently available antidiabetic drugs favor the maintenance of endogenous ß-cell functional mass, indicating an unmet medical need. Here, we comprehensively review over the last ten years the investigation and identification of molecules of pharmacological interest for protecting ß-cells against dysfunction and apoptotic death which could pave the way for the development of innovative therapies for diabetes.

Non-invasive imaging of functional pancreatic islet beta-cell mass in people with type 1 diabetes mellitus.

AIMS: To investigate whether manganese-enhanced magnetic resonance imaging can assess functional pancreatic beta-cell mass in people with type 1 diabetes mellitus. METHODS: In a prospective case-control study, 20 people with type 1 diabetes mellitus (10 with low (≥50 pmol/L) and 10 with very low (<50 pmol/L) C-peptide concentrations) and 15 healthy volunteers underwent manganese-enhanced magnetic resonance imaging of the pancreas following an oral glucose load. Scan-rescan reproducibility was performed in 10 participants. RESULTS: Mean pancreatic manganese uptake was 31 ± 6 mL/100 g of tissue/min in healthy volunteers (median 32 [interquartile range 23-36] years, 6 women), falling to 23 ± 4 and 13 ± 5 mL/100 g of tissue/min (p ≤ 0.002 for both) in people with type1 diabetes mellitus (52 [44-61] years, 6 women) and low or very low plasma C-peptide concentrations respectively. Pancreatic manganese uptake correlated strongly with plasma C-peptide concentrations in people with type1 diabetes mellitus (r = 0.73, p < 0.001) but not in healthy volunteers (r = -0.054, p = 0.880). There were no statistically significant correlations between manganese uptake and age, body-mass index, or glycated haemoglobin. There was strong intra-observer (mean difference: 0.31 (limits of agreement -1.42 to 2.05) mL/100 g of tissue/min; intra-class correlation, ICC = 0.99), inter-observer (-1.23 (-5.74 to 3.27) mL/100 g of tissue/min; ICC = 0.85) and scan-rescan (-0.72 (-2.9 to 1.6) mL/100 g of tissue/min; ICC = 0.96) agreement for pancreatic manganese uptake. CONCLUSIONS: Manganese-enhanced magnetic resonance imaging provides a potential reproducible non-invasive measure of functional beta-cell mass in people with type 1 diabetes mellitus. This holds major promise for investigating type 1 diabetes, monitoring disease progression and assessing novel immunomodulatory interventions.

GLP-1R agonists demonstrate potential to treat Wolfram syndrome in human preclinical models.

AIMS/HYPOTHESIS: Wolfram syndrome is a rare autosomal recessive disorder caused by pathogenic variants in the WFS1 gene. It is characterised by insulin-dependent diabetes mellitus, optic nerve atrophy, diabetes insipidus, hearing loss and neurodegeneration. Considering the unmet treatment need for this orphan disease, this study aimed to evaluate the therapeutic potential of glucagon-like peptide 1 receptor (GLP-1R) agonists under wolframin (WFS1) deficiency with a particular focus on human beta cells and neurons. METHODS: The effect of the GLP-1R agonists dulaglutide and exenatide was examined in Wfs1 knockout mice and in an array of human preclinical models of Wolfram syndrome, including WFS1-deficient human beta cells, human induced pluripotent stem cell (iPSC)-derived beta-like cells and neurons from control individuals and individuals affected by Wolfram syndrome, and humanised mice. RESULTS: Our study shows that the long-lasting GLP-1R agonist dulaglutide reverses impaired glucose tolerance in WFS1-deficient mice, and that exenatide and dulaglutide improve beta cell function and prevent apoptosis in different human WFS1-deficient models including iPSC-derived beta cells from people with Wolfram syndrome. Exenatide improved mitochondrial function, reduced oxidative stress and prevented apoptosis in Wolfram syndrome iPSC-derived neural precursors and cerebellar neurons. CONCLUSIONS/INTERPRETATION: Our study provides novel evidence for the beneficial effect of GLP-1R agonists on WFS1-deficient human pancreatic beta cells and neurons, suggesting that these drugs may be considered as a treatment for individuals with Wolfram syndrome.

