Soluble thrombomodulin attenuates sinusoidal obstruction syndrome in rat through suppression of high mobility group box 1

Cilostazol improves the prognosis after hepatectomy in rats with sinusoidal obstruction syndrome

BACKGROUND AND AIM

Safe radical hepatectomy is important for patients with colorectal liver metastases complicated by sinusoidal obstruction syndrome (SOS) after oxaliplatin-based chemotherapy. This study aimed to investigate the impact of preoperative administration of cilostazol (CZ), an oral selective phosphodiesterase III inhibitor, on hepatectomy in rat SOS model.

MATERIAL AND METHODS

Rats were divided into NL (normal liver), SOS (monocrotaline [MCT]-treated), and SOS + CZ (MCT + CZ-treated) groups. MCT or CZ was administered orally, and a 30% partial hepatectomy was performed 48 h after MCT administration. Postoperative survival rates were evaluated (n = 9, for each). Other rats were sacrificed on postoperative days (POD) 1 and 3 and evaluated histologically, immunohistochemically, biochemically, and using transmission electron microscopy (TEM), focusing particularly on SOS findings, liver damage, and liver sinusoidal endothelial cell (LSEC) injury.

RESULTS

The cumulative 10-day postoperative survival rate was significantly higher in the SOS + CZ group than in the SOS group (88.9% vs 33.3%, P = 0.001). Total SOS scores were significantly lower in the SOS + CZ group than in the SOS group on both POD 1 and 3. Serum biochemistry and immunohistochemistry showed that CZ reduced liver damage after hepatectomy. TEM revealed that LSECs were significantly preserved morphologically in the SOS + CZ group than in the SOS group on POD 1 (86.1 ± 8.2% vs 63.8 ± 9.3%, P = 0.003).

CONCLUSION

Preoperative CZ administration reduced liver injury by protecting LSECs and improved the prognosis after hepatectomy in rats with SOS.

Melatonin attenuates monocrotaline-induced hepatic sinusoidal obstruction syndrome in rats via activation of Sirtuin-3

Melatonin possesses potent hepatoprotective properties, but it remains to be elucidated whether melatonin has a therapeutic effect on monocrotaline (MCT)-induced hepatic sinusoidal obstruction syndrome (HSOS). In this study, male Sprague Dawley rats were intraperitoneally injected with melatonin or the same volume of vehicle at 0 and 24 h after MCT intragastric administration. Next, hematoxylin-eosin staining and electron microscopy were performed to evaluate the hepatic sinusoidal injury of rats. Endothelial cell marker RECA-1 was observed by immunohistochemistry. Hepatic oxidative stress was analyzed by detecting malondialdehyde, glutathione S-transferase, and reactive oxygen species. Assessment of liver function was carried out by analysis of serum aspartate aminotransferase, alanine aminotransferase, total bilirubin, and albumin levels. Real-time polymerase chain reaction and Western blot analysis were used to identify liver Sirtuin-3 (SIRT3) and active matrix metallopeptidase 9 (MMP-9) expression. Besides, liver sinusoidal endothelial cells (LSECs) were used for the in vitro functional verification experiment. Specifically, liver histology of the melatonin-treated groups showed that the pathological damages caused by MCT were significantly attenuated, total HSOS scores were decreased, and the elevation of serum hyaluronic acid observed in the model group was also reduced. Moreover, melatonin treatment also improved the survival of rats after partial hepatectomy. Administration of melatonin ameliorated MCT-induced LSECs injury, hepatic oxidative stress, and hepatic dysfunction. Furthermore, melatonin treatment increased SIRT3 expression while attenuating MMP-9 activity in liver tissues. Cell experiment also demonstrated that SIRT3 might mediate the protective effect of melatonin on LSECs. Collectively, our study provided the potential rationale for the application of melatonin for the prevention of MCT-induced HSOS.

Enoxaparin attenuates pyrrolizidine alkaloids-induced hepatic sinusoidal obstruction syndrome by inhibiting oncostatin M expression

BACKGROUND AND AIMS

The definitive treatment for pyrrolizidine alkaloids (PAs)-induced hepatic sinusoidal obstruction syndrome (HSOS) is not available. The effectiveness of anticoagulation therapy remains controversial. The efficacy of low molecular weight heparin (LMWH) should be investigated in patients and animal models, and the underlying mechanism should be explored.

