SARS-CoV-2 journey to the brain with a focus on potential role of docosahexaenoic acid bioactive lipid mediators.

Coronavirus Disease 2019 or COVID-19 have infected till day 82,579,768 confirmed cases including 1,818,849 deaths, reported by World Health Organization WHO. COVID-19, originated by Severe Acute respiratory syndrome Coronavirus 2 (SARS-CoV-2), contributes to respiratory distress in addition to neurological symptoms in some patients. In the current review, we focused on the neurological complications associated with COVID-19. We discussed different pathways followed by RNA-virus, especially Flaviviridae family in the brain and passage through the Blood-Brain-Barrier BBB. Then, we explored SARS-CoV-2 mechanisms responsible of neuroinvasion and BBB disruption as well as the immunopathogenesis of SARS-CoV-2 in the central nervous system CNS. Since SARS-CoV-2 is an enveloped virus, enclosed in a lipid bilayer and that lipids are essential cell components playing numerous biological roles in viral infection and replication, we investigated the lipid metabolism remodeling upon coronavirus replication. We also highlighted the anti-inflammatory and neuroprotective potential of an omega-3 polyunsaturated fatty acid, docosahexaenoic acid DHA, as well as several bioactive lipid mediators. Altogether, our data allow better understanding of SARS-CoV-2 neuroinvasion and could assist in drug targeting to decline the burden of short-term and long-term neurological manifestations of SARS-CoV-2.

Viral infections and their relationship to neurological disorders.

The chronic dysfunction of neuronal cells, both central and peripheral, a characteristic of neurological disorders, may be caused by irreversible damage and cell death. In 2016, more than 276 million cases of neurological disorders were reported worldwide. Moreover, neurological disorders are the second leading cause of death. Generally, the etiology of neurological diseases is not fully understood. Recent studies have related the onset of neurological disorders to viral infections, which may cause neurological symptoms or lead to immune responses that trigger these pathological signs. Currently, this relationship is mostly based on epidemiological data on infections and seroprevalence of patients who present with neurological disorders. The number of studies aiming to elucidate the mechanism of action by which viral infections may directly or indirectly contribute to the development of neurological disorders has been increasing over the years but these studies are still scarce. Comprehending the pathogenesis of these diseases and exploring novel theories may favor the development of new strategies for diagnosis and therapy in the future. Therefore, the objective of the present study was to review the main pieces of evidence for the relationship between viral infection and neurological disorders such as Alzheimer's disease, Parkinson's disease, Guillain-Barré syndrome, multiple sclerosis, and epilepsy. Viruses belonging to the families Herpesviridae, Orthomyxoviridae, Flaviviridae, and Retroviridae have been reported to be involved in one or more of these conditions. Also, neurological symptoms and the future impact of infection with SARS-CoV-2, a member of the family Coronaviridae that is responsible for the COVID-19 pandemic that started in late 2019, are reported and discussed.