Taurine reduces apoptosis mediated by endoplasmic reticulum stress in islet ß-cells induced by high-fat and -glucose diets.

Poor eating habits, especially high-fat and -glucose diets intake, can lead to endoplasmic reticulum (ER) stress in islet ß-cells, insulin resistance, and islet ß-cell dysfunction and cause islet ß-cell apoptosis, which leads to type 2 diabetes mellitus (T2DM). Taurine is a crucial amino acid in the human body. In this study, we aimed to explore the mechanism through which taurine reduces glycolipid toxicity. INS-1 islet ß-cell lines were cultured with a high concentration of fat and glucose. SD rats were fed a high-fat and -glucose diet. MTS, Transmission electron microscopy, Flow cytometry, Hematoxylin-eosin, TUNEL, Western blotting analysis and other methods were used to detect relevant indicators. The research found that taurine increases the cell activity, reduces the apoptosis rate, alleviates the structural changes of ER under high-fat and -glucose exposure models. In addition, taurine improves blood lipid content and islets pathological changes, regulates the relative protein expression in ER stress and apoptosis, increases the insulin sensitivity index (HOMA-IS), and reduces the insulin resistance index (HOMAC-IR) of SD rats fed with a high-fat and -glucose diet.

Obstructive sleep apnea (OSA) is associated with the impairment of beta-cell response to glucose in children and adolescents with obesity.

BACKGROUND: The main purpose of the study is to assess the association between obstructive sleep apnea (OSA) and insulin secretion in children with obesity. METHODS: We enrolled children and adolescents who attended our pediatric clinic because of obesity and OSA. Glucose homeostasis was assessed through standard 2-h oral glucose tolerance test (OGTT). Nocturnal cardio-respiratory polygraphy was performed for OSA diagnosis. Twenty-two patients underwent a 3-h OGTT to investigate insulin secretion and sensitivity through the oral-minimal model. RESULTS: seventy-seven children and adolescents were included in the study. Based on OSA severity, the cohort was divided into three groups (29 mild, 29 moderate, and 19 severe OSA). The group with mild OSA showed lower levels of 30-min glucose (p = 0.01) and 60-min glucose (p = 0.03), and lower prevalence of elevated 1-h glucose (10.4% versus 44.8% in moderate and 31.6% in severe OSA, p = 0.01). The odds for elevated 1-h plasma glucose was 6.2-fold (95%CI 1.6-23.4) higher in subjects with moderate and severe OSA compared to mild OSA (p = 0.007) independent of confounders. Spearman correlation test revealed a positive correlation between 30-min plasma glucose and apnea-hypopnea index (AHI, r = 0.31, p = 0.01), oxygen desaturation index (ODI, r = 0.31, p = 0.009), and mean desaturation (r = 0.25, p = 0.04). The 3-h OGTT study included 22 participants (7 mild, 9 moderate, and 6 severe OSA). The group with mild OSA showed a higher dynamic, static, and total insulin secretion compared to those with moderate and severe OSA (p < 0.0001, p = 0.007, p = 0.007, respectively). AHI was significantly correlated to dynamic insulin secretion (r = -0.48, p = 0.02). CONCLUSIONS: OSA might impair beta-cell function reducing the pool of promptly releasable insulin in children and adolescents with obesity, in the absence of an effect on insulin sensitivity.

An environmentally sensitive molecular rotor as a NIR fluorescent probe for the detection of islet amyloid polypeptide.