METHODS

The prognosis of patients with PAs-HSOS who received anticoagulation therapy was retrospectively analysed. The effect of enoxaparin on the liver injury was determined in animal models of monocrotaline (MCT)-induced HSOS was determined, and the underlying mechanism was investigated using a murine model.

RESULTS

The cumulative survival rate of patients with PAs-induced HSOS was 60.00% and 90.90% in the non-anticoagulation group and anticoagulation group. Enoxaparin attenuated liver injury effectively in a rat model of MCT-induced HSOS. Additionally, the improvement of severe liver injury was observed in MCT-treated mice after the administration of enoxaparin (40 mg/kg). The alleviation of liver injury was observed in mice with hepatocyte-specific deletion of oncostatin M (Osm△Hep ). In MCT-treated mice administrated with enoxaparin, no significant differences in liver injury were observed between Osm△Hep mice and Osmflox/flox mice. Additionally, adenovirus-mediated overexpression of Osm resulted in severe liver injury in MCT-induced mice after the administration of enoxaparin.

CONCLUSIONS

LMWH attenuated severe liver injury in patients with PAs-Induced HSOS and animal models of MCT-induced HSOS, which provides a rationale for the application of anticoagulation therapy.

Biomarkers for early complications post hematopoietic cell transplantation: Insights and challenges

Hematopoietic cell transplantation is an established curative treatment option for various hematological malignant, and non-malignant diseases. However, the success of HCT is still limited by life-threatening early complications post-HCT, such as Graft Versus Host Disease (GVHD), Sinusoidal Obstruction Syndrome (SOS), and transplant-associated microangiopathy, to name a few. A decade of research in the discovery and validation of novel blood-based biomarkers aims to manage these early complications by using them for diagnosis or prognosis. Advances in this field have also led to predictive biomarkers to identify patients' likelihood of response to therapy. Although biomarkers have been extensively evaluated for different complications, these are yet to be used in routine clinical practice. This review provides a detailed summary of various biomarkers for individual early complications post-HCT, their discovery, validation, ongoing clinical trials, and their limitations. Furthermore, this review also provides insights into the biology of biomarkers and the challenge of obtaining a universal cut-off value for biomarkers.

Clinically relevant model of oxaliplatin-induced sinusoidal obstruction syndrome

AIM

Sinusoidal obstruction syndrome (SOS) induced by oxaliplatin-including chemotherapies (OXCx) is associated with impaired hepatic reserve and higher morbidity after hepatic resection. However, in the absence of an appropriate animal experimental model, little is known about its pathophysiology. This study aimed to establish a clinically relevant reproducible model of FOLFOX-induced SOS and to compare the clinical/histopathological features between the clinical and animal SOS settings.

METHODS

We performed clinical/pathological analyses of colorectal liver metastasis (CRLM) patients who underwent hepatectomy with/without preoperative treatment of FOLFOX (n = 22/18). Male micro-minipigs were treated with 50% of the standard human dosage of the FOLFOX regimen.

RESULTS

In contrast to the monocrotaline-induced SOS model in rats, hepatomegaly, ascites, congestion, and coagulative necrosis of hepatocytes were absent in patients with CRLM with OXCx pretreatment and OXCx-treated micro-minipigs. In parallel to CRLM cases with OXCx pretreatment, OXCx-challenged micro-minipigs exhibited deteriorated indocyanine green clearance, morphological alteration of liver sinusoidal endothelial cells, and upregulated matrix metalloproteinase-9. Using our novel porcine SOS model, we identified the hepatoprotective influence of recombinant human soluble thrombomodulin in OXCx-SOS.

CONCLUSIONS

With distinct differences between monocrotaline-induced rat SOS and human/pig OXCx-SOS, our pig OXCx-SOS model serves as a preclinical platform for future investigations to dissect the pathophysiology of OXCx-SOS and seek preventive strategies.

