Potential for adult stem cells to repair hearts damaged by severe coronary artery disease
(2 February 2007: VIDYYA MEDICAL NEWS SERVICE) -- Rush University Medical Center is one of the first medical centers in the country, and currently the only site in Illinois, participating in a novel clinical trial to determine if a subjectís own stem cells can treat a form of severe coronary artery disease.
The Autologous Cellular Therapy CD34-Chronic Myocardial Ischemia (ACT34-CMI) Trial is the first human, Phase II adult stem cell therapy study in the U.S. designed to investigate the efficacy, tolerability, and safety of blood-derived selected CD34+ stem cells to improve symptoms and clinical outcomes in subjects with chronic myocardial ischemia (CMI), a severe form of coronary artery disease.
"What weíre hoping is that these stem cells will be able to stimulate the growth of new blood vessels to bring more blood and oxygen to the heart muscle, so that these patients will have a better quality of life and less chest pain," said Dr. Gary Schaer, director of the Rush Cardiac Catheterization Lab and study investigator.
Myocardial ischemia is a serious heart condition that involves narrowing of coronary arteries and results in limited blood flow to the heart. The disease affects hundreds of thousands of new people each year. A person who suffers from chronic myocardial ischemia continues to experience insufficient flow of oxygen-rich blood to the heart despite optimum medical intervention.
The study is a randomized, double-blind, placebo-controlled study that involves adult subjects with severe coronary artery disease who are currently on the maximum medical therapy and who are not suitable candidates for conventional procedures to improve blood flow to the heart such as angioplasty, stents, or coronary artery bypass surgery.
Rush is one of 15 to 20 research sites nationwide participating in the study, which is sponsored by the Cellular Therapies business unit of Baxter Healthcare Corporation. Baxter technology is used to select the subjectís own CD34+ stem cells that are under investigation in this trial.
The baseline frequency and severity of anginal episodes are established as a first step for all study subjects. Next, all subjects receive a series of subcutaneous injections (needle shots, typically delivered under the skin in the arm, thigh or abdomen) of a commercially produced protein (granulocyte colony stimulating factor). The protein helps to release CD34+ stem cells (also known as endothelial progenitor cells) from a subjectís bone marrow into the bloodstream.
Then, investigators use a cell separation system, similar to the automated systems that are used with people who donate specific blood components such as platelets or red blood cells, to collect from the subjectís bloodstream, an enriched preparation of cells that contain CD34+ stem cells. When this process, known as apheresis, is complete, technologists further process the collected stem cells with Baxterís ISOLEX 300i Magnetic Cell Selection System, currently approved for use with cancer patients, to select the subjectís CD34+ stem cells for use in this investigational therapy.
Schaer then uses a catheter-based, non-surgical system to map the patientís heart three-dimensionally to identify the damaged areas into which the stem cells would be injected. "This targeted approach increases the treatment's effectiveness by delivering the stem cells exactly where they are needed." Schaer uses the Johnson & Johnsonís NOGA XP Cardiac Navigation System to identify ischemic but viable regions of the heart as targets for cell delivery. The researchers then use a special investigational catheter that functions like a "global positioning system" to precisely deliver CD34+ cells, or placebo, into the areas of the heart that have been identified as having poor blood flow.
Subjects are randomly selected to receive either one of two dosing levels of CD34+ stem cells, or placebo. Rush researchers will conduct follow-up examinations for 12 months,
Researchers are encouraged by reports that the therapy appeared to be well-tolerated and no serious adverse events directly related to the stem cell therapy in an earlier study. According to preliminary, anecdotal patient reports, 16 of the 24 total Phase I study subjects reported feeling better with reductions in chest pain and improved exercise capacity during the early stage of the trial.
Coronary Artery Disease and Chronic Myocardial Ischemia
Coronary artery disease is the most common form of heart disease and is the leading cause of death in the United States. This condition occurs when the coronary arteries and the smaller vessels that supply oxygen-rich blood to the heart muscle become narrowed or blocked
by plaque deposits and blood clots. Poor blood flow and blood clots "starve" and injure the heart muscle.
The American Heart Association estimates that every year, between 125,000 and 250,000 individuals with coronary artery disease develop chronic myocardial ischemia (CMI), one of the most severe forms of coronary artery disease, which can cause unstable angina, heart attacks and progressive heart failure when adequate blood flow is not restored. CMI develops when the coronary arteries become so diseased that they limit the flow of blood to the heart and send small blood clots downstream, blocking the small blood vessels in the heart. These blockages can result in a series of mini-heart attacks that, while they may be too small to notice at the time, in aggregate cause significant long-term damage to the heart muscle and disability to the patient. While cardiologists can restore blood flow in some cases, the heart muscle can be irreversibly damaged, leading to significant disability, progressive heart failure and often death.
What are stem cells?
Stem cells, which have the potential to develop into many different cell types in the body, act like a repair system for the body. They theoretically can divide without limit to replenish other cells as long as the person or animal is alive.
When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.
Source: National Institutes of Health
To participate in the study
For more information, please email research coordinator Catherine_Glase@rush.edu or call (312) 942-8901. The trial is open to adult patients who have daily chest pain but are not suitable candidates for conventional procedures to improve blood flow to the heart, such as angioplasty, stents, or bypass surgery. Participants must be able to do a treadmill exercise test..
About the NOGA Navigation System
The NOGA system is the most advanced technology currently available on the market to create highly precise, 3-dimensional images of the heart. Based on these images, physicians are able to accurately identify tissue that could potentially benefit from a variety of targeted investigational therapies. Built on a proprietary magnetic reference system that operates like a global positioning system, the NOGA XP enables physicians to view the treatment area in a 3D reconstruction that represents real anatomy and provides accuracy of the site being mapped within 1 mm. These highly precise images assess heart tissue with pinpoint specificity, identifying areas for therapeutic targeting.
The innovative technology offers remarkably consistent and precise tissue characterization available, which has a significant importance for intramyocardial delivery of stem cells and genes in cardiac patients. Features such as reduced mapping time made possible by QWIKMAP Software and universal data portability that enable one to download the cardiac maps are vast improvements over existing technologies.
The NOGA XP Cardiac Navigation System is currently being used to map the heart in more than 17 ongoing clinical studies worldwide, investigating the use of adult stem cell and gene therapies to treat conditions such as congestive heart failure and chronic ischemia.
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