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1.
Viruses ; 14(3)2022 03 05.
Article in English | MEDLINE | ID: covidwho-1732241

ABSTRACT

Profound clinical differences between the first and second waves of COVID-19 were observed in Europe. Nitric oxide (NO) may positively impact patients with Severe Acute Respiratory Syndrome CoronaVirus-2 (SARS-CoV-2) infection. It is mainly generated by inducible nitric oxide synthase (iNOS). We studied serum iNOS levels together with serum interleukin (IL)-6 and IL-10 in patients with SARS-CoV-2 infection in the first wave (n = 35) and second wave (n = 153). In the first wave, serum iNOS, IL-6, IL-10 levels increased significantly, in line with the World Health Organization (WHO) score severity, while in the second wave, iNOS did not change with the severity. The patients of the second wave showed lower levels of iNOS, IL-6, and IL-10, as compared to the corresponding subgroup of the first wave, suggesting a less severe outcome of COVID-19 in these patients. However, in the severe patients of the second wave, iNOS levels were significantly lower in patients treated with steroids or azithromycin before the hospitalization, as compared to the untreated patients. This suggests an impairment of the defense mechanism against the virus and NO-based therapies as a potential therapy in patients with low iNOS levels.


Subject(s)
COVID-19 , Humans , Nitric Oxide/metabolism , Nitric Oxide Synthase Type II , SARS-CoV-2
2.
Am J Physiol Heart Circ Physiol ; 322(2): H319-H327, 2022 02 01.
Article in English | MEDLINE | ID: covidwho-1613119

ABSTRACT

Vascular dysfunction has been reported in adults who have recovered from COVID-19. To date, no studies have investigated the underlying mechanisms of persistent COVID-19-associated vascular dysfunction. Our purpose was to quantify nitric oxide (NO)-mediated vasodilation in healthy adults who have recovered from SARS-CoV-2 infection. We hypothesized that COVID-19-recovered adults would have impaired NO-mediated vasodilation compared with adults who have not had COVID-19. In methods, we performed a cross-sectional study including 10 (5 men/5 women, 24 ± 4 yr) healthy control (HC) adults who were unvaccinated for COVID-19, 11 (4 men/7 women, 25 ± 6 yr) healthy vaccinated (HV) adults, and 12 (5 men/7 women, 22 ± 3 yr) post-COVID-19 (PC, 19 ± 14 wk) adults. COVID-19 symptoms severity (survey) was assessed. A standardized 39°C local heating protocol was used to assess NO-dependent vasodilation via perfusion (intradermal microdialysis) of 15 mM NG-nitro-l-arginine methyl ester during the plateau of the heating response. Red blood cell flux was measured (laser-Doppler flowmetry) and cutaneous vascular conductance (CVC = flux/mmHg) was expressed as a percentage of maximum (28 mM sodium nitroprusside + 43°C). In results, the local heating plateau (HC: 61 ± 20%, HV: 60 ± 19%, PC: 67 ± 19%, P = 0.80) and NO-dependent vasodilation (HC: 77 ± 9%, HV: 71 ± 7%, PC: 70 ± 10%, P = 0.36) were not different among groups. Neither symptom severity (25 ± 12 AU) nor time since diagnosis correlated with the NO-dependent vasodilation (r = 0.46, P = 0.13; r = 0.41, P = 0.19, respectively). In conclusion, healthy adults who have had mild-to-moderate COVID-19 do not have altered NO-mediated cutaneous microvascular function.NEW & NOTEWORTHY Healthy young adults who have had mild-to-moderate COVID-19 do not display alterations in nitric oxide-mediated cutaneous microvascular function. In addition, healthy young adults who have COVID-19 antibodies from the COVID-19 vaccinations do not display alterations in nitric oxide-mediated cutaneous microvascular function.


Subject(s)
COVID-19/physiopathology , Microcirculation/physiology , Skin/blood supply , Vasodilation/physiology , Adult , COVID-19/metabolism , COVID-19/prevention & control , COVID-19 Vaccines/therapeutic use , Case-Control Studies , Enzyme Inhibitors/pharmacology , Female , Humans , Laser-Doppler Flowmetry , Male , Microcirculation/drug effects , NG-Nitroarginine Methyl Ester/pharmacology , Nitric Oxide/metabolism , SARS-CoV-2 , Severity of Illness Index , Vasodilation/drug effects , Young Adult
3.
Int J Mol Sci ; 22(24)2021 Dec 13.
Article in English | MEDLINE | ID: covidwho-1599176

