Stem Cell Research Shows Promise for Hearing

The Hearing Journal
June 1, 2005

A research team at Indiana University School of Medicine has reported successfully transforming stem cells taken from adult bone marrow into cells with many of the characteristics of the sensory nerve cells in the inner ear. That feat, reported in the March 29 issue of the Proceedings of the National Academy of Sciences, may help hasten the time when bone marrow cells from a profoundly deaf patient can be used to allow the person to hear.

The cells used in the research were marrow stromal cells, a type of stem cell from which fat, bone, and cartilage normally develops. Earlier research had shown that marrow stromal cells could be induced to transform into neuronal cells, but it was unclear if or how the cells could be further transformed into useful specialized neurons.

Team leader Eri Hashino, PhD, and her colleagues cultivated mouse marrow stromal cells with chemicals that caused them to take the shape and other characteristics of neurons. Then they exposed the cells to two molecules secreted from nearby tissues of the ear during embryonic development. The two molecules, known as Sonic hedgehog and retinoic acid, together caused the marrow stromal cells to further develop into cells with many of the characteristics of auditory neurons, such as the presence of specific genes and proteins.

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