Oral mucolytic drugs for exacerbations of chronic obstructive pulmonary disease: systematic review

Anti-Inflammatory and Anti-Oxidant Properties of N-Acetylcysteine: A Fresh Perspective

N-acetyl-L-cysteine (NAC) was initially introduced as a treatment for mucus reduction and widely used for chronic respiratory conditions associated with mucus overproduction. However, the mechanism of action for NAC extends beyond its mucolytic activity and is complex and multifaceted. Contrary to other mucoactive drugs, NAC has been found to exhibit antioxidant, anti-infective, and anti-inflammatory activity in pre-clinical and clinical reports. These properties have sparked interest in its potential for treating chronic lung diseases, including chronic obstructive pulmonary disease (COPD), bronchiectasis (BE), cystic fibrosis (CF), and idiopathic pulmonary fibrosis (IPF), which are associated with oxidative stress, increased levels of glutathione and inflammation. NAC's anti-inflammatory activity is noteworthy, and it is not solely secondary to its antioxidant capabilities. In ex vivo models of COPD exacerbation, the anti-inflammatory effects have been observed even at very low doses, especially with prolonged treatment. The mechanism involves the inhibition of the activation of NF-kB and neurokinin A production, resulting in a reduction in interleukin-6 production, a cytokine abundantly present in the sputum and breath condensate of patients with COPD and correlates with the number of exacerbations. The unique combination of mucolytic, antioxidant, anti-infective, and anti-inflammatory properties positions NAC as a safe, cost-effective, and efficacious therapy for a plethora of respiratory conditions.

Filamentary keratitis: A review

Filamentary keratitis (FK) is a clinical sign of underlying ocular and systemic conditions. FK can cause significant irritation, tearing, and photophobia in the eye. It is a refractory debilitating condition caused by dry eye that affects the day-to-day activities of patients. The etiopathogenesis of FK is not well known; there are numerous predisposing causes. The condition starts as a sub-epithelial or Bowman's membrane dysfunction and leads to the shedding of epithelial cells that take a strand-like form and attach to the cornea. These strands are surrounded by mucin and continue to elongate to become filaments. The filament formation is further aided by the shearing action caused by eyelid movements. Several management approaches, such as addressing the underlying causes of filamentary keratitis, administering copious lubricants, topical corticosteroids, mucolytic agents, bandage contact lenses, punctal plugs, and mechanical removal of filaments are available. The prognosis is fair, and most cases resolve with occasional recurrences. Traditionally FK has been treated with lubricants, mechanical removal, and bandage contact lenses. The newer treatments are topical immunomodulators especially that treat filamentary keratitis associated with aqueous deficient dry eye. The review describes the treatment as well as pathogenesis.

Discovery and Mechanism Study of SARS-CoV-2 3C-like Protease Inhibitors with a New Reactive Group

3CLpro is an attractive target for the treatment of COVID-19. Using the scaffold hopping strategy, we identified a potent inhibitor of 3CLpro (3a) that contains a thiocyanate moiety as a novel warhead that can form a covalent bond with Cys145 of the protein. Tandem mass spectrometry (MS/MS) and X-ray crystallography confirmed the mechanism of covalent formation between 3a and the protein in its catalytic pocket. Moreover, several analogues of compound 3a were designed and synthesized. Among them, compound 3h shows the best inhibition of 3CLpro with an IC50 of 0.322 μM and a kinact/Ki value of 1669.34 M-1 s-1, and it exhibits good target selectivity for 3CLpro against host proteases. Compound 3c inhibits SARS-CoV-2 in Vero E6 cells (EC50 = 2.499 μM) with low cytotoxicity (CC50 > 200 μM). These studies provide ideas and insights to explore and develop new 3CLpro inhibitors in the future.

Degradation kinetics and formation of regulated and emerging disinfection by-products during chlorination of two expectorants ambroxol and bromhexine

Ambroxol hydrochloride (AMB) and bromhexine hydrochloride (BRO) are classic expectorants and bronchosecretolytic pharmaceuticals. In 2022, both AMB and BRO were recommended by medical emergency department of China to alleviate cough and expectoration for symptoms caused by COVID-19. The reaction characteristics and mechanism of AMB/BRO with chlorine disinfectant in the disinfection process were investigated in this study. The reaction of chlorine with AMB/BRO were well described by a second-order kinetics model, first-order in both AMB/BRO and chlorine. The second order rate reaction constant of AMB and BRO with chlorine at pH 7.0 were 1.15 × 10² M^-1s^-1 and 2.03 × 10² M^-1s^-1, respectively. During chlorination, a new class of aromatic nitrogenous disinfection by-products (DBPs) including 2-chloro-4, 6-dibromoaniline and 2, 4, 6-tribromoaniline were identified as the intermediate aromatic DBPs by gas chromatography-mass spectrometry. The effect of chlorine dosage, pH, and contact time on the formation of 2-chloro-4, 6-dibromoaniline and 2, 4, 6-tribromoaniline were evaluated. In addition, it was found that bromine in AMB/BRO were vital bromine source to greatly promote the formation of classic brominated DBPs, with the highest Br-THMs yields of 23.8% and 37.8%, respectively. This study inspired that bromine in brominated organic compounds may be an important bromine source of brominated DBPs.

Therapeutic Potential of Small Molecules Targeting Oxidative Stress in the Treatment of Chronic Obstructive Pulmonary Disease (COPD): A Comprehensive Review

Chronic obstructive pulmonary disease (COPD) is an increasing and major global health problem. COPD is also the third leading cause of death worldwide. Oxidative stress (OS) takes place when various reactive species and free radicals swamp the availability of antioxidants. Reactive nitrogen species, reactive oxygen species (ROS), and their counterpart antioxidants are important for host defense and physiological signaling pathways, and the development and progression of inflammation. During the disturbance of their normal steady states, imbalances between antioxidants and oxidants might induce pathological mechanisms that can further result in many non-respiratory and respiratory diseases including COPD. ROS might be either endogenously produced in response to various infectious pathogens including fungi, viruses, or bacteria, or exogenously generated from several inhaled particulate or gaseous agents including some occupational dust, cigarette smoke (CS), and air pollutants. Therefore, targeting systemic and local OS with therapeutic agents such as small molecules that can increase endogenous antioxidants or regulate the redox/antioxidants system can be an effective approach in treating COPD. Various thiol-based antioxidants including fudosteine, erdosteine, carbocysteine, and N-acetyl-L-cysteine have the capacity to increase thiol content in the lungs. Many synthetic molecules including inhibitors/blockers of protein carbonylation and lipid peroxidation, catalytic antioxidants including superoxide dismutase mimetics, and spin trapping agents can effectively modulate CS-induced OS and its resulting cellular alterations. Several clinical and pre-clinical studies have demonstrated that these antioxidants have the capacity to decrease OS and affect the expressions of several pro-inflammatory genes and genes that are involved with redox and glutathione biosynthesis. In this article, we have summarized the role of OS in COPD pathogenesis. Furthermore, we have particularly focused on the therapeutic potential of numerous chemicals, particularly antioxidants in the treatment of COPD.

