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.

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.

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.

The mouse model of hepatic veno-occlusive disease

With the application of hematopoietic stem cell transplantation, Subacute or acute increase in the incidence of hepatic veno-occlusive disease (HVOD) becomes more common and it can lead to fatal complications. This article characterizes a mouse model of HVOD induced by monocrotaline. After gavage with monocrotaline was performed on BALB/c mice, On the 3rd, 4th, 6th, 8th and 10th days, mice were anesthetized, blood was collected and the liver was removed. Liver slices were processed by HE stain, Masson's trichrome stain or immunohistochemical stain. From days 3 through 4, histopathology and cytokine changes were determined as severe, early HVOD. From days 6 through 8, the changes were considered to represent late HVOD. On the 10th day, the above changes showed that late HVOD gradually improved.

Characterization of liver injury induced by a pyrrolizidine alkaloid in rats

BACKGROUND

Pyrrolizidine alkaloids (PAs) are common phytotoxins. PA intoxication is reported to cause severe acute liver damage, typically known as hepatic sinusoidal obstruction syndrome (HSOS), but it remains obscure whether the acute liver damage may progress into chronic liver disease characterized by hepatic fibrosis.

PURPOSE

This study aims to characterize the biochemical markers of liver injury and histological features of regressive and progressive liver fibrosis, and to examine changes in hepatic gene expression that may underpin mechanisms of fibrogenesis in rats induced by retrorsine (RTS), a representative toxic PA.

STUDY DESIGN/METHODS

Rats were gavaged with RTS via two dosing regimens, i.e. a single dose of 40 mg/kg (Group 1) and two doses of 40 mg/kg and 20 mg/kg on day 0 and day 7 (Group 2), respectively. Rats receiving one (Group 3) or two (Group 4) doses of vehicle served as negative controls. The animals were followed for up to 16 weeks by serum biochemical analyses and histological examination, and gene expression assays of liver tissues.

RESULTS

Acute liver injury on day 2 manifested as HSOS, characterized by sinusoidal dilation, endothelial cell damage, and elevated serum alanine aminotransferase activity and bilirubin levels. In Group 1, mild liver fibrosis developed at sinusoids and perisinusoidal space surrounding the central veins at week 1 and 2, and thereafter, all liver injury resolved gradually. In Group 2, liver fibrosis progressed within the 16-week observation period. No apparent liver injury was observed in Groups 3 and 4. Compared with negative control groups, RTS induced myofibroblastic activation, TGF-β1 signaling, and changes in expression of matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1). These dynamic changes differed in Groups 1 and 2, corresponding with the regression and progression of liver fibrosis, respectively, in these groups.

CONCLUSION

This study has provided in-vivo proof of concept that "one hit" and "two hits" of RTS lead to acute resolving liver injury and chronic progressive liver fibrosis, respectively. These animal models may serve as powerful tools for studying RTS toxicology and related preventive and therapeutic strategies and as positive controls for studying other PA- and non-PA-induced liver injury.

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.

Liver stiffness and perfusion changes for hepatic sinusoidal obstruction syndrome in rabbit model

BACKGROUND

Hepatic sinusoidal obstruction syndrome (SOS) is caused by damage to hepatic sinusoidal endothelial cells that results in fibrous obliteration of intrahepatic venules and necrosis of hepatocytes. Currently the diagnosis is primarily based on nonspecific clinical features and invasive liver biopsy. Therefore, noninvasive imaging methods are required for the early diagnosis and severity assessment of hepatic SOS.

AIM

To determine the effectiveness of supersonic shear wave imaging (SSI) and dual energy computed tomography (DECT) for diagnosing hepatic SOS using a rabbit model.

METHODS

Among nine New Zealand white rabbits (3-4 kg, male), three in control group ingested normal saline for 20 d and six in the SOS group ingested 6-thioguanine (5 mg/kg/d) for 20 d. Liver stiffness was measured using SSI on days 0, 3, 10, and 20. On the same days, liver perfusion was evaluated from virtual monochromatic images of 55 keV and iodine map using DECT. Morphologic changes in the liver were assessed using CT. Final pathology scores were compared between the two groups. Liver stiffness and perfusion parameters were compared according to the groups, days, and pathology scores.

RESULTS

Final pathology scores were significantly higher in the SOS than the control group (median 22 vs 2, P = 0.024). No gross morphologic changes were seen in livers. Liver stiffness, Hounsfield Unit values, and iodine concentrations were higher in the SOS compared to the control group on days 10 and 20 (all, P ≤ 0.007). Compared to day 0, liver stiffness and perfusion parameters were higher on day 20 in the SOS group (all, P ≤ 0.001). Correlation coefficients for liver stiffness (r = 0.635), Hounsfield Unit values (r = 0.587), and iodine concentration (r = 0.611) with final pathology scores were positive without significance (all, P > 0.05).

CONCLUSION

Liver stiffness and perfusion parameters were significantly increased in the livers of a rabbit SOS model. SSI and DECT might aid in early diagnosis of hepatic SOS.

Role of Virtual Touch Tissue Imaging Quantification in the Assessment of Hepatic Sinusoidal Obstruction Syndrome in a Rat Model

OBJECTIVES

To investigate the value of liver stiffness in rats with various degrees of hepatic sinusoidal obstruction syndrome (HSOS) induced by monocrotaline by comparing liver histopathologic findings.

METHODS

Seventy rats were randomly divided into a control group (n = 10), a low-dose monocrotaline group (n = 30), and a high-dose monocrotaline group (n = 30). After successful modeling, the liver shear wave velocity (SWV) by Virtual Touch tissue imaging quantification (Siemens Medical Solutions, Mountain View, CA) and the alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin levels of the groups were obtained on days 3 and 5, and the intergroup differences were compared. Liver histopathologic characteristics were analyzed to evaluate the degrees of HSOS, and the scores were recorded.

RESULTS

On days 3 and 5, the total bilirubin, AST, and ALT, levels and liver SWV in the low- and high-dose groups were elevated; the portal vein velocity (PVV) of these groups was decreased compared with the control group; and the high-dose rats showed higher serum AST and ALT levels than the low-dose rats. The high-dose rats had a lower PVV than the low-dose rats at day 3. The liver SWV values had significant correlations with the histologic score and PVV. In a multivariate analysis, the liver SWV (β = 0.813; P < .001) was independently associated with the histopathologic score.

CONCLUSIONS

Liver stiffness as measured by Virtual Touch tissue imaging quantification increases with the severity of HSOS and can be recommended as a marker for diagnosis and assessment of HSOS.

No free rides: management of toxicities of novel immunotherapies in ALL, including financial

Therapeutic options for acute lymphoblastic leukemia, especially in the relapsed/refractory setting, have expanded significantly in recent times. However, this comes at the cost of toxicities: medical as well as financial. We highlight some of the unique toxicities associated with the novel agents to apprise our readers about what to expect, how to recognize them, and how to manage these toxicities. One of the toxicities seen with inotuzumab, a CD22 antibody drug conjugate, is sinusoidal obstruction syndrome, which can be fatal in >80% of patients if associated with multiorgan failure. Blinatumomab, a monoclonal antibody targeting CD19, is associated with cytokine release syndrome (CRS) and neurotoxicity, both of which require prompt recognition and management primarily with corticosteroids. CRS and neurotoxicity are more common and more severe with chimeric antigen receptor T-cell therapy (CAR-T). The fact that CAR-T cannot be discontinued on demand adds a layer of complexity to the management of related toxicities of this therapy. Tocilizumab, an interleukin-6 receptor blocker, is used to treat severe CRS from CAR-T, whereas corticosteroids remain the mainstay for neurotoxicity management. Although effective, these drugs carry a high price tag, and we review the available data on cost-effectiveness of these agents, keeping in mind that median follow-up on most of these studies is limited and that long-term data on durability of response remain to be seen.

Management of hepatic vein occlusive disease after liver transplantation: A case report with literature review

RATIONALE

Hepatic vein occlusive disease (HVOD) is a rare complication after liver transplantation, which is characterized by nonthrombotic, fibrous obliteration of the small centrilobular hepatic veins by connective tissue and centrilobular necrosis in zone 3 of the acini. HVOD after solid organ transplantation has been reported; recently, most of these reports with limited cases have documented that acute cell rejection and immunosuppressive agents are the major causative factors. HVOD is relatively a rare complication of liver transplantation with the incidence of approximately 2%.

PATIENT CONCERNS

A 59-year-old male patient with alcoholic liver cirrhosis underwent liver transplantation in our center. He suffered ascites, renal impairment 3 months after the surgery while liver enzymes were in normal range.

DIAGNOSES

Imagining and pathology showed no evidence of rejection or vessels complications. HVOD was diagnosed with pathology biopsy.

INTERVENTIONS

Tacrolimus was withdrawn and the progression of HVOD was reversed.

OUTCOMES

Now, this patient has been followed up for 6 months after discharge with normal liver graft function.

LESSONS

The use of tacrolimus in patients after liver transplantation may cause HVOD. Patients with jaundice, body weight gain, and refractory ascites should be strongly suspected of tacrolimus related HVOD.

Diagnosis and severity criteria for sinusoidal obstruction syndrome/veno-occlusive disease in pediatric patients: a new classification from the European society for blood and marrow transplantation

The advances in hematopoietic cell transplantation (HCT) over the last decade have led to a transplant-related mortality below 15%. Hepatic sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is a life-threatening complication of HCT that belongs to a group of diseases increasingly identified as transplant-related, systemic endothelial diseases. In most cases, SOS/VOD resolves within weeks; however, severe SOS/VOD results in multi-organ dysfunction/failure with a mortality rate >80%. A timely diagnosis of SOS/VOD is of critical importance, given the availability of therapeutic options with favorable tolerability. Current diagnostic criteria are used for adults and children. However, over the last decade it has become clear that SOS/VOD is significantly different between the age groups in terms of incidence, genetic predisposition, clinical presentation, prevention, treatment and outcome. Improved understanding of SOS/VOD and the availability of effective treatment questions the use of the Baltimore and Seattle criteria for diagnosing SOS/VOD in children. The aim of this position paper is to propose new diagnostic and severity criteria for SOS/VOD in children on behalf of the European Society for Blood and Marrow Transplantation.

Hepatic Sinusoidal Obstruction Syndrome Induced by Non-transplant Chemotherapy for Non-Hodgkin Lymphoma

Hepatic sinusoidal obstruction syndrome (SOS), a serious complication that mainly occurs after hematopoietic-stem cell transplantation (HSCT), is caused by damage to the sinusoidal endothelial cells after the obstruction of the sinusoid. Recently, hepatic SOS was reported to occur after non-HSCT chemotherapies. This report describes a patient who experienced hepatic SOS after non-HSCT chemotherapy for non-Hodgkin lymphoma. A liver biopsy showed the slight dilatation of the hepatic sinusoid, which may be indicative of hepatic SOS. Hepatic SOS should be included in the differential diagnosis of patients with severe liver injury following the administration of chemotherapy regimens that are toxic to the vascular endothelial cells.

Changes in Noninvasive Liver Fibrosis Indices and Spleen Size During Chemotherapy: Potential Markers for Oxaliplatin-Induced Sinusoidal Obstruction Syndrome

Oxaliplatin-based regimens are standard treatments for the patients with colorectal cancer (CRC) and advanced gastric cancer (AGC). However, owing to hepatic sinusoidal obstruction syndrome (SOS), the use of oxaliplatin sometimes results in splenomegaly. The aim of the present study was to evaluate the correlation between chemotherapy-associated changes of noninvasive liver fibrosis indices and volumetric changes of the spleen.From February 2004 to April 2014, patients with CRC or AGC receiving oxaliplatin-based chemotherapy were studied. The possibility of SOS development was evaluated before and after the oxaliplatin exposure with splenic volume index (SVI). Four different noninvasive liver fibrosis indices were used for risk analysis, namely age-platelet index (API), AST-to-platelet ratio index (APRI), platelet-to-spleen ratio (PSR), and fibrosis-4 score (FIB-4).A total of 275 patients were eligible for evaluation: 200 patients had CRC and 75 patients had AGC. Using the cutoff of SVI increase ≥ 0.3, 113 patients (41.1%) were positive for splenomegaly. The changes of indices significantly correlated with SVI increase. Adjusted odds ratios for those indices were as follows: API = 1.16 (95% confidential interval [CI], 1.01-1.32; P = .03); APRI = 2.45 (95% CI, 1.30-4.63; P = .01); PSR = 0.69 (95% CI, 0.59-0.80; P < .01); and FIB-4 = 1.37 (95% CI, 1.16-1.63; P < .01). Optimal cutoff values with statistical significance were calculated and suggested.The changes of noninvasive liver fibrosis indices showed a good correlation with the increase in the spleen volume during oxaliplatin-based chemotherapy. Validation of these indices for monitoring of oxaliplatin-induced hepatic SOS is warranted.

von Willebrand Factor-Rich Platelet Thrombi in the Liver Cause Sinusoidal Obstruction Syndrome following Oxaliplatin-Based Chemotherapy

Oxaliplatin-based chemotherapy is widely used to treat advanced colorectal cancer (CRC). Sinusoidal obstruction syndrome (SOS) due to oxaliplatin is a serious type of chemotherapy-associated liver injury (CALI) in CRC patients. SOS is thought to be caused by the sinusoidal endothelial cell damage, which results in the release of unusually-large von Willebrand factor multimers (UL-VWFMs) from endothelial cells. To investigate the pathophysiology of CALI after oxaliplatin-based chemotherapy, we analyzed plasma concentration of von Willebrand factor (VWF) and the distribution of VWFMs in CRC patients. Twenty-three patients with advanced CRC who received oxaliplatin-based chemotherapy with (n = 6) and without (n = 17) bevacizumab were analyzed. CALI (n = 6) and splenomegaly (n = 9) were found only in patients who did not treated with bevacizumab. Plasma VWF antigen (VWF:Ag) and serum aspartate aminotransferase (AST) levels increased after chemotherapy only in patients without bevacizumab. VWFM analysis in patients who did not receive bevacizumab showed the presence of UL-VWFMs and absence of high molecular weight VWFMs during chemotherapy, especially in those with CALI. In addition, plasma VWF:Ag and AST levels increased after chemotherapy in patients with splenomegaly (n = 9), but not in patients without splenomegaly (n = 14). Histological findings in the liver tissue of patients who did not receive bevacizumab included sinusoidal dilatation and microthrombi in the sinusoids. Many microthrombi were positive for both anti-IIb/IIIa and anti-VWF antibodies. Plasma UL-VWFM levels might be increased by damage to endothelial cells as a result of oxaliplatin-based chemotherapy. Bevacizumab could prevent CALI and splenomegaly through inhibition of VWF-rich platelet thrombus formation.

Is the sinusoidal obstructive syndrome post-liver transplantation a pathologic entity with a multifactorial etiology?

The sinusoidal obstructive syndrome is a complication typically associated with hematopoietic stem cell transplantation. This syndrome, more commonly known as veno-occlusive disease, has also been described after liver transplantation. It can have a life-threatening course. Herein, we describe the hepatic graft loss secondary to the development of a sinusoidal obstructive syndrome after a severe acute cellular rejection and toxic levels of once daily modified released tacrolimus (TAC). We discuss the role of the endotheliitis of acute rejection and toxic metabolites of some immunosuppressants such as azathioprine and TAC. Based on the current scientific evidence, we contemplate the possibility that the etiology of sinusoidal obstruction syndrome post-liver transplantation is multifactorial.

Cyclophosphamide followed by intravenous targeted busulfan for allogeneic hematopoietic cell transplantation: pharmacokinetics and clinical outcomes

Targeted busulfan ((T)BU) and cyclophosphamide (CY) for allogeneic hematopoietic cell transplantation carries a high risk of sinusoidal obstruction syndrome (SOS) in patients undergoing transplantation for myelofibrosis. We tested the hypothesis that reversing the sequence of administration (from (T)BU/CY to CY/(T)BU) would reduce SOS and day +100 nonrelapse mortality. We enrolled 51 patients with myelofibrosis (n = 20), acute myelogenous leukemia (n = 20), or myelodysplastic syndrome (n = 11) in a prospective trial of CY/(T)BU conditioning for allogeneic hematopoietic cell transplantation. CY 60 mg/kg/day i.v. for 2 days was followed by daily i.v. BU for 4 days, targeted to a concentration at steady state (Css) of 800-900 ng/mL. Compared with (T)BU/CY-conditioned patients, CY/(T)BU-conditioned patients had greater exposure to CY (P < .0001) and less exposure to 4-hydroxycyclophosphamide (P < .0001). Clinical outcomes were compared between cases and controls (n = 271) conditioned with (T)BU/CY for the same indications. In patients with myelofibrosis, CY/(T)BU conditioning was associated with a significantly reduced incidence of SOS (0% versus 30% after (T)BU/CY; P = .006), whereas the incidence of SOS was low in both cohorts with acute myelogenous leukemia/myelodysplastic syndrome. Day +100 mortality was significantly lower in the CY/(T)BU cohort (2% versus 13%; P = .01). CY/(T)BU conditioning had a marked affect on the pharmacokinetics of CY and was associated with significantly lower incidence of SOS and day +100 mortality, suggesting that CY/(T)BU is superior to (T)BU/CY as conditioning for patients with myelofibrosis.

[Effects of liver sinusoid endothelial cell injury in mouse hepatic veno-occlusive disease]

This study was purposed to investigate the role of monocrotaline-inducing mouse liver sinusoid endothelial cell (SEC) injury in hepatic veno-occlusive disease. BALB/c mice were randomly divided into 2 groups: control group and monocrotaline group, mice were orally administrated with normal saline or monocrotaline with concentration of 200 mg/kg at days 0, 1, 2, respectively. At days 3, 4, 6, 8 and 10 after oral administration with normal saline or monocrotaline, the liver function (ALT, TBIL, AKP) and liver index were examined, and the percentage of activated platelets were detected by flow cytometry. The SEC, vascular endothelial cells and hepatic fibrosis were observed by staining with hematoxylin-eosin and Masson. Transmission electron microscopy was used to observe sinusoidal endothelial cell damage and platelet adhesion. The results showed that compared with control group, mice in monocrotaline group were characterized by severe damage of SEC, numbers of platelet aggregation and adhesion, central number and sinusoidal fibrosis. The percentage of activated platelets and liver index increased (P < 0.05). The characterization of portal hypertension was presented later, such as dysfunction of liver and ascites. It is concluded that SEC injury induced by monocrotaline may be the first step of hepatic veno-occlusive disease, and this kind of SEC injury is self-limiting, but fibrosis is always observed.

An outbreak of veno-occlusive liver disease in northern Ethiopia, clinical findings

BACKGROUND

Following the emergence of an unidentified fatal disease in Tahtay Koraro, rural farmers' village in Tigray, northern Ethiopia since 2001, a team of experts from Addis Ababa University Medical Faculty was assigned in November 2005, to investigate the problem in the field. The team consisted of an Infectious disease specialist, a Gastroenterologist, an Epidemiologist, a Pathologist, and a Microbiologist. The team was also joined by a group of Tigray Regional Health Bureauprofessionals.

OBJECTIVES

To investigate the nature of unidentified liver disease, identify possible cause(s) and recommend specific interventions/treatment in order to save lives and stop further spread of the disease.

METHODS

Data were collected from Clinical history, clinical evaluation of the affected cases in the area, relevant laboratory investigations, and histopathologic studies.

RESULTS

The team evaluated sixty one of patients in the field (37 males and 24 females) with mean age of 27 years. The disease affected both gender and all age groups. Duration of the illness ranged from 1 month to 3 years with a median of 6 months. The illness was reported to have started with abdominal cramp in 75%, febrile syndrome in 77%, and abdominal distention in 63% of the cases. This was usually followed by jaundice, bleeding tendencies, and edematous states mainly in the form of rapidly filling ascites. Majority of the patients had similarly sick family members and/or lost family member(s) due to the same illness. Moreover, laboratory, sonography, histopathological, and toxicological studies revealed VOLD due to Pyrrolizidine alkaloid (PA) toxicity as described in the other sections of the supplement.

CONCLUSION

From a detailed clinical and epidemiological investigation as well as histopathological and toxicological analyses, the disease was found to be fatal toxic hepatitis (veno-occlusive liver disease (VOLD). To our knowledge, this is the first report of VOLD from Ethiopia.

Veno-occlusive liver disease: a case report

A case of veno-occlusive liver disease (VOLD) in a 12-years old Ethiopian boy is described The salient clinical features and gross and microscopic examination of biopsy material are reviewed. Veno-occlusive disease which occurs in the West Indies, East and West Africa, and India is an acute, subacute or chronic condition that affects the central and sublobular hepatic veins. In the West Indies (1) it is related to the consumption of bush tea made from plants that contain toxic pyrrolizidine alkaloids, such as Crotalaria and Senecio (2). Hepatotoxic compounds in Crotalaria, Senecio, Heliotropium and other composite plants can also enter the diet through the contamination of cereals with weed seeds. For example 28 of 67 patients died with veno-occlusive disease in central India after consuming a local cereal, gondli contaminated with the seeds of Crotalaria (3). Heliotropium Popovii has been implicated in outbreaks in villages in northwestern Afghanistan, with high mortality (4). The primary pathological change of hepatic veno-occlusive disease is sub-endothelial edema followed by intimal growth of connective tissue, with narrowing and occlusion of the central and sub-lobular hepatic veins. Atrophy or necrosis of liver cells, with consequent fibrosis leads to gross changes similar to those seen in cardiac cirrhosis, portal hypertension results. The present report, the first of it kind in Ethiopia describes a case of veno-occlusive liver disease in a 12-year old Ethiopian boy.

Successful treatment with danhong injection for hepatic veno-occlusive disease

Hepatic veno-occlusive disease (HVOD) is a clinical syndrome characterized as hepatomegaly, ascites, jaundice and elevation of hepatic enzymes as an outcome from fibrous obliteration of small centrilobular hepatic venules. It is recognized as a rare but life-threatening complication of organ transplantation, tumor eradication chemotherapy and is associated with haematopoietic stem cell transplantation (SCT). Recent researches report that ingestion of plants which contain pyrrolizidine alkaloids (PAs) is associated with the onset of HVOD with unclear pathogenesis. Nowadays, there is no effective therapeutic strategy for HVOD besides supportive care using diuretics or albumin. In our case, a 42-year-old woman administered a concoction of Chinese traditional medicine supposed to contain PAs, was found to develop HVOD confirmed by liver biopsy. A therapeutic strategy was developed using Danhong injection, accompanied with supportive care, and obtained a favorable response manifesting as regression of symptoms and decline of hepatic enzymes. Danhong injection, a Chinese medical product exerting a milder anticoagulation and antithrombotic effect, is beneficial to HVOD probably by promoting microcirculation, ameliorating liver function and inhibiting hepatic fibrosis.

