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| 2. |
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| 3. |
- Andersson, Annika K., et al.
(författare)
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Cytokine-induced PGE2 formation is reduced from iNOS deficient murine islets
- 2004
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 0303-7207 .- 1872-8057. ; 220:1-2, s. 21-29
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Tidskriftsartikel (refereegranskat)abstract
- Cytokines may be involved in islet destruction during Type 1 diabetes. Exposure to interleukin-1beta (IL-1beta) or IL-1beta plus interferon-gamma (IFN-gamma) of rodent islets induces expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Subsequent formation of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) may impair beta-cell function. Using iNOS deficient (iNOS -/-) islets, we have further investigated the relation between NO formation and PGE(2) induction. We found that iNOS -/- islets responded with a reduced PGE(2) formation following IL-1beta or (IL-1beta + IFN-gamma) treatment compared to wild-type (wt) islets, while COX-2 mRNA or protein content were unchanged. By the addition of an NO donor together with IL-1beta, PGE(2) formation could be stimulated from iNOS -/- islets. We conclude that the lowered capacity of PGE(2) formation observed from cytokine exposed iNOS -/- islets is due to a decreased stimulation of PGE(2) formation by the COX-2 enzyme in the absence of NO, rather then differences in expressed COX-2 protein.
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| 4. |
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| 5. |
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| 7. |
- Andersson, Annika K., 1974-
(författare)
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Role of Inducible Nitric Oxide Synthase and Melatonin in Regulation of β-cell Sensitivity to Cytokines
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The mechanisms of β-cell destruction leading to type 1 diabetes are complex and not yet fully understood, but infiltration of the islets of Langerhans by autoreactive immune cells is believed to be important. Activated macrophages and T-cells may then secrete cytokines and free radicals, which could selectively damage the β-cells. Among the cytokines, IL-1β, IFN-γ and TNF-α can induce expression of inducible nitric synthase (iNOS) and cyclooxygenase-2. Subsequent nitric oxide (NO) and prostaglandin E2 (PGE2) formation may impair islet function.In the present study, the ability of melatonin (an antioxidative and immunoregulatory hormone) to protect against β-cell damage induced by streptozotocin (STZ; a diabetogenic and free radical generating substance) or IL-1β exposure was examined. In vitro, melatonin counteracted STZ- but not IL-1β-induced islet suppression, indicating that the protective effect of melatonin is related to interference with free radical generation and DNA damage, rather than NO synthesis. In vivo, non-immune mediated diabetes induced by a single dose of STZ was prevented by melatonin.Furthermore, the effects of proinflammatory cytokines were examined in islets obtained from mice with a targeted deletion of the iNOS gene (iNOS -/- mice) and wild-type controls. The in vitro data obtained show that exposure to IL-1β or (IL-1β + IFN-γ) induce disturbances in the insulin secretory pathway, which were independent of NO or PGE2 production and cell death. Initially after addition, in particular IL-1β seems to be stimulatory for the insulin secretory machinery of iNOS –/- islets, whereas IL-1β acts inhibitory after a prolonged period. Separate experiments suggest that the stimulatory effect of IL-1β involves an increased gene expression of phospholipase D1a/b. In addition, the formation of new insulin molecules appears to be affected, since IL-1β and (IL-1β + IFN-γ) suppressed mRNA expression of both insulin convertase enzymes and insulin itself.
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| 8. |
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| 9. |
- Anvari, Ebrahim, et al.
(författare)
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The H1-receptor antagonist cetirizine ameliorates high-fat diet-induced glucose intolerance in male C57BL/6 mice, but not diabetes outcome in female non-obese diabetic (NOD) mice
- 2015
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Ingår i: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 120:1, s. 40-46
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Tidskriftsartikel (refereegranskat)abstract
- Background. It has been proposed that the histamine 1-receptor (H1-receptor) not only promotes allergic reactions, but also modulates innate immunity and autoimmune reactions. In line with this, we have recently reported that the H1-receptor antagonist cetirizine partially counteracts cytokine-induced beta-cell signaling and destruction. Therefore, the aim of this study was to determine whether cetirizine affects diabetes in NOD mice, a model for human type 1 diabetes, and glucose intolerance in high-fat diet C57BL/6 mice, a model for human glucose intolerance. Methods. Female NOD mice were treated with cetirizine in the drinking water (25 mg/kg body weight) from 9 until 30 weeks of age during which precipitation of diabetes was followed. Male C57BL/6 mice were given a high-fat diet from 5 weeks of age. When the mice were 12 weeks of age cetirizine was given for 2 weeks in the drinking water. The effects of cetirizine were analyzed by blood glucose determinations, glucose tolerance tests, and insulin sensitivity tests. Results. Cetirizine did not affect diabetes development in NOD mice. On the other hand, cetirizine treatment for 1 week protected against high-fat diet-induced hyperglycemia. The glucose tolerance after 2 weeks of cetirizine treatment was improved in high-fat diet mice. We observed no effect of cetirizine on the insulin sensitivity of high-fat diet mice. Conclusion. Our results suggest a protective effect of cetirizine against high-fat diet-induced beta-cell dysfunction, but not against autoimmune beta-cell destruction.
