Stem Cell Research Provides Sound In Vitro For Deafness

One in 1,000 children suffer from deafness or hearing loss, especially considering that it is the most common sense affected by congenital disease. Scientists found that deafness at birth is often caused by specific gene mutations, which in some populations are responsible for as many as half the instances of congenital hearing loss.

However, a collaboration of researchers was able to demonstrate differentiation from these stem cells into specialized cells that are said to be the most important target for the treatment of hereditary deafness, as noted in the findings published in Stem Cell Reports.

Stem cells, which are a type of cell that can change into another, more specialized one through the differentiation process, are usually present in embryos and as repair cells. However, embryonic stem cells have the ability to differentiate into several different types of cells and can be induced in adults by reprogramming non-reproductive cells.

Researcher Kazusaku Kamiya and his team were able to produce supplies of the gene responsible for deafness -- known as Gap Junction Beta 2 (GJB2) -- to use for therapeutic studies. In their report, the researchers stated that cochlear cells are not accessible for biopsy or direct drug administration, due to their limitations anatomically.

However, they added, "ES/iPS [embryo stem/induced pluripotent stem] cells are an important tool for studying the molecular mechanisms underlying inner-ear pathology as well as for generating cells for replacement therapies."

To understand how this works, we have to understand the ear. As PR Works noted, there are three main parts of the ear: the outer, middle and inner. The ear canal in the outer ear channels the sound vibrations from the outside, to the ear drum in the middle ear. This same part contains three bones that help transfer vibrations of the eardrum to the cochlea, a spiral cavity in the inner ear that is filled with fluid. The movement of the fluid of the cochlea responds to the vibration, which is detected thousands of hair cells that convert the motion into electrical signals -- and we sense them as sound.

The Gap Junction cells facilitate the formation of intercellular communication networks in the development of the cochlea -- and the researchers were able to differentiate the deficiencies as demonstrated by mice in the formation of the gap junction plaques.