Evaluation of Circulating Endothelial Cells as Direct Marker of Endothelial Damage in Allo-Transplant Recipients at High Risk of Hepatic Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome.

Sinusoidal obstruction syndrome (SOS), also known as veno-occlusive disease (VOD), is a rare but potentially fatal complication following allogenic hematopoietic cell transplantation (allo-HCT). Timely identification of SOS/VOD to allow for prompt treatment is critical, but identifying a VOD-predictive biomarker remains challenging. Given the pivotal role of endothelial dysfunction in SOS/VOD pathophysiology, the CECinVOD study prospectively evaluated levels of circulating endothelial cells (CECs) in patients undergoing allo-HCT with a myeloablative conditioning (MAC) regimen to investigate the potential of CEC level in predicting and diagnosing SOS/VOD. A total of 150 patients from 11 Italian bone marrow transplantation units were enrolled. All participants were age >18 years and received a MAC regimen, putting them at elevated risk of developing SOS/VOD. Overall, 6 cases of SOS/VOD (4%) were recorded. CECs were detected using the Food and Drug Administration-approved CellSearch system, an immunomagnetic selection-based platform incorporating ferrofluid nanoparticles and fluorescent-labeled antibodies, and were defined as CD146+, CD105+, DAPI+, or CD45-. Blood samples were collected at the following time points: before (T0) and at the end of conditioning treatment (T1), at neutrophil engraftment (T2), and at 7 to 10 days postengraftment (T3). For patients who developed VOD, additional samples were collected at any suspected or proven VOD onset (T4) and weekly during defibrotide treatment (T5 to T8). A baseline CEC count >17/mL was associated with an elevated risk of SOS/VOD (P = .04), along with bilirubin level >1.5 mg/mL and a haploidentical donor hematopoietic stem cell source. Postconditioning regimen (T1) CEC levels were elevated (P = .02), and levels were further increased at engraftment (P < .0001). Additionally, patients developing SOS/VOD after engraftment, especially those with late-onset SOS/VOD, showed a markedly higher relative increase (>150%) in CEC count. Multivariate analysis supported these findings, along with a high Endothelial Activation and Stress Index (EASIX) score at engraftment (T2). Finally, CEC kinetics corresponded with defibrotide treatment. After the start of therapy (T4), CEC levels showed an initial increase in the first week (T5), followed by a progressive decrease during VOD treatment (T6 and T7) and a return to pre-SOS/VOD onset levels at resolution of the complication. This prospective multicenter study reveals a low incidence of SOS/VOD in high-risk patients compared to historical data, in line with recent reports. The results from the CECinVOD study collectively confirm the endothelial injury in allo-HCT and its role in in the development of SOS/VOD, suggesting that CEC level can be a valuable biomarker for diagnosing SOS/VOD and identifying patients at greater risk of this complication, especially late-onset SOS/VOD. Furthermore, CEC kinetics may support treatment strategies by providing insight into the optimal timing for discontinuing defibrotide treatment.

Plateletcrit for predicting prognosis in patients with hepatic sinusoidal obstruction syndrome caused by pyrrolizidine alkaloid.

BACKGROUND: Platelet index was reported to be used as a potential prognostic marker in patients with liver fibrosis. We aimed to explore the association between plateletcrit (PCT) and severity of hepatic sinusoidal obstruction syndrome (HSOS). METHODS: Seventy consecutive patients who diagnosed as HSOS by CT and medical history during January 2017-November 2021 were included. All patients were divided into two groups which confirmed as favorable prognosis and poor prognosis on the basis of Child-Turcotte-Pugh score system. The clinical manifestation and laboratory parameters of two groups were retrospectively selected. PCT was evaluated within two groups, and the diagnostic accuracy was evaluated by the area under the receiver operating characteristic curve. RESULTS: The significant difference between the two groups not only in diarrhea, abdominal pain, abdominal distention, urine volume, and skin ecchymosis (p < 0.005), but also in WBC count, NE count, PLT count, TBIL, and D-Dimer (p < 0.005) were found. The PCT level was significantly higher in HSOS patients with poor prognosis (0.169 ± 0.060) than favorable prognosis patients (0.110 ± 0.047). The area under the receiver operating characteristic curve of RDW in predicting poor prognosis was 0.781, with 67.70% sensitivity and 79.5%specificity. CONCLUSIONS: The PCT level was correlated positively with the poor prognosis in HSOS patients. PCT can be a promising indicator for predicting prognosis in HSOS.

