scholarly journals SARS-CoV-2: is there neuroinvasion?

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Conor McQuaid ◽  
Molly Brady ◽  
Rashid Deane

Abstract Background SARS-CoV-2, a coronavirus (CoV), is known to cause acute respiratory distress syndrome, and a number of non-respiratory complications, particularly in older male patients with prior health conditions, such as obesity, diabetes and hypertension. These prior health conditions are associated with vascular dysfunction, and the CoV disease 2019 (COVID-19) complications include multiorgan failure and neurological problems. While the main route of entry into the body is inhalation, this virus has been found in many tissues, including the choroid plexus and meningeal vessels, and in neurons and CSF. Main body We reviewed SARS-CoV-2/COVID-19, ACE2 distribution and beneficial effects, the CNS vascular barriers, possible mechanisms by which the virus enters the brain, outlined prior health conditions (obesity, hypertension and diabetes), neurological COVID-19 manifestation and the aging cerebrovascualture. The overall aim is to provide the general reader with a breadth of information on this type of virus and the wide distribution of its main receptor so as to better understand the significance of neurological complications, uniqueness of the brain, and the pre-existing medical conditions that affect brain. The main issue is that there is no sound evidence for large flux of SARS-CoV-2 into brain, at present, compared to its invasion of the inhalation pathways. Conclusions While SARS-CoV-2 is detected in brains from severely infected patients, it is unclear on how it gets there. There is no sound evidence of SARS-CoV-2 flux into brain to significantly contribute to the overall outcomes once the respiratory system is invaded by the virus. The consensus, based on the normal route of infection and presence of SARS-CoV-2 in severely infected patients, is that the olfactory mucosa is a possible route into brain. Studies are needed to demonstrate flux of SARS-CoV-2 into brain, and its replication in the parenchyma to demonstrate neuroinvasion. It is possible that the neurological manifestations of COVID-19 are a consequence of mainly cardio-respiratory distress and multiorgan failure. Understanding potential SARS-CoV-2 neuroinvasion pathways could help to better define the non-respiratory neurological manifestation of COVID-19.

2021 ◽  
Vol 15 ◽  
Author(s):  
Mahmoud Salami

The human gastrointestinal tract hosts trillions of microorganisms that is called “gut microbiota.” The gut microbiota is involved in a wide variety of physiological features and functions of the body. Thus, it is not surprising that any damage to the gut microbiota is associated with disorders in different body systems. Probiotics, defined as living microorganisms with health benefits for the host, can support or restore the composition of the gut microbiota. Numerous investigations have proved a relationship between the gut microbiota with normal brain function as well as many brain diseases, in which cognitive dysfunction is a common clinical problem. On the other hand, increasing evidence suggests that the existence of a healthy gut microbiota is crucial for normal cognitive processing. In this regard, interplay of the gut microbiota and cognition has been under focus of recent researches. In the present paper, I review findings of the studies considering beneficial effects of either gut microbiota or probiotic bacteria on the brain cognitive function in the healthy and disease statuses.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Evelyn Medawar ◽  
Sebastian Huhn ◽  
Arno Villringer ◽  
A. Veronica Witte

Abstract Western societies notice an increasing interest in plant-based eating patterns such as vegetarian and vegan, yet potential effects on the body and brain are a matter of debate. Therefore, we systematically reviewed existing human interventional studies on putative effects of a plant-based diet on the metabolism and cognition, and what is known about the underlying mechanisms. Using the search terms “plant-based OR vegan OR vegetarian AND diet AND intervention” in PubMed filtered for clinical trials in humans retrieved 205 studies out of which 27, plus an additional search extending the selection to another five studies, were eligible for inclusion based on three independent ratings. We found robust evidence for short- to moderate-term beneficial effects of plant-based diets versus conventional diets (duration ≤ 24 months) on weight status, energy metabolism and systemic inflammation in healthy participants, obese and type-2 diabetes patients. Initial experimental studies proposed novel microbiome-related pathways, by which plant-based diets modulate the gut microbiome towards a favorable diversity of bacteria species, yet a functional “bottom up” signaling of plant-based diet-induced microbial changes remains highly speculative. In addition, little is known, based on interventional studies about cognitive effects linked to plant-based diets. Thus, a causal impact of plant-based diets on cognitive functions, mental and neurological health and respective underlying mechanisms has yet to be demonstrated. In sum, the increasing interest for plant-based diets raises the opportunity for developing novel preventive and therapeutic strategies against obesity, eating disorders and related comorbidities. Still, putative effects of plant-based diets on brain health and cognitive functions as well as the underlying mechanisms remain largely unexplored and new studies need to address these questions.


Author(s):  
Venkata Bharat Kumar Pinnelli ◽  
Mangala N. Sirsikar ◽  
W. Vishnu Vandana ◽  
Shrabani Mohanty ◽  
Wilma Delphine Silvia CR ◽  
...  

Background: A new coronavirus (SARS-CoV-2) that emerged from Wuhan, Hubei Province, China, has spread throughout the world and is declared a pandemic by the World Health Organization (WHO). A lot remains to be understood of SARS-CoV-2 and the disease (COVID-19). SARS-CoV-2 has until recently been identified as responsible for both asymptomatic and serious life-threatening infections. The unavailability of specific therapeutic agents is a major hurdle in the treatment and management of COVID-19 patients. The present review attempts to evaluate the immunobiochemical aspects of the pathogenesis, diagnosis, and management of SARS-CoV-2 infection. Main Body: This review is a comprehensive evaluation of the data collected through various sources, including Google Scholar, PubMed, and Scopus. The articles were searched and selected using key words such as “Coronavirus disease (COVID-19)”, “Diagnosis of COVID-19”, Pathogenesis of Covid-19”, “management of COVID-19”, “Immunology of COVID-19”, and “Complications of COVID-19”. The study noted that the novel Coronavirus infection could result in an exaggerated immune response, causing a cytokine storm and damaging several organs of the body. The infected patients develop several complications, including immunological, hematological, and biochemical alterations. Consequently, COVID-19 patients may develop cardiovascular, liver, renal, and neurological complications, among others. Conclusion: An increased understanding of the immunobiochemical aspects of the disease may contribute to better management of SARS-CoV-2-infected persons, as evidenced from the available literature. A holistic approach to the management of COVID-19 patients taking into consideration the effect of COVID-19 infection on various organs of the body assumes increased significance in patient management.


2005 ◽  
Vol 288 (6) ◽  
pp. H2843-H2850 ◽  
Author(s):  
Helena Parfenova ◽  
Pierluigi Carratu ◽  
Dilyara Tcheranova ◽  
Alex Fedinec ◽  
Massroor Pourcyrous ◽  
...  

The extended postictal state is characterized by neurological problems in patients. Inadequate blood supply to the brain and impaired cerebral autoregulation may contribute to seizure-induced neuronal damage. Recent evidence in newborn pigs indicates that activation of the antioxidative enzyme heme oxygenase (HO) at the onset of seizures is necessary for increased cerebral blood flow during the ictal episode and for normal cerebral vascular functioning during the immediate postictal period. We hypothesized that seizures cause prolonged postictal cerebral vascular dysfunction that can be accentuated by HO inhibition and rescued by HO overexpression. Cerebral vascular responses to endothelium-dependent (hypercapnia, bradykinin) and -independent (isoproterenol, sodium nitroprusside) stimuli were assessed 48 h after bicuculline-induced seizures in: 1) saline-control newborn piglets, 2) HO-inhibited animals (HO was inhibited by tin protoporphyrin, SnPP, 3 mg/kg iv), and 3) HO-overexpressing piglets (HO-1 was upregulated by cobalt protoporphyrin, CoPP, 50 mg/kg ip). Extended alterations of HO expression in cerebral microvessels were confirmed by measuring CO production and inducible HO (HO-1) and constitutive HO (HO-2) proteins. Our data provide evidence that seizures cause a severe, sustained, postictal cerebral vascular dysfunction as reflected by impaired vascular reactivity to physiologically relevant dilators. During the delayed postictal state, vascular reactivity to all dilator stimuli was reduced in saline control and, to a greater extent, in HO-inhibited animals. In CoPP-treated piglets, no reduction in postictal cerebral vascular reactivity was observed. These findings may indicate that CoPP prevents postictal cerebral vascular dysfunction by upregulating HO-1, a finding that might have implications for preventing postictal neurological complications.


