| 1. |
- Sotak, Matus, et al.
(författare)
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Intestinal sodium/glucose cotransporter 3 expression is epithelial and downregulated in obesity.
- 2021
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Ingår i: Life sciences. - : Elsevier BV. - 1879-0631 .- 0024-3205. ; 267
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Tidskriftsartikel (refereegranskat)abstract
- We aimed to determine whether the sodium/glucose cotransporter family member SGLT3, a proposed glucose sensor, is expressed in the intestine and/or kidney, and if its expression is altered in mouse models of obesity and in humans before and after weight-loss surgery.We used in-situ hybridization and quantitative PCR to determine whether the Sglt3 isoforms 3a and 3b were expressed in the intestine and kidney of C57, leptin-deficient ob/ob, and diabetic BTBR ob/ob mice. Western blotting and immunohistochemistry were also used to assess SGLT3 protein levels in jejunal biopsies from obese patients before and after weight-loss Roux-en-Y gastric bypass surgery (RYGB), and in lean healthy controls.Sglt3a/3b mRNA was detected in the small intestine (duodenum, jejunum and ileum), but not in the large intestine or kidneys of mice. Both isoforms were detected in epithelial cells (confirmed using intestinal organoids). Expression of Sglt3a/3b mRNA in duodenum and jejunum was significantly lower in ob/ob and BTBR ob/ob mice than in normal-weight littermates. Jejunal SGLT3 protein levels in aged obese patients before Roux-en-Y gastric bypass (RYGB) were lower than in lean individuals, but substantially upregulated 6months post-RYGB.Our study shows that Sglt3a/3b is expressed primarily in epithelial cells of the small intestine in mice. Furthermore, we observed an association between intestinal mRNA Sglt3a/3b expression and obesity in mice, and between jejunal SGLT3 protein levels and obesity in humans. Further studies are required to determine the possible role of SGLT3 in obesity.
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| 2. |
- Wallenius, Ville, 1970, et al.
(författare)
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Glycemic Control and Metabolic Adaptation in Response to High-Fat versus High-Carbohydrate Diets-Data from a Randomized Cross-Over Study in Healthy Subjects.
- 2021
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Ingår i: Nutrients. - : MDPI AG. - 2072-6643. ; 13:10
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Tidskriftsartikel (refereegranskat)abstract
- Granular study of metabolic responses to alterations in the ratio of dietary macro-nutrients can enhance our understanding of how dietary modifications influence patients with impaired glycemic control. In order to study the effect of diets enriched in fat or carbohydrates, fifteen healthy, normal-weight volunteers received, in a cross-over design, and in a randomized unblinded order, two weeks of an iso-caloric high-fat diet (HFD: 60E% from fat) and a high-carbohydrate diet (HCD: 60E% from carbohydrates). A mixed meal test (MMT) was performed at the end of each dietary period to examine glucose clearance kinetics and insulin and incretin hormone levels, as well as plasma metabolomic profiles. The MMT induced almost identical glycemia and insulinemia following the HFD or HCD. GLP-1 levels were higher after the HFD vs. HCD, whereas GIP did not differ. The HFD, compared to the HCD, increased the levels of several metabolomic markers of risk for the development of insulin resistance, e.g., branched-chain amino acid (valine and leucine), creatine and α-hydroxybutyric acid levels. In normal-weight, healthy volunteers, two weeks of the HFD vs. HCD showed similar profiles of meal-induced glycemia and insulinemia. Despite this, the HFD showed a metabolomic pattern implying a risk for a metabolic shift towards impaired insulin sensitivity in the long run.
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| 3. |
- Bratlie, Svein-Olav, et al.
(författare)
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Proteomic Approach to the Potential Role of Angiotensin II in Barrett Dysplasia
- 2019
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Ingår i: Proteomics - Clinical Applications. - : Wiley. - 1862-8346 .- 1862-8354. ; 13:4
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aim: Dysplasia in Barrett's esophagus (BE) is regarded as a preneoplastic lesion. The renin–angiotensin system (RAS), known for its role in electrolyte homeostasis and hemodynamics, has also been shown to have tissue-based features linked to proliferation, inflammation, and cancer. RAS is associated with BE dysplasia. The aim of this study is to investigate possible effects of the RAS in BE dysplasia by using RAS-interfering pharmaceutical agents and by assessment of global protein expression in esophageal mucosal biopsies. Methods: Endoscopic biopsies are taken from 18 BE in patients with low-grade dysplasia before and after 3 weeks of treatment with either angiotensin-converting enzyme inhibitors (enalapril 5 mg; n = 6) or angiotensin II receptor type 1 blockers (candesartan 8 mg; n = 6), or no treatment (n = 6). A global proteomics analysis by 2D gel electrophoresis and mass spectrometry (MS) is then performed to identify proteins that are regulated after interference with RAS. Results: Three proteins are identified to show significant modulation of expression 60 kDa heat shock protein (downregulated), protein disulfide isomerase A3 (downregulated), and inorganic pyrophosphatase (upregulated). Conclusion: Three proteins with no previously known links to esophageal RAS, but with possible relevance for the development of esophageal adenocarcinoma (EAC) are detected. Altered expression by interference with the RAS suggests an involvement of angiotensin II in the development of EAC in BE. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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| 4. |
- Casselbrant, Anna, 1970, et al.
(författare)
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Angiotensin II exerts dual actions on sodium-glucose transporter 1-mediated transport in the human jejunal mucosa
- 2015
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 50:9, s. 1068-1075
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. Intestinal glucose absorption is mainly mediated via the sodium-glucose transporter 1 (SGLT1) at the apex of the enterocytes, whereas the glucose transporter 2 (GLUT2) provides a basolateral exit. It has been shown in rats that Angiotensin II (AngII), the principal mediator of renin-angiotensin system (RAS), inhibits jejunal SGLT1-mediated glucose absorption. The aim of the present study was to investigate if a similar mechanism exists also in the human jejunal mucosa. Material and methods. Enteroscopy with mucosal biopsy sampling was performed in 28 healthy volunteers. Functional assessments were performed in Ussing chambers using a pharmacological approach. Western blotting and immunohistochemistry were used to assess the presence of the AngII type 1 (AT1R) and type 2 receptor (AT2R), as well as the glucose transporters SGLT1 and GLUT2. Results. Exposure of the mucosa to 10 mM glucose elicited a »50% increase in the epithelium-generated current (Iep). This glucose-induced electrogenic response was sensitive to the competitive SGLT1 inhibitor phlorizin, but not to AngII when given alone. AngII combined with the AT2R blocker PD123319 markedly inhibited the response. AngII in combination with the AT1R antagonist losartan tended to increase the electrogenic response, whereas direct activation of AT2R using the agonist C21 significantly enhanced the mucosal response to glucose. The AT1R and AT2R as well as SGLT1 and GLUT2 were detected inside the human enterocytes. Conclusions. The pharmacological analysis indicated that activation of AT1R inhibits, whereas activation of AT2R enhances SGLT1-mediated glucose transport in the human jejunal mucosa.
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| 5. |
- Casselbrant, Anna, 1970, et al.
(författare)
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Expression of tight-junction proteins in human proximal small intestinal mucosa before and after Roux-en-Y gastric bypass surgery
- 2015
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Ingår i: Surgery for Obesity and Related Diseases. - : Elsevier BV. - 1550-7289. ; 11:1, s. 45-53
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Tidskriftsartikel (refereegranskat)abstract
- Background Increased permeability and uptake of proinflammatory bacterial endotoxins from gut microbiota has been suggested as a mechanism for obesity-associated chronic inflammation that causes obesity-associated insulin resistance. We hypothesized that intestinal barrier function may be restored after Roux-en-Y gastric bypass (RYGB) surgery and thereby contribute to decreased inflammation. The objective of this study was to investigate levels of the permeability-regulating tight-junction proteins in human small intestinal mucosa before and after RYGB surgery. Methods Paired intraindividual jejunal mucosa samples were retrieved at the time of surgery and 6 to 8 months after surgery. Mucosal cell surface area was calculated by histomorphometry. Mucosal samples were analyzed by proteomics to find patterns of protein regulations. Based on these findings further analyses were performed by Western blotting. Ussing chambers were used to analyze permeability in the retrieved mucosal samples. Results Mucosal surface area was significantly decreased after surgery. Global protein expression analysis showed a significant increase in the cytokeratin-8 (Ck8), which was confirmed by Western blotting. Further analyses showed a significant increase in claudin-3 and -4 expression after surgery, whereas occludin and zonula occludens-1 levels were decreased. Expressions of claudin-1, -2, -5 and vinculin were unchanged. Ussing chamber experiments revealed a linear correlation between the epithelial electrical resistance and claudin-3 protein expression. Conclusion Several alterations were found in the rerouted small intestine after surgery, indicating a decreased jejunal mucosal surface area and decreased paracellular permeability. These changes could contribute to decreased uptake of luminal microbiota-derived inflammatory mediators such as endotoxins after RYGB.
