In experiments that could open a new era in stem
cell biology, scientists have found a simple way to reprogramme mature
animal cells back into an embryonic-like
state that allows them to generate many types of tissue.
The research, described as game-changing by experts in the field, suggests
human cells could in future be reprogrammed by the same technique, offering a
simpler way to replace damaged cells or grow new organs for sick and injured
Chris Mason, chair of regenerative medicine bioprocessing at University
College London, who was not involved in the work, said its approach in mice was
"the most simple, lowest-cost and quickest method" to generate
cells – able to develop into many different cell 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 – the age of personalised medicine would have finally
arrived," he said.
Similar to embryonic stem cell
The experiments, reported in two papers in the journal Nature, involved
scientists from the RIKEN Centre for Developmental Biology in Japan and Brigham
and Women's Hospital and Harvard Medical School in the United States.
The researchers took skin and blood cells, let them multiply, then subjected
them to stress "almost to the point of death", they explained, by
exposing them to various events including trauma, low oxygen levels and acidic
One of these "stressful" situations was simply to bathe the cells
in a weak acid solution for around 30 minutes.
Within days, the scientists found that the cells had not only survived but
had also recovered by naturally reverting into a state similar to that of an
embryonic stem cell.
These stem cells – dubbed Stimulus-Triggered Acquisition of Pluripotency, or
STAP, cells by the researchers – were then able to differentiate and mature
into different types of cells and tissue, depending on the environments they
were put in.
Wide range of possibilities
"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 Haruko Obokata, who
lead the work at RIKEN.
Stem cells are the body's master cells and are able to differentiate into
all other types of cells. Scientists say that by helping to regenerate tissue
and potentially grow new organs, they could offer ways of tackling diseases for
which there are currently only limited treatments.
Recent experimental research has seen stem cells used to create a functional
human liver and to create beating heart muscle tissue.
There are two main types of stem cells: embryonic ones, harvested from
embryos, and adult or iPS cells, which are taken from skin or blood and
reprogrammed back into stem cells.
kept "alive" outside body in medical first
Because the harvesting of embryonic stem cells requires the destruction of a
human embryo, the technique has been the subject of ethical concerns and
protests from pro-life campaigners.
A new era
Dusko Ilic, a reader in stem cell science at Kings College London, said the
Nature studies described "a major scientific discovery" and predicted
their findings would open "a new era in stem cell biology".
"Whether human cells would respond in a similar way to comparable
environmental cues ... remains to be shown," he said in an emailed
comment. "I am sure that the group is working on this and I would not be
surprised if they succeed even within this calendar year."
Robin Lovell-Badge, a stem cell expert at Britain's National Institute for
Medical Research, said it would be some time before the exact nature and
capabilities of the STAP cells would be fully understood by scientists – and
only then would their full potential in medicine become clearer.
"But the really intriguing thing to discover will be the mechanism
underlying how a low pH shock triggers reprogramming," he said. "And
why does it not happen when we eat lemon or vinegar, or drink cola?"
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