High dose N-acetyl cysteine improves inflammatory response and outcome in patients with COPD exacerbations

Molecular Mechanisms of N-Acetylcysteine in RSV Infections and Air Pollution-Induced Alterations: A Scoping Review

N-acetylcysteine (NAC) is a mucolytic agent with antioxidant and anti-inflammatory properties. The respiratory syncytial virus (RSV) is one of the most important etiological factors of lower respiratory tract infections, and exposure to air pollution appears to be additionally associated with higher RSV incidence and disease severity. We aimed to systematically review the existing literature to determine which molecular mechanisms mediate the effects of NAC in an RSV infection and air pollution, and to identify the knowledge gaps in this field. A search for original studies was carried out in three databases and a calibrated extraction grid was used to extract data on the NAC treatment (dose, timing), the air pollutant type, and the most significant mechanisms. We identified only 28 studies conducted in human cellular models (n = 18), animal models (n = 7), and mixed models (n = 3). NAC treatment improves the barrier function of the epithelium damaged by RSV and air pollution, and reduces the epithelial permeability, protecting against viral entry. NAC may also block RSV-activated phosphorylation of the epidermal growth factor receptor (EGFR), which promotes endocytosis and facilitates cell entry. EGFR also enhances the release of a mucin gene, MUC5AC, which increases mucus viscosity and causes goblet cell metaplasia; the effects are abrogated by NAC. NAC blocks virus release from the infected cells, attenuates the cigarette smoke-induced shift from necrosis to apoptosis, and reverses the block in IFN-γ-induced antiviral gene expression caused by the inhibited Stat1 phosphorylation. Increased synthesis of pro-inflammatory cytokines and chemokines is induced by both RSV and air pollutants and is mediated by the nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways that are activated in response to oxidative stress. MCP-1 (monocyte chemoattractant protein-1) and RANTES (regulated upon activation, expressed and secreted by normal T cells) partially mediate airway hyperresponsiveness (AHR), and therapeutic (but not preventive) NAC administration reduces the inflammatory response and has been shown to reduce ozone-induced AHR. Oxidative stress-induced DNA damage and cellular senescence, observed during RSV infection and exposure to air pollution, can be partially reversed by NAC administration, while data on the emphysema formation are disputed. The review identified potential common molecular mechanisms of interest that are affected by NAC and may alleviate both the RSV infection and the effects of air pollution. Data are limited and gaps in knowledge include the optimal timing or dosage of NAC administration, therefore future studies should clarify these uncertainties and verify its practical use.

Influence of dose and exposition time in the effectiveness of N-Acetyl-l-cysteine treatment in A549 human epithelial cells

N-Acetyl-l-cysteine (NAC) acts as a precursor of the tripeptide glutathione (GSH), one of the principal cell mechanisms for reactive oxygen species (ROS) detoxification. Chronic obstructive pulmonary disease (COPD) is associated with enhanced inflammatory response and oxidative stress and NAC has been used to suppress various pathogenic processes in this disease. Studies show that the effects of NAC are dose-dependent, and it appears that the efficient doses in vitro are usually higher than the achieved in vivo plasma concentrations. However, to date, the inconsistencies between the in vitro NAC antioxidant and anti-inflammatory in vitro effects, by reproducing the in vivo NAC plasma concentrations as well as high NAC concentrations. To do so, A549 were transfected with polyinosinic-polycytidylic acid (Poly (I:C)) and treated with NAC at different treatment periods. Oxidative stress, release of proinflammatory mediators and NFkB activation were analyzed. Results suggest that NAC at low doses in chronic administration has sustained antioxidant and anti-inflammatory effects, while acute treatment with high dose NAC exerts a strong antioxidant and anti-inflammatory response.

