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1.
Curr Med Chem ; 2022 Oct 03.
Article in English | MEDLINE | ID: covidwho-20241405

ABSTRACT

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by marked cognitive decline, memory loss, and spatio-temporal troubles and, in severe cases, lack of recognition of family members. Neurological symptoms, cognitive disturbances, and the inflammatory frame due to COVID-19, together with long-term effects, have fueled renewed interest in AD based on similar damage. COVID-19 also caused the acceleration of AD symptom onset. In this regard, the morbidity and mortality of COVID-19 were reported to be increased in patients with AD due to multiple pathological changes such as excessive expression of the viral receptor angiotensin-converting enzyme 2 (ACE2), comorbidities such as diabetes, hypertension, or drug-drug interactions in patients receiving polypharmacy and the high presence of proinflammatory molecules. Furthermore, the release of cytokines, neuroinflammation, oxidative stress, and ferroptosis in both diseases showed common underlying mechanisms, which together worsen the clinical picture and prognosis of these patients.

2.
Free Neuropathol ; 22021 Jan.
Article in English | MEDLINE | ID: covidwho-20241232

ABSTRACT

Despite the interruptions and restrictions to the progress of science that the COVID-19 pandemic has introduced, 2020 was marked by a number of important advances in the field of neurotrauma. Here, I will highlight what I believe are among the most important contributions. This year there were notable advances towards providing clinically useful information on neurotrauma outcome through the use of fluid biomarkers. I also introduce fascinating approaches to studying the role of microglia in nervous system repair and neuroinflammatory mechanisms leading to dysfunction through the use of colony-stimulating factor 1 receptor inhibitors, especially Plexxikon 5622 (PLX5622). Oral administration of this compound is able to deplete microglial elements and then, following withdrawal from the drug, a new population of microglia then repopulates the brain. Use of this approach in traumatic brain injury experimental models has produced important insights into the pathogenetic role of microglia in responding to this process. Important new data on the nature and distribution of tau involvement of neurons and astrocytes in cases of chronic traumatic encephalopathy (CTE) also appeared suggesting differences and similarities to Alzheimer s disease. Additionally, the use of tau-specific PET scan ligands in at-risk populations has suggested that this approach may be able to identify cases with CTE. Lastly, we note the death in the past year of a major contributor to the field of neurotrauma neuropathology, Professor J. Hume Adams.

3.
Acta Neurol Belg ; 123(4): 1247-1256, 2023 Aug.
Article in English | MEDLINE | ID: covidwho-20240624

ABSTRACT

Since the hippocampus is predominantly susceptible to injuries caused by COVID-19, there are increasing data indicating the likelihood of post-infection memory loss and quickening neurodegenerative disorders, such as Alzheimer's disease. This is due to the fact that the hippocampus has imperative functions in spatial and episodic memory as well as learning. COVID-19 activates microglia in the hippocampus and induces a CNS cytokine storm, leading to loss of hippocampal neurogenesis. The functional and structural changes in the hippocampus of COVID-19 patients can explain neuronal degeneration and reduced neurogenesis in the human hippocampus. This will open a window to explain memory and cognitive dysfunctions in "long COVID" through the resultant loss of hippocampal neurogenesis.


Subject(s)
Alzheimer Disease , COVID-19 , Humans , Hippocampus , Learning , Memory Disorders
4.
Eur J Clin Pharmacol ; 79(7): 975-987, 2023 Jul.
Article in English | MEDLINE | ID: covidwho-20239229

ABSTRACT

PURPOSE: Autoimmune encephalitis is a neurological emergency of new-onset altered mental status, caused by an exaggerated immune-mediated response that targets the central nervous system. Autoimmune encephalitis has become an emerging differential diagnosis, when a classical infection cannot explain neurological symptoms. Displaying overlapping clinical presentations, ranging from the insidious onset of cognitive deficiency to more severe forms of encephalopathy with refractory seizures, autoimmune encephalitis can be challenging for clinicians. When evidence of malignancy is absent and pathogenic autoantibodies are undetected, with typical clinical and imaging features of autoimmune encephalitis, seronegative autoimmune encephalitis may be considered. Recently, vaccination-related autoimmune encephalitis and acute encephalitis after COVID-19 vaccination have attracted attention. METHODS AND RESULTS: We report a case series consisting of three patients with autoimmune encephalitis occurring shortly after COVID-19 vaccination and a current review of all previous reported autoimmune encephalitis related to COVID-19 vaccines. CONCLUSION: We emphasise on the prompt diagnosis of autoimmune encephalitis induced by Covid-19 vaccines and its timely treatment to improve the clinical outcome of this severe neurological condition. Post-licencing vaccine safety surveillance for potential adverse events is essential for vaccine safety and public confidence.


