Creating new blood vessels - angiogenesis - is very important to our recovery. Any new neurons from neurogenesis or stem cells needs a blood supply in order to stay alive.
http://www.alphagalileo.org/ViewItem.aspx?ItemId=124830&CultureCode=en
Researchers at the University of Helsinki believe they have
discovered stem cells that play a decisive role in new blood vessel
growth. If researchers learn to isolate and efficiently produce these
stem cells found in blood vessel walls, the cells offer new
opportunities in the treatment of cardiovascular diseases, cancer and
many other diseases. The study will be published in the PLOS Biology
journal on 16 October 2012.
The growth of new blood vessels, also
known as angiogenesis, is needed in adults when repairing damaged
tissue or organs. Unfortunately, malignant tumours are also capable of
growing new blood vessels to receive oxygen and nutrients. In other
words, the treatment of diseases would benefit from two types of
methods: ones that help launch the process of angiogenesis and ones that
make it possible to prevent the process. Medications that prevent the
growth of new blood vessels have already been introduced, but their
effectiveness and long-term efficacy leave much to be desired.
For
more than a decade, Adjunct Professor Petri Salvén from the University
of Helsinki has studied the mechanisms of angiogenesis to discover how
blood vessel growth could be prevented or accelerated effectively. He
has examined the birth and origin of endothelial cells, which form the
thin layer that lines the interior surface of blood vessels. Endothelial
cells are necessary for new blood vessel growth. Where do these highly
diversified cells come from? Can their production be prevented or
increased?
For a long time, it was assumed that new cells in the
blood vessel walls of an adult originate in the bone marrow. In an
article published in the PNAS journal in 2008, Salvén’s research team
showed that such stem cells were not found in bone marrow.
Now
Salvén is ready to reveal where these mysterious stem cells originate.
His team’s new study will be published in the PLOS Biology journal on 16
October 2012.
“We succeeded in isolating endothelial cells with a high rate of
division in the blood vessel walls of mice. We found these same cells in
human blood vessels and blood vessels growing in malignant tumours in
humans. These cells are known as vascular endothelial stem cells,
abbreviated as VESC. In a cell culture, one such cell is able to produce
tens of millions of new blood vessel wall cells,” Salvén explains.
“Our study shows that these important stem cells can be found as
single cells among ordinary endothelial cells in blood vessel walls.
When the process of angiogenesis is launched, these cells begin to
produce new blood vessel wall cells.”
The effects of new
endothelial stem cells have also been tested in mice. The results show
that the growth of new blood vessels weakens and the growth of malignant
tumours slows if the amount of these cells in the organism is below
normal. Correspondingly, a high number of new blood vessels quickly
emerge where new stem cells are implanted.
Identifying stem cells among other blood vessel wall cells is
challenging and time-consuming. Salvén and his team managed to identify a
few molecular surface structures that make it easier to trace these
stem cells. However, the efficiency of the identification process needs
to be enhanced.
“If we can find more molecules that are characteristic of the surface
structure of these rare cells, it is possible that we can increase the
efficiency and accuracy of the cell isolation process by more than
tenfold. This would enable numbers that are sufficient for cell
transplant treatments for humans,” says Salvén.
Plenty of potential treatment applications
“The identification and isolation of an entirely new adult stem cell
type is a significant discovery in stem cell biology. Endothelial stem
cells in blood vessels are particularly interesting, because they offer
great potential for applications in practical medicine and the treatment
of patients,” says Salvén.
If an efficient method to produce
endothelial stem cells can be developed, they will offer new treatment
opportunities in situations where damaged tissue or diseases call for
new blood vessel growth or where the constriction or dysfunction of
blood vessels deprives tissues of oxygen. These cells also offer new
opportunities for developing medications that seek to prevent new blood
vessel growth in malignant tumours.
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