How Does Stem Cell Treat Diseases?

When most people think of disease-treating stem cells, they think of a transplant of stem cells.

Embryonic stem cells are first specialized in the required type of adult cell in a stem cell transplant. These mature cells then replace tissue damaged by illness or injury. This type of treatment could be used to replace neurons damaged by spinal cord injury, stroke, Alzheimer's disease, Parkinson's disease or other neurological problems; produce insulin that can treat people with diabetes and heart muscle cells that can repair damage after a heart attack or replace virtually any tissue or organ that is injured or diseased.

However, much more can be done by embryonic stem cell therapies. Studying how stem cells develop into heart muscle cells could provide clues as to how after a heart attack we could induce heart muscle to repair itself. The cells for toxic side effects could be used to study disease, identify new drugs, or screen drugs. Without transplanting a single cell, any of these would have a significant impact on human health.

In theory, the types of diseases that might be treated with stem cell research are not limited. Because researchers can use embryonic stem cells to study all cell types, they have the potential to make breakthroughs in any disease. In recent years, many clinical trials have started for embryonic stem cell-based therapies. Results from those will not be available until the trials reveal that the therapies are safe and effective— which could take several years to complete.

While ten cell therapies have been approved worldwide since January 2016, bone marrow transplantation is the only widely used stem cell therapy. The first stem cells to be identified were blood-forming stem cells in the bone marrow and were the first to be used in the clinic. This life-saving technique has helped thousands of people around the world who have suffered from cancers of the blood, like leukemia.

Research suggests that, in addition to their current use in cancer treatments, bone marrow transplants will be useful in treating autoimmune diseases and helping people tolerate transplanted organs. Other adult stem cell-based therapies are currently undergoing clinical trials. We won't know which type of stem cell is most effective in treating various diseases until these trials are complete.

When the first human embryonic stem cell therapies become widely available, there is no way to predict. Several applications have been approved with the FDA to start human trials of embryonic stem cell-based therapies. Overall, the path to widespread use from the first human trial is on the order of a decade. That long time frame is the result of the many steps that therapy must take to demonstrate that it is both safe and effective. The FDA will only approve stem cell therapy for general use once these steps have been completed.