Blood Monocyte Phenotype Is A Marker of Cardiovascular Risk in Type 2 Diabetes

BACKGROUND

Diabetes is a major risk factor for atherosclerotic cardiovascular diseases with a 2-fold higher risk of cardiovascular events in people with diabetes compared with those without. Circulating monocytes are inflammatory effector cells involved in both type 2 diabetes (T2D) and atherogenesis.

METHODS

We investigated the relationship between circulating monocytes and cardiovascular risk progression in people with T2D, using phenotypic, transcriptomic, and metabolomic analyses. cardiovascular risk progression was estimated with coronary artery calcium score in a cohort of 672 people with T2D.

RESULTS

Coronary artery calcium score was positively correlated with blood monocyte count and frequency of the classical monocyte subtype. Unsupervised k-means clustering based on monocyte subtype profiles revealed 3 main endotypes of people with T2D at varying risk of cardiovascular events. These observations were confirmed in a validation cohort of 279 T2D participants. The predictive association between monocyte count and major adverse cardiovascular events was validated through an independent prospective cohort of 757 patients with T2D. Integration of monocyte transcriptome analyses and plasma metabolomes showed a disruption of mitochondrial pathways (tricarboxylic acid cycle, oxidative phosphorylation pathway) that underlined a proatherogenic phenotype.

CONCLUSIONS

In this study, we provide evidence that frequency and monocyte phenotypic profile are closely linked to cardiovascular risk in patients with T2D. The assessment of monocyte frequency and count is a valuable predictive marker for risk of cardiovascular events in patients with T2D.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04353869.

An obesogenic diet increases atherosclerosis through promoting microbiota dysbiosis-induced gut lymphocyte trafficking into the periphery

Although high-fat diet (HFD)-induced gut microbiota dysbiosis is known to affect atherosclerosis, the underlying mechanisms remain to be fully explored. Here, we show that the progression of atherosclerosis depends on a gut microbiota shaped by an HFD but not a high-cholesterol (HC) diet and, more particularly, on low fiber (LF) intake. Mechanistically, gut lymphoid cells impacted by HFD- or LF-induced microbiota dysbiosis highly proliferate in mesenteric lymph nodes (MLNs) and migrate from MLNs to the periphery, which fuels T cell accumulation within atherosclerotic plaques. This is associated with the induction of mucosal addressin cell adhesion molecule 1 (MAdCAM-1) within plaques and the presence of enterotropic lymphocytes expressing β7 integrin. MLN resection or lymphocyte deficiency abrogates the pro-atherogenic effects of a microbiota shaped by LF. Our study shows a pathological link between a diet-shaped microbiota, gut immune cells, and atherosclerosis, suggesting that a diet-modulated microbiome might be a suitable therapeutic target to prevent atherosclerosis.

Genetic inhibition of CARD9 accelerates the development of atherosclerosis in mice through CD36 dependent-defective autophagy

Caspase recruitment-domain containing protein 9 (CARD9) is a key signaling pathway in macrophages but its role in atherosclerosis is still poorly understood. Global deletion of Card9 in Apoe-/- mice as well as hematopoietic deletion in Ldlr-/- mice increases atherosclerosis. The acceleration of atherosclerosis is also observed in Apoe-/-Rag2-/-Card9-/- mice, ruling out a role for the adaptive immune system in the vascular phenotype of Card9 deficient mice. Card9 deficiency alters macrophage phenotype through CD36 overexpression with increased IL-1β production, increased lipid uptake, higher cell death susceptibility and defective autophagy. Rapamycin or metformin, two autophagy inducers, abolish intracellular lipid overload, restore macrophage survival and autophagy flux in vitro and finally abolish the pro-atherogenic effects of Card9 deficiency in vivo. Transcriptomic analysis of human CARD9-deficient monocytes confirms the pathogenic signature identified in murine models. In summary, CARD9 is a key protective pathway in atherosclerosis, modulating macrophage CD36-dependent inflammatory responses, lipid uptake and autophagy.

