Stem cells are immature cells, meaning they have the ability to develop into a variety of mature cells, such as red or white blood cells, platelets, heart muscle cells, brain cells, etc.

Recent studies have reported encouraging findings after transplanting stem cells taken from patients’ own bone marrow into heart muscle following a heart attack. For heart failure patients, bone marrow cells have been injected into the heart’s left ventricle. Bone marrow cells are seen to enhance the formation of blood vessels and rebuilding of muscle. Early results have been promising. Some study patients responded so well that they were taken off waiting lists for heart transplantation. Other researchers are seeing that bone marrow implanted into the leg can impact against peripheral arterial disease.

Researchers are also encouraged by the use of muscle cells taken from other parts of the body (e.g., thigh) and injecting them into damaged areas of the heart. It is believed that such skeletal muscle helps to restore the contractile properties of affected heart muscle. Animal studies have found, for example, that vitamin C triggers the transformation of mouse embryonic stem cells to heart muscle cells.

Harvesting and implanting stem cells from a patient’s own bone marrow is known as autologous transplantation. Compared to embryonic stem cells, autologous stem cells are significantly more limited in their ability to develop into different cell types. Embryonic stem cells are more versatile in the cell types they can develop into, but their use in research is controversial and sometimes restricted.

Recent research has indicated that stem cells harvested from amniotic fluid (the liquid that surrounds fetus while it is in the womb) may have similar versatility to embryonic stem cells and are more readily attainable. Amniotic fluid is routinely extracted from the womb during pregnancy in a procedure called amniocentesis. The fluid is then analyzed to diagnose a variety of conditions in the fetus. Scientists have discovered that amniotic fluid-derived stem (AFS) cells – which represent roughly one percent of the cells in amniotic fluid – may be able to produce fat, bone, muscle, blood vessels and nerve cells, much like embryonic stem cells. However, research on AFS cells is still in its infancy and clinical trials have not yet taken place on humans.

Scientists continue to research uses for other, more readily attainable types of stem cells.