Inflammatory Cytokine Patterns Associated with Neurological Diseases in Coronavirus Disease 2019

Neuropsychiatric complications of coronavirus disease 2019: Mount Sinai Health System cohort study

OBJECTIVE

To describe the frequency of neuropsychiatric complications among hospitalized patients with coronavirus disease 2019 (COVID-19) and their association with pre-existing comorbidities and clinical outcomes.

METHODS

We retrospectively identified all patients hospitalized with COVID-19 within a large multicenter New York City health system between March 15, 2020 and May 17, 2021 and randomly selected a representative cohort for detailed chart review. Clinical data, including the occurrence of neuropsychiatric complications (categorized as either altered mental status [AMS] or other neuropsychiatric complications) and in-hospital mortality, were extracted using an electronic medical record database and individual chart review. Associations between neuropsychiatric complications, comorbidities, laboratory findings, and in-hospital mortality were assessed using multivariate logistic regression.

RESULTS

Our study cohort consisted of 974 patients, the majority were admitted during the first wave of the pandemic. Patients were treated with anticoagulation (88.4%), glucocorticoids (24.8%), and remdesivir (10.5%); 18.6% experienced severe COVID-19 pneumonia (evidenced by ventilator requirement). Neuropsychiatric complications occurred in 58.8% of patients; 39.8% experienced AMS; and 19.0% experienced at least one other complication (seizures in 1.4%, ischemic stroke in 1.6%, hemorrhagic stroke in 1.0%) or symptom (headache in 11.4%, anxiety in 6.8%, ataxia in 6.3%). Higher odds of mortality, which occurred in 22.0%, were associated with AMS, ventilator support, increasing age, and higher serum inflammatory marker levels. Anticoagulant therapy was associated with lower odds of mortality and AMS.

CONCLUSION

Neuropsychiatric complications of COVID-19, especially AMS, were common, varied, and associated with in-hospital mortality in a diverse multicenter cohort at an epicenter of the COVID-19 pandemic.

Neuropsychological Symptoms and Quality of Life during the COVID-19 Pandemic in Children: A Survey in a Pediatric Population in the Abruzzo Region, Italy

BACKGROUND

The SARS-CoV-2 pandemic has significantly affected the pediatric population. Long-term sequelae (Long COVID-19) may particularly involve the central nervous system, with possible effects on psychological well-being and quality of life (QoL), aspects that were already influenced by the restrictive measures and general social impact of the pandemic.

METHODS

We conducted a cross-sectional survey that aims at investigating the neuropsychological effects and the QoL impairment of SARS-CoV-2 on a cohort of children and adolescents in the Abruzzo region (Italy). A questionnaire was submitted to caregivers with the help of the PEDIATOTEM platform. A control group of healthy subjects was also included to distinguish between the effects of infection from the general influence of the pandemic.

RESULTS

A total of 569 subjects responded: 396 COVID-19 patients (99 of whom had Long COVID-19) and 111 controls. After the pandemic, when compared with the COVID-19 group, the controls reported significantly increased appetite, sleeping habits, and time spent remotely with friends and a reduction in physical activity and time spent in person with friends. A significant higher rate of controls asked for psychological/medical support for emotional problems. On the other hand, the Long COVID-19 group showed more fatigue and emotional instability with respect to non-Long-COVID-19 subjects. No differences in QoL results (EuroQOL) were found between the COVID-19 patients and controls, while the Long-COVID-19 subgroup showed significantly higher rates of pain/discomfort and mood instability, as confirmed by the analysis of variation of responses from the pre-COVID-19 to the post-COVID-19 period.

CONCLUSIONS

Among COVID-19 patients, neuropsychological and QoL impairment was more evident in the Long COVID-19 subgroup, although emotional and relational issues were also reported by uninfected patients, with a growing request for specialist support as a possible consequence of social restriction.

Follow-up of cognitive impairment and inflammatory profile in individuals with mild COVID-19

Individuals who experience mild COVID-19 can suffer from long-lasting cognitive symptoms. Notably, 26% of these individuals experience difficulties with visuospatial abilities six months after infection. However, among those who initially exhibited visuoconstructive impairments, 66% showed improvement or complete reversal over time. Additionally, changes in cytokine levels, particularly CCL11, HGF, and CXCL10, were observed. These results suggest a potential link between ongoing cognitive issues and elevated levels of pro-inflammatory cytokines, which merits further investigation.

Impact of COVID-19 on Anxiety and Depression - Biopsychosocial Factors

Anxiety and depression are prevalent mental disorders around the world. The etiology of both diseases is multifactorial, involving biological and psychological issues. The COVID-19 pandemic settled in 2020 and culminated in several changes in the routine of individuals around the world, affecting mental health. People infected with COVID-19 are at greater risk of developing anxiety and depression, and individuals previously affected by these disorders have worsened the condition. In addition, individuals diagnosed with anxiety or depression before being affected by COVID-19 developed the severe illness at higher rates than individuals without mental disorders. This harmful cycle involves several mechanisms, including systemic hyper-inflammation and neuroinflammation. Furthermore, the context of the pandemic and some previous psychosocial factors can aggravate or trigger anxiety and depression. Disorders are also risks for a more severe picture of COVID-19. This review discusses research on a scientific basis, which brings evidence on biopsychosocial factors from COVID-19 and the context of the pandemic involved in anxiety and depression disorders.

Differential Outcomes of Infection by Wild-Type SARS-CoV-2 and the B.1.617.2 and B.1.1.529 Variants of Concern in K18-hACE2 Transgenic Mice

BACKGROUND

SARS-CoV-2 is a respiratory virus with neurological complications including the loss of smell and taste, headache, and confusion that can persist for months or longer. Severe neuronal cell damage has also been reported in some cases. The objective of this study was to compare the infectivity of the wild-type virus, Delta (B.1.617.2) and Omicron (B.1.1.529) variants in transgenic mice that express the human angiotensin-converting enzyme 2 (hACE2) receptor under the control of the keratin 18 promoter (K18) and characterize the progression of infection and inflammatory response in the lungs, brain, medulla oblongata, and olfactory bulbs of these animals. We hypothesized that wild type, Delta and Omicron differentially infect K18-hACE2 mice, thereby inducing distinct cellular responses.

METHODS

K18-hACE2 female mice were intranasally infected with wild-type, Delta, or Omicron variants and euthanized either at 3 days post-infection (dpi) or at the humane endpoint. None of the animals infected with the Omicron variant reached the humane endpoint and were euthanized at day 8 dpi. Virological and immunological analyses were performed in the lungs, brains, medulla oblongata and olfactory bulbs isolated from infected mice.

RESULTS

At 3 dpi, mice infected with wild type and Delta displayed significantly higher levels of viral RNA in the lungs than mice infected with Omicron, while in the brain, Delta and Omicron resulted in higher levels of viral RNA than with the wild type. Viral RNA was also detected in the medulla oblongata of mice infected by all these virus strains. At this time point, the mice infected with wild type and Delta displayed a marked upregulation of many inflammatory markers in the lungs. On the other hand, the upregulation of inflammatory markers was observed only in the brains of mice infected with Delta and Omicron. At the humane endpoint, we observed a significant increase in the levels of viral RNA in the lungs and brains of mice infected with wild type and Delta, which was accompanied by the elevated expression of many inflammatory markers. In contrast, mice which survived infection with the Omicron variant showed high levels of viral RNA and the upregulation of cytokine and chemokine expression only in the lungs at 8 dpi, suggesting that infection and inflammatory response by this variant is attenuated in the brain. Reduced RNA levels and the downregulation of inflammatory markers was also observed in the medulla oblongata and olfactory bulbs of mice infected with Omicron at 8 dpi as compared with mice infected with wild-type and Delta at the humane end point. Collectively, these data demonstrate that wild-type, Delta, and Omicron SARS-CoV-2 induce distinct levels of infection and inflammatory responses in K18-hACE2 mice. Notably, sustained brain infection accompanied by the upregulation of inflammatory markers is a critical outcome in mice infected with wild type and Delta but not Omicron.

Cerebrospinal fluid cytokines in COVID-19: a review and meta-analysis

INTRODUCTION

Neurological involvement can occur in patients with SARS-CoV-2 infections, resulting in coronavirus disease 2019 (COVID-19). Cytokine alterations are associated with neurological symptoms in COVID-19. We performed a review of cytokines in the cerebrospinal fluid (CSF) of patients with COVID-19.

METHODS

Two reviewers independently searched PubMed for all relevant articles published prior to November 11, 2022. Active SARS-CoV-2 infection and CSF cytokine analyses were required for inclusion.

RESULTS

Three-hundred forty-six patients with COVID-19 and 356 controls from 28 studies were included. SARS-CoV-2 PCR was positive in the CSF of 0.9% (3/337) of patients with COVID-19. Thirty-seven different cytokines were elevated in the CSF of patients with COVID-19 when compared to controls and the standards set forth by individual assays used in each study. Of the 37 cytokines, IL-6 and IL-8 were most commonly elevated. CSF IL-6 is elevated in 60%, and CSF IL-8 is elevated in 51% of patients with COVID-19.

CONCLUSION

Levels of several inflammatory cytokines are elevated in the CSF of patients with COVID-19, and SARS-CoV-2 PCR is often not isolated in the CSF of patients with COVID-19. Many patients with COVID-19 have neurological symptoms and given the cytokine elevations in the absence of detectable viral RNA in cerebrospinal fluid; further study of the CSF cytokine profiles and pathogenesis of neurological symptoms in COVID-19 is needed.

Recombinant SARS-CoV-2 Spike Protein and Its Receptor Binding Domain Stimulate Release of Different Pro-Inflammatory Mediators via Activation of Distinct Receptors on Human Microglia Cells

SARS-CoV-2 infects cells via its spike (S) protein binding to its surface receptor angiotensin converting enzyme 2 (ACE2) on target cells and results in acute symptoms involving especially the lungs known as COVID-19. However, increasing evidence indicates that SARS-CoV-2 infection produces neuroinflammation associated with neurological, neuropsychiatric, and cognitive symptoms persists well past the resolution of the infection, known as post-COVID-19 sequalae or long-COVID. The neuroimmune mechanism(s) involved in long-COVID have not been adequately characterized. In this study, we show that recombinant SARS-CoV-2 full-length S protein stimulates release of pro-inflammatory IL-1b, CXCL8, IL-6, and MMP-9 from cultured human microglia via TLR4 receptor activation. Instead, recombinant receptor-binding domain (RBD) stimulates release of TNF-α, IL-18, and S100B via ACE2 signaling. These results provide evidence that SARS-CoV-2 spike protein contributes to neuroinflammation through different mechanisms that may be involved in CNS pathologies associated with long-COVID.

Neurological manifestations of post-acute sequelae of COVID-19: which liquid biomarker should we use?

Long COVID syndrome, also known as post-acute sequelae of COVID-19 (PASC), is characterized by persistent symptoms lasting 3-12 weeks post SARS-CoV-2 infection. Patients suffering from PASC can display a myriad of symptoms that greatly diminish quality of life, the most frequent being neuropsychiatric. Thus, there is an eminent need to diagnose and treat PASC related neuropsychiatric manifestation (neuro-PASC). Evidence suggests that liquid biomarkers could potentially be used in the diagnosis and monitoring of patients. Undoubtedly, such biomarkers would greatly benefit clinicians in the management of patients; however, it remains unclear if these can be reliably used in this context. In this mini review, we highlight promising liquid (blood and cerebrospinal fluid) biomarkers, namely, neuronal injury biomarkers NfL, GFAP, and tau proteins as well as neuroinflammatory biomarkers IL-6, IL-10, TNF-α, and CPR associated with neuro-PASC and discuss their limitations in clinical applicability.

Cardiovascular and Neurological Complications of COVID-19: A Narrative Review

A novel coronavirus emerged in China in late 2019 as a disease named coronavirus disease 2019. This pathogen was initially identified as causing a respiratory syndrome, but later, it was found that COVID-19 could also affect other body systems, such as the neurological and cardiovascular systems. For didactic purposes, cardiovascular and neurological manifestations of SARS-CoV-2 have been classified in three different groups: acute complications, late complications, and post-vaccine complications. Therefore, the following study has the goal to summarize and disseminate the present knowledge about the cardiovascular and neurological manifestations of COVID-19 based on the latest and most up-to-date data available and, thus, promote more prepared medical care for these conditions as the medical team is updated. Based on what is brought on this revision and its understanding, the medical service becomes more aware of the causal relationship between some conditions and COVID-19 and can better prepare for the most prevalent conditions to associate and, consequently, to treat patients earlier. Therefore, there is a chance of better prognoses in this context and the need to increase the number of studies about complications related to SARS-CoV-2 infection for a better understanding of other associated conditions.

Human brain organoids to explore SARS-CoV-2-induced effects on the central nervous system

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). In less than three years, an estimated 600 million infections with SARS-CoV-2 occurred worldwide, resulting in a pandemic with tremendous impact especially on economic and health sectors. Initially considered a respiratory disease, COVID-19, along with its long-term sequelae (long-COVID) rather is a systemic disease. Neurological symptoms like dementia or encephalopathy were reported early during the pandemic as concomitants of the acute phase and as characteristics of long-COVID. An excessive inflammatory immune response is hypothesized to play a major role in this context. However, direct infection of neural cells may also contribute to the neurological aspects of (long)-COVID-19. To mainly explore such direct effects of SARS-CoV-2 on the central nervous system, human brain organoids provide a useful platform. Infecting these three-dimensional tissue cultures allows the study of viral neurotropism as well as of virus-induced effects on single cells or even the complex cellular network within the organoid. In this review, we summarize the experimental studies that used SARS-CoV-2-infected human brain organoids to unravel the complex nature of (long)-COVID-19-related neurological manifestations.

Role of SARS-CoV-2 Spike-Protein-Induced Activation of Microglia and Mast Cells in the Pathogenesis of Neuro-COVID

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). About 45% of COVID-19 patients experience several symptoms a few months after the initial infection and develop post-acute sequelae of SARS-CoV-2 (PASC), referred to as "Long-COVID," characterized by persistent physical and mental fatigue. However, the exact pathogenetic mechanisms affecting the brain are still not well-understood. There is increasing evidence of neurovascular inflammation in the brain. However, the precise role of the neuroinflammatory response that contributes to the disease severity of COVID-19 and long COVID pathogenesis is not clearly understood. Here, we review the reports that the SARS-CoV-2 spike protein can cause blood-brain barrier (BBB) dysfunction and damage neurons either directly, or via activation of brain mast cells and microglia and the release of various neuroinflammatory molecules. Moreover, we provide recent evidence that the novel flavanol eriodictyol is particularly suited for development as an effective treatment alone or together with oleuropein and sulforaphane (ViralProtek®), all of which have potent anti-viral and anti-inflammatory actions.

Atypical myelin oligodendrocyte glycoprotein antibody-associated optic neuritis and acute demyelinating polyneuropathy after SARS-CoV-2 infection: Case report and literature review

Post-infectious immune-mediated neurological complications of Sars-Cov-2 have been increasingly recognized since the novel pandemic emerged. We describe the case of a 74 years-old patient who developed a Myelin Oligodendrocyte Glycoprotein (MOG) antibody-associated unilateral retrobulbar optic neuritis a few weeks after paucisymptomatic COVID-19 disease and, subsequently, after the resolution of the optic neuritis, an acute inflammatory demyelinating polyneuropathy. So far, no cases of these two neurological manifestations have been reported in the same patient. We herein report a case characterized by both manifestations and review the accumulating literature regarding MOG antibody-associated disease following SarsCov-2 infection.

Highlights on molecular targets in the management of COVID-19: Possible role of pharmacogenomics

By the end of 2022, there had been a reduction in new cases and deaths caused by coronavirus disease 2019 (COVID-19). At the same time, new variants of the severe acute respiratory syndrome coronavirus 2 virus were being discovered. Critically ill patients with COVID-19 have been found to have high serum levels of proinflammatory cytokines, especially interleukin (IL)-6. COVID-19-related mortality has been attributed in most cases to the cytokine storm caused by increased levels of inflammatory cytokines. Dexamethasone in low doses and immunomodulators such as IL-6 inhibitors are recommended to overcome the cytokine storm. This current narrative review highlights the place of other therapeutic choices such as proteasome inhibitors, protease inhibitors and nuclear factor kappa B inhibitors in the treatment of patients with COVID-19.

