Comprehensive Review on Neuro-COVID-19 Pathophysiology and Clinical Consequences

SARS-CoV-2 infection and spontaneous spinal hemorrhage: a systematic review

The neurological manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, including spontaneous spinal hemorrhage (SSH), are diverse. SSH is a detrimental neurosurgical event requiring immediate medical attention. We aimed to investigate the association between SARS-CoV-2 and SSH and delineate a rational clinical approach. The authors searched PubMed, Scopus, Web of Science, and Google Scholar for studies published up to January 25, 2023, on SSH and SARS-CoV-2 infection. For each dataset, the authors performed pooled estimates examining three outcomes of interest: (1) early post-intervention neurological status, (2) mortality, and (3) post-intervention neurological rehabilitation outcomes. After reviewing 1341 results, seven datasets were identified for the final analysis. Fifty-seven percent of patients were females. Twenty-eight percent of the patients experienced severe systemic infection. The mean interval between the SARS-CoV-2 infection and neurological presentation was 18 days. Pain and sensorimotor deficits were the most common (57%). Spinal epidural hematoma (EDH) was the most common presentation (71.4%). Three patients were treated conservatively, while 4 received neurosurgical intervention. Pain and sensorimotor deficits had the best treatment response (100%), while the sphincter had the worst response (0%). Long-term follow-up showed that 71% of patients had good recovery. SARS-CoV-2-associated SSH is a rare complication of infection, with an often insidious presentation that requires high clinical suspicion. Patients with SARS-CoV-2 infection and new neurological symptoms or disproportionate neck or back pain require a neuroaxis evaluation. Neurosurgical intervention and conservative management are both viable options to treat SSH following COVID-19. Still, a homogenous approach to the treatment paradigm of SSH cannot be obtained, but lesions with space-occupying effects are suitable for neurosurgical evacuation-decompression while more indolent lesions could be treated conservatively. These options should be tailored individually until larger studies provide a consensus.

Immune-mediated cerebellitis following SARS-CoV-2 infection-a case report and review of the literature

The coronavirus disease 2019 (COVID-19) can be associated with a wide variety of neurological manifestations. Some of these manifestations might result from the ongoing systemic inflammatory state, but the pathophysiology of specific neurologic involvement is still unclear. In this article, we report a patient who developed an isolated cerebellar syndrome 9 weeks after an episode of COVID-19. The reverse-transcriptase polymerase chain reaction (RT-PCR) for SARS-CoV-2 was positive on cerebrospinal fluid (CSF). A post-infectious-autoimmune-cerebellitis following COVID-19 was suspected, and the patient was treated with corticosteroids, leading to a complete recovery within a few weeks. We review the other cases of COVID-19-associated cerebellar syndrome reported so far and discuss the potential pathophysiological mechanisms underlying this neurologic manifestation.

SARS-CoV-2 infection might be a predictor of mortality in intracerebral hemorrhage

BACKGROUND

SARS-CoV-2 infection may be associated with uncommon complications such as intracerebral hemorrhage (ICH), with a high mortality rate. We compared a series of hospitalized ICH cases infected with SARS-CoV-2 with a non-SARS-CoV-2 infected control group and evaluated if the SARS-CoV-2 infection is a predictor of mortality in ICH patients.

METHODS

In a multinational retrospective study, 63 cases of ICH in SARS-CoV-2 infected patients admitted to 13 tertiary centers from the beginning of the pandemic were collected. We compared the clinical and radiological characteristics and in-hospital mortality of these patients with a control group of non-SARS-CoV-2 infected ICH patients of a previous cohort from the country where the majority of cases were recruited.

RESULTS

Among 63 ICH patients with SARS-CoV-2 infection, 23 (36.5%) were women. Compared to the non-SARS-CoV-2 infected control group, in SARS-CoV-2 infected patients, ICH occurred at a younger age (61.4 ± 18.1 years versus 66.8 ± 16.2 years, P = 0.044). These patients had higher median ICH scores ([3 (IQR 2-4)] versus [2 (IQR 1-3)], P = 0.025), a more frequent history of diabetes (34% versus 16%, P = 0.007), and lower platelet counts (177.8 ± 77.8 × 10⁹/L versus 240.5 ± 79.3 × 10⁹/L, P < 0.001). The in-hospital mortality was not significantly different between cases and controls (65% versus 62%, P = 0.658) in univariate analysis; however, SARS-CoV-2 infection was significantly associated with in-hospital mortality (aOR = 4.3, 95% CI: 1.28-14.52) in multivariable analysis adjusting for potential confounders.

CONCLUSION

Infection with SARS-CoV-2 may be associated with increased odds of in-hospital mortality in ICH patients.

The contribution of gut-brain axis to development of neurological symptoms in COVID-19 recovered patients: A hypothesis and review of literature

The gut microbiota undergoes significant alterations in response to viral infections, particularly the novel SARS-CoV-2. As impaired gut microbiota can trigger numerous neurological disorders, we suggest that the long-term neurological symptoms of COVID-19 may be related to intestinal microbiota disorders in these patients. Thus, we have gathered available information on how the virus can affect the microbiota of gastrointestinal systems, both in the acute and the recovery phase of the disease, and described several mechanisms through which this gut dysbiosis can lead to long-term neurological disorders, such as Guillain-Barre syndrome, chronic fatigue, psychiatric disorders such as depression and anxiety, and even neurodegenerative diseases such as Alzheimer's and Parkinson's disease. These mechanisms may be mediated by inflammatory cytokines, as well as certain chemicals such as gastrointestinal hormones (e.g., CCK), neurotransmitters (e.g., 5-HT), etc. (e.g., short-chain fatty acids), and the autonomic nervous system. In addition to the direct influences of the virus, repurposed medications used for COVID-19 patients can also play a role in gut dysbiosis. In conclusion, although there are many dark spots in our current knowledge of the mechanism of COVID-19-related gut-brain axis disturbance, based on available evidence, we can hypothesize that these two phenomena are more than just a coincidence and highly recommend large-scale epidemiologic studies in the future.

