Haematopoietic Stem Cells

The production of blood cells, or hematopoiesis, takes place in the bone marrow. Among the billions of cells in the bone marrow, there is a very small subpopulation that has a pivotal role in the maintenance of hematopoiesis. This subpopulation is composed of hematopoietic stem cells (HSC) that, with their distinctive capabilities of self-renewal and differentiation, furnish a constant supply of blood cells of all hematopoietic lineages throughout life. Thus, the stem cell can either replicate and remain a stem cell or differentiate into myeloid or lymphoid stem cells, which in turn can further proliferate and mature, ultimately giving rise to all the circulating blood cells.

Currently, allogeneic bone marrow transplants are recognized as a treatment of choice for chronic myelogenous leukemia, acute leukemias failing initial treatment, aplastic anemia, and several lethal disorders of the immune system and of hematopoiesis. Allogeneic bone marrow transplantation has become increasingly used as a cure for a variety of genetic defects of the hematopoietic and immune systems, and for lipid storage diseases. Genetic diseases that have been successfully cured by bone marrow transplantation include Cooley's anemia, sickle cell anemia, severe combined immunodeficiency, Wiskott-Aldrich syndrome, Fanconi anemia, Blackfan-Diamond anemia, ataxia telangiectasia, infantile agranulocytosis, Chediak-Higashi disease, chronic mucocutaneous candidiasis, mucopolysaccharidosis, cartilage-hair hypoplasia, Gaucher's and other lipid storage diseases. Some of these diseases, such as Cooley's anemia (beta-thalassemia) and sickle cell anemia, are major worldwide public health problems. Others are devastating orphan diseases that are extremely costly to treat. Collectively, these genetic diseases occur in tens-of-thousands of births per year.

It is also recognized that several malignant disorders are sensitive to agents which have, as their dose-limiting toxicity, myelo-ablation. This knowledge, along with the initial success of marrow and peripheral blood-derived autografts administered after myelo-ablative therapy, have clearly defined the rationale for the use of hematopoietic stem and progenitor cells in the treatment of several non-hematopoietic malignancies, including breast cancer, which occurs with alarming frequency.

Stem cell transplantation (SCT) has achieved significant therapeutic success over the last 10 years, providing a viable treatment option for many previously incurable diseases. However, several inherent limitations of the procedure have restricted its widespread use. These include: lack of sufficient donors for all recipients, a period of bone marrow (BM) aplasia leading to severe, prolonged neutropenia and thrombocytopenia, and the potential for tumor contamination in autologous SCT. Continued research efforts to address these limitation are needed. Recent studies suggest that cord blood transplantation may help eliminate the issue of donor availability and some post-transplant complications.

The following articles are sure to give you a detailed understanding of Haematopoietic Stem Cells and the clinic applications:

Pluripotent Hemopoietic Stem Cells in Mice and Humans

Biology of Human Umbilical Cord Blood-Derived Hematopoietic Stem/Progenitor Cells

The Role of Blood Stem Cells in Hematopoietic Cell Renewal

The Biology and Clinical Uses of Blood Stem Cells

Qualitative and quantitative aspects of haematopoietic cell development in the mammalian embryo

Developmental changes in the differentiation capacity of haematopoietic stem cells

Hematopoietic stem cells: Are they CD34-positive or CD34-negative?