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Objective The impact of stent design on venous patency is not well studied. The purpose of this study was to investigate the effect of stent material burden on endothelial coverage of stented venous segments, which may contribute to vessel healing and patency. Methods Segmented self expanding bare nitinol stents (18 × 50 mm) comprising 5 mm long attached metallic rings separated by 2, 5, or 8 mm gaps were implanted in the inferior vena cava (IVC) of 10 sheep. These stents were designed and manufactured for the purposes of this study. At six, 12, and 24 weeks after implantation the animals were euthanised and the stented vessels harvested for histomorphometric analysis. Three sections from the metallic part as well as the gaps between the struts were reviewed for quantification of endothelialisation after six, 12, and 24 weeks. The intimal thickness over and between the stent struts was measured. The endothelialisation score (graded from 1 for complete luminal endothelialisation to 5 for absence of endothelial cells) was determined. Results All stents were successfully deployed and all 10 sheep survived until the time of harvesting. Macroscopic inspection after 24 weeks showed only partial endothelialisation over stents with 2 mm and 5 mm skipped segments, whereas the stents with 8 mm skipped segments were totally incorporated into the vein wall. After 24 weeks, the mean (SD) neointimal thicknesses over stent struts with 2 mm, 5 mm, and 8 mm skipped segments were 254.0 (51.6), 182.2 (98.1), and 194.6 (101.1) μm, respectively. Comparison of endothelialisation scores of stents over time showed statistically significantly better endothelialisation over stents with 8 mm gaps after 12 and 24 weeks. Conclusion Stent designs providing structural support to veins with larger gaps between the scaffold material appear to lead to faster and more complete endothelialisation as well as a thinner intimal layer.

International journal of molecular sciences 23(9), 5272 (2022). doi:10.3390/ijms23095272 special issue: "Special Issue "Molecular Frontiers in Transplantation-Induced Ischemia Reperfusion Injury" / Special Issue Editor: Dr. Raphaël Thuillier, Guest Editor", Published by Molecular Diversity Preservation International, Basel

ApoE abnormality represents a well-known risk factor for cardiovascular diseases. Beyond its role in lipid metabolism, novel studies demonstrate a complex involvement of apoE in membrane homeostasis and signaling as well as in nuclear transcription. Due to the large spread of apoE isoforms in the human population, there is a need to understand the apoE’s role in pathological processes. Our study aims to dissect the involvement of apoE in heart failure. We showed that apoE-deficient rats present multiple organ damages (kidney, liver, lung and spleen) besides the known predisposition for obesity and affected lipid metabolism (two-fold increase in tissular damages in liver and one-fold increase in kidney, lung and spleen). Heart tissue also showed significant morphological changes in apoE−/− rats, mostly after a high-fat diet. Interestingly, the right ventricle of apoE−/− rats fed a high-fat diet showed more damage and affected collagen content (~60% less total collagen content and double increase in collagen1/collagen3 ratio) compared with the left ventricle (no significant differences in total collagen content or collagen1/collagen3 ratio). In patients, we were able to find a correlation between the presence of ε4 allele and cardiomyopathy (χ2 = 10.244, p = 0.001), but also with right ventricle dysfunction with decreased TAPSE (15.3 ± 2.63 mm in ε4-allele-presenting patients vs. 19.8 ± 3.58 mm if the ε4 allele is absent, p &lt, 0.0001*) and increased in systolic pulmonary artery pressure (50.44 ± 16.47 mmHg in ε4-allele-presenting patients vs. 40.68 ± 15.94 mmHg if the ε4 allele is absent, p = 0.0019). Our results confirm that the presence of the ε4 allele is a lipid-metabolism-independent risk factor for heart failure. Moreover, we show for the first time that the presence of the ε4 allele is associated with right ventricle dysfunction, implying different regulatory mechanisms of fibroblasts and the extracellular matrix in both ventricles. This is essential to be considered and thoroughly investigated before the design of therapeutical strategies for patients with heart failure.

Gut microbes 13(1), 1-21 (2021). doi:10.1080/19490976.2020.1854008, Published by Landes Bioscience, Austin, Tex.