ABSTRACT

To determine whether mitigating the harmful effects of circulating microvesicle-associated inducible nitric oxide (MV-A iNOS) in vivo increases the survival of challenged mice in three different mouse models of sepsis, the ability of anti-MV-A iNOS monoclonal antibodies (mAbs) to rescue challenged mice was assessed using three different mouse models of sepsis. The vivarium of a research laboratory Balb/c mice were challenged with an LD80 dose of either lipopolysaccharide (LPS/endotoxin), TNFα, or MV-A iNOS and then treated at various times after the challenge with saline as control or with an anti-MV-A iNOS mAb as a potential immunotherapeutic to treat sepsis. Each group of mice was checked daily for survivors, and Kaplan-Meier survival curves were constructed. Five different murine anti-MV-A iNOS mAbs from our panel of 24 murine anti-MV-A iNOS mAbs were found to rescue some of the challenged mice. All five murine mAbs were used to genetically engineer humanized anti-MV-A iNOS mAbs by inserting the murine complementarity-determining regions (CDRs) into a human IgG1,kappa scaffold and expressing the humanized mAbs in CHO cells. Three humanized anti-MV-A iNOS mAbs were effective at rescuing mice from sepsis in three different animal models of sepsis. The effectiveness of the treatment was both time- and dose-dependent. Humanized anti-MV-A iNOS rHJ mAb could rescue up to 80% of the challenged animals if administered early and at a high dose. Our conclusions are that MV-A iNOS is a novel therapeutic target to treat sepsis; anti-MV-A iNOS mAbs can mitigate the harmful effects of MV-A iNOS; the neutralizing mAb's efficacy is both time- and dose-dependent; and a specifically targeted immunotherapeutic for MV-A iNOS could potentially save tens of thousands of lives annually and could result in improved antibiotic stewardship.


Subject(s)
Cell-Derived Microparticles/metabolism , Nitric Oxide Synthase Type II/metabolism , Sepsis/therapy , Animals , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/therapeutic use , Antibodies, Monoclonal, Humanized/immunology , Antibodies, Monoclonal, Humanized/pharmacology , Cell-Derived Microparticles/immunology , Disease Models, Animal , Humans , Lipopolysaccharides/pharmacology , Mice , Mice, Inbred BALB C , Nitric Oxide/metabolism , Nitric Oxide Synthase Type II/antagonists & inhibitors , Nitric Oxide Synthase Type II/immunology , Tumor Necrosis Factor-alpha/pharmacology
4.
Med Sci (Basel) ; 10(1)2021 12 23.
Article in English | MEDLINE | ID: covidwho-1580579

ABSTRACT

Coronavirus disease 2019 (COVID-19) is a contagious respiratory and vascular disease that continues to spread among people around the world, mutating into new strains with increased transmission rates, such as the delta variant. The scientific community is struggling to discover the link between negative COVID-19 outcomes in patients with preexisting conditions, as well as identify the cause of the negative clinical patient outcomes (patients who need medical attention, including hospitalization) in what seems like a widespread range of COVID-19 symptoms that manifest atypically to any preexisting respiratory tract infectious diseases known so far. Having successfully developed a nutritional formulation intervention based on nitrate, a nitric oxide precursor, the authors hypothesis is that both the comorbidities associated with negative clinical patient outcomes and symptoms associated with COVID-19 sickness are linked to the depletion of a simple molecule: nitric oxide.


Subject(s)
COVID-19/metabolism , COVID-19/physiopathology , Nitric Oxide/metabolism , SARS-CoV-2/pathogenicity , COVID-19/pathology , Humans , Severity of Illness Index
6.
Int J Mol Sci ; 22(22)2021 Nov 10.
Article in English | MEDLINE | ID: covidwho-1512385

ABSTRACT

Nitric oxide (NO) is a key molecule in cardiovascular homeostasis and its abnormal delivery is highly associated with the occurrence and development of cardiovascular disease (CVD). The assessment and manipulation of NO delivery is crucial to the diagnosis and therapy of CVD, such as endothelial dysfunction, atherosclerotic progression, pulmonary hypertension, and cardiovascular manifestations of coronavirus (COVID-19). However, due to the low concentration and fast reaction characteristics of NO in the cardiovascular system, clinical applications centered on NO delivery are challenging. In this tutorial review, we first summarized the methods to estimate the in vivo NO delivery process, based on computational modeling and flow-mediated dilation, to assess endothelial function and vulnerability of atherosclerotic plaque. Then, emerging bioimaging technologies that have the potential to experimentally measure arterial NO concentration were discussed, including Raman spectroscopy and electrochemical sensors. In addition to diagnostic methods, therapies aimed at controlling NO delivery to regulate CVD were reviewed, including the NO release platform to treat endothelial dysfunction and atherosclerosis and inhaled NO therapy to treat pulmonary hypertension and COVID-19. Two potential methods to improve the effectiveness of existing NO therapy were also discussed, including the combination of NO release platform and computational modeling, and stem cell therapy, which currently remains at the laboratory stage but has clinical potential for the treatment of CVD.


