TY - JOUR. T1 - A comparative study of amino acid consumption by rat islet cells and the clonal beta-cell line BRIN-BD11 - the functional significance of L-alanine. AU - Dixon, G. AU - Nolan, J. AU - McClenaghan, Neville. AU - Flatt, Peter. AU - Newsholme, P. PY - 2003/12. Y1 - 2003/12. N2 - Evidence has been published that L-alanine may, under appropriate conditions, promote insulin secretion in normal rodent islets and various beta cell lines. Previous results utilising the clonal beta-cell line BRIN-BD11, demonstrated that alanine dramatically elevated insulin release by a mechanism requiring oxidative metabolism. We demonstrate in this paper that addition Of L-alanine had an insulinotropic effect in dispersed primary islet cells. Addition Of D-glucose increased L-alanine consumption in both BRIN-BD11 cells and primary islet cells. L-glutamine consumption in the BRIN-BD11 cell line and primary rat islets was also determined. The consumption rate was in line with that previously reported for ...

The proliferative response of non-β islet endocrine cells in response to type 1 diabetes (T1D) remains undefined. We quantified islet endocrine cell proliferation in a large collection of non-diabetic control and T1D human pancreata across a wide range of ages. Surprisingly, islet endocrine cells with abundant proliferation were present in many adolescent and young adult T1D pancreata. But, the proliferative islet endocrine cells were also present in similar abundance within control samples. We queried the proliferating islet cells with antisera against various islet hormones. Although PP, somatostatin, and ghrelin cells did not exhibit frequent proliferation, glucagon-expressing α-cells were highly proliferative in many adolescent and young adult samples. Notably, α-cells only comprised a fraction (∼1/3) of the proliferative islet cells within those samples; most proliferative cells did not express islet hormones. The proliferative hormone negative cells uniformly contained ...

The proliferative response of non-β islet endocrine cells in response to type 1 diabetes (T1D) remains undefined. We quantified islet endocrine cell proliferation in a large collection of non-diabetic control and T1D human pancreata across a wide range of ages. Surprisingly, islet endocrine cells with abundant proliferation were present in many adolescent and young adult T1D pancreata. But, the proliferative islet endocrine cells were also present in similar abundance within control samples. We queried the proliferating islet cells with antisera against various islet hormones. Although PP, somatostatin, and ghrelin cells did not exhibit frequent proliferation, glucagon-expressing α-cells were highly proliferative in many adolescent and young adult samples. Notably, α-cells only comprised a fraction (∼1/3) of the proliferative islet cells within those samples; most proliferative cells did not express islet hormones. The proliferative hormone negative cells uniformly contained ...

The pancreatic islets are collections of endocrine cells, dispersed throughout the pancreas. In adult islets, endocrine cells are closely associated with capillary endothelial cells and receive a high blood perfusion. Transplanted pancreatic islets, on the other hand, have a vascular disturbance, manifested as decreased blood vessel density. Besides impaired islet blood perfusion and oxygenation, this means that the normal close proximity between endothelial cells and β-cell in adult islets is interrupted. The aim of the thesis was to investigate if, and to what extent, β-cells and islet endothelial cells can interact with one another. This hypothesis was investigated during physiological growth of pancreatic islets, following transplantation and in vitro. We observed that islet endothelial and endocrine cell replication coincided immediately after birth, as well as during pregnancy. In pregnant animals, β-cell proliferation colocalized to islets with increased endothelial cell replication, ...

The long-term in vitro culture and differentiation of human pancreatic islets is still hindered by the inability to emulate a suitable microenvironment mimicking physiological extracellular matrix (ECM) support and nutrient/oxygen perfusion. This is further amplified by the current lack of a non-invasive and rapid monitoring system to readily evaluate cellular processes. In this study, we realized a viable method for non-invasively monitoring isolated human pancreatic islets in vitro. Islets are induced to dedifferentiate into proliferative duct-like structures (DLS) in preparation for potential and subsequent re-differentiation into functional islet-like structures (ILS) in a process reminiscent of islet regeneration strategies. This long-term in vitro process is conducted within a three-dimensional microenvironment involving islets embedded in an optimized ECM gel supported by microfabricated three-dimensional scaffolds. The islet-scaffold is then housed and continuously perfused within ...

The fluorescent probe SBFI was used to monitor the influence of acetylcholine (ACh) on the cytosolic concentration of free Na+ (Na+i) in single mouse pancreatic B-cells. In the presence of 3 mM glucose and 135 mM extracellular Na+, Na+i averaged 16.6 mM. ACh (100 microM) increased Na+i by approximately 80%. This rise was prevented by atropine, a blocker of muscarinic receptors, and by omission of extracellular Na+, but still occurred if the sodium pump was blocked by ouabain. It was unaffected by tetrodotoxin, a blocker of voltage-sensitive Na+ channels, and was not mimicked by depolarization of the cells with high K+. It is concluded that activation of muscarinic receptors increases the membrane permeability to Na+ in pancreatic B-cells. ...

In the present study, we demonstrated the protein expression of three PDK isoforms (PDK1, PDK2, and PDK4) in rat pancreatic islets (no sufficiently specific antibodies are as yet available for PDK3). We also showed, for the first time, that the PDK isoform protein expression profile of rat pancreatic islets is selectively modified in response to prolonged starvation. A major novel finding is that PDK1 and (to a lesser extent) PDK2 protein expression in the rat pancreatic islet is suppressed by prolonged starvation, whereas the protein expression of the third PDK isoform, PDK4, is specifically upregulated by starvation. We also demonstrated, for the first time, specific upregulation of PDK4 and PPAR-α protein expression in rat pancreatic islets in response to the administration of the PPAR-α agonist WY14,643, identifying a potential role for PPAR-α-linked functions in the islet response to starvation. We analyzed the impact of antecedent changes in islet PDK protein expression and PPAR-α ...

The pancreatic islet of Langerhans is composed of endocrine cells producing and releasing hormones from secretory granules in response to various stimuli for maintenance of blood glucose homeostasis. In order to adapt to a variation in functional demands, these islets are capable of modulating their hormone secretion by increasing the number of endocrine cells as well as the functional response of individual cells. A failure in adaptive mechanisms will lead to inadequate blood glucose regulation and thereby to the development of diabetes. It is therefore necessary to develop tools for the assessment of both pancreatic islet mass and function, with the aim of understanding cellular regulatory mechanisms and factors guiding islet plasticity. Although most of the existing techniques rely on the use of artificial indicators, we present an imaging methodology based on intrinsic optical properties originating from mature insulin secretory granules within endocrine cells that reveals both pancreatic islet mass

Enhanced beta-cell function with normal islet gene expression following adaptation of b-cell mass to substrate oversupply. Am J Physiol Endoc Metab. 2001; 280:E788-E796 ...

Many GTP-binding proteins (GBPs) are modified by mevalonic acid (MVA)-dependent isoprenylation, carboxyl methylation or palmitoylation. The effects of inhibitors of these processes on insulin release were studied. Intact pancreatic islets were shown to synthesize and metabolize MVA and to prenylate several candidate proteins. Culture with lovastatin (to inhibit synthesis of endogenous MVA) caused the accumulation in the cytosol of low-M(r) GBPs (labelled by the [alpha-32P]GTP overlay technique), suggesting a disturbance of membrane association. Concomitantly, lovastatin pretreatment reduced glucose-induced insulin release by about 50%; co-provision of 100-200 microM MVA totally prevented this effect. Perillic acid, a purported inhibitor of the prenylation of small GBPs, also markedly reduced glucose-induced insulin secretion. Furthermore, both N-acetyl-S-trans, trans-farnesyl-L-cysteine (AFC), which inhibited the base-labile carboxyl methylation of GBPs in islets or in transformed beta-cells, ...

