Rifaximin Prevents Intestinal Barrier Dysfunction and Alleviates Liver Injury in MCT-induced HSOS Mice.

OBJECTIVE: Rifaximin is an effective component of treatment strategies for liver and intestinal diseases. However, the efficacy of rifaximin in hepatic sinusoidal obstruction syndrome (HSOS) has not been explored. The present study aimed to investigate the efficacy and mechanism of rifaximin in HSOS. METHODS: An HSOS model was established in mice through the administration of monocrotaline (MCT, 800 mg/kg), and part of the HSOS mice were intragastrically administered with rifaximin. Then, the efficacy of rifaximin in HSOS was evaluated based on the liver pathological findings, liver proinflammatory cytokines, and alanine aminotransferase and aspartate aminotransferase levels. The Ussing chamber was used to evaluate the intestinal permeability, and tight junction (TJ) proteins were measured by Western blotting and real-time polymerase chain reaction to evaluate the intestinal barrier integrity. Then, the serum proinflammatory cytokine levels were evaluated by enzyme-linked immunosorbent assay. Afterwards, an in vitro experiment was performed to determine the relationship between rifaximin and TJ proteins. RESULTS: Rifaximin effectively alleviated the MCT-induced HSOS liver injury, suppressed the expression of liver proinflammatory cytokines, and reduced the serum levels of tumor necrosis factor-alpha and interleukin-6. Furthermore, rifaximin reduced the intestinal permeability, improved the intestinal barrier integrity, and promoted the expression of TJ proteins. CONCLUSION: The results revealed that the intestinal barrier integrity was destroyed in MCT-induced HSOS. The significant alleviation of MCT-induced HSOS induced by rifaximin might be correlated to the repairment of intestinal barrier integrity via the regulation of the TJ protein expression.

Andrographolide attenuated MCT-induced HSOS via regulating NRF2-initiated mitochondrial biogenesis and antioxidant response.

Hepatic sinusoidal obstruction syndrome (HSOS) is a death-dealing liver disease with a fatality rate of up to 67%. In the study present, we explored the efficacy of andrographolide (Andro), a diterpene lactone from Andrographis Herba, in ameliorating the monocrotaline (MCT)-induced HSOS and the underlying mechanism. The alleviation of Andro on MCT-induced rats HSOS was proved by biochemical index detection, electron microscope observation, and liver histological evaluation. Detection of hepatic ATP content, mitochondrial DNA (mtDNA) copy number, and protein expression of nuclear respiratory factor-1 (NRF1) and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PPARGC1A) demonstrated that Andro strengthened mitochondrial biogenesis in livers from MCT-treated rats. Chromatin immunoprecipitation assay exhibited that Andro enhanced the occupation of nuclear factor erythroid 2-related factor 2 (NFE2L2, also known as NRF2) in the promoter regions of both PPARGC1A and NRF1. Andro also activated the NRF2-dependent anti-oxidative response and alleviated liver oxidative injury. In Nrf2 knock-out mice, MCT induced more severe liver damage, and Andro showed no alleviation in it. Furthermore, the Andro-activated mitochondrial biogenesis and anti-oxidative response were reduced in Nrf2 knock-out mice. Contrastingly, knocking out Kelch-like ECH-associated protein 1 (Keap1), a NRF2 repressor, reduced MCT-induced liver damage. Results from co-immunoprecipitation, molecular docking analysis, biotin-Andro pull-down, cellular thermal shift assay, and surface plasmon resonance assay showed that Andro hindered the NRF2-KEAP1 interaction via directly binding to KEAP1. In conclusion, our results revealed that NRF2-dependent liver mitochondrial biogenesis and anti-oxidative response were essential for the Andro-provided alleviation of the MCT-induced HSOS. Graphical Headlights: 1. Andro alleviated MCT-induced HSOS via activating antioxidative response and promoting mitochondrial biogenesis. 2. Andro-activated antioxidative response and mitochondrial biogenesis were NRF2-dependent. 3. Andro activated NRF2 via binding to KEAP1.