Defibrotide for the treatment of severe hepatic veno-occlusive disease and multiorgan failure after stem cell transplantation: a multicenter, randomized, dose-finding trial

Therapeutic options for severe hepatic veno-occlusive disease (VOD) are limited and outcomes are dismal, but early phase I/II studies have suggested promising activity and acceptable toxicity using the novel polydisperse oligonucleotide defibrotide. This randomized phase II dose-finding trial determined the efficacy of defibrotide in patients with severe VOD following hematopoietic stem cell transplantation (HSCT) and identified an appropriate dose for future trials. Adult and pediatric patients received either lower-dose (arm A: 25 mg/kg/day; n = 75) or higher-dose (arm B: 40 mg/kg/day; n = 74) i.v. defibrotide administered in divided doses every 6 hours for > or =14 days or until complete response, VOD progression, or any unacceptable toxicity occurred. Overall complete response and day +100 post-HSCT survival rates were 46% and 42%, respectively, with no significant difference between treatment arms. The incidence of treatment-related adverse events was low (8% overall; 7% in arm A, 10% in arm B); there was no significant difference in the overall rate of adverse events between treatment arms. Early stabilization or decreased bilirubin was associated with better response and day +100 survival, and decreased plasminogen activator inhibitor type 1 (PAI-1) during treatment was associated with better outcome; changes were similar in both treatment arms. Defibrotide 25 or 40 mg/kg/day also appears effective in treating severe VOD following HSCT. In the absence of any differences in activity, toxicity or changes in PAI-1 level, defibrotide 25 mg/kg/day was selected for ongoing phase III trials in VOD.

[Veno-occlusive disease of the liver]

Veno-occlusive disease (VOD) is seen most often in the group of bone marrow transplant recipients. The essence of this disease is the obstruction of the hepatic sinusoidal and centrolobular venous outflow, because of the injury to the endothelium of the liver vessels. It results in congestion of the liver and hepatomegaly. The typical clinical symptoms of VOD are: jaundice, portal hypertension with peripheral oedemas and the weight gain. Depending on the extent of the injury of the hepatic vessels, VOD is divided into three grades: mild, moderate and severe. The clinical markers that inform about the severity of the disease are: the rate of the serum bilirubin growth and the rate of the weight gain growth within the first 2 weeks since the beginning of the disease. Severe VOD is the third of the most often cause of death among people who underwent bone marrow transplantation. The mortality rate is diverse and depends on severity of the disease. The effectiveness of the VOD therapy is limited, so it is worth putting greater pressure on the prophylaxis of VOD or on finding more effective modes of treatment.

Microscopic and macroscopic tumor and parenchymal effects of liver stereotactic body radiotherapy

PURPOSE

To describe the histologic and volumetric changes in normal liver tissue after stereotactic body radiotherapy (SBRT) for liver metastases.

METHODS AND MATERIALS

Pre- and post-SBRT imaging studies were analyzed to evaluate the effect of SBRT on normal liver volume (NLV) in 15 patients treated in a prospective clinical trial. Two other patients underwent exploratory surgery after SBRT and histologic analyses of the irradiated liver were performed to characterize the pathologic effects of SBRT.

RESULTS

In the 15 patients studied quantitatively, the total NLV had decreased transiently at 2-3 months after SBRT and then began to regenerate at 3-8 months after SBRT. The median NLV reduction at the maximal observed effect was 315 cm(3) (range, 125-600) or 19% (range, 13-33%). Among the several dosimetric parameters evaluated, the strongest linear correlation was noted for the NLV percentage receiving 30 Gy as a predictor of maximal NLV reduction (r(2) = 0.72). The histologic changes observed 2 and 8 months after SBRT demonstrated distinct zones of tissue injury consistent with localized veno-occlusive disease.

CONCLUSION

The well-demarcated focal parenchymal changes after liver SBRT (demonstrated both radiographically and histologically) within the high-dose zone are consistent with a threshold dose-induced set of phenomena. In contrast, the more global effect of NLV reduction, which is roughly proportional to whole organ dose parameters, resembles more closely an effect determined from radiobiologically parallel architecture. These observations suggest that modeling of normal tissue effects after liver SBRT might require different governing equations for different classes of effects.

[Clinical analysis of hepatic veno-occlusive disease induced by Sedum aizoon]

OBJECTIVE

To discuss the clinical characteristics and precautionary measures of hepatic veno-occlusive disease (VOD) caused by Sedum aizoon.

METHOD

The VOD induced by Sedum aizoon were reports in 41 patients comimg from national medical journals from 1998 to 2007 and their use and dose were analyzed.

RESULT

The results shows that ADR of Sedum aizoon was serious. VOD has relationship with it, s dose use time the age of the patients and individual difference.

CONCLUSION

To avoid of VOD induced by Sedum aizoon, it should be done through strengthening study on pharmacology and toxicology of Sedum aizoon. Enhancing patients of safety awareness, standardizing usage and dosage to guide the clinically rational use of drugs.

Veno-occlusive disease of the liver after lung transplantation

Veno-occlusive disease (VOD) of the liver is mainly described after chemo-irradiation conditioning regimens during haematopoietic stem cell transplantation (SCT) and has been sporadically reported after kidney and liver transplantation. In the latter cases, it is commonly attributed to azathioprine and/or tacrolimus. One case of tacrolimus-induced hepatic VOD developing after lung transplantation (LT) has been recently reported. Here we describe another case of VOD occurring after LT, but in which the causative role was played by azathioprine.

