There is hope for older people who lose their sense of smell, because stem cells can now be used to bring it back.
One in 20 people in Great Britain has lost or loses its sense of smell, often in old age or after viral infections.
According to the Association of Hearing Loss of America, around 48 million Americans – or one in five people – report some degree of hearing loss.
This can damage the quality of life, because odor is linked to taste, and can leave the food tasteless, causing many elderly people to lack appetite and risk malnutrition.
Scientists who try to reverse a permanently damaged sense of smell are now successful in mice.
There is hope for older people who lose their sense of smell, because stem cells can now be used to bring it back. Scientists trying to reverse a permanently damaged sense of smell are now successful in mice (stock image)
The solution came from a nasal spray that was administered to the animals and contained stem cells capable of becoming a cell in the body.
In the nasal cavity, they become nerve cells that absorb odors that come through the nostrils and transmit the signal to the brain, which identifies the aroma as pleasant or nasty.
When mice with no sense of smell were given the stem cells, days later exposed to a chemical odor that rustled like the urine of a larger predator, they tried to get rid of it and show that their sense of smell had returned.
Researchers, who confirmed that the mice could smell again by registering their nasal cell activity, hope that the same treatment could work for people in the future with the help of a tube to release the stem cells.
Dr. Bradley Goldstein, who led the study at the University of Miami, said: & # 39; This is the first model of odor loss that shows evidence of recovery using cell-based therapy.
& # 39; It is very important to understand that many questions must be worked out before considering this for a human patient. However, there is evidence that such an approach justifies further study. & # 39;
When mice without sense of smell were given stem cells, days later exposed to a chemical odor such as the urine of a larger predatory animal, they tried to get away from it, showing that their sense of smell had returned (stock image)
It was previously possible to restore the sense of smell in mice that used gene therapy.
This switches on a gene that is important for sniffing out odors that are lost in mice and humans as a result of certain diseases.
But stem cells hope to help elderly people who have lost their sense of smell by replacing nerve cells that experts say disappear as we age and are essential to detect odors.
To test the stem cell solution, the researchers eliminated the sense of smell of mice with the help of tamoxifen, the anticancer medicine.
This eliminates an important gene and removes small hairs in the nose of the mice, & # 39; cilia & # 39; called, they need to pick up odors.
They gave four mice a nasal spray with stem cells, which were administered under an anesthetic for 20 to 30 minutes. Another five mice received a dummy nasal spray that contained no cells.
Three of the mice that received the stem cells first indicated that they had regained their sense of smell when they received a chemical similar to the urine of an animal they would eat, such as a fox, and withdrew from fear.
However, it was very clear that the stem cells had worked when clusters of nerve cells appeared in the nose of the mice in the study, with newly grown & # 39; cilia & # 39; hairs to smell, and growing long wires that were connected to the brain to transmit odor signals.
The study also offers hope to people who have lost their sense of smell after illness, head injury and genetic disorders.
However, the authors warn that the same method, although proven to be safe and not causing cancer, does not work when connecting the human nose and brain.
Dr. Goldstein said: & # 39; We were a little surprised when we discovered that cells could hold fairly tightly with a simple nose drop. To be potentially useful in humans, the main obstacle would be to identify a source of cells that can do this, become the right neurons and connect to the brain in the right way.
& # 39; Either way, continuing to study the mechanisms in human cells needed for the production of functional olfactory neurons from progenitor cells will generally be important to move forward. & # 39;
The full findings of the study were published in the journal Stem cell reports.
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