Efficacy of N-Acetylcysteine in Idiopathic Pulmonary Fibrosis: A Systematic Review and Meta-Analysis

Efficacy of N-acetylcysteine plus pirfenidone in the treatment of idiopathic pulmonary fibrosis: a systematic review and meta-analysis

BACKGROUND

Numerous studies have demonstrated the potential of pirfenidone to enhance the prognosis of patients afflicted with idiopathic pulmonary fibrosis (IPF). Although N-acetylcysteine (NAC) is utilized as an antioxidant in IPF treatment, the combination of NAC and pirfenidone has produced inconsistent outcomes in certain studies. To assess the clinical effectiveness and safety of NAC plus pirfenidone (designated as the treatment group) versus pirfenidone monotherapy (designated as the control group), we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs).

METHODS

RCTs of NAC plus pirfenidone were reviewed searching from databases and networks of unpublished and published studies in any language. Using pair-wise meta-analysis, changes in pulmonary function test (PFT) parameters and safety were evaluated.

RESULTS

Two independent reviewers selected and obtained data from 5 RCTs (n = 398), comprising 1 study from Japan, 1 from Europe, and 3 from China. NAS plus pirfenidone as compared to pirfenidone monotherapy for IPF may not reduce the incidence of skin effects(RR 1.26 [95%CI 0.64 to 2.45]) and mortality(RR 0.35 [95%CI 0.07 to 1.68])(both moderate certainty). NAS plus pirfenidone as compared to pirfenidone monotherapy for IPF may not reduce the incidence of at least one side effects(RR 1.00 [95%CI 0.84 to 1.19]; low certainty),severe side effects(RR 0.67 [95%CI 0.30 to 1.47]; low certainty) and gastrointestinal effects(RR 0.67 [95%CI 0.41 to 1.09]; low certainty) with possibly no effect in Δ%DLco(SMD -0.17 [95%CI -0.15 to 0.48]; low certainty). Meanwhile, the effect of NAS plus pirfenidone as compared to pirfenidone monotherapy on ΔFVC(SMD 0.18 [95%CI -0.68 to 1.05]), Δ%FVC(SMD -2.62 [95%CI -5.82 to 0.59]) and Δ6MWT(SMD -0.35 [95%CI -0.98 to 0.28]) is uncertain(extremely low certainty).

CONCLUSION

Moderate certainty evidence suggests that NAS plus pirfenidone, compared to pirfenidone monotherapy for IPF, does not reduce the incidence of skin effects and mortality.

Revisiting Circulating Extracellular Matrix Fragments as Disease Markers in Myelofibrosis and Related Neoplasms

Philadelphia chromosome-negative chronic myeloproliferative neoplasms (MPNs) arise due to acquired somatic driver mutations in stem cells and develop over 10-30 years from the earliest cancer stages (essential thrombocythemia, polycythemia vera) towards the advanced myelofibrosis stage with bone marrow failure. The JAK2V617F mutation is the most prevalent driver mutation. Chronic inflammation is considered to be a major pathogenetic player, both as a trigger of MPN development and as a driver of disease progression. Chronic inflammation in MPNs is characterized by persistent connective tissue remodeling, which leads to organ dysfunction and ultimately, organ failure, due to excessive accumulation of extracellular matrix (ECM). Considering that MPNs are acquired clonal stem cell diseases developing in an inflammatory microenvironment in which the hematopoietic cell populations are progressively replaced by stromal proliferation-"a wound that never heals"-we herein aim to provide a comprehensive review of previous promising research in the field of circulating ECM fragments in the diagnosis, treatment and monitoring of MPNs. We address the rationales and highlight new perspectives for the use of circulating ECM protein fragments as biologically plausible, noninvasive disease markers in the management of MPNs.

