British Researchers Make Stem Cell Advance for Bone
Emma Ross,
Medical Writer

December 7, 2000; London, UK (AP) -- Researchers have made unspecialized embryo cells transform into bone for the first time, an advance that may offer hope for repairing diseased bones and correcting genetic bone disorders. Nearly 90 percent of the mouse embryonic stem cells evolved into bone nodules when allowed to grow in a lab dish for 21 days, Lee Buttery, a British scientist, told a symposium on stem cell research in London on Wednesday. Buttery's work is to be published in the January issue of the journal Tissue Engineering.

Embryonic stem cells, the predecessors of all tissue in the body, have become a hot area of medical research because scientists believe they may eventually be able to treat scores of diseases by renewing sick body parts with injections of replacement cells. "This could lead to the creation of purified bone cells to be used in bone repair without the problems of tissue rejection," said Buttery, a lecturer at London's Imperial College School of Medicine. "This would dramatically improve the methods of bone grafting and bone prosthesis in patients with severe traumatic bone injuries or suffering with diseases like osteoporosis." Embryonic stem cells have already been converted into nerve and muscle cells in previous research. Stem cells form when an embryo is four days old, and go on to make up every part of the body. Some types of stem cells are also found in adults. They do not appear to be as flexible as those blank cells found in embryos, but some studies suggest it might be possible to make them regress to a relatively unspecialized state and to redirect them into desired cell types.

Opponents of embryo research argue that scientists should focus on investigating the potential of adult stem cells. Brigid Hogan, a stem cell researcher from Vanderbilt University in Nashville, TN, said that while the British research adds bone to the list of cell types that have successfully been derived from embryo stem cells, using cells from adults might be a more simple and practical approach for bone disorders. She said scientists have demonstrated that skin taken from adults can be turned into bone and that most of the excitement over embryo stem cell research centers on the hope for producing transplantable cells that are desperately needed, such as brain cells for Parkinson's disease patients and insulin-producing pancreatic cells for diabetics.

In his study, Buttery removed stem cells from a mouse embryo and let them grow in a lab dish filled with a liquid specially concocted to provide the optimum environment for the evolution of bone cells. A steroid hormone was added to enhance the chances of the cells committing themselves to becoming bone. "Bits of fetal bone also were added to the mixture to release bone growth factors, which further helped persuade the stem cells to turn into bone," he said. "At the end of the experiment, the dish contained some nerve cells and muscle cells, but about 90 percent of the cells were bone, Buttery said. "Nobody knows for sure whether human embryonic stem cells will behave the same way," he said. "But by finding the conditions under which we can control the development of the mouse embryonic stem cells, you should be able to apply the general principles to humans."

The study results were released ahead of a scheduled parliamentary vote this month on whether to allow scientists in Britain to conduct research on human embryos, either donated or specially created, to develop cell-based therapies.