Effect of rapamycin on pancreatic islet morphology in NONcNZO10 mice.(A) Islet numbers and size variability do not differ between untreated and rapa-treated gro

Aims: To test whether the immersion of the pancreas in solutions of 1 or 2 mg/mL of collagenase in 4°C for 24 hours, for the isolation of Langerhans islets, rises the yield of islets/grams of pancreatic tissue. Methods: Experimental study with mouses, performed in the Laboratory of Nephrology of the Instituto de Pesquisas Biológicas do Hospital São Lucas da PUCRS, Porto Alegre, RS. After the animals have been sacrified under anesthesia, the pancreas were removed and divided in four groups, according the technique used for isolating the islets. A) collagenase 1mg/mL, in 4ºC for 24 hours and heating for 39ºC for 15 minutes. B) collagenase 2mg/mL with the same previous described steps. C) collagenase 1mg/mL and heating of the solution in the same day, in 39ºC for 15 minutes. D) collagenase 2mg/mL and heating of the solution in the same day, in 39ºC for 15 minutes. We verified the viability of the islet through the trypan blue test. Results: The median numbers of isolated islets in the groups ...

Supplementary MaterialsDisclaimer: Helping information continues to be peer\reviewed however, not copyedited. provides 1093 \, 1544 \ and 619 \cells. TJP-596-197-s003.avi (45M) GUID:?5035FCE3-4649-4C6A-A19D-1AF9D527863F Video S4. Simulation of high MAP2K2 blood sugar in individual islet model M4. Simulation of style of 4th islet structures in high blood sugar. This islet provides 970 \, 2256 \ and 351 \cells. TJP-596-197-s004.avi (42M) GUID:?B4E8FEA3-034E-4AB5-9D47-EADDEFA97262 Video S5. Simulation of high blood sugar in individual islet model M5. Simulation of style of 5th islet structures in high blood sugar. This islet provides 650 \, 1174 \ and 275 \cells. TJP-596-197-s005.7z (34M) GUID:?5F72EC67-2BF6-442A-80A7-64B37761CA61 Video S6. Simulation of high blood sugar in individual islet model M6. Simulation of style of 6th islet structures in high blood sugar. This islet provides 838 \, 1362 \ and 661 \cells. TJP-596-197-s006.7z (27M) GUID:?5BCAA42B-63D0-4607-9231-66E11334C30D Abstract Tips We ...

Inhibitory effects on glucose-induced insulin secretion by previous palmitate were additive to the inhibitory effects exerted by previous high glucose (11 and 27 mmol/l). Palmitate-induced inhibition of insulin secretion was evident after exposure to 25 μmol/l added fatty acid. The insulin content of islets exposed to fatty acids was significantly reduced, and glucose-induced proinsulin biosynthesis was inhibited by 59% after palmitate addition and by 51% after oleate exposure (P,0.01). These effects were partly prevented by etomoxir (P,0.05). The activity of PDH in mitochondrial extracts of islets preexposed for 48 h to palmitate was decreased by 35% (P,0.05) υs. that in control islets, whereas the activity of PDH kinase (which inactivates PDH) was significantly increased in the same preparations (P,0.05 ...

ADDITIONAL INFORMATION FOR POTENTIAL APPLICANTS TO THE HUMAN PANCREATIC ISLET CELL RESOURCE CENTER (ICR) COOPERATIVE AGREEMENT Release Date: February 5, 2001 NOTICE: NOT-RR-01-004 National Center for Research Resources (http://www.ncrr.nih.gov) National Institute of Diabetes and Digestive and Kidney Diseases (http://www.niddk.nih.gov) Juvenile Diabetes Research Foundation International (http://www.jdf.org) This notice is an addendum to RFA-RR-01-002, entitled HUMAN PANCREATIC ISLET CELL RESOURCE CENTER (ICR), which was previously published as Request for Applications RR-01-002 in the NIH Guide for Grants and Contracts (https://grants.nih.gov/grants/guide/rfa-files/RFA-RR-01-002.html). The listing of FDA guidance documents and information relevant to this RFA has been expanded to include: CELL/TISSUE BASED DOCUMENTS o Guidance for Industry: Guidance for Human Somatic Cell Therapy and Gene Therapy (1998) available at: http://www.fda.gov/cber/gdlns/somgene.pdf o Points to Consider in the ...

Type 1 diabetes mellitus (T1DM) is an autoimmune disease in which T-cells and macrophages invade the islets of Langerhans and selectively destroy the insulin producing β-cells, either directly or through the secretion of e.g. cytokines and nitric oxide (NO). This thesis has studied possible strategies to prevent T1DM. In β-cells and macrophages, NO is produced by inducible nitric oxide synthase (iNOS). In the first study, we found that 1400W, a highly selective inhibitor of iNOS could prevent interleukin (IL)-1β induced suppression of rat islet function in vitro, but not diabetes induced by multiple low dose streptozotocin (MLDS), a well established animal model for autoimmune diabetes, in vivo. Next, we wanted to test a new type of high affinity blocker of IL-1 action, called IL-1 trap, in vitro. Here we found that an IL-1 trap could prevent the suppressive effects by IL-1β on rat pancreatic islet function. Also, it was sufficient to block the action of IL-1β to prevent islet cell death ...

New study confirms hanging drop microfluidics platform for miniaturized islet perifusion assays enables high-resolution assessment of islet insulin secretion from single human islets over time. PDF Version. Schlieren and Basel, Switzerland - May 19, 2020 InSphero AG, the pioneer of 3D cell-based assay technology, and the Bio Engineering Laboratory at ETH Zürich today announced that a recent study published in Advanced Biosystems confirms that organ-on-a-chip solutions can be harnessed to advance diabetes drug discovery. Results of this research collaboration between InSphero and microfluidic system engineers at ETH Zürichs department of Biosystems Science and Engineering demonstrated that using 3D InSight™ Human Islet Microtissues in a novel microfluidic hanging-drop-based perifusion assay system enables the study of physiologically relevant dynamic insulin secretion with low sample-to-sample variation and at high temporal resolution.. Glucose-stimulated insulin release from pancreatic ...

The analysis of T-cell responses to islet proteins using the CI assay has allowed us to identify, in cross-sectional studies, cellular islet autoimmunity in T1D (21-23,25), in subjects at risk for T1D (24), and in phenotypic T2D patients (26-30). The presence of islet-specific cellular autoimmunity in T2D patients was also recently confirmed by an independent laboratory (35). However, longitudinal studies investigating islet autoimmune development in T2D patients have been lacking.. In this study, we observed development of islet autoimmunity, measured by islet Abs and islet-specific T-cell responses, in 61% of the phenotypic T2D patients. We also observed a significant association between positive islet-reactive T-cell responses and a more rapid decline in β-cell function as assessed by FCP and glucagon-SCP responses. Moreover, the high percentage (30%) of Ab−T+ T2D patients observed in this study supports our previously published cross-sectional observations and demonstrates the importance ...

In this study, we identified TGF-βi as a vital trophic factor for islet β-cells. It enhanced islet survival and function both in vitro and in vivo. Of greater interest, it seemed to be able to induce islet neogenesis, which resulted in insulin-positive cell clusters in young mice and giant islets in older mice.. TGF-βi can function as glue between the ECM and cells: it can attach to collagen in ECM through one or more of its four FAS1 domains and attach cells via integrins to its remaining FAS1 domain as well as its C-terminal RGD domain. In addition, TGF-βi can also function as glue between cells: it can hold different cells together with its four FAS1 domains and RGD domain, all of which can interact with various integrins on the cell surface. This is likely the mechanism by which recombinant and Tg TGF-βi conferred better islet integrity during culture.. β-cells in islets need trophic factors to survive and function, both in vivo and in vitro. Isolated islets gradually die in culture. ...