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| 10. |
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| 11. |
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| 12. |
- Blixt, Martin, 1977-, et al.
(författare)
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Characterization of β-cell function of pancreatic islets isolated from bank voles developing glucose intolerance/diabetes : an animal model showing features of both type 1 and type 2 diabetes mellitus, and a possible role of the Ljungan virus
- 2007
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Ingår i: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480 .- 1095-6840. ; 154:1-3, s. 41-47
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Tidskriftsartikel (refereegranskat)abstract
- Bank voles (Clethrionomys glareolus) kept in captivity develop diabetes mellitus to a significant extent. Also in wild bank voles, elevated blood glucose has been observed. A newly isolated picornavirus named Ljungan virus (LV) has been found in the pancreas of these bank voles. Moreover, LV infection in combination with environmental factors may cause glucose intolerance/diabetes (GINT/D) in normal mice. The aim of the present study was to investigate the functional characteristics of pancreatic islets, isolated from bank voles, bred in the laboratory but considered LV infected. About 20% of all males and females were classified as GINT/D following a glucose tolerance test. Of these animals the majority had become diabetic by 20 weeks of age, with a tendency towards an earlier onset in the males. GINT/D animals had increased serum insulin levels. Islets were tested on the day of isolation (day 0) and after 1 week of culture for their insulin content and their capacity to synthesize (pro)insulin, secrete insulin and metabolize glucose. Functional differences could be observed between normal and GINT/D animals as well as between genders. An elevated basal insulin secretion was observed on day 0 indicating β-cell dysfunction among islets isolated from diabetic males. In vitro culture could reverse some functional changes. The increased serum insulin level and the increased basal islet insulin secretion may suggest that the animals had developed a type 2 diabetes-like condition. It is likely that the putative stress imposed in the laboratory, maybe in combination with LV infection, can lead to an increased functional demand on the β-cells.
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| 13. |
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| 14. |
- Blixt, Martin, et al.
(författare)
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Pancreatic islets of bank vole show signs of dysfunction after prolonged exposure to high glucose concentrations in vitro
- 2010
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Ingår i: Journal of Endocrinology. - 0022-0795 .- 1479-6805. ; 206:1, s. 47-54
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Tidskriftsartikel (refereegranskat)abstract
- Bank voles develop glucose intolerance/diabetes mellitus when kept in captivity. We have characterized beta-cell function of glucose intolerant/diabetic animals, and found that this animal model has features of both human type 1 and type 2 diabetes. The aim of this study was to study the functional alterations of islets isolated from glucose tolerant bank voles after a prolonged exposure to various glucose concentrations in vitro. For this purpose, pancreatic islets from normal (glucose tolerant) male and female bank voles were cultured at different glucose concentrations (5.6, 11.1 (control), or 28 mM) whereupon islet functions were examined. Overall, islet insulin output was lowered at 5.6 mM glucose, and similar to control, or enhanced after culture in 28 mM glucose. High glucose culture led to decreased insulin contents, but there was no change in islet DNA content and in morphological assessments of cell death, with the latter findings suggesting that the so-called glucotoxicity had not evolved. A slight gender difference was observed in that islets isolated from females exhibited a glucose-regulated (pro) insulin biosynthesis rate and insulin gene expression. In conclusion, we have found that islets isolated from female and male bank voles are affected by glucose concentrations in vitro in that some signs of dysfunction were observed upon high glucose exposure. A minor gender difference was observed suggesting that the islets of the females may more readily adapt to the elevated glucose concentration than islets of the male bank voles. It could be that these in vitro gender differences observed may represent a mechanism underlying the gender difference in diabetes development observed among bank voles. Journal of Endocrinology (2010) 206, 47-54
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| 15. |
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| 16. |
- Blixt, Martin, 1977-, et al.
