Pancreatic Islet Cells Research Articles

Effects of artemether on pancreatic islet morphology, islet cell turnover and α-cell transdifferentiation in insulin-deficient GluCreERT2;ROSA26-eYFP diabetic mice.

The antimalarial drug artemether is suggested to effect pancreatic islet cell transdifferentiation, presumably through activation γ-aminobutyric acid receptors, but this biological action is contested. We have investigated changes in α-cell lineage in response to 10-days treatment with artemether (100 mg/kg oral, once daily) on a background of β-cell stress induced by multiple low-dose streptozotocin (STZ) injection in GluCreERT2; ROSA26-eYFP transgenic mice. Artemether intervention did not affect the actions of STZ on body weight, food and fluid intake or blood glucose. Circulating insulin and glucagon were reduced by STZ treatment, with a corresponding decline in pancreatic insulin content, which were not altered by artemether. The detrimental changes to pancreatic islet morphology induced by STZ were also evident in artemether-treated mice. Tracing of α-cell lineage, through co-staining for glucagon and yellow fluorescent protein (YFP), revealed a significant decrease of the proportion of glucagon+YFP- cells in STZ-diabetic mice, which was reversed by artemether. However, artemether had no effect on transdifferentiation of α-cells into β-cells and failed to augment the number of bi-hormonal, insulin+glucagon+, islet cells. Our observations confirm that artemisinin derivatives do not impart meaningful benefits on islet cell lineage transition events or pancreatic islet morphology.

BRONCHOPULMONARY CARCINOID AND TYPE 1 MULTIPLE ENDOCRINE NEOPLASIA (MEN)

BRONCHOPULMONARY CARCINOID AND TYPE 1 MULTIPLE ENDOCRINE NEOPLASIA (MEN)

S3534 A Unique Presentation of Gastrinoma Complicated by Duodenal Perforation

Introduction: Neuroendocrine tumors are uncommon neoplasms with multiple different characteristics. They can be benign but also proliferate into malignant tumors with different pathological scenarios such as intestinal obstruction/ intraluminal mass. Gastrinomas are type of NET originating from pancreatic islet cells but can also arise from gastrin-producing cells in the duodenum. We present a case of gastrinoma, in which clinical period was complicated by small bowel perforation. Case Description/Methods: A 55-year-old lady with no significant past medical presented with complaints of abdominal pain, diarrhea and nausea/vomiting that was uncontrolled with symptomatic management. The patient underwent an EGD that showed esophagitis, gastritis, and duodenitis, and she was transferred to our facility for further work-up. She underwent a workup for Zollinger Ellison Syndrome in view of persistent symptoms. Her gastrin level came back elevated at 4,180 pg/ml after her medications were stopped to get the correct lab readings. A nuclear scan was scheduled for the patient to localize the gastrinoma lesion, but suddenly the patient became altered, hypotensive, and developed an acute abdomen. On further investigation with CT scan of the abdomen, patient was found to have pneumoperitoneum, secondary to bowel perforation. She underwent an emergent exploratory laparotomy, was found to have large perforations of the 3rd, 4th portion of the duodenum and several small perforations throughout the small bowel. A Para duodenal lymph node was taken and sent for pathology. Pathology revealed a well-differentiated neuroendocrine tumor: histological subtype gastrinoma. The patient underwent duodenal resection, gastrojejunostomy, cholecystectomy and feeding tube placement. Post-op period was complicated by patient having persistent dysphagia, initially to solids and progressed to have dysphagia to liquids as well. The patient underwent an EGD again which showed presence of esophageal stricture and had to undergo dilatation 6 times in a span of 2 months for symptom relief. She follows up with oncology and gastroenterology regularly and is scheduled to get a PET scan soon to rule out metastasis. (Figure) Discussion: Gastrinomas manifest with peptic ulcer disease symptoms but some patients present with diarrhea. Serum gastrin levels of > 1000 pg/ml with symptoms is diagnostic of gastrinoma. A secretin provocative test is used for diagnosis if gastrin levels are < 1000 pg/ml. As clinicians, we must be aware of the complications of gastrinoma.Figure 1.: Histopathological slides.

Hypoglycaemia due to Autoimmunity

Hirata disease is an insulin autoimmune disease characterized by non-exogenous hyper insulinemic postprandial hypoglycemia due to elevated insulin autoimmune antibodies (IAS), with no exogenous insulin and no pathological abnormalities of pancreatic islets cells, the diagnosis is often missed due to the rarity of the disease, failure to diagnose Hirata disease in a timely manner often results in exposing the patients to unnecessary investigation and surgical procedures.

Free fatty acid receptors in the endocrine regulation of glucose metabolism: Insight from gastrointestinal-pancreatic-adipose interactions.

Glucose metabolism is primarily controlled by pancreatic hormones, with the coordinated assistance of the hormones from gastrointestine and adipose tissue. Studies have unfolded a sophisticated hormonal gastrointestinal-pancreatic-adipose interaction network, which essentially maintains glucose homeostasis in response to the changes in substrates and nutrients. Free fatty acids (FFAs) are the important substrates that are involved in glucose metabolism. FFAs are able to activate the G-protein coupled membrane receptors including GPR40, GPR120, GPR41 and GPR43, which are specifically expressed in pancreatic islet cells, enteroendocrine cells as well as adipocytes. The activation of FFA receptors regulates the secretion of hormones from pancreas, gastrointestine and adipose tissue to influence glucose metabolism. This review presents the effects of the FFA receptors on glucose metabolism via the hormonal gastrointestinal-pancreatic-adipose interactions and the underlying intracellular mechanisms. Furthermore, the development of therapeutic drugs targeting FFA receptors for the treatment of abnormal glucose metabolism such as type 2 diabetes mellitus is summarized.

In vivo induction of regulatory T cells by anti-CD45RB antibody causes transferable tolerance to discordant human xenogenic islets.

The treatment of diabetes by islet cell transplantation has become an accepted therapy, with transplantation of xenogeneic islet cells an attractive alternative to the problem. Previous studies in mice have demonstrated that anti-CD45RB induce immune tolerance in human pancreatic islet cells. The current study was to define the mechanism of action of anti-CD45RB induced nonspecific immune tolerance to heteroantigens. A total of 1500 IEQ human islets were transplanted to diabetic B6μMT-/- mice, B6 mice, and μMT-/- diabetic mice undergoing thymectomy. These mice were treated short-term with doses of anti-CD45RB. CD4+Foxp3+Tregs were detected in the blood, peripheral lymphatic organs by flow cytometry, and immunohistochemistry. In addition, anti-CD25 mAb was administered to tolerant human islet cells B6μMT-/-mice. Mice then were transplanted with other human islet cells and received CD4+CD25+Tregs isolated from tolerant human islets mice to observe islet destruction. Anti-CD45RB treatment-induced tolerance to islets in both immunocompetent and B-cell-deficient mice (μMT-/- mice) by processes that were dependent on CD25+ Tregs, but not B cells. Anti-CD45RB treatment increased the number of CD4+Foxp3+Tregs cells. Anti-CD45RB treatment-induced immune tolerance that was antigen nonspecific, with Tregs playing an important role. Anti-CD45RB treatment-induced tolerance generated Tregs that could be transferred to another individual to manifest nonspecific immune tolerance. The results of the experiment suggest that anti-CD45RB induced tolerance to human islet xenografts is mediated by the proliferation of Tregs. These tolerogenic Tregs can be transferred to other mice and induce nonspecific immune tolerance.

Effects of Artificial Light at Night on Body Mass Index and Islet Autoimmunity Development in Children in Bavaria, Germany

Background and Aim: Worldwide, incidence of childhood obesity and early-onset type 1 diabetes (T1D) has risen over the past decades. Epidemiological studies have shown that in addition to genetic predisposition, environmental factors such as air pollution and temperature are associated with body mass index (BMI), T1D and its presymptomatic stage of autoimmunity to pancreatic islet cells. This study aimed to investigate the effect of exposure to light at night (LAN) on standardized BMI and islet autoimmunity (having 2 or more islet autoantibodies) in children in Bavaria, Germany. Methods: Exposure to LAN at baseline was assigned to the residential addresses of 52,636 children (&amp;#x3c;6 years of age) participating in the Fr1da study from 2015 to 2019. Information on demographic characteristics was extracted from self-administered questionnaires. We investigated the association of LAN with standardized BMI using linear regression and with islet autoimmunity using generalized additive models, segmented regression and quartile analysis. All models were adjusted for sex, age, family history of diabetes and area-level socioeconomic status (SES). Results: The mean standardized BMI was 0.12 &amp;#xb1; 1.04 and 225 children showed islet autoimmunity. A 10 nW/cm2/sr increase in LAN was significantly associated with a 2.14% increase in standardized BMI (95% confidence interval (CI): 0.86-3.45). Also, LAN exposure was linearly associated with a significantly higher odds of islet autoimmunity in children with exposure levels up to 11 nW/cm2/sr (Odds ratio (OR): 1.98; 95% CI: 1.14-3.45). Similar, quartile analyses showed a greater risk of islet autoimmunity especially for the third quartile (Q3: 5.2-11.6 nW/cm2/sr) of LAN compared to the lowest quartile (Q1: 0.0-2.0 nW/cm2/sr; OR: 1.71; 95% CI: 1.19-2.47). Conclusion: Exposure to LAN might be a further environmental risk factor contributing to higher BMI and islet autoimmunity in children. Keywords: Light at night, light pollution, body mass index, islet autoimmunity

Single-cell multi-omics analysis of human pancreatic islets reveals novel cellular states in type 1 diabetes

Brief Summary: This study used three high-throughput single-cell technologies to generate a pancreatic islet cell atlas from 24 organ donors with type 1 diabetes (T1D), autoantibody positive and healthy donors. The most remarkable finding was that a subset of exocrine ductal cells appears to acquire a signature of tolerogenic dendritic cells in an attempt at immune suppression in donors with T1D.

Maternal alloxan exposure induces damage in rat offspring lumbar vertebrae and protective role of arachidonic acid.

Vertebral abnormalities in offspring of diabetic mothers make major challenges worldwide and were not sufficiently studied before. To investigate the effects of alloxan-induced diabetes on rats' lumbar vertebrae, and to assess the potential beneficial impact of arachidonic acid. Pregnant rats were randomly equally divided into four groups: control, alloxan-induced diabetes received alloxan injection 150 mg∕kg, alloxan + arachidonic acid group received arachidonic acid 10 μg∕animal then given alloxan injection, and arachidonic acid group received it, until offspring age of three weeks. Six male offspring from each group were included in this study at ages of newborn, three-week-old, two-month-old, and their body measurements were recorded. Lumbar vertebrae and pancreas specimens were examined by light microscopy, morphometry, transmission electron microscopy (TEM), and immunohistochemistry for insulin expression. In alloxan-induced diabetes newborn, three-week-old, and two-month-old rats, body measurements were significantly declined, histomorphometry of 6th lumbar vertebrae revealed disorganized chondrocytes, with vacuolated cytoplasm, empty lacunae, diminished matrix staining, with areas devoid of cells. TEM showed shrunken reserve and proliferative cells, with irregular nuclei, and damaged mitochondria. In contrast, alloxan + arachidonic acid group had cytoarchitecture of lumbar vertebrae that were like control group. Histomorphometry of pancreas in alloxan-induced diabetes group showed significant reduction in pancreatic islets number and surface area, damaged pancreatic islet cells appeared atrophied with apoptotic nuclei, and very weak insulin immunostaining. Whereas alloxan + arachidonic acid group displayed healthy features of pancreatic islets, which resembled control group, with strong insulin immunostaining. Arachidonic acid mitigated alloxan-induced diabetes by its antidiabetic activity.

Bio-engineering of 3-D cell sheets for diabetic rats: Interaction between mesenchymal stem cells and beta cells in functional islet regeneration system

Type 1 diabetes is an autoimmune disease that emerges with the destruction of beta cells of pancreatic Langerhans islets. Three different therapeutical approaches have been developed so far; pancreas transplantation, islet transplantation, and cell-based therapies. Bioengineering cell sheets for tissue generating is one of the latest approaches that have been used to construct cell-sheets instead of single cells so that it mimics the in vivo environments more. In this study, extra-hepatic functional islet tissue was constructed by transferring the 3-D beta cells and GFP labelled MSCs MSC sheets to the subcutaneous site of rats with STZ-induced diabetes. rBM-MSCs and beta cells were cultured on the 6-well PIPAAm culture dishes. Obtained rBM-MSCs as two-cell sheets and beta cells cultured in droplets with matrigel has transplanted into the dorsal subcutaneous area of diabetic rats. Fasting blood glucose levels and body weights were evaluated for 30 days after transplantation. Immunocytochemistry analysis for the anti-apoptotic, anti-inflammatory, and angiogenetic effects of MSCs on the 30th day of subcutaneous cell transplantation. All recipient rats transplanted with beta-cells with MSCs returned toward normoglycemia by day 5 and remained at this level for 30 days. Immunocytochemical analyses supported that the MSCs and beta cells preserved their viability and function. MSCs secrete cytokines and growth factors TGF-β and IL-6; MSCs of the important features of the anti-apoptotic and anti-inflammatory properties, thanks to apoptosis of beta cells preserve graft explained by inhibition. In transplantation of MSCs induced angiogenesis and neovascularization, PECAM-1 and GFP positive simultaneously determining endothelial cells was observed indicating. Subcutaneous 3D beta-cell transplantation would be possible with the MSC-sheets as a feeder layer of beta cells. The beta-cell line is glucose-sensitive and has a high insulin release potential, and can be used as an alternative to islets in in vivo transplant studies.

SORLA mediates endocytic uptake of proIAPP and protects against islet amyloid deposition

ObjectiveSorting-related receptor with type A repeats (SORLA) is a neuronal sorting receptor that prevents accumulation of amyloid-beta peptides, the main constituent of senile plaques in Alzheimer disease. Recent transcriptomic studies show that SORLA transcripts are also found in beta cells of pancreatic islets, yet the role of SORLA in islets is unknown. Based on its protective role in reducing the amyloid burden in the brain, we hypothesized that SORLA has a similar function in the pancreas via regulation of amyloid formation from islet amyloid polypeptide (IAPP). MethodsWe generated human IAPP transgenic mice lacking SORLA (hIAPP:SORLA KO) to assess the consequences of receptor deficiency for islet histopathology and function in vivo. Using both primary islet cells and cell lines, we further investigated the molecular mechanisms whereby SORLA controls the cellular metabolism and accumulation of IAPP. ResultsLoss of SORLA activity in hIAPP:SORLA KO resulted in a significant increase in islet amyloid deposits and associated islet cell death compared to hIAPP:SORLA WT animals. Aggravated islet amyloid deposition was observed in mice fed a normal chow diet, not requiring high-fat diet feeding typically needed to induce islet amyloidosis in mouse models. In vitro studies showed that SORLA binds to and mediates the endocytic uptake of proIAPP, but not mature IAPP, delivering the propeptide to an endolysosomal fate. ConclusionsSORLA functions as a proIAPP-specific clearance receptor, protecting against islet amyloid deposition and associated cell death caused by IAPP.

Functional Insulinomas in a Rhesus Macaque (Macaca mulatta)

We report a rare case of functional insulinomas in a 16.7-year-old female Rhesus macaque (Macaca mulatta) that was presented with neuroglycopenic signs to the breeding colony hospital at the Tulane National Primate Research Center. At initial and follow-up examinations, the animal was consistently hypoglycaemic and was clinically maintained with additional fruits, other high-sugar food items and dextrose supplementation. Occasional episodes of seizure and collapse resolved quickly on administration of high-sugar food items. At necropsy, the uncinate process of the pancreas had a 2.2cm diameter, red, round, firm neoplastic mass, and another neoplasm was identified on histological examination of the head of pancreas. Histologically, neoplastic cells exhibited neuroendocrine packeting, resembled pancreatic islet cells and immunolabelled for chromogranin A, synaptophysin and insulin but not for somatostatin, gastrin or pancreatic polypeptide. A few cells immunolabelled for glucagon. The clinical signs and gross and histological findings were consistent with functional insulinomas.

Recidiverende hypoglykemie bij een patiënt zonder diabetes mellitus: een casusbespreking

Recurrent hypoglycemia in a patient without diabetes mellitus: a case report Hypoglycemia is an uncommon clinical problem in patients not being treated for diabetes mellitus. The presence of a hypoglycemic disorder in a person without diabetes mellitus should only be suspected in those patients in whom Whipple’s triad is documented. In this case report, the diagnostic exploration of a 79-year-old nondiabetic woman who presented with recurrent deep hypoglycemia, is described. The diagnosis of an insulinoma was established based on extensive laboratory testing (glucose, insulin, C-peptide, beta-hydroxybutyrate, proinsulin and sulfonylurea/meglitinide screening), a provocative fasting test and finally by localizing the tumor by means of magnetic resonance imaging. An insulinoma is a rare pancreatic islet cell tumor which may cause endogenous hyperinsulinism with frequent life-treating hypoglycemia, for which surgical enucleation is considered to be the therapy of choice. This case highlights the challenges endocrinologists face in the differential diagnosis of endogenous hyperinsulinism.