Foetal islets are functionally immature but retain their capacity for proliferation if harvested and cultured in an appropriate manner. Graft function was shown to depend largely on the gestational age and conditions of organ culture prior to transplantation. The required period of organ culture for optimal graft function was investigated for foetal mouse pancreas of different gestational ages. The growth of the graft in situ also depended on the diabetic state of the host, and chronic hyperglycaemia appeared to impair graft function. Subsequent studies using NOD recipient mice as a model for IDDM showed that recurrent autoimmune disease was seen in foetal islet isografts but rapid rejection of allografts and foetal pig xenografts also occurred. The striking differences seen between the allo-, and xenograft response was the presence of many eosinophils that dominated the infiltrate at the xenograft site. However, HAR was not a problem in this discordant xenograft and Gal(1-3)Gal expression, the ...

DESCRIPTION (provided by applicant): Transplantation of human islets has great potential as an effective means of treating insulin dependent diabetes mellitus. Primary non-function is the main cause of islet graft failure and it results in the need for multi-donor transplants. We will test the hypothesis that islet engraftment can he enhanced simultaneously by expressing growth factor gene like human Vascular Endothelial Growth Factor (hVEGF) that promotes islet revascularization, and antiapoptotic gene like human interleukin-1 receptor antagonist (hIL-IRa) to prevent apoptosis of transplanted islets in the host. In preliminary studies, higher levels of hVEGF were secreted from human islets transfected with bicistronic adenoviral vector encoding hVEGF and Green Fluorescent Protein (Acv-GFP-hVEGF), while hVEGF secretion from Adv-GFP transfected and mock-transfected islets was very low. Insulin release from transfected islets was comparable to mock-transfected islets. Proapoptotic cytokines ...

We present several pieces of experimental evidence that IGRP-specific effector-memory CD8+ T cells in the peripheral lymphoid tissue of NOD mice have emigrated from islets. First, the T cell number in the periphery correlated with the severity of islet pathology and was reduced in mutant strains of NOD mice with reduced islet pathology but normal pancreatic lymph node T cell priming. Second, transferred naive T cells acquired effector memory phenotype in the islets, after exit from the pancreatic lymph node, and the peripheral T cells displayed a phenotype similar to that acquired in islets. Finally, islet-infiltrating T cells emigrated from islets transplanted into syngeneic, but immunodeficient NOD mice, were found in the peripheral lymphoid organs and invaded the native pancreas and caused diabetes, indicating that this chain of events can occur. We suggest that this also can occur from native, untransplanted islets. In T1D, we suggest that islet pathology results in proliferation and ...

The endocrine pancreas is an organ of enormous importance, since its dysfunction causes diabetes, one of the most common human diseases in the world. Regulation of pancreatic endocrine cell determination and differentiation requires a unique set of transcription factors, including basic helix-loop-h …

Elevated total islet leucocyte content and proinflammatory mediators correlated with islet dysfunction, suggesting that heterogeneous insulitis occurs during the development of islet dysfunction in type 2 diabetes. In addition, the altered B cell content highlights a potential role for the adaptive …

In the pancreas of T1D patients, the immune system selectively destroys β cells in a process known as insulitis (12). Recently, immune cells have also been demonstrated to infiltrate the pancreata of T2D patients (10-14). In T1D, an autoimmune reaction characterizes the insulitis, whereas a more autoinflammatory infiltrate appears to characterize the insulitis associated with T2D (10-14). Moreover, islet-reactive T cells responding to multiple islet proteins have been found in both T1D patients (15-18) and phenotypic T2D patients with and without islet autoantibodies, the historical hallmark of islet autoimmunity (19-22). Potential differences between T1D patients and autoimmune phenotypic T2D patients in the islet proteins recognized by T cells have been identified, hinting at potentially different pathogenic mechanisms (21). These studies suggest that T-cell-mediated islet damage may be a component of more than just classic T1D. Recently, we demonstrated in phenotypic T2D patients that the ...

Enhanced expression of chemotactic cytokines (aka chemokines) within pancreatic islets likely contributes to islet inflammation by regulating the recruitment and activation of various leukocyte populations, including macrophages, neutrophils, and T-lymphocytes. Because of the powerful actions of these chemokines, precise transcriptional control is required. In this review, we highlight what is known about the signals and mechanisms that govern the transcription of genes encoding specific chemokine proteins in pancreatic islet β-cells, which include contributions from the NF-κB and STAT1 pathways. We further discuss increased chemokine expression in pancreatic islets during autoimmune-mediated and obesity-related development of diabetes.

article{8523110, abstract = {Endothelial-endocrine cell interactions and vascular endothelial growth factor (VEGF)-A signalling are deemed essential for maternal islet vascularisation, glucose control and beta cell expansion during mouse pregnancy. The aim of this study was to assess whether pregnancy-associated beta cell expansion was affected under conditions of islet hypovascularisation. Soluble fms-like tyrosine kinase 1 (sFLT1), a VEGF-A decoy receptor, was conditionally overexpressed in maternal mouse beta cells from 1.5 to 14.5 days post coitum. Islet vascularisation, glycaemic control, beta cell proliferation, individual beta cell size and total beta cell volume were assessed in both pregnant mice and non-pregnant littermates. Conditional overexpression of sFLT1 in beta cells resulted in islet hypovascularisation and glucose intolerance in both pregnant and non-pregnant mice. In contrast to non-pregnant littermates, glucose intolerance in pregnant mice was transient. sFLT1 overexpression ...

The beta cells are particularly important because they make insulin. Degeneration of the beta cells is the main cause of type I (insulin-dependent) diabetes mellitus.

Guanine nucleotide-binding proteins (G-proteins) are known to act as important modulators of insulin release from the islets of Langerhans. We have recently found that the deoxynojirimycin-derivative emiglitate, a recognized inhibitor of intestinal α-glucosidehydrolase activity, is a powerful inhibitor of glucose-induced insulin release. With the use of isolated mouse islets the present investigation was performed in a primary attempt to elucidate whether this inhibitory mechanism in some way was linked to the β-cell G-protein system. Treatment of freshly isolated islets with pertussis toxin (PTX), which is known to inactivate the Gi-proteins, abolished the inhibitory effect of the α2-adrenoceptor agonist clonidine on insulin release stimulated by the phosphodiesterase inhibitor IBMX in the presence of the protein kinase C activator TPA and even changed it into an increase. Emiglitate did not display any inhibitory action on insulin release induced by these secretagogues. Similarly, ...

Guanine nucleotide-binding proteins (G-proteins) are known to act as important modulators of insulin release from the islets of Langerhans. We have recently found that the deoxynojirimycin-derivative emiglitate, a recognized inhibitor of intestinal α-glucosidehydrolase activity, is a powerful inhibitor of glucose-induced insulin release. With the use of isolated mouse islets the present investigation was performed in a primary attempt to elucidate whether this inhibitory mechanism in some way was linked to the β-cell G-protein system. Treatment of freshly isolated islets with pertussis toxin (PTX), which is known to inactivate the Gi-proteins, abolished the inhibitory effect of the α2-adrenoceptor agonist clonidine on insulin release stimulated by the phosphodiesterase inhibitor IBMX in the presence of the protein kinase C activator TPA and even changed it into an increase. Emiglitate did not display any inhibitory action on insulin release induced by these secretagogues. Similarly, ...

Almost 80 years ago, Dr. Frederick Banting published a report about use of pancreatic Islets to treat diabetes. He obtained those Islets from the pancreas of a dog. By first tying-off that pancreas, he eliminated the digestive enzymes that would otherwise have destroyed the insulin in the Islets.

Fisher MM, Perez Chumbiauca CN, Mather KJ, Mirmira RG, Tersey SA. Detection of islet ß-cell death in vivo by multiplex PCR analysis of differentially methylated DNA. Endocrinology. 2013 Sep; 154(9):3476-81 ...

