Peripheral nerves can (they don't always, but often can) regenerate quite nicely, given certain circumstances, and their neuronal cell bodies are in the spinal cord. There are many different kinds of neurons but at least some of them can grow their axons after injury, following a "bridge", as you propose, of schwann cells.Originally Posted by Nowhere Man
Tom, you are right, it is open for debate, but when several scientist's studies (Kai Liu, Paul Lu, & others) have documented rivers of axons growing through animal injury sites, it is completely inaccurate to state that glial scars prevent regeneration. I'm confused why researchers are talking about cutting out the 'scar' when there is concrete evidence it is not necessary.
Seem Dr. Silvers peptide was able to get the axons to move in rat models. I believe that yes axons don't know where to go, but I believe with very intensive constant functional rehab , That the body can be rewired sort to speak. Dr. Young and a lot of the researchers in China have stated this is vital after any treatment that is why!
Don't See how gene therapy will help a chronic spinal cord injury I can understand it could benefit an acute spinal cord injury but not chronic after the damage has already been done and sat for a long time!
Clearly the doctors in this trial, and the clinical trial in Russia believe that the scar is an obstacle for regeneration!
Peripheral nerves are irrelevant. They are not the central nervous system (brain & spinal cord). Intrinsically, the brain & spinal cord do not regenerate. Any regrowth of spinal cord axons after treatment are extremely low percentage and very short distance. Oh, except umbilical cord blood cells + lithium! They regenerated from cervical down to cpg (very very far distance)...as believed by Dr. Young.
How many axons (all, a lot, a tiny fraction?) and how far? Images?
Jim, I don't necessarily disagree with those sentiments. However, you and Wise often say the scar is not a barrier to regeneration, yet I still haven't seen an alternative theory proposed. What is it that you/Wise think IS the barrier to regeneration after spinal cord injury?
I'll re-state the bolded text in my first post...the neuronal cell bodies of peripheral axons are in the spinal cord - they ARE in the central nervous system.
You said "adult neurons don't regenerate their axons". This is not always true. There are no neuronal cell bodies in the peripheral nervous system - only neuronal cell bodies in the CNS that have axons that branch out into the peripheral nervous system.
To say that the "brain and spinal cord" don't regenerate is oversimplifying it, since there are a multitude of different type of tissues, and an injury to the PNS creates a very different cellular environment than an injury to different parts of the CNS.
I don't think the lack of axonal regeneration after SCI can solely be explained by a lack of intrinsic growth capacity, since some axons (whose roots are in the spinal cord) clearly can regenerate.
Just because a peripheral motor neuron starts in the CNS does not make it equivalent to a motor neuron that starts in the brain! Peripheral nerves are different than brain / spinal cord nerves. Even different neurons solely inside the central nervous system have different genetic makeup. That's why only certain axon tracts regenerate with PTEN, while others don't.
I didn't say it was the sole reason. However, it is imo, a significant reason, and one that must be overcome.
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