Stem Cells in The Spotlight

What is a Stem Cell?

A stem cell is a cell whose job in the body is yet not determined.Every single cell of the body 'stems' from this cell, hence the name. Stem cells have a lot of potential,they can become any kind of cells.But, until it receive a signal,it has to wait patiently and divide slowly.

When a stem cell receives a signal,it begins to differentiate or change into it's destined cell type.

The signals tell him to turn on certain genes and make new proteins.These new proteins help him to look and act like the cells he is supposed to become.By the time he finishes diferentiating,he would have stopped dividing too.

Did you know that several stem cell therapies are routinely used to treat disease today?

These include:

* Adult Stem Cell Transplant: Bone Marrow Stem Cells
* Adult Stem Cell Transplant: Peripheral Blood Stem Cells
* Umbilical Cord Blood Stem Cell Transplant

Adult Stem Cell Transplant: Bone Marrow Stem Cells

Perhaps the best-known stem cell therapy to date is the bone marrow transplant, which is used to treat leukemia and other types of cancer, as well as various blood disorders.

Why is this a stem cell therapy?

Leukemia is a cancer of white blood cells, or leukocytes. Like other blood cells, leukocytes are made in the bone marrow through a process that begins with multipotent adult stem cells. Mature leukocytes are released into the bloodstream, where they work to fight off infections in our bodies.

Leukemia results when leukocytes begin to grow and function abnormally, becoming cancerous. These abnormal cells cannot fight off infection, and they interfere with the functions of other organs.

Successful treatment for leukemia depends on getting rid of all the abnormal leukocytes in the patient, allowing healthy ones to grow in their place. One way to do this is through chemotherapy, which uses potent drugs to target and kill the abnormal cells. When chemotherapy alone can't eliminate them all, physicians sometimes turn to bone marrow transplants.

In a bone marrow transplant, the patient's bone marrow stem cells are replaced with those from a healthy, matching donor. To do this, all of the patient's existing bone marrow and abnormal leukocytes are first killed using a combination of chemotherapy and radiation. Next, a sample of donor bone marrow containing healthy stem cells is introduced into the patient's bloodstream.
If the transplant is successful, the stem cells will migrate into the patient's bone marrow and begin producing new, healthy leukocytes to replace the abnormal cells.

Adult Stem Cell Transplant: Peripheral Blood Stem Cell Transplant

While most blood stem cells reside in the bone marrow, a small number are present in the bloodstream. These multipotent peripheral blood stem cells, or PBSCs, can be used just like bone marrow stem cells to treat leukemia, other cancers and various blood disorders. Since they can be obtained from drawn blood, PBSCs are easier to collect than bone marrow stem cells, which must be extracted from within bones. This makes PBSCs a less invasive treatment option than bone marrow stem cells. PBSCs are sparse in the bloodstream, however, so collecting enough to perform a transplant can pose a challenge.

Umbilical Cord Blood Stem Cell Transplant

Newborn infants no longer need their umbilical cords, so they have traditionally been discarded as a by-product of the birth process. In recent years, however, the multipotent-stem-cell-rich blood found in the umbilical cord has proven useful in treating the same types of health problems as those treated using bone marrow stem cells and PBSCs.
Umbilical cord blood stem cell transplants are less prone to rejection than either bone marrow or peripheral blood stem cells. This is probably because the cells have not yet developed the features that can be recognized and attacked by the recipient's immune system. Also, because umbilical cord blood lacks well-developed immune cells, there is less chance that the transplanted cells will attack the recipient's body, a problem called graft versus host disease.

Both the versatility and availability of umbilical cord blood stem cells makes them a potent resource for transplant therapies.

What is the Goal of Stem Cell Research?

Why don't we live forever?

Because we get sick?

Because we get old?

Because we get hurt and can't heal?

All of these are correct. Each one results from a failure of the body's ability to grow, maintain or repair itself - functions that depend on our stem cells.We know how stem cells form the basic building materials for the human body. This makes them good candidates for restoring tissues that have been damaged by injury or disease.
For decades, researchers have been studying the biology of stem cells to figure out how development works and to find new ways of treating health problems.

How would stem cell therapy work?

The goal of any stem cell therapy is to repair a damaged tissue that can't heal itself.
This might be accomplished by transplanting stem cells into the damaged area and directing them to grow new, healthy tissue.
It may also be possible to coax stem cells already in the body to work overtime and produce new tissue.
To date, researchers have found more success with the first method, stem cell transplants.

Ref : Learn.Genetics at the Utah University