A study published in the "Stem Cell Report" found that a stem cell therapy implanted in the nose can restore the sense of smell in mice that have lost their sense of smell. This indicates that this type of therapy may have broad application prospects in the treatment of a series of clinical conditions related to loss of smell.
"This is the first successful use of cell therapy to restore the sense of smell in anosmotic mice," said Bradley Goldstein, a senior researcher at the Miller School of Medicine at the University of Miami in the United States. "Of course, many problems have to be solved before it can be used in humans. But for now. The results really show that this therapy is worthy of further research."
Relevant statistics show that 12% of Americans have suffered from olfactory damage. The causes of olfactory damage are various, including aging, sequelae of viral infection, head trauma, and genetic diseases that affect the function of olfactory neurons. .
However, olfactory damage is generally permanent, and there are few corresponding treatments. A series of recent mouse studies have shown that viral vector gene therapy may help restore olfactory function, but this therapy usually needs to be "tailored" according to the different conditions of the patient; cell replacement therapy is expected to be widely used for many reasons Olfactory damage.
“There is evidence that a lot of acquired loss of smell is caused by damaged or missing neurons that cannot be replaced normally. Therefore, we want to try cell-based treatment to see if the idea of replacing olfactory neurons is feasible.” Goldstein said.
In order to test this idea, Goldstein and his team constructed a mouse model of loss of smell due to defective olfactory neurons. This mouse lacks the Ift88 gene, and its olfactory neuron cells lack "ciliary hair"—the hair-like structure needed to sense odors, so they cannot smell. Subsequently, the researchers used nasal drops to place spherical basal cells (a type of stem cells that can continue to replenish aging or damaged olfactory neurons) into the nasal cavity of mice.
After transplantation, adult stem cells can differentiate in the olfactory epithelium in the nasal cavity and produce mature olfactory neurons with normal functions. These new olfactory neurons can send neural projections or axons to the olfactory bulb in the brain, allowing the mice to restore their sense of smell. In subsequent behavioral tests, the Ift88 gene-deficient mice that received stem cell therapy responded normally to the offensive odor, while the untreated mice did not respond. In addition, no tumors were detected in the mice during the study period, indicating that the therapy may be safer.
Goldstein said, “If this therapy is to be further applied to humans, the main difficulty at present is to determine which types of cells can be transplanted and differentiated into olfactory neurons, and can establish the correct connection with the olfactory bulb of the brain; it is also necessary to figure out that in addition to this in animal models In addition to the severe damage to the sense of smell, what other conditions can this therapy apply to?"
In future research, Goldstein and his team hope to more accurately find out the various specific causes of common human acquired olfactory disorders.