SARS-CoV-2 invasion of the central nervous: a brief review

Neurological, psychological, psychosocial complications of long-COVID and their management

Since it first appeared, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has had a significant and lasting negative impact on the health and economies of millions of individuals all over the globe. At the level of individual health too, many patients are not recovering fully and experiencing a long-term condition now commonly termed 'long-COVID'. Long-COVID is a collection of symptoms which must last more than 12 weeks following initial COVID infection, and which cannot be adequately explained by alternate diagnoses. The neurological and psychosocial impact of long-COVID is itself now a global health crisis and therefore preventing, diagnosing, and managing these patients is of paramount importance. This review focuses primarily on: neurological functioning deficits; mental health impacts; long-term mood problems; and associated psychosocial issues, among patients suffering from long-COVID with an eye towards the neurological basis of these symptoms. A concise account of the clinical relevance of the neurological and psychosocial impacts of long-COVID, the effects on long-term morbidity, and varied approaches in managing patients with significant chronic neurological symptoms and conditions was extracted from the literature, analysed and reported. A comprehensive account of plausible pathophysiological mechanisms involved in the development of long-COVID, its management, and future research needs have been discussed.

Brain Fog: a Narrative Review of the Most Common Mysterious Cognitive Disorder in COVID-19

It has been more than three years since COVID-19 impacted the lives of millions of people, many of whom suffer from long-term effects known as long-haulers. Notwithstanding multiorgan complaints in long-haulers, signs and symptoms associated with cognitive characteristics commonly known as "brain fog" occur in COVID patients over 50, women, obesity, and asthma at excessive. Brain fog is a set of symptoms that include cognitive impairment, inability to concentrate and multitask, and short-term and long-term memory loss. Of course, brain fog contributes to high levels of anxiety and stress, necessitating an empathetic response to this group of COVID patients. Although the etiology of brain fog in COVID-19 is currently unknown, regarding the mechanisms of pathogenesis, the following hypotheses exist: activation of astrocytes and microglia to release pro-inflammatory cytokines, aggregation of tau protein, and COVID-19 entry in the brain can trigger an autoimmune reaction. There are currently no specific tests to detect brain fog or any specific cognitive rehabilitation methods. However, a healthy lifestyle can help reduce symptoms to some extent, and symptom-based clinical management is also well suited to minimize brain fog side effects in COVID-19 patients. Therefore, this review discusses mechanisms of SARS-CoV-2 pathogenesis that may contribute to brain fog, as well as some approaches to providing therapies that may help COVID-19 patients avoid annoying brain fog symptoms.

SARS-CoV-2 induces blood-brain barrier and choroid plexus barrier impairments and vascular inflammation in mice

The coronavirus disease of 2019 (COVID-19) pandemic has led to more than 700 million confirmed cases and nearly 7 million deaths. Although severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus mainly infects the respiratory system, neurological complications are widely reported in both acute infection and long-COVID cases. Despite the success of vaccines and antiviral treatments, neuroinvasiveness of SARS-CoV-2 remains an important question, which is also centered on the mystery of whether the virus is capable of breaching the barriers into the central nervous system. By studying the K18-hACE2 infection model, we observed clear evidence of microvascular damage and breakdown of the blood-brain barrier (BBB). Mechanistically, SARS-CoV-2 infection caused pericyte damage, tight junction loss, endothelial activation and vascular inflammation, which together drive microvascular injury and BBB impairment. In addition, the blood-cerebrospinal fluid barrier at the choroid plexus was also impaired after infection. Therefore, cerebrovascular and choroid plexus dysfunctions are important aspects of COVID-19 and may contribute to neurological complications both acutely and in long COVID.

Alteration of white matter microstructure in patients with sleep disorders after COVID-19 infection

BACKGROUND

The pathophysiology of coronasomnia remains unclear. This study aimed to investigate changes in white matter (WM) microstructure and inflammatory factors in patients with sleep disorders (SD) characterized by poor sleep quantity, quality, or timing following coronavirus disease 2019 (COVID-19) infection in the acute phase (within one month) and whether these changes could be recovered at 3-month follow-up.

