Cells located in the outermost layer of
the heart can be guided to move deeper inside and help to repair a failing
adult heart, new research indicates.
The cells can be guided deeper into the
heart by a specific protein called thymosin beta 4, which is already known
for its ability to reduce muscle cell loss after a heart attack. This protein
can then instruct the heart to heal itself.
The potential repair cells are known as
progenitors. These are similar to stem cells, in that they are not yet
specialised into any one cell type. Instead they are blank cells that can
change into different cell types depending on the signals they receive
in the body.
Previously it was thought that cells within
the adult heart are in a state of permanent rest and that any progenitor
cells that can contribute to heart tissue repair travel into the heart
from the bone marrow. However researchers at University College London
have demonstrated that beneficial cells actually reside in the heart itself.
The research team studied mice which were
bred to lack thymosin beta 4. They found that the hearts of these animals
did not develop normally. The heart muscle showed early signs of tissue
loss and blood vessel development was poor.
Closer examination revealed that without
this protein, the progenitor cells failed to move deeper into the heart
and change the cells needed to build healthy blood vessels and sustain
"To investigate whether thymosin
beta 4 could have a therapeutic effect on damaged adult hearts, my research
team took cells from the outermost layer of adult mice and grew them in
the lab. We found that, when treated with the protein, these adult cells
have as much potential as embryonic cells to create healthy heart tissue.
This suggests that the protein could have a therapeutic use", explained
lead researcher, Dr Paul Riley.
Current treatments for a damaged heart
are limited by the ability of the adult tissue to respond. By using this
protein to guide progenitor cells from the outer layer of the heart, to
form new blood vessels and nourish tissue, it could be possible to better
repair damaged adult hearts.
"Our research has shown that blood
vessel regeneration is still possible in the adult heart. In the future,
can figure out how to direct the progenitor cells using thymosin beta 4,
there could be potential for therapy based on the patients' own heart cells",
Dr Riley explained.
He said that this process has the added
benefit in that the cells are already located in the right place - within
the heart itself.
"All these cells need is the appropriate
instructions to guide them towards new blood vessel formation that will
help in the repair of muscle damage following a heart attack", Dr Riley
Details of these findings are published
in the journal, Nature.