Mucolytic agents versus placebo for chronic bronchitis or chronic obstructive pulmonary disease

BACKGROUND

Individuals with chronic bronchitis or chronic obstructive pulmonary disease (COPD) may suffer recurrent exacerbations with an increase in volume or purulence of sputum, or both. Personal and healthcare costs associated with exacerbations indicate that therapies that reduce the occurrence of exacerbations are likely to be useful. Mucolytics are oral medicines that are believed to increase expectoration of sputum by reducing its viscosity, thus making it easier to cough it up. Improved expectoration of sputum may lead to a reduction in exacerbations of COPD.

OBJECTIVES

Primary objective• To determine whether treatment with mucolytics reduces exacerbations and/or days of disability in patients with chronic bronchitis or COPDSecondary objectives• To assess whether mucolytics lead to improvement in lung function or quality of life• To determine frequency of adverse effects associated with use of mucolytics SEARCH METHODS: We searched the Cochrane Airways Group Specialised Register and reference lists of articles on 12 separate occasions, most recently on 23 April 2019.

SELECTION CRITERIA

We included randomised studies that compared oral mucolytic therapy versus placebo for at least two months in adults with chronic bronchitis or COPD. We excluded studies of people with asthma and cystic fibrosis.

DATA COLLECTION AND ANALYSIS

This review analysed summary data only, most derived from published studies. For earlier versions, one review author extracted data, which were rechecked in subsequent updates. In later versions, review authors double-checked extracted data and then entered data into RevMan 5.3 for analysis.

MAIN RESULTS

We added four studies for the 2019 update. The review now includes 38 trials, recruiting a total of 10,377 participants. Studies lasted between two months and three years and investigated a range of mucolytics, including N-acetylcysteine, carbocysteine, erdosteine, and ambroxol, given at least once daily. Many studies did not clearly describe allocation concealment, and we had concerns about blinding and high levels of attrition in some studies. The primary outcomes were exacerbations and number of days of disability.Results of 28 studies including 6723 participants show that receiving mucolytics may be more likely to be exacerbation-free during the study period compared to those given placebo (Peto odds ratio (OR) 1.73, 95% confidence interval (CI) 1.56 to 1.91; moderate-certainty evidence). However, more recent studies show less benefit of treatment than was reported in earlier studies in this review. The overall number needed to treat with mucolytics for an average of nine months to keep an additional participant free from exacerbations was eight (NNTB 8, 95% CI 7 to 10). High heterogeneity was noted for this outcome (I² = 62%), so results need to be interpreted with caution. The type or dose of mucolytic did not seem to alter the effect size, nor did the severity of COPD, including exacerbation history. Longer studies showed smaller effects of mucolytics than were reported in shorter studies.Mucolytic use was associated with a reduction of 0.43 days of disability per participant per month compared with use of placebo (95% CI -0.56 to -0.30; studies = 9; I² = 61%; moderate-certainty evidence). With mucolytics, the number of people with one or more hospitalisations was reduced, but study results were not consistent (Peto OR 0.68, 95% CI 0.52 to 0.89; participants = 1788; studies = 4; I² = 58%; moderate-certainty evidence). Investigators reported improved quality of life with mucolytics (mean difference (MD) -1.37, 95% CI -2.85 to 0.11; participants = 2721; studies = 7; I² = 64%; moderate-certainty evidence). However, the mean difference did not reach the minimal clinically important difference of -4 units, and the confidence interval includes no difference. Mucolytic treatment was associated with a possible reduction in adverse events (OR 0.84, 95% CI 0.74 to 0.94; participants = 7264; studies = 24; I² = 46%; moderate-certainty evidence), but the pooled effect includes no difference if a random-effects model is used. Several studies that could not be included in the meta-analysis reported high numbers of adverse events, up to a mean of five events per person during follow-up. There was no clear difference between mucolytics and placebo for mortality, but the confidence interval is too wide to confirm that treatment has no effect on mortality (Peto OR 0.98, 95% CI 0.51 to 1.87; participants = 3527; studies = 11; I² = 0%; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

In participants with chronic bronchitis or COPD, we are moderately confident that treatment with mucolytics leads to a small reduction in the likelihood of having an acute exacerbation, in days of disability per month and possibly hospitalisations, but is not associated with an increase in adverse events. There appears to be limited impact on lung function or health-related quality of life. Results are too imprecise to be certain whether or not there is an effect on mortality. Our confidence in the results is reduced by high levels of heterogeneity in many of the outcomes and the fact that effects on exacerbations shown in early trials were larger than those reported by more recent studies. This may be a result of greater risk of selection or publication bias in earlier trials, thus benefits of treatment may not be as great as was suggested by previous evidence.

Mucoactive Agents in the Therapy of Upper Respiratory Airways Infections: Fair to Describe Them Just as Mucoactive?

Background

Upper and lower respiratory tract infections are common conditions for which medical advice is sought, and their management relies on the use of prescription and over-the-counter (OTC) medicines. Ambroxol, bromhexine, carbocysteine, erdosteine, N-acetyl cysteine (NAC), and sobrerol are mucoactive agents for which clinical trials have been conducted, have been awarded well-established status by regulatory authorities, and are available as OTC or prescription products.

Objective

To briefly review the evidence-based efficacy and safety of these substances in the therapy of upper respiratory airways infections.

Methods

We conducted searches in MEDLINE and other databases for clinical trials and reviews done on the efficacy and safety of ambroxol, bromhexine, carbocysteine, erdosteine, NAC, and sobrerol.

Results

Clinical trials have shown that these mucolytics have an important place in the relief of cough symptoms by easing the elimination of mucus. All drugs have shown comparable efficacy in the symptomatic treatment of productive cough, with some shared characteristics and some specific features.

Conclusions and relevance

All mucolytics reviewed have a good safety profile, although some precautions should be taken when using ambroxol and bromhexine, and the use of NAC and carbocysteine should be monitored in special patient groups. Overall, however, the available evidence from randomised, controlled, and observational trials, as well as pragmatic, real-life experience, suggests that these products are useful in the therapy of upper respiratory airways infections, including bronchitis, sinusitis, and rhinosinusitis.

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.

Effects of Modified Zhisou Powder on Airway Mucus Production in Chronic Obstructive Pulmonary Disease Model Rats with Cold-Dryness Syndrome

Objective. In China, the Chinese medicine formula modified zhisou powder (MZP) is commonly used to treat COPD with cold-dryness syndrome (CDSCOPD) to relieve cough and sputum. However, the underlying mechanisms of MZP on treating CDSCOPD remain to be elucidated. Methods. COPD and CDSCOPD rat models were established; MZP was given to CDSCOPD rats in the last 7 days of the 97-day model establishment. Then the rats were subjected to lung function measurement. Pathological changes in lungs were observed through paraffin section and H&E staining. The mRNA and protein levels of AQP1, 4, and 5 and Muc5AC and Muc5B in lung were determined by quantitative RT-PCR and western blotting. NE levels was determined by ELISA. Results. The impaired lung functions were observed in rats exposed to cigarette smoke. Among all parameters evaluating lung functions, only tidal volume demonstrates a further decrease in CDSCOPD when compared with COPD, indicating further impaired pulmonary ventilation functions upon cold-dryness stimulation. The intervention of MZP effectively improved lung functions parameters, prevented the inflammations, and eliminated the increases of AQP4 and 5 and the decrease of Muc5AC in lung. Conclusion. MZP probably improves pulmonary functions in CDSCOPD through inhibiting lung inflammation, increasing expressions of AQPs, and decreasing Muc5AC expression in lung.