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| 6. |
- Casselbrant, Anna, 1970, et al.
(författare)
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Glycocholic acid and butyrate synergistically increase vitamin D-induced calcium uptake in Caco-2 intestinal epithelial cell monolayers
- 2020
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Ingår i: Bone Reports. - : Elsevier BV. - 2352-1872. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background: Roux-en-Y gastric bypass (RYGB) substantially decreases intestinal calcium absorption and may eventually lead to bone resorption. This is likely a consequence of bile diversion from the alimentary limb, as the presence of bile seems necessary for vitamin D-mediated calcium uptake. We recently suggested that the mediating mechanism may be a down-regulation of the vitamin D co-activator heat-shock protein (Hsp)90β. Recent evidence suggests that vitamin D may have effects on both active and passive calcium absorption. Aim: To identify mechanisms in vitro that may be responsible for the decreased calcium absorption after RYGB. We hypothesized that bile, alone or in concert with nutritional compounds, could be of importance. Material & methods: Caco-2 cells were grown confluent on semi-permeable membranes in a double-chamber setup to mimic small intestinal mucosa. The effect of bile acids chenodeoxycholic, lithocholic, glycocholic and taurocholic acid, with and without the addition of the fatty-acid butyrate, were tested for their effects on Hsp90β expression and active and passive calcium-flux monitored using radioactive 45Ca. Results: We initially found that whole human bile, but only together with the fatty acid butyrate, potently induced Hsp90β expression. In line with this, a single bile acid, e.g. glycocholic acid (GCA), in combination with butyrate, increased Hsp90β expression (40 ± 13% vs. GCA, butyrate or vehicle alone; p < 0,001; n = 14–25). Further, this combination together with vitamin D increased the passive gradient-driven flux of calcium, compared to stimulation with vitamin D alone or in combination with either GCA or butyrate (880 ± 217% vs. vitamin D and GCA or butyrate, or vitamin D only; p = 0,01–0.006; n = 5–11). Surprisingly, this combination had no effect on active calcium transport in the absence of calcium gradient. Conclusion: The combination of GCA and butyrate increased gradient-driven calcium uptake up to 9-fold in Caco-2 intestinal epithelial cells, but had no effect on active calcium absorption. This effect was mediated via the vitamin D receptor co-activator Hsp90β. © 2020 The Authors
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| 7. |
- Casselbrant, Anna, 1970, et al.
(författare)
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Morphological Adaptation in the Jejunal Mucosa after Iso-Caloric High-Fat versus High-Carbohydrate Diets in Healthy Volunteers: Data from a Randomized Crossover Study
- 2022
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Ingår i: Nutrients. - : MDPI AG. - 2072-6643. ; 14:19
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: The conditions for jejunal glucose absorption in healthy subjects have not been thoroughly studied. In this study we investigated differences in the jejunal villi enlargement factor, as well as ultrastructural aspects of the surface enterocytes and mitochondria, comparing 2 weeks of high-carbohydrate (HCD) versus high-fat diets (HFD). We also measured the ketogenesis rate-limiting enzyme 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS2) in relation to jejunal mitochondria. Methods: A single-centre, randomized, unblinded crossover study in 15 healthy volunteers ingesting strictly controlled equicaloric diets (either HCD or HFD), with 60% energy from the respective source. An enteroscopy was carried out after 2 weeks of each diet and jejunal mucosal biopsies were acquired. Conventional histology, immunofluorescent staining, transmission electron microscopy and confocal microscopy were used. Results: The villi did not demonstrate any change in the epithelial enlargement factor. Despite an increased mitosis, there were no changes in apoptotic indices. However, the ultrastructural analysis demonstrated a significant increase in the enlargement factor at the bases of the villi. The mitochondria demonstrated increased amounts of cristae after the HFD. The confocal microscopy revealed increased HMGCS2 per mitochondrial marker at the top of the villi after the HFD compared to the HCD. Conclusion: There is a morphometric adaption in the jejunal mucosa following the 2-week diets, not only on a histological level, but rather on the ultrastructural level. This study supports the notion that mitochondrial HMGCS2 is regulated by the fat content of the diet and is involved in the expression of monosaccharide transporters.
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| 8. |
- Cervin, Jakob, et al.
(författare)
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GM1 ganglioside-independent intoxication by Cholera toxin
- 2018
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Ingår i: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 14:2
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Tidskriftsartikel (refereegranskat)abstract
- Cholera toxin (CT) enters and intoxicates host cells after binding cell surface receptors via its B subunit (CTB). We have recently shown that in addition to the previously described binding partner ganglioside GM1, CTB binds to fucosylated proteins. Using flow cytometric analysis of primary human jejunal epithelial cells and granulocytes, we now show that CTB binding correlates with expression of the fucosylated Lewis X (LeX) glycan. This binding is competitively blocked by fucosylated oligosaccharides and fucose-binding lectins. CTB binds the LeX glycan in vitro when this moiety is linked to proteins but not to ceramides, and this binding can be blocked by mAb to LeX. Inhibition of glycosphingolipid synthesis or sialylation in GM1-deficient C6 rat glioma cells results in sensitization to CT-mediated intoxication. Finally, CT gavage produces an intact diarrheal response in knockout mice lacking GM1 even after additional reduction of glycosphingolipids. Hence our results show that CT can induce toxicity in the absence of GM1 and support a role for host glycoproteins in CT intoxication. These findings open up new avenues for therapies to block CT action and for design of detoxified enterotoxin-based adjuvants.
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| 9. |
- Elebring, Erik, 1990, et al.
(författare)
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A Fatty Diet Induces a Jejunal Ketogenesis Which Inhibits Local SGLT1-Based Glucose Transport via an Acetylation Mechanism-Results from a Randomized Cross-Over Study between Iso-Caloric High-Fat versus High-Carbohydrate Diets in Healthy Volunteers
- 2022
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Ingår i: Nutrients. - : MDPI AG. - 2072-6643. ; 14:9
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Insights into the nature of gut adaptation after different diets enhance the understanding of how food modifications can be used to treat type 2 diabetes and obesity. The aim was to understand how diets, enriched in fat or carbohydrates, affect glucose absorption in the human healthy jejunum, and what mechanisms are involved. Methods: Fifteen healthy subjects received, in randomised order and a crossover study design, two weeks of iso-caloric high-fat diet (HFD) and high-carbohydrate diet (HCD). Following each dietary period, jejunal mucosa samples were retrieved and assessed for protein expression using immunofluorescence and western blotting. Functional characterisation of epithelial glucose transport was assessed ex vivo using Ussing chambers. Regulation of SGLT1 through histone acetylation was studied in vitro in Caco-2 and human jejunal enteroid monolayer cultures. Results: HFD, compared to HCD, decreased jejunal Ussing chamber epithelial glucose transport and the expression of apical transporters for glucose (SGLT1) and fructose (GLUT5), while expression of the basolateral glucose transporter GLUT2 was increased. HFD also increased protein expression of the ketogenesis rate-limiting enzyme mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS2) and decreased the acetylation of histone 3 at lysine 9 (H3K9ac). Studies in Caco-2 and human jejunal enteroid monolayer cultures indicated a ketogenesis-induced activation of sirtuins, in turn decreasing SGLT1 expression. Conclusion: Jejunal glucose absorption is decreased by a fat-enriched diet, via a ketogenesis-induced alteration of histone acetylation responsible for the silencing of SGLT1 transcription. The work relates to a secondary outcome in ClinicalTrials.gov (NCT02088853).
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| 10. |
- Elebring, Erik, 1990, et al.
