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The source of this article is the Miami Herald: http://tinyurl.com/3kusr Stem-cell treatment of disease takes 2 leaps forward Two embryonic stem-cell research experiments showed great potential, taking a giant step toward the treatment of human heart and eye diseases. By RICK WEISS Washington Post Service The prospect of using human embryonic stem cells to treat disease appears a small step closer as the result of two new experiments with the cells, which are mired in controversy because they are derived from human embryos. In one report released Sunday, researchers showed that the versatile cells can serve as ''biological pacemakers,'' correcting faulty heart rhythms when injected into the failing hearts of pigs. In another report, scientists demonstrated for the first time that stem cells can become a cell crucial to vision. Many doctors believe that several vision-destroying diseases could be fought by transplanting these cells into the eyes. Human embryonic stem cells, derived from five-day-old embryos, have the biological potential to morph into virtually all of the 200 or so kinds of cells in the body. Researchers are racing to learn how to direct them to develop into specific types of cells that can be transplanted into failing organs. Izhak Kehat and Lior Gepstein of the Technion-Israel Institute of Technology in Haifa and their colleagues sought to test the capability of stem cells to grow into heart muscle cells. The team started with masses of stem cells growing in laboratory dishes, from which they isolated those few that were spontaneously developing into heart cells. They were easy to spot: They were the ones pulsing in unison, as heart cells do. The team threaded a probe into the hearts of 13 pigs and made a small burn in the area that regulates heartbeat, causing a permanent severe slowing of those animals' heart rates. The injury mimicked a human heart rhythm disorder that could be caused by disease or a small heart attack. Then they injected about 100,000 of their human embryo-derived heart cells into the pig hearts. Eleven of the 13 returned to faster heart rates, the team reported in Sunday's advanced online edition of Nature Biotechnology. A second report -- appearing in the fall issue of the journal Cloning and Stem Cells -- describes the first documented growth of retinal pigment epithelial (RPE) cells from human embryonic stem cells. RPE cells scavenge the retinal area for cellular debris, sucking old material up like little vacuum cleaners. They secrete substances that aid in tissue repair within the eye. The loss of RPE cells in middle and old age is a major cause of age-related vision loss, including macular degeneration. That disease is the leading cause of blindness in people older than 60. In experiments led by Irina Klimanskaya and Robert Lanza of Advanced Cell Technology in Worcester, Mass., human embryonic stem cells grown in lab dishes under certain conditions spontaneously became RPE cells. Lanza said the company hopes to complete transplant studies in large animals during the next year. ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn