SARS-CoV-2 mediated neuroinflammation and the impact of COVID-19 in neurological disorders

COVID-19 susceptibility, hospitalization and severity and the risk of brain cortical structure: a Mendelian randomization study

BACKGROUND

Observational studies have reported structural changes in the brains of patients with coronavirus disease 2019 (COVID-19); it remains unclear whether these associations are causal.

AIM

We evaluated the causal effects of COVID-19 susceptibility, hospitalization and severity on cortical structures.

DESIGN

Mendelian randomization (MR) study.

METHODS

Data on the different COVID-19 phenotypes were obtained from the latest large-scale genome-wide association study (R7) of the COVID-19 Host Genetics Initiative. Brain structure data, including cortical thickness (TH) and surface area (SA), were obtained from the ENIGMA Consortium. Additionally, we employed the round 5 dataset released in January 2021 as the validation cohort. The inverse-variance weighted (IVW) method was used as the primary analysis in MR. Sensitivity analyses were conducted to evaluate heterogeneity and pleiotropy. We performed enrichment analysis on the MR analyses that passed the sensitivity analysis filtering.

RESULTS

After IVW and sensitivity analyses, we observed causal associations between COVID-19 susceptibility and rostral middle frontal SAw (P = 0.0308, β = -39.1236), cuneus THw (P = 0.0170, β = -0.0121), medial orbitofrontal THw (P = 0.0002, β = 0.0225), postcentral THw (P = 0.0217, β = -0.0106), temporal pole THw (P = 0.0077, β = 0.0359), medial orbitofrontal SAnw (P = 0.0106, β = -24.0397), medial orbitofrontal THnw (P = 0.0007, β = 0.0232), paracentral SAnw (P = 0.0483, β = -20.1442), rostral middle frontal SAnw (P = 0.0368, β = -81.9719) and temporal pole THnw (P = 0.0429, β = 0.0353). COVID-19 hospitalization had causal effects on medial orbitofrontal THw (P = 0.0053, β = 0.0063), postcentral THw (P = 0.0143, β = -0.0042), entorhinal THnw (P = 0.0142, β = 0.0142), medial orbitofrontal THnw (P = 0.0147, β = 0.0065) and paracentral SAnw (P = 0.0119, β = -7.9970). COVID-19 severity had causal effects on rostral middle frontal SAw (P = 0.0122, β = -11.8296), medial orbitofrontal THw (P = 0.0155, β = 0.0038), superior parietal THw (P = 0.0291, β = -0.0021), lingual SAnw (P = 0.0202, β = -11.5270), medial orbitofrontal THnw (P = 0.0290, β = 0.0039), paracentral SAnw (P = 0.0180, β = -5.7744) and pars triangularis SAnw (P = 0.0151, β = -5.4520).

CONCLUSION

Our MR results demonstrate a causal relationship between different COVID-19 phenotypes and cortical structures.

Epidemiology of Parkinson's Disease: An Update

PURPOSE OF REVIEW

In recent decades, epidemiological understanding of Parkinson disease (PD) has evolved significantly. Major discoveries in genetics and large epidemiological investigations have provided a better understanding of the genetic, behavioral, and environmental factors that play a role in the pathogenesis and progression of PD. In this review, we provide an epidemiological update of PD with a particular focus on advances in the last five years of published literature.

RECENT FINDINGS

We include an overview of PD pathophysiology, followed by a detailed discussion of the known distribution of disease and varied determinants of disease. We describe investigations of risk factors for PD, and provide a critical summary of current knowledge, knowledge gaps, and both clinical and research implications. We emphasize the need to characterize the epidemiology of the disease in diverse populations. Despite increasing understanding of PD epidemiology, recent paradigm shifts in the conceptualization of PD as a biological entity will also impact epidemiological research moving forward and guide further work in this field.

Potential convergence of olfactory dysfunction in Parkinson's disease and COVID-19: The role of neuroinflammation

Parkinson's disease (PD) is a prevalent neurodegenerative disorder that affects 7-10 million individuals worldwide. A common early symptom of PD is olfactory dysfunction (OD), and more than 90% of PD patients suffer from OD. Recent studies have highlighted a high incidence of OD in patients with SARS-CoV-2 infection. This review investigates the potential convergence of OD in PD and COVID-19, particularly focusing on the mechanisms by which neuroinflammation contributes to OD and neurological events. Starting from our fundamental understanding of the olfactory bulb, we summarize the clinical features of OD and pathological features of the olfactory bulb from clinical cases and autopsy reports in PD patients. We then examine SARS-CoV-2-induced olfactory bulb neuropathology and OD and emphasize the SARS-CoV-2-induced neuroinflammatory cascades potentially leading to PD manifestations. By activating microglia and astrocytes, as well as facilitating the aggregation of α-synuclein, SARS-CoV-2 could contribute to the onset or exacerbation of PD. We also discuss the possible contributions of NF-κB, the NLRP3 inflammasome, and the JAK/STAT, p38 MAPK, TLR4, IL-6/JAK2/STAT3 and cGAS-STING signaling pathways. Although olfactory dysfunction in patients with COVID-19 may be reversible, it is challenging to restore OD in patients with PD. With the emergence of new SARS-CoV-2 variants and the recurrence of infections, we call for continued attention to the intersection between PD and SARS-CoV-2 infection, especially from the perspective of OD.

Causal effects of gut microbiota on multiple sclerosis: A two-sample Mendelian randomization study

BACKGROUND

Gut microbiota alterations in multiple sclerosis (MS) patients have been reported in observational studies, but whether these associations are causal is unclear.

OBJECTIVE

We performed a Mendelian randomization study (MR) to assess the causal effects of gut microbiota on MS.

METHODS

Independent genetic variants associated with 211 gut microbiota phenotypes were selected as instrumental variables from the largest genome-wide association studies (GWAS) previously published by the MiBioGen study. GWAS data for MS were obtained from the International Multiple Sclerosis Genetics Consortium (IMSGC) for primary analysis and the FinnGen consortium for replication and collaborative analysis. Sensitivity analyses were conducted to evaluate heterogeneity and pleiotropy.

RESULTS

After inverse-variance-weighted and sensitivity analysis filtering, seven gut microbiota with potential causal effects on MS were identified from the IMSGC. Only five metabolites remained significant associations with MS when combined with the FinnGen consortium, including genus Anaerofilum id.2053 (odds ratio [OR] = 1.141, 95% confidence interval [CI]: 1.021-1.276, p = .021), Ruminococcus2 id.11374 (OR = 1.190, 95% CI: 1.007-1.406, p = .042), Ruminococcaceae UCG003 id.11361 (OR = 0.822, 95% CI: 0.688-0.982, p = .031), Ruminiclostridium5 id.11355 (OR = 0.724, 95% CI: 0.585-0.895, p = .003), Anaerotruncus id.2054 (OR = 0.772, 95% CI: 0.634-0.940, p = .010).

CONCLUSION

Our MR analysis reveals a potential causal relationship between gut microbiota and MS, offering promising avenues for advancing mechanistic understanding and clinical investigation of microbiota-mediated MS.

COVID-19 vaccination may prevent postoperative delirium in elderly patients undergoing elective non-cardiac surgery: The PNDRFAP and PNDABLE studies

Background

Postoperative delirium (POD) often occurs in elderly patients after surgery. We conducted two clinical studies to determine whether COVID-19 vaccination has a protective effect on POD and to explore the role of CSF biomarkers in this process.

Methods

We conducted two clinical studies, Perioperative Neurocognitive Disorder Risk Factor and Prognosis (PNDRFAP) and Perioperative Neurocognitive Disorder and Biomarker Lifestyle (PNDABLE), in which patients more than or equal to 65 years old who have had elective non-cardiac surgery were enrolled. The preoperative cognitive status of patients were evaluated by Mini-Mental State Examination (MMSE) one day preoperatively. Confusion Assessment Method (CAM) was used to diagnose POD. We used the mediation model to analyze the relationship between CSF biomarkers, COVID-19 vaccination and POD, as well as Dynamic Nomogram to calculate the incidence of Non-Postoperative Delirium (NPOD). The main outcome of these studies was the incidence of POD during seven days postoperatively or before discharge, which was assessed by CAM.

Results

In the final, 705 participants were enrolled in the PNDRFAP study, and 638 patients in the PNDABLE. In both studies, we found that the occurrence of POD was lower in patients who had injected COVID-19 vaccination before surgery compared with those without vaccination (PNDRFAP: 10.20 % [21/205] vs 25.80 % [129/500], P < 0.001; PNDABLE: 2.40 % [4/164] vs 34.60 % [164/474], P < 0.001). Mediation analysis showed that the protective effect of preoperative COVID-19 vaccine on POD was significantly mediated by CSF Aβ42 (proportion = 17.56 %), T-tau (proportion = 19.64 %), Aβ42/T-tau (proportion = 29.67 %), and Aβ42/P-tau (proportion = 12.26 %).

Conclusions

COVID-19 vaccine is a protective factor for POD in old patients, which is associated with CSF biomarkers.

Exploring the Prevalence of Tinnitus and Ear-Related Symptoms in China After the COVID-19 Pandemic: Online Cross-Sectional Survey

BACKGROUND

Tinnitus is a complex and heterogeneous disease that has been identified as a common manifestation of COVID-19. To gain a comprehensive understanding of tinnitus symptoms in individuals following COVID-19 infection, we conducted an online survey called the China Ear Nose and Throat Symptom Survey in the COVID-19 Pandemic (CENTSS) among the Chinese population.

OBJECTIVE

Our objective was to investigate tinnitus and ear-related symptoms after COVID-19 infection in the Chinese population, with the aim of providing a solid empirical foundation for improved health care. The findings from CENTSS can contribute to the development of enhanced management strategies for tinnitus in the context of long COVID. By gaining a better understanding of the factors contributing to tinnitus in individuals with COVID-19, health care providers can tailor interventions to address the specific needs of affected patients. Furthermore, this study serves as a basis for research on the long-term consequences of COVID-19 infection and its associated tinnitus symptoms.

METHODS

A quantitative, online, cross-sectional survey study design was used to explore the impact of the COVID-19 pandemic on experiences with tinnitus in China. Data were collected through an online questionnaire designed to identify the presence of tinnitus and its impacts. Descriptive statistics were used to analyze individuals' demographic characteristics, COVID-19 infection-related ear symptoms, and the cognitive and emotional implications of tinnitus. Univariable and multivariable logistic regression analyses were used to model the cross-sectional baseline associations between demographic characteristics, noise exposure, educational level, health and lifestyle factors, and the occurrence of tinnitus.

RESULTS

Between December 19, 2022, and February 1, 2023, we obtained responses from 1262 Chinese participants representing 24 regions, with an average age of 37 years. Among them, 540 patients (42.8%) reported experiencing ear-related symptoms after COVID-19 infection. Only 114 (9%) of these patients sought medical attention specifically for their ear symptoms, while 426 (33.8%) did not seek hospital care. Tinnitus emerged as the most prevalent and impactful symptom among all ear-related symptoms experienced after COVID-19 infection. Of the respondents, female participants (688/888, 77.78%), younger individuals (<30 years), individuals with lower education levels, participants residing in western China, and those with a history of otolaryngology diseases were more likely to develop tinnitus following COVID-19 infection.

CONCLUSIONS

In summary, tinnitus was identified as the most common ear-related symptom during COVID-19 infection. Individuals experiencing tinnitus after COVID-19 infection were found to have poorer cognitive and emotional well-being. Different ear-related symptoms in patients post-COVID-19 infection may suggest viral invasion of various parts of the ear. It is therefore crucial to monitor and manage hearing-related changes resulting from COVID-19 as clinical services resume.

Assessing the Burden and Cost of COVID-19 Across Variants in Commercially Insured Immunocompromised Populations in the United States: Updated Results and Trends from the Ongoing EPOCH-US Study

INTRODUCTION/METHODS

EPOCH-US is an ongoing, retrospective, observational cohort study among individuals identified in the Healthcare Integrated Research Database (HIRD®) with ≥ 12 months of continuous health plan enrollment. Data were collected for the HIRD population (containing immunocompetent and immunocompromised [IC] individuals), individual IC cohorts (non-mutually exclusive cohorts based on immunocompromising condition and/or immunosuppressive [IS] treatment), and the composite IC population (all unique IC individuals). This study updates previous results with addition of the general population cohort and data specifically for the year of 2022 (i.e., Omicron wave period). To provide healthcare decision-makers the most recent trends, this study reports incidence rates (IR) and severity of first SARS-CoV-2 infection; and relative risk, healthcare utilization, and costs related to first COVID-19 hospitalizations in the full year of 2022 and overall between April 2020 and December 2022.

RESULTS

These updated results showed a 2.9% prevalence of immune compromise in the population. From April 2020 through December 2022, the overall IR of COVID-19 was 115.7 per 1000 patient-years in the composite IC cohort and 77.8 per 1000 patient-years in the HIRD cohort. The composite IC cohort had a 15.4% hospitalization rate with an average cost of $42,719 for first COVID-19 hospitalization. Comparatively, the HIRD cohort had a 3.7% hospitalization rate with an average cost of $28,848 for first COVID-19 hospitalization. Compared to the general population, IC individuals had 4.3 to 23 times greater risk of hospitalization with first diagnosis of COVID-19. Between January and December 2022, hospitalizations associated with first COVID-19 diagnosis cost over $1 billion, with IC individuals (~ 3% of the population) generating $310 million (31%) of these costs.

CONCLUSION

While only 2.9% of the population, IC individuals had a higher risk of COVID-19 hospitalization and incurred higher healthcare costs across variants. They also disproportionately accounted for over 30% of total costs for first COVID-19 hospitalization in 2022, amounting to ~ $310 million. These data highlight the need for additional preventive measures to decrease the risk of developing severe COVID-19 outcomes in vulnerable IC populations.

Intranasal Versus Intravenous Dexamethasone to Treat Hospitalized COVID-19 Patients: A Randomized Multicenter Clinical Trial

BACKGROUND

SARS-CoV2 induces flu-like symptoms that can rapidly progress to severe acute lung injury and even death. The virus also invades the central nervous system (CNS), causing neuroinflammation and death from central failure. Intravenous (IV) or oral dexamethasone (DXM) reduced 28 d mortality in patients who required supplemental oxygen compared to those who received conventional care alone. Through these routes, DMX fails to reach therapeutic levels in the CNS. In contrast, the intranasal (IN) route produces therapeutic levels of DXM in the CNS, even at low doses, with similar systemic bioavailability.

AIMS

To compare IN vs. IV DXM treatment in hospitalized patients with COVID-19.

METHODS

A controlled, multicenter, open-label trial. Patients with COVID-19 (69) were randomly assigned to receive IN-DXM (0.12 mg/kg for three days, followed by 0.6 mg/kg for up to seven days) or IV-DXM (6 mg/d for 10 d). The primary outcome was clinical improvement, as defined by the National Early Warning Score (NEWS) ordinal scale. The secondary outcome was death at 28 d between IV and IN patients. Effects of both treatments on biochemical and immunoinflammatory profiles were also recorded.

RESULTS

Initially, no significant differences in clinical severity, biometrics, and immunoinflammatory parameters were found between both groups. The NEWS-2 score was reduced, in 23 IN-DXM treated patients, with no significant variations in the 46 IV-DXM treated ones. Ten IV-DXM-treated patients and only one IN-DXM patient died.

CONCLUSIONS

IN-DMX reduced NEWS-2 and mortality more efficiently than IV-DXM, suggesting that IN is a more efficient route of DXM administration.

Older adults with epilepsy and COVID-19: Outcomes in a multi-hospital health system

BACKGROUND

Coronavirus disease 2019 (COVID-19) is associated with high rates of mortality and morbidity in older adults, especially those with pre-existing conditions. There is little work investigating how neurological conditions affect older adults with COVID-19. We aimed to compare in-hospital outcomes, including mortality, in older adults with and without epilepsy.

METHODS

This retrospective study in a large multicenter New York health system included consecutive older patients (age ≥65 years) either with or without epilepsy who were admitted with COVID-19 between 3/2020-5/2021. Epilepsy was identified using a validated International Classification of Disease (ICD) and antiseizure medicationbased case definition. Univariate comparisons were calculated using Chi-square, Fisher's exact, Mann-Whitney U, or Student's t-tests. Multivariable logistic regression models were generated to examine factors associated with mortality, discharge disposition and length of stay (LOS).

RESULTS

We identified 5384 older adults admitted with COVID-19 of whom 173 (3.21 %) had epilepsy. Mean age was significantly lower in those with (75.44, standard deviation (SD): 7.23) compared to those without epilepsy (77.98, SD: 8.68, p = 0.007). Older adults with epilepsy were more likely to be ventilated (35.84 % vs. 16.18 %, p < 0.001), less likely to be discharged home (21.39 % vs. 43.12 %, p < 0.001), had longer median LOS (13 days vs. 8 days, p < 0.001), and had higher in-hospital death (35.84 % vs. 28.29 %, p = 0.030) compared to those without epilepsy. Epilepsy in older adults was associated with increased odds of in-hospital death (adjusted odds ratio (aOR), 1.55; 95 % CI 1.12-2.14, p = 0.032), non-routine discharge disposition (aOR, 3.34; 95 % CI 2.21-5.03, p < 0.001), and longer LOS (46.46 % 95 % CI 34 %-59 %, p < 0.001).

CONCLUSIONS

In models that adjusted for multiple confounders including comorbidity and age, our study found that epilepsy was still associated with higher in-hospital mortality, longer LOS and worse discharge dispositions in older adults with COVID-19 higher in-hospital mortality, longer LOS and worse discharge dispositions in older adults with COVID-19. This work reinforces that epilepsy is a risk factor for worse outcomes in older adults admitted with COVID-19. Timely identification and treatment of COVID-19 in epilepsy may improve outcomes in older people with epilepsy.

Systematical analyses of large-scale transcriptome reveal viral infection-related genes and disease comorbidities

Perturbation of transcriptome in viral infection patients is a recurrent theme impacting symptoms and mortality, yet a detailed understanding of pertinent transcriptome and identification of robust biomarkers is not complete. In this study, we manually collected 23 datasets related to 6,197 blood transcriptomes across 16 types of respiratory virus infections. We applied a comprehensive systems biology approach starting with whole-blood transcriptomes combined with multilevel bioinformatics analyses to characterize the expression, functional pathways, and protein-protein interaction (PPI) networks to identify robust biomarkers and disease comorbidities. Robust gene markers of infection with different viruses were identified, which can accurately classify the normal and infected patients in train and validation cohorts. The biological processes (BP) of different viruses showed great similarity and enriched in infection and immune response pathways. Network-based analyses revealed that a variety of viral infections were associated with nervous system diseases, neoplasms and metabolic diseases, and significantly correlated with brain tissues. In summary, our manually collected transcriptomes and comprehensive analyses reveal key molecular markers and disease comorbidities in the process of viral infection, which could provide a valuable theoretical basis for the prevention of subsequent public health events for respiratory virus infections.

