Prevention by ambroxol of bronchopulmonary complications after upper abdominal surgery: double-blind Italian multicenter clinical study versus placebo

Comparison of Clinical Effectiveness Between Ambroxol and N-Acetylcysteine in Surgical Patients: A Retrospective Cohort Study

Postoperative pulmonary complications (PPCs) are a major cause of postoperative morbidity, mortality, and longer hospital stays. Expectorants are widely used during the perioperative period to reduce PPCs. This study aimed to compare the clinical effectiveness between ambroxol (AMB) and N-acetylcysteine (NAC) in patients undergoing surgery. A multicenter, retrospective cohort study was conducted using deidentified medical records from hospital information system. Between July 1, 2015, and November 30, 2017, patients aged ≥18 years, who received intravenous AMB or nebulized NAC as the only expectorant therapy for >3 days during their hospitalization for thoracic, abdominal, and neurosurgery, were included in this study. The clinical outcomes were evaluated, and propensity score matching was used to adjust significant differences between 2 groups. A total of 4025 cases in the AMB group and 2062 in NAC group after propensity score matching were identified. The incidence of PPCs (13.9% vs 11.6%; P = .013), postoperative sputum suction (17.2% vs 8.0%; P < .001), intensive care unit admission after surgery (25.1% vs 22.5%; P = .024), and postoperative mechanical ventilation (22.3% versus 17.5%; P < .001) in the AMB group were all significantly higher than those in the NAC group. This study suggested that patients treated with NAC during the perioperative period had a significantly lower risk of PPCs. However, further prospective study is needed to ensure the replicability of our findings.

Perioperative Pulmonary Atelectasis: Part II. Clinical Implications

The development of pulmonary atelectasis is common in the surgical patient. Pulmonary atelectasis can cause various degrees of gas exchange and respiratory mechanics impairment during and after surgery. In its most serious presentations, lung collapse could contribute to postoperative respiratory insufficiency, pneumonia, and worse overall clinical outcomes. A specific risk assessment is critical to allow clinicians to optimally choose the anesthetic technique, prepare appropriate monitoring, adapt the perioperative plan, and ensure the patient's safety. Bedside diagnosis and management have benefited from recent imaging advancements such as lung ultrasound and electrical impedance tomography, and monitoring such as esophageal manometry. Therapeutic management includes a broad range of interventions aimed at promoting lung recruitment. During general anesthesia, these strategies have consistently demonstrated their effectiveness in improving intraoperative oxygenation and respiratory compliance. Yet these same intraoperative strategies may fail to affect additional postoperative pulmonary outcomes. Specific attention to the postoperative period may be key for such outcome impact of lung expansion. Interventions such as noninvasive positive pressure ventilatory support may be beneficial in specific patients at high risk for pulmonary atelectasis (e.g., obese) or those with clinical presentations consistent with lung collapse (e.g., postoperative hypoxemia after abdominal and cardiothoracic surgeries). Preoperative interventions may open new opportunities to minimize perioperative lung collapse and prevent pulmonary complications. Knowledge of pathophysiologic mechanisms of atelectasis and their consequences in the healthy and diseased lung should provide the basis for current practice and help to stratify and match the intensity of selected interventions to clinical conditions.

Perioperative interventions for prevention of postoperative pulmonary complications: systematic review and meta-analysis

OBJECTIVE

To identify, appraise, and synthesise the best available evidence on the efficacy of perioperative interventions to reduce postoperative pulmonary complications (PPCs) in adult patients undergoing non-cardiac surgery.

DESIGN

Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES

Medline, Embase, CINHAL, and CENTRAL from January 1990 to December 2017.

ELIGIBILITY CRITERIA

Randomised controlled trials investigating short term, protocolised medical interventions conducted before, during, or after non-cardiac surgery were included. Trials with clinical diagnostic criteria for PPC outcomes were included. Studies of surgical technique or physiological or biochemical outcomes were excluded.

DATA EXTRACTION AND SYNTHESIS

Reviewers independently identified studies, extracted data, and assessed the quality of evidence. Meta-analyses were conducted to calculate risk ratios with 95% confidence intervals. Quality of evidence was summarised in accordance with GRADE methods. The primary outcome was the incidence of PPCs. Secondary outcomes were respiratory infection, atelectasis, length of hospital stay, and mortality. Trial sequential analysis was used to investigate the reliability and conclusiveness of available evidence. Adverse effects of interventions were not measured or compared.