Spaeth JM, Liu JH, Peters D, Guo M, Osipovich AB, Mohammadi F, Roy N, Bhushan A. Magnuson MA, Hebrok M, Wright CVE, Stein R; Diabetes. 2019 Sep; 68(9):1806-1818. doi: 10.2337/db19-0349. In the September issue of Diabetes, Jason Spaeth and colleagues from Roland Steins lab at Vanderbilt present a series of elegant experiments that together dissect a complex molecular mechanism of transcription factor and coregulator recruitment. Using mouse models and a host of molecular assays, including RNA- and ChIP-seq, they illuminate the role of Pdx1:Swi/Snf complexes in pancreas organogenesis and β-cell maintenance. Their data suggest that transcriptional coregulator recruitment is crucial for the generation and activity of other islet cell types as well. These findings contribute to a broader understanding of the disease mechanism of type 2 diabetes in humans, in which a subset of β-cell quit making insulin, and pancreas volume is a major risk factor.. Genialis is thrilled to support the Stein labs ...

Mice with 50% Pdx1, a homeobox gene critical for pancreatic development, had worsening glucose tolerance with age and reduced insulin release in response to glucose, KCl, and arginine from the perfused pancreas. Surprisingly, insulin secretion in perifusion or static incubation experiments in response to glucose and other secretagogues was similar in islets isolated from Pdx1+/- mice compared with Pdx1+/+ littermate controls. Glucose sensing and islet Ca2+ responses were also normal. Depolarization-evoked exocytosis and Ca2+ currents in single Pdx1+/- cells were not different from controls, arguing against a ubiquitous β cell stimulus-secretion coupling defect. However, isolated Pdx1+/- islets and dispersed β cells were significantly more susceptible to apoptosis at basal glucose concentrations than Pdx1+/+ islets. BclXL and Bcl-2 expression were reduced in Pdx1+/- islets. In vivo, increased apoptosis was associated with abnormal islet architecture, positive TUNEL, active caspase-3, and ...

Within the pancreatic islet, the intra-islet vasculature plays a crucial role in pancreatic development, islet function and beta cell survival. We have shown that vascular endothelial cells are rapidly lost from isolated pancreatic islets during culture. Endothelial progenitor cells (EPCs) represent a potential cellular therapy that may replenish diminished intra-islet endothelial cell populations and improve the engraftment of transplanted pancreatic islets. In addition, EPCs may directly affect the function of pancreatic beta cells. In a diabetic murine syngeneic marginal mass islet transplant model we found that co-transplanted EPCs markedly improved the cure rate and initial glycaemic control of transplanted islets. Gene expression data indicate that EPCs, or their soluble products, modulate the expression of the beta cell surface molecule connexin 36, and affect glucose-stimulated insulin release. Using transwell co-cultures of MIN6 and MS-1 cell lines we have further examined the molecules ...

The various endocrine cell types present in mammalian Islets of Langerhans express a range of lipid-responsive G-proteln coupled receptors (GPCRs) including GPR119 and GPR120. These are each reported to be expressed In islet beta-cells and GPR 119 has been Implicated In the augmentation of glucose-stimulated insulin secretion by certain derivatives of long chain unsaturated fatty acids. By contrast GPR 120 does not appear to regulate insulin secretion and its role is unclear In addition to their ability to regulate hormone secretion long-chain fatty acids and their derivatives can also influence beta-cell viability but It IS unclear whether GPCRs are involved in mediating this response Therefore. the work undertaken in thesis has explored the possible involvement of GPR119 and GPR120 in the regulation of beta-cell viability. Long chain fatty acids exert differential effects on beta-cell viabilty according to their chain length and degree of unsaturation. Saturated molecules with chain lengths of ...

If doctors were able to place healthy, insulin-producing islets into a person with diabetes in a minimally invasive procedure that needs to be repeated only occasionally, diabetes care as we know it would be finished. Patients might occasionally need insulin, and would of course want to keep an eye on their blood glucose levels, but the often-grueling regimen many of us now follow would be a thing of the past.. What exactly is islet transplantation, anyway? In fact, what are islets?. What Are Islets?. Technically, theyre called the islets of Langerhans. These are clusters of cells that lie within the pancreas and produce insulin, glucagon and other hormones. When a person lacks beta cells, he or she also lacks a sufficient supply of these vital hormones, resulting in the condition we call diabetes.. Islets have been said to resemble fine golden sand, measuring about 1/4 millimeter in diameter, which makes them visible to the naked eye. Scientists can isolate islets from pancreatic tissue only ...

Scientists publishing in Nature have shown that is it possible to generate rat/mouse chimeric pancreatic tissue by injecting mouse stem cells into rat early embryos. The resulting tissue could be transplanted into diabetic mice, restoring normal control over blood glucose. These findings may have implication for the future treatment of diabetes in humans.. Dr Shareen Forbes, Reader in Diabetes and Endocrinology, University of Edinburgh, & Lead Physician for the Islet Transplantation Programme in Scotland, said:. Type 1 diabetes is caused by damage to specific insulin-secreting cells found in specialised structures in the pancreas called islets. Transplanting healthy islets is a proven therapy for people with type 1 diabetes but the lack of donor tissue is a major limiting factor for widespread use of this approach. This study involving rats and mice raises the possibility that we may one day be able to grow donor islets in animals of another species. The findings are exciting but there are ...

We used transplantation of human juvenile and adult islets into immunodeficient NSG mice (44, 45) to investigate mechanisms controlling human islet cell proliferation. Compared with retrospective studies of cadaveric pancreata or in vitro islet culture-based assays, this in vivo transplantation strategy afforded experimental flexibility, including relatively prolonged observation times, prospective exposure of islets to sequential or concurrent schedules of drugs, and serial measures of insulin secretion in response to Ex-4. In our transplantation model, the maintenance of greater levels of β cell proliferation after transplantation indicates that the proliferation resulted from intrinsic human islet cell signals, and was not dependent on the pancreatic environment or circulating human factors.. Recent studies suggest that insulin secretion by human islets may mature in an age-dependent manner (10), similar to findings in rodents (6-9). Using our transplant-based system, however, we found that ...

This protocols describes the generation of islet-like clusters. These islet clusters contain 2%-8% human c-peptide-positive cells, as well as glucagon- and somatostatin-positive cells. The insulin content measured in the islets is higher than that of human fetal islets. In addition, the islet clusters contain numerous secretory granules, as determined by electron microscopy, and secrete human c-peptide in a glucose-dependent manner ...

Background Islet 1 (ISL1), a LIM-homeodomain transcription factor is essential for promoting pancreatic islets proliferation and maintaining endocrine cells survival in embryonic and postnatal pancreatic islets. However, how ISL1 exerts the role in adult islets is, to date, not clear. Methodology/Principal Findings Our results show that ISL1 expression was up-regulated at the mRNA level both in cultured pancreatic cells undergoing glucose oxidase stimulation as well in type 1 and type 2 diabetes mouse models. The knockdown of ISL1 expression increased the apoptosis level of HIT-T15 pancreatic islet cells. Using HIT-T15 and primary adult islet cells as cell models, we show that ISL1 promoted adult pancreatic islet cell proliferation with increased c-Myc and CyclinD1 transcription, while knockdown of ISL1 increased the proportion of cells in G1 phase and decreased the proportion of cells in G2/M and S phases. Further investigation shows that ISL1 activated both c-Myc and CyclinD1 transcription through

TY - JOUR. T1 - Glucose-stimulated insulin secretion is coupled to the interaction of actin with the t-SNARE (target membrane soluble N-ethylmaleimide-sensitive factor attachment protein receptor protein) complex. AU - Thurmond, Debbie C.. AU - Gonelle-Gispert, Carmen. AU - Furukawa, Megumi. AU - Halban, Philippe A.. AU - Pessin, Jeffrey E.. PY - 2003/4/1. Y1 - 2003/4/1. N2 - The actin monomer sequestering agent latrunculin B depolymerized β-cell cortical actin, which resulted in increased glucose-stimulated insulin secretion in both cultured MIN6 β-cells and isolated rat islet cells. In perifused islets, latrunculin B treatment increased both first- and second-phase glucose-stimulated insulin secretion without any significant effect on total insulin content. This increase in secretion was independent of calcium regulation because latrunculin B also potentiated calcium-stimulated insulin secretion in permeabilized MIN6 cells. Confocal immunofluorescent microscopy revealed a redistribution of ...

