Research could help people with declining sense of smell

University of California, Berkeley, neuroscientists have discovered a genetic trigger that makes the nose renew its smell sensors, providing hope for new therapies for people who have lost their sense of smell due to trauma or old age.

The gene tells olfactory stem cells - the adult tissue stem cells in the nose - to mature into the sensory neurons that detect odours and relay that information to the brain.

''Anosmia - the absence of smell - is a vastly underappreciated public health problem in our aging population. Many people lose the will to eat, which can lead to malnutrition, because the ability to taste depends on our sense of smell, which often declines with age,'' said lead researcher and campus neuroscientist John Ngai.

''One reason may be that as a person ages, the olfactory stem cells age and are less able to replace mature cells, or maybe they are just depleted,'' he said. ''So, if we had a way to promote active stem cell self-renewal, we might be better able to replace these lost cells and maintain sensory function.''

Gary K Beauchamp, director of the Monell Chemical Senses Centre in Philadelphia, who was not a member of the research team, noted that the olfactory system stands out for its ability to regenerate following injury or certain diseases

''This new paper … presents an elegant analysis of some of the underlying genetic mechanisms regulating this regeneration,'' Beauchamp said. ''It also provides important insights that should eventually allow clinicians to enhance regeneration, induce it in cases where, for currently unknown reasons, olfactory loss appears permanent, or even prevent functional loss as a person ages.''