Transforming growth factor beta-1 released from platelets contributes to hypercoagulability in veno-occlusive disease following hematopoetic stem cell transplantation

Effects of clopidogrel bisulfate on B16-F10 cells and tumor development in a murine model of melanoma

Metastatic melanoma is a very aggressive skin cancer. Platelets are constituents of the tumor microenvironment and, when activated, contribute to cancer progression, especially metastasis and inflammation. P2Y12 is an adenosine diphosphate receptor that triggers platelet activation. Inhibition of P2Y12 by clopidogrel bisulfate (CB) decreases platelet activation, which is also controlled by the extracellular concentration and the metabolism of purines by purinergic enzymes. We evaluated the effects of CB on the viability and proliferation of cultured B16-F10 cells. We also used a metastatic melanoma model with C57BL-6 mice to evaluate cancer development and purine metabolism modulation in platelets. B16-F10 cells were administered intraperitoneally to the mice. Two days later, the animals underwent a 12-day treatment with CB (30 mg/kg by gavage). We have found that CB reduced cell viability and proliferation in B16-F10 culture in 72 h at concentrations above 30 µm. In vivo, CB decreased tumor nodule counts and lactate dehydrogenase levels and increased platelet purine metabolism. Our results showed that CB has significant effects on melanoma progression.

Correlation of chemokines and growth factors with radiation-induced liver injury after interstitial high dose rate (HDR) brachytherapy of liver metastases

Background

Locoregional therapies, as imaging-guided tumor-directed procedures, are emerging treatment strategies in the management of primary and secondary liver malignancies such as e.g. colorectal cancer liver metastases. As one of those, irradiation-based interstitial high dose rate brachytherapy (iBT) of liver metastases bears a risk of developing focal radiation-induced liver injury (fRILI). Since little is known about biological factors involved in hepatic dysfunction after irradiation, the aim of this study was to identify factors, that may play a role in the underlying mechanism of fRILI, and that potentially may serve as biomarkers for post-therapeutic fRILI to improve specific management and treatment of patients.

Methods

Twenty-two patients with hepatic malignancies (tumor patients, TP) underwent iBT with total ablative doses of radiation to the target volume ranging from e.g. 15 to 25 Gy. Hepatobiliary magnetic resonance imaging (MRI) was performed 6 weeks after iBT to quanitify fRILI. Blood samples were taken before (pre) and 6 weeks after (post) iBT from TP, and from ten healthy volunteers (HV controls) for the analyses of humoral mediators: monocyte chemoattractant protein-1 (MCP-1), chemokine (C-X3-C motif) ligand 1 (CX3CL1), vascular endothelial growth factor (VEGF) and beta-nerve growth factor (beta-NGF) using the Multi-Analyte Flow Assay via flow cytometry. Correlation analyses between the humoral mediators (pre and post iBT) with the tumor volume and fRILI were performed.

Results

While MCP-1 and CX3CL1 tended to decrease in TP vs. HV, VEGF was significantly decreased in TP vs. HV pre and post iBT (p < 0.05). Beta-NGF levels were significantly increased in TP vs. HV pre and post iBT (p < 0.05). Baseline circulating levels of MCP-1, VEGF and beta-NGF have shown significant positive correlations with the hepatic tumor volume (p < 0.05). Circulating levels of humoral mediators before treatment did not correlate with fRILI, while CX3CL1 and VEGF after iBT have shown significant positive correlations with fRILI (p < 0.05).

Conclusion

Tumor volume and threshold dose of irradiation damage correlated positively with MCP-1 and VEGF as well as NGF and CX3CL, respectively. Thus, investigation of biological mediators in blood samples from tumor patients may provide an appropriate tool to predict fRILI after interstitial HDR brachytherapy of liver metastases.

Regulation of TNF-Induced Osteoclast Differentiation

Increased osteoclast (OC) differentiation and activity is the critical event that results in bone loss and joint destruction in common pathological bone conditions, such as osteoporosis and rheumatoid arthritis (RA). RANKL and its decoy receptor, osteoprotegerin (OPG), control OC differentiation and activity. However, there is a specific concern of a rebound effect of denosumab discontinuation in treating osteoporosis. TNFα can induce OC differentiation that is independent of the RANKL/RANK system. In this review, we discuss the factors that negatively and positively regulate TNFα induction of OC formation, and the mechanisms involved to inform the design of new anti-resorptive agents for the treatment of bone conditions with enhanced OC formation. Similar to, and being independent of, RANKL, TNFα recruits TNF receptor-associated factors (TRAFs) to sequentially activate transcriptional factors NF-κB p50 and p52, followed by c-Fos, and then NFATc1 to induce OC differentiation. However, induction of OC formation by TNFα alone is very limited, since it also induces many inhibitory proteins, such as TRAF3, p100, IRF8, and RBP-j. TNFα induction of OC differentiation is, however, versatile, and Interleukin-1 or TGFβ1 can enhance TNFα-induced OC formation through a mechanism which is independent of RANKL, TRAF6, and/or NF-κB. However, TNFα polarized macrophages also produce anabolic factors, including insulin such as 6 peptide and Jagged1, to slow down bone loss in the pathological conditions. Thus, the development of novel approaches targeting TNFα signaling should focus on its downstream molecules that do not affect its anabolic effect.