Mucolytics for acute exacerbations of chronic obstructive pulmonary disease: a meta-analysis

This meta-analysis explored the safety and effectiveness of mucolytics as an add-on treatment for chronic obstructive pulmonary disease (COPD) exacerbations. Based on a pre-registered protocol and following Cochrane methods, we systematically searched for relevant randomised or quasi-randomised controlled trials (RCTs). We used the Risk of Bias v2 tool for appraising the studies and performed random-effect meta-analyses when appropriate. We assessed certainty of evidence using GRADE. This meta-analysis included 24 RCTs involving 2192 patients with COPD exacerbations, entailing at least some concerns of methodological bias. We demonstrated with moderate certainty that mucolytics increase the rate of treatment success (relative risk 1.37, 95% CI 1.08-1.73, n=383), while they also exert benefits on overall symptom scores (standardised mean difference 0.86, 95% CI 0.63-1.09, n=316), presence of cough at follow-up (relative risk 1.93, 95% CI 1.15-3.23) and ease of expectoration (relative risk 2.94, 95% CI 1.68-5.12). Furthermore, low or very low certainty evidence suggests mucolytics may also reduce future risk of exacerbations and improve health-related quality of life, but do not impact on breathlessness, length of hospital stay, indication for higher level of care or serious adverse events. Overall, mucolytics could be considered for COPD exacerbation management. These findings should be validated in further, rigorous RCTs.

Effects of N-acetyl-l-cysteine on chronic heat stress-induced oxidative stress and inflammation in the ovaries of growing pullets

The aims of this study were to investigate the effects of supplemental N-acetyl-l-cysteine (NAC) on chronic heat stress-induced oxidative stress and inflammation in the ovaries of growing pullets. A total of 120, 12-wk-old, Hy-Line Brown hens were randomly separated into 4 groups with 6 replicates of 5 birds in each group for 21 d. The 4 treatments were as follows: the CON group and CN group were supplemented with basal diet or basal diet with 1 g/kg NAC, respectively; and the HS group and HSN group were heat-stressed groups supplemented with basal diet or basal diet with 1 g/kg NAC, respectively. The results indicated that the ovaries suffered pathological damage due to chronic heat stress and that NAC effectively ameliorated these changes. Compared with the HS group, antioxidant enzyme activities (including SOD, GSH-Px, CAT, and T-AOC) were enhanced, while the MDA contents and the expression levels of HSP70 were decreased in the HSN group. In addition, NAC upregulated the expression levels of HO-1, SOD2, and GST by upregulating the activity of Nrf2 at different time points to mitigate oxidative stress caused by heat exposure. Simultaneously, NAC attenuated chronic heat stress-induced NF-κB pathway activation and decreased the expression levels of the proinflammatory cytokines IL-8, IL-18, TNF-α, IKK-α, and IFN-γ. Cumulatively, our results indicated that NAC could ameliorate chronic heat stress-induced ovarian damage by upregulating the antioxidative capacity and reducing the secretion of proinflammatory cytokines.

Pinocembrin Relieves Mycoplasma pneumoniae Infection‑Induced Pneumonia in Mice Through the Inhibition of Oxidative Stress and Inflammatory Response

Pneumonia is a serious infectious disease with increased morbidity and mortality worldwide. The M. pneumoniae is a major airway pathogen that mainly affects respiratory tract and ultimately leads to the development of pneumonia. The current exploration was aimed to uncover the beneficial properties of pinocembrin against the M. pneumoniae-triggered pneumonia in mice via its anti-inflammatory property. The pneumonia was stimulated to the BALB/c mice via infecting them with M. pneumoniae (100 µl) for 2 days through nasal drops and concomitantly treated with pinocembrin (10 mg/kg) for 3 days. The azithromycin (100 mg/kg) was used as a standard drug. Then the lung weight, nitric oxide, and myeloperoxidase (MPO) activity was assessed. The content of MDA, GSH, and SOD activity was scrutinized using kits. The total cells and DNA amount present in the bronchoalveolar lavage fluid (BALF) was assessed by standard methods. The IL-1, IL-6, IL-8, TNF-α, and TGF contents in the BALF samples and NF-κB level in the lung tissues were assessed using kits. The lung histopathology was assessed microscopically to detect the histological alterations. The 10 mg/kg of pinocembrin treatment substantially decreased the lung weight, nitric oxide (NO) level, and MPO activity. The MDA level was decreased, and GSH content and SOD activity were improved by the pinocembrin treatment. The pinocembrin administered pneumonia animals also demonstrated the decreased total cells, DNA amount, IL-1, IL-6, IL-8, TNF-α, and TGF in the BALF and NF-κB level. The findings of histological studies also witnessed the beneficial role of pinocembrin against M. pneumoniae-infected pneumonia. In conclusion, our findings confirmed that the pinocembrin effectively ameliorated the M. pneumoniae-provoked inflammation and oxidative stress in the pneumonia mice model. Hence, it could be a hopeful therapeutic agent to treat the pneumonia in the future.

