Ethical and Plentiful Stem Cells From Milk

Embryonic-like stein cells have been discovered in breast milk in large numbers. This is the first time such cells have been found in an adult. If the cells live up to their potential we may soon have stem cells for medical therapy, without destroying any embryos.

Back in 2008, Peter Hartrnann at the University of Western Australia in Crawley and his colleagues announced they had discovered stem cells in breast milk. Crucially, these cells have now been turned into the kind that represent all three embryonic germ layers —the endoderm, mesoderm and  ectoderm — a defining property of embryonic stem cells (ESCs). "They can become bone cells, joint cells, pancreatic cells that produce their own insulin, liver cells that produce albumin, and neuronal cells," says Foteini Hassiotou of Hartmann's team, who led the recent work.

The cells also express the majority of protein markers that you would expect to find in ESCs. "What is really amazing is that these cells can be obtained in quite large amounts in breast milk," Hassiotou adds.

She says the stein cells make up around 2 per cent of cells in breast milk, although the number varies according to how long the woman has been producing milk and how full her breasts are. Hassiotou will present the work early next year at the 7th International Breastfeeding and Lactation Symposium in Vienna, Austria.

Many researchers remain sceptical. "Perhaps there are some mammary gland stem cells that can be coaxed to have a broader potential, but! very much doubt that embryonic-like cells normally exist in the breast," says Robin Lovell-Badge of the UK's National Institute for Medical Research in London.

The real test will be to inject these cells into mice and see if they form teratomas — tumours containing tissue or structures derived from all three germ layers. "That's the gold standard for whether you have a true pluripotent cell," says Chris Mason of University College London. Hassiotou says they will start these tests in coming weeks.

Embryonic-like stem cells have been found in amniotic fluid and the umbilical cord, but never before in adults. Other adult stem cells exist, such as those that can generate blood or turn into bone, fat and cartilage cells. But these stem cells cannot generate as many cell types as the breast milk cells appear to. "If they are truly embryonic, this would be another way of getting stem cells that would not raise ethical concerns," says Mason.

Even if they do not turn out to be ESCs, these breast milk cells could still have great potential for regenerative medicine. "It might be possible to grow these cells then bank them so that if or when t he mother develops some disease later in life, such as diabetes, her cells may be defrosted and differentiated into pancreatic beta cells," says Lyle Armstrong of Newcastle University, UK, although he cautions that more tests are needed to determine exactly what these cells are.

SOURCE : NEWS SCIENTIST MAGAZINE NOVEMBER 2011