Subject(s)
Cardiovascular Diseases/diagnosis , Cardiovascular System/metabolism , Nitric Oxide/metabolism , Administration, Inhalation , Animals , Arteries/metabolism , COVID-19/drug therapy , COVID-19/virology , Cardiovascular Diseases/drug therapy , Humans , Nitric Oxide/therapeutic use , Optical Imaging , SARS-CoV-2/isolation & purification
7.
Nutrients ; 13(11)2021 Nov 05.
Article in English | MEDLINE | ID: covidwho-1502476

ABSTRACT

l-Arginine is involved in many different biological processes and recent reports indicate that it could also play a crucial role in the coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Herein, we present an updated systematic overview of the current evidence on the functional contribution of L-Arginine in COVID-19, describing its actions on endothelial cells and the immune system and discussing its potential as a therapeutic tool, emerged from recent clinical experimentations.


Subject(s)
Arginine/metabolism , COVID-19/metabolism , Endothelial Cells/metabolism , Immune System/metabolism , SARS-CoV-2/pathogenicity , Animals , Arginine/therapeutic use , COVID-19/drug therapy , COVID-19/immunology , COVID-19/virology , Endothelial Cells/drug effects , Endothelial Cells/immunology , Endothelial Cells/virology , Host-Pathogen Interactions , Humans , Immune System/drug effects , Immune System/immunology , Immune System/virology , Nitric Oxide/metabolism , SARS-CoV-2/immunology
8.
PLoS One ; 16(10): e0257644, 2021.
Article in English | MEDLINE | ID: covidwho-1496499

ABSTRACT

BACKGROUND: COVID-19 may present with a variety of clinical syndromes, however, the upper airway and the lower respiratory tract are the principle sites of infection. Previous work on respiratory viral infections demonstrated that airway inflammation results in the release of volatile organic compounds as well as nitric oxide. The detection of these gases from patients' exhaled breath offers a novel potential diagnostic target for COVID-19 that would offer real-time screening of patients for COVID-19 infection. METHODS AND FINDINGS: We present here a breath tester utilizing a catalytically active material, which allows for the temporal manifestation of the gaseous biomarkers' interactions with the sensor, thus giving a distinct breath print of the disease. A total of 46 Intensive Care Unit (ICU) patients on mechanical ventilation participated in the study, 23 with active COVID-19 respiratory infection and 23 non-COVID-19 controls. Exhaled breath bags were collected on ICU days 1, 3, 7, and 10 or until liberation from mechanical ventilation. The breathalyzer detected high exhaled nitric oxide (NO) concentration with a distinctive pattern for patients with active COVID-19 pneumonia. The COVID-19 "breath print" has the pattern of the small Greek letter omega (). The "breath print" identified patients with COVID-19 pneumonia with 88% accuracy upon their admission to the ICU. Furthermore, the sensitivity index of the breath print (which scales with the concentration of the key biomarker ammonia) appears to correlate with duration of COVID-19 infection. CONCLUSIONS: The implication of this breath tester technology for the rapid screening for COVID-19 and potentially detection of other infectious diseases in the future.


Subject(s)
COVID-19/diagnosis , COVID-19/metabolism , Nitric Oxide/analysis , Aged , Biomarkers , Breath Tests/methods , Critical Illness , Female , Humans , Male , Middle Aged , Nitric Oxide/metabolism , Respiratory System/metabolism , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Sensitivity and Specificity , Volatile Organic Compounds/analysis
9.
Mol Neurobiol ; 59(1): 445-458, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1491383

