Mitochondria and microbiota dysfunction in COVID-19 pathogenesis

COVID-19, Cation Dysmetabolism, Sialic Acid, CD147, ACE2, Viroporins, Hepcidin and Ferroptosis: A Possible Unifying Hypothesis

Background: iron and calcium dysmetabolism, with hyperferritinemia, hypoferremia, hypocalcemia and anemia have been documented in the majority of COVID-19 patients at later/worse stages. Furthermore, complementary to ACE2, both sialic acid (SA) molecules and CD147 proved relevant host receptors for SARS-CoV-2 entry, which explains the viral attack to multiple types of cells, including erythrocytes, endothelium and neural tissue. Several authors advocated that cell ferroptosis may be the core and final cell degenerative mechanism. Methods: a literature research was performed in several scientific search engines, such as PubMed Central, Cochrane Library, Chemical Abstract Service. More than 500 articles were retrieved until mid-December 2021, to highlight the available evidence about the investigated issues. Results: based on COVID-19 literature data, we have highlighted a few pathophysiological mechanisms, associated with virus-based cation dysmetabolism, multi-organ attack, mitochondria degeneration and ferroptosis. Our suggested elucidated pathological sequence is: a) spike protein subunit S1 docking with sialylated membrane glycoproteins/receptors (ACE2, CD147), and S2 subunit fusion with the lipid layer; b) cell membrane morpho-functional changes due to the consequent electro-chemical variations and viroporin action, which induce an altered ion channel function and intracellular cation accumulation; c) additional intracellular iron concentration due to a deregulated hepcidin-ferroportin axis, with higher hepcidin levels. Viral invasion may also affect erythrocytes/erythroid precursors, endothelial cells and macrophages, through SA and CD147 receptors, with relative hemoglobin and iron/calcium dysmetabolism. AB0 blood group, hemochromatosis, or environmental elements may represent possible factors which affect individual susceptibility to COVID-19.     Conclusions: our literature analysis confirms the combined role of SA molecules, ACE2, CD147, viroporins and hepcidin in determining the cation dysmetabolism and final ferroptosis in the cells infected by SARS-CoV-2. The altered ion channels and electrochemical gradients of the cell membrane have a pivotal role in the virus entry and cell dysmetabolism, with subsequent multi-organ immune-inflammatory degeneration and erythrocyte/hemoglobin alterations.

Effect of Fucoidan on the Mitochondrial Membrane Potential (ΔΨm) of Leukocytes from Patients with Active COVID-19 and Subjects That Recovered from SARS-CoV-2 Infection

Fucoidan is a polysaccharide obtained from marine brown algae, with anti-inflammatory, anti-viral, and immune-enhancing properties, thus, fucoidan may be used as an alternative treatment (complementary to prescribed medical therapy) for COVID-19 recovery. This work aimed to determine the ex-vivo effects of treatment with fucoidan (20 µg/mL) on mitochondrial membrane potential (ΔΨm, using a cationic cyanine dye, 3,3'-dihexyloxacarbocyanine iodide (DiOC6(3)) on human peripheral blood mononuclear cells (HPBMC) isolated from healthy control (HC) subjects, COVID-19 patients (C-19), and subjects that recently recovered from COVID-19 (R1, 40 ± 13 days after infection). In addition, ex-vivo treatment with fucoidan (20 and 50 µg/mL) was evaluated on ΔΨm loss induced by carbonyl cyanide 3-chlorophenylhydrazone (CCCP, 150 µM) in HPBMC isolated from healthy subjects (H) and recovered subjects at 11 months post-COVID-19 (R2, 335 ± 20 days after infection). Data indicate that SARS-CoV-2 infection induces HPBMC loss of ΔΨm, even 11 months after infection, however, fucoidan promotes recovery of ΔΨm in PBMCs from COVID-19 recovered subjects. Therefore, fucoidan may be a potential treatment to diminish long-term sequelae from COVID-19, using mitochondria as a therapeutic target for the recovery of cellular homeostasis.

Peripheral Blood Mitochondrial DNA Levels Were Modulated by SARS-CoV-2 Infection Severity and Its Lessening Was Associated With Mortality Among Hospitalized Patients With COVID-19

Introduction

During severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the virus hijacks the mitochondria causing damage of its membrane and release of mt-DNA into the circulation which can trigger innate immunity and generate an inflammatory state. In this study, we explored the importance of peripheral blood mt-DNA as an early predictor of evolution in patients with COVID-19 and to evaluate the association between the concentration of mt-DNA and the severity of the disease and the patient’s outcome.

Methods

A total 102 patients (51 COVID-19 cases and 51 controls) were included in the study. mt-DNA obtained from peripheral blood was quantified by qRT-PCR using the NADH mitochondrial gene.

Results

There were differences in peripheral blood mt-DNA between patients with COVID-19 (4.25 ng/μl ± 0.30) and controls (3.3 ng/μl ± 0.16) (p = 0.007). Lower mt-DNA concentrations were observed in patients with severe COVID-19 when compared with mild (p= 0.005) and moderate (p= 0.011) cases of COVID-19. In comparison with patients with severe COVID-19 who survived (3.74 ± 0.26 ng/μl) decreased levels of mt-DNA in patients with severe COVID-19 who died (2.4 ± 0.65 ng/μl) were also observed (p = 0.037).

Conclusion

High levels of mt-DNA were associated with COVID-19 and its decrease could be used as a potential biomarker to establish a prognosis of severity and mortality of patients with COVID-19.

Can SARS-CoV-2 Infection Exacerbate Alzheimer's Disease? An Overview of Shared Risk Factors and Pathogenetic Mechanisms

The current coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus (SARS-CoV)-2, is affecting every aspect of global society, including public healthcare systems, medical care access, and the economy. Although the respiratory tract is primarily affected by SARS-CoV-2, emerging evidence suggests that the virus may also reach the central nervous system (CNS), leading to several neurological issues. In particular, people with a diagnosis of Alzheimer's disease (AD) are a vulnerable group at high risk of contracting COVID-19, and develop more severe forms and worse outcomes, including death. Therefore, understanding shared links between COVID-19 and AD could aid the development of therapeutic strategies against both. Herein, we reviewed common risk factors and potential pathogenetic mechanisms that might contribute to the acceleration of neurodegenerative processes in AD patients infected by SARS-CoV-2.

COVID-19 and the Assessment of Coenzyme Q10

Coenzyme Q10 (CoQ10) plays an essential electron carrier role in the mitochondrial electron transfer chain (ETC) as well as being a potent antioxidant and influencing inflammatory mediators. In view of these functions, the reason why certain individuals may be more susceptible to the severe disease or long-term complications (long COVID) of COVID-19 infection may be associated with an underlying deficit in cellular CoQ10 status. Thus, our group has outlined an analytical method for the determination of cellular CoQ10 status using HPLC linked UV detection at 275 nm. This method has been utilized in patient tissue samples to investigate evidence of a CoQ10 deficiency and thus may have potential in determining the possible susceptibility of individuals to severe disease associated with COVID-19 infection or to long COVID.

Reactive Oxygen Species in the Adverse Outcome Pathway Framework: Toward Creation of Harmonized Consensus Key Events

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are formed as a result of natural cellular processes, intracellular signaling, or as adverse responses associated with diseases or exposure to oxidizing chemical and non-chemical stressors. The action of ROS and RNS, collectively referred to as reactive oxygen and nitrogen species (RONS), has recently become highly relevant in a number of adverse outcome pathways (AOPs) that capture, organize, evaluate and portray causal relationships pertinent to adversity or disease progression. RONS can potentially act as a key event (KE) in the cascade of responses leading to an adverse outcome (AO) within such AOPs, but are also known to modulate responses of events along the AOP continuum without being an AOP event itself. A substantial discussion has therefore been undertaken in a series of workshops named "Mystery or ROS" to elucidate the role of RONS in disease and adverse effects associated with exposure to stressors such as nanoparticles, chemical, and ionizing and non-ionizing radiation. This review introduces the background for RONS production, reflects on the direct and indirect effects of RONS, addresses the diversity of terminology used in different fields of research, and provides guidance for developing a harmonized approach for defining a common event terminology within the AOP developer community.

Measurement of Mitochondrial Respiration in Cryopreserved Human Peripheral Blood Mononuclear Cells (PBMCs)

Inflammatory diseases caused by infectious agents such as the SARS-CoV-2 virus can lead to impaired reductive-oxidative (REDOX) balance and disrupted mitochondrial function. Peripheral blood mononuclear cells (PBMCs) provide a useful model for studying the effects of inflammatory diseases on mitochondrial function but can be limited by the need to store these cells by cryopreservation prior to assay. Here, we describe a method for improving and determining PBMC viability with normalization of values to number of living cells. The approach can be applied not only to PBMC samples derived from patients with diseases marked by an altered inflammatory response such as viral infections.

