Coronaviruses and Central Nervous System Manifestations

Neurons cytoskeletal architecture remodeling during the replication cycle of mouse coronavirus MHV-JHM: a morphological in vitro study

Nowadays, the population is still struggling with a post-COVID19 syndrome known as long COVID, including a broad spectrum of neurological problems. There is an urgent need for a better understanding and exploration of the mechanisms of coronavirus neurotropism. For this purpose, the neurotropic strain of mouse hepatitis virus (MHV-JHM) originating from the beta-coronavirus genus, the same as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been used. The role of the cytoskeleton during virus replication in neurons in vitro was determined to understand the mechanisms of MHV-JHM neuroinfection. We have described for the first time the changes of actin filaments during MHV-JHM infection. We also observed productive replication of MHV-JHM in neurons during 168 h p.i. and syncytial cytopathic effect. We discovered that the MHV-JHM strain modulated neuronal cytoskeleton during infection, which were manifested by: (i) condensation of actin filaments in the cortical layer of the cytoplasm, (ii) formation of microtubule cisternae structures containing viral antigen targeting viral replication site (iii) formation of tunneling nanotubes used by MHV-JHM for intercellular transport. Additionally, we demonstrated that the use of cytoskeletal inhibitors have reduced virus replication in neurons, especially noscapine and nocodazole, the microtubule shortening factors.

Highlighting the Neuropsychological Consequences of COVID-19: Evidence From a Narrative Review

The coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2, although largely affecting the respiratory system, commonly presents with numerous clinical symptoms from other systems. COVID-19 has been associated with both acute and persistent neurological abnormalities in a substantial proportion of patients. Notably, post-COVID-19 neuropsychological abnormalities have garnered attention, highlighting a high prevalence of neurocognitive issues in affected individuals. This narrative review synthesizes current knowledge on the neuropsychological impact of COVID-19, drawing insights from an extensive online search of published literature conducted in the PubMed (MEDLINE) and Scopus databases. The findings underscore significant neuropsychological effects of COVID-19 observed at both individual and societal levels during the ongoing pandemic. Neuropsychological deficits such as memory difficulties, attention problems, and executive dysfunction, alongside physical symptoms like headaches and fatigue were commonly reported. Additionally, psychological challenges, including fear, anxiety, and depression, emerged as prevalent issues arising from the uncertainties surrounding the situation, social isolation, and employment insecurities. The identified neuropsychological manifestations of COVID-19 can significantly impede normal cognitive and emotional functioning, potentially resulting in decreased productivity and an overall decline in mental health and quality of life. Early identification of signs indicative of neurological or psychological decline becomes imperative, offering a crucial opportunity to mitigate the risk of long-term neuropsychological dysfunction through the development of targeted interventions.

A review of the mechanisms of blood-brain barrier disruption during COVID-19 infection

Coronaviruses are prevalent in mammals and birds, including humans and bats, and they often spread through airborne droplets. In humans, these droplets then interact with angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2), which are the main receptors for the SARS-CoV-2 virus. It can infect several organs, including the brain. The blood-brain barrier (BBB) is designed to maintain the homeostatic neural microenvironment of the brain, which is necessary for healthy neuronal activity, function, and stability. It prevents viruses from entering the brain parenchyma and does not easily allow chemicals to pass into the brain while assisting numerous compounds in exiting the brain. The purpose of this review was to examine how COVID-19 influences the BBB along with the mechanisms that indicate the BBB's deterioration. In addition, the cellular mechanism through which SARS-CoV-2 causes BBB destruction by binding to ACE2 was evaluated and addressed. The mechanisms of the immunological reaction that occurs during COVID-19 infection that may contribute to the breakdown of the BBB were also reviewed. It was discovered that the integrity of the tight junction (TJs), basement membrane, and adhesion molecules was damaged during COVID-19 infection, which led to the breakdown of the BBB. Therefore, understanding how the BBB is disrupted by COVID-19 infection will provide an indication of how the SARS-CoV-2 virus is able to reach the central nervous system (CNS). The findings of this research may help in the identification of treatment options for COVID-19 that can control and manage the infection.

