We know that stem cell treatments can be highly effective at treating back pain (including lower back pain), urinary stress disorder, and knee pain. Stem cell injections are a regenerative therapy that works and is highly effective for certain individuals. But could stem cells be used to even restore a sense of smell?
Stem cells as regenerative therapy have certainly worked in mice. In mice whose sense of smell was disabled, stem cell injections into the nose were able to restore olfaction, researchers announced last year in Stem Cell Reports.
“We were a bit surprised to find that cells could engraft fairly robustly with a simple nose drop delivery,” senior author Bradley Goldstein of the University of Miami Miller School of Medicine says in a press release. “To be potentially useful in humans, the main hurdle would be to identify a source of cells capable of engrafting, differentiating into olfactory neurons, and properly connecting to the olfactory bulbs of the brain. Further, one would need to define what clinical situations might be appropriate, rather than the animal model of acute olfactory injury.”
Independently Verified: Exciting Possibilities
Olfaction sense was restored in mice via stem cell therapy independently by a number of researchers. But scientists had difficulty determining whether the regained function was a result of the transplant or from simulation from endogenous repair that led to a loss of the ability to smell. To better identify the cause, researchers developed a mouse with resident globose basal cells made by nonfunctional neurons. This way, any smell restoration would be due to the newly introduced cells.
“The team developed the stem cell transplant by engineering mice that produce easily traceable green fluorescent cells. The researchers then harvested glowing green globose basal cells (as identified by the presence of a receptor called c-kit) and delivered them into the noses of the genetically engineered, smell-impaired mice. Four weeks later, the team observed the green cells in the nasal epithelium, with axons working their way into the olfactory bulb.
“Behaviorally, the mice appeared to have a functioning sense of smell after the stem cell treatment. Unlike untreated animals, they avoided an area of an enclosure that had a bad smell to normal mice.”
More Studies Needed Before Human Treatments
Before stem cells could be used to restore the sense of smell in humans, more experiments will be necessary.
“The challenge is going to be trying to [engraft analogous cells] in humans in a way . . . that [would] not make things worse,” says James Schwob, an olfactory researcher at Tufts University who has collaborated with Goldstein but was not involved in the latest study, in an interview with Gizmodo. “One strategy for the future would be to try to figure out a way to get the transplants to engraft without having to damage the [tissue] first.”
Significant Findings, Promising Possibilities
Nevertheless, the potential implications for those who have lost olfaction is highly significant.
“I’ve had patients very eloquently talk about how much they miss being able to detect odors,” Goldstein told Gizmodo. “Many of them are really, really bothered by it.
“People tend to see wear and tear, or a failure to maintain a healthy olfactory neuron population in [their] nose,” Goldstein continued in his conversation with Gizmodo. “These are pretty vulnerable neurons that are exposed to the outside world. Things can damage them and even though they tend to regenerate pretty well, things can wear out.”
“[Previous research] found that if even a fairly small percentage of all olfactory neurons are restored, that seems to result in clinically significant function in other animal models,” Goldstein continued in his conversation with Gizmodo. “So we think that even a modest restoration of that neuron population may be significant.”
Stem cell therapy is a highly effective treatment that works for a growing number of conditions — and we are only at the cusp of being able to understand its potential. We’ve seen patients gain significant restoration via stem cell therapy for back pain, knee pain, and neck pain. If you would be interested in learning how stem cell treatments may help your pain management, contact our offices in Cincinnati or New York.