Potential Advance in Reversing Heart Failure?

I certainly don't want to raise any false hopes, but this recent work
at Harvard University and Charité Universitätsmedizin Berlin might
lead to radically new and powerful methods for reversing heart failure
and some other heart diseases.

Those who are familiar with the journal "Nature" (and its associated
sub-journals) know that it is one of the most prestigious scientific
journals on earth.

The article referenced below is published in the online version of
Nature, June 22, 2008.  The Nature abstract may be viewed here, though
I suspect the full article is not available to non-subscribers:
http://www.nature.com/nature/journal/vaop/ncurrent/abs/nature07060.html

But the summary below may be even better for the non-scientist. If the
treatment can be made to work (not yet proven), it would likely go
through a few stages of testing before it would be widely available.
Even so, it is a very exciting possibility!  (Incidentally, the
results "were independently verified by another team of scientists at
the University of California in San Diego.")

Source: http://www.healthnews.com/medical-updates/researchers-stumble-upon-new-source-he
art-stem-cells-1288.html

Researchers Stumble upon New Source of Heart Stem Cells
By: Madeline Ellis
Published: Friday, 27 June 2008

Today in the United States, congestive heart failure, the ineffective
pumping of the heart caused by the loss or dysfunction of heart muscle
cells, afflicts 4.8 million people, with 400,000 new cases each year.
One of the major contributors to the development of this condition is
a heart attack, known medically as a myocardial infarction, which
occurs in nearly 1.1 million Americans each year.... For those
suffering from heart disease, stem cell biology represents a new
medical frontier; one working toward using stem cells to replace
damaged heart cells and literally restore cardiac function. [Note from
Brett: as I understand it, these stem cells occur within ones own body
-- these are not the stems cells from embryos that have caused such
controversy in recent years.]

In 2006, scientists identified a cardiac stem cell, marked by the
expression of a gene called Nkx2-5, with the potential to become
either heart muscle or cells lining blood vessels in the organ's left-
sided chambers. Simultaneously, other U.S. researchers discovered a
related progenitor heart cell, so-called because of its capacity to
generate different types of tissue that produces the same cell types
in the right-sided heart chambers.

Most recently, quite by accident, U.S. researchers discovered a new
group of stem cells that may one day play a critical role in the
regeneration of injured heart tissue. Located in the outermost layer
of the heart, these stem cells can give rise to heart muscle cells,
known as cardiomyocytes. "In heart failure, you lose cardiomyocytes,
so the only way to reverse heart failure is to make more of these
cells," said William Pu, the study's lead researcher and a pediatric
cardiologist at Children's Hospital in Boston, Massachusetts.

While studying the role of a different gene in the heart's outer
lining, called the epicardium, Dr. Pu and colleagues labeled cells in
live mouse embryos with red fluorescent protein. "Unexpectedly, we saw
that these epicardial cells were becoming cardiomycytes-it was a lucky
observation," said Pu. The researchers showed that the cells can not
only metamorphose into cardiomycytes, but also into smooth muscle
cells, endothelial cells, which line the interior of blood vessels,
and fibroblasts, found in connective tissue. The results were
independently verified by another team of scientists at the University
of California in San Diego.

Pu's findings show that new heart stem cells can also be derived from
a third type of cardiac stem cell, located within the surface of the
organ and identifiable through its expression of a gene called Wt1.
Gene expression is the process by which information encoded in the DNA
of a particular gene is transformed into a protein or RNA, which plays
a key role in protein synthesis.

Pu said the next challenge is trying to figure out how a progenitor
stem cell decides to become a certain type of functioning cell within
the heart, and then how to develop methods to trick the stem cells
into transforming into the desired tissue. "We still don't know how we
can manipulate these progenitors," he said.

Both Pu's and the corroborating study were published on June 22 in the
online journal Nature.

(finis)

Note, the title and citation of the Nature article are:

"Epicardial progenitors contribute to the cardiomyocyte lineage in the
developing heart"
Authors: Bin Zhou, William T. Pu, et al. (Harvard Univ)
Macmillan Publishers Limited. All rights reserved
SN  - 0028-0836
UR  - http://dx.doi.org/10.1038/nature07060

--
Brett
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