The deposits of human islet amyloid polypeptide (IAPP), also called amylin, in the pancreas have been postulated to be a factor of pancreatic ß-cell dysfunction and is one of the common pathological hallmarks of type II diabetes mellitus (T2DM). Therefore, it is imperative to gain an in-depth understanding of the formation of these aggregates. In this study, we demonstrate a rationally-designed strategy of an environmentally sensitive near-infrared (NIR) molecular rotor utilizing thioflavin T (ThT) as a scaffold for IAPP deposits. We extended the π delocalized system not only to improve the viscosity sensitivity but also to prolong the emission wavelength to the NIR region. A naphthalene moiety was also introduced to adjust the sensitivity of our designed probes to differentiate the binding microenvironment polarity of different targeted proteins. As a result, a novel NIR fluorogenic probe toward IAPP aggregates, namely AmySP-4-Nap-Ene, was first developed. When attached to different protein aggregates, this probe exhibited distinct fluorescence emission profiles. In a comparison with ThT, the fluorescence emission of non-ionic AmySP-4-Nap-Ene exhibits a significant difference between the presence of non-fibrillar and fibrillar IAPP and displays a higher binding affinity toward IAPP fibrils. Further, the AmySP-4-Nap-Ene can be utilized to monitor IAPP accumulating process and image fibrils both in vitro and in living cells.

Type 1 diabetes: what is the role of autoimmunity in ß cell death?

The current dogma of type 1 diabetes pathogenesis asserts that an autoimmune attack leads to the destruction of pancreatic ß cells, with subsequent hyperglycemia. This dogma is based on islet autoantibodies emerging prior to the onset of type 1 diabetes. In this issue of the JCI, Warncke et al. report on their investigation of the development of hyperglycemia below the diabetes threshold as an early proxy of ß cell demise. Surprisingly, they found that an elevation in blood glucose preceded the appearance of autoimmunity. This observation calls into question the importance of autoimmunity as the primary cause of ß cell destruction and has implications for prevention and treatment in diabetes.

Altered microvasculature in pancreatic islets from subjects with type 1 diabetes.

AIMS: The transcriptome of different dissociated pancreatic islet cells has been described in enzymatically isolated islets in both health and disease. However, the isolation, culturing, and dissociation procedures likely affect the transcriptome profiles, distorting the biological conclusions. The aim of the current study was to characterize the cells of the islets of Langerhans from subjects with and without type 1 diabetes in a way that reflects the in vivo situation to the highest possible extent. METHODS: Islets were excised using laser capture microdissection directly from frozen pancreatic tissue sections obtained from organ donors with (n = 7) and without (n = 8) type 1 diabetes. Transcriptome analysis of excised samples was performed using AmpliSeq. Consecutive pancreatic sections were used to estimate the proportion of beta-, alpha-, and delta cells using immunofluorescence and to examine the presence of CD31 positive endothelial regions using immunohistochemistry. RESULTS: The proportion of beta cells in islets from subjects with type 1 diabetes was reduced to 0% according to both the histological and transcriptome data, and several alterations in the transcriptome were derived from the loss of beta cells. In total, 473 differentially expressed genes were found in the islets from subjects with type 1 diabetes. Functional enrichment analysis showed that several of the most upregulated gene sets were related to vasculature and angiogenesis, and histologically, vascular density was increased in subjects with type 1 diabetes. Downregulated in type 1 diabetes islets was the gene set epithelial mesenchymal transition. CONCLUSION: A number of transcriptional alterations are present in islets from subjects with type 1 diabetes. In particular, several gene sets related to vasculature and angiogenesis are upregulated and there is an increased vascular density, suggesting an altered microvasculature in islets from subjects with type 1 diabetes. By studying pancreatic islets extracted directly from snap-frozen pancreatic tissue, this study reflects the in vivo situation to a high degree and gives important insights into islet pathophysiology in type 1 diabetes.

Nicotinamide riboside kinase 1 protects against diet and age-induced pancreatic ß-cell failure.

OBJECTIVE: Disturbances in NAD+ metabolism have been described as a hallmark for multiple metabolic and age-related diseases, including type 2 diabetes. While alterations in pancreatic ß-cell function are critical determinants of whole-body glucose homeostasis, the role of NAD+ metabolism in the endocrine pancreas remains poorly explored. Here, we aimed to evaluate the role of nicotinamide riboside (NR) metabolism in maintaining NAD+ levels and pancreatic ß-cell function in pathophysiological conditions. METHODS: Whole body and pancreatic ß-cell-specific NRK1 knockout (KO) mice were metabolically phenotyped in situations of high-fat feeding and aging. We also analyzed pancreatic ß-cell function, ß-cell mass and gene expression. RESULTS: We first demonstrate that NRK1, the essential enzyme for the utilization of NR, is abundantly expressed in pancreatic ß-cells. While NR treatment did not alter glucose-stimulated insulin secretion in pancreatic islets from young healthy mice, NRK1 knockout mice displayed glucose intolerance and compromised ß-cells response to a glucose challenge upon high-fat feeding or aging. Interestingly, ß cell dysfunction stemmed from the functional failure of other organs, such as liver and kidney, and the associated changes in circulating peptides and hormones, as mice lacking NRK1 exclusively in ß-cells did not show altered glucose homeostasis. CONCLUSIONS: This work unveils a new physiological role for NR metabolism in the maintenance of glucose tolerance and pancreatic ß-cell function in high-fat feeding or aging conditions.