Development of Anti-fibrotic Therapy in Stricturing Crohn's Disease: Lessons from Randomized Trials in Other Fibrotic Diseases

Intestinal fibrosis is considered an inevitable complication of Crohn's disease (CD) that results in symptoms of obstruction and stricture formation. Endoscopic or surgical treatment is required to treat the majority of patients. Progress in the management of stricturing CD is hampered by the lack of effective anti-fibrotic therapy; however, this situation is likely to change because of recent advances in other fibrotic diseases of the lung, liver and skin. In this review, we summarized data from randomized controlled trials (RCT) of anti-fibrotic therapies in these conditions. Multiple compounds have been tested for the anti-fibrotic effects in other organs. According to their mechanisms, they were categorized into growth factor modulators, inflammation modulators, 5-hydroxy-3-methylgultaryl-coenzyme A (HMG-CoA) reductase inhibitors, intracellular enzymes and kinases, renin-angiotensin system (RAS) modulators and others. From our review of the results from the clinical trials and discussion of their implications in the gastrointestinal tract, we have identified several molecular candidates that could serve as potential therapies for intestinal fibrosis in CD.

N-Acetylcysteine (NAC): Impacts on Human Health

N-acetylcysteine (NAC) is a medicine widely used to treat paracetamol overdose and as a mucolytic compound. It has a well-established safety profile, and its toxicity is uncommon and dependent on the route of administration and high dosages. Its remarkable antioxidant and anti-inflammatory capacity is the biochemical basis used to treat several diseases related to oxidative stress and inflammation. The primary role of NAC as an antioxidant stems from its ability to increase the intracellular concentration of glutathione (GSH), which is the most crucial biothiol responsible for cellular redox imbalance. As an anti-inflammatory compound, NAC can reduce levels of tumor necrosis factor-alpha (TNF-α) and interleukins (IL-6 and IL-1β) by suppressing the activity of nuclear factor kappa B (NF-κB). Despite NAC's relevant therapeutic potential, in several experimental studies, its effectiveness in clinical trials, addressing different pathological conditions, is still limited. Thus, the purpose of this chapter is to provide an overview of the medicinal effects and applications of NAC to human health based on current therapeutic evidence.

Oxidative Stress and Endoplasmic Reticulum Stress in Rare Respiratory Diseases

Several studies have shown that some rare respiratory diseases, such as alpha-1 antitrypsin deficiency (AATD), idiopathic pulmonary fibrosis (IPF), cystic fibrosis (CF), and primary ciliary dyskinesia (PCD) present oxidative stress (OS) and endoplasmic reticulum (ER) stress. Their involvement in these pathologies and the use of antioxidants as therapeutic agents to minimize the effects of OS are discussed in this review.

N-acetylcysteine and coronavirus disease 2019: May it work as a beneficial preventive and adjuvant therapy? A comprehensive review study

BACKGROUND

Coronaviruses are major pathogens of respiratory system causing different disorders, including the common cold, Middle East respiratory syndrome, and severe acute respiratory syndrome. Today's global pandemic coronavirus disease 2019 (COVID-19) has high mortality rate, with an approximate of 20% in some studies, and is 30-60 times more fatal than the common annual influenza, However, there is still no gold standard treatment for it. N-acetylcysteine (NAC) is a well-known multi-potential drug with hypothetically probable acceptable effect on COVID-related consequences, which we completely focused in this comprehensive review.

MATERIALS AND METHODS

PubMed, Scopus, Science Direct, and Google Scholar have been searched. Study eligibility criteria: efficacy of NAC in various subclasses of pathogenic events which may occur during COVID-19 infection. Efficacy of NAC for managing inflammatory or any symptoms similar to symptoms of COVID-19 was reviewed and symptom improvements were assessed.

RESULTS

Randomized clinical trials introduced NAC as an antioxidant glutathione analog and detoxifying agent promoted for different medical conditions and pulmonary disorders to alleviate influenza and reduce mortality by 50% in influenza-infected animals. The beneficial effects of NAC on viral disorders, including Epstein-Barr virus, HIV and hepatitis, and well-known vital organ damages were also exist and reported.

CONCLUSION

We classified the probable effects of NAC as oxidative-regulatory and apoptotic-regulatory roles, antiviral activities, anti-inflammatory roles, preventive and therapeutic roles in lung disorders and better oxygenation functions, supportive roles in intensive care unit admitted patients and in sepsis, positive role in other comorbidities and nonpulmonary end-organ damages or failures and even in primary COVID-associated cutaneous manifestations. Based on different beneficial effects of NAC, it could be administered as a potential adjuvant therapy for COVID-19 considering patient status, contraindications, and possible drug-related adverse events.

"A Chain Only as Strong as Its Weakest Link": An Up-to-Date Literature Review on the Bidirectional Interaction of Pulmonary Fibrosis and COVID-19

The COVID-19 pandemic rapidly became a worldwide healthcare emergency affecting millions of people, with poor outcomes for patients with chronic conditions and enormous pressure on healthcare systems. Pulmonary fibrosis (PF) has been cited as a risk factor for a more severe evolution of COVID-19, primarily because its acute exacerbations are already associated with high mortality. We reviewed the available literature on biochemical, pathophysiological, and pharmacological mechanisms of PF and COVID-19 in an attempt to foresee the particular risk of infection and possible evolution of PF patients if infected with SARS-COV-2. We also analyzed the possible role of medication and risk factors (such as smoking) in the disease's evolution and clinical course. We found out that there is a complexity of interactions between coexisting idiopathic pulmonary fibrosis/interstitial lung disease (ILD) and COVID-19 disease. Also, patients recovering from severe COVID-19 disease are at serious risk of developing PF. Smokers seem to have, in theory, a chance for a better outcome if they develop a severe form of COVID-19 but statistically are at much higher risk of dying if they become critically ill.

Targeting Neutrophils to Treat Acute Respiratory Distress Syndrome in Coronavirus Disease

This review describes targeting neutrophils as a potential therapeutic strategy for acute respiratory distress syndrome (ARDS) associated with coronavirus disease 2019 (COVID-19), a pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Neutrophil counts are significantly elevated in patients with COVID-19 and significantly correlated with disease severity. The neutrophil-to-lymphocyte ratio can serve as a clinical marker for predicting fatal complications related to ARDS in patients with COVID-19. Neutrophil-associated inflammation plays a critical pathogenic role in ARDS. The effector functions of neutrophils, acting as respiratory burst oxidants, granule proteases, and neutrophil extracellular traps, are linked to the pathogenesis of ARDS. Hence, neutrophils can not only be used as pathogenic markers but also as candidate drug targets for COVID-19 associated ARDS.

Old age-associated enrichment of peripheral T regulatory cells and altered redox status in pulmonary tuberculosis patients

Aging influences the susceptibility and prognosis to various infectious diseases including tuberculosis (TB). Despite the impairment of T-cell function and immunity in older individuals, the mechanism for the higher incidence of TB in the elderly remains largely unknown. Here, we evaluated the age-associated immune alterations, particularly in effector and Treg responses in pulmonary TB patients. We also evaluated the impact of redox status and its modulation with N-acetyl-cysteine (NAC) in elderly TB. Higher frequency of Treg cells and reduced IFN-γ positive T cells were observed among older TB patients. The elevated number of Treg cells correlated tightly with bacillary load (i.e. disease severity); which declined significantly in response to successful anti-tubercular treatment. We could rescue Myobacterium tuberculosis-specific effector T cell (Th1) responses through various in vitro approaches, for example, Treg cell depletion and co-culture experiments, blocking experiments using antibodies against IL-10, TGF-β, and programmed death-1 (PD-1) as well as NAC supplementation. We report old age-associated enrichment of Treg cells and suppression of M. tuberculosis-specific effector T (Th1) cell immune responses. Monitoring these immune imbalances in older patients may assist in immune potentiation through selectively targeting Treg cells and/or optimizing redox status by NAC supplementation.

New Insights into the Implication of Mitochondrial Dysfunction in Tissue, Peripheral Blood Mononuclear Cells, and Platelets during Lung Diseases

Lung diseases such as chronic obstructive pulmonary disease, asthma, pulmonary arterial hypertension, or idiopathic pulmonary fibrosis are major causes of morbidity and mortality. Complex, their physiopathology is multifactorial and includes lung mitochondrial dysfunction and enhanced reactive oxygen species (ROS) release, which deserves increased attention. Further, and importantly, circulating blood cells (peripheral blood mononuclear cells-(PBMCs) and platelets) likely participate in these systemic diseases. This review presents the data published so far and shows that circulating blood cells mitochondrial oxidative capacity are likely to be reduced in chronic obstructive pulmonary disease (COPD), but enhanced in asthma and pulmonary arterial hypertension in a context of increased oxidative stress. Besides such PBMCs or platelets bioenergetics modifications, mitochondrial DNA (mtDNA) changes have also been observed in patients. These new insights open exciting challenges to determine their role as biomarkers or potential guide to a new therapeutic approach in lung diseases.

