Human Stem Cells Enable Deaf Gerbils to Hear

A new study reveals that human stem cells have varied but encouraging effects on restoring the hearing of gerbils with profound deafness.

Scientists have induced nerve damage to gerbils in order to test the effects of human stem cells on treating the resulting profound deafness. In the study published in the journal Nature, the results of the study on 18 gerbils showed that there is 46% recovery of hearing function. This was measured by way of electric signals in the animals’ brains.

Marcelo Rivolta from Britain’s University of Sheffield led the said research. He stated that in “a few years”, clinical trials for patients with hearing loss can be conducted.

Prior to injecting the gerbils with about 50 000 embryonic stem cells which have been treated with growth factors that would turn the stem cells into ear cells, the animals have been given a drug that would damage their auditory nerves making them deaf.

The effects of the treatment varied among the animals depending on the integration of the stem cells into the cochlea, the cavity in the inner ear which is spiral in shape.

Rivolta said, “What we have shown here is functional recovery using human stem cells, which is unique.”

According to Dr Craig Kasper, an audiologist check his homepage, “This procedure is still in its infancy and if proven safe and effective, it could really help deaf patients recover their ability to hear.”

Profound deafness is usually caused by damaged auditory nerves or loss of hair cells in the ear. Once these cells are damaged, there is no way of repairing them because they are only created in the womb. For that reason, embryonic stem cell therapy is a promising approach for treating permanent hearing loss.

There are dangers to the procedure as well because there is no certainty on how the recipient’s immune system will react to the injected stem cells. The researchers suggest that more studies be conducted to see how the stem cells will proliferate inside the body, something that is not seen on their 10-week study on gerbils. Scientists are still hopeful that in the future, this method can be used for treating patients which suffer from hearing loss.

The results of the study are encouraging. The researchers said that this proof of concept is definitely another step forward for the field of regenerative medicine. However, more studies are still needed to assess the long-term effects and safety of the therapy.