RANKL cytokine enhances TNF-induced osteoclastogenesis independently of TNF receptor associated factor (TRAF) 6 by degrading TRAF3 in osteoclast precursors

Cytokines, including receptor activator of nuclear factor κB ligand (RANKL) and TNF, induce increased osteoclast (OC) formation and bone loss in postmenopausal osteoporosis and inflammatory arthritides. RANKL and TNF can independently induce OC formation in vitro from WT OC precursors via TNF receptor-associated factor (TRAF) adaptor proteins, which bind to their receptors. Of these, only TRAF6 is required for RANKL-induced osteoclastogenesis in vitro However, the molecular mechanisms involved remain incompletely understood. Here we report that RANKL induced the formation of bone-resorbing OCs from TRAF6^-/- OC precursors when cultured on bone slices but not on plastic. The mechanisms involved increased TNF production by TRAF6^-/- OC precursors resulting from their interaction with bone matrix and release of active TGFβ from the resorbed bone, coupled with RANKL-induced autophagolysosomal degradation of TRAF3, a known inhibitor of OC formation. Consistent with these findings, RANKL enhanced TNF-induced OC formation from TRAF6^-/- OC precursors. Moreover, TNF induced significantly more OCs from mice with TRAF3 conditionally deleted in myeloid lineage cells, and it did not inhibit RANKL-induced OC formation from these cells. TRAF6^-/- OC precursors that overexpressed TRAF3 or were treated with the autophagolysosome inhibitor chloroquine formed significantly fewer OCs in response to TNF alone or in combination with RANKL. We conclude that RANKL can enhance TNF-induced OC formation independently of TRAF6 by degrading TRAF3. These findings suggest that preventing TRAF3 degradation with drugs like chloroquine could reduce excessive OC formation in diseases in which bone resorption is increased in response to elevated production of these cytokines.

Mechanism of the protective effects of the combined treatment with rhynchophylla total alkaloids and sinapine thiocyanate against a prothrombotic state caused by vascular endothelial cell inflammatory damage

The aim of the present study was to investigate the effect and the underlying mechanism of the combined treatment of rhynchophylla total alkaloids (RTA) and sinapine thiocyanate for protection against a prothrombotic state (PTS) associated with the tumor necrosis factor-alpha (TNF-α)-induced inflammatory injury of vascular endothelial cells (VECs). A TNF-α-induced VEC inflammatory injury model was established, and cell morphology of VECs was evaluated using scanning electron microscopy. In addition, reverse transcription-quantitative polymerase chain reaction and western blot analysis were performed to examine the mRNA and protein expression of coagulation-related factors, including nuclear factor-κB (NF-κB), transforming growth factor-β1 (TGF-β1), tissue factor (TF), plasminogen activator inhibitor (PAI-1), protease-activation receptors (PAR-1) and protein kinase C (PKC-α) in VECs. Combined treatment with RTA and sinapine thiocyanate was demonstrated to reduce, to a varying extent, the mRNA and protein expression of NF-κB, TGF-β1, TF, PAR-1, PKC-α and PAI-1. Furthermore, combined treatment with RTA and sinapine thiocyanate was able to downregulate the expression of coagulation-related factors in injured VECs, thereby inhibiting the PTS induced by vascular endothelial injury. The underlying mechanism is partially associated with the TF-mediated activation of the thrombin-receptor signaling pathway that suppresses coagulation during inflammation and balances fibrinolysis in order to inhibit fibrin generation and deposition.

Extravasated platelet aggregation in liver zone 3 may correlate with the progression of sinusoidal obstruction syndrome following living donor liver transplantation: A case report

Sinusoidal obstruction syndrome (SOS), previously known as veno-occlusive disease, is relatively rare subsequent to liver transplantation (LT). SOS refractory to medical therapy, however, can result in centrilobular fibrosis, portal hypertension and liver failure. Although sinusoidal endothelial cell damage around central venules (zone 3) occurs early in the development of SOS, the detailed mechanism of SOS development and its association with thrombocytopenia are not yet completely understood. The present report describes a patient who experienced SOS with unexplained thrombocytopenia following living donor LT. The progression of SOS resulted in graft dysfunction and the patient succumbed. The presence of platelets in the liver allograft was assayed immunohistochemically using antibody to the platelet marker cluster of differentiation 42b (platelet glycoprotein Ib). Platelet aggregates were found attached to hepatocytes along the sinusoid and within the cytoplasm of hepatocytes, particularly in zone 3. By contrast, no staining was observed in zone 1. These findings suggested that extravasated platelet aggregation in the space of Disse and the phagocytosis of platelets by hepatocytes were initiated by sinusoidal endothelial cell damage due to the toxicity of the immunosuppressant tacrolimus or a corticosteroid pulse, and that platelet activation and degranulation may be at least partially involved in the mechanism responsible for SOS.