Oxidative stress induces club cell proliferation and pulmonary fibrosis in Atp8b1 mutant mice

Atp8b1 (ATPase, aminophospholipid transporter, class I, type 8B, member 1) is a cardiolipin transporter in the apical membrane of lung epithelial cells. While the role of Atp8b1 in pneumonia-induced acute lung injury (ALI) has been well studied, its potential role in oxidative stress-induced ALI is poorly understood. We herein show that Atp8b1^G308V/G308V mice under hyperoxic conditions display exacerbated cell apoptosis at alveolar epithelium and aberrant proliferation of club cells at bronchiolar epithelium. This hyperoxia-induced ambivalent response in Atp8b1^G308V/G308V lungs was followed by patchy distribution of non-uniform interstitial fibrosis at late recovery phase under normoxia. Since this club cell abnormality is commonly observed between Atp8b1^G308V/G308V lungs under hyperoxic conditions and IPF lungs, we characterized this mouse fibrosis model focusing on club cells. Intriguingly, subcellular morphological analysis of IPF lungs, using transmission electron microscopy (TEM), revealed that metaplastic bronchiolar epithelial cells in fibrotic lesions and deformed type II alveolar epithelial cells (AECs) in alveoli with mild fibrosis, have common morphological features including cytoplasmic vacuolation and dysmorphic lamellar bodies. In conclusion, the combination of Atp8b1 mutation and hyperoxic insult serves as a novel platform to study unfocused role of club cells in IPF.

Oxidative Stress in Pulmonary Fibrosis

Oxidative stress has been linked to various disease states as well as physiological aging. The lungs are uniquely exposed to a highly oxidizing environment and have evolved several mechanisms to attenuate oxidative stress. Idiopathic pulmonary fibrosis (IPF) is a progressive age-related disorder that leads to architectural remodeling, impaired gas exchange, respiratory failure, and death. In this article, we discuss cellular sources of oxidant production, and antioxidant defenses, both enzymatic and nonenzymatic. We outline the current understanding of the pathogenesis of IPF and how oxidative stress contributes to fibrosis. Further, we link oxidative stress to the biology of aging that involves DNA damage responses, loss of proteostasis, and mitochondrial dysfunction. We discuss the recent findings on the role of reactive oxygen species (ROS) in specific fibrotic processes such as macrophage polarization and immunosenescence, alveolar epithelial cell apoptosis and senescence, myofibroblast differentiation and senescence, and alterations in the acellular extracellular matrix. Finally, we provide an overview of the current preclinical studies and clinical trials targeting oxidative stress in fibrosis and potential new strategies for future therapeutic interventions. © 2020 American Physiological Society. Compr Physiol 10:509-547, 2020.

The impact of alcohol use disorders on pulmonary immune cell inflammatory responses to Streptococcus pneumoniae

Community-acquired pneumonia due to Streptococcus pneumoniae occurs commonly in alcohol use disorders (AUDs). Pneumonia in the AUD patient is associated with poorer outcomes, and specific therapies to mitigate disease severity in these patients do not exist. Numerous investigations have attributed increased severity of pneumonia in AUDs to aberrant function of the alveolar macrophage (AM), a lung immune cell critical in host defense initiation. No studies have examined the response of human AMs to S. pneumoniae in AUDs. We hypothesized that the inflammatory mediators released by AMs after S. pneumoniae stimulation would differ quantitatively in individuals with AUDs compared to non-AUD participants. We further postulated that AM inflammatory mediators would be diminished after exposure to the antioxidant, N-acetylcysteine (NAC). For comparison, responses of peripheral blood mononuclear cells (PBMCs) to pneumococcal protein were also examined. Otherwise healthy participants with AUDs and smoking-matched controls underwent bronchoalveolar lavage and peripheral blood sampling to obtain AMs and PBMCs, respectively. Freshly collected cells were cultured with increasing doses of heat-killed S. pneumoniae protein, with and without exposure to N-acetylcysteine. Cell culture supernatants were collected, and inflammatory mediators were measured, including interferon (IFN)-γ, interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. IFN-γ and IL-6 were significantly higher in unstimulated AM cell culture supernatants from subjects with AUDs. After stimulation with pneumococcal protein, a dose-response and time-dependent increase in pro-inflammatory cytokine production by both AMs and PBMCs was also observed; differences were not observed between AUD and non-AUD subjects. Addition of NAC to pneumococcal-stimulated AMs and PBMCs was generally associated with diminished cytokine production, with the exception of IL-1β that was elevated in AM culture supernatants from subjects with AUDs. Our observations suggest that AUDs contribute to basal alterations in AM pro-inflammatory cytokine elaboration, but did not support consistent differences in pneumococcal-stimulated AM or PBMC inflammatory mediator secretion that were referable to AUDs.