(författare)
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Suppression of bank vole pancreatic islet function by proinflammatory cytokines
- 2009
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 0303-7207 .- 1872-8057. ; 305:1-2, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- Bank voles kept in captivity may develop diabetes. We recently characterized beta-cell function of pancreatic islets from normal and glucose intolerant/diabetic bank voles. These animals had features of both human type 1 and type 2 diabetes. Cytokines may impair β-cell function in both types of diabetes. Presently, we studied how pancreatic islets isolated from normal, i.e. glucose tolerant bank voles are affected by proinflammatory cytokines in vitro. Islets were exposed to hIL-1β (25U/ml) alone or in combination with hTNF-α (1000U/ml)+mIFN-γ (1000U/ml) for 48h, whereupon islet functions were assessed. Cytokines markedly reduced insulin gene expression and the (pro)insulin biosynthesis rate, which was accompanied by a profound depletion of the islet insulin content. The cytokines did not affect the culture medium insulin accumulation and the glucose oxidation rate, but caused a modest increase in medium nitrite, an indicator of nitric oxide (NO) generation. Cytokine-induced decrease in islet insulin content was not prevented by the preferential inducible NO synthase inhibitor aminoguanidine. These findings suggest that the reduction in islet insulin content is not attributed to enhanced exocytosis or related to altered glucose metabolism, but is rather due to a decline in insulin production. The suppressive effects of islet functions elicited by cytokines seem to be mediated by an NO-independent mechanism. In relation to previous studies on cytokine effects on islets from various species, the bank vole islets show a pattern which more resembles human islets than rat or murine islets.
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| 17. |
- Blixt, Martin, 1977-
(författare)
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The bank vole (Myodes glareolus) – a novel animal model for the study of diabetes mellitus
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The bank vole (Microtus arvalis) develops glucose intolerance both when kept in captivity and in the wild state. Glucose intolerant bank voles kept in captivity exhibited polydipsia, polyuria, hyperglycemia, hyperinsulinemia, islet autoantibodies and a markedly changed islet structure resembling so–called hydropic degeneration. Islets showing hydropic degeneration have reduced β–cell mass. However, the relative islet size to total pancreas area was not changed. Pancreatic islet isolated from glucose intolerant bank voles had an altered islet function showing signs of being exposed to an increased functional demand on their β–cells. Also, islets from male bank voles seem more affected than the islets from females. Islets isolated from glucose tolerant male bank voles cultured for 5 days at 28 mM glucose did not reveal any change in insulin gene expression or insulin biosynthesis rate. However, islets from female bank voles displayed a glucose concentration dependent response. This suggests that there is gender difference in that, islets of female more easily than islets of males adapt to elevated glucose concentration. Furthermore, islets isolated from glucose tolerant males had reduced insulin gene expression after exposure to proinflammatory cytokines for 48 hrs. This effect seemed to be NO-independent since only a minor elevation of nitrite accumulation in the medium was seen, and the use of iNOS inhibitor could not counteract the cytokine effect. The observed response seen in bank vole islets upon exposure to various glucose concentrations or proinflammatory cytokines is similar to those seen in studies of human islets. The bank vole may therefore represent a novel animal model for the study of diabetes. An unresolved issue is the role of the Ljungan virus which is found in the bank vole colony. Bank voles developing glucose intolerance display features of both human type 1 and type 2 diabetes, where environmental factors seems to play an important role as determinant. Our findings suggest that bank voles bred in the laboratory may develop more of a type 2 diabetes. However, bank voles caught in nature instead may rather develop a type 1 form of the disease.
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| 18. |
- Bohman, Sara, 1981-
(författare)
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Microencapsulation of Pancreatic Islets : A Non-Vascularised Transplantation Model
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Transplantation of pancreatic islets is a potential treatment of type 1 diabetes that aims to restore normal blood glucose control. By encapsulating the islets in alginate, they can be protected from rejection. The aim of this thesis was to study the biology of encapsulated islets and to use the technique of microencapsulation to study the effect of transplantation in a system that is separated from direct contact with the vascular system and the host tissue at the transplantation site.Encapsulated islets can effectively reverse hyperglycaemia after transplantation into the peritoneal cavity of diabetic mice. A period of culture before encapsulation and transplantation did not affect their insulin release or curative capability. Pre-culture with exendin-4 improved insulin secretion, but not to the extent that the long term outcome in our transplantation model was improved. Despite being able to reach and retain normoglycaemia, microencapsulated islets transplanted intraperitoneally decreased in size. More specifically the number of beta cells in each individual islet was decreased. However, in contrast to previous studies using non-encapsulated islets, the alpha cell number was maintained, and thus the capsule seems to protect these peripherally located and otherwise exposed cells. As the capsule also prevents revascularisation of the islets, the model was used to study the importance of vascular supply for islet amyloid formation. Islet amyloid is a possible reason for the long-term failure of transplanted islets. It is likely that their low vascular density causes a disturbed local clearance of IAPP and insulin that starts the aggregation of IAPP. Indeed, encapsulated islets had an accelerated amyloid formation compared to normal islets, and might serve as a model for further studies of this process.In conclusion, although revascularisation is not a prerequisite for islet graft function, it plays an important role for islet transplantation outcome.
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| 19. |
- Börjesson, Andreas, et al.
