Heparanase, a β-D-endoglucuronidase abundant in platelets that was discovered 30 years ago, is an enzyme that cleaves heparan sulfate side chains on the cell surface and in the extracellular matrix. It was later recognized as being a pro-inflammatory and pro-metastatic protein. We had earlier demonstrated that heparanase may also affect the hemostatic system in a non-enzymatic manner. We had shown that heparanase up-regulated the expression of the blood coagulation initiator tissue factor (TF) and interacted with the tissue factor pathway inhibitor (TFPI) on the cell surface membrane of endothelial and tumor cells, leading to dissociation of TFPI and resulting in increased cell surface coagulation activity. Moreover, we have demonstrated that heparanase directly enhanced TF activity which led to increased factor Xa production and subsequent activation of the coagulation system. Recently, heparanase inhibitory peptides derived of TFPI-2 were demonstrated by us to inhibit heparanase procoagulant activity and attenuate sepsis in mouse models.
Thrombotic microangiopathies (TMAs) comprise a group of distinct disorders characterized by microangiopathic hemolytic anemia, thrombocytopenia, and microvascular thrombosis. For many years distinction between these TMAs, especially between thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS), remained purely clinical and hard to make. Recent discoveries shed light on different pathogenesis of TTP and HUS. Ultra-large von Willebrand factor (UL-VWF) platelet thrombi, resulting from the deficiency of cleavage protease which is now known as ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), were found to cause TTP pathology, while Shiga toxins or abnormalities in regulation of the complement system causes microangiopathy and thrombosis in HUS. TMAs may appear in various conditions such as pregnancy, inflammation, malignancy, or exposure to drugs. These conditions might cause acquired TTP, HUS, or other TMAs, or might be a trigger in individuals with genetic predisposition to ADAMTS-13 or complement factor H deficiency. Differentiation between these TMAs is highly important for urgent initiation of appropriate therapy. Measurement of ADAMTS-13 activity and anti-ADAMTS-13 antibody levels may advance this differentiation resulting in accurate diagnosis. Additionally, assessment of ADAMTS-13 levels can be a tool for monitoring treatment efficacy and relapse risk, allowing consideration of therapy addition or change. In the past few years, great improvements in ADAMTS-13 assays have been made, and tests with increased sensitivity, specificity, reproducibility, and shorter turnaround time are now available. These new assays enable ADAMTS-13 measurement in routine clinical diagnostic laboratories, which may ultimately result in improvement of TMA management.
Pregnancy is a physiological hypercoagulable state, preparing the mother for the hemostatic challenge of delivery. However, this is associated with an increased risk of venous thrombosis and placenta-mediated complications, which present major challenges for mother and fetus. Although these conditions are heterogeneous in their pathophysiology, hereditary and acquired thrombophilia has been associated with recurrent pregnancy loss and gestational vascular complications, such as early-onset pre-eclampsia and placental abruption. Prevention of such placenta-mediated complications, which collectively complicate up to 15% of pregnancies, is a major issue for women’s health. Prospective interventional studies stratified by current knowledge of pathophysiological mechanisms related to placental and systemic hemostatic alterations will impact on the management of pregnancies at risk of these complications.
Venous thromboembolism (VTE), the third most frequent acute cardiovascular syndrome, may cause life-threatening complications and imposes a substantial socio-economic burden. During the past years, several landmark trials paved the way towards novel strategies in acute and long-term management of patients with acute pulmonary embolism (PE). Risk stratification is increasingly recognized as a central cornerstone for an adequate diagnostic and therapeutic management of the highly heterogeneous population of patients with acute PE. Recently published European Guidelines emphasize the importance of clinical prediction rules in combination with imaging procedures (assessment of right ventricular function) and laboratory biomarkers (indicative of myocardial stress or injury) for identification of normotensive PE patients at intermediate risk for an adverse short-term outcome. In this patient group, systemic full-dose thrombolysis was associated with a significantly increased risk of intracranial bleeding, a complication which discourages its clinical application unless hemodynamic decompensation occurs. A large-scale clinical trial program evaluating new oral anticoagulants in the initial and long-term treatment of venous thromboembolism showed at least comparable efficacy and presumably increased safety of these drugs compared to the current standard treatment. Research is continuing on catheter-directed, ultrasound-assisted, local, low-dose thrombolysis in the management of intermediate-risk PE.
