The chronic neuropsychiatric sequelae of COVID-19: The need for a prospective study of viral impact on brain functioning

Adapting the UK Biobank Brain Imaging Protocol and Analysis Pipeline for the C-MORE Multi-Organ Study of COVID-19 Survivors

SARS-CoV-2 infection has been shown to damage multiple organs, including the brain. Multiorgan MRI can provide further insight on the repercussions of COVID-19 on organ health but requires a balance between richness and quality of data acquisition and total scan duration. We adapted the UK Biobank brain MRI protocol to produce high-quality images while being suitable as part of a post-COVID-19 multiorgan MRI exam. The analysis pipeline, also adapted from UK Biobank, includes new imaging-derived phenotypes (IDPs) designed to assess the possible effects of COVID-19. A first application of the protocol and pipeline was performed in 51 COVID-19 patients post-hospital discharge and 25 controls participating in the Oxford C-MORE study. The protocol acquires high resolution T1, T2-FLAIR, diffusion weighted images, susceptibility weighted images, and arterial spin labelling data in 17 min. The automated imaging pipeline derives 1,575 IDPs, assessing brain anatomy (including olfactory bulb volume and intensity) and tissue perfusion, hyperintensities, diffusivity, and susceptibility. In the C-MORE data, IDPs related to atrophy, small vessel disease and olfactory bulbs were consistent with clinical radiology reports. Our exploratory analysis tentatively revealed some group differences between recovered COVID-19 patients and controls, across severity groups, but not across anosmia groups. Follow-up imaging in the C-MORE study is currently ongoing, and this protocol is now being used in other large-scale studies. The protocol, pipeline code and data are openly available and will further contribute to the understanding of the medium to long-term effects of COVID-19.

ASNTR's Venture into a Hybrid Conference: Lessons Learned During the COVID-19 Pandemic

The 28th American Society for Neural Therapy and Repair (ASNTR) returned to the Sheraton Sand Key in Clearwater Beach, Florida after an 18 month hiatus. Like nearly all conferences during the pandemic, the ASNTR conference was held in person while offering a virtual option to the event. These formats are advantageous for those under travel restrictions or personal constraints, but they lack the spontaneity of in-person connections. Highlights from the meeting included the return of the Bernard Sanberg Memorial Award and the Roy Bakay Memorial lecture. The presidential lecture was given by Gabriel de Erausquin, who discussed the possibility of long-term CNS effects resulting from SARS-CoV2 infection. With both virtual and in-person events, including oral and poster presentations, the ASNTR managed to maintain the unique essence of this small important meeting.

Psychiatric sequelae in COVID-19 survivors: A narrative review

In December 2019, a novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was initially reported in Wuhan, China. Previous epidemics including SARS and middle east respiratory syndrome raises concern that COVID-19 infection may pose a significant threat to the mental health of affected individuals. Studies and reviews have shown the acute psychiatric manifestations in COVID-19 patients, although long term psychiatric sequelae are predicted, there are only few review studies about the long term psychiatry outcome in COVID-19 survivors. Clinically significant post-traumatic stress disorder, anxiety, and/or depression among COVID-19 survivors during 14-90 d were observed following the diagnosis. Risk of anxiety or depression were higher in patients with more severe illness at 6 mo follow-up, early convalescence, and at 1 mo follow-up. Diagnosis of COVID-19 Led to more first diagnoses and relapses of psychiatric illness during the first 14-90 d after COVID-19 diagnosis. The possible underlying mechanisms of psychiatric sequelae in COVID-19 infection are neurotropism, immune response to SARS-CoV-2, hypothalamo-pituitary-adrenal axis hyperactivity, disrupted neuronal circuits in several brain regions, increased stress levels, neuroinflammation, and neuronal death. This study will review the psychiatric sequelae in previous coronavirus pandemics, current studies, risk factors, and thorough explanation on pathophysiology of the psychiatric sequalae in COVID-19 survivors.

