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Therapeutic cloning of cells, tissue touted as a disease fighter Thursday, March 29, 2001 By Anita Srikameswaran, Post-Gazette Staff Writer While scientists and politicians in Washington, D.C., debated human cloning as a solution for infertility, tissue engineering experts in Pittsburgh yesterday talked about using cloning techniques to generate human replacement cells and tissues. This so-called therapeutic cloning could lead to revolutionary treatments for Type I diabetes, Parkinson's disease and other conditions. Dr. Robert Lanza, vice president of medical and scientific development at Massachusetts-based Advanced Cell Technology, talked about the technique at the Engineering Tissue Growth International Conference and Exposition, now under way at the Marriott City Center. "Cloning is conceptually very simple," Lanza said. A single mature cell from the skin is placed next to an egg from which the genetic material has been removed. A jolt of electricity is applied to the two cells, fusing them together and loading the skin cell's genetic material into the egg. "Then you fool the egg, chemically or otherwise, into thinking it's been activated and [so it] starts to divide," Lanza explained. A ball of about 100 cells, called a blastocyst, forms as new cells are generated. Rather than implanting the cell ball into the uterus of a surrogate mother, where it might then develop into a fetus, the primitive stem cells are put in test tubes and Petri dishes. There they can be treated with chemical growth factors and other agents. "The goal then would be to generate different replacement cell types in the laboratory and put them back in the patient" for disease treatment, Lanza said. So a patient with diabetes could get a transplant of insulin-making pancreatic cells that are genetically identical to his own. There would be no danger of rejection, and no long wait for a donor pancreas transplant. Similarly, neurons that make dopamine could be given to people with Parkinson's disease, who suffer from a progressive loss of the brain chemical. Lanza said cloning could also provide a means to avoid the biggest obstacle to transplanting animal organs into humans, also known as xenotransplantation. A type of sugar molecule is attached to the surface of blood vessel cells in animals. The human immune system recognizes the sugar as foreign and launches an all-out attack, which leads to rapid rejection of the animal organ. But scientists could snip out the gene that makes the offending sugar in an animal cell and clone it to produce mature animals with organs that will not set off the human immune system. Those organs could be used for transplantation. Lanza acknowledged that there are ethical issues at stake in human cloning. He said few scientists, including himself, would support it as a means to create new people. But the procedure holds the promise of alleviating many common diseases. Does the microscopic ball of cells used in the therapeutic cloning technique merit the same "rights and reverence" as a deathly sick child or adult? At the blastocyst stage of development, 90 percent of the cells are used to make the placenta and other non-embryonic tissues. "So they'd be discarded in any case," Lanza said. "Medically speaking, the first trace of the embryo doesn't occur until implantation" in the uterus. In January, the British House of Lords voted in favor of allowing this type of limited human cloning for medical research. "We would all like to be able to use the human [cell] lines," said K. Sue O'Shea, a developmental biologist at the University of Michigan. Apart from tissue engineering and other applications, there is a lot of basic science to be learned. "I've reviewed a lot of grant proposals and papers from people all over the world and we're not allowed to do the same research that I'm reviewing," O'Shea noted. "That's really frustrating." More than 550 people from 24 countries are attending the tissue engineering conference. http://www.post-gazette.com/healthscience/20010329cellclone4.asp ********** ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn