Question: What limits are there to stem cells, is there anything they'll never be able to do?

Christopher Todd answered on 13 May 2021:

Wow, big and very interesting question and I could probably talk about it for hours.

Firstly stem cells are not all equal, some have already begun to change and are then locked into becoming one type of cell, like a blood stem cell in your bone marrow, which can only become blood cells. There are limits as to what we can do with these.

But stem cells that are similar to those we find in the embryo, those can truly become any cell type in the body. We could in theory use these cells to grow any cell type we want and make entire organs from scratch, which we could then transplant into patients to help improve or save their lives.

Problem is we don’t know yet all the complex conditions we need to grow the cells under to encourage their development into all the cell types. We are beginning to learn though. For example we now understand that to grow heart muscle cells, we need to physically stretch the cells back and forth to mimic the heart beating.

There are also problems were some organs are more complex than others, requiring complicated structures and combinations of cell types which will need a lot of work to figure out. Science is beginning with easy organs like the bladder which just requires a couple of cell types.

We are also beginning to understand how to “program” stem cells by changing their DNA to do things that even normal cells couldn’t do.

So really, stem cells are pretty limitless as to what we can do.