Effects of bicyclol on hepatic sinusoidal obstruction syndrome induced by Gynura segetum.

BACKGROUND: The intake of Gynura segetum, a traditional Chinese medicine, may be induce hepatic sinusoidal obstruction syndrome (HSOS). It has a high mortality rate based on the severity of the disease and the absence of therapeutic effectiveness. Therefore, the current study was designed to investigate the effects of bicyclol on HSOS induced by Gynura segetum and the potential molecular mechanisms. METHODS: Gynura segetum (30 g/kg) was administered for 4 weeks in the model group, while the bicyclol pretreatment group received bicyclol (200 mg/kg) administration. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), cholesterol (CHO), triglyceride (TG), and liver histological assays were detected to assess HSOS. The gene expressions of cytochrome P450 (CYP450) isozymes were quantified by real-time PCR. Moreover, hepatocellular apoptosis was detected using the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, then apoptosis and autophagy-related markers were determined using Western blot. RESULTS: As a result, bicyclol pretreatment is notably protected against Gynura segetum-induced HSOS, as observed by reducing serum ALT levels, inhibiting the reduction in CHO and TG levels, and alleviating the histopathological changes. Bicyclol pretreatment inhibited the changes in mRNA levels of CYP450 isozymes (including the increase in CYP2a5 and decrease in CYP2b10, 2c29, 2c37, 3a11, and 7b1). In addition, the upregulation of Bcl-2 and the downregulation of LC3-II/LC3-I proteins expression in HSOS were inhibited with bicyclol pretreatment. CONCLUSION: Bicyclol exerted a protective effect against HSOS induced by Gynura segetum, which could be attributed to the regulated expressions of CYP450 isozymes and alleviated the downregulation of autophagy.

A TMT-based shotgun proteomics uncovers overexpression of thrombospondin 1 as a contributor in pyrrolizidine alkaloid-induced hepatic sinusoidal obstruction syndrome.

Hepatic sinusoidal obstruction disease (HSOS) is a rare but life-threatening vascular liver disease. However, its underlying mechanism and molecular changes in HSOS are largely unknown, thus greatly hindering the development of its effective treatment. Hepatic sinusoidal endothelial cells (HSECs) are the primary and essential target for HSOS. A tandem mass tag-based shotgun proteomics study was performed using primary cultured HSECs from mice with HSOS induced by senecionine, a representative toxic pyrrolizidine alkaloid (PA). Dynamic changes in proteome were found at the initial period of damage and the essential role of thrombospondin 1 (TSP1) was highlighted in PA-induced HSOS. TSP1 over-expression was further confirmed in human HSECs and liver samples from patients with PA-induced HSOS. LSKL peptide, a known TSP1 inhibitor, protected mice from senecionine-induced HSOS. In addition, TSP1 was found to be covalently modified by dehydropyrrolizidine alkaloids in human HSECs and mouse livers upon senecionine treatment, thus to form the pyrrole-protein adduct. These findings provide useful information on early changes in HSECs upon PA treatment and uncover TSP1 overexpression as a contributor in PA-induced HSOS.

Constructing vascularized hepatic tissue by cell-assembled viscous tissue sedimentation method and its application for vascular toxicity assessment.

