What Are Stem Cells?

So What Exactly are Stem Cells?

Stem Cells are primitive cells that can differentiate into mature cells or self-renew to create more stem cells. They are multipotent, which means they can develop into multiple types of mature cells.

There are Two Types of Stem Cells

Embryonic Stem Cells are derived from early-stage embryos before mature organs and tissues have developed. Embryonic stem cells have the greatest potential for both self-renewal (creating large numbers of stem cells) and differentiation into many different types of mature cells (bone, muscle, blood, brain, etc.)

Adult Stem Cells are derived from adult human donors. These cells still self-renew to create more stem cells, but their multipotency – ability to develop into multiple types of cells – is limited to mature cells of a certain type, such as the cells of the brain, blood, bone, or muscle.

Cellerant's products are all based on Adult Stem Cells.

What are Hematopoietic Stem Cells?

The most widely known adult stem cell is the adult Hematopoietic (blood-forming) Stem Cells (HSC). HSCs are adult stem cells that produce cells in the blood and immune system. HSCs create red blood cells, platelets, neutrophils, dendritic cells, T cells, B cells, and NK cells. HSCs are the "active ingredient" in a bone marrow transplant, and normally reside in the bone marrow. The HSCs in your body create blood and immune cells throughout your life.

What are Progenitor Cells?

Progenitors Cells are primitive like stem cells, but they are more limited in the different types of cells they can create, and they lack the stem cell's ability to create more of themselves. For example, in the blood forming system, the Myeloid Progenitor Cell can create myeloid cells (such as red blood cells and neutrophils) but not lymphoid cells (like T-cells and B-cells).

What is a Stem Cell Transplant?

The term Stem Cell Transplant most often refers to the transplant of hematopoietic (blood-forming) stem cells, also called bone marrow transplants.

Stem cell transplants involve a donor (who supplies the stem cells) and a patient (who receives the stem cells). In an autologous (patient-to-patient) transplant, the donor and the patient are the same: patients donate to themselves before undergoing a treatment, usually for cancer, which is likely to kill their bone marrow stem cells. In an allogeneic (donor-to-patient) transplant, the donor is someone whose stem cells are a compatible with the patient: a closely matched relative or someone from a marrow donor registry.

Most stem cell transplants today are performed with Mobilized Peripheral Blood. In this procedure, a drug is given to “mobilize” the HSCs from the donor's bone marrow. The donor is then connected to an apheresis machine. The apheresis machine collects cells of a certain density, and, in this case, is tuned to collect cells with the density of stem cells. The donor's blood flows into the machine, stem cells and other cells are collected, and the remaining blood is returned to the donor. The donor graft material will be highly concentrated for stem cells compared to what was flowing through the donor's blood, but it is still only about 1% stem cells.

At the transplant center, the patient is given some combination of chemotherapy and radiation to kill their own bone marrow. The donor graft material, which contains stem cells and other cells, is then infused into the patient. The stem cells in the graft material find their way to the bone marrow and engraft. They start the process of engraftment by creating more of themselves to fill the bone marrow with stem cells. They then create progenitor cells, which in turn create the mature cells of the blood and immune system. This process can take up to 30 days, during which the patient receives supportive care and protection from infection while their new blood forming system gets up and running.