On June 3, 2025, an important study was published which sheds light on the role of previously thought dormant stem cells in our sense of smell. Researchers at Tufts University School of Medicine and the Graduate School of Biomedical Sciences (GSBS) conducted a groundbreaking study, revealing that certain stem cells play a substantial role in maintaining olfactory function, possibly offering insights into why some individuals experience a decline in their sense of smell.
The Marvels of Olfactory Regeneration
Unlike the central nervous system, the sensory neurons located in the nasal cavity have an extraordinary capability to regenerate throughout an individual’s life. This regenerative prowess, however, can be impeded by various factors such as:
- Viral Infections: Conditions like COVID-19 are known to affect olfactory functions.
- Toxins: Exposure to environmental toxins can damage sensory neurons.
- Aging: As individuals age, the regenerative ability of these neurons decreases, leading to potential loss of smell.
Research Insights
The research team devised a novel, easy-to-create, three-dimensional tissue model, known as an olfactory organoid, to study these phenomena. Findings from the study, recently published in Cell Reports Methods, highlighted the roles of two key types of stem cells in the nose:
- Horizontal Basal Cells (HBCs)
- Globose Basal Cells (GBCs)
These stem cells were shown to communicate and support the production of new smell-sensing neurons. Brian Lin, senior author of the study, commented:
“Our research suggests that these two stem cells may be interdependent... One type that we thought was largely dormant—HBCs—may actually play a crucial role in supporting the production of new neurons and the repair of damaged tissue.”
Key Findings
Among the noteworthy findings of the study are:
| Cell Type | Function | Significance |
|---|---|---|
| HBCs | Support new olfactory neuron generation | Thought to be dormant but are essential for tissue repair |
| GBCs | Provide necessary signals for neurogenesis | Decline in population contributes to reduced olfactory function in aging |
The Model's Impact
Lead author Juliana Gutschow Gameiro worked to develop this organoid model, which allows researchers with limited resources to conduct studies on olfactory regeneration processes. Lin noted:
“We wanted to develop an easy-to-use model so that non-stem cell biologists could better understand how olfactory neurons regenerate.”
Path to Human Organoids
The ultimate ambition of this research is to adapt the mouse model to create a human olfactory organoid, facilitating drug screening for conditions associated with diminished olfactory senses:
- COVID-19: Associated with temporary or permanent loss of smell.
- Neurological Disorders: Such as Parkinson's disease which may affect olfactory function.
Lin expressed the challenges faced:
“It's challenging to get pure olfactory tissue from humans; the process is complicated and requires careful separation of stem cells.”
Conclusion and Future Directions
This research paves the way for potential advancements in understanding and treating conditions related to olfactory dysfunction. Future studies will aim to:
- Enhance techniques for separating human olfactory stem cells.
- Investigate rejuvenating methods for decreasing populations of GBCs.
- Extend the applicability of olfactory organoids to other related fields.
The accessibility of this new model is likely to stimulate further studies across various scientific disciplines, expanding knowledge on olfactory regeneration and aging.
Additional Information
For further reading, please refer to the original study: Quiescent horizontal basal stem cells act as a niche for olfactory neurogenesis in a mouse 3D organoid model - Cell Reports Methods, 2025.
Citation: Stem cells thought to be dormant may offer clues to why sense of smell is lost or declines (2025, June 3) retrieved from Science X.
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