Neurological involvement in the respiratory manifestations of COVID-19 patients

Mapping ACE2 and TMPRSS2 co-expression in human brain tissue: implications for SARS-CoV-2 neurological manifestations

The Coronavirus Disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) primarily targets respiratory cells, but emerging evidence shows neurological involvement, with the virus directly affecting neurons and glia. SARS-CoV-2 entry into a target cell requires co-expression of ACE2 (Angiotensin-converting enzyme-2) and TMPRSS2 (Trans membrane serine protease-2). Relevant literature on human neurological tissue is sparse and mostly focused on the olfactory areas. This prompted our study to map brain-wide expression of these entry proteins and assess age-related changes. The normal brain tissue samples were collected from cerebral cortex, hippocampus, basal ganglia, thalamus, hypothalamus, brain stem and cerebellum; and were divided into two groups - up to 40 years (n = 10) and above 40 years (n = 10). ACE2 and TMPRSS2 gene expression analysis was done using qRT-PCR and protein co-expression was seen by immunofluorescence. The ACE2 and TMPRSS2 gene expression was observed to be highest in hypothalamus and thalamus regions, respectively. Immunoreactivity for both ACE-2 and TMPRSS2 was observed in all examined brain regions, confirming the presence of these viral entry receptors. Co-localisation was maximum in hypothalamus. Our study did not find any trend related to different age groups. The expression of both these viral entry receptors suggests that normal human brain is susceptibility to SARS-CoV-2, perhaps which could be related to the cognitive and neurological impairment that occur in patients.

The prevalence and risk of depression in aged COVID-19 survivors: a bibliometric and meta-analysis

To explore depression prevalence and related risk factors among elderly coronavirus disease 2019 (COVID-19) survivors, while also evaluating research characteristics. We searched Web of Science, PubMed, Embase, Scopus, CNKI and Wanfang Data for studies that reported COVID-19 and depression in older adults. 'Bibliometrix' facilitated bibliometric analysis and information visualisation. Random-effects models merged depression prevalence and relevant risks. Publication bias and its impact were examined using funnel plots, Begg's test, Egger's linear regression, and trim-and-fill method. Meta-regression, bubble plots, and Baujat plots probed heterogeneity. Sensitivity analysis applied the leave-one-out method. The study is registered with PROSPERO, CRD42023417706. The bibliometric analysis comprised 138 studies. Publication frequency peaked in the US, China, and Italy, reflecting significant growth. The meta-analysis comprised 43 studies. Elderly COVID-19 patients exhibit 28.33% depression prevalence (95% CI: 21.24-35.97). Severe cases (43.91%, 95% CI: 32.28-55.88) experienced higher depression prevalence than mild cases (16.45%, 95% CI: 11.92-21.50). Sex had no depression prevalence impact based on bubble plots. Notably, depression risk did not significantly differ between elderly and young COVID-19 patients (odds ratio (OR) = 1.1808, 95% CI: 0.7323-1.9038). However, COVID-19 infection emerged as a substantial elderly depression risk factor (OR = 1.8521, 95% CI: 1.2877-2.6639). Sensitivity analysis confirmed result robustness. Elderly COVID-19 survivors are likely to develop depression symptoms with regional variations. Severe cases are associated with heightened depression prevalence. COVID-19 infection stands out as a key elderly depression risk factor, while sex does not influence prevalence. The field's expansion necessitates sustained collaboration and extensive research endeavours.

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.

COVID-19 and Alzheimer's Disease Share Common Neurological and Ophthalmological Manifestations: A Bidirectional Risk in the Post-Pandemic Future