ROS/TNF-α Crosstalk Triggers the Expression of IL-8 and MCP-1 in Human Monocytic THP-1 Cells via the NF-κB and ERK1/2 Mediated Signaling

IL-8/MCP-1 act as neutrophil/monocyte chemoattractants, respectively. Oxidative stress emerges as a key player in the pathophysiology of obesity. However, it remains unclear whether the TNF-α/oxidative stress interplay can trigger IL-8/MCP-1 expression and, if so, by which mechanism(s). IL-8/MCP-1 adipose expression was detected in lean, overweight, and obese individuals, 15 each, using immunohistochemistry. To detect the role of reactive oxygen species (ROS)/TNF-α synergy as a chemokine driver, THP-1 cells were stimulated with TNF-α, with/without H₂O₂ or hypoxia. Target gene expression was measured by qRT-PCR, proteins by flow cytometry/confocal microscopy, ROS by DCFH-DA assay, and signaling pathways by immunoblotting. IL-8/MCP-1 adipose expression was significantly higher in obese/overweight. Furthermore, IL-8/MCP-1 mRNA/protein was amplified in monocytic cells following stimulation with TNF-α in the presence of H₂O₂ or hypoxia (p ˂ 0.0001). Synergistic chemokine upregulation was related to the ROS levels, while pre-treatments with NAC suppressed this chemokine elevation (p ≤ 0.01). The ROS/TNF-α crosstalk involved upregulation of CHOP, ERN1, HIF1A, and NF-κB/ERK-1,2 mediated signaling. In conclusion, IL-8/MCP-1 adipose expression is elevated in obesity. Mechanistically, ROS/TNF-α crosstalk may drive expression of these chemokines in monocytic cells by inducing ER stress, HIF1A stabilization, and signaling via NF-κB/ERK-1,2. NAC had inhibitory effect on oxidative stress-driven IL-8/MCP-1 expression, which may have therapeutic significance regarding meta-inflammation.

N-Acetylcysteine as Adjuvant Therapy for COVID-19 - A Perspective on the Current State of the Evidence

The looming severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a long-lasting pandemic of coronavirus disease 2019 (COVID-19) around the globe with substantial morbidity and mortality. N-acetylcysteine, being a nutraceutical precursor of an important antioxidant glutathione, can perform several biological functions in mammals and microbes. It has consequently garnered a growing interest as a potential adjunctive therapy for coronavirus disease. Here, we review evidence concerning the effects of N-acetylcysteine in respiratory viral infections based on currently available in vitro, in vivo, and human clinical investigations. The repurposing of a known drug such as N-acetylcysteine may significantly hasten the deployment of a novel approach for COVID-19. Since the drug candidate has already been translated into the clinic for several decades, its established pharmacological properties and safety and side-effect profiles expedite preclinical and clinical assessment for the treatment of COVID-19. In vitro data have depicted that N-acetylcysteine increases antioxidant capacity, interferes with virus replication, and suppresses expression of pro-inflammatory cytokines in cells infected with influenza viruses or respiratory syncytial virus. Furthermore, findings from in vivo studies have displayed that, by virtue of immune modulation and anti-inflammatory mechanism, N-acetylcysteine reduces the mortality rate in influenza-infected mice animal models. The promising in vitro and in vivo results have prompted the initiation of human subject research for the treatment of COVID-19, including severe pneumonia and acute respiratory distress syndrome. Albeit some evidence of benefits has been observed in clinical outcomes of patients, precision nanoparticle design of N-acetylcysteine may allow for greater therapeutic efficacy.

