Cerebrovascular disease in COVID-19: Is there a higher risk of stroke?

Extracellular Vesicles: The Invisible Heroes and Villains of COVID-19 Central Neuropathology

Acknowledging the neurological symptoms of COVID-19 and the long-lasting neurological damage even after the epidemic ends are common, necessitating ongoing vigilance. Initial investigations suggest that extracellular vesicles (EVs), which assist in the evasion of the host's immune response and achieve immune evasion in SARS-CoV-2 systemic spreading, contribute to the virus's attack on the central nervous system (CNS). The pro-inflammatory, pro-coagulant, and immunomodulatory properties of EVs contents may directly drive neuroinflammation and cerebral thrombosis in COVID-19. Additionally, EVs have attracted attention as potential candidates for targeted therapy in COVID-19 due to their innate homing properties, low immunogenicity, and ability to cross the blood-brain barrier (BBB) freely. Mesenchymal stromal/stem cell (MSCs) secreted EVs are widely applied and evaluated in patients with COVID-19 for their therapeutic effect, considering the limited antiviral treatment. This review summarizes the involvement of EVs in COVID-19 neuropathology as carriers of SARS-CoV-2 or other pathogenic contents, as predictors of COVID-19 neuropathology by transporting brain-derived substances, and as therapeutic agents by delivering biotherapeutic substances or drugs. Understanding the diverse roles of EVs in the neuropathological aspects of COVID-19 provides a comprehensive framework for developing, treating, and preventing central neuropathology and the severe consequences associated with the disease.

Therapeutic Challenges in COVID-19

SARS-CoV2 is a novel respiratory coronavirus and, understanding its molecular mechanism is a prerequisite to developing effective treatment for COVID-19. This RNA genome-carrying virus has a protein coat with spikes (S) that attaches to the ACE2 receptor at the cell surface of human cells. Several repurposed drugs are used to treat COVID-19 patients that are proven to be largely unsuccessful or have limited success in reducing mortalities. Several vaccines are in use to reduce the viral load to prevent developing symptoms. Major challenges to their efficacy include the inability of antibody molecules to enter cells but remain effective in the bloodstream to kill the virus. The efficacy of vaccines also depends on their neutralizing ability to constantly evolve new virus strains due to novel mutations and evolutionary survival dynamics. Taken together, SARS-CoV2 antibody vaccines may not be very effective and other approaches based on genetic, genomic, and protein interactome could be fruitful to identify therapeutic targets to reduce disease-related mortalities.

Neuroprotective Agents with Therapeutic Potential for COVID-19

COVID-19 patients can exhibit a wide range of clinical manifestations affecting various organs and systems. Neurological symptoms have been reported in COVID-19 patients, both during the acute phase of the illness and in cases of long-term COVID. Moderate symptoms include ageusia, anosmia, altered mental status, and cognitive impairment, and in more severe cases can manifest as ischemic cerebrovascular disease and encephalitis. In this narrative review, we delve into the reported neurological symptoms associated with COVID-19, as well as the underlying mechanisms contributing to them. These mechanisms include direct damage to neurons, inflammation, oxidative stress, and protein misfolding. We further investigate the potential of small molecules from natural products to offer neuroprotection in models of neurodegenerative diseases. Through our analysis, we discovered that flavonoids, alkaloids, terpenoids, and other natural compounds exhibit neuroprotective effects by modulating signaling pathways known to be impacted by COVID-19. Some of these compounds also directly target SARS-CoV-2 viral replication. Therefore, molecules of natural origin show promise as potential agents to prevent or mitigate nervous system damage in COVID-19 patients. Further research and the evaluation of different stages of the disease are warranted to explore their potential benefits.

