Glossary Terms

Adult stem cells

An undifferentiated cell found in a differentiated tissue that can renew itself and differentiate (with certain limitations) to give rise to all the specialized cell types of the tissue from which it originated. These stem cells can give rise to specialized cell types of the tissue from which they came, i.e., a heart stem cell can give rise to a functional heart muscle cell, but it is still unclear whether they can give rise to all different cell types of the body.

Allogeneic transplantation

Cell, tissue or organ transplants from one member of a species to a genetically different member of the same species.

Autologous transplantation

Cell, tissue or organ transplants from one individual back to the same individual. Such transplants do not induce an immune response and are not rejected.

Bone Marrow

A spongy tissue inside large bones where the body's blood cells (red cells, white cells and platelets) are made.

Bone Marrow Transplant (BMT)

Giving healthy bone marrow to patients whose marrow is damaged. There are two types: allogeneic and autologous.

Dendritic cells

Immunocompetent cells of the lymphoid and Hematopoietic systems and skin. They are also called interdigitating, reticular, and veiled cells. They function morphologically and phenotypically by presenting or processing antigens, thereby stimulating cellular immunity.

Differentiation

The process of development with an increase in the level of organization or complexity of a cell or tissue, accompanied with a more specialized function.

Donor

A volunteer who has donated stem cells for a patient.

Embryo

In humans, the developing organism from the time of fertilization until the end of the eighth week of gestation, when it becomes known as a fetus.

Embryonic stem cell

Primitive undifferentiated cells derived from a 5-day preimplantation embryo that have the potential to become a wide variety of specialized cell types.

Engraftment

The stage when the stem cells given during the transplant start to grow and make the cell types in which they reside. For example, hematopoietic stem cells engraft when they become part of the bone marrow and begin to produce red and white blood cells and other stem cells. Mesenchymal stem cells engraft when they begin to product the tissue type in which they were transferred. For example, stem cells injected into the heart begin to product heart muscle and vascular cells, stem cells transplanted into the pancreas begin to product pancreatic cells that further produce islet cells and insulin.

Graft-versus-host disease (GVHD)

A condition that occurs following stem cell or other tissue transplantation in which the donor's immune cells, in the transplanted tissue, make antibodies against the host's tissues. GVHD can be chronic or acute. The acute phase can be so overwhelming as to be life threatening.

Hematopoietic stem cells

The precursors of mature blood cells that are defined by their ability to replace the bone marrow system following its obliteration (for example, by gamma-irradiation) and can continue to produce mature blood cells. Blood cells include red and white cells, platelets, dendritic cells etc.

Hematopoietic cell transplantation

The transplantation of hematopoietic stem cells with blood-forming potential. Hematopoietic stem cells provide rapid and sustained reconstitution of blood formation and are found in adult bone marrow, umbilical cord blood, peripheral blood and in fetal liver tissue.

Immunology

The study of all aspects of the immune system including its structure and function, disorders of the immune system, blood banking, immunization and organ transplantation.

Immunosuppressant

An agent that can suppress or prevent the immune response. Immunosuppressants are used to prevent rejection of a transplanted organ, tissue or cells and to treat autoimmune diseases such as psoriasis, rheumatoid arthritis, and Crohn's disease.

In vitro

From the Latin for, "in glass"; in a laboratory dish or test tube; an artificial environment.

In vitro fertilization (IVF)

Mesenchymal stem cell

Also known as bone marrow stromal cells, mesenchymal stem cells are rare cells, mainly found in the bone marrow and fat tissue. They can give rise to a large number of tissue types such as bone, cartilage (the lining of joints), fat tissue, and connective tissue (tissue that is in between organs and structures in the body).

Oxidative damage

Damage cause by oxidative stress including free radicals, toxins, etc.

Pathogen

An agent of disease. A disease producer. The term pathogen most commonly is used to refer to infectious organisms.

Peripheral Blood

Peripheral blood flows through the bloodstream in the body. Some blood stem cells are found in the peripheral blood.

Regenerative medicine

Medical interventions that aim to repair damaged organs, most often by using stem cells to replace cells and tissues damaged by aging and/or disease. A non-blood cell that is derived from blood organs, such as bone marrow or fetal liver, which is capable of supporting growth of blood cells in vitro. Stromal cells that make up the matrix within the bone marrow are derived from the mesenchyme and give rise to fat and cartilage.

Stem Cell

A cell that has the ability to divide for indefinite periods in culture and to give rise to specialized cells.

Stromal cell

A non-blood cell that is derived from blood organs, such as bone marrow or fetal liver, which is capable of supporting growth of blood cells in vitro. Stromal cells that make up the matrix within the bone marrow are derived from the mesenchyme and give rise to fat and cartilage.

Totipotent

A totipotent stem cell can give rise to all the cell types that make up the body plus all of the cell types that make up the extra embryonic tissues such as the placenta.

Umbilical cord blood stem cells

Hematopoietic stem cells are present in the blood of the umbilical cord during and shortly after delivery. These stem cells are in the blood at the time of delivery, because they move from the liver, where blood-formation takes place during fetal life, to the bone marrow, where blood is made after birth. Umbilical cord stem cells are similar to stem cells that reside in bone marrow, and can be used for the treatment of leukemia, and other diseases of the blood.