Collection and Processing of Stem Cells

[Guest guest]

Overview

" Following the delivery of high-dose chemotherapy to patients for the treatment

of cancer, infusion of stem cells is necessary to ensure recovery of bone marrow

function and production of red blood cells, white blood cells, and platelets.

Historically, stem cells were harvested from bone marrow, but more recently,

many cancer centers have adopted the practice of collecting stem cells from

peripheral blood.

" The collection of stem cells from bone marrow has been safely performed for

over 30 years. A bone marrow harvest is relatively simple and typically occurs

in the operating room. During a bone marrow harvest, patients receive general

anesthesia and then a surgeon inserts a large needle directly into the bone

marrow cavity of bones of the lower back after the area has been sterilized.

Bone marrow is aspirated or sucked out of the bones by inserting the needle into

the bone multiple times. A typical bone marrow harvest takes about two hours and

involves the removal of one liter of bone marrow containing the stem cells. The

major side effect of this procedure is discomfort at the site of the bone marrow

harvest. Infrequent complications include bleeding, infection, and nerve damage.

Peripheral Blood Stem Cell Harvesting

" The collection of stem cells from the blood is slightly more complicated than

collection from bone marrow and has been performed safely for over a decade.

Collecting stem cells from the peripheral blood may also have several clinical

advantages compared to collecting them from bone marrow.

Stem cells normally circulate in the blood in very small quantities and can be

collected from the blood through a small catheter inserted into a patient’s

vein. The number of circulating stem cells in the blood is increased in patients

whose bone marrow is recovering from chemotherapy. Cytokines (blood cell growth

factors) administered to patients after myelosuppressive chemotherapy can also

cause a 100-fold increase in the number of stem cells circulating in the blood.

Injection of cytokines stimulates increased production of immature and mature

bone marrow stem cells and their release into the blood, where they can be

collected. Cytokines can also be administered without chemotherapy and cause a

substantial increase in the number of circulating blood stem cells for

collection. The process of delivering a cytokine or growth factor with or

without myelosuppressive chemotherapy for the purpose of collecting stem cells

is referred to as " stem cell mobilization " . Two cytokines, Neupogen® and

Leukine™, stimulate the bone marrow's production of stem cells and are approved

by the Food and Drug Administration. These drugs are used in patients to

increase the number of circulating stem cells and several others are in

development.

" During stem cell mobilization, patients receive an injection of a cytokine and

are evaluated daily. The process of actually collecting the stem cells from the

blood is called apheresis and this begins when there are sufficient stem cells

circulating in the blood for collection. Stem cells are collected from the blood

flowing through a catheter inserted into a vein. Blood flows from thr vein

through the catheter into the apheresis machine, which separates the stem cells

from the rest of the blood and then returns the blood to the patient's body.

Apheresis is performed for several days until enough stem cells have been

collected to support treatment with high-dose chemotherapy. Most donors have

sufficient stem cells collected with 2-4 days of apheresis. "

Entire article can be viewed at this site:

http://www.caring4cancer.com/go/cancer/treatment/stemcell/collection-and-process\

ing-of-stem-cells.htm

FYI,

Lottie