ABSTRACT

In addition to respiratory complications produced by SARS-CoV-2, accumulating evidence suggests that some neurological symptoms are associated with the disease caused by this coronavirus. In this study, we investigated the effects of the SARS-CoV-2 spike protein S1 stimulation on neuroinflammation in BV-2 microglia. Analyses of culture supernatants revealed an increase in the production of TNF-α, IL-6, IL-1ß and iNOS/NO. S1 also increased protein levels of phospho-p65 and phospho-IκBα, as well as enhanced DNA binding and transcriptional activity of NF-κB. These effects of the protein were blocked in the presence of BAY11-7082 (1 µM). Exposure of S1 to BV-2 microglia also increased the protein levels of NLRP3 inflammasome and enhanced caspase-1 activity. Increased protein levels of p38 MAPK was observed in BV-2 microglia stimulated with the spike protein S1 (100 ng/ml), an action that was reduced in the presence of SKF 86,002 (1 µM). Results of immunofluorescence microscopy showed an increase in TLR4 protein expression in S1-stimulated BV-2 microglia. Furthermore, pharmacological inhibition with TAK 242 (1 µM) and transfection with TLR4 small interfering RNA resulted in significant reduction in TNF-α and IL-6 production in S1-stimulated BV-2 microglia. These results have provided the first evidence demonstrating S1-induced neuroinflammation in BV-2 microglia. We propose that induction of neuroinflammation by this protein in the microglia is mediated through activation of NF-κB and p38 MAPK, possibly as a result of TLR4 activation. These results contribute to our understanding of some of the mechanisms involved in CNS pathologies of SARS-CoV-2.


Subject(s)
Microglia/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Animals , Caspase 1/metabolism , Cell Line , Furans/pharmacology , Indenes/pharmacology , Inflammasomes/metabolism , Interleukin-1beta/genetics , Interleukin-6/metabolism , Mice , Microglia/pathology , NF-kappa B/metabolism , Nitric Oxide/metabolism , Nitric Oxide Synthase Type II/metabolism , Nitriles/pharmacology , RNA, Small Interfering , Recombinant Proteins/metabolism , Sulfonamides/pharmacology , Sulfones/pharmacology , Toll-Like Receptor 4/metabolism , Tumor Necrosis Factor-alpha/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism
10.
Int J Mol Sci ; 22(20)2021 Oct 16.
Article in English | MEDLINE | ID: covidwho-1470892

ABSTRACT

BACKGROUND: Atherosclerotic cardiovascular diseases are characterized by a dysregulated inflammatory and thrombotic state, leading to devastating complications with increased morbidity and mortality rates. SUMMARY: In this review article, we present the available evidence regarding the impact of inflammation on platelet activation in atherosclerosis. Key messages: In the context of a dysfunctional vascular endothelium, structural alterations by means of endothelial glycocalyx thinning or functional modifications through impaired NO bioavailability and increased levels of von Willebrand factor result in platelet activation. Moreover, neutrophil-derived mediators, as well as neutrophil extracellular traps formation, have been implicated in the process of platelet activation and platelet-leukocyte aggregation. The role of pro-inflammatory cytokines is also critical since their receptors are also situated in platelets while TNF-α has also been found to induce inflammatory, metabolic, and bone marrow changes. Additionally, important progress has been made towards novel concepts of the interaction between inflammation and platelet activation, such as the toll-like receptors, myeloperoxidase, and platelet factor-4. The accumulating evidence is especially important in the era of the coronavirus disease-19 pandemic, characterized by an excessive inflammatory burden leading to thrombotic complications, partially mediated by platelet activation. Lastly, recent advances in anti-inflammatory therapies point towards an anti-thrombotic effect secondary to diminished platelet activation.


Subject(s)
Atherosclerosis/pathology , COVID-19/pathology , Inflammation Mediators/metabolism , Atherosclerosis/metabolism , COVID-19/virology , Endothelium, Vascular/metabolism , Humans , Neutrophils/metabolism , Nitric Oxide/metabolism , Platelet Activation , SARS-CoV-2/isolation & purification , von Willebrand Factor/metabolism
11.
Respir Res ; 22(1): 237, 2021 Aug 26.
Article in English | MEDLINE | ID: covidwho-1371969

ABSTRACT

Follow-up studies of COVID-19 patients have found lung function impairment up to six months after initial infection, but small airway function has not previously been studied. Patients (n = 20) hospitalised for a severe SARS-CoV-2 infection underwent spirometry, impulse oscillometry, and multiple measurements of alveolar nitric oxide three to six months after acute infection. None of the patients had small airway obstruction, nor increased nitric oxide concentration in the alveolar level. None of the patients had a reduced FEV1/FVC or significant bronchodilator responses in IOS or spirometry. In conclusion, we found no evidence of inflammation or dysfunction in the small airways.