Clinical islet transplantation, also known as beta cell replacement therapy, is currently used to treat some patients with T1D. Allogeneic islet cell transplantation is safe and has yielded success as measured by graft function, absence of hypoglycemic unawareness, normalized glycemic control, and partial to complete insulin independence in T1D patients across multiple centers. However, not all centers have been able to achieve the same level of success, especially in the long term [80]. The rate of success has been observed to be influenced by the experience of the personnel managing the islet isolation and transplantation procedures [81]. A long-term (,10 years) follow up of T1D patients that had undergone allogeneic islet cell transplantation revealed that the treated patients maintained some level of islet graft function, although this function decreased considerably over time [82]. A subset of patients required multiple islet transplants and very few of them had complete insulin ...

Because the beta cells in the pancreatic islets are selectively destroyed by an autoimmune process in type 1 diabetes, clinicians and researchers are actively pursuing islet transplantation as a means of restoring physiological beta cell function, which would offer an alternative to a complete pancreas transplant or artificial pancreas.[14][15] Islet transplantation emerged as a viable option for the treatment of insulin requiring diabetes in the early 1970s with steady progress over the last three decades.[16] Recent clinical trials have shown that insulin independence and improved metabolic control can be reproducibly obtained after transplantation of cadaveric donor islets into patients with unstable type 1 diabetes.[15] Islet transplantation for type 1 diabetes currently requires potent immunosuppression to prevent host rejection of donor islets.[17] An alternative source of beta cells, such insulin-producing cells derived from adult stem cells or progenitor cells would contribute to ...

The Ghrelin (ε) Cell Type Represents the Majority of Cells Within the Nkx2.2-/- Islet. To characterize the expanded ghrelin population in the Nkx2.2 mutant islet with respect to glucagon and the other islet hormones, we performed immunohistochemical analysis of the mutant islets. Similar to the wild-type islet, ghrelin-producing cells in the Nkx2.2 mutant islet do not coexpress insulin, somatostatin, or PP (Fig. 2 f, h, and i ). However, unlike its expression in wild-type islets, none of the ghrelin-producing cells in the Nkx2.2 mutant coexpress glucagon (Fig. 2g ). This would suggest that the ghrelin (ε) cell type is expanded, whereas the glucagon/ghrelin double-positive cells are absent from the Nkx2.2 mutant islet. Therefore, we conclude that, in normal islets, a population of glucagon-expressing α cells coexpress ghrelin, but approximately two-thirds of ghrelin-expressing cells define a new endocrine islet ε cell population. Moreover, in the Nkx2.2 mutant islet, the ghrelin-producing ε ...

TY - JOUR. T1 - Autocrine effect of Zn2+ on the glucose-stimulated insulin secretion. AU - Slepchenko, Kira G.. AU - Daniels, Nigel A.. AU - Aili, Guo. AU - Li, Yang V.. PY - 2015/9/25. Y1 - 2015/9/25. N2 - It is well known that zinc (Zn2+) is required for the process of insulin biosynthesis and the maturation of insulin secretory granules in pancreatic beta (β)-cells, and that changes in Zn2+ levels in the pancreas have been found to be associated with diabetes. Glucose-stimulation causes a rapid co-secretion of Zn2+ and insulin with similar kinetics. However, we do not know whether Zn2+ regulates insulin availability and secretion. Here we investigated the effect of Zn2+ on glucose-stimulated insulin secretion (GSIS) in isolated mouse pancreatic islets. Whereas Zn2+ alone (control) had no effect on the basal secretion of insulin, it significantly inhibited GSIS. The application of CaEDTA, by removing the secreted Zn2+ from the extracellular milieu of the islets, resulted in significantly ...

TY - JOUR. T1 - Enhanced de novo lipogenesis in the leptin-unresponsive pancreatic islets of prediabetic Zucker diabetic fatty rats. Role in the pathogenesis of lipotoxic diabetes. AU - Zhou, Yan Ting. AU - Shimabukuro, Michio. AU - Lee, Young H. AU - Koyama, Kazunori. AU - Higa, Moritake. AU - Ferguson, Tagan. AU - Unger, Roger H. PY - 1998. Y1 - 1998. N2 - Overaccumulation of fat in pancreatic islets of obese ZDF fa/fa rats is believed to cause β-cell failure and diabetes. Previously, we demonstrated that ZDF islets have an increased capacity to esterify fatty acids imported via the circulation. Here we examine the capacity of ZDF islets to synthesize fatty acids de novo. Compared with age-matched wild-type (+/+) control islets, acetyl CoA carboxylase (ACC) mRNA was fivefold and sixfold higher and fatty acid synthetase (FAS) was fourfold and sevenfold higher in prediabetic and diabetic ZDF islets, respectively. Incorporation of label from [14C]glucose into lipids was 84% higher in ZDF islets ...

TY - JOUR. T1 - Induction of uncoupling protein-2 mRNA by troglitazone in the pancreatic islets of Zucker Diabetic Fatty rats. AU - Shimabukuro, Michio. AU - Zhou, Yan Ting. AU - Lee, Young H. AU - Unger, Roger H. PY - 1997/8/18. Y1 - 1997/8/18. N2 - Because troglitazone, like leptin, lowers the triglyceride (TG) content of pancreatic islets, we searched for other leptinomimetic actions. Leptin upregulates the expression of uncoupling protein-2 (UCP-2) mRNA in islets of normal rats, but has no effect in islets of obese Zucker Diabetic Fatty (ZDF) rats with mutated leptin receptors. We report here that troglitazone also increases the UCP-2/β-actin mRNA ratio by 115% in wild type ZDF rats and by 400% in obese ZDF rats.. AB - Because troglitazone, like leptin, lowers the triglyceride (TG) content of pancreatic islets, we searched for other leptinomimetic actions. Leptin upregulates the expression of uncoupling protein-2 (UCP-2) mRNA in islets of normal rats, but has no effect in islets of obese ...

Global ICA (Islet Cell Antibody) ELISA(Enzyme immunoassay) Assay Kit Market Report 2021 has complete details about market of ICA (Islet Cell Antibody) ELISA(Enzyme immunoassay) Assay Kit industry, ICA (Islet Cell Antibody) ELISA(Enzyme immunoassay) Assay Kit analysis and current trends. Global ICA (Islet Cell Antibody) ELISA(Enzyme immunoassay) Assay Kit Market Report 2021 Full Report: 2350 USD Multi License (Section): 4700 USD Section Price: As below Page: 115 Chart and Figure: 124 Publisher: BisReport Delivery Time: 24 hour At the beginning of 2020, COVID-19 disease began to spread around the world, millions of people world.

Destruction or dysfunction in the human pancreatic islet affects at least 23.6 million affected individuals in the U.S. alone. The inability to regulate insulin production and maintain glucose homeostasis leads to a variety of severe diabetic complications at an estimated 2007 US health care cost of $174 billion dollars. Although medical management, lifestyle changes, and pharmacological agents are successful treatment tools for some, they are less effective, and have failed, in those with unstable diabetes, indicating that an urgent need for alternative therapies exist. Pancreatic islet transplantation is a form of cellular replacement therapy that has been shown to restore glycometabolic control and render some patients insulin independent. Our long term goal is to therefore improve human islet survival and transplantation success rates by understanding the factors affecting cell function in-vitro and in-vivo both in the native pancreas and transplant environments.; A survey of the challenges ...