(författare)
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beta-cell specific overexpression of suppressor of cytokine signalling-3 does not protect against multiple low dose streptozotocin induced type 1 diabetes in mice
- 2011
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Ingår i: Immunology Letters. - : Elsevier BV. - 0165-2478 .- 1879-0542. ; 136:1, s. 74-79
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the impact of beta-cell specific overexpression of suppressor of cytokine signalling-3 (SOCS-3) on the development of multiple low dose streptozotocin (MLDSTZ) induced Type 1 diabetes and the possible mechanisms involved. MLDSTZ treatment was administered to RIP-SOCS-3 transgenic and wild-type (wt) mice and progression of hyperglycemia monitored. Isolated islets from both strains were exposed to human IL-1 beta (25 U/ml) or a combination of human IL-1 beta (25 U/ml) and murine IFN-gamma (1000 U/ml) for 24h or 48h and we investigated the expression of IL-1 receptor antagonist (IL-1Ra) mRNA in islet cells and secretion of IL-1Ra into culture medium. MLDSTZ treatment caused gradual hyperglycemia both in the wt mice and in the transgenic mice with the latter tending to be more sensitive. In vitro experiments on wt and transgenic islets did not reveal any differences in sensitivity to damaging effects of STZ. Exposure of wt islets to 1L-1 beta or IL-1 beta + IFN-gamma seemed to lead to a failing IL-1Ra response from SOCS-3 transgenic islets. It could be that an increased expression of a possible protective molecule against beta-cell destruction may lead to a dampered response of another putative protective molecule. This may have counteracted a protective effect against MLDSTZ in SOCS-3 transgenic mice.
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| 20. |
- Börjesson, Andreas, 1976-
(författare)
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Investigations of Strategies to Counteract Proinflammatory Cytokines in Experimental Type 1 Diabetes
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Type 1 diabetes (T1D) is a chronic autoimmune disease targeted against the pancreatic β-cells. Proinflammatory cytokines are considered to play a major role in the destruction of the insulin-producing β-cells. This thesis studied strategies to counteract proinflammatory cytokines in experimental T1D. Both animal models for T1D as well as β-cell preparations exposed in vitro to putative noxious conditions were examined.In the first study we observed that cytokine treatment of mouse pancreatic islets lacking inducible nitric oxide synthase (iNOS) induced a prolongation of the early stimulatory phase of glucose stimulated insulin secretion. Various experiments led to the conclusion that this prolonged stimulatory effect may involve the DAG/PLD/PKC pathway.Next, we transplanted mouse islets deficient in iNOS to spontaneously diabetic NOD mice. We observed a normalization of hyperglycemia but not a delayed allograft rejection compared to transplanted wild type islets. Thus, absence of iNOS in the graft was not sufficient to prolong allograft survival.In paper III we found that sustained glucose stimulation of rat pancreatic islets was coupled to a decreased conversion of proinsulin to insulin. Islet treatment with IL-1β was also coupled to a decreased proinsulin conversion. Islet proconvertase activity may be a target in islet damage.In paper IV prolactin (PRL) was administered to mice in the multiple low dose streptozotocin model and we observed that PRL enhanced a Th2 response. This may contribute to the protective action by PRL in this model of autoimmune T1D.Finally, by examining β-cells overexpressing Suppressor of cytokine signalling 3 (SOCS-3) it was found that this could inhibit IL-1β induced signalling through the NF-κB and MAPK pathways. SOCS-3 overexpression also inhibited apoptosis induced by cytokines in primary β-cells. Lastly, we demonstrated that SOCS-3 transgenic islets were protected in an allogeneic transplantation model.
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| 21. |
- Börjesson, Andreas, et al.
(författare)
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Survival of an islet allograft deficient in iNOS after implantation into diabetic NOD mice
- 2006
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Ingår i: Cell Transplantation. - 0963-6897 .- 1555-3892. ; 15:8-9, s. 769-775
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Tidskriftsartikel (refereegranskat)abstract
- Proinflammatory cytokines play a major role in rejection of pancreatic islet allografts and in type 1 diabetes (T1D). In rodent islets, exposure to IL-1β alone or combined with IFN-γ induces expression of inducible nitric oxide synthase (iNOS). Inhibition of iNOS or a deletion of the iNOS gene has been shown to be protective in animal models of T1D. In the present study we tested the hypothesis that transplantation of pancreatic islets deficient in iNOS (iNOS-/-) would permit increased graft survival. Pancreatic islets isolated from wild-type (wt) mice and iNOS-/- mice were allogeneically transplanted beneath the kidney capsule of spontaneously diabetic NOD mice. When blood glucose increased above 12.0 mM after preceding normalization of hyperglycemia, animals were sacrificed. Histological examinations of grafts were performed and graft gene expression was analyzed by real-time PCR. Transplantations of the two types of islets could reverse hyperglycemia and the grafts functioned for on average 1 week posttransplantation. Morphological examination of both types of islet grafts showed immune cell infiltration around and within the grafts. Remaining endocrine cells could be observed in wt and iNOS-/- islet grafts. In the removed grafts iNOS-/- islet tissue contained higher mRNA levels of insulin, proinsulin convertases (PC-1 and PC-2), and IL-1β compared to transplanted wt islets. The assessments of insulin, PC-1 and PC-2 mRNAs of the grafts suggest that the iNOS-/- islets may be more resistant to destruction in the transplantation model used; however, this was not sufficient to prolong the period of normoglycemia posttransplantation.
