How do “drugs” influence stem cells?
Here’s the straight dope.
Those of us in the trenches of the stem cell research field spend an inordinate amount of time talking about stem cell treatments (i.e. you inject stem cells into a person hoping for a medical benefit), and far too little time discussing endogenous stem cells.
Endogenous stem cells are those little guys that we all have already inside of us. They crawl around and do good things. Sometimes they do bad things like turn into cancer stem cells.
I think it is a reasonable prediction that how we live our lives greatly affects those natural stem cells and in turn our health. I’ve blogged before about how to try to protect those little, but oh so important cells.
Today’s topic is how drug use affects our stem cells.
Some of the more interesting research on this question is focused on the brain. While for decades we all “knew” that the adult brain had no stem cells, turns out we were wrong. The brain has a limited number of stem cells and they are doing their stemmy stuff up there in our craniums even if scientists don’t totally understand why they are there. Weirdly, at least part of the point of us adults (if you can call us scientists that) having stem cells in our brains seem to be related to olfaction.
In that famous anti-drug commercial “This is your brain…this is your brain on drugs…any questions?” the brain is represented by eggs and drugs fry them.
So do drugs fry stem cells in our brains?
The jury is still out in some cases, while in others its pretty clear that drugs do fry stem cells.
Arguably the most popular drug, booze, is often cited (and I’ve said this myself to the students that I teach) as an effective way to nuke your brain cells. But is that really true and what about affecting stem cells in the brain or elsewhere?
A Pubmed search for articles having these 3 key words in the title (stem cells ethanol) surprisingly only yielded 25 articles in total. What the heck? However, even from these 25 papers it’s pretty clear that stem cells are sensitive to ethanol and change their behavior in response. But there isn’t much evidence to speak of at least in that search suggesting that ethanol in physiological doses is toxic to adult stem cells.
One paper reported that MDMA (Ecstasy, Molly, X, 3,4-methylenedioxy-N-methylamphetamine) was not good for the rat brain, reducing stem cells and neurons.
In terms of embryonic stem cells (ESCs), MDMA was reported to be toxic to cardiac and neural cells made from ESCs.
Another study, however, found that MDMA slows proliferation of ESCs themselves, but actually promotes self-renewal (stem cells making more stem cells) without evident toxicity. At least in mice.
What’s up with pot and stem cells? Are high stem cells a good thing? Pubmed searches for THC and stem cells or marijuana and stem cells both yielded just under a couple dozen papers. The verdict? The high stem cells needed their media changed more often….but seriously, I would say these studies do not present a coherent case for how stem cells react to pot-related chemicals, but they sure do seem to react and some types of stem cells have cannabinoid receptors.
There are more than 100 articles that mention stem cells and opioids. Who knew? But actually most of these are focused on something else. Only 8 articles have these words in their titles. Again, the take home message is foggy, but there seem to be some kinds of effects including on stem cell differentiation.
There are many other drugs, recreational or not, that certainly influence stem cells as well.
Stem cells on stem cells.
Of course the ultimate irony here is that stem cells themselves, produced as treatments for various ailments, are considered drugs.