The Role of HMGB1, a Nuclear Damage-Associated Molecular Pattern Molecule, in the Pathogenesis of Lung Diseases

Significance: High-mobility group protein box 1 (HMGB1), a ubiquitous nuclear protein, regulates chromatin structure and modulates the expression of many genes involved in the pathogenesis of lung cancer and many other lung diseases, including those that regulate cell cycle control, cell death, and DNA replication and repair. Extracellular HMGB1, whether passively released or actively secreted, is a danger signal that elicits proinflammatory responses, impairs macrophage phagocytosis and efferocytosis, and alters vascular remodeling. This can result in excessive pulmonary inflammation and compromised host defense against lung infections, causing a deleterious feedback cycle. Recent Advances: HMGB1 has been identified as a biomarker and mediator of the pathogenesis of numerous lung disorders. In addition, post-translational modifications of HMGB1, including acetylation, phosphorylation, and oxidation, have been postulated to affect its localization and physiological and pathophysiological effects, such as the initiation and progression of lung diseases. Critical Issues: The molecular mechanisms underlying how HMGB1 drives the pathogenesis of different lung diseases and novel therapeutic approaches targeting HMGB1 remain to be elucidated. Future Directions: Additional research is needed to identify the roles and functions of modified HMGB1 produced by different post-translational modifications and their significance in the pathogenesis of lung diseases. Such studies will provide information for novel approaches targeting HMGB1 as a treatment for lung diseases.

Thiol-Redox Regulation in Lung Development and Vascular Remodeling

Significance: Redox homeostasis is finely tuned and governed by distinct intracellular mechanisms. The dysregulation of this either by external or internal events is a fundamental pathophysiologic base for many pulmonary diseases. Recent Advances: Based on recent discoveries, it is increasingly clear that cellular redox state and oxidation of signaling molecules are critical modulators of lung disease and represent a final common pathway that leads to poor respiratory outcomes. Critical Issues: Based on the wide variety of stimuli that alter specific redox signaling pathways, improved understanding of the disease and patient-specific alterations are needed for the development of therapeutic targets. Further Directions: For the full comprehension of redox signaling in pulmonary disease, it is essential to recognize the role of reactive oxygen intermediates in modulating biological responses. This review summarizes current knowledge of redox signaling in pulmonary development and pulmonary vascular disease.

Chinese Herbal Medicines Compared with N-Acetylcysteine for the Treatment of Idiopathic Pulmonary Fibrosis: A Systematic Review of Randomized Controlled Trials

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a major global health problem. The prevalence of the disease appears to be increasing. There is no curative therapy for IPF except lung transplantation. Chinese herbal medicines (CHMs) are showing promise for treatment of IPF. However, their effectiveness and safety are still unclear and deserve further investigation. The aim of this systematic review is to access the efficacy and safety of CHMs in treating IPF.

METHODS

The protocol of this review is registered at PROSPERO. We searched seven main databases for randomized clinical trials (RCTs) on CHMs for IPF from their inception to June 4, 2018. The methodological quality of RCTs was assessed using the Cochrane risk of bias tool. All trials included were analyzed according to the criteria of the Cochrane Handbook. Review Manager 5.3, R-3.5.2 software, and Grade pro GDT web solution were used for data synthesis and analysis.

RESULTS

Thirteen randomized clinical trials enrolling 733 patients were included. All trials included had clear outcome indicators. The methodological quality of included trials was generally "poor." Few trials reported methods of randomization. One trial on Xuefu-zhuyu capsule assessed rate of acute exacerbation and mortality after treatment for 72 weeks and found no statistically significant difference between two groups. This meta-analysis demonstrated a significant improvement in QOL of IPF patients when CHMs was applied or combined with conventional medicine treatment. 6MWT was significantly improved in IPF patients after using CHMs or combined with conventional medicine treatment. CHMs treatment also had a certain improvement in TLC and DLCO, but the effect on FVC was not significant. Besides, CHMs failed to provide benefits in terms of PaO2. The reported adverse events were not obvious and severe.

CONCLUSIONS

Some CHMs seem effective and safe as alternative remedies for patients with IPF, suggesting that further study of CHMs in the treatment of IPF is warranted. Although this systematic review suggests that CHMs may have positive effect on quality of life, 6-minute walk test distance, and lung function (TLC, DLOC%) and seem to be relatively safe during the course of treatment, the results must be treated with great caution because of the methodological flaws of the included trials. Long-term and high-quality trials are needed in the future to provide clear evidence for the use of CHMs.

Efficacy and safety of N-acetylcysteine therapy for idiopathic pulmonary fibrosis: An updated systematic review and meta-analysis

Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal lung disease with poor prognosis and limited treatment options. N-acetylcysteine (NAC), an anti-oxidant drug, has promising potential in the treatment of IPF. In the present systematic review and meta-analysis, the efficacy and safety of NAC for IPF were investigated. The following databases were comprehensively searched for relevant studies published until August 2018: Pubmed, Embase, Cochrane library, Chinese National Knowledge Infrastructure, Wangfang Database, VIP and the Chinese Biology Medical Database. A total of 21 controlled trials assessing the efficacy and safety of NAC therapy for IPF were identified and primary outcomes [forced vital capacity (FVC), adverse side effects] and secondary outcomes [diffusing capacity for carbon monoxide (DLCO) and its percentage predicted value (DLCO%), vital capacity (VC), partial arterial oxygen pressure (PaO₂), 6-min walking distance test and mortality] were extracted for the meta-analysis. The risk ratio and mean difference or standardized mean difference with 95% confidence interval were calculated using RevMan 5.3 software. Analysis of the pooled data revealed that, compared with control treatments (routine treatment or drugs other than anti-oxidants), NAC therapy reduced the decline in lung function, as indicated by the FVC and DLCO, and slowed the progression of the disease, as indicated by the PaO₂, while complications and mortality were similar. These results suggest good efficacy, tolerability and safety of the treatment. Furthermore, subgroup analysis revealed that combined therapy including NAC for IPF might be more effective than NAC monotherapy, while oral administration of NAC was safer than inhalation. In conclusion, the results of the present review and meta-analysis provide important information that may serve as a guide regarding NAC therapy for IPF in clinical practice.

Scientific Papers and Patents on Substances with Unproven Effects. Part 2

Several examples are discussed in this review, where substances without proven effects were proposed for practical use within the scope of evidence-based medicines. The following is discussed here: generalizations of the hormesis concept and its use in support of homeopathy; phytoestrogens and soy products potentially having feminizing effects; glycosaminoglycans for the treatment of osteoarthritis and possibilities of their replacement by diet modifications; flavonoids recommended for the treatment of chronic venous insufficiency and varicose veins; acetylcysteine as a mucolytic agent and its questionable efficiency especially by an oral intake; stem cells and cell therapies. In conclusion, placebo therapies can be beneficial and ethically justifiable but it is not a sufficient reason to publish biased information. Importantly, placebo must be devoid of adverse effects, otherwise, it is named pseudo-placebo. Therapeutic methods with unproven effects should be tested in high-quality research shielded from the funding bias. Some issues discussed in this review are not entirely clear, and the arguments provided here can initiate a constructive discussion.

Cystine-based MBioF for Maintaining the Antioxidant-Oxidant Balance in Airway Diseases

Reactive oxygen species, contributing to oxidant-antioxidant imbalance, initiate damage to the airways cells, inflammatory processes, and further pathophysiological effects. Enhancing antioxidant properties is the main prophylactic and therapeutic challenge. In this work, a newly synthesized and biocompatible structure of the metal-biomolecule frameworks (MBioF) harnessing cystine as a linker and magnesium as metal nodes is presented. This structure provides crucial sulfhydryl groups of cysteine, with antioxidant activity, released stepwise in the site of delivery. We prove that once released, the compounds of MBioF increase the intracellular level of cysteine and total antioxidative capability of airway cells. Presented MBioF structures offer new perspectives for clinical applications as therapeutics or preventatives maintaining the antioxidant-oxidant balance.

NADPH oxidase, oxidative stress and fibrosis in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by damage of small vessels, immune abnormalities and exaggerated production of extracellular matrix. The etiology of the disease is unknown and the pathogenesis ill defined. However, there is consistent evidence that oxidative stress contributes to the establishment and progression of the disease. This review examines the most relevant research regarding the involvement of free radicals and of nicotinamide adenine dinucleotide phosphate oxidases (NADPH oxidases; NOX) in the pathogenesis of systemic sclerosis.

Oxidative stress in chronic lung disease: From mitochondrial dysfunction to dysregulated redox signaling

The lung is a delicate organ with a large surface area that is continuously exposed to the external environment, and is therefore highly vulnerable to exogenous sources of oxidative stress. In addition, each of its approximately 40 cell types can also generate reactive oxygen species (ROS), as byproducts of cellular metabolism and in a more regulated manner by NOX enzymes with functions in host defense, immune regulation, and cell proliferation or differentiation. To effectively regulate the biological actions of exogenous and endogenous ROS, various enzymatic and non-enzymatic antioxidant defense systems are present in all lung cell types to provide adequate protection against their injurious effects and to allow for appropriate ROS-mediated biological signaling. Acute and chronic lung diseases are commonly thought to be associated with increased oxidative stress, evidenced by altered cellular or extracellular redox status, increased irreversible oxidative modifications in proteins or DNA, mitochondrial dysfunction, and altered expression or activity of NOX enzymes and antioxidant enzyme systems. However, supplementation strategies with generic antioxidants have been minimally successful in prevention or treatment of lung disease, most likely due to their inability to distinguish between harmful and beneficial actions of ROS. Recent studies have attempted to identify specific redox-based mechanisms that may mediate chronic lung disease, such as allergic asthma or pulmonary fibrosis, which provide opportunities for selective redox-based therapeutic strategies that may be useful in treatment of these diseases.

A Chinese Herbal Formula Ameliorates Pulmonary Fibrosis by Inhibiting Oxidative Stress via Upregulating Nrf2

This study aimed to explore the protective effects of a Chinese herbal formula, Jinshui Huanxian formula (JHF), on experimental pulmonary fibrosis and its underlying mechanisms. After being treated with single dose of bleomycin (5 mg/kg) intratracheally, rats were orally administered with JHF and pirfenidone from day 1 to 42, then sacrificed at 7, 14, 28, or 42 days post-bleomycin instillation. JHF ameliorated bleomycin-induced pathological changes, collagen deposition in the rat lung and recovered pulmonary function at different days post-bleomycin instillation. In lungs of JHF-treated rats, the levels of total superoxide dismutase, catalase and glutathione were higher, and myeloperoxidase and methane dicarboxylic aldehyde were lower than those in vehicle-treated rats, respectively. Additionally, JHF inhibited the expression of NADPH oxidase 4 (NOX4) and increased the Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) in lung tissues. In vitro, JHF and ruscogenin, a compound of Ophiopogonis Radix contained in JHF, significantly inhibited transforming growth factor β1 (TGF-β1)-induced differentiation of fibroblasts. Furthermore, JHF markedly decreased the level of reactive oxygen species in TGF-β1-induced fibroblast. In line with this, upregulation of NAD(P)H: quinone oxidoreductase 1 and heme oxygenase 1, and downregulation of NOX4 were found in JHF-treated fibroblast induced by TGF-β1. While on the other hand, Nrf2 siRNA could suppress the JHF-mediated inhibition effect on alpha-smooth muscle actin (α-SMA), and FN1 expression induced by TGF-β₁ in fibroblasts. These results indicated that JHF performed remarkably therapeutic and long-term effects on pulmonary fibrosis in rat and suppressed the differentiation of fibroblast into myofibroblast through reducing the oxidative response by upregulating Nrf2 signaling. It might provide a new potential natural drug for the treatment of pulmonary fibrosis.

