WASHINGTON (Reuters) - Stem cells from tiny embryos can be used to restore lost hearing and vision in animals, researchers said Tuesday in what they believe is a first step toward helping people.
One team repaired hearing in guinea pigs using human bone marrow stem cells, while another grew functioning eyes in tadpoles using frog cells.

While there are no immediate uses for humans, they said their findings help describe some of the most basic biological processes underlying the development of hearing and sight, and may help in the development of the new field of regenera-tive medicine.

“These discoveries illustrate stem cell research’s continuing extraordinary potential to treat a wide range of deadly and disabling diseases that affect millions,” said Anand Swaroop, a stem cell researcher at the National Eye Institute, one of the National Institutes of Health.

Dr. Sujeong Jang of Chonnam National University in Gwang-ju, South Korea, and colleagues used mesenchymal stem cells from human bone marrow to restore hearing in guinea pigs whose hearing had been destroyed using chemicals.

They grew the stem cells into neuron-like cells in lab dishes and then transplanted them into the inner ears of the guinea pigs. Three months later, the animals appeared to have some hearing, Jang told a meeting of the Society for Neuroscience.

Jang said the goal was to regrow the tiny hair cells that are essential for mammals to hear, although she is not sure yet how the stem cells made this happen. They would eventually like to try something similar in humans, Jang told a news conference.

“When sensitive hair cells in the inner ear of humans and other mammals are killed -- by loud noise, autoimmune attack, toxic drugs, or aging -- the damage is permanent,” Jang said in a statement.
“Birds and reptiles are luckier. Their damaged hair cells apparently regenerate and can restore normal hearing.”