Researchers discover immune cells help clear damage, rebuild nerves after injury

While people usually identify immune cells in preventing bacteria, a team of scientists from the Case Western Reserve University School of Medicine showed that these cells could do so much more than keeping you from getting sick. According to their study, immune cells called neutrophils assist in clearing nerve debris after sustaining an injury.

Researchers are now looking at other benefits that neutrophils have aside from clearing nerve debris after the results of the study. They have previously believed that these cells, while one of the most common, are only known to trap harmful microorganisms and are generally not associated with nerve damage, like those from conditions like diabetes or trauma – as this was understood to be done by another cell altogether. This other immune cell type, macrophages, was what scientists believed to be responsible for dealing with nerve debris by engulfing it and breaking it down.

In an in vivo study, mice with lacking receptors for macrophages were observed. The researchers expected that the lack of receptor would mean the immune cells will be unable to clear the nerve debris that was sustained from injury. However, the clearing process remained the same as with a control group, indicating that another immune cell type is clearing away the nerve debris.

“We came up with a list of potential cellular candidates that could be compensating for the loss of these specific macrophages and used several different tests to determine which cells were clearing away the nerve debris after injury,” according to research fellow Jane Lindborg. In order to determine the cell that was responsible for it, the team looked at various immune cells at the injury sites, as well as the molecules before determining that neutrophil was the key. “Though it turns out that several different cells pick up the slack in the absence of macrophages, it was the neutrophil that emerged as a major contributor to debris removal. We also discovered that when we depleted neutrophils, nerve debris clearance was significantly halted in both normal mice and mice lacking a major population of macrophages.” Without neutrophils, nerve cells could not properly clear debris.

The study’s findings open up new possibilities in future treatments of nerve cells that are damaged by neurodegenerative diseases. The research team stated that the process of clearing out nerve debris is critical in nerve regeneration. The results also indicate that specifically targeting neutrophils may also enhance clean-up and promote its repair. They also stated that additional studies would be made to determine how neutrophils can be used with other cells to promote nerve regeneration further.

Recognizing nerve damage

In the U.S. alone, 20 million suffer from peripheral nerve damage, also known as neuropathy. While diabetes and other conditions are top of this list, causes like repetitive motion, aging, vitamin deficiency, and exposure to toxins (like alcohol) are also some of the ways that a person can damage his nerves. (Related: Omega-3 foods essential to treat nerve damage after traumatic injury.)

Here are some ways to recognize nerve damage early:

• You experience numbness, tingling, or burning. While this may be common for nerve compression (such as when a person is sleeping), a continuous pins-and-needles feeling is one to look out for.
• You find it difficult or impossible to move a part of your body. Damage to the motor nerves causes weakness or paralysis. Additionally, these may also be signs of more serious conditions.
• A part of your leg has a running pain. A constant sharp pain from your lower back to your leg may mean that your nerve has been compressed.
• You’re clumsier than usual. An occasional stumble or fall may not mean anything, but if you find yourself stumbling or falling regularly, then it may be a sign of nerve damage.

Sources include:

CaseMed.case.edu

Prevention.com