How do you make stem cells?
Many have probably heard about stem cells and their enormous potential because of their ability to renew themselves over and over – and replace exactly the type of cells you may need. But where do stem cells actually come from? And how can scientists make new stem cells? We put these questions to stem cell expert Helle Bogetofte Barnkob.
How are stem cells used?
The induced pluripotent stem cells are ‘trained’ by giving them signals that mimic the body’s natural signals during foetal development. By doing so, they are instructed on what to develop into.
For example, into nerve cells, various blood cells or heart muscle cells.
In research, nerve cells are used, among other things, to study diseases such as Alzheimer’s and Parkinson’s disease in living cells. This would not otherwise be possible because it is difficult to take a cell sample from a patient’s brain and use it to grow cells.
By experimenting with living cells, it is possible to examine how to offer patients better methods of treatment.
By experimenting with living cells, it is possible to examine how to offer patients better methods of treatment. For example, is it possible to get the dopamine-producing nerve cells in the midbrain to regenerate so that a patient with Parkinson’s gets better? Or can you make a heart muscle heal itself after a heart attack?
These kinds of questions become easier to answer when you can take a relevant patient’s skin cells, reset them and train them into the type of cells you want to examine. The advantage is that the newly formed cells have the same genetic background as the patient. Therefore, in some respects, the approach also provides more accurate research results than, for example, experiments on mice.
Today, stem cell technology is also used for bone marrow transplants, where, for example, cancer patients receive stem cell treatment based on their own cells.
Where are stem cells found?
The research mainly works with three variants of stem cells: Unipotent, multipotent and pluripotent. The unipotent stem cells have the ability to renew and regenerate, as do the multipotent and pluripotent stem cells. In addition, the multipotent stem cells have the ability to develop into a variety of different cell types, while the pluripotent ones can turn into any cell type in the human body. The unipotent stem cells, on the other hand, can only turn into one specific cell type. This makes pluripotent stem cells in particular quite unique.
Unfortunately, the pluripotent stem cells are only found in embryos in the very early stages of foetal development. When using these embryonic stem cells, scientists extract them from clusters of cells that are cultured 4-5 days after a test-tube fertilisation.
This is a challenge, because it is only possible to harvest tiny amounts of the coveted cells. In addition, working with embryos always raises a number of ethical questions and considerations.
Therefore, it is also particularly interesting that we are currently able to make stem cells of, for example, skin or blood cells. These are called induced pluripotent stem cells.
How do you make new stem cells?
You make them from skin or blood cells from a given patient by cleansing them of the very information that makes them skin or blood cells. You ‘reset’ them, so to speak. The best results are obtained with skin cells, which are taken from a biopsy of the patient’s skin.
The skin cells are reset by undergoing a form of genetic modification. By exposing the cells to a DNA circle (a so-called episomal vector) and subsequently exposing them to shocks, the cells absorb the vector and the genes from the vector are expressed in the cells. When that happens, they are reset, which takes about a month.
The use of a DNA circle is due to the fact that it leaves no traces in the new stem cells because it decomposes by itself shortly after the reset is initiated.
After the reset, the cells behave like pluripotent stem cells and are able to both renew, regenerate and, even more interestingly: Be ‘trained’ to be any type of cell in the human body.
What is the future potential of stem cells?
The potential is obviously massive. The continued research into stem cells will lead to new ground-breaking knowledge that will create the basis for treatments that would not otherwise be developed.
Stem cell technology allows us access to knowledge we could not get otherwise. Just as stem cell technology can be used for bone marrow transplantation, in the future it could be used to create more of the types of cells that a given patient may lack.
For example, clinical trials are already underway in which patients with Parkinson’s are cultured and infused with their own dopamine-producing nerve cells in the midbrain. It is precisely these cells that Parkinson’s patients lack, which is the cause of their tremors.
In the longer term, it will probably be possible to create and replace entire organs. However, this has long prospects, as organs are far more complex and consist of many different types of cells that must function and develop together.
Meet the researcher
Helle Bogetofte Barnkob is a medical doctor, PhD and Postdoc at the Department of Biochemistry and Molecular Biology, where she is part of the Martin Røssel Larsen Lab.