So far, COVID-19 has been primarily known as a respiratory disease, but there is growing evidence that the infection and its effects can severely affect other organs, including the brain. Ádám Dénes, a researcher at the Research Institute of Experimental Medicine, the Research Center of the Hungarian Academy of Sciences, and his colleagues are the first in the world to undertake the task of mapping the possible neurological effects of the infection caused by the new coronavirus.
The main symptoms of the coronavirus that we have heard about every day in recent months, are severe pneumonia and respiratory problems, and the virus was even named SARS-CoV-2, where the first half of the acronym comes from the severe acute respiratory syndrome, which makes it even clearer that the disease primarily causes respiratory symptoms. However, when people contract a disease, foreign substances entering our body – cell walls of bacteria, genetic material of a virus, or protein shells – trigger inflammatory reactions. These spread in the body in the form of various inflammatory factors through the circulatory system. By switching the body to “emergency mode,” it is forced to redirect many of its organ systems that function properly in a normal situation to emergency mode as well.
As more and more clinical data becomes available about the disease, there is growing evidence that both the nervous system and the brain may be affected by the virus, and it is conceivable that research in this area may be crucial in the most severe cases. This is why a Hungarian research group is now mapping the possible neurological effects of the new coronavirus infection.
There has been a significant number of deaths where acute respiratory symptoms did not explain the cause of death, as the lungs were in relatively good condition, causing researchers to believe that these deaths point to neurological problems. Although previous studies have confirmed that the coronavirus affects the brain, including a study in Wuhan of 214 hospital patients that showed a third of them lost their sense of taste, smell, and vision, the Hungarian study will be the first to explore how the coronavirus enters the brain and causes damage and in many cases, death.
Loss of smell and taste may also indicate that the virus travels from the nose along the nerve pathways to the olfactory bulb in the brain. But it can also travel through the peripheral nerves or through the walls of cerebral vessels to the medulla, the respiratory center, or the hypothalamus. Either of these could have happened in the above-mentioned cases where coronavirus-infected people with great lung condition were hospitalized. It is not at all uncommon for viruses to be able to spread through the synapses (junctions) of nerve cells, such as the herpes virus, or the H2N2 flu.
More and more pathologists and intensive care physicians also believe that the knowledge gained in this field could play a serious and direct role in treating coronavirus patients. These are also supported by the results of network analysis research on the relationships between humans and coronavirus proteins by well-known Hungarian network scientist Albert-László Barabási, which also suggests that the involvement of the nervous system may be significant in the new coronavirus infection.
The aim of the Hungarian research will be to find out if the virus can infect the nervous system and, if so, which areas of the brain may be affected. They will also study how the local or systemic inflammatory processes caused by a viral infection affect the brain. For their research, they will be the first in the world to study the nerve tissue samples of patients who died of COVID-19.
If the mechanisms of the effects of the virus on the brain and the nervous system can be elucidated, it is possible that some antiviral agents could also improve the survival chances of patients by reducing the viral infection of the nervous system. But it could also provide a chance to specifically inhibit the inflammatory processes in the brain caused by the new coronavirus – possibly with approved drugs that are already on the market to treat other diseases.
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