Subject(s)
COVID-19/complications , COVID-19/physiopathology , Respiratory Tract Diseases/physiopathology , Adult , Aged , Female , Finland , Follow-Up Studies , Forced Expiratory Volume , Humans , Length of Stay , Male , Middle Aged , Nitric Oxide/metabolism , Pulmonary Alveoli/metabolism , Respiratory Function Tests , Respiratory Tract Diseases/etiology , Spirometry , Survivors , Vital Capacity
12.
Nitric Oxide ; 115: 55-61, 2021 10 01.
Article in English | MEDLINE | ID: covidwho-1340778

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide and has seriously threatened public health by causing significant morbidity and mortality. Patients with coronavirus disease (COVID-19) with preexisting endothelial dysfunction caused by aging, diabetes, hypertension, and obesity are at high risk for life-threatening thromboembolic complications. This suggests a possibility that reduced endothelial nitric oxide (NO) production and NO bioavailability could be a common underlying pathology for the progression of COVID-19. Increasingly, evidence from experimental and clinical studies of SARS-CoV-2 infection shows that NO inhibits the pathogenesis of COVID-19, including virus entry into host cells, viral replication, host immune response, and subsequent thromboembolic complications. Restoring NO bioavailability may have the potential to be a preventive or early-treatment option for COVID-19. This review aims to provide in-depth discussion of NO bioavailability to prevent SARS-CoV-2 infection, particularly by focusing on lifestyle factors such as nitrate-rich diets, physical exercise, and nasal breathing, which could be easily performed on a daily basis to boost NO bioavailability.


Subject(s)
COVID-19/prevention & control , Life Style , Nitric Oxide/metabolism , COVID-19/metabolism , Humans
13.
Int J Mol Sci ; 22(14)2021 Jul 15.
Article in English | MEDLINE | ID: covidwho-1323264

ABSTRACT

The human paranasal sinuses are the major source of intrinsic nitric oxide (NO) production in the human airway. NO plays several roles in the maintenance of physiological homeostasis and the regulation of airway inflammation through the expression of three NO synthase (NOS) isoforms. Measuring NO levels can contribute to the diagnosis and assessment of allergic rhinitis (AR) and chronic rhinosinusitis (CRS). In symptomatic AR patients, pro-inflammatory cytokines upregulate the expression of inducible NOS (iNOS) in the inferior turbinate. Excessive amounts of NO cause oxidative damage to cellular components, leading to the deposition of cytotoxic substances. CRS phenotype and endotype classifications have provided insights into modern treatment strategies. Analyses of the production of sinus NO and its metabolites revealed pathobiological diversity that can be exploited for useful biomarkers. Measuring nasal NO based on different NOS activities is a potent tool for specific interventions targeting molecular pathways underlying CRS endotype-specific inflammation. We provide a comprehensive review of the functional diversity of NOS isoforms in the human sinonasal system in relation to these two major nasal disorders' pathologies. The regulatory mechanisms of NOS expression associated with the substrate bioavailability indicate the involvement of both type 1 and type 2 immune responses.


Subject(s)
Nasal Mucosa/enzymology , Nitric Oxide Synthase/metabolism , Nitric Oxide/metabolism , Paranasal Sinuses/enzymology , Rhinitis, Allergic/physiopathology , Sinusitis/physiopathology , Animals , Chronic Disease , Humans , Isoenzymes , Rhinitis, Allergic/metabolism , Sinusitis/metabolism
14.
BMC Complement Med Ther ; 21(1): 192, 2021 Jul 05.
Article in English | MEDLINE | ID: covidwho-1317123