A growing body of evidence indicates that a neuropathological cross-talk takes place between the coronavirus disease 2019 (COVID-19) -the pandemic severe pneumonia that has had a tremendous impact on the global economy and health since three years after its outbreak in December 2019- and Alzheimer's Disease (AD), the leading cause of dementia among human beings, reaching 139 million by the year 2050. Even though COVID-19 is a primary respiratory disease, its causative agent, the so-called Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), is also endowed with high neuro-invasive potential (Neurocovid). The neurological complications of COVID-19, resulting from the direct viral entry into the Central Nervous System (CNS) and/or indirect systemic inflammation and dysregulated activation of immune response, encompass memory decline and anosmia which are typically associated with AD symptomatology. In addition, patients diagnosed with AD are more vulnerable to SARS-CoV-2 infection and are inclined to more severe clinical outcomes. In the present review, we better elucidate the intimate connection between COVID-19 and AD by summarizing the involved risk factors/targets and the underlying biological mechanisms shared by these two disorders with a particular focus on the Angiotensin-Converting Enzyme 2 (ACE2) receptor, APOlipoprotein E (APOE), aging, neuroinflammation and cellular pathways associated with the Amyloid Precursor Protein (APP)/Amyloid beta (Aβ) and tau neuropathologies. Finally, the involvement of ophthalmological manifestations, including vitreo-retinal abnormalities and visual deficits, in both COVID-19 and AD are also discussed. Understanding the common physiopathological aspects linking COVID-19 and AD will pave the way to novel management and diagnostic/therapeutic approaches to cope with them in the post-pandemic future.

Case Report: Four cases of SARS-CoV-2-associated Guillain-Barré Syndrome with SARS-CoV-2-positive cerebrospinal fluid detected by metagenomic next-generation sequencing: a retrospective case series from China

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is often absent or at low levels in the cerebrospinal fluid (CSF) of patients with previous SARS-CoV-2-associated Guillain-Barré syndrome (GBS). This has led to speculation that SARS-CoV-2-associated GBS is more likely mediated by post-infectious immunity or a parainfection. This understanding has influenced the development of treatment regimens for SARS-CoV-2-associated GBS. This paper reports our experience with four Chinese patients with SARS-CoV-2-associated GBS who tested positive for SARS-CoV-2 RNA in the CSF. They developed symptoms of peripheral nerve damage 4-15 days after fever and confirmed SARS-CoV-2 infection, all of whom presented with progressive weakness of both lower limbs; three with autonomic nerve function impairment such as constipation and urination disorder; and one with polycranial neuritis and Miller-Fisher syndrome. Three patients were tested for anti-ganglioside antibodies, and one tested positive for GD1a-IgG. Four patients recovered well after treatment with anti-viral drugs combined with intravenous immunoglobulin. The present results showed that SARS-CoV-2 RNA can be detected via mNGS in the CSF of some patients with SARS-CoV-2-associated GBS, suggesting that SARS-CoV-2-associated GBS may have multiple pathogeneses.

Acute Phrenic Neuropathy and Diaphragmatic Dysfunction as a Complication of COVID-19: A Report of Four Cases

Among the neurological manifestations associated with coronavirus disease 2019 (COVID-19), neuropathies are rare. They have been associated with prolonged prostration and metabolic failure in a seriously ill patient. We present a case series of four Mexican patients diagnosed with diaphragmatic dysfunction due to phrenic neuropathy during acute COVID-19, documented by conduction velocities of the phrenic nerves. Blood tests, chest computed tomography (CT), and nerve conduction velocities of the phrenic nerves were performed. COVID-19 patients with phrenic nerve neuropathy represent a therapeutic challenge since they have high oxygen requirements due to the malfunction of ventilatory mechanics secondary to neuromuscular damage, as well as the damage that pneumonia generates in lung tissue. We confirm and extend the neurological manifestations of COVID-19, the impact on the neuromuscular dysfunction of the diaphragm, and its consequences such as the difficulty of weaning from mechanical ventilation.

Development of New Mental and Physical Health Sequelae among US Veterans after COVID-19

