Healing a Damaged Heart Without the Need for Stem | Arthritis Information
Healing a Damaged Heart Without the Need for Stem Cells
By
Madeline EllisPublished: Saturday, 25 July 2009
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Experts claim that once a heart is damaged, it is nearly impossible to fix.
Surgical techniques
can repair blood vessels and heart valves can be replaced, but once the
heart muscle is damaged, there is no known way for it to heal on its
own, in part because the cells called
cardiomyocytes
that are responsible for the development of heart muscle stop dividing
and proliferating shortly after birth. However, researchers at
Children’s Hospital in Boston say they have been able to restart that
cell cycle and reverse heart damage in mice—without using stem cells.
What
they used is known as neuregulin 1 (NRG1), a protein which is essential
for the initial development of the nervous system and the heart.
Beginning a week after experiencing laboratory-induced heart attacks,
live mice were given daily injections of NRG1 for 12 weeks, after which
they showed evidence of improved pumping function, reductions in heart
muscle scar size, and an increase in heart muscle cells. They also
showed no signs of heart failure, such as dilation of the heart
chambers and thickening of the heart muscle. “Most of the (heart
attack) related cell death had already occurred,” said lead researcher
Dr. Bernhard Kuhn. “When we began the injections we saw replacement of
a significant number of cardiomyocytes resulting in significant
structural and functional improvements in the heart muscle.”
The ultimate goal will be to one day use NRG1 as a therapy for heart attack patients, those with
heart failure
or children with congenital heart defects. It may also be used in
conjunction with another protein, periostin, which is found in the
developing fetal heart and in injured skeletal muscle but scarce in
adult hearts, identified by Dr. Kuhn and colleagues in 2007. Periostin
also promoted heart muscle cell growth and improved heart function in
rats, but it cannot be injected. So the researchers developed
sponge-like patches that they soaked in the compound and then placed
directly on the damaged area of the heart of rats. “During initial
treatment, patients might receive neuregulin injections, and once they
are stable and out of the ICU, they might be taken to the cath lab for
the periostin patch,” Dr. Kuhn said.
But first, both
treatments must be proven safe and effective in large animal and human
studies. The researchers recently completed a study of periostin in
pigs, which have more in common with humans than rodents do, and the
protein is now in preclinical development at Children’s Hospital for
future application in human patients with heart failure.
Many other researchers are also looking for ways to repair damaged heart muscle, but most of these efforts have focused on the
use of stem cells.
However, Dr. Kuhn says these proteins could provide another option.
“Collectively, we have identified the major elements of a new approach
to promote myocardial regeneration,” he said. “Many efforts and
important advances have been made toward the goal of developing
stem-cell based strategies to regenerate damaged tissues in the heart
as well as in other organs. The work presented here suggests that
stimulating differentiated cardiomyocytes to proliferate may be a
viable alternative that could be developed into a simple strategy to
promote myocardial regeneration in mammals.”
Professor Jeremy
Pearson, British Heart Foundation (BHF) Associate Medical Director,
called the new study “fascinating” and said “if the same mechanisms
identified by the researchers can be shown to work in the human heart,
it opens up real possibilities for new and more efficient ways to treat
people with heart disease.” He added that “up until now, adult heart
cells have been widely believed to be incapable of replication.”
A report on the research appears in the July 24 issue of
Cell.
http://www.healthnews.com/medical-updates/healing-a-damaged-heart-without-need-stem-cells-3493.htmIt seems they are making so much progress on medicine in every area. I may have to stop worrying about my health and find something else to worry about.
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