COVID-19-associated monocytic encephalitis (CAME): histological and proteomic evidence from autopsy

Severe neurological symptoms are associated with Coronavirus disease 2019 (COVID-19). However, the morphologic features, pathological nature and their potential mechanisms in patient brains have not been revealed despite evidence of neurotropic infection. In this study, neuropathological damages and infiltrating inflammatory cells were quantitatively evaluated by immunohistochemical staining, ultrastructural examination under electron microscopy, and an image threshold method, in postmortem brains from nine critically ill COVID-19 patients and nine age-matched cadavers of healthy individuals. Differentially expressed proteins were identified by quantitative proteomic assays. Histopathological findings included neurophagocytosis, microglia nodules, satellite phenomena, extensive edema, focal hemorrhage, and infarction, as well as infiltrating mononuclear cells. Immunostaining of COVID-19 brains revealed extensive activation of both microglia and astrocytes, severe damage of the blood-brain barrier (BBB) and various degrees of perivascular infiltration by predominantly CD14+/CD16+/CD141+/CCR7+/CD11c+ monocytes and occasionally CD4+/CD8+ T lymphocytes. Quantitative proteomic assays combined with bioinformatics analysis identified upregulated proteins predominantly involved in immune responses, autophagy and cellular metabolism in COVID-19 patient brains compared with control brains. Proteins involved in brain development, neuroprotection, and extracellular matrix proteins of the basement membrane were downregulated, potentially caused by the activation of transforming growth factor β receptor and vascular endothelial growth factor signaling pathways. Thus, our results define histopathological and molecular profiles of COVID-19-associated monocytic encephalitis (CAME) and suggest potential therapeutic targets.

The relationship between chronic immune response and neurodegenerative damage in long COVID-19

In the past two years, the world has faced the pandemic caused by the severe acute respiratory syndrome 2 coronavirus (SARS-CoV-2), which by August of 2022 has infected around 619 million people and caused the death of 6.55 million individuals globally. Although SARS-CoV-2 mainly affects the respiratory tract level, there are several reports, indicating that other organs such as the heart, kidney, pancreas, and brain can also be damaged. A characteristic observed in blood serum samples of patients suffering COVID-19 disease in moderate and severe stages, is a significant increase in proinflammatory cytokines such as interferon-α (IFN-α), interleukin-1β (IL-1β), interleukin-2 (IL-2), interleukin-6 (IL-6) and interleukin-18 (IL-18), as well as the presence of autoantibodies against interferon-α (IFN-α), interferon-λ (IFN-λ), C-C motif chemokine ligand 26 (CCL26), CXC motif chemokine ligand 12 (CXCL12), family with sequence similarity 19 (chemokine (C-C motif)-like) member A4 (FAM19A4), and C-C motif chemokine ligand 1 (CCL1). Interestingly, it has been described that the chronic cytokinemia is related to alterations of blood-brain barrier (BBB) permeability and induction of neurotoxicity. Furthermore, the generation of autoantibodies affects processes such as neurogenesis, neuronal repair, chemotaxis and the optimal microglia function. These observations support the notion that COVID-19 patients who survived the disease present neurological sequelae and neuropsychiatric disorders. The goal of this review is to explore the relationship between inflammatory and humoral immune markers and the major neurological damage manifested in post-COVID-19 patients.

Frequency and burden of neurological manifestations upon hospital presentation in COVID-19 patients: Findings from a large Brazilian cohort

BACKGROUND

Scientific data regarding the prevalence of COVID-19 neurological manifestations and prognosis in Latin America countries is still lacking. Therefore, the study aims to understand neurological manifestations of SARS-CoV 2 infection and outcomes in the Brazilian population.

METHODS

This study is part of the Brazilian COVID-19 Registry, a multicentric cohort, including data from 37 hospitals. For the present analysis, patients were grouped according to the presence of reported symptoms (i.e., headache; anosmia and ageusia; syncope and dizziness) vs. clinically-diagnosed neurological manifestations (clinically-defined neurological syndrome: neurological signs or diagnoses captured by clinical evaluation) and matched with patients without neurological manifestations by age, sex, number of comorbidities, hospital of admission, and whether or not patients had underlying neurological disease.

RESULTS

From 6,635 hospitalized patients with COVID-19, 30.8% presented reported neurological manifestations, 10.3% were diagnosed with a neurological syndrome and 60.1% did not show any neurological manifestations. In patients with reported symptoms, the most common ones were headache (20.7%), ageusia (11.1%) and anosmia (8.0%). In patients with neurological syndromes, acute encephalopathy was the most common diagnosis (9.7%). In the matched analysis, patients with neurological syndromes presented more cases of septic shock (17.0 vs. 13.0%, p = 0.045), intensive care unit admission (45.3 vs. 38.9%, p = 0.023), and mortality (38.7 vs. 32.6%, p = 0.026; and 39.2 vs. 30.3%, p < 0.001) when compared to controls.

CONCLUSION

COVID-19 in-hospital patients with clinically defined neurological syndromes presented a higher incidence of septic shock, ICU admission and death when compared to controls.

Possible Autoimmune Encephalitis Associated with the Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Successfully Treated with Steroids

We encountered a 55-year-old woman with possible autoimmune encephalitis associated with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant. She was not vaccinated against coronavirus disease 2019 (COVID-19). Consciousness disturbance, myoclonic-like movements and gait disturbance occurred 10 days after the COVID-19 symptom onset. Her neurological symptoms improved two days after methylprednisolone pulse therapy. Cerebrospinal fluid (CSF) was negative for SARS-CoV-2 reverse transcription-polymerase chain reaction, the CSF-to-serum albumin quotient was mildly elevated, and interleukin 6 and 8 levels were normal in serum but mildly elevated in CSF. Omicron variant infection may increase blood-brain barrier permeability and intrathecal inflammation, causing autoimmune encephalitis.

Neurogenesis is disrupted in human hippocampal progenitor cells upon exposure to serum samples from hospitalized COVID-19 patients with neurological symptoms

Coronavirus disease 2019 (COVID-19), represents an enormous new threat to our healthcare system and particularly to the health of older adults. Although the respiratory symptoms of COVID-19 are well recognized, the neurological manifestations, and their underlying cellular and molecular mechanisms, have not been extensively studied yet. Our study is the first one to test the direct effect of serum from hospitalised COVID-19 patients on human hippocampal neurogenesis using a unique in vitro experimental assay with human hippocampal progenitor cells (HPC0A07/03 C). We identify the different molecular pathways activated by serum from COVID-19 patients with and without neurological symptoms (i.e., delirium), and their effects on neuronal proliferation, neurogenesis, and apoptosis. We collected serum sample twice, at time of hospital admission and approximately 5 days after hospitalization. We found that treatment with serum samples from COVID-19 patients with delirium (n = 18) decreased cell proliferation and neurogenesis, and increases apoptosis, when compared with serum samples of sex- and age-matched COVID-19 patients without delirium (n = 18). This effect was due to a higher concentration of interleukin 6 (IL6) in serum samples of patients with delirium (mean ± SD: 229.9 ± 79.1 pg/ml, vs. 32.5 ± 9.5 pg/ml in patients without delirium). Indeed, treatment of cells with an antibody against IL6 prevented the decreased cell proliferation and neurogenesis and the increased apoptosis. Moreover, increased concentration of IL6 in serum samples from delirium patients stimulated the hippocampal cells to produce IL12 and IL13, and treatment with an antibody against IL12 or IL13 also prevented the decreased cell proliferation and neurogenesis, and the increased apoptosis. Interestingly, treatment with the compounds commonly administered to acute COVID-19 patients (the Janus kinase inhibitors, baricitinib, ruxolitinib and tofacitinib) were able to restore normal cell viability, proliferation and neurogenesis by targeting the effects of IL12 and IL13. Overall, our results show that serum from COVID-19 patients with delirium can negatively affect hippocampal-dependent neurogenic processes, and that this effect is mediated by IL6-induced production of the downstream inflammatory cytokines IL12 and IL13, which are ultimately responsible for the detrimental cellular outcomes.

Central nervous system (CNS) inflammatory demyelinating diseases (IDDs) associated with COVID-19: A case series and review

BACKGROUND

Over the past two years, SARS-CoV-2 has frequently been documented with various post and para-infectious complications, including cerebrovascular, neuromuscular, and some demyelinating conditions such as acute disseminated encephalomyelitis (ADEM). We report two rare neurological manifestations post-COVID-19 infection; multiple sclerosis (MS) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Further, we reviewed other CNS inflammatory demyelinating diseases (IDDs) associated with SARS-CoV-2, including optic neuritis (ON) and neuromyelitis optica spectrum disorders (NMOSD).

METHODS

A descriptive analysis and literature search of Google Scholar and PubMed was conducted by two independent reviewers from December 1st, 2019, to March 30th, 2022, and included all the case studies of MS, MOGAD, NMOSD, and ON associated with COVID-19 infection.

CASE PRESENTATIONS

Case 1 (MS) was a 24-year-old female with paresthesia and bilateral weakness one week after COVID-19 symptom onset who showed demyelinating plaques and 12 isolated oligoclonal bands (OCBs). Case 2 (MOGAD) was a 41-year-old male with encephalomyelitis 16 days after COVID-19, who later developed MOG-antibody-associated optic neuritis.

RESULTS

Out of 18 cases, NMOSD was the most common post-COVID manifestation (7, 39%), followed by MOGAD (5, 28%), MS (4, 22%), and isolated ON (2, 11%). The median duration between the onset of COVID-19 symptom onset and neurological symptoms was 14 days. 61% of these were male, with a mean age of 35 years. IVMP was the treatment of choice, and nearly all patients made a full recovery, with zero fatalities.

CONCLUSIONS

Although these neurological sequelae are few, physicians must be cognizant of their underlying pathophysiology and associated clinical and neuro-diagnostic findings when treating COVID-19 patients with atypical presentations.

Autoimmunity and SARS-CoV-2 infection: Unraveling the link in neurological disorders

According to the World Health Organization, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has already infected more than 400 million people and caused over 5 million deaths globally. The infection is associated with a wide spectrum of clinical manifestations, ranging from no signs of illness to severe pathological complications that go beyond the typical respiratory symptoms. On this note, new-onset neurological and neuropsychiatric syndromes have been increasingly reported in a large fraction of COVID-19 patients, thus potentially representing a significant public health threat. Although the underlying pathophysiological mechanisms remain elusive, a growing body of evidence suggests that SARS-CoV-2 infection may trigger an autoimmune response, which could potentially contribute to the establishment and/or exacerbation of neurological disorders in COVID-19 patients. Shedding light on this aspect is urgently needed for the development of effective therapeutic intervention. This review highlights the current knowledge of the immune responses occurring in Neuro-COVID patients and discusses potential immune-mediated mechanisms by which SARS-CoV-2 infection may trigger neurological complications.

CXCL8, CCL2, and CMV Seropositivity as New Prognostic Factors for a Severe COVID-19 Course

The exact pathophysiology of severe COVID-19 is not entirely elucidated, but it has been established that hyperinflammatory responses and cytokine storms play important roles. The aim of this study was to examine CMV status, select chemokines, and complement components in COVID-19, and how concentrations of given molecules differ over time at both molecular and proteomic levels. A total of 210 COVID-19 patients (50 ICU and 160 non-ICU patients) and 80 healthy controls were enrolled in this study. Concentrations of select chemokines (CXCL8, CXCL10, CCL2, CCL3, CCR1) and complement factors (C2, C9, CFD, C4BPA, C5AR1, CR1) were examined at mRNA and protein levels with regard to a COVID-19 course (ICU vs. non-ICU group) and CMV status at different time intervals. We detected several significant differences in chemokines and complement profiles between ICU and non-ICU groups. Pro-inflammatory chemokines and the complement system appeared to greatly contribute to the pathogenesis and development of severe COVID-19. Higher concentrations of CXCL8 and CCL2 in the plasma, with reduced mRNA expression presumably through negative feedback mechanisms, as well as CMV-positive status, correlated with more severe courses of COVID-19. Therefore, CXCL8, CCL2, and CMV seropositivity should be considered as new prognostic factors for severe COVID-19 courses. However, more in-depth research is needed.

Role of aging in Blood-Brain Barrier dysfunction and susceptibility to SARS-CoV-2 infection: impacts on neurological symptoms of COVID-19

COVID-19, which is caused by Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2), has resulted in devastating morbidity and mortality worldwide due to lethal pneumonia and respiratory distress. In addition, the central nervous system (CNS) is well documented to be a target of SARS-CoV-2, and studies detected SARS-CoV-2 in the brain and the cerebrospinal fluid of COVID-19 patients. The blood-brain barrier (BBB) was suggested to be the major route of SARS-CoV-2 infection of the brain. Functionally, the BBB is created by an interactome between endothelial cells, pericytes, astrocytes, microglia, and neurons, which form the neurovascular units (NVU). However, at present, the interactions of SARS-CoV-2 with the NVU and the outcomes of this process are largely unknown. Moreover, age was described as one of the most prominent risk factors for hospitalization and deaths, along with other comorbidities such as diabetes and co-infections. This review will discuss the impact of SARS-CoV-2 on the NVU, the expression profile of SARS-CoV-2 receptors in the different cell types of the CNS and the possible role of aging in the neurological outcomes of COVID-19. A special emphasis will be placed on mitochondrial functions because dysfunctional mitochondria are also a strong inducer of inflammatory reactions and the "cytokine storm" associated with SARS-CoV-2 infection. Finally, we will discuss possible drug therapies to treat neural endothelial function in aged patients, and, thus, alleviate the neurological symptoms associated with COVID-19.

Neurological effects of COVID-19 in infants and children

Neurological manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in children are becoming increasingly apparent as the coronavirus disease (COVID-19) pandemic continues. While children manifest relatively milder features of the disease, accumulating evidence warrants concern that COVID-19 exacts both acute- and long-term effects on the developing central and peripheral nervous systems. This review focuses on the relatively underinvestigated topic of the effects of SARS-CoV-2 on the brain in infancy and childhood, concluding that clinicians should be attentive to both the acute effects and long-term consequences of COVID-19 from a neurological perspective.

The nervous system during COVID-19: Caught in the crossfire. Immunol Rev 2022;311:90-111. [PMID: 35770683 PMCID: PMC9350403 DOI: 10.1111/imr.13114]

SARS‐CoV‐2, the virus that causes coronavirus disease (COVID)‐19, has become a persistent global health threat. Individuals who are symptomatic for COVID‐19 frequently exhibit respiratory illness, which is often accompanied by neurological symptoms of anosmia and fatigue. Mounting clinical data also indicate that many COVID‐19 patients display long‐term neurological disorders postinfection such as cognitive decline, which emphasizes the need to further elucidate the effects of COVID‐19 on the central nervous system. In this review article, we summarize an emerging body of literature describing the impact of SARS‐CoV‐2 infection on central nervous system (CNS) health and highlight important areas of future investigation.

Serum Brain-Derived Neurotrophic Factor (BDNF) in COVID-19 Patients and its Association with the COVID-19 Manifestations

COVID-19 is a systematic disease that frequently implies neurological and non-neurological manifestations, predominantly by inducing hypoxia. Brain-derived neurotrophic factor (BDNF) is a key factor in regulating functions of nervous and respiratory systems and has been strongly related to hypoxia. Therefore, this study planned to investigate BDNF association with the COVID-19 manifestations especially neurological impairments and the infection-induced hypoxia. We enrolled sixty-four COVID-19 patients and twenty-four healthy individuals in this study. Patients were divided into two groups, with and without neurological manifestations, and their serum BDNF levels were measured by enzyme-linked immunosorbent assay (ELISA). COVID-19 patients had significantly lower BDNF levels than healthy individuals (p = 0.023). BDNF levels were significantly lower in patients with neurological manifestations compared to healthy individuals (p = 0.010). However, we did not observe a statistically significant difference in BDNF levels between patients with and without neurological manifestations (p = 0.175). BDNF’s levels were significantly lower in patients with CNS manifestations (p = 0.039) and higher in patients with fever (p = 0.03) and dyspnea (p = 0.006). Secondly, BDNF levels have a significant negative association with oxygen therapy requirement (p = 0.015). These results strongly suggest the critical association between dysregulated BDNF and hypoxia in promoting COVID-19 manifestations, particularly neurological impairments.

Plasma Markers of Neurologic Injury and Inflammation in People With Self-Reported Neurologic Postacute Sequelae of SARS-CoV-2 Infection

BACKGROUND AND OBJECTIVES

The biologic mechanisms underlying neurologic postacute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (PASC) are incompletely understood.

