Where do stem cells come from?

Pluripotent stem cells are isolated from human embryos that are a few days old. Cells from these embryos can be used to create pluripotent stem cell "lines" —cell cultures that can be grown indefinitely in the laboratory. Pluripotent stem cell lines have also been developed from fetal tissue obtained from fetal tissue (older than 8 weeks of development). 

-Embryonic stem cells, as their name suggests, are derived from embryos. Specifically, embryonic stem cells are derived from embryos that develop from eggs that have been fertilized in vitro—in an in vitro fertilization clinic—and then donated for research purposes with informed consent of the donors. 

-An adult stem cell is a cell found in a tissue or organ, which can renew itself, and can differentiate to yield the major specialized cell types of the tissue or organ. The primary role of adult stem cells in a living organism is to maintain and repair the tissue in which they are found.

What are the unique properties of all stem cells?

Stem cells differ from other kinds of cells in the body. All stem cells—regardless of their source—have three general properties: they are capable of dividing and renewing themselves for long periods; they are unspecialized; and they can give rise to specialized cell types.

What is the US policy on stem cell research?

On August 9th, 2001, President George W. Bush announced that federal funds may be awarded for research using human embryonic stem cells if the following criteria are met:

·        The derivation process (which begins with the destruction of the embryo) was initiated prior to 9:00 P.M. EDT on August 9, 2001.

·        The stem cells must have been derived from an embryo that was created for reproductive purposes and was no longer needed.

·        Informed consent must have been obtained for the donation of the embryo and that donation must not have involved financial inducements. 

Note: However, in President Bush’s 2006 State of the Union Speech he stated, “Tonight I ask you to pass legislation to prohibit the most egregious abuses of medical research: human cloning in all its forms.” The US has, since that time, fallen behind the world community in the research of the uses of cell cloning and this statement has left little room for development of laws and limitations of the potential misuse of this research. The US currently has only as much regulatory oversight of this process as many third world countries.

Have human embryonic stem cells been used successfully to treat any human diseases yet?

Scientists have only been able to do limited experiments with human embryonic stem cells. Because many academic researchers rely on federal funds to support their laboratories, they are limited in their ability to learn how to grow and use the cells. Thus, although hESC are thought to offer potential cures and therapies for many devastating diseases, research using them is still in its early stages.

Adult stem cells such as blood-forming stem cells in bone marrow (called hematopoietic stem cells, or HSCs) are currently the only type of stem cell commonly used to treat human diseases. Doctors have been transferring HSCs in bone marrow transplants for over 40 years. More advanced techniques of collecting, or "harvesting", HSCs are now used in order to treat leukemia, lymphoma and several inherited blood disorders.

The clinical potential of adult stem cells has also been demonstrated in the treatment of other human diseases that include diabetes and advanced kidney cancer. However, these newer uses have involved studies with a very limited number of patients.

May individual states pass laws to permit human embryonic stem cell research?

Individual states have the authority to pass laws to permit human embryonic stem cell research using state funds. Unless Congress passes a law that bans it, states may pay for research using human embryonic stem cell lines that are not eligible for federal funding