defibrotide and Syndrome

Endothelial cells are unique multifunctional cells with basal and inducible metabolic and synthetic functions. Various stimuli can induce physiological or pathological changes in endothelial cell biology. Hematopoietic stem cell transplantation (HSCT) requires high-dose irradiation and/or chemotherapy and is associated with increased risk of bacterial infections and immune reactions. These factors can affect endothelial cells. This review provides an overview of the effects of HSCT on endothelial cells, based on findings observed in cultured cells as well as in patients. We first describe to what extent irradiation and chemotherapy constitute direct and indirect triggers for endothelial cell activation and injury. Then, we highlight the role of the endothelium in several complications of HSCT, including capillary leak syndrome, engraftment syndrome, transplant-associated microangiopathy, graft-versus-host disease, and diffuse alveolar hemorrhages. We also analyze in detail available data on sinusoidal obstruction syndrome, previously known as veno-occlusive disease of the liver, where liver sinusoidal endothelial cells are first injured and eventually lead to sinusoid occlusion and liver cell damage. Finally, we open the question of the possible contribution of endothelial damage to cardiovascular events occurring long after HSCT.

Topics: Angiogenic Proteins; Animals; Anticoagulants; Bone Marrow Transplantation; Capillary Leak Syndrome; Cardiovascular Diseases; Cell Adhesion Molecules; Cell-Derived Microparticles; Endothelium, Vascular; Fever; Graft vs Host Disease; Hematologic Diseases; Hematopoietic Stem Cell Transplantation; Hepatic Veno-Occlusive Disease; Humans; Immunosuppressive Agents; Inflammation; Nitric Oxide; Polydeoxyribonucleotides; Pulmonary Veno-Occlusive Disease; Radiation Injuries; Syndrome; Thrombotic Microangiopathies; Transplantation Conditioning

Each year in the US, more than 10 000 patients benefit from allogeneic haematopoietic stem cell transplantation (HSCT), a modality that offers an excellent chance of eradicating malignancy but confers a higher risk of treatment-related mortality. An uncommon but devastating consequence of HSCT is transplantation-associated thrombotic microangiopathy (TA-TMA). The incidence of TA-TMA ranges from 0.5% to 76%, with a mortality rate of 60-90% despite treatment. Although there appears to be a consistent treatment approach to idiopathic thrombotic thrombocytopenic purpura (TTP) using plasma exchange, corticosteroids and rituximab, the treatment strategies for TA-TMA are perplexing, in part, because the literature regarding this complex condition does not provide true consensus for incidence, aetiology, diagnostic criteria, classification and optimal therapy. The classic definition of idiopathic TTP includes schistocytes on the peripheral blood smear, thrombocytopenia and increased serum lactate dehydrogenase. Classic idiopathic TTP has been attributed to deficient activity of the metalloproteinase responsible for cleaving ultra-large von Willebrand factor multimers. This protease is a member of the 'a disintegrin and metalloprotease with thrombospondin type 1 motif' family and is subsequently named ADAMTS-13. Severely deficient ADAMTS-13 activity (<5% of normal) is associated with idiopathic TTP in 33-100% of patients. In constrast to the pathophysiology of idiopathic TTP, patients with TA-TMA have >5% ADAMTS-13 serum activity. These data may explain why plasma exchange, a standard treatment modality for idiopathic TTP that restores ADAMTS-13 activity, is not effective in TA-TMA. TA-TMA has a multifactorial aetiology of endothelial damage induced by intensive conditioning therapy, irradiation, immunosuppressants, infection and graft-versus-host disease. Treatment consists of substituting calcineurin inhibitors with an alternative immunosuppressive agent that possesses another mode of action. One candidate may be daclizumab, especially in those with mild to moderate TMA. Rituximab therapy or the addition of defibrotide may also be beneficial. In general, plasma exchange is not recommended.

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal, Murine-Derived; Daclizumab; Hematopoietic Stem Cell Transplantation; Humans; Immunoglobulin G; Microcirculation; Plasma Exchange; Polydeoxyribonucleotides; Prognosis; Risk Factors; Rituximab; Syndrome; Thrombosis

We report a case of administration compassionate use defibrotide in a 13-year-old girl with Sinusoidal Obstructive Syndrome and thrombocytopenia, also known as Hepatopathy--Thrombocytopenia Syndrome (HTS) during chemotherapy for Wilms' tumor.

Topics: Adolescent; Chemical and Drug Induced Liver Injury; Compassionate Use Trials; Dactinomycin; Female; Humans; Polydeoxyribonucleotides; Syndrome; Thrombocytopenia; Wilms Tumor

Hepatic veno-occlusive disease is a clinical syndrome characterized by hepatomegaly, ascites, weight gain and jaundice, due to sinusoidal congestion which can be caused by alkaloid ingestion, but the most frequent cause is haematopoietic stem cell transplantation (STC) and is also seen after solid organ transplantation. The incidence of veno occlusive disease (VOD) after STC ranges from 0 to 70%, but is decreasing. Survival is good when VOD is a mild form, but when it is severe and associated with an increase of hepatic venous pressure gradient > 20 mmHg, and mortality is about 90%. Prevention remains the best therapeutic strategy, by using non-myeloablative conditioning regimens before STC. Prophylactic administration of ursodeoxycholic acid, being an antioxidant and antiapoptotic agent, can have some benefit in reducing overall mortality. Defibrotide, which has pro-fibrinolytic and antithrombotic properties, is the most effective therapy; decompression of the sinusoids by a transjugular intrahepatic portosystemic shunt (TIPS) can be tried, especially to treat VOD after liver transplantation and when multiorgan failure (MOF) is not present. Liver transplantation can be the last option, but can not be considered a standard rescue therapy, because usually the concomitant presence of multiorgan failure contraindicates this procedure.

Topics: Biopsy; Hepatic Veno-Occlusive Disease; Humans; Liver; Liver Transplantation; Polydeoxyribonucleotides; Portasystemic Shunt, Surgical; Risk Factors; Syndrome; Treatment Outcome

Topics: Aged; Female; Fibrinolytic Agents; Humans; Male; Middle Aged; Phlebitis; Polydeoxyribonucleotides; Skin Diseases; Syndrome; Varicose Ulcer