Scientists from US claim to have isolated parent cells from the bone marrow, which can give rise to various tissues like bone, cartilage, fat and muscle.Embryonic stem cells are "totipotent;" meaning they can differentiate into various cell types
Mark Pittenger and colleagues from Osiris Therapeutics report in the journal Science that they have isolated stem cells that are multipotent; that is, the cells are capable of differentiating into a more limited number of specialised roles - in this case, mesenchymal tissues.
Researchers had previously managed to isolate from human bone marrow a different type of stem cell, one that renews circulating blood elements such as red and white blood cells.
A combination of stem cell and cloning techniques may make it possible to grow from scratch human tissues for use in transplants.
At a cloning conference in London this week, a leading UK embryologist predicted the technologies would enable scientists to grow life-saving bone marrow in the lab for children with leukaemia. It would involve extracting the nucleus of a cell taken from a child, and transferring it to an unfertilised egg which had had its own nucleus removed.
The egg, programmed by the child's DNA inside the nucleus, would then start to divide and form an embryo. At an early stage, the embryo would be dismantled to obtain stem cells. These would then be treated with the right chemical growth factors to trigger their development into bone marrow cells.