Prenatal SARS-CoV-2 Spike Protein Exposure Induces Autism-Like Neurobehavioral Changes in Male Neonatal Rats

Recent research on placental, embryo, and brain organoids suggests that the COVID-19 virus may potentially affect embryonic organs, including the brain. Given the established link between SARS-CoV-2 spike protein and neuroinflammation, we sought to investigate the effects of exposure to this protein during pregnancy. We divided pregnant rats into three groups: Group 1 received a 1 ml/kg saline solution, Group 2 received 150 μg/kg adjuvant aluminum hydroxide (AAH), and Group 3 received 40 μg/kg spike protein + 150 μg/kg AAH at 10 and 14 days of gestation. On postnatal day 21 (P21), we randomly separated 60 littermates (10 male-female) into control, AAH-exposed, and spike protein-exposed groups. At P50, we conducted behavioral analyses on these mature animals and performed MR spectroscopy. Subsequently, all animals were sacrificed, and their brains were subject to biochemical and histological analysis. Our findings indicate that male rats exposed to the spike protein displayed a higher rate of impaired performance on behavioral studies, including the three-chamber social test, passive avoidance learning analysis, open field test, rotarod test, and novelty-induced cultivation behavior, indicative of autistic symptoms. Exposure to the spike protein (male) induced gliosis and neuronal cell death in the CA1-CA3 regions of the hippocampus and cerebellum. The spike protein-exposed male rats exhibited significantly greater levels of malondialdehyde (MDA), tumor necrosis factor alpha (TNF-α), interleukin-17 (IL-17), nuclear factor kappa B (NF-κB), and lactate and lower levels of brain-derived neurotrophic factor (BDNF) than the control group. Our study suggests a potential association between prenatal exposure to COVID-19 spike protein and neurodevelopmental problems, such as ASD. These findings highlight the importance of further research into the potential effects of the COVID-19 virus on embryonic and fetal development and the potential long-term consequences for neurodevelopment.

The Antidepressant Activity of a Taurine-Containing Derivative of 4-Phenylpyrrolidone-2 in a Model of Chronic Unpredictable Mild Stress

This study investigates the therapeutic potential of a new compound, potassium 2-[2-(2-oxo-4-phenylpyrrolidin-1-yl) acetamido]ethanesulfonate (Compound I), in depression. Willner's chronic unpredictable mild stress model of male Wistar rats was used as a depression model. The rats were randomized into four groups, including an intact group, a Compound I group, a Fluoxetine group, and a control group with saline. Behavioral tests, such as the Porsolt forced swim test, hole-board test, elevated plus maze test, and light-dark box, were used to assess the animals' conditions. Our results demonstrated that Compound I effectively reduced the immobilization time of rats in the forced swim test, increased orientation and exploratory behavior, and decreased the latency period of going into the dark compartment compared to the control group. Hippocampal and striatal serotonin concentrations were increased in the Compound I group, and the compound also reduced the level of corticosterone in the blood plasma of rats compared to the intact animals. These results suggest that Compound I has reliable antidepressant activity, comparable to that of the reference antidepressant Fluoxetine.

Case Report of Improvement in Long-COVID Symptoms in an Air Force Medic Treated With Transcranial Magnetic Stimulation Using Electro-Magnetic Brain Pulse Technique

Long-coronavirus disease (COVID) is an ill-defined set of symptoms persisting in patients following infection with COVID-19 that range from any combination of persistent breathing difficulties to anosmia, impaired attention, memory, fatigue, or pain. Recently, noninvasive transcutaneous electrical brain stimulation techniques have been showing early signs of success in addressing some of these complaints. We postulate that the use of a stimulation technique with transcranial magnetic stimulation may also similarly be effective. A 36-year-old male suffering from symptoms of dyspnea, anosmia, and "brain fog" for 2 years following coronavirus infection was treated with 10 sessions of Electro-Magnetic Brain Pulse (EMBP®), a personalized transcranial magnetic stimulation protocol guided by the patient's electroencephalograph (EEG). At the conclusion of the treatment, the patient had improvements in mood, sense of smell, and brain fogging. Dyspnea also decreased with a gain of 11% forced expiratory volume 1/forced vital capacity. A high-sensitivity athletic training cognitive test showed an overall 27% increase in aggregate score. A significant portion of this was attributed to changes in visual clarity and decision-making speed. Post-treatment EEG showed a shift from predominantly delta waves to more synchronized alpha wave patterns during the resting state. Brain stimulation techniques appear to be showing early signs of success with long-COVID symptoms. This is the first case describing the use of a magnetic stimulation technique with quantitative test results and recorded EEG changes. Given the early success in this patient with cognition, dyspnea, and anosmia, this noninvasive treatment modality warrants further research.

Association between COVID-19 and myasthenia gravis (MG): A genetic correlation and Mendelian randomization study

BACKGROUND

Observational studies have suggested an association between coronavirus disease 2019 (COVID-19) and myasthenia gravis (MG). Here, we aimed to estimate the genetic correlation and causal relationship between COVID-19 susceptibility, hospitalization, severity, and MG phenotypes using linkage disequilibrium score regression (LDSC) and Mendelian randomization (MR) approach.

METHODS

Summary statistics of COVID-19 susceptibility, hospitalization, and severity were used as instrumental variables for exposure traits. Large-scale genome-wide association study (GWAS) data for MG were used as outcome traits. The inverse variance weighted approach was used for the main MR analysis, complemented by MR-Egger, weighted median, simple mode, and weighted mode methods. Sensitivity analysis was implemented using Cochran's Q test, MR-PRESSO method, and MR-Egger intercept test.

RESULTS

LDSC analysis did not reveal any genetic correlation among COVID-19 susceptibility, hospitalization, severity, and MG phenotypes, including MG, early-onset MG, and late-onset MG (p > .05). Our MR analysis did not provide evidence supporting a causal effect of COVID-19 susceptibility, hospitalization, or severity on MG phenotypes (p > .05). Extensive sensitivity analysis strengthened the robustness and consistency of the MR estimates.

CONCLUSION

Our study did not find evidence of a genetic correlation or causal relationship among COVID-19 susceptibility, hospitalization, severity, and MG. Future studies with more GWAS data are needed to evaluate the association between COVID-19 phenotypes and MG and its subgroups.

Targeting Viral ORF3a Protein: A New Approach to Mitigate COVID-19 Induced Immune Cell Apoptosis and Associated Respiratory Complications

Infection with SARS-CoV-2 is a growing concern to the global well-being of the public at present. Different amino acid mutations alter the biological and epidemiological characteristics, as well as immune resistance of SARS-CoV-2. The virus-induced pulmonary impairment and inflammatory cytokine storm are directly related to its clinical manifestations. But, the fundamental mechanisms of inflammatory responses are found to be the reason for the death of immune cells which render the host immune system failure. Apoptosis of immune cells is one of the most common forms of programmed cell death induced by the virus for its survival and virulence property. ORF3a, a SARS-CoV-2 accessory viral protein, induces apoptosis in host cells and suppress the defense mechanism. This suggests, inhibiting SARS-CoV-2 ORF3a protein is a good therapeutic strategy for the treatment in COVID-19 infection by promoting the host immune defense mechanism.

Post-COVID-19 fatigue and health-related quality of life in Saudi Arabia: a population-based study

Background

Despite substantial literature on symptoms and long-term health implications associated with COVID-19; prevalence and determinants of post-acute COVID-19 fatigue (PCF) remain largely elusive and understudied, with scant research documenting health-related quality of life (HRQoL). Hence, prevalence of PCF and its associated factors, and HRQoL among those who have survived Covid-19 within the general population of Saudi Arabia (KSA) is the subject under examination in this research.

Methods

This cross-sectional study was conducted on 2063 individuals, selected from the KSA's general population, using a non-probability sampling approach. An online survey was used to employ a self-administered questionnaire to the participants, which included socio-demographic information, the patient's COVID-19 infection history, 12-item Short Form Health Survey (SF-12) to assess quality of life, and Chalder Fatigue Scale (CFS) (CFQ 11) to evaluate the extent and severity of fatigue. Data were analyzed using SPSS version 26. A p < 0.05 was considered to be strong evidence against the null hypothesis.

Results

The median age of participants was 34 (IQR = 22) years, with females comprising the majority (66.2%). According to the SF-12 questionnaire, 91.2% of patients experienced physical conditions, and 77% experienced depression. The prevalence of PCF was 52% on CFQ 11 scale. Female gender, higher levels of education, a pre-existing history of chronic disease, as well as the manifestations of shortness of breath and confusion during acute COVID-19 infection, were identified as independent predictors of fatigue.

Conclusion

To facilitate timely and effective intervention for post-acute COVID-19 fatigue, it is essential to continuously monitor the individuals who have recovered from acute COVID-19 infection. Also, it is critical to raise health-education among these patients to improve their quality of life. Future research is required to determine whether COVID-19 survivors would experience fatigue for an extended duration and the impact of existing interventions on its prevalence and severity.

Preventing and treating delirium in clinical settings for older adults

Delirium is a serious consequence of many acute or worsening chronic medical conditions, a side effect of medications, and a precipitant of worsening functional and cognitive status in older adults. It is a syndrome characterized by fluctuations in cognition and impaired attention that develops over a short period of time in response to an underlying medical condition, a substance (prescribed, over the counter, or recreational), or substance withdrawal and can be multi-factorial. We present a narrative review of the literature on nonpharmacologic and pharmacologic approaches to prevention and treatment of delirium with a focus on older adults as a vulnerable population. Older adult patients are most at risk due to decreasing physiologic reserves, with delirium rates of up to 80% in critical care settings. Presentation of delirium can be hyperactive, hypoactive, or mixed, making identification and study challenging as patients with hypoactive delirium are less likely to come to attention in an inpatient or long-term care setting. Studies of delirium focus on prevention and treatment with nonpharmacological or medication interventions, with the preponderance of evidence favoring multi-component nonpharmacological approaches to prevention as the most effective. Though use of antipsychotic medication in delirium is common, existing evidence does not support routine use, showing no clear benefit in clinically significant outcome measures and with evidence of harm in some studies. We therefore suggest that antipsychotics be used to treat agitation, psychosis, and distress associated with delirium at the lowest effective doses and shortest possible duration and not be considered a treatment of delirium itself. Future studies may clarify the use of other agents, such as melatonin and melatonin receptor agonists, alpha-2 receptor agonists, and anti-epileptics.

Cardiovascular autonomic dysfunction in "Long COVID": pathophysiology, heart rate variability, and inflammatory markers

Long COVID is characterized by persistent signs and symptoms that continue or develop for more than 4 weeks after acute COVID-19 infection. Patients with Long COVID experience a cardiovascular autonomic imbalance known as dysautonomia. However, the underlying autonomic pathophysiological mechanisms behind this remain unclear. Current hypotheses include neurotropism, cytokine storms, and inflammatory persistence. Certain immunological factors indicate autoimmune dysfunction, which can be used to identify patients at a higher risk of Long COVID. Heart rate variability can indicate autonomic imbalances in individuals suffering from Long COVID, and measurement is a non-invasive and low-cost method for assessing cardiovascular autonomic modulation. Additionally, biochemical inflammatory markers are used for diagnosing and monitoring Long COVID. These inflammatory markers can be used to improve the understanding of the mechanisms driving the inflammatory response and its effects on the sympathetic and parasympathetic pathways of the autonomic nervous system. Autonomic imbalances in patients with Long COVID may result in lower heart rate variability, impaired vagal activity, and substantial sympathovagal imbalance. New research on this subject must be encouraged to enhance the understanding of the long-term risks that cardiovascular autonomic imbalances can cause in individuals with Long COVID.

Microstructural alterations in hypoxia-related BRAIN centers after COVID-19 by using DTI: A preliminary study

PURPOSE

To investigate whether the diffusion tensor imaging (DTI) parameters alterations in the in hypoxia-related neuroanatomical localizations in patients after COVID-19. Additionally, the relationship between DTI findings and the clinical severity of the disease is evaluated.

METHODS

The patients with COVID-19 were classified into group 1 (total patients, n = 74), group 2 (outpatient, n = 46), and group 3 (inpatient, n = 28) and control (n = 52). Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were calculated from the bulbus, pons, thalamus, caudate nucleus, globus pallidum, putamen, and hippocampus. DTI parameters were compared between groups. Oxygen saturation, D dimer and lactate dehydrogenase (LDH) values associated with hypoxia were analyzed in inpatient group. Laboratory findings were correlated with ADC and FA values.

RESULTS

Increased ADC values in the thalamus, bulbus and pons were found in group 1 compared to control. Increased FA values in the thalamus, bulbus, globus pallidum and putamen were detected in group 1 compared to control. The FA and ADC values obtained from putamen were higher in group 3 compared to group 2. There was a negative correlation between basal ganglia and hippocampus FA values and plasma LDH values. The ADC values obtained from caudate nucleus were positively correlated with plasma D Dimer values.

CONCLUSION

ADC and FA changes may reveal hypoxia-related microstructural damage after COVID-19 infection. We speculated that the brainstem and basal ganglia can affected during the subacute period.

Neurological manifestations of SARS-CoV-2: complexity, mechanism and associated disorders

BACKGROUND

Coronaviruses such as Severe Acute Respiratory Syndrome coronavirus (SARS), Middle Eastern Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are associated with critical illnesses, including severe respiratory disorders. SARS-CoV-2 is the causative agent of the deadly COVID-19 illness, which has spread globally as a pandemic. SARS-CoV-2 may enter the human body through olfactory lobes and interact with the angiotensin-converting enzyme2 (ACE2) receptor, further facilitating cell binding and entry into the cells. Reports have shown that the virus can pass through the blood-brain barrier (BBB) and enter the central nervous system (CNS), resulting in various disorders. Cell entry by SARS-CoV-2 largely relies on TMPRSS2 and cathepsin L, which activate S protein. TMPRSS2 is found on the cell surface of respiratory, gastrointestinal and urogenital epithelium, while cathepsin-L is a part of endosomes.

AIM

The current review aims to provide information on how SARS-CoV-2 infection affects brain function.. Furthermore, CNS disorders associated with SARS-CoV-2 infection, including ischemic stroke, cerebral venous thrombosis, Guillain-Barré syndrome, multiple sclerosis, meningitis, and encephalitis, are discussed. The many probable mechanisms and paths involved in developing cerebrovascular problems in COVID patients are thoroughly detailed.

MAIN BODY

There have been reports that the SARS-CoV-2 virus can cross the blood-brain barrier (BBB) and enter the central nervous system (CNS), where it could cause a various illnesses. Patients suffering from COVID-19 experience a range of neurological complications, including sleep disorders, viral encephalitis, headaches, dysgeusia, and cognitive impairment. The presence of SARS-CoV-2 in the cerebrospinal fluid (CSF) of COVID-19 patients has been reported. Health experts also reported its presence in cortical neurons and human brain organoids. The possible mechanism of virus infiltration into the brain can be neurotropic, direct infiltration and cytokine storm-based pathways. The olfactory lobes could also be the primary pathway for the entrance of SARS-CoV-2 into the brain.

CONCLUSIONS

SARS-CoV-2 can lead to neurological complications, such as cerebrovascular manifestations, motor movement complications, and cognitive decline. COVID-19 infection can result in cerebrovascular symptoms and diseases, such as strokes and thrombosis. The virus can affect the neural system, disrupt cognitive function and cause neurological disorders. To combat the epidemic, it is crucial to repurpose drugs currently in use quickly and develop novel therapeutics.

Assessing the risk and costs of COVID-19 in immunocompromised populations in a large United States commercial insurance health plan: the EPOCH-US Study

OBJECTIVE

To estimate the prevalence of patients with an immunocompromising condition at risk for COVID-19, estimate COVID-19 prevalence rate (PR) and incidence rate (IR) by immunocompromising condition, and describe COVID-19-related healthcare resource utilization (HCRU) and costs.

METHODS

Using the Healthcare Integrated Research Database (HIRD), patients with ≥1 claim for an immunocompromising condition of interest or ≥2 claims for an immunosuppressive (IS) treatment and COVID-19 diagnosis during the infection period (1 April 2020-31 March 2022) and had ≥12 months baseline data were included. Cohorts (other than the composite cohort) were not mutually exclusive and were defined by each immunocompromising condition. Analyses were descriptive in nature.

RESULTS

Of the 16,873,161 patients in the source population, 2.7% (n = 458,049) were immunocompromised (IC). The COVID-19 IR for the composite IC cohort during the study period was 101.3 per 1000 person-years and the PR was 13.5%. The highest IR (195.0 per 1000 person-years) and PR (20.1%) were seen in the end-stage renal disease (ESRD) cohort; the lowest IR (68.3 per 1000 person-years) and PR (9.4%) were seen in the hematologic or solid tumor malignancy cohort. Mean costs for hospitalizations associated with the first COVID-19 diagnosis were estimated at nearly $1 billion (2021 United States dollars [USD]) for 14,516 IC patients, with a mean cost of $64,029 per patient.

CONCLUSIONS

Immunocompromised populations appear to be at substantial risk of severe COVID-19 outcomes, leading to increased costs and HCRU. Effective prophylactic options are still needed for these high-risk populations as the COVID-19 landscape evolves.

COVID-19 and the risk of neuromyelitis optica spectrum disorder: a Mendelian randomization study

Background

An increasing number of studies have elucidated a close nexus between COVID-19 phenotypes and neuromyelitis optica spectrum disorder (NMOSD), yet the causality between them remains enigmatic.

Methods

In this study, we conducted a Mendelian randomization (MR) analysis employing summary data sourced from genome-wide association studies (GWAS) pertaining to COVID-19 susceptibility, hospitalization, severity, and NMOSD. The primary MR analysis employed the Inverse variance weighted (IVW) approach, which was supplemented by MR-Egger, weighted median, simple mode, and weighted mode methods. We implemented various sensitivity analyses including Cochran's Q test, MR-PRESSO method, MR-Egger intercept, leave-one-out analysis, and funnel plot.

Results

The MR results demonstrated a nominal association between COVID-19 susceptibility and the risk of AQP4+ NMOSD, as evidenced by the IVW method (OR = 4.958; 95% CI: 1.322-18.585; P = 0.018). Conversely, no causal association was observed between COVID-19 susceptibility, hospitalization, or severity and the increased risk of NMOSD, AQP4-NMOSD, or AQP4+ NMOSD. The comprehensive sensitivity analyses further bolstered the robustness and consistency of the MR estimates.

Conclusion

Our findings provide compelling evidence for a causal effect of COVID-19 phenotype on AQP4+ NMOSD, shedding new light on the understanding of the comorbidity between COVID-19 and NMOSD.

Effect of Disease-Modifying Therapies on COVID-19 Vaccination Efficacy in Multiple Sclerosis Patients: A Comprehensive Review

According to current knowledge, the etiopathogenesis of multiple sclerosis (MS) is complex, involving genetic background as well as several environmental factors that result in dysimmunity in the central nervous system (CNS). MS is an immune-mediated, inflammatory neurological disease affecting the CNS. As part of its attack on the axons of the CNS, MS witnesses varying degrees of myelin and axonal loss. A total of about 20 disease-modifying therapies (DMTs) are available today that, both in clinical trials and in real-world studies, reduce disease activity, such as relapses, magnetic resonance imaging lesions, and disability accumulation. Currently, the world is facing an outbreak of the new coronavirus disease 2019 (COVID-19), which originated in Wuhan, Hubei Province, China, in December 2019 and spread rapidly around the globe. Viral infections play an important role in triggering and maintaining neuroinflammation through direct and indirect mechanisms. There is an old association between MS and viral infections. In the context of MS-related chronic inflammatory damage within the CNS, there has been concern regarding COVID-19 worsening neurological damage. A high rate of disability and increased susceptibility to infection have made MS patients particularly vulnerable. In addition, DMTs have been a concern during the pandemic since many DMTs have immunosuppressive properties. In this article, we discuss the impact of DMTs on COVID-19 risks and the effect of DMTs on COVID-19 vaccination efficacy and outcome in MS patients.

The landscape of abnormal pathway activation confers COVID-19 patients' molecular sequelae earlier than clinical phenotype

Rationale: The 2019 coronavirus disease (COVID-19) pandemic poses a significant threat to human health. After SARS-CoV-2 infection, major clinical concerns are organ damage and possible sequelae. Methods: In this study, we analyzed serum multi-omics data based on population-level, including healthy cohort, non-COVID-19 and COVID-19 covered different severity cohorts. We applied the pseudo-SpatioTemporal Consistency Alignment (pST-CA) strategy to correct for individualized disease course differences, and developed pseudo-deterioration timeline model and pseudo-recovery timeline model based on the "severe index" and "course index". Further, we comprehensively analyzed and discussed the dynamic damage signaling in COVID-19 deterioration and/or recovery, as well as the potential risk of sequelae. Results: The deterioration and course models based on the pST-CA strategy can effectively map the activation of blood molecular signals on cellular, pathway, functional and disease phenotypes in COVID-19 deterioration and throughout the disease course. The models revealed the neurological, cardiovascular, and hepatic toxicity present in SARS-CoV-2. The abundance of differentially expressed proteins and the activity of upstream regulators were comprehensively analyzed and evaluated to predict possible target drugs for SARS-CoV-2. On molecular docking simulation analysis, it was further demonstrated that blocking CEACAM1 is a potential therapeutic target for SARS-CoV-2. Conclusions: Clinically, the risk of organ failure and death in COVID-19 patients rises with increasing number of infections. Individualized sequelae prediction for patients and assessment of individualized intervenable targets and available drugs in combination with the upstream regulator analysis results are of great clinical value.

The Impact of COVID-19 on People Living with HIV-1 and HIV-1-Associated Neurological Complications

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the causative pathogen of the coronavirus disease 2019 (COVID-19) pandemic, a fatal respiratory illness. The associated risk factors for COVID-19 are old age and medical comorbidities. In the current combined antiretroviral therapy (cART) era, a significant portion of people living with HIV-1 (PLWH) with controlled viremia is older and with comorbidities, making these people vulnerable to SARS-CoV-2 infection and COVID-19-associated severe outcomes. Additionally, SARS-CoV-2 is neurotropic and causes neurological complications, resulting in a health burden and an adverse impact on PLWH and exacerbating HIV-1-associated neurocognitive disorder (HAND). The impact of SARS-CoV-2 infection and COVID-19 severity on neuroinflammation, the development of HAND and preexisting HAND is poorly explored. In the present review, we compiled the current knowledge of differences and similarities between SARS-CoV-2 and HIV-1, the conditions of the SARS-CoV-2/COVID-19 and HIV-1/AIDS syndemic and their impact on the central nervous system (CNS). Risk factors of COVID-19 on PLWH and neurological manifestations, inflammatory mechanisms leading to the neurological syndrome, the development of HAND, and its influence on preexisting HAND are also discussed. Finally, we have reviewed the challenges of the present syndemic on the world population, with a particular emphasis on PLWH.

Neurological damages in COVID-19 patients: Mechanisms and preventive interventions

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus, causes coronavirus disease 2019 (COVID-19) which led to neurological damage and increased mortality worldwide in its second and third waves. It is associated with systemic inflammation, myocardial infarction, neurological illness including ischemic strokes (e.g., cardiac and cerebral ischemia), and even death through multi-organ failure. At the early stage, the virus infects the lung epithelial cells and is slowly transmitted to the other organs including the gastrointestinal tract, blood vessels, kidneys, heart, and brain. The neurological effect of the virus is mainly due to hypoxia-driven reactive oxygen species (ROS) and generated cytokine storm. Internalization of SARS-CoV-2 triggers ROS production and modulation of the immunological cascade which ultimately initiates the hypercoagulable state and vascular thrombosis. Suppression of immunological machinery and inhibition of ROS play an important role in neurological disturbances. So, COVID-19 associated damage to the central nervous system, patients need special care to prevent multi-organ failure at later stages of disease progression. Here in this review, we are selectively discussing these issues and possible antioxidant-based prevention therapies for COVID-19-associated neurological damage that leads to multi-organ failure.

Mouse Adapted SARS-CoV-2 Model Induces "Long-COVID" Neuropathology in BALB/c Mice

The novel coronavirus SARS-CoV-2 has caused significant global morbidity and mortality and continues to burden patients with persisting neurological dysfunction. COVID-19 survivors develop debilitating symptoms to include neuro-psychological dysfunction, termed "Long COVID", which can cause significant reduction of quality of life. Despite vigorous model development, the possible cause of these symptoms and the underlying pathophysiology of this devastating disease remains elusive. Mouse adapted (MA10) SARS-CoV-2 is a novel mouse-based model of COVID-19 which simulates the clinical symptoms of respiratory distress associated with SARS-CoV-2 infection in mice. In this study, we evaluated the long-term effects of MA10 infection on brain pathology and neuroinflammation. 10-week and 1-year old female BALB/cAnNHsd mice were infected intranasally with 10 ⁴ plaque-forming units (PFU) and 10 ³ PFU of SARS-CoV-2 MA10, respectively, and the brain was examined 60 days post-infection (dpi). Immunohistochemical analysis showed a decrease in the neuronal nuclear protein NeuN and an increase in Iba-1 positive amoeboid microglia in the hippocampus after MA10 infection, indicating long-term neurological changes in a brain area which is critical for long-term memory consolidation and processing. Importantly, these changes were seen in 40-50% of infected mice, which correlates to prevalence of LC seen clinically. Our data shows for the first time that MA10 infection induces neuropathological outcomes several weeks after infection at similar rates of observed clinical prevalence of "Long COVID". These observations strengthen the MA10 model as a viable model for study of the long-term effects of SARS-CoV-2 in humans. Establishing the viability of this model is a key step towards the rapid development of novel therapeutic strategies to ameliorate neuroinflammation and restore brain function in those suffering from the persistent cognitive dysfunction of "Long-COVID".

Pathophysiology of SARS-CoV2 Mediated Depression, Therapeutics, and Consequences: A Comprehensive Narrative

The Coronavirus Disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV-2), belongs to emerging and reemerging diseases, which was first identified and reported in Wuhan, China, in December 2019. The genetic sequence of SARS-CoV-2 was similar to the SARS virus, a β-coronavirus. The epidemiological studies suggest that the transmission of SARS-CoV-2 mainly occurs from an infected person to others through close contact with the respiratory droplets or by having contact with SARS-CoV-2 adhering to objects and surfaces. The incubation period ranges from 5 to14 days. The symptoms include fever, dry cough, tiredness, aches, chest pain, conjunctivitis, diarrhea, headache, difficulty in breathing or short breath, loss of taste, smell, rashes on the skin, and sore throat. Some reports indicated that males exhibited lower scores than females, the younger populations displayed increased symptoms, Chinese/Taiwanese people registered only scarce symptoms, and Canadians experienced more symptoms. The results of several studies suggested that while COVID-19 had a significant effect on depression, job instability affected anxiety and depression. The diagnostics to detect the presence of coronavirus involve ELISA and RT-PCR. There is no specific treatment available to eradicate COVID-19. The therapeutics used to treat COVID 19 exhibited severe side effects. Recently, some Indian traditional medicinal plants have shown promise in reducing the risk of viral infection and also boosting the immunity of an individual. This paper presents an overview of the current status of depression in the SARS CoV2 infected people and the measures required to overcome COVID-19 induced depression in patients even after recovery.

