Smell of Success: Gene Therapy Restores Smell in Mice

In a first, scientists have reinstated the sense of smell among mice using gene therapy.

A team of international researchers led by the University of Michigan Medical School have cured the mice affected with congenital anosmia, a condition wherein the individual suffers a lifelong issue of their inability to smell.

They tested the mice with a genetic disorder which affected the protein known as IFT88 gene. The mutation in the gene, in turn, had problems in producing cilia. Cilia are hair-like structures that help to move the cells around.

Mice with lack of cilia can be poor feeders and they can also face a major risk of death. Cilia are also present in most cells of the human body. The mutation caused trouble in producing cilia and hence the mice lost their ability to smell.

Experts used gene therapy, wherein they created a common cold virus with the normal DNA sequence of the IFT88 gene and inserted them into the cells of the mouse through the nose. They performed the experiment for three continuous days, according to a report from University of Michigan Health System.

They observed the cilia growth of a mouse along with other factors such as their feeding habits, their size and the signals to the nerve cells that play a part in the sense of smell. They noticed a 60 percent increase in the size of the mice 14 days after the completion of the three-day treatment. The increase in size showed that the mice were feeding well.

Experts also noticed that the nerve cells also known as neurons signaled when the mouse was exposed to a strong-smelling chemical called as the banana oil. This way the researchers were able to restore the sense of smell in the mouse.

"Using gene therapy in a mouse model of cilia dysfunction, we were able to rescue and restore olfactory function, or sense of smell," senior author Jeffrey Martens, an associate professor of pharmacology at U-M, said in a statement from the university.

"Essentially, we induced the neurons that transmit the sense of smell to regrow the cilia they'd lost," he said.

Experts suggest that the study can help in the future treatments of congenital anosmia affected in humans.

The findings of the study are published in the journal Nature Medicine.