Effects of COVID-19 on Synaptic and Neuronal Degeneration

Neurons are the basic building blocks of the human body's neurological system. Atrophy is defined by the disintegration of the connections between cells that enable them to communicate. Peripheral neuropathy and demyelinating disorders, as well as cerebrovascular illnesses and central nervous system (CNS) inflammatory diseases, have all been linked to brain damage, including Parkinson's disease (PD). It turns out that these diseases have a direct impact on brain atrophy. However, it may take some time after the onset of one of these diseases for this atrophy to be clearly diagnosed. With the emergence of the Coronavirus disease 2019 (COVID-19) pandemic, there were several clinical observations of COVID-19 patients. Among those observations is that the virus can cause any of the diseases that can lead to brain atrophy. Here we shed light on the research that tracked the relationship of these diseases to the COVID-19 virus. The importance of this review is that it is the first to link the relationship between the Coronavirus and diseases that cause brain atrophy. It also indicates the indirect role of the virus in dystrophy.

COVID-19 independently predicts poor outcomes in Acute Ischemic Stroke- Insights from a multicenter study from Pakistan and United Arab Emirates

BACKGROUND

Ischemic stroke associated with coronavirus 2019 (COVID-19) has been well recognized by now. Few studies have compared COVID related versus unrelated strokes. We intend to report on a large group of Asian patients from two countries and compare COVID with non-COVID strokes admitted during the same time period.

METHODS

Consecutive cases of acute ischemic stroke either presenting or developing, between March 2020 and December 2021 in four tertiary care hospitals (1 in Dubai, UAE and 3 in Karachi, Pakistan) and testing positive for COVID-19 were included in the study. Patients admitted with ischemic stroke during the same time period and who tested negative for COVID-19 were also randomly selected from the four hospitals. All data was collected from the medical records of the patients and recorded on a standard questionnaire before it was entered in SPSS version 21 for analysis.

RESULTS

There were 139 COVID positive and 271 COVID negative patients with acute ischemic stroke included in the current study. There were significantly more males (80.6% vs 64.9%, p=0.001) and more large vessel strokes in the COVID positive group (41% vs 21.8%, p<0.001). Being COVID positive was an independent predictor of poor outcome at discharge, defined as a modified Rankin score of 3-6 (OR 3.87, 95% CI 2.21-6.77) after adjusting for country, age, sex, vascular comorbid conditions and stroke subtype.

CONCLUSIONS

In this largest series of patients with COVID related strokes from Asia, COVID-19 was an independent predictor of poor outcomes at discharge after adjusting for other variables.

Acute cerebrovascular events in severe and nonsevere COVID-19 patients: a systematic review and meta-analysis

The degree to which COVID-19 severity influences the development of acute cerebrovascular events (ACVE) is unknown. Therefore, we aimed to describe the prevalence and risk of ACVE in patients with severe and nonsevere COVID-19. We systematically reviewed MEDLINE, EMBASE, Web of Science, and Scopus and identified observational and interventional studies of patients with COVID-19 allocated by respiratory severity that reported ACVE development. Case reports/series were excluded. The main outcome assessed was the pooled rate of ACVE in patients with severe and nonsevere COVID-19. To determine the risk of ACVE development by COVID-19 severity, a meta-analysis was performed. PROSPERO registration number: CRD42020178905. About 19 of 5758 identified studies were analyzed. From 11,886 COVID-19 patients analyzed, 421 had at least one ACVE [3.6%, 95% confidence interval (CI) 2.904-4.179]. Severe COVID-19 increased the risk of ACVE (odds ratio 1.96, 95% CI 1.22-3.15; P = 0.005; I ² = 64%), specifically hemorrhagic stroke (4.12, 2.0-8.53; P = 0.001; I ² = 0%). There was no difference in the risk of developing ischemic stroke between patients with severe and nonsevere COVID-19 (1.53, 0.87-2.7; P = 0.14; I ² = 52%). From the patients who developed any ACVE, those with severe COVID-19 had a greater mortality risk than those with nonsevere COVID-19 (3.85, 1.08-13.70; P = 0.04; I ² = 0%). The main limitations of our study were the heterogeneity found in the main meta-analysis studies and in their reported definition for COVID-19 severity. In conclusion, our findings provide evidence that COVID-19 respiratory severity could lead to ACVE development that increases mortality. The effect of COVID-19 management in ACVE needs to be evaluated.

