Apr 28 2006
Rush cardiologists are hoping that transplanted stem cells can regenerate damaged heart muscle in those who experience a first heart attack. The study involves an intravenous infusion of adult mesenchymal stem cells from healthy donor bone marrow that might possibly reverse damage to heart tissue.
A unique benefit of the stem cell product is that it is given to patients through a standard IV line. Other therapies require delivery to the site of the disease through catheterization or open surgical procedures, but this one is very simple and easy for the patient.
"A person who has had a single, severe heart attack may survive but can be left with substantial damage to the heart muscle as a result of the blood supply to the heart muscle being cut off during the heart attack. The damaged muscle inhibits the heart's overall ability to pump blood, leading to heart failure," said Rush principal investigator cardiologist Dr. Gary Schaer, head of the Rush Cardiac Catheterization Laboratory. Rush is the only center in Illinois participating in the trial. There are 15 other sites nationwide participating in the study.
He explained that mesenchymal stem cells (MSC) are found in the adult bone marrow and have the potential to develop into mature heart cells and new blood vessels. The MSC cells are derived from normal, healthy adult volunteer bone marrow donors and are not derived from a fetus, embryo or animal. Because they are in an early stage of development, it is believed that they do not trigger an immune response when placed in someone else's body.
Similar to Blood Type O, these MSCs are being used without tissue type matching to a specific patient.
Dr. Schaer says the cells are grown in culture to very high numbers, allowing a single donor's cells to treat thousands of patients. "The cells have the ability to expand, or multiply, under controlled conditions, and the expanded cells have the ability to develop into different types of cells in the appropriate environment. One donation can produce billions of MSCs. The cells can be stored for years in a frozen state, ready to be used when they are needed."
Adult stem cells are designed by nature to perform tissue repair in a mature adult. It is believed that these cells can be used in patients unrelated to the donor, without rejection, eliminating the need for donor matching and recipient immune suppression. Once transplanted, the cells promote healing of damaged or diseased tissues.
Research has demonstrated that mesenchymal stem cells follow inflammatory signals or "home" to sites of injury in the body. Schaer says the stem cells know to go to the heart muscle in a patient who has had a recent heart attack.
When MSCs were injected into animals that have not experienced a heart attack, the cells return to the bone marrow where they were originally located. In animals that had a heart attack induced, the MSCs given intravenously followed the signals to the injured section of the heart and aided in repair. These cells have also been studied for different diseases and have been shown to follow inflammatory signals to various areas of the body to aid in repair. The delivered cells are expected to respond to the body's own signals and migrate to the area of injury.
The Phase I study is double blind; two thirds of the participants receive the stem cells and one-third receive a placebo. To be eligible for the trial, patients must have experienced a first heart attack within the past seven days, and are between 21 and 85 years old. Patients are given a pulmonary breathing test, a CT scan and an MRI before the procedure. Patients undergo an MRI at the end of the study to see how much of the diseased heart muscle has been repaired and measure heart function. A patient may stay in the hospital only 2-3 days for observation, and then go home.
The total time commitment for the study is two years.
Congestive heart failure is a common outcome in heart attack patients and is the number one cause of disability in the United States.
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