Multiplex Testing of Oxidative-Reductive Pathway in Patients with COVID-19

Infection with SARS-CoV-2, the causative agent of COVID-19, causes numerous cellular dysfunctions. The virus enters the host cells and hijacks the cell machinery for its replication, resulting in disturbances of the oxidative, reductive balance, increased production of damaging reactive oxygen species (ROS), and mitochondrial dysfunction. This damaging cycle can make cells less resistant to infection and make the host more likely to experience a severe disease course. Treatment with antioxidants has been tested as a potential approach to reduce the effects of this disorder. Here, we present a protocol to assess the impact of treatment with a mixture of curcuminoids on physiological and molecular biomarkers, focusing on determining total antioxidant capacity. We used a cohort of diabetes patients with an imbalance in redox mechanisms as such patients are more likely to become severely ill from COVID-19 than healthy persons.

From maternal breath to infant's cells: Impact of maternal respiratory infections on infants 'immune responses

In utero exposure to maternally-derived antigens following chronic infection is associated with modulation of infants 'immune response, differential susceptibility to post-natal infections and immune response toward vaccines. The maternal environment, both internal (microbiota) and external (exposure to environmental microbes) also modulates infant's immune response but also the clinical phenotype after birth. Vertical transmission of ubiquitous respiratory pathogens such as influenza and COVID-19 is uncommon. Evidence suggest that in utero exposure to maternal influenza and SARS-CoV-2 infections may have a significant impact on the developing immune system with activation of both innate and adaptive responses, possibly related to placental inflammation. Here in, we review how maternal respiratory infections, associated with airway, systemic and placental inflammation but also changes in maternal microbiota might impact infant's immune responses after birth. The clinical impact of immune modifications observed following maternal respiratory infections remains unexplored. Given the high frequencies of respiratory infections during pregnancy (COVID-19, influenza but also RSV and HMPV), the impact on global child health could be important.

Retrospective Study of Outcomes and Hospitalization Rates of Patients in Italy with a Confirmed Diagnosis of Early COVID-19 and Treated at Home Within 3 Days or After 3 Days of Symptom Onset with Prescribed and Non-Prescribed Treatments Between November 2020 and August 2021

BACKGROUND This retrospective study aimed to investigate outcomes and hospitalization rates in patients with a confirmed diagnosis of early COVID-19 treated at home with prescribed and non-prescribed treatments. MATERIAL AND METHODS The medical records of a cohort of 158 Italian patients with early COVID-19 treated at home were analyzed. Treatments consisted of indomethacin, low-dose aspirin, omeprazole, and a flavonoid-based food supplement, plus azithromycin, low-molecular-weight heparin, and betamethasone as needed. The association of treatment timeliness and of clinical variables with the duration of symptoms and with the risk of hospitalization was evaluated by logistic regression. RESULTS Patients were divided into 2 groups: group 1 (n=85) was treated at the earliest possible time (<72 h from onset of symptoms), and group 2 (n=73) was treated >72 h after the onset of symptoms. Clinical severity at the beginning of treatment was similar in the 2 groups. In group 1, symptom duration was shorter than in group 2 (median 6.0 days vs 13.0 days, P<0.001) and no hospitalizations occurred, compared with 19.18% hospitalizations in group 2. One patient in group 1 developed chest X-ray alterations and 2 patients experienced an increase in D-dimer levels, compared with 30 and 22 patients, respectively, in group 2. The main factor determining the duration of symptoms and the risk of hospitalization was the delay in starting therapy (P<0.001). CONCLUSIONS This real-world study of patients in the community showed that early diagnosis and early supportive patient management reduced the severity of COVID-19 and reduced the rate of hospitalization.

Differential Co-Expression Network Analysis Reveals Key Hub-High Traffic Genes as Potential Therapeutic Targets for COVID-19 Pandemic

Background

The recent emergence of COVID-19, rapid worldwide spread, and incomplete knowledge of molecular mechanisms underlying SARS-CoV-2 infection have limited development of therapeutic strategies. Our objective was to systematically investigate molecular regulatory mechanisms of COVID-19, using a combination of high throughput RNA-sequencing-based transcriptomics and systems biology approaches.

Methods

RNA-Seq data from peripheral blood mononuclear cells (PBMCs) of healthy persons, mild and severe 17 COVID-19 patients were analyzed to generate a gene expression matrix. Weighted gene co-expression network analysis (WGCNA) was used to identify co-expression modules in healthy samples as a reference set. For differential co-expression network analysis, module preservation and module-trait relationships approaches were used to identify key modules. Then, protein-protein interaction (PPI) networks, based on co-expressed hub genes, were constructed to identify hub genes/TFs with the highest information transfer (hub-high traffic genes) within candidate modules.

Results

Based on differential co-expression network analysis, connectivity patterns and network density, 72% (15 of 21) of modules identified in healthy samples were altered by SARS-CoV-2 infection. Therefore, SARS-CoV-2 caused systemic perturbations in host biological gene networks. In functional enrichment analysis, among 15 non-preserved modules and two significant highly-correlated modules (identified by MTRs), 9 modules were directly related to the host immune response and COVID-19 immunopathogenesis. Intriguingly, systemic investigation of SARS-CoV-2 infection identified signaling pathways and key genes/proteins associated with COVID-19's main hallmarks, e.g., cytokine storm, respiratory distress syndrome (ARDS), acute lung injury (ALI), lymphopenia, coagulation disorders, thrombosis, and pregnancy complications, as well as comorbidities associated with COVID-19, e.g., asthma, diabetic complications, cardiovascular diseases (CVDs), liver disorders and acute kidney injury (AKI). Topological analysis with betweenness centrality (BC) identified 290 hub-high traffic genes, central in both co-expression and PPI networks. We also identified several transcriptional regulatory factors, including NFKB1, HIF1A, AHR, and TP53, with important immunoregulatory roles in SARS-CoV-2 infection. Moreover, several hub-high traffic genes, including IL6, IL1B, IL10, TNF, SOCS1, SOCS3, ICAM1, PTEN, RHOA, GDI2, SUMO1, CASP1, IRAK3, HSPA5, ADRB2, PRF1, GZMB, OASL, CCL5, HSP90AA1, HSPD1, IFNG, MAPK1, RAB5A, and TNFRSF1A had the highest rates of information transfer in 9 candidate modules and central roles in COVID-19 immunopathogenesis.

Conclusion

This study provides comprehensive information on molecular mechanisms of SARS-CoV-2-host interactions and identifies several hub-high traffic genes as promising therapeutic targets for the COVID-19 pandemic.

Of mitochondrion and COVID-19

COVID-19, a pandemic disease caused by a viral infection, is associated with a high mortality rate. Most of the signs and symptoms, e.g. cytokine storm, electrolytes imbalances, thromboembolism, etc., are related to mitochondrial dysfunction. Therefore, targeting mitochondrion will represent a more rational treatment of COVID-19. The current work outlines how COVID-19's signs and symptoms are related to the mitochondrion. Proper understanding of the underlying causes might enhance the opportunity to treat COVID-19.

Common mtDNA variations at C5178a and A249d/T6392C/G10310A decrease the risk of severe COVID-19 in a Han Chinese population from Central China

BACKGROUND

Mitochondria have been shown to play vital roles during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) development. Currently, it is unclear whether mitochondrial DNA (mtDNA) variants, which define mtDNA haplogroups and determine oxidative phosphorylation performance and reactive oxygen species production, are associated with COVID-19 risk.

METHODS

A population-based case-control study was conducted to compare the distribution of mtDNA variations defining mtDNA haplogroups between healthy controls (n = 615) and COVID-19 patients (n = 536). COVID-19 patients were diagnosed based on molecular diagnostics of the viral genome by qPCR and chest X-ray or computed tomography scanning. The exclusion criteria for the healthy controls were any history of disease in the month preceding the study assessment. MtDNA variants defining mtDNA haplogroups were identified by PCR-RFLPs and HVS-I sequencing and determined based on mtDNA phylogenetic analysis using Mitomap Phylogeny. Student's t-test was used for continuous variables, and Pearson's chi-squared test or Fisher's exact test was used for categorical variables. To assess the independent effect of each mtDNA variant defining mtDNA haplogroups, multivariate logistic regression analyses were performed to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) with adjustments for possible confounding factors of age, sex, smoking and diseases (including cardiopulmonary diseases, diabetes, obesity and hypertension) as determined through clinical and radiographic examinations.