Increased Incidence of In-Hospital Ischemic Stroke During SARS-CoV-2 Outbreak: A Single-Center Study

BACKGROUND

Meta-analyses of observational studies report a 1.1-1.7% pooled risk of stroke among patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection requiring hospitalization, but consultations for stroke and reperfusion procedures have decreased during the outbreak that occurred during the first half of the year 2020. It is still unclear whether a true increase in the risk of stroke exists among patients with coronavirus disease 2019 (COVID-19). In-hospital ischemic stroke (IHIS) complicated the 0.04-0.06% of all admissions in the pre-COVID-19 era, but its incidence has not been assessed among inpatients with COVID-19. We aimed to compare IHIS incidence among patients with SARS-CoV-2 infection with that of inpatients with non-COVID-19 illnesses from the same outbreak period and from previous periods.

METHODS

This historical cohort study belongs to the COVID-19@Vallecas cohort. The incidence of IHIS was estimated for patients with SARS-CoV-2 hospitalized during March-April 2020 [COVID-19 cohort (CC)], for patients with non-COVID-19 medical illness hospitalized during the same outbreak period [2020 non-COVID-19 cohort (20NCC)], and for inpatients with non-COVID-19 illness admitted during March-April of the years 2016-2019 [historical non-COVID-19 cohort (HNCC)]. Unadjusted risk of IHIS was compared between the three cohorts, and adjusted incidence rate ratio (IRR) of IHIS between cohorts was obtained by means of Poisson regression.

RESULTS

Overall, 8126 inpatients were included in this study. Patients in the CC were younger and more commonly men than those from the HNCC and 20NCC. Absolute risk of IHIS was 0.05% for HNCC, 0.23% for 20NCC, and 0.36% for CC, (p = 0.004 for HNCC vs. CC). Cumulative incidence for IHIS by day nine after admission, with death as a competing risk, was 0.09% for HNCC, 0.23% for 20NCC, and 0.50% for CC. In an adjusted Poisson regression model with sex, age, needing of intensive care unit admission, and cohort (HNCC as reference) as covariates, COVID-19 was an independent predictor for IHIS (IRR 6.76, 95% confidence interval 1.66-27.54, p = 0.01). A nonsignificant increase in the risk of IHIS was observed for the 20NCC (IRR 5.62, 95% confidence interval 0.93-33.9, p = 0.06).

CONCLUSIONS

SARS-CoV-2 outbreak was associated with an increase in the incidence of IHIS when compared with inpatients from a historical cohort. Viral infection itself may be related to the increased risk of IHIS among patients with COVID-19, but in view of our results from the 20NCC, it is likely that other factors, such as hospital saturation and overwhelming of health systems, may have played a role in the increased frequency of IHIS.

Emerging COVID-19 Neurological Manifestations: Present Outlook and Potential Neurological Challenges in COVID-19 Pandemic

The unremitting coronavirus disease 2019 (COVID-19) pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) marked a year-long phase of public health adversaries and has severely compromised healthcare globally. Early evidence of COVID-19 noted its impact on the pulmonary and cardiovascular functions, while multiple studies in recent time shed light on its substantial neurological complications, though a comprehensive understanding of the cause(s), the mechanism(s), and their neuropathological outcomes is scarce. In the present review, we conferred evidence of neurological complications in COVID-19 patients and shed light on the SARS-CoV-2 infection routes including the hematogenous, direct/neuronal, lymphatic tissue or cerebrospinal fluid, or infiltration through infected immune cells, while the underlying mechanism of SARS-CoV-2 invasion to the central nervous system (CNS) was also discussed. In an up-to-date manner, we further reviewed the impact of COVID-19 in developing diverse neurologic manifestations associated with CNS, peripheral nervous system (PNS), skeletal muscle, and also pre-existing neurological diseases, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, epilepsy, and myasthenia gravis. Furthermore, we discussed the involvement of key factors including age, sex, comorbidity, and disease severity in exacerbating the neurologic manifestations in COVID-19 patients. An outlook of present therapeutic strategies and state of existing challenges in COVID-19 management was also accessed. Conclusively, the present report provides a comprehensive review of COVID-19-related neurological complications and emphasizes the need for their early clinical management in the ongoing COVID-19 pandemic.

Understanding the Role of Blood Vessels in the Neurologic Manifestations of Coronavirus Disease 2019 (COVID-19)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was originally identified as an outbreak in Wuhan, China, toward the end of 2019 and quickly became a global pandemic, with a large death toll. Originally identified as a respiratory disease, similar to previously discovered SARS and Middle East respiratory syndrome (MERS), concern has since been raised about the effects of SARS-CoV-2 infection on the vasculature. This viral-vascular involvement is of particular concern with regards to the small vessels present in the brain, with mounting evidence demonstrating that SARS-CoV-2 is capable of crossing the blood-brain barrier. Severe symptoms, termed coronavirus disease 2019 (COVID-19), often result in neurologic complications, regardless of patient age. These neurologic complications range from mild to severe across all demographics; however, the long-term repercussions of neurologic involvement on patient health are still unknown.

The Other Side of SARS-CoV-2 Infection: Neurological Sequelae in Patients

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread around the globe causing coronavirus disease 2019 (COVID-19). Because it affects the respiratory system, common symptoms are cough and breathing difficulties with fever and fatigue. Also, some cases progress to acute respiratory distress syndrome (ARDS). The acute phase of COVID-19 has been also related to nervous system symptoms, including loss of taste and smell as well as encephalitis and cerebrovascular disorders. However, it remains unclear if neurological complications are due to the direct viral infection of the nervous system, or they appear as a consequence of the immune reaction against the virus in patients who presented pre-existing deficits or had a certain detrimental immune response. Importantly, the medium and long-term consequences of the infection by SARS-CoV-2 in the nervous system remain at present unknown. This review article aims to give an overview of the current neurological symptoms associated with COVID-19, as well as attempting to provide an insight beyond the acute affectation.

Neurological manifestations in patients with symptomatic COVID-19 admitted to the Bafoussam Regional Hospital, Cameroon

INTRODUCTION

although the main manifestations of COVID-19 are respiratory, several neurological symptoms and complications have also been reported. The pandemic seems to have some epidemiological specificities in sub-Saharan Africa, and this may be reflected in the type and frequency of neurological symptoms. This study aimed to report neurological manifestations associated with symptomatic COVID-19 in a sub-Saharan African setting.

METHODS

we conducted a retrospective review of symptomatic PCR-confirmed COVID-19 cases admitted to the Bafoussam Regional Hospital between March and September 2020. Patients' files were reviewed at discharge by a consultant neurologist. Socio-demographic characteristics, co-morbidities, symptoms on admission, neurological symptoms during hospitalization, management, and in-hospital outcome were recorded. Comparisons between patients with and without neurological symptoms were performed using Fisher's exact and Mann-Whitney U test.

RESULTS

we enrolled 177 symptomatic patients (68% men). Mean age was 54.6 ± 17.8 years (range 2-99 years). Co-morbidities were present in 57.6% of patients, including hypertension (27.1%) and diabetes mellitus (25.4%). Neurological symptoms were found in 113 (63.8%) patients. The most frequent were headache (39.0%), myalgia (35.6%), anosmia (11.9%), impaired consciousness (10.7%) and delirium (5.6%). Regarding the presenting symptoms, fever was more frequent in patients with neurological symptoms than in those without (81.4% versus 50.0%, p< 0.001), while digestive symptoms were less frequent in patients with neurological symptoms (0.9% versus 9.4%, p= 0.004).

CONCLUSION

neurological manifestations are frequent and heterogeneous in patients with symptomatic COVID-19. Further studies are needed to clarify the pathophysiology of neurological symptoms in COVID-19 and their impact on patients' long-term outcome.

