Plasma levels of D-dimer and circulating endothelial adhesion molecules in veno-occlusive disease of the liver following allogeneic bone marrow transplantation

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.

Prediction of veno-occlusive disease using biomarkers of endothelial injury

Predicting the development of veno-occlusive disease (VOD) of the liver remains challenging. We hypothesized that biomarkers of endothelial injury in myeloablative allogeneic transplantation recipients could predict VOD occurrence. We evaluated 4 biomarkers-von Willebrand Factor (vWF), thrombomodulin, E-selectin, and soluble intercellular adhesion molecule-1 (sICAM-1)-weekly in the peritransplantation period in an attempt to predict VOD. In the patients who received sirolimus, vWF, thrombomodulin, and sICAM-1 levels were significantly elevated in patients with VOD compared with those without VOD on day -1 (P <or= .035), day +7 (P <or= .0001), and day +14 (P <or= .004). E-selectin was predictive on day +7 (P = .007). Levels of vWF >or=1400 IU/mL and thrombomodulin >or=100 ng/mL on day +7 were both 100% sensitive and 100% specific in predicting VOD. These biomarkers were informative when adjusted for other risk factors for VOD in regression analysis. Among patients not receiving sirolimus, biomarkers of endothelial injury were not informative. We conclude that vWF, thrombomodulin, and sICAM-1 elevations before and early after transplantation may be useful in predicting VOD in patients receiving sirolimus.

Decreased incidence of hepatic veno-occlusive disease and fewer hemostatic derangements associated with intravenous busulfan vs oral busulfan in adults conditioned with busulfan + cyclophosphamide for allogeneic bone marrow transplantation

We investigated the occurrence of hepatic veno-occlusive disease (VOD) after allogeneic bone marrow transplantation (BMT) in 241 adults conditioned with busulfan + cyclophosphamide at a single institute and retrospectively compared 186 patients who received oral busulfan (O-Bu group) with 55 patients who received intravenous busulfan (I-Bu group). Various hemostatic parameters were determined at baseline and on days 0, 7, 14, and 21. Hepatic VOD occurred in 41.7% of the O-Bu group and in 18.5% of the I-Bu group. Multivariate analysis revealed that the I-Bu group had significantly decreased risk of VOD compared to the O-Bu group [p=0.006, odds ratio: (OR) 0.345]. Eleven patients in the O-Bu group and none of the I-Bu group developed severe VOD. A repeated measures analysis of variance (ANOVA) with a between-subjects factor revealed significant differences in post-transplant levels of antithrombin III, tissue plasminogen activator (tPA), plasminogen activator inhibitor 1 (PAI-1), and D-dimer according to the occurrence of VOD. The level of antithrombin III was significantly lower, whereas the level of D-dimer was significantly higher, in the O-Bu group than in the I-Bu group. These findings show that, in adults conditioned with busulfan + cyclophosphamide, intravenous busulfan was associated with significantly decreased incidence of VOD and fewer hemostatic derangements after allogeneic BMT compared to oral busulfan.

Hepatic veno-occlusive disease: pathogenesis, diagnosis and treatment

Hepatic veno-occlusive disease (VOD) is one of the most serious complications following hematopoietic stem cell transplantation (SCT) and is associated with a very high mortality in its severe form. This review outlines the pathogenesis and clinical features of VOD, with an emphasis on endothelial cell injury and risk factors. The current status and future directions of research for both prophylaxis and treatment are also discussed.

Markers of endothelial function in pediatric stem cell transplantation for acute leukemia

BACKGROUND

Endothelial cells and leukocytes intimately interact in inflammation and coagulation processes, so that dysregulation of their function may lead to both cellular damage and thrombosis, which may occur as complications of bone marrow transplantation (BMT). Partially conflicting evidence about endothelial markers and their relationships with clinical complications after BMT has been reported in the literature. Since almost all studies were carried out in adults, we evaluated some recent available markers of endothelial cell function in pediatric patients undergoing stem cell transplantation (SCT) for acute leukemia.

PROCEDURE

We studied the variation in circulating serum endothelial-selectin (ES), leukocyte-selectin (LS), thrombomodulin (TM), von Willebrand factor (vWF), nitrate + nitrite (NO(2) (-)/NO(3) (-)), endothelin-1 (EN), and tissue factor (TF) in 21 pediatric patients undergoing SCT for acute leukemia.

RESULTS

ES and LS significantly lowered following SCT and returned to pre-SCT levels 4 weeks after the procedure. NO(2) (-)/NO(3) (-) markedly increased following SCT. Also, TM and vWF increased, although such changes did not reach statistical significance. EN and TF did not appreciably change. A strong correlation was observed between white blood cell (WBC) count and both ES and LS, as well as between such selectins. TM significantly correlated with both selectins and NO(2) (-)/NO(3) (-). The pre-conditioning levels of TM and vWF in patients undergoing major complications, considered altogether, were significantly lower and higher, respectively, than in uncomplicated patients. NO(2) (-)/NO(3) (-) levels 3 and 4 weeks post-SCT were significantly lower in patients suffering from veno occlusive disease. Both selectins were significantly higher in allo- than in auto-transplanted patients 4 weeks after SCT.

CONCLUSIONS

Our data support the hypothesis of severe endothelial damage after conditioning and SCT, particularly allogeneic. However, the increase in TM, which has strong anticoagulant properties, and metabolites of NO, involved also in protective actions, may reflect regeneration of the anti-thrombotic endothelial function. This could take place after transitory functional impairment, rather than pure endothelial damage.

Avoiding hepatic veno-occlusive disease: what do we know and where are we going?

Hepatic venocclusive disease (VOD) is a common toxicity associated with myeloablative chemotherapy or chemoradiotherapy used to prepare patients for stem cell transplantation. A sizable proportion of patients who develop VOD die. It is clear that injury to endothelial cells and hepatocytes in zone 3 of the liver acinus is the initial event in the pathogenesis of VOD. What are less clear are the mechanisms of injury and whether this knowledge can be exploited. This manuscript will briefly review some recent data and discuss how that information has influenced clinical practice.

Veno-occlusive disease of the liver

The success of high-dose cytoreductive strategies depends not only on antitumor activity but also on the tolerability of treatment. Although advances in supportive care have significantly reduced mortality due to infection and hemorrhage, regimen-related toxicities remain problematic. Hepatic veno-occlusive disease (VOD) is the most serious regimen-related toxicity after high-dose cytoreductive therapy. Risk factors for VOD are well established, but the biology of the syndrome remains poorly understood. Unfortunately, no pharmacologic approaches that clearly prevent or treat VOD have been identified. A better understanding of the pathogenesis of VOD will lead to more effective prevention and treatment strategies.