RESULTS

Multivariate logistic regression analyses revealed that the most common investigated mtDNA variations (> 10% in the control population) at C5178a (in NADH dehydrogenase subunit 2 gene, ND2) and A249d (in the displacement loop region, D-loop)/T6392C (in cytochrome c oxidase I gene, CO1)/G10310A (in ND3) were associated with a reduced risk of severe COVID-19 (OR = 0.590, 95% CI 0.428-0.814, P = 0.001; and OR = 0.654, 95% CI 0.457-0.936, P = 0.020, respectively), while A4833G (ND2), A4715G (ND2), T3394C (ND1) and G5417A (ND2)/C16257a (D-loop)/C16261T (D-loop) were related to an increased risk of severe COVID-19 (OR = 2.336, 95% CI 1.179-4.608, P = 0.015; OR = 2.033, 95% CI 1.242-3.322, P = 0.005; OR = 3.040, 95% CI 1.522-6.061, P = 0.002; and OR = 2.890, 95% CI 1.199-6.993, P = 0.018, respectively).

CONCLUSIONS

This is the first study to explore the association of mtDNA variants with individual's risk of developing severe COVID-19. Based on the case-control study, we concluded that the common mtDNA variants at C5178a and A249d/T6392C/G10310A might contribute to an individual's resistance to developing severe COVID-19, whereas A4833G, A4715G, T3394C and G5417A/C16257a/C16261T might increase an individual's risk of developing severe COVID-19.

Platelets and COVID-19

In 2019 first reports about a new human coronavirus emerged, which causes common cold symptoms as well as acute respiratory distress syndrome. The virus was identified as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and severe thrombotic events including deep vein thrombosis, pulmonary embolism, and microthrombi emerged as additional symptoms. Heart failure, myocardial infarction, myocarditis, and stroke have also been observed. As main mediator of thrombus formation, platelets became one of the key aspects in SARS-CoV-2 research. Platelets may also directly interact with SARS-CoV-2 and have been shown to carry the SARS-CoV-2 virus. Platelets can also facilitate the virus uptake by secretion of the subtilisin-like proprotein convertase furin. Cleavage of the SARS-CoV-2 spike protein by furin enhances binding capabilities and virus entry into various cell types. In COVID-19 patients, platelet count differs between mild and serious infections. Patients with mild symptoms have a slightly increased platelet count, whereas thrombocytopenia is a hallmark of severe COVID-19 infections. Low platelet count can be attributed to platelet apoptosis and the incorporation of platelets into microthrombi (peripheral consumption) and severe thrombotic events. The observed excessive formation of thrombi is due to hyperactivation of platelets caused by the infection. Various factors have been suggested in the activation of platelets in COVID-19, such as hypoxia, vessel damage, inflammatory factors, NETosis, SARS-CoV-2 interaction, autoimmune reactions, and autocrine activation. COVID-19 does alter chemokine and cytokine plasma concentrations. Platelet chemokine profiles are altered in COVID-19 and contribute to the described chemokine storms observed in severely ill COVID-19 patients.

Post-COVID-19 acute sarcopenia: physiopathology and management

In this review, we discuss the pathophysiologic and management aspects of acute sarcopenia in relation to SARS-CoV-2 infection. COVID-19 is as a multi-organ infectious disease characterized by a severe inflammatory and highly catabolic status, influencing the deep changes in the body build, especially the amount, structure, and function of skeletal muscles which would amount to acutely developed sarcopenia. Acute sarcopenia may largely impact patients’ in-hospital prognosis as well as the vulnerability to the post-COVID-19 functional and physical deterioration. The individual outcome of the COVID-19 and the degree of muscle mass and functional loss may be influenced by multiple factors, including the patient’s general pre-infection medical and functional condition, especially in older adults. This paper gathers the information about how the SARS-CoV-2 hyper-inflammatory involvement exacerbates the immunosenescence process, enhances the endothelial damage, and due to mitochondrial dysfunction and autophagy, induces myofibrillar breakdown and muscle degradation. The aftermath of these acute and complex immunological SARS-CoV-2-related phenomena, augmented by anosmia, ageusia and altered microbiota may lead to decreased food intake and exacerbated catabolism. Moreover, the imposed physical inactivity, lock-down, quarantine or acute hospitalization with bedrest would intensify the acute sarcopenia process. All these deleterious mechanisms must be swiftly put to a check by a multidisciplinary approach including nutritional support, early physical as well cardio-pulmonary rehabilitation, and psychological support and cognitive training. The proposed holistic and early management of COVID-19 patients appears essential to minimize the disastrous functional outcomes of this disease and allow avoiding the long COVID-19 syndrome.

Iron oxide nanoparticles augment the intercellular mitochondrial transfer-mediated therapy

The transfer of mitochondria between cells has recently been revealed as a spontaneous way to protect the injured cells. However, the utilization of this natural transfer process for disease treatment is so far limited by its unsatisfactory transfer efficiency and selectivity. Here, we demonstrate that iron oxide nanoparticles (IONPs) can augment the intercellular mitochondrial transfer from human mesenchymal stem cells (hMSCs) selectively to diseased cells, owing to the enhanced formation of connexin 43–containing gap junctional channels triggered by ionized IONPs. In a mouse model of pulmonary fibrosis, the IONP-engineered hMSCs achieve a remarkable mitigation of fibrotic progression because of the promoted intercellular mitochondrial transfer, with no serious safety issues identified. The present study reports a potential method of using IONPs to enable hMSCs for efficient and safe transfer of mitochondria to diseased cells to restore mitochondrial bioenergetics.

Susceptibility of lung cancer patients to COVID-19: A review of the pandemic data from multiple nationalities

Several studies have highlighted that cancer patients tend to be more susceptible to develop severe infection and to die from COVID-19. Certain medical conditions such as immunosuppression, presence of comorbidities, and underlying pulmonary damage are possible determinants of disease severity, especially in lung cancer patients. While recent studies have shown that lung cancer is one of the most prevalent tumor types among COVID-19 cancer patients, we still have an incomplete view of how data from several countries work as a whole. The aim of this review was to investigate COVID-19 prevalence in lung cancer patient cohorts and their probability to develop severe illness and death when compared to nonlung cancer patients from multiple nationalities, including countries that have been the epicenters of the pandemic. We also focus on some intrinsic lung cancer features that might influence COVID-19 outcomes. An integrative view of the susceptibility of lung cancer patients might be especially relevant to assist physicians in evaluating the risks of COVID-19 in these patients, and to foster better decisions on treatment delay.

Microbiota and Its Impact on the Immune System in COVID-19-A Narrative Review

The microbiota is of interest for the development of a therapeutic strategy against SARS-CoV-2 coronavirus disease 2019 (COVID-19) due to its impact on the host immune system. Proven communications of the gut microbiota with the pulmonary microbiota (gut-lung axis) and the pathway of neural connections between the gut and brain (gut-brain axis) may be important in the face of the pandemic. SARS-CoV-2 was shown to affect almost all organs because of the presence of a host receptor known as angiotensin converting enzyme 2 (ACE2). The ACE2 receptor is mainly present in the brush border of intestinal enterocytes, ciliary cells, and type II alveolar epithelial cells in the lungs. The transport function of ACE2 has been linked to the ecology of gut microbes in the digestive tract, suggesting that COVID-19 may be related to the gut microbiota. The severity of COVID-19 may be associated with a number of comorbidities, such as hypertension, diabetes, obesity, and/or old age; therefore, attention is also paid to multiple morbidities and the modulation of microbiota through comorbidities and medications. This paper reviews the research in the context of the state of the intestinal microbiota and its impact on the cells of the immune system during the SARS-CoV-2 pandemic.