3D chromatin maps of the human pancreas reveal lineage-specific regulatory architecture of T2D risk.

Three-dimensional (3D) chromatin organization maps help dissect cell-type-specific gene regulatory programs. Furthermore, 3D chromatin maps contribute to elucidating the pathogenesis of complex genetic diseases by connecting distal regulatory regions and genetic risk variants to their respective target genes. To understand the cell-type-specific regulatory architecture of diabetes risk, we generated transcriptomic and 3D epigenomic profiles of human pancreatic acinar, alpha, and beta cells using single-cell RNA-seq, single-cell ATAC-seq, and high-resolution Hi-C of sorted cells. Comparisons of these profiles revealed differential A/B (open/closed) chromatin compartmentalization, chromatin looping, and transcriptional factor-mediated control of cell-type-specific gene regulatory programs. We identified a total of 4,750 putative causal-variant-to-target-gene pairs at 194 type 2 diabetes GWAS signals using pancreatic 3D chromatin maps. We found that the connections between candidate causal variants and their putative target effector genes are cell-type stratified and emphasize previously underappreciated roles for alpha and acinar cells in diabetes pathogenesis.

Beta cell and immune cell interactions in autoimmune type 1 diabetes: How they meet and talk to each other.

BACKGROUND: The highly complex pathogenesis of Type 1 Diabetes is driven by several immune cell types with both effector and regulatory characteristics, which ultimately ends in the destruction of the insulin-producing beta cells. There are multiple layers of interaction between these immune cell populations and the pancreatic islets. SCOPE OF REVIEW: In this review article, we aim to discuss important recent insights into the multiple layers of interaction between immune cell populations and the pancreatic islets. Specifically, we discuss the environment where immune and beta cell interactions occur, the key cell types and molecules involved, and the outcomes of these interactions. MAJOR CONCLUSIONS: Most of the molecular mechanisms underlying aberrant immune cell activation and impaired immune tolerance remain insufficiently understood, which hinders the development of efficient prevention and treatment strategies. In order to overcome this knowledge gap, a better understanding of the complex interactions of immune cells and beta cells, including both the underlying protective and pathogenic mechanisms is urgently required.

The ß-Cell in Type 1 Diabetes Pathogenesis: A Victim of Circumstances or an Instigator of Tragic Events?

Recent reports have revived interest in the active role that ß-cells may play in type 1 diabetes pathogenesis at different stages of disease. In some studies, investigators suggested an initiating role and proposed that type 1 diabetes may be primarily a disease of ß-cells and only secondarily a disease of autoimmunity. This scenario is possible and invites the search for environmental triggers damaging ß-cells. Another major contribution of ß-cells may be to amplify autoimmune vulnerability and to eventually drive it into an intrinsic, self-detrimental state that turns the T cell-mediated homicide into a ß-cell suicide. On the other hand, protective mechanisms are also mounted by ß-cells and may provide novel therapeutic targets to combine immunomodulatory and ß-cell protective agents. This integrated view of autoimmunity as a disease of T-cell/ß-cell cross talk will ultimately advance our understanding of type 1 diabetes pathogenesis and improve our chances of preventing or reversing disease progression.

Persistent coxsackievirus B infection and pathogenesis of type 1 diabetes mellitus.

