Possible stem cell breakthrough

Scientists reported in this week's Nature journal that they had found a way to reprogram mature mouse cells into an embryonic-like state that allows them to generate many types of tissue. The research suggests that scientists could in the future similarly reprogram human cells, offering a simpler way to replace damaged cells or grow new organs for sick and injured people. The experiments, reported in two papers in the journal Nature on Wednesday, involved scientists from the RIKEN Center for Developmental Biology in Japan and Brigham and Women's Hospital and Harvard Medical School in the United States.

"It's very simple to do," said Dr. Charles Vacanti of Brigham and Women's Hospital in Boston. "I think you could do this actually in a college lab."

Vacanti acknowledged that the technique could conceivably provide a new potential route towards cloning people - a subject that remains highly controversial. He has no interest in doing that, he said, but "it is a concern."

'A wide range'

Researchers wrote that they allowed mature adult cells from the mice to multiply and then subjected them to stress "almost to the point of death" by exposing them to various events, including trauma, low oxygen levels and acidic environments. Within days, the scientists found that the cells had survived and recovered from the stressful stimulus by naturally reverting to a state similar to that of embryonic stem cells. The cells created by exposure to stresses - dubbed STAP cells by the researchers - then differentiated and matured into different types of cells and tissue depending on their environments.

Haruko Obokata, a scientist at the RIKEN Center for Developmental Biology in Kobe, Japan, and one of the study's co-authors, said that researchers had begun studying whether the technique might work with humans. By making stem cells from the patients themselves, doctors could get around the problem of transplant rejection.

"If we can work out the mechanisms by which differentiation states are maintained and lost, it could open up a wide range of possibilities for new research and applications using living cells," said Obokata, who led the work at RIKEN.

Many possible uses

Stem cells, the body's master cells, can develop into all other types of bodily cells. Scientists believe that, by helping to regenerate tissue, they could offer ways of tackling diseases for which only limited treatments currently exist - such as strokes, heart disease and Parkinson's. Two primary types of stem cells exist: those harvested from embryos and adult or iPS cells, which scientists take from skin or blood and then reprogram back into stem cells.

Chris Mason, chair of regenerative medicine bioprocessing at University College London, called the study's approach "the most simple, lowest-cost and quickest method" to generate "pluripotent" cells - those able to develop into many different types - from mature cells.

"If it works in man, this could be the game changer that ultimately makes a wide range of cell therapies available using the patient's own cells as starting material," Mason said. "The age of personalized medicine would have finally arrived."

Earlier this year, German scientists reported their own research breakthough when looking at how to treat leukemia with stem cells.

mkg/msh (Reuters, AFP, AP)