A murine model of hepatic veno-occlusive disease induced by allogeneic hematopoietic stem cell transplantation

Hepatic veno-occlusive disease (HVOD) is a life-threatening complication of bone marrow stem cell transplantation. The understanding of this clinical condition is hampered by the lack of suitable animal models. Here, we present a murine (BALB/c-based) model of HVOD induced by allogeneic hematopoietic stem cell transplantation (allo-HSCT). The chimerism rate of bone marrow was measured on days 5 and 10, while the chimerism rate of peripheral blood was measured on day 15 after allo-HSCT. Percentages of peripheral reticulocytes and serum levels of bilirubin and alanine aminotransferase (as liver function tests) were measured on days 5, 10, 15, 20, and 30. Livers were obtained on days 5, 10, 15, 20, and 30, and fixed in formaldehyde or glutaric dialdehyde. Liver slices were processed using the hematoxylin-eosin, Masson's trichrome, or immunohistochemistry staining, and examined by light or transmission electron microscopy. Sinusoidal damages were the earliest pathological changes occurring in the allo-HSCT-induced HVOD, followed by coagulative necrosis of liver cells. The liver cell necrosis was later attenuated and sinusoidal endothelial cell morphology improved. However, on day 30, the edema and necrosis of liver cells became aggravated again. Furthermore, sinusoidal lining cell regeneration and partly attenuated liver cell necrosis were followed by the moderate to severe central vein fibrosis. In conclusion, we have successfully established a murine model of HSCT-HVOD. This model develops moderate to severe HVOD which cannot heal without intervention.

Cytokine and chemokine patterns across 100 days after hematopoietic stem cell transplantation in children

We mapped the cytokine response to hematopoietic stem cell transplantation (HSCT) by assaying 51 cytokines and chemokines each week for 100 days in 51 children receiving allogeneic (n = 44) or autologous HSCT (n = 7). Assay values were reported as mean fluorescence intensity (MFI). Log transformation converted MFI to clinically relevant measures (ie, pg/mL). We searched for potential markers of transplant complications by using mixed treatment by subject analysis of variance. Global cytokine secretion in HSCT recipients was significantly lower than in concurrent control patients (n = 11). Coincident with the nadir in WBC count, the concentration of many cytokines declined further by the second and third week. All analytes (except monokine induced by gamma interferon [MIG]) subsequently rebounded by week 4 (coincident with engraftment and recovery of WBC count) but often still remained well below control levels. Concurrent with the collective nadir of multiple cytokines, monocyte chemoattractant protein 1 (MCP-1), growth-regulated oncogene alpha (GRO-a), and leptin surged during weeks 2 to 4. High levels of leptin persisted throughout the 100 post-transplant days. Also during weeks 2 to 4, hepatocyte growth factor (HGF) and IL-6 surged in children with complications but not in those without complications. The peak in HGF was more pronounced in veno-occlusive disease (VOD). HGF and IL-6 secretion rose at least 2 weeks before the clinical diagnosis of VOD or graft-versus-host disease (GVHD). From week 4 onward in all groups, the MFI of the cytokine resistin increased to 5 to 15 times above concurrent control. HGF has now emerged in 3 or more biomarker discovery efforts for GVHD (and in our population for VOD as well). HGF (with or without IL-6) should be investigated as a potential predictive biomarker of VOD or GVHD. Alternatively, the hyperinflammatory "signature" provided by a multicytokine assay may be predictive.

Behçet's disease: new insight into the relationship between procoagulant state, endothelial activation/damage and disease activity

BACKGROUND

Behçet disease (BD) is associated with a prothrombotic state of unknown origin that may lead to life-threatening events. Calibrated Automated Thrombogram (CAT) and Rotational Thromboelastometry (ROTEM) are two global haemostasis assays that may reveal new insights into the physiopathological mechanisms of the disease and its procoagulant condition.

METHODS

23 BD patients who had no signs or symptoms of current thrombosis and 33 age- and sex-matched controls were included in the study. We performed ROTEM and CAT tests and assessed erythrocyte count, platelet count, platelet contribution to clot formation and plasma levels of tissue-type plasminogen activator, plasminogen activator inhibitor type 1 (PAI-1), fibrinogen, C-reactive protein (CRP), thrombin-antithrombin III complex (TAT), D-dimer and E-selectin (ES).