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| 22. |
- Carlsson, Annika, et al.
(författare)
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Concomitant Enzyme-Linked Immunosorbent Assay Measurements of Rat Insulin, Rat C-Peptide, and Rat Proinsulin from Rat Pancreatic Islets : Effects of Prolonged Exposure to Different Glucose Concentrations
- 2010
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Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 151:10, s. 5048-5052
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Tidskriftsartikel (refereegranskat)abstract
- Until now, there have been few assays to measure C-peptide and proinsulin in the rat. We used a well-established rat insulin ELISA and validated two novel ELISAs for rat C-peptide and rat/mouse proinsulin to examine secretion and content of insulin, proinsulin, and C-peptide from rat islets cultured for 72 h at different glucose concentrations in culture medium. To examine long-term effects in vitro rather than short-term effects of exposure to low, normal, and high glucose, the exposure time to the different glucose concentrations was set to 72 h. The measurement uncertainty of the values obtainable from the ELISAs was determined by calculation of the variation pattern from the intraassay variation generated by unknown samples, and repeatability was determined by analysis of controls. The precision study and the analysis of controls confirm that the validated ELISAs for rat C-peptide and proinsulin would be useful for further studies on the effects of preculture in different glucose concentrations. The higher the glucose concentration used during the 72-h culture period of rat islets, the higher insulin, C-peptide and proinsulin values were obtained in a subsequent short-term glucose-challenge experiment. The proportion of proinsulin to insulin secreted increased, as did islet content, with increasing glucose concentration during preculture. We also observed a nonequimolar, glucose-dependent secretion and content of rat insulin over rat C-peptide after culture at 11.1 and 28 mM glucose.
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| 23. |
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| 24. |
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| 25. |
- Chowdhury, Azazul Islam, et al.
(författare)
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Functional differences between aggregated and dispersed insulin-producing cells
- 2013
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 56:7, s. 1557-1568
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Tidskriftsartikel (refereegranskat)abstract
- Beta cells situated in the islet of Langerhans respond more vigorously to glucose than do dissociated beta cells. Mechanisms for this discrepancy were studied by comparing insulin-producing MIN6 cells aggregated into pseudoislets with MIN6 monolayer cells and mouse and human islets. MIN6 monolayers, pseudoislets and mouse and human islets were exposed to glucose, alpha-ketoisocaproic acid (KIC), pyruvate, KIC plus glutamine and the phosphatidylinositol 3-kinase (PI3K) inhibitors LY294002 or wortmannin. Insulin secretion (ELISA), cytoplasmic Ca2+ concentration ([Ca2+](c); microfluorometry), glucose oxidation (radiolabelling), the expression of genes involved in mitochondrial metabolism (PCR) and the phosphorylation of insulin receptor signalling proteins (western blotting) were measured. Insulin secretory responses to glucose, pyruvate, KIC and glutamine were higher in pseudoislets than monolayers and comparable to those of human islets. Glucose oxidation and genes for mitochondrial metabolism were upregulated in pseudoislets compared with single cells and monolayers, respectively. Phosphorylation at the inhibitory S636/639 site of IRS-1 was significantly higher in monolayers and dispersed human and mouse cells than pseudoislets and intact human and mouse islets. PI3K inhibition only slightly attenuated glucose-stimulated insulin secretion from monolayers, but substantially reduced that from pseudoislets and human and mouse islets without suppressing the glucose-induced [Ca2+](c) response. We propose that islet architecture is critical for proper beta cell mitochondrial metabolism and IRS-1 signalling, and that PI3K regulates insulin secretion at a step distal to the elevation of [Ca2+](c).
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| 26. |
- Digre, Andreas, 1987-, et al.
(författare)
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Overexpression of heparanase enhances T lymphocyte activities and intensifies the inflammatory response in a model of murine rheumatoid arthritis
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Heparanase is an endo-glucuronidase that degrades heparan sulfate chains. The enzyme is expressed at a low level in normal organs; however, elevated expression of heparanase has been detected in several inflammatory conditions, e.g. in the synovial joints of rheumatoid arthritis (RA) patients. Herein, we have applied the model of collagen-induced arthritis (CIA) to transgenic mice overexpressing human heparanase (Hpa-tg) along with wildtype (WT) mice. About 50 % of the induced animals developed clinical symptoms, i.e. swelling of joints, and there were no differences between the Hpa-tg and WT mice in the incidence of disease. However, Hpa-tg mice displayed an earlier response and developed more severe symptoms. Examination of cells from thymus, spleen and lymph nodes revealed increased innate and adaptive immune responses of the Hpa-tg mice, reflected by increased proportions of macrophages, antigen presenting cells and plasmacytoid dendritic cells as well as Helios-positive CD4+ and CD8+ T cells. Furthermore, splenic lymphocytes from Hpa-tg mice showed higher proliferation activity. Our results suggest that elevated expression of heparanase augmented both the innate and adaptive immune system and propagated inflammatory reactions in the murine RA model.