Altered intrinsic brain activity and functional connectivity in COVID-19 hospitalized patients at 6-month follow-up

BACKGROUND

Although most patients can recover from SARS-CoV-2 infection during the short-term, the long-term effects of COVID-19 on the brain remain explored. Functional MRI (fMRI) could potentially elucidate or otherwise contribute to the investigation of the long COVID syndrome. A lower fMRI response would be translated into decreased brain activity or delayed signal transferring reflecting decreased connectivity. This research aimed to investigate the long-term alterations in the local (regional) brain activity and remote (interregional) functional connection in recovered COVID-19.

METHODS

Thirty-five previously hospitalized COVID-19 patients underwent 3D T1weighed imaging and resting-state fMRI at 6-month follow-up, and 36 demographic-matched healthy controls (HCs) were recruited accordingly. The amplitude of low-frequency fluctuation (ALFF) and seed-based functional connectivity (FC) was used to assess the regional intrinsic brain activity and the influence of regional disturbances on FC with other brain regions. Spearman correlation analyses were performed to evaluate the association between brain function changes and clinical variables.

RESULTS

The incidence of neurosymptoms (6/35, 17.14%) decreased significantly at 6-month follow-up, compared with COVID-19 hospitalization stage (21/35, 60%). Compared with HCs, recovered COVID-19 exhibited higher ALFF in right precuneus, middle temporal gyrus, middle and inferior occipital gyrus, lower ALFF in right middle frontal gyrus and bilateral inferior temporal gyrus. Furthermore, setting seven abnormal activity regions as seeds, we found increased FC between right middle occipital gyrus and left inferior occipital gyrus, and reduced FC between right inferior occipital gyrus and right inferior temporal gyrus/bilateral fusiform gyrus, and between right middle frontal gyrus and right middle frontal gyrus/ supplementary motor cortex/ precuneus. Additionally, abnormal ALFF and FC were associated with clinical variables.

CONCLUSIONS

COVID-19 related neurological symptoms can self heal over time. Recovered COVID-19 presented functional alterations in right frontal, temporal and occipital lobe at 6-month follow-up. Most regional disturbances in ALFF were related to the weakening of short-range regional interactions in the same brain function.

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.

SARS-COV-2 a trigger of myelin oligodendrocyte glycoprotein-associated disorder

SARS-COV-2 frequently cause neurological disorders and is sometimes associated with onset of autoimmune diseases affecting the nervous system. Over recent years, a rare but distinct diagnosis designated myelin oligodendrocyte glycoprotein-associated disorder (MOGAD) has been recognized in patients with attacks of optic neuritis, myelitis, or encephalomyelitis and increased levels of anti-MOG antibodies. The cause of MOGAD is unknown. However, there have been reports of single cases of MOGAD in patients with Covid-19 infection. We report a series of SARS-CoV-2 positive patients that developed MOGAD, but a homology search did not support a cross-reactive immune response to SARS-CoV-2 spike-protein and MOG.

The potential impact of Covid-19 on CNS and psychiatric sequels

Due to its high prevalence and fatality, the current Severe Acute Respiratory Syndrome-coronavirus-2 (SARS-CoV-2) virus, which first emerged in China in 2019, quickly spread around the world and immediately became a serious global health concern. Although respiratory issues were initially the most prominent symptom of coronavirus disease 2019 (COVID-19), it became obvious rapidly that COVID-19, like many other coronavirus family members, could affect the central nervous system (CNS). During the pandemic, CNS involvement expressed itself in a variety of forms, including insomnia, anosmia, headaches, encephalopathies, encephalitis, cerebrovascular accidents, cognitive and memory impairment, and increased psychiatric disorders. Almost everyone who has been infected has at least one of these neurological symptoms, demonstrating that the virus has a high ability to impact the CNS. As the coronavirus pandemic passes its second year, the manifestations it can cause in the long run, such as its psychological sequels, have not yet been thoroughly studied. Given the high importance of this issue in today's society and due to the lack of reliable knowledge about the COVID-19 landscape on psychiatric disorders, we intend to investigate coronavirus's possible effect on mental illnesses based on available literature. Because the majority of the psychological effects of the coronavirus can continue for a long period after the pandemic ends, our research can give insight into potential psychiatric sequels associated with COVID-19.