(författare)
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βHB inhibits glucose-induced GLP-1 secretion in GLUTag and human jejunal enteroids
- 2023
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Ingår i: Journal of molecular endocrinology. - 1479-6813. ; 70:4
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Tidskriftsartikel (refereegranskat)abstract
- Ingestion of nutrients stimulates incretin secretion from enteroendocrine cells (EECs) of the epithelial layer of the gut. Glucagon-like peptide-1 (GLP-1) is one of these incretins that stimulate postprandial insulin release and signal satiety to the brain. Understanding the regulation of incretin secretion might open up new therapeutic options for obesity and type-2 diabetes mellitus. To investigate the inhibitory effect of the ketone body β-hydroxybutyrate (βHB) on glucose-induced GLP-1 secretion from EECs, in vitro cultures of murine GLUTag cells and differentiated human jejunal enteroid monolayers were stimulated with glucose to induce GLP-1 secretion. The effect of βHB on GLP-1 secretion was studied using ELISA and ECLIA methods. GLUTag cells stimulated with glucose and βHB were analysed using global proteomics focusing on cellular signalling pathways and the results were verified by Western blot. Results demonstrated βHB had a significant inhibitory effect on glucose-induced GLP-1 secretion at a dose of 100 mM in GLUTag cells. In differentiated human jejunal enteroid monolayers, glucose-induced secretion of GLP-1 was inhibited at a much lower dose of 10 mM βHB. The addition of βHB to GLUTag cells resulted in decreased phosphorylation of kinase AKT and transcription factor STAT3 and also influenced the expressions of signalling molecule IRS-2, kinase DGKε and receptor FFAR3. In conclusion, βHB displays an inhibitory effect on glucose-induced GLP-1 secretion in vitro in GLUTag cells and in differentiated human jejunal enteroid monolayers. This effect may be mediated through multiple downstream mediators of G-protein coupled receptor activation, such as PI3K signalling.
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| 11. |
- Elias, Erik, 1979, et al.
(författare)
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Bone mineral density and expression of vitamin D receptor-dependent calcium uptake mechanisms in the proximal small intestine after bariatric surgery
- 2014
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Ingår i: British Journal of Surgery. - : Oxford University Press (OUP). - 0007-1323 .- 1365-2168. ; 101:12, s. 1566-1575
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Tidskriftsartikel (refereegranskat)abstract
- Background Roux-en-Y gastric bypass may lead to impaired calcium uptake. Therefore, operation-specific effects of gastric bypass and vertical banded gastroplasty on bone mineral density (BMD) were examined in a randomized clinical trial. Bone resorption markers and mechanisms of decreased calcium uptake after gastric bypass were investigated using blood and endoscopic samples from two additional patient cohorts. Methods Total BMD and non-weight-bearing skull BMD were measured by dual-energy X-ray absorptiometry at baseline, and 1 and 6years after gastric bypass or vertical banded gastroplasty in patients who were not receiving calcium supplements. Bone resorption markers in serum and calcium uptake mechanisms in jejunal mucosa biopsies were analysed after gastric bypass by proteomics including radioimmunoassay, gel electrophoresis and mass spectrometry. Results One year after surgery, weight loss was similar after gastric bypass and vertical banded gastroplasty. There was a moderate decrease in skull BMD after gastric bypass, but not after vertical banded gastroplasty (P<0·001). Between 1 and 6years after gastric bypass, skull BMD and total BMD continued to decrease (P=0·001). C-terminal telopeptide levels in serum had increased twofold by 18months after gastric bypass. Proteomic analysis of the jejunal mucosa revealed decreased levels of heat-shock protein 90β, a co-activator of the vitamin D receptor, after gastric bypass. Despite increased vitamin D receptor levels, expression of the vitamin D receptor-regulated calcium transporter protein TRPV6 decreased. Conclusion BMD decreases independently of weight after gastric bypass. Bone loss might be attributed to impaired calcium absorption caused by decreased activation of vitamin D-dependent calcium absorption mechanisms mediated by heat-shock protein 90β and TRPV6.
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| 12. |
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| 13. |
- Wallenius, Ville, 1970, et al.
(författare)
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Suppression of enteroendocrine cell glucagon-like peptide (GLP)-1 release by fat-induced small intestinal ketogenesis: a mechanism targeted by Roux-en-Y gastric bypass surgery but not by preoperative very-low-calorie diet.
- 2020
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Ingår i: Gut. - : BMJ. - 1468-3288 .- 0017-5749. ; 69:8, s. 1423-1431
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Tidskriftsartikel (refereegranskat)abstract
- Food intake normally stimulates release of satiety and insulin-stimulating intestinal hormones, such as glucagon-like peptide (GLP)-1. This response is blunted in obese insulin resistant subjects, but is rapidly restored following Roux-en-Y gastric bypass (RYGB) surgery. We hypothesised this to be a result of the metabolic changes taking place in the small intestinal mucosa following the anatomical rearrangement after RYGB surgery, and aimed at identifying such mechanisms.Jejunal mucosa biopsies from patients undergoing RYGB surgery were retrieved before and after very-low calorie diet, at time of surgery and 6 months postoperatively. Samples were analysed by global protein expression analysis and Western blotting. Biological functionality of these findings was explored in mice and enteroendocrine cells (EECs) primary mouse jejunal cell cultures.The most prominent change found after RYGB was decreased jejunal expression of the rate-limiting ketogenic enzyme mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (mHMGCS), corroborated by decreased ketone body levels. In mice, prolonged high-fat feeding induced the expression of mHMGCS and functional ketogenesis in jejunum. The effect of ketone bodies on gut peptide secretion in EECs showed a ∼40% inhibition of GLP-1 release compared with baseline.Intestinal ketogenesis is induced by high-fat diet and inhibited by RYGB surgery. In cell culture, ketone bodies inhibited GLP-1 release from EECs. Thus, we suggest that this may be a mechanism by which RYGB can remove the inhibitory effect of ketone bodies on EECs, thereby restituting the responsiveness of EECs resulting in increased meal-stimulated levels of GLP-1 after surgery.
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| 14. |
- Andreasson, Emma, et al.
(författare)
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Expression of reactive oxygen species in reflux disease
- 2011
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Ingår i: Gastrointestinal Endoscopy. - Rijeka, Croatia : InTech. - 9789533073859 ; , s. 79-90
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Background: High levels of nitric oxide (NO) are formed when nitrite in swallowed saliva meets acidic refluxates in the distal esophagus. In inflamed tissue with production of reactive-oxygen-species (ROS) it is reasonable to assume that luminal NO will react with particularly superoxide and form the extremely labile oxidising compound peroxynitrite. Such oxidative species have potential roles in all steps of carcinogenesis. The aim of the present study is to elucidate the presence of radical producing enzymes, and elucidate the histological changes and number of inflammatory cells in human esophageal mucosa. Material and Methods: Biopsies from healthy volunteers and patients with erosive reflux disease (ERD) were analysed for myeloperoxidase (MPO), inducible nitric oxide synthase (iNOS) and NADPH oxidase, well as the expression of inflammatory markers IL1β and IL6 by western blot technique. Expression of nitrotyrosine was used as an indicator of peroxynitrite activity, thus mirroring the foregoing radical formation. A histological evaluation of inflammation and a morphometric investigation were performed on mucosal specimens. Results: Expression of MPO and nitrotyrosine formation was up regulated in the ERD-patients compared healthy controls. No significant differences in expression of iNOS, NADPH oxidase, IL1β or IL6 were detected. No signs of active inflammation, defined as presence of inflammatory cells were observed, whereas histological signs of erosive mucosal disease were confirmed in the esophageal mucosa. Conclusion: There were clear signs of increased radical forming capacity in the epithelium despite absence of histological inflammation, in association to ERD. During acidified refluxes, epithelial ROS production in combination with luminal NO formation, may constitute aggravated factors in the carcinogenic process.
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| 15. |
- Bagge, Jasmine, et al.
