Study Finds Cholesterol Fine-Tun...( Research in rodents shows amount in o...),Health

Research in rodents shows amount in outer hair cell membranes affects sound

FRIDAY, Dec. 14 (HealthDay News) -- The amount of cholesterol in the outer hair cell membranes of the inner ear can affect hearing, a new U.S. study concludes.

"We've known for a long time that cholesterol is lower in the outer hair cell membranes than in the other cells of the body. What we didn't know was the relationship it had to hearing," senior author Dr. William Brownell, a professor of otolaryngology at Baylor College of Medicine, said in a prepared statement.

In the study, published Dec. 14 in the Journal of Biological Chemistry, researchers manipulated cholesterol levels in the outer hair cells of the inner ears of mice and then measured the rodents' hearing ability.

"Depleting the cholesterol resulted in a hearing loss. Adding cholesterol initially increased hearing but later resulted in a hearing loss. So, you can change an animal's hearing just by adding or subtracting cholesterol," Brownell said.

The fine-tuning of cholesterol in these cells happens naturally during development and doesn't change much after birth. That's different than cholesterol levels in the blood, which can vary with eating habits.

"Will our hearing be affected if we continually eat greasy meals? Right now, we don't see a connection between the two," Brownell said. "The results of the study help us understand the cellular mechanisms for regulating hearing and give us another way to potentially help those with hearing loss."

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SOURCE: Baylor College of Medicine, news release, Dec. 14, 2007