The Pringle maneuver (PM) has been widely used to control blood loss during liver resection. However, hepatic inflow occlusion can also result in hepatic ischemia&ndash, reperfusion injury (IRI), especially in patients with a cholestatic, fibrotic, or cirrhotic liver. Here we investigate a nitric oxide synthase (NOS) inhibitor N-Nitroarginine methyl ester (L-NAME) on IRI after the PM and partial hepatectomy of cholestatic livers induced by bile duct ligation (BDL) in rats. Control group (non-BDL/no treatment), BDL + T group (BDL/L-NAME treatment) and BDL group (BDL/no treatment) were analyzed. Cholestasis was induced by BDL in the L-NAME and BDL group and a 50% partial hepatectomy with PM was performed. L-NAME was injected before PM in the BDL + T group. Hepatocellular damage, portal venous flow, microcirculation, endothelial lining, and eNOS, iNOS, interleukin (IL)-6, and transforming growth factor-&beta, (TGF-&beta, ) were evaluated. Microcirculation of the liver in the BDL + T group tended to be higher. Liver damage and apoptotic index were significantly lower and Ki-67 labeling index was higher in the BDL + T group while iNOS and TGF-&beta, expression was decreased. This was corroborated by a better preserved endothelial lining. L-NAME attenuated IRI following PM and improved proliferation/regeneration of cholestatic livers. These positive effects were considered as the result of improved hepatic microcirculation, prevention of iNOS formation, and TGF-&beta, mRNA upregulation.

Scientific reports 9, 18153 (2019). doi:10.1038/s41598-019-54541-z, Published by Macmillan Publishers Limited, part of Springer Nature, [London]

This paper introduces an improved physiological animal model with diabetic Gottingen minipigs, which focuses on the application of human therapy devices and metabolic system analysis. Based on measurement data-sets collected by metabolic test procedures, a new mathematical minipig model is developed. The model consists of 16 differential equations and describes the diabetic porcine glucose metabolism according to the human model published by Sorensen. In the future, the mathematical model will be used as a basis for controller design and the physiological model for experimental control performance evaluation.

Background Due to the drastic shortage of organ donors, clinicians are increasingly considering the use of deceased after cardiac death donors (DCD). Compatible solutes like Ectoine and Hydroxyectoine are produced by extremophilic bacteria as a cell protectant to survive in harsh environments. We hypothesized that the addition of Hydroxyectoine to Histidine-Tryptophan-Ketoglutarate solution (HTK) could ameliorate cold ischemic preservation injury of DCD livers. Material and methods Rat livers were harvested from male Wistar rats weighing 250-300 g. Three experimental groups (n=5 per group) were studied: (1) CONTROLS: cold static storage in HTK for 24 h, (2) DCD: 30-min warm ischemia time and 24-h cold static storage in HTK, and (3) DCD+Hydroxyectoine: like DCD, but with 24-h cold static storage in HTK+Hydroxyectoine. Viability of the livers was assessed after 24 h of preservation by isolated perfusion for 45 min with oxygenated Krebs-Henseleit buffer solution. Results (mean ±SEM, Control vs. DCD vs. DCD+Hydroxyectoine) Parenchymal enzyme release was significantly lower in DCD+Hydroxyectoine compared to DCD (AST: 9±0.54; 56.8±2.05; 32.2±7.25 U/L, ALT: 9.5±0.5; 37.75±9.6; 17.5±4.17 U/L). Bile production at the end of 45 min reperfusion was significantly higher in DCD+Hydroxyectoine (5.16±1.32; 1.36±0.34; 10.75±2.24 µL/g liver weight/45 min). Malondialdehyde values were significantly lower in DCD+Hydroxyectoine (0.8±0.09, 1.14±0.18, 0.77±0.08 nmol/mL). Intercellular adhesion molecule-1 showed significantly lower values in DCD+Hydroxyectoine (219.07±51.79, 431.9±35.70, 205.2±37.71 pg/mL) and the portal venous pressure at 45 min was lower compared to DCD (20.41±0.12, 27.47±0.45, 22.08±0.78 mmHg). Conclusions Our data provide evidence for the beneficial role of Hydroxyectoine-modified HTK solution for the preservation of DCD livers compared to HTK.

The prognosis for recipients of small liver grafts is poor. The aim of this study was to determine the impact of venous systemic oxygen persufflation (VSOP) with nitric oxide (NO) gas for 30% partial liver preservation and transplantation in rats. After we determined optimal NO concentration as 40 ppm in vitro with the isolated perfused rat liver model, we assessed liver injury and regeneration in vivo at 1, 3, 24 and 168 h after transplantation in the following three groups after 3 h-cold storage (n = 20 per group): control group = static storage; VSOP group = oxygen persufflation and VSOP+NO group = oxygen with NO persufflation. The liver graft persufflation was achieved with medical gas via the suprahepatic vena cava; In comparison with control group after transplantation, VSOP+NO preservation (1) increased portal circulation, (2) reduced AST and ALT release, (3) upregulated hepatic endothelial NO synthase, (4) reduced hepatocyte and bileductule damage and (5) improved liver regeneration. These results suggest that gaseous oxygen with NO persufflation is a novel and safe preservation method for small partial liver grafts, not only alleviating graft injury but also improve liver regeneration after transplantation.