(författare)
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Mucosal Recovery after Intestinal Transplantation in the Rat: A Sequential Histological and Molecular Assessment
- 2023
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Ingår i: European Surgical Research. - : S. Karger AG. - 0014-312X .- 1421-9921. ; 64:2, s. 201-210
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Intestinal cold ischemia and subsequent reperfusion during transplantation result in various degrees of mucosal injury ranging from mild edema to extensive mucosal loss. Mucosal barrier impairment favours bacterial translocation and fluid loss and raises nutritional challenges. The injured intestine also releases proinflammatory mediators and upregulates various epitopes towards an inflammatory phenotype. We studied the process of mucosal injury and repair during the early period after intestinal transplantation from a histological and molecular standpoint.Materials and Methods Adult Sprague Dawley rats were used as donors and recipients. Donor intestines were perfused and stored in saline for 3 hours, then transplanted heterotopically using microvascular anastomoses. Intestinal graft segments were obtained after 20 minutes, 6 hours, 12 hours, and 24 hours after reperfusion. Histology studies (goblet cell count, morphometry), immunofluorescence and western blot for several tight junction proteins, apoptosis and inflammation related proteins were performed.Results Cold storage led to extensive epithelial detachment, whereas reperfusion resulted in extensive villus loss (about 60 % of the initial length) and goblet cell numbers were drastically reduced. Over the first 24 hours, gradual morphologic and molecular recovery was noted, although several molecular alterations persisted (increased apoptosis and inflammation, altered expression of several tight junctions).Conclusions The current data suggest that a near-complete morphologic recovery from a moderate mucosal injury occurs within the first 24 hours after intestinal transplantation. However, several molecular alterations persist and need to be considered when designing intestinal transplant experiments and choosing sampling and endpoints.
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| 16. |
- Björkman, Eleonora, 1981, et al.
(författare)
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Angiotensin IV and the human esophageal mucosa: An exploratory study in healthy subjects and gastroesophageal reflux disease patients.
- 2015
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Ingår i: Journal of the renin-angiotensin-aldosterone system : JRAAS. - : Hindawi Limited. - 1752-8976 .- 1470-3203. ; 16:3, s. 570-577
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Tidskriftsartikel (refereegranskat)abstract
- The human esophageal mucosa expresses various components of the renin-angiotensin system (RAS), e.g. the main effector peptide angiotensin II (AngII). The aim of this study was to investigate the esophageal presence of angiotensin III (AngIII) and angiotensin IV (AngIV) forming enzymes and the AngIV receptor (AT4R). The aim was also to study the actions of AngIV and to look for aberrations in patients with gastroesophageal reflux disease (GERD).
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| 17. |
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| 18. |
- Björkman, Eleonora, 1981, et al.
(författare)
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In vitro assessment of epithelial electrical resistance in human esophageal and jejunal mucosae and in Caco-2 cell layers.
- 2012
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Ingår i: Scandinavian journal of gastroenterology. - : Informa UK Limited. - 1502-7708 .- 0036-5521. ; 47:11, s. 1321-1333
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Objective. There is a need for a technique allowing studies of human mucosal specimens collected during different clinical conditions. This study elucidates if square wave pulse analysis discriminates between epithelial and transmural electrical resistance and if there is an association with transepithelial permeability of molecular probes. Methods. Mucosae from esophagus (surgical resections: n = 14; endoscopic biopsies: n = 15) and jejunum (n = 12) and Caco-2 cell monolayers were investigated in Ussing chambers. Transmural and epithelial electrical resistance were recorded by the use of standardized current pulses. Permeability was assessed using two fluorescein-labeled probes (weight 376 and 4000 Da). Results. Baseline epithelial electrical resistance was higher in esophageal mucosa (∼280 Ω*cm(2)), than in jejunal (∼10 Ω*cm(2)) and Caco-2 cells (∼140 Ω*cm(2)). The subepithelial contribution to the transmural resistance was higher in jejunal preparations (+88%) and Caco-2 cells (+75%), than in esophageal (+30%). During hypoxia the subepithelial resistance was unchanged, whereas the epithelial resistance decreased significantly in jejunal mucosa and Caco-2 cells. These findings coincided with increased transepithelial probe permeability and signs of disturbed morphology. Esophageal epithelia were resistant to hypoxia. However, exposure to deoxycholic acid and trypsin abolished the esophageal epithelial resistance and increased probe permeability. Endoscopic esophageal biopsies from patients with erosive reflux disease exhibited significantly lower epithelial resistance and higher current than healthy subjects. Conclusion. Square wave pulse analysis in Ussing chambers is suitable for assessment of epithelial electrical resistance that can reflect transepithelial permeability of molecular probes with known size. Moreover, the technique discriminated between healthy and reflux-diseased esophageal mucosal biopsies.
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| 19. |
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| 20. |
- Bove, Mogens, 1949, et al.
(författare)
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Acid challenge to the esophageal mucosa: effects on local nitric oxide formation and its relation to epithelial functions
- 2005
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Ingår i: Dig Dis Sci. - : Springer Science and Business Media LLC. - 0163-2116 .- 1573-2568. ; 50:4, s. 640-8
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Tidskriftsartikel (refereegranskat)abstract
- To evaluate the effect of esophageal acid exposure on epithelial function, transmucosal potential, histopathological markers of acute tissue damage, and local nitric oxide production were examined in healthy volunteers treated with proton pump inhibitors (group I), patients with treated reflux disease (group II), and patients with untreated erosive reflux disease (group III). The participants were randomized to esophageal perfusion with either saline or HCl. Denominators of acute acid exposure were balloon cells in superficial layers and superficial densification. The nitric oxide concentrations in groups I to III increased from < 1, 10.0+/-10.0, and 20.6+/-19.9 ppb, respectively, to 300+/-80, 1360+/-1080, and 920+/-700 ppb after HCl infusion (P < 0.001). Inducible nitric oxide synthase was consistently expressed in the epithelium. Blood flow was lower among reflux patients but did not correlate with acid exposure or nitric oxide. Nitric oxide is formed following acid perfusion and predominantly in gastroesophageal reflux disease.
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| 21. |
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| 22. |
- Bratlie, Svein-Olav, et al.
(författare)
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Support for involvement of the renin-angiotensin system in dysplastic Barrett's esophagus
- 2017
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 52:3, s. 338-343
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Tidskriftsartikel (refereegranskat)abstract
- Background and aim: Patients with dysplasia in Barrett's esophagus (BE) have a considerable risk of developing esophageal adenocarcinoma (EAC). The mucosal expression of the pro-inflammatory angiotensin II receptor type 1 (AT1R) is elevated in these patients, suggesting a role in carcinogenesis. The purpose of this study was to determine whether interference with the renin-angiotensin system (RAS) would influence downstream markers of carcinogenesis.Methods: Endoscopic mucosal biopsies from BE patients with low-grade dysplasia (LGD) were sampled before and after a three-week period of RAS-interfering treatment. Thirty patients were randomly allocated to enalapril (ACE inhibitor, 5mg od), candesartan (AT1R antagonist, 8mg od), or no drug. The expression of 12 proteins known to be associated with RAS and carcinogenesis was assessed using western blot.Results: We found altered expression of several proteins after enalapril treatment (decreased: NFB, p=.043; NLRP3, p=.050; AMACR, p=.017; and caspase 3, p=.025; increased: p53, p=.050). Candesartan treatment was associated with increased iNOS expression (p=.033). No significant changes were seen in the no-drug group.Conclusion: Interference with angiotensin II formation was associated with altered expression of inflammation- and carcinogenesis-related proteins. The present results speak in favor of involvement of angiotensin II in BE dysplasia, but the role of AT1R should be investigated further.
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| 23. |
- Bratlie, Svein-Olav, et al.
(författare)
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The renin–angiotensin system in Barrett’s esophagus
- 2016
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 51:9978, s. 1037-1042
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT Objective: Barrett’s esophagus (BE) is a risk factor for esophageal adenocarcinoma. In addition to its classical endocrine character known for hemodynamic regulation, the renin–angiotensin system (RAS) can be associated with inflammation, wound healing, and cancer. The aim of this study was to explore a potential expression of the RAS in BE, with or without the presence of dysplasia. Material and methods: Biopsy material was prepared for western blotting and immunohistochemistry. Non-BE patients (controls) were compared with BE patients regarding RAS in the squamous epithelium. In the columnar BE mucosa, RAS expression was studied in patients with and without dysplasia. Key components of the ‘classical’ RAS were assessed: the angiotensin-converting enzyme (ACE) and the angiotensin II subtype 1 and 2 receptors (AT1R and AT2R). Results: The presence of RAS factors was confirmed in the esophageal mucosa of both control and BE patients. ACE protein expression was 48% lower (p1⁄40.001) whereas AT1R was 45% higher (p1⁄40.039) in the squamous epithelium of BE patients compared to epithelia from non-BE controls. In the meta- plastic intestinal-like epithelium, AT1R expression was 37% higher in BE patients with confirmed dyspla- sia than in patients without dysplasia (p 1⁄4 0.009). Immunohistochemistry showed an altered distribution of RAS proteins in BE patients with dysplasia. Conclusions: The differential RAS expression observed may prove to be useful as a biomarker or a pharmaceutical target.
