Washington: A study of the inner ears of chicken has given scientists at Washington University School of Medicine in St Louis new insights into the causes of human deafness and balance disorders.

The findings in the study, which will be published in the June 1 issue of the journal 'Human Molecular Genetics', provide new insights into the causes of deafness due to aging and the loss of essential cells. They also may help improve knowledge of how the inner ear develops.

The team measured the activity of more than 1,800 genes in sensory cells from two regions of the chicken inner ear: the cochlea, where sound is converted into nerve impulses, and the utricle, here balance is sensed. The investigators discovered more than 100 significant differences between the two regions.

The investigators used microarray technology to compare the activity of genes from the cochlea and utricle of chickens.

Microarrays allow the comparison of thousands of genes at one time to determine which genes are active. The microarrays used by lead investigator Michael Lovett, PhD, professor of genetics and of pediatrics and joint director of the division of human genetics and his colleagues showed that about 600 transcription-factor genes were active to some degree in both the chicken cochlea and utricle, and that about 40 were active in only one area.

A gene known as GATA3 may be involved in orienting sensory hair cells in the utricle, and the gene for beta amyloid, which is implicated in the death of neurons during Alzheimer's disease, is active in the chicken utricle reveals the study.

"Ultimately, we hope our work will lead to some form of therapy that will replace these cells when they are lost," says Lovett.

"We are born with only a few thousand sensory hair cells in each ear, and to maintain hearing and balance we have to keep them for our entire lives."

ANI