How Evidence-Based is our Practice in a Hong Kong Emergency Department?

Objective

To evaluate how evidence-based our daily practice was.

Design

Retrospective study.

Setting

Emergency department of a public district hospital.

Patients and Methods

Between 1st August 2000 to 7th August 2000, 91 patients' records were chosen at random. A chief diagnosis was assigned for each patient. Corresponding treatments were reviewed by searching relevant randomised controlled trials (RCTs), systematic reviews and meta-analyses. Each patient had only one chief diagnosis but could have multiple interventions for that diagnosis.

Results

Out of 91 records, 14 were discarded. All of them had not been given any intervention and 11 required admission. For the remaining 77 records, there were 38 subjects in medical, paediatric, or gynaecological specialties and 39 in surgical or orthopaedic specialties. Intervention(s) given for each subject were then searched electronically through our hospital Knowledge Gateway and the results were expressed as either EBM-positive or EBM-negative. “EBM-positive” interventions denoted a support by RCTs. “EBM-negative” interventions denoted an absence of any supportive RCTs. Each patient might have EBM-positive and/or EBM-negative interventions together if that patient received more than one treatment. There were 52 patients (52/77 = 68%) who had one of their interventions being RCT-supported. The majority were patients with (1) antipyretic use of paracetamol in upper respiratory tract infection, or (2) control of pain by nonsteroidal anti-inflammatory drug, dologesic and paracetamol. There were 25 patients (25/77 = 32%) who did not receive any RCT-supported interventions. Concurrently 53 patients out of 77 (69%) received EBM-negative interventions. The majority were patients with (1) the use of antibiotics, antitussives and antihistamines in upper respiratory tract infection, (2) antispasmodics in gastroenteritis or patients with nonspecific abdominal pain, and (3) the use of analgesic balm in minor orthopaedic complaints.

Conclusion

Sixty-eight percent of patients had EBM-positive interventions. Thirty-two percent of patients did not receive any EBM-positive intervention. It was quite encouraging as compared to studies in other specialties with similar design. Concurrently 69% of patients had also been given EBM-negative interventions. There were areas for improvement if we were to implement EBM practice in the emergency department.

Evaluation of the inhibitory effect of N-acetyl-L-cysteine on Babesia and Theileria parasites

N-acetyl-L-cysteine is known to have antibacterial, antiviral, antimalarial, and antioxidant activities. Therefore, the in vitro inhibitory effect of this hit was evaluated in the present study on the growth of Babesia and Theileria parasites. The in vitro growth of Babesia bovis, Babesia bigemina, Babesia divergens, Theileria equi, and Babesia caballi that were tested was significantly inhibited (P < 0.05) by micromolar concentrations of N-acetyl-L-cysteine. The inhibitory effect of N-acetyl-L-cysteine was synergistically potentiated when used in combination with diminazene aceturate on B. bovis and B. caballi cultures. These results indicate that N-acetyl-L-cysteine might be used as a drug for the treatment of babesiosis, especially when used in combination with diminazene aceturate.

Review: Do we need new antibiotics for treating exacerbations of COPD?

Exacerbations may produce permanent impairment in lung function and health status in patients with COPD. Up to 70% of episodes have a bacterial etiology, being of mixed viral infection in some cases. The new, more active antibiotics have demonstrated better eradication of bacteria in the airways and, consequently, prolongation of the time to the next exacerbation. However, the ability of bacteria to develop resistance to the antibiotics currently used warrants novel research into new families of antimicrobials, and the adoption of new strategies such as the prevention of exacerbations, nebulized antibiotic treatment or the use of antibiotics in combination.

Mucolytic Effectiveness of Tyloxapol in Chronic Obstructive Pulmonary Disease - A Double-Blind, Randomized Controlled Trial

Objective

Mucoactive drugs should increase the ability to expectorate sputum and, ideally, have anti-inflammatory properties. The aim of the study was to evaluate the mucolytic activity of Tyloxapol compared to saline (0.9%) in COPD.

Design

A randomized, placebo-controlled, double-blinded crossover, clinical trial was carried out. Patients were randomly assigned to either inhale 5 ml Tyloxapol 1% or saline 0.9% solution three times daily for 3 weeks and vice versa for another 3 weeks. 28 patients (18 male, 10 female, 47 to 73 years old, median age 63.50) were screened, 21 were treated and 19 patients completed the study per protocol.

Results

A comparison of the two treatment phases showed that the primary endpoint sputum weight was statistically significant higher when patients inhaled Tyloxapol (mean 4.03 g, 95% CI: 2.34–5.73 g at week 3) compared to saline (mean 2.63 g, 95% CI: 1.73–3.53 g at week 3). The p-value at three weeks of treatment was 0.041 between treatment arms. Sputum cells decreased during the Tyloxapol treatment after 3 weeks, indicating that Tyloxapol might have some anti-neutrophilic properties. Lung function parameters (FVC, FEV₁, RV, and RV/TLC) remained stable during the study, and no treatment effect was shown. Interestingly, there was a mean increase in all inflammatory cytokines (IL-1β, IL-6, and IL-8) during the saline treatment from day 1 to week 3, whereas during the Tyloxapol treatment, all cytokines decreased. Due to the small sample size and the large individual variation in sputum cytokines, these differences were not significant. However, analyses confirmed that Tyloxapol has significant anti-inflammatory properties in vitro. Despite the high number of inhalations (more than 1000), only 27 adverse events (20 during the Tyloxapol and seven during saline) were recorded. Eleven patients experienced AEs under Tyloxapol and six under saline treatment, which indicates that inhalation of saline or Tyloxapol is a very safe procedure.

Conclusion

Our study demonstrated that inhalation of Tyloxapol by patients with COPD is safe and superior to saline and has some anti-inflammatory effects.

Trial Registration

ClinicalTrials.gov NCT02515799

Corticosteroid insensitivity in smokers with asthma : clinical evidence, mechanisms, and management

Corticosteroids are the most effective treatment for asthma, but the therapeutic response varies considerably between individuals. Several clinical studies have found that smokers with asthma are insensitive to the beneficial effects of short- to medium-term inhaled corticosteroid treatment compared with non-smokers with asthma. It is estimated that 25% of adults in most industrialized countries smoke cigarettes, and similar surveys amongst asthmatic individuals suggest that the prevalence of smoking in this grouping mirrors that found in the general population. Therefore, cigarette smoking is probably the most common cause of corticosteroid insensitivity in asthma. Cigarette smoking and asthma are also associated with poor symptom control and an accelerated rate of decline in lung function. The mechanism of corticosteroid insensitivity in smokers with asthma is currently unexplained but could be due to alterations in airway inflammatory cell phenotypes, changes in glucocorticoid receptor alpha/beta ratio, and/or reduced histone deacetylase activity. Smoking cessation should be encouraged in all smokers with asthma. Short-term benefits include improvements in lung function and asthma control. However, the numbers of sustained quitters is disappointingly small. Additional or alternative drugs need to be identified to treat those individuals who are unable to stop smoking or who have persistent symptoms following smoking cessation.

N-acetylcysteine in COPD: why, how, and when?

Oxidants have long been recognized to have an important role in the pathogenesis of COPD, and in this cigarette smoke has a strong responsibility, because it generates a conspicuous amount of oxidant radicals able to modify the structure of the respiratory tract and to enhance several mechanisms that sustain lung inflammation in COPD. In fact, oxidative stress is highly increased in COPD and natural antioxidant capacities, mainly afforded by reduced glutathione, are often overcome. Thus an exogenous supplementation of antioxidant compounds is mandatory to at least partially counteract the oxidative stress. For this purpose N-acetylcysteine has great potentialities due to its capacity of directly contrasting oxidants with its free thiols, and to the possibility it has of acting as donor of cysteine precursors aimed at glutathione restoration. Many studies in vitro and in vivo have already demonstrated the antioxidant capacity of NAC. Many clinical studies have long been performed to explore the efficacy of NAC in COPD with altern results, especially when the drug was used at very low dosage and/or for a short period of time. More recently, several trials have been conducted to verify the appropriateness of using high-dose NAC in COPD, above all to decrease the exacerbations rate. The results have been encouraging, even if some of the data come from the most widely sized trials that have been conducted in Chinese populations. Although other evidence should be necessary to confirm the results in other populations of patients, high-dose oral NAC nevertheless offers interesting perspectives as add-on therapy for COPD patients.

Dissecting asthma pathogenesis through study of patterns of cellular traffic indicative of molecular switches operative in inflammation

Background:

Inflammation and degeneration are the two edged swords that impale a pulmonary system with the maladies like asthma and idiopathic pulmonary fibrosis. To explore critical role players that orchestrate the etiology and pathogenesis of these diseases, we used various lung disease models in mice in specific genetic knockout templates.

Materials and methods:

Acute and chronic allergic asthma and idiopathic pulmonary fibrosis model in mouse was developed in various genetic knockout templates namely α4^{Δ/ Δ}(α41-/-), β2-/-, and α4-/- β2 mice, and the following parameters were measured to assess development of composite asthma phenotype- (i) airway hyperresponsiveness to methacholine by measuring lung resistance and compliance by invasive and P_enh by non-invasive plethysmography as well as lung resistance and compliance using invasive plethysmography, (ii) in situ inflammation status in lung parenchyma and lung interstitium and also resultant airway remodelling measured by histochemical staining namely Masson’s Trichrome staining and Hematoxylin&Eosin staining, (iii) formation of metaplastic goblet cells around lung airways by Alcian blue dye, (iv) measurement of Th1 and Th2 cytokines in serum and bronchoalveolar lavage fluid (BALf), (v) serum allergen-specific IgE. Specifically, ovalbumin-induced acute allergic asthma model in mice was generated in WT (wildtype) and KO (knockout) models and readouts of the composite asthma phenotype viz. airway hypersensitivity, serum OVA-specific IgE and IgG, Th2 cytokine in bronchoalveolar lavage fluid (BALf) and lymphocyte cell subsets viz. T, B cells, monocytes, macrophages, basophils, mast cells and eosinophils (by FACS and morphometry in H&E stained cell smears) were assessed in addition to lung and lymph node histology.

Results:

We noticed a pattern of cellular traffic between bone marrow (BM)→ peripheral blood (PB) → lung parenchyma (LP) → (BALf) in terms of cellular recruitment of key cell sub-types critical for onset and development of the diseases which is different for maintenance and exacerbations in chronic cyclically occurring asthma that leads to airway remodelling. While inflammation is the central theme of this particular disease, degeneration and shift in cellular profile, subtly modifying the clinical nature of the disease were also noted. In addition we recorded the pattern of cell movement between the secondary lymphoid organs namely, the cervical, axillary, ingunal, and mesenteric lymph nodes vis-à-vis spleen and their sites of poiesis BM, PB and lung tissue. While mechanistic role is the chief domain of the integrins (α4 i.e. VLA-4 or α4β1, VCAM-1; β2 i.e. CD18 or ICAM-1).

Concluding remarks:

The present paper thoroughly compares and formulates the pattern of cellular traffic among the three nodes of information throughput in allergic asthma immunobiology, namely, primary lymphoid organs (PLO), secondary lymphoid organs (SLO), and tissue spaces and cells where inflammation and degeneration is occurring within the purview of the disease pathophysiological onset and ancillary signals in the above models and reports some interesting findings with respect to adult lung stem cell niches and its resident progenitors and their role in pathogenesis and disease amelioration.

Mucolytic agents versus placebo for chronic bronchitis or chronic obstructive pulmonary disease

BACKGROUND

Individuals with chronic bronchitis or chronic obstructive pulmonary disease (COPD) may suffer recurrent exacerbations with an increase in volume or purulence of sputum, or both. Personal and healthcare costs associated with exacerbations indicate that any therapy that reduces the occurrence of exacerbations is useful. A marked difference among countries in terms of prescribing of mucolytics reflects variation in perceptions of their effectiveness.

OBJECTIVES

Primary objective• To determine whether treatment with mucolytics reduces frequency of exacerbations and/or days of disability in patients with chronic bronchitis or chronic obstructive pulmonary disease. Secondary objectives• To assess whether mucolytics lead to improvement in lung function or quality of life.• To determine frequency of adverse effects associated with use of mucolytics.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register and reference lists of articles on 10 separate occasions, most recently in July 2014.

SELECTION CRITERIA

We included randomised studies that compared oral mucolytic therapy versus placebo for at least two months in adults with chronic bronchitis or COPD. We excluded studies of people with asthma and cystic fibrosis.

DATA COLLECTION AND ANALYSIS

This review analysed summary data only, most derived from published studies. For earlier versions, one review author extracted data, which were rechecked in subsequent updates. In later versions, review authors double-checked extracted data and then entered data into RevMan for analysis.

MAIN RESULTS

We added four studies for the 2014 update. The review now includes 34 trials, recruiting a total of 9367 participants. Many studies did not clearly describe allocation concealment; hence selection bias may have inflated the results, which reduces our confidence in the findings.Results of 26 studies with 6233 participants show that the likelihood that a patient could be exacerbation-free during the study period was greater among mucolytic groups (Peto odds ratio (OR) 1.75, 95% confidence interval (CI) 1.57 to 1.94). However, more recent studies show less benefit of treatment than was reported in earlier studies in this review. The overall number needed to treat with mucolytics for an additional beneficial outcome for an average of 10 months - to keep an additional participant free from exacerbations - was eight (NNTB 8, 95% CI 7 to 10). Use of mucolytics was associated with a reduction of 0.03 exacerbations per participant per month (mean difference (MD) -0.03, 95% CI -0.04 to -0.03; participants = 7164; studies = 28; I(2) = 85%) compared with placebo, that is, about 0.36 per year, or one exacerbation every three years. Very high heterogeneity was noted for this outcome, so results need to be interpreted with caution. The type or dose of mucolytic did not seem to alter the effect size, nor did the severity of COPD, including exacerbation history. Longer studies showed smaller effects of mucolytics than were reported in shorter studies.Mucolytic use was associated with a reduction of 0.43 days of disability per participant per month compared with placebo (95% CI -0.56 to -0.30; studies = 13; I(2) = 61%). With mucolytics, the number of people with one or more hospitalisations was reduced, but study results were not consistent (Peto OR 0.68, 95% CI 0.52 to 0.89; participants = 1788; studies = 4; I(2) = 58%). Investigators reported improved quality of life with mucolytics (MD -2.64, 95% CI -5.21 to -0.08; participants = 2231; studies = 5; I(2) = 51%). Although this mean difference did not reach the minimal clinically important difference of -4 units, we cannot assess the population impact, as we do not have the data needed to carry out a responder analysis. Mucolytic treatment was not associated with any significant increase in the total number of adverse effects, including mortality (Peto OR 1.03, 95% CI 0.52 to 2.03; participants = 2931; studies = 8; I(2) = 0%), but the confidence interval is too wide to confirm that the treatment has no effect on mortality.

AUTHORS' CONCLUSIONS

In participants with chronic bronchitis or COPD, we are moderately confident that treatment with mucolytics may produce a small reduction in acute exacerbations and a small effect on overall quality of life. Our confidence in the results is reduced by the fact that effects on exacerbations shown in early trials were larger than those reported by more recent studies, possibly because the earlier smaller trials were at greater risk of selection or publication bias, thus benefits of treatment may not be as great as was suggested by previous evidence.

High-dose N-acetylcysteine in stable COPD: the 1-year, double-blind, randomized, placebo-controlled HIACE study

BACKGROUND

The mucolytic and antioxidant effects of N-acetylcysteine (NAC) may have great value in COPD treatment. However, beneficial effects have not been confirmed in clinical studies, possibly due to insufficient NAC doses and/or inadequate outcome parameters used. The objective of this study was to investigate high-dose NAC plus usual therapy in Chinese patients with stable COPD.

METHODS

The 1-year HIACE (The Effect of High Dose N-acetylcysteine on Air Trapping and Airway Resistance of Chronic Obstructive Pulmonary Disease-a Double-blinded, Randomized, Placebo-controlled Trial) double-blind trial conducted in Kwong Wah Hospital, Hong Kong, randomized eligible patients aged 50 to 80 years with stable COPD to NAC 600 mg bid or placebo after 4-week run-in. Lung function parameters, symptoms, modified Medical Research Council (mMRC) dyspnea and St. George's Respiratory Questionnaire (SGRQ) scores, 6-min walking distance (6MWD), and exacerbation and admission rates were measured at baseline and every 16 weeks for 1 year.

RESULTS

Of 133 patients screened, 120 were eligible (93.2% men; mean age, 70.8±0.74 years; %FEV1 53.9±2.0%). Baseline characteristics were similar in the two groups. At 1 year, there was a significant improvement in forced expiratory flow 25% to 75% (P=.037) and forced oscillation technique, a significant reduction in exacerbation frequency (0.96 times/y vs 1.71 times/y, P=.019), and a tendency toward reduction in admission rate (0.5 times/y vs 0.8 times/y, P=.196) with NAC vs placebo. There were no significant between-group differences in mMRC dypsnea score, SGRQ score, and 6MWD. No major adverse effects were reported.

CONCLUSION

In this study, 1-year treatment with high-dose NAC resulted in significantly improved small airways function and decreased exacerbation frequency in patients with stable COPD.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01136239; URL: www.clinicaltrials.gov.

A formulation for in situ lysis of mucin secreted in pseudomyxoma peritonei

Although numerous clinical attempts have been made to disintegrate mucin secreted by pseudomyxoma peritonei (PMP), none are clinically recommended. Through examination of the pharmacologic characteristics of two novel agents, we titrated an optimized combination of bromelain and N-acetyl cysteine (NAC) that demonstrates in vitro and in vivo efficacy in the dissolution of mucinous ascites from PMP. In the in vitro experiments, 1 g of mucin was incubated in varying concentrations of bromelain (0-400 µg/ml) and NAC (0-5%) individually followed by a combination before arriving at a therapeutic combination dose of 300 µg/ml bromelain+4% NAC. This established an effective dose of bromelain 300 µg/ml+4% NAC at pH 7.0, when tested in a rat model implanted with 3 g of mucin intraperitoneally (IP). IP administration of the drug in a rat model of PMP was shown to result in mucin disintegration within 72 hr with no toxicity observed.

Strategies to decrease ongoing oxidant burden in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality and morbidity globally, and its development is mainly associated with tobacco/biomass smoke-induced oxidative stress. Hence, targeting systemic and local oxidative stress with agents that can balance the antioxidant/redox system can be expected to be useful in the treatment of COPD. Preclinical and clinical trials have revealed that antioxidants/redox modulators can detoxify free radicals and oxidants, control expression of redox and glutathione biosynthesis genes, chromatin remodeling and inflammatory gene expression; and are especially useful in preventing COPD exacerbations. In this review, various novel approaches and problems associated with these approaches in COPD are reviewed.

Mucolytic agents for chronic bronchitis or chronic obstructive pulmonary disease

BACKGROUND

Individuals with chronic bronchitis or chronic obstructive pulmonary disease (COPD) may suffer recurrent exacerbations with an increase in volume or purulence of sputum, or both. Because of the personal and healthcare costs associated with exacerbations, any therapy that reduces the number of exacerbations is useful. There is a marked difference among countries in terms of prescribing of mucolytics depending on whether or not they are perceived to be effective.

PRIMARY OBJECTIVE

to determine if treatment with mucolytics reduces the frequency of exacerbations, days of disability, or both, in participants with chronic bronchitis or chronic obstructive pulmonary disease, or both.

SECONDARY OBJECTIVES

to determine if mucolytics lead to an improvement in lung function or quality of life and to determine the frequency of adverse effects associated with mucolytics.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register and reference lists of articles on ten separate occasions, the most recent being in July 2012.

SELECTION CRITERIA

We included randomised studies that compared oral mucolytic therapy with placebo for at least two months in adults with chronic bronchitis or COPD. We excluded studies of people with asthma and cystic fibrosis.

DATA COLLECTION AND ANALYSIS

The review analysed summary data only, the majority from published studies. For earlier versions, one author extracted data, which was rechecked in subsequent updates. In later versions, we double-checked data extraction. We then entered data into RevMan for analysis.

MAIN RESULTS

Two further trials have been added to the review for the 2012 update. There are now 30 trials in the review, recruiting a total of 7436 participants. Allocation concealment was not clearly described in the early trials, and selection bias may have inflated the results, which reduces our confidence in the findings of these trials.The likelihood of being exacerbation-free during the study period (22 trials in 4886 participants with a mean duration of 10 months) was greater in the mucolytic group for the double-blind trials (Peto odds ratio (OR) 1.84; 95% confidence interval (CI) 1.63 to 2.07). However, the more recent trials show less benefit of treatment than the earlier trials included in this review. The overall number needed to treat with mucolytics to keep an additional participant free from exacerbations over 10 months was seven (NNTB 7; 95% CI 6 to 9). The use of mucolytics was associated with a reduction of 0.04 exacerbations per participant per month (95% CI -0.04 to -0.03) compared with placebo; that is about 0.48 per year, or one exacerbation every two years. There was very high heterogeneity in this outcome (I(2) = 87%) so results need to be interpreted with caution.The number of days of disability per month also fell (mean difference (MD) -0.48; 95% CI -0.65 to -0.30) in 12 trials on 2305 participants. There was no clinically important improvement in lung function or consistent impact on quality of life with mucolytics. Mucolytic treatment was not associated with any significant increase in adverse effects, including mortality (Peto OR 0.75; 95% CI 0.35 to 1.64) in six trials on 1821 participants.

