Scientists have grown miniature human brains
in test tubes, creating a "tool" that will allow
them to watch how the organs develop in the
womb and, they hope, increase their
understanding of neurological and mental
problems.
Just a few millimetres across, the "cerebral
organoids" are built up of layers of brain cells
with defined regions that resemble those seen in
immature, embryonic brains.
The scientists say the organoids will be useful
for biologists who want to analyse how
conditions such as schizophrenia or autism
occur in the brain. Though these are usually
diagnosed in older people some of the
underlying defects occur during the brain's
early development.
The organoids are also expected to be useful in
the development and testing of drugs. At
present this is done using laboratory animals or
isolated human cells; the new organoids could
allow pharmacologists to test drugs in more
human-like settings.
Scientists have previously made models of other
human organs in the lab, including eyes,
pituitary glands and livers.
In the latest work researchers at the Institute of
Molecular Biotechnology in Vienna started with
stem cells and grew them into brain cells in a
nourishing gel-like matrix that recreated
conditions similar to those inside the human
womb. After several months the cells had formed
spheres measuring about 3mm-4mm in diameter.
"The cerebral organoids display discrete regions
that resemble different areas of the early
developing human brain. These include the
dorsal cortex identity – the dorsal cortex is the
largest part of the human brain. They also
include regions representing the ventral
forebrain and even the immature retina," said
Madeline Lancaster, who was first author of the
paper published in Nature, on Wednesday.
Jürgen Knoblich, who was part of the team that
created the organoids, said that tests on the
brain cells in the structures showed that they
were functional.
"Previous models were pieces of small tissue that
aggregated to a decent size but there was no
success, so far, in generating something that
would resemble the cortex in a particular stage
of development."
To show how effective the organoids could be in
illuminating brain disorders, Knoblich and
Lancaster teamed up with neurologists from
Edinburgh University to grow brain tissue that
modelled the developmental disease
microcephaly, a condition where the brain grows
to a much smaller size than normal, leading to
mental disability.
"When I looked at the organoids derived from
the microcephaly patient cells, the immediate
thing I noticed was that [their] overall size was
much smaller than the organoids derived from
control, healthy cells," said Lancaster.
The reason, she said, was that brain stem cells
normally undergo many rounds of cell division
before finally turning into brain cells. But in
microcephaly patients, the stem cells begin
turning into brain cells too early, leading to a
depletion in the overall number of brain cells.
Zameel Cader, a consultant neurologist at the
John Radcliffe Hospital in Oxford, said: "This is a
fascinating and exciting piece of research
extending the possibilities of stem-cell
technologies for understanding brain
development, disease mechanistics and therapy
discovery, as well as hopes for regenerative
medicine."
He said the organoid was "audacious and the
similarities with some of the features of a human
brain really quite astounding".
Cader said one similar feature was "the fact that
a considerable degree of the brain complexity
and patterning is [being] encoded and which
could arise from the DNA of the starting stem
cells without additional external manipulations".
Paul Matthews, a professor of clinical
neuroscience at Imperial College London, said
that what made the observations so exciting was
that cells from the patient with microcephaly
developed into an abnormal organoid with
features analogous to many of those existing in
the patient. "The investigators then showed that
these abnormal features could be 'cured' by
replacing the defective gene."
Knoblich said that the team's goals included
growing larger organoids and modelling more
brain diseases.
At the moment the structures did not grow
larger than a few millimetres in the culture
dishes because nutrients and oxygen could not
reach into the centre of the organoids as they
grew. To grow much bigger the organoids would
need to be equipped with a blood supply of some
kind that could feed their centres.
He added that the organoids were unlikely to
reach the complexity required to model
cognition or any other higher brain function,
and the intention of the research was not to
grow replacement brain parts or an entire brain
in culture.
"I have to be pessimistic about this. The ultimate
complexity of the brain will not allow any
replacement of structures," he said. "In the
adult brain all the parts are intimately
integrated with other areas of the brain. It
would be very hard to repair defects with this."


Source - www.theguardian.com/science/2013/aug/28/miniature-brains-test-tubes-neuroscience

Nothing we nor go hear for Nairaland

See how the brain be like crab...

Very soon dem go start dey grow joyst**k

Very soon dem go start dey grow joyst

Ahh! The rate at which all this people are inventing supernatural things is very alarming oh!! It really shows that we are in End time