[Molecular basis of biological activity of polysaccharides in COVID-19 associated conditions]

The review considers the main molecular biological features of the COVID-19 causative agent, the SARS-CoV-2 virus: life cycle, viral cell penetration strategies, interactions of viral proteins with human proteins, cytopathic effects. We also analyze pathological conditions that occur both during the course of the COVID-19 disease and after virus elimination. A brief review of the biological activities of polysaccharides isolated from various sources is given, and possible molecular biological mechanisms of these activities are considered. Data analysis shows that polysaccharides are a class of biological molecules with wide potential for use in the treatment of both acute conditions in COVID-19 and post-COVID syndrome.

Acute ischemic stroke and vaccine-induced immune thrombotic thrombocytopenia post COVID-19 vaccination; a systematic review

INTRODUCTION

One of the rare but potentially serious side effects of COVID-19 vaccination is arterial and venous thrombosis. Acute ischemic stroke (AIS) cases have been reported post COVID-19 vaccination. Herein, we systematically reviewed the reported cases of AIS after COVID-19 vaccination.

METHOD

This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. We searched PubMed and Scopus until April 14, 2022 to find studies that reported AIS post COVID-19 vaccination.

RESULTS

We found 447 articles. From those, 140 duplicates were removed. After screening and excluding irrelevant articles, 29 studies (43 patients) were identified to be included. From all cases, 22 patients (51.1%) were diagnosed with AIS associated with Vaccine-induced immune thrombotic thrombocytopenia (VITT). Among AIS associated with VITT group, all received viral vector vaccines except one. The majority of cases with AIS and VITT were female (17 cases, 77.2%) and aged below 60 years (15 cases, 68%). Fourteen patients (32.5%) had additional thrombosis in other sites. Four of them (0.09%) showed concurrent CVST and ischemic stroke. Hemorrhagic transformation following AIS occurred in 7 patients (16.27%). Among 43 patients with AIS, at least 6 patients (14%) died during hospital admission.

CONCLUSION

AIS has been reported as a rare complication within 4 weeks post COVID-19 vaccination, particularly with viral vector vaccines. Health care providers should be familiar with this rare consequence of COVID-19 vaccination in particular in the context of VITT to make a timely diagnosis and appropriate treatment plan.

The neuroinvasiveness, neurotropism, and neurovirulence of SARS-CoV-2

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection is associated with a diverse spectrum of neurological complications during the acute and postacute stages. The pathogenesis of these complications is complex and dependent on many factors. For accurate and consistent interpretation of experimental data in this fast-growing field of research, it is essential to use terminology consistently. In this article, we outline the distinctions between neuroinvasiveness, neurotropism, and neurovirulence. Additionally, we discuss current knowledge of these distinct features underlying the pathogenesis of SARS-CoV-2-associated neurological complications. Lastly, we briefly discuss the advantages and limitations of different experimental models, and how these approaches can further be leveraged to advance the field.

Hamster organotypic modeling of SARS-CoV-2 lung and brainstem infection

SARS-CoV-2 has caused a global pandemic of COVID-19 since its emergence in December 2019. The infection causes a severe acute respiratory syndrome and may also spread to central nervous system leading to neurological sequelae. We have developed and characterized two new organotypic cultures from hamster brainstem and lung tissues that offer a unique opportunity to study the early steps of viral infection and screening antivirals. These models are not dedicated to investigate how the virus reaches the brain. However, they allow validating the early tropism of the virus in the lungs and demonstrating that SARS-CoV-2 could infect the brainstem and the cerebellum, mainly by targeting granular neurons. Viral infection induces specific interferon and innate immune responses with patterns specific to each organ, along with cell death by apoptosis, necroptosis, and pyroptosis. Overall, our data illustrate the potential of rapid modeling of complex tissue-level interactions during infection by a newly emerged virus.

PPAR Gamma and Viral Infections of the Brain

Peroxisome Proliferator-Activated Receptor gamma (PPARγ) is a master regulator of metabolism, adipogenesis, inflammation and cell cycle, and it has been extensively studied in the brain in relation to inflammation or neurodegeneration. Little is known however about its role in viral infections of the brain parenchyma, although they represent the most frequent cause of encephalitis and are a major threat for the developing brain. Specific to viral infections is the ability to subvert signaling pathways of the host cell to ensure virus replication and spreading, as deleterious as the consequences may be for the host. In this respect, the pleiotropic role of PPARγ makes it a critical target of infection. This review aims to provide an update on the role of PPARγ in viral infections of the brain. Recent studies have highlighted the involvement of PPARγ in brain or neural cells infected by immunodeficiency virus 1, Zika virus, or human cytomegalovirus. They have provided a better understanding on PPARγ functions in the infected brain, and revealed that it can be a double-edged sword with respect to inflammation, viral replication, or neuronogenesis. They unraveled new roles of PPARγ in health and disease and could possibly help designing new therapeutic strategies.