When a needle in the heart can help
Adult stem cell injections meant to heal damaged cardiac muscle
By TODD ACKERMAN
Copyright 2008 Houston Chronicle
Houston researchers have launched an experimental trial in which
primitive adult stem cells are injected directly into the hearts of
heart attack victims, an attempt to prevent heart failure from
developing.
The research, based on the remarkable ability of human stem cells to
grow into almost any tissue, has enormous implications for the nearly
1 million Americans who survive heart attacks annually. For many, the
damage leads to a progressive and often fatal weakening of the heart.
"Our expectation is that the stem cells will develop into blood
vessel and heart muscle cells and heal the damage caused by the heart
attack," said Dr. James Willerson, president-elect of the Texas Heart
Institute, the site of the study. "People should be excited by this."
Willerson, also president of the University of Texas Health Science
Center at Houston, said he hopes the therapy can become accepted
treatment in five or so years. It is also being tested, with slightly
different approaches, at other institutions.
Treatment with adult stem cells was considered unthinkable not that
long ago, but it is increasingly becoming an option as researchers
discover the cells have properties previously thought to belong only
to embryonic stem cells.
On Friday, THI researchers announced they'd discharged the first
patient in the new trial, a 65-year-old man who was injected with the
stem cells on Wednesday, 10 days after suffering a massive heart
attack. They plan to enroll 24 more patients.
The research builds on previous THI work treating heart disease with
adult stem cells. That work, conducted initially in Brazil and then
in Houston, used the patients' own stem cells to treat their already
advanced heart failure.
Willerson stressed that the idea for the new study is to attack heart
problems before they develop into congestive heart failure, the
condition when the weakened heart can't pump enough blood to meet the
body's needs. About 30 percent of heart attack victims develop heart
failure, 50 percent if it's a large attack involving the heart's
front wall.
No danger of rejection
In all, more than 5 million Americans live with heart failure and
550,000 new cases are diagnosed annually.
The new study also differs from THI's previous work because it
involves stem cells taken from the bone marrow of a donor. Known as
mesenchymal precursor stem cells, the cells are considered to have
greater plasticity than other adult stem cells. Harvested from the
donor's bone marrow — they are not easy to identify — they are then
grown in cultures, providing an abundant supply.
They do not pose any rejection issues by the patient's immune system,
researchers said.
"It's great to hear of another study in this promising and exciting
field," said Dr. Joshua Hare, director of the Interdisciplinary Stem
Cell Institute at the University of Miami School of
Medicine. "Questions about what's the best cell, the best way to
deliver the cells and how the cells work can only be answered by
doing a number of studies like this."
Hare led a multi-institutional study, reported last year, that found
mesenchymal stem cells given to heart attack patients improved heart
function and lower rates of problems such as cardiac arrhythmias.
The cells, slightly different from the ones THI will use, were
injected into the veins but migrated to sites of tissue damage in the
heart.
In the Texas Heart Institute trial, the cells are injected directly
into the heart through a catheter inserted at the groin. Injections
are made at sites where the heart attack damaged muscle.
The trial's 25 patients will be enrolled in three phases, with the
amount of stem cells injected increasing in each phase. Willerson
said he hoped all 25 could be enrolled within a year.
Early results look positive
The heart institute will partner with Houston-area hospitals to bring
to it patients with less than 45 percent heart function remaining
after a heart attack. The injections are to be given 10 days after
the attack.
Heart institute researchers are expected to announce results of the
U.S. study using patient's own stem cells to treat their advanced
heart failure soon, but they said they look positive. The study of
patients in Brazil found those given stem cells had better blood flow
and oxygen utilization than those who didn't get the cells.
"I think this is the most exciting stem-cell therapy in heart
research today," said Dr. Emerson Perin, director of the Stem Cell
Center at the Texas Heart Institute at St. Luke's Episcopal Hospital
and the study's other leader. "Because these new cell types are so
powerful and they delivered directly to the heart damage, it should
be great at promoting healing."
todd.ackerman@
http://www.chron.
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StemCells subscribers may also be interested in these sites:
Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
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