ABSTRACT

BACKGROUND: Lippia javanica (lemon bush) is commonly used in the treatment of respiratory ailments, including asthma in southern African countries but there is no scientific evidence to support this claim. This study investigated the anti-inflammatory, antioxidant and anti-asthmatic effects of L. javanica using a rat model of asthma. METHODS: A 5% w/v L. javanica tea infusion was prepared and characterised by liquid chromatography-mass spectrometer (LC-MS). Animals were intraperitoneally sensitized with ovalbumin (OVA) and subsequently challenged intranasal with OVA on day 15 except the control group. Animals were grouped (n = 5/group) for treatment: unsensitised control, sensitised control, sensitised + prednisolone and sensitised + L. javanica at 50 mg/kg/day and 100 mg/kg/day - equivalent to 1 and 2 cups of tea per day, respectively. After 2 weeks of treatment, bronchoalveolar lavage fluid (BALF) was collected for total and differential white blood cell (WBC) count. Nitric oxide (NO), lipid peroxidation and antioxidants were also assessed in BALF. Ovalbumin specific IgE antibody and inflammatory cytokines: IL-4, IL-5, IL-13 and TNF-alpha were measured in serum. Lung and muscle tissues were histological examined. RESULTS: L. javanica was rich in phenolic compounds. OVA sensitisation resulted in development of allergic asthma in rats. L. javanica treatment resulted in a reduction in total WBC count as well as eosinophils, lymphocytes and neutrophils in BALF. L. javanica inhibited Th2-mediated immune response, which was evident by a decrease in serum IgE and inflammatory cytokines: IL-4, IL-5, IL-13 and TNF-α. L. javanica treatment also reduced malondialdehyde (MDA) and NO, and increased superoxide dismutase, glutathione and total antioxidant capacity. Histology showed significant attenuation of lung infiltration of inflammatory cells, alveolar thickening, and bronchiole smooth muscle thickening. CONCLUSION: L. javanica suppressed allergic airway inflammation by reducing Th2-mediated immune response and oxidative stress in OVA-sensitized rats which may be attributed to the presence of phenolic compound in the plant. This finding validates the traditional use of L. javanica in the treatment of respiratory disorders.


Subject(s)
Asthma/drug therapy , Lippia , Teas, Herbal , Animals , Antioxidants/metabolism , Asthma/pathology , Bronchoalveolar Lavage Fluid/cytology , Cytokines/blood , Disease Models, Animal , Eosinophils/metabolism , Glutathione/metabolism , Immunoglobulin E/blood , Leukocyte Count , Lung/pathology , Lymphocytes/metabolism , Malondialdehyde/metabolism , Neutrophils/metabolism , Nitric Oxide/metabolism , Oxidative Stress/drug effects , Rats, Wistar , Superoxide Dismutase/metabolism , Th2 Cells/drug effects
15.
J Inorg Biochem ; 223: 111546, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1313251

ABSTRACT

Recent studies have shown a correlation between COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and the distinct, exaggerated immune response titled "cytokine storm". This immune response leads to excessive production and accumulation of reactive oxygen species (ROS) that cause clinical signs characteristic of COVID-19 such as decreased oxygen saturation, alteration of hemoglobin properties, decreased nitric oxide (NO) bioavailability, vasoconstriction, elevated cytokines, cardiac and/or renal injury, enhanced D-dimer, leukocytosis, and an increased neutrophil to lymphocyte ratio. Particularly, neutrophil myeloperoxidase (MPO) is thought to be especially abundant and, as a result, contributes substantially to oxidative stress and the pathophysiology of COVID-19. Conversely, melatonin, a potent MPO inhibitor, has been noted for its anti-inflammatory, anti-oxidative, anti-apoptotic, and neuroprotective actions. Melatonin has been proposed as a safe therapeutic agent for COVID-19 recently, having been given with a US Food and Drug Administration emergency authorized cocktail, REGEN-COV2, for management of COVID-19 progression. This review distinctly highlights both how the destructive interactions of HOCl with tetrapyrrole rings may contribute to oxygen deficiency and hypoxia, vitamin B12 deficiency, NO deficiency, increased oxidative stress, and sleep disturbance, as well as how melatonin acts to prevent these events, thereby improving COVID-19 prognosis.


Subject(s)
Antioxidants/pharmacology , COVID-19/drug therapy , Melatonin/pharmacology , Reactive Oxygen Species/metabolism , Anti-Inflammatory Agents/pharmacology , Apoptosis/drug effects , COVID-19/immunology , COVID-19/metabolism , Cytokine Release Syndrome/immunology , Cytokines/metabolism , Hemeproteins/metabolism , Humans , Hypochlorous Acid/metabolism , Nitric Oxide/metabolism , Oxidation-Reduction , Oxidative Stress/drug effects , Peroxidase/metabolism , SARS-CoV-2 , Sleep/drug effects , Vitamin B Deficiency/metabolism
16.
Int J Mol Sci ; 22(13)2021 Jun 26.
Article in English | MEDLINE | ID: covidwho-1304664

ABSTRACT

Hepatitis C virus (HCV) is one of the main triggers of chronic liver disease. Despite tremendous progress in the HCV field, there is still no vaccine against this virus. Potential vaccines can be based on its recombinant proteins. To increase the humoral and, especially, cellular immune response to them, more effective adjuvants are needed. Here, we evaluated a panel of compounds as potential adjuvants using the HCV NS5B protein as an immunogen. These compounds included inhibitors of polyamine biosynthesis and urea cycle, the mTOR pathway, antioxidants, and cellular receptors. A pronounced stimulation of cell proliferation and interferon-γ (IFN-γ) secretion in response to concanavalin A was shown for antioxidant N-acetylcysteine (NAC), polyamine biosynthesis inhibitor 2-difluoromethylornithine (DFMO), and TLR9 agonist CpG ODN 1826 (CpG). Their usage during the immunization of mice with the recombinant NS5B protein significantly increased antibody titers, enhanced lymphocyte proliferation and IFN-γ production. NAC and CpG decreased relative Treg numbers; CpG increased the number of myeloid-derived suppressor cells (MDSCs), whereas neither NAC nor DFMO affected MDSC counts. NAC and DFMO suppressed NO and interleukin 10 (IL-10) production by splenocytes, while DFMO increased the levels of IL-12. This is the first evidence of immunomodulatory activity of NAC and DFMO during prophylactic immunization against infectious diseases.


Subject(s)
Acetylcysteine/pharmacology , Adjuvants, Immunologic/pharmacology , Eflornithine/pharmacology , Hepatitis C/immunology , Immunity, Active/drug effects , Viral Nonstructural Proteins/immunology , Animals , Cell Proliferation , Cells, Cultured , Female , Immunogenicity, Vaccine/drug effects , Interferon-gamma/metabolism , Interleukin-10/metabolism , Interleukin-12/metabolism , Mice , Mice, Inbred DBA , Myeloid-Derived Suppressor Cells/drug effects , Myeloid-Derived Suppressor Cells/immunology , Nitric Oxide/metabolism , Oligodeoxyribonucleotides/pharmacology , T-Lymphocytes, Regulatory/drug effects , T-Lymphocytes, Regulatory/immunology , Viral Hepatitis Vaccines/immunology
17.
BMC Complement Med Ther ; 21(1): 192, 2021 Jul 05.
Article in English | MEDLINE | ID: covidwho-1296592

ABSTRACT

BACKGROUND: Lippia javanica (lemon bush) is commonly used in the treatment of respiratory ailments, including asthma in southern African countries but there is no scientific evidence to support this claim. This study investigated the anti-inflammatory, antioxidant and anti-asthmatic effects of L. javanica using a rat model of asthma. METHODS: A 5% w/v L. javanica tea infusion was prepared and characterised by liquid chromatography-mass spectrometer (LC-MS). Animals were intraperitoneally sensitized with ovalbumin (OVA) and subsequently challenged intranasal with OVA on day 15 except the control group. Animals were grouped (n = 5/group) for treatment: unsensitised control, sensitised control, sensitised + prednisolone and sensitised + L. javanica at 50 mg/kg/day and 100 mg/kg/day - equivalent to 1 and 2 cups of tea per day, respectively. After 2 weeks of treatment, bronchoalveolar lavage fluid (BALF) was collected for total and differential white blood cell (WBC) count. Nitric oxide (NO), lipid peroxidation and antioxidants were also assessed in BALF. Ovalbumin specific IgE antibody and inflammatory cytokines: IL-4, IL-5, IL-13 and TNF-alpha were measured in serum. Lung and muscle tissues were histological examined. RESULTS: L. javanica was rich in phenolic compounds. OVA sensitisation resulted in development of allergic asthma in rats. L. javanica treatment resulted in a reduction in total WBC count as well as eosinophils, lymphocytes and neutrophils in BALF. L. javanica inhibited Th2-mediated immune response, which was evident by a decrease in serum IgE and inflammatory cytokines: IL-4, IL-5, IL-13 and TNF-α. L. javanica treatment also reduced malondialdehyde (MDA) and NO, and increased superoxide dismutase, glutathione and total antioxidant capacity. Histology showed significant attenuation of lung infiltration of inflammatory cells, alveolar thickening, and bronchiole smooth muscle thickening. CONCLUSION: L. javanica suppressed allergic airway inflammation by reducing Th2-mediated immune response and oxidative stress in OVA-sensitized rats which may be attributed to the presence of phenolic compound in the plant. This finding validates the traditional use of L. javanica in the treatment of respiratory disorders.


