Human umbilical cord stem cells repair damage to the inner ear of mice
26 September 2008
An Italian research team has shown that damage to cells in the inner ear can be repaired by stem cells transplanted from a human umbilical cord.
The study, published in the journal Cell Transplantation, gives new hope that hearing loss due to cochlear damage can be reversed.
Roberto P. Revoltella and colleagues introduced stem cells, known as hematopoietic stem cells (HSC), into mice that had inner ear damage from noise, chemical toxicity, or both. Only the groups that received the HSC showed cochlear regeneration. HSC cells were traced, using a fluorescent marker, in order to see whether they had migrated into the cochlea. Migrating there would mean they were literally in a position to help regenerate damaged sensory cells.
"Our findings show dramatic repair of damage with surprisingly few human-derived cells having migrated to the cochlea," said Dr Revoltella. "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."
The results also show that less cochlear regeneration occurred in the group that was given HSC after noise damage than in the chemical toxicity group, which suggests that noise damage was the more severe. The greatest regenerative effects were found in mice given the most HSC. Interestingly, the team also found that cochlear tissue repair improved over time.
“This work highlights just how relevant this type of research is and provides new hopes for novel therapeutic approaches” said Dr Marcelo Rivolta of the University of Sheffield, who is working on a project supported by Deafness Research UK to restore hearing by generating replacements for damaged hair cells from human bone marrow and umbilical cord stem cells.
Commenting on the fact that the cells migrated to the ear having been introduced elsewhere in the body, Dr Rivolta added, “If it is proven that no unwanted side effects have taken place in the rest of the body, this will facilitate the treatment's development by not depending on a complicated and invasive ear surgery to deliver the cells.”