Endothelial Dysfunction Syndromes after Allogeneic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only therapy with a curative potential for a variety of malignant and non-malignant diseases. The major limitation of the procedure is the significant morbidity and mortality mainly associated with the development of graft versus host disease (GVHD) as well as with a series of complications related to endothelial injury, such as sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD), transplant-associated thrombotic microangiopathy (TA-TMA), etc. Endothelial cells (ECs) are key players in the maintenance of vascular homeostasis and during allo-HSCT are confronted by multiple challenges, such as the toxicity from conditioning, the administration of calcineurin inhibitors, the immunosuppression associated infections, and the donor alloreactivity against host tissues. The early diagnosis of endothelial dysfunction syndromes is of paramount importance for the development of effective prophylactic and therapeutic strategies. There is an urgent need for the better understanding of the pathogenetic mechanisms as well as for the identification of novel biomarkers for the early diagnosis of endothelial damage. This review summarizes the current knowledge on the biology of the endothelial dysfunction syndromes after allo-HSCT, along with the respective therapeutic approaches, and discusses the strengths and weaknesses of possible biomarkers of endothelial damage and dysfunction.

Lung damage created by high tidal volume ventilation in rats with monocrotaline-induced pulmonary hypertension

Background

Rats with chronic hypoxia-induced non-inflammatory pulmonary hypertension (PH) are resistant to ventilator-induced lung injury. We investigated the effect of high tidal volume ventilation in another model of PH, monocrotaline (MCT)-induced PH, which is a type of inflammatory PH.

Methods

PH was induced in rats by subcutaneous injection with 60 mg/kg MCT. Normal control rats, rats at 2 weeks after MCT injection (MCT2), and rats at 3 weeks after MCT injection (MCT3) were ventilated with low tidal volume (LV, 6 mL/kg) or high tidal volume (HV, 35 mL/kg) for 2 h with room air without positive end-expiratory pressure. Arterial oxygen pressure (PaO₂) and Evans blue dye (EBD) extravasation were measured. Hypertensive pulmonary vascular remodeling was assessed morphometrically by the percentage of muscularized peripheral pulmonary arteries (%Muscularization) and the media wall thickness to external diameter ratio, namely percentage medial wall thickness (%MWT). To assess inflammation, lung IκB protein and cytokine mRNA expression levels were assessed.

Results

Baseline mean pulmonary arterial pressure was significantly higher in MCT rats (normal, 15.4 ± 0.5 mmHg; MCT2, 23.7 ± 0.9; and MCT3, 34.5 ± 1.5). After 2-h ventilation, PaO₂ was significantly lower in the HV groups compared with the LV groups in normal and MCT2 rats, but not in MCT3 rats. Impairment of oxygenation with HV was less in MCT3 rats compared with normal and MCT2 rats. Among the HV groups, MCT3 rats showed significantly lower levels of EBD extravasation than normal and MCT2 rats. HV significantly downregulated IκB protein expression in normal and MCT3 rats and increased IL-6, MCP-1, CXCL-1 (MIP-1), and IL-10 mRNA levels in MCT3 rats. %Muscularization, %MWT, and the expression of lung elastin were significantly higher in MCT3 rats than in normal and MCT2 rats.

Conclusion

We found that HV-associated damage might be reduced in MCT-induced PH rats compared with normal rats. The results of this and earlier studies suggest that hypertensive pulmonary vascular structural changes might be protective against the occurrence of ventilator-induced lung injury, irrespective of the etiology of PH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01867-6.

Model difference in the effect of cilostazol on the development of experimental pulmonary hypertension in rats

BACKGROUND

Preventing pulmonary vascular remodeling is a key strategy for pulmonary hypertension (PH). Causes of PH include pulmonary vasoconstriction and inflammation. This study aimed to determine whether cilostazol (CLZ), a phosphodiesterase-3 inhibitor, prevents monocrotaline (MCT)- and chronic hypoxia (CH)-induced PH development in rats.

METHODS

Fifty-one male Sprague-Dawley rats were fed rat chow with (0.3% CLZ) or without CLZ for 21 days after a single injection of MCT (60 mg/kg) or saline. Forty-eight rats were fed rat chow with and without CLZ for 14 days under ambient or hypobaric (air at 380 mmHg) CH exposure. The mean pulmonary artery pressure (mPAP), the right ventricle weight-to-left ventricle + septum weight ratio (RV/LV + S), percentages of muscularized peripheral pulmonary arteries (%Muscularization) and medial wall thickness of small muscular arteries (%MWT) were assessed. Levels of the endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (peNOS), AKT, pAKT and IκB proteins in lung tissue were measured using Western blotting. Monocyte chemotactic protein (MCP)-1 mRNA in lung tissue was also assessed.