RESULTS

117 trials enrolled 21 940 participants, investigating 11 categories of intervention. 95 randomised controlled trials enrolling 18 062 participants were included in meta-analysis; 22 trials were excluded from meta-analysis because the interventions were not sufficiently similar to be pooled. No high quality evidence was found for interventions to reduce the primary outcome (incidence of PPCs). Seven interventions had low or moderate quality evidence with confidence intervals indicating a probable reduction in PPCs: enhanced recovery pathways (risk ratio 0.35, 95% confidence interval 0.21 to 0.58), prophylactic mucolytics (0.40, 0.23 to 0.67), postoperative continuous positive airway pressure ventilation (0.49, 0.24 to 0.99), lung protective intraoperative ventilation (0.52, 0.30 to 0.88), prophylactic respiratory physiotherapy (0.55, 0.32 to 0.93), epidural analgesia (0.77, 0.65 to 0.92), and goal directed haemodynamic therapy (0.87, 0.77 to 0.98). Moderate quality evidence showed no benefit for incentive spirometry in preventing PPCs. Trial sequential analysis adjustment confidently supported a relative risk reduction of 25% in PPCs for prophylactic respiratory physiotherapy, epidural analgesia, enhanced recovery pathways, and goal directed haemodynamic therapies. Insufficient data were available to support or refute equivalent relative risk reductions for other interventions.

CONCLUSIONS

Predominantly low quality evidence favours multiple perioperative PPC reduction strategies. Clinicians may choose to reassess their perioperative care pathways, but the results indicate that new trials with a low risk of bias are needed to obtain conclusive evidence of efficacy for many of these interventions.

STUDY REGISTRATION

Prospero CRD42016035662.

Value of ambroxol in the treatment of asthmatic bronchitis

OBJECTIVE

To investigate the clinical effect of ambroxol in the treatment of asthmatic bronchitis.

METHODS

One hundred and twenty patients with asthmatic bronchitis who were admitted to our hospital from June 2017 to August 2018 were selected as the research subjects and divided into a control group and an observation group according to random number table method, 60 in each group. The control group was treated with conventional treatment, while the observation group was treated with ambroxol in addition to conventional treatment. The therapeutic effect, disappearance time of symptoms and signs and the recovery of pulmonary function were compared between the two groups.

RESULTS

The total effective rate of the observation group was 96.7%, and that of the control group was 73.3%. The control effect of the observation group was significantly better than that of the control group, showing a significant difference (P<0.05). The disappearance time of symptoms of the observation group was shorter than that of the control group, and the recovery of pulmonary function was better; the differences were statistically significant (P<0.05).

CONCLUSION

For asthmatic bronchitis patients, addition of ambroxol to conventional treatment can improve the therapeutic effect, shorten the disappearance time of clinical signs and symptoms, and promote the recovery of patients, which is worth clinical application.

Does ambroxol confer a protective effect on the lungs in patients undergoing cardiac surgery or having lung resection?

A best evidence topic in perioperative care was written according to a structured protocol. The question addressed was 'Does ambroxol confer a protective effect on the lung in patients undergoing cardiac surgery or having lung resection?' A total of 247 papers were found using the reported search, of which 7 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. Several studies indicate that for patients with chronic obstructive pulmonary disease (COPD) who undergo cardiac surgery or upper abdominal surgery, perioperative ambroxol administration is associated with improved pulmonary function and reduced postoperative pulmonary complications (PPCs). In patients with pulmonary lobectomy, large-dose ambroxol treatment (1000 mg/day for 3 days) is correlated with reduced PPCs (6 vs 19%, P = 0.02), decreased postoperative hospital stay (5.6 vs 8.1 days, P = 0.02) and lower postoperative cost (2499 vs 5254 €, P = 0.04) compared with low-dose ambroxol treatment. Ambroxol also has a protective effect on the lungs during extracorporeal bypass, ameliorating inflammatory reaction and oxygen stress and preserving pulmonary surfactant. However, there is no evidence for any advantage of reducing PPCs after extracorporeal circulation. We conclude that perioperative application of ambroxol, a versatile mucoactive drug, particularly in high doses, is associated with lower PPCs, especially in high-risk patients with fundamental lung disease such as COPD. Large doses of ambroxol are correlated with even lower PPCs after lung resection. We recommend that routine intravenous ambroxol should be used in large doses in high-risk patients in the perioperative period to reduce the risk of PPCs.

Biofilm-dependent airway infections: a role for ambroxol?

Biofilms are a key factor in the development of both acute and chronic airway infections. Their relevance is well established in ventilator associated pneumonia, one of the most severe complications in critically ill patients, and in cystic fibrosis, the most common lethal genetic disease in Caucasians. Accumulating evidence suggests that biofilms could have also a role in chronic obstructive pulmonary disease and their involvement in bronchiectasis has been proposed as well. When they grow in biofilms, microorganisms become multidrug-resistant. Therefore the treatment of biofilm-dependent airway infections is problematic. Indeed, it still largely based on measures aiming to prevent the formation of biofilms or remove them once that they are formed. Here we review recent evidence suggesting that the mucokinetic drug ambroxol has specific anti-biofilm properties. We also discuss how additional pharmacological properties of this drug could be beneficial in biofilm-dependent airway infections. Specifically, we review the evidence showing that: 1-ambroxol exerts anti-inflammatory effects by inhibiting at multiple levels the activity of neutrophils, and 2-it improves mucociliary clearance by interfering with the activity of airway epithelium ion channels and transporters including sodium/bicarbonate and sodium/potassium/chloride cotransporters, cystic fibrosis transmembrane conductance regulator and aquaporins. As a whole, the data that we review here suggest that ambroxol could be helpful in biofilm-dependent airway infections. However, considering the limited clinical evidence available up to date, further clinical studies are required to support the use of ambroxol in these diseases.

Ambroxol: a multifaceted molecule with additional therapeutic potentials in respiratory disorders of childhood

INTRODUCTION

Mucoactive drugs are currently used to cleanse the respiratory tract following disturbance of the normal mucociliary clearance due to mucous hyperproduction and/or modification of its physicochemical characteristics. However, in addition to possessing the ability to perform specific actions on airway secretion, these compounds have the capability to modulate the mechanisms involved in abnormal secretions. Indeed, over the years, in the postmarketing phase, a large number of studies have been published showing interesting pharmacological activities in addition to their secretagogue activity.

AREAS COVERED

This article collates available data on ambroxol (2-amino-3,5-dibromo-N-[trans-4-hydroxycyclohexyl]benzylamine), a metabolite of bromhexine, used as a secretagogue in the treatment of childhood airway diseases. This article goes beyond the mucoactive aspects of the drug covering its multiple pharmacological properties.

EXPERT OPINION

The non-mucoactive functions exhibited by the compound may provide beneficial effects on airway structure and function in health and disease. Beyond the mucokinetic and secretagogue effects, ambroxol showed great antioxidant, anti-inflammatory, local anesthetic and surfactant synthesis stimulatory activities. Moreover, some antiviral and antibacterial activities were shown. These findings may better explain the clinical results observed in a variety of airway disorders and suggest additional therapeutic potential. Further studies are needed to better define the clinical relevance of these non-mucolytic activities.

Differential modulation of IgE-dependent activation of human basophils by ambroxol and related secretolytic analogues

Ambroxol is a widely used secretolytic agent originally developed from vasicine, a natural alkaloid found in Adhatoda vasica, extracts of which have been used to treat bronchitis, asthma, and rheumatism. We previously reported that ambroxol inhibits IgE-dependent mediator secretion from human mast cells and basophils, key effector cells of allergic inflammation. Here, the mechanisms involved in the inhibitory properties of ambroxol were assessed in comparison to other secretolytic analogues (e.g. vasicine, bromhexine, sputolysin). The results show that, in comparison to ambroxol, which reduced IgE-dependent histamine release from basophils at 10 microM-1 mM, the release of the amine was only moderately reduced by sputolysin and vasicine at 1 mM. In contrast, above 10 microM, bromhexine was found to be toxic to basophils in vitro as evidenced by induction of histamine release and reduced cell viability. In contrast, the inhibitory actions of ambroxol at concentrations below 1 mM were not toxic and entirely reversible. Ambroxol was also more potent than either sputolysin or vasicine in attenuating basophil IL-4 and IL-13 secretions, whereas bromhexine-induced suppression of de novo cytokine synthesis was due to toxic effects. Additionally, ambroxol reduced IgE-dependent p38 MAPK phosphorylation in basophils, unlike bromhexine, sputolysin and vasicine. These results clearly show that ambroxol is both more potent and effective at inhibiting IgE-dependent basophil mediator release and p38 MAPK activity than the other secretolytic analogues employed. The therapeutic potential of ambroxol as an anti-allergic agent is further underlined by these data.

Ambroxol in the 21st century: pharmacological and clinical update

BACKGROUND

Belonging to the group of expectorants, ambroxol is an active substance with a long history that influences parameters considered to be the basis for the physiological production and the transport of the bronchial mucus. Therefore, ambroxol's indication is 'secretolytic therapy in acute and chronic bronchopulmonary diseases associated with abnormal mucus secretion and impaired mucus transport'.

OBJECTIVE

The aim of this review is to evaluate the pharmacological and clinical data on the mucokinetic compound ambroxol.

METHODS

The existing database that covers >40 years of pharmacological research and clinical development was analysed. Only studies with adequate study design were evaluated.

CONCLUSION

Ambroxol is shown to exert several activities: i) secretolytic activity (i.e., promotes mucus clearance, facilitates expectoration, and eases productive cough); ii) anti-inflammatory and antioxidant activity; and iii) a local anaesthetic effect through sodium channel blocking at the level of the cell membrane. The reduction on chronic obstructive pulmonary disease exacerbations is consistent and clinically relevant. The anaesthetic effect is a new pharmacological action that could be beneficial in the management of acute respiratory tract infections. The efficacy and safety of ambroxol is well established.

Management of chronic obstructive pulmonary disease in the elderly

Chronic obstructive pulmonary disease (COPD), a leading cause of death and disability in the elderly, is frequently unrecognized or misinterpreted as heart disease. Comorbidity plays a primary role, both as a determinant of health status and as a prognostic marker in older populations with COPD. Multidimensional assessment tailored to the distinctive needs of respiratory patients and thus including selected respiratory function indexes, is mandatory for proper staging COPD and monitoring of its course and response to therapy. In stable COPD, a mix of pharmacological and non-pharmacological measures may improve health, but only by stopping smoking and, in the event of respiratory insufficiency, applying continuous oxygen therapy can the progression of the disease be delayed and life expectancy prolonged. In exacerbated COPD, age per se is a negative prognostic marker and, while many very old patients can successfully recover, they will experience some decline in personal independence. Thus, older patients with COPD should ideally be the object of a continuum of care throughout all the stages of their disease, in order to minimize the decline in personal independence and worsening health. In this perspective, COPD patients qualify as optimal candidates for dedicated programs of continuous geriatric care.

Inhibition of bleomycin-induced cell death in rat alveolar macrophages and human lung epithelial cells by ambroxol

The mitochondrial permeability transition is recognized to be involved in toxic and oxidative forms of cell injury. In the present study, we investigated the effect of ambroxol against the cytotoxicity of bleomycin (BLM) by looking at the effect on the mitochondrial membrane permeability in alveolar macrophages and lung epithelial cells. Alveolar macrophages or lung epithelial cells exposed to BLM revealed the loss of cell viability and increase in caspase-3 activity. Ambroxol (10-100 microM) reduced the 75 mU/mL BLM-induced cell death and activation of caspase-3 in macrophages or epithelial cells. It reduced the condensation and fragmentation of nuclei caused by BLM in macrophages. Ambroxol alone did not significantly cause cell death. Treatment of alveolar macrophages with BLM resulted in the decrease in transmembrane potential in mitochondria, cytosolic accumulation of cytochrome c, increase in formation of reactive oxygen species (ROS) and depletion of GSH. Ambroxol (10-100 microM) inhibited the increase in mitochondrial membrane permeability, ROS formation and decrease in GSH contents due to BLM in macrophages. Ambroxol exerted a scavenging effect on hydroxyl radicals and nitric oxide and reduced the iron-mediated formation of malondialdehyde and carbonyls in liver mitochondria. It prevented cell death due to SIN-1 in lung epithelial cells. The results demonstrate that ambroxol attenuates the BLM-induced viability loss in alveolar macrophages or lung epithelial cells. This effect may be due to inhibition of mitochondrial damage and due to the scavenging action on free radicals.

Ambroxol inhibits peroxynitrite-induced damage of alpha1-antiproteinase and free radical production in activated phagocytic cells

The present study examined the effect of ambroxol on toxic action of peroxynitrite and the respiratory burst in activated phagocytic cells. Ambroxol decreased the inactivation or destruction of alpha1-antiproteinase induced by peroxynitrite (ONOO-) or hypochlorous acid (HOCl), which was similar to penicillamine and glutathione and was greater than diclofenac sodium and naproxen sodium. Ambroxol significantly decreased ONOO--mediated tyrosine nitration and iron plus EDTA-mediated degradation of 2-deoxy-D-ribose. Ambroxol significantly attenuated the production of superoxide, hydrogen peroxide, HOCl, and nitric oxide in fMLP- or IL-1-activated phagocytic cells, while the inhibitory effects of antiinflammatory and thiol compounds were only observed in HOCl production. Ambroxol and antiinflammatory drugs did not show a cytotoxic effect on macrophages. The results suggest that ambroxol protects tissue components against oxidative damage by an action different from antiinflammatory drugs. Ambroxol may interfere with oxidative damage of alpha1-antiproteinase through a scavenging action on ONOO- and HOCl and inhibition of the respiratory burst of phagocytic cells.

Depressant effect of ambroxol on stimulated functional responses and cell death in rat alveolar macrophages exposed to silica in vitro

The present study examined the effect of ambroxol on free radical production, granule enzyme release, and cell death in silica-activated rat alveolar macrophages. The action of ambroxol was assayed by measuring changes in the activities of protein kinase C (PKC) and tyrosine kinase (PTK) and in the intracellular calcium level. Ambroxol attenuated the production of superoxide, hydrogen peroxide, and nitric oxide and the release of acid phosphatase and lysozyme in macrophages activated by silica. Staurosporine, genistein, EGTA, and trifluoperazine inhibited the silica-induced free radical production and granule enzyme release. Silica induced the increase in PKC and PTK activities and the elevation of intracellular calcium level in macrophages, which was decreased by ambroxol. Silica induced a cell death and increased the caspase-3 activity in macrophages in a concentration-dependent manner. Ambroxol decreased the silica-induced cell viability loss in macrophages. The results show that ambroxol decreases the stimulated responses and cell death in rat alveolar macrophages exposed to silica, which may be accomplished by inhibition of activation processes, protein kinases, and calcium transport. The inhibitory effect of ambroxol on silica-induced cell death appears to provide the protective effect on pulmonary tissues against the toxic action of silica.

Depressant effects of ambroxol on lipopolysaccharide- or fMLP-stimulated free radical production and granule enzyme release by alveolar macrophages

In order to explore the depressant action of ambroxol, a bronchial expectorant, on the activated alveolar macrophage responses, its effect on lipopolysaccharide (LPS)- or N-formyl-methionyl-leucyl-phenylalanine (fMLP)- stimulated free radical production and granule enzyme release by rat lung alveolar macrophages was investigated. Ambroxol attenuated the 100 ng/ml LPS- or 1 microM fMLP-stimulated superoxide, H(2)O(2)and nitric oxide production and releases of acid phosphatase and lysozyme by alveolar macrophages. Ambroxol attenuated phorbol myristate acetate-stimulated superoxide and nitric oxide production that was inhibited by 100 nM staurosporine. N,N-dimethylsphingosine (DMS, 4.5 and 9 microM) alone stimulated superoxide production by macrophages, while 45 microM of the compound did not show a stimulatory effect. However, DMS decreased nitric oxide production in a dose-dependent manner. Ambroxol did not alter the DMS effect on free radical production that was affected by 10 microM genistein. A preincubation of macrophages with ambroxol (10 and 100 microM), staurosporine and genistein attenuated the elevation of [Ca(2+)](i)caused by LPS. The results suggest that ambroxol exerts a depressant effect on LPS- or fMLP-stimulated free radical production and granule enzyme release by rat alveolar macrophages, which may be attributed to its inhibitory action on the activation process, protein kinase C, but its action on protein tyrosine kinase is not suggested.

The inhibitory effect of ambroxol on hypochlorous acid-induced tissue damage and respiratory burst of phagocytic cells

Ambroxol (100 microM and 1 mM) and the thiols (all 1 mM), glutathione, tiopronin and cysteine, significantly attenuated the myeloperoxidase, H(2)O(2) and Cl(-) system-caused destruction of alpha(1)-antiproteinase and the HOCl-induced destruction of collagen, whereas they did not affect the elastase-induced destruction of collagen. Glutathione, tiopronin and cysteine almost completely decomposed both HOCl and H(2)O(2), while ambroxol up to 1 mM did not show a scavenging action on H(2)O(2). Ambroxol (1 to 100 microM) and 1 mM thiol compounds markedly inhibited the HOCl-induced alteration of elastase activity. Thiol compounds significantly attenuated the HOCl production caused by degraded immunoglobulin G-activated neutrophils. Ambroxol depressed superoxide and H(2)O(2) production induced by degraded immunoglobulin G-activated neutrophils and by lipopolysaccharide-activated alveolar macrophages in a dose-dependent manner. The results show that ambroxol may interfere with oxidative tissue damage and decrease proteolytic tissue destruction by attenuation of oxidative stress-induced inactivation of alpha(1)-antiproteinase through both decomposition of HOCl and inhibition of the respiratory burst in phagocytic cells.

The inhibitory effect of ambroxol on respiratory burst, degranulation and cytosolic Ca2+ change in degraded immunoglobulin G-activated neutrophils

Superoxide and H2O2 production by neutrophils stimulated by 0.5 mg/ml degraded immunoglobulin G (IgG) and 1 microM N-formyl-methionyl-leucyl-phenylalanine (fMLP) was inhibited by ambroxol in a dose-dependent fashion, and at the concentration of 100 microM, 43.3% to 64.3% of inhibitions were detected. The inhibitory effect of ambroxol on H2O2 production by neutrophils was greater than that on superoxide production. The production of nitrite by lipopolysaccharide-activated murine peritoneal macrophages was significantly attenuated by ambroxol in a dose-dependent fashion and NG-monomethyl-L-arginine (NMMA). Ambroxol decreased the release of myeloperoxidase and lysozyme evoked by 0.5 mg/ml degraded immunoglobulin G and 1 microM fMLP in a dose-dependent fashion, and at the concentration of 100 microM, 37.1% to 64.2% of inhibitions were observed. The stimulatory effect of phorbol 12-myristate 13-acetate (PMA) (0.1 microg/ml) on superoxide production and myeloperoxidase, which is inhibited by 100 nM staurosporine, was not affected by 100 microM ambroxol. Degraded immunoglobulin G (0.5 mg/ml) caused an immediate elevation of [Ca2+]i in fura-2 load neutrophils in 1.23 mM Ca2+-containing medium. Preincubation of neutrophils with 10 microM to 100 microM ambroxol, 5 mM EGTA and 100 microM verapamil depressed the elevation of [Ca2+]i elicited by 0.5 mg/ml degraded immunoglobulin G. In conclusion, the inhibitory action of ambroxol on stimulated neutrophil responses, including respiratory burst and lysosomal enzyme release, appears to be attributed to its depressant action on the activation process, including the change in intracellular Ca2+ level. in which the role of protein kinase C is uncertain.

Effect of ambroxol on oxygen radical production and generation by bronchoalveolar lavage cells in young and aged guinea pigs

We examined the effect of ambroxol and age on oxygen radical production and generation with stimulation of phorbol-myristate acetate (PMA) by bronchoalveolar lavage (BAL) cells. Lung free cells including pulmonary alveolar macrophages were harvested from young (4-month-old) and aged (28-month-old) male guinea pigs using BAL. The oxygen radicals produced by BAL cells with or without stimulation of PMA were measured by the lucigenin-dependent chemiluminescence method using a photon counter. Oxygen radical production and generation by BAL cells were not different between young and aged guinea pigs. However, the oxygen radical generation after stimulation with PMA was greater than the oxygen radical spontaneous production both in young and aged animals. Ambroxol solution given into culture media containing BAL cells inhibited oxygen radical production and generation by BAL cells harvested from both young and aged guinea pigs in a concentration-dependent manner. Approximately 16-20 microM of ambroxol inhibited 50% of the production of oxygen radicals in vitro by BAL cells in young and aged guinea pigs, whereas a slightly greater amount of ambroxol was necessary to inhibit 50% of the PMA-induced oxygen radical generation in vitro by BAL cells in guinea pigs. These results indicate that ambroxol inhibits oxygen radicals produced by BAL cells from young and aged guinea pigs, and they suggest that ambroxol may be a possible therapeutic modality for ameliorating oxidant associated pulmonary disorders in young and aged patients.