Enteroviruses are believed to trigger or accelerate islet autoimmunity in genetically susceptible individuals, thereby resulting in loss of functional insulin-producing ß-cells and type 1 diabetes mellitus (T1DM). Although enteroviruses are primarily involved in acute and lytic infections in vitro and in vivo, they can also establish a persistent infection. Prospective epidemiological studies have strongly associated the persistence of enteroviruses, especially coxsackievirus B (CVB), with the appearance of islet autoantibodies and an increased risk of T1DM. CVB can persist in pancreatic ductal and ß-cells, which leads to structural or functional alterations of these cells, and to a chronic inflammatory response that promotes recruitment and activation of pre-existing autoreactive T cells and ß-cell autoimmune destruction. CVB persistence in other sites, such as the intestine, blood cells and thymus, has been described; these sites could serve as a reservoir for infection or reinfection of the pancreas, and this persistence could have a role in the disturbance of tolerance to ß-cells. This Review addresses the involvement of persistent enterovirus infection in triggering islet autoimmunity and T1DM, as well as current strategies to control enterovirus infections for preventing or reducing the risk of T1DM onset.

MicroRNA-21 promotes pancreatic ß cell function through modulating glucose uptake.

Pancreatic ß cell dysfunction contributes to the pathogenesis of type 2 diabetes. MiR-21 has been shown to be induced in the islets of glucose intolerant patients and type 2 diabetic mice. However, the role of miR-21 in the regulation of pancreatic ß cell function remains largely elusive. In the current study, we identify the pathway by which miR-21 regulates glucose-stimulated insulin secretion utilizing mice lacking miR-21 in their ß cells (miR-21ßKO). We find that miR-21ßKO mice develop glucose intolerance due to impaired glucose-stimulated insulin secretion. Mechanistic studies reveal that miR-21 enhances glucose uptake and subsequently promotes insulin secretion by up-regulating Glut2 expression in a miR-21-Pdcd4-AP-1 dependent pathway. Over-expression of Glut2 in knockout islets results in rescue of the impaired glucose-stimulated insulin secretion. Furthermore, we demonstrate that delivery of miR-21 into the pancreas of type 2 diabetic db/db male mice is able to promote Glut2 expression and reduce blood glucose level. Taking together, our results reveal that miR-21 in islet ß cell promotes insulin secretion and support a role for miR-21 in the regulation of pancreatic ß cell function in type 2 diabetes.

Circulating C-Peptide Levels in Living Children and Young People and Pancreatic ß-Cell Loss in Pancreas Donors Across Type 1 Diabetes Disease Duration.

C-peptide declines in type 1 diabetes, although many long-duration patients retain low, but detectable levels. Histological analyses confirm that ß-cells can remain following type 1 diabetes onset. We explored the trends observed in C-peptide decline in the UK Genetic Resource Investigating Diabetes (UK GRID) cohort (N = 4,079), with ß-cell loss in pancreas donors from the network for Pancreatic Organ donors with Diabetes (nPOD) biobank and the Exeter Archival Diabetes Biobank (EADB) (combined N = 235), stratified by recently reported age at diagnosis endotypes (<7, 7-12, ≥13 years) across increasing diabetes durations. The proportion of individuals with detectable C-peptide declined beyond the first year after diagnosis, but this was most marked in the youngest age group (<1-year duration: age <7 years: 18 of 20 [90%], 7-12 years: 107 of 110 [97%], ≥13 years: 58 of 61 [95%] vs. 1-5 years postdiagnosis: <7 years: 172 of 522 [33%], 7-12 years: 604 of 995 [61%], ≥13 years: 225 of 289 [78%]). A similar profile was observed in ß-cell loss, with those diagnosed at younger ages experiencing more rapid loss of islets containing insulin-positive (insulin+) ß-cells <1 year postdiagnosis: age <7 years: 23 of 26 (88%), 7-12 years: 32 of 33 (97%), ≥13 years: 22 of 25 (88%) vs. 1-5 years postdiagnosis: <7 years: 1 of 12 (8.3%), 7-12 years: 7 of 13 (54%), ≥13 years: 7 of 8 (88%). These data should be considered in the planning and interpretation of intervention trials designed to promote ß-cell retention and function.