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- Ringström, Camilla, et al.
(författare)
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Apelin is a novel islet peptide.
- 2010
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Ingår i: Regulatory Peptides. - : Elsevier BV. - 1873-1686 .- 0167-0115. ; 162, s. 44-51
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Tidskriftsartikel (refereegranskat)abstract
- Apelin, a recently discovered peptide with wide tissue distribution, regulates feeding behavior, improves glucose utilization, and inhibits insulin secretion. We examined whether apelin is expressed in human islets, as well as in normal and type 2 diabetic (T2D) animal islets. Further, we studied islet apelin regulation and the effect of apelin on insulin secretion. Apelin expression and regulation was examined in human and animal specimens using immunocytochemistry, in situ hybridization, and real-time PCR. Insulin secretion was studied in INS-1 (832/13) clonal beta cells. APJ-receptor expression was studied using real-time PCR. In human and murine islets apelin was predominantly expressed in beta cells and alpha cells; a subpopulation of the PP cells in human islets also harbored apelin. In porcine and feline islets apelin was mainly expressed in beta cells. APJ-receptor expression was detected in INS-1 (832/13) cells, and in human and mouse islets. A high dose (1microM) of apelin-36 caused a moderate increase in glucose-stimulated insulin secretion (30%; p<0.001), while lower concentrations (10-100nM) of apelin robustly reduced insulin secretion by 50% (p<0.001). Apelin was upregulated in beta cells of T2D db/db mice (47% vs. controls; p<0.02) and GK-rats (74% vs. controls; p<0.002), but human islet apelin expression was unaffected by glucose. On the other hand, human islet apelin expression was diminished after culture in glucocorticoids (16% vs. controls; p<0.01). We conclude that apelin is a novel insulin-regulating islet peptide in humans and several laboratory animals. Islet apelin expression is negatively regulated by glucocorticoids, and upregulated in T2D animals. The presence of apelin receptors in islets suggests a role for apelin as a paracrine or autocrine messenger within the islets.
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- Strickertsson, Jesper A. B., et al.
(författare)
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Enterococcus faecalis Infection Causes Inflammation, Intracellular Oxphos-Independent ROS Production, and DNA Damage in Human Gastric Cancer Cells
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Achlorhydria caused by e.g. atrophic gastritis allows for bacterial overgrowth, which induces chronic inflammation and damage to the mucosal cells of infected individuals driving gastric malignancies and cancer. Enterococcus faecalis (E. faecalis) can colonize achlohydric stomachs and we therefore wanted to study the impact of E. faecalis infection on inflammatory response, reactive oxygen species (ROS) formation, mitochondrial respiration, and mitochondrial genetic stability in gastric mucosal cells. Methods: To separate the changes induced by bacteria from those of the inflammatory cells we established an in vitro E. faecalis infection model system using the gastric carcinoma cell line MKN74. Total ROS and superoxide was measured by fluorescence microscopy. Cellular oxygen consumption was characterized non-invasively using XF24 microplate based respirometry. Gene expression was examined by microarray, and response pathways were identified by Gene Set Analysis (GSA). Selected gene transcripts were verified by quantitative real-time polymerase chain reaction (qRT-PCR). Mitochondrial mutations were determined by sequencing. Results: Infection of MKN74 cells with E. faecalis induced intracellular ROS production through a pathway independent of oxidative phosphorylation (oxphos). Furthermore, E. faecalis infection induced mitochondrial DNA instability. Following infection, genes coding for inflammatory response proteins were transcriptionally up-regulated while DNA damage repair and cell cycle control genes were down-regulated. Cell growth slowed down when infected with viable E. faecalis and responded in a dose dependent manner to E. faecalis lysate. Conclusions: Infection by E. faecalis induced an oxphos-independent intracellular ROS response and damaged the mitochondrial genome in gastric cell culture. Finally the bacteria induced an NF-kappa B inflammatory response as well as impaired DNA damage response and cell cycle control gene expression.
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- Strickertsson, Jesper A. B., et al.
(författare)
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Interferon-gamma inhibits ghrelin expression and secretion via a somatostatin-mediated mechanism
- 2011
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Ingår i: World Journal of Gastroenterology. - 1007-9327. ; 17:26, s. 3117-3125
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To investigate if and how the proinflammatory cytokine interferon gamma (IFN gamma) affects ghrelin expression in mice. METHODS: The plasma concentration of ghrelin, and gastric ghrelin and somatostatin expression, were examined in wild-type mice and mice infected with Helicobacter pylori (H. pylon). Furthermore, ghrelin expression was examined in two achlorhydric mouse models with varying degrees of gastritis due to bacterial overgrowth. To study the effect of IFN gamma alone, mice were given a subcutaneous infusion of IFN gamma for 7 d. Finally, the influence of IFN gamma, and somatostatin on the ghrelin promoter was characterized. RESULTS: H. pylori infection was associated with a 50% reduction in ghrelin expression and plasma concentration. Suppression of ghrelin expression was inversely correlated with gastric inflammation in achlorhdyric mouse models. Subcutaneous infusion of IFN gamma suppressed fundic ghrelin mRNA expression and plasma ghrelin concentrations. Finally, we showed that the ghrelin promoter operates under the control of somatostatin but not under that of IFN gamma. CONCLUSION: Gastric infection and inflammation is associated with increased IFN gamma expression and reduced ghrelin expression. IFN gamma does not directly control ghrelin expression but inhibits it indirectly via somatostatin. (C) 2011 Baishideng. All rights reserved.
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- Åstrand, Ramona, et al.
(författare)
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Comparison between capillary, venous and arterial levels of protein S100B in patients with severe brain pathology
- 2012
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 50:6, s. 1055-1061
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Tidskriftsartikel (refereegranskat)abstract
- Background: Protein S100B is soon in clinical use as a sensitive marker after mild traumatic head injury in adults. Initial studies of S100B in pediatric head injury have shown promising results. Venous sampling can be challenging in children and capillary samples are often a preferred option. The aim of the study was to investigate the relation between capillary, venous and arterial measurements of protein S100B, primarily by determining whether capillary S100B differ from venous and if capillary S100B can predict venous S100B levels, and secondarily, if arterial S100B samples can substitute venous samples in severely brain-injured patients. Methods: Venous, arterial and capillary blood samples for S100B were collected simultaneously once a day for a maximum of 6 days. Patients were >= 18 years old and admitted to neurointensive care due to severe brain pathology. Results: Capillary S100B samples were on average 0.08 mu g/L higher than venous S100B samples. Prediction of venous concentration from capillary samples yielded a prediction error of 0.07 mu g/L. The mean difference between venous and arterial samples was 0.01 mu g/L. The mean prediction error was 0.03 mu g/L. Conclusions: Capillary and venous serum S100B are not interchangeable, and should be considered as two separate, although related, variables. Arterial measurements of S100B can successfully predict the corresponding venous concentration.
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