RESULTS

Both ROTEM and CAT tests showed a hypercoagulable state in the BD patients. Plasma levels of PAI-1, fibrinogen, TAT, CRP and ES were significantly increased in this group compared to controls. The disease activity (DA) was significantly correlated with levels of ES and the maximum clot firmness, and this last one, in turn, correlated with rising levels of ES, PAI-1, CRP and fibrinogen. CAT parameters did not correlate with DA or ES.

CONCLUSIONS

Both ROTEM and CAT tests reveal that patients with BD have a procoagulant state even in the absence of thrombosis. ROTEM test indicates that increased levels of fibrinogen and PAI-1 may be involved in the prothrombotic state of this pathology, while platelets do not significantly contribute. Moreover, CAT assay demonstrate that plasma from BD patients is able to generate more thrombin than controls in response to the same stimulus and that this effect is independent of the DA and the endothelial impairment suggesting the involvement of another factor in the hypercoagulable state observed in BD patients. This study also shows that endothelium activation/damage may be a contributing factor in both the procoagulant and clinical conditions of BD, as shown by the direct correlation between ES levels, ROTEM parameters and DA.

Defibrotide for the treatment of hepatic veno-occlusive disease in children after hematopoietic stem cell transplantation

Hepatic veno-occlusive disease (VOD) is a serious complication of stem cell transplantation in children. VOD is characterized by rapid weight gain, hepatomegaly, hyperbilirubinemia and ascites. The pathogenesis of VOD is thought to involve chemotherapy and radiation-induced damage to the sinusoidal endothelium, resulting in endothelial injury, microthrombosis, subendothelial damage and cytokine activation. These processes lead to concomitant progressive hepatocellular dysfunction and subsequent fluid retention and renal impairment. Severe VOD is typically associated with multiorgan failure and high mortality. A number of possible strategies for the prevention and/or treatment of VOD in children have been investigated. The most promising agent to date is defibrotide, a novel polydeoxyribonucleotide with fibrinolytic properties but no major bleeding risk. Numerous studies, including Phase II/III trials, have shown clinical benefit in pediatric patients with the use of defibrotide treatment and prophylaxis. This review discusses VOD in children and focuses on therapeutic options, including defibrotide, in this patient population.

Significance of circulating endothelial progenitor cells in patients with fracture healing process

Fracture healing is a complex bone formation process, and neovascularization may contribute to new bone regeneration. The circulating endothelial progenitor cell (EPC) mobilization and homing could involve in neovascularization and vasculogenesis. In this study, we investigate the changes of circulating EPC during bone fracture healing, and the possible contribution of EPCs to increased neovascularization and fracture healing. The number of circulating EPCs was monitored in twenty-four patients with long bone traumatic fracture within the first 48 h and at 3, 5, 10, and 14 days post-fracture. The mononuclear cells which isolated from peripheral blood were analyzed by flow cytometry. Peripheral blood counts of leukocytes and platelets were measured by hematology analyzer. The amount of peripheral EPCs significantly increased in patients with fracture compared to age-matched healthy control subjects within the first 48 h after injury, and peaked at 3 days post-fracture. There was no significant difference in the change trend of early EPCs between male and female, but the number of early EPCs was significantly greater in younger patients compared to older patients. A comparison of the EPCs levels between patients with severe injury (ISS > 16) and patients with mild injury (ISS ≤ 16) revealed no statistically significant difference. The level of early EPCs was inverse correlation with the level of plate after fracture, but no correlation with the level of peripheral leucocytes. These findings suggest traumatic fracture may induce the mobilization of EPCs into the peripheral circulation. The increased EPCs may contribute to neovascularization and involve in fracture healing.

Antineoplastic agent busulfan regulates a network of genes related to coagulation and fibrinolysis

Purpose Hepatic veno-occlusive disease (HVOD) is one of the major complications following hematopoietic stem cell transplantation (HSCT). Although high-dose busulfan is associated with the development of HVOD, the underlying molecular mechanisms are still unknown.Methods Transcriptional gene regulation by busulfan was profiled using Affymetrix GeneChip® Human Genome U133 Plus 2.0 arrays. Messenger RNA (mRNA) expression of regulated genes was assessed by TaqMan real-time polymerase chain reaction (PCR), and protein expression and secretion was determined by enzyme-linked immunosorbent assay (ELISA)in cell supernatants, lysates, and patient plasma.Results Plasma levels of plasminogen activator inhibitor(PAI)-1 significantly increased 48 h after starting busulfan treatment IV in children preconditioned for HSCT. In vitro,busulfan significantly induced plasminogen activator inhibitor-1 (PAI-1) expression in endothelium-like ECV304 cells in a concentration- and time-dependent manner. Comparative transcriptional profiling of busulfan-treated and control ECV304 cells identified differential expression of genes related to coagulation and fibrinolysis, including tissue factor, tissue factor pathway inhibitor-1, protein S, thrombospondin-1, urokinase receptor, and PAI-1, as well as activin A and transforming growth factor beta 1 (TGF-β1). Ingenuity pathway analysis (IPA) suggested TGF-β1 as a central modulator of gene regulation by busulfan. Consequently, expression of tissue factor, urokinase receptor, and PAI-1 mRNA and PAI-1 protein secretion induced by busulfan were significantly reduced by the activin A/TGF-β1 inhibitor SB 431542 in ECV304 and primary endothelial cells.Conclusions This is the first report that directly relates busulfan exposure to antifibrinolytic activity by PAI-1 and hypercoagulation possibly mediated by members of the TGF-β1 family. This suggests further research to evaluate activin A and TGF-β1 as potential targets for HVOD treatment.