AUTHORS' CONCLUSIONS

In participants with chronic bronchitis or COPD, treatment with a mucolytic may produce a small reduction in acute exacerbations, but may have little or no effect on the overall quality of life. The effects on exacerbations shown in early trials were larger than those found in the more recent studies. This may be because the earlier smaller trials were at higher risk of selection or publication bias, so the benefits of treatment may not be as large as suggested by the previous evidence.

Glutathione supplementation attenuates lipopolysaccharide-induced mitochondrial dysfunction and apoptosis in a mouse model of acute lung injury

Acute lung injury (ALI) is a life threatening condition associated with hypoxemia, diffuse alveolar damage, inflammation, and loss of lung function. Lipopolysaccharide (LPS; endotoxin) from the outer membrane of Gram-negative bacteria is a major virulence factor involved in the development of ALI. The depletion of glutathione (GSH), an essential intra- and extra-cellular protective antioxidant, by LPS is an important event that contributes to the elevation in reactive oxygen species. Whether restoring GSH homeostasis can effectively ameliorate mitochondrial dysfunction and cellular apoptosis in ALI is unknown and therefore, was the focus of this study. In peripheral lung tissue of LPS-treated mice, hydrogen peroxide and protein nitration levels were significantly increased. Pre-treatment with GSH-ethyl ester (GSH-EE) prevented this increase in oxidative stress. LPS also increased the lactate/pyruvate ratio, attenuated SOD2 protein levels, and decreased ATP levels in the mouse lung indicative of mitochondrial dysfunction. Again, GSH-EE treatment preserved the mitochondrial function. Finally, our studies showed that LPS induced an increase in the mitochondrial translocation of Bax, caspase 3 activation, and nuclear DNA fragmentation and these parameters were all prevented with GSH-EE. Thus, this study suggests that GSH-EE supplementation may reduce the mitochondrial dysfunction associated with ALI.

Antioxidant pharmacological therapies for COPD

Increased oxidative stress occurs in the lungs and systemically in COPD, which plays a role in many of the pathogenic mechanisms in COPD. Hence, targeting local lung and systemic oxidative stress with agents that modulate the antioxidants/redox system or boost endogenous antioxidants would be a useful therapeutic approach in COPD. Thiol antioxidants (N-acetyl-l-cysteine [NAC] and N-acystelyn, carbocysteine, erdosteine, and fudosteine) have been used to increase lung thiol content. Modulation of cigarette smoke (CS) induced oxidative stress and its consequent cellular changes have also been reported to be effected by synthetic molecules, such as spin traps (α-phenyl-N-tert-butyl nitrone), catalytic antioxidants (superoxide dismutase [ECSOD] mimetics), porphyrins, and lipid peroxidation and protein carbonylation blockers/inhibitors (edaravone and lazaroids/tirilazad). Preclinical and clinical trials have shown that these antioxidants can reduce oxidative stress, affect redox and glutathione biosynthesis genes, and proinflammatory gene expression. In this review the approaches to enhance lung antioxidants in COPD and the potential beneficial effects of antioxidant therapy on the course of the disease are discussed.

Neutrophil activation in severe, early-onset COPD patients versus healthy non-smoker subjects in vitro: effects of antioxidant therapy

BACKGROUND

Neutrophils and oxidative stress have been implicated in the pathogenesis of COPD. Severe, early-onset COPD is characterized by a rapid decline in the lung function at an early age; however, nothing is known about neutrophil activation in COPD patients.

OBJECTIVES

The aim of this study was to evaluate peripheral blood neutrophil activation in severe, early-onset COPD patients versus healthy non-smokers and the effect of N-acetyl-L-cysteine (NAC) on neutrophil activation in vitro.

METHODS

Neutrophils were isolated from 15 severe, early-onset COPD patients and 15 age-matched healthy subjects and stimulated with N-formyl-Met-Leu-Phe (fMLP) in the presence or absence of NAC (10 μM to 10 mM). Neutrophil chemotaxis, elastase release, reactive oxygen species (ROS), intracellular thiols and apoptosis were measured by Boyden chamber, spectrofluorometry, CMFDA and H2DCF-DA dyes and by annexin V-FITC, respectively.

RESULTS

Chemotaxis of peripheral blood neutrophils from COPD patients in response to fMLP was 30% more increased than that observed in healthy subjects. Elastase release in response to fMLP was 2-fold higher in neutrophils from COPD patients versus healthy subjects. Intracellular thiol levels were 30% lower in COPD and ROS was approximately 30% higher in COPD versus healthy neutrophils. Spontaneous apoptosis showed no differences in both groups of patients and fMLP-induced apoptosis was higher in COPD. Pre-treatment with the antioxidant NAC effectively attenuated neutrophil chemotaxis, elastase release and ROS as well as effectively increased thiol levels in COPD.

CONCLUSIONS

Neutrophils in severe, early-onset COPD patients are highly activated and this is alleviated by NAC in vitro.

Pharmacological antioxidant strategies as therapeutic interventions for COPD

Cigarette/tobacco smoke/biomass fuel-induced oxidative and aldehyde/carbonyl stress are intimately associated with the progression and exacerbation of chronic obstructive pulmonary disease (COPD). Therefore, targeting systemic and local oxidative stress with antioxidants/redox modulating agents, or boosting the endogenous levels of antioxidants are likely to have beneficial effects in the treatment/management of COPD. Various antioxidant agents, such as thiol molecules (glutathione and mucolytic drugs, such as N-acetyl-L-cysteine and N-acystelyn, erdosteine, fudosteine, ergothioneine, and carbocysteine), have been reported to modulate various cellular and biochemical aspects of COPD. These antioxidants have been found to scavenge and detoxify free radicals and oxidants, regulate of glutathione biosynthesis, control nuclear factor-kappaB (NF-kappaB) activation, and hence inhibiting inflammatory gene expression. Synthetic molecules, such as specific spin traps like α-phenyl-N-tert-butyl nitrone, a catalytic antioxidant (ECSOD mimetic), porphyrins (AEOL 10150 and AEOL 10113), and a superoxide dismutase mimetic M40419, iNOS and myeloperoxidase inhibitors, lipid peroxidation inhibitors/blockers edaravone, and lazaroids/tirilazad have also been shown to have beneficial effects by inhibiting cigarette smoke-induced inflammatory responses and other carbonyl/oxidative stress-induced cellular alterations. A variety of oxidants, free radicals, and carbonyls/aldehydes are implicated in the pathogenesis of COPD, it is therefore, possible that therapeutic administration or supplementation of multiple antioxidants and/or boosting the endogenous levels of antioxidants will be beneficial in the treatment of COPD. This review discusses various novel pharmacological approaches adopted to enhance lung antioxidant levels, and various emerging beneficial and/or prophylactic effects of antioxidant therapeutics in halting or intervening the progression of COPD. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.