Subject(s)
Autoimmune Diseases of the Nervous System , COVID-19 , Encephalitis , Humans , COVID-19 Vaccines/adverse effects , COVID-19/prevention & control , Encephalitis/diagnosis , Encephalitis/etiology , COVID-19 Testing
5.
Viruses ; 15(5)2023 05 05.
Article in English | MEDLINE | ID: covidwho-20235103

ABSTRACT

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.


Subject(s)
COVID-19 , HIV Infections , HIV Seropositivity , HIV-1 , Nervous System Diseases , Humans , COVID-19/complications , SARS-CoV-2 , Nervous System Diseases/epidemiology , Nervous System Diseases/etiology , Central Nervous System , HIV Infections/complications , HIV Infections/drug therapy , HIV Infections/epidemiology
7.
Front Neurol ; 14: 1148327, 2023.
Article in English | MEDLINE | ID: covidwho-20233229

ABSTRACT

Research interest in understanding tinnitus has increased severalfold in the last decade to find a cure for this auditory disorder. Hyperacusis can also accompany tinnitus, although the mechanisms involved in hyperacusis and tinnitus are different. Millions of people suffer from some degree of tinnitus with hearing loss. Tinnitus is believed to be a form of sensory epilepsy, spawning neuronal hyperactivity from the cochlear nucleus and inferior colliculus of the auditory brainstem region. Cannabis has been used for recreation, medicinal purposes, and served as an entheogen from time immemorial. With the current and increasing global medical and recreational cannabis legalization, there is renewed enthusiasm for the use of cannabinoid drugs, and the role of the endocannabinoid system (ECS) in several health disorders including tinnitus which is associated with COVID-19. The ECS signaling pathways have been proposed to affect the underlying pathophysiology of tinnitus. Cannabinoid receptors (CBRs) have been found in the auditory system, raising interest in ECS signaling in hearing and tinnitus. However, previous studies mostly in animal models of tinnitus did not investigate the involvement of CB2Rs but focused on CB1R-based responses, which suggested that CB1R ligands had no effect and may even be harmful and worsen tinnitus. With new molecular techniques and transgenic approaches used to dissect the complexity of the ECS, the role of ECS/CB2R neuroimmunological function in the auditory system and tinnitus is emerging. This perspective proposes the role of emerging neuroimmune crosstalk of the ECS in sound-sensing structures of the auditory system as a potential pharmacogenomic therapeutic target using cannabinoid CB2R ligands in tinnitus in the era of the COVID-19 pandemic.

8.
Pharmaceutics ; 15(5)2023 May 22.
Article in English | MEDLINE | ID: covidwho-20231913

ABSTRACT

Coronavirus infections are neuroinvasive and can provoke injury to the central nervous system (CNS) and long-term illness consequences. They may be associated with inflammatory processes due to cellular oxidative stress and an imbalanced antioxidant system. The ability of phytochemicals with antioxidant and anti-inflammatory activities, such as Ginkgo biloba, to alleviate neurological complications and brain tissue damage has attracted strong ongoing interest in the neurotherapeutic management of long COVID. Ginkgo biloba leaf extract (EGb) contains several bioactive ingredients, e.g., bilobalide, quercetin, ginkgolides A-C, kaempferol, isorhamnetin, and luteolin. They have various pharmacological and medicinal effects, including memory and cognitive improvement. Ginkgo biloba, through its anti-apoptotic, antioxidant, and anti-inflammatory activities, impacts cognitive function and other illness conditions like those in long COVID. While preclinical research on the antioxidant therapies for neuroprotection has shown promising results, clinical translation remains slow due to several challenges (e.g., low drug bioavailability, limited half-life, instability, restricted delivery to target tissues, and poor antioxidant capacity). This review emphasizes the advantages of nanotherapies using nanoparticle drug delivery approaches to overcome these challenges. Various experimental techniques shed light on the molecular mechanisms underlying the oxidative stress response in the nervous system and help comprehend the pathophysiology of the neurological sequelae of SARS-CoV-2 infection. To develop novel therapeutic agents and drug delivery systems, several methods for mimicking oxidative stress conditions have been used (e.g., lipid peroxidation products, mitochondrial respiratory chain inhibitors, and models of ischemic brain damage). We hypothesize the beneficial effects of EGb in the neurotherapeutic management of long-term COVID-19 symptoms, evaluated using either in vitro cellular or in vivo animal models of oxidative stress.

9.
Lekarsky Obzor ; 72(1):4-13, 2023.
Article in English, Slovak | Scopus | ID: covidwho-2323806

ABSTRACT

Advanced glycation end products (AGEs) and their mRAGE receptor play an important role in the pathogenesis of metabolic diseases. AGEs modify proteins and interact with RAGE with subsequent activation of various signaling pathways, including induction of oxidative stress and resulting activation of nuclear factor NFk-B with subsequent inflammatory response. AGE-RAGE axis, along with other mechanisms, is involved in the pathogenesis of later diabetic complications. The role of RAGE in various clinical situations is currently being intensively studied. AGEs and RAGE alone do not appear to serve as a universal biomarker. On the other hand, the soluble AGEs receptor (sRAGE) neutralizes unwanted interactions by competitive binding with AGEs and may be a potential protective factor in the development of some diseases. Low levels of sRAGE have been suggested as a biomarker of diseases other than diabetes mellitus and kidney disease (where sRAGE levels are elevated). Circulating sRAGE levels can be increased or even decreased in various diseases while increasing AGE levels. sRAGE can serve as a biomarker of disease incidence and adverse symptoms or as a prognostic biomarker of irreversible homeostasis or mortality. It seems practical to evaluate the so-called AGE-RAGE stress as the ratio of measured circulating AGEs/sRAGE levels. An increased AGEs/sRAGE ratio may be a universal or risk biomarker. Based on promising experimental results, mRAGE alone may be a therapeutic target in some diseases (Fig. 2, Ref. 107). Text in PDF www.lekarsky.herba.sk. © 2023, Lekarsky Obzor. All Rights Reserved.

10.
Neural Regeneration Research ; 18(1):38-46, 2023.
Article in English | EMBASE | ID: covidwho-2313974

ABSTRACT

Obesity is associated with several diseases, including mental health. Adipose tissue is distributed around the internal organs, acting in the regulation of metabolism by storing and releasing fatty acids and adipokine in the tissues. Excessive nutritional intake results in hypertrophy and proliferation of adipocytes, leading to local hypoxia in adipose tissue and changes in these adipokine releases. This leads to the recruitment of immune cells to adipose tissue and the release of pro-inflammatory cytokines. The presence of high levels of free fatty acids and inflammatory molecules interfere with intracellular insulin signaling, which can generate a neuroinflammatory process. In this review, we provide an up-to-date discussion of how excessive obesity can lead to possible cognitive dysfunction. We also address the idea that obesity-associated systemic inflammation leads to neuroinflammation in the brain, particularly the hypothalamus and hippocampus, and that this is partially responsible for these negative cognitive outcomes. In addition, we discuss some clinical models and animal studies for obesity and clarify the mechanism of action of anti-obesity drugs in the central nervous system.Copyright © 2023 Wolters Kluwer Medknow Publications. All rights reserved.

11.
Appl Biochem Biotechnol ; 2023 May 02.
Article in English | MEDLINE | ID: covidwho-2317278

ABSTRACT

COVID-19 has become a global challenge as there are very few treatment options available. This has proved to impact several physiological implications like immunological injury, myocardial infarction, micro-thrombus formation, neurological complications and multi-organ dysfunction. A combination therapy or a systems pharmacology approach can be adopted to fight against COVID-19. Here, we have proposed withaferin A as a system pharmacophore employing molecular docking strategy using AutoDock Vina and utilising different bioinformatics tools like PharmMapper, STRING database and PANTHER Pathway enrichment analysis. Docking results show that withaferin A exhibits a significant binding affinity with P2Y12 receptor, vitamin D-binding protein and annexin A5, hence implying that it could play a role in anti-thrombosis. Protein-protein interaction network showed its importance in innate immune system. Results also show that this molecule may have significant potential to modulate T cell activation too. Text mining results showed association of STAT3 with withaferin A. Our studies propose that withaferin A might also conquer the cytokine storm via STAT3. This study concludes that two strong targets of withaferin A, i.e. vitamin D-binding protein and STAT3, have been identified and that withaferin A can be used as a system pharmacophore for drug development in order to combat COVID-associated complicacies.