Background: Chemotherapy with L-asparaginase is associated with hepatotoxicity resulting in organ dysfunction in patients with preexisting liver disorders. This study investigated the protective effect of L-carnitine during chemotherapy in a steatotic rat liver model. Methods: Livers from nonsteatotic and steatotic rats were tested in an isolated liver reperfusion model adding L-asparaginase and L-carnitine to the reperfusate. Portal venous pressure (PVP), hepatic oxygen consumption, aspartate aminotransferase, lactate dehydrogenase, glutamate dehydrogenase and α-glutathione S-transferase levels were assessed. Further histopathological analysis was performed and cytotoxicity was verified in vitro. Results:L-Asparaginase induced toxicity in fatty livers whereas low toxicity was observed in normal livers. L-Carnitine induced a decline in PVP and oxygen consumption, and reduced parenchymal and mitochondrial damage in fatty livers. Cytotoxicity of L-asparaginase was not impaired by the presence of L-carnitine. Conclusions: Our study emphasizes the potential of L-carnitine to reduce L-asparaginase-induced hepatotoxicity in patients with preexisting liver disorders.

Hepatitis monthly 16(8), e36821 (2016). doi:10.5812/hepatmon.36821, Published by Tehran

BACKGROUND Results in small bowel transplantation are inferior compared to other solid organ transplantations, among other reasons, due to a specific vulnerability to ischemia/reperfusion injury. New strategies are needed to improve organ storage. Here we compare static cold storage in University of Wisconsin solution to storage supplemented with molecular oxygen gas insufflation. MATERIAL AND METHODS Rat small bowel was retrieved and either stored unoxygenated (UW) or oxygenated (UW+O2) for 18 h at 4°C. Biochemical parameters, mucosal function, Toll-like receptor upregulation, and parameters of structural integrity were evaluated following isolated reperfusion in vitro for 30 min at 37°C. RESULTS Oxygenation showed: ATP concentration was 82 times higher; lactate dehydrogenase release was continuously lower over 30 min; malondialdehyde, a final product of lipid peroxidation (UW+O2 vs. UW; 2.7±0.92 nmol/mL vs. 17.22±10.1 nmol/mL; P0.05) and nitric oxide concentration (0.87±0.27 µmol/L vs. 2.17±0.29 µmol/L; P0.001) were significantly lower; whereas mucosal functional integrity (galactose uptake) was better preserved (0.47±0.18 mg/dL vs. 0.35±0.05 mg/dL). Amelioration of tissue damage could be demonstrated by reduced apoptosis (3.3±1.2 AU vs. 28.4±10 AU; P0.05), and preserved subcellular integrity. Toll-like receptors were significantly less upregulated (TLR2 0.32±0.1 vs. 2.1±1.5-fold and TLR4 1.53±1.14 vs. 11.79±5.4-fold; P0.05). CONCLUSIONS Oxygenated storage is superior to standard storage in University of Wisconsin solution in terms of energetics, tissue damage, and mucosal integrity.

Purpose Recently, Apoliprotein E deficient (ApoE-/-) rats have been generated by genetic manipulation, while the bench-to-bedside relevance of this novel model for coronary stenosis research has not been elucidated. Here, we seek to characterize vascular inflammation and in-stent cross-sectional stenosis (ICS) development in the abdominal aorta of ApoE-/- rats. Methods Trans-abdominal aorta bare-metal stent (Multi-LinkMini Vision, Abbott Vascular Inc., Santa Clara, CA; 2.5 x 8 mm; 12 atm) implantation was performed in ApoE-/- rats (Sigma Aldrich Genetic Engineering, Saint Louis, MO). At 7 and 28 days, quantification of ICS, neointimal (NI) area, injury score and inflammation score was conducted using image analysis software (DISKUS, Hilgers, Königswinter). Blood serum analysis for Interleukin (IL)-6, -8 and -10 and for cholesterol levels was performed. Results Serum cholesterol levels were elevated in ApoE-/- rats (8.63±1.73mmol/l vs. 1.98±0.55mmol/l; p Conclusions In ApoE-/- rats, cholesterol levels as well as pro-inflammatory IL-6 and -8 are upregulated, while anti-inflammatory IL-10 is downregulated. Concomitantly, ApoE-/- rats develop increased ICS after abdominal stent implantation. This novel small animal model enables the characterization of distinctive molecular and mechanical ICS mechanisms in an atherogenic milieu that, notably, renders disposable any miniaturization of tested stents as opposed to mouse models.