Thrombosis in stem cell transplantation

Hemostatic changes and thrombotic events are frequent in patients undergoing stem cell transplantation. Arterial and venous thromboses are major causes of morbidity and mortality. Thrombotic complications can be classified into four groups including: catheter-related thrombosis, venous thromboembolic (VTE) events, sinusoidal obstructive syndrome (SOS)/veno-occlusive disease, and transplant-associated thrombotic microangiopathy (TAM). The incidence of catheter-related thrombosis is 8-20% in patients undergoing autologous hematopoietic stem cell transplantation (HSCT), and the incidence is low in syngeneic and allogeneic transplant patients. Venous duplex Doppler ultrasound, venogram, and computed tomography scan are required to visualize the venous thrombus. The treatment should be aimed at the prevention of pulmonary embolism, the avoidance of thrombus extension, and the preservation of catheter patency. Patients undergoing HSCT may have risk factors for VTE including underlying malignancy, traumatic brain injury, prolonged hospitalization, administration of conditioning regimens, and central venous catheters. Important risk factors are presence of history of VTE and graft-versus-host disease. One-year incidence of symptomatic VTE is 3.7%. SOS, also known as veno-occlusive disease, is a serious liver disease, seen in approximately 50-60% of HSCT patients. The mortality rate from the severe form of SOS is 84.3% and majority of the patients have multi-organ failure. The frequency is quite low after autologous transplantation. Risk factors for SOS include pre-existing hepatic damage, previous high-dose chemotherapy and abdominal irradiation, female gender and donor-recipient human leukocyte antigen disparity. Cyclophosphamide and busulphan are the most common agents with the highest incidence and fatal SOS. Histopathologic features of SOS include dilatation of sinusoids, necrosis of perivenular hepatocytes, and obstruction of small intrahepatic central venules by microthrombi and fibrin deposition. Signs of SOS usually occur within first 30 days after HSCT including hyperbilirubinemia, hepatomegaly, ascites, and weight gain. Symptoms of liver failure, including encephalopathy, coagulopathy, and renal failure will appear in severe form. A hepatic venous pressure gradient above 10 mmHg is highly specific for SOS. Early use of defibrotide has been shown to be effective in the treatment of high-risk SOS. TAM is a distinct, infrequent, and significant life-threatening complication of HSCT. TAM is seen in the range of 0·5-76% and was reported to be 10-25% in patients undergoing allogeneic HSCT with a mortality rate around 50%. It can also be seen after autologous HSCT and mainly affects the glomerular capillaries. There has been no standard therapy for TAM. Few case series reported good response to rituximab and high-dose corticosteroids were used with limited success. Trials with complement inhibitors such as eculizumab are currently underway.

Safety and efficacy of defibrotide for the treatment of severe hepatic veno-occlusive disease

Hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome, is a potentially life-threatening complication of chemotherapeutic conditioning used in preparation for hematopoietic stem-cell transplantation (SCT). VOD may occur in up to 62% of patients undergoing SCT, with onset generally within the first month after SCT. In severe cases, 100-day mortality is in excess of 80%. Current management consists of best supportive care, with no agents to date approved for treatment in the USA or the EU. Defibrotide, a polydisperse oligonucleotide, has been shown in phase II and III trials to improve complete response and survival in patients undergoing SCT with severe VOD. This article reviews our current understanding of VOD, and examines recent clinical findings on defibrotide for the treatment and prophylaxis of VOD.

Increase of plasminogen activator inhibitor-1 and decrease of transforming growth factor-b1 in children with dengue haemorrhagic fever in Indonesia

Mortality in children with severe dengue haemorrhagic fever (DHF) in Indonesia is high. The origin of the elevated plasminogen activator inhibitor-1 (PAI-1) levels in these children is unclear. We measured PAI-1, transforming growth factor-β1 (TGF-β1), platelet counts, plasma leakage and liver function in 71 children with DHF (3-15 years old) and in 30 healthy children. We found that PAI-1 concentrations in children with DHF were significantly higher on admission than on Day 2. Circulating TGF-β1 concentrations on admission were significantly lower in DHF than in controls, but on Day 2 increased towards levels in controls. TGF-β1 and PAI-1 concentrations were not correlated on either day. PAI-1 was correlated with platelet count and serum albumin on admission, and with degree of pleural effusion. Liver function tests were mildly elevated but not correlated with PAI-1. In conclusion, elevated PAI-1 concentrations in DHF were associated with platelet counts and plasma leakage.