Sub-Cellular Metabolomics Contributes Mitochondria-Specific Metabolic Insights to a Mouse Model of Leigh Syndrome

Direct injury of mitochondrial respiratory chain (RC) complex I by Ndufs4 subunit mutations results in complex I deficiency (CID) and a progressive encephalomyopathy, known as Leigh syndrome. While mitochondrial, cytosolic and multi-organelle pathways are known to be involved in the neuromuscular LS pathogenesis, compartment-specific metabolomics has, to date, not been applied to murine models of CID. We thus hypothesized that sub-cellular metabolomics would be able to contribute organelle-specific insights to known Ndufs4 metabolic perturbations. To that end, whole brains and skeletal muscle from late-stage Ndufs4 mice and age/sex-matched controls were harvested for mitochondrial and cytosolic isolation. Untargeted ¹H-NMR and semi-targeted LC-MS/MS metabolomics was applied to the resulting cell fractions, whereafter important variables (VIPs) were selected by univariate statistics. A predominant increase in multiple targeted amino acids was observed in whole-brain samples, with a more prominent effect at the mitochondrial level. Similar pathways were implicated in the muscle tissue, showing a greater depletion of core metabolites with a compartment-specific distribution, however. The altered metabolites expectedly implicate altered redox homeostasis, alternate RC fueling, one-carbon metabolism, urea cycling and dysregulated proteostasis to different degrees in the analyzed tissues. A first application of EDTA-chelated magnesium and calcium measurement by NMR also revealed tissue- and compartment-specific alterations, implicating stress response-related calcium redistribution between neural cell compartments, as well as whole-cell muscle magnesium depletion. Altogether, these results confirm the ability of compartment-specific metabolomics to capture known alterations related to Ndufs4 KO and CID while proving its worth in elucidating metabolic compartmentalization in said pathways that went undetected in the diluted whole-cell samples previously studied.

Diet, Probiotics and Their Impact on the Gut Microbiota during the COVID-19 Pandemic

SARS-CoV-2 infection is associated with diverse clinical manifestations, immune dysfunction, and gut microbiota alterations. The nutritional and biochemical quality of one's diet can influence the intestinal microbiota, which may play a role in the defense mechanisms against potential pathogens, by promoting a wide variety of immune-host interactions. In the COVID-19 pandemic, besides the development of pharmacological therapies, a healthy balanced diet, rich with food-derived antioxidants, may be a useful strategy. Many studies demonstrated that vitamins and probiotic therapies have positive effects on the treatment and prevention of oxidative stress and inflammation in COVID-19. The ecology of the gut microbiota in the digestive tract has been linked to the transport function of the host receptor known as angiotensin converting enzyme 2 (ACE2), suggesting that COVID-19 may be related to the gut microbiota. The angiotensin converting enzyme (ACE), and its receptor (ACE2), play central roles in modulating the renin-angiotensin system (RAS). In addition, ACE2 has functions that act independently of the RAS. ACE2 is the receptor for the SARS coronavirus, and ACE2 is essential for the expression of neutral amino acid transporters in the gut. In this context, ACE2 modulates innate immunity and influences the composition of the gut microbiota. Malnutrition is one of the leading underlying causes of morbidity and mortality worldwide and, including comorbidities, may be a major cause of worse outcomes and higher mortality among COVID-19 patients. This paper reviews the research on dietary components, with particular emphasis on vitamins, antioxidants, and probiotic therapies, and their impacts on the intestinal microbiota's diversity during the SARS-CoV-2 pandemic.

Changes in Glycolytic Pathway in SARS-COV 2 Infection and Their Importance in Understanding the Severity of COVID-19

COVID-19 is an infectious disease caused by Coronavirus 2 (SARS-CoV-2) that may lead to a severe acute respiratory syndrome. Such syndrome is thought to be related, at least in part, to a dysregulation of the immune system which involves three main components: hyperactivity of the innate immune system; decreased production of type 1 Interferons (IFN) by SARS-CoV-2-infected cells, namely respiratory epithelial cells and macrophages; and decreased numbers of both CD4+ and particularly CD8+ T cells. Herein, we describe how excessive activation of the innate immune system and the need for viral replication in several cells of the infected organism promote significant alterations in cells' energy metabolism (glucose metabolism), which may underlie the poor prognosis of the disease in severe situations. When activated, cells of the innate immune system reprogram their metabolism, and increase glucose uptake to ensure secretion of pro-inflammatory cytokines. Changes in glucose metabolism are also observed in pulmonary epithelial cells, contributing to dysregulation of cytokine synthesis and inflammation of the pulmonary epithelium. Controlling hyperglycolysis in critically ill patients may help to reduce the exaggerated production of pro-inflammatory cytokines and optimise the actions of the adaptive immune system. In this review, we suggest that the administration of non-toxic concentrations of 2-deoxy-D-glucose, the use of GLUT 1 inhibitors, of antioxidants such as vitamin C in high doses, as well as the administration of N-acetylcysteine in high doses, may be useful complementary therapeutic strategies for these patients, as suggested by some clinical trials and/ or reports. Overall, understanding changes in the glycolytic pathway associated with COVID-19 infection can help to find new forms of treatment for this disease.

Mitochondria and Mitochondrial DNA: Key Elements in the Pathogenesis and Exacerbation of the Inflammatory State Caused by COVID-19

Background and Objectives. The importance of mitochondria in inflammatory pathologies, besides providing energy, is associated with the release of mitochondrial damage products, such as mitochondrial DNA (mt-DNA), which may perpetuate inflammation. In this review, we aimed to show the importance of mitochondria, as organelles that produce energy and intervene in multiple pathologies, focusing mainly in COVID-19 and using multiple molecular mechanisms that allow for the replication and maintenance of the viral genome, leading to the exacerbation and spread of the inflammatory response. The evidence suggests that mitochondria are implicated in the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which forms double-membrane vesicles and evades detection by the cell defense system. These mitochondrion-hijacking vesicles damage the integrity of the mitochondrion’s membrane, releasing mt-DNA into circulation and triggering the activation of innate immunity, which may contribute to an exacerbation of the pro-inflammatory state. Conclusions. While mitochondrial dysfunction in COVID-19 continues to be studied, the use of mt-DNA as an indicator of prognosis and severity is a potential area yet to be explored.

Can healthy lifestyle reduce disease progression of Alzheimer's during a global pandemic of COVID-19?

The novel coronavirus disease 2019 (COVID-19) has pushed the medical system to its breaking point. While the virus does not discriminate, the elderly and those with comorbidities, including hypertension severe obesity, diabetes mellitus, coronary disease, pneumonia and dementia, are at a greater risk for adverse outcomes due to COVID-19. While many people navigate their new normal, the question of what the long-lasting effects of the pandemic may be, lingers. To investigate how vulnerable populations are affected by the pandemic, we focused on Alzheimer's disease, a vector to understanding how the virus has impacted AD progression and risk via aging. By assessing the effect of COVID-19 on AD patients, we explore genetics, metabolism, and lifestyle factors in both COVID-19 and Alzheimer's disease that can work synergistically to precipitate adverse outcomes. This article also discusses how age-related conditions and/or age-related comorbidities susceptible to COVID-19. We also discuss possible healthy lifestyle factors reduce and/or combat COVID-19 now and in the future.

Combined Metabolic Activators Accelerates Recovery in Mild-to-Moderate COVID-19

COVID-19 is associated with mitochondrial dysfunction and metabolic abnormalities, including the deficiencies in nicotinamide adenine dinucleotide (NAD+ ) and glutathione metabolism. Here it is investigated if administration of a mixture of combined metabolic activators (CMAs) consisting of glutathione and NAD+ precursors can restore metabolic function and thus aid the recovery of COVID-19 patients. CMAs include l-serine, N-acetyl-l-cysteine, nicotinamide riboside, and l-carnitine tartrate, salt form of l-carnitine. Placebo-controlled, open-label phase 2 study and double-blinded phase 3 clinical trials are conducted to investigate the time of symptom-free recovery on ambulatory patients using CMAs. The results of both studies show that the time to complete recovery is significantly shorter in the CMA group (6.6 vs 9.3 d) in phase 2 and (5.7 vs 9.2 d) in phase 3 trials compared to placebo group. A comprehensive analysis of the plasma metabolome and proteome reveals major metabolic changes. Plasma levels of proteins and metabolites associated with inflammation and antioxidant metabolism are significantly improved in patients treated with CMAs as compared to placebo. The results show that treating patients infected with COVID-19 with CMAs lead to a more rapid symptom-free recovery, suggesting a role for such a therapeutic regime in the treatment of infections leading to respiratory problems.

Redox imbalance links COVID-19 and myalgic encephalomyelitis/chronic fatigue syndrome

Although most patients recover from acute COVID-19, some experience postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection (PASC). One subgroup of PASC is a syndrome called "long COVID-19," reminiscent of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). ME/CFS is a debilitating condition, often triggered by viral and bacterial infections, leading to years-long debilitating symptoms including profound fatigue, postexertional malaise, unrefreshing sleep, cognitive deficits, and orthostatic intolerance. Some are skeptical that either ME/CFS or long COVID-19 involves underlying biological abnormalities. However, in this review, we summarize the evidence that people with acute COVID-19 and with ME/CFS have biological abnormalities including redox imbalance, systemic inflammation and neuroinflammation, an impaired ability to generate adenosine triphosphate, and a general hypometabolic state. These phenomena have not yet been well studied in people with long COVID-19, and each of them has been reported in other diseases as well, particularly neurological diseases. We also examine the bidirectional relationship between redox imbalance, inflammation, energy metabolic deficits, and a hypometabolic state. We speculate as to what may be causing these abnormalities. Thus, understanding the molecular underpinnings of both PASC and ME/CFS may lead to the development of novel therapeutics.