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| 24. |
- Casselbrant, Anna, 1970, et al.
(författare)
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Actions by angiotensin II on esophageal contractility in humans
- 2007
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Ingår i: Gastroenterology. - : Elsevier BV. - 0016-5085. ; 132:1, s. 249-60
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: Angiotensin II is a potent activator of smooth muscles but has not been much investigated with regard to gastrointestinal motor activity. This study explores expression of the renin-angiotensin system (RAS) in human esophageal musculature and actions by Angiotensin II both in vitro and in vivo. METHODS: Muscular specimens of esophageal body and lower esophageal sphincter were obtained from patients undergoing resection as a result of mucosal neoplasm. Healthy volunteers participated in functional examinations of esophageal motility assessed by high-resolution manometry and multiple transmucosal potential-difference measurements. RESULTS: Gene transcripts of key components of RAS were found in the esophageal musculature. Immunohistochemistry revealed a distinct staining for Angiotensin II type 1 (AT(1)) receptors in the muscular bundles and blood-vessel walls, whereas Angiotensin II type 2 receptors were confined to blood vessels only. Angiotensin II caused concentration-dependent contractions in vitro, which were inhibited by the AT(1) receptor antagonist losartan but not by the Angiotensin II type 2 receptor antagonist PD123319. Administration of the AT(1) receptor antagonist candesartan reduced the amplitude of swallow-induced peristaltic contractions and both the length and pressure amplitude of baseline high-pressure zone at the esophagogastric junction. Neither swallow-induced axial movements, nor the contraction after transient lower esophageal sphincter relaxations, were influenced by candesartan pretreatment. CONCLUSIONS: The study demonstrates a local RAS in the musculature of the distal esophagus and that Angiotensin II is a potent stimulator of esophageal contractions via the AT(1) receptor. The results suggest that Angiotensin II participates in the physiological control of the human esophageal motor activity.
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| 25. |
- Casselbrant, Anna, 1970, et al.
(författare)
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Angiotensin II receptors are expressed and functional in human esophageal mucosa.
- 2009
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Ingår i: American journal of physiology. Gastrointestinal and liver physiology. - : American Physiological Society. - 1522-1547 .- 0193-1857. ; 297:5
-
Tidskriftsartikel (refereegranskat)abstract
- Only few studies have been devoted to the actions of the renin-angiotensin system (RAS) in the human gastrointestinal tract. The present study was undertaken to elucidate the expression and action of RAS in the human esophageal mucosa. Mucosal specimens with normal histological appearance were obtained from healthy subjects undergoing endoscopy and from patients undergoing esophagectomy due to neoplasm. Gene and protein expressions of angiotensin II (Ang II) receptor type 1 (AT(1)) and type 2 (AT(2)) and angiotensin-converting enzyme (ACE) were analyzed. In vivo functionality in healthy volunteers was reflected by assessing transmucosal potential difference (PD). Ussing chamber technique was used to analyze the different effects of Ang II on its AT(1) and AT(2) receptors. Immunoreactivity to AT(1) and AT(2) was localized to stratum superficiale and spinosum in the epithelium. ACE, AT(1), and AT(2) were found in blood vessel walls. Transmucosal PD in vivo increased following administration of the AT(1) receptor antagonist candesartan. In Ussing preparations mean basal transmural PD was -6.4 mV, epithelial current (I(ep)) 34 muA/cm(2), and epithelial resistance (R(ep)) 321 Omega.cm(2). Serosal exposure to Ang II increased PD as a result of increased I(ep), whereas R(ep) was constant. Ang II given together with the selective AT(1)-receptor antagonist losartan, or AT(2) agonist C21 given alone, resulted in a similar effect. Ang II given in presence of the AT(2)-receptor antagonist PD123319 did not influence PD, but I(ep) decreased and R(ep) increased. In conclusion, Ang II receptors and ACE are expressed in the human esophageal epithelium. The results suggest that AT(2)-receptor stimulation increases epithelial ion transport, whereas the AT(1) receptor inhibits ion transport and increases R(ep).
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| 26. |
- Casselbrant, Anna, 1970, et al.
(författare)
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Asymmetric mucosal structure, mesenteric versus antimesenteric, in mouse, rat, and human small intestines
- 2022
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Ingår i: Physiological Reports. - : Wiley. - 2051-817X. ; 10:24
-
Tidskriftsartikel (refereegranskat)abstract
- The morphology of the small intestinal mucosa is reflected by the degree of stimuli. Previous studies have come to different conclusion about whether the mucosa is equally symmetrical. The aim of the study is to investigate whether there are structural differences in the mesenteric versus antimesenteric mucosa in mice, rats, and humans. Jejunal biopsies from mice and rats were saved. Samples from human small intestine were obtained from patients undergoing Roux-en-Y gastric bypass surgery. Fixed samples were used to morphologically evaluate villus height and enlargement factor due to villi. The number of goblet cells, mast cells, enteroendocrine cells, and Paneth cells were histologically analyzed in the villus structure. Cell turnover was analyzed by Ki-67 staining. There was a significant increased villi height and villus enlargement factor antimesenterically in mice, rats, and human small intestines. The distribution of goblet cells, mast cells, and Paneth cells were equal while the number of enteroendocrine cells was increased antimesenteric in the human samples. The crypt mitotic activity was almost 20% higher in the antimesenteric part of jejunum. In summary we found longer villi, greater surface enlargement, and increased number of enteroendocrine cells as well as increased cell turnover antimesenterically. These differences may be of importance in understanding normal gastrointestinal physiology in health and disease.
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| 27. |
- Casselbrant, Anna, 1970, et al.
(författare)
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Effects of fixation on electrophysiology and structure of human jejunal villi
- 2018
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Ingår i: Microscopy Research and Technique. - : Wiley. - 1059-910X. ; 81:4, s. 376-383
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Tidskriftsartikel (refereegranskat)abstract
- The villi of human jejunum vary in size and shape during different functional conditions. In the base the lamina propria is isotonic with blood, in the tip hyperosmotic. Here we study electrophysiological and morphological effects of incubation in hypotonic, isotonic, or hypertonic solutions, and to test various isotonic fixatives for microscopy. Samples of jejunal mucosae, obtained during surgery in obese patients, were studied in Ussing chambers where electrical parameters were registered during incubation in Krebs solution at various osmolarities, and during fixation in formaldehyde, glutaraldehyde, or osmium tetroxide (OsO4). The same fixatives were used for other jejunal specimens that were fixed directly for light microscopy. Morphometry was carried out to determine size and height of villi, proportion of lamina propria, and surface enlargement due to villi. Ussing chamber incubation in fluids with low osmolarity resulted in increased electrical resistance and epithelial swelling. Opposite results were obtained at high osmolality. Fixation was faster in formaldehyde than in glutaraldehyde or OsO4. In biopsies processed directly for light microscopy the proportions of lamina propria of the mucosa, and of lamina propria of villi, were significantly larger in biopsies fixed in formaldehyde than after fixation in glutaraldehyde or OsO4. The villus tips sometimes ended with a bleb with prominent spaces between the epithelial cells. In summary, jejunal villi swell in vitro when exposed to hypotonic solutions, and shrink in hypertonic solutions. Much of the morphological changes occurring during fixation can be related to the physiological hyperosmolar milieu in villus tips.
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| 28. |
- Casselbrant, Anna, 1970, et al.