Targeting of neuroinflammation by glibenclamide in Covid-19: old weapon from arsenal

In coronavirus disease 2019 (Covid-19) era, neuroinflammation may develop due to neuronal tropism of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and/or associated immune activation, cytokine storm, and psychological stress. SARS-CoV-2 infection and linked cytokine storm may cause blood-brain barrier (BBB) injury through which activated immune cells and SARS-CoV-2 can pass into the brain causing activation of glial cells with subsequent neuroinflammation. Different therapeutic regimens were suggested to alleviate Covid-19-induced neuroinflammation. Since glibenclamide has anti-inflammatory and neuroprotective effects, it could be effective in mitigation of SARS-CoV-2 infection-induced neuroinflammation. Glibenclamide is a second-generation drug from the sulfonylurea family, which acts by inhibiting the adenosine triphosphate (ATP)-sensitive K channel in the regulatory subunit of type 1 sulfonylurea receptor (SUR-1) in pancreatic β cells. Glibenclamide reduces neuroinflammation and associated BBB injury by inhibiting the nod-like receptor pyrin 3 (NLRP3) inflammasome, oxidative stress, and microglial activation. Therefore, glibenclamide through inhibition of NLRP3 inflammasome, microglial activation, and oxidative stress may attenuate SARS-CoV-2-mediated neuroinflammation.

COVID-19-Induced Stroke and the Potential of Using Mesenchymal Stem Cells-Derived Extracellular Vesicles in the Regulation of Neuroinflammation

Ischemic stroke (IS) is a known neurological complication of COVID-19 infection, which is associated with high mortality and disability. Following IS, secondary neuroinflammation that occurs can play both harmful and beneficial roles and lead to further injury or repair of damaged neuronal tissue, respectively. Since inflammation plays a pivotal role in the pathogenesis of COVID-19-induced stroke, targeting neuroinflammation could be an effective strategy for modulating the immune responses following ischemic events. Numerous investigations have indicated that the application of mesenchymal stem cells-derived extracellular vesicles (MSC-EVs) improves functional recovery following stroke, mainly through reducing neuroinflammation as well as promoting neurogenesis and angiogenesis. Therefore, MSC-EVs can be applied for the regulation of SARS-CoV-2-mediated inflammation and the management of COVID-19- related ischemic events. In this study, we have first described the advantages and disadvantages of neuroinflammation in the pathological evolution after IS and summarized the characteristics of neuroinflammation in COVID-19-related stroke. Then, we have discussed the potential benefit of MSC-EVs in the regulation of inflammatory responses after COVID-19-induced ischemic events.

Mouse Adapted SARS-CoV-2 (MA10) Viral Infection Induces Neuroinflammation in Standard Laboratory Mice

Increasing evidence suggests that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection impacts neurological function both acutely and chronically, even in the absence of pronounced respiratory distress. Developing clinically relevant laboratory mouse models of the neuropathogenesis of SARS-CoV-2 infection is an important step toward elucidating the underlying mechanisms of SARS-CoV-2-induced neurological dysfunction. Although various transgenic models and viral delivery methods have been used to study the infection potential of SARS-CoV-2 in mice, the use of commonly available laboratory mice would facilitate the study of SARS-CoV-2 neuropathology. Herein we show neuroinflammatory profiles of immunologically intact mice, C57BL/6J and BALB/c, as well as immunodeficient (Rag2-/-) mice, to a mouse-adapted strain of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2 (MA10)). Our findings indicate that brain IL-6 levels are significantly higher in BALB/c male mice infected with SARS-CoV-2 MA10. Additionally, blood-brain barrier integrity, as measured by the vascular tight junction protein claudin-5, was reduced by SARS-CoV-2 MA10 infection in all three strains. Brain glial fibrillary acidic protein (GFAP) mRNA was also elevated in male C57BL/6J infected mice compared with the mock group. Lastly, immune-vascular effects of SARS-CoV-2 (MA10), as measured by H&E scores, demonstrate an increase in perivascular lymphocyte cuffing (PLC) at 30 days post-infection among infected female BALB/c mice with a significant increase in PLC over time only in SARS-CoV-2 MA10) infected mice. Our study is the first to demonstrate that SARS-CoV-2 (MA10) infection induces neuroinflammation in laboratory mice and could be used as a novel model to study SARS-CoV-2-mediated cerebrovascular pathology.

Cognitive and emotional impairments associated with COVID-19 (literature review)

Background. Currently, there are two main areas of study of the impact of a new coronavirus infection on mental processes: the first is in connection with the regime of self-isolation and restrictions in a pandemic; the second – with the impact of the pathological process itself and the post-covid syndrome on the central nervous system. The results of the studies indicate the relationship of this infection with local lesions of the brain and the corresponding disturbances in the functioning of mental processes.The aim of the research. To systematize and analyze the results of studies on the main routes of penetration of the SARS-CoV-2 virus into the central nervous system, cognitive and emotional disorders in people who have recovered from COVID-19, and to discuss the areas of psychological rehabilitation for this group of patients.Materials and methods. Information search was carried out using Internet resources (PubMed, Web of Science, Scopus, bmj.com, eLibrary.ru, frontiersin.org, sciencedirect. com, ncbi.nlm.nih.gov), literature sources were analyzed for the period from May of 2020 to November of 2021 for the following keywords: COVID-19, SARS-CoV-2, cognitive functions, cognitions, cognitive impairments, emotional dysfunction, affective dysfunction.Results. According to the analysis of the literature, most researchers identify the neurogenic pathway of SARS-CoV-2 penetration into the CNS, as well as penetration through the bloodstream or through cerebral lymphatic drainage, which are a possible cause of mental disorders of a neurological nature. Correction of these violations involves the creation of a comprehensive system of rehabilitation with the inclusion of psychotherapeutic methods.Conclusions. Despite the lack of a single picture describing the specifics of cognitive and affective symptoms in COVID-19, in the most general terms, there is a certain consensus. So, quite often, post-COVID cognitive symptoms are characterized by impaired memory and attention, and post-COVID affective symptoms are characterized by increased levels of anxiety, depression, and fatigue. The issues of diagnosis and correction of disorders in post-COVID syndrome and the admissibility of the existence of this diagnosis are still relevant.

Tinnitus and biopsychosocial ramifications of COVID-19 associated with severe suicide attempt-a case report

The COVID-19 disease has been linked to multiple physical and mental health consequences which may be partially attributed to multi-system modulation by inflammatory cytokines. Post-acute sequelae (PASC) of SARS-CoV-2 infection, colloquially known as "Long Covid", has become an established entity. However, screening guidelines and interventions for COVID-19 survivors remain elusive. The neuropsychiatric sequelae of COVID-19 seem to originate from a cumulation of biopsychosocial factors which may predispose individuals to acute psychiatric decompensation irrespective of a previously diagnosed mental illness. We present a case report which illustrates how cognitive issues and medical complaints may negatively interact resulting in significant depression and a severe suicide attempt.

Neurological Complications Associated With SARS-CoV-2 Infection: A Single-Centre Experience

BACKGROUND

The clinical presentation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can range from mild or moderate disease (80% of the cases) to severe disease (15%) requiring oxygen support, and critical disease (5%), associated with acute respiratory distress syndrome and admission to the intensive care unit (ICU). In critically ill patients, prone positioning can be used to optimize oxygenation. Although there is a favourable response to this strategy, being a life-saving measure, additional associated complications may appear, including compressive neuropathies. Despite respiratory affection being more common, SARS-CoV-2 infection can also attack other systems and can, under certain conditions, affect the central or peripheral nervous system. It has been described that neurological manifestations can result from the neuroinvasive properties of the SARS-CoV-2 or as an indirect consequence of multiorgan dysfunction.

AIMS

We intend to report the patients who presented with neurological complications associated with coronavirus disease 2019 (COVID-19) and/or complications of its treatment, followed in our physical and rehabilitation medicine (PRM) service.

MATERIALS AND METHODS

A retrospective analysis of patients admitted to the PRM ward with outpatient consultation in the context of post-COVID-19 status between April 2020 and November 2021 (the period of the highest prevalence of infection) was carried out. Patients with neurological complications after SARS-CoV-2 infection and consequently a decline in previous functionality were identified.

RESULTS

Thirteen patients (23.6%) admitted to the PRM ward had peripheral neurological complications, documented by electroneuromyography, including Guillain-Barré syndrome, sensory-motor polyneuropathy, peroneal nerve injury, femoral nerve injury, and lumbar plexus injury. The neurological complications of the patients followed in a post-COVID-19 consultation were also evaluated. Eight patients (20%) reported neurological sequelae. Five patients presented peripheral nerve damage (peroneal, accessory, ulnar, and recurrent laryngeal) of undefined aetiology, diagnosed after the acute phase of hospitalization. Two patients had COVID-19 infection followed by ischemic stroke (vertebrobasilar and middle cerebral artery), requiring hospitalization in the acute phase. One patient had COVID-19 infection followed by longitudinal myelitis, with positive anti-myelin oligodendrocyte glycoprotein (MOG). All patients required follow-up by the rehabilitation team with partial recovery of deficits.

CONCLUSIONS

 All patients admitted to the PRM ward with neurological manifestations had critical disease and symptoms compatible with peripheral nervous system involvement. Patients admitted to the PRM consultation had different levels of viral disease severity and had sequelae related to peripheral and central nervous system disorders. Identifying the aetiology of these injuries is essential for us to act on their prevention, particularly with regard to indirect complications, such as compressive neuropathies. It will be necessary to maintain the follow-up of these patients to understand the evolution of the neurological consequences associated with COVID-19.

