Heart disease continues to rank as the number of killer of people all over the globe. Each year it is estimated that nearly 20-40 million people die from heart disease. The two common heart disorders associated with the highest mortality include congestive heart failure and an acute myocardial infarction. Over the years, many advances have been made in the treatment of heart disease but they all remain palliative. Most treatments only treatment of symptoms of heart disease and do not cure the disorder. When a patient suffers from a heart attack, the heart muscle in many cases is damaged and develops into a scar, which has no pumping ability. Once heart muscle is damaged, it cannot be reversed and despite all the presently available treatments, heart disease is progressive.
One of the major research accomplishments in the past decade has been the identification of human cardiac stem cells. In the years following this exciting discovery, researchers have been able to show that cardiac stem cells can in fact regenerate heart cells over the
course of one’s life. This observation rekindled hope of using stem cells to repair heart muscle damaged after an acute myocardial infarction. It also dispelled the long-held belief that the heart was not capable of repairing its own tissues after injury.
However, it is important to understand that no physician or scientist has been approved by the FDA to conduct stem cell studies in human hearts in the USA. All the work is experimental or done elsewhere.
Since that initial discovery of stem cells, scientists have been trying to come up with ways to help repair or replace damaged heart muscle cell. Today a lot more is known about individual heart cells, how they function and transmit electrical signals. In addition, the biochemistry and metabolism of heart cells is quite well known.
Presently researchers are able to grow embryonic heart cells in the laboratory. These cells have been obtained from heart biopsies performed during surgery. In addition, scientists have also induced-pluripotent stem cells that have been programed to behave like embryonic stem cells, which have the capacity to become any type of heart cell.
Most of the stem cells and research on the heart has been done in the laboratory and the results have been promising. Animal studies show that cardiac stem cells can be used to repair and replace some heart muscle cells, but so far the researchers are not able to determine where these cells reside once they are injected and how they become activated.
Other research has shown the human pluripotent cells may also be useful in the treatment of heart disease. They may also help predict which patients are susceptible to adverse effects of drugs or how they respond to cancer treatment. Similarly, patches of stem cells have been applied with special adhesive glue to damaged areas of the heart to determine if the tissues can be regenerated.
The majority of stem cell studies on the heart have been done in Europe where researchers have injected bone marrow cells into the coronary vessels. Bone marrow cells are known to secrete factors that can help stimulate growth and also modulate the immune system. This is important because when stem cells are transplanted from one person to another, there may not be any need for chemotherapeutic agents. Over 1,000 patients have been transplanted with various populations of bone marrow stem cells for heart disease and so far the procedure has been found to be safe and partially beneficial.
Researchers are now looking at methods of inducing genes or growth factors that can helps stimulate the heart cells to grow. Other research involves use of endothelial progenitor stem cells that line the blood vessels, in the hope of making new vessels that can deliver oxygen to the damaged heart.
Most of the clinical trials are in the very early stages and the results will not be known for a few more years. It is also important to note that already many companies have been promoting use of stem cells for treatment of a variety of heart disorders. Consumers should be aware that these are not FDA approved therapies and there is no evidence that these treatments work, since no clinical trials have been completed. These “fee for service” companies charge thousands of dollars for providing unproven stem cell cures. Until more data are available, the adage, “Buyer Beware” should be heeded well when it comes to stem cell cures.