(författare)
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Luminal Polyethylene Glycol Alleviates Intestinal Preservation Injury Irrespective of Molecular Size
- 2018
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Ingår i: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 366:1, s. 29-36
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Tidskriftsartikel (refereegranskat)abstract
- Intestinal preservation injury (IPI) and the resulting mucosa injury raise several serious challenges early after intestinal transplantation. The current clinical approach using only vascular perfusion allows the shortest preservation period among the abdominal organs. The experimental addition of luminal polyethylene glycol (PEG) solutions has been repeatedly suggested to alleviate preservation injury, improve graft quality, and prolong the preservation time. We investigated whether the molecular mass of PEG in solution influences the development of intestinal preservation injury. Small intestines of Sprague-Dawley rats were perfused with University of Wisconsin solution. Group 1 underwent vascular perfusion only (clinical control), group 2 received additional luminal PEG3350 Da, group 3 received luminal PEG10000 Da, and group 4 received luminal PEG20000 Da (n = 8/group). Tissue samples were obtained after 4, 8, and 14 hours. We studied the tissue damage (Chiu/Park score, Goblet cells, apoptosis, tight junctions), activation of c-Jun NH2-terminal kinase (JNK), and p38-mitogen-activated protein kinase (MAPK), and we performed Ussing chamber assessments. Mucosal morphologic and electrophysiologic parameters were significantly improved in the groups receiving luminal PEG. There was significantly less apoptotic activity in groups 2, 3, and 4. Both MAPKs revealed an activation peak after 4 hours with group 3 showing lesser p38-MAPK activation. PEG 20 kDa interfered with protein immunodetection. The results indicate that luminal solutions of PEG of medium and large molecular mass significantly delay the onset and development of IPI, providing further evidence that luminal interventions may allow for longer cold storage intervals of intestinal grafts.
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| 29. |
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| 30. |
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| 31. |
- Casselbrant, Anna, 1970, et al.
(författare)
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The muscular expression of RAS in patients with achalasia.
- 2015
-
Ingår i: Journal of the renin-angiotensin-aldosterone system : JRAAS. - : Hindawi Limited. - 1752-8976 .- 1470-3203. ; 16:3, s. 578-586
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Tidskriftsartikel (refereegranskat)abstract
- Angiotensin II (AngII) elicits smooth muscle contractions via activation of AngII type 1 receptor (AT1R) in the intestinal wall and in sphincter regions in several species. Achalasia is a rare swallowing disorder and is characterized by a loss of the wave-like contraction that forces food through the oesophagus and a failure of the lower oesophageal sphincter to relax during swallowing.Aims and methods:The present study was undertaken to elucidate expression and distribution of a local renin-angiotensin system (RAS) in the muscular layer of distal normal human oesophagus as well as in patients with achalasia using western blot analysis, immunohistochemistry and polymerase chain reaction (PCR).
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| 32. |
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| 33. |
- Elfvin, Anders, 1971, et al.
(författare)
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Oxidative and nitrosative stress enzymes in relation to nitrotyrosine in Helicobacter pylori -infected humans
- 2014
-
Ingår i: World Journal of Gastrointestinal Pathophysiology. - : Baishideng Publishing Group Inc.. - 2150-5330. ; 5:3, s. 373-379
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To compare a possible relation between Helico- bacter pylori (H. pylori) and the oxygen- and nitrogen radical system in humans. METHODS: Mechanisms for H. pylori to interfere with the oxygen and nitrogen radical system is of great im- portance for understanding of the H. pylori persistence and pathogenesis. Biopsies were obtained from the gastric wall of 21 individuals. Ongoing infection with H. pylori was detected using direct analyze from the biop- sies using campylobacter-like organism test (CLO-test) and/or by using 14C-urea breath test. The individuals were divided in a negative H. pylori and a positive H. pylori group. Expression in the gastric mucosa of induc- ible nitric oxide syntase (iNOS), nicotinamide adenine dinucleotide phosphate-oxidase (NADPH-oxidase) my- eloperoxidase (MPO), and nitrotyrosine were assessed by Western blotting. RESULTS: The individuals who undervent gastroscopy were divided in a H. pylori neg. [n = 13, m/f = 7/6, age(mean)=39]andaH.pylori pos.group[n=8,m/ f = 5/3, age (mean) = 53]. Using western blot analy- sis iNOS was detected as a 130 kDa band. The iNOS expression was upregulated in the antrum of H. pylori infected individuals in comparison to the controls, mean ± SD being 12.6 ± 2.4vs 8.3 ± 3.1,P < 0.01. There was a markedly upregulated expression of MPO in the antrum of H. pylori infected individuals in comparison to the control group without infection. In several of non- infected controls it was not possible to detect any MPO expression at all, whereas the expression was high in all the infected subjects, mean ± SD being 5.1 ± 3.4 vs 2.1 ± 1.9, P < 0.05. The NADPH-oxidase expression was analysed by detecting the NADPH-oxidase subunit p47-phox expression. P47-phox was detected as a 47 kDa band using Western blot, and showed a signifi- cantly higher expression of p47-phox in the antrum of the H. pylori infected individuals compared to the con- trols, mean ± SD being 3.1 ± 2.2vs 0.3 ± 0.2,P < 0.01. Regarding nitrotyrosine formation, Western blot did not show any significant increase or decrease compared to controls, 7.0 ± 0.9 vs 6.9 ± 1.1, not significant. CONCLUSION: iNOS, MPO and NADPH-oxidase was up-regulated among H. pylori infected. Regarding ni- trotyrosine no difference was found. This support an H. pylori related inhibition of radical formation.
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| 34. |
- Hallersund, Peter, 1975, et al.
(författare)
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Angiotensin II receptor expression and relation to Helicobacter pylori-infection in the stomach of the Mongolian gerbil.
- 2010
-
Ingår i: BMC gastroenterology. - 1471-230X. ; 10:3
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The role of the renin-angiotensin system in gastric physiology and disease has as yet been sparsely explored. The first aim of the study was to investigate the baseline presence and location of angiotensin II receptors (AT1R and AT2R) in the stomach of the Mongolian gerbil. A second aim was to elucidate whether the presence of H. pylori infection is associated with changes in the expression of these receptors. METHODS: H. pylori-negative and H. pylori-infected (strain SS1 or TN2GF4) male Mongolian gerbils were investigated. The stomachs were examined at six or 12 months after inoculation by the use of immunohistochemistry, western blot and microscopic morphometry. RESULTS: AT1R and AT2R were located in a variety of cells in the gerbil gastric wall, including a subpopulation of endocrine cells in the antral mucosa and inflammatory cells infiltrating H. pylori-infected stomachs. Gerbils infected with the SS1 strain showed a significantly increased antral AT1R protein expression and an increased number of infiltrating polymorphonuclear leucocytes (PMNs) at 12 months. The AT1R protein expression correlated with the number of PMNs and the antral expression of myeloperoxidase. CONCLUSIONS: Angiotensin II receptors are present in a variety of cells in the gastric wall of the Mongolian gerbil. The results indicate an influence dependent on the H. pylori strain on the gastric AT1R expression and a relationship between gastric AT1R expression and mucosal PMNs infiltration.
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| 35. |
- Hernandez, Nidia Maritza, 1979, et al.
(författare)
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Antibodies to kidney endothelial cells contribute to a "leaky" glomerular barrier in patients with chronic kidney diseases.
- 2012
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Ingår i: American journal of physiology. Renal physiology. - : American Physiological Society. - 1522-1466 .- 1931-857X. ; 302:7
-
Tidskriftsartikel (refereegranskat)abstract
- Anti-endothelial cell antibodies (AECA) are reported to cause endothelial dysfunction but their clinical importance with tissue specific endothelial cells is not clear. We hypothesized that AECA reactive with human kidney endothelial cells (HKEC) may cause renal endothelial dysfunction in patients with chronic kidney diseases. We found that a (p < 0.001) higher fraction of end-stage renal disease patients (ESRD) (56%) have AECA reactive with glomerular endothelial cells as compared to healthy controls (5%). Presence of antibodies was associated with female sex (p < 0.001), systolic hypertension (p < 0.01) and elevated tumour necrosis factor-alpha (TNF-α, p < 0.05). These antibodies markedly decrease expression of adherens and tight junction proteins VE-cadherin, Claudin-1 and ZO-1 and provoked a rapid increase in cytosolic free Ca(2+) and rearrangement of actin filaments in HKEC as compared to controls, followed by an enhancement in protein flux and phosphorylation of VE-cadherin, events associated with augmented endothelial cell permeability. Staining of kidney biopsies from ESRD patients with AECA but not controls demonstrated a marked decrease in adherens and tight junctions in glomerular endothelium, confirming our in vitro data. In summary, our data demonstrate a causal link between AECA and their capacity to induce alterations in glomerular vascular permeability.
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| 36. |
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| 37. |
- Inci, Kamuran, et al.
(författare)
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Expression of protease-activated-receptor 2 (PAR-2) in human esophageal mucosa.