Prevalence and Description of the Skin Reactions Associated with Adhesives in Diabetes Technology Devices in an Adult Population: Results of the CUTADIAB Study

Objective: The use of continuous glucose monitoring (CGM) systems and continuous subcutaneous insulin infusion (CSII) devices adhering to the skin can lead to skin reactions. The objective was to determine the prevalence and consequences of skin reactions at CGM or CSII sites in a large unbiased population. Research Design and Methods: This is a cross-sectional multicenter study. All adult patients with diabetes seen in consultation over a period of 7 months and using or having used a system with skin adhesives (in the last 10 years) were included and filled out a self-assessment questionnaire. Results: Among 851 patients, skin reaction was reported in 28% with CGM and 29% with CSII. Patients reporting reactions were more frequently women using CGM and CSII, and CGM users had type 1 more often than type 2 diabetes (P < 0.001). Manifestations were similar for reactions to CGM and CSII: redness and pruritus in 70%-75% of patients with reactions, pain in 20%-25%, and vesicles and desquamation in 12%-15%. Manifestations occurred within the first 24 h of first use in 22%-24% of patients with reactions to CGM and CSII, but after more than 6 months in 38% and 47% of patients with reactions to CGM and CSII, respectively. Device use was definitively stopped in 12% of patients with reactions to CGM (3.2% of all users) and 7% with reactions to CSII (2.1% of all users). Conclusions: Skin reactions were common, with similar presentations in CGM and CSII users. Manifestations suggested skin irritation rather than allergies. These reactions rarely led to the definitive discontinuation of the use of the device.

JAK2V617F mutation drives vascular resident macrophages toward a pathogenic phenotype and promotes dissecting aortic aneurysm

JAK2V617F mutation is associated with an increased risk for athero-thrombotic cardiovascular disease, but its role in aortic disease development and complications remains unknown. In a cohort of patients with myeloproliferative neoplasm, JAK2V617F mutation was identified as an independent risk factor for dilation of both the ascending and descending thoracic aorta. Using single-cell RNA-seq, complementary genetically-modified mouse models, as well as pharmacological approaches, we found that JAK2V617F mutation was associated with a pathogenic pro-inflammatory phenotype of perivascular tissue-resident macrophages, which promoted deleterious aortic wall remodeling at early stages, and dissecting aneurysm through the recruitment of circulating monocytes at later stages. Finally, genetic manipulation of tissue-resident macrophages, or treatment with a Jak2 inhibitor, ruxolitinib, mitigated aortic wall inflammation and reduced aortic dilation and rupture. Overall, JAK2V617F mutation drives vascular resident macrophages toward a pathogenic phenotype and promotes dissecting aortic aneurysm.

Early macrophage response to obesity encompasses Interferon Regulatory Factor 5 regulated mitochondrial architecture remodelling

Adipose tissue macrophages (ATM) adapt to changes in their energetic microenvironment. Caloric excess, in a range from transient to diet-induced obesity, could result in the transition of ATMs from highly oxidative and protective to highly inflammatory and metabolically deleterious. Here, we demonstrate that Interferon Regulatory Factor 5 (IRF5) is a key regulator of macrophage oxidative capacity in response to caloric excess. ATMs from mice with genetic-deficiency of Irf5 are characterised by increased oxidative respiration and mitochondrial membrane potential. Transient inhibition of IRF5 activity leads to a similar respiratory phenotype as genomic deletion, and is reversible by reconstitution of IRF5 expression. We find that the highly oxidative nature of Irf5-deficient macrophages results from transcriptional de-repression of the mitochondrial matrix component Growth Hormone Inducible Transmembrane Protein (GHITM) gene. The Irf5-deficiency-associated high oxygen consumption could be alleviated by experimental suppression of Ghitm expression. ATMs and monocytes from patients with obesity or with type-2 diabetes retain the reciprocal regulatory relationship between Irf5 and Ghitm. Thus, our study provides insights into the mechanism of how the inflammatory transcription factor IRF5 controls physiological adaptation to diet-induced obesity via regulating mitochondrial architecture in macrophages.

