BBC News, James
Gallagher, Health and science reporter, 28 August 2013
Cross-section of miniature human brains termed cerebral organoids |
Related
Stories
- Scientists create 3D digital brain
- Scans to unlock secrets of the brain
- Scientists grow human brain cells
Miniature
"human brains" have been grown in a lab in a feat scientists hope
will transform the understanding of neurological disorders.
The
pea-sized structures reached the same level of development as in a
nine-week-old foetus, but are incapable of thought.
The study,
published in the journal Nature, has already been used to gain insight into
rare diseases.
Neuroscientists
have described the findings as astounding and fascinating.
The human
brain is one of the most complicated structures in the universe.
Scientists
at Institute of Molecular Biotechnology of the Austrian Academy of Sciences
have now reproduced some of the earliest stages of the organ's development in
the laboratory.
Brain bath
They used
either embryonic stem cells or adult skin cells to produce the part of an
embryo that develops into the brain and spinal cord - the neuroectoderm.
This was
placed in tiny droplets of gel to give a scaffold for the tissue to grow and
was placed into a spinning bioreactor, a nutrient bath that supplies nutrients
and oxygen.
A cerebral organoid - the brown pigments are a developing retina |
The
researchers are confident that this closely, but far from perfectly, matches
brain development in a foetus until the nine week stage.
The tissues
reached their maximum size, about 4mm (0.1in), after two months.
The
"mini-brains" have survived for nearly a year, but did not grow any
larger. There is no blood supply, just brain tissue, so nutrients and oxygen
cannot penetrate into the middle of the brain-like structure.
One of the
researchers, Dr Juergen Knoblich, said: "What our organoids are good for
is to model development of the brain and to study anything that causes a defect
in development.
"Ultimately
we would like to move towards more common disorders like schizophrenia or
autism. They typically manifest themselves only in adults, but it has been
shown that the underlying defects occur during the development of the
brain."
The
technique could also be used to replace mice and rats in drug research as new
treatments could be tested on actual brain tissue.
Mindboggling
Mindboggling
Researchers
have been able to produce brain cells in the laboratory before, but this is the
closest any group has come to building a human brain.
The
breakthrough has excited the field.
Prof Paul
Matthews, from Imperial College London, told the BBC: "I think it's just
mindboggling. The idea that we can take a cell from a skin and turn it into,
even though it's only the size of a pea, is starting to look like a brain and
starting to show some of the behaviours of a tiny brain, I think is just
extraordinary.
"Now
it's not thinking, it's not communicating between the areas in the way our
brains do, but it gives us a real start and this is going to be the kind of
tool that helps us understand many of the major developmental brain
disorders."
The team
has already used the breakthrough to investigate a disease called microcephaly.
People with the disease develop much smaller brains.
A much smaller brain develops with microcephaly |
By creating a "mini-brain" from skin cells of a patient with this condition, the team were able to study how development changed.
They showed
that the cells were too keen to become neurons by specialising too early. It
meant the cells in the early brain did not bulk up to a high enough number
before specialising, which affected the final size of even the pea-sized
"mini-brains".
The team in
Vienna do not believe there are any ethical issues at this stage, but Dr
Knoblich said he did not want to see much larger brains being developed as that
would be "undesirable".
Dr Zameel
Cader, a consultant neurologist at the John Radcliffe Hospital in Oxford, said
he did not see ethical issues arising from the research so far.
He told the
BBC: "It's a long way from conscience or awareness or responding to the
outside world. There's always the spectre of what the future might hold, but
this is primitive territory."
Dr Martin
Coath, from the cognition institute at Plymouth University, said: "Any
technique that gives us 'something like a brain' that we can modify, work on,
and watch as it develops, just has to be exciting.
"If
the authors are right - that their 'brain in a bottle' develops in ways that
mimic human brain development - then the potential for studying developmental
diseases is clear. But the applicability to other types of disease is not so
clear - but it has potential.
"Testing
drugs is, also, much more problematic. Most drugs that affect the brain act on
things like mood, perception, control of your body, pain, and a whole bunch of
other things. This brain-like-tissue has no trouble with any of these things
yet."
No comments:
Post a Comment