Effect of prednisone on transforming growth factor-β1, connective tissue growth factor, nuclear factor-κBp65 and tumor necrosis factor-α expression in a murine model of hepatic sinusoidal obstruction syndrome induced by Gynura segetum

AIM

  One major cause of hepatic sinusoidal obstruction syndrome (HSOS) is the consumption of products containing pyrrolizidine alkaloids (PA). As the use of herbal preparations has increased in China, so has the number of reports of HSOS induced by ingesting PA-containing herbs. The aim of the present study was to investigate the mechanisms by which prednisone and the related factors, transforming growth factor (TGF)-β1 and connective tissue growth factor (CTGF), prevent liver fibrosis and the pathogenesis of HSOS.

METHODS

  A murine model of HSOS was created by oral gavage with Gynura segetum with or without prednisone for 30 days. Histological changes in liver tissue were evaluated by a scoring system in tissue slices subjected to hematoxylin-eosin and Masson trichrome staining. Hepatic expression of TGF-β1 and CTGF mRNA and protein was detected by immunohistochemistry, reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. RT-PCR was also used to detect tumor necrosis factor (TNF)-α and nuclear factor (NF)-κBp65 mRNA expression. Activation of NF-κBp65 was detected by immunohistochemistry.

RESULTS

  Intervention with prednisone diminished the symptoms of HSOS in mice treated with G. segetum. Prednisone treatment significantly inhibited expression of TGF-β1 and CTGF mRNA and protein (P < 0.05), and inhibited expression of TNF-α and NF-κBp65 mRNA (P < 0.05) in the liver tissue of HSOS mice.

CONCLUSION

  Prednisone suppresses the development of liver fibrosis in HSOS mice by inhibiting TGF-β1, CTGF, TNF-α and NF-κBp65 expression.

Effect of ligustrazine on mice model of hepatic veno-occlusive disease induced by Gynura segetum

BACKGROUND AND AIM

To investigate the therapeutic effect of ligustrazine on hepatic veno-occlusive disease (HVOD) induced by Gynura segetum and the possible mechanism of it.

METHODS

Female Kunming mice (115) were randomly divided into four groups, gavaged with 30 g/kg per day Gynura segetum (group A), 30 g/kg per day Gynura segetum + 100 mg/kg per day ligustrazine (group B), 30 g/kg per day Gynura segetum + 200 mg/kg per day ligustrazine (group C) or 30 mL/kg per day phosphate-buffered saline (PBS) (group D). Thirty days later, all of the mice were killed. Blood samples and livers were harvested. Histological changes were evaluated by light microscopy. Liver function was measured, and the expression of tissue factor (TF), early growth response factor-1 (Egr-1) and nuclear factor-KBp65 (NF-KBp65) were determined by reverse transcription-polymerase chain reaction and Western blot.

RESULTS

A total of 24 mice in group A developed HVOD. Compared with the controls, they had increased liver ratio, serum total bilirubin (TBIL), direct bilirubin (DBIL), transaminase and decreased albumin (ALB) (P < 0.05). Administration of ligustrazine improved the clinical signs and biochemistry parameters in a dose-dependent manner. Compared with group A, the expression of TF, Egr-1 and NF-KB p65 decreased in groups B and C (P < 0.05).

CONCLUSION

Ligustrazine has a therapeutic effect on HVOD, improving clinical manifestations and liver function. The possible mechanism may be that ligustrazine could reduce the expression of TF by downregulating the expression of transcription factors: Egr-1 and NF-KB p65.

Use of defibrotide in the treatment and prevention of veno-occlusive disease

Hepatic veno-occlusive disease (VOD) is one of the most important complications of high-dose chemotherapy and stem cell transplantation. VOD is a clinical syndrome characterized by jaundice, hepatic enlargement and fluid retention typically seen by day +30 after transplantation. Severe VOD is complicated by multiorgan failure and a high mortality rate approaching 100%. Defibrotide (DF) is a novel agent with both antithrombotic and fibrinolytic properties that has emerged as an effective therapy for severe VOD. In Phase II studies, treatment of severe VOD has resulted in complete responses of 30-60% and survival past day 100 ranging between 32-50%. A Phase III, historically controlled study of DF for treatment of severe VOD has recently been completed and results are awaited with interest. In addition, DF may be effective prophylaxis for VOD in high-risk patients. This review will focus on a summary of the pharmacology of DF and the clinical evidence for its use in VOD.