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

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

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.

Platelets prevent the development of monocrotaline-induced liver injury in mice.

Destruction of liver sinusoidal endothelial cells (LSECs) is an initial event in sinusoidal obstruction syndrome (SOS) that leads to accumulation of platelets in the liver. Herein, we explored the role of platelets during progression of experimental SOS induced by monocrotaline (MCT) in mice. Depletion of platelets using an anti-CD41 antibody or anti-thrombocyte serum exacerbated MCT-induced liver injury in C57BL/6 mice, as indicated by an increase in the alanine transaminase (ALT) level, which was associated with hemorrhagic necrosis. Thrombocytosis induced by thrombopoietin (TPO) or the TPO receptor agonist romiplostim (ROM) attenuated MCT-induced liver injury, as evidenced by lower levels of ALT and mRNA encoding matrix metalloproteinase (MMP) 9, and higher levels of mRNA encoding vascular endothelial growth factor receptor (VEGFR) 2 and VEGFR3. The level of activated hepatic platelets was higher in TPO- and ROM-treated mice than in saline-treated mice. Co-culture with a high number of platelets increased the viability of LSECs and their mRNA levels of CD31, VEGFR2, and VEGFR3, and decreased their mRNA level of MMP9. The level of VEGF-A was increased in the culture medium of LSECs co-cultured with platelets. These results indicate that platelets attenuate MCT-induced liver injury by minimizing damage to LSECs.

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

BACKGROUND: One major etiology of hepatic sinusoidal obstruction syndrome (HSOS) in China is the intake of pyrrolizidine alkaloids (PAs). Since PAs-induced HSOS is a rare disease that has not been clearly characterized until now, the aim of this study was to investigate clinical characteristics, CT features, and pathological findings of PA-induced HSOS. METHODS: This retrospective cohort study included 116 patients with PAs-induced HSOS and 68 patients with Budd-Chiari syndrome from Jan 2006 to Sep 2016. We collected medical records of the patients, and reviewed image features of CT, and analyzed pathological findings. RESULTS: Common clinical manifestations of PAs-induced HSOS were abdominal distention (98.26%), ascites (100%), jaundice (52.94%), abdominal pain (36.36%). Abnormal liver function was observed in most of PAs-induced HSOS. On CT scan, common findings included: ascites, hepatomegaly, the thickening of gallbladder wall, pleural effusion, patchy liver enhancement, and heterogeneous hypoattenuation. Most of the patients had a low ascitic total protein (< 25 g/L) and a high SAAG (≥ 11.0 g/L). In acute stage, pathologic features were massive sinusoidal dilatation, sinusoidal congestion, the extravasation of erythrocytes, hepatocellular necrosis, the accumulation of macrophages, the deposition of hemosiderin. In subacute stage, complete loss of pericentral hepatocytes, sinusoidal dilatation, the deposition of pigment granules were observed. CONCLUSIONS: The PAs-induced HSOS patients displayed distinct clinical characteristics, imaging features, and pathological findings, which provided some evidences for the diagnosis of PAs-induced HSOS. TRIAL REGISTRATION: ChiCTR-DRD-17010709.

PAI-1 and protein C as early markers of veno-occlusive disease in patients treated for Wilms tumor.