2021 ◽  
Author(s):  
Alexander Popov ◽  
Nadezda Brazhe ◽  
Anna Fedotova ◽  
Alisa Tiaglik ◽  
Maxim Bychkov ◽  
...  

A high-fat diet (HFD) is generally considered to negatively influence the body, the brain, and cognitive abilities. On the other hand, fat and fatty acids are essential for nourishing and constructing brain tissue. Astrocytes are central for lipolysis and fatty acids metabolism. Here we show that exposure of young mice to one month of HFD elevates lipid content and increases the relative amount of reduced cytochromes in astrocytes but not in neurons. Metabolic changes were paralleled with an enlargement of astrocytic territorial domains due to an increased outgrowth of branches and leaflets. Astrocyte remodeling was associated with an increase in expression of ezrin and with no changes in glial fibrillary acidic protein (GFAP), glutamate transporter-1 (GLT-1), and glutamine synthetase (GS). Such physiological (non-reactive) enlargement of astrocytes in the brain active milieu promoted glutamate clearance and long-term potentiation. These changes translated into improved exploratory behavior. Thus, dietary fat intake is not invariably harmful and might exert beneficial effects depending on the biological context.


Author(s):  
M.P. Sutunkova ◽  
B.A. Katsnelson ◽  
L.I. Privalova ◽  
S.N. Solovjeva ◽  
V.B. Gurvich ◽  
...  

We conducted a comparative assessment of the nickel oxide nanoparticles toxicity (NiO) of two sizes (11 and 25 nm) according to a number of indicators of the body state after repeated intraperitoneal injections of these particles suspensions. At equal mass doses, NiO nanoparticles have been found to cause various manifestations of systemic subchronic toxicity with a particularly pronounced effect on liver, kidney function, the body’s antioxidant system, lipid metabolism, white and red blood, redox metabolism, spleen damage, and some disorders of nervous activity allegedly related to the possibility of nickel penetration into the brain from the blood. The relationship between the diameter and toxicity of particles is ambiguous, which may be due to differences in toxicokinetics, which is controlled by both physiological mechanisms and direct penetration of nanoparticles through biological barriers and, finally, unequal solubility.


2019 ◽  
Vol 25 (23) ◽  
pp. 2555-2568 ◽  
Author(s):  
Rajeev Taliyan ◽  
Sarathlal K. Chandran ◽  
Violina Kakoty

Neurodegenerative disorders are the most devastating disorder of the nervous system. The pathological basis of neurodegeneration is linked with dysfunctional protein trafficking, mitochondrial stress, environmental factors and aging. With the identification of insulin and insulin receptors in some parts of the brain, it has become evident that certain metabolic conditions associated with insulin dysfunction like Type 2 diabetes mellitus (T2DM), dyslipidemia, obesity etc., are also known to contribute to neurodegeneration mainly Alzheimer’s Disease (AD). Recently, a member of the fibroblast growth factor (FGF) superfamily, FGF21 has proved tremendous efficacy in diseases like diabetes mellitus, obesity and insulin resistance (IR). Increased levels of FGF21 have been reported to exert multiple beneficial effects in metabolic syndrome. FGF21 receptors are present in certain areas of the brain involved in learning and memory. However, despite extensive research, its function as a neuroprotectant in AD remains elusive. FGF21 is a circulating endocrine hormone which is mainly secreted by the liver primarily in fasting conditions. FGF21 exerts its effects after binding to FGFR1 and co-receptor, β-klotho (KLB). It is involved in regulating energy via glucose and lipid metabolism. It is believed that aberrant FGF21 signalling might account for various anomalies like neurodegeneration, cancer, metabolic dysfunction etc. Hence, this review will majorly focus on FGF21 role as a neuroprotectant and potential metabolic regulator. Moreover, we will also review its potential as an emerging candidate for combating metabolic stress induced neurodegenerative abnormalities.