Interferon Regulatory Factor 5 levels have been shown to increase in adipose tissue macrophages in diet-induced obesity. Here authors show that IRF5 transcriptionally represses the Growth Hormone Inducible Transmembrane Protein gene encoding a mitochondrial protein important for oxidative respiration in macrophages, thus driving the detrimental metabolic changes observed in obesity.

Diabetes Increases Severe COVID-19 Outcomes Primarily in Younger Adults

CONTEXT

Diabetes is reported as a risk factor for severe coronavirus disease 2019 (COVID-19), but whether this risk is similar in all categories of age remains unclear.

OBJECTIVE

To investigate the risk of severe COVID-19 outcomes in hospitalized patients with and without diabetes according to age categories.

DESIGN SETTING AND PARTICIPANTS

We conducted a retrospective observational cohort study of 6314 consecutive patients hospitalized for COVID-19 between February and 30 June 2020 in the Paris metropolitan area, France; follow-up was recorded until 30 September 2020.

MAIN OUTCOME MEASURE(S)

The main outcome was a composite outcome of mortality and orotracheal intubation in subjects with diabetes compared with subjects without diabetes, after adjustment for confounding variables and according to age categories.

RESULTS

Diabetes was recorded in 39% of subjects. Main outcome was higher in patients with diabetes, independently of confounding variables (hazard ratio [HR] 1.13 [1.03-1.24]) and increased with age in individuals without diabetes, from 23% for those <50 to 35% for those >80 years but reached a plateau after 70 years in those with diabetes. In direct comparison between patients with and without diabetes, diabetes-associated risk was inversely proportional to age, highest in <50 years and similar after 70 years. Similarly, mortality was higher in patients with diabetes (26%) than in those without diabetes (22%, P < 0.001), but adjusted HR for diabetes was significant only in patients younger than age 50 years (HR 1.81 [1.14-2.87]).

CONCLUSIONS

Diabetes should be considered as an independent risk factor for the severity of COVID-19 in young adults more so than in older adults, especially for individuals younger than 70 years.

Prognostic transcriptome classes of duodenopancreatic neuroendocrine tumors

Duodenopancreatic neuroendocrine tumors (DPNETs) aggressiveness is heterogeneous. Tumor grade and extension are commonly used for prognostic determination. Yet, grade classes are empirically defined, with regular updates changing the definition of classes. Genomic screening may provide more objective classes and reflect tumor biology. The aim of this study was to provide a transcriptome classification of DPNETs. We included 66 DPNETs, covering the entire clinical spectrum of the disease in terms of secretion, grade, and stage. Three distinct molecular groups were identified, associated with distinct outcomes (log-rank P < 0.01): (i) better-outcome DPNETs with pancreatic beta-cell signature. This group was mainly composed of well-differentiated, grade 1 insulinomas; (ii) poor-outcome DPNETs with pancreatic alpha-cell and hepatic signature. This group included all neuroendocrine carcinomas and grade 3 DPNETs, but also some grade 1 and grade 2 DPNETs and (iii) intermediate-outcome DPNETs with pancreatic exocrine and progenitor signature. This group included grade 1 and grade 2 DPNETs, with some insulinomas. Fibrinogen gene FGA expression was one of the topmost expressed liver genes. FGA expression was associated with disease-free survival (HR = 1.13, P = 0.005) and could be validated on two independent cohorts. This original pathophysiologic insight provides new prognostic classification perspectives.

Monocytopenia, monocyte morphological anomalies and hyperinflammation characterise severe COVID-19 in type 2 diabetes

