General Question

Ltryptophan's avatar

Can they make the stem cells turn into the cells that make the stem cells?

Asked by Ltryptophan (10203points) May 20th, 2012

Instead of trying to find stem cells can they make the stem cells make new stem cells?

Maybe this is no longer an ethical question due to new advancements.

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8 Answers

XOIIO's avatar

Obviously, stem cells can make any, any cell in the human body. I’m pretty sure stem cells are in the body.

But, every cell has a limited number of times it can replicate or produce a new cell, so it’s a lot easier to get fresh ones from tasty abortion leftovers.

BhacSsylan's avatar

Yes, they can, and they do (the average life of a single stem cell is on the order of days, perhaps less, depending on cell type). However there are many problems with this. First of all, human cells (or most any cells derived from multicellular organisms) tend not to grow well on their own. As a result, it’s tricky to figure out how to maintain growth for extended periods after removal from the body. It took years to determine how to make cancer cells grow on their after taken from the body, and they’re rather notorious for being hard to kill. (See also: “The Immortal Life of Henrietta Lacks”)

The second problem is that cells do tend to break down over time. Stem cells lines, in the proper conditions, can be made ‘immortal’; that is, they will continue to grow and reproduce as long as the conditions are kept constant. However, time takes it’s toll. Cells may develop mutations, for instance. In the body, these can usually be fixed through various methods based on feedback mechanisms. On a petri dish, these mechanisms either don’t exist or aren’t as efficient (for instance, no immune system to police cell behavior), and as a result cells lines can become decrepit over time, taking on far too many mutations and either becoming cancerous, actually evolving away from the original human genome it was taken from (which has actually happened for some cancer cell lines, which is a fascinating development in and of itself), or simply dying.

So, overall, yes. It is certainly possible to make stem cells make more stem cells. However, this is certainly not the only problem. Cells are incredibly complex, and subject to a whole host of signals and behaviors we don’t yet fully understand (which is good, because otherwise I’d be out of a job). As a result, while we can make immortal cell lines, it is still necessary to sometimes create newer cell lines.

And, this is ignoring the fact that for things like potential treatments, stem cells with similar or identical genetics to the patient are key to stopping rejection, and that would be very hard to impossible to accomplish with some random cell line. However, I think I’d probably rambled enough for today.

[edit]Also also, in response to the title question (which is slightly different from the one in the details), the cells that make stem cells are stem cells, so that doesn’t really make sense. And if you go all the way back to the original embryonic stem cells, the cells that make those are the gametes, aka the egg and sperm. So that doesn’t really help.

lillycoyote's avatar

Apparently there are things called induced pluripotent stem cells that researches have been able to create by “genetically reprogramming” adult stem cells to behave kind of like embryonic stem cells. Maybe @BhacSsylan will return and comment on it further and explain if or how induced pluripotent stem cells might fit into the notion “making stem cells that turn into cells that make stem cells,” or if could be a possible avenue of research for “making stem cells that turn into cells that make stem cells” in the future, as per your question. He certainly knows more about it than I do and it is kind of an interesting question, even if I don’t know anything about it.

BhacSsylan's avatar

So, yes, iPSCs do exist and are very interesting, but from your link the main problem is “Although these cells meet the defining criteria for pluripotent stem cells, it is not known if iPSCs and embryonic stem cells differ in clinically significant ways.” Basically, while they look like embryonic stem cells, whether or not they are the same as embryonic cells are still an open question. And from other reports I’ve read, the general consensus is that they are potentially very useful (going back to my aside from above, if you can use a patient’s own cells, rejection chances plummet to near zero), however they simply are not the same as embryonic stem cells, and thus are not quite as good for several applications. They are a useful tool, but an additional tool to embryonic stem cells, not a replacement.

In more detail from what I recall, several problems are:
1) that while they can be re-differentiated into other cells, the reversion of the cellular machinery can cause aberrant behaviors in the cell that could cause issues. Cells do not usually revert like that (or at all, as far as we know), and so while some parts of the cell have reverted to a pluripotent state (that is, able to take any form), other parts may not, and so this may cause issues further along. Will a skin stem cell turned iPSC and re-implanted in bone marrow start producing skin cells somewhere down the line, resulting in a cyst or tumor?
2) immortalization and reversion of a cell that is ‘older’ can cause unforseen issues, because these cells may have things like cell damage or markers from previous differentiation that could disrupt the cell or cause it to become cancerous more easily. This is obviously an issue for any potential treatments.
and 3) we just don’t know yet. And that could be an issue. Again, this type of conversion usually does not happen, and we do not understand the underlying mechanisms enough to declare these as good as embryonic cells. There could be issues we haven’t foreseen yet. Again, they are a useful tool in many regards, but still not a replacement. That could possibly change in time, as iPSCs are a very promising line of study, but they’re not there yet.

Ltryptophan's avatar

@BhacSsylan wow, cool answers. Thanks. @lillycoyote nice follow up. I’m not pretending I understand the science here, but I’m sure it is a very important step to try to find a stem cell “factory”.

lillycoyote's avatar

@BhacSsylan Thanks for your comments. I started to read/glance over the Wikipedia entry on iPSCs and didn’t understand much of it; just enough to get the same impression I am getting from your answer: that there are a number of issues and problems with these types of cells but that the research is promising and has “an open future” as one the headings in the entry words it.

I don’t know much about the biology of stem cells but I try to follow some of the research. One of my favorite uncles had early onset Parkinson’s, which eventually killed him, after over 30 years of it; over thirty years of progressively diminishing capacity and ability to do anything and everything. It’s an absolutely devastating disease for anyone, but he was a very talented and accomplished cellist and his fine motor control was one of the first things to go and that was heartbreaking to him, of course, but also to everyone who knew and loved him. Anyone who has ever had the disease or watched someone they love destroyed by it, inch by inch, over the course of the years, knows how important stem cell research is or could end up being, and of course, not just for Parkinsons.

BhacSsylan's avatar

@Ltryptophan Not a problem! Glad I could help. Another thing I just thought of that slipped my mind is that while reserachers are searching for ways to make perfect iPSCs, they need something to compare them to, so that alone is another reason we still need embryonic stem cells. However, it is indeed an important step. Being able to create perfect iPSCs would be an amazing breakthrough for many reasons, not the least of which being the ability to sidestep ethical issues that have already resulted in stem cells research being at least a decade behind where it could be.

@lillycoyote Yes, there are many, many possible applications for many kinds of stem cells, all of which are very promising. It’s easy to get over-excited, and it’s always good to be wary of anything touted as a ‘miracle cure’, but stem cells do seem to have many potential uses for what were once intractable diseases. There was even a study recently that showed the promise of restoring sight to the blind (note: there were… issues… with the study, and it needs to be replicated. But it does show promise. Issues are not uncommon for such a preliminary study). And having lost a grandfather to Alzheimer’s, I certainly know what you mean.

lillycoyote's avatar

@BhacSsylan I’m sorry about your grandfather. It can be difficult to wait out that period, where you are ever hopeful, a period that is sometimes years, usually decades, between the beginning of “promising research” and the time, if and when, that research finally comes to fruition and starts producing viable, effective treatments that make a real difference in halting or maybe even reversing, or possibly even curing any one or another disease or disorder. It’s sometime two steps forward and one step back, in research, it seems: they see the promise, then they see the problems, and have to step back and try to find a way around the problems, if they can, or try to find a different road to go down, if they can’t.

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