Sense Of Smell Restored With Gene Therapy
September 3, 2012

Cell Therapy Could Restore A Person’s Sense Of Smell

redOrbit Staff & Wire Reports - Your Universe Online

Individuals who were not born with an olfactory sense, or who lost the ability to smell due to a disease, could someday once again take in the sweet smells all around them courtesy of new research from the University of Michigan Medical School.

Dr. Jeffery Martens, an associate professor of pharmacology, and colleagues were, for the first time, able to cure the condition, known as congenital anosmia, and restore the sense of smell in mice using gene therapy, the university said in a September 2 statement. They discovered that the mice were lacking in a protein known as IFT88, which led to a lack of cilia -- the hair-shaped structures on the surface of a cell -- throughout the body.

"The researchers were able to insert normal IFT88 genes into the cells of the mice by giving them a common cold virus loaded with the normal DNA sequence, and allowing the virus to infect them and insert the DNA into the mouse's own cells," according to the statement. "They then monitored cilia growth, feeding habits, and well as signals within and between the nerve cells, called neurons, that are involved in the sense of smell."

The treatment lasted for three days, and just two weeks after its completion, the mice experienced a 60% increase in body weight, suggesting that they had been consuming more food than before the treatment. Furthermore, the researchers discovered that cell-level indicators suggested that neurons related to smelling were functioning correctly when the rodent subjects were exposed to the pungent chemical amyl acetate.

Their findings have been published online in the journal Nature Medicine.

"The researchers caution that it will take time for their work to affect human treatment, and that it will be most important for people who have lost their sense of smell due to a genetic disorder, rather than those who lose it due to aging, head trauma, or chronic sinus problems," the university said. "But their work paves the way for a better understanding of anosmia at the cellular level."

"Using gene therapy in a mouse model of cilia dysfunction, we were able to rescue and restore olfactory function, or sense of smell“¦ Essentially, we induced the neurons that transmit the sense of smell to regrow the cilia they'd lost," added Dr. Martens. "At the molecular level, function that had been absent was restored."

Martens added that the research could also be important in the treatment of other diseases caused by cilia dysfunction, including polycystic kidney disease, retinitis pigmentosa, and rare inherited disorders such as Alström syndrome and nephronopthisis. He also said that he and his team will continue to look for additional cilia-related genetic causes of anosmia, including head trauma and degenerative diseases.

The research was funded by four National Institutes of Health (NIH) divisions, and researchers from Duke University, the Baylor College of Medicine, the University of Alabama-Birmingham, the NIH Intramural Sequencing Center, the Université Paris Descartes; St. James's University Hospital in the UK, and University College London were also credited as authors on the study.