Microglia in antiviral immunity of the brain and spinal cord

Viral infections of the central nervous system (CNS) are a significant cause of neurological impairment and mortality worldwide. As tissue resident macrophages, microglia are critical initial responders to CNS viral infection. Microglia seem to coordinate brain-wide antiviral responses of both brain resident cells and infiltrating immune cells. This review discusses how microglia may promote this antiviral response at a molecular level, from potential mechanisms of virus recognition to downstream cytokine responses and interaction with antiviral T cells. Recent advancements in genetic tools to specifically target microglia in vivo promise to further our understanding about the precise mechanistic role of microglia in CNS infection.

Pathomechanisms and Treatment Implications for Stroke in COVID-19: A Review of the Literature

Stroke in patients with COVID-19 has received increasing attention throughout the global COVID-19 pandemic, perhaps due to the substantial disability and mortality that can result when the two conditions co-occur. We reviewed the existing literature and found that the proposed pathomechanism underlying COVID-19-associated ischemic stroke is broadly divided into the following three categories: vasculitis, endothelialitis, and endothelial dysfunction; hypercoagulable state; and cardioembolism secondary to cardiac dysfunction. There has been substantial debate as to whether there is a causal link between stroke and COVID-19. However, the distinct phenotype of COVID-19-associated strokes, with multivessel territory infarcts, higher proportion of large vessel occlusions, and cryptogenic stroke mechanism, that emerged in pooled analytic comparisons with non-COVID-19 strokes is compelling. Further, in this article, we review the various treatment approaches that have emerged as they relate to the proposed pathomechanisms. Finally, we briefly cover the logistical challenges, such as delays in treatment, faced by providers and health systems; the innovative approaches utilized, including the role of tele-stroke; and the future directions in COVID-19-associated stroke research and healthcare delivery.

B cells in central nervous system disease: diversity, locations and pathophysiology

B cells represent a relatively minor cell population within both the healthy and diseased central nervous system (CNS), yet they can have profound effects. This is emphasized in multiple sclerosis, in which B cell-depleting therapies are arguably the most efficacious treatment for the condition. In this Review, we discuss how B cells enter and persist in the CNS and how, in many neurological conditions, B cells concentrate within CNS barriers but are rarely found in the parenchyma. We highlight how B cells can contribute to CNS pathology through antibody secretion, antigen presentation and secretion of neurotoxic molecules, using examples from CNS tumours, CNS infections and autoimmune conditions such as neuromyelitis optica and, in particular, multiple sclerosis. Overall, understanding common and divergent principles of B cell accumulation and their effects within the CNS could offer new insights into treating these devastating neurological conditions.

SARS-CoV-2-Mediated Neuropathogenesis, Deterioration of Hippocampal Neurogenesis and Dementia

A significant portion of COVID-19 patients and survivors display marked clinical signs of neurocognitive impairments. SARS-CoV-2-mediated peripheral cytokine storm and its neurotropism appear to elicit the activation of glial cells in the brain proceeding to neuroinflammation. While adult neurogenesis has been identified as a key cellular basis of cognitive functions, neuroinflammation-induced aberrant neuroregenerative plasticity in the hippocampus has been implicated in progressive memory loss in ageing and brain disorders. Notably, recent histological studies of post-mortem human and experimental animal brains indicate that SARS-CoV-2 infection impairs neurogenic process in the hippocampus of the brain due to neuroinflammation. Considering the facts, this article describes the prominent neuropathogenic characteristics and neurocognitive impairments in COVID-19 and emphasizes a viewpoint that neuroinflammation-mediated deterioration of hippocampal neurogenesis could contribute to the onset and progression of dementia in COVID-19. Thus, it necessitates the unmet need for regenerative medicine for the effective management of neurocognitive deficits in COVID-19.

