Big Think

Question: What are embryonic stem cells and why are they important

Loh:    Just as a quick background, embryonic stem cells are very amazing stem cells that can make all cells in the human body so that’s anything you can think of, like brain or skin or muscle.  This seems not interesting until you begin to consider how… if we can use stem cells to treat or cure human disease and human suffering.  And so if you think about it, lots of human diseases like diabetes or Parkinson’s Disease or… even aging, are because a certain kind of cell in the human body is lost.  So, for example, in diabetes, your pancreatic cells are lost and you can’t make any more insulin or in spinal cord injury, you lose your spinal cord cells and you can’t move anymore and this is very devastating.  So if human embryonic stem cells can make all cells in the human body then theoretically if you have spinal cord injury, we could take human embryonic stem cells, make a new infinite number of spinal cord cells and surgically put them back into your spinal cord and restore function of that and try to bring function back to your muscles.  And conceptually, we can extend this to any range of disease and I think that many people really look to stem cells as kind of a 2nd generation of medicine that right now we just give you drugs or pills or shots that basically are chemicals that try to restore some kind of biological function.  But with stem cells, what we’re talking about is that, if you are missing cells that we can just put them right back into you and that this kind of treatment called regenerative medicine, we think is very, very cool.

Question: When will regenerative therapy be widely available?

Loh: Realistically that this might even be a decade range and so I think while this is somewhat disappointing, many animal experiments with diseases like diabetes and Parkinson’s Disease that stem cells have remarkable abilities to help treat or even fully cure many kinds of diseases.  And recently, the FDA approved a huge… the first human embryonic stem cell based clinical trial and this is for spinal cord injury.

Question: What are the moral considerations relative to stem cell therapy?

Loh:    I think that while it… this has made it sound that human embryonic stem cell as very remarkable, as you probably know, there’s a lot of ethical and moral considerations about human embryonic stem cells and I think the fact that they are so clinically powerful but that they are some… that there’s a lot of considerations involved makes this very complicated and this is because as the word “human embryonic stem cell” implies that these stem cells are taking from a human embryo and so I think very unfortunately, oftentimes, when we take these human embryonic stem cells from the embryo, it leads to the collapse of the human embryo and so it can no longer develop. 

Question: What is reprogramming?

Loh:What I’m working on is an alternative around this so obviously, there’s a very big promise with human embryonic stem cells, how they can help cure disease and that I think that it’d be really awesome if you could find a new way to get them without having to destroy a human embryo.  And so recently, there’s a new technology called deprogramming that’s come up and so I told before that embryonic stem cells can make all cells of the body and so what we’re thinking of deprogramming is what if we can turn any cell into an embryonic stem cell and so the significance of this is that if we can take any old cell lying around and we can make it into an embryonic stem cell then we can basically make an infinite amount of human embryonic stem cell without ever touching a human embryo or harming a human life.  And I think that this is a big step to unlocking the widespread usage and ethical usage of human embryonic stem cells and that I know that at least some politicians and religious officials agree that this is a very big step.  And so this kind of what we call reprogramming, at Harvard, we’re very interested in how it works and so that’s part of what I do that comes in.  And so there are 3 genetic switches that if we turn on, we believe we can make many kinds of cells into human embryonic stem cells or human embryonic-like cells.  And that this kind of programming, if we want to bring it into the clinic, we have to think how this is going to work, how we can take cells from patients and turn them into stem cells.  And so there’s several ways to do this and very unfortunately the biggest way right now is to use viruses and that doesn’t make sense because if we’re using viruses to make stem cells and we eventually want to be able to use these stem cells to cure patients, there’s a logical catch right there.  And so there’s several other techniques but what our group is trying to investigate is whether or not we can use chemicals to turn cells into stem cells.  And so basically at Harvard, our group, what we do is we basically have lots of cells and we test thousands of chemicals on them, it’s called a chemical library.  And we see if any of these chemicals can turn these cells into human embryonic stem cells and I think that one day, the goal would be really that we could just take a cocktail of chemicals, dump it on any cell and turn it into an embryonic stem cell that can drive clinical therapies and can drive.