Prophylactic fresh frozen plasma may prevent development of hepatic VOD after stem cell transplantation via ADAMTS13-mediated restoration of von Willebrand factor plasma levels

We initially conducted a multicenter, randomized trial (n=43), and subsequently a questionnaire study (n=209) of participating hospitals, to evaluate whether infused fresh frozen plasma (FFP) could prevent the occurrence of hepatic veno-occlusive disease (VOD) after stem cell transplantation (SCT). Forty-three patients were divided into two groups: 23 receiving FFP infusions and 20 not receiving it. VOD developed in three patients not receiving FFP. Plasma von Willebrand factor (VWF) antigen levels were lower at days 0, 7 and 28 after SCT in patients receiving FFP than in those not receiving it, whereas plasma ADAMTS13 activity (ADAMTS13:AC) did not differ between them. Plasma VWF multimer (VWFM) was demonstrated to be defective in the high approximately intermediate VWFM during the early post-SCT phase, but there was a significant increase in high VWFM just before VOD onset. This suggests that a relative enzyme-to-substrate (ADAMTS13/high-VWFM) imbalance is involved in the pathogenesis of VOD. To strengthen this hypothesis, the incidence of VOD was apparently lower in patients receiving FFP infusions than in those not receiving it (0/23 vs 3/20) in the randomized trial. Further, the results combined with the subsequent questionnaire study (0/36 vs 11/173) clearly showed the incidence to be statistically significant (0/59 vs 14/193, P=0.033).

Hepatic venous outflow obstruction: Three similar syndromes

Our goal is to provide a detailed review of veno-occlusive disease (VOD), Budd-Chiari syndrome (BCS), and congestive hepatopathy (CH), all of which results in hepatic venous outflow obstruction. This is the first article in which all three syndromes have been reviewed, enabling the reader to compare the characteristics of these disorders. The histological findings in VOD, BCS, and CH are almost identical: sinusoidal congestion and cell necrosis mostly in perivenular areas of hepatic acini which eventually leads to bridging fibrosis between adjacent central veins. Tender hepatomegaly with jaundice and ascites is common to all three conditions. However, the clinical presentation depends mostly on the extent and rapidity of the outflow obstruction. Although the etiology and treatment are completely different in VOD, BCS, and CH; the similarities in clinical manifestations and liver histology may suggest a common mechanism of hepatic injury and adaptation in response to increased sinusoidal pressure.

Chemotherapy-associated hepatotoxicity and surgery for colorectal liver metastases

BACKGROUND

Preoperative systemic chemotherapy is increasingly used in patients who undergo hepatic resection for colorectal liver metastases (CLM). Although chemotherapy-related hepatic injury has been reported, the incidence and the effect of such injury on patient outcome remain ill defined.

METHODS

A systematic review of relevant studies published before May 2006 was performed. Studies that reported on liver injury associated with preoperative chemotherapy for CLM were identified and data on chemotherapy-specific liver injury and patient outcome following hepatic resection were synthesized and tabulated.

RESULTS

Hepatic steatosis, a mild manifestation of non-alcoholic fatty liver disease (NAFLD), may occur after treatment with 5-fluorouracil and is associated with increased postoperative morbidity. Non-alcoholic steatohepatitis, a serious complication of NAFLD that includes inflammation and hepatocyte damage, can occur after treatment with irinotecan, especially in obese patients. Irinotecan-associated steatohepatitis can affect hepatic reserve and increase morbidity and mortality after hepatectomy. Hepatic sinusoidal obstruction syndrome can occur in patients treated with oxaliplatin, but does not appear to be associated with an increased risk of perioperative death.

CONCLUSION

Preoperative chemotherapy for CLM induces regimen-specific hepatic changes that can affect patient outcome. Both response rate and toxicity should be considered when selecting preoperative chemotherapy in patients with CLM.

Hepatic veno-occlusive disease after neoadjuvant treatment of colorectal liver metastases with oxaliplatin: a lesson of the month

A patient is presented who was treated with neoadjuvant oxaliplatin-based chemotherapy followed by hepatic resection complicated by fatal liver failure. Histopathological examination revealed hepatic veno-occlusive disease, which is an infrequent reported side effect of oxaliplatin.

A case report of hepatic veno-occlusive disease after ingesting dainties

Hepatic veno-occlusive disease (HVOD) is rarely encountered and easily misjudged as Budd-Chiari syndrome. It is often related to stem cell transplantation in recent years. We report a case of HVOD that is related to ingestion of some palatable local dishes. The diagnosis was confirmed by liver biopsy pathology with specific observation of inflammatory changes and fibrosis of venules intima, dilated sinusoids and central veins. Chronic diarrhea is unique for this case as a result of ingesting harmful stuffs. This case demonstrated that supervision and instruction of food recipe and traditional medicine are crucial, and prompt diagnosis, supportive care and specific treatment are essential to decreasing the morbidity and mortality of HVOD.

