According to an Italian research team publishing their findings in Cell Transplantation, hearing loss due to cochlear damage may be repaired by transplantation of human umbilical cord hematopoietic stem cells (HSC), since they show that a small number migrated to the damaged cochlea and repaired sensory hair cells and neurons.

The researchers used animal models in which permanent hearing loss had been induced by intense noise, chemical toxicity, or both. Cochlear regeneration was only observed in animal groups that received HSC transplants.

Sensitive tracing methods were used to determine if the transplanted cells were capable of migrating to the cochlea, and researchers evaluated whether the cells could contribute to regenerating neurons and sensory tissue in the cochlea.

"Our findings show dramatic repair of damage with surprisingly few human-derived cells having migrated to the cochlea," said Roberto P. Revoltella, MD, PhD, lead author of the study. "A fraction of circulating HSC fused with resident cells, generating hybrids, yet the administration of HSC appeared to be correlated with tissue regeneration and repair as the cochlea in non-transplanted mice remained seriously damaged."

Results also showed that cochlear regeneration was less in the transplanted group deafened by noise rather than chemicals, implying damage was more severe when induced by noise. Regenerative effects were greater in mice injected with a higher number of HSC. Researchers also found regeneration of cochlear tissues improved as time passed.

Revoltella says the results suggest the possibility of an "emerging strategy for inner ear rehabilitation….providing conditions for the resumption of deafened cochlea."

The study yields hope for a potential treatment for the repair of hearing impairments, particularly those arising from cochlear damage, says David Eve, PhD, University of South Florida Health, and the journal’s associate editor.

The journal’s editorial offices are at the Center of Excellence for Aging and Brain Repair, College of Medicine, the University of South Florida.

[Source: Science Daily]