Hepatic veno-occlusive disease: a chemotherapy-related toxicity in children with malignancies

Hepatic veno-occlusive disease (VOD) is a major manifestation of liver toxicity associated with conventional and high-dose chemotherapy in children affected by hematologic malignancies and certain solid tumors. Clinically, patients present with jaundice, painful hepatomegaly, and fluid retention, which may evolve into multi-organ failure, a hallmark of severe disease. The pathogenesis is complex and not completely understood, but the damage to sinusoidal endothelium, typically caused by toxic metabolites released from antineoplastic drugs, is thought to play a crucial role, together with cytokine activation, immune deregulation, and coagulopathy. Diagnosis is based on clinical criteria supported by characteristic ultrasound findings, with the gold standard investigation being hepatic-venous pressure gradient measurement and biopsy. Several treatment options have been tested; the most convincing approach to date is the use of defibrotide, a novel oligonucleotide with antithrombotic and antiplatelet aggregating properties, as well as endothelial-stabilizing effects. This agent, together with other specific forms of supportive care, has shown efficacy in the treatment of established VOD and promising results in the prevention of VOD in pediatric patients receiving chemotherapy.

Emodin protects rat liver from CCl4-induced fibrogenesis via inhibition of hepatic stellate cells activation

AIM: To investigate the role of emodin in protecting the liver against fibrogenesis caused by carbon tetrachloride (CCl₄) in rats and to further explore the underlying mechanisms.

METHODS: Rat models of experimental hepatic fibrosis were established by injection with CCl₄; the treated rats received emodin via oral administration at a dosage of 20 mg/kg twice a week at the same time. Rats injected with olive oil served as a normal group. Histopathological changes were observed by hematoxylin and eosin staining. The activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum and hepatic hydroxyproline content were assayed by biochemical analyses. The mRNA and protein relevant to hepatic stellate cell (HSC) activation in the liver were assessed using real-time reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry, western blotting and enzyme-linked immunosorbent assay.

RESULTS: The degree of hepatic fibrosis increased markedly in the CCl₄ group compared to the normal group (P < 0.01), and decreased markedly in the emodin group compared to the CCl₄ group according to METAVIR scale (P < 0.01) compared with those in the normal control group (51.02 ± 10.64 IU/L and 132.28 ± 18.14 IU/L). The activities of serum ALT and AST were significantly higher in rats injected with CCl₄ (289.25 ± 68.84 IU/L and 423.89 ± 35.67 IU/L, both P < 0.05). The activities of serum ALT and AST were significantly reduced by administration of emodin (176.34 ± 47.29 IU/L and 226.1 ± 44.52 IU/L, both P < 0.05). Compared with the normal controls (54.53 ± 13.46 mg/g), hepatic hydroxyproline content was significantly higher in rats injected with CCl₄ (120.27 ± 28.47 mg/g, P < 0.05). Hepatic hydroxyproline content was significantly reduced in the rats treated with emodin at 20 mg/kg (71.25 ± 17.02 mg/g, P < 0.05). Emodin significantly protected the liver from injury by reducing serum AST and ALT activities and reducing hepatic hydroxyproline content. The mRNA levels of transforming growth factor-β1 (TGF-β1), Smad4 and α-SMA in liver tissues were significantly down-regulated in SD rats that received emodin treatment. Furthermore, significant down-regulation of serum TGF-β1 protein levels and protein expression of Smad4 and α-SMA in liver tissues was also observed in the rats. Emodin inhibited HSC activation by reducing the abundance of TGF-β1 and Smad4.

CONCLUSION: Emodin protects the rat liver from CCl₄-induced fibrogenesis by inhibiting HSC activation. Emodin might be a therapeutic antifibrotic agent for the treatment of hepatic fibrosis.

Association of functional polymorphisms of the transforming growth factor B1 gene with survival and graft-versus-host disease after unrelated donor hematopoietic stem cell transplantation

BACKGROUND

Many genetic factors play major roles in the outcome of hematopoietic stem cell transplants from unrelated donors. Transforming growth factor beta1 is a member of a highly pleiotrophic family of growth factors involved in the regulation of numerous immunomodulatory processes.

DESIGN AND METHODS

We investigated the impact of single nucleotide polymorphisms at codons 10 and 25 of TGFB1, the gene encoding for transforming growth factor beta1, on outcomes in 427 mye-loablative-conditioned transplanted patients. In addition, transforming growth factor beta1 plasma levels were measured in 263 patients and 327 donors.

RESULTS

Patients homozygous for the single nucleotide polymorphism at codon 10 had increased non-relapse mortality (at 3 years: 46.8% versus 29.4%, P=0.014) and reduced overall survival (at 5 years 29.3% versus 42.2%, P=0.013); the differences remained statistically significant in multivariate analysis. Donor genotype alone had no impact, although multiple single nucleotide polymorphisms within the pair were significantly associated with higher non-relapse mortality (at 3 years: 44% versus 29%, P=0.021) and decreased overall survival (at 5 years: 33.8% versus 41.9%, P=0.033). In the 10/10 HLA matched transplants (n=280), recipients of non-wild type grafts tended to have a higher incidence of acute graft-versus-host disease grades II-IV (P=0.052). In multivariate analysis, when analyzed with patients' genotype, the incidences of both overall and grades II-IV acute graft-versus-host disease were increased (P=0.025 and P=0.009, respectively) in non-wild-type pairs.