BACKGROUND: Hepatic veno-occlusive (VOD) disease has been described in hematopoietic stem cell transplantation (HSCT), solid tumors, and acute lymphoblastic leukemia. The incidence of VOD in Wilms tumor (WT) ranges from 1.2% to 8%. The diagnosis of VOD is clinical, and there are no validated laboratory biomarkers. PROCEDURE: We prospectively evaluated the specificity and sensitivity of plasminogen-activator inhibitor-1 (PAI-1) and protein C as diagnostic markers of VOD in WT patients. Fifty patients treated from 2008 to 2016 for WT were eligible. VOD was diagnosed according to modified Seattle criteria and retrospectively reclassified according to the recently published criteria for VOD in pediatric HSCT patients. RESULTS: VOD occurred in 6 of 50 patients (12%) after 20 to 97 days from starting chemotherapy. The average duration of VOD was 10 days (range, 4-13 days). PAI-1 levels were elevated in all VOD patients, while a decrease in protein C levels was observed in 33% of patients with VOD. PAI-1 antigen (Ag) values ≥ 26.4 ng/mL demonstrated high sensitivity and specificity for the clinical diagnosis of VOD with sensitivity 100%, specificity 93%; whereas protein C levels below 34.5% had sensitivity 67%, specificity 100%. Both PAI-1 and protein C had an high negative predictive value: PAI-1 Ag 100%; protein C 95%. CONCLUSIONS: PAI-1 Ag and protein C have good sensitivity and specificity for the diagnosis of VOD in WT patients. Their high negative predictive value can be used in the differential diagnosis of liver toxicity, especially in VOD episodes with absent or delayed hyperbilirubinemia.

Gadoxetic Acid-Enhanced Hepatobiliary-Phase Magnetic Resonance Imaging for Pyrrolizidine Alkaloid-Induced Hepatic Sinusoidal Obstruction Syndrome and Association with Liver Function.

Hepatic sinusoidal obstruction syndrome (HSOS) can be caused by pyrrolizidine alkaloids(PAs)-containing herbals. In this study, the aim of our study was to investigate the imaging features of PAs-induced HSOS on gadoxetic acid-enhanced magnetic resonance imaging (MRI), susceptibility-weighted imaging(SWI) and T2* weighted imaging (T2* WI). We analyzed medical records and MR images of 28 PAs-induced HSOS patients enrolled from Feb, 2013, to Apr, 2017. Abnormal liver function was observed in most of the PAs-induced HSOS patients. Heterogeneity of liver parenchyma in hepatobillary phase (HBP) of gadoxetic acid-enhanced MR scan was observed in 100% of the PAs-induced HSOS patients. Distributional patterns of heterogeneous hypointensity were multifocal distribution (mild) in 4 patients (14.29%), multifocal distribution (severe) in 15 cases (53.57%), and diffuse distribution in 9 patients (32.14%). Hypointense in SWI and T2*WI was observed in the patients of PAs-induced HSOS, and the distribution of hypointense in SWI and T2*WI was similar to that of portal-venous phase of MR scan. The severity of heterogeneous hypointensity scored by volume fraction in hepatobillary phase of gadoxetic acid-enhanced MRI was positively correlated with PT and INR, the severity of hypointensity in HBP was a risk factor of death events. In conclusion: Heterogenous hypointensity of liver parenchyma was an imaging sign of hepatobillary phase in gadoxetic acid-enhanced MRI; thus, it will provide evidences for the diagnosis of PA-induced HSOS.

Monocyte-predominant engraftment, cytokine levels and early transplant-related complications in pediatric hematopoietic stem cell recipients.

Myeloablative conditioning is a well-established procedure that precedes hematopoietic stem cell transplantation (HSCT), particularly in pediatric patients. In the period directly following transplantation, several factors may contribute to complications that lead to the activation or damage of endothelial cells, involved in the pathogenesis of vascular endothelial syndromes (VES). However, to date, sufficiently specific and sensitive diagnostic markers for the various forms of VES have not been identified. This was a retrospective single-center study of patients who underwent allogeneic HSCT. For this cohort of patients, parameters including type of engraftment, donor characteristics, and cytokine production were measured and correlated with a high prevalence of short-term complications after HSCT. The aim of this study was to identify specific parameters useful for improving diagnostics and predicting adverse effects in VES. We confirmed that monocyte-predominant engraftment was related to a higher risk for an early transplant-related complication termed sinusoidal obstruction syndrome (SOS). The increased production of specific cytokines, in particular RANTES, represents a marker associated with prevalent engraftment. In addition, patients undergoing prophylaxis with defibrotide had "classical" engraftment, a common cytokine profile and a lower incidence of life-threatening transplant-related complications. The beneficial effect of defibrotide might be a starting point for developing selective prophylaxis for patients with monocyte engraftment to prevent severe early transplant-related complications.