In vitro Construction of the liver sinusoidal structure using artificial tissue is an important but worthwhile challenge, particularly for assessing the risk of diseases such as sinusoidal obstruction syndrome (SOS). Current models are unsuitable for evaluating the toxicity because of lacking sinusoidal capillary. In this study, we developed a vascularized hepatic tissue (VHT) using a unique tissue engineering technique, the cell assembled viscous tissue by sedimentation (CAViTs) method. The "viscous bodies" created using the CAViTs method exhibited significant self-assembly within 6 h after seeding, promoting cell-cell interaction. The level of albumin secreted by the VHT was four times higher than that of 2D-coculture and maintained for 1 month. The gene expression pattern of the VHT was closer to that of total human liver, compared with the 2D system. Quantitative evaluations of the vascular structure of VHT treated with two typical SOS-inducing compounds, monocrotaline and retrorsine, revealed higher sensitivity (IC50 = 40.35 µM), 19.92 times higher than the cell-viability assay. Thus, VHT represents an innovative in vitro model that mimics the vessel network structure and could become a useful tool for the early screening of compounds associated with a risk of vascular toxicity. STATEMENT OF SIGNIFICANCE: Mimicking sinusoidal structures in in vitro liver model is important to consider from the perspective of predicting hepatotoxicity such like sinusoidal obstruction syndrome (SOS). However, it was difficult to reconstruct the vascular structure within the hepatocyte-rich environment. In this study, we constructed a vascularized hepatic tissue in a high-throughput manner by a unique method using collagen and heparin, and evaluated its applicability to toxicity assessment. Vessel morphology analysis of the model treated by monocrotaline, which is a well-known SOS-inducing compound, could predict the toxicity with higher sensitivity. To the best of our knowledge, this is the first report to provide vascularized hepatic tissues using sinusoidal endothelial cells at least for demonstrating applicability to the evaluation of SOS induction risk.

Metabolic Toxification of 1,2-Unsaturated Pyrrolizidine Alkaloids Causes Human Hepatic Sinusoidal Obstruction Syndrome: The Update.

Saturated and unsaturated pyrrolizidine alkaloids (PAs) are present in more than 6000 plant species growing in countries all over the world. They have a typical heterocyclic structure in common, but differ in their potential toxicity, depending on the presence or absence of a double bond between C1 and C2. Fortunately, most plants contain saturated PAs without this double bond and are therefore not toxic for consumption by humans or animals. In a minority of plants, however, PAs with this double bond between C1 and C2 exhibit strong hepatotoxic, genotoxic, cytotoxic, neurotoxic, and tumorigenic potentials. If consumed in error and in large emouns, plants with 1,2-unsaturated PAs induce metabolic breaking-off of the double bonds of the unsaturated PAs, generating PA radicals that may trigger severe liver injury through a process involving microsomal P450 (CYP), with preference of its isoforms CYP 2A6, CYP 3A4, and CYP 3A5. This toxifying CYP-dependent conversion occurs primarily in the endoplasmic reticulum of the hepatocytes equivalent to the microsomal fraction. Toxified PAs injure the protein membranes of hepatocytes, and after passing their plasma membranes, more so the liver sinusoidal endothelial cells (LSECs), leading to life-threatening hepatic sinusoidal obstruction syndrome (HSOS). This injury is easily diagnosed by blood pyrrolizidine protein adducts, which are perfect diagnostic biomarkers, supporting causality evaluation using the updated RUCAM (Roussel Uclaf Causality Assessment Method). HSOS is clinically characterized by weight gain due to fluid accumulation (ascites, pleural effusion, and edema), and may lead to acute liver failure, liver transplantation, or death. In conclusion, plant-derived PAs with a double bond between C1 and C2 are potentially hepatotoxic after metabolic removal of the double bond, and may cause PA-HSOS with a potential lethal outcome, even if PA consumption is stopped.

miR-511-3p promotes hepatic sinusoidal obstruction syndrome by activating hedgehog pathway via targeting Ptch1.

As a major complication of hematopoietic stem cell transplantation, the incidence of hepatic sinusoidal obstruction syndrome (HSOS) is as high as 70%. Previous evidence has demonstrated that miR-511-3p was involved in HSOS, but the mechanism remains unclear. This study aims to examine the mechanism underlying miR-511-3p regulating HSOS. Monocrotaline (MCT) was used to create an HSOS rat model and to treat liver sinusoidal endothelial cells (LSECs). Hematoxylin & eosin (H&E) and Masson staining were used to detect pathological changes in liver tissue. The expression of miR-511-3p and Hedgehog pathway-related proteins was assessed by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. The effect of miR-511-3p in regulating HSOS was investigated by 3-(4,5)-dimethylthiahiazo-2)-3,5-diphenytetrazoliumromide (MTT), enzyme-linked immunosorbent assay (ELISA) assay, and flow cytometry. Finally, the interaction between miR-511-3p and patched1 (Ptch1) was determined by luciferase reporter assay. The rats showed a typical HSOS phenotype, including LSEC damage, liver injury, and fibrosis after MCT administration. miR-511-3p was upregulated in hepatic tissue of rat HSOS model and MCT-induced LSECs. miR-511-3p directly targeted Ptch1 and suppressed Ptch1 expression to activate the Hedgehog signaling pathway. Depletion of miR-511-3p showed a protective effect against MCT-induced HSOS, as evidenced by decreased HSOS pathogenesis factors, matrix metalloproteinases-2 (MMP-2), matrix metalloproteinases-9 (MMP-9), tumor necrosis factor-α (TNF-α), and interleukin 1 ß (IL-1ß), and decreased LSEC apoptosis rates. Nevertheless, knockdown of Ptch1 reversed the protective effect of miR-511-3p depletion against MCT-induced LSEC injury and apoptosis. miR-511-3p aggravates HSOS by activating the Hedgehog signaling pathway through targeting Ptch1, and miR-511-3p may develop as the potential therapy for the treatment of HSOS.NEW & NOTEWORTHY miR-511-3p is upregulated in HSOS in vivo and in vitro models. miR-511-3p activates the Hedgehog pathway by directly targeting Ptch1. Knockdown of miR-511-3p shows a protective effect against LSEC injury and apoptosis via Hedgehog signaling pathway. Inhibition of Ptch1 reserves the effect of miR-511-3p knockdown on LSEC damage and apoptosis.

The protective effects of umbilical cord-derived endothelial colony forming cells on hepatic veno-occlusive disease.

Hepatic veno-occlusive disease (HVOD) characterized by endothelial cell dysfunction is one of the serious complications after hematopoietic stem-cell transplantation or chemotherapeutic drug application. The mortality of HVOD patients with multiorgan dysfunction is as high as 80%. The primary aim of this study was to evaluate whether the infusion of human umbilical cord-derived endothelial colony forming cells (hUC-ECFCs) could mitigate HVOD injury and investigate the underlying mechanism. We found that the expression of chemokine C-X-C chemokine ligand 12 (CXCL12) was markedly increased in the livers of HVOD mice. Meanwhile, hUC-ECFCs infusion could significantly ameliorate liver injury in HVOD mice, which was accompanied by hUC-ECFCs recruitment in the liver, reduced liver pathological alterations, and decreased serum alanine aminotransferase and aspartate aminotransferase activity. Besides, CXCL12-induced migration in hUC-ECFCs was partly impeded by chemokine receptor type 7 (CXCR7) silence or CXCR4 blockage. In conclusion, our results demonstrated that hUC-ECFCs could mitigate HVOD through homing to the injured liver via the CXCL12-CXCR4/CXCR7 signaling pathway.

Inhibitory Effects of Beraprost Sodium in Murine Hepatic Sinusoidal Obstruction Syndrome.

BACKGROUND/AIM: In this study, the liver sinusoidal endothelial cells (LSECs)-protective effects of beraprost sodium (BPS) were investigated using mice with monocrotaline (MCT)-induced sinusoidal obstruction syndrome (SOS). MATERIALS AND METHODS: The mice were divided into BPS, placebo and control groups. They were killed 48 h after MCT administration, and blood samples and liver tissues were evaluated. Immunostaining was performed using anti-SE-1 and anti-CD42b antibodies, whereas plasminogen activator inhibitor (PAI-1) and endothelial nitric oxide synthase (eNOS) levels were evaluated using western blot or real-time RT-PCR. RESULTS: On pathological examination, SOS-related findings were observed in zone 3 in the placebo group; however, these were significantly suppressed in the BPS group. SE-1 staining showed a consistent number of LSECs in the BPS group compared with that in the placebo group, while CD42b staining showed a significant decrease in the number of extravasated platelet aggregation (EPA) in the BPS group. PAI-1 expression was significantly lower in the BPS group than in the placebo group; however, eNOS expression was significantly higher in the BPS group than in the placebo group. CONCLUSION: Prophylactic administration of BPS is useful for suppressing the development of SOS through the protective effects of LSEC.