Delirium occurrence and association with outcomes in hospitalized COVID-19 patients

Delirium is reported to be one of the manifestations of coronavirus infectious disease 2019 (COVID-19) infection. COVID-19 hospitalized patients are at a higher risk of delirium. Pathophysiology behind the association of delirium and COVID-19 is uncertain. We analyzed the association of delirium occurrence with outcomes in hospitalized COVID-19 patients, across all age groups, at Mayo Clinic hospitals.A retrospective study of all hospitalized COVID-19 patients at Mayo Clinic between March 1, 2020 and December 31, 2020 was performed. Occurrence of delirium and outcomes of mortality, length of stay, readmission, and 30-day mortality after hospital discharge were measured. Chi-square test, student t-test, survival analysis, and logistic regression analysis were performed to measure and compare outcomes of delirium group adjusted for age, sex, Charlson comorbidity score, and COVID-19 severity with no-delirium group.A total of 4351 COVID-19 patients were included in the study. Delirium occurrence in the overall study population was noted to be 22.4%. The highest occurrence of delirium was also noted in patients with critical COVID-19 illness severity. A statistically significant OR 4.35 (3.27-5.83) for in-hospital mortality and an OR 4.54 (3.25-6.38) for 30-day mortality after discharge in the delirium group were noted. Increased hospital length of stay, 30-day readmission, and need for skilled nursing facility on discharge were noted in the delirium group. Delirium in hospitalized COVID-19 patients is a marker for increased mortality and morbidity. In this group, outcomes appear to be much worse when patients are older and have a critical severity of COVID-19 illness.

Commentary: Global Alzheimer's disease and Alzheimer's disease related dementia research funding organizations support and engage the research community throughout the COVID-19 pandemic

The COVID‐19 pandemic has disproportionately affected more vulnerable populations, including those living with dementia. Over 50 million individuals worldwide are living with Alzheimer's disease (AD) or other dementia, and it is crucial to continue the fight against the condition during the global pandemic. Since the start of mandated lockdowns in March 2020, charity and non‐profit organizations that fund AD and related dementia research continue to respond to the needs of the AD research community, ensuring the momentum continues and accelerates. Members of the International Alzheimer's and Related Dementia Research Funder Consortium, a group of nearly 40 funding organizations that informally convene throughout the year to share updates and information, have taken a number of steps to ensure the continued support of the research community. Even during times of uncertainty, it is essential that the field moves forward to uncover preventions, diagnoses, and treatments for these diseases that affect many millions globally.

Manifestations and mechanisms of central nervous system damage caused by SARS-CoV-2

The global pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its threat to humans have drawn worldwide attention. The acute and long-term effects of SARS-CoV-2 on the nervous system pose major public health challenges. Patients with SARS-CoV-2 present diverse symptoms of the central nervous system. Exploring the mechanism of coronavirus damage to the nervous system is essential for reducing the long-term neurological complications of COVID-19. Despite rapid progress in characterizing SARS-CoV-2, the long-term effects of COVID-19 on the brain remain unclear. The possible mechanisms of SARS-CoV-2 injury to the central nervous system include: 1) direct injury of nerve cells, 2) activation of the immune system and inflammatory cytokines caused by systemic infection, 3) a high affinity of the SARS-CoV-2 spike glycoprotein for the angiotensin-converting enzyme ACE2, 4) cerebrovascular disease caused by hypoxia and coagulation dysfunction, and 5) a systemic inflammatory response that promotes cognitive impairment and neurodegenerative diseases. Although we do not fully understand the mechanism by which SARS-CoV-2 causes nerve injury, we hope to provide a framework by reviewing the clinical manifestations, complications, and possible mechanisms of neurological damage caused by SARS-CoV-2. With hope, this will facilitate the early identification, diagnosis, and treatment of possible neurological sequelae, which could contribute toward improving patient prognosis and preventing transmission.

The Role of Complement in Synaptic Pruning and Neurodegeneration

The complement system, an essential part of the innate immune system, is composed of a group of secreted and membrane proteins that collectively participate in maintaining the function of the healthy and diseased brain. However, an inappropriate activation of the complement system has been related to an inflammatory response in multiple diseases, such as stroke, traumatic brain injury, multiple sclerosis, and Alzheimer's disease, as well as Zika infection and radiotherapy. In addition, C1q and C3 (initial activation components of the complement cascade) have been shown to play a key beneficial role in the refinement of synaptic circuits during developmental stages and adult plasticity. Nevertheless, excessive synaptic pruning in the adult brain can be detrimental and has been associated with synaptic loss in several pathological conditions. In this brief review, we will discuss the role of the complement system in synaptic pruning as well as its contribution to neurodegeneration and cognitive deficits. We also mention potential therapeutic approaches to target the complement system to treat several neuroinflammatory diseases and unintended consequences of radiotherapy.

