A recent article published in Multiple Sclerosis News Today reported that newly identified immune cells prevented the death of injured nerve cells. A study finds that this particular immune cell group can promote repair to the nervous system.
It is a new entry in the never-ending struggle to move forward in treating amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS). This new discovery appears to offer promise and has been published in the Nature Immunology journal.
The central nervous system (CNS) is comprised of the spinal cord and the brain. The CNS is attacked by a person’s immune system causing inflammation and death of neurons.
People who have MS will generally see a progression in their disability because the CNS is not able to fully regenerate. It is for this reason, to be able to halt or even reverse the neurological decline, that new therapies are urgently needed.
The Earliest Study
One of the first studies leading to the discovery of the protective immune cells involved animal models with optic nerve injuries. Such injuries produce neuroinflammation and a response by immune cells.
Generally, the CNS is protected from peripheral (circulating) immune cells which are blocked by the blood-brain barrier (BBB). The intent is to protect the CNS from infectious invaders.
However, when the BBB is compromised, the circulating immune cells may make their way beyond it.
A fungal cell wall extract with neuroinflammatory properties called zymosan was found to prevent neural damage in animal models that sustained optic nerve injuries.
Notably, zymosan caused inflammation and protected retinal cells from dying. It also assisted in their regeneration. Retinal ganglion cells (neurons) are found near the retina’s inner surface.
Fast forward to the mouse model with an induced eye injury that was injected with zymosan. The researchers found an accumulation of a new form of white blood cells, called immature neutrophils, that cause immune reactions.
The neutrophils were found to accumulate in the vitreous fluid which is a gelatinous mass in the eye between the retina and the lens.
An additional response as a result of zymosan treatment was growth factor secretion that encourages wound healing and rapid cell growth.
The co-director at Ohio State’s Wexner Medical Center commented on zymosan’s ability to encourage regrowth of injured nerve fibers in the CNS which, he said, is unprecedented.
As an additional assessment of immature neutrophils efficacy, the researchers injected immature neutrophils into mice that had spinal cord and optic nerve injuries.
The growth of nerve cells confirmed that the neutrophils triggered neuronal regeneration in the CNS.
Dr. Andrew Sas, who is the study’s lead author, commented that the pro-regenerative neutrophil triggers spinal cord and optic nerve repair, confirming its relevance in the CNS.
A look to the future has researchers preparing to isolate and grow the cells in the lab. Now the cells can be injected directly into the patients with the goal of possibly preventing or slowing neurological deterioration.
The neutrophils are excellent candidates for multimodal therapy which involves multiple therapies to be delivered concurrently. The neutrophils have the potential to encourage regeneration after injury, rescue dying neurons, and prevent the inhibition of the growth of neurons.