Yeah, that was the idea when Yamanaka found those four transcription factors. He didn’t even think of using them for rejuvenation. But later it turned out that rejuvenation and inducing stemness are two different processes. This makes sense because both processes are probably relatively complex and different enzymes are needed to get the job done. The Yamanaka factors trigger a cascade of events and once we understand the details of these processes it might be possible to control the rejuvenation part more reliably without risking turning differentiated cells into stem cells.
Ok, thanks again…I just had gotten the impression, from the MIT piece, that cell reprogramming by definition turns the cell into a stem cell, but in fact you pointed out that they’ve avoided doing this, so it seemed like they missed that very-important point. But I guess writing popular articles for new science can be a challenge to please all people 🙂
I’m mostly excited about Altos but I know popular science articles about Aging in particular are not normally looked-upon as helpful by those same scientists necessarily, for various reasons (like hype, or snake-oil, eternal dictators, sisyphus, etc).
Obviously, you can’t just turn specialized cells into stem cells in a living organism. If you turn a heart cell into a stem cell, it can no longer do its job in the heart and instead will cause cancer. However, Sinclair believes that it is possible to avoid this problem by working with a subset of the Yamanaka factors (without c-Myc) and by limiting the reprogramming time.
So I discussed the exact same problem. Sinclair and Belmonte proved that it can be done in vivo. But Ocampo is certainly right when he says that it is a risky procedure and it remains to be seen if this technology can be used in humans. So no contraction.
MIT: “One problem is that reprogramming doesn’t just make cells act younger but also changes their identity—for instance, turning a skin cell into a stem cell. That is what makes the technology too dangerous to try on people yet.”
hplus: “To start the rejuvenation process, doxycycline is given for a certain time. This activates the combination of the Yamanaka factors, which reverses the age of all cells without turning them into stem cells. After this, the treatment with doxycycline is discontinued.”
the issue is whether reprogramming changes the identity of cells–that seems to me to be the contradiction…
happy to hear your feedback, thank you much!
The point is that representing a physical property (intrinsic or systemic) is not enough to recreate this property physically. Representing a physical property in a book does not recreate this property. A book about black holes does not create black holes. Nobody who is reading a book about black holes has to fear to be swallowed by the book.
I am fine with different types of consciousness and an artificial brain that consists of physical neurons made of silicon might be conscious. We will know for sure once we have a theory of consciousness. However at this point we don’t have a clue how this theory could look like. It is futile to try to build something that we don’t understand at all.
What we already know for sure is that simulating neurons on a computer will not recreate physical neurons and therefore also not recreate consciousness just as simulating black holes on a computer does not recreate real, physical gravity. Nobody will be drawn into a computer by simulating black holes. Representations don’t have the physical powers of the things they represent. They only represent these physical powers.
at what point does a intrinsic property being accurately represented lose any meaning ? a artificial brain does not have to be conscious in the exact we are. it only has to be close enough that it is functionally the same. you cant honestly expect that them to have to be one to one. you don’t need a perfect water simulation. you just need a accurate one.