Predicting gene regulatory networks from multi-omics to link genetic risk variants and neuroimmunology to Alzheimer's disease phenotypes

BACKGROUND

Genome-wide association studies have found many genetic risk variants associated with Alzheimer's disease (AD). However, how these risk variants affect deeper phenotypes such as disease progression and immune response remains elusive. Also, our understanding of cellular and molecular mechanisms from disease risk variants to various phenotypes is still limited. To address these problems, we performed an integrative multi-omics analysis of genotype, transcriptomics, and epigenomics for revealing gene regulatory mechanisms from disease variants to AD phenotypes.

METHOD

First, given the population gene expression data of a cohort, we construct and cluster its gene co-expression network to identify gene co-expression modules for various AD phenotypes. Next, we predict transcription factors (TFs) regulating co-expressed genes and AD risk SNPs that interrupt TF binding sites on regulatory elements. Finally, we construct a gene regulatory network (GRN) linking SNPs, interrupted TFs, and regulatory elements to target genes and gene modules for each phenotype in the cohort. This network thus provides systematic insights into gene regulatory mechanisms from risk variants to AD phenotypes.

RESULTS

Our analysis predicted GRNs in three major AD-relevant regions: Hippocampus, Dorsolateral Prefrontal Cortex (DLPFC), Lateral Temporal Lobe (LTL). Comparative analyses revealed cross-region-conserved and region-specific GRNs, in which many immunological genes are present. For instance, SNPs rs13404184 and rs61068452 disrupt SPI1 binding and regulation of AD gene INPP5D in the Hippocampus and LTL. However, SNP rs117863556 interrupts bindings of REST to regulate GAB2 in DLPFC only. Driven by emerging neuroinflammation in AD, we used Covid-19 as a proxy to identify possible regulatory mechanisms for neuroimmunology in AD. To this end, we looked at the GRN subnetworks relating to genes from shared AD-Covid pathways. From those subnetworks, our machine learning analysis prioritized the AD-Covid genes for predicting Covid-19 severity. Decision Curve Analysis also validated our AD-Covid genes outperform known Covid-19 genes for classifying severe Covid-19 patients. This suggests AD-Covid genes along with linked SNPs can be potential novel biomarkers for neuroimmunology in AD. Finally, our results are open-source available as a comprehensive functional genomic map for AD, providing a deeper mechanistic understanding of the interplay among multi-omics, brain regions, gene functions like neuroimmunology, and phenotypes.

A Framework for Addressing Clients' Functional Cognitive Deficits After COVID-19

Occupational therapy's focus on functional cognition offers a distinct approach to the assessment of and intervention for occupational performance deficits that may follow coronavirus disease 2019 (COVID-19). Although the majority of people survive COVID-19, many people experience persistent functional cognitive sequelae severe enough to interfere with occupational performance. After COVID-19, people may be categorized as either (1) those who experience severe or critical illness requiring hospitalization or (2) those with mild to moderate presentations of the virus without hospitalization. A third group of those who do not have ongoing signs of active infection but who experience new, lasting, or deteriorating symptoms has begun to emerge and may represent a distinct COVID-19 long-haul syndrome. By following the Occupational Therapy Practice Framework and using established processes for occupational therapy assessment and treatment of functional cognition, occupational therapy practitioners can tailor assessments and interventions to meet clients' needs.

[Neuropsychiatric Aspects of COVID-19 - A Narrative Overview]

The SARS-CoV-2 virus (Severe Acute Respiratory Syndrome Coronavirus Type 2) and COVID-19 (Coronavirus Disease 2019) can affect numerous organ systems. In the present paper we offer an overview of the current state of knowledge about the psychiatric aspects of SARS-CoV-2 infection.Medline, Embase und LIVIVO were searched for relevant literature, the last query dating from March 2nd, 2021. Different stress factors in the context of the pandemic can lead to manifest mental illnesses. In addition, there is a risk of neuropsychological changes due to the biological effects of the virus itself.Our work describes the psychological symptoms of COVID-19 sufferers themselves and the psychological effects of the epidemic and the associated socio-economic and psychosocial stress factors on those who are not sick.The most common psychiatric complication among people with COVID-19 is delirium, while hospitalized patients seem to have an increased incidence of symptoms of anxiety, depression and PTSD. There are many case reports on psychotic disorders. In general, an existing psychiatric illness (especially dementia and psychotic disorders) also increases the risk of infection and of a more severe course of the disease. After recovery from COVID-19 infection, there is also a higher incidence of mental illnesses, in particular "Chronic Post-SARS Syndrome" with its manifestations such as fatigue, anxiety, depression and PTSD. In addition, the course of dementia seems to be negatively influenced by an infection with SARS-CoV-2.The second part deals with the effects of the epidemic as a stressor and the established socio-political measures on the mental health of people with and without previous mental illnesses. The literature currently available shows high symptom values for anxiety and depressive disorders as well as post-traumatic stress disorders, stress, suicidality, sleep disorders etc. Risk factors seem to include female gender, younger age and fewer resources, as well as previous psychiatric or physical illnesses. Extrinsic factors such as high infection rates, large numbers of deaths, long curfews/lockdowns, low trust in the government and ineffective measures against economic and social consequences increase the burden.

