New human embryo stem cell study

A new study published in the latest issue of the Proceedings of the National Academy of Sciences examines how cells in the early human embryo grow and develop into a range of different body tissues. The researchers say their work demonstrates the potential for using embryo stem cells to grow tissues to treat diseases, but stress it only represents an initial step forward.

The scientists, based at the Howard Hughes Medical Institute, Harvard and the Hebrew University, Jerusalem, applied eight different human growth factors (proteins that control cell growth and development) to human embryo cells growing in the laboratory. They found that each growth factor had a slightly different effect, directing the stem cells to grow into three types of tissue: endoderm, ectoderm and mesoderm. In the human embryo the endoderm eventually forms the gut, stomach and lungs; the ectoderm grows into skin, brain and nerves; and the mesoderm forms muscle, blood vessels, bones and many of the organs.

Douglas Melton, head of the Howard Hughes team, said that controlling embryo stem cell development will probably require the use of multiple growth factors used in a certain order and at certain times. 'It may be a bit like educating a child, in which you don't designate children in kindergarten as doctors, lawyers or surgeons, but you give them some kind of general education. And, as they progress and show an interest in a specific field, you give them a more specialised education' he added.

Meanwhile, US Senator Arlen Specter's long-awaited bill that proposes lifting the ban on federally-funded research into human embryo cells, due to be debated on 28 September, has been abruptly derailed by Senator Sam Brownback, reports last week's issue of Science.