Stem Cell Research And Hair Regeneration Techniques As A Cure For Tinnitus - Update

There is currently a lot of research into ways of ‘regenerating’ the auditory hair cells as a cure for Tinnitus and a lot of progress has been made over the last few years in the area of stem cell research and hair cell regeneration.

Hair cells important

Hair cells are important because they are the sound receptors of the hearing organ called the cochlea. When the cochlear hair cells die this is usually acknowledged as the main cause of sensorineural deafness.

Now naturally your hair cells die as you get older and they can also be damaged or even killed by exposure to loud noises, ototoxic agents such as chemicals and prescription drugs.

At this point its impossible to regenerate hair cells so its important to keep them healthy as long as you can. Save your ears - Some Tips

Birds and Tinnitus Cures - What is the Connection?

In birds their lost hair cells are replaced by new hair cells and the outcome is virtually complete cellular and functional recovery of their organ. However unfortunately in mammals hair cells do not regenerate and researchers are now attempting to discover how hair regeneration such as that which appears in birds might be achieved in mammals (humans) and help with a cure for deafness and tinnitus.

As the researchers gain a much better understanding of how the hair cells are initially generated at the development stage of the human embryo they have identified certain genes that can trigger precursor cells/

These are the cells from which all other cells are formed in the human body. This helps to differentiate the hair cells and the researchers are looking at the possibility of utilizing these genes in ‘gene therapy’ which can then create non-sensory cells in the tissue of the cochlea. This will assist to create new hair cells to replace the original lost hair cell group.

Transplanting stem cells into the cochlea.

Because stem cells are cells that can divide they can also renew themselves and they are capable of transforming into specific types of specialised cells.

Already researchers have located small group of stem cells in the vestibular organs of the ears in mammals as well as working out how to encourage these stem cells to transform themselves into hair cells in a culture dish under lab conditons.

To date researchers have only been working with mice but this leads the way open to begin working with human stem cells and the possibility of transplanting cultured stem cells into the cochlea where they will regenerate and assist in healing deafness and potentially removing tinnitus.

Dr Rivolta told BBC News Online. “We’re talking very early stages, but this sort of treatment could eventually help people who’ve lost their hearing as a result of degeneration of the cochlear, those who’ve lost hair cells because of loud noise or drug treatments, and people with certain genetic conditions.”

He was addressing a one-day conference in London organised by the Royal National Institute for Deaf People (RNID) which brought together scientists from around the world working on treatments for hearing loss.

Dr Rivolta said that his research had shown that stem cells from sensory nerves could be regrown in a damaged part of the ear which, potentially, could restore a person’s hearing. “What we are trying to do in the lab is to use chemicals to tell a cell to do a particular task - in other words to mimic what normally happens in the embryo.”

Marcelo Rivolta says early results are promising. Dr Rivolta estimates that it will be between 10 and 15 years before such treatment could be made available, but he says the early indications are “exciting”.

A treatment that could be available much sooner was explained by Jonathan Kil of Sound Pharmaceuticals - a company which, he says, is the first in the world to try to develop drugs to treat hearing loss. Sound Pharmaceuticals has already registered one of its products - code named SPI 1005 - with the Food and Drugs Administration and has taken out a patent on it. If clinical trials with the US army are successful, SPI 1005 could be used to treat people whose hearing has been damaged as a result of exposure to excessive noise.

Eighty soldiers involved in live weapons training with handheld rifles are taking part in the first trials. “Even with state of the art protective devices a significant proportion will develop both temporary and permanent hearing loss as well as tinnitus,” said Mr Kil. “Having the drug on board before, during and after rifle training could prevent and treat the hearing loss associated with the occupational exposure.”

The company hopes that a product could be on the market in about three years from now. It estimates that in the US alone, 30m people are exposed to noise that could damage their hearing every day.

A Danish researcher told the conference of his company’s efforts to develop a drug to counteract tinnitus - noises which are heard but which have no external sound source.

“Tinnitus is a lot like the pain experienced by people who have had a limb amputated,” said Mads Korsgaard, from a company called NeuroSearch. He says that neuronal circuits in the brain somehow become altered which creates a perception of sound.

The company hopes that by identifying and then stimulating the parts of the brain that cause tinnitus, its effects will be dampened if not alleviated entirely. But a chemical cure for tinnitus is still a long way off - it will be at least a decade before NeuroSearch’s work will bear fruit. Source BBC News Online.