The prothrombin gene variant G20210A but not factor V leiden may be associated with veno-occlusive disease following BMT

Therapeutic Opportunities and Delivery Strategies for Brain Revascularization in Stroke, Neurodegeneration, and Aging

Central nervous system (CNS) diseases, especially acute ischemic events and neurodegenerative disorders, constitute a public health problem with no effective treatments to allow a persistent solution. Failed therapies targeting neuronal recovery have revealed the multifactorial and intricate pathophysiology underlying such CNS disorders as ischemic stroke, Alzheimeŕs disease, amyotrophic lateral sclerosis, vascular Parkisonism, vascular dementia, and aging, in which cerebral microvasculature impairment seems to play a key role. In fact, a reduction in vessel density and cerebral blood flow occurs in these scenarios, contributing to neuronal dysfunction and leading to loss of cognitive function. In this review, we provide an overview of healthy brain microvasculature structure and function in health and the effect of the aforementioned cerebral CNS diseases. We discuss the emerging new therapeutic opportunities, and their delivery approaches, aimed at recovering brain vascularization in this context. SIGNIFICANCE STATEMENT: The lack of effective treatments, mainly focused on neuron recovery, has prompted the search of other therapies to treat cerebral central nervous system diseases. The disruption and degeneration of cerebral microvasculature has been evidenced in neurodegenerative diseases, stroke, and aging, constituting a potential target for restoring vascularization, neuronal functioning, and cognitive capacities by the development of therapeutic pro-angiogenic strategies.

Genetic Predictors for Sinusoidal Obstruction Syndrome-A Systematic Review

Sinusoidal obstruction syndrome (SOS) is a potentially life-threatening complication after hematopoietic stem cell transplantation (HSCT) or antineoplastic treatment without HSCT. Genetic variants were investigated for their association with SOS, but the evidence is inconclusive. We performed a systematic literature review to identify genes, gene variants, and methods of association analyses of genetic markers with SOS. We identified 23 studies after HSCT and 4 studies after antineoplastic treatment without HSCT. One study (4%) performed whole-exome sequencing (WES) and replicated the analysis in an independent cohort, 26 used a candidate-gene approach. Three studies included >200 participants (11%), and six were of high quality (22%). Variants in 34 genes were tested in candidate gene studies after HSCT. Variants in GSTA1 were associated with SOS in three studies, MTHFR in two, and CPS1, CTH, CYP2B6, GSTM1, GSTP1, HFE, and HPSE in one study each. UGT2B10 and LNPK variants were identified in a WES analysis. After exposure to antineoplastic agents without HSCT, variants in six genes were tested and only GSTM1 was associated with SOS. There was a substantial heterogeneity of populations within and between studies. Future research should be based on sufficiently large homogenous samples, adjust for covariates, and replicate findings in independent cohorts.

Role of Pharmacogenetics in Hematopoietic Stem Cell Transplantation Outcome in Children

Hematopoietic stem cell transplantation (HSCT) is an established therapeutic procedure for several congenital and acquired disorders, both malignant and nonmalignant. Despite the great improvements in HSCT clinical practices over the last few decades, complications, such as graft vs. host disease (GVHD) and sinusoidal obstructive syndrome (SOS), are still largely unpredictable and remain the major causes of morbidity and mortality. Both donor and patient genetic background might influence the success of bone marrow transplantation and could at least partially explain the inter-individual variability in HSCT outcome. This review summarizes some of the recent studies on candidate gene polymorphisms in HSCT, with particular reference to pediatric cohorts. The interest is especially focused on pharmacogenetic variants affecting myeloablative and immunosuppressive drugs, although genetic traits involved in SOS susceptibility and transplant-related mortality are also reviewed.

Genome-wide single-nucleotide polymorphism analysis revealed SUFU suppression of acute graft-versus-host disease through downregulation of HLA-DR expression in recipient dendritic cells

Graft-versus-host disease (GVHD) is a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). To identify recipient risk factors, a genome-wide study was performed including 481,820 single-nucleotide polymorphisms (SNPs). Two GVHD susceptibility loci (rs17114803 and rs17114808) within the SUFU gene were identified in the discovery cohort (p = 2.85 × 10⁻⁵). The incidence of acute GVHD among patients homozygous for CC at SUFU rs17114808 was 69%, which was significantly higher than the 8% rate observed in CT heterozygous patients (p = 0.0002). In an independent validation cohort of 100 patients, 50% of the patients with the CC genotype developed GVHD compared to 8% of the patients with either CT or TT genotype (p = 0.01). In comparison to CC dendritic cells, those from CT expressed higher levels of SUFU mRNA and protein, had lower levels of surface HLA-DR, and induced less allogeneic mixed leukocyte response (MLR). Ectopic expression of SUFU in THP-1 derived DCs reduced HLA-DR expression and suppressed MLR, whereas silencing of SUFU enhanced HLA-DR expression and increased MLR. Thus our findings provide novel evidence that recipient SUFU germline polymorphism is associated with acute GVHD and is a novel molecular target for GVHD prevention and treatment.

Relation of Soluble Endothelial Protein C Receptor and Cytokines After Allogeneic Hematopoietic Stem Cell Transplantation

Aim: The objective of this study was to elucidate the effects of tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), interleukin 2 (IL-2), interleukin 6 (IL-6), and interleukin 8 (IL-8) on the expression of soluble endothelial protein C receptor (sEPCR) in the pathogenesis of thrombotic complications after hematopoietic stem cell transplantation (HSCT).

Methods: The relationship between plasma concentrations of proinflammatory cytokines (TNF-α, IL-1β, IL-2, IL-6, and IL-8) and sEPCR was evaluated in 32 consecutive allogeneic hematopoietic stem cell—transplanted patients prior to conditioning regimen and randomly once between +5 and +30 days after transplantation and compared these results with 20 healthy controls.

Results: Soluble endothelial protein C receptor levels did not indicate any significant difference between pre- and posttransplantation period, and sEPCR levels showed a significantly negative correlation between IL-6 and IL-8 (sEPCR and IL-6, r = —.43, P < .01; sEPCR and IL-8, r = —.57, P < .01). There was no correlation between sEPCR levels and TNF-α, IL-1β, or IL-2 (sEPCR and TNF-α, r = —.13, P > .05; sEPCR and IL-1β, r = —.1, P ≥ .05; sEPCR and IL-2, r = —.07, P > .05).

Conclusions: Our results suggest that the production of sEPCR was not affected by allogeneic HSCT. Soluble endothelial protein C receptor did not show any positive correlation between these proinflammatory cytokines (TNF-α, IL-1β, IL-2, IL-6, and IL-8), on the contrary a significantly negative correlation was determined between sEPCR and either IL-6 or IL-8. This negative correlation may be a protective mechanism in the pathway of protein C activation.

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.

Genomic screening and complications of hematopoietic stem cell transplantation: has the time come?

The occurrence of toxic complications following hematopoietic stem cell transplantation (HSCT) is highly variable and dependent on a multitude of host, donor, and treatment factors. The increasingly broad indications for HSCT and the need to provide this treatment option to older and/or more debilitated patients emphasizes the importance of refining our methods of predicting and ameliorating these toxicities. Late complications (occurring after day 100) also pose a threat to quality of life after HSCT. Genetic polymorphisms in key molecular pathways in the host are likely to contribute significantly to the observed variability in the development HSCT-associated complications. Hepatic veno-occlusive disease and acute lung injury, two of the most serious organ toxicities that occur, represent useful paradigms for the identification of genetic polymorphisms in enzyme systems that modulate local and systemic responses to oxidant stress during transplant conditioning therapy. Ongoing studies in this area are providing clues to the prevention of adverse clinical outcomes based on the genetic milieu. This review of studies in HSCT that explore genetic risk factors for transplant complications indicates that significant progress is being made in this rapidly evolving area. However, further large-scale clinical and translational studies are needed before genomic screening can be widely used to individualize treatment.

Genetic variation and hematopoietic stem cell transplantation: expansion of the paradigm

Genetic variation has been the mainstay of hematopoietic stem cell transplantation since the first transplants were attempted. A significant expansion of genetic knowledge is under way, as the draft sequence of the human genome is annotated. Hematopoietic stem cell transplantation is a field that will greatly benefit from this new knowledge, but the manner in which it is applied is daunting. Variation within key molecules related to hematopoietic stem cell transplant in combination with the current knowledge of human leukocyte antigen variation will serve to improve donor-recipient matches and clinical outcome.

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.

Portal vein thrombosis after hematopoietic cell transplantation: frequency, treatment and outcome

Patients who develop veno-occlusive disease (VOD) of the liver may have low plasma levels of the natural anticoagulants protein C and antithrombin III, but large vessel thromboses are not commonly reported in these patients. We reviewed the records of 1847 consecutive patients for evidence of portal vein thrombosis. Eight patients (0.4%) developed portal vein thrombosis (PVT) at a median of day +28 (range 3-58). All patients had clinical evidence of VOD with ascites, a median total serum bilirubin 11.9 mg/dl, and median weight gain from baseline of 7.9%. Median plasma levels of antithrombin III and protein C were low (36% and 21%, respectively). Four patients with PVT died of severe VOD and multi-organ failure, but PVT did not contribute to death. We conclude that PVT is a rare complication of hematopoietic cell transplant and is associated with hepatic VOD. We speculate that PVT resulted from diminished portal venous flow (related to hepatic sinusoidal obstruction to blood flow) and a hypercoagulable state (related to low circulating antithrombin III and protein C levels). Prognosis depended on the severity of the underlying VOD and not PVT per se, suggesting that treatments directed solely toward dissolution of portal vein thrombi should be used with caution in this setting.