- 2009
-
Ingår i: Scandinavian journal of gastroenterology. - : Informa UK Limited. - 1502-7708 .- 0036-5521. ; 44:6, s. 664-71
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The role of duodenal reflux in gastroesophageal reflux disease (GERD) containing bile salts and pancreatic enzymes (with special attention to trypsin) is still under discussion. Proteinase-activated receptors (PARs) are a novel family and PAR-2 is a unique member of this family because it is activated by trypsin. The aim of the present study was to examine the presence and the position of the PAR-2 receptor in human esophageal mucosa in different subgroups of GERD. MATERIAL AND METHODS: Distal biopsies taken from healthy controls, patients with erosive reflux disease (ERD), patients with specialized intestinal metaplasia (SIM) and adenocarcinoma were analyzed for the PAR-2 receptor with reverse-transcription polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry. RESULTS: Gene transcripts for the PAR-2 receptor were found in all groups, with increased levels in SIM patients compared to controls. However, this visual pattern was not seen for the protein expression of the PAR-2 receptor showing no apparent quantitative differences between the groups. Immunohistochemistry revealed distinct staining for the PAR-2 receptor in the luminal part of the esophageal epithelium. CONCLUSIONS: The localization of the PAR-2 receptor indicates that the receptor can be cleaved and activated by trypsin in duodenogastric esophageal refluxate. The data thus suggest that the trypsin-PAR-2 pathway may be involved in the pathogenesis of GERD.
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| 38. |
- Isaksson, Rebecka, et al.
(författare)
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Direct stimulation of angiotensin II type 2 receptor reduces nitric oxide production in lipopolysaccharide treated mouse macrophages
- 2020
-
Ingår i: European Journal of Pharmacology. - : Elsevier. - 0014-2999 .- 1879-0712. ; 868
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Tidskriftsartikel (refereegranskat)abstract
- The angiotensin II type 2 receptor (AT2) is upregulated after tissue damage and mediates protective functions in the renin-angiotensin-aldosterone system (RAAS). One of these is to inhibit inducible nitric oxide synthase (iNOS) in activated macrophages. In the present study, we assessed the effect of AT2 receptor ligands on nitric oxide production in murine macrophages as a potential assay to determine the functional activity of an AT2 receptor ligand. Mouse macrophage J744.2 and RAW264.7 were cultivated in lipopolysaccharide (LPS) to induce M1 differentiation and increase iNOS expression. Using Griess reagent and spectrophotometric analysis, the nitric oxide levels were determined, while employing Western blot and immunocytochemistry to determine basal protein expression.Using the first reported selective non-peptide AT2 receptor agonist, compound C21, we conclude that activation of AT2 receptor reduces nitric oxide production in M1 macrophages. Furthermore, the AT2 receptor selective ligand compound C38, a regioisomer of C21, reported as a selective AT2 receptor antagonist exhibits a similar effect on nitric oxide production. Thus, we propose C38 acts as a partial agonist in the macrophage system. Monitoring nitric oxide attenuation in M1 J744.1 and RAW264.7 macrophages provides a new method for characterizing functional activity of AT2 receptor ligands, foreseen to be valuable in future drug discovery programs.
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| 39. |
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| 40. |
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| 41. |
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| 42. |
- Mantas, Malinauskas, 1985, et al.
(författare)
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Angiotensin IV induced contractions in human jejunal wall musculature in vitro
- 2014
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Ingår i: Peptides. - : Elsevier BV. - 0196-9781. ; 59:C, s. 63-69
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Tidskriftsartikel (refereegranskat)abstract
- Angiotensin II (AngII) has been reported to mediate contractile actions in rats and human jejunal wall musculature. However, except for one report showing the Angiotensin IV (AngIV) contractile effects on the internal anal sphincter of rats, no data is available describing the action of AngIV on smooth muscle in human small intestine. The aim of this study was to investigate the expression and localization of the enzymes responsible to AngIV formation, as well as the receptor, and to elucidate the contractile function of AngIV in the muscular layer of human jejunum in vitro. Jejunal smooth muscle was taken from 23 patients undergoing Roux-en-Y gastric bypass surgery and was used to record isometric tension in vitro in response to AngIV alone and in presence of losartan or PD123319. ELISA, western blot and immunohistochemistry were used to investigate the expression and localization of key components for AngIV formation: the enzymes Aminopeptidases-A, B, M, and the AngIV receptor insulin-regulated aminopeptidase (IRAP). AngIV elicited concentration-dependent contraction in both longitudinal and circular smooth-muscle preparation. Presence of losartan abolished AngIV-induced contraction, but not PD123319. The main peptide AngII, as well as the enzymes Aminopeptidase-A, B and M were detected in all muscle samples. Immunohistochemistry localized the enzymes and IRAP in the myenteric plexus between longitudinal and circular muscle layers. The present study indicates that all enzymes necessary for AngIV formation exist in human jejunal smooth muscle and that the contractile action elicited by AngIV is primarily mediated through the AngII type 1 receptor.
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| 43. |
- Oltean, Mihai, 1976, et al.
(författare)
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A sequential assessment of the preservation injury in porcine intestines
- 2017
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Ingår i: Journal of Surgical Research. - : Elsevier BV. - 0022-4804. ; 216, s. 149-157
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Clinical and experimental evidence strongly suggest that ischemia-reperfusion injury after intestinal transplantation has deleterious short-and long-term effects and finding means to reduce ischemia-reperfusion injury is a major research area. The anatomical and physiological similarities between the human and porcine digestive tract favor its use as a preclinical model for translational research. Intriguingly, no systematic appraisal of the development of the intestinal preservation injury in pigs is available. Materials and methods: Intestinal procurement was performed in nine pigs using histidine-tryptophan-ketoglutarate solution as preservation fluid. Ileal biopsies were obtained after 8, 14, and 24 h of static cold storage (SCS), and the preservation injury was assessed morphologically (Chiu score) as well as on the molecular level. Tight junction (zonula occludens, claudin-3 and 4, tricellulin, and occludin) and adherens junctions (E-cadherin) proteins were studied using immunofluorescence and Western blot. Results: Eight hours of SCS induced minimal mucosal changes (Chiu grade 1) that advanced to significant subepithelial edema (Chiu grade 3) after 24 h; progressive Goblet cell depletion was also noted. Apoptosis (studied by cleaved caspase-3 staining significantly increased after 24 h of SCS. Significant molecular changes with decreasing expression of zonula occludens, tricellulin, and occludin were evident already after 8 h of SCS and continuously worsened. Claudin-3 and Claudin-4 and E-cadherin expression remained relatively unaltered during SCS. Conclusions: Important molecular alterations precede histologic changes during SCS of the porcine intestine and may be used as more sensitive injury markers than histologic changes in intestinal ischemia and transplantation. (C) 2017 Elsevier Inc. All rights reserved.
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| 44. |
- Oltean, Mihai, 1976, et al.
(författare)
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Intraluminal Polyethylene Glycol Stabilizes Tight Junctions and Improves Intestinal Preservation in the Rat
- 2012
-
Ingår i: American Journal of Transplantation. - : Elsevier BV. - 1600-6135. ; 12:8, s. 2044-2051
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Tidskriftsartikel (refereegranskat)abstract
- Rapidly progressing mucosal breakdown limits the intestinal preservation time below 10 h. Recent studies indicate that intraluminal solutions containing polyethylene glycol (PEG) alleviate preservation injury of intestines stored in UW-Viaspan. We investigated whether a low-sodium PEG solution is beneficial for intestines stored in histidine-tryptophane-ketoglutarate (HTK) preservation solution. Rat intestines used as control tissue (group 1) were perfused with HTK, groups 2 and 3 received either a customized PEG-3350 (group 2) or an electrolyte solution (group 3) intraluminally before cold storage. Tissue injury, brush-border maltase activity, zonula occludens-1 (ZO-1) and claudin-3 expression in the tight junctions (TJ) were analyzed after 8, 14 and 20 h. We measured epithelial resistance and permeability (Ussing chamber) after 8 and 14 h. Group 2 had superior morphology while maltase activity was similar in all groups. TJ proteins rapidly decreased and decolocalized in groups 1 3; these negative events were delayed in group 2, where colocalization persisted for about 14 h. Intestines in group 2 had higher epithelial resistance and lower permeability than the other groups. These results suggest that a customized PEG solution intraluminally reduces the intestinal preservation injury by improving several major epithelial characteristics without negatively affecting the brush-border enzymes or promoting edema.
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| 45. |
- Oltean, Mihai, 1976, et al.
