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发布时间:2019-03-07 04:19:02来源:未知点击:

By Andy Coghlan and Emma Young Mature skin cells have been transformed into stem cells and then into beating heart cells , US scientists claim. This is the first time a fully differentiated adult cell has been reprogrammed. The breakthrough gives scientists a way to produce multipotent stem cells for treating conditions such as heart disease or diabetes without creating an embryo clone of the patient. Therapeutic cloning has been attacked by anti-abortion campaigners. Researchers at PPL Therapeutics in Blacksburg, Virginia say they took adult skin cells from cattle, ‘reverted’ them into stem cells and then transformed them into heart cells. “We were very pleased, because we didn’t expect it,” says Alan Coleman, director of research at PPL in the UK. Previously scientists have isolated stem cells from embryos and coaxed them into specific tissues. They have also taken partly developed cells from one tissue and converted them into different tissue. “The major message from cloning was that an adult cell with a specialised life could be reprogrammed – its disk wiped clean. That was done by first making an embryo. We’re en route to doing that without going through the embryo stage,” says Coleman. For commercial reasons, Coleman refuses to reveal exactly how the procedure was performed. “The holy grail is to reprogram a cell by putting it in chemicals, but we can’t say if that’s what we’ve done now,” he says. Experiments in 1997 by Azim Surani of the Institute of Cancer Research in Cambridge, UK suggested that an adult mouse cell could be reprogrammed by fusing it with a clump of embryonic mouse stem cells stripped of their nuclear DNA (New Scientist, 29 January 2000). So a clump of cultured cells could serve as a standardised “capsule” for reprogramming a patient’s own cells. “One of the ideas is to take part of an embryonic stem cell then use the cytoplasm to reprogram the nucleus of a cell,” says Coleman. “I can’t confirm or deny if that is what we’ve done here.” The team now hopes to demonstrate that adult cells can be transformed into a wide range of cells. “Our main aim is to solve diabetes by creating insulin producing cells we can implant in patients,” Coleman says. The major challenge is to repeat the procedure with human cells. This work will probably take place in the UK, says Coleman. See also: New Scientist,