Immunological balance between Treg and Th17 lymphocytes as a key element of type 1 diabetes progression in children.

Type 1 diabetes (T1D) is autoimmune destruction of the beta cells of pancreatic islets. Due to complexity of that disease, the mechanisms leading to the tolerance breakdown are still not fully understood. Previous hypothesis of imbalance in the Th1 and Th2 cells as the main contributing factor has been recently changed towards role of other lymphocytes – regulatory (Treg) and IL-17A-producing (Th17). Our study aims to assess changes within Treg and Th17 cells in newly diagnosed T1D pediatric patients and their association with disease remission. Flow cytometry implementation allowed for Treg and Th17 analysis in studied groups and further combination with clinical and laboratory data. In addition, expression of diabetes-related genes was tested and evaluated in context of their association with studied lymphocytes. Initial results revealed that Treg and ratio Treg/Th17 are significantly higher in T1D than in healthy controls. Moreover, patients with lower HbA1c and daily insulin requirements demonstrated higher levels of Tregs. Similar tendency for insulin intake was also observed in reference to Th17 cells, together with high levels of these cells in patients demonstrating higher values for c-peptide after 2 years. In low-level Treg patients, that subset correlates with the c-peptide in the admission stage. In addition, higher levels of IL-10 were associated with its correlation with HbA1c and insulin dosage. In the context of gene expression, moderate associations were demonstrated in T1D subjects inter alia between CTLA4 and Treg or ratio Treg/Th17. Cumulatively, our data indicate a possible novel role of Treg and Th17 in mechanism of type 1 diabetes. Moreover, potential prognostic value of these populations has been shown in reference to diabetes remission.

Loss of FOXA2 induces ER stress and hepatic steatosis and alters developmental gene expression in human iPSC-derived hepatocytes

FOXA2 has been known to play important roles in liver functions in rodents. However, its role in human hepatocytes is not fully understood. Recently, we generated FOXA2 mutant induced pluripotent stem cell (FOXA2−/−iPSC) lines and illustrated that loss of FOXA2 results in developmental defects in pancreatic islet cells. Here, we used FOXA2−/−iPSC lines to understand the role of FOXA2 on the development and function of human hepatocytes. Lack of FOXA2 resulted in significant alterations in the expression of key developmental and functional genes in hepatic progenitors (HP) and mature hepatocytes (MH) as well as an increase in the expression of ER stress markers. Functional assays demonstrated an increase in lipid accumulation, bile acid synthesis and glycerol production, while a decrease in glucose uptake, glycogen storage, and Albumin secretion. RNA-sequencing analysis further validated the findings by showing a significant increase in genes associated with lipid metabolism, bile acid secretion, and suggested the activation of hepatic stellate cells and hepatic fibrosis in MH lacking FOXA2. Overexpression of FOXA2 reversed the defective phenotypes and improved hepatocyte functionality in iPSC-derived hepatic cells lacking FOXA2. These results highlight a potential role of FOXA2 in regulating human hepatic development and function and provide a human hepatocyte model, which can be used to identify novel therapeutic targets for FOXA2-associated liver disorders.

The Role of Statins (HMG-CoA Reductase Inhibitors) on Insulin Secretion from the Islets of Langerhans: A Systematic Review

Context: Statins are administered to decrease atherosclerosis in patients with coronary heart disease. These drugs enhance the risk of diabetes by affecting islets insulin secretion. Objectives: Therefore, this systematic review investigates the effect of statins on insulin secretion of islets of Langerhans in the related original studies. Methods: A preliminary search was performed in the PubMed, Scopus, Web of Science, and ProQuest databases. The search strategy terms were statin (hydroxymethylglutaryl-CoA reductase inhibitors), insulin secretion, and islets of Langerhans. The search elements were evaluated using the Mesh term system. Limits were used to include only review articles and no limits were set on language. The quality of the method and risk of bias was assessed by its tool. Results: After removing irrelevant articles to the subject, 20 articles fulfilled the inclusion criteria. In vivo studies revealed that pravastatin and rosuvastatin increase and decrease islets insulin secretion, while atorvastatin and fluvastatin reduced this variable, and pitavastatin had no effect. The results of in vitro studies showed that pravastatin and induced both increasing and decreasing effects on insulin secretion from the pancreatic islet cells. Also, administration of atorvastatin, rosuvastatin, fluvastatin, pitavastatin, simvastatin, and lovastatin decreased islet insulin secretion in the medium. Conclusions: Pravastatin could enhance pancreatic islet insulin secretion while other statins reduced this variable. Finally, the contradictory effect of statins on islets’ insulin secretion can indicate the existence of laboratory and clinical research in this regard.