METHODS

We measured markers of neurologic injury (glial fibrillary acidic protein [GFAP], neurofilament light chain [NfL]) and soluble markers of inflammation among a cohort of people with prior confirmed SARS-CoV-2 infection at early and late recovery after the initial illness (defined as less than and greater than 90 days, respectively). The primary clinical outcome was the presence of self-reported CNS PASC symptoms during the late recovery time point. We compared fold changes in marker values between those with and without CNS PASC symptoms using linear mixed-effects models and examined relationships between neurologic and immunologic markers using rank linear correlations.

RESULTS

Of 121 individuals, 52 reported CNS PASC symptoms. During early recovery, those who went on to report CNS PASC symptoms had elevations in GFAP (1.3-fold higher mean ratio, 95% CI 1.04-1.63, p = 0.02), but not NfL (1.06-fold higher mean ratio, 95% CI 0.89-1.26, p = 0.54). During late recovery, neither GFAP nor NfL levels were elevated among those with CNS PASC symptoms. Although absolute levels of NfL did not differ, those who reported CNS PASC symptoms demonstrated a stronger downward trend over time in comparison with those who did not report CNS PASC symptoms (p = 0.041). Those who went on to report CNS PASC also exhibited elevations in interleukin 6 (48% higher during early recovery and 38% higher during late recovery), monocyte chemoattractant protein 1 (19% higher during early recovery), and tumor necrosis factor α (19% higher during early recovery and 13% higher during late recovery). GFAP and NfL correlated with levels of several immune activation markers during early recovery; these correlations were attenuated during late recovery.

DISCUSSION

Self-reported neurologic symptoms present approximately 4 months after SARS-CoV-2 infection are associated with elevations in markers of neurologic injury and inflammation at earlier time points. Some inflammatory pathways seem to be involved months after acute infection. Additional work will be needed to better characterize these processes and to identify interventions to prevent or treat this condition.

CSF Biomarkers in COVID-19 Associated Encephalopathy and Encephalitis Predict Long-Term Outcome

Patients with coronavirus disease 2019 (COVID-19) frequently develop acute encephalopathy and encephalitis, but whether these complications are the result from viral-induced cytokine storm syndrome or anti-neural autoimmunity is still unclear. In this study, we aimed to evaluate the diagnostic and prognostic role of CSF and serum biomarkers of inflammation (a wide array of cytokines, antibodies against neural antigens, and IgG oligoclonal bands), and neuroaxonal damage (14-3-3 protein and neurofilament light [NfL]) in patients with acute COVID-19 and associated neurologic manifestations (neuro-COVID). We prospectively included 60 hospitalized neuro-COVID patients, 25 (42%) of them with encephalopathy and 14 (23%) with encephalitis, and followed them for 18 months. We found that, compared to healthy controls (HC), neuro-COVID patients presented elevated levels of IL-18, IL-6, and IL-8 in both serum and CSF. MCP1 was elevated only in CSF, while IL-10, IL-1RA, IP-10, MIG and NfL were increased only in serum. Patients with COVID-associated encephalitis or encephalopathy had distinct serum and CSF cytokine profiles compared with HC, but no differences were found when both clinical groups were compared to each other. Antibodies against neural antigens were negative in both groups. While the levels of neuroaxonal damage markers, 14-3-3 and NfL, and the proinflammatory cytokines IL-18, IL-1RA and IL-8 significantly associated with acute COVID-19 severity, only the levels of 14-3-3 and NfL in CSF significantly correlated with the degree of neurologic disability in the daily activities at 18 months follow-up. Thus, the inflammatory process promoted by SARS-CoV-2 infection might include blood-brain barrier disruption in patients with neurological involvement. In conclusion, the fact that the levels of pro-inflammatory cytokines do not predict the long-term functional outcome suggests that the prognosis is more related to neuronal damage than to the acute neuroinflammatory process.

Old and New Biomarkers for Infection, Inflammation, and Autoimmunity in Treatment-Resistant Affective and Schizophrenic Spectrum Disorders

Affective (AF) and Schizophrenic (SZ) Spectrum disorders manifest with risk factors, involving inflammatory processes linked to infections and autoimmunity. This study searched for novel biomarkers in cerebrospinal fluid (CSF) and peripheral blood. A total of 29 AF and 39 SZ patients with treatment-resistant disease were included. In CSF, the chemokine IL-8 was significantly elevated in AF and SZ patients. IL-8 promotes chemotaxis by neutrophils and may originate from different tissues. S100B, a glia-derived brain damage marker, was higher in CSF from AF than SZ patients. Among the plasma-derived biomarkers, ferritin was elevated in AF and SZ. Soluble CD25, indicating Treg dysfunction, was higher in SZ than in AF patients. Interferon-γ, implying virus-specific immune activation, was positive in selective AF patients, only. Both groups showed elevated expression of immunosuppressive CD33 on monocytes, but higher amounts of CD123+ plasmacytoid dendritic cells were restricted to SZ. In conclusion, chemotactic IL-8 indicates neuronal stress and inflammation in the CSF of both groups. Novel plasma-derived biomarkers such as sCD25 and monocytic CD33 distinguish SZ from AF with an autoimmune phenotype.

Kynurenines in the Pathogenesis of Peripheral Neuropathy During Leprosy and COVID-19

Inflammatory disorders are associated with the activation of tryptophan (TRYP) catabolism via the kynurenine pathway (KP). Several reports have demonstrated the role of KP in the immunopathophysiology of both leprosy and coronavirus disease 19 (COVID-19). The nervous system can be affected in infections caused by both Mycobacterium leprae and SARS-CoV-2, but the mechanisms involved in the peripheral neural damage induced by these infectious agents are not fully understood. In recent years KP has received greater attention due the importance of kynurenine metabolites in infectious diseases, immune dysfunction and nervous system disorders. In this review, we discuss how modulation of the KP may aid in controlling the damage to peripheral nerves and the effects of KP activation on neural damage during leprosy or COVID-19 individually and we speculate its role during co-infection.

Cerebrospinal fluid analysis in patients with COVID-19-associated central nervous system manifestations: a systematic review

ABSTRACT Background: Central nervous system (CNS) symptoms may occur in patients with acute COVID-19. The role of CSF examination in these patients remains to be established. Objective: A systematic review of CSF findings relating to COVID-19 was carried out. Methods: CSF parameters, including cytological and biochemical analyses, SARS-CoV-2 RT-PCR and other CSF markers, were recorded and analyzed among patients with acute COVID-19 and one of the following CNS syndromes: stroke, encephalopathy, encephalitis, inflammatory syndromes, seizure, headache and meningitis. Results: Increased white blood cells and/or increased protein concentration were found in 52.7% of the patients with encephalitis, 29.4% of the patients with encephalopathy and 46.7% of the patients with inflammatory syndromes (P < 0.05). CSF RT-PCR for SARS-CoV-2 was positive in 17.35% of the patients with encephalitis and less than 3.5% of the patients with encephalopathy or inflammatory syndromes (P < 0.05). Intrathecal production of immunoglobulins was found in only 8% of the cases. More than 85% of the patients had increased CSF cytokines and chemokines. Increased CSF neurofilament light chain (NfL) and CSF Tau were found in 71% and 36% of the cases, respectively. Conclusion: Non-specific inflammatory CSF abnormalities were frequently found in patients with COVID-19 CNS syndromes. The increase in neurodegeneration biomarkers suggests that neuronal damage occurs, with long-term consequences that are still unknown.

Neuro-COVID-19

Neuromuscular manifestations of new coronavirus disease 2019 (COVID-19) infection are frequent, and include dizziness, headache, myopathy, and olfactory and gustatory disturbances. Patients with acute central nervous system disorders, such as delirium, impaired consciousness, stroke and convulsive seizures, have a high mortality rate. The encephalitis/encephalopathy that causes consciousness disturbance and seizures can be classified into three conditions, including direct infection with the SARS-CoV-2 virus, encephalopathy caused by central nervous system damage secondary to systemic hypercytokinemia (cytokine storm) and autoimmune-mediated encephalitis that occurs after infection. The sequelae, called post-acute COVID-19 syndrome or long COVID, include neuromuscular manifestations, such as anxiety, depression, sleep disturbance, muscle weakness, brain fog and cognitive impairment. It is desirable to establish diagnostic criteria and treatment for these symptoms. Vaccine-induced thrombotic thrombocytopenia, Guillain-Barré syndrome, bilateral facial paralysis, encephalitis and opsoclonus-myoclonus syndrome have been reported as adverse reactions after the COVID-19 vaccine, although these are rare.

Could SARS-CoV-2 Spike Protein Be Responsible for Long-COVID Syndrome?

SARS-CoV-2 infects cells via its spike protein binding to its surface receptor on target cells and results in acute symptoms involving especially the lungs known as COVID-19. However, increasing evidence indicates that many patients develop a chronic condition characterized by fatigue and neuropsychiatric symptoms, termed long-COVID. Most of the vaccines produced so far for COVID-19 direct mammalian cells via either mRNA or an adenovirus vector to express the spike protein, or administer recombinant spike protein, which is recognized by the immune system leading to the production of neutralizing antibodies. Recent publications provide new findings that may help decipher the pathogenesis of long-COVID. One paper reported perivascular inflammation in brains of deceased patients with COVID-19, while others showed that the spike protein could damage the endothelium in an animal model, that it could disrupt an in vitro model of the blood-brain barrier (BBB), and that it can cross the BBB resulting in perivascular inflammation. Moreover, the spike protein appears to share antigenic epitopes with human molecular chaperons resulting in autoimmunity and can activate toll-like receptors (TLRs), leading to release of inflammatory cytokines. Moreover, some antibodies produced against the spike protein may not be neutralizing, but may change its conformation rendering it more likely to bind to its receptor. As a result, one wonders whether the spike protein entering the brain or being expressed by brain cells could activate microglia, alone or together with inflammatory cytokines, since protective antibodies could not cross the BBB, leading to neuro-inflammation and contributing to long-COVID. Hence, there is urgent need to better understand the neurotoxic effects of the spike protein and to consider possible interventions to mitigate spike protein-related detrimental effects to the brain, possibly via use of small natural molecules, especially the flavonoids luteolin and quercetin.

The Infected Lungs and Brain Interface in COVID-19: The Impact on Cognitive Function

Many coronavirus disease 2019 (COVID-19)-recovered patients report signs and symptoms and are experiencing neurological, psychiatric, and cognitive problems. However, the exact prevalence and outcome of cognitive sequelae is unclear. Even though the severe acute respiratory syndrome coronavirus 2 has target brain cells through binding to angiotensin-converting enzyme 2 (ACE2) receptor in acute infection, several studies indicate the absence of the virus in the brain of many COVID-19 patients who developed neurological disorders. Thus, the COVID-19 mechanisms for stimulating cognitive dysfunction may include neuroinflammation, which is mediated by a sustained systemic inflammation, a disrupted brain barrier, and severe glial reactiveness, especially within the limbic system. This review explores the interplay of infected lungs and brain in COVID-19 and its impact on the cognitive function.

Delirium in Critically Ill Cancer Patients With COVID-19

BACKGROUND

COVID-19 has been a devastating pandemic with little known of its neuropsychiatric complications. Delirium is one of the most common neuropsychiatric syndromes among hospitalized cancer patients with incidence ranging from 25% to 40% and rates of up to 85% in the terminally ill. Data on the incidence, risk factors, duration, and outcomes of delirium in critically ill cancer patients with COVID-19 are lacking.

OBJECTIVE

To report the incidence, risks and outcomes of critically ill cancer patients who developed COVID-19.

METHODS

This is a retrospective single-center study evaluating delirium frequency and outcomes in all critically ill cancer patients with COVID-19 admitted between March 1 and July 10, 2020. Delirium was assessed by Confusion Assessment Method for Intensive Care Unit, performed twice daily by trained intensive care unit (ICU) nursing staff. Patients were considered to have a delirium-positive day if Confusion Assessment Method for Intensive Care Unit was positive at least once per day.

RESULTS

A total of 70 patients were evaluated. Of those 70, 53 (75.7%) were found to be positive for delirium. Patients with delirium were significantly older than patients without delirium (median age 67.5 vs 60.3 y, P = 0.013). There were no significant differences in demographic characteristics, chronic medical conditions, neuropsychiatric history, cancer type, or application of prone positioning between the 2 groups. Delirium patients were less likely to receive cancer-directed therapies (58.5% vs 88.2%, P = 0.038) but more likely to receive antipsychotics (81.1% vs 41.2%, P = 0.004), dexmedetomidine (79.3% vs 11.8%, P < 0.001), steroids (84.9% vs 58.8%, P = 0.039), and vasopressors (90.6% vs 58.8%, P = 0.006). Delirium patients were more likely to be intubated (86.8% vs 41.2%, P < 0.001), and all tracheostomies (35.9%) occurred in patients with delirium. ICU length of stay (19 vs 8 d, P < 0.001) and hospital length of stay (37 vs 12 d, P < 0.001) were significantly longer in delirium patients, but there was no statistically significant difference in hospital mortality (43.4% vs 58.8%, P = 0.403) or ICU mortality (34.0% vs 58.8%, P = 0.090).

CONCLUSIONS

Delirium in critically ill cancer patients with COVID-19 was associated with less cancer-directed therapies and increased hospital and ICU length of stay. However, the presence of delirium was not associated with an increase in hospital or ICU mortality.

Neurologic complications of coronavirus and other respiratory viral infections

In humans, several respiratory viruses can have neurologic implications affecting both central and peripheral nervous system. Neurologic manifestations can be linked to viral neurotropism and/or indirect effects of the infection due to endothelitis with vascular damage and ischemia, hypercoagulation state with thrombosis and hemorrhages, systemic inflammatory response, autoimmune reactions, and other damages. Among these respiratory viruses, recent and huge attention has been given to the coronaviruses, especially the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic started in 2020. Besides the common respiratory symptoms and the lung tropism of SARS-CoV-2 (COVID-19), neurologic manifestations are not rare and often present in the severe forms of the infection. The most common acute and subacute symptoms and signs include headache, fatigue, myalgia, anosmia, ageusia, sleep disturbances, whereas clinical syndromes include mainly encephalopathy, ischemic stroke, seizures, and autoimmune peripheral neuropathies. Although the pathogenetic mechanisms of COVID-19 in the various acute neurologic manifestations are partially understood, little is known about long-term consequences of the infection. These consequences concern both the so-called long-COVID (characterized by the persistence of neurological manifestations after the resolution of the acute viral phase), and the onset of new neurological symptoms that may be linked to the previous infection.

Acute and chronic neurological disorders in COVID-19: potential mechanisms of disease

Coronavirus disease 2019 (COVID-19) is a global pandemic caused by SARS-CoV-2 infection and is associated with both acute and chronic disorders affecting the nervous system. Acute neurological disorders affecting patients with COVID-19 range widely from anosmia, stroke, encephalopathy/encephalitis, and seizures to Guillain-Barré syndrome. Chronic neurological sequelae are less well defined although exercise intolerance, dysautonomia, pain, as well as neurocognitive and psychiatric dysfunctions are commonly reported. Molecular analyses of CSF and neuropathological studies highlight both vascular and immunologic perturbations. Low levels of viral RNA have been detected in the brains of few acutely ill individuals. Potential pathogenic mechanisms in the acute phase include coagulopathies with associated cerebral hypoxic-ischaemic injury, blood-brain barrier abnormalities with endotheliopathy and possibly viral neuroinvasion accompanied by neuro-immune responses. Established diagnostic tools are limited by a lack of clearly defined COVID-19 specific neurological syndromes. Future interventions will require delineation of specific neurological syndromes, diagnostic algorithm development and uncovering the underlying disease mechanisms that will guide effective therapies.

Severe and long-lasting neuropsychiatric symptoms after mild respiratory symptoms caused by COVID-19: A case report

Background

Coronavirus disease 2019 (COVID‐19) is known to cause not only respiratory but also neuropsychiatric symptoms, which are assumed to be derived from a cytokine storm and its effects on the central nervous systems. Patients with COVID‐19 who develop severe respiratory symptoms are known to show severe neuropsychiatric symptoms such as cerebrovascular disease and encephalopathy. However, the detailed clinical courses of patients with neuropsychiatric symptoms caused by mild or asymptomatic COVID‐19 remain poorly understood. Here, we present a case of COVID‐19 who presented with severe and prolonged neuropsychiatric symptoms subsequent to mild respiratory symptoms.

