 |
 |
Adult stem cell obstacles stress need for SCNT - by Steven Teitelbaum, MD November 24, 2006 Editor's Note: Dr. Teitelbaum, a world renowned medical scientist from the Washington University School of Medicine in St. Louis, is an avid proponent of the advancement of new stem cell technologies. His own experiences as a researcher using adult stem cells places him in the unique position of providing an accurate perspective of the relationship between embryonic and adult stem cell research, noting it is not a contest, but a collaboration. Teitelbaum was part of a team of three scientists who debunked the false claim by David Prentice that adult stem cells were being used to treat 65 different diseases. While it is most unusual for the Stem Cell Page to reprint a year-old Congressional transcript as an editorial, Dr. Teitelbaum agreed that in this case it is completely appropriate. - Jeff Eisen Testimony of Dr. Steven Teitelbaum before the Subcommittee on Labor, Health and Human Services October 19, 2005 Thank you Mr. Chairman, My name is Steven Teitelbaum. I'm the Wilma and Roswell Messing Professor of Pathology and Immunology at Washington University School of Medicine and I thank the committee for the honor of speaking to you today. Mr. Chairman, I've been a physician-scientist for more than 30 years. I've authored in excess of 300 scientific papers and I'm here to tell you that, in my estimation, we are facing a unique opportunity in the form of embryonic stem cell research, to potentially alleviate the misery of our fellow Americans with a number of presently incurable diseases. But to get there, we must do the science. Opponents of human embryonic stem cell research often articulate their position as a contest between adult an embryonic stem cells. Mr. Chairman, this is not a contest between various types of stem cells. It is a contest between us as a society and disease. We should be moving forward on all fronts, adult, embryonic and umbilical cord stem cells, to win the battle. The tool is not important. What counts is curing our neighbors. That said, because of their flexibility, embryonic stem cells hold more promise to ameliorate presently incurable diseases than any other approach. I stress the word "promise" because we are not there yet and it is my belief that it will be some time before we are positioned to safely use these cells for therapy. But if scientists are prevented from exploring the biology of human embryonic stem cells, we will never get there. Mr. Chairman, as you know, human embryonic stem cells can presently be obtained from two sources, namely the spare products of in vitro fertilization, which ultimately would be destroyed, and by somatic cell nuclear transfer, also known as SCNT or therapeutic cloning. Although both approaches hold enormous therapeutic potential, I'm particularly taken with the promise of SCNT because it may alleviate the major complication of tissue and cell transplantation, namely rejection and its attendant life threatening consequences. Mr. Chairman, I'm a bone biologist and physician and as such I see many patients who have received organ and cell transplants. These patients typically develop severe osteoporosis and often have many fractures because of the harsh medications they must take to prevent rejection of their transplant. It is my hope that embryonic stem cells, generated by SCNT, which contain the transplant recipient's own DNA, will reduce the necessity for these devastating anti-rejection drugs. But Mr. Chairman, my hopes for SCNT are more personal and hearken back more than 20 years when I was a young assistant professor. At that time I became interested in a genetic disease of the skeleton known as osteopetrosis or marble bone disease and I want to tell you a story about an afflicted child who profoundly impacted my life. Osteopetrosis is a disease in which kids make too much bone. Consequently, their skulls become very thick and compress their brains and nerves, such as those leading to the eye. Bone also overgrows the bone marrow preventing formation of blood cells. Until the story I'm about to tell you, all kids with the malignant form of osteopetrosis developed fatal neurological complications, including blindness, and infections due to bone marrow suppression. These children invariably died in the first decade, most before the age of five. In the early 80s, our team thought we had identified the abnormal cell causing osteopetrosis and concluded it resided in the bone marrow. We reasoned, therefore, that if we gave an osteopetrotic infant a bone marrow transplant, which contains adult stem cells, we might cure the disease. We realized the enormous risk of rejection so we waited until we had a perfect immunological match between the donor and recipient, in this case a 3 month old little girl you see in the top picture. So we gave this baby a bone marrow transplant and achieved the first cure of this disease. The middle panel shows her at 3 years of age and the bottom picture, which is recent, was taken upon her graduation from college. Senators, being part of a team which is first to cure a fatal disease, particularly of children, is a doctor's dream. It doesn't get any better. You may be asking yourselves why this guy, who is here as an advocate of embryonic stem cell research, is telling us about his victory with adult stem cells. Senators, I'm recounting the story to underscore the importance of moving forward on all fronts because regrettably there is a downside to my tale. You'll remember that this was a perfect immunological match and therefore there was little chance of rejection. Unfortunately, such matches are extremely rare and therefore we presently cure less than 10% of kids with osteopetrosis. The use of SCNT, in which embryonic stem cells contain the patient's own DNA, if successful, would markedly increase the cure rate of this disease. Mr. Chairman, because of my familiarity with osteopetrosis I'm frequently contacted by parents with afflicted children. I have to tell them the chances of curing your child is no more than 10%. I want to tell them it's greater than 90%. SCNT, if we pursue it, may get us there. ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn