French scientists of the Pasteur Institute, the National Center for Scientific Research, the University of Paris and other scientific organizations explained the mechanisms of the main symptom at Coronavirus – the loss of smell (anosmia) in patients at different stages of the disease. The article of the researchers was published in the journal Science Translational Medicine, briefly about scientific work describes the press release on MedicalXpress.
Experts found out that SARS-COV-2 strikes touch neurons and causes inflammation of the epithelium and an olfactory nervous system. In addition, in some patients with persistent clinical signs, anosmia is associated with long-term inflammation of the epithelial and olfactory nervous system and a long-term presence of a virus (for several months) in the olfactory epithelium.
Due to viral infection, touch neurons lose the olfactory cilia that are necessary for the “catching” of irritant molecules. The virus also penetrates sensory neurons, disrupting their functions, and contributes to the death of epithelium cells as a result of apoptosis (programmable cell death). In the future, the coronavirus penetrates the olfactory bulb, where inflammatory reactions provokes, and from there applies to other nervous structures.
Penetration of the virus through the olfactory bulbs in the brain explains why some patients develop various psychological clinical signs (alarming disorders, depression) or neurological symptoms (reducing cognitive functions, predisposition to the development of neurodegenerative diseases).