World journal of hepatology 9(24), 1030-1039(2017). doi:10.4254/wjh.v9.i24.1030, Published by Beijing Baishideng BioMed Scientific Co., Beijing

Annals of intensive care 2, S17 (2012). doi:10.1186/2110-5820-2-S1-S17 special issue: "Diagnosis and management of intra-abdominal hypertension and abdominal compartment syndrome", Published by Springer, Heidelberg

The increasing shortage of donor organs has led to the increasing use of organs from non-heart-beating donors. We aimed to assess the impact of venous systemic oxygen persufflation (VSOP) supplemented with nitric oxide (NO) gas during the cold storage (CS) of warm ischemia (WI)-damaged experimental liver grafts. Rat livers (n = 5 per group) were retrieved after 30 minutes of WI induced by cardiac arrest (the WI group) and were thereafter preserved for 24 hours by CS in histidine tryptophan ketoglutarate solution. During CS, gaseous oxygen was insufflated via the caval vein with 40 ppm NO (the VSOP-NO group) or without NO (the VSOP group). Cold-stored livers without WI served as controls. Liver viability was assessed after the preservation period by normothermic isolated reperfusion for 45 minutes with oxygenated Krebs-Henseleit buffer. After 45 minutes of reperfusion, the VSOP-NO-treated livers showed significantly lower alanine aminotransferase values than the WI-damaged livers (10.2 ± 0.2 versus 78.2 ± 14.6 IU/L), whereas the control livers showed no differences from the VSOP-NO-treated livers. The mitochondrial enzyme release was lower in the VSOP-NO group (4.0 ± 0.7 IU/L) versus the WI group (18.2 ± 4.9 IU/L). An increased portal vein pressure was observed throughout reperfusion (45 minutes) in the WI group (21.7 ± 0.2 mm Hg) versus the VSOP-NO group (12.2 ± 0.8 mm Hg) and the control group (19.9 ± 0.4 mm Hg). Furthermore, the NO concentration in the perfusate after 5 minutes of reperfusion was highest in the VSOP-NO group. The release of malondialdehyde into the perfusate was significantly reduced in the VSOP-NO group (0.9 ± 0.1 nmol/mL) versus the WI group (31.3 ± 5.3 nmol/mL). In conclusion, the resuscitation of livers after 30 minutes of WI to a level comparable to that of nonischemically damaged livers is possible with VSOP supplemented with NO gas. Moreover, the application of VSOP with NO minimizes the extent of injuries caused by oxygen free radicals during preservation.

In order to reduce the number of animal experiments, the use of non-heart-beating donors (NHBDs) from a commercial abattoir has been proposed. Since the use of slaughterhouse organs is legally not defined as animal experiment, this would fulfil international standards as an alternative to animal experiments. The development of intravascular thrombosis after cardiac arrest negatively impacts organ preservation and thus viability during ischaemic storage and reperfusion. A fibrinolytic preflush with streptokinase might overcome these limitations. Therefore, the functional and histomorphological integrity of kidneys preserved immediately with intact circulation (control group A) and kidneys preserved after cardiac arrest with a 30 min period of warm ischaemia (WI) (group B) was compared with kidneys preflushed with 12.5 kU/L (group C) or 50 kU/L streptokinase (group D) after 30 min WI prior to preservation. We could demonstrate that kidneys preflushed with 12.5 kU/L streptokinase (group C) performed better than those without streptokinase pretreatment after WI (group B). Parameters like oxygen consumption, perfusion pressure, laboratory values, lactate dehydrogenase level and lipidperoxidation were closer to that of the control (group A) than in groups B and D. The higher streptokinase concentration of 50 kU/L (group D) resulted histologically in a more pronounced tissue damage and an attenuated renal function, indicating toxic effects. On the basis of our results we believe streptokinase preflushed slaughterhouse kidneys to be an adequate alternative to organs from laboratory animals with the potential to further reduce the number of animal experiments.

