What Are Stem Cells?
Stem cells are the only cells in your body that can make different kinds of cells.
Some stem cells can multiply or make more of themselves or other types of specialized cells that make up your blood, brain, muscles, bones, and more. Other stem cells have less potential for self-renewal and can't make as many types of cells.
Stem cells are currently used to treat certain blood conditions and blood cancers. Researchers study stem cells to learn if these basic building blocks of life can help unlock new medical treatments. They can also shed light on why certain health conditions and diseases happen.
Because stem cells may be a way to replace diseased or damaged cells, the hope is that research could one day lead to breakthroughs in treatment for conditions such as:
Researchers are also looking into the role that certain stem cells might play in helping drugmakers test the safety and effectiveness of medications. The idea is that they’d be changed in the lab to become like the specialized cells a given drug targets. Researchers could then test the drug on those specialized cells to see if it works.
Why Are Stem Cells Important?
Stem cells are important because of their potential in future research.
Cell-based therapies. Cell-based therapies, also known as a type of regenerative medicine, hold the promise of repairing or even replacing damaged or diseased organs. A relatively small number of stem cells taken from the body can be grown in the laboratory until they have created millions and millions of new stem cells. This makes it possible for researchers to explore cell-based therapies.
Understanding of disease development. Watching stem cells grow and change into other types of cells can help researchers understand how diseases happen.
Testing. Stem cells can also allow researchers to test new drugs to see how effective they can be and if they are safe. They can perform these tests before they are used in clinical trials.
Types of Stem Cells
There are two main types of stem cells: embryonic and adult.
Embryonic, or pluripotent, stem cells
The embryo is made up of stem cells called embryonic stem cells that divide over and over again and have the potential to make every type of cell in the body.
Researchers have learned to take embryonic stem cells from donated, unused embryos developed during in vitro fertilization (IVF) to make more embryonic stem cells.
Because these stem cells can become any type of cell in the body, they can be used to repair tissues and organs affected by disease.
Adult stem cells
Despite the name, adult stem cells are found in babies, children, and adults. There are two types of adult stem cells.
Tissue-specific stem cells. These are relatively rare and are not as versatile as embryonic stem cells because they usually make cells only for the organ or tissue where they’re located. For example, an adult stem cell in the skin would make more skin cells. Researchers are studying the ability of adult stem cells to create various types of cells.
In the U.S., the only stem cell treatment the FDA has approved is a product called Hemacord, which contains blood stem cells derived from cord blood. The product is approved for people with diseases that affect their ability to make new blood cells, such as certain blood cancers and immune disorders.
Induced pluripotent stem (iPS) cells. Scientists can change adult stem cells in the lab to make them act more like embryonic stem cells. These are called induced pluripotent stem cells. These disease-specific stem cells help researchers study the cause of a certain illness. They can then test drugs or discover other ways to treat or cure that illness.
Stem Cells Treatment
The only stem cell-based treatments (bone marrow transplants) that the FDA has approved are made of blood-forming cells that come from umbilical cord blood. They’re approved for use in people with disorders that affect their body’s ability to make blood. Doctors also use stem cells from bone marrow for these treatments; however, the FDA generally doesn’t regulate them for that use.
A stem cell transplant can be a treatment for conditions such as:
Stem cell transplants can also help replace bone marrow cells destroyed by cancer or cancer treatments, such as chemotherapy and radiation.
What’s more, doctors can treat some diseases or injuries that affect bones, skin, and the cornea (the outer layer of your eye) by grafting tissues that come from or are maintained by stem cells.
Are stem cell treatments safe?
Potential dangers include:
- As stem cells renew themselves and can become different kinds of cells, they might become cancer cells and form tumors.
- Stem cells grown in the laboratory, or adult cells reprogrammed to be stem cells, might have genetic damage.
- Embryonic stem cells might not function in a person's body, and in these cases, the outcomes are unknown.
- A person's body might attack the embryonic stem cells, treating the cells as an unknown threat.
There is also risk in some of the procedures used to get stem cells out of the body (such as from liposuction or spinal tap) or to deliver stem cells to the body (such as implanting them in the heart, brain, spinal cord, or other organs). The risk is not so much about the stem cells, but because of the procedures.
Is Stem Cell Research Legal in the U.S.?
Yes, but each state’s laws are different. Some states encourage embryonic stem cell research, but many have different restrictions in place. States that specifically allow embryonic stem cell research have set up guidelines for scientists, such as consent rules and approval and review procedures for projects.
Stem Cell Research Challenges
Adult stem cell research has been going on for decades, but scientists have much more to learn about embryonic stem cells. They’ve only been studying them since 1998.
If researchers get a clearer idea of how embryonic stem cells form, it could help them understand how to control the cells made from them. But, for ethical reasons, some people aren’t comfortable with the idea of using stem cells that come from embryos.
Another challenge is that many researchers find it hard to grow adult pluripotent stem cells in the lab. These cells are present in small amounts throughout the body, but there is a higher chance that they could have DNA problems.