Mechanisms and pathophysiological implications of sinusoidal endothelial cell gap formation following treatment with galactosamine/endotoxin in mice

Neutrophil extravasation from sinusoids is a critical step for acute inflammatory tissue injury. However, the role of sinusoidal endothelial cells (SECs) in this process remains unclear. Matrix metalloproteinases (MMPs) have been shown to involve gap formation in SECs in several liver diseases. Therefore, the present study examined SEC modifications elicited by galactosamine (Gal)/endotoxin (ET). Treatment of male C3Heb/FeJ mice with Gal/ET or Gal/TNF caused the formation of numerous gaps in SECs at 4 h when no neutrophil extravasation occurred. Six hours after Gal/ET or Gal/TNF treatment, blood elements started to penetrate to the extrasinusoidal space through large gaps. Treatment with ET alone caused sinusoidal neutrophil accumulation but no gap formation, neutrophil extravasation, or hemorrhage. Gal/ET treatment increased hepatic MMP-2 and MMP-9 mRNA expression (6.7- and 11-fold, respectively). Pretreatment with 2-[(4-biphenylsulfonyl) amino]-3-phenyl-propionic acid, an MMP-2/MMP-9 inhibitor (5 mg/kg), minimized gap formation after Gal/ET and Gal/TNF treatment. The MMP inhibitor reduced injury only in the Gal/ET model mainly due to reduced TNF formation. The MMP inhibitor attenuated sinusoidal neutrophil accumulation at 6 h but failed to attenuate Gal/TNF-induced liver injury at 7 h due to excessive apoptosis. These results suggest that Gal/ET or Gal/TNF activates MMPs, which are responsible for SEC gap formation. Although the initial appearance of gap formation is independent of neutrophils, the gaps allow initial contact of neutrophils with damaged hepatocytes. In addition, MMP activation promotes neutrophil accumulation in sinusoids.

Severe hepatic sinusoidal obstruction associated with oxaliplatin-based chemotherapy in patients with metastatic colorectal cancer

BACKGROUND

In advanced metastatic colorectal adenocarcinoma, the addition of a neo-adjuvant systemic treatment to surgery might translate into a survival advantage, although this is yet to be confirmed by ongoing randomized trials. The objective of this study was to assess the effects of preoperative systemic chemotherapy on the morphology of non-tumoral liver.

PATIENTS AND METHODS

A large series of surgically resected liver metastases (n=153) was selected. Light microscopy, electron microscopy, and immunohistochemistry using antibodies against endothelial cells (CD31) and hepatic stellate cells (alpha-SM actin, CRBP-1) were performed to identify sinusoidal wall integrity.

RESULTS

We found that 44 (51%) of the 87 post-chemotherapic liver resection specimens had sinusoidal dilatation and hemorrhage, related to rupture of the sinusoidal barrier. In contrast, the 66 livers treated by surgery alone remained normal. In 21 out of the 44 post-chemotherapy patients (48%), perisinusoidal and veno-occlusive fibrosis also developed. Sinusoidal injury persisted several months after end of chemotherapy, and fibrosis may progress. Development of lesions was strongly correlated to the use of oxaliplatin; 34 out of 43 patients (78%) treated with this drug showed striking sinusoidal alterations.

CONCLUSIONS

Systemic neo-adjuvant chemotherapy in metastatic colorectal cancer frequently causes morphological lesions involving hepatic microvasculature. Sinusoidal obstruction, complicated by perisinusoidal fibrosis and veno-occlusive lesion of the non-tumoral liver revealed by this study, should be included in the list of the adverse side-effects of colorectal systemic chemotherapy, in particular related to the use of oxaliplatin.

Early graft failure due to a veno-occlusive disease after a pediatric living donor liver transplantation

A 10-month-old boy with biliary atresia after Kasai procedure underwent a living donor liver transplantation (LDLT). Five days after the LDLT, high fever and increased ascites followed by poor bile drainage was accompanied by elevation of serum liver enzymes. Liver biopsy showed occlusion of the central veins by fibro-edematous endothelium and submassive necrosis of the parenchyma. Veno-occlusive disease (VOD) was suspected, and re-LDLT was urgently performed because of deterioration of hepatic failure. There are few cases of VOD after liver transplantation and this is the first one in an infant after LDLT.

Chylous ascites in a cheetah (Acinonyx jubatus) with venoocclusive liver disease

An 11-yr-old female cheetah (Acinonyx jubatus) was diagnosed clinically with hepatic and renal disease and euthanatized after an extended illness. Postmortem examination revealed 8-10 L of milky white fluid in the abdominal cavity and markedly dilated lymphatic vessels within the intestinal mesentery. The abdominal fluid was a chylous effusion based on the cytologic predominance of lymphocytes and macrophages and comparison of cholesterol and triglyceride levels in the fluid and in serum. Gross and histopathologic lesions in the liver were consistent with a diagnosis of venoocclusive liver disease. Chylous ascites is uncommon with human chronic liver disease and is rarely identified in animals.

The pathogenesis of nonalcoholic steatohepatitis and other fatty liver diseases: a four-step model including the role of lipid release and hepatic venular obstruction in the progression to cirrhosis

Fatty liver disease involves the accumulation of triglycerides in hepatocytes, necrosis of hepatocytes, inflammation, and often fibrosis with progression to cirrhosis. The two-hit model summarizes the important early metabolic events leading to hepatocellular necrosis in nonalcoholic steatohepatitis (NASH). In this article, we provide evidence of lipid release from hepatocytes in posttransplant fat necrosis and in NASH and quantify vascular obliteration in a series of biopsies with NASH. Obliteration of small hepatic veins (<30 microm) in small numbers is compensated by collateral flow. Obliteration of larger hepatic veins (>30 microm) is associated with fibrotic collapse lesions that are not easily resorbed. Based on these observations, we propose a new four-step model that includes the later events that lead to cirrhosis after necrosis has occurred. This model is applicable to nonalcoholic fatty liver disease (NAFLD), alcoholic disease, postjejunoileal bypass disease, and posttransplant fat necrosis. The first step is steatosis facilitated by insulin, and the second is necrosis induced by intracellular lipid toxicity or lipid peroxidation, or both, modified by alcohol, drugs, and ischemia. The third step is release of bulk lipid from hepatocytes into the interstitium leading to direct and inflammatory injury to hepatic veins. The fourth step is venous obstruction with secondary collapse and ultimately fibrous septation and cirrhosis.

