Adhesion Molecules in Normal Hematopoiesis
Victor R. Preedy in Adhesion Molecules, 2010
Th e role of adhesion molecules in migration and activation of mature cells from peripheral blood has been extensively studied. Nevertheless, only recently is there accumulating evidence that they play a key role in the physiological control of the fate, migration and homing of hematopoietic stem cells. In addition, compared to their normal counterparts, leukemic stem cells and progenitors have a distinct expression profi le of adhesion molecules, which mediate the interaction with the bone marrow microenvironment, thus contributing to survival advantage. In the distinct Acute Myelogenous Leukemia subtype termed Acute Promyelocytic Leukemia, the modulation of adhesion molecules by diff erentiating agents such as the all-trans retinoic acid (ATRA) and arsenic trioxide constitute the molecular basis of diff erentiation syndrome, a life-threatening complication of the treatment. In the present chapter, we review some key aspects of the role of adhesion molecules in normal and malignant hematopoiesis.
Vitamins
Frank A. Barile in Barile’s Clinical Toxicology, 2019
Vitamins, as the Latin derivation of the name implies, are essential for the maintenance of adequate health and life. They are diverse organic substances provided in small quantities in the diet and are found in a variety of chemical forms and structures. Vitamins have assorted essential biochemical roles in contributing to the maintenance of health and have unique therapeutic places in the treatment of related disorders. Vitamin A, and its derivatives, is essential for proper maintenance of visual acuity, dental development, skeletal muscle and bone growth, corticosteroid synthesis, and embryonic development and reproduction. Thiamine is essential for normal aerobic metabolism and tissue development, proper transmission of nerve impulses, and synthesis of acetylcholine. It combines with adenosine triphosphate to form thiamine pyrophosphate, the active form of thiamine. Pteroylglutamic acid is found in leafy vegetables, organ meats, and yeast. Physiologically, folic acid is required for nucleoprotein synthesis and the maintenance of hematopoiesis.
Introduction to Blood Cancers
Tariq I. Mughal, Tariq Mughal, John Goldman, John M. Goldman, Sabena T. Mughal, Sabena Mughal in Understanding Leukemias, Lymphomas and Myelomas, 2013
The simplest definition of hematological cancers is that they are cancers which arise from a single blood cell. Since all blood cells are produced by a process called hematopoiesis (“heme” comes from the Greek word haema or “ α ιc μα” for blood and “ π ο í ησιc ” or poiesis means creation or formation), cancers such as leukemias, lymphomas, and myelomas are often referred to as blood cancers. The cancer type usually refers to the organ or the specific type of cell where cancer originates. To distinguish blood cancer from other forms of cancers, they are sometimes referred to as “liquid tumors” since they typically do not form lumps or masses (“tumors”). In contrast, cancers arising from all other cells, which typically form masses, are called “solid tumors.”
Clonality Analysis of Hematopoiesis and Thrombopoietin Levels in Patients with Essential Thrombocythemia
Published in Leukemia & Lymphoma, 1998
N. El-Kassar, G. Hetet, J. Brière, B. Grandchamp
Essential thrombocythemia (ET) is a myeloproliferative disorder, characterized by sustained thrombocytosis. Diagnosis requires the elimination of all known causes of thrombocytosis. ET is believed to be a clonal disorder, and we investigated the frequency of a clonal hematopoiesis in this disease with the aim of using this as a positive diagnostic criterion. However, a non-random inactivation pattern can be encountered in normal females which mimics clonal hematopoiesis. In addition, the percentage of normal females with skewed lyonization seems higher using techniques based on the difference in DNA methylation, compared to G6PD enzyme polymorphism. Recently, new techniques based on transcript analysis have been developed. We report here the results of clonality studies of hematopoiesis in 53 ET patients using two different techniques based on DNA and RNA polymorphisms, and T-lymphocytes as a control tissue of lyonization. The majority of ET patients showed monoclonal hematopoiesis in the presence of polyclonality of T-lymphocytes. Because all ET patients did not show the same clonal pattern of hematopoiesis, we searched for inappropriate secretion of thrombopoietin (TPO) in patients with polyclonal disease. This assay was performed in 48 patients, of whom 9 showed polyclonal hematopoiesis and 27 monoclonal hematopoiesis. We found no difference in TPO levels between ET patients and normal controls, nor between patients with polyclonal hematopoiesis and those with monoclonal hematopoiesis. Our results confirm the high frequency of monoclonal hematopoiesis in ET, the usefulness of RNA markers, and the possibility of using T-lymphocytes as a control tissue for X-chromosome inactivation patterns. On the other hand, TPO levels are not decreased even in ET patients with high platelet counts, suggesting an increased production or decreased clearance of TPO in this disease.
Four stages of hepatic hematopoiesis in human embryos and fetuses
Published in The Journal of Maternal-Fetal & Neonatal Medicine, 2018
D. Fanni, F. Angotzi, F. Lai, C. Gerosa, G. Senes, V. Fanos, G. Faa
The liver is a major hematopoietic organ during embryonic and fetal development in humans. Its hematopoietic activity starts during the first weeks of gestation and continues until birth. During this period the liver is colonized by undifferentiated hematopoietic stem cells (HSCs) that gradually differentiate and once mature, enter the circulatory system through the hepatic sinusoids, this process is called hepatic hematopoiesis. The morphology of hepatic hematopoiesis, has been studied in humans through the years, and led to a characterization of all the cell types that make up these phenomena. Studies on murine models also helped to describe the extent of hepatic hematopoiesis at different gestational ages. Using this knowledge, we attempted to describe how hepatic hematopoiesis morphologically evolves as gestation progresses, in human embryos and fetuses. Thus, we observed a total of 32 tissue specimens obtained from the livers of embryos and fetuses at different gestational ages. Basing our observations on the four stages of liver hematopoiesis identified by Sasaki and Sonoda in mice, we also described four consecutive stages of liver hematopoiesis in humans, which resulted to be highly similar to those described in murine models.
The peptide network regulated by angiotensin converting enzyme (ACE) in hematopoiesis
Published in Cell Cycle, 2011
Xiao Z. Shen, Kenneth E. Bernstein
The concept of a local bone marrow renin-angiotensin system (RAS) has been introduced and accumulating evidence suggests that the local RAS is actively involved in hematopoiesis. Angiotensin converting enzyme (ACE) is a key player in the RAS and makes the final effector angiotensin II. Besides angiotensin II, ACE also regulates a panel of bioactive peptides, such as substance P, Ac-SDKP and angiotensin 1-7. These peptides have also been individually reported in the regulation of pathways of hematopoiesis. In this setting, an ACE-regulated peptide network orchestrating hematopoiesis has emerged. Here, we focus on this peptide network and discuss the roles of ACE and its peptides in aspects of hematopoiesis. Special attention is given to the recent revelation that ACE is a bona fide marker of hematopoietic stem cells.