| 1. |
- Söfteland, John M., 1977, et al.
(författare)
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Intestinal Preservation Injury: A Comparison Between Rat, Porcine and Human Intestines.
- 2019
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Ingår i: International journal of molecular sciences. - : MDPI AG. - 1422-0067. ; 20:13
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Tidskriftsartikel (refereegranskat)abstract
- Advanced preservation injury (PI) after intestinal transplantation has deleterious short- and long-term effects and constitutes a major research topic. Logistics and costs favor rodent studies, whereas clinical translation mandates studies in larger animals or using human material. Despite diverging reports, no direct comparison between the development of intestinal PI in rats, pigs, and humans is available. We compared the development of PI in rat, porcine, and human intestines. Intestinal procurement and cold storage (CS) using histidine-tryptophan-ketoglutarate solution was performed in rats, pigs, and humans. Tissue samples were obtained after 8, 14, and 24 h of CS), and PI was assessed morphologically and at the molecular level (cleaved caspase-3, zonula occludens, claudin-3 and 4, tricellulin, occludin, cytokeratin-8) using immunohistochemistry and Western blot. Intestinal PI developed slower in pigs compared to rats and humans. Tissue injury and apoptosis were significantly higher in rats. Tight junction proteins showed quantitative and qualitative changes differing between species. Significant interspecies differences exist between rats, pigs, and humans regarding intestinal PI progression at tissue and molecular levels. These differences should be taken into account both with regards to study design and the interpretation of findings when relating them to the clinical setting.
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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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
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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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| 5. |
- Oltean, Mihai, 1976, et al.
(författare)
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Intraluminal Polyethylene Glycol Stabilizes Tight Junctions and Improves Intestinal Preservation in the Rat
- 2012
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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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| 6. |
- 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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| 7. |
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| 8. |
- Oltean, Mihai, 1976, et al.
(författare)
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Optimal Solution Volume for Luminal Preservation: A Preclinical Study in Porcine Intestinal Preservation
- 2016
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Ingår i: Transplantation Proceedings. - : Elsevier BV. - 0041-1345. ; 48:2, s. 532-535
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Tidskriftsartikel (refereegranskat)abstract
- Background. Rodent studies suggest that luminal solutions alleviate the mucosal injury and prolong intestinal preservation but concerns exist that excessive volumes of luminal fluid may promote tissue edema. Differences in size, structure, and metabolism between rats and humans require studies in large animals before clinical use. Methods. Intestinal procurement was performed in 7 pigs. After perfusion with histidine-tryptophan-ketoglutarate (HTK), 40-cm-long segments were cut and filled with 13.5% polyethylene glycol (PEG) 3350 solution as follows: VO (controls, none), V1 (0.5 mL/cm), V2 (1 mL/cm), V3 (1.5 mL/cm), and V4 (2 mL/cm). Tissue and luminal solutions were sampled after 8, 14, and 24 hours of cold storage (CS). Preservation injury (Chiu score), the apical membrane (Z0-1, brush-border maltase activity), and the electrolyte content in the luminal solution were studied. Results. In control intestines, 8-hour CS in HTK solution resulted in minimal mucosal changes (grade 1) that progressed to significant subepithelial edema (grade 3) by 24 hours. During this time, a gradual loss in ZO-1 was recorded, whereas maltase activity remained unaltered. Moreover, variable degrees of submucosal edema were observed. Luminal introduction of high volumes (2 mUmL) of PEG solution accelerated the development of the subepithelial edema and submucosal edema, leading to worse histology. However, ZO-1 was preserved better over time than in control intestines (no luminal solution). Maltase activity was reduced in intestines receiving luminal preservation. Luminal sodium content decreased in time and did not differ between groups. Conclusions. This PEG solution protects the apical membrane and the tight-junction proteins but may favor water absorption and tissue (submucosal) edema, and luminal volumes >2 mL/cm may result in worse intestinal morphology.
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| 9. |
- Oltean, Mihai, 1976, et al.
(författare)
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The microsurgical training programme in Gothenburg, Sweden: early experiences
- 2017
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Ingår i: Journal of Plastic Surgery and Hand Surgery. - : Medical Journals Sweden AB. - 2000-656X .- 2000-6764. ; 51:3, s. 193-198
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Microsurgical techniques are increasingly used in routine surgical practice as well as in biomedical research. The training opportunities at standardised training courses are limited, and no microsurgical training facility or programme existed in Scandinavia before 2013. Methods: A microsurgery laboratory was set up and two different courses were started, aiming separately at biomedical researchers and surgeons. The course for biomedical researchers teaches basic microsurgical skills such as vessel isolation, cannulation, and arterial microvascular suture under magnification. The more advanced course for surgeons focuses on various techniques of microvascular and nerve anastomosis. Both courses use a combination of theory and practice, with emphasis on the practical part, the course for surgeons also includes clinically relevant information. Results: Twelve 5-day courses using both non-living models and exercises on laboratory animals have been conducted and attended by 49 researchers and 44 surgeons. The organisation and the programme of the training courses as well as 'The 4E concept' behind the course (educational curriculum, equipment, ergonomy, and evaluation) are further detailed. Conclusions: We have successfully established the first training laboratory and series of microsurgical training courses in Scandinavia at two different levels. The experience from the first 12 courses shows the need for this type of structured training, and confirms that the microsurgical education curriculums needs to be adapted to participants' prerequisites and expectations, and various difficulty levels should be considered.
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| 10. |
- 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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