Delivery of Theranostic Nanoparticles to Various Cancers by Means of Integrin-Binding Peptides

Active targeting of tumors is believed to be the key to efficient cancer therapy and accurate, early-stage diagnostics. Active targeting implies minimized off-targeting and associated cytotoxicity towards healthy tissue. One way to acquire active targeting is to employ conjugates of therapeutic agents with ligands known to bind receptors overexpressed onto cancer cells. The integrin receptor family has been studied as a target for cancer treatment for almost fifty years. However, systematic knowledge on their effects on cancer cells, is yet lacking, especially when utilized as an active targeting ligand for particulate formulations. Decoration with various integrin-targeting peptides has been reported to increase nanoparticle accumulation in tumors ≥ 3-fold when compared to passively targeted delivery. In recent years, many newly discovered or rationally designed integrin-binding peptides with excellent specificity towards a single integrin receptor have emerged. Here, we show a comprehensive analysis of previously unreviewed integrin-binding peptides, provide diverse modification routes for nanoparticle conjugation, and showcase the most notable examples of their use for tumor and metastases visualization and eradication to date, as well as possibilities for combined cancer therapies for a synergetic effect. This review aims to highlight the latest advancements in integrin-binding peptide development and is directed to aid transition to the development of novel nanoparticle-based theranostic agents for cancer therapy.

Role of SARS-CoV-2-induced Cytokine Storm in Multi-Organ Failure: Molecular Pathways and Potential Therapeutic Options

Coronavirus disease 2019 (COVID-19) outbreak has become a global public health emergency and has led to devastating results. Mounting evidence proposes that the disease causes severe pulmonary involvement and influences different organs, leading to a critical situation named multi-organ failure. It is yet to be fully clarified how the disease becomes so deadly in some patients. However, it is proven that a condition called “cytokine storm” is involved in the deterioration of COVID-19. Although beneficial, sustained production of cytokines and overabundance of inflammatory mediators causing cytokine storm can lead to collateral vital organ damages. Furthermore, cytokine storm can cause post-COVID-19 syndrome (PCS), an important cause of morbidity after the acute phase of COVID-19. Herein, we aim to explain the possible pathophysiology mechanisms involved in COVID-19-related cytokine storm and its association with multi-organ failure and PCS. We also discuss the latest advances in finding the potential therapeutic targets to control cytokine storm wishing to answer unmet clinical demands for treatment of COVID-19.

The Adverse Outcome Pathway Framework Applied to Neurological Symptoms of COVID-19

Several reports have shown that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has the potential to also be neurotropic. However, the mechanisms by which SARS-CoV-2 induces neurologic injury, including neurological and/or psychological symptoms, remain unclear. In this review, the available knowledge on the neurobiological mechanisms underlying COVID-19 was organized using the AOP framework. Four AOPs leading to neurological adverse outcomes (AO), anosmia, encephalitis, stroke, and seizure, were developed. Biological key events (KEs) identified to induce these AOs included binding to ACE2, blood–brain barrier (BBB) disruption, hypoxia, neuroinflammation, and oxidative stress. The modularity of AOPs allows the construction of AOP networks to visualize core pathways and recognize neuroinflammation and BBB disruption as shared mechanisms. Furthermore, the impact on the neurological AOPs of COVID-19 by modulating and multiscale factors such as age, psychological stress, nutrition, poverty, and food insecurity was discussed. Organizing the existing knowledge along an AOP framework can represent a valuable tool to understand disease mechanisms and identify data gaps and potentially contribute to treatment, and prevention. This AOP-aligned approach also facilitates synergy between experts from different backgrounds, while the fast-evolving and disruptive nature of COVID-19 emphasizes the need for interdisciplinarity and cross-community research.

Systems Bioinformatics Reveals Possible Relationship between COVID-19 and the Development of Neurological Diseases and Neuropsychiatric Disorders

Coronavirus Disease 2019 (COVID-19) is associated with increased incidence of neurological diseases and neuropsychiatric disorders after infection, but how it contributes to their development remains under investigation. Here, we investigate the possible relationship between COVID-19 and the development of ten neurological disorders and three neuropsychiatric disorders by exploring two pathological mechanisms: (i) dysregulation of host biological processes via virus-host protein-protein interactions (PPIs), and (ii) autoreactivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epitopes with host "self" proteins via molecular mimicry. We also identify potential genetic risk factors which in combination with SARS-CoV-2 infection might lead to disease development. Our analysis indicated that neurodegenerative diseases (NDs) have a higher number of disease-associated biological processes that can be modulated by SARS-CoV-2 via virus-host PPIs than neuropsychiatric disorders. The sequence similarity analysis indicated the presence of several matching 5-mer and/or 6-mer linear motifs between SARS-CoV-2 epitopes with autoreactive epitopes found in Alzheimer's Disease (AD), Parkinson's Disease (PD), Myasthenia Gravis (MG) and Multiple Sclerosis (MS). The results include autoreactive epitopes that recognize amyloid-beta precursor protein (APP), microtubule-associated protein tau (MAPT), acetylcholine receptors, glial fibrillary acidic protein (GFAP), neurofilament light polypeptide (NfL) and major myelin proteins. Altogether, our results suggest that there might be an increased risk for the development of NDs after COVID-19 both via autoreactivity and virus-host PPIs.

Headaches and Dizziness as Disabling, Persistent Symptoms in Patients with Long COVID-A National Multicentre Study

Background: Currently, about 15% of coronavirus disease-19 (COVID-19) patients are affected by Long COVID worldwide; however, this condition has not yet been sufficiently studied. The aim of this study was to identify the impact of symptom persistence as well as clinical and socio-demographic variables in a cohort of people with Long COVID. Methods: We conducted a descriptive cross-sectional study of a sample of adult patients from different Spanish regions presenting with Long COVID. Data collection was conducted between April and July 2021. Functional status and dependency were assessed. Results: A multivariate linear regression was performed, and the model was statistically significant (F (7; 114) = 8.79; p < 0.001), according to the overall ALDQ score. The variables with a statistically significant effect on the degree of dependence were age (p = 0.014), time since diagnosis (p = 0.02), headaches (p = 0.031), and dizziness (p = 0.039). Functional status post-COVID showed a positive and significant relationship with the percentage of dependence (p < 0.001). Conclusions: People affected by Long COVID showed moderate dependency status and limitations in functionality. Those with neurological symptoms, such as dizziness and headaches, as well as older age, showed a higher degree of dependency. Improvements in dependency status occurred with increasing time since diagnosis.

Cognitive dysfunction associated with COVID-19: Prognostic role of circulating biomarkers and microRNAs

COVID-19 is renowned as a multi-organ disease having subacute and long-term effects with a broad spectrum of clinical manifestations. The evolving scientific and clinical evidence demonstrates that the frequency of cognitive impairment after COVID-19 is high and it is crucial to explore more clinical research and implement proper diagnostic and treatment strategies. Several central nervous system complications have been reported as comorbidities of COVID-19. The changes in cognitive function associated with neurodegenerative diseases develop slowly over time and are only diagnosed at an already advanced stage of molecular pathology. Hence, understanding the common links between COVID-19 and neurodegenerative diseases will broaden our knowledge and help in strategizing prognostic and therapeutic approaches. The present review focuses on the diverse neurodegenerative changes associated with COVID-19 and will highlight the importance of major circulating biomarkers and microRNAs (miRNAs) associated with the disease progression and severity. The literature analysis showed that major proteins associated with central nervous system function, such as Glial fibrillary acidic protein, neurofilament light chain, p-tau 181, Ubiquitin C-terminal hydrolase L1, S100 calcium-binding protein B, Neuron-specific enolase and various inflammatory cytokines, were significantly altered in COVID-19 patients. Furthermore, among various miRNAs that are having pivotal roles in various neurodegenerative diseases, miR-146a, miR-155, Let-7b, miR-31, miR-16 and miR-21 have shown significant dysregulation in COVID-19 patients. Thus the review consolidates the important findings from the numerous studies to unravel the underlying mechanism of neurological sequelae in COVID-19 and the possible association of circulatory biomarkers, which may serve as prognostic predictors and therapeutic targets in future research.

Whole-transcriptome sequencing data reveals a disparate cognitive and immune signature in COVID-19 patients with and without dementia

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused more than 6.3 million deaths worldwide. Recent evidence has indicated that elderly people with dementia are particularly vulnerable to COVID-19 and severe disease outcomes. However, its molecular mechanism remains largely unknown. Here, we retrieved frontal cortex samples of COVID-19 patients from the Gene Expression Omnibus database and performed a systematic transcriptomic analysis to compare COVID-19 patients and controls with or without dementia. In nondemented patients, SARS-CoV-2 infection obviously activated T helper type 2 (Th2) cell-mediated humoral immunity and reduced the pathogenesis of dementia-related Alzheimer's disease and Parkinson's disease. In demented patients, conversely, SARS-CoV-2 infection significantly increased T helper type 1 (Th1) cell-mediated cellular immunity and exacerbated the progression of dementia-related diseases. We further analyzed the molecular characteristics of COVID-19 patients with and without dementia. Compared with nondemented COVID-19 patients, demented COVID-19 patients showed decreased enrichment scores of Calcium signaling pathway, Neuroactive ligand-receptor interaction, ABC transporters, and Peroxisome, and increased enrichment scores of Olfactory transduction and Regulation of autophagy. The ratio of Th1/Th2 cells was significantly increased from 1.17 in nondemented COVID-19 patients to 33.32 in demented COVID-19 patients. Taken together, our findings provide transcriptomic evidence that COVID-19 has distinct influences on cognitive function and immune response in patients with and without dementia.