Early in the COVID-19 pandemic, type 2 diabetes (T2D) was marked as a risk factor for severe disease and mortality. Inflammation is central to the aetiology of both conditions where variations in immune responses can mitigate or aggravate disease course. Identifying at-risk groups based on immunoinflammatory signatures is valuable in directing personalised care and developing potential targets for precision therapy. This observational study characterised immunophenotypic variation associated with COVID-19 severity in T2D. Broad-spectrum immunophenotyping quantified 15 leucocyte populations in peripheral circulation from a cohort of 45 hospitalised COVID-19 patients with and without T2D. Lymphocytopenia and specific loss of cytotoxic CD8+ lymphocytes were associated with severe COVID-19 and requirement for intensive care in both non-diabetic and T2D patients. A morphological anomaly of increased monocyte size and monocytopenia restricted to classical CD14Hi CD16- monocytes was specifically associated with severe COVID-19 in patients with T2D requiring intensive care. Increased expression of inflammatory markers reminiscent of the type 1 interferon pathway (IL6, IL8, CCL2, INFB1) underlaid the immunophenotype associated with T2D. These immunophenotypic and hyperinflammatory changes may contribute to increased voracity of COVID-19 in T2D. These findings allow precise identification of T2D patients with severe COVID-19 as well as provide evidence that the type 1 interferon pathway may be an actionable therapeutic target for future studies.

Regulation of inflammation in diabetes: From genetics to epigenomics evidence

Background

Diabetes is one of the greatest public health challenges worldwide, and we still lack complementary approaches to significantly enhance the efficacy of preventive and therapeutic approaches. Genetic and environmental factors are the culprits involved in diabetes risk. Evidence from the last decade has highlighted that deregulation in the immune and inflammatory responses increase susceptibility to type 1 and type 2 diabetes. Spatiotemporal patterns of gene expression involved in immune cell polarisation depend on genomic enhancer elements in response to inflammatory and metabolic cues. Several studies have reported that most regulatory genetic variants are located in the non-protein coding regions of the genome and particularly in enhancer regions. The progress of high-throughput technologies has permitted the characterisation of enhancer chromatin properties. These advances support the concept that genetic alteration of enhancers may influence the immune and inflammatory responses in relation to diabetes.

Scope of review

Results from genome-wide association studies (GWAS) combined with functional and integrative analyses have elucidated the impacts of some diabetes risk-associated variants that are involved in the regulation of the immune system. Additionally, genetic variant mapping to enhancer regions may alter enhancer status, which in turn leads to aberrant expression of inflammatory genes associated with diabetes susceptibility. The focus of this review was to provide an overview of the current indications that inflammatory processes are regulated at the genetic and epigenomic levels in diabetes, along with perspectives on future research avenues that may improve understanding of the disease.

Major conclusions

In this review, we provide genetic evidence in support of a deregulated immune response as a risk factor in diabetes. We also argue about the importance of enhancer regions in the regulation of immune cell polarisation and how the recent advances using genome-wide methods for enhancer identification have enabled the determination of the impact of enhancer genetic variation on diabetes onset and phenotype. This could eventually lead to better management plans and improved treatment responses in human diabetes.

Anaemia and its risk factors and association with treatments in patients with diabetes: A cross-sectional study

BACKGROUND

Anaemia is frequently seen in patients with diabetes and the main cause is renal failure. At all stages of renal failure, however, the prevalence of anaemia is higher in diabetes patients than expected for their glomerular filtration rate, suggesting that causes of anaemia other than renal failure are at work. The present cross-sectional study was conducted to investigate the possible iatrogenic causes of anaemia in patients with diabetes.

SUBJECTS AND METHODS

This was a hospital-based cross-sectional study of all patients who had biological and clinical data covering a 2-year period. All had been in contact with the diabetes department either as outpatients or as inpatients mostly for educational purposes. Clinical factors, including type of diabetes, known diabetes complications, treatments received and biological data, were reviewed for their possible involvement in anaemia.

RESULTS

A total of 4145 consecutive patients were included. Anaemia was observed in 1065 (25.7%) of them. Patients with anaemia were more frequently women and those with longer durations of diabetes. Haemoglobin concentrations were decreased, and prevalence of anaemia was increased at all stages of renal failure, already at stage 2, KDIGO classification. Anaemia patients were more frequently taking insulin, antiplatelet agents and renin-angiotensin system blockers (RASBs). After exclusion of patients with specific causes of anaemia, logistic regression analysis of all parameters correlated with anaemia on univariate analysis revealed that anaemia was associated with gender, antiplatelet agents and RASBs.

CONCLUSION

This study has confirmed that anaemia is frequently seen in diabetes patients and strongly associated with renal failure (already at stage 2). Our observations highlight the adjuvant role of drugs, particularly RASBs, in the risk of anaemia in patients with diabetes.