Immune System Disequilibrium-Neutrophils, Their Extracellular Traps, and COVID-19-Induced Sepsis

Equilibrium within the immune system can often determine the fate of its host. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the pathogen responsible for the coronavirus disease 2019 (COVID-19) pandemic. Immune dysregulation remains one of the main pathophysiological components of SARS-CoV-2-associated organ injury, with over-activation of the innate immune system, and induced apoptosis of adaptive immune cells. Here, we provide an overview of the innate immune system, both in general and relating to COVID-19. We specifically discuss "NETosis," the process of neutrophil release of their extracellular traps, which may be a more recently described form of cell death that is different from apoptosis, and how this may propagate organ dysfunction in COVID-19. We complete this review by discussing Stem Cell Therapies in COVID-19 and emerging COVID-19 phenotypes, which may allow for more targeted therapy in the future. Finally, we consider the array of potential therapeutic targets in COVID-19, and associated therapeutics.

A review on corona virus and treatment approaches with Allium sativam

Background

Recently reported cases of Covid-19 globally remind us that new diseases are coming while we are unable to provide the treatment for the same. The entire world is facing this viral attack; deaths are increasing day by day as well as infected patients too. Today, in the period of this disease, can we go to the shelter of our traditional medicines?

Main body

In this article, we have taken medicines related to corona and conceptualized their mechanism, which gave us a chance to understand Garlic's mechanism of action, how Garlic can be a weapon in the lane with this disease. This article also tells how we can treat new diseases with our traditional herbs if no modern medicine has been discovered yet.

Conclusion

The present review is based on the structure of the virus and the targeted site for the drug discovery process with important constituents of Allium sativam. The review work also explains the allicin chemical constituent of Allium sativam which has targeted therapeutic sites related to Covid-19.

[Gastroenterological symptoms in COVID-19 patients with mild severity of the disease: opportunities to optimize antidiarrheal therapy]

BACKGROUND

The novel coronavirus infection COVID-19 can be manifested by damage to the organs of the gastrointestinal tract (GIT). Damage to the gastrointestinal tract by the SARS-CoV-2 virus leads to a violation of the microbial-tissue complex of the mucous membrane of the digestive tract. A common gastroenterological manifestation of COVID-19 is diarrhea.

AIM

Study of the clinical features of gastroenterological disorders and the possibility of optimizing the treatment of diarrheal syndrome in patients with COVID-19 with a mild form of viral infection.

MATERIALS AND METHODS

The observation group consisted of 230 patients with mild COVID-19: K-group (n=115) with respiratory symptoms, I group (n=115) with gastrointestinal manifestations in combination and without signs of respiratory damage. In order to compare the effectiveness of treatment of diarrheal syndrome, patients of group I are randomized into 2 subgroups: Ia (n=58) prebiotic treatment (Zacofalk) and Ib (n=57) enterosorbents.

RESULTS

The development of gastrointestinal symptoms with SARS-CoV-2 infection is significantly more often noted in comorbid patients (67%). Gastrointestinal symptoms were dominated by diarrhea (93.9%) and flatulence (76.5%), in 1/3 of patients they were the first manifestos of infection. It was established that in 98.4% of patients of group I (against 42.6% of the K-group) signs of infectious intoxication were detected. In patients with gastrointestinal lesions, an elongation of the febrile period by 91.5 days was noted, a later (6 days) verification of the viral etiology of the disease. It was found that in patients of group I, the regression of clinical symptoms, the duration of viral disease, the dynamics of antibody formation, the prognosis for the development of IBS-like disorders in the post-infectious period depended on the treatment. In patients taking (Zacofalk), these indicators were significantly better.

CONCLUSION

In mild cases, to reduce the severity of viral intestinal damage, for effective relief of intestinal symptoms, to reduce the risk of IBS-like symptoms, it is advisable to prescribe (Zacofalk) in an initial dose of 3 tablets per day.

Lower Serum Angiotensin-Converting Enzyme Level in Relation to Hyperinflammation and Impaired Antiviral Immune Response Contributes to Progression of COVID-19 Infection

INTRODUCTION

As a homologue of the angiotensin-converting enzyme (ACE), angiotensin-converting enzyme 2 (ACE2) has been identified as the main receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) invasion. We aimed to investigate the role of serum ACE in predicting the coronavirus disease 2019 (COVID-19) disease progression and the underlying mechanisms.

METHODS

We retrospectively enrolled 120 patients with confirmed COVID-19 who underwent serum ACE detection on admission. The clinical characteristics and laboratory findings during hospitalization were evaluated dynamically to identify the potential risk factors for disease progression.

RESULTS

ACE level was demonstrated as one of the independent risk factors. Patients with ACE level ≤ 33.5 U/L showed a higher cumulative virus RNA detection rate, elevated pro-inflammatory mediators levels, declined lymphocyte count, and decreased SARS-CoV-2-specific antibodies than those with ACE level > 33.5 U/L.

CONCLUSION

Lower serum ACE levels in relation to delayed virus elimination, hyperinflammatory condition, and impaired host antiviral immune responses contribute to disease progression of COVID-19.

Mitochondrial DNA in innate immune responses against infectious diseases

Mitochondrial DNA (mtDNA) can initiate an innate immune response when mislocalized in a compartment other than the mitochondrial matrix. mtDNA plays significant roles in regulating mitochondrial dynamics as well as mitochondrial unfolded protein response (UPR). The mislocalized extra-mtDNA can elicit innate immune response via cGAS-STING (cyclic GMP-AMP synthase-stimulator of interferon genes) pathway, inducing the expression of the interferon-stimulated genes (ISGs). Also, cytosolic damaged mtDNA is cleared up by various pathways which are responsible for participating in the activation of inflammatory responses. Four pathways of extra-mitochondrial mtDNA clearance are highlighted in this review - the inflammasome activation mechanism, neutrophil extracellular traps formation, recognition by Toll-like receptor 9 and transfer of mtDNA between cells packaged into extracellular vesicles. Anomalies in these pathways are associated with various diseases. We posit our review in the present pandemic situation and discuss how mtDNA elicits innate immune responses against different viruses and bacteria. This review gives a comprehensive picture of the role of extra-mitochondrial mtDNA in infectious diseases and speculates that research towards its understanding would help establish its therapeutic potential.

Emerging potential mechanisms and predispositions to the neurological manifestations of COVID-19

A spectrum of neurological disease associated with COVID-19 is becoming increasingly apparent. However, the mechanisms behind these manifestations remain poorly understood, significantly hindering their management. The present review subsequently attempts to address the evolving molecular, cellular and systemic mechanisms of NeuroCOVID, which we have classified as the acute and long-term neurological effects of COVID-19. We place particular emphasis on cerebrovascular, demyelinating and encephalitic presentations, which have been reported. Several mechanisms are presented, especially the involvement of a "cytokine storm". We explore the genetic and demographic factors that may predispose individuals to NeuroCOVID. The increasingly evident long-term neurological effects are also presented, including the impact of the virus on cognition, autonomic function and mental wellbeing, which represent an impending burden on already stretched healthcare services. We subsequently reinforce the need for cautious surveillance, especially for those with predisposing factors, with effective clinical phenotyping, appropriate investigation and, if possible, prompt treatment. This will be imperative to prevent downstream neurological sequelae, including those related to the long COVID phenotypes that are being increasingly recognised.