Oxidative stress in asthma

Asthma is a chronic inflammatory lung disease that results in airflow limitation, hyperreactivity, and airway remodeling. There is strong evidence that an imbalance between the reducing and oxidizing systems favoring a more oxidative state is present in asthma. Endogenous and exogenous reactive oxygen species, such as superoxide anion, hydroxyl radical, hypohalite radical, and hydrogen peroxide, and reactive nitrogen species, such as nitric oxide, peroxynitrite, and nitrite, play a major role in the airway inflammation and are determinants of asthma severity. Asthma is also associated with decreased antioxidant defenses, such as superoxide dismutase, catalase, and glutathione. In this review, we will summarize the current knowledge and discuss the current and future strategies for the modulation of oxidative stress in asthma.

[Individually-tailored treatment of chronic obstructive pulmonary disease: a proposed change]

Chronic obstructive pulmonary disease (COPD) is a highly prevalent but poorly defined disease and there is wide confusion regarding its treatment. The available knowledge should allow guidelines for specific treatment to be established according to each patient's clinical features. The present article describes a proposal for individually-tailored treatment. Long-acting bronchodilators, alone or in various combinations, would be the basis of treatment and inhaled corticosteroids (IC) should be used in a subgroup with well-defined characteristics. The latest studies indicate that the benefits of IC are limited in COPD and that the risks are not inconsiderable. Consequently, these drugs should be limited to "responders" and should always be administered in association with a long-acting beta(2) bronchodilator. The pathogenesis of this disease should be studied in greater depth and patients should be classified according to their severity, the frequency of acute exacerbations, their reversibility, comorbidity and concomitant medication in order to choose the most appropriate treatment.

Clinical efficacy of farcosolvin syrup (ambroxol-theophylline-guaiphenesin mixture) in the treatment of acute exacerbation of chronic bronchitis

BACKGROUND

Acute exacerbations of chronic bronchitis (AECB) are defined as recurrent attacks of worsening bronchial inflammation that are marked by an increase in the volume of daily sputum produced, a change in color of the expectorated sputum, and worsening dyspnea. Farcosolvin (Pharco Pharmaceuticals, Alexandria, Egypt) is a mixture of ambroxol (15 mg); theophylline (50 mg); and guaiphenesin (30 mg), per 5 mL syrup.

OBJECTIVE

To test the clinical efficacy of Farcosolvin in the treatment of AECB in a randomized, single-blinded, controlled study design.

PATIENTS AND METHODS

One hundred patients with AECB were randomized to either Farcosolvin or guaiphenesin treatment groups, in addition to the standard medical treatment for their cases. Baseline clinical symptomatolgy of breathlessness, cough, and sputum severity scoring were compared before and after 3 and 7 days of treatment in both groups and the differences compared between groups. Changes in perceived improvement were also compared between groups using the Clinical Global Impression of Improvement or Change Scale (CGIC).

RESULTS

There were statistically significant improvements in breathlessness and cough scores in both groups (pretreatment versus posttreatment at day 3 and at day 7; P < 0.05). There were highly statistically significant differences between groups in improvement in breathlessness and cough scores, after 3 and 7 days treatment, in favor of the Farcosolvin treatment group (P < 0.001). Out of 50 patients, 48 (96%) in the Farcosolvin-treated group rated their improvement on the CGIC scale as "much" and "very much" improved, while only 41 patients (82%) reported such a degree of improvement in the control group. The difference was statistically significant (P < 0.05).

CONCLUSION

We concluded from our study that Farcosolvin syrup might be safe and effective in improving symptoms in cases of acute exacerbation of chronic bronchitis.

Acute exacerbation of chronic obstructive pulmonary disease in primary care setting in Spain: the EPOCAP study

BACKGROUND

The present study was designed to describe the clinical profile of acute exacerbations of chronic obstructive pulmonary disease (COPD) and the treatment prescribed by primary care physicians (PCPs) in Spain.

METHOD

An observational, multicenter and cross-sectional study was performed in patients diagnosed with acute exacerbation of COPD and treated by PCPs. Patients diagnosed with asthma, cystic fibrosis, significant bronchiectasis or pneumonia were not included in the study.

RESULTS

A total of 329 general physicians recruited 1088 evaluable patients across the country. Mean age was 66.5+/-10.2 years; male : female ratio was 3 : 1. Spirometry was performed in 28.3% of the patients. The number of acute exacerbations in the last year was 3.3+/-2.5; 88.7% had increased expectoration, 87.5% increased dyspnea, 64.4% increased sputum purulence, and 43.5% fever. A total of 6.1% (n = 59) of patients were hospitalized due to exacerbation. The most frequently prescribed medications were antibiotics (84.5%, n = 919), mucolytic agents (72.5%, n = 789), inhaled corticosteroids (ICs) (71.3%, n = 776), and short-acting beta-adrenergic drugs (67.8%, n = 738). Oral corticosteroids were prescribed to 436 patients (40.1%).

CONCLUSIONS

The clinical profile of acute exacerbations of COPD treated in a primary care setting in Spain was characterized by shortness of breath and increased sputum production. Patients were managed by PCP mainly in outpatient clinics with antibiotics, mucolytic agents, inhaled corticosteroids, oral corticosteroids and short-acting beta-adrenergic agents. The percentage of patients with confirmed diagnosis of COPD by pulmonary function tests was very low.

Overview of novel therapeutic targets for asthma and chronic obstructive pulmonary disease

Obstructive lung diseases, in particular asthma and chronic obstructive pulmonary disease, are a worldwide health problem that is increasing in incidence. While significant progress has been made in the control of symptoms, further advances must be made in modifying the clinical situation in terms of disease progression. Numerous pathogenetic studies have demonstrated that inflammatory responses play a crucial role in the development of chronic lung obstruction, while current molecular findings have provided a myriad of new and promising therapeutic targets. The aim of this article is to provide an overview of clinically and pharmacologically relevant targets for asthma and chronic obstructive pulmonary diseases, considering currently investigated therapeutic approaches.

Oxidative stress targets in pulmonary emphysema: focus on the Nrf2 pathway

IMPORTANCE OF THE FIELD

Oxidative stress has been implicated in the pathogenesis of pulmonary emphysema. Nuclear factor erythroid-2-related factor 2 (Nrf2) a major antioxidant transcription factor could play a protective role in pulmonary emphysema.

AREAS COVERED IN THIS REVIEW

Nrf2 is ubiquitously expressed throughout the lung, but is predominantly found in epithelium and alveolar macrophages. Evidence suggests that Nrf2 and several Nrf2 downstream genes have an essential protective role in the lung against oxidative stress from environmental pollutants and toxicants such as cigarette smoke, a major causative factor for the development and progression of pulmonary emphysema. Application of Nrf2-deficient mice identified an extensive range of protective roles for Nrf2 against the pathogenesis of pulmonary emphysema. Therefore, Nrf2 promises to be an attractive therapeutic target for intervention and prevention strategies.

