Stem Cell Therapy for Heart Disease

- Migrate and engraft to damaged heart muscle (4,5)
- Contribute to the formation and proliferation of new blood vessels (4,6)
- Improve left ventricular remodeling, structural damage and function (7)
- Decrease the size of infarction (8)

These animal studies may lay the foundation for future human clinical trials testing cord blood stem cell treatment for patients with heart damage due to myocardial infarction.

Cardiomyocytes and Cord Blood: In Vitro Studies Show Promise

Permanent loss of cardiomyocytes (heart muscle cells) and the formation of scar tissue following a heart attack result in irreversible damage to cardiac function. Human cord blood contains several different types of stem cells including hematopoietic, endothelial and mesenchymal stem cells. Although still in early stages, four in vitro studies have shown that under certain treatment conditions, cord blood mesenchymal stem cells differentiate into cardiomyocyte-like cells (9,10,11,12) and were able to induce regeneration of healthy cells from damaged cardiomyocytes (12). This suggests that cord blood stem cells have a high potential to differentiate into cardiomyocytes and aid the regeneration of cardiomyocytes lost due to heart damage.

Cord Blood and Congenital Heart Defects

Although more research needs to be done, scientists believe cord blood stem cells may have the most immediate benefit for children born with congenital heart defects - or problems with the heart's structure that are present at birth.

According to one in vitro study, cord blood endothelial stem cells demonstrated excellent growth potential for tissue-engineered vascular grafts that could replace human heart defects. These findings offer a compelling reason why parents with a child diagnosed intrauterinely with congenital defects should consider preserving their child's cord blood, since it may offer a treatment option in the future.(13)

Advances in Peripheral Vascular Disease

The ability of cord blood stem cells to become vascular endothelial-like cells and thus, blood vessels, indicates they will likely have potential applications beyond the heart.

Peripheral vascular disease (PVD) is a restriction of blood flow outside of the heart usually occurring in the legs and arms. Restricted blood flow is caused by blood vessel narrowing from fatty plaque formation on vessel walls (atherosclerosis) or blockage due to blood clots. If the blockage is severe enough, tissue death can occur. If left untreated, the limb may need to be amputated.(14)

In animal models, cord blood stem cells have been able to significantly reverse the effects of ischemia, or loss of blood flow in the blood vessels. In models of hind limb ischemia, transplantation of cord blood stem cells appeared to reverse surgery-induced ischemia resulting in limb salvage.(15-16) These observations may lead to future human clinical trials using cord blood stem cells to treat patients with peripheral vascular disease.

The Future of Cord Blood Stem Cell Therapy