Stem cell pioneer

Jessica Pasley
Published: October, 2007

On March 11, 2007, John Plummer, a 63-year-old English professor of Vanderbilt University, became the first person in Tennessee to undergo a novel therapy to repair his heart.

John Plummer, Ph.D.
Photo by Susan Urmy
About a week after suffering a heart attack, doctors at Vanderbilt University Medical Center siphoned off some of his bone marrow, then shipped the sample off to Amorcyte, Inc., a New Jersey-based biotechnology company that is developing cell therapy products to treat cardiovascular disease.

After processing and enriching the sample to promote the development of stem cells, the company sent the sample back to Vanderbilt, where it was injected into Plummer’s coronary artery, from where preliminary studies suggest the cells will diffuse into the his heart muscle.

Plummer, who has taught at Vanderbilt for 36 years, said that while he realized there are no guarantees, “it was the prospect of improvement—any improvement—that made it worth it.”

Vanderbilt is one of three centers, along with Emory University in Atlanta and Texas Heart Institute in Houston, participating in the Phase 1 clinical trial sponsored by Amorcyte. The trial, which began last November, is testing whether bone marrow stem cells can aid the recovery and regeneration of heart muscle following a heart attack.

Vanderbilt also is part of the Cardiac Cell Therapy Research Network, sponsored by the National Heart Lung and Blood Institute (NHLBI).

The network, which includes the Texas Heart Institute, University of Minnesota, University of Florida and the Cleveland Clinic, , and is expected to launch the United States into the international field of cardiac will implement phase 2 studies in patients with cardiac disease to explore the effects of cell therapies on the regeneration of the heart muscle.

One of the major obstacles in treating patients after a heart attack is the inability to repair the damaged muscle. In about 20 percent of heart attack patients, the muscle loss is permanent, which leads to worsening of the heart function and, ultimately, heart failure.

“We can treat a lot of diseases affecting the heart… (but) we have not made significant strides in the fact that we can do nothing more than treat symptoms in patients with a dying heart,” said David Zhao, M.D., director of the Vanderbilt Cardiac Catheterization Laboratory.

“What we hope is to one day be able to treat the entire heart without surgery, and use the bone marrow cells to repair the heart,” Zhao said.

“Heart failure has a huge financial impact on our medical system,” added Scott Phillips, M.D., a cardiology fellow who is participating in the Vanderbilt study. “… If this proves to be a viable therapy, there would be tremendous benefits, not only for the patient, but in terms of the amount of money a health care system could save. It would be astronomical.”

The premise behind cardiac regenerative therapy is this: Bone marrow is rich in endothelial progenitor cells, which circulate in the blood and are thought to facilitate the growth of new blood vessels. European scientists for several years have pioneered approaches aimed at using these primitive or “stem” cells to try to repair heart damage.

“This treatment approach looks very promising based on preliminary results already published,” said Friedrich Schuening, M.D., chief of the Section of Hematology and Stem Cell Transplant at Vanderbilt.

The Amorcyte trial is enrolling patients with evidence of impaired heart function following a heart attack. Half of the participants in the study will receive a stem cell infusion, while the others will serve as a control, and will receive standard treatment.

They will be followed regularly for up to five years. Assessment tools, aside from a clinical visit, will include echocardiograms (EKGs) and cardiac magnetic resonance imaging (MRI), which can reveal in detail the ventricular structure and function of the heart.

Within three to six months, investigators expect to see some improvement in heart function.

“This is an exciting opportunity to get into the field of regenerative medicine of the heart,” said Douglas Vaughan, M.D., former chief of Cardiovascular Medicine at Vanderbilt.

“We don't have all the answers about cardiac cell-therapy, but we do know that we have to start doing these trials to start finding the answers to the questions.”

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