The Impact of SARS-CoV-2 Infection on the Development of Neurodegeneration in Multiple Sclerosis

The novel coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global challenge. Currently, there is some information on the consequences of COVID-19 infection in multiple sclerosis (MS) patients, as it is a newly discovered coronavirus, but its far-reaching effects on participation in neurodegenerative diseases seem to be significant. Recent cases reports showed that SARS-CoV-2 may be responsible for initiating the demyelination process in people who previously had no symptoms associated with any nervous system disorders. It is presently known that infection of SARS-CoV-2 evokes cytokine storm syndrome, which may be one of the factors leading to the acute cerebrovascular disease. One of the substantial problems is the coexistence of cerebrovascular disease and MS in an individual's life span. Epidemiological studies showed an enhanced risk of death rate from vascular disabilities in MS patients of approximately 30%. It has been demonstrated that patients with severe SARS-CoV-2 infection usually show increased levels of D-dimer, fibrinogen, C-reactive protein (CRP), and overactivation of blood platelets, which are essential elements of prothrombotic events. In this review, the latest knowledge gathered during an ongoing pandemic of SARS-CoV-2 infection on the neurodegeneration processes in MS is discussed.

Stroke in Africa: profile, progress, prospects and priorities

Stroke is a leading cause of disability, dementia and death worldwide. Approximately 70% of deaths from stroke and 87% of stroke-related disability occur in low-income and middle-income countries. At the turn of the century, the most common diseases in Africa were communicable diseases, whereas non-communicable diseases, including stroke, were considered rare, particularly in sub-Saharan Africa. However, evidence indicates that, today, Africa could have up to 2-3-fold greater rates of stroke incidence and higher stroke prevalence than western Europe and the USA. In Africa, data published within the past decade show that stroke has an annual incidence rate of up to 316 per 100,000, a prevalence of up to 1,460 per 100,000 and a 3-year fatality rate greater than 80%. Moreover, many Africans have a stroke within the fourth to sixth decades of life, with serious implications for the individual, their family and society. This age profile is particularly important as strokes in younger people tend to result in a greater loss of self-worth and socioeconomic productivity than in older individuals. Emerging insights from research into stroke epidemiology, genetics, prevention, care and outcomes offer great prospects for tackling the growing burden of stroke on the continent. In this article, we review the unique profile of stroke in Africa and summarize current knowledge on stroke epidemiology, genetics, prevention, acute care, rehabilitation, outcomes, cost of care and awareness. We also discuss knowledge gaps, emerging priorities and future directions of stroke medicine for the more than 1 billion people who live in Africa.

Involvement of the nervous system in COVID-19: The bell should toll in the brain

The world is fuming at SARS-CoV-2 for being the culprit for causing the devastating COVID-19, claiming millions of lives across the globe in the form of respiratory disorders. But lesser known are its effects on the CNS that are slowly surfacing in the worldwide population. Our review illustrates findings that claim SARS-CoV-2's arrival onto the ACE2 receptors of neuronal and glial cells mainly via CSF, olfactory nerve, trigeminal nerve, neuronal dissemination, and hematogenous pathways. The role of SARS-CoV-2 structural proteins in its smooth viral infectivity of the host cannot be ignored, especially the spike proteins that mediate spike attachment and host membrane fusion. Worth mentioning the nucleocapsid, envelope, and membrane proteins make the proliferation of SARS-CoV-2 much simpler than expected in spreading infection. This has led to catastrophic conditions like seizures, Guillain-Barré syndrome, viral encephalitis, meningoencephalitis, acute cerebrovascular disease, and respiratory failures. Placing a magnifying lens on the lesser-explored CNS consequences of COVID-19, we attempt to shift the focus of our readers onto the new supporting threats to which further studies are needed.