Protective action of N-acetyl-L-cysteine associated with a polyvalent antivenom on the envenomation induced by Lachesis muta muta (South American bushmaster) in rats

In this study, we examined the potential use of N-acetyl-L-cysteine (NAC) in association with a polyvalent antivenom and as stand-alone therapy to reduce the acute local and systemic effects induced by Lachesis muta muta venom in rats. Male Wistar rats (300-350 g) were exposed to L. m. muta venom (1.5 mg/kg - i.m.) and subsequently treated with anti-Bothrops/Lachesis serum (antivenom:venom ratio 1:3 'v/w' - i.p.) and NAC (150 mg/kg - i.p.) separately or in association; the animals were monitored for 120 min to assess changes in temperature, locomotor activity, local oedema formation and the prevalence of haemorrhaging. After this time, animals were anesthetized in order to collect blood samples through intracardiac puncture and then euthanized for collecting tissue samples; the hematological-biochemical and histopathological analyses were performed through conventional methods. L. m. muta venom produced pronounced local oedema, subcutaneous haemorrhage and myonecrosis, with both antivenom and NAC successfully reducing the extent of the myonecrotic lesion when individually administered; their association also prevented the occurrence of subcutaneous haemorrhage. Venom-induced creatine kinase (CK) release was significantly prevented by NAC alone or in combination with antivenom; NAC alone failed to reduce the release of hepatotoxic (alanine aminotransferase) and nephrotoxic (creatinine) serum biomarkers induced by L. m. muta venom. Venom induced significant increase of leucocytes which was also associated with an increase of neutrophils, eosinophils and monocytes; antivenom and NAC partially reduced these alterations, with NAC alone significantly preventing the increase of eosinophils whereas neither NAC or antivenom prevented the increase in monocytes. Venom did not induce changes in the erythrogram parameters. In the absence of a suitable antivenom, NAC has the potential to reduce a number of local and systemic effects caused by L. m. muta venom.

Mitigation of arsenic driven utero-ovarian malfunction and changes of apoptotic gene expression by dietary NAC

An oral painless dietary therapy is also indispensable in the management of arsenic toxicity despite of its conventional painful therapeutic management. The present study focused on the management of arsenic mediated female reproductive dysfunctions by dietary therapy of N-acetyl cysteine (NAC). Here, sodium arsenite was given at the dose of 10 mg/kg body weight orally for the first 8 day. Day 9 onwards up to day 16 these arsenicated rats were provided with NAC (250 mg/kg body weight) enriched basal diet once daily. Arsenic intoxicated group exhibited a comparable inactivation of antioxidant enzymes superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) due to oxidative stress in reproductive organs along with a simultaneous elevation of lipid peroxidation state and decline in non-protein soluble thiols (NPSH) level in female reproductive organs. Arsenic intoxication also accomplished with the up-regulation of inflammatory markers tumour necrosis factor (TNF α) and nuclear factor κB (NF κB). Pro-apoptotic Bax gene and p53 gene expressions were also raised due to arsenic intoxication while anti-apoptotic Bcl-2 gene expression was suppressed. In fact, arsenication decreased the circulating level of vitamin B12 and folic acid. Dietary NAC supplementation significantly reversed back the activity of antioxidant enzymes in arsenite fed rats towards normalcy and also sustained the normal reproductive cyclicity, utero-ovarian histo-morphology and estradiol receptor α (ER-α) expression in these reproductive organs. Dietary NAC exerted its positive action against arsenic intoxication by up-regulation of Bcl-2 gene expression along with the suppression of pro-apoptotic Bax gene and p53 gene. Thus, dietary NAC also plays anti-apoptotic, anti-inflammatory, and anti-oxidative role against arsenic toxicity. NAC also regulates the components (vitamin B12 and folic acid) of S-adenosylmethionine pool in the way of probable removal of arsenic from the system.