Hepatic veno-occlusive disease following sirolimus-based immune suppression.

Sirolimus-based graft vs. host disease (GVHD) prophylaxis is associated with higher incidence of veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) after allogeneic hematopoietic cell transplantation (HCT). However, whether the clinical manifestations and prognosis of VOD/SOS differs when diagnosed in the setting of sirolimus-based GVHD prophylaxis is not well studied. To address this question, we examined presenting features and treatment outcome of VOD/SOS cases identified in a large retrospective cohort of consecutive HCT procedures (n = 818 total, sirolimus (SIR)/tacrolimus (TAC) n = 308, and methotrexate (MTX) or mycophenolate mofetil (MMF)/TAC n = 510). In multivariate analysis, sirolimus-based GVHD prophylaxis (p = 0.006, HR 3.33, 1.94-5.7) increased risk for VOD/SOS. A total of 58 patients were clinically diagnosed with VOD/SOS (SIR/TAC 38/308, 12.3%, vs. MTX or MMF/TAC 20/510, 3.9%). VOD/SOS diagnosed following SIR/TAC prophylaxis demonstrated later time of onset (median 39 vs. 26 days; p = 0.005), less severe hyperbilirubinemia (Bili > 2, 65% vs. 90% p = 0.04), lesser degree of weight gain (weight gain > 5%, 52% vs 80%, p = 0.04), and more frequent complete resolution of hepatic injury (79% vs. 55%, p = 0.05). Presenting features and natural history of VOD/SOS in the context of SIR/TAC GVHD prophylaxis differ and thus warrant particular clinical attention to later hepatic injury in these patients.

Risk factors for hepatic veno-occlusive disease caused by Gynura segetum: a retrospective study.

BACKGROUND: Hepatic veno-occlusive disease (HVOD) caused by Gynura segetum has been increasingly reported in China in recent years. The aim of this retrospective study was to identify independent prognostic markers for survival in patients with Gynura segetum-induced HVOD and to evaluate the effect of anticoagulants and transjugular intrahepatic portosystemic shunt (TIPS) on survival rate. METHODS: Clinical data including symptoms, signs, imaging characteristics, laboratory test results, results of liver tissue biopsies, type of treatment during follow-up and clinical outcomes were collected. Univariate, multivariate and time-dependent Cox regression analyses were performed. RESULTS: Survival rates were 91% (95% confidence interval [CI], 82-95%), 64% (95% CI, 53-69%) and 57% (95% CI, 51-65%) at 1, 3 and 60 months, respectively. Total bilirubin, albumin and hepatic encephalopathy were independent prognostic markers of survival. Anticoagulants were administered to 76% of the patients. Among 75 patients treated with anticoagulants, 49 patients (65.3%) were cured, whereas 26 patients (34.7%) died; the cure rate in anticoagulant-treated patients was higher than that of those not treated with anticoagulants (χ2 = 9.129, P = 0.004). Cure rate of the anticoagulation + TIPS treatment group was 64.3%, which was also higher than that of the non-anticoagulation group; however, this was not significantly different (χ2 = 3.938, P = 0.096). CONCLUSIONS: The presence of hepatic encephalopathy, serum bilirubin and albumin levels were major prognostic factors for Gynura segetum-induced HVOD. Anticoagulation therapy significantly increased the cure rate; however, TIPS treatment did not have a beneficial effect on the cure rate.

Comprehensive analysis of serum microRNAs in hepatic sinusoidal obstruction syndrome (SOS) in rats: implication as early phase biomarkers for SOS.