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome are increasingly observed in patients with severe acute pancreatitis (SAP). The aim of this study was to investigate the effects of IAH on pancreatic histology and ultrastructure in a porcine model. We examined 16 intubated and anesthetized domestic pigs with a mean body weight of 50.6 (SD, 3.8) kg. Using a CO2 pneumoperitoneum, the intra-abdominal pressure was increased to 30 mmHg for an investigation period of 6 or 12 h (each study group n = 6). In the control group, the intra-abdominal pressure remained 3.9 (SD, 5.4) mmHg for 12 h. Additional Ringer's solution was infused to maintain cardiac output at the level of controls. After the observation period, specimens were taken for histological and ultrastructural analysis, and animals were killed. Cardiac output did not change when compared with control. Histologically, mild- to moderate-grade necrosis was observed after 12 h of IAH. In the ultrastructural analysis, leukocyte infiltration and swelling of endothelial cells were found. In the acinar cells of the exocrine pancreas, endoplasmic reticulum was dilated, and necrosis was noticed. Mitochondrial damage manifested as cisternal destruction with formation of large vacuoles. In this porcine model, 6 and 12 h of IAH resulted in light-microscopical and ultrastructural changes comparable to pancreatitis in humans. As SAP is often accompanied by IAH, the finding of the underlying study suggests a vicious cycle in which IAH may worsen pancreatitis. Ultimately, these findings are in favor of a decompression in patients with SAP and IAH.

According to a previous study, a pathologically increased intraabdominal pressure (IAP) reduces cardiac output (CO) and results in medium- to high-grade organ damage in a porcine model of the abdominal compartment syndrome (ACS). The purpose of this study was to evaluate whether fluid resuscitation can preserve organ integrity together with CO. We examined 12 domestic pigs with a mean body weight of 48 kg. We used a CO2 pneumoperitoneum to increase the IAP to 30 mmHg in 6 animals, and the others served as control group. The investigation period was 24 h. In addition to a standard infusion regimen, Ringer's solution was infused to maintain CO at the level of control animals. Hemodynamic parameters (ITBV, EVLW, MAP, CVP), urine output, inspiratory pressure, as well as serum parameters (e.g., ALT, lipase, AP, lactate, creatinine) were recorded. In the end histological examination of liver, bowel, kidney, and lung was performed. CO, ITBV, EVLW, and urine output did not change when compared with control. Fluid intake was increased (P0.01) when compared with control (10,570 +/- 1,928 vs. 3,918 +/- 1,042 mL). CVP, MAP, and inspiratory pressure were increased. Serum parameters did not change. Acidosis occurred in the study group. Liver, bowel, kidney, and lung displayed mean- to high-grade damage (P0.01). Although extensive fluid resuscitation preserved CO, diuresis, and serum parameters in this previously described model of the ACS, organ damage occurred. In the clinical regard, these results support decompressive treatment in the presence of pathologically high IAP despite "normalized" parameters.

To investigate the effect of meloxicam on the gut-liver axis after cirrhotic liver resection.Forty-four male Wistar rats were assigned to three groups: (1) control group (CG); (2) bile duct ligation with meloxicam treatment (BDL + M); and (3) bile duct ligation without meloxicam treatment (BDL). Secondary biliary liver cirrhosis was induced via ligature of the bile duct in the BDL + M and BDL groups. After 2 wk, the animals underwent a 50% hepatectomy. In the BDL + M group 15 min prior to the hepatectomy, one single dose of meloxicam was administered. Parameters measured included: microcirculation of the liver and small bowel; portal venous flow (PVF); gastrointestinal (GI) transit; alanine aminotransferase (ALT); malondialdehyde; interleukin 6 (IL-6), transforming growth factor beta 1 (TGF-β1) and hypoxia-inducible factor 1 alpha (HIF-1α) levels; mRNA expression of cyclooxigenase-2 (COX-2), IL-6 and TGF-β1; liver and small bowel histology; immunohistochemical evaluation of hepatocyte and enterocyte proliferation with Ki-67 and COX-2 liver expression.Proliferative activity of hepatocytes after liver resection, liver flow and PVF were significantly higher in CG vs BDL + M and CG vs BDL group (P0.05), whereas one single dose of meloxicam ameliorated liver flow and proliferative activity of hepatocytes in BDL + M vs BDL group. COX-2 liver expression at 24 h observation time (OT), IL-6 concentration and mRNA IL-6 expression in the liver especially at 3 h OT, were significantly higher in BDL group when compared with the BDL + M and CG groups (P0.01, P0.001, P0.01, respectively). Liver and small bowel histology, according to a semi quantitative scoring system, showed better integrity in BDL + M and CG as compared to BDL group. ALT release and HIF-1α levels at 1 h OT were significantly higher in BDL + M compared to CG and BDL group (P0.001 and P0.01, respectively). Moreover, ALT release levels at 3 and 24 h OT were significantly higher in BDL group compared to CG, P0.01. GI transit, enterocyte proliferative activity and number of goblet cells were in favor of meloxicam treatment vs BDL group (P0.05, P0.001, P0.01, respectively). Additionally, villus length were higher in BDL + M as compared to BDL group.One single dose of meloxicam administered after cirrhotic liver resection was able to cause better function and integrity of the remaining liver and small bowel.