When smell cells fail they call in stem cell reserves

Apr 29, 2007

Hopkins researchers have identified a backup supply of stem cells that can repair the most severe damage to the nerves responsible for our sense of smell. These reservists normally lie around and do nothing, but when neighboring cells die, the scientists say, the stem cells jump into action. A report on the discovery will appear online next week in Nature Neuroscience.

“These stem cells act like the Army Reserves of our nose,” explains lead author Randall Reed, Ph.D., a professor of neuroscience at Johns Hopkins, “supporting a class of active-duty stem cells that help repair normal wear and tear. They don’t come in until things are really bad.”

The only nerve cells in the body to run directly from the brain to the outside world, olfactory cells are under constant assault from harsh chemicals that one might happen to catch a whiff of by accident, risking damage or death.

To figure out how the olfactory system repairs severely damaged nerve cells, Reed’s team exposed mouse olfactory nerves to a cloud of toxic methyl-bromide gas. Methyl bromide kills not only olfactory nerve cells but also neighboring, non-nerve cells in the nasal passage. Three weeks after chemical exposure, the researchers examined nasal cells to see which, if any, had grown back.

They discovered that the newly grown cells, both nerve and non-nerve, grew from HBCs-a population of cells not previously known for repair abilities. “We were stunned because HBCs normally don’t grow much or do anything,” says Reed. “And the most surprising thing is that HBCs can grow into both nerves and non-nerve cells; they do so by generating the other active type of nasal stem cell.”

The team then went back and looked at nerve repair under less damaging circumstances where only the olfactory nerve cells are killed. In this situation, the HBCs did nothing to repair the damaged cells; rather, they allowed the previously known stem cells to do all the repair work.

“The ability to smell is crucial for eating, mating and survival, and it’s important that the olfactory system be fully operational all the time,” explains Reed. “The HBCs act as a fail-safe to ensure continued function of the sense of smell.”

The discovery of these two distinct types of stem cells in one neural tissue is a first, says Reed, who is interested to see if other types of nerves in the body have similar repair mechanisms in play.

Source: Johns Hopkins Medical Institutions

Explore further: Secret of tetanus toxicity offers new way to treat motor neuron disease

add to favorites email to friend print save as pdf

Related Stories

Nail stem cells prove more versatile than press ons

Nov 21, 2014

There are plenty of body parts that don't grow back when you lose them. Nails are an exception, and a new study published in the Proceedings of the National Academy of Sciences (PNAS) reveals some of the r ...

Signaling molecule crucial to stem cell reprogramming

Nov 20, 2014

While investigating a rare genetic disorder, researchers at the University of California, San Diego School of Medicine have discovered that a ubiquitous signaling molecule is crucial to cellular reprogramming, a finding with ...

Patent issued for substance with medical benefits

Nov 04, 2014

A novel jelly-like substance developed by Kansas State University researchers was recently issued a U.S. patent. The substance may be used for biomedical applications, ranging from cell culture and drug delivery to repairing ...

Recommended for you

Stroke damage mechanism identified

22 hours ago

Researchers have discovered a mechanism linked to the brain damage often suffered by stroke victims—and are now searching for drugs to block it.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.