Effects of erdosteine on bleomycin-induced lung fibrosis in rats

Use of thiols and implications for the use of inhaled corticosteroids in the presence of oxidative stress in COPD

BACKGROUND

Oxidative stress and persistent airway inflammation are thought to be important contributors to the development of chronic obstructive pulmonary disease (COPD). This review summarizes the evidence for targeting oxidative stress and inflammation in patients with COPD with mucolytic/antioxidant thiols and inhaled corticosteroids (ICS), either alone or in combination.

MAIN BODY

Oxidative stress is increased in COPD, particularly during acute exacerbations. It can be triggered by oxidant air pollutants and cigarette smoke and/or by endogenous reactive oxygen species (ROS) released from mitochondria and activated inflammatory, immune and epithelial cells in the airways, together with a reduction in endogenous antioxidants such as glutathione (GSH). Oxidative stress also drives chronic inflammation and disease progression in the airways by activating intracellular signalling pathways and the release of further inflammatory mediators. ICS are anti-inflammatory agents currently recommended for use with long-acting bronchodilators to prevent exacerbations in patients with moderate-to-severe COPD, especially those with eosinophilic airway inflammation. However, corticosteroids can also increase oxidative stress, which may in turn reduce corticosteroid sensitivity in patients by several mechanisms. Thiol-based agents such as erdosteine, N-acetyl L-cysteine (NAC) and S-carboxymethylcysteine (S-CMC) are mucolytic agents that also act as antioxidants. These agents may reduce oxidative stress directly through the free sulfhydryl groups, serving as a source of reducing equivalents and indirectly though intracellular GSH replenishment. Few studies have compared the effects of corticosteroids and thiol agents on oxidative stress, but there is some evidence for greater antioxidant effects when they are administered together. The current Global Initiative for Chronic Obