Study Investigates Protein Levels in Nose Epithelial Cells Related to Coronavirus Entry

Background on Coronavirus Spread

A recent study focused on the elevated levels of a protein found in nasal epithelial cells, which serve as the entry point for the coronavirus. As the world continues to grapple with the extensive spread of this life-threatening virus, researchers are diligently working to decipher how it infiltrates the human body. Currently, it is understood that the coronavirus enters cells via the angiotensin-converting enzyme 2 receptors, commonly known as ACE2. The localization of this protein is crucial for understanding the virus’s transmission.

Research Findings on ACE2 Receptors

A survey conducted in Europe revealed that approximately 85% of respondents experienced disturbances in their sense of smell. This prompted researchers from Johns Hopkins Medicine to delve into the presence of ACE2 receptors in human nasal and tracheal samples. The study involved four healthy individuals and 19 patients suffering from an inflammatory nasal condition, along with tissue samples from seven patients who had undergone tracheal surgery. The findings were summarized in a publication by the European Respiratory Journal.

Prevalence of ACE2 in Nasal Cells

The researchers found that ACE2 receptors were significantly more abundant—up to 700 times—within the sustentacular cells in the upper nasal region compared to the epithelium of other areas of the nose and the trachea leading to the lungs. Sustentacular cells play a supportive role for the odor-sensing neurons in the nasal epithelium. These observations may provide insights into the mechanisms behind the loss of smell often reported by coronavirus patients, even when other symptoms are absent. The researchers emphasized that this part of the nose is particularly vulnerable to infection, urging individuals to wear masks properly.

Potential Neurological Implications

There is also concern that the coronavirus may access the brain through the nasal pathway, potentially resulting in neurological symptoms in infected patients. The levels of ACE2 protein could correlate with disease severity; for instance, overweight individuals may exhibit higher ACE2 levels, while lower levels in children could explain their reduced prevalence of severe cases.

Next Steps in Research

These preliminary findings offer valuable insights that could pave the way for the development of novel topical antiviral therapies. However, further research is necessary, particularly involving nasal samples from COVID-19 patients, to better understand the implications of ACE2 expression in relation to the virus.

Reference

Mengfei Chen, Wenjuan Shen, Nicholas R. Rowan, Heather Kulaga, Alexander Hillel, Murugappan Ramanathan, Andrew P. Lane. Elevated ACE2 expression in the olfactory neuroepithelium: implications for anosmia and upper respiratory SARS-CoV-2 entry and replication. Eur Respir J 2020; in press (https://doi.org/10.1183/13993003.01948-2020).

Image by Eduardo RS from Pixabay.