Stem cells 101

My heart goes out to patients and families waiting for effective treatments and cures.

I, too, have been waiting, and actively working toward a cure for my paralysis since a 1980 spinal cord injury.

A bill making its way through the Legislature, the Human Cloning Prohibition Act, has created quite a stir among those who say its passage would hinder research and treatment.

I respectfully disagree. As someone who stands to benefit from cutting-edge research, I'd like to clear up some common misunderstandings.

This short Q&A will help you understand human cloning and stem cell research so that you can accurately voice your opinion.

What are stem cells?

Stem cells are essentially "blank" cells found in embryos and humans of any age that can divide and change into specialized cells (such as heart or nerve cells). It is important to distinguish between embryonic stems cells and adult stem cells.

Harvested from five-day-old embryos, they are cells that normally would develop into a fetus and then a baby. All current embryonic stem cells are from fertilized embryos acquired from fertilization clinics.

What are adult stem cells?

Obtained from many tissues in humans throughout their lifespan, these cells generate replacements for old or damaged cells. For example, bone marrow stem cells replenish blood cells, but can also stimulate repair of other tissues.

Do embryonic stem cells present any medical problems?

Yes. Designed for rapidly growing embryos, they are unpredictable when implanted in adults and often form tumors called teratomas (made up of hair, teeth, and bone, for example). Because of genetic differences, embryonic stem cells also cause tissue rejection. To date, no human being has been successfully treated using embryonic stem cells.

No. Adult stem cells do not cause tissue rejection or form tumors, and they are already being used for over 73 human treatments (see www.stemcellresearch.org ). Examples of successful treatments (not all necessarily cures) include heart damage, spinal cord injury, multiple sclerosis, corneal blindness and sickle cell anemia.

What is human cloning?

Simplified, the DNA from a patient's somatic (body) cell is inserted into a woman's egg, from which the DNA has been removed. The resulting embryo (clone) would supposedly be genetically identical to the patient.

What is the difference between "therapeutic cloning" and "reproductive cloning"?

The cloning process is the same, but in "reproductive cloning" the embryo would be implanted in a womb to develop into a child, while in "therapeutic cloning" the stem cells would be extracted from the embryo for research. No human clones have yet been brought to birth, and no human embryonic stem cells have ever been isolated from cloned embryos.

Yes. Cloning results in abnormal genetic expression. (Dolly, the cloned sheep, had many medical issues because of this problem.) And cloned stem cells, like any other embryonic stem cells, can form tumors. Also, the large number of human eggs needed for human cloning would exploit women by subjecting egg donors to health risks. For example, it is estimated that more than 100 eggs would be needed to get one dish of cells for each patient. That means that for the 18 million U.S. diabetics, over 1.8 billion human eggs would be needed.

What does this bill do?

The Human Cloning Prohibition Act would prohibit the creation of cloned human embryos for any purpose, and prohibits shipping or receiving any product from such an embryo. It would not affect any current stem cell research, including all current human embryonic stem cell research.

Actually, this bill does not hinder any effective cure research and treatment. Supporters of embryonic stem cell research and cloning often use words like "hope" and "potential" because they know that safe and effective cures are years, possibly decades, away. On the other hand, successful therapies using adult stem cells have already been used in humans for years, and more treatments are continually being developed.

Passing the Human Cloning Prohibition Act will help ensure that limited public resources will not be used for futile, ineffective research purposes, but rather for those that are most beneficial to real people with real medical issues.