RESULTS

mPAP [35.1 ± 1.7 mmHg (MCT) (n = 9) vs. 16.6 ± 0.7 (control) (n = 9) (P < 0.05); 29.1 ± 1.5 mmHg (CH) (n = 10) vs. 17.5 ± 0.5 (control) (n = 10) (P < 0.05)], RV/LV + S [0.40 ± 0.01 (MCT) (n = 18) vs. 0.24 ± 0.01 (control) (n = 10) (P < 0.05); 0.41 ± 0.03 (CH) (n = 13) vs. 0.27 ± 0.06 (control) (n = 10) (P < 0.05)], and %Muscularization and %MWT were increased by MCT injection and CH exposure. CLZ significantly attenuated these changes in the MCT model [mPAP 25.1 ± 1.1 mmHg (n = 11) (P < 0.05), RV/LV + S 0.30 ± 0.01 (n = 14) (P < 0.05)]. In contrast, these CLZ effects were not observed in the CH model. Lung eNOS protein expression was unchanged in the MCT model and increased in the CH model. Lung protein expression of AKT, phosphorylated AKT, and IκB was downregulated by MCT, which was attenuated by CLZ; the CH model did not change these proteins. Lung MCP-1 mRNA levels were increased in MCT rats but not CH rats.

CONCLUSIONS

We found model differences in the effect of CLZ on PH development. CLZ might exert a preventive effect on PH development in an inflammatory PH model but not in a vascular structural change model of PH preceded by vasoconstriction. Thus, the preventive effect of CLZ on PH development might depend on the PH etiology.

Biomarkers for Early Complications of Endothelial Origin After Allogeneic Hematopoietic Stem Cell Transplantation: Do They Have a Potential Clinical Role?

Endothelial cell (EC) dysfunction causes a number of early and life-threatening post hematopoietic stem cell transplant (HCT) complications that result in a rapid clinical decline. The main early complications are graft-vs.-host disease (GVHD), transplant associated thrombotic microangiopathy (TA-TMA), and sinusoidal obstruction syndrome (SOS). Post-HCT endothelial dysfunction occurs as a result of chemotherapy, infections, and allogeneic reactivity. Despite major advances in transplant immunology and improvements in supportive care medicine, these complications represent a major obstacle for successful HCT. In recent years, different biomarkers have been investigated for early detection of post-transplant endothelial cell dysfunction, but few have been validated. In this review we will define GVHD, TA-TMA and SOS, summarize the current data available in HCT biomarker research and identify promising biomarkers for detection and diagnosis of early HCT complications.

Hepatic CEACAM1 expression indicates donor liver quality and prevents early transplantation injury

Although CEACAM1 (CC1) glycoprotein resides at the interface of immune liver injury and metabolic homeostasis, its role in orthotopic liver transplantation (OLT) remains elusive. We aimed to determine whether/how CEACAM1 signaling may affect hepatic ischemia-reperfusion injury (IRI) and OLT outcomes. In the mouse, donor liver CC1 null mutation augmented IRI-OLT (CC1-KO→WT) by enhancing ROS expression and HMGB1 translocation during cold storage, data supported by in vitro studies where hepatic flush from CC1-deficient livers enhanced macrophage activation in bone marrow-derived macrophage cultures. Although hepatic CC1 deficiency augmented cold stress-triggered ASK1/p-p38 upregulation, adjunctive ASK1 inhibition alleviated IRI and improved OLT survival by suppressing p-p38 upregulation, ROS induction, and HMGB1 translocation (CC1-KO→WT), whereas ASK1 silencing (siRNA) promoted cytoprotection in cold-stressed and damage-prone CC1-deficient hepatocyte cultures. Consistent with mouse data, CEACAM1 expression in 60 human donor liver biopsies correlated negatively with activation of the ASK1/p-p38 axis, whereas low CC1 levels associated with increased ROS and HMGB1 translocation, enhanced innate and adaptive immune responses, and inferior early OLT function. Notably, reduced donor liver CEACAM1 expression was identified as one of the independent predictors for early allograft dysfunction (EAD) in human OLT patients. Thus, as a checkpoint regulator of IR stress and sterile inflammation, CEACAM1 may be considered as a denominator of donor hepatic tissue quality, and a target for therapeutic modulation in OLT recipients.

