Over 1 million patients worldwide have been treated with stem cell therapy. This fact should come as no surprise if you already know that researchers have identified at least 73 conditions that stem cells can treat.
What you may not know is that there are 3 different types of stem cell treatments.
To understand the benefits of stem cell therapy, you must first understand how the different kinds of stem cells work. That’s why I’m outlining the 3 types of stem cells plus their uses in modern medicine and research.
Ready to learn more about this promising field? Then keep reading.
3 Different Types of Stem Cells
Currently, there are 3 types of stem cells used to treat diseases like cancer and neurodegeneration. While each type differs from each other, they all share one thing in common: their ability to create new cells.
The ability to differentiate into any cell in the body is called pluripotency, which is rare to find naturally in adults. But there are also cells that can divide into the different types of cells that make up a specific tissue.
Embryonic and induced pluripotent stem cells fall into the former category while tissue-specific stem cells fall into the latter group. Here’s what you need to know about all of them.
Embryonic Stem Cells
Embryonic stem cells are naturally pluripotent and harvested from blastocysts. Blastocysts are hollow balls of cells that form a few days following egg fertilization. Under normal conditions, embryonic stem cells give rise to all the different types of cells in the body.
In that way, these cells act like renewable resources. Researchers use these resources to study human development, disease etiology, and to test drugs and other therapies.
Scientists extract embryonic stem cells from the inner cell mass of blastocysts. The cells themselves usually come from IVF blastocysts that the donor no longer needs. They are subsequently encouraged to grow in laboratory conditions.
These stem cells retain their pluripotency, which means they can be used to generate every single cell type in the body except for the placenta and umbilical cord.
Embryonic stem cells and adult stem cells are the only naturally occurring source of pluripotent cells. But researchers have found a way to transform normal tissue cells into pluripotent stem cells.
Induced Pluripotent Stem Cells
When a stem cell divides, it creates two daughter cells that will do one of two things:
- Divide further into differentiated cells that will become tissues, which make up different organs
- Revert to a pluripotent state to create new kinds of cells, tissues, and organs
Once the cell has differentiated, it can never give rise to a cell with a different function. This means that once a heart cell becomes a heart cell, it can never give rise to a lung cell or a kidney cell.
Induced pluripotent stem cells (iPSCs) are reverse-engineered from differentiated cells to become pluripotent again. While the result isn’t exactly the same as embryonic cells, iPSCs can give rise to every different cell type in the body.
iPSCs are created through genetic manipulation of normal, specialized cells. They’re used to develop and test new drugs and therapies as well as learn about normal development, disease onset, and disease progression.
More importantly, though, they offer a solution in the search for a cell source for medical treatments. Organ donors are rare and we’ve long needed a better way to replace worn out organs. iPSCs are thought to be that better way.
Ideally, induced pluripotent stem cells could eventually be used to make personalized therapy products from your own designer line of cells.
Tissue-Specific Stem Cells
One limitation of embryonic stem cells is that once they differentiate, you must create an iPSC if you want to achieve pluripotency again. Adult AKA tissue-specific stem cells aren’t quite pluripotent, but they are one step from it.
Usually found in the bone marrow and blood, tissue-specific stem cells are specialized. They can become the different cell types specific to the organ where they live. These stem cells are difficult to find, but are known to exist in:
- The lining of the gut
- Bone marrow
The one downfall to tissue-specific stem cells is that they can’t revert to a fully pluripotent state like embryonic cells can. Adult stem cells are limited to creating cells only within their own specialization.
Like embryonic and iPSCs, these stem cells are used to improve knowledge about normal development and what happens to cells after injury and/or disease. However, they also offer insight into the natural aging process.
When introduced to damaged tissues, a tissue-specific stem cell encourages the proliferation of new tissue cells. For instance, bone marrow transplants have been used to replace cells damaged by chemotherapy due to leukemia, lymphoma, and more.
Adult stem cell treatment is already in use for the treatment of cancer.
The Stem Cell Treatment Controversy
Despite the exciting implications for medicine, stem cell treatments are steeped in controversy.
The largest issue comes from the conversation about where these stem cells are coming from. Opponents of stem cell therapies think manipulating and/or harvesting from embryos and fertilized egg cells is unethical.
Another issue is that stem cells and, in particular, iSPCs can grow abnormally. These cells have even been known to specialize spontaneously into differentiated cells the researcher didn’t intend.
A third problem comes from the immune response. When immune cells don’t recognize the introduced pluripotent stem cell, they may attack it. This could lead to an autoimmune response in which immune cells attack normal body cells, too.
Finally, stem cell research is a relatively young field. Skeptics wonder if iPSCs might fail in functioning normally. The consequences of this issue are completely unknown, which is a major drawback for some.
Regardless of these issues, proponents for stem cell treatments think the potential benefits outweigh the cons.
More Health News
Stem cell research is still a burgeoning field of knowledge, which means new information is coming out almost every day.
Want to stay in the know about new stem cell findings and other exciting fields of research? Harcourt Health has all the breaking news you need to keep up to date with the health and medical world.