Dactinomycin-induced veno-occlusive disease in rats. The hepatoprotective action of amifostine. Evaluation in a light and electron microscope

The purpose of the study was to draw upan experimental model of hepatic veno-occlusive disease (VOD) induced by dactinomycin (ACT) and to investigate the possible hepatoprotective effects of Ethyol (amifostine). Pathological changes corresponding to a VOD picture of varying intensification were found in the liver samples obtained from all the rats receiving ACT. Amifostine appears to act protectively to liver changes caused by dactinomycin.

Role of macrophages and stellate cells in the pathogenesis of veno-occlusive disease: an electron microscopic case study

Veno-occlusive disease (VOD) is an entity described as a triad of pathologic findings including ascites, tender hepatomegaly, and elevated liver enzymes. The prognosis of patients suffering from VOD is highly variable, ranging from slow resolution to the need for liver transplant. The histopathology of VOD has been described by light and electron microscopy. However, the pathogenesis of VOD is still largely unclear. In the present case study, we report the significant findings in a case of pediatric VOD following chemotherapy. We studied the liver biopsy by light and electron microscopes. In addition to previous reported findings of occlusion of the central vein with endothelial cell damage, proliferation and activation of stellate cells, and collagen deposition in the central vein wall, there were prominent activated macrophages within the lumen and wall of central veins. The following mechanism of VOD was proposed: Tissue damage activates monocytes through monocyte chemoattractant protein-1. The secretory macrophages release TGF-beta, which promotes proliferation of stellate cells to cause collagenous thickening of the central vein. The activated stellate cells produce collagen. The normal drainage of the Space of Disse and sinusoids draining into the central vein are blocked by the fibrosis. This leads to extravasated RBCs trapped within the thickened central vein wall and impaction of RBCs in the sinusoids.

Monthly prospective analysis of hematopoietic chimerism after allogeneic hematopoietic cell transplantation

SUMMARY

Hematopoietic chimerism (HpC) was assayed monthly using a sensitive, polymerase chain reaction (PCR) -based method in consecutive patients. Between January 1998 and April 2002, 181 patients underwent non-T cell depleted allogeneic hematopoietic cell transplantation (HCT). A total of 163 patients were evaluable for HpC at 1 month (11 early deaths; no informative band for HpC analysis/no genomic DNA in seven). In all, 53 of 163 patients (33%, median recipient DNA of 15% (range 5-95)), 39 of 151 patients (26%), and 27 of 142 patients (19%) showed mixed chimerism (MC) at 1, 2, and 3 months after HCT, respectively. Conditioning regimen (busulfan-fludarabine-ATG vs BuCy, relative risk 3.99 (95% CI 1.16-10.92)), neutrophil engraftment (>/=day 17 vs </=day 16, relative risk 2.49 (95% CI 1.14-5.41)), and acute graft-versus-host disease within 30 days (none vs yes, relative risk 4.78 (95% CI 1.50-15.17)) were independent variables that showed significant correlation with having >/=5% recipient DNA at 1 month. Five patients experienced secondary graft failure. All five patients showed MC at 1 month with median recipient DNA of 40%. None of the 109 patients with complete chimerism experienced graft failure (P=0.002). Our study showed that MC shown on monthly analysis of HpC after allogeneic HCT is a significant predictor of secondary graft failure. Bone Marrow Transplantation (2003) 32, 423-431. doi:10.1038/sj.bmt.1704147

Proinflammatory cytokines and their role in the development of major transplant-related complications in the early phase after allogeneic bone marrow transplantation

Serum levels of interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor (TNF)-alpha were frequently measured during the first 30 days after allogeneic bone marrow transplantation (BMT) in 84 consecutive adult patients. Major transplant-related complications (MTCs) occurred in 33% of cases and included veno-occlusive liver disease, idiopathic pneumonia syndrome, severe endothelial leakage syndrome and >grade II acute graft-versus-host disease. Compared with patients having minor complications, those with MTCs developed higher levels at times of maximal clinical signs (all cytokines, P<0.001), between days 0-5 post-BMT (IL-6 and IL-8, P<0.05) and days 6-10 (L-6, P<0.001; IL-8 and TNF, P<0.01) post-BMT. We could not discriminate patterns of cytokine release that were specific for any subtype of MTC. Higher levels of IL-8 during days 0-5 were associated (P=0.044) with early (<40 days) death. Multivariate analysis including patient and transplant characteristics as well as post-BMT levels of C-reactive protein showed that high average levels of one or more of the cytokines within the first 10 days post-BMT were independently associated with MTC (Odd's ratio: 2.3 [1.2-4.5], P=0.011). This study shows that systemic release of proinflammatory cytokines contributes to the development of MTC and provides a rationale for pre-emptive anti-inflammatory treatment in selected patients.

Hepatic veno-occlusive disease (sinusoidal obstruction syndrome) after hematopoietic stem cell transplantation

Hepatic veno-occlusive disease (VOD), increasingly referred to as sinusoidal obstruction syndrome, is a well-recognized complication of hematopoietic stem cell transplantation and contributes to considerable morbidity and mortality. In the Western Hemisphere, VOD, classified as a conditioning-related toxicity, is most commonly caused by stem cell transplantation. VOD has been described after all types of stem cell transplantation, irrespective of the stem cell source, type of conditioning therapy, or underlying disease. Recognition of this disease in the posttransplantation setting remains a challenge in the absence of specific diagnostic features because many other more common conditions can mimic it. Limited therapeutic or preventive strategies are currently available for the management of VOD. In this review, we provide a comprehensive account of the pathophysiology of this disease as we understand it today, risk factors for its development, and the current state of knowledge regarding preventive and therapeutic options.