METHODS

29 acute COVID-19 patients with SD (COVID_SD) and 27 acute COVID-19 patients without SD (COVID_NonSD) underwent diffusion tensor imaging (DTI), tested peripheral blood inflammatory cytokines level, and measured Pittsburgh Sleep Quality Index (PSQI), and matched 30 uninfected healthy controls. Analyzed WM abnormalities between groups in acute phase and explored its changes in COVID_SD at 3-month follow-up by using tract-based spatial statistics (TBSS). Correlations between DTI and clinical data were examined using Spearman partial correlation analysis.

RESULTS

Both COVID_SD and COVID_NonSD exhibited widespread WM microstructure abnormalities. The COVID_SD group showed specific WM microstructure changes in right inferior fronto-occipital fasciculus (IFOF) (lower fractional anisotropy [FA]/axial diffusivity [AD] and higher radial diffusivity [RD]) and left corticospinal tract (CST) (higher FA and lower RD) and higher interleukin-1β (IL-1β) compared with COVID_NonSD group. These WM abnormalities and IL-1β levels were correlated PSQI score. After 3 months, the IFOF integrity and IL-1β levels tended to return to normal accompanied by symptom improvement in the COVID_SD relative to baseline.

CONCLUSION

Abnormalities in right IFOF and left CST and elevated IL-1β levels were important neurophenotypes correlated with COVID_SD, which might provide new insights into the pathogenesis of neuroinflammation in SD patients induced by COVID-19.

Long COVID in children and adolescents: prevalence, clinical manifestations, and management strategies

Long coronavirus disease (COVID), also known as postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection, has been defined as signs and symptoms which persist for 4 weeks or even lasting for 6 months after the initial infection. Although the prevalence of long COVID in children is currently unknown, epidemiological investigations have reported cases in pediatric populations. Clinical manifestations of long COVID in children include respiratory symptoms, such as cough and dyspnea, as well as neuropsychiatric and general conditions, including fatigue, headache, and muscle weakness. The pathophysiology of long COVID in children is still being investigated, but potential mechanisms include viral persistence, autoimmunity, and neuroinflammation. Risk factors for long COVID in children are not yet well understood, but studies have suggested that children with a history of severe acute COVID-19 infection or comorbidities may be at increased risk. Evaluation for respiratory symptoms of long COVID in children is essential, including spirometry and imaging studies to assess lung function and any potential damage. Furthermore, long COVID in children has been associated with a higher prevalence of mental health problems than in adults, emphasizing the importance of monitoring and addressing these aspects in pediatric patients. Although our understanding of long COVID in children and adolescents is still evolving, it is clear that the condition can have significant impacts on their health and well-being. The aim of this review is to synthesize the current knowledge on the prevalence, risk factors, and pathophysiology of long COVID in children and adolescents, and to discuss potential management strategies based on existing evidence.

Repeated ethanol exposure and withdrawal alters angiotensin-converting enzyme 2 expression in discrete brain regions: Implications for SARS-CoV-2 neuroinvasion

BACKGROUND

People with alcohol use disorder (AUD) may be at higher risk for COVID-19. Angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) are required for cellular entry by SARS-CoV-2, but information on their expression in specific brain regions after alcohol exposure is limited. We sought to clarify how chronic alcohol exposure affects ACE2 expression in monoaminergic brainstem circuits and other putative SARS-CoV-2 entry points.

METHODS

Brains were examined for ACE2 using immunofluorescence after 4 weeks of chronic intermittent ethanol (CIE) vapor inhalation. We also examined TMPRSS2, Cathepsin L, and ADAM17 by Western blot and RAS pathway mediators and pro-inflammatory markers via RT-qPCR.

RESULTS

ACE2 was increased in most brain regions following CIE including the olfactory bulb (OB), hypothalamus (HT), raphe magnus (RMG), raphe obscurus (ROB), locus coeruleus (LC), and periaqueductal gray (PAG). We also observed increased colocalization of ACE2 with monoaminergic neurons in brainstem nuclei. Moreover, soluble ACE2 (sACE2) was elevated in OB, HT, and LC. The increase in sACE2 in OB and HT was accompanied by upregulation of ADAM17, an ACE2 sheddase, while TMPRSS2 increased in HT and LC. Cathepsin L, an endosomal receptor involved in viral entry, was also increased in OB. Alcohol can increase Angiotensin II, which triggers a pro-inflammatory response that may upregulate ACE2 via activation of RAS pathway receptors AT1R/AT2R. ACE2 then metabolizes Angiotensin II to Angiotensin (1-7) and provokes an anti-inflammatory response via MAS1. Accordingly, we report that AT1R/AT2R mRNA decreased in OB and increased in the LC, while MAS1 mRNA increased in both OB and LC. Other mRNAs for pro-inflammatory markers were also dysregulated in OB, HT, raphe, and LC.