COVID-19, the Brain, and the Future: Is Infection by the Novel Coronavirus a Harbinger of Neurodegeneration?

The possible impact of viral infections on the development or pathogenesis of neurodegenerative disorders remains largely unknown. However, there have been reports associating the influenza virus pandemic and long-term infection with the Japanese encephalitis virus with the development of post-encephalitic Parkinsonism or von Economo encephalitis. In the last one year plus, there has been a worldwide pandemic arising from infection with the novel coronavirus or severe acute respiratory syndrome coronavirus (SARS-CoV)-2 which causes a severe acute respiratory syndrome that has become associated with central nervous system symptoms or complications. Its possible central nervous system involvement is in line with emerging scientific evidence which shows that the human respiratory coronaviruses can enter the brain, infect neural cells, persist in the brain, and cause activation of myelin-reactive T cells. Currently, there is a dearth of scientific information on the acute or possible long-term impact of infection with SARS-CoV-2 on the development of dementias and/or neurodegenerative diseases. This is not unrelated to the fact that the virus is 'new', and its effects on humans are still being studied. This narrative review examines extant literature for the impact of corona virus infections on the brain; as it considers the possibility that coronavirus disease 2019 (COVID-19) could increase the risk for the development of neurodegenerative diseases or hasten their progression.

Long COVID: "And the fire rages on"

With the increasing cohort of COVID-19 survivors worldwide, we now realize the proportionate rise in post-COVID-19 syndrome. In this review article, we try to define, summarize, and classify this syndrome systematically. This would help clinicians to identify and manage this condition more efficiently. We propose a tool kit that might be useful in recording follow-up data of COVID-19 survivors.

Can Covid-19 attack our nervous system?

Nowadays, Covid-19 is considered a serious health problem worldwide. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel human coronavirus that has sparked a global pandemic of the coronavirus disease of 2019 (COVID-19). It is well known that the Corona Virus attacks mainly the respiratory system. Meanwhile, it has been established that coronavirus infection can extend beyond the respiratory system and unfortunately, can also affect our nervous system. Multiple neurological symptoms and signs had been documented during and post covid conditions. This virus gets access to the central nervous system (CNS) via the bloodstream leading to infect the endothelial lining cells. Also, it was reported that the virus can enter the peripheral nervous system via retrograde neuronal routes. The virus could be internalized in nerve synapses through endocytosis, transported retrogradely, and spread trans-synoptically to other brain regions. This minireview highlights the possible routes by which SARS-CoV-2 can invade the central nervous system (CNS) and its pathophysiology and manifestation.

Microglial Implications in SARS-CoV-2 Infection and COVID-19: Lessons From Viral RNA Neurotropism and Possible Relevance to Parkinson's Disease

Since December 2019, humankind has been experiencing a ravaging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak, the second coronavirus pandemic in a decade after the Middle East respiratory syndrome coronavirus (MERS-CoV) disease in 2012. Infection with SARS-CoV-2 results in Coronavirus disease 2019 (COVID-19), which is responsible for over 3.1 million deaths worldwide. With the emergence of a second and a third wave of infection across the globe, and the rising record of multiple reinfections and relapses, SARS-CoV-2 infection shows no sign of abating. In addition, it is now evident that SARS-CoV-2 infection presents with neurological symptoms that include early hyposmia, ischemic stroke, meningitis, delirium and falls, even after viral clearance. This may suggest chronic or permanent changes to the neurons, glial cells, and/or brain vasculature in response to SARS-CoV-2 infection or COVID-19. Within the central nervous system (CNS), microglia act as the central housekeepers against altered homeostatic states, including during viral neurotropic infections. In this review, we highlight microglial responses to viral neuroinfections, especially those with a similar genetic composition and route of entry as SARS-CoV-2. As the primary sensor of viral infection in the CNS, we describe the pathogenic and neuroinvasive mechanisms of RNA viruses and SARS-CoV-2 vis-à-vis the microglial means of viral recognition. Responses of microglia which may culminate in viral clearance or immunopathology are also covered. Lastly, we further discuss the implication of SARS-CoV-2 CNS invasion on microglial plasticity and associated long-term neurodegeneration. As such, this review provides insight into some of the mechanisms by which microglia could contribute to the pathophysiology of post-COVID-19 neurological sequelae and disorders, including Parkinson's disease, which could be pervasive in the coming years given the growing numbers of infected and re-infected individuals globally.

COVID-19 and emerging spinal cord complications: A systematic review

BACKGROUND

Spinal cord complications associated with coronavirus infectious disease of 2019 (COVID-19) are being widely reported. The purpose of this systematic review was to summarize so far available pieces of evidence documenting de novo novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) mediated spinal cord demyelinating diseases. Indeed, the spinal demyelinating disorders that have been reported in those patients who have suffered from COVID-19 rather than on the people already living with diagnosed or undiagnosed primary demyelinating disorders.

METHODS

We used the existing PRISMA consensus statement. Data were collected from PubMed, NIH Litcovid, EMBASE and Cochrane library databases, as well as Pre-print servers (medRxiv, bioRxiv, and pre-preints.org), until September 10, 2020, using pre-specified searching strategies.

RESULTS

The 21 selected articles were all case reports and included 11 (52%) men and 10 (48%) women. The mean age was of 46.7 ± 18.0. The neurological manifestations included weakness, sensory deficit, autonomic dysfunction and ataxia. In most cases, elevated cerebrospinal fluid protein as well as lymphocytic pleocytosis were found. SARS-CoV-2 was detected in five (24%) patients, meanwhile in 13 (62%) patients, the testing was negative. Testing was not performed in two cases and, in one, data were unavailable. Nearly half of the cases (N = 9) were associated with isolated long extensive transverse myelitis (LETM), whereas a combination of both LETM and patchy involvement was found in two. Only five patients had isolated short segment involvement and two patchy involvement. Furthermore, concomitant demyelination of both brain and spine was reported in six patients. Concerning the prognosis, most of the patients improved and the mortality rate was low (N = 2, <10%).

CONCLUSION

Spinal cord demyelination should be added to the plethora of immune mediated neurologic complications associated with COVID-19.

Biomaterial-based immunoengineering to fight COVID-19 and infectious diseases

Infection by SARS-CoV-2 virus often induces the dysregulation of immune responses, tissue damage, and blood clotting. Engineered biomaterials from the nano- to the macroscale can provide targeted drug delivery, controlled drug release, local immunomodulation, enhanced immunity, and other desirable functions to coordinate appropriate immune responses and to repair tissues. Based on the understanding of COVID-19 disease progression and immune responses to SARS-CoV-2, we discuss possible immunotherapeutic strategies and highlight biomaterial approaches from the perspectives of preventive immunization, therapeutic immunomodulation, and tissue healing and regeneration. Successful development of biomaterial platforms for immunization and immunomodulation will not only benefit COVID-19 patients, but also have broad applications for a variety of infectious diseases.

Unexpected worsening of progressive multifocal leucoencephalopathy following COVID-19 pneumonia

Progressive multifocal leucoencephalopathy is a serious side effect of natalizumab, a humanized monoclonal antibody approved for the treatment of multiple sclerosis. Here, we report a case of unexpected worsening of natalizumab-related progressive multifocal leucoencephalopathy following COVID-19. After natalizumab discontinuation, a slight neurological improvement was observed, but, two months later the patient was admitted to the hospital because of neurological deterioration and COVID-19 mild pneumonia. Except for SARS-CoV-2 infection, no other potential factors of neurological worsening were identified. Thus, we pose the hypothesis that SARS-CoV-2 was instrumental in the progressive multifocal leucoencephalopathy deterioration.

