| 1. |
- Granlund, Louise, et al.
(författare)
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Altered microvasculature in pancreatic islets from subjects with type 1 diabetes
- 2022
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 17:10
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Granlund, Louise, et al.
(författare)
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Histological and transcriptional characterization of the pancreatic acinar tissue in type 1 diabetes
- 2021
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Ingår i: BMJ Open Diabetes Research and Care. - : BMJ. - 2052-4897. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Despite a reduced function and volume of the exocrine pancreas in type 1 diabetes, the acinar cells remain understudied in type 1 diabetes research. The hypothesis of this study is that the acinar tissue is altered in subjects with type 1 diabetes compared with subjects without diabetes. Research design and methods The cell density, expression of digestive enzymes, and transcriptome of acinar tissue at varying distances from islets were analyzed using histology, immunostaining, and AmpliSeq RNA sequencing of laser capture microdissected tissue. Pancreases examined were from organ donors with or without type 1 diabetes. Results We demonstrate preserved acinar nuclei density and find no support of acinar atrophy in type 1 diabetes. Staining for digestive enzymes (amylase, lipase, and trypsin) demonstrated an evenly distributed expression in the exocrine parenchyma; although occasional amylase-negative regions appeared in tissue that had been formalin-fixed and paraffin-embedded, this phenomenon was not evident in frozen tissue. Gene set enrichment analysis of whole transcriptome data identified transcriptional alterations in type 1 diabetes that were present in the acinar tissue independent of the distance from islets. Among these, the two most enriched gene sets were Myc Targets V2 and Estrogen Response Early. Conclusion Taken together, these new data emphasize the involvement of the entire pancreas in type 1 diabetes pathology. The alteration of the gene sets Myc Targets V2 and Estrogen Response Early is a possible link to the increased incidence of pancreatic cancer in type 1 diabetes. © 2021 Authors.
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| 3. |
- Helker, Christian S M, et al.
(författare)
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A whole organism small molecule screen identifies novel regulators of pancreatic endocrine development.
- 2019
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Ingår i: Development. - : The Company of Biologists. - 0950-1991 .- 1477-9129. ; 146:14
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Tidskriftsartikel (refereegranskat)abstract
- An early step in pancreas development is marked by the expression of the transcription factor Pdx1 within the pancreatic endoderm, where it is required for the specification of all endocrine cell types. Subsequently, Pdx1 expression becomes restricted to the β-cell lineage, where it plays a central role in β-cell function. This pivotal role of Pdx1 at various stages of pancreas development makes it an attractive target to enhance pancreatic β-cell differentiation and increase β-cell function. In this study, we used a newly generated zebrafish reporter to screen over 8000 small molecules for modulators of pdx1 expression. We found four hit compounds and validated their efficacy at different stages of pancreas development. Notably, valproic acid treatment increased pancreatic endoderm formation, while inhibition of TGFβ signaling led to α-cell to β-cell transdifferentiation. HC toxin, another HDAC inhibitor, enhances β-cell function in primary mouse and human islets. Thus, using a whole organism screening strategy, this study identified new pdx1 expression modulators that can be used to influence different steps in pancreas and β-cell development.
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| 4. |
- Jonsson, Alexander, et al.
(författare)
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Protein Kinase R Is Constitutively Expressed in the Human Pancreas
- 2019
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Ingår i: Journal of Histochemistry & Cytochemistry. - : SAGE Publications. - 0022-1554 .- 1551-5044. ; 67:2, s. 99-105
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Tidskriftsartikel (refereegranskat)abstract
- Viral infection of the insulin-producing cells in the pancreas has been proposed in the etiology of type 1 diabetes. Protein kinase R (PKR) is a cytoplasmic protein activated through phosphorylation in response to cellular stress and particularly viral infection. As PKR expression in pancreatic beta-cells has been interpreted as a viral footprint, this cross-sectional study aimed at characterizing the PKR expression in non-diabetic human pancreases. PKR expression was evaluated in pancreas tissue from 16 non-diabetic organ donors, using immunohistochemistry, qPCR, and western blot. Immunohistochemistry and western blot showed readily detectable PKR expression in the pancreatic parenchyma. The qPCR detected PKR mRNA in both endocrine and exocrine samples, with a slightly higher expression in the islets. In conclusion, PKR is constitutively expressed in both endocrine and exocrine parts of the pancreas and its expression should not be interpreted as a viral footprint in pancreatic beta cells.
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| 5. |
- Jonsson, Alexander, et al.
(författare)
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Transcriptional profiles of human islet and exocrine endothelial cells in subjects with or without impaired glucose metabolism
- 2020
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Ingår i: Scientific Reports. - BERLIN GERMANY : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- In experimental studies, pancreatic islet microvasculature is essential for islet endocrine function and mass, and islet vascular morphology is altered in diabetic subjects. Even so, almost no information is available concerning human islet microvascular endothelial cell (MVEC) physiology and gene expression. In this study, islets and exocrine pancreatic tissue were acquired from organ donors with normoglycemia or impaired glucose metabolism (IGM) immediately after islet isolation. Following single-cell dissociation, primary islet- and exocrine MVECs were obtained through fluorescence-activated cell sorting (FACS) and transcriptional profiles were generated using AmpliSeq. Multiple gene sets involved in general vascular development and extracellular matrix remodeling were enriched in islet MVEC. In exocrine MVEC samples, multiple enriched gene sets that relate to biosynthesis and biomolecule catabolism were found. No statistically significant enrichment was found in gene sets related to autophagy or endoplasmic reticulum (ER) stress. Although ample differences were found between islet- and exocrine tissue endothelial cells, no differences could be observed between normoglycemic donors and donors with IGM at gene or gene set level. Our data is consistent with active angiogenesis and vascular remodeling in human islets and support the notion of ongoing endocrine pancreas tissue repair and regeneration even in the adult human.
