I was recently asked for a moment in my life that blew me away. Well, other than childbirth. I remembered the day I first saw nerve cells under my microscope. These were the cells that, after several rounds of trial & fail, I had finally managed to obtain from my start-up embryonic stem cells. This was an absolute triumph and I was blown away.
Let’s start from the top. Embryonic stem cells are those precious groups of cells that appear during the very early stages of baby development in the mother’s womb. Fascinating as they are, these cells give rise to all cell types of our body. For example, at some point during development one of our embryonic stem cells hits a crossroad. One path goes towards blood cell types and another towards nervous system cell types. This tiny cell makes a choice and goes towards blood cell types. Then, another crossroad comes up, then another and another and finally, our cell becomes a red blood cell. Every time this cell goes down a path, it cannot go back. It starts to lose its ability to turn into other cell types, but it acquires a specific job.
How does this cell choose or knows where to go? Well, that’s a topic for another post. For now, I’ll stick with stem cells.
Scientists developed methods to mimic these developmental pathways of embryonic stem cells in laboratory conditions and they can generate various cell types of the human body. Why is this important? Because, we can use these methods to establish therapies for diseases where certain cell types need to be replaced. There is, however, much ethical concern regarding how human embryonic stem cells are obtained, and therefore, research and clinical trials using these cells are restricted (1).
Luckily, scientists also developed ways of using other stem cells for therapeutic purposes.
Long before I had my own baby, a friend was having hers and her doctor talked about the possibility of obtaining stem cells from the umbilical cord blood once the baby was born. They could store these cells for years and if necessary, use them for therapeutic purposes. She was asking for my advice on whether she should go for it. While embryonic stem cells generate all cell types of the body, umbilical cord stem cells generate only the cell types of blood. So, should her child need treatment for a blood disease in the future, they wouldn’t have to wait for a donor. This all sounded fantastic, but clinical applications are currently limited to few blood diseases and only to children. The latter is because the number of stem cells obtained from the cord is very low and we do not yet know how to increase their numbers safely. And the cost? In the UK, it varies between £1700 and £2500 (depending on the package and company) for 25 years of storage.
Then, there are the adult stem cells. As you can guess from the name, these stem cells are found in adults, which means no pre-birth decision-making is required. Yet, these cells are rare and, similar to cord stem cells, they cannot generate all cell types of the body, but only the cell types of their tissue of origin. Therefore, therapies rely on methods to detect, isolate and multiply the necessary adult stem cell types.
In that case, where are we with stem cell therapies?
Bone marrow transplantation is the most widely used stem cell therapy to treat diseases of the blood such as leukemia. In this treatment, bone marrow, which contains stem cells, from a healthy donor is used to restore healthy blood cells in the patient (2). Skin stem cells are grown in laboratory conditions to generate sheets of skin which are transplanted to the patient to treat areas with severe burns (3). Recently, a new therapy that uses adult eye stem cells to repair the damaged cornea has been approved by the EU (4). There are also ongoing research and clinical trials to use adult stem cells in diseases of the nervous system, heart, liver, bone and cartilage (2).
Now, you may ask why scientists still tackle with the controversial embryonic stem cells, while the other ones sound so promising. Well, to understand a disease and develop treatments, we need to learn more about normal development. Generation of various cell types from embryonic stem cells is a fantastic experimental system for that.
So, do I have a definite answer to the title question? No, I don’t because there is still much debate on whether storage of these cells proves useful (5). So, I can only explain the current state of research. I, for one, did not get cord stem cells stored when my baby was born. And, I trust he won’t need them.
Note: If you are curious about my cells, here are their pretty photos (6). On the left are embryonic stem cells and on the right are the nerve cells I generated from them. The cells are coloured because they were stained experimentally. These are mouse cells and no animals were involved in this study, just cells 🙂
If you would like to read more on stem cells:
The International Society for Stem Cell Research (ISSCR) offers great information on stem cells in A Closer Look at Stem Cells.
EuroStemCell is an EU-funded, fantastic network for resources, news and expert information on stem cells.
- de Wert, G. and Mummery, C., 2003. Human embryonic stem cells: research, ethics and policy. Human Reproduction, 18(4), pp.672-682. Pubmed: 12660256 (Open access)
- Stoltz J.F. et al., 2015. Stem cells and regenerative medicine: myth or reality of the 21st century. Stem Cells International, Aug 2015. Pubmed: 26300923 (Open access)
- Alonso, L. and Fuchs, E., 2003. Stem cells of the skin epithelium. PNAS, 100. Pubmed: 12913119 (Open access)
- Abbott, A. Behind the scenes of the world’s first commercial stem-cell therapy. Nature News Q&A, March 2015.
- Smellie, Alice. Thousands of parents pay to store their children’s umbilical cord blood (but scientists fear they are wasting their money). Daily Mail, 12 November 2011.
- Hekimoglu-Balkan et al., 2012. Intergenic Polycomb target sites are dynamically marked by non-coding transcription during lineage commitment. RNA Biology, 9(3), pp.314-325. Pubmed: 22336714 (Open access)