Case presentation

A 55‐year‐old female with COVID‐19 accompanied by mild respiratory symptoms showed delusion, psychomotor excitement, and poor communication ability during quarantine outside the hospital. Considering her diminished respiratory symptoms, her neuropsychiatric symptoms were initially regarded as psychogenic reactions. However, as she showed progressive disturbance of consciousness accompanied by an abnormal electroencephalogram, she was diagnosed with post‐COVID‐19 encephalopathy. Although her impaired consciousness and elevated cytokine level improved after steroid pulse therapy, several neuropsychiatric symptoms, including a loss of concentration, unsteadiness while walking, and fatigue, remained.

Conclusions

This case suggests the importance of both recognizing that even apparently mild COVID‐19‐related respiratory symptoms can lead to severe and persistent neuropsychiatric symptoms, and elucidating the mechanisms, treatment, and long‐term course of COVID‐19‐related neuropsychiatric symptoms in the future.

A 55‐year‐old female with COVID‐19 accompanied by mild respiratory symptoms was diagnosed with post‐COVID‐19 encephalopathy. Although her impaired consciousness and elevated cytokine level improved after steroid pulse therapy, several neuropsychiatric symptoms remained. This case suggests the importance of both recognizing that even apparently mild COVID‐19‐related respiratory symptoms can lead to severe and persistent neuropsychiatric symptoms.

Neuropsychiatric disorders: An immunological perspective

Neuropsychiatric diseases have traditionally been studied from brain, and mind-centric perspectives. However, mounting epidemiological and clinical evidence shows a strong correlation of neuropsychiatric manifestations with immune system activation, suggesting a likely mechanistic interaction between the immune and nervous systems in mediating neuropsychiatric disease. Indeed, immune mediators such as cytokines, antibodies, and complement proteins have been shown to affect various cellular members of the central nervous system in multitudinous ways, such as by modulating neuronal firing rates, inducing cellular apoptosis, or triggering synaptic pruning. These observations have in turn led to the exciting development of clinical therapies aiming to harness this neuro-immune interaction for the treatment of neuropsychiatric disease and symptoms. Besides the clinic, important theoretical fundamentals can be drawn from the immune system and applied to our understanding of the brain and neuropsychiatric disease. These new frameworks could lead to novel insights in the field and further potentiate the development of future therapies to treat neuropsychiatric disease.

Clinical and Radiological Deterioration in a Case of Creutzfeldt-Jakob Disease following SARS-CoV-2 Infection: Hints to Accelerated Age-Dependent Neurodegeneration

Systemic inflammation and the host immune responses associated with certain viral infections may accelerate the rate of neurodegeneration in patients with Creutzfeldt–Jakob disease (CJD), a rare, transmissible neurodegenerative disease. However, the effects of the newly emerged SARS-CoV-2 infection on the pathogenesis of CJD are unknown. In this study, we describe the case of an elderly female patient with sporadic CJD that exhibited clinical deterioration with the emergence of seizures and radiological neurodegenerative progression following an infection with SARS-CoV-2 and severe COVID-19. Despite efforts to control the progression of the disease, a dismal outcome ensued. This report further evidences the age-dependent neurological effects of SARS-CoV-2 infection and proposes a vulnerability to CJD and increased CJD progression following COVID-19.

Molecular Mechanisms of SARS-CoV-2/COVID-19 Pathogenicity on the Central Nervous System: Bridging Experimental Probes to Clinical Evidence and Therapeutic Interventions

The coronavirus disease 2019 (COVID-19) pandemic, induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has dramatically impacted the global healthcare systems, constantly challenging both research and clinical practice. Although it was initially believed that the SARS-CoV-2 infection is limited merely to the respiratory system, emerging evidence indicates that COVID-19 affects multiple other systems including the central nervous system (CNS). Furthermore, most of the published clinical studies indicate that the confirmed CNS inflammatory manifestations in COVID-19 patients are meningitis, encephalitis, acute necrotizing encephalopathy, acute transverse myelitis, and acute disseminated encephalomyelitis. In addition, the neuroinflammation along with accelerated neurosenescence and susceptible genetic signatures in COVID-19 patients might prime the CNS to neurodegeneration and precipitate the occurrence of neurodegenerative diseases, including Alzheimer's and Parkinson's diseases. Thus, this review provides a critical evaluation and interpretive analysis of existing published preclinical as well as clinical studies on the key molecular mechanisms modulating neuroinflammation and neurodegeneration induced by the SARS-CoV-2. In addition, the essential age- and gender-dependent impacts of SARS-CoV-2 on the CNS of COVID-19 patients are also discussed.

Persistent intrathecal interleukin-8 production in a patient with SARS-CoV-2-related encephalopathy presenting aphasia: a case report

BACKGROUND

Neurological manifestations of coronavirus disease 2019 (COVID-19) are increasingly recognized and include encephalopathy, although direct infection of the brain by SARS-CoV-2 remains controversial. We herein report the clinical course and cytokine profiles of a patient with severe SARS-CoV-2-related encephalopathy presenting aphasia.

CASE PRESENTATION

An 81-year-old man developed acute consciousness disturbance and status epileptics several days after SARS-CoV-2 infection. Following treatment with remdesivir and dexamethasone, his consciousness and epileptic seizures improved; however, amnestic aphasia and agraphia remained. Two months after methylprednisolone pulse and intravenous immunoglobulin, his neurological deficits improved. We found increased levels of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 (MCP-1), but not IL-2 and IL-10 in the serum and cerebrospinal fluid (CSF), and the levels of serum IL-6 and MCP-1 were much higher than those in the CSF. The level of IL-8 in the CSF after immunotherapy was four times higher than that before immunotherapy.

CONCLUSION

The cytokine profile of our patient was similar to that seen in severe SARS-CoV-2-related encephalopathy. We demonstrated (i) that the characteristic aphasia can occur as a focal neurological deficit associated with SARS-CoV-2-related encephalopathy, and (ii) that IL8-mediated central nervous system inflammation follows systemic inflammation in SARS-CoV-2-related encephalopathy and can persist and worsen even after immunotherapy. Monitoring IL-8 in CSF, and long-term corticosteroids may be required for treating SARS-CoV-2-related encephalopathy.

Neurotropism of SARS-CoV-2 and neurological diseases of the central nervous system in COVID-19 patients

The devastating COVID-19 pandemic is caused by the SARS-CoV-2 virus. It primarily affects the lung and induces acute respiratory distress leading to a decrease in oxygen supply to the cells. This lung insufficiency caused by SARS-CoV-2 virus contributes to hypoxia which can affect the brain and other organ systems. The heightened cytokine storm in COVID-19 patients leads to an immune reaction in the vascular endothelial cells that compromise the host defenses against the SARS-CoV-2 virus in various organs. The vascular endothelial cell membrane breach allows access for SARS-CoV-2 to infect multiple tissues and organs. The neurotropism of spike protein in SARS-CoV-2 rendered by furin site insertion may increase neuronal infections. These could result in encephalitis and encephalopathy. The COVID-19 patients suffered severe lung deficiency often showed effects in the brain and neural system. The early symptoms include headache, loss of smell, mental confusion, psychiatric disorders and strokes, and rarely encephalitis, which indicated the vulnerability of the nervous system to SARS-CoV-2. Infection of the brain and peripheral nervous system can lead to the dysfunction of other organs and result in multi-organ failure. This review focuses on discussing the vulnerability of the nervous system based on the pattern of expression of the receptors for the SARS-CoV-2 and the mechanisms of its cell invasion. The SARS-CoV-2 elicited immune response and host immune response evasion are further discussed. Then the effects on the nervous system and its consequences on neuro-sensory functions are discussed. Finally, the emerging information on the overall genetic susceptibility seen in COVID-19 patients and its implications for therapy outlook is discussed.