Clinical characteristics, CT signs, and pathological findings of Pyrrolizidine alkaloids-induced sinusoidal obstructive syndrome: a retrospective study

BACKGROUND

One major etiology of hepatic sinusoidal obstruction syndrome (HSOS) in China is the intake of pyrrolizidine alkaloids (PAs). Since PAs-induced HSOS is a rare disease that has not been clearly characterized until now, the aim of this study was to investigate clinical characteristics, CT features, and pathological findings of PA-induced HSOS.

METHODS

This retrospective cohort study included 116 patients with PAs-induced HSOS and 68 patients with Budd-Chiari syndrome from Jan 2006 to Sep 2016. We collected medical records of the patients, and reviewed image features of CT, and analyzed pathological findings.

RESULTS

Common clinical manifestations of PAs-induced HSOS were abdominal distention (98.26%), ascites (100%), jaundice (52.94%), abdominal pain (36.36%). Abnormal liver function was observed in most of PAs-induced HSOS. On CT scan, common findings included: ascites, hepatomegaly, the thickening of gallbladder wall, pleural effusion, patchy liver enhancement, and heterogeneous hypoattenuation. Most of the patients had a low ascitic total protein (< 25 g/L) and a high SAAG (≥ 11.0 g/L). In acute stage, pathologic features were massive sinusoidal dilatation, sinusoidal congestion, the extravasation of erythrocytes, hepatocellular necrosis, the accumulation of macrophages, the deposition of hemosiderin. In subacute stage, complete loss of pericentral hepatocytes, sinusoidal dilatation, the deposition of pigment granules were observed.

CONCLUSIONS

The PAs-induced HSOS patients displayed distinct clinical characteristics, imaging features, and pathological findings, which provided some evidences for the diagnosis of PAs-induced HSOS.

TRIAL REGISTRATION

ChiCTR-DRD-17010709.

Molecular Biomarkers in Drug-Induced Liver Injury: Challenges and Future Perspectives

Drug-induced liver injury (DILI) is one among the common adverse drug reactions and the leading causes of drug development attritions, black box warnings, and post-marketing withdrawals. Despite having relatively low clinical incidence, its potentially severe adverse events should be considered in the individual patients due to the high risk of acute liver failure. Although traditional liver parameters have been applied to the diagnosis of DILI, the lack of specific and sensitive biomarkers poses a major limitation, and thus accurate prediction of the subsequent clinical course remains a significant challenge. These drawbacks prompt the investigation and discovery of more effective biomarkers, which could lead to early detection of DILI, and improve its diagnosis and prognosis. Novel promising biomarkers include glutamate dehydrogenase, keratin 18, sorbitol dehydrogenase, glutathione S-transferase, bile acids, cytochrome P450, osteopontin, high mobility group box-1 protein, fatty acid binding protein 1, cadherin 5, miR-122, genetic testing, and omics technologies, among others. Furthermore, several clinical scoring systems have gradually emerged for the diagnosis of DILI including the Roussel Uclaf Causality Assessment Method (RUCAM), Clinical Diagnostic Scale (CDS), and Digestive Disease Week Japan (DDW-J) systems. However, currently their predictive value is limited with certain inherent deficiencies. Thus, perhaps the greatest benefit would be achieved by simultaneously combining the scoring systems and those biomarkers. Herein, we summarized the recent research progress on molecular biomarkers for DILI to improved approaches for its diagnosis and clinical management.

Recombinant human soluble thrombomodulin ameliorates acetaminophen-induced liver toxicity in mice

Recombinant human soluble thrombomodulin alpha (rhTM) has been developed as an anticoagulant with anti-inflammatory activity. Notably, acetaminophen (APAP) -induced liver disease (AILI) is caused by direct metabolite-induced hepatotoxicity as well as hepatic hyper-coagulation. To evaluate the utility of anticoagulant for the treatment of AILI, rhTM was administered in a mouse AILI model and liver damage was analyzed. AILI was induced in 8-week-old mice by intraperitoneal injection of APAP. rhTM (20 mg/kg) or placebo was injected at the same time as APAP administration. Serum alanine aminotransferase, fibrin degradation products and high-mobility group box 1 levels were significantly decreased in the rhTM-treated group compared with the control group. Furthermore, rhTM reduced the necrotic area and fibrin deposition in liver sections. rhTM suppressed the mRNA expression of heme oxygenase-1, plasminogen activator inhibitor type-1, tissue factors, and inflammatory cytokines compared with the control group. rhTM did not change the hepatic GSH content at 2 h after APAP injection, but restored them at 4 h after the insult. rhTM ameliorated liver damage in mice with AILI, probably via the improvement in liver perfusion induced by it's anticoagulant acitivity, which can lead to the suppression of secondary liver damage.