The hematopoietic stem cell (HSC) is a unique cell positioned highest in the hematopoietic hierarchical system. The HSC has the ability to stay in quiescence, to self-renew, or to differentiate and generate all lineages of blood cells. The path to be actualized is influenced by signals that derive from the cell’s microenvironment, which activate molecular pathways inside the cell. Signaling pathways are commonly organized through inducible protein–protein interactions, mediated by adaptor proteins that link activated receptors to cytoplasmic effectors. This review will focus on the signaling molecules and how they work in concert to determine the HSC’s fate.
Extracellular vesicles (EVs), comprised of exosomes, microparticles, apoptotic bodies, and other microvesicles, are shed from a variety of cells upon cell activation or apoptosis. EVs promote clot formation, mediate pro-inflammatory processes, transfer proteins and miRNA to cells, and induce cell signaling that regulates cell differentiation, proliferation, migration, invasion, and apoptosis. This paper will review the contribution of EVs in hematological disorders, including hemoglobinopathies (sicklecell disease, thalassemia), paroxysmal nocturnal hemoglobinuria, and hematological malignancies (lymphomas, myelomas, and acute and chronic leukemias).
Kallmann syndrome is named after Franz Joseph Kallmann, a German-born psychiatrist who described in 1944 twelve subjects from three families who presented with a syndrome of missed puberty, anosmia, and color blindness. Yet, several other eponyms for the same syndrome can be found in the literature. Despite the fact that Kallmann syndrome is the most recognized eponym, very little is known about the man for whom the syndrome is named. A biographical note on Franz Joseph Kallmann and his historical context is presented.
Jewish medical ethics is arguably the oldest recorded system of bioethics still in use. It should be of interest to practicing nephrologists because of its influence on the ethical systems of Christianity, Islam, and Western secular society; because of the extensive written documentation of rabbinical response in addressing a broad range of bioethical dilemmas; and in understanding the values of patients who choose to adhere to religious Jewish law. The goal of this review is to provide a brief overview of the basic principles underlying mainstream traditional Jewish medical ethics, apply them to common clinical scenarios experienced in nephrology practice, and contrast them with that of secular medical ethics.
A physician is a valued member of society on whom many individuals rely for both professional advice and support during times where they may feel to be at a disadvantage, whether it be physically or mentally. An issue on the rise today concerns the population of smokers in our society. Many are coming to share the opinion that physicians should not provide treatments for smokers. Some of the opinions are based on the claim that smokers are morally responsible for their medical conditions. But, providing care in a fair manner includes not treating differently those who suffer from addiction. Moreover, it is important to recognize that allocating medical resources based on moral responsibility will undermine the physician–patient relationship which is necessary for the practice of medicine. Many countries have codes and policies that physicians must legally follow in terms of providing treatments. With acceptance of the fact that the patient may be unable to execute the decisions made by the physician, it is the legal duty of the physician to provide care and not abandon the patient. An analysis of the many policies around the world brings forward certain changes that must be made in order to make sure that physicians fulfil their legal duty, which is to provide care. As such, this article looks into the existing ethical dilemma in treating smokers around the world, with a review of some policies that will guide our approach in this matter.
The history of medicine has been an intriguing topic for both authors. The modern relevance of past discoveries led both authors to take a closer look at the lives and contributions of persecuted physicians. The Jewish physicians who died in the Holocaust stand out as a stark example of those who merit being remembered. Many made important contributions to medicine which remain relevant to this day. Hence, this paper reviews the lives and important contributions of two persecuted Jewish physicians: Arthur Kessler (1903–2000) and Bronislawa Fejgin (1883–1943).