NRF2 activates growth factor genes and downstream AKT signaling to induce mouse and human hepatomegaly.

BACKGROUND & AIMS: Hepatomegaly can be triggered by insulin and insulin-unrelated etiologies. Insulin acts via AKT, but how other challenges cause hepatomegaly is unknown. METHODS: Since many hepatomegaly-inducing toxicants and stressors activate NRF2, we examined the effect of NRF2 activation on liver size and metabolism using a conditional allele encoding a constitutively active NRF2 variant to generate Nrf2Act-hep mice in which NRF2 is selectively activated in hepatocytes. We also used adenoviruses encoding variants of the autophagy adaptor p62/SQSTM1, which activates liver NRF2, as well as liver-specific ATG7-deficient mice (Atg7Δhep) and liver specimens from patients with hepatic sinusoidal obstruction syndrome (HSOS) and autoimmune hepatitis (AIH). RNA sequencing and cell signaling analyses were used to determine cellular consequences of NRF2 activation and diverse histological analyses were used to study effects of the different manipulations on liver and systemic pathophysiology. RESULTS: Hepatocyte-specific NRF2 activation, due to p62 accumulation or inhibition of KEAP1 binding, led to hepatomegaly associated with enhanced glycogenosis, steatosis and G2/M cell cycle arrest, fostering hyperplasia without cell division. Surprisingly, all manipulations that led to NRF2 activation also activated AKT, whose inhibition blocked NRF2-induced hepatomegaly and glycogenosis, but not NRF2-dependent antioxidant gene induction. AKT activation was linked to NRF2-mediated transcriptional induction of PDGF and EGF receptor ligands that signaled through their cognate receptors in an autocrine manner. Insulin and insulin-like growth factors were not involved. The NRF2-AKT signaling axis was also activated in human HSOS- and AIH-related hepatomegaly. CONCLUSIONS: NRF2, a transcription factor readily activated by xenobiotics, oxidative stress and autophagy disruptors, may be a common mediator of hepatomegaly; its effects on hepatic metabolism can be reversed by AKT/tyrosine kinase inhibitors. LAY SUMMARY: Hepatomegaly can be triggered by numerous etiological factors, including infections, liver cancer, metabolic disturbances, toxicant exposure, as well as alcohol abuse or drug-induced hepatitis. This study identified the oxidative stress response transcription factor NRF2 as a common mediator of hepatomegaly. NRF2 activation results in elevated expression of several growth factors. These growth factors are made by hepatocytes and activate their receptors in an autocrine fashion to stimulate the accumulation of glycogen and lipids that lead to hepatocyte and liver enlargement. The protein kinase AKT plays a key role in this process and its inhibition leads to reversal of hepatomegaly.

Liquiritigenin and liquiritin alleviated monocrotaline-induced hepatic sinusoidal obstruction syndrome via inhibiting HSP60-induced inflammatory injury.

Hepatic sinusoidal obstruction syndrome (HSOS) is a life-threatening liver disease caused by the damage to liver sinusoidal endothelial cells (LSECs). Liquiritigenin and liquiritin are two main compounds in Glycyrrhizae Radix et Rhizoma (Gan-cao). Our previous study has shown that both liquiritigenin and liquiritin alleviated monocrotaline (MCT)-induced HSOS in rats via inducing the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant signaling pathway. This study aims to further investigate whether inhibiting liver inflammatory injury also contributed to the liquiritigenin and liquiritin-provided alleviation on MCT-induced HSOS. The results of serum alanine/aspartate aminotransferases (ALT/AST) activities and total bilirubin (TBil) amount, liver histological evaluation, scanning electron microscope observation and hepatic metalloproteinase-9 (MMP9) expression showed that liquiritigenin and liquiritin both alleviated MCT-induced HSOS in rats. Liquiritigenin and liquiritin reduced the increased liver myeloperoxidase (MPO) activity, mRNA expression of pro-inflammatory factors, hepatic infiltration of immune cells, hepatic toll-like receptor 4 (TLR4) expression and nuclear factor κB (NFκB) nuclear accumulation induced by MCT in rats. Furthermore, liquiritigenin and liquiritin attenuated MCT-induced liver mitochondrial injury, increased the decreased Lon protein expression and reduced the release of heat shock protein 60 (HSP60). Moreover, liquiritigenin and liquiritin also reduced NFκB nuclear accumulation and decreased the elevated cellular mRNA expression of NFκB-downstream pro-inflammatory cytokines induced by HSP60 in macrophage RAW264.7 cells. In conclusion, our study revealed that both liquiritigenin and liquiritin alleviated MCT-induced HSOS by inhibiting hepatic inflammatory responses triggered by HSP60.

Liver Inflammatory Injury Initiated by DAMPs-TLR4-MyD88/TRIF-NFκB Signaling Pathway Is Involved in Monocrotaline-Induced HSOS.

Hepatic sinusoidal obstruction syndrome (HSOS) causes considerable morbidity and mortality in clinic. Up to now, the molecular mechanisms involved in the development of HSOS still remain unclear. Here, we report that hepatic inflammation initiated by damage-associated molecular patterns (DAMPs) plays a critical role in the development of HSOS. Monocrotaline (MCT) belongs to pyrrolizidine alkaloids. Monocrotaline-induced HSOS in mice and rats was evidenced by the increased serum alanine/aspartate aminotransferase (ALT/AST) activities, the elevated hepatic metalloproteinase 9 (MMP9) expression, and results from liver histological evaluation and scanning electron microscope observation. However, MCT-induced HSOS was markedly attenuated in myeloid differentiation primary response gene 88 (MyD88), TIR-domain-containing adapter-inducing interferon-ß (TRIF) and toll like receptor 4 (TLR4) knock-out mice. Monocrotaline increased liver myeloperoxidase activity, serum contents of proinflammatory cytokines, hepatic aggregation of immune cells, and nuclear accumulation of nuclear factor κB (NFκB). However, these inflammatory responses induced by MCT were all diminished in MyD88, TRIF, and TLR4 knock-out mice. Monocrotaline elevated serum contents of DAMPs including high mobility group box 1 (HMGB1) and heat shock protein 60 (HSP60) both in mice and in rats. HSOS was markedly exacerbated and serum contents of HMGB1 and HSP60 were elevated in nuclear factor erythroid 2-related factor 2 (Nrf2) knock-out mice treated with MCT. Our findings indicate that hepatic inflammatory injury mediated by DAMPs-initiated TLR4-MyD88/TRIF-NFκB inflammatory signal pathway plays an important role in HSOS development.

(-)-Epicatechin attenuates hepatic sinusoidal obstruction syndrome by inhibiting liver oxidative and inflammatory injury.

Hepatic sinusoidal obstruction syndrome (HSOS) is a rare liver disease with considerable morbidity and mortality. (-)-Epicatechin (EPI) is a natural flavonol. This study aims to investigate the protection of EPI against monocrotaline (MCT)-induced HSOS and its engaged mechanism. Results of serum alanine/aspartate aminotransferases (ALT/AST) activities, total bilirubin (TBil) and bile acids (TBA) amounts, liver histological evaluation, scanning electron microscope observation and hepatic metalloproteinase-9 (MMP-9) expression all demonstrated the protection by EPI against MCT-induced HSOS in rats. EPI attenuated liver oxidative injury induced by MCT. EPI enhanced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and increased the expression of its downstream antioxidant genes in rats. Molecular docking results implied the potential interaction of EPI with the Nrf2 binding site in kelch-like ECH-associated protein-1 (Keap1). The EPI-provided protection against MCT-induced HSOS was diminished in Nrf2 knock-out mice when mice were treated with MCT for 24 h but not for 48 h. However, EPI reduced the increased liver myeloperoxidase (MPO) activity, hepatic infiltration of immune cells, pro-inflammatory cytokines expression and nuclear factor κB (NFκB) activation in both wild-type and Nrf2 knock-out mice when mice were treated with MCT for 48 h. EPI reduced the elevated serum heat shock protein 60 (HSP60) content, and reversed the decreased mitochondria expression of HSP60 and Lon in livers from MCT-treated rats. Furthermore, the MCT-induced HSOS was markedly alleviated in mice treated with anti-HSP60 antibody. Taken together, this study demonstrates that EPI attenuates MCT-induced HSOS by reducing liver oxidative injury via activating Nrf2 antioxidant pathway and inhibiting liver inflammatory injury through abrogating NFκB signaling pathway initiated by HSP60.