Assessment of hepatic sinusoidal obstruction syndrome with intravoxel incoherent motion diffusion-weighted imaging: An experimental study in a rat model

BACKGROUND

Intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) parameters may reflect perfusion and diffusion changes in hepatic sinusoidal obstruction syndrome (SOS).

PURPOSE

To investigate the feasibility of IVIM-DWI in the noninvasive assessment of hepatic SOS in an experimental rat model.

STUDY TYPE

Animal study.

POPULATION/SUBJECTS

Forty-four rats were administered different doses (90 or 160 mg/kg) of monocrotaline by gavage either 48 or 72 hours before MRI to induce different degrees of hepatic SOS, and another 10 rats served as controls.

FIELD STRENGTH/SEQUENCE

3T scanner, IVIM-DWI using nine b values (0-800 sec/mm² ).

ASSESSMENT

Histologically, rats were classified as having none (n = 10), mild (n = 8), moderate (n = 19), or severe SOS (n = 17). The apparent diffusion coefficient (ADC) and IVIM-derived parameters (D: true diffusion coefficient, D*: pseudo-diffusion coefficient, and f: perfusion fraction) of the liver parenchyma were measured.

STATISTICAL TESTS

IVIM-DWI parameters were compared according to histologic grades of SOS (none, mild, moderate, and severe), and receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic accuracy.

RESULTS

ADC, D, and f of the liver parenchyma were significantly different according to SOS severity groups (Ps < 0.01) and significantly decreased as SOS severity increased (rho = -0.323, -0.313, and -0.700; P = 0.017, 0.021, and <0.001, respectively). Means of f in none, mild, moderate, and severe SOS were 17.2%, 13.3%, 12.3%, and 11.1%, respectively. Among ADC and IVIM-derived parameters, f provided the highest area under the ROC curves for detecting ≥mild, ≥moderate, and severe SOS (0.991, 0.890, and 0.803, respectively).

DATA CONCLUSION

IVIM-DWI may be useful in the diagnosis and severity assessment of hepatic SOS.

LEVEL OF EVIDENCE

2 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:81-89.

Plasma From Patients Undergoing Liver Transplantation Is Resistant to Anticoagulant Activity of Soluble Thrombomodulin

Recombinant human soluble thrombomodulin (ART-123) is an anticoagulant and anti-inflammatory agent clinically used for treatment of disseminated intravascular coagulation. Preclinical studies have shown that ART-123 reduces hepatic ischemia/reperfusion. Although ART-123 may therefore have clinical benefit in orthotopic liver transplantation, the substantial alterations in the hemostatic system may complicate its use in this setting. Here, we studied the in vitro effect of ART-123 on coagulation of patients with end-stage liver disease undergoing liver transplantation. Ten patients with end-stage liver disease undergoing liver transplantation were included in this study. Plasma samples of 10 healthy individuals were included to establish reference values. Different concentrations of ART-123 were added to plasma samples, and peak thrombin generation and clot lysis times (CLTs) were determined. In patient samples, plasma was profoundly resistant to the anticoagulant action of ART-123, as reflected by significantly higher median inhibitory concentration (IC₅₀ ) values of peak thrombin generation compared with controls. This might be partially explained by low levels of protein C, protein S, and elevated levels of factor VIII during transplantation. Intraoperative levels of thrombin activatable fibrinolysis inhibitor were significantly lower when compared with controls. However, ART-123-dependent prolongation of CLTs was not significantly different from healthy controls. In conclusion, this study suggests that ART-123 is unlikely to provoke bleeding in patients undergoing liver transplantation because proposed clinical dosages have a virtually absent anticoagulant effect in these patients. Clinical studies are required to confirm the safety of ART-123 and efficacy on alleviating ischemia/reperfusion injury during liver transplantation.

The Evolving Role of Neutrophils in Liver Transplant Ischemia-Reperfusion Injury

Purpose of Review

Hepatic ischemia-reperfusion injury (IRI), an inevitable event during liver transplantation, represents a major risk factor for the primary graft dysfunction as well as the development of acute and chronic rejection. Neutrophils, along macrophages, are pivotal in the innate immune-driven liver IRI, whereas the effective neutrophil-targeting therapies remain to be established. In this review, we summarize progress in our appreciation of the neutrophil biology and discuss neutrophil-based therapeutic perspectives.

