Melbourne: In what could help restore
hearing loss in humans, an Indian-origin scientist-led team
has shown for the first time that injecting stem cells from
nose into ears of mice with deafness improved their hearing.
Sonali Pandit and colleagues at Garvan Institute of
Medical Research in Australia have claimed that the research
has the potential to reverse or restore hearing during early
onset sensorineural hearing loss in people.
Sensorineural hearing loss occurs when hearing cells
in the cochlea lose their function. Frequently inherited, and
usually starting during infancy, the condition could slow a
child`s development and lead to speech and language problems.
The team found that stem cells appear to release
"factors", or chemical substances, that help preserve the
function of cochlear hearing cells, without the stem cells
becoming part of the tissue of the inner ear.
"We are exploring the potential of stem cells
to prevent or restore hearing loss in people. The mice we are
using have a very similar form of childhood deafness to their
human counterparts -- except, of course, that mouse years are
shorter. So a mouse will tend to lose their hearing within 3
months, where a person might take 8 years.
"We are encouraged by our initial findings, because
all the mice injected with stem cells showed improved hearing
in comparison with those given a sham injection. Roughly half
of the mice did very well indeed, although it is important to
note that hearing wasn`t completely restored to normal hearing
levels," team member Sharon Oleskevich said.
Adult human nasal stem cells were used in the study,
as they are plentiful, easy to obtain and unspecialised (so
have the ability to self-renew for long periods, as well as
differentiate into cells with a variety of functions).
Though it has taken five years to reach the current
stage of research, the scientists anticipate that it will take
a further decade at least for the findings to benefit people.
The findings have been published in the latest edition
of the `Stem Cells` journal.