The heart muscle cells, cardiomyocytes, can be destroyed by the result of hypertension, chronic insufficiency in the blood supply to the heart muscle caused by coronary artery disease, or heart attack.
Two types of cells are important to a normal functioning heart are the vascular endothelial cell and the smooth muscle cell because vascular endothelial cell forms the inner lining of new blood vessels and the smooth muscle cell forms the wall of blood vessels.
Under highly specific growth conditions in laboratory culture dishes, stem cells can be coaxed into developing as new cardiomyocytes and vascular endothelial cells (Kirschstein and Skirboll, 2001). The exploration of capability for embryonic and adult stem cells to develop into these cells types in the damaged heart is to help the patients who have had heart attacks or congestive heart failure to restore their heart functions.
In the research laboratory, researchers often use a mouse model of a heart attack to study new therapies. Few vital discoveries that trigger the interest in the application of adult stem cells to heart muscle repair in animal models have been made by researchers in the past few years (Kirschstein and Skirboll, 2001).
One of the studies have demonstrated by scientist shown that cardiac tissue can be regenerated in the mouse heart attack model through the introduction of adult stem cells from mouse bone marrow (Kirschstein and Skirboll, 2001). These cells were transplanted into the marrow of irradiated mice approximately 10 weeks before the recipient mice were subjected to heart attack thru tying off different major heart blood vessel, the left anterior descending (LAD) coronary artery. The survival rate was 26 percent at two to four weeks after the induced cardiac injury (Kirschstein and Skirboll, 2001).
Besides, the other study done by other researcher, analysis of the region surrounding the damaged tissue in surviving mice showed the presence of donor-derived cardiomyocytes and endothelial cells (Kirschstein and Skirboll, 2001). Thus, the mouse hematopoietic stem cells transplanted into the bone marrow had migrated to the border part of the damaged area, and differentiated into several types of tissue for cardiac repair.
This research indicates that through bone marrow transplantation the mouse hematopoietic stem cells may be delivered to the heart and also through direct injection into the cardiac tissue. Hence, there is another possible therapeutic strategy to regenerate injured cardiac tissue.