The RB gene family controls the maturation state of the EndoC-βH2 human pancreatic β-cells

The functional maturation of human pancreatic β-cells remains poorly understood. EndoC-βH2 is a human β-cell line with a reversible immortalized phenotype. Removal of the two oncogenes, SV40LT and hTERT introduced for its propagation, stops proliferation, triggers cell size increase and senescence, promotes mitochondrial activity and amplifies several β-cell traits and functions. Overall, these events recapitulate several aspects of functional β-cell maturation. We report here that selective depletion of SV40LT, but not of hTERT, is sufficient to revert EndoC-βH2 immortalization. SV40LT inhibits the activity of the RB family members and of P53. In EndoC-βH2 cells, the knock-down of RB itself, and, to a lesser extent, of its relative P130, precludes most events triggered by SV40LT depletion. In contrast, the knock-down of P53 does not prevent reversion of immortalization. Thus, an increase in RB and P130 activity, but not in P53 activity, is required for functional maturation of EndoC-βH2 cells upon SV40LT-depletion. In addition, RB and/or P130 depletion in SV40LT-expressing EndoC-βH2 cells decreases cell size, stimulates proliferation, and decreases the expression of key β-cell genes. Thus, despite SV40LT expression, EndoC-βH2 cells have a residual RB activity, which when suppressed reverts them to a more immature phenotype. These results show that the expression and activity levels of RB family members, especially RB itself, regulate the maturation state of EndoC-βH2 cells.

Pangenomic Classification of Pituitary Neuroendocrine Tumors

Pituitary neuroendocrine tumors (PitNETs) are common, with five main histological subtypes: lactotroph, somatotroph, and thyrotroph (POU1F1/PIT1 lineage); corticotroph (TBX19/TPIT lineage); and gonadotroph (NR5A1/SF1 lineage). We report a comprehensive pangenomic classification of PitNETs. PitNETs from POU1F1/PIT1 lineage showed an epigenetic signature of diffuse DNA hypomethylation, with transposable elements expression and chromosomal instability (except for GNAS-mutated somatotrophs). In TPIT lineage, corticotrophs were divided into three classes: the USP8-mutated with overt secretion, the USP8-wild-type with increased invasiveness and increased epithelial-mesenchymal transition, and the large silent tumors with gonadotroph transdifferentiation. Unexpected expression of gonadotroph markers was also found in GNAS-wild-type somatotrophs (SF1 expression), challenging the current definition of SF1/gonadotroph lineage. This classification improves our understanding and affects the clinical stratification of patients with PitNETs.

Conventional and Neo-antigenic Peptides Presented by β Cells Are Targeted by Circulating Naïve CD8+ T Cells in Type 1 Diabetic and Healthy Donors

Although CD8⁺ T-cell-mediated autoimmune β cell destruction occurs in type 1 diabetes (T1D), the target epitopes processed and presented by β cells are unknown. To identify them, we combined peptidomics and transcriptomics strategies. Inflammatory cytokines increased peptide presentation in vitro, paralleling upregulation of human leukocyte antigen (HLA) class I expression. Peptide sources featured several insulin granule proteins and all known β cell antigens, barring islet-specific glucose-6-phosphatase catalytic subunit-related protein. Preproinsulin yielded HLA-A2-restricted epitopes previously described. Secretogranin V and its mRNA splice isoform SCG5-009, proconvertase-2, urocortin-3, the insulin gene enhancer protein ISL-1, and an islet amyloid polypeptide transpeptidation product emerged as antigens processed into HLA-A2-restricted epitopes, which, as those already described, were recognized by circulating naive CD8⁺ T cells in T1D and healthy donors and by pancreas-infiltrating cells in T1D donors. This peptidome opens new avenues to understand antigen processing by β cells and for the development of T cell biomarkers and tolerogenic vaccination strategies.