Characterization of N-acetylcysteine and ambroxol in anti-oxidant therapy

Reactive free oxygen radicals are known to play an important role in the pathogenesis of various lung diseases such as idiopathic pulmonary fibrosis (IPF), adult respiratory distress syndrome (ARDS) or cystic fibrosis (CF). They can originate from endogenous processes or can be part of exogenous exposures (e.g. ozone, cigarette smoke, asbestos fibres). Consequently, therapeutic enhancement of anti-oxidant defence mechanisms in these lung disorders seems a rational approach. In this regard, N-acetyl-L-cysteine (NAC) and ambroxol have both been frequently investigated. Because of its SH group, NAC scavenges H2O2 (hydrogen peroxide), .OH (hydroxol radical), and HOCl (hypochlorous acid). Furthermore, NAC can easily be deacetylated to cysteine, an important precursor of cellular glutathione synthesis, and thus stimulate the cellular glutathione system. This is most evident in pulmonary diseases characterized by low glutathione levels and high oxidant production by inflammatory cells (e.g. in IPF and ARDS). NAC is an effective drug in the treatment of paracetamol intoxication and may even be protective against side-effects of mutagenic agents. In addition NAC reduces cellular production of pro-inflammatory mediators (e.g. TNF-alpha, IL-1). Also, ambroxol [trans-4-(2-amino-3,5-dibromobenzylamino)-cyclohexane hydrochloride] scavenges oxidants (e.g. .OH, HOCl). Moreover, ambroxol reduces bronchial hyperreactivity, and it is known to stimulate cellular surfactant production. In addition, ambroxol has anti-inflammatory properties owing to its inhibitory effect on the production of cellular cytokines and arachidonic acid metabolites. For both substances effective anti-oxidant and anti-inflammatory function has been validated when used in micromolar concentrations. These levels are attainable in vivo in humans. This paper gives an up-to-date overview about the current knowledge of the hypothesis that oxidant-induced cellular damage underlies the pathogenesis of many human pulmonary diseases, and it discusses the feasibility of anti-oxidant augmentation therapy to the lung by using NAC or ambroxol.

Oxidant scavenger function of ambroxol in vitro: a comparison with N-acetylcysteine

Highly reactive oxygen metabolites play an important role in inflammatory processes in the lung. Ambroxol (2-amino-3,5-dibromo-N-[trans-4- hydroxycyclohexyl]benzylamine) has been shown to reduce oxidant-mediated cell damage. However, the mechanism of this effect remains unclear. In order to evaluate oxidant scavenger function increasing concentrations of ambroxol (0-10(-3) mol/l) were compared with equimolar concentrations of N-acetylcysteine (NAC) and glutathione (GSH) in vitro to reduce OH. (hydroxyl radical), HOC1 (hypochlorous acid), O-2 (superoxide anion) and H2O2 (hydrogen peroxide). OH. was measured spectrophotometrically (deoxyribose assay); O-2 (xanthine/x-oxidase), H2O2 and HOC1 (HOC1/OC1-) were determined by chemiluminescence. Ambroxol, NAC and reduced GSH scavenged OH. significantly at 10(-3) mol/l, while HOC1 was inhibited at concentrations > or = 10(-4) mol/l completely (P < 0.01). NAC and GSH had no anti-O-2 function, while ambroxol (10(-4) mol/l) reduced O-2 by 14.3 +/- 6.7%. In contrast, GSH and NAC scavenged H2O2 at > 10(-6) mol/l (P < 0.01), while ambroxol had no anti-H2O2 effect. Our data demonstrate direct oxidant-reducing capabilities of ambroxol, which may be directly related to the aromatic moiety of the molecule. However, high concentrations (micromolar concentrations) are needed. Due to differences in direct oxidant scavenger function, a combination of ambroxol and NAC could be beneficial in antioxidant therapy.

Stacked inspiratory spirometry reduces pulmonary shunt in patients after coronary artery bypass

Atelectasis is a major factor in postoperative morbidity for patients undergoing cardiopulmonary surgery. We evaluated the effectiveness of stacked inspiratory spirometry (STIS) in 17 patients status postcoronary artery bypass graft in a nonrandomized fashion. We measured pulmonary shunt as an endpoint, and compared the magnitudes before and after the STIS maneuver. Our results showed an 8.66 percent reduction in pulmonary shunt (p < 0.05). The reduction in shunt was modest; however, repetitive maneuvers might result in greater improvement.