“We found that the beta (oestrogen) receptor protects against hearing loss”in mice, said Barbara Canlon, a professor at the department of physiology and pharmacology at Karolinska Institutet in Stockholm.
Canlon, along with a handful of other Swedish and Australian researchers, carried out a large-scale study on mice, finding that one of two receptors the female sex hormone oestrogen binds itself to offers good protection against hearing loss in both males and females.
Their findings were published in the Journal of Clinical Investigation this week.
“The alpha (oestrogen) receptor has no affect on hearing loss (but) when you don’t have the beta receptor you get more of a hearing loss. We’re seeing the same effect in the males and the females,” Canlon told AFP.
While previous research has indicated that oestrogen affects the auditory system, showing for instance that women’s hearing can vary during their menstrual cycle or with menopause, the new study is the first to search for oestrogen receptors in the male ear and the first to pinpoint that it is the beta receptor that protects against hearing loss, Canlon said.
“The male (mice) have just as much oestrogen in the ear as the females,” she said.
The new research indicates that simple oestrogen replacement treatment would do little to protect against hearing loss, since “that’s going to affect both the alpha and the beta receptor, and it’s known that the alpha can have an inhibitory affect … its like ying and yang, so the end result will be zero,” Canlon said.
“The idea should be to give receptor-targeted treatment,” she said, pointing out that a number of beta-agonist drugs that stimulate the beta receptor are already on the market for treating illnesses like breast cancer.
Going forward the researchers hope to test their findings on aged humans, Canlon said, pointing out that 80 percent of people over 65 years of age develop hearing loss today.
The study could “really have potential for aged individuals,” she insisted.