Loss of Nexmif results in the expression of phenotypic variability and loss of genomic integrity

We identified two NEXMIF variants in two unrelated individuals with non-autoimmune diabetes and autistic traits, and investigated the expression of Nexmif in mouse and human pancreas and its function in pancreatic beta cells in vitro and in vivo. In insulin-secreting INS-1E cells, Nexmif expression increased strongly in response to oxidative stress. CRISPR Cas9-generated Nexmif knockout mice exhibited a reduced number of proliferating beta cells in pancreatic islets. RNA sequencing of pancreatic islets showed that the downregulated genes in Nexmif mutant islets are involved in stress response and the deposition of epigenetic marks. They include H3f3b, encoding histone H3.3, which is associated with the regulation of beta-cell proliferation and maintains genomic integrity by silencing transposable elements, particularly LINE1 elements. LINE1 activity has been associated with autism and neurodevelopmental disorders in which patients share characteristics with NEXMIF patients, and can cause genomic instability and genetic variation through retrotransposition. Nexmif knockout mice exhibited various other phenotypes. Mortality and phenotypic abnormalities increased in each generation in both Nexmif mutant and non-mutant littermates. In Nexmif mutant mice, LINE1 element expression was upregulated in the pancreas, brain, and testis, possibly inducing genomic instability in Nexmif mutant mice and causing phenotypic variability in their progeny.

Live enteroviruses, but not other viruses, detected in human pancreas at the onset of type 1 diabetes in the DiViD study

Aims/hypothesisEnterovirus (EV) infection of pancreatic islet cells is one possible factor contributing to type 1 diabetes development. We have reported the presence of EV genome by PCR and of EV proteins by immunohistochemistry in pancreatic sections. Here we explore multiple human virus species in the Diabetes Virus Detection (DiViD) study cases using innovative methods, including virus passage in cell cultures.MethodsSix recent-onset type 1 diabetes patients (age 24–35) were included in the DiViD study. Minimal pancreatic tail resection was performed under sterile conditions. Eleven live cases (age 43–83) of pancreatic carcinoma without diabetes served as control cases. In the present study, we used EV detection methods that combine virus growth in cell culture, gene amplification and detection of virus-coded proteins by immunofluorescence. Pancreas homogenates in cell culture medium were incubated with EV-susceptible cell lines for 3 days. Two to three blind passages were performed. DNA and RNA were extracted from both pancreas tissue and cell cultures. Real-time PCR was used for detecting 20 different viral agents other than EVs (six herpesviruses, human polyomavirus [BK virus and JC virus], parvovirus B19, hepatitis B virus, hepatitis C virus, hepatitis A virus, mumps, rubella, influenza A/B, parainfluenza 1–4, respiratory syncytial virus, astrovirus, norovirus, rotavirus). EV genomes were detected by endpoint PCR using five primer pairs targeting the partially conserved 5′ untranslated region genome region of the A, B, C and D species. Amplicons were sequenced. The expression of EV capsid proteins was evaluated in cultured cells using a panel of EV antibodies.ResultsSamples from six of six individuals with type 1 diabetes (cases) and two of 11 individuals without diabetes (control cases) contained EV genomes (p<0.05). In contrast, genomes of 20 human viruses other than EVs could be detected only once in an individual with diabetes (Epstein–Barr virus) and once in an individual without diabetes (parvovirus B19). EV detection was confirmed by immunofluorescence of cultured cells incubated with pancreatic extracts: viral antigens were expressed in the cytoplasm of approximately 1% of cells. Notably, infection could be transmitted from EV-positive cell cultures to uninfected cell cultures using supernatants filtered through 100 nm membranes, indicating that infectious agents of less than 100 nm were present in pancreases. Due to the slow progression of infection in EV-carrying cell cultures, cytopathic effects were not observed by standard microscopy but were recognised by measuring cell viability. Sequences of 5′ untranslated region amplicons were compatible with EVs of the B, A and C species. Compared with control cell cultures exposed to EV-negative pancreatic extracts, EV-carrying cell cultures produced significantly higher levels of IL-6, IL-8 and monocyte chemoattractant protein-1 (MCP1).Conclusions/interpretationSensitive assays confirm that the pancreases of all DiViD cases contain EVs but no other viruses. Analogous EV strains have been found in pancreases of two of 11 individuals without diabetes. The detected EV strains can be passaged in series from one cell culture to another in the form of poorly replicating live viruses encoding antigenic proteins recognised by multiple EV-specific antibodies. Thus, the early phase of type 1 diabetes is associated with a low-grade infection by EVs, but not by other viral agents. Graphical abstract