2019 ◽  
Vol 19 (3) ◽  
pp. 316-325
Author(s):  
Mahdi Goudarzvand ◽  
Yaser Panahi ◽  
Reza Yazdani ◽  
Hosein Miladi ◽  
Saeed Tahmasebi ◽  
...  

Objective: Experimental autoimmune encephalomyelitis (EAE) is a widely used model for multiple sclerosis. The present study has been designed to compare the efficiencies of oral and intraperitoneal (IP) administration of D-aspartate (D-Asp) on the onset and severity of EAE, the production of neurosteroids, and the expression of neurosteroid receptors and inflammatory mediators in the brain of EAE mice. Methods: In this study, EAE was induced in C57BL/6 mice treated with D-Asp orally (D-Asp-Oral) or by IP injection (D-Asp-IP). On the 20th day, brains (cerebrums) and cerebellums of mice were evaluated by histological analyses. The brains of mice were analyzed for: 1) Neurosteroid (Progesterone, Testosterone, 17β-estradiol) concentrations; 2) gene expressions of cytokines and neurosteroid receptors by reverse transcription polymerase chain reaction, and 3) quantitative determination of D-Asp using liquid chromatography-tandem mass spectrometry. Further, some inflammatory cytokines and matrix metalloproteinase-2 (MMP-2) were identified in the mouse serum using enzyme-linked immunosorbent assay kits. Results: Our findings demonstrated that after D-Asp was administered, it was taken up and accumulated within the brain. Further, IP injection of D-Asp had more beneficial effects on EAE severity than oral gavage. The concentration of the testosterone and 17β-estradiol in D-Asp-IP group was significantly higher than that of the control group. There were no significant differences in the gene expression of cytokine and neurosteroid receptors between control, D-Asp-IP, and D-Asp-Oral groups. However, IP treatment with D-Asp significantly reduced C-C motif chemokine ligand 2 and MMP-2 serum levels compared to control mice. Conclusion: IP injection of D-Asp had more beneficial effects on EAE severity, neurosteroid induction and reduction of inflammatory mediators than oral gavage.


2020 ◽  
Vol 10 (4) ◽  
pp. 355-363
Author(s):  
Mohaddese Mahboubi ◽  
Leila Mohammad Taghizadeh Kashani

Background: In Iranian Traditional Medicine, Boswellia serrata oleo-gum resins were used for the treatment of "Nisyan". "Nisyan" was equivalent to a reduction of memory or forgetfulness. Objective: This review evaluates the traditional believes of B. serrata and memory and its effectiveness on memory loss. Methods: We extracted all traditional and modern information on B. serrata oleo-gum resin preparations and memory from scientific accessible resources (Google Scholar, PubMed, Springer, Science direct, Wiley), non-accessible resources and traditional books. Results: In traditional manuscripts, "Nisyan" is equal to memory loss in modern medicine and was believed to happen as the result of pouring the waste materials into the brain. Traditional practitioners treated "Nisyan" by inhibition of waste production in the brain or cleaning the brain from waste materials. They recommended using the plants with warming effects on the brain. It was believed that B. serrata had beneficial effects on memory functions and its memory enhancing effects have been the subject of pharmacological and clinical trial studies. Conclusion: Despite some documents on the effectiveness of B. serrata oleo-gum-resin on memory functions, there is gap between these investigations, especially in pregnant and nursing mothers. More investigations with large clinical trials are required to complete flaw in order to improve the therapeutic applications of B. serrata on memory functions.


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