(författare)
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Luminal solutions protect mucosal barrier during extended preservation.
- 2015
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Ingår i: The Journal of surgical research. - : Elsevier BV. - 1095-8673 .- 0022-4804. ; 194:1, s. 289-96
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Tidskriftsartikel (refereegranskat)abstract
- Mucosal barrier injury during intestinal preservation (IP) and transplantation favors life-threatening infections. Luminal delivery of solutions containing amino acids or polyethylene glycols (PEGs) may improve preservation results and reduce this injury. We tested if solutions containing glutamine and PEG influence the mucosal injury.Rat intestines were perfused and stored in Viaspan-University of Wisconsin solution. Before IP, a PEG 3350 solution was introduced intraluminally alone (group 1) or supplemented with 40 mmol/L L-glutamine (group 2). Controls underwent vascular flush alone (group 3). Preservation injury was evaluated after 8, 14, and 24 h by histology and goblet cell count. Tight-junction proteins zonula occludens-1, claudin-3, claudin-4, and caveolin-1 were studied by immunofluorescence. Maltase and caspase-3 activity were also analyzed.Group 1 showed mild edema at 8 h and mucosal disruption by 24 h; these features were greatly improved in group 2 where continuous mucosa was found after 24 h of IP. Intestines in group 3 did worse at all time points with subepithelial edema (Park/Chiu grade 3) and marked goblet cell depletion; caspase-3 activity was lowest in group 2. Tight-junction proteins varied continuously during IP; zonula occludens-1 expression and colocalization with claudins decreased significantly in group 3 but not in other groups. Claudin-3 was distinctly localized in the membrane, but stained diffuse, cytoplasmic at later time-points. Claudin-4 changed to a cytoplasmic granular pattern. No caveolin-1 colocalization was observed.Luminal PEG and glutamine delay epithelial breakdown and preserve several important mucosal features during extended IP.
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| 46. |
- Oltean, Mihai, 1976, et al.
(författare)
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The proteomic signature of intestinal acute rejection in the mouse
- 2022
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Ingår i: Metabolites. - : MDPI AG. - 2218-1989. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Intestinal acute rejection (AR) lacks a reliable non-invasive biomarker and AR surveillance is conducted through frequent endoscopic biopsies. Although citrulline and calprotectin have been suggested as AR biomarkers, these have limited clinical value. Using a mouse model of intestinal transplantation (ITx), we performed a proteome-wide analysis and investigated rejection-related proteome changes that may eventually be used as biomarkers. ITx was performed in allogenic (Balb/C to C57Bl) and syngeneic (C57Bl) combinations. Graft samples were obtained three and six days after transplantation (n = 4/time point) and quantitative proteomic analysis with iTRAQ-labeling and mass spectrometry of whole tissue homogenates was performed. Histology showed moderate AR in all allografts post-transplantation at day six. Nine hundred and thirty-eight proteins with at least three unique peptides were identified in the intestinal grafts. Eighty-six proteins varying by >20% between time points and/or groups had an alteration pattern unique to the rejecting allografts: thirty-seven proteins and enzymes (including S100-A8 and IDO-1) were significantly upregulated whereas forty-nine (among other chromogranin, ornithine aminotransferase, and arginase) were downregulated. Numerous proteins showed altered expression during intestinal AR, several of which were previously identified to be involved in acute rejection, although our results also identified previously unreported proteome changes. The metabolites and downstream metabolic pathways of some of these proteins and enzymes may become potential biomarkers for intestinal AR.
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| 47. |
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| 48. |
- Spak, Emma, 1977, et al.
(författare)
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Angiotensin II-induced contractions in human jejunal wall musculature in vitro.
- 2008
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Ingår i: Acta physiologica (Oxford, England). - : Wiley. - 1748-1716 .- 1748-1708. ; 193:2, s. 181-90
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Tidskriftsartikel (refereegranskat)abstract
- AIM: Angiotensin II is well known for its contractile effects on smooth muscle cells. This effect is also present in the gut previously shown in animal models. The aim of this study was to clarify expression and localization of angiotensin II receptors in the human small intestine and to explore the pharmacological profile of angiotensin II effects in vitro. METHODS: Strips of jejunal muscle wall from 32 patients undergoing bariatric surgery were used to record isometric tension in vitro in response to angiotensin II (10(-10)-10(-5) M) alone and in the presence of PD123319 (10(-7) M), losartan (10(-7) M), PD123319 (10(-7) M) and losartan (10(-7) M) in combination, tetrodotoxin (TTX) (10(-6) M), atropine (10(-6) M) and guanethidine (3 x 10(-6) M). Western blot, immunohistochemistry and RT-PCR were performed on corresponding muscle samples to identify expression and localization of key components of the renin-angiotensin system. RESULTS: Angiotensin II elicited concentration-dependent contraction in both longitudinal and circular jejunal muscle wall strips; neither TTX, atropine nor guanethidine affected this action. Losartan alone and in combination with PD123319 shifted the concentration-response curve to the right. Transcription of angiotensinogen, ACE and angiotensin II types 1 and 2 receptor RNA was detected in all patients. Immunohistochemistry detected angiotensin II type 1 receptors in the musculature; both angiotensin II types 1 and type 2 receptors were found in the myenteric plexus. CONCLUSION: This pharmacological analysis indicates that the contractile action elicited by angiotensin II on jejunal wall musculature is primarily mediated through the angiotensin II type 1 receptor located on the musculature.
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| 49. |
- Spak, Emma, 1977, et al.
(författare)
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Changes in the mucosa of the Roux-limb after gastric bypass surgery.
- 2010
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Ingår i: Histopathology. - : Wiley. - 1365-2559 .- 0309-0167. ; 57:5, s. 680-8
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Roux-en-Y gastric bypass surgery is the most efficient treatment of morbid obesity, but the mechanisms of action are still poorly understood. The aim of this study was to explore the Roux-limb mucosa after gastric bypass surgery, focusing upon basic morphology and inflammation. METHODS AND RESULTS: Jejunal mucosal samples from the Roux-limb were gathered from eight patients at time of surgery and 6-8 months postsurgery. Histological evaluation of inflammation and morphometric investigations were performed, cell proliferation was assessed using immunohistochemistry and inflammatory markers and angiotensin (Ang) II receptors were detected using Western blot. Cell proliferation increased and villous surface area decreased in the Roux-limb mucosa but no signs of active inflammation were observed after surgery. Protein analyses showed increased levels of nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase, myeloperoxidase (MPO) and the Ang II type 1(AT(1)) receptor after surgery, whereas the levels of inducible nitric oxide synthase (iNOS), nitrotyrosine and the Ang II type 2(AT(2)) receptor remained constant. CONCLUSION: These results indicate that the phenotype of the jejunal mucosa changes once exposed to undigested food and the increased microbial load in the Roux-limb after surgery.
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| 50. |
- Spak, Emma, 1977, et al.
(författare)
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The human duodenal mucosa harbors all components for a local renin angiotensin system.
- 2019
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Ingår i: Clinical science (London, England : 1979). - 1470-8736. ; 133:8, s. 971-982
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Tidskriftsartikel (refereegranskat)abstract
- The renin-angiotensin system (RAS) is present in the gastrointestinal (GI) tract but remains to be fully characterized, particularly in man. The duodenum plays a role in both the upper and lower GI regulation, as well as in distant organs. The present study investigates the presence and functional potential of RAS in the human duodenal mucosa of healthy individuals. Endoscopically acquired mucosal biopsies from healthy volunteers were examined using western blot, immunohistochemistry, and ELISA. Functionality was examined by using Ussing chambers and recording duodenal transmucosal potential difference (PD) and motility in vivo Angiotensinogen, Angiotensin II (AngII) and its receptors (AT1R, AT2R) as well as to the RAS associated enzymes renin, ACE, and neprylisin were detected in all samples of duodenal mucosa. Migrating motility complex induced elevations of transmucosal PD were significantly larger after per-oral administration of the AT1R receptor antagonist candesartan. Fasting duodenal motility per se was not influenced by candesartan. The epithelial current produced by duodenal mucosae mounted in Ussing chambers increased significantly after addition of AngII to specimens where the AT1R was blocked using losartan. The epithelial current also increased after addition of the AT2R-selective agonist C21. Immunostaining and pharmacological data demonstrate the presence of a local RAS in the human duodenal mucosa with capacity to influence epithelial ion transport by way of particulary the AT2R.
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