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.

Venoocclusive disease due to chemotherapy for pediatric acute lymphoblastic leukemia is associated with increased levels of plasminogen-activator inhibitor-1.

We describe three cases of sinusoidal obstruction syndrome/venoocclusive disease (SOS) in pediatric patients with acute lymphoblastic leukemia (ALL). All three episodes occurred during or just after the induction or reinduction phase of treatment based on prednisone/dexamethasone, vincristine, daunorubicin, and pegylated-l-asparaginase. SOS episodes were categorized as mild/moderate and resolved in 7, 10, and 16 days using supportive measures or defibrotide therapy. In all three episodes, the clinical diagnosis of SOS was associated with a significant increase in plasminogen-activator inhibitor-1 (PAI-1) that reduced with patient clinical improvement. PAI-1 warrants study as a diagnostic marker for SOS in ALL.

Evaluation of the therapeutic effects of rice husk nanosilica combined with platelet-derived growth factor in hepatic veno-occlusive disease.

Veno-occlusive disease is an important pattern of hepatotoxicity associated with antineoplastic drugs. The study investigated the possible therapeutic effects of RHS nanoparticles combined with a PDGF on veno-occlusive disease (VOD) in liver elicited in rats with DAC. In this work, nanosilica (SiO2) was successfully prepared from rice husk, and its physicochemical characteristics were investigated using EDX, XRD, N2 adsorption-desorption isotherm, SEM, and TEM. Forty-eight male Sprague-Dawely rats were distributed into 6 groups, with 8 rats in each. The first group served as the control. In the second group, animals were infused with DAC (0.015 mg/kg; 1-3 days) by intraperitoneal injection (i.p.). In the third group, rats were injected i.p. with DAC, and then at 24 h following the last dose of DAC, received nano-RHS incorporated with PDGF twice a week for 4 weeks. In the fourth group, normal animals were injected with RHS. In the fifth group, normal rats received PDGF, and in the sixth group, normal rats received nano-RHS combined with PDGF. The prepared nanosilica showed type II adsorption isotherm characteristic for mesoporous materials with a specific surface area of 236 m2/g. TEM imaging confirmed the production of nanoparticles via the followed preparation procedure. Radical scavenging potential for nano-RHS was determined using two different in-vitro assays: DPPH, and ABTS radicals. The results of this work show that administration of nano-RHS combined with PDGF significantly reversed the oxidative stress effects of DAC as evidenced by a decrease in liver function. It can be concluded that the nano-RHS combined with PDGF is useful in preventing oxidative stress and hepatic VOD induced by chemotherapy such as DAC.

Defibrotide: An Oligonucleotide for Sinusoidal Obstruction Syndrome.

OBJECTIVE: To review the efficacy and safety of defibrotide as well as its pharmacology, mechanism of action, pharmacokinetics (PK), drug-drug interactions, dosing, cost considerations, and place in therapy. DATA SOURCES: A PubMed search was performed through August 2017 using the terms defibrotide, oligonucleotide, hepatic veno-occlusive disease (VOD), sinusoidal obstruction syndrome (SOS), and hematopoietic cell transplantation (HCT). Other data sources were from references of identified studies, review articles, and conference abstracts plus manufacturer product labeling and website, the Food and Drug Administration website, and clinicaltrials.gov. STUDY SELECTION AND DATA EXTRACTION: English-language trials that examined defibrotide's pharmacodynamics, mechanism, PK, efficacy, safety, dosing, and cost-effectiveness were included. DATA SYNTHESIS: Trials have confirmed the safety and efficacy of defibrotide for treatment of VOD/SOS in adult and pediatric HCT patients, with complete response rates and day +100 overall survival rates ranging from 25.5% to 76% and 35% to 64%, respectively. The British Committee for Standards in Haematology/British Society for Blood and Marrow Transplantation Guidelines recommend defibrotide prophylaxis in pediatric and adult HCT patients with risk factors for VOD/SOS; however, its prophylactic use in the United States is controversial. Although there are efficacy data to support this strategy, cost-effectiveness data have not shown it to be cost-effective. Defibrotide has manageable toxicities, with low rates of grade 3 to 4 adverse effects. CONCLUSIONS: Defibrotide is the first medication approved in the United States for the treatment of adults and children with hepatic VOD/SOS, with renal or pulmonary dysfunction following HCT. Data evaluating defibrotide for VOD/SOS prevention are conflicting and have not shown cost-effectiveness.

