Almost six million Americans have congestive heart failure (CHF), a cardiovascular disease that inhibits the heart from pumping blood throughout the body, with 550,000 new cases diagnosed each year. About half of these patients die within five years after receiving a diagnosis of severe heart failure.

Physician scientists at the Texas Heart Institute (THI) at St. Luke's Episcopal Hospital (Houston) reported the initial results of what they says is the world's first clinical trial to treat heart attack patients with a type of stem cell that promotes better healing while also acting to stave off CHF which many patients develop following a heart attack.

Stem cells are commonly referred to as "generic" cells that can regenerate themselves and develop into specialized cells, such as cardiac cells. In stem cell therapy, the stem cells are typically removed from another part of the patient's body — usually the bone marrow or the blood, both of which contain a variety of stem cell types. The cells are then transplanted into the heart, where they can lead to the growth of new heart muscle and blood vessels to replace damaged tissues.

The stem cells used in this study are known as mesenchymal precursor stem cells. And they are allogeneic, meaning that they have been taken from the bone marrow of a healthy donor and grown in cultures to provide a plentiful supply. This is considered the first use of the allogenic "off the shelf" cells for this application.

These cells are injected directly into the heart with a special catheter, called a noga catheter, and appear not to provoke rejection by the recipient or cause inflammation, according to the researchers.

The study is sponsored by Angioblast Systems (New York), provider of the cells and the U.S. sister company of Mesoblast (Melbourne, Australia.)

James Willerson, MD, president-elect and medical director at THI, told Medical Device Daily that what makes these particular stem cells different is that they are not rejected when taken from a donor and injected into another person.

"If I gave you my stem cells, your body would probably reject them — that's why we try to use the patient's own stem cells. But in this case there is evidence to suggest that these [allogenic] cells are not rejected among different individuals. So we could take the cells from an Olympian, or someone in great health, and inject them directly into the patient's injured heart, and they wouldn't reject them."

Willerson explained that the procedure involves insertion of the noga catheter "via an arterial route. When it touches the inner wall of the heart, it measures electrical potential, and provides an assessment of the wall motion in that particular region of the heart. We can identify sites of the heart that are reversibly injured, as opposed to scar or normal regions. The stem cells are injected directly into those regions."

The first patient to receive the treatment is a 65-year-old male. He had had a heart attack treated with angioplasty to open the obstructed vessel, with placement of a stent.

The stem cell procedure was administered in a catheterization lab 10 days after the heart attack, and he was discharged from the hospital two days after receiving this experimental treatment.

"Our pre-clinical trials have established that 10 days after the heart attack is the optimal time to give this treatment," said Emerson Perin, MD, PhD, director of THI's stem cell center and director of clinical research for cardiovascular medicine at THI.

"The heart is still inflamed in the days just after a heart attack," he noted. "If we wait too late, the heart will have too much scar tissue, and its ability to pump will already be compromised."

Willerson made the point that every person is a product of two cells which develop into billions of stem cells that have the innate ability to form our bodies.

"All of us have stem cells in our bodies, just not in sufficient numbers to perform the healing we need. I believe we were meant to learn of the powerful potential of stem cells and build on it. In the coming years, this could be an accepted stem cell therapy at hospitals. Ultimately, stem cell research could give us the ability to regenerate whole hearts," Willerson said.

Perin and Willerson said that they and their team have developed a network of several hospitals to identify patients who may fit the criteria to be enrolled in this trial.

"We're already seeing promising results from treating patients with severe heart failure with their own stem cells. With this study, we hope to find a way to help patients before they get so sick," said Perin.

Angioblast received FDA approval to launch the stem cell trial last May (MDD, May 7, 2007). The trial is using catheters provided by Angioblast's partners, Cordis (Miami Lakes, Florida) and Biosense Webster (Diamond Bar, California).

Mesoblast and Angioblast also are conducting a pilot clinical trial in Australia using autologous cells as therapy for coronary artery disease (MDD, Sept. 26, 2006).

Also this week Mesoblast reported successful long-term results in its osteoarthritis preclinical trials, presenting its data in Singapore at BioMedical Asia 2008.

A single injection of its proprietary allogeneic adult stem cells into arthritic knees provided sustained protection against cartilage destruction and degeneration for up to nine months, according to the report. And Mesoblast said that, based on these results, it will begin a Phase II clinical trial for cartilage protection in patients with osteoarthritis of the knee.

Professor Silviu Itescu presented the results at a gathering of more than 1,000 biomedical industry executives from Australasia, Asia, the U.S. and Europe.