Abstract A classic physiologic response to systemic hypoxia is the increase in red blood cell production. Hypoxia-inducible factors (HIFs) orchestrate this response by inducing cell-type specific gene expression changes that result in increased erythropoietin (EPO) production in kidney and liver, in enhanced iron uptake and utilization and in adjustments of the bone marrow microenvironment that facilitate erythroid progenitor maturation and proliferation. In particular HIF-2 has emerged as the transcription factor that regulates EPO synthesis in the kidney and liver and plays a critical role in the regulation of intestinal iron uptake. Its key function in the hypoxic regulation of erythropoiesis is underscored by genetic studies in human populations that live at high-altitude and by mutational analysis of patients with familial erythrocytosis. This review provides a perspective on recent insights into HIF-controlled erythropoiesis and iron metabolism, and examines cell types that have EPO-producing capability. Furthermore, the review summarizes clinical syndromes associated with mutations in the O2 -sensing pathway and the genetic changes that occur in high altitude natives. The therapeutic potential of pharmacologic HIF activation for the treatment of anemia is discussed.
Abstract Body fluids contain surprising numbers of cell-derived vesicles which are now thought to contribute to both physiology and pathology. Tools to improve the detection of vesicles are being developed and clinical applications using vesicles for diagnosis, prognosis, and therapy are under investigation. The increased understanding why cells release vesicles, how vesicles play a role in intercellular communication, and how vesicles may concurrently contribute to cellular homeostasis and host defense, reveals a very complex and sophisticated contribution of vesicles to health and disease.
Abstract Hereditary spherocytosis and elliptocytosis are the two most common inherited red cell membrane disorders resulting from mutations in genes encoding various red cell membrane and skeletal proteins. Red cell membrane, a composite structure composed of lipid bilayer linked to spectrin-based membrane skeleton is responsible for the unique features of flexibility and mechanical stability of the cell. Defects in various proteins involved in linking the lipid bilayer to membrane skeleton result in loss in membrane cohesion leading to surface area loss and hereditary spherocytosis while defects in proteins involved in lateral interactions of the spectrin-based skeleton lead to decreased mechanical stability, membrane fragmentation and hereditary elliptocytosis. The disease severity is primarily dependent on the extent of membrane surface area loss. Both these diseases can be readily diagnosed by various laboratory approaches that include red blood cell cytology, flow cytometry, ektacytometry, electrophoresis of the red cell membrane proteins, and mutational analysis of gene encoding red cell membrane proteins.
Abstract Several biomaterials can be obtained from human blood. Some are used for clinical indications requiring a high content in fibrinogen, while others are used because they contain multiple platelet growth factors. Mimicking thrombin-induced physiological events of coagulation leading to fibrino-formation and platelet activation, blood biomaterials have critical advantages of being devoid of tissue necrotic effects and of being biodegradable by body enzymes. Fibrin-based biomaterials, known as fibrin glues or fibrin sealants, have been used for more than 30 years as surgical hemostatic and sealing agents, demonstrating benefits in essentially all surgical fields, including reconstructive plastic surgery and wound treatment. Clinical interest in platelet growth factor-rich biomaterials (often known as platelet gels or platelet-rich-plasma) has emerged more recently. Platelet gels are used in clinical situations to achieve wound healing and repair soft and hard tissues. Applications include the healing of recalcitrant ulcers and burns, and stimulation of osseous tissue regeneration in dentistry, implantology, and maxillofacial and plastic surgery. They were evaluated recently in knee osteoarthritis and for the repair of musculoskeletal tissue lesions in sports medicine. Platelet lysates are now used as a substitute for fetal bovine serum and for ex vivo clinical-scale expansion of stem cells, opening new perspectives in regenerative medicine. We present the scientific rationale that prevailed in the development of blood biomaterials, describe their modes of production and biochemical and functional characteristics, and present clinical applications in regenerative medicine.
Abstract After being a neglected and poorly-understood disorder for many years, there has been a recent explosion of data regarding the complex pathogenesis of myelodysplastic syndromes (MDS). On the therapeutic front, the approval of azacitidine, decitabine, and lenalidomide in the last decade was a major breakthrough. Nonetheless, the responses to these agents are limited and most patients progress within 2 years. Allogeneic stem cell transplantation remains the only potentially curative therapy, but it is associated with significant toxicity and limited efficacy. Lack or loss of response after standard therapies is associated with dismal outcomes. Many unanswered questions remain regarding the optimal use of current therapies including patient selection, response prediction, therapy sequencing and combinations, and management of resistance. It is hoped that the improved understanding of the underpinnings of the complex mechanisms of pathogenesis will be translated into novel therapeutic approaches and better prognostic/predictive tools that would facilitate accurate risk-adaptive therapy.