Subject(s)
Asthma/drug therapy , Lippia , Teas, Herbal , Animals , Antioxidants/metabolism , Asthma/pathology , Bronchoalveolar Lavage Fluid/cytology , Cytokines/blood , Disease Models, Animal , Eosinophils/metabolism , Glutathione/metabolism , Immunoglobulin E/blood , Leukocyte Count , Lung/pathology , Lymphocytes/metabolism , Malondialdehyde/metabolism , Neutrophils/metabolism , Nitric Oxide/metabolism , Oxidative Stress/drug effects , Rats, Wistar , Superoxide Dismutase/metabolism , Th2 Cells/drug effects
18.
Int J Mol Sci ; 22(12)2021 Jun 13.
Article in English | MEDLINE | ID: covidwho-1273455

ABSTRACT

Inflammation is an old concept that has started to be considered as an important factor in infection and chronic diseases. The role of leukocytes, the plasmatic components, then of the mediators such as prostaglandins, cytokines, and, in recent decades, of the endothelium has completed the concept of the inflammation process. The function of the endothelium appeared to be crucial as a regulator or the initiator of the inflammatory process. Culture of human endothelial cells and experimental systems made it possible to define the molecular basis of inflammation in vascular diseases, in diabetes mellitus, atherosclerosis, vasculitis and thromboembolic complications. Advanced glycation end product receptor (RAGE), present on endothelial cells (ECs) and monocytes, participates in the activation of these cells in inflammatory conditions. Inflammasome is a cytosolic multiprotein that controls the response to diverse microorganisms. It is positively regulated by stimulator of interferon response CGAMP interactor-1 (STING1). Angiogenesis and thrombotic events are dysregulated during inflammation. ECs appear to be a protector, but also a possible initiator of thrombosis.


Subject(s)
Atherosclerosis/pathology , Endothelium, Vascular/metabolism , Thrombosis/pathology , Atherosclerosis/metabolism , Endothelium, Vascular/cytology , Humans , Inflammasomes/metabolism , Membrane Proteins/metabolism , Neovascularization, Physiologic , Nitric Oxide/metabolism , Receptor for Advanced Glycation End Products/metabolism , Thrombosis/metabolism
20.
Microvasc Res ; 137: 104188, 2021 09.
Article in English | MEDLINE | ID: covidwho-1237818

ABSTRACT

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been led to a pandemic emergency. So far, different pathological pathways for SARS-CoV-2 infection have been introduced in which the excess release of pro-inflammatory cytokines (such as interleukin 1 ß [IL-1ß], IL-6, and tumor necrosis factor α [TNFα]) has earned most of the attentions. However, recent studies have identified new pathways with at least the same level of importance as cytokine storm in which endothelial cell (EC) dysfunction is one of them. In COVID-19, two main pathologic phenomena have been seen as a result of EC dysfunction: hyper-coagulation state and pathologic angiogenesis. The EC dysfunction-induced hypercoagulation state seems to be caused by alteration in the levels of different factors such as plasminogen activator inhibitor 1 (PAI-1), von Willebrand factor (vWF) antigen, soluble thrombomodulin, and tissue factor pathway inhibitor (TFPI). As data have shown, these thromboembolic events are associated with severity of disease severity or even death in COVID-19 patients. Other than thromboembolic events, pathologic angiogenesis is among the recent findings. Furthermore, over-expression/higher levels of different proangiogenic factors such as vascular endothelial growth factor (VEGF), hypoxia-inducible factor 1 α (HIF-1α), IL-6, TNF receptor super family 1A and 12, and angiotensin-converting enzyme 2 (ACE2) have been found in the lung biopsies/sera of both survived and non-survived COVID-19 patients. Also, there are some hypotheses regarding the role of nitric oxide in EC dysfunction and acute respiratory distress syndrome (ARDS) in SARS-CoV-2 infection. It has been demonstrated that different pathways involved in inflammation are generally common with EC dysfunction and angiogenesis. Altogether, considering the common possible upstream pathways in cytokine storm, pathologic angiogenesis, and EC dysfunction, it seems that targeting these molecules (such as nuclear factor κB) could be more effective in the management of patients with COVID-19.


Subject(s)
COVID-19/blood , COVID-19/physiopathology , Endothelial Cells/metabolism , Neovascularization, Pathologic , Angiotensin-Converting Enzyme 2/metabolism , Biomarkers/metabolism , Blood Coagulation , Cytokine Release Syndrome , Humans , Inflammation , Interleukin-1beta/metabolism , Interleukin-6/metabolism , Lipoproteins/metabolism , Nitric Oxide/metabolism , Plasminogen Activator Inhibitor 1/metabolism , SARS-CoV-2 , Tumor Necrosis Factor-alpha/metabolism , von Willebrand Factor/metabolism
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