Post-covid syndrome: a review of pathophysiology, neuropsychiatric manifestations and treatment perspectives

In the context of the COVID-19 pandemic, healthcare is faced with several new problems, one of which is a post-covid syndrome. Symptoms in many COVID-19 survivors can persist for a long time, significantly affecting the quality of life and work performance. All of the above makes post-covid syndrome a socially significant disease, requires dynamic follow-up of such patients, and rehabilitation programs development. We are currently at the stage of accumulating knowledge about the SARS-CoV-2 pathophysiology and morphogenesis and its long-term consequences. This article discusses neuropsychiatric aspects of the post-covid syndrome: pathogenetic hypotheses, clinical features, and potentially promising treatment strategies.

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

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

Network medicine links SARS-CoV-2/COVID-19 infection to brain microvascular injury and neuroinflammation in dementia-like cognitive impairment

BACKGROUND

Dementia-like cognitive impairment is an increasingly reported complication of SARS-CoV-2 infection. However, the underlying mechanisms responsible for this complication remain unclear. A better understanding of causative processes by which COVID-19 may lead to cognitive impairment is essential for developing preventive and therapeutic interventions.

METHODS

In this study, we conducted a network-based, multimodal omics comparison of COVID-19 and neurologic complications. We constructed the SARS-CoV-2 virus-host interactome from protein-protein interaction assay and CRISPR-Cas9-based genetic assay results and compared network-based relationships therein with those of known neurological manifestations using network proximity measures. We also investigated the transcriptomic profiles (including single-cell/nuclei RNA-sequencing) of Alzheimer's disease (AD) marker genes from patients infected with COVID-19, as well as the prevalence of SARS-CoV-2 entry factors in the brains of AD patients not infected with SARS-CoV-2.

RESULTS

We found significant network-based relationships between COVID-19 and neuroinflammation and brain microvascular injury pathways and processes which are implicated in AD. We also detected aberrant expression of AD biomarkers in the cerebrospinal fluid and blood of patients with COVID-19. While transcriptomic analyses showed relatively low expression of SARS-CoV-2 entry factors in human brain, neuroinflammatory changes were pronounced. In addition, single-nucleus transcriptomic analyses showed that expression of SARS-CoV-2 host factors (BSG and FURIN) and antiviral defense genes (LY6E, IFITM2, IFITM3, and IFNAR1) was elevated in brain endothelial cells of AD patients and healthy controls relative to neurons and other cell types, suggesting a possible role for brain microvascular injury in COVID-19-mediated cognitive impairment. Overall, individuals with the AD risk allele APOE E4/E4 displayed reduced expression of antiviral defense genes compared to APOE E3/E3 individuals.

CONCLUSION

Our results suggest significant mechanistic overlap between AD and COVID-19, centered on neuroinflammation and microvascular injury. These results help improve our understanding of COVID-19-associated neurological manifestations and provide guidance for future development of preventive or treatment interventions, although causal relationship and mechanistic pathways between COVID-19 and AD need future investigations.

Neuromodulatory effects of SARS-CoV2 infection: Possible therapeutic targets

INTRODUCTION

Although SARS-CoV-2 primarily manifests in the form of respiratory symptoms, emerging evidence suggests that the disease is associated with numerous neurological complications, such as stroke and Guillain-Barre syndrome. Hence, further research is necessary to seek possible therapeutic targets in the CNS for effective management of these complications.

AREAS COVERED

This review examines the neurological complications associated with SARS-CoV-2 infections and the possible routes of infection. It progresses to illuminate the possible therapeutic targets for effective management of these neuromodulatory effects and the repurposing of drugs that could serve this purpose. To this end, literature from the year 1998-2021 was derived from PubMed.

EXPERT OPINION

The neurological manifestations associated with COVID-19 may be related to poor prognosis and higher comorbidity. Identification of the key molecular targets in the brain that are potential indicators of the observed neuropathology, such as inflammatory mediators and chromatin modifiers, is key. The repurposing of existing drugs to target potential candidates could reduce the mortality attributed to these associated neurological complications.

Network medicine links SARS-CoV-2/COVID-19 infection to brain microvascular injury and neuroinflammation in dementia-like cognitive impairment

BACKGROUND

Dementia-like cognitive impairment is an increasingly reported complication of SARS-CoV-2 infection. However, the underlying mechanisms responsible for this complication remain unclear. A better understanding of causative processes by which COVID-19 may lead to cognitive impairment is essential for developing preventive interventions.

METHODS

In this study, we conducted a network-based, multimodal genomics comparison of COVID-19 and neurologic complications. We constructed the SARS-CoV-2 virus-host interactome from protein-protein interaction assay and CRISPR-Cas9 based genetic assay results, and compared network-based relationships therein with those of known neurological manifestations using network proximity measures. We also investigated the transcriptomic profiles (including single-cell/nuclei RNA-sequencing) of Alzheimer's disease (AD) marker genes from patients infected with COVID-19, as well as the prevalence of SARS-CoV-2 entry factors in the brains of AD patients not infected with SARS-CoV-2.

RESULTS

We found significant network-based relationships between COVID-19 and neuroinflammation and brain microvascular injury pathways and processes which are implicated in AD. We also detected aberrant expression of AD biomarkers in the cerebrospinal fluid and blood of patients with COVID-19. While transcriptomic analyses showed relatively low expression of SARS-CoV-2 entry factors in human brain, neuroinflammatory changes were pronounced. In addition, single-nucleus transcriptomic analyses showed that expression of SARS-CoV-2 host factors ( BSG and FURIN ) and antiviral defense genes ( LY6E , IFITM2 , IFITM3 , and IFNAR1 ) was significantly elevated in brain endothelial cells of AD patients and healthy controls relative to neurons and other cell types, suggesting a possible role for brain microvascular injury in COVID-19-mediated cognitive impairment. Notably, individuals with the AD risk allele APOE E4/E4 displayed reduced levels of antiviral defense genes compared to APOE E3/E3 individuals.

CONCLUSION

Our results suggest significant mechanistic overlap between AD and COVID-19, strongly centered on neuroinflammation and microvascular injury. These results help improve our understanding of COVID-19-associated neurological manifestations and provide guidance for future development of preventive or treatment interventions.

Interactions of SARS-CoV-2 with the Blood-Brain Barrier

Emerging data indicate that neurological complications occur as a consequence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The blood-brain barrier (BBB) is a critical interface that regulates entry of circulating molecules into the CNS, and is regulated by signals that arise from the brain and blood compartments. In this review, we discuss mechanisms by which SARS-CoV-2 interactions with the BBB may contribute to neurological dysfunction associated with coronavirus disease of 2019 (COVID-19), which is caused by SARS-CoV-2. We consider aspects of peripheral disease, such as hypoxia and systemic inflammatory response syndrome/cytokine storm, as well as CNS infection and mechanisms of viral entry into the brain. We also discuss the contribution of risk factors for developing severe COVID-19 to BBB dysfunction that could increase viral entry or otherwise damage the brain.

COVID-19 and Alzheimer's Disease

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a neurotropic virus with a high neuroinvasive potential. Indeed, more than one-third of patients develop neurological symptoms, including confusion, headache, and hypogeusia/ageusia. However, long-term neurological consequences have received little interest compared to respiratory, cardiovascular, and renal manifestations. Several mechanisms have been proposed to explain the potential SARS-CoV-2 neurological injury that could lead to the development of neurodegenerative diseases, including Alzheimer's Disease (AD). A mutualistic relationship between AD and COVID-19 seems to exist. On the one hand, COVID-19 patients seem to be more prone to developing AD. On the other hand, AD patients could be more susceptible to severe COVID-19. In this review, we sought to provide an overview on the relationship between AD and COVID-19, focusing on the potential role of biomarkers, which could represent precious tool for early identification of COVID-19 patients at high risk of developing AD.