[Diagnostic circumstances and clinical forms of type 1 diabetes]

Diagnostic circumstances and clinical forms of type 1 diabetes. In its classic form, type 1 diabetes is the prototype of insulindependent diabetes. But ketoacidosis can occur outside of type 1 diabetes, so ketoacdosis does not necessarily mean definitive insulin therapy. Conversely, type 1 diabetes may initially be mistaken for type 2 diabetes. This is often associated with insulin delay after months of wandering and poor blood glucose control. New forms of diabetes have appeared, such as fulminant diabetes, specific to individuals from South Asia and the Far East, but also iatrogenic forms associated with new immunomodulatory treatments that revolutionize the management of certain cancers. This review presents the clinic and differential diagnosis of type 1 diabetes including these new forms of diabetes.

Modeling human pancreatic beta cell dedifferentiation

OBJECTIVE

Dedifferentiation could explain reduced functional pancreatic β-cell mass in type 2 diabetes (T2D).

METHODS

Here we model human β-cell dedifferentiation using growth factor stimulation in the human β-cell line, EndoC-βH1, and human pancreatic islets.

RESULTS

Fibroblast growth factor 2 (FGF2) treatment reduced expression of β-cell markers, (INS, MAFB, SLC2A2, SLC30A8, and GCK) and activated ectopic expression of MYC, HES1, SOX9, and NEUROG3. FGF2-induced dedifferentiation was time- and dose-dependent and reversible upon wash-out. Furthermore, FGF2 treatment induced expression of TNFRSF11B, a decoy receptor for RANKL and protected β-cells against RANKL signaling. Finally, analyses of transcriptomic data revealed increased FGF2 expression in ductal, endothelial, and stellate cells in pancreas from T2D patients, whereas FGFR1, SOX,9 and HES1 expression increased in islets from T2D patients.

CONCLUSIONS

We thus developed an FGF2-induced model of human β-cell dedifferentiation, identified new markers of dedifferentiation, and found evidence for increased pancreatic FGF2, FGFR1, and β-cell dedifferentiation in T2D.

Virus-like infection induces human β cell dedifferentiation

Type 1 diabetes (T1D) is a chronic disease characterized by an autoimmune-mediated destruction of insulin-producing pancreatic β cells. Environmental factors such as viruses play an important role in the onset of T1D and interact with predisposing genes. Recent data suggest that viral infection of human islets leads to a decrease in insulin production rather than β cell death, suggesting loss of β cell identity. We undertook this study to examine whether viral infection could induce human β cell dedifferentiation. Using the functional human β cell line EndoC-βH1, we demonstrate that polyinosinic-polycytidylic acid (PolyI:C), a synthetic double-stranded RNA that mimics a byproduct of viral replication, induces a decrease in β cell-specific gene expression. In parallel with this loss, the expression of progenitor-like genes such as SOX9 was activated following PolyI:C treatment or enteroviral infection. SOX9 was induced by the NF-κB pathway and also in a paracrine non-cell-autonomous fashion through the secretion of IFN-α. Lastly, we identified SOX9 targets in human β cells as potentially new markers of dedifferentiation in T1D. These findings reveal that inflammatory signaling has clear implications in human β cell dedifferentiation.

Decreased α-cell mass and early structural alterations of the exocrine pancreas in patients with type 1 diabetes: An analysis based on the nPOD repository

Background and aims

Abnormal glucagon secretion and functional alterations of the exocrine pancreas have been described in patients with type 1 diabetes (T1D), but their respective anatomical substrata have seldom been investigated. Our aim was to develop an automated morphometric analysis process to characterize the anatomy of α-cell and exocrine pancreas in patients with T1D, using the publicly available slides of the Network for Pancreatic Organ Donors (nPOD).

Materials and methods

The ratio of β- and α-cell area to total tissue area were quantified in 75 patients with T1D (thereafter patients) and 66 control subjects (thereafter controls), on 2 insulin-stained and 4 glucagon-stained slides from both the head and the tail of the pancreas. The β- and α-cell masses were calculated in the 66 patients and the 50 controls for which the pancreas weight was available. Non-exocrine-non-endocrine tissue area (i.e. non-acinar, non-insular tissue) to total tissue area ratio was evaluated on both insulin- and glucagon-stained slides. Results were expressed as mean ±SD.