Recent Findings

New technological advances enable to accurately track neutrophil movements and help to understand molecular mechanisms in neutrophil function, such as selective recruitment to IR-stressed tissue, formation of neutrophil extracellular traps, or reverse migration into circulation. In addition to pro-inflammatory and tissue-destructive functions, immune regulatory and tissue-repairing phenotype associated with distinct neutrophil subsets have been identified.

Summary

Newly recognized and therapeutically attractive neutrophil characteristics warrant comprehensive preclinical and clinical attention to target IRI in transplant recipients.

Soluble Thrombomodulin Attenuates Endothelial Cell Damage in Hepatic Sinusoidal Obstruction Syndrome

BACKGROUND

Hepatic sinusoidal obstruction syndrome (SOS), also known as veno-occlusive disease, is a form of drug-induced liver injury, the initial morphological changes associated with which occur in liver sinusoidal endothelial cells (LSECs). Recombinant human soluble thrombomodulin (rTM) is reported to have anti-inflammatory and cytoprotective effects. Therefore, we investigated the ability of rTM to protect endothelial cells and enhance their functions in a monocrotaline (MCT)-induced model of SOS.

MATERIALS AND METHODS

Human umbilical vein endothelial cells were assessed in vitro following administration of MCT (2-4 mM) with/without rTM (10-100 ng/ml) to investigate the effect of rTM on cell proliferation and apoptosis. In vivo experiments were performed with Crl:CD1 mice divided into three groups: rTM (rTM + MCT), placebo (control diluent + MCT), and control (control diluent only). LSECs [cluster of differentiation (CD) 31+CD34+ vascular endothelial growth factor receptor 3 (VEGFR3)+ cells] from these mice were identified using fluorescence-activated cell sorting and assessed by quantitative real-time polymerase chain reaction (qPCR).

RESULTS

In vitro, caspase-3 and -7 activities were significantly lower and cell viability (as assessed by MTT assays) significantly higher in the rTM group than in the placebo group. Moreover, levels of p-AKT increased upon rTM administration. In vivo, damage to LSECs in zone 3 of the hepatic acinus was attenuated and the number of LSECs were maintained in the rTM group, in contrast to the placebo group. Furthermore, expression of Nos3 (encoding endothelial nitric oxide synthase) was higher and that of plasminogen activator inhibitor 1 (Pai1) lower in LSECs from mice in the rTM group than in those from the placebo group.

CONCLUSION

rTM can attenuate SOS by protecting LSECs and enhancing their functions.

A Critical Analysis of Experimental Animal Models of Sinusoidal Obstruction Syndrome

Given the high mortality rate and clinical impact associated with sinusoidal obstruction syndrome (SOS), many studies have attempted to better characterize the disease and potential treatment strategies. However, the unpredictability of SOS onset represents a major obstacle when developing reproducible and controlled clinical trials in humans. Similarly, although in vitro studies have elucidated many of the molecular and cellular mechanisms of SOS, they often lack clinical relevance and translatability, highlighting the importance of experimental in vivo research. Animal models have greatly varied in the approach used to induce SOS in accordance with the numerous causes of human disease. Thus far, the most common and prevalent model is the monocrotaline-induced model in rats, which has served as the basis for both new diagnostic and treatment studies and has been revised over the last 20 years to optimize its use. Furthermore, radiotherapy, oxaliplatin-based chemotherapy, and even hematopoietic stem cell transplantation have been recently used to better replicate human SOS in animals. Nevertheless, because of the novelty of such research, further studies should be conducted to better understand the reproducibility and applicability of these newer models. Thus, this review seeks to summarize the methods and results of experimental in vivo models of SOS and compare the efficacy of these various adaptations.