Destruction or dysfunction in the human pancreatic islet affects at least 23.6 million affected individuals in the U.S. alone. The inability to regulate insulin production and maintain glucose homeostasis leads to a variety of severe diabetic complications at an estimated 2007 US health care cost of $174 billion dollars. Although medical management, lifestyle changes, and pharmacological agents are successful treatment tools for some, they are less effective, and have failed, in those with unstable diabetes, indicating that an urgent need for alternative therapies exist. Pancreatic islet transplantation is a form of cellular replacement therapy that has been shown to restore glycometabolic control and render some patients insulin independent. Our long term goal is to therefore improve human islet survival and transplantation success rates by understanding the factors affecting cell function in-vitro and in-vivo both in the native pancreas and transplant environments.; A survey of the challenges ...

The dynamics of the cationic, bioelectrical and secretory responses to formycin A were monitored in pancreatic islet cells in order to assess whether this adenosine analogue, which is known to be converted to formycin A 5-triphosphate in isolated islets, triggers the same sequence of ionic events as that otherwise involved in the process of nutrient-stimulated insulin release and currently attributed to an increase in adenosine 5-triphosphate (ATP) generation rate. Unexpectedly, formycin A first increased 86Rb outflow, decreased 45Ca outflow and inhibited insulin release from prelabelled islets perifused at physiological or higher concentrations of D-glucose. This early inhibitory effect of formycin A upon insulin release coincided, in perforated patch whole-cell recordings, with an initial transient increase of ATP-sensitive K+ channel activity. A positive secretory response to formycin A, still not associated with any decrease in K+ conductance, was only observed either immediately after formycin A

Bone marrow is currently being considered as an alternative site for pancreatic islet transplantation. The goal of the present review is to report preclinical and clinical studies taking advantage of this new implantation site. Preclinical studies in mice demonstrated that syngeneic islets could survive in bone marrow indefinitely with a higher success in providing euglycemia compared to islets transplanted into the traditionally used implantation site, namely, the liver. In concordant and discordant xenogeneic models, the immune response was more stringent when islets were transplanted to the bone marrow as compared to the traditional implantation site in rodents, the kidney capsule. As demonstrated by histology, cellular and humoral rejection was prevented by islets protected by micro-encapsulation in calcium-alginate beads, and a similar degree of fibrotic reaction was induced at both site, although functional studies in diabetic animals are still needed. In clinical settings, a pilot study ...

Two studies published in the current issue of Cell Transplantation (19:12) investigate frontiers of islet cell transplantation for treating diabetes. Researchers in Milan, Italy re-examine the role of bone marrow stem cells in diabetic therapy and islet cell regeneration and Canadian researchers offer improved strategies for optimizing pancreatic islet culture in vitro.. Both studies are in the current issue of Cell Transplantation, freely available on-line at http://www.ingentaconnect.com/content/cog/ct/.. New perspectives on role of bone marrow stem cells in islet transplantation. The role of bone marrow (BM)-derived stem cells in the islet cell regeneration process continues to evolve. A team of Italian researchers reports that employing BM-derived stem cells as feeder tissue, playing a protective role in supporting pancreatic islet repair for clinical use in treating diabetes, presents new therapeutic possibilities. Which cellular components of BM play the feeder role has not been ...

TY - THES. T1 - Beating diabetes: strategies to improve pancreatic islet transplantation. AU - Hilderink, J.. PY - 2013/10/17. Y1 - 2013/10/17. N2 - Type 1 diabetes is a chronic disease that is caused by nearly complete destruction of insulin producing beta-cells in the islets of Langerhans, affecting approximately 25 million people worldwide. Prior to the discovery of insulin, diabetes most certainly led to death. To date, patients with type 1 diabetes require daily insulin injections to control their blood glucose levels. Although this therapy is effective, it lacks precise glycemic control which on the long term increases the risk of developing life-threatening diseases such as heart disease, stroke, and kidney failure. Patients with type 1 diabetes who have had a kidney transplant or who suffer from severe hypoglycemia unawareness might benefit from intrahepatic transplantation of donor islets, according to the so-called Edmonton protocol. This procedure has worldwide been conducted over ...

TY - JOUR. T1 - Islet transplantation. T2 - Present and future perspectives. AU - Kenyon, Norma Sue. AU - Ranuncoli, Alessandra. AU - Masetti, Michele. AU - Chatzipetrou, Maria. AU - Ricordi, Camillo. PY - 1998. Y1 - 1998. N2 - Islet cell transplantation can potentially normalize blood glucose levels and stop the progression of clinical complications, and if the transplant is done early in the course of the disease complications may be prevented. Remarkable progress has been made in recent years and islet cell transplantation has resulted in normalization of metabolic control in several patients with Type 1 diabetes in the absence of hypoglycemia. Only a few patients, however, have achieved insulin independence. Issues relating to islet cell engraftment within the liver, prevention of rejection and recurrent autoimmunity, and identification of alternative immunosuppressive drugs that do not adversely affect islet cell function remain to be solved. Thus far, the need for chronic, generalized ...

Allogeneic islet transplantation faces difficulties because (i)organ shortage is recurrent; (ii) several pancreas donors are often needed to treat one diabetic recipient; and (iii) the intrahepatic site of islet implantation may not be the most appropriate site. Another source of insulin-producing cells, therefore, would be of major interest, and pigs represent a possible and serious source for obtaining such cells. Pig islet grafts may appear difficult because of the species barrier, but recent reports demonstrate that pig islets may function in primates for at least 6 months. Pig islet xenotransplantation, however, must still overcome several hurdles prior to becoming clinically applicable. The actual consensus is to produce more preclinical data in the pig-to-primate model as a necessary requirement to envisage any pig-to-human transplantation of islets; therefore, a summary of the actual acquired knowledge of pig islet transplantation in primates seemed useful. ...

The disappointing news is that we also discovered, much to our surprise, that the three immunosuppressive drugs commonly prescribed for patients after islet cell transplantation induced marked insulin resistance and beta cell toxicity in the models used in our studies, actually inducing diabetes and reducing the function of their new islet cells. This was true even though the doses and the blood levels of the drugs were low and comparable to those used in humans. In the study, the researchers used a common virus called an adenovirus to deliver hepatocyte growth factor (HGF), which induces beta cell division and prolongs beta cell survival, into pancreatic islets that had been extracted from rat pancreases. Having conducted similar previous research on genetically immunodeficient mice, researchers this time sought to construct a situation that most closely mimics a human islet cell transplant according to the Edmonton protocol. They used an allogenic islet transplant system, using islets from ...

Type 2 diabetes affects over 300 million people, causing severe complications and premature death, yet the underlying molecular mechanisms are largely unknown. Pancreatic islet dysfunction is central in type 2 diabetes pathogenesis, and understanding islet genome regulation could therefore provide valuable mechanistic insights. We have now mapped and examined the function of human islet cis-regulatory networks. We identify genomic sequences that are targeted by islet transcription factors to drive islet-specific gene activity and show that most such sequences reside in clusters of enhancers that form physical three-dimensional chromatin domains. We find that sequence variants associated with type 2 diabetes and fasting glycemia are enriched in these clustered islet enhancers and identify trait-associated variants that disrupt DNA binding and islet enhancer activity. Our studies illustrate how islet transcription factors interact functionally with the epigenome and provide systematic evidence that the

TY - JOUR. T1 - I-45 islet cell antigen is a 68KD neuroendocrine protein. AU - Raju, R.. AU - Srikanta, S.. AU - Shah, P.. AU - Kochupillai, N.. PY - 1995/1/1. Y1 - 1995/1/1. N2 - A monoclonal antibody approach was used to characterize islet cell differentiation antigens involved in autoimmunity related diabetes mellitus. This procedure yielded islet cell monoclonal antibodies (ICMAbs)that demonstrated varying tissue/cellular distribution. The ICMAb I-45 showed a pan-islet reactivity similar to the reactivity of islet cell autoantibodies. The target antigen of the ICMAb I-45 demonstrated a neuroendocrine distribution. Single step immunoaffinity purification of I-45 antigen using I-45 monoclonal antibody immunoaffinity matrix yielded a 68kD protein. The specificity of the immunoaffinity purified 68kD protein was further demonstrated by the lack of binding of this protein to immunoaffinity columns of irrelevant monoclonal antibodies. The neuroendocrine distribution of the I-45 antigen, like that ...