Neuropsychiatric Disorders and COVID-19: What We Know So Far

SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2) affects the central nervous system (CNS), which is shown in a significant number of patients with neurological events. In this study, an updated literature review was carried out regarding neurological disorders in COVID-19. Neurological symptoms are more common in patients with severe infection according to their respiratory status and divided into three categories: (1) CNS manifestations; (2) cranial and peripheral nervous system manifestations; and (3) skeletal muscle injury manifestations. Patients with pre-existing cerebrovascular disease are at a higher risk of admission to the intensive care unit (ICU) and mortality. The neurological manifestations associated with COVID-19 are of great importance, but when life-threatening abnormal vital signs occur in severely ill COVID-19 patients, neurological problems are usually not considered. It is crucial to search for new treatments for brain damage, as well as for alternative therapies that recover the damaged brain and reduce the inflammatory response and its consequences for other organs. In addition, there is a need to diagnose these manifestations as early as possible to limit long-term consequences. Therefore, much research is needed to explain the involvement of SARS-CoV-2 causing these neurological symptoms because scientists know zero about it.

Post-traumatic Neuroinflammation: Relevance to Pediatrics

Both detrimental and beneficial effects of post-traumatic neuroinflammation have become a major research focus as they offer the potential for immediate as well as delayed targeted reparative therapies. Understanding the complex interactions of central and peripheral immunocompetent cells as well as their mediators on brain injury and recovery is complicated by the temporal, regional, and developmental differences in their response to injuries. Microglia, the brain-resident macrophages, have become central in these investigations as they serve a major surveillance function, have the ability to react swiftly to injury, recruit various cellular and chemical mediators, and monitor the reparative/degenerative processes. In this review we describe selected aspects of this burgeoning literature, describing the critical role of cytokines and chemokines, microglia, advances in neuroimaging, genetics and fractal morphology analysis, our research efforts in this area, and selected aspects of pediatric post-traumatic neuroinflammation.

Cerebrospinal fluid in COVID-19 neurological complications: Neuroaxonal damage, anti-SARS-Cov2 antibodies but no evidence of cytokine storm

OBJECTIVE

To study in cerebrospinal fluid (CSF) of COVID-19 subjects if a "cytokine storm" or neuroinflammation are implicated in pathogenesis of neurological complications.

METHODS

Cross-sectional study of CSF neuroinflammatory profiles from 18 COVID-19 subjects with neurological complications categorized by diagnosis (stroke, encephalopathy, headache) and illness severity. COVID-19 CSF was compared with CSF from healthy, infectious and neuroinflammatory disorders and stroke controls (n = 82). Cytokines (IL-6, TNFα, IFNγ, IL-10, IL-12p70, IL-17A), inflammation and coagulation markers (high-sensitivity-C Reactive Protein [hsCRP], ferritin, fibrinogen, D-dimer, Factor VIII) and neurofilament light chain (NF-L), were quantified. SARS-CoV2 RNA and SARS-CoV2 IgG and IgA antibodies in CSF were tested with RT-PCR and ELISA.

RESULTS

CSF from COVID-19 subjects showed absence of pleocytosis or specific increases in pro-inflammatory markers (IL-6, ferritin, or D-dimer). Although pro-inflammatory cytokines (IL-6, TNFα, IL-12p70) and IL-10 were increased in CSF of stroke COVID-19 subjects, a similar increase was observed in non-COVID-19 stroke subjects. Anti-SARS-CoV2 antibodies in CSF of COVID-19 subjects (77%) were observed despite no evidence of SARS-CoV2 viral RNA. CSF-NF-L was elevated in subjects with stroke and critical COVID-19 as compared to controls and other COVID-19 severity categories. CSF-hsCRP was present in all subjects with critical stages of COVID-19 (7/18) but only in 1/82 controls.

CONCLUSION

The paucity of neuroinflammatory changes in CSF of COVID-19 subjects and lack of SARS-CoV2 RNA do not support the presumed neurovirulence of SARS-CoV2 or neuroinflammation in pathogenesis of neurological complications in COVID-19. The role of CSF SARS-CoV2 IgG antibodies and mechanisms of neuronal damage are still undetermined.

Emerging potential mechanisms and predispositions to the neurological manifestations of COVID-19

A spectrum of neurological disease associated with COVID-19 is becoming increasingly apparent. However, the mechanisms behind these manifestations remain poorly understood, significantly hindering their management. The present review subsequently attempts to address the evolving molecular, cellular and systemic mechanisms of NeuroCOVID, which we have classified as the acute and long-term neurological effects of COVID-19. We place particular emphasis on cerebrovascular, demyelinating and encephalitic presentations, which have been reported. Several mechanisms are presented, especially the involvement of a "cytokine storm". We explore the genetic and demographic factors that may predispose individuals to NeuroCOVID. The increasingly evident long-term neurological effects are also presented, including the impact of the virus on cognition, autonomic function and mental wellbeing, which represent an impending burden on already stretched healthcare services. We subsequently reinforce the need for cautious surveillance, especially for those with predisposing factors, with effective clinical phenotyping, appropriate investigation and, if possible, prompt treatment. This will be imperative to prevent downstream neurological sequelae, including those related to the long COVID phenotypes that are being increasingly recognised.

Interleukin-6 (IL-6) inhibitors as therapeutic agents for coronavirus disease 2019 (COVID-19): A systematic review and meta-analysis

INTRODUCTION

Preliminary studies showed that coronavirus disease 2019 (COVID-19) disrupts body immune system, including dysregulation of cytokine interleukin-6 (IL-6). IL-6 inhibitors agents have been used as treatment options for COVID-19, yet their benefit as therapeutic agents remains unclear.

OBJECTIVE

We performed a systematic review and meta-analysis to synthesize the available evidence on the potential therapeutic effect of IL-6 inhibitor agents for the treatment of COVID-19.

METHODS

Two authors initially screened and reviewed the relevant studies from available databases. The data extracted will be tabulated and analyzed for the outcomes. The primary outcome was mortality. Secondary outcomes included discharge from the hospital, length of stay, and requirement for mechanical ventilation. The quality of each study was assessed using OCEBM ratings.

RESULTS

We reviewed 18 studies with a total of 3303 subjects. Tocilizumab was the most commonly used in the studies (15 studies). Meta-analysis of included studies revealed significant reduction in mortality with tocilizumab and sarilumab (RR = 0.61, 95% CI 0.49-0.76). Other outcomes including hospital discharge (RR = 1.04, 95% CI 0.86-1.24), length of stay (mean difference -1.96 days, 95% CI -4.24 to 0.33) or requirement for mechanical ventilation (RR = 0.68, 95% CI 0.32-1.45) revealed no differences of IL-6 inhibitor agents compared to controls.

CONCLUSIONS

Available evidence suggests that IL-6 inhibitor agents reduce the risk of mortality in COVID-19, especially in severe conditions. Further well-designed trials are needed for assessing its efficacy and safety for COVID-19.

Encephalopathies Associated With Severe COVID-19 Present Neurovascular Unit Alterations Without Evidence for Strong Neuroinflammation

Objective

Coronavirus disease (COVID-19) has been associated with a large variety of neurologic disorders. However, the mechanisms underlying these neurologic complications remain elusive. In this study, we aimed at determining whether neurologic symptoms were caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) direct infection or by either systemic or local proinflammatory mediators.

Methods

In this cross-sectional study, we checked for SARS-CoV-2 RNA by quantitative reverse transcription PCR, SARS-CoV-2–specific antibodies, and 49 cytokines/chemokines/growth factors (by Luminex) in the CSF +/− sera of a cohort of 22 COVID-19 patients with neurologic presentation and 55 neurologic control patients (inflammatory neurologic disorder [IND], noninflammatory neurologic disorder, and MS).

Results

We detected anti–SARS-CoV-2 immunoglobulin G in patients with severe COVID-19 with signs of intrathecal synthesis for some of them. Of the 4 categories of tested patients, the CSF of IND exhibited the highest level of cytokines, chemokines, and growth factors. By contrast, patients with COVID-19 did not present overall upregulation of inflammatory mediators in the CSF. However, patients with severe COVID-19 (intensive care unit patients) exhibited higher concentrations of CCL2, CXCL8, and vascular endothelium growth factor A (VEGF-A) in the CSF than patients with a milder form of COVID-19. In addition, we could show that intrathecal CXCL8 synthesis was linked to an elevated albumin ratio and correlated with the increase of peripheral inflammation (serum hepatocyte growth factor [HGF] and CXCL10).

Conclusions

Our results do not indicate active replication of SARS-CoV-2 in the CSF or signs of massive inflammation in the CSF compartment but highlight a specific impairment of the neurovascular unit linked to intrathecal production of CXCL8.