Results

An automated quantification method was set up using the R software and was validated by quantification of β-cell mass, a well characterized parameter. β-cell mass was 29.6±112 mg in patients and 628 ±717 mg in controls (p<0.0001). α-cell mass was 181±176 mg in patients and 349 ±241mg in controls (p<0.0001). Non-exocrine-non-endocrine area to total tissue area ratio was 39±9% in patients and 29± 10% in controls (p<0.0001) and increased with age in both groups, with no correlation with diabetes duration in patients.

Conclusion

The absolute α-cell mass was lower in patients compared to controls, in proportion to the decrease in pancreas weight observed in patients. Non-exocrine-non-endocrine area to total tissue area ratio increased with age in both groups but was higher in patients at all ages.

β-cell Mass in Nondiabetic Autoantibody-Positive Subjects: An Analysis Based on the Network for Pancreatic Organ Donors Database

CONTEXT

Little information is available about β-cell mass in antibody-positive (Ab+) nondiabetic subjects.

OBJECTIVE

We have investigated whether the publicly available virtual slides of the Network for Pancreatic Organ Donors with Diabetes (nPOD) project can be used to assess β-cell mass and distribution in nondiabetic antibody-negative (Ab−) and antibody-positive (Ab+) subjects and in patients with recent-onset type 1 diabetes (T1D).

SUBJECTS AND METHODS

We developed a semi-automated quantification method and applied it to 415 insulin-stained slides from 69 Ab− subjects, 101 slides from 18 Ab+ subjects, and 46 slides from eight recent-onset (<3 y) T1D subjects. Among these subjects, 48, 17, and seven had an available pancreatic mass, respectively, and were used for the quantification of β-cell mass.

RESULTS

In Ab− subjects, the β-cell and endocrine mass were 0.66 ± 0.42 and 1.0 ± 0.65 g, respectively. Nonexocrine tissue represented 29% of pancreatic area, a proportion that increased with age. Proportional β-cell area relative to total pancreatic area was higher in the tail compared with head (0.83 vs 0.71%; P < .001). In Ab+ subjects, β-cell mass and β-cell area were similar to those of Ab− individuals, whereas these parameters were dramatically decreased in recent-onset T1D patients.

CONCLUSION

The virtual slides of the nPOD project can be used for quantification projects. In Ab+ nondiabetic subjects, the β-cell mass was not decreased. However, as this cohort is largely composed of donors from the general population, with a single autoantibody, future studies with a larger number of donors with multiple autoantibodies and predisposing human leucocyte antigen genes are required to better define the dynamics of β-cell destruction in the preclinical phases of T1D.

Xenotropic retrovirus Bxv1 in human pancreatic β cell lines

It has been reported that endogenous retroviruses can contaminate human cell lines that have been passaged as xenotransplants in immunocompromised mice. We previously developed and described 2 human pancreatic β cell lines (EndoC-βH1 and EndoC-βH2) that were generated in this way. Here, we have shown that B10 xenotropic virus 1 (Bxv1), a xenotropic endogenous murine leukemia virus (MuLV), is present in these 2 recently described cell lines. We determined that Bxv1 was also present in SCID mice that were used for in vivo propagation of EndoC-βH1/2 cells, suggesting that contamination occurred during xenotransplantation. EndoC-βH1/2 cells released Bxv1 particles that propagated to human 293T and Mus dunni cells. Mobilization assays demonstrated that Bxv1 transcomplements defective MuLV-based retrovectors. In contrast, common rodent β cell lines, rat INS-1E and RIN-5F cells and mouse MIN6 and βTC3 cells, displayed either no or extremely weak xenotropic helper activity toward MuLV-based retrovectors, although xenotropic retrovirus sequences and transcripts were detected in both mouse cell lines. Bxv1 propagation from EndoC-βH1/2 to 293T cells occurred only under optimized conditions and was overall poorly efficient. Thus, although our data imply that MuLV-based retrovectors should be cautiously used in EndoC-βH1/2 cells, our results indicate that an involuntary propagation of Bxv1 from these cells can be easily avoided with good laboratory practices.