Lab Reagents Igg Antibody Laboratories manufactures the islet cell antibody igg reagents distributed by Genprice. The Islet Cell Antibody Igg reagent is RUO (Research Use Only) to test human serum or cell culture lab samples. To purchase these products, for the MSDS, Data Sheet, protocol, storage conditions/temperature or for the concentration, please contact igg antibody. Other Islet products are available in stock. Specificity: Islet Category: Cell Group: Antibody Igg. Antibody Igg information ...

TY - JOUR. T1 - Olmesartan and temocapril prevented the development of hyperglycemia and the deterioration of pancreatic islet morphology in Otsuka-Long-Evans-Tokushima Fatty rats. AU - Kaihara, Masanobu. AU - Nakamura, Yoshio. AU - Sugimoto, Taro. AU - Uchida, Haruhito A.. AU - Norii, Hisanao. AU - Hanayama, Yoshihisa. AU - Makino, Hirofumi. PY - 2009/2/1. Y1 - 2009/2/1. N2 - We investigated the impact of olmesartan and temocapril on pancreatic islet β-cells during the development of diabetes mellitus using Otsuka-Long-Evans-Tokushima Fatty (OLETF) rats. Four-week-old male OLETF rats were fed standard chow (untreated: n = 5), or chow containing either 0.005% olmesartan (n = 5) or 0.01 % temocapril (n = 5) until being sacrificed at 35 weeks of age. Pancreas sections were double-stained with anti-insulin and anti-glucagon antibodies. The percent areas of β-cells, α-cells and non-α-non-β-cells were compared among groups. In untreated OLETF rats, the fasting plasma glucose (FPG) level was ...

Ex vivo expansion of endocrine cells constitutes an interesting alternative to be able to match the unmet need of transplantable pancreatic islets. However, endocrine cells become fragile once removed from their extracellular matrix (ECM) and typically become senescent and loose insulin expression during conventional 2D culture. Herein we develop a protocol where 3D silk matrices functionalized with ECM derived motifs are used for generation of insulin-secreting islet-like clusters from mouse and human primary cells. The obtained clusters were shown to attain an islet-like spheroid shape and to maintain functional insulin release upon glucose stimulation in vitro. Furthermore, in vivo imaging of transplanted murine clusters showed engraftment with increasing vessel formation during time. There was no sign of cell death and the clusters maintained or increased in size throughout the period, thus suggesting a suitable cluster size for transplantation.. ...

1. Measurements of membrane capacitance, as an indicator of exocytosis, and intracellular Ca2+ concentration ([Ca2+]i) were used to determine the Ca2+ dependence of secretion in single pancreatic B-cells. 2. Exocytosis was dependent on a rise in [Ca2+]i and could be evoked by activation of voltage-dependent Ca2+ currents. The threshold for depolarization-induced release was 0.5 microM [Ca2+]i. Once the [Ca2+]i threshold was exceeded, exocytosis was rapidly (| 50 ms) initiated. When individual pulses were applied, exocytosis stopped immediately upon repolarization and the Ca2+ channels closed, although [Ca2+]i remained elevated for several seconds. 3. During repetitive stimulation (1 Hz), when [Ca2+]i attained micromolar levels, exocytosis also took place during the interpulse intervals albeit at a slower rate than during the depolarizations. 4. Exocytosis could be initiated by simulated action potentials. Whereas a single action potential only produced a small capacitance increase, and in some cells

TY - JOUR. T1 - Beneficial effects of inhibition of soluble epoxide hydrolase on glucose homeostasis and islet damage in a streptozotocin-induced diabetic mouse model. AU - Chen, Lingdan. AU - Fan, Cheng. AU - Zhang, Yi. AU - Bakri, Mahinur. AU - Dong, Hua. AU - Morisseau, Christophe. AU - Maddipati, Krishna Rao. AU - Luo, Pengcheng. AU - Wang, Cong Yi. AU - Hammock, Bruce D.. AU - Wang, Mong Heng. PY - 2013/7. Y1 - 2013/7. N2 - Soluble epoxide hydrolase (sEH) is an enzyme involved in the metabolism of endogenous inflammatory and anti-apoptotic mediators. In the present study, we determined the effects of the inhibition of sEH on glucose homeostasis and islet damage in mice treated with streptozotocin (STZ), a model of chemical-induced diabetes. STZ increased daily water intake and decreased visceral (spleen and pancreas) weight in mice; sEH inhibition in STZ mice decreased water intake, but did not affect visceral weight. Hyperglycemia induced by STZ treatment in mice was attenuated by ...

Diabetic Mouse Pancreatic Islets are tested for their viability using FDA/PI, purity using Dithizone staining, static insulin secretion in response to 14 mM glucose. Upon request, dynamic insulin secretion and calcium imaging in response to glucose and other stimulators can be performed ...

88682 avhandlingar från svenska högskolor och universitet. Avhandling: Pancreatic Islet Transplantation Modifications of Islet Properties to Improve Graft Survival.

TY - JOUR. T1 - Islet β-cell-specific MafA transcription requires the 5′-Flanking conserved region 3 control domain. AU - Raum, Jeffrey C.. AU - Hunter, Chad S.. AU - Artner, Isabella. AU - Henderson, Eva. AU - Guo, Min. AU - Elghazi, Lynda. AU - Sosa-Pineda, Beatriz. AU - Ogihara, Takeshi. AU - Mirmira, Raghavendra G.. AU - Sussel, Lori. AU - Stein, Roland. PY - 2010/9. Y1 - 2010/9. N2 - MafA is a key transcriptional activator of islet β cells, and its exclusive expression within β cells of the developing and adult pancreas is distinct among pancreatic regulators. Region 3 (base pairs -8118 to -7750 relative to the transcription start site), one of six conserved 5′ cis domains of the MafA promoter, is capable of directing β-cell-line-selective expression. Transgenic reporters of region 3 alone (R3), sequences spanning regions 1 to 6 (R1-6; base pairs -10428 to +230), and R1-6 lacking R3 (R1-6 ΔR3) were generated. Only the R1-6 transgene was active in MafA+ insulin+ cells during ...

article{4bc73d87-e463-4daf-8534-3032bbd37e50, abstract = {,p,Islet transplantation is a minimally invasive β-cell replacement strategy. Islet transplantation is a reimbursed treatment in Norway. Here, we summarize the cost and clinical outcome of 31 islet transplantations performed at Oslo University Hospital (OUS) from January 2010 to June 2015. Patients were retrospectively divided into three groups. Thirteen patients received either one or two islet transplantation alone (ITA), while five patients received islet transplantation after previous solid organ transplantation. For the group receiving 2 ITA, Kaplan-Meier estimates show an insulin independence of 20% more than 4 years after their last transplantation. An estimated 70% maintain at least partial graft function, defined as fasting C-peptide >0.1 nmol L,sup,−1,/sup,, and 47% maintain a HbA1c below 6.5% or 2 percent points lower than before ITA. For all groups combined, we estimate that 44% of the patients have a 50% reduction in ...