Magnesium isoglycyrrhizinate has hepatoprotective effects in an oxaliplatin‑induced model of liver injury

Oxaliplatin is a core chemotherapeutic agent used for the treatment of colorectal liver metastasis; however, liver injury caused by oxaliplatin increases the risk of peri‑operative morbidity and mortality. Magnesium isoglycyrrhizinate (MgiG) is a magnesium salt of 18‑α glycyrrhizic acid stereoisomer that has demonstrated liver‑protective effects against toxins and hepatitis. In the present study, the liver‑protective effect of MgiG against oxaliplatin‑induced hepatic injury was examined in vitro and in vivo. The results demonstrated that MgiG had a protective effect against oxaliplatin‑induced liver injury, as evidenced by the alleviation of hepatic pathological damage and transaminase levels. The protective effect of MgiG was demonstrated to be correlated with inhibition of oxidative stress, the interleukin‑6 pathway and the coagulation system. Altogether, the present findings suggested that MgiG may have potential value in the clinical prevention and treatment of oxaliplatin‑induced liver injury.

The lectin like domain of thrombomodulin is involved in the defence against pyelonephritis

Pyelonephritis, a common complication of urinary tract infections, is frequently associated with kidney scarring and may lead to end-stage renal disease. During bacterial infections inflammatory and coagulation pathways and their mutual interaction are playing pivotal roles in the host response. Given that thrombomodulin (TM) is crucially involved in the interplay between coagulation and inflammation, we aimed to investigate the roles of its EGF and lectin-like domains in inflammation during acute pyelonephritis. Indeed, the EGF-like and the lectin-like domains of TM, are especially known to orchestrate inflammation and coagulation in different ways. Acute pyelonephritis was induced by intravesical inoculation of 1 × 10(8) CFU of uropathogenic Escherichia coli in two strains of TM transgenic mice. TM(pro/pro) mice carry a mutation in the EGF-like domain making them unable to activate protein C, an anticoagulant and anti-inflammatory protein. TM(LeD/LeD) mice lack the lectin-like domain of TM, which is critical for its anti-inflammatory and cytoprotective properties. Mice were sacrificed 24 and 48 h after inoculation. Bacterial loads, the immune response and the activation of coagulation were evaluated in the kidney and the bladder. TM(LeD/LeD) mice showed elevated bacterial load in bladder and kidneys compared to WT mice, whereas TM(pro/pro) had similar bacterial load as WT mice. TM(LeD/LeD) mice displayed a reduced local production of pro-inflammatory cytokines and neutrophil renal infiltration. Activation of coagulation was comparable in TM(LeD/LeD) and WT mice. From these data, we conclude that the lectin-like domain of thrombomodulin is critically involved in host defence against E. coli induced acute pyelonephritis.

Thrombomodulin protects against lung damage created by high level of oxygen with large tidal volume mechanical ventilation in rats

Background

Ventilator-induced lung injury (VILI) is associated with inflammatory responses in the lung. Thrombomodulin (TM), a component of the coagulation system, has anticoagulant and anti-inflammatory effects. We hypothesized that the administration of recombinant human soluble TM (rhsTM) would block the development of lung injury.

Methods

Lung injury was induced by high tidal volume ventilation for 2 h with 100% oxygen in rats. Rats were ventilated with a tidal volume of 35 ml/kg with pretreatment via a subcutaneous injection of 3 mg/kg rhsTM (HV (high tidal volume)/TM) or saline (HV/SAL) 12 h before mechanical ventilation. Rats ventilated with a tidal volume of 6 ml/kg under 100% oxygen with rhsTM (LV (low tidal volume)/TM) or saline (LV/SAL) were used as controls. Lung protein permeability was determined by Evans blue dye (EBD) extravasation.

Results

Lung injury was successfully induced in the HV/SAL group compared with the LV/SAL group, as shown by the significant decrease in arterial oxygen pressure (PaO₂), increased protein permeability, and increase in mean pulmonary artery pressure (mPAP) and ratio of mean pulmonary artery pressure to mean artery pressure (Pp/Ps). Treatment of rats with lung injury with rhsTM (HV/TM) significantly attenuated the decrease in PaO₂ and the increase in both mPAP and Pp/Ps, which was associated with a decrease in the lung protein permeability. Lung tissue mRNA expressions of interleukin (IL)-1α, IL-1β, IL-6, tumor necrosis factor-α, and macrophage inflammatory protein (MIP)-2 were significantly higher in HV than in LV rats. Rats with VILI treated with rhsTM (HV/TM) had significantly lower mRNA expressions of IL-1α, IL-1β, IL-6, and MIP-2 than those expressions in HV/SAL rats.

Conclusions

Administration of rhsTM may prevent the development of lung injury created by high level of oxygen with large tidal volume mechanical ventilation, which has concomitant decrease in proinflammatory cytokine and chemokine expression in the lung.