WHAT THE READER WILL GAIN

In this review, we discuss recent findings on the association of oxidative stress with pulmonary emphysema. We also address the mechanisms of Nrf2 lung protection against oxidative stress based on emerging evidence from experimental oxidative disease models and human studie.

TAKE HOME MESSAGE

The current literature suggests that among oxidative stress targets, Nrf2 is a valuable therapeutic target in pulmonary emphysema.

Mucolytic agents for chronic bronchitis or chronic obstructive pulmonary disease

BACKGROUND

Individuals with chronic bronchitis or chronic obstructive pulmonary disease (COPD) may suffer recurrent exacerbations with an increase in volume and/or purulence of sputum. Because of the personal and healthcare costs associated with exacerbations, any therapy that reduces the number of exacerbations is useful. There is a marked difference between countries in terms of prescribing of mucolytics depending on whether or not they are perceived to be effective.

OBJECTIVES

To assess the effects of oral mucolytics in adults with stable chronic bronchitis or COPD.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register and reference lists of articles on eight separate occasions, the most recent being in September 2008.

SELECTION CRITERIA

Randomised trials that compared oral mucolytic therapy with placebo for at least two months in adults with chronic bronchitis or COPD. We excluded studies of people with asthma and cystic fibrosis.

DATA COLLECTION AND ANALYSIS

One review author extracted data. We contacted study authors and drug companies for missing information.

MAIN RESULTS

Twenty-eight trials involving 7042 participants were included. Compared with placebo, there was a significant reduction in the number of exacerbations per patient with oral mucolytics (weighted mean difference (WMD) -0.04 per month, 95% confidence interval -0.05 to -0.03). Using a weighted annualised rate of exacerbations in the control patients of 2.4 per year, this is a 21% reduction. The number of days of disability also fell (WMD -0.56, 95% confidence interval (CI) -0.77 to -0.35). One recent study has shown that the benefit may apply only to patients not already receiving inhaled corticosteroids. The number of patients who remained exacerbation-free was greater in the mucolytic group (odds ratio (OR) 1.93 (95% CI 1.71 to 2.17)). There is no strong evidence of improvement in lung function and treatment is not associated with any increase in adverse effects. Patients on mucolytics may be less likely to be hospitalised during the study period.

AUTHORS' CONCLUSIONS

In participants with chronic bronchitis or COPD, treatment with mucolytics was associated with a small reduction in acute exacerbations and a reduction in total number of days of disability. Benefit may be greater in individuals who have frequent or prolonged exacerbations, or those who are repeatedly admitted to hospital with exacerbations with COPD. Mucolytics should be considered for use, through the winter months at least, in patients with moderate or severe COPD in whom inhaled corticosteroids (ICS) are not prescribed.

Anti-inflammatory effects of Myrtol standardized and other essential oils on alveolar macrophages from patients with chronic obstructive pulmonary disease

INTRODUCTION

Myrtol standardized is established in the treatment of acute and chronic bronchitis and sinusitis. It increases mucociliar clearance and has muco-secretolytic effects. Additional anti-inflammatory and antioxidative properties have been confirmed for Myrtol standardized, eucalyptus oil, and orange oil in several in vitro studies.

OBJECTIVE

The aim of this study was to prove the ability of essential oils to reduce cytokines release and reactive oxygen species (ROS) production derived from ex vivo cultured alveolar macrophages.

MATERIAL AND METHODS

Alveolar macrophages from patients with chronic obstructive pulmonary disease (COPD, n=26, GOLD III-IV) were pre-cultured with essential oils (10(3)-10(-8)%) for 1 h and then stimulated with LPS (1 microg/ml). After 4 h and 20 h respectively a) cellular reactive oxygen species (ROS) using 2',7'-dichlorofluorescein (DCF), and b) TNF-alpha, IL-8, and GM-CSF secretion were quantified.

RESULTS

In comparison with negative controls, pre-cultured Myrtol, eucalyptus oil and orange oil (10-4%) reduced in the LPS-activated alveolar macrophages ROS release significantly after 1+20 h as follows: Myrtol -17.7% (P=0.05), eucalyptus oil -21.8% (P<0.01) and orange oil -23.6% (P<0.01). Anti-oxidative efficacy was comparable to NAC (1 mmol/l). Essential oils also induced a TNF-alpha reduction: Myrtol (-37.3%, P<0.001), eucalyptus oil (-26.8%, P<0.01) and orange oil (-26.6%, P<0.01). TNF-a reduction at 1+4 h and 1+20 h did not vary (Myrtol: -31.9% and -37.3% respectively, P= 0.372) indicating that this effect occurs early and cannot be further stimulated. Myrtol reduced the release of GM-CSF by -35.7% and that of IL-8 only inconsiderably.

CONCLUSIONS

All essential oils tested have effective antioxidative properties in ex vivo cultured and LPS-stimulated alveolar macrophages. Additionally, Myrtol inhibited TNF-a and GM-CSF release best indicating additional potent anti-inflammatory activity.

Management of chronic obstructive pulmonary disease: moving beyond the asthma algorithm

For many years, chronic obstructive pulmonary disease (COPD) was considered a disease of fixed airflow obstruction for which there was no good treatment. Out of desperation and frustration, health care providers extrapolated from asthma to COPD, and standard asthma therapy was adopted without evidence for efficacy. In recent years, we have gained a better understanding of the pathophysiologic differences between asthma and COPD, and prospective controlled trials have provided a rationale for therapy. Smoking cessation is critically important, both as primary prevention and as an effective way to slow the decrease in lung function in patients with established disease. beta(2)-Adrenergic and anticholinergic agonists improve lung function and relieve symptoms in most patients. Tiotropium improves exercise tolerance and quality of life and reduces exacerbations and hospitalizations. The increase in lung function seen with tiotropium is sustained with continued use over at least 3 to 4 years. Inhaled corticosteroids decrease exacerbations and improve quality of life, and their effect seems greatest in patients with lower lung function and in exacerbation-prone patients. There is no evidence that inhaled corticosteroids alone affect mortality, despite the reduction in exacerbations and increased risk of pneumonia. In some patient populations, inhaled fluticasone, salmeterol, or the combination might slow the rate of loss of lung function. Rather than reflexively using effective asthma therapy in the patient with COPD, current and future therapy for COPD is increasingly evidence based and targeted to specific inflammatory pathways that are important in patients with COPD.

Targeted treatment in COPD: a multi-system approach for a multi-system disease

Chronic obstructive pulmonary disease is a varied condition when examined from a number of different perspectives including factors which influence disease development, pathological process and clinical features. There may be a complex interaction between the degree by which each of these processes influences the development of COPD and the subsequent clinical phenotype with which the patient presents. The varied host response and subsequent clinical phenotype has generated much interest in recent years. It is possible that failure of treatment to impact on mortality and reverse the disease process is because of the heterogeneous nature of the condition. Identification and targeted treatment of clinical and pathological phenotypes within the broad spectrum of COPD may therefore improve outcome. This article will review previous work which has attempted to phenotype COPD and identify if specific treatment for these phenotypes has been shown to be of benefit. It will examine the work on pathological processes and clinical manifestations, both pulmonary and systemic, and will focus on pharmacological therapies.