Exacerbation of Pre-existing Neurological Symptoms With COVID-19 in Patients With Chronic Neurological Diseases: An Updated Systematic Review

The neurotropism of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can potentially explain the worsening of symptoms in patients with a history of neurological conditions such as stroke, Parkinson's disease, Alzheimer's, and epilepsy. Several studies have reported that these pre-existing conditions may worsen with a higher frequency of flare-ups, thus resulting in a more significant risk of patient mortality. In this review, we sought to provide an overview of the relationship between pre-existing neurological disorders and COVID-19, focusing on whether the initial infection directly influenced the severity of symptoms. We systematically searched the electronic database PubMed (MEDLINE) and used specific keywords related to our aims from January 2020 to July 2022. All articles published on COVID-19 with keywords pertaining to pre-existing neurological diseases were retrieved and subsequently analyzed. After independent review, the data from 107 articles were selected and evaluated. After analyzing the data from selected articles reviewing the effect of COVID-19 on neurological conditions, we have documented the relationship between said pre-existing neurological diseases, showing an increased risk of hospitalization, admission length, worsening of symptoms, and even mortality in COVID-19 patients.

The gut-brain axis and sodium appetite: Can inflammation-related signaling influence the control of sodium intake?

Sodium is the main cation present in the extracellular fluid. Sodium and water content in the body are responsible for volume and osmotic homeostasis through mechanisms involving sodium and water excretion and intake. When body sodium content decreases below the homeostatic threshold, a condition termed sodium deficiency, highly motivated sodium seeking, and intake occurs. This is termed sodium appetite. Classically, sodium and water intakes are controlled by a number of neuroendocrine mechanisms that include signaling molecules from the renin-angiotensin-aldosterone system acting in the central nervous system (CNS). However, recent findings have shown that sodium and water intakes can also be influenced by inflammatory agents and mediators acting in the CNS. For instance, central infusion of IL-1β or TNF-α can directly affect sodium and water consumption in animal models. Some dietary conditions, such as high salt intake, have been shown to change the intestinal microbiome composition, stimulating the immune branch of the gut-brain axis through the production of inflammatory cytokines, such as IL-17, which can stimulate the brain immune system. In this review, we address the latest findings supporting the hypothesis that immune signaling in the brain could produce a reduction in thirst and sodium appetite and, therefore, contribute to sodium intake control.

New Insights into the Molecular Interplay between Human Herpesviruses and Alzheimer’s Disease—A Narrative Review

Human herpesviruses (HHVs) have been implicated as possible risk factors in Alzheimer’s disease (AD) pathogenesis. Persistent lifelong HHVs infections may directly or indirectly contribute to the generation of AD hallmarks: amyloid beta (Aβ) plaques, neurofibrillary tangles composed of hyperphosphorylated tau proteins, and synaptic loss. The present review focuses on summarizing current knowledge on the molecular mechanistic links between HHVs and AD that include processes involved in Aβ accumulation, tau protein hyperphosphorylation, autophagy, oxidative stress, and neuroinflammation. A PubMed search was performed to collect all the available research data regarding the above mentioned mechanistic links between HHVs and AD pathology. The vast majority of research articles referred to the different pathways exploited by Herpes Simplex Virus 1 that could lead to AD pathology, while a few studies highlighted the emerging role of HHV 6, cytomegalovirus, and Epstein–Barr Virus. The elucidation of such potential links may guide the development of novel diagnostics and therapeutics to counter this devastating neurological disorder that until now remains incurable.

Neuroprotective Drug Discovery From Phytochemicals and Metabolites for CNS Viral Infection: A Systems Biology Approach With Clinical and Imaging Validation

Background

Recent studies have reported that pulmo-neurotropic viruses can cause systemic invasion leading to acute respiratory failure and neuroinfection. The tetracycline class of secondary metabolites of microorganisms is effective against several migrating neurotropic viral disorders, as Japanese-Encephalitis (JE), Severe-Acute-Respiratory-Syndrome Coronavirus-2 (SARS-COV2), Human-Immunodeficiency-Virus (HIV), and Simian-Immunodeficiency-Virus (SIV). Another microbial secondary metabolite, cephalosporin, can be used for anti-viral combination therapy. However, a substantial public health debacle is viral resistance to such antibiotics, and, thus, one needs to explore the antiviral efficiency of other secondary metabolites, as phytochemicals. Hence, here, we investigate phytochemicals like podophyllotoxin, chlorogenic acid, naringenin, and quercetin for therapeutic efficiency in neurotropic viral infections.

Methods

To investigate the possibility of the afferent neural pathway of migrating virus in man, MRI scanning was performed on human subjects, whereby the connections between cranial nerves and the brain-stem/limbic-region were assessed by fiber-tractography. Moreover, human clinical-trial assessment (n = 140, p = 0.028) was done for formulating a quantitative model of antiviral pharmacological intervention. Furthermore, docking studies were performed to identify the binding affinity of phytochemicals toward antiviral targets as (i) host receptor [Angiotensin-converting Enzyme-2], (ii) main protease of SARS-COV2 virus (iii) NS3-Helicase/Nucleoside triphosphatase of Japanese-encephalitis-virus, and the affinities were compared to standard tetracycline and cephalosporin antibiotics. Then, network pharmacology analysis was utilized to identify the possible mechanism of action of those phytochemicals.

Results

Human MRI-tractography analysis showed fiber connectivity, as: (a) Path-1: From the olfactory nerve to the limbic region (2) Path-2: From the peripheral glossopharyngeal nerve and vagus nerves to the midbrain-respiratory-center. Docking studies revealed comparable binding affinity of phytochemicals, tetracycline, and cephalosporin antibiotics toward both (a) virus receptors, (b) host cell receptors where virus-receptor binds. The phytochemicals effectively countered the cytokine storm-induced neuroinflammation, a critical pathogenic pathway. We also found that a systems-biology-based double-hit mathematical bi-exponential model accounts for patient survival-curve under antiviral treatment, thus furnishing a quantitative-clinical framework of secondary metabolite action on virus and host cells.

Conclusion

Due to the current viral resistance to antibiotics, we identified novel phytochemicals that can have clinical therapeutic application to neurotropic virus infection. Based on human MRI scanning and clinical-trial analysis, we demarcated the anatomical pathway and systems-biology-based quantitative formulation of the mechanism of antiviral action.

SARS-CoV-2 Brain Regional Detection, Histopathology, Gene Expression, and Immunomodulatory Changes in Decedents with COVID-19

Brains of 42 COVID-19 decedents and 107 non-COVID-19 controls were studied. RT-PCR screening of 16 regions from 20 COVID-19 autopsies found SARS-CoV-2 E gene viral sequences in 7 regions (2.5% of 320 samples), concentrated in 4/20 subjects (20%). Additional screening of olfactory bulb (OB), amygdala (AMY) and entorhinal area for E, N1, N2, RNA-dependent RNA polymerase, and S gene sequences detected one or more of these in OB in 8/21 subjects (38%). It is uncertain whether these RNA sequences represent viable virus. Significant histopathology was limited to 2/42 cases (4.8%), one with a large acute cerebral infarct and one with hemorrhagic encephalitis. Case-control RNAseq in OB and AMY found more than 5000 and 700 differentially expressed genes, respectively, unrelated to RT-PCR results; these involved immune response, neuronal constituents, and olfactory/taste receptor genes. Olfactory marker protein-1 reduction indicated COVID-19-related loss of OB olfactory mucosa afferents. Iba-1-immunoreactive microglia had reduced area fractions in cerebellar cortex and AMY, and cytokine arrays showed generalized downregulation in AMY and upregulation in blood serum in COVID-19 cases. Although OB is a major brain portal for SARS-CoV-2, COVID-19 brain changes are more likely due to blood-borne immune mediators and trans-synaptic gene expression changes arising from OB deafferentation.

Pathogenic Mechanism and Multi-omics Analysis of Oral Manifestations in COVID-19

Coronavirus disease 2019 (COVID-19) is a respiratory infectious disease that seriously threatens human life. The clinical manifestations of severe COVID-19 include acute respiratory distress syndrome and multiple organ failure. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of COVID-19, spreads through contaminated droplets. SARS-CoV-2 particles have been detected in the saliva of COVID-19 patients, implying that the virus can infect and damage the oral cavity. The oral manifestations of COVID-19 include xerostomia and gustatory dysfunction. Numerous studies showed that the four structural proteins of SARS-CoV-2 are its potential pathogenic factors, especially the S protein, which binds to human ACE2 receptors facilitating the entry of the virus into the host cells. Usually, upon entry into the host cell, a pathogen triggers the host’s immune response. However, a mount of multi-omics and immunological analyses revealed that COVID-19 is caused by immune dysregulation. A decrease in the number and phenotypes of immune cells, IFN-1 production and excessive release of certain cytokines have also been reported. In conclusion, this review summarizes the oral manifestations of COVID-19 and multi-omics analysis of SARS-CoV-2 infection.

Nervous system manifestations related to COVID-19 and their possible mechanisms

In December 2019, the novel coronavirus disease (COVID-19) due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection broke. With the gradual deepening understanding of SARS-CoV-2 and COVID-19, researchers and clinicians noticed that this disease is closely related to the nervous system and has complex effects on the central nervous system (CNS) and peripheral nervous system (PNS). In this review, we summarize the effects and mechanisms of SARS-CoV-2 on the nervous system, including the pathways of invasion, direct and indirect effects, and associated neuropsychiatric diseases, to deepen our knowledge and understanding of the relationship between COVID-19 and the nervous system.