12.
Metab Brain Dis ; 38(3): 795-804, 2023 03.
Article in English | MEDLINE | ID: covidwho-2315296

ABSTRACT

Schizophrenia (SZ) is a devastating neurodevelopmental disease with an accelerated ageing feature. The criteria of metabolic disease firmly fit with those of schizophrenia. Disturbances in energy and mitochondria are at the core of complex pathology. Genetic and environmental interaction creates changes in redox, inflammation, and apoptosis. All the factors behind schizophrenia interact in a cycle where it is difficult to discriminate between the cause and the effect. New technology and advances in the multi-dispensary fields could break this cycle in the future.


Subject(s)
Metabolic Diseases , Schizophrenia , Humans , Schizophrenia/genetics , Schizophrenia/metabolism , Oxidation-Reduction , Aging , Mitochondria/metabolism , Metabolic Diseases/genetics , Metabolic Diseases/metabolism
13.
J Neurosci Res ; 101(6): 952-975, 2023 06.
Article in English | MEDLINE | ID: covidwho-2315263

ABSTRACT

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra. The hallmarks are the presence of Lewy bodies composed mainly of aggregated α-synuclein and immune activation and inflammation in the brain. The neurotropism of SARS-CoV-2 with induction of cytokine storm and neuroinflammation can contribute to the development of PD. Interestingly, overexpression of α-synuclein in PD patients may limit SARS-CoV-2 neuroinvasion and degeneration of dopaminergic neurons; however, on the other hand, this virus can speed up the α-synuclein aggregation. The review aims to discuss the potential link between COVID-19 and the risk of PD, highlighting the need for further studies to authenticate the potential association. We have also overviewed the influence of SARS-CoV-2 infection on the PD course and management. In this context, we presented the prospects for controlling the COVID-19 pandemic and related PD cases that, beyond global vaccination and novel anti-SARS-CoV-2 agents, may include the development of graphene-based nanoscale platforms offering antiviral and anti-amyloid strategies against PD.


Subject(s)
COVID-19 , Parkinson Disease , Humans , alpha-Synuclein/pharmacology , Pandemics , SARS-CoV-2 , Dopaminergic Neurons
14.
Bulletin of Russian State Medical University ; - (6):119-125, 2022.
Article in English | Web of Science | ID: covidwho-2309297

ABSTRACT

Cytology It has been proven that mRNA vaccines are highly effective against the COVID-19 outbreak, and low prevalence of side effects has been shown. However, there are still many gaps in our understanding of the biology and biosafety of nucleic acids as components of lipid nanoparticles (LNPs) most often used as a system for inctracellular delivery of mRNA-based vaccines. It is known that LNPs cause severe injection site inflammation, have broad biodistribution profiles, and are found in multiple tissues of the body, including the brain, after administration. The role of new medications with such pharmacokinetics in inflammation developing in inaccessible organs is poorly understood. The study was aimed to assess the effects of various doses of mRNA-LNP expressing the reporter protein (0, 5, 10, and 20 mu g of mRNA encoding the firefly luciferase) on the expression of neuroinflammation markers (Tnf alpha, Il1 beta, Gfap, Aif1) in the prefrontal cortex and hypothalamus of laboratory animals 4, 8, and 30 h after the intramuscular injection of LNP nanoemulsion. It was shown that mRNA-LNP vaccines in a dose of 10-20 mu g of mRNA could enhance Aif1 expression in the hypothalamus 8 h after vaccination, however, no such differences were observed after 30 h. It was found that the Gfap, l11 beta, Tnf alpha expression levels in the hypothalamus observed at different times in the experimental groups were different. According to the results, mRNA-LNPs administered by the parenteral route can stimulate temporary activation of microglia in certain time intervals in the dose-dependent and site specific manner.

15.
Pharmaceutics ; 15(1)2022 Dec 28.
Article in English | MEDLINE | ID: covidwho-2307760

ABSTRACT

Dexamethasone (DXM) and methylprednisolone (MEP) are potent glucocorticoids used to control several inflammatory conditions. Evidence of delayed DXM reaching the central nervous system (CNS) as well as tachyphylaxis and systemic, undesirable side effects are the main limitations of peripheral delivery. Intranasal administration offers direct access to the brain as it bypasses the blood-brain barrier. The Mucosal Atomization Device is an optimal tool that can achieve rapid absorption into the CNS and the bloodstream across mucosal membranes. This study was designed to evaluate and compare the bioavailability of DXM and MEP after intranasal versus intravenous administration. Two open-label, balanced, randomized, two-treatment, two-period, two-sequence, single-dose, crossover studies were conducted, which involved healthy male and female adult volunteers. After intranasal administration, DXM and MEP were detected in plasma after the first sampling time. Mean peak concentrations of DXM and MEP were 86.61 ng/mL at 60 min and 843.2 ng/mL at 1.5 h post-administration, respectively. DXM and MEP showed high absolute bioavailability, with values of 80% and 95%, respectively. No adverse effects were observed. DXM and MEP systemic bioavailability by intranasal administration was comparable with the intravenous one, suggesting that the intranasal route can be used as a non-invasive and appropriate alternative for systemic drug delivery.