Micronutrients as immunomodulatory tools for COVID-19 management

COVID-19 rapidly turned to a global pandemic posing lethal threats to overwhelming health care capabilities, despite its relatively low mortality rate. The clinical respiratory symptoms include dry cough, fever, anosmia, breathing difficulties, and subsequent respiratory failure. No known cure is available for COVID-19. Apart from the anti-viral strategy, the supports of immune effectors and modulation of immunosuppressive mechanisms is the rationale immunomodulation approach in COVID-19 management. Diet and nutrition are essential for healthy immunity. However, a group of micronutrients plays a dominant role in immunomodulation. The deficiency of most nutrients increases the individual susceptibility to virus infection with a tendency for severe clinical presentation. Despite a shred of evidence, the supplementation of a single nutrient is not promising in the general population. Individuals at high-risk for specific nutrient deficiencies likely benefit from supplementation. The individual dietary and nutritional status assessments are critical for determining the comprehensive actions in COVID-19.

Modulation of bleomycin-induced oxidative stress and pulmonary fibrosis by N-acetylcysteine in rats via AMPK/SIRT1/NF-κβ

The efficacy of bleomycin (BLM) as an antineoplastic drug is limited to the development of dose and time-dependent pulmonary fibrosis. This study was intended to investigate the effect of N-acetylcysteine (NAC) on BLM-induced pulmonary fibrosis in rats. Twenty rats were randomly divided to the following four groups: Group one served as control; group two received BLM (15 mg/kg, intraperitoneal (ip)) for five consecutive days; group three received NAC (200 mg/kg, ip) for five consecutive days; and group four received NAC 1 hour before BLM for 5 days. The expression of connective tissue growth factor (CTGF), platelet-derived growth factor (PDGF), silent information regulator l (SIRT1), AMP-activated protein kinase (AMPK) were determined by qRT-PCR in lung tissues. The changes in transforming growth factor-beta1 (TGF-β1), tumour necrosis factor-α (TNF-α), interleukin-β1 (IL-β1) and nuclear factor kappa-β (NF-κβ) in serum were measured by ELISA. The tissue antioxidant status was determined biochemically. BLM administration caused pulmonary fibrosis as evidenced by increased levels of inflammatory mediators (TGF-β1, TNF-α, IL-β1 and NF-κβ) in serum (P < .05), elevated lipid peroxidation and nitric oxide and depleted endogenous antioxidants in lung tissue (P < .05). The expression levels of SIRT1 and AMPK were significantly decreased (P < .05), while the expression levels of CTGF and PDGF were increased significantly in the BLM group as compared to the control group (P < .05). These alterations were normalized by NAC intervention. NAC markedly attenuated the lung histopathological changes and reduced collagen deposition. These results suggest that NAC exerted an ameliorative effect against BLM-induced oxidative damage and pulmonary fibrosis via SIRT1/ AMPK/ NF-κβ pathways.

Pharmacologic Therapies in Patients With Exacerbation of Chronic Obstructive Pulmonary Disease: A Systematic Review With Meta-analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by frequent exacerbations.

PURPOSE

To evaluate the comparative effectiveness and adverse events (AEs) of pharmacologic interventions for adults with exacerbation of COPD.

DATA SOURCES

English-language searches of several bibliographic sources from database inception to 2 January 2019.

STUDY SELECTION

68 randomized controlled trials that enrolled adults with exacerbation of COPD treated in out- or inpatient settings other than intensive care and compared pharmacologic therapies with placebo, "usual care," or other pharmacologic interventions.

DATA EXTRACTION

Two reviewers independently extracted data and rated study quality and strength of evidence (SOE).

