WHAT ARE THE RELATIVE BENEFITS OF EMBRYONIC STEM CELLS VERSUS ADULT STEM CELLS?

Unlike adult, or tissue-specific, stem cells, embryonic stem cells can become any other cell in the body. They aren’t limited to one specific cell or type of tissue. Not only does this flexibility allows researchers to treat a multitude of different diseases with one type of cell, it also allows them to treat tissues where adult stem cells are rare, such as the brain and spinal cord. Embryonic stem cells also show nearly unlimited ability to self renew under the right conditions, whereas adult stem cells often have limited ability to create a large number of new cells. Researchers can potentially gain a near unlimited supply of stem cells from even the smallest sample of embryonic stem cells.

WHAT DOES POTENCY MEAN WHEN REFERRING TO STEM CELLS?

Stem cells are often defined by their potency, or how many different types of cells they can become. As stem cells specialize they can create fewer and fewer different types of cells. Pluripotent stem cells can become any of the 200 some cells in the human body. Multipotent cells can become many different cells but only of certain tissues. For example, stem cells of the bone marrow can make every type of blood cell. Unipotent cells can only become one type of new cell.

ARE THERE OTHER KINDS OF STEM CELLS?

A third type of stem cell, called an induced pluripotent stem cell (IPS cell), is created by taking a regular cell, often a skin cell, stem cell and “reprogramming” it to change into a stem cell very similar to that of an embryo. UC Irvine researchers are blazing new trails in the development of this type of stem cell. With IPS cells, researchers can get the benefits of embryonic stem cells, without requiring any embryos.

WHAT ARE STEM CELL LINES?

When researchers establish a group of stem cells in the lab that can self renew and grow new cells indefinitely, they call this group of cells a “line.” Creating these lines gives researchers a steady supply of stem cells to use in experiments and therapy. Each line is essentially immortal, allowing researchers to use the same stem cells for continued research without going through the arduous process of isolating new cells from human tissue.

HOW DO WE CREATE NEW STEM CELL LINES?

Embryonic stem cell lines are created by taking a 5-day old embryo, stripping its outer layer of protective cells, and then placing the remaining stem cells into a special culture. These embryos come from couples undergoing in-vitro fertilization who donate extra embryos to science. Cell lines created from adult stem cells are typically created by “reprogramming” adult cells to revert to a state similar to that of an embryonic stem cell.