16.
Children (Basel) ; 10(4)2023 Mar 30.
Article in English | MEDLINE | ID: covidwho-2301426

ABSTRACT

COVID-19 impacted the entire world's population, frequently resulting in long-lasting neuropsychiatric complications. Furthermore, social distancing, lockdowns and fear for one's personal health worsen individual psychological wellbeing, especially in children and adolescents. Herein, we discuss the results of studies that specifically reported data about the impact of the COVID-19 pandemic or infection on children with Pediatric Acute-Onset Neuropsychiatric Disorders (PANS). Furthermore, we present the cases of five adolescents with PANS whose symptomatology increased following SARS-CoV-2 infection. What emerged from this study was that COVID-19 resulted in the exacerbation of obsessions, tics, anxiety and mood symptoms and decreased wellbeing. Moreover, new symptoms, as well as new PANS cases, are reported to have arisen after COVID-19 infection. Here, we hypothesize that the pathogenic mechanisms of silent viruses, such as the Epstein-Barr virus, are related to neuroinflammation, immune responses and reactivation, with additional roles played by social-isolation-related inflammatory processes. The discussion of PANS, which represents a model of immune-mediated neuropsychiatric manifestations, is particularly relevant, with the aim of uncovering the mechanisms that lead to neuropsychiatric Post-Acute COVID-19 Syndrome (PACS). Prospects for future studies and treatment implications are discussed.

17.
Adv Exp Med Biol ; 1411: 135-160, 2023.
Article in English | MEDLINE | ID: covidwho-2301272

ABSTRACT

An increasing number of studies have investigated the role of inflammation in psychiatric disorders, by demonstrating how an altered/dysfunctional immunological and inflammatory system may underpin a psychiatric condition. Particularly, several studies specifically investigated the role of a neuroinflammatory biomarker, named C-reactive protein (CRP), in psychiatric disorders. Overall, even though scientific literature so far published still does not appear definitive, CRP is more likely reported to be elevated in several psychiatric disorders, including schizophrenia, mood disorders, anxiety disorders and post-traumatic stress disorder. Moreover, a low-grade inflammation (CRP >3 mg/L) has been more likely observed in a subgroup of patients affected with a more severe psychopathological symptomatology, more treatment resistance and worst clinical mental illness course, strengthening the hypothesis of the need for a different clinical and prognostic characterization based on this concomitant neuroinflammatory predisposition. However, even though further research studies are needed to confirm this preliminary evidence, CRP may represent a potential clinical routine biomarker which could be integrated in the clinical routine practice to better characterize clinical picture and course as well as address clinicians towards a personalized treatment.


Subject(s)
Schizophrenia , Stress Disorders, Post-Traumatic , Humans , Biomarkers/metabolism , C-Reactive Protein/analysis , Inflammation/diagnosis , Schizophrenia/diagnosis , Schizophrenia/drug therapy , Stress Disorders, Post-Traumatic/diagnosis
18.
Health Sci Rep ; 6(4): e1175, 2023 Apr.
Article in English | MEDLINE | ID: covidwho-2300668