Mitochondria Can Cross Cell Boundaries: An Overview of the Biological Relevance, Pathophysiological Implications and Therapeutic Perspectives of Intercellular Mitochondrial Transfer

Mitochondria are complex intracellular organelles traditionally identified as the powerhouses of eukaryotic cells due to their central role in bioenergetic metabolism. In recent decades, the growing interest in mitochondria research has revealed that these multifunctional organelles are more than just the cell powerhouses, playing many other key roles as signaling platforms that regulate cell metabolism, proliferation, death and immunological response. As key regulators, mitochondria, when dysfunctional, are involved in the pathogenesis of a wide range of metabolic, neurodegenerative, immune and neoplastic disorders. Far more recently, mitochondria attracted renewed attention from the scientific community for their ability of intercellular translocation that can involve whole mitochondria, mitochondrial genome or other mitochondrial components. The intercellular transport of mitochondria, defined as horizontal mitochondrial transfer, can occur in mammalian cells both in vitro and in vivo, and in physiological and pathological conditions. Mitochondrial transfer can provide an exogenous mitochondrial source, replenishing dysfunctional mitochondria, thereby improving mitochondrial faults or, as in in the case of tumor cells, changing their functional skills and response to chemotherapy. In this review, we will provide an overview of the state of the art of the up-to-date knowledge on intercellular trafficking of mitochondria by discussing its biological relevance, mode and mechanisms underlying the process and its involvement in different pathophysiological contexts, highlighting its therapeutic potential for diseases with mitochondrial dysfunction primarily involved in their pathogenesis.

Computational assessment of saikosaponins as adjuvant treatment for COVID-19: molecular docking, dynamics, and network pharmacology analysis

Saikosaponins are major biologically active triterpenoids, usually as glucosides, isolated from Traditional Chinese Medicines (TCM) such as Bupleurum spp., Heteromorpha spp., and Scrophularia scorodonia with their antiviral and immunomodulatory potential. This investigation presents molecular docking, molecular dynamics simulation, and free energy calculation studies of saikosaponins as adjuvant therapy in the treatment for COVID19. Molecular docking studies for 23 saikosaponins on the crystal structures of the extracellular domains of human lnterleukin-6 receptor (IL6), human Janus Kinase-3 (JAK3), and dehydrogenase domain of Cylindrospermum stagnale NADPH-oxidase 5 (NOX5) were performed, and selected protein-ligand complexes were subjected to 100 ns molecular dynamics simulations. The molecular dynamics trajectories were subjected to free energy calculation by the MM-GBSA method. Molecular docking and molecular dynamics simulation studies revealed that IL6 in complex with Saikosaponin_U and Saikosaponin_V, JAK3 in complex with Saikosaponin_B4 and Saikosaponin_I, and NOX5 in complex with Saikosaponin_BK1 and Saikosaponin_C have good docking and molecular dynamics profiles. However, the Janus Kinase-3 is the best interacting partner for the saikosaponin compounds. The network pharmacology analysis suggests saikosaponins interact with the proteins CAT Gene CAT (Catalase) and Checkpoint kinase 1 (CHEK1); both of these enzymes play a major role in cell homeostasis and DNA damage during infection, suggesting a possible improvement in immune response toward COVID-19.

Impact of maternal nutrition in viral infections during pregnancy

Other than being a physiological process, pregnancy is a condition characterized by major adaptations of maternal endocrine and metabolic homeostasis that are necessary to accommodate the fetoplacental unit. Unfortunately, all these systemic, cellular, and molecular changes in maternal physiology also make the mother and the fetus more prone to adverse outcomes, including numerous alterations arising from viral infections. Common infections during pregnancy that have long been recognized as congenitally and perinatally transmissible to newborns include toxoplasmosis, rubella, cytomegalovirus, and herpes simplex viruses (originally coined as ToRCH infections). In addition, enterovirus, parvovirus B19, hepatitis virus, varicella-zoster virus, human immunodeficiency virus, Zika and Dengue virus, and, more recently, coronavirus infections including Middle Eastern respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS) infections (especially the novel SARS-CoV-2 responsible for the ongoing COVID-19 pandemic), constitute relevant targets for current research on maternal-fetal interactions in viral infections during pregnancy. Appropriate maternal education from preconception to the early postnatal period is crucial to promote healthy pregnancies in general and to prevent and/or reduce the impact of viral infections in particular. Specifically, an adequate lifestyle based on proper nutrition plans and feeding interventions, whenever possible, might be crucial to reduce the risk of virus-related gestational diseases and accompanying complications in later life. Here we aim to provide an overview of the emerging literature addressing the impact of nutrition in the context of potentially harmful viral infections during pregnancy.

Is there a place for mesenchymal stromal cell-based therapies in the therapeutic armamentarium against COVID-19?

The COVID-19 pandemic, caused by the rapid global spread of the novel coronavirus (SARS-CoV-2), has caused healthcare systems to collapse and led to hundreds of thousands of deaths. The clinical spectrum of COVID-19 is not only limited to local pneumonia but also represents multiple organ involvement, with potential for systemic complications. One year after the pandemic, pathophysiological knowledge has evolved, and many therapeutic advances have occurred, but mortality rates are still elevated in severe/critical COVID-19 cases. Mesenchymal stromal cells (MSCs) can exert immunomodulatory, antiviral, and pro-regenerative paracrine/endocrine actions and are therefore promising candidates for MSC-based therapies. In this review, we discuss the rationale for MSC-based therapies based on currently available preclinical and clinical evidence of safety, potential efficacy, and mechanisms of action. Finally, we present a critical analysis of the risks, limitations, challenges, and opportunities that place MSC-based products as a therapeutic strategy that may complement the current arsenal against COVID-19 and reduce the pandemic's unmet medical needs.

Little in vitro effect of remdesivir on mitochondrial respiration and monoamine oxidase activity in isolated mitochondria

Remdesivir (RDV) is a novel antiviral drug whose mitochondrial effects are not well known. In vitro effects of RDV on the mitochondrial respiration, individual respiratory complexes, and the activity of monoamine oxidase (MAO-A and MAO-B) were measured in isolated mitochondria. At micromolar RDV concentrations, minimal or no inhibitory effects on the studied mitochondrial enzymes were found. At very high concentrations of RDV, there was partial inhibition of complex I- (IC₅₀ 675 μmol/L, residual activity 39.4 %) and complex II-linked (IC₅₀ 81.8 μmol/L, residual activity 40.7 %) respiration, without inhibition of complex IV-linked respiration, and partial inhibition both of MAO-A (IC₅₀ 26.6 μmol/L, residual activity 35.2 %) and MAO-B (IC₅₀ 89.8 μmol/L, residual activity 34.0 %) activity. Individual respiratory complexes (I, II + III, and IV) were partially inhibited at a high drug concentration. The active metabolite of RDV (GS-443902) had very little effect on mitochondrial oxygen consumption rate with residual activity of 87.0 % for complex I-linked respiration, 90.3 % for complex II-linked respiration, and with no inhibition of complex IV-linked respiration. In conclusion, measurement of the effect of RDV and its active metabolite on isolated mitochondria shows that there is very little direct effect on mitochondrial respiration occurs at therapeutic drug concentration.

Cardiopulmonary exercise testing in COVID-19 patients at 3 months follow-up

Background

Long-term effects of Coronavirus Disease of 2019 (COVID-19) are of utmost relevance.

We aimed to determine: 1) the functional capacity of COVID-19 survivors by cardiopulmonary exercise testing (CPET); 2) the characteristics associated with cardiopulmonary exercise testing (CPET) performance; 3) the safety and tolerability of CPET.

Methods

We prospectively enrolled consecutive patients with laboratory-confirmed COVID-19 from Azienda Sanitaria Locale 3, Genoa. Three months after hospital discharge a complete clinical evaluation, trans-thoracic echocardiography, CPET, pulmonary function tests, and dominant leg extension (DLE) maximal strength measurement were performed.

Results

From the 225 patients discharged alive from March to November 2020, we excluded 12 incomplete/missing cases and 13 unable to perform CPET, leading to a final cohort of 200. Median percent-predicted peak oxygen uptake (%pVO2) was 88% (78.3–103.1).

Ninety-nine (49.5%) patients had %pVO2 below, whereas 101 (50.5%) above the 85% predicted value.

Among the 99 patients with reduced %pVO2, 61 (61%) had a normal anaerobic threshold: of these, 9(14.8%) had respiratory, 21(34.4%) cardiac, and 31(50.8%) non-cardiopulmonary reasons for exercise limitation. Inerestingly, 80% of patients experienced at least one disabling symtpom, not related to %pVO2 or functional capacity.

Multivariate linear regression showed percent-predicted forced expiratory volume in one-second(β = 5.29,p = 0.023), percent-predicted diffusing capacity of lungs for carbon monoxide(β = 6.31,p = 0.001), and DLE maximal strength(β = 14.09,p = 0.008) to be independently associated with pVO2.

No adverse event was reported during or after CPET, and no involved health professional developed COVID-19.

Conclusions

At three months after discharge, about 1/3rd of COVID-19 survivors show functional limitations, mainly explained by muscular impairment, calling for future research to identify patients at higher risk of long-term effects that may benefit from careful surveillance and targeted rehabilitation.