Jiedutongluotiaogan formula restores pancreatic function by suppressing excessive autophagy and endoplasmic reticulum stress

Context Jiedutongluotiaogan formula (JTTF), a traditional Chinese medicine (TCM), could promote islet function. However, the potential effect of JTTF on endoplasmic reticulum stress (ERS) and autophagy have not been reported. Objective This study explores the potential effect of JTTF on ERS and autophagy in the pancreas. Materials and methods The Zucker diabetic fatty (ZDF) rats were randomised into five groups, control, model, JTTF (1, 3, 5 g/kg/day for 12 weeks). LPS induced pancreatic β-cells were treated with JTTF (50, 100, 200 μg/mL). LPS was used to induce pancreatic β-cell injury, with cell viability and insulin secretion evaluated using MTT, glucose-stimulated insulin secretion (GSIS) assays, and PCR. Intracellular Ca2+ concentration was measured using flow cytometry, while ERS and autophagy levels were monitored via Western blotting and/or immunostaining. Results Compared with the model group, body weight, FGB, HbA1c, IPGTT, FINs, and HOMA-IR in JTTF treatment groups were significantly reduced. In islets cells treated with JTTF, the pancreatic islet cells in the JTTF group were increased, lipid droplets were reduced, and there was a decrease in Ca2+ (16.67%). After JTTF intervention, PERK, p-PERK, IRE1α, p- IRE1α, ATF6, eIF2α, GRP78, p-ULK1, LC3 and p62 expression decreased, whereas Beclin1and p-mTOR expression increased. In addition, the expression of proteins related to apoptosis in the JTTF groups were lower than those in the control group. Discussion and conclusions JTTF may alleviate pancreatic β-cell injury by inhibiting ER stress and excessive autophagy in diabetic rats. This provides a new direction for treating diabetes and restoring pancreatic dysfunction by TCM.

Going viral in the islet: mediators of SARS-CoV-2 entry beyond ACE2.

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Following initial infection of airway epithelia, SARS-CoV-2 invades a wide range of cells in multiple organs, including pancreatic islet cells. Diabetes is now recognised as a risk factor for severe COVID-19 outcomes, including hospitalisation and death. Additionally, COVID-19 is associated with a higher risk of new-onset diabetes and metabolic complications of diabetes. One mechanism by which these deleterious outcomes may occur is via the destruction of insulin-producing islet β cells, either directly by SARS-CoV-2 entry into β cells or indirectly due to inflammation and fibrosis in the surrounding microenvironment. While the canonical pathway of viral entry via angiotensin-converting enzyme 2 (ACE2) has been established as a major route of SARS-CoV-2 infection in the lung, it may not be solely responsible for viral entry into the endocrine pancreas. This is likely due to the divergent expression of viral entry factors among different tissues. For example, expression of ACE2 has not been unequivocally demonstrated in β cells. Thus, it is important to understand how other proteins known to be highly expressed in pancreatic endocrine cells may be involved in SARS-CoV-2 entry, with the view that these could be targeted to prevent the demise of the β cell in COVID-19. To that end, this review discusses alternate receptors of SARS-CoV-2 (CD147 and GRP78), as well as mediators (furin, TMPRSS2, cathepsin L, ADAM17, neuropilin-1, and heparan sulphate) that may facilitate SARS-CoV-2 entry into pancreatic islets independent of or in conjunction with ACE2.