Background:COVID-19 sequelae among veterans need evaluation. Design: Propensity-score-matched retrospective cohort study. Participants: A total 778,738 veterans, who were tested for COVID-19 at VA facilities between 20 February 2020−27 March 2021. Main Outcomes: Development of new physical and mental health conditions (incidence) during the follow-up period of 7 days to 3 months after the diagnosis of COVID-19. Results: Out of 778,738 veterans, 149,205 (19.2%) were inpatients and 629,533 (80.8%) were outpatients. 123,757 (15.9%) diagnosed with COVID-19. Mean age was 61 ± 15.4, mostly men (89%) who were White (68%) and non-Hispanic (88%). In hospitalized patients, COVID-19 is associated with significantly higher incidences of physical conditions (venous thromboembolism (5.8% vs. 2.9%, p < 0.001), pulmonary circulation disorder (5.1% vs. 2.9%, p < 0.001), chronic lung disease (8.4% vs. 4.3%, p < 0.001), acute kidney injury (16.4% vs. 9.3%, p < 0.001), chronic kidney disease (6.5% vs. 4.8%, p < 0.001), cardiac arrhythmia (15.2% vs. 10.9%, p < 0.001), complicated hypertension (12% vs. 8.5%, p < 0.001), coagulopathy (6.1% vs. 2.6%, p < 0.001), fluid/electrolyte disorders (24.4% vs. 12.6%, p < 0.001) and neurological disorders (7.1% vs. 3.8%, p < 0.001)) and mental health conditions (depressive episode (6.6% vs. 4.3%, p < 0.001), adjustment disorder (2.5% vs. 1.7%, p < 0.001), insomnia (4.9% vs. 3.2%, p < 0.001) and dementia (3.0% vs. 1.9%, p < 0.001)) compared to propensity-matched hospitalized COVID-19 negative patients. In outpatient settings, COVID-19 diagnosis is associated with smaller increase in the incidences of the physical sequelae. Conclusions: In this propensity-score-matched analysis of US veterans, COVID-19 survivors, especially those who were hospitalized, developed new physical and mental health sequelae at a significantly higher rate than those without COVID-19.

COVID-19 and neurological sequelae: Vitamin D as a possible neuroprotective and/or neuroreparative agent

SARS-CoV-2, the etiological agent of the current COVID-19 pandemic, belongs to a broad family of coronaviruses that also affect humans. SARS-CoV-2 infection usually leads to bilateral atypical pneumonia with significant impairment of respiratory function. However, the infectious capacity of SARS-CoV-2 is not limited to the respiratory system, but may also affect other vital organs such as the brain. The central nervous system is vulnerable to cell damage via direct invasion or indirect virus-related effects leading to a neuroinflammatory response, processes possibly associated with a decrease in the activity of angiotensin II converting enzyme (ACE2), the canonical cell-surface receptor for SARS-CoV-2. This enzyme regulates neuroprotective and neuroimmunomodulatory functions and can neutralize both inflammation and oxidative stress generated at the cellular level. Furthermore, there is evidence of an association between vitamin D deficiency and predisposition to the development of severe forms of COVID-19, with its possible neurological and neuropsychiatric sequelae: vitamin D has the ability to down-modulate the effects of neuroinflammatory cytokines, among other anti-inflammatory/immunomodulatory effects, thus attenuating harmful consequences of COVID-19. This review critically analyzes current evidence supporting the notion that vitamin D may act as a neuroprotective and neuroreparative agent against the neurological sequelae of COVID-19.

Neurologic complications of coronavirus and other respiratory viral infections

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

What can cerebrospinal fluid testing and brain autopsies tell us about viral neuroinvasion of SARS-CoV-2

To provide instructive clues for clinical practice and further research of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, we analyzed the existing literature on viral neuroinvasion of SARS-CoV-2 in coronavirus disease 2019 (COVID-19) patients. To date, SARS-CoV-2 has been detected in the cerebrospinal fluid (CSF) or brain parenchyma in quite a few patients, which provide undeniable evidence for the neuroinvasive potential of this novel coronavirus. In contrast with the cerebrum and cerebellum, the detection rate of SARS-CoV-2 was higher in the olfactory system and the brainstem, both of which also showed severe microgliosis and lymphocytic infiltrations. As compared with the number of patients who underwent viral testing in the central nervous system (CNS), the number of patients showing positive results seems very small. However, it seems too early to conclude that the neuroinvasion of SARS-CoV-2 is rare in COVID-19 patients because the detection methods or sampling procedures in some studies may not be suitable or sufficient to reveal the CNS infection induced by neurotropic viruses. Moreover, the primary symptoms and/or causes of death were distinctly different among examined patients, which probably caused more conspicuous pathological changes than those due to the direct infection that usually localized to specific brain areas. Unfortunately, most autopsy studies did not provide sufficient details about neurological symptoms or suspected diagnoses of the examined patients, and the documentation of neuropathological changes was often incomplete. Given the complex pathophysiology of COVID-19 and the characteristics of neurotropic viruses, it is understandable that any study of the CNS infection may inevitably have limitations.