Ooh, I knew you couldn’t get enough of our squishier, yet rougher cousins and their nervous systems.
So, I told you about the amazing growth of a new nervous system. I told my dad about it over TG dinner, and he asked about potential in regeneration. I said: Whattayaknow, that’s what the other part of that same paper I worked on was about! The second paper looked at the process of neural tissue regeneration in echinoderms… specifically sea cucumbers!!!
So, how do these researchers think it is that echinoderms can regenerate, and why can’t we do the same? Basically, they have no myelin, and their glial cells are simple enough ththey are capable of dedifferentiating. The reason you can’t do this is because your ancestors apparently felt the need for their cells to be special. I mean, our glial cells are all highly specialized, and once a cell has been specialized, or set into an oligopotent progenitor cells, it cannot reverse back to pluripotency.
The sea cucumbers body induces neurodegeneration, killing cells within about 1.5 mm of the wound. Soon, glial cells near the margins dedifferentiate and grow new scaffolding providing a pathway for the growth of new axons. Ultimately, the damage is almost perfectly repaired. When we suffer neural damage, regeneration and migration of axons tend to be interrupted by glial scarring, especially by myelinating cells.
I don’t really know how to tie this one together, so I’ll give you this. My takeaway from this is that, if you wonder why you can’t completely repair damaged nerve tracts, and you feel jealous of the echinoderms who can, just remember that you have myelin and they don’t. Myelin is really good. It lets you think and process at an efficient speed.