COVID-19 vasculitis and novel vasculitis mimics

COVID-19 has been occasionally linked to histologically confirmed cutaneous vasculitis and a Kawasaki-like vasculitis, with these entities generally having minimal or no lung involvement and a good prognosis. Unlike these vasculitis types, patients with severe COVID-19 pneumonia can develop cutaneous vasculitis-like lesions and systemic arterial and venous thromboemboli, including cryptogenic strokes and other vasculopathy features. Proposed underlying mechanisms for these severe manifestations have encompassed immune dysregulation, including an anti-phospholipid syndrome-like state, complement activation, viral dissemination with direct systemic endothelial infection, viral RNAaemia with immunothrombosis, clotting pathway activation mediated by hypoxaemia, and immobility. In this Viewpoint, we highlight how imaging and post-mortem findings from patients with COVID-19 indicate a novel thrombosis in the pulmonary venous territory distal to the alveolar capillary bed, a territory that normally acts as a clot filtration system, which might represent an unappreciated nidus for systemic microembolism. Additionally, we suggest that this mechanism represents a novel vasculitis mimic related to COVID-19 that might lead to cryptogenic strokes across multivessel territories, acute kidney injury with haematuria, a skin vasculitis mimic, intestinal ischaemia, and other organ ischaemic manifestations. This finding is supported by pathological reports of extensive pulmonary venular thrombosis and peripheral organ thrombosis with pauci-immune cellular infiltrates. Therefore, severe COVID-19 pneumonia with extensive pulmonary intravascular coagulopathy might help to explain the numerous systemic complications of COVID-19, in which the demonstration of direct organ infection has not adequately explained the pathology.

The Impact of SARS-CoV-2 Infection on the Development of Neurodegeneration in Multiple Sclerosis

The novel coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global challenge. Currently, there is some information on the consequences of COVID-19 infection in multiple sclerosis (MS) patients, as it is a newly discovered coronavirus, but its far-reaching effects on participation in neurodegenerative diseases seem to be significant. Recent cases reports showed that SARS-CoV-2 may be responsible for initiating the demyelination process in people who previously had no symptoms associated with any nervous system disorders. It is presently known that infection of SARS-CoV-2 evokes cytokine storm syndrome, which may be one of the factors leading to the acute cerebrovascular disease. One of the substantial problems is the coexistence of cerebrovascular disease and MS in an individual's life span. Epidemiological studies showed an enhanced risk of death rate from vascular disabilities in MS patients of approximately 30%. It has been demonstrated that patients with severe SARS-CoV-2 infection usually show increased levels of D-dimer, fibrinogen, C-reactive protein (CRP), and overactivation of blood platelets, which are essential elements of prothrombotic events. In this review, the latest knowledge gathered during an ongoing pandemic of SARS-CoV-2 infection on the neurodegeneration processes in MS is discussed.

18F-FDG brain PET hypometabolism in patients with long COVID

PURPOSE

In the context of the worldwide outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), some patients report functional complaints after apparent recovery from COVID-19. This clinical presentation has been referred as "long COVID." We here present a retrospective analysis of ¹⁸F-FDG brain PET of long COVID patients from the same center with a biologically confirmed diagnosis of SARS-CoV-2 infection and persistent functional complaints at least 3 weeks after the initial infection.

METHODS

PET scans of 35 patients with long COVID were compared using whole-brain voxel-based analysis to a local database of 44 healthy subjects controlled for age and sex to characterize cerebral hypometabolism. The individual relevance of this metabolic profile was evaluated to classify patients and healthy subjects. Finally, the PET abnormalities were exploratory compared with the patients' characteristics and functional complaints.

RESULTS

In comparison to healthy subjects, patients with long COVID exhibited bilateral hypometabolism in the bilateral rectal/orbital gyrus, including the olfactory gyrus; the right temporal lobe, including the amygdala and the hippocampus, extending to the right thalamus; the bilateral pons/medulla brainstem; the bilateral cerebellum (p-voxel < 0.001 uncorrected, p-cluster < 0.05 FWE-corrected). These metabolic clusters were highly discriminant to distinguish patients and healthy subjects (100% correct classification). These clusters of hypometabolism were significantly associated with more numerous functional complaints (brainstem and cerebellar clusters), and all associated with the occurrence of certain symptoms (hyposmia/anosmia, memory/cognitive impairment, pain and insomnia) (p < 0.05). In a more preliminary analysis, the metabolism of the frontal cluster which included the olfactory gyrus was worse in the 7 patients treated by ACE drugs for high blood pressure (p = 0.032), and better in the 3 patients that had used nasal decongestant spray at the infectious stage (p < 0.001).