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| 6. |
- Korsgren, Olle, et al.
(författare)
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Imagining a better future for all people with type 1 diabetes mellitus
- 2019
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Ingår i: Nature Reviews Endocrinology. - : Springer Science and Business Media LLC. - 1759-5029 .- 1759-5037. ; 15:11, s. 623-624
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- For a person with type 1 diabetes mellitus, lifelong insulin treatment is the only therapeutic option. However, increased blood levels of glucose are just a symptom of impaired beta-cell function. Approaching the centenary of the first insulin injection, broadening of international therapeutic guidelines to improve diagnostics, as well as monitor and preserve beta-cell function, is warranted.
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| 7. |
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| 8. |
- Kuric, Enida, et al.
(författare)
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No Evidence for Presence of Mucosal-Associated Invariant T Cells in the Insulitic Lesions in Patients Recently Diagnosed with Type 1 Diabetes
- 2018
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Ingår i: American Journal of Pathology. - : Elsevier BV. - 0002-9440 .- 1525-2191. ; 188:8, s. 1744-1748
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Tidskriftsartikel (refereegranskat)abstract
- Mucosal-associated invariant T (MAIT) cells are innate T cells that recognize bacteria-infected cells and are thought to play a role in autoimmune diseases. Translocation of duodenal bacteria and viruses to the pancreas through the pancreatic duct has been hypothesized to initiate an innate inflammatory response that could contribute to the development of type 1 diabetes, a process that could involve MAIT cells. In this study, we used immunohistochemistry and quantitative PCR to search for evidence of MAIT cells in the insulitic lesions in the pancreas of human patients recently diagnosed with type 1 diabetes. Only a few scattered MAIT cells were found within the exocrine parenchyma in all pancreatic samples, but no MAIT cells were found in association to the islets. Also, only low gene expression levels of the MAIT T-cell receptor V alpha 7.2-3 alpha 33 were found in the pancreas of patients with type 1 diabetes, in similar Levels as that in nondiabetic organ donors used as control. The absence of MAIT cells shown in insulitic lesions in humans questions the direct cytotoxic role of these cells in beta-cell destruction.
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| 9. |
- Neiman, Daniel, et al.
(författare)
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Multiplexing DNA methylation markers to detect circulating cell-free DNA derived from human pancreatic β cells
- 2020
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Ingår i: JCI Insight. - : American Society for Clinical Investigation. - 2379-3708. ; 5:14
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Tidskriftsartikel (refereegranskat)abstract
- It has been proposed that unmethylated insulin promoter fragments in plasma derive exclusively from β cells, reflect their recent demise, and can be used to assess β cell damage in type 1 diabetes. Herein we describe an ultrasensitive assay for detection of a β cell–specific DNA methylation signature, by simultaneous assessment of 6 DNA methylation markers, that identifies β cell DNA in mixtures containing as little as 0.03% β cell DNA (less than 1 β cell genome equivalent). Based on this assay, plasma from nondiabetic individuals (N = 218, aged 4–78 years) contained on average only 1 β cell genome equivalent/mL. As expected, cell-free DNA (cfDNA) from β cells was significantly elevated in islet transplant recipients shortly after transplantation. We also detected β cell cfDNA in a patient with KATP congenital hyperinsulinism, in which substantial β cell turnover is thought to occur. Strikingly, in contrast to previous reports, we observed no elevation of β cell–derived cfDNA in autoantibody-positive subjects at risk for type 1 diabetes (N = 32), individuals with recent-onset type 1 diabetes (<4 months, N = 92), or those with long-standing disease (>4 months, N = 38). We discuss the utility of sensitive β cell cfDNA analysis and potential explanations for the lack of a β cell cfDNA signal in type 1 diabetes.
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| 10. |
- Oikarinen, Sami, et al.
(författare)
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Characterisation of enterovirus RNA detected in the pancreas and other specimens of live patients with newly diagnosed type 1 diabetes in the DiViD study
- 2021
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Ingår i: Diabetologia. - : Springer Nature. - 0012-186X .- 1432-0428. ; 64:11, s. 2491-2501
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis The Diabetes Virus Detection (DiViD) study is the first study to laparoscopically collect pancreatic tissue and purified pancreatic islets together with duodenal mucosa, serum, peripheral blood mononuclear cells (PBMCs) and stools from six live adult patients (age 24-35 years) with newly diagnosed type 1 diabetes. The presence of enterovirus (EV) in the pancreatic islets of these patients has previously been reported. Methods In the present study we used reverse transcription quantitative real-time PCR (RT-qPCR) and sequencing to characterise EV genomes present in different tissues to understand the nature of infection in these individuals. Results All six patients were found to be EV-positive by RT-qPCR in at least one of the tested sample types. Four patients were EV-positive in purified islet culture medium, three in PBMCs, one in duodenal biopsy and two in stool, while serum was EVnegative in all individuals. Sequencing the 5' untranslated region of these EVs suggested that all but one belonged to enterovirus B species. One patient was EV-positive in all these sample types except for serum. Sequence analysis revealed that the virus strain present in the isolated islets of this patient was different from the strain found in other sample types. None of the islet-resident viruses could be isolated using EV-permissive cell lines. Conclusions/interpretation EV RNA can be frequently detected in various tissues of patients with type 1 diabetes. At least in some patients, the EV strain in the pancreatic islets may represent a slowly replicating persisting virus.
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