Glucose-induced insulin secretion from pancreatic islets requires metabolism of glucose within islet β-cells, and ATP has attracted interest as a messenger of glucose metabolism within β-cells. Glucose-induced insulin secretion from islets and HIT insulinoma cells is accompanied by activation of an ATP-stimulatable Ca2+-independent phospholipase A2 (ASCI-PLA2) enzyme, the catalytic activity of which resides in a 40 kDa protein. An analogous PLA2 enzyme in myocardium was recently found to consist of a complex of a 40 kDa catalytic protein with a tetramer of an isoform of the glycolytic enzyme phosphofructokinase (PFK). Association of the PFK isoform with the myocardial PLA2 catalytic protein was found to confer ATP sensitivity onto the enzyme complex. Here we demonstrate that the majority of HIT cell and islet ASCI-PLA2 catalytic activity elutes from a gel filtration column in a region corresponding to 400 kDa, suggesting that the 40 kDa β-cell ASCI-PLA2 catalytic protein exists as part of a ...

Defines pancreatic islets and describes the process of pancreatic islet transplantation, an experimental procedure. also discusses the risks and benefits of.

We have investigated the in vitro effects of increased levels of glucose and free fatty acids on autophagy activation in pancreatic beta cells. INS-1E cells and isolated rat and human pancreatic islets were incubated for various times (from 2 to 24 h) at different concentrations of glucose and/or palmitic acid. Then, cell survival was evaluated and autophagy activation was explored by using various biochemical and morphological techniques. In INS-1E cells as well as in rat and human islets, 0.5 and 1.0 mM palmitate markedly increased autophagic vacuole formation, whereas high glucose was ineffective alone and caused little additional change when combined with palmitate. Furthermore, LC3-II immunofluorescence co-localized with that of cathepsin D, a lysosomal marker, showing that the autophagic flux was not hampered in PA-treated cells. These effects were maintained up to 18-24 h incubation and were associated with a significant decline of cell survival correlated with both palmitate concentration and

Defines pancreatic islets and describes the process of pancreatic islet transplantation and the risks and benefits of transplantation.​

Successful pancreas preservation during storage in oxygenated perfluorodecalin (PFD) is mainly related to oxidative ATP generation during storage. Increasing the storage temperature would accelerate this process essential for resuscitation of ischemically damaged pancreatic tissue. The present study aimed at comparing islet isolation outcome from adult pig pancreata preserved in oxygenated PFD by means of a one-layer method during storage on ice or at 20 degrees C. Resected pancreata were intraductally flushed with cold UW solution and promptly processed (n = 6) or stored for 3 h in continuously oxygenated PFD at 4 degrees C (n = 5) or 20 degrees C (n = 7). Prior to digestion-filtration pancreata were intraductally injected with UW supplemented with Serva collagenase NB8 and neutral protease. Islet quality assessment determined viability, glucose stimulation index, mitochondrial activity, intracellular ATP content, and transplant function in diabetic nude mice. Pancreata oxygenated for 3 h at 20 degrees

Analysis of MafB(-/-) mice has suggested that the MAFB transcription factor was essential to islet α- and β-cell formation during development, although the postnatal physiological impact could not be studied here because these mutants died due to problems in neural development. Pancreas-wide mutant mice were generated to compare the postnatal significance of MafB (MafB(Δpanc)) and MafA/B (MafAB(Δpanc)) with deficiencies associated with the related β-cell-enriched MafA mutant (MafA(Δpanc)). Insulin(+) cell production and β-cell activity were merely delayed in MafB(Δpanc) islets until MafA was comprehensively expressed in this cell population. We propose that MafA compensates for the absence of MafB in MafB(Δpanc) mice, which is supported by the death of MafAB(Δpanc) mice soon after birth from hyperglycemia. However, glucose-induced glucagon secretion was compromised in adult MafB(Δpanc) islet α-cells. Based upon these results, we conclude that MafB is only essential to islet α-cell ...

Bysani M, Agren R, Davegårdh C, Volkov P, Rönn T, Unneberg P, Bacos K, Ling C Sci Rep 9 (1) - [2019-12-00; online 2019-05-23] Impaired insulin secretion from pancreatic islets is a hallmark of type 2 diabetes (T2D). Altered chromatin structure may contribute to the disease. We therefore studied the impact of T2D on open chromatin in human pancreatic islets. We used assay for transposase-accessible chromatin using sequencing (ATAC-seq) to profile open chromatin in islets from T2D and non-diabetic donors. We identified 57,105 and 53,284 ATAC-seq peaks representing open chromatin regions in islets of non-diabetic and diabetic donors, respectively. The majority of ATAC-seq peaks mapped near transcription start sites. Additionally, peaks were enriched in enhancer regions and in regions where islet-specific transcription factors (TFs), e.g. FOXA2, MAFB, NKX2.2, NKX6.1 and PDX1, bind. Islet ATAC-seq peaks overlap with 13 SNPs associated with T2D (e.g. rs7903146, rs2237897, rs757209, rs11708067 and ...

In this study, the initial experience of the authors using the lower rectum as a novel site for transplantation of free islets is reported. The reasons for selecting the rectum as a potential site are, firstly, that there is a rich plexus of veins draining into the portal venous system, secondly, that it is safe and convenient for access, both for grafting procedures and biopsies and thirdly, that repeat procedures are possible. About 1500 intact islets from three donor PVG rat pancreases were implanted, using an injection technique,into the submucosa of the lower rectum circumferentially above the dentate line of recipient syngeneic PVG rats (n=31). Biopsy of these transplanted islets showed revascularisation of islet clusters in the submucosa of the rectum for greater than 60 days. Clinical trials of islet cell grafting have commenced worldwide over the last 18 months, and this study describes a simple technique for islet cell grafting which could potentially be applied in diabetic patients. ...

TY - JOUR. T1 - Auto- and alloimmune reactivity to human islet allografts transplanted into type 1 diabetic patients. AU - Roep, Bart O.. AU - Stobbe, Inge. AU - Duinkerken, Gaby. AU - Van Rood, Jon J.. AU - Lernmark, Åke. AU - Keymeulen, Bart. AU - Pipeleers, Danny. AU - Claas, Frans H.J.. AU - De Vries, René R.P.. PY - 1999/1/1. Y1 - 1999/1/1. N2 - Allogeneic islet transplantation can restore an insulin-independent state in C-peptide-negative type 1 diabetic patients. We recently reported three cases of surviving islet allografts that were implanted in type 1 diabetic patients under maintenance immune suppression for a previous kidney graft. The present study compares islet graft-specific cellular auto- and alloreactivity in peripheral blood from those three recipients and from four patients with failing islet allografts measured over a period of 6 months after portal islet implantation. The three cases that remained C-peptide- positive for ,1 year exhibited no signs of alloreactivity, and ...

DESCRIPTION (provided by applicant): Clinical islet transplantation (CIT), the infusion of allogeneic islets into the liver, has shown significant promise in the long-term treatment of Type diabetes by providing a cell-based means to mimic the normal physiological response to glucose. While promising, it is dampened by the impaired function and loss of islets following implantation. This loss is attributed to strong inflammatory and immunological responses to the transplant, primarily instigated by cell surface proteins and antigens. In this application, we see to minimize detrimental host responses that lead to islet engraftment failure by encapsulating the islets in novel ultrathin polymeric layers. Ultrathin coatings are generated through the covalent layer-by-layer assembly of biomaterials functionalized with bioorthogonal chemical handles. Through the controlled, covalent linking of polymers layers on the islet cell cluster surface, resulting stable capsules are on the order of 500-fold ...

In both recipient groups - those receiving an initial islet transplant in either the eye or the kidney along with the short-term treatment with the anti-CD154 antibody - results showed immunosuppression-free islet survival for more than 300 days.. Notably, of the group that initially received islet transplants in the eye, more than 70 percent exhibited survival of the second islet transplant in the kidney for more than 400 days without continued immunosuppression, compared to 30 percent of the recipients that initially received islets in their kidney.. Additional studies in the preclinical model showed reduced donor-specific immune reactivity in the blood, consistent with induced peripheral immune tolerance.. Researchers conclude the preliminary findings in these study models of diabetes demonstrate the establishment of immune tolerance towards transplanted islets and their long-term protection from immune attack long after stopping anti-rejection therapy.. They acknowledge that further testing ...