It seems that in my not-that-long spanning memory, stem cells have played a major part in any politician’s re-election campaign. In the context of ‘How do you, MR(S) Politician, feel about the BABIES WE ARE KILLING TO HARVEST STEM CELLS?’. I honestly should’ve done this post during the height of the election this fall. But, I think you’ll still be interested and impressed with the information we have about stem cells and how stem cell research and therapies is moving away from the embryo-harvesting (aka ‘Baby Killing’ – not my words, the words of others!) and towards innovating and novel techniques.
So, what is a stem cell? Here are the basics:
A CELL is a unit of any organism. It makes up tissues and contains genetic material. All cells in the same organism contain the same genetic material. It just depends on how the genetic material is ‘expressed’ or used that determines what kind of tissue it becomes.
Got that? Try this on for size: A cell in your nose contains almost 20,000 genes. They make it look like a nose. Your eye looks very different from your nose. How many genes does it contain?
Answer: They BOTH contain 20,000 or so genes. These genes are expressed, or used, differently to make your nose look like a nose and your eye look like an eye. And the 20,000 genes? That is how many protein-encoding genes there are in the human genome. For a quick recap on how genes become proteins, check out this post.
Now you are completely, 100% sure what a cell is, and we can talk about what a stem cell is. While a cell may be part of a tissue and have the characteristics of that tissue (nose cells are nose cells, but they are not eye cells), a stem cell is an UNDIFFERENTIATED cell. UNDIFFERENTIATED is a fancy way of saying the cell has the capability to become any cell.
To make a person, or an ear of corn, or a cat, you have to start with stem cells. These cells are stimulated with hormones and other molecules to become noses, or a cornstalk, or a cat’s tail. In addition to being the basis for all organisms, these cells are important for a variety of therapies and research to make new therapies and learn more about certain types of cancers and immune diseases.
I won’t go into detail on all of the therapies that stem cells help with, but here is a laundry list of some of them:
Neurological injuries and disorders, including stroke, brain damage, and spinal cord injuries
Blindness and/or macular degeneration
Tissue redevelopment, such as kidney and liver
In fact, there are major clinical trials for a variety of stem cell therapies occurring right now. You should go check out this link for an updated list if you’re interested in stem cell therapies. Feel free to post back with questions or comments if you want some more info on this!
Up until now, stem cells seem pretty innocuous, even helpful. Maybe some of you are thinking ‘What’s the big deal? This can only help us!’. Most of the arguments about stem cells are about where they come from (i.e fetus or embryos), not what their potential uses are.
1) Embryos and aborted fetuses house the largest concentration of stem cells in one tissue. These ‘embryonic’ stem cells are largely undifferentiated, which makes sense: babies take 9 months to look like babies! Those cells are slowly becoming tissue-specific, but you have to start with a lot of non-specific cells to grow a whole baby! Once those cells undergo the specialization to become a specific tissue, they are no longer ‘stem cells’ and can’t be used for therapies.
2) There are stem cells in adults as well, but those are much less common.
3) Other organisms have stem cells – like the corn and cats I was talking about earlier – but while those can be used for some research to understand how stem cells work, they can’t usually be used for therapies. The human immune system is very, very sensitive, and implanting a cell that is from a mouse into a human usually results in your immune system attacking it and throwing it out.
The stem cells that are usually in the news are embryonic stem cells, as people are usually quite reactionary about ‘harvesting babies’ or even potential babies for research or therapy applications. One item that has been in the news is ‘cord blood’, which is the blood from the umbilical cord saved after your baby is born. This contains stem cells, and can be helpful in the case of later problems with growth, development, or injuries. There are a variety of cord blood registries, and sometimes people are able to use cord blood from one of their children to help themselves or another child.
If you’re still interested – and reading – maybe you might be interested in two fairly recent developments in science that may make all of this controversy regarding stem cells obsolete! One of them is a few years old, but in those few years, it has been replicated by a variety of labs, and has the potential to become the answer for how researchers can obtain more stem cells and develop more therapies. The other is brand-new, and featured in the November issue of Wired Magazine. This is a proof-of-principle study showing how non-embryonic stem cells can be harvested and applied for therapeutic purposes.
Here are some brief synopses of both:
1) In late 2007, a Japanese group reported the reprogramming of cells that build the structural framework for animal tissues into stem cells. These structural cells, called fibroblasts, are very common as your cells are constantly in flux and require the building of structural support into tissues. This group used human fibroblasts and applied four specific factors (like hormones, molecules, and other immune-like molecules) to reprogram them into stem-like cells. This is like when you get a computer from a friend and wipe the harddrive. It’s like a brand new computer for you, even though it’s already served its term as your friend’s computer.
Since this work was completed, it has been duplicated by other groups, and these cells are now being tested for research applications. There is some concern about using ‘reprogrammed’ cells for therapeutic applications, as no long term studies have been done to test how well these cells age and if they revert back to their original program. There is a nice review, written in mostly reasonable terms, to be found here.
2) Maybe you saw this cover on a recent issue of Wired?
Besides getting the attention of nerds and non-nerds alike, this article was about a new finding and potential therapy in stem cells.
In the Nov 2010 Wired Magazine, they interviewed the CEO's of a small biotechnology company in the San Diego area. They had recently discovered stem cells in the fat tissue of adults in small amounts. They were then able to remove fat, purify the stem cells, and implant them into the destroyed tissue of post-mammogram breast cancer survivors to provide regeneration therapy. It's like a therapeutic liposuction-breast augmentation in one fell swoop. Now, the implications here are HUGE. Potentially, if you or I get sick from a neurodegenerative disorder or have a traumatic injury, surgeons could remove our fat, purify out the stem cells, and treat our disorder with OUR OWN STEM CELLS. This prevents any potential immune attack, and could make the neccesity of embryonic stem cells obsolete. Besides, if American's wanted to donate all of our excess fat to science, I'm sure the outcome would be win-win from all sides ;).
Of course, this is just in development, but the proof-of-priinciple is there and the potential is huge. We'll have to keep an eye on this in the future.
If you want to read this article, look here.
Ok friends, it's time for me to go make some delicious food so I can once again masquerade as a food blogger. I would love your input on this post, and I hope you learned something and didn't feel overwhelmed. I'll take any advice or feedback into account when I tackle the next scientific post.