Sinusoidal obstruction syndrome (SOS) is a liver injury caused by clinical chemotherapy, of which pathogenesis is associated with the damage in liver sinusoidal endothelial cells (LSEC). The unavailability of appropriate specific biomarkers for the early diagnosis of SOS may potentially overlook SOS patients. In this study, we sought to find serum microRNAs (miRNAs) as non-invasive biomarkers for investigating SOS in rats. Male Sprague-Dawley rats were orally administered monocrotaline, and then, their livers and sera were collected after 0.25, 0.5, 1, 2, 4, and 7 days. The rats showed a typical SOS phenotype including LSEC damage as early as day 0.25, followed by severe hepatocyte damage on day 2, and developed hepatic fibrosis from days 4 to 7. The miRNA microarray showed that 65 serum miRNAs were increased in their levels on day 0.25, when LSEC damage was observed, while hepatocyte damage was absent. Among the increased serum miRNAs on days 0.25-1, miR-511-3p was enriched in normal LSECs and miR-21-5p was in both LSECs and hepatocytes, suggesting that they were released into blood from the damaged LSECs. The miR-122-5p, miR-192-5p, and miR-101b-3p, which were enriched in hepatocytes, reached the highest levels in serum on day 2, suggesting their utility as indicators for hepatocyte damage. No miRNA showing an increasing trend from days 4 to 7 was found as a biomarker for fibrosis. In conclusion, we found that LSEC-derived miR-21-5p and especially miR-511-3p in serum would serve as early phase biomarkers for SOS in response to LSEC damage.

New insights into sinusoidal obstruction syndrome.

BACKGROUND: Entry criteria included patients who developed sinusoidal obstruction syndrome (SOS) at a single centre from January 2000 to December 2011. Patients who underwent haemopoietic stem cell transplantation or actinomicyn-based chemotherapy for nephroblastoma were selected. The study group comprised five patients with SOS who were compared with a control group of seven patients without SOS. AIM: To study the relationships between endothelial extracellular vesicles (EV) and plasminogen-activator inhibitor type 1(PAI-1) to assess their modification in the early phase of SOS. METHODS: Consecutive blood samples were tested for cell-derived EV, PAI-1 and coagulation parameters. Any statistically significant correlation between all datasets was searched. RESULTS: Antithrombin level and platelet count were statistically significantly reduced in SOS patients, suggesting a consumption status. PAI-1:Ag and PAI-1:act showed an inverse relationship with platelet counts (coef. -0.034, SE = 0.016; P = 0.041 and -0.052, SE = 0.019; P = 0.011 respectively). During follow up, PAI-1:Ag was inversely related to EV CD144+ (coef. -0.261, SE = 0.094; P = 0.007) and antithrombin (coef -0.509, SE = 0.175; P = 0.005). PAI-1:act showed an inverse association with EV CD144+ (coef.-0.251, SE = 0.121; P = 0.043), EV CD31+/CD41+ (coef. -0.004, SE = 0.002; P = 0.026) and antithrombin (coef. -0.470, SE = 0.220; P = 0.038). EV generated by rupture of gap junctions (EV CD144+) were increased in SOS patients and also showed a change over time. CONCLUSION: This study demonstrates the existence of an ongoing procoagulant and hypofibrinolytic status in SOS, indicating a possible role for anticoagulant therapy. Moreover, these findings suggest a role for EV CD 144+, either alone or in combination with PAI-1, as a new biomarker for SOS.

Associations between levels of insulin-like growth factor 1 and sinusoidal obstruction syndrome after allogeneic haematopoietic stem cell transplantation.