CONCLUSIONS

We conclude that increasing numbers of single nucleotide polymorphisms in codon 10 of TGFB1 in patients and donors are associated with a worse outcome following hematopoietic stem cell transplantation from unrelated donors.

Hepatic veno-occlusive disease after hematopoietic stem cell transplantation: update on defibrotide and other current investigational therapies

Hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), remains one of the most serious and common complications after myeloablative hematopoietic stem cell transplantation (HSCT). Clinical diagnosis of hepatic VOD is based on the clinical triad of (1) painful hepatomegaly, (2) hyperbilirubinemia and (3) unexplained fluid retention. While milder cases usually resolve spontaneously, severe VOD is associated with a grim prognosis. Defibrotide (DF), a polydisperse mixture of single-stranded oligonucleotide with antithrombotic and fibrinolytic effects on microvascular endothelium, has emerged as an effective and safe therapy for patients with severe VOD. Multiple studies, including a recent large international multicenter phase II clinical trial, have demonstrated 30-60% complete remission rates with DF, even among patients with severe VOD and multiorgan failure. This article will review our current understanding of hepatic VOD, and update the clinical trial experience with DF and other potential therapies for this feared transplant complication.

Changes in circulating human endothelial progenitor cells after brain injury

Endothelial progenitor cells (EPCs) are mobilized from the bone marrow to blood circulation in response to tramatic or inflammatory stimulations. Once released, they actively seek and home to the sites of vascular injury to promote vascular repair. We monitored changes of EPC counts in peripheral blood of 29 patients with traumatic brain injury for up to 21 days. We showed that the levels of circulating EPCs within the first 48 h of injury were lower than control subjects, but increased over time-reaching plateau around 7 days post-injury at a level that was significantly higher than controls. The initial EPC reduction, which was severe in patients with severe injury Glasgow Coma Scale [GCS] < 12), differs from the acute increase in EPC counts found in patients with cardiovascular injury. The subsequent increase in circulating EPCs is primarily through bone marrow mobilization because the cells were stained predominantly for CD133, which labels immature EPCs, but not CD34 (which stains cell of endothelial lineage). The increase appeared earlier in male patients and was greater in those younger than 50 years of age. Changes in circulating EPCs during follow-up periods correlated with platelet, but not leukocyte counts. These results suggest that EPC mobilization following traumatic brain injury may take a different course compared to that associated with body or vascular injuries.

Defibrotide, a polydisperse mixture of single-stranded phosphodiester oligonucleotides with lifesaving activity in severe hepatic veno-occlusive disease: clinical outcomes and potential mechanisms of action

Veno-occlusive disease of the liver (VOD) remains a troubling and potentially fatal complication of high-dose chemotherapy and hematopoietic stem cell transplantation conditioning regimens. No effective therapy has been available for these patients to date, and the best supportive care measures remain woefully inadequate. Defibrotide (DF) (Gentium, S.p.A., Como, Italy), a polydisperse mixture of all the single-stranded phosphodiester oligodeoxyribonucleotides that can be obtained from the controlled depolymerization of porcine intestinal mucosal genomic DNA, seems to offer a safe and effective treatment for some patients suffering from severe VOD, a condition for which no accepted standard therapy currently exists. Early clinical studies evaluating the efficacy of DF for the treatment of severe VOD in patients undergoing hematopoietic stem cell transplantation have been very encouraging. Approximately 45% of the patients treated in multiple initial phase II clinical trials achieved a complete response at day +100, demonstrating normalization of serum bilirubin and resolution of the clinical syndrome. However, although multi-institutional, these represented single arm studies. A large, FDA-approved, pivotal, prospective, multi-institutional, global phase III trial of DF vs. historical controls (best available therapy) commenced in the first quarter of 2006 and should provide further validation of DF's efficacy. The drug seems to have few significant side effects, and almost all test subjects who have received this treatment have tolerated it well. Although the mechanism of action remains unclear, the drug exerts minimal systemic anticoagulant effects yet appears to induce numerous antithrombotic and profibrinolytic effects both in vitro and in vivo. It may function as an adenosine receptor agonist and causes increased concentrations of endogenous prostaglandins, which modulate thrombomodulin, platelets, and fibrinolysis. It also appears to block lipopolysaccharide (LPS)-induced tissue factor (TF) expression. However, despite the fact the DF is composed of oligonucleotides, its mechanism of action, which at the present time is unclear, is not related to Watson-Crick base pair-dependent downregulation of gene expression but is rather likely a result of its polyanionic nature.