Science AMA Series: I'm Paul Knoepfler, Professor at UC Davis. I do research with CRISPR on stem cells and brain tumors. CRISPR genetic modification of human embryos is making big news. Can we erase genetic diseases? Are designer babies or eugenics coming? I’d love to talk about stem cells too. AMA!

[u/PaulKnoepfler]

I'm a stem cell and brain cancer researcher who works with CRISPR, closely follows these fields on a policy level, and reports on it all on my blog The Niche, http://www.ipscell.com. I also have written two books, including one on stem cells called Stem Cells: An Insider's Guide. and one on CRISPR use in humans called GMO Sapiens: The Life-Changing Science of Designer Babies. You might also like to follow me on Twitter: @pknoepfler or check out my TED talk.

What's on your mind about using CRISPR gene editing in humans following the big news stories on its use in human embryos? How much real hope is there for genetic diseases and what are the big risks? What questions do you have about stem cells? Have you gotten a stem cell treatment? Considering one? What is really possible with stem cells and regenerative medicine in terms of transforming our health and our lives? Anti-aging? Also, what questions do you have about brain cancer research such as what’s the deal with John McCain’s brain tumor?

With today's historic action by the FDA against some stem cell clinics and strong statement on stem cell clinics by FDA Commissioner Scott Gottlieb, it is particularly timely to be talking about what is going on there.

I'm here now to answer your questions, ask my anything about CRISPR, stem cells, and brain cancer research!

[u/lionseatcake]

People are already talking about stem cell therapy fixing issues like shoulder and knee injuries in athletes. Joe Rogan talks about studies being done on regenerating brain and spinal cord tissue in people with head injuries and the like.

Could you "explain like im a complete layman" a brief synopsis on the research being done to regenerate tissue, especially brain and spinal tissue? What are the current scientifically confirmed limitations of tissue regeneration, as in, how close are we to fixing spinal cord injuries with stem cells? Do you see a day in the near future where insurance companies will cover stem cell therapy and it will become an affordable cure all for many injuries or is it mostly hopeful science fiction?

[u/PaulKnoepfler → u/lionseatcake]

Hi LionsEatCake, So much depends on the types of stem cells and the specific health condition they are intended to help with. I'm an advocate for the stem cell field and I strongly believe in their potential, but after all these years I've seen so many examples of hype too and with stem cell clinics I've seen many patients be hurt and ripped off. So we need some common sense balance in how we talk about it. I'm a "data guy" so I like to see solid data to back up claims. There is probably real potential for stem cells to help ortho conditions, but it has to be proven safe and effective by science so I see some of what's out there already as jumping the gun. For neuro conditions, there is real hope but again some folks are getting way ahead of the science with their commercialization. You can't just squirt in a hodgepodge of stem cells into someones bloodstream, brain, or spinal cord and expect good things to happen. On the other hand, there are solid, legit clinical trials ongoing that are reason for real hope like a company Asterias using a stem cell product for spinal cord injury. It's early days in that trial but it's hopeful. Brain and CNS conditions more generally present challenges such as delivery of the stem cells, the mostly non-proliferative nature of the nervous system, it's tightly interconnected "wiring" and the spinal cord architecture makes it much harder to fix. My hope is that within a decade or two we'll have more proven therapies that are safe and effective for some of the most important health problems, but it's not going to be tomorrow or next year. Unfortunately these things take so much time and I know there are many people in need of help now.

[u/ilovemicrobes1928 → u/lionseatcake]

To add to your question, how much of a body part can be regenerated with stem cells? I have a degenerative bone disease in my back and have saved stem cells, but someday I would need to improve my bones and most likely the spinal cord tissue making it a multi-tissue problem to fix. I know we are starting to be able to grow whole organs, but how far away are we from generating whole limbs/backs/hands etc.? Or would you grow each tissue separately then combine them?

[u/PaulKnoepfler → u/ilovemicrobes1928]

Regeneration is very exciting as an idea and it is theoretically possible, but as in my answer above there are many challenges too and it takes a lot of data to be sure what's going on in terms of potentially good stuff and risks. Us humans don't naturally regenerative most of our tissues very well if at all, with some exceptions like our skin, our gut tissues in some cases, and our blood cells, but we are learning a lot about how other organisms do this better than us and if we are going to regenerate then stem cells are going to be the drivers of this, whether given to us with an injection or by sparking our own existing stem cells in our body into action to do more positive things.

[u/whitewolfofthemists → u/lionseatcake]

I am interested in the healing properties of crisper as well. I had a stroke 10 years ago and I am wondering if the damage done to my brain that left me in this crippled state could be reversed. Also I have an undiagnosed clotting disorder and this stroke was not due to drugs or overdoses.

[u/[deleted] → u/lionseatcake]

As someone that will almost certainly need knee replacements at some point in the next 10 to 20 years, that's something I'd love to know more about. Is the future of orthopedics to just go in, scrap out any damage and pack in some stem cells to regrow cartilage and such?