Phosphodiesterase III inhibitor attenuates rat sinusoidal obstruction syndrome through inhibition of platelet aggregation in Disse's space.

BACKGROUND AND AIM: Sinusoidal obstruction syndrome (SOS) is a serious drug-induced liver injury. However, the pathophysiology of the disease remains unclear. This study investigated the effects of cilostazol (CZ), a phosphodiesterase III inhibitor, in a monocrotaline (MCT)-induced rat model of SOS. METHODS: Male Wistar rats were administrated MCT to induce SOS. Rats were divided into control, MCT, and MCT + CZ groups. In the MCT + CZ group, CZ was administered at 48 h, 24 h, and 30 min prior to and 8 h and 24 h after MCT administration. The MCT group was treated with water instead of CZ. At 48 h after MCT administration, blood and liver samples were collected to assess biochemistry and liver histology. Expression of rat endothelial cell antigen, CD34, CD41, P-selectin, and caspase-3 in the liver were analyzed. Plasminogen activator inhibitor-1 (PAI-1) in hepatocytes was analyzed using western blotting and polymerase chain reaction. RESULTS: In the MCT group, macroscopic findings showed a dark-red liver surface. Histological findings showed sinusoidal dilatation, coagulative necrosis of hepatocytes, and endothelial damage of the central vein. These changes were attenuated in the MCT + CZ group. Elevated serum transaminase and decreased platelet counts were observed in the MCT + CZ group compared with those in the MCT group. Treatment with CZ reduced MCT-induced damage to the liver sinusoidal endothelial cells, inhibited extravasated platelet aggregation, and suppressed hepatocyte apoptosis around the central vein. CZ attenuated hepatic PAI-1 protein and mRNA levels. CONCLUSIONS: Cilostazol attenuated MCT-induced SOS by preventing damage to liver sinusoidal endothelial cells and extravasated platelet aggregation. Hepatic PAI-1 levels were suppressed with CZ treatment.

Detection of Sp110 by Flow Cytometry and Application to Screening Patients for Veno-occlusive Disease with Immunodeficiency.

Mutations in Sp110 are the underlying cause of veno-occlusive disease with immunodeficiency (VODI), a combined immunodeficiency that is difficult to treat and often fatal. Because early treatment is critically important for patients with VODI, broadly usable diagnostic tools are needed to detect Sp110 protein deficiency. Several factors make establishing the diagnosis of VODI challenging: (1) Current screening strategies to identify severe combined immunodeficiency are based on measuring T cell receptor excision circles (TREC). This approach will fail to identify VODI patients because the disease is not associated with severe T cell lymphopenia at birth; (2) the SP110 gene contains 17 exons, making it a challenge for Sanger sequencing. The recently developed next-generation sequencing (NGS) platforms that can rapidly determine the sequence of all 17 exons are available in only a few laboratories; (3) there is no standard functional assay to test for the effects of novel mutations in Sp110; and (4) it has been difficult to use flow cytometry to identify patients who lack Sp110 because of the low level of Sp110 protein in peripheral blood lymphocytes. We report here a novel flow cytometric assay that is easily performed in diagnostic laboratories and might thus become a standard assay for the evaluation of patients who may have VODI. In addition, the assay will facilitate investigations directed at understanding the function of Sp110.