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Senior Citizen Health & Medicine
Human Stem Cells Implanted to Grow New Blood Vessels
in Dying Legs
First human trial is for patients at end of
therapeutic road
 Jan. 23, 2008 Two patients facing possible leg
amputation have become the first to be treated by transplanting a
purified form of the subjects own adult stem cells into the leg muscles
with severely blocked arteries in hopes new small blood vessels will
grow and restore circulation in the legs. This was the launch by
Northwestern University Feinberg School of Medicine of the first U.S.
trial of the technique that has worked in laboratory animals.
"They're at the end of the therapeutic road and
they're ultimately facing potential amputation," said Douglas Losordo,
M.D., the Eileen M. Foell Professor of Heart Research and principal
national investigator for the study. "This is hopefully a way to help
them avoid that."
Losordo is director of the university's Feinberg
Cardiovascular Research Institute and director of cardiovascular
regenerative medicine at Northwestern Memorial Hospital.
"The stem cells themselves can assemble into blood
vessels," Losordo said. "They can also secrete growth factors that
stimulate and recruit other stem cells to come into the tissue and help
with the repair. It's an amazing biology we're trying to leverage in
these folks."
He said preclinical studies transplanting stem
cells into the limbs have shown this approach to be effective in mice
and rats. "Based on that, we think it has a good chance of helping
humans," Losordo noted.
"This is a dreadful disease in which the profession
has failed to offer much in the way of relief for these patients,"
Losordo said. "We're hoping this will have some impact."
The first two subjects in the 20-site national
trial recently underwent the stem cell transplant process at
Northwestern Memorial Hospital.
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What is Critical
Limb Ischemia?
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Critical Limb Ischemia or CLI is a severe obstruction of
the arteries which seriously decreases blood flow to the
extremities (hands, feet and legs) and has progressed to
the point of severe pain and even skin ulcers or sores.
Critical Limb Ischemia (CLI) is often present in
individuals with severe peripheral arterial disease
(PAD). The pain caused by CLI can wake up an individual
at night. This pain, also called "rest pain," can be
relieved temporarily by hanging the leg over the bed or
getting up to walk around.
CLI is very severe condition of (PAD) and needs
comprehensive treatment by a vascular surgeon or
vascular specialist. This condition will not improve on
its own!
>> Vascular Disease Foundation
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Severely blocked arteries in the leg and sharply
diminished blood flow can result in wounds that don't heal, the
breakdown of tissue and gangrene. This painful condition is called
critical limb ischemia (CLI) and results in the amputation of more than
100,000 limbs every year in the United States.
It's a serious, emerging health problem that
affects 1.4 million people. An estimated 15 percent of the population
will have this disease by the time they reach age 70.
The Northwestern-led phase I/IIa study - which will
include 75 people with CLI around the country - targets patients who
have exhausted all other medical options including angioplasty, stents
and bypass surgery to repair blocked circulation in their legs.
Critical limb ischemia is the result of advanced
peripheral artery disease, which affects about 10 million people in the
United States. In peripheral artery disease, people develop blockages in
their arteries and vessels that slow or stop the blood flow to their
legs.
When they have pain at rest in their lower legs and
wounds on their legs or feet that will not heal, the condition is called
CLI. If left untreated, CLI can result in a patient having toes, a foot
or even a leg amputated.
As CLI progresses, people begin to experience pain
when they walk, then when just sitting. The worst pain is at night
because blood flow is decreased when people lie down. Some have to sleep
in chairs to aid the blood flow and lessen the pain.
"Peripheral artery disease is a big health
problem," Losordo said. "There is an emerging awareness of this disease
on public health."
High blood pressure, high cholesterol, smoking and
diabetes all raise the risk of having the condition. But some people
don't smoke, have diabetes or high blood pressure and can still have
blocked arteries in their legs, Losordo said.
For the randomized, double blind,
placebo-controlled trial, Losordo uses the subject's own purified stem
cells. The subject first takes a drug for five days to stimulate the
release of his or her stem cells, called CD34+ cells, from bone marrow.
An intravenous line is then inserted into a subject's vein to collect
blood through a machine that removes a population of blood cells that
contains the CD34+ stem cells. Losordo further selects and enriches the
cells to select only CD34+ cells.
Editors Notes:
Losordo's study is supported by Baxter Healthcare
Corporation, which manufactures the Isolex 300i Magnetic Cell Selection
System machine used in this investigational study. The Isolex 300i
Magnetic Cell Selection System, which is approved for use in oncology
patients, purifies the subject's stem cells to provide only the CD34+
stem cells. Losordo is also a paid consultant to Baxter.
>> Read "Grow
new arteries to banish leg pains," Daily Mail (UK)
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