Evaluation of oxidative stress biomarkers in idiopathic pulmonary fibrosis and therapeutic applications: a systematic review

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF), a fatal lung disease of unknown origin, is characterized by chronic and progressive fibrosing interstitial pneumonia which progressively impairs lung function. Oxidative stress is one of the main pathogenic pathways in IPF. The aim of this systematic review was to describe the type of markers of oxidative stress identified in different biological specimens and the effects of antioxidant therapies in patients with IPF.

METHODS

We conducted a systematic search of publications listed in electronic databases (Pubmed, Web of Science, Scopus and Google Scholar) from inception to October 2017. Two investigators independently reviewed all identified articles to determine eligibility.

RESULTS

After a substantial proportion of the initially identified articles (n = 554) was excluded because they were duplicates, abstracts, irrelevant, or did not meet the selection criteria, we identified 30 studies. In each study, we critically appraised the type, site (systemic vs. local, e.g. breath, sputum, expired breath condensate, epithelial lining fluid, bronchoalveolar lavage, and lung tissue specimens), and method used for measuring the identified oxidative stress biomarkers. Furthermore, the current knowledge on antioxidant therapies in IPF was summarized.

CONCLUSIONS

A number of markers of oxidative stress, with individual advantages and limitations, have been described in patients with IPF. Nevertheless, trials of antioxidant treatments have been unable to demonstrate consistent benefits, barring recent pharmacogenomics data suggesting different results in specific genotype subgroups of patients with IPF.

Efficacy of antioxidant in idiopathic pulmonary fibrosis: A systematic review and meta-analysis

Idiopathic pulmonary fibrosis (IPF) is a chronic oxido-inflammatory disorder of the lung. Oxidative stress is widely recognized as a central feature of IPF. Antioxidant therapy has been proposed as an effective treatment for IPF. An array of clinical trials describing the therapeutic impact of these drugs have been reporting albeit with conflicting evidence points. We performed a meta-analysis of trials in which efficacy of antioxidant therapy was compared with control in IPF. Systematic literature search was conducted in PubMed, EMBASE, the Cochrane Library, CPCI-S (Conference Proceedings Citation Index-Science), ICTRP (International Clinical Trials Registry Platform), and Google Scholar till June 2016 by two independent researchers. Various outcomes such as changes in pulmonary function tests (change in vital capacity [ΔVC], change in forced vital capacity [ΔFVC], change in percentage of predicted vital capacity [Δ%VC], and change in percentage of predicted carbon monoxide diffusing capacity [Δ%DLco]), changes in 6 minutes walking test distance (Δ6MWT), rates of adverse events, and rates of death, were included. All statistical analyses were performed using RevMan V.5.3. Twelve studies (n = 1062) were identified that used antioxidants (N-acetylcysteine and lecithinized superoxide dismutase) as a treatment for IPF. Overall, there was no association of antioxidant therapy with ΔFVC (SMD = 0.27, 95% CI:-0.07 to 0.61; P = 0.12), ΔFVC (%) (SMD = -0.10, 95% CI:-0.56 to 0.36; P = 0.66) and 6MWT (SMD = -0.04, 95% CI:-0.11 to 0.20; P = 0.59) in IPF patients. However, combined antioxidant therapy was found to be associated with %VC (SMD = 0.37, 95% CI: 0.09 to 0.64; P = 0.008) and Δ%DLco (SMD = 0.15, 95% CI: 0.00 to 0.29; P = 0.05) in IPF patients. Strong evidence was obtained that the antioxidants increased adverse effects adverse events (OR = 1.56, 95% CI: 0.75 to 3.24; P = 0.23) but it did not associate mortality (OR = 0.96, 95% CI: 0.44 to 2.11; P = 0.92). The use of significant clinical heterogeneity, low statistical power, high dropout rates, duration of follow-ups, and dosing regimens of antioxidant agents. Combined antioxidant therapy seems to be a safe and effective therapy for IPF patients which provides a more beneficial effect in terms of VC, and DLco rather than monotherapy. Further randomized controlled trials with homogeneous outcome measures are needed.