Serum Metabolic Profile in Patients With Long-Covid (PASC) Syndrome: Clinical Implications

Background: Many patients who have been suffering by Covid-19 suffer of long-Covid syndrome, with symptoms of fatigue and muscular weakness that characterize post-acute sequelae SARS-CoV-2 infection (PASC). However, there is limited knowledge about the molecular pathophysiology, and about the serum profile of these patients. Methods: We studied the blood serum profile of 75 selected patients, with previous confirmed Covid-19, 2 months after hospital discharge, who reported new-onset fatigue, muscle weakness and/or dyspnea not present prior to the virus infection and independently from concomitant diseases and/or clinical conditions. Results: All patients had very high serum concentrations of ferritin and D-Dimer. 87 and 72% of patients had clinically significant low levels of hemoglobin and albumin, respectively. Seventy three percentage had elevations in erythrocyte sedimentation rate and CRP. Twenty seven percentage had elevations in LDH. Conclusions: The co-existence of patient symptoms along with blood markers of coagulation, protein disarrangement and inflammation suggests ongoing alterations in the metabolism, promoting an inflammatory/hypercatabolic state which maintains a vicious circles implicated in the persistence of PASC. The persistence of altered D-Dimer levels raises the possibility of long-term risks of thromboembolic disease. All these markers levels should be accurately evaluated in the long-term follow-up, with individualized consideration for prophylactic nutritional, anti-inflammatory and/or anticoagulant therapy if indicated.

Investigating the potential mechanisms of depression induced-by COVID-19 infection in patients

The new coronavirus (COVID-19) has emerged now in the world as a pandemic. The SARS-CoV-2 infection causes variant common symptoms, such as dry cough, tiredness, dyspnea, fever, myalgia, chills, headache, chest pain, and conjunctivitis. Different organs may be affected by COVID-19, such as the respiratory system, gastrointestinal tract, kidneys, and CNS. However, the information about the COVID-19 infection in the CNS is insufficient. We do know that the virus can enter the central nervous system (CNS) via different routes, causing symptoms such as dizziness, headache, seizures, loss of consciousness, and depression. Depression is the most common disorder among all neurological symptoms following COVID-19 infection, although the mechanism of COVID-19-induced depression is not yet clear.

The aim of the present study is to investigate the probable mechanisms of COVID-19-induced depression.

The reasons for depression in infected patients may be due to social and pathological factors including social quarantine, economic problems, stress, changes in the HPA axis, inflammation due to the entry of proinflammatory cytokines into the CNS, production of inflammatory cytokines by microglia, mitochondrial disorders, damage to the hippocampus, and malnutrition.

By evaluating different factors involved in COVID-19-induced depression, we have concluded that depression can be minimized by controlling stress, preventing the cytokine storm with appropriate anti-inflammatory drugs, and proper nutrition.

Work Stress, Dysbiosis, and Immune Dysregulation: The Interconnected Triad in COVID-19 Infection in the Medical Team Staff - A Mini-Review

The COVID-19 pandemic has hit most of the communities around the globe. Earlier researches have reported the psychological effects of pandemics either on the general populations or on specific communities such as students and health professionals. A scanty number of papers have focused on the interaction among complex factors underlying the pathogenesis of the disease. In this review, we aimed to integrate the accessible data about the possible mechanistic processes predisposing to COVID-19 infection in the health professions. We summarized these factors as "stress, microbiota, and immunity triad." We utilized the PubMed database, Google, and Google Scholar search engines to search the literature related to combinations of these keywords: "pandemics, COVID-19, coronavirus, SARS-CoV2;" "gut microbiota, gut-lung axis, dysbiosis, nutrition;" "work stress, workload, health workers, health professions, and medical team;" and "immunity, cytokine storm, and viral load." We detected no discussions combining the suggested triad concerning the medical team personnel. We cast light, for the first time to our knowledge, on the potential pathogenic role of "stress, microbiota, and immunity triad" in COVID-19-infected health workers.

Knockdown of VDAC1 alleviates the cognitive dysfunction secondary to sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE) is a serious and diffuse cerebral dysregulation with a high morbidity and mortality caused by sepsis. Mitophagy plays an important role in SAE, and microglial phagocytosis of apoptotic cells (efferocytosis) is the core of the brain regenerative response. Voltage dependent anion channel (VDAC1) is an important regulator of mitophagy. However, it remains unknown whether VDAC1 influences SAE progression by regulating mitophagy and efferocytosis. Herein, we explored the mechanism where knockdown of VDAC1 alleviated the cognitive dysfunction caused by sepsis-associated encephalopathy and further elucidated the underlying molecular mechanisms. SAE model in mice was established through caecal ligation and puncture (CLP). The increased mitophagy and decreased efferocytosis were observed by the transmission electron microscope (TEM) in the SAE model. Besides, immunoblot tests showed an interaction between autophagy and efferocytosis. Further behavior tests and TEM results indicated that knockdown of VDAC1 alleviated the cognitive dysfunction by decreasing the autophagy and increasing the efferocytosis in a PINK1/Parkin-dependent manner. Based on these results, we conclude that knockdown of VDAC1 alleviates the cognitive dysfunction in the CLP-induced SAE mouse model.

The central role of mitochondrial fitness on antiviral defenses: An advocacy for physical activity during the COVID-19 pandemic

Mitochondria are central regulators of cellular metabolism, most known for their role in energy production. They can be "enhanced" by physical activity (including exercise), which increases their integrity, efficiency and dynamic adaptation to stressors, in short "mitochondrial fitness". Mitochondrial fitness is closely associated with cardiorespiratory fitness and physical activity. Given the importance of mitochondria in immune functions, it is thus not surprising that cardiorespiratory fitness is also an integral determinant of the antiviral host defense and vulnerability to infection. Here, we first briefly review the role of physical activity in viral infections. We then summarize mitochondrial functions that are relevant for the antiviral immune response with a particular focus on the current Coronavirus Disease (COVID-19) pandemic and on innate immune function. Finally, the modulation of mitochondrial and cardiorespiratory fitness by physical activity, aging and the chronic diseases that represent the most common comorbidities of COVID-19 is discussed. We conclude that a high mitochondrial - and related cardiorespiratory - fitness should be considered as protective factors for viral infections, including COVID-19. This assumption is corroborated by reduced mitochondrial fitness in many established risk factors of COVID-19, like age, various chronic diseases or obesity. We argue for regular analysis of the cardiorespiratory fitness of COVID-19 patients and the promotion of physical activity - with all its associated health benefits - as preventive measures against viral infection.

Clinical Significance of Micronutrient Supplementation in Critically Ill COVID-19 Patients with Severe ARDS

The interplay between inflammation and oxidative stress is a vicious circle, potentially resulting in organ damage. Essential micronutrients such as selenium (Se) and zinc (Zn) support anti-oxidative defense systems and are commonly depleted in severe disease. This single-center retrospective study investigated micronutrient levels under Se and Zn supplementation in critically ill patients with COVID-19 induced acute respiratory distress syndrome (ARDS) and explored potential relationships with immunological and clinical parameters. According to intensive care unit (ICU) standard operating procedures, patients received 1.0 mg of intravenous Se daily on top of artificial nutrition, which contained various amounts of Se and Zn. Micronutrients, inflammatory cytokines, lymphocyte subsets and clinical data were extracted from the patient data management system on admission and after 10 to 14 days of treatment. Forty-six patients were screened for eligibility and 22 patients were included in the study. Twenty-one patients (95%) suffered from severe ARDS and 14 patients (64%) survived to ICU discharge. On admission, the majority of patients had low Se status biomarkers and Zn levels, along with elevated inflammatory parameters. Se supplementation significantly elevated Se (p = 0.027) and selenoprotein P levels (SELENOP; p = 0.016) to normal range. Accordingly, glutathione peroxidase 3 (GPx3) activity increased over time (p = 0.021). Se biomarkers, most notably SELENOP, were inversely correlated with CRP (r_s = −0.495), PCT (r_s = −0.413), IL-6 (r_s = −0.429), IL-1β (r_s = −0.440) and IL-10 (r_s = −0.461). Positive associations were found for CD8⁺ T cells (r_s = 0.636), NK cells (r_s = 0.772), total IgG (r_s = 0.493) and PaO₂/FiO₂ ratios (r_s = 0.504). In addition, survivors tended to have higher Se levels after 10 to 14 days compared to non-survivors (p = 0.075). Sufficient Se and Zn levels may potentially be of clinical significance for an adequate immune response in critically ill patients with severe COVID-19 ARDS.

