COVID-19-Associated Cerebrovascular Events: A Case Series Study and a Literature Review of Possible Mechanisms

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affects multiple body systems, including the nervous system. Cerebrovascular accidents can also occur. Patients with comorbid illnesses have severe manifestations and poor outcomes. Despite the proper mechanism of SARS-CoV-2 infection-associated stroke having not yet been settled, various possible mechanisms have been hypothesized. One possibility is that the virus causes endothelial dysfunction and immune-mediated injury. Another possibility is that the trans-neuronal spread of the virus affects brain tissue. In addition, hypercoagulability caused by SARS-CoV-2 infection could lead to a stroke. A virus-induced dysfunction of the renin-angiotensin system could also lead to a stroke. The immune response and vasculitis resulting from SARS-CoV-2 infection are also possible causes via a cytokine storm, immune dysfunction, and various inflammatory responses. SARS-CoV-2 infection may affect calcitonin gene-related peptides and cerebral blood flow and may lead to stroke. Finally, SARS-CoV-2 may cause hemorrhagic strokes via mechanisms stimulated by its interaction with angiotensin-converting enzyme 2 (ACE2), leading to arterial wall damage and blood pressure changes. In this article, we will present seven cases of stroke-associated SARS-CoV-2 infection.

Calcitonin gene-related peptide: A biomarker for stroke in SARS-CoV-2 infection?

COVID-19 infection was mainly associated with respiratory symptoms, but lately, ischemic stroke (IS) has been reported in several cases. The incidence of IS in SARS-CoV-2 infection is increasing, and its mechanism is still not fully understood. Calcitonin gene-related peptide (CGRP) -the abundantly expressed protein in the peripheral and central nervous system- showed low expression in SARS-CoV-2 patients. This peptide is strongly implicated in regulating cerebral blood flow (CBF) and improving neurological deficits after cerebral arterial occlusion. We assume that a possible interplay between the low circulating levels of CGRP may affect CBF, thus worsening the symptoms of IS in SARS-CoV-2 patients.