In a recent Q&A on the Stanford Initiative to Cure Hearing Loss blog, Robert Jackler, MD, chair of otolaryngology, discusses the projected timeline for Stanford to begin clinical trials of targeted stem cell therapies to treat hearing loss, as well as the challenges of coaxing primitive stem cells to mature into hearing cells.
On the topic of what types of hearing loss might possibly be treated with regenerative therapies, Jackler says:
We have the ambitious goal of curing virtually all forms of inner ear hearing loss. It is interesting that almost all forms of hearing loss ends up in the final common pathway which is loss of hair cells but with preservation of the hearing nerve and the overall structure inner ear.
In non-genetic hearing loss, where there are no fundamental flaws in the person's DNA effecting hearing, it will be possible to stimulate their own cells remaining within the inner ear to transform into hair cells.
In genetic loss, where the DNA is flawed, the challenge is greater because the correct DNA sequence is needed to re-create an inner ear - and we have a couple of choices. One is, genetic engineering to replace the incorrect DNA sequence through gene therapy. The second possibility is to implant cells with correct DNA, taken from the laboratory, into the inner ear. Finally we are excited about the possibility of directly replacing the gene product, the missing protein that the gene would have produced within the inner ear, by other means. We can fix diabetes by giving supplemental insulin. Imagine that we may be able to infuse within the inner ear molecules to provide what is missing or even engineer patient's own cells to produce an abundance of the missing material that is crucial for hearing.
Check back with the Stanford Initiative to Cure Hearing Loss blog for the second part of the Q&A.