Use of Antioxidants for the Neuro-Therapeutic Management of COVID-19

Coronavirus Disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is an emergent infectious disease that has caused millions of deaths throughout the world. COVID-19 infection's main symptoms are fever, cough, fatigue, and neurological manifestations such as headache, myalgias, anosmia, ageusia, impaired consciousness, seizures, and even neuromuscular junctions' disorders. In addition, it is known that this disease causes a series of systemic complications such as adverse respiratory distress syndrome, cardiac injury, acute kidney injury, and liver dysfunction. Due to the neurological symptoms associated with COVID-19, damage in the central nervous system has been suggested as well as the neuroinvasive potential of SARS-CoV-2. It is known that CoV infections are associated with an inflammation process related to the imbalance of the antioxidant system; cellular changes caused by oxidative stress contribute to brain tissue damage. Although anti-COVID-19 vaccines are under development, there is no specific treatment for COVID-19 and its clinical manifestations and complications; only supportive treatments with immunomodulators, anti-vascular endothelial growth factors, modulating drugs, statins, or nutritional supplements have been used. In the present work, we analyzed the potential of antioxidants as adjuvants for the treatment of COVID-19 and specifically their possible role in preventing or decreasing the neurological manifestations and neurological complications present in the disease.

Autoimmunity and COVID-19 - The microbiotal connection

Background and aims

The novel SARS-CoV-2 has been rattling the world since its outbreak in December 2019, leading to the COVID-19 pandemic. The learning curve of this new virus has been steep, with a global scientific community desperate to learn how the virus is transmitted, how it replicates, why it causes such a wide spectrum of disease manifestations, resulting in none or few symptoms in some. Others are burdened by an intense immune response that resembles the cytokine storm syndrome (CSS), which leads to severe disease manifestations, often complicated by fatal acute respiratory distress syndrome and death. Research efforts have been focusing on finding effective cures and vaccinations for this virus.

The presence of SARS-CoV-2 in the gastrointestinal (GI) tract, represented by several GI manifestations, has led to its investigation as a target for the virus and as an indicator of disease severity. The response of the microbiome (which is heavily linked to immunity) to the novel SARS-CoV-2 virus, and its role in igniting the exaggerated immune response has therefore become a focus of interest. The objective of our study was to gather the data connecting between the microbiome, the GI tract and COVID-19 and to investigate whether these reported alterations in the gut microbiome bear any resemblance to those seen in lupus, the prototypical autoimmune disease. Confirming such changes may become the steppingstone to potential therapies that may prevent transmission, progression and immune related manifestations of COVID-19, via manipulation of the gut microbiota.

Methods

We performed an extensive literature review, utilizing the Pubmed search engine and Google Scholar for studies evaluating the microbiome in COVID-19 patients and compared results with studies evaluating the microbiome in lupus. We searched for the terms: microbiome, dysbiosis, COVID-19, SARS-CoV-2, gastrointestinal as well as lupus and autoimmune. While there were hundreds of articles which referred to gastrointestinal manifestations in COVID-19, to date only 4 studies investigated the gastrointestinal microbiome in this setting. We compared the similarities between microbiome of COVID-19 patients and lupus patients.

Results

We found that there are several similar processes of immune dysregulation in patients with COVID-19 and in those with lupus, with several other alterations seen in other pathological states. Some of these similarities include loss of microbiota biodiversity, increased representation of pathobionts, which are microbes associated with inflammation and disease (i.e Proteobacteria) and a relative decrease of symbionts, which are protective microbes, associated with anti-inflammatory properties (i.e Lactobacillus). Compromise to the intestinal barrier has also been reported in both.

Conclusions

We conclude that the gastrointestinal tract contributes to the disease manifestations in COVID-19. Whether gastrointestinal dysbiosis is the cause or effect of gastrointestinal manifestations and several severe systemic manifestations, which may be the response to an increased pro-inflammatory environment, is still debatable and warrants further investigation. Given the resemblance of the microbiome in COVID-19 patients to that seen in lupus patients, it becomes clearer why several therapies used in autoimmune conditions are currently under investigation for the treatment of COVID-19 patients. Moreover, these findings should promote further investigating the utility of manipulation of the microbiome, via nutritional supplementation or even fecal transplantations, interventions that may alter the course of the disease, and potentially prevent disease transmission at low cost and low risk.

Evaluation of oxidative stress level: total antioxidant capacity, total oxidant status and glutathione activity in patients with COVID-19

Coronavirus disease 2019 (COVID-19), as a dangerous global pandemic, has led to high morbidity and mortality in all countries. There is a lot of evidence for the possible role of oxidative stress in COVID-19. In the present study, we aimed to measure the levels of glutathione (GSH), total antioxidant capacity (TAC) and total oxidant status (TOS) in the serum of patients with COVID-19.

A total of 96 individuals with and without COVID-19 were enrolled and divided into four groups, including hospitalised group in non–intensive care units (non-ICU) (n = 35), hospitalised group in intensive care units with endotracheal intubation (EI) (ICU with EI) (n = 19), hospitalised group in intensive care units without endotracheal intubation (ICU without EI) (n = 24) and healthy people without COVID-19 disease as our control group (n = 18). The present study revealed that the TOS level was significantly lower in the group of control (p = 0.001), and level of GSH remarkably increased in the patients' groups (p < 0.001). TAC activity in non-ICU group of patients had no significant difference in comparison with the control group. However, in hospitalised patients' groups in the ICU with and without EI this activity was significantly different from the control group (p < 0.001). Moreover, there was a significant relationship between the levels of TOS, GSH and TAC with blood oxygen saturation (SpO2), fever, duration of hospitalisation and the prognosis of this disease (p < 0.001). Area under the curve (CI, 95%) of TOS, TAC and GSH-C to predict death among patients were, respectively, 0.907 (0.841, 0.973), 0.735 (0.626, 0.843) and 0.820 (0.725, 0.914). Receiver operating characteristic curve analysis showed that TOS, TAC and GSH-C have the potential specificity and sensitivity to distinguish between alive and dead patients. We found that elevated levels of oxidative stress and reduction of antioxidant indices can aggravate disease's severity in hospitalised patients with COVID-19. Therefore, it can be suggested to apply antioxidant agents as one of the effective therapeutic strategies in these groups.

β-Caryophyllene, A Natural Dietary CB2 Receptor Selective Cannabinoid can be a Candidate to Target the Trinity of Infection, Immunity, and Inflammation in COVID-19

Coronavirus disease (COVID-19), caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an ongoing pandemic and presents a public health emergency. It has affected millions of people and continues to affect more, despite tremendous social preventive measures. Identifying candidate drugs for the prevention and treatment of COVID-19 is crucial. The pathogenesis and the complications with advanced infection mainly involve an immune-inflammatory cascade. Therefore, therapeutic strategy relies on suppressing infectivity and inflammation, along with immune modulation. One of the most promising therapeutic targets for the modulation of immune-inflammatory responses is the endocannabinoid system, particularly the activation of cannabinoid type 2 receptors (CB2R), a G-protein coupled receptor which mediates the anti-inflammatory properties by modulating numerous signaling pathways. To pharmacologically activate the CB2 receptors, a naturally occurring cannabinoid ligand, beta-caryophyllene (BCP), received attention due to its potent anti-inflammatory, antiviral, and immunomodulatory properties. BCP is recognized as a full selective functional agonist on CB2 receptors and produces therapeutic effects by activating CB2 and the nuclear receptors, peroxisome proliferator-activated receptors (PPARs). BCP is regarded as the first dietary cannabinoid with abundant presence across cannabis and non-cannabis plants, including spices and other edible plants. BCP showed tissue protective properties and favorably modulates numerous signaling pathways and inhibits inflammatory mediators, including cytokines, chemokines, adhesion molecules, prostanoids, and eicosanoids. Based on its pharmacological properties, molecular mechanisms, and the therapeutic potential of BCP as an immunomodulator, anti-inflammatory, organ-protective, and antiviral, we hypothesize that BCP could be a promising therapeutic and/or preventive candidate to target the triad of infection, immunity, and inflammation in COVID-19. In line with numerous studies that proposed the potential of cannabinoids in COVID-19, BCP may be a novel candidate compound for pharmaceutical and nutraceutical development due to its unique functional receptor selectivity, wide availability and accessibility, dietary bioavailability, nonpsychoactivity, and negligible toxicity along with druggable properties, including favorable pharmacokinetic and physicochemical properties. Based on reasonable pharmacological mechanisms and therapeutic properties, we speculate that BCP has potential to be investigated against COVID-19 and will inspire further preclinical and clinical studies.