Understanding the Immunologic Characteristics of Neurologic Manifestations of SARS-CoV-2 and Potential Immunological Mechanisms

Similar to its predecessors, coronavirus disease 2019 (COVID-19) exhibits neurotrophic properties, which lead to progression of neurologic sequelae. Besides direct viral invasion to the central nervous system (CNS), indirect CNS involvement through viral-mediated immune response is plausible. Aberrant immune pathways such as extreme release of cytokines (cytokine storm), autoimmunity mediated by cross-reactivity between CNS components and viral particles, and microglial activation propagate CNS damage in these patients. Here, we review the currently available evidence to discuss the plausible immunologic pathways that may contribute to the development of COVID-19 neurological complications, namely Alzheimer's disease, Parkinson's disease, stroke, multiple sclerosis, Guillain-Barre syndrome, seizure, and brainstem involvement.

Down's syndrome and COVID-19: risk or protection factor against infection? A molecular and genetic approach

Down syndrome (DS) is the most common genetic cause of learning difficulties and intellectual disabilities. DS patients often present with several congenital defects and chronic diseases, including immunity disorders. Elevated levels of pro-inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α) have been seen, which appear to vary with age. At birth, patients present with combined immunodeficiency, with frequent infections that decrease with age. Furthermore, high levels of IL-4 and IL-10 with anti-inflammatory properties and low levels of IL-6 and TNF-α are described in children. The immune system is believed to play an essential role in SARS-CoV-2 pathogenesis, and it has been associated with elevated levels of pro-inflammatory cytokines and an exaggerated cytokine release syndrome (CRS) that may eventually trigger a severe situation called cytokine storm. On the other hand, genetic features seem to be involved in the predisposition to illness and its severity. Overexpression of DSCR1 and ZAKI-4 inhibits the translocation of activated T lymphocyte nuclear factor (NF-AT) to the nucleus, a main step in the inflammatory responsiveness. We discuss here the possible role of immunology and genetic features of DS in the infection and prognosis in COVID-19.

Stroke in COVID-19: A systematic review and meta-analysis

Background

Coronavirus disease 2019 (COVID-19) has become a global pandemic, affecting millions of people. However, the relationship between COVID-19 and acute cerebrovascular diseases is unclear.

Aims

We aimed to characterize the incidence, risk factors, clinical–radiological manifestations, and outcome of COVID-19-associated stroke.

Methods

Three medical databases were systematically reviewed for published articles on acute cerebrovascular diseases in COVID-19 (December 2019–September 2020). The review protocol was previously registered (PROSPERO ID = CRD42020185476). Data were extracted from articles reporting ≥5 stroke cases in COVID-19. We complied with the PRISMA guidelines and used the Newcastle–Ottawa Scale to assess data quality. Data were pooled using a random-effect model.

Summary of review

Of 2277 initially identified articles, 61 (2.7%) were entered in the meta-analysis. Out of 108,571 patients with COVID-19, acute CVD occurred in 1.4% (95%CI: 1.0–1.9). The most common manifestation was acute ischemic stroke (87.4%); intracerebral hemorrhage was less common (11.6%). Patients with COVID-19 developing acute cerebrovascular diseases, compared to those who did not, were older (pooled median difference = 4.8 years; 95%CI: 1.7–22.4), more likely to have hypertension (OR = 7.35; 95%CI: 1.94–27.87), diabetes mellitus (OR = 5.56; 95%CI: 3.34–9.24), coronary artery disease (OR = 3.12; 95%CI: 1.61–6.02), and severe infection (OR = 5.10; 95%CI: 2.72–9.54). Compared to individuals who experienced a stroke without the infection, patients with COVID-19 and stroke were younger (pooled median difference = −6.0 years; 95%CI: −12.3 to −1.4), had higher NIHSS (pooled median difference = 5; 95%CI: 3–9), higher frequency of large vessel occlusion (OR = 2.73; 95%CI: 1.63–4.57), and higher in-hospital mortality rate (OR = 5.21; 95%CI: 3.43–7.90).

Conclusions

Acute cerebrovascular diseases are not uncommon in patients with COVID-19, especially in those whom are severely infected and have pre-existing vascular risk factors. The pattern of large vessel occlusion and multi-territory infarcts suggests that cerebral thrombosis and/or thromboembolism could be possible causative pathways for the disease.