[BM] Stem Cells Replace Dead Brain Tissue Stroke-Victim Rats

A "cure" for strokes may soon be a simple as growing new brain tissue



An intriguing new study reiterates the promise that stem cells hold for curing many diseases.
Stem cells in the human body can be transformed into a variety of types
of cells, depending on what biologic agents they're exposed to.
Initially, stem cells were the subject of much more debate as they were
harvested from fetuses, but now scientists are beginning to produce
them in the lab by transforming patients' normal tissue cells into stem cells.

In the recent study, a team led by Dr. Mike Modo of the Institute of
Psychiatry, King's College London investigated replacing stroke-damaged
tissue in rats with new tissue from stem cells. Strokes, caused by
blockages in brain blood vessels lead to dead areas of brain tissue.
Past studies have looked at replacing this dead tissue with stem cells,
which would grow into new brain tissue. However, they have met with
little success.

The new study, though, shows such growth is possible; the cells just
need a scaffolding to grow. In past studies, the cells migrated to
other areas of the brain, making them essentially useless in fixing the
problem. In the new study researchers attach them to a tiny scaffold
made of a biodegradable polymer called PLGA, and coated this
scaffolding in neural stem cells. The result is that the damaged brain
tissue is regrown successfully in just 7 days. The technique has a strong likelihood of being able to be applied in humans.

States Dr. Modo, "We would expect to see a much better improvement in
the outcome after a stroke if we can fully replace the lost brain
tissue, and that is what we have been able to do with our technique.
This works really well because the stem cell-loaded PLGA particles can
be injected through a very fine needle and then adopt the precise shape
of the cavity.”

“In this process the cells fill the
cavity and can make connections with other cells, which helps to
establish the tissue. Over a few days we can see cells migrating along
the scaffold particles and forming a primitive brain tissue that
interacts with the host brain. Gradually the particles biodegrade
leaving more gaps and conduits for tissue, fibres and blood vessels to
move into," Dr. Modo continued.

Magnetic Resonance Imaging (MRI) scans are used in the study to locate
the damaged tissue and the optimal injection site for the
scaffolding/stem cell mix. Subsequent MRI scans track the development
of the brain tissue.

The researchers' next step will be to permeate the growing tissue with
VEGF, a factor which promotes blood vessels to permeate a tissue. This
will help bring blood flow to the developing brain mass, keeping it
alive.

Professor Douglas Kell, chief executive of the Biotechnology and
Biological Sciences Research Council (BBSRC) which funded the project,
states, "Stroke is a leading cause of disability in industrialised
countries. It is reassuring to know that the technology for treating
stroke by repairing brain damage is getting ever closer to translation
into the clinic. This crucial groundwork by Dr Modo and his colleagues
will surely be a solid foundation of basic research for much better
treatments in the future."

Joe Korner, Director of Communications at The Stroke Association (UK)
adds, "This research is another step towards using stem cell therapy in
treating and reversing the brain damage caused by stroke. It is
exciting because researchers have shown they are able to overcome some
of the many challenges in translating the potential of using stem cells
into reality. The potential to reverse the disabling effects of stroke
seems to have been proved. However the development of stem cell therapy
for stroke survivors is still in the early stages and much more
research will be needed before it can be tested in humans or used in
practice. Every five minutes someone in the UK has a stroke and it is
vital that we do all we can to help those affected by stroke."

The new research is published in the journal Biomaterials.
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