Abstract Hemophilia A is an X-linked hereditary bleeding disorder due to the deficiency of coagulation factor VIII (FVIII). According to the degree of FVIII deficiency, mild, moderate or severe forms are recognized. Although patients with mild hemophilia A usually bleed excessively only after trauma or surgery, those with severe hemophilia experience frequent episodes of spontaneous or excessive bleeding after minor trauma, particularly into joints and muscles. The modern management of hemophilia began in the 1970s and is actually based upon several plasma-derived or recombinant FVIII products. In addition, the synthetic drug desmopressin can be used to prevent or treat bleeding episodes in patients with mild hemophilia A. Long-term and continuous substitution therapy (prophylaxis), the recommended treatment in severe hemophilia, prevents bleeding and the resultant joint damage. In the last twenty years the high standard of hemophilia care has greatly improved the quality of life of patients and their life expectancy has reached that of the non-hemophilic male population, at least in high-income countries. The most serious and challenging complication of treatment of hemophilia A is the development of inhibitors, which renders FVIII concentrate infusion ineffective and exposes patients to an increased risk of morbidity and mortality. In this narrative review, the actual knowledge on the clinical features and management of patients with hemophilia A is summarized.
Abstract Donor lymphocyte infusion (DLI) using unstimulated leukapheresis is one of the most effective treatment strategies for patients with hematological malignancies; its graft-versus-leukemia effects make it especially effective in chronic myeloid leukemia patients who relapsed after allogeneic stem cell transplantation (allo-HSCT). However, DLI application is limited by the development of graft-versus-host disease and aplasia, and thus cannot be routinely applied for prophylaxis. Therefore, important questions remain to be answered, such as when, and whom to DLI? Recent advances enable DLI using allografts of granulocyte colony-stimulating factor-mobilized peripheral blood progenitor cells; allodepleted donor T cells; and infusions of donor-derived, ex vivo-expanded, CD8+ cytotoxic T lymphocyte, which can decrease relapse and improve transplant outcomes. Preemptive immunotherapy of relapse was also introduced based on the determination of mixed chimerism and minimal residual disease. In this review, we summarize the latest developments in recent strategies that will affect future DLI efficacy — focusing on the disadvantages and advantages of each protocol for the treatment, preemptive therapy, and prophylaxis of relapse.
Abstract Despite that the initial phases of chemotherapy induce disappearance of leukemic cells in many patients with acute myeloid leukemia (AML), the prevention of life-threatening relapses in the post-remission phase remains a significant clinical challenge. Allogeneic bone marrow transplantation, which is available for a minority of patients, efficiently prevents recurrences of leukemia by inducing immune-mediated elimination of leukemic cells, and over the past decades, numerous immunotherapeutic protocols have been developed aiming to mimic the graft-versus-leukemia reaction for the prevention of relapse. Here we review past and present strategies for relapse control with focus on overcoming leukemia-related immunosuppression in AML. We envisage future treatment protocols, in which systemic immune activators, such as vaccines, dendritic cell-based therapies, engineered variants of IL-2, or IL-15, are combined with agents that counter immunosuppression mediated by, e.g., the PD/PDL interaction, CTLA-4, CD200, reactive oxygen species, IDO expression, CXCR4, or the KIR/class I interaction, based on characteristics of the prevailing malignant clone. This combinatorial approach may pave the way for individualized immunotherapy in AML.
Abstract Acute myeloid leukemia (AML) is a molecularly heterogeneous disease. Based on cytogenetics and FISH, AML patients are stratified into three major risk categories: favourable, intermediate and unfavourable. However, prognostic stratification and treatment decision for the intermediate risk category, that mostly comprises AML patients with normal cytogenetics (CN-AML), has been difficult due to the clinical heterogeneity and scarce knowledge of the molecular alterations underlying this large AML subgroup. During the past decade, the identification of several mutations associated with CN-AML has resulted into important advances in the AML field. In this review, we address the biological features of the main mutations associated with CN-AML and the impact of next generation sequencing studies in expanding our knowledge of the molecular landscape of CN-AML. In addition, we outline the prognostic value of mutations for risk stratification of CN-AML patients and discuss the potential of mutations discovery process for developing new molecular targeted therapies.
Abstract Red blood cell research is important for both, the clinical haematology, such as transfusion medicine or anaemia investigations, and the basic research fields like exploring general membrane physiology or rheology. Investigations of red blood cells include a wide spectrum of methodologies ranging from population measurements with a billion cells evaluated simultaneously to single-cell approaches. All methods have a potential for pitfalls, and the comparison of data achieved by different technical approaches requires a consistent set of standards. Here, we give an overview of common mistakes using the most popular methodologies in red blood cell research and how to avoid them. Additionally, we propose a number of standards that we believe will allow for data comparison between the different techniques and different labs. We consider biochemical analysis, flux measurements, flow cytometry, patch-clamp measurements and dynamic fluorescence imaging as well as emerging single-cell techniques, such as the use of optical tweezers and atomic force microscopy.