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| 27. |
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| 28. |
- Espes, Daniel, 1985-, et al.
(författare)
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Increased Interleukin-35 Levels in Patients With Type 1 Diabetes With Remaining C-Peptide
- 2017
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Ingår i: Diabetes Care. - : American Diabetes Association. - 0149-5992 .- 1935-5548. ; 40:8, s. 1090-1095
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE Many patients with long-standing type 1 diabetes have remaining functional β-cells. This study investigated immunological differences between patients with or without measurable remaining endogenous insulin production after ≥10 years duration of disease.RESEARCH DESIGN AND METHODS Patients (n = 113; ≥18 years of age) with type 1 diabetes and with disease duration of ≥10 years were recruited at Uppsala University Hospital. Residual β-cell function was determined with an ultrasensitive C-peptide ELISA. Circulating cytokines, including interleukin-35 (IL-35), were determined in plasma. Additional blood samples were collected from 14 of the identified C-peptide–positive patients and 12 of the C-peptide–negative patients, as well as from 15 healthy control subjects, and were used for immediate investigation of peripheral blood mononuclear cells.RESULTS The blood concentration of the cytokine IL-35 was markedly lower in C-peptide–negative patients, and this was associated with a simultaneous decrease in the proportion of IL-35+ regulatory T cells (Tregs), IL-35+ regulatory B cells, and IL-35–producing CD8+Foxp3+ cells. IL-35 has previously been shown to maintain the phenotype of Tregs, block the differentiation of T-helper 17 cells, and thereby dampen immune assaults to β-cells. We found that the proportions of IL-17a+ cells among the Tregs, CD4+ T cells, and CD8+ T cells were lower in the C-peptide–positive patients.CONCLUSIONS Patients with remaining endogenous β-cell function after >10 years duration of type 1 diabetes differ immunologically from other patients with long-standing type 1 diabetes. In particular, they have a much higher IL-35 production.
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| 29. |
- Henriksnäs, Johanna, et al.
(författare)
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Acute effects of Helicobacter pylori extracts on gastric mucosal blood flow in the mouse
- 2009
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Ingår i: World Journal of Gastroenterology. - : Baishideng Publishing Group Inc.. - 1007-9327 .- 2219-2840. ; 15:2, s. 219-225
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To investigate the mechanisms underlying the reduction in gastric blood flow induced by a luminal water extract of Helicobacter pylori (HPE).METHODS: The stomachs of isoflurane-anesthetized mice were exteriorized, and the mucosal surface exposed. Blood flow was measured with the laser-Doppler technique, and systemic arterial blood pressure monitored. C57BL/6 mice were exposed to water extract produced from H pylori strain 88-23. To investigate the role of a nerve- or iNOS-mediated pathway, we used intraluminal lidocaine and iNOS-/- mice. Blood flow response to the endogenous nitric oxide synthase inhibitor asymmetric dimethyl arginine (ADMA) was also assessed.RESULTS: In wild-type mice, HPE decreased mucosal blood flow by approximately 30%. This reduction was abolished in iNOS-deficient mice, and by pre-treatment with lidocaine. Luminally applied ADMA resulted in reduction in blood flow similar to that observed in wild-type mice exposed to HPE.CONCLUSION: A H pylori water extract reduces gastric mucosal blood flow acutely through iNOS- and nerve-mediated pathways.
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| 30. |
- Hägerkvist, Robert, et al.
(författare)
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Amelioration of diabetes by imatinib mesylate (Gleevec) : role of beta-cell NF-kappaB activation and anti-apoptotic preconditioning
- 2007
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Ingår i: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 21:2, s. 618-628
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Tidskriftsartikel (refereegranskat)abstract
- It was recently reported that tyrosine kinase inhibitor imatinib mesylate (Gleevec) improves Type 2 diabetes, possibly by decreasing insulin resistance. However, as both Type 2 and Type 1 diabetes are characterized by beta-cell dysfunction and death, we investigated whether imatinib counteracts diabetes by maintaining beta-cell function. We observed that imatinib counteracted diabetes in two animal models, the streptozotocin-injected mouse and the nonobese diabetes mouse, and that this was paralleled by a partial preservation of the beta-cell mass. In addition, imatinib decreased the death of human beta-cells in vitro when exposed to NO, cytokines, and streptozotocin. The imatinib effect was mimicked by siRNA-mediated knockdown of c-Abl mRNA. Imatinib enhanced beta-cell survival by promoting a state similar to ischemic preconditioning, as evidenced by NF-kappaB activation, increased NO and reactive oxygen species production, and depolarization of the inner mitochondrial membrane. Imatinib did not suppress islet cell death in the presence of an NF-kappaB inhibitor, suggesting that NF-kappaB activation is a necessary step in the antiapoptotic action of imatinib. We conclude that imatinib mediates beta-cell survival and that this could contribute to the beneficial effects observed in diabetes.