CONCLUSIONS

Our results suggest that alcohol triggers a compensatory upregulation of ACE2 in the brain due to disturbed RAS and may increase the risk or severity of SARS-CoV-2 infection.

Finding positive SARS-CoV-2 RT-PCR in cerebrospinal fluid of two pediatric patients with severe COVID-19: a brief case report

BACKGROUND

There is growing evidence of nervous system involvement and related complaints in children with coronavirus disease 2019 (COVID-19). However, it seems that attempts to track of the virus in the nervous system have so far been unsuccessful.

CASE PRESENTATION

Here we describe two pediatric cases of severe COVID-19 who had positive cerebrospinal fluid (CSF) and nasopharyngeal polymerase chain reaction (PCR) tests for severe acute respiratory syndrome coronavirus disease 2019 (SARS-CoV-2). A 36-month-old girl who presented with fever, diarrhea, mild left ventricular dysfunction and bizarre movements, and a five-month-old boy who presented with fever, watery diarrhea, severe dehydration, mottling, and two episodes of seizure. Their CSF analyses and cultures were normal. They admitted in intensive care unit (ICU) for near four days and discharged after ten days without any complaint.

CONCLUSION

This is one of the first reports of the presence of coronavirus in the central nervous system in COVID-19 pediatric patients, emphasizing the neurotropism and neuroinvasion characteristics of the virus.

Mechanisms of COVID-19-induced cerebellitis

The COVID-19 pandemic caused by SARS-CoV2 has raised several important health concerns, not least increased mortality and morbidity. SARS-CoV2 can infect the central nervous system via hematogenous or transneuronal routes, acting through different receptors including ACE2, DPP4, and neuropilin 1 and cause several issues, including the focus here, cerebellitis. The cerebellum is an essential part of the CNS located adjacent to the brainstem with a complex micro and macroscopic structure. The cerebellum plays several physiological roles, such as coordination, cognition, and executive functioning. Damage to the cerebellum can lead to incoordination and ataxia. In our narrative review, we searched different databases from 2021 to 2022 with the keywords cerebellum and COVID-19; 247 studies were identified and reviewed, focusing on clinical studies and excluding non-clinical studies; 56 studies were finally included for analysis. SARS-CoV2 infection of the cerebellum can be seen to be assessed through many methods such as MRI, PET, CT, postmortem studies, and histological findings. These methodological studies have demonstrated that cerebellar infection with COVID-19 can bring about several sequelae: thrombosis, microbleed, hemorrhage, stroke, autoantibody production, ataxia, and widespread inflammation in the cerebellum. Such central effects are likely to exacerbate the known multiorgan effects of SARS-CoV2 and should also be considered as part of disease prognosis.

Cardiac auscultation predicts mortality in elderly patients admitted for COVID-19

INTRODUCTION

COVID-19 has had a great impact on the elderly population. All admitted patients underwent cardiac auscultation at the Emergency Department. However, to our knowledge, there is no literature that explains the implications of cardiac auscultation at the Emergency Department.

MATERIAL AND METHODS

Data collection from our hospital records. Our cohort consists of 300 admissions with a mean age of 81.6 years and 50.7% men.

RESULTS

Pathological cardiac auscultation at the Emergency Department was a risk factor for in-hospital mortality (RR = 1.9; 95% CI 1.3-2.8), heart failure (RR = 3.2; 95% CI = 1.8-5.6), respiratory failure (RR = 1.8; 95% CI = 1.3-2.5), acute kidney injury (RR = 2.6; 95% CI = 2-3.2), and ICU admission (RR = 3.3; 95% CI = 1.3-8.2). The findings in patients with pathological cardiac auscultation were that oxygen saturation in the Emergency Department, arterial pH, and HCO3^- were significantly lower, and the ALT/GPT, LDH, and lactate determinations were significantly higher, which is compatible and correlates with the fact that the main variable is indeed a risk factor for a more severe clinical course. Among the findings from pathological auscultation, arrhythmic tone/arrhythmia was the most frequent (50%) and a risk factor for in-hospital mortality (RR = 2.3; 95% CI = 1.6-3.4). Logistic regression was performed from a multivariate analysis that showed that the initial ex novo arrhythmia correlated with pathological cardiac auscultation is an independent risk factor for in-hospital mortality.

CONCLUSION

Continuous rhythm monitoring makes it possible to detect ex novo arrhythmias and act proactively, and to offer greater care and attention to these patients who have a higher risk of in-hospital mortality and a worse prognosis. Cardiac auscultation can alert us in order to perform more electrocardiograms in these patients and thus have better monitoring.

SARS-CoV-2 consequences for mental health: Neuroinflammatory pathways linking COVID-19 to anxiety and depression

The coronavirus disease 2019 (COVID-19) pandemic has been linked to an increased prevalence of mental health disorders, particularly anxiety and depression. Moreover, the COVID-19 pandemic has caused stress in people worldwide due to several factors, including fear of infection; social isolation; difficulty in adapting to new routines; lack of coping methods; high exposure to social media, misinformation, and fake reports; economic impact of the measures implemented to slow the contagion and concerns regarding the disease pathogenesis. COVID-19 patients have elevated levels of pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α, and other inflammation-related factors. Furthermore, invasion of the central nervous system by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may potentially contribute to neuroinflammatory alterations in infected individuals. Neuroinflammation, a consequence of psychological stress due to the COVID-19 pandemic, may also play a role in the development of anxiety and depressive symptoms in the general population. Considering that neuroinflammation plays a significant role in the pathophysiology of depression and anxiety, this study investigated the effects of SARS-CoV-2 on mental health and focused on the impact of the COVID-19 pandemic on the neuroinflammatory pathways.

COVID-19 and alcohol use disorder: putative differential gene expression patterns that might be associated with neurological complications

BACKGROUND

Several lines of evidence suggest that SARS-CoV-2 invasion of the central nervous system leads to meningitis and encephalopathy syndromes. Additionally, chronic alcoholics were found to be at a higher risk of developing mental health problems and serious neurological manifestations, if exposed to SARS-CoV-2 infection.

METHODS

Herein, we studied RNA seq data from alcoholics' brain tissue and COVID-19 patient's brain tissue to identify the common differentially expressed genes.

RESULTS

Overlap analysis depicted the expression of seven genes (GHRL, SLN, VGF, IL1RL1, NPTX2, PDYN, and RPRML) that were significantly upregulated in both groups. Along with these, protein-protein interaction analysis revealed 10 other key molecules with strong interactions with the aforementioned genes.

CONCLUSIONS

Taken together with the functional effect of these genes, we suggest a strong molecular link between COVID-19-induced severities and neurological impairment in patients suffering from alcohol abuse disorder. These findings emphasize the importance of identifying chronic alcoholism as a risk factor for developing cognitive and memory impairment in COVID-19 patients.

Dementia Risk among Coronavirus Disease Survivors: A Nationwide Cohort Study in South Korea

We aimed to investigate whether coronavirus disease (COVID-19) survivors were at a higher risk of dementia diagnosis compared to controls at 6 months follow-up. Data pertaining to the period between 1 January and 4 June 2020, were extracted from the National Health Insurance Service (NHIS)-COVID-19 database in South Korea. Data on adults (≥20 years old) with no history of dementia, obtained from the NHIS-COVID-19 database, were included in the study. The endpoint of this study was the development of dementia, which was evaluated from 1 January to 1 December 2020. A total of 306,577 adults were included in the analysis, comprising 7133 COVID-19 survivors and 299,444 individuals in the control group. Among the subjects, new-onset dementia diagnosed in 2020 was recorded in 1.2% (3546 of 306,577). In the covariate-adjusted multivariable Cox regression model, the incidence of dementia among COVID-19 survivors was 1.39-fold higher (hazard ratio: 1.39, 95% confidence interval: 1.05–1.85; p = 0.023) than that in the control group. At approximately 6 months of follow-up, COVID-19 survivors were at a higher risk of dementia compared to other populations in South Korea.