ABSTRACT

Background and Aims: Major depressive disorder (MDD) is characterized by the occurrence of one or more depressive episodes lasting a minimum of 2 weeks and is marked by a persistently low mood and a lack of enjoyment in daily activities. The diagnosis of MDD is not possible by a well-established laboratory test or biomarker. A wide range of potential biomarkers for depression have been proposed by many studies, but none of them has adequately described the correlation between the biomarkers and depression. The purpose of this study was to evaluate serum interleukin-1 receptor antagonist (IL-1RA) levels as an early depression risk factor. Methods: The present case-control study included 88 participants. Among them, 44 MDD patients enrolled from the psychiatry department of a public hospital in Dhaka, Bangladesh, and 44 age- and sex-matched healthy controls (HCs) from various sites in Dhaka city. A qualified psychiatrist evaluated the cases and HCs based on the fifth edition of the diagnostic and statistical manual of mental disorders (DSM-5). The Hamilton depression (Ham-D) rating scale was employed to evaluate the intensity of depression. An enzyme-linked immunosorbent assay kit (Boster Bio, USA) was used to determine serum IL-1RA concentrations. Results: We observed no marked alteration in the serum concentration of IL-1RA in MDD patients in comparison to HCs (292.81 ± 24.81 and 288 ± 24.87 pg/mL; p > 0.05). Among MDD patients, we found no noteworthy association between the severity of depression and serum IL-1RA levels. Conclusion: The findings of the present study imply that IL-1RA may not be identified as a promising biomarker for risk assessment of depression. However, its neuroprotective role may be taken into consideration for the understanding of pathophysiology of MDD.

19.
Immun Ageing ; 20(1): 17, 2023 Apr 12.
Article in English | MEDLINE | ID: covidwho-2300515

ABSTRACT

Advanced age is one of the significant risk determinants for coronavirus disease 2019 (COVID-19)-related mortality and for long COVID complications. The contributing factors may include the age-related dynamical remodeling of the immune system, known as immunosenescence and chronic low-grade systemic inflammation. Both of these factors may induce an inflammatory milieu in the aged brain and drive the changes in the microenvironment of neurons and microglia, which are characterized by a general condition of chronic inflammation, so-called neuroinflammation. Emerging evidence reveals that the immune privilege in the aging brain may be compromised. Resident brain cells, such as astrocytes, neurons, oligodendrocytes and microglia, but also infiltrating immune cells, such as monocytes, T cells and macrophages participate in the complex intercellular networks and multiple reciprocal interactions. Especially changes in microglia playing a regulatory role in inflammation, contribute to disturbing of the brain homeostasis and to impairments of the neuroimmune responses. Neuroinflammation may trigger structural damage, diminish regeneration, induce neuronal cell death, modulate synaptic remodeling and in this manner negatively interfere with the brain functions.In this review article, we give insights into neuroimmune interactions in the aged brain and highlight the impact of COVID-19 on the functional systems already modulated by immunosenescence and neuroinflammation. We discuss the potential ways of these interactions with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and review proposed neuroimmune mechanisms and biological factors that may contribute to the development of persisting long COVID conditions. We summarize the potential mechanisms responsible for long COVID, including inflammation, autoimmunity, direct virus-mediated cytotoxicity, hypercoagulation, mitochondrial failure, dysbiosis, and the reactivation of other persisting viruses, such as the Cytomegalovirus (CMV). Finally, we discuss the effects of various interventional options that can decrease the propagation of biological, physiological, and psychosocial stressors that are responsible for neuroimmune activation and which may inhibit the triggering of unbalanced inflammatory responses. We highlight the modulatory effects of bioactive nutritional compounds along with the multimodal benefits of behavioral interventions and moderate exercise, which can be applied as postinfectious interventions in order to improve brain health.

20.
Front Med (Lausanne) ; 10: 1011936, 2023.
Article in English | MEDLINE | ID: covidwho-2299142

ABSTRACT

The Long COVID/Post Acute Sequelae of COVID-19 (PASC) group includes patients with initial mild-to-moderate symptoms during the acute phase of the illness, in whom recovery is prolonged, or new symptoms are developed over months. Here, we propose a description of the pathophysiology of the Long COVID presentation based on inflammatory cytokine cascades and the p38 MAP kinase signaling pathways that regulate cytokine production. In this model, the SARS-CoV-2 viral infection is hypothesized to trigger a dysregulated peripheral immune system activation with subsequent cytokine release. Chronic low-grade inflammation leads to dysregulated brain microglia with an exaggerated release of central cytokines, producing neuroinflammation. Immunothrombosis linked to chronic inflammation with microclot formation leads to decreased tissue perfusion and ischemia. Intermittent fatigue, Post Exertional Malaise (PEM), CNS symptoms with "brain fog," arthralgias, paresthesias, dysautonomia, and GI and ophthalmic problems can consequently arise as result of the elevated peripheral and central cytokines. There are abundant similarities between symptoms in Long COVID and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). DNA polymorphisms and viral-induced epigenetic changes to cytokine gene expression may lead to chronic inflammation in Long COVID patients, predisposing some to develop autoimmunity, which may be the gateway to ME/CFS.

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