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| 31. |
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| 32. |
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| 33. |
- Hässler, Signe, et al.
(författare)
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Aire deficiency causes increased susceptibility to streptozotocin-induced murine type 1 diabetes
- 2008
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 67:6, s. 569-580
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Tidskriftsartikel (refereegranskat)abstract
- Aire-deficient mice are a model of the human monogenic disorder autoimmune polyendocrine syndrome type I (APS I) characterized by a progressive autoimmune destruction of multiple endocrine glands such as the adrenal cortex, the parathyroids and the beta-cells of the pancreas. The disease is caused by mutations in the autoimmune regulator (AIRE) gene, a putative transcription factor expressed in thymic medullary epithelial cells and in antigen-presenting cells of the myeloid lineage in peripheral lymphoid organs. As Aire(-/-) mice do not spontaneously develop endocrinopathies, we wanted to evaluate the autoimmune multiple low-dose streptozotocin (MLDSTZ) diabetes model in Aire(-/-) mice. Surprisingly, Aire heterozygote mice were most susceptible to MLDSTZ-induced diabetes, whereas Aire(-/-) mice displayed an intermediate sensitivity to diabetes. Furthermore, Aire(-/-) macrophages produced higher levels of TNF-alpha and lower levels of IL-10 following streptozotocin stimulation, and Aire(-/-) mice developed a higher frequency of islet cells autoantibodies as a sign of increased activation. However, the number of islet infiltrating F4/80(+) Aire(-/-) macrophages was significantly decreased which was attributed to an increased susceptibility to streptozotocin cytotoxicity of Aire(-/-) macrophages. In conclusion, Aire(-/-) macrophages display an increased activation after STZ stimuli, but suffer from increased susceptibility to STZ cytotoxicity. These results support an important function of Aire in the control of peripheral tolerance through myeloid antigen-presenting cells.
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- Karlsson, Maria G. E.
(författare)
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The Importance of Cell-Mediated Immunity for the Development of Type 1 Diabetes
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Type I (insulin-dependent) diabetes mellitus is an autoimmune disease characterised by infiltration of T-lymphocytes in the islets of Langerhans. In particular, activated Th1-like lymphocytes secreting IFN-γ are suggested to contribute to the inflammatory process and the destruction of ß-cells, whereas Th2-like cells producing IL-4 might even be protective. Environmental factors (diet, viruses, stress etc.) and autoantigens, e.g. Glutamic Acid Decarboxylase (GAD65) and insulin, are suggested to initiate the autoimmune process resulting in type I diabetes.Aim To estimate the immunological balance of Th1/Th2-like lymphocytes, spontaneously and after stimulation with antigens, in high-risk first degree relatives of type 1 diabetic children and in children with newly diagnosed type 1 diabetes.Materials and methods Peripheral blood mononuclear cells (PBMC) from healthy high-risk first-degree relatives (ICA ≥ 20) and newly diagnosed type 1 diabetic children were examined and compared with the response seen in PBMC from healthy controls matched for age and HLA-type (DR3 and/or DR4).Expression of IFN-γ and IL-4 mRNA was determined by RT-PCR or real-time RTPCR and IFN-γ and IL-4 by ELISPOT or ELISA, spontaneously and after stimulation with GAD65 , insulin, bovine serum albumin (BSA), the ABBOS-peptide and ß-lactoglobulin (ßLG). Cytokine expression and secretion was compared to the production of diabetes-associated autoantibodies and to the secretion of endogenous insulin.Results The epitope of GAD65, that mimics the Coxsackie B virus, caused increased IFN-γ mRNA expression in activated Th1-like lymphocytes from newly diagnosed diabetic children. This suggests that GAD65 might be involved in the development of type I diabetes. On the contrary, cow's milk proteins caused increased IFN-γ and IL- 4 mRNA expression in activated Th1- and Th2-like lymphocytes from both diabetic and healthy children. This does not support the hypothesis that cow's milk antigens are important for the development of type 1 diabetes.Overwhelming secretion of IFN-γ was observed in high-risk first-degree relatives of type 1 diabetic children. High-risk individuals still have the ability to change a Th1-like immune deviation into a more protective Th2-like response in the presence of GAD65 and insulin.Conclusions GAD65, but not cow's milk proteins, causes a Th1-like deviation in type 1 diabetic children. High-risk individuals are capable to deviate a Th1-like immune system into a more protective Th2-like response in the presence of autoantigens. These results can be useful in future therapeutic approaches.