Abstract The ubiquitin proteasome system (UPS) plays a central role in cellular protein homeostasis through the targeted destruction of damaged/misfolded proteins and regulatory proteins that control critical cellular functions. The UPS comprises a sequential series of enzymatic activities to covalently attach ubiquitin to proteins to target them for degradation through the proteasome. Aberrancies within this system have been associated with transformation and tumourigenesis and thus, the UPS represents an attractive target for the development of anti-cancer therapies. The use of the first-in-class proteasome inhibitor, bortezomib, in the treatment of Plasma Cell Myeloma and Mantle Cell Lymphoma has validated the UPS as a therapeutic target. Following on its success, efforts are focused on the development of second-generation proteasome inhibitors and small molecule inhibitors of other components of the UPS. This review will provide an overview of the UPS and discuss current and novel therapies targeting the UPS.
Abstract Tissue factor pathway inhibitor (TFPI) is the main inhibitor of tissue factor (TF)-mediated coagulation. In atherosclerotic plaques TFPI co-localizes with TF, where it is believed to play an important role in attenuating TF activity. Findings in animal models such as TFPI knockout models and gene transfer models are consistent on the role of TFPI in arterial thrombosis as they reveal an active role for TFPI in attenuating arterial thrombus formation. In addition, ample experimental evidence exists indicating that TFPI has inhibitory effects on both smooth muscle cell migration and proliferation, both which are recognized as important pathological features in atherosclerosis development. Nonetheless, the clinical relevance of these antithrombotic and atheroprotective effects remains unclear. Paradoxically, the majority of clinical studies find increased instead of decreased TFPI antigen and activity levels in atherothrombotic disease, particularly in atherosclerosis and coronary artery disease (CAD). Increased TFPI levels in cardiovascular disease might result from complex interactions with established cardiovascular risk factors, such as hypercholesterolemia, diabetes and smoking. Moreover, it is postulated that increased TFPI levels reflect either the amount of endothelial perturbation and platelet activation, or a compensatory mechanism for the increased procoagulant state observed in cardiovascular disease. In all, the prognostic value of plasma TFPI in cardiovascular disease remains to be established. The current review focuses on TFPI in clinical studies of asymptomatic and symptomatic atherosclerosis, coronary artery disease and ischemic stroke, and discusses potential atheroprotective actions of TFPI.
Abstract Sickle cell disease (SCD) is a genetic disorder characterised by anaemia and “sickling” of red blood cells, leading to chronic haemolytic anaemia, vascular injury, and organ dysfunction. Although children and adults experience many similar symptoms and problems, complications increase with age, leading to early mortality. Hydroxyurea (hydroxycarbamide), the only US Food and Drug Administration-approved treatment, continues to be under-utilised and other treatments available to children are often inaccessible for adults. Haematopoietic stem-cell transplantation is a curative option, but is limited by a lack of donors and concerns for transplant-related toxicities. Although comprehensive programs exist in paediatrics, affected adults may not have access to preventative and comprehensive healthcare because of a lack of providers or care coordination. They are often forced to rely on urgent care, leading to increased healthcare utilisation costs and inappropriate treatment. This problem highlights the importance of primary care during the transition from paediatrics to adulthood.
Abstract MicroRNAs (miRNAs) have become one of the hottest topics in biology over recent years, but remarkably have only been formally recognized for just over 10 years. These endogenously produced short (19–24 nt) non-coding RNAs have introduced an entirely new paradigm in our understanding of gene control and it is now evident that miRNAs play a crucial regulatory role in many, if not all, physiological and pathological processes. In this review we provide an overview of the role and potential clinical utility for miRNAs in hematological malignancies and their function in normal hematopoiesis. Although still in its infancy, the miRNA field has already added much to our understanding of hematological processes, and provides us with novel tools as both biomarkers and therapeutic agents for hematological malignancies.
Abstract Venous thromboembolism (VTE) is the common cause of morbidity and mortality. Vena cava filters (VCF) represent an important alternative to anticoagulation for management of VTE. VCF use has increased dramatically with the availability of retrievable filters. Since indiscriminate use of VCF can be associated with net patient harm, knowledge of the risks and benefits of these devices is essential to optimal evidence-based practice. In this review, we will examine the characteristics of available permanent and optional VCF, their efficacy and safety in management of VTE and discuss appropriate, extended and unsubstantiated indications for VCF use. We will also review the clinical outcomes of VCF in alternative placement sites (supra-renal inferior vena cava and superior vena cava) and in specialized patient populations (bariatric surgery, cancer, etc.), recommendations regarding anticoagulation for prevention of thrombosis as well as recommended follow up for patients with VCF.