DATA SYNTHESIS

Compared with placebo or management without antibiotics, antibiotics given for 3 to 14 days were associated with increased exacerbation resolution at the end of the intervention (odds ratio [OR], 2.03 [95% CI, 1.47 to 2.80]; moderate SOE) and less treatment failure at the end of the intervention (OR, 0.54 [CI, 0.34 to 0.86]; moderate SOE), independent of severity of exacerbations in out- and inpatients. Compared with placebo in out- and inpatients, systemic corticosteroids given for 9 to 56 days were associated with less treatment failure at the end of the intervention (OR, 0.01 [CI, 0.00 to 0.13]; low SOE) but also with a higher number of total and endocrine-related AEs. Compared with placebo or usual care in inpatients, other pharmacologic interventions (aminophyllines, magnesium sulfate, anti-inflammatory agents, inhaled corticosteroids, and short-acting bronchodilators) had insufficient evidence, showing either no or inconclusive effects (with the exception of the mucolytic erdosteine) or improvement only in lung function.

LIMITATION

Scant evidence for many interventions; several studies had unclear or high risk of bias and inadequate reporting of AEs.

CONCLUSION

Antibiotics and systemic corticosteroids reduce treatment failure in adults with mild to severe exacerbation of COPD.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality. (PROSPERO: CRD42018111609).

N-acetylcysteine improves oxidative stress and inflammatory response in patients with community acquired pneumonia: A randomized controlled trial

Oxidative stress is considered to be part of the pathogenic mechanism for community-acquired pneumonia (CAP) and is closely linked to inflammation. Attenuation of oxidative stress would be expected to reduce pulmonary damage. Antioxidants have been found to be effective in alleviating lung injury and protecting against damage of other organs.The aim of the study was to compare the effect of adding N-acetylcysteine (NAC) to conventional treatment versus conventional treatment on oxidative stress, inflammatory factors, and radiological changes in CAP patients.Eligible CAP patients at Weihai Municipal Hospital were stratified and randomly assigned to either NAC group or non-NAC group between August 2016 and March 2017. The NAC group received conventional treatment for pneumonia and NAC (1200 mg/d). Thenon-NAC group received conventional therapy. malondialdehyde (MDA), superoxide dismutase (SOD), total antioxidant capacity (TAOC), tumor necrosis factor-α (TNF-α), and computed tomography (CT) images were evaluated at baseline and after treatment. The primary endpoint indicators were the changes in oxidative stress parameters (MDA, TAOC, SOD) and TNF-α after treatment in the NAC group compared with those in the non-NAC group. The secondary endpoint indicator was any difference in CT scores after treatment in the NAC group compared with the non-NAC group.Baseline levels of MDA, TAOC, SOD, and TNF-α were similar between the 2 groups before treatment. Plasma levels of MDA and TNF-α decreased more (P < .05 MDA:p 0.004, TNF-α:p <0.001) in the NAC group than the non-NAC group, and there was a reliable increase in TAOC content (p 0.005). There was no significant difference in increased plasma SOD activity between the groups (p 0.368), and the NAC group did not show a greater improvement from CT scores. No NAC-related adverse effects were observed.Addition of NAC therapy for CAP patients reduced MDA and TNF-α and increased TAOC. Treatment with NAC may help to reduce oxidative and inflammatory damage in pneumonia patients.

Oxidative Stress and Inflammation in Hepatic Diseases: Therapeutic Possibilities of N-Acetylcysteine

Liver disease is highly prevalent in the world. Oxidative stress (OS) and inflammation are the most important pathogenetic events in liver diseases, regardless the different etiology and natural course. N-acetyl-l-cysteine (the active form) (NAC) is being studied in diseases characterized by increased OS or decreased glutathione (GSH) level. NAC acts mainly on the supply of cysteine for GSH synthesis. The objective of this review is to examine experimental and clinical studies that evaluate the antioxidant and anti-inflammatory roles of NAC in attenuating markers of inflammation and OS in hepatic damage. The results related to the supplementation of NAC in any form of administration and type of study are satisfactory in 85.5% (n = 59) of the cases evaluated (n = 69, 100%). Within this percentage, the dosage of NAC utilized in studies in vivo varied from 0.204 up to 2 g/kg/day. A standard experimental design of protection and treatment as well as the choice of the route of administration, with a broader evaluation of OS and inflammation markers in the serum or other biological matrixes, in animal models, are necessary. Clinical studies are urgently required, to have a clear view, so that, the professionals can be sure about the effectiveness and safety of NAC prescription.