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- Li, Xiujuan, et al.
(författare)
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Pro-tumoral immune cell alterations in wild type and Shb-deficient mice in response to 4T1 breast carcinomas
- 2018
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 9:27, s. 18720-18733
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Tidskriftsartikel (refereegranskat)abstract
- To assess mechanisms responsible for breast carcinoma metastasis, 4T1 breast carcinomas were grown orthotopically in wild type or Shb knockout mice. Tumor growth, metastasis, vascular characteristics and immune cell properties were analyzed. Absence of Shb did not affect tumor growth although it increased lung metastasis. Shb knockout mouse tumors showed decreased redness and less developed vascular plexa located at the periphery of the tumors. No difference in overall tumor vascular density, leakage or pericyte coverage was noted between the genotypes although the average vessel size was smaller in the knockout. Tumors induced an increase of CD11b+ cells in spleen, lymph node, thymus, bone marrow and blood. Numbers of Shb knockout CD11b/CD8+ cells were decreased in lymph nodes and bone marrow of tumor bearing mice. Mice with tumors had reduced numbers of CD4+ lymphocytes in blood/lymphoid organs, whereas in most of these locations the proportion of CD4+ cells co-expressing FoxP3 was increased, suggesting a relative increase in Treg cells. This finding was reinforced by increased blood interleukin-35 (IL-35) in wild type tumor bearing mice. Shb knockout blood showed in addition an increased proportion of IL-35 expressing Treg cells, supporting the notion that absence of Shb further promotes tumor evasion from immune cell recognition. This could explain the increased number of lung metastases observed under these conditions. In conclusion, 4T1 tumors alter immune cell responses that promote tumor expansion, metastasis and escape from T cell recognition in an Shb dependent manner.
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- Lindgren, Stefan, et al.
(författare)
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Medical education in Sweden
- 2011
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Ingår i: Medical teacher. - London : Update. - 0142-159X .- 1466-187X. ; 33:10, s. 798-803
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Tidskriftsartikel (refereegranskat)abstract
- Undergraduate medical education in Sweden has moved from nationally regulated, subject-based courses to programmes integrated either around organ systems or physiological and patho-physiological processes, or organised around basic medical science in conjunction with clinical specialities, with individual profiles at the seven medical schools. The national regulations are restricted to overall academic and professional outcomes. The 51/2 year long university undergraduate curriculum is followed by a mandatory 18 months internship, delivered by the County Councils. While quality control and accreditation for the university curriculum is provided by the Swedish National Agency for Higher Education, no such formal control exists for the internship; undergraduate medical education is therefore in conflict with EU directives from 2005. The Government is expected to move towards 6 years long university undergraduate programmes, leading to licence, which will facilitate international mobility of both Swedish and foreign medical students and doctors. Ongoing academic development of undergraduate education is strengthened by the Bologna process. It includes outcome (competence)-based curricula, university Masters level complying with international standards, progression of competence throughout the curriculum, student directed learning, active participation and roles in practical clinical education and a national assessment model to assure professional competence. In the near future, the dimensioning of Swedish undergraduate education is likely to be decided more by international demands and aspects of quality than by national demands for doctors.
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| 48. |
- Ludvigsen, Eva, et al.
(författare)
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Altered Expression of Somatostatin Receptors in Pancreatic Islets from NOD Mice Cultured at Different Glucose Concentrations In Vitro and in Islets Transplanted to Diabetic NOD Mice In Vivo
- 2011
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Ingår i: Experimental Diabetes Research. - : Hindawi Limited. - 1687-5214 .- 1687-5303. ; 2011, s. 623472-
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Tidskriftsartikel (refereegranskat)abstract
- Somatostatin acts via five receptors (sst1-5). We investigated if the changes in pancreatic islet sst expression in diabetic NOD mice compared to normoglycemic mice are a consequence of hyperglycemia or the ongoing immune reaction in the pancreas. Pancreatic islets were isolated from NOD mice precultured for 5 days and further cultured for 3 days at high or low glucose before examined. Islets were also isolated from NOD mice and transplanted to normal or diabetic mice in a number not sufficient to cure hyperglycemia. After three days, the transplants were removed and stained for sst1-5 and islet hormones. Overall, changes in sst islet cell expression were more common in islets cultured in high glucose concentration in vitro as compared to the islet transplantation in vivo to diabetic mice. The beta and PP cells exhibited more frequent changes in sst expression, while the alpha and delta cells were relatively unaffected by the high glucose condition. Our findings suggest that the glucose level may alter sst expressed in islets cells; however, immune mechanisms may counteract such changes in islet sst expression.
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