CONCLUSION

This study demonstrates a profile of brain PET hypometabolism in long COVID patients with biologically confirmed SARS-CoV-2 and persistent functional complaints more than 3 weeks after the initial infection symptoms, involving the olfactory gyrus and connected limbic/paralimbic regions, extended to the brainstem and the cerebellum. These hypometabolisms are associated with patients' symptoms, with a biomarker value to identify and potentially follow these patients. The hypometabolism of the frontal cluster, which included the olfactory gyrus, seems to be linked to ACE drugs in patients with high blood pressure, with also a better metabolism of this olfactory region in patients using nasal decongestant spray, suggesting a possible role of ACE receptors as an olfactory gateway for this neurotropism.

Report of the Academy of Consultation-Liaison Psychiatry Task Force on Lessons Learned From the COVID-19 Pandemic: Executive Summary

BACKGROUND

The COVID-19 pandemic forced consultation-liaison psychiatrists to adapt to unprecedented circumstances. The Academy of Consultation-Liaison Psychiatry (ACLP) recognized the need and opportunity to assess its response and convened a task force in mid-2020 to review the lessons learned from the initial experience of the COVID-19 pandemic.

OBJECTIVE

The aim of the study was to summarize experience and make recommendations to the ACLP Board of Directors about potential ACLP directions related to current and future pandemic response.

METHODS

In August-November 2020, the task force reviewed local experiences, ACLP list-serv contributions, and the published literature and generated recommendations for ACLP actions.

RESULTS

Recommendations addressed telepsychiatry, hospital staff wellness, support for consultation-liaison psychiatrists, the need for additional research on psychiatric and neuropsychiatric aspects of COVID-19, and the ACLP's role in advocacy and dissemination of information. The task force report was submitted to the ACLP Board of Directors in November 2020.

CONCLUSIONS

As the preeminent organization of consultation-liaison psychiatrists, the ACLP can implement actions related to pandemic awareness and preparedness for the benefit of consultation-liaison psychiatrists, other health care workers, patients, and the general population.

COVID-19 and multiorgan failure: A narrative review on potential mechanisms

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) in December 2019 form Wuhan, China leads to coronavirus disease 2019 (COVID-19) pandemic. While the common cold symptoms are observed in mild cases, COVID-19 is accompanied by multiorgan failure in severe patients. The involvement of different organs in severe patients results in lengthening the hospitalization duration and increasing the mortality rate. In this review, we aimed to investigate the involvement of different organs in COVID-19 patients, particularly in severe cases. Also, we tried to define the potential underlying mechanisms of SARS-CoV2 induced multiorgan failure. The multi-organ dysfunction is characterized by acute lung failure, acute liver failure, acute kidney injury, cardiovascular disease, and as well as a wide spectrum of hematological abnormalities and neurological disorders. The most important mechanisms are related to the direct and indirect pathogenic features of SARS-CoV2. Although the presence of angiotensin-converting enzyme 2, a receptor of SARS-CoV2 in the lung, heart, kidney, testis, liver, lymphocytes, and nervous system was confirmed, there are controversial findings to about the observation of SARS-CoV2 RNA in these organs. Moreover, the organ failure may be induced by the cytokine storm, a result of increased levels of inflammatory mediators, endothelial dysfunction, coagulation abnormalities, and infiltration of inflammatory cells into the organs. Therefore, further investigations are needed to detect the exact mechanisms of pathogenesis. Since the involvement of several organs in COVID-19 patients is important for clinicians, increasing their knowledge may help to improve the outcomes and decrease the rate of mortality and morbidity.