Allogeneic myeloablative haematopoietic stem cell transplantation (HSCT) is challenged by severe adverse events, as cytotoxic effects of the conditioning may result in systemic inflammation, leaky epithelial barriers and organ toxicities, contributing to treatment-related morbidity and mortality. We hypothesised that insulin-like growth factor-1 (IGF-1), a mediator of growth and proliferation of various tissues, may attenuate chemotherapy-induced tissue damage after HSCT. We prospectively measured plasma levels of IGF-1 and its binding protein 3 (IGFBP-3) in 41 patients undergoing myeloablative HSCT. IGF-1 and IGFBP-3 levels were inversely correlated with C-reactive protein and interleukin-6 levels post HSCT. In multivariate analyses, low levels of IGF-1 and IGFBP-3 before conditioning were associated with increased risk of developing sinusoidal obstruction syndrome (SOS; OR=5.00 per 1 SDS decrease in IGF-1 (95% CI: 1.45-16.67), P=0.011 and OR=5.00 (1.37-20.00), P=0.015, respectively). Furthermore, low pre-transplant levels of IGF-1 and IGFBP-3 were associated with increased fluid retention during the first 21 days post transplant (OR=7.69 (95% CI: 1.59-33.33), P=0.012, and OR=2.94 (1.03-8.33), P=0.045). These data suggest that high levels of IGF-1 and IGFBP-3 may have a protective effect against fluid retention and SOS, possibly by attenuating systemic inflammation, and may prove useful as predictive biomarkers of SOS.

Púrpura trombótica trombocitopénica inducida por ciclosporina. Estudio de 3 casos / Cyclosporin-induced thrombotic thrombocytopenic purpura. Report of three cases

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Splenomegaly and Its Associations with Genetic Polymorphisms and Treatment Outcome in Colorectal Cancer Patients Treated with Adjuvant FOLFOX.

PURPOSE: Splenomegaly is a clinical surrogate of oxaliplatin-induced sinusoidal obstruction syndrome (SOS). We investigated development of splenomegaly and its association with treatment outcome and genetic polymorphisms following adjuvant 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) in colorectal cancer (CRC) patients. MATERIALS AND METHODS: Splenomegaly was determined by spleen volumetry using computed tomography images obtained before initiation of chemotherapy and after completion of adjuvant FOLFOX in CRC patients. Ten genetic polymorphisms in 4 SOS-related genes (VEGFA, MMP9, NOS3, and GSTP1) were analyzed using DNA from peripheral blood mononuclear cells. RESULTS: Of 124 patients included, increase in spleen size was observed in 109 (87.9%). Median change was 31% (range, -42% to 168%). Patients with splenomegaly had more severe thrombocytopenia compared to patients without splenomegaly during the chemotherapy period (p < 0.0001). The cumulative dose of oxaliplatin and the lowest platelet count during the chemotherapy period were clinical factors associated with splenomegaly. However, no significant associations were found between genetic polymorphisms and development of splenomegaly. Disease-free survival was similar regardless of the development of splenomegaly. CONCLUSION: Splenomegaly was frequently observed in patients receiving adjuvant FOLFOX and resulted in more severe thrombocytopenia but did not influence treatment outcome. Examined genetic polymorphisms did not predict development of splenomegaly.

Sinusoidal obstruction syndrome after allogeneic hematopoietic stem cell transplantation: Incidence, risk factors and outcomes.

This retrospective study was conducted in Japan to determine the incidence, risk factors and outcomes of sinusoidal obstruction syndrome (SOS) after allogeneic hematopoietic stem cell transplantation (HSCT). Among 4290 patients undergoing allogeneic HSCT between 1999 and 2010, 462 were diagnosed with SOS according to the Seattle criteria (cumulative incidence, 10.8%). The cumulative incidence of SOS diagnosed by the modified Seattle criteria was 9.3%. Of 462 patients, 107 met the Baltimore criteria and 168 had severe SOS with renal and/or respiratory failure. The median onset for SOS was 12 days after HSCT (range, -2-30). Overall survival at day 100 was 32% for SOS and 15% for severe SOS. Multivariate analyses showed that significant independent risk factors for SOS were the number of HSCTs, age, performance status, hepatitis C virus-seropositivity, advanced disease status and myeloablative regimen. SOS was highly associated with overall mortality (hazard ratio, 2.09; P<0.001). Our retrospective survey showed that the cumulative incidence of SOS in Japan was 10.8%, similar to that previously reported in Western countries, and that the overall survival of patients who developed SOS was low. Furthermore, several risk factors were identified. Preventive and therapeutic strategies for high-risk SOS patients must be established to improve overall survival.

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.