Abstract The complex relationship between the inflammatory response and vascular injury and repair is of major importance to the pathogenesis of cardiovascular disease. CRP is not only a strong marker for cardiovascular morbidity but a modulator that suppresses local and systemic thromboregulatory pathways. In the present review we address the question of whether CRP is involved in atherogenesis, in thrombosis, or in both components of the atherothrombotic process. While CRP is present in the atherosclerotic lesion, it is probably not pro-atherogenic and correlates only minimally with atherogenesis. Alas, CRP promotes thrombus formation and vascular occlusion. Thus, CRP is most likely not affecting atheroma build-up but rather the deleterious process of plaque vulnerability and thrombus formation. Dwelling into CRP mechanism of action may lead to the design of new diagnostic modalities that will add to the predictive value of CRP in identifying those patients at high cardiovascular risk. Furthermore, defining the mechanistic domain is the foundation to the cause–effect detection of possible therapeutic interventions to counter CRP morbid effects.
Abstract Two-thirds of patients with multiple myeloma are aged 65 years or more and the prevalence of multiple myeloma in elderly patients is expected to rise in the next future. Patients older than 65 years are usually considered ineligible for transplantation. The introduction of novel agents, such as the immunomodulatory drugs thalidomide and lenalidomide and the proteasome inhibitor bortezomib, combined with conventional chemotherapy, has radically changed the treatment paradigm of elderly patients and improved outcome. A sequential approach, consisting of an induction regimen associated with a high rate of complete response, followed by consolidation/maintenance therapy, induces a profound cytoreduction and delays relapse, thus improving survival. Novel agents associated with reduced-intensity autologous transplant showed to be safe and effective in fit elderly patients. Patients older than 75 years or vulnerable ones are more susceptible to adverse events that negatively affect treatment adherence and outcome. In this setting, less toxic regimens and appropriate dose reductions should be adopted. Here we provide an overview of novel agent-based treatment strategies for elderly patients with multiple myeloma.
Abstract Myeloma bone disease (MBD) is the most visible aspect of plasma cell myeloma (PCM), which is characterized by the displacement of hematopoiesis and the formation of osteolytic bone lesions. The secreted glycoprotein Dickkopf-1 (DKK1), an inhibitor of the Wnt signaling pathway, is broadly expressed in myeloma cells but highly restricted in normal tissues. DKK1 plays a critical role in several aspects of bone biology and actively participates in regulating MBD by inhibiting osteoblasts and by activating osteoclasts. Based on these findings, ongoing research has been targeting DKK1 to find novel therapeutic strategies for MBD, such as DKK1-neutralizing antibodies, proteasome inhibitors, and vaccines. All these strategies have produced encouraging clinical results and consequently, revealed the significance of DKK1 in MBD. This review discusses the recent advances in our understanding of the DKK1 pathway signaling and how DKK1 can be exploited in the therapeutic intervention of MBD.
Abstract The long-term clinical course of acute pulmonary embolism (PE) is complicated by high rates of serious adverse events, both before and after cessation of anticoagulant therapy. These adverse events include recurrent venous thromboembolism, chronic thromboembolic pulmonary hypertension, arterial thrombotic events and increased risk of death, all compared to patients without thromboembolic disease. Several pharmacological options are available that may beneficially influence patients' prognosis. Nonetheless, because of insufficient knowledge of the benefit-to-harm ratio of these pharmacological agents, unambiguous recommendations are scarcely available. This review will cover the epidemiological aspects of the various possible complications in the long-term clinical course of acute PE as well as the latest evidence on preventive strategies. In addition, the unresolved issues regarding frequency, duration and focus of medical follow-up after acute PE are discussed.
Abstract Anti-CD20 monoclonal antibodies (MoAbs), employed in treating CD20+ lymphomas and autoimmune diseases, appear to have broader functions than just eradicating malignant B-cells and decreasing autoantibody production. Rituximab-induced T-cell inactivation, reported both in-vitro and in-vivo , may contribute to the increased risk of T-cell-dependent infections, observed in patients receiving this therapy. T-cell polarization into a suppressive phenotype, often observed in patients receiving rituximab for autoimmune disorders, was reported to be associated with prolonged remissions. Elimination of B-cells serving as antigen-presenting cells, thereby causing impaired T-cell activation, could play a significant role in induction of these changes. Direct binding of rituximab to a CD20dim T-cell population, inducing its depletion, may contribute to the decreased T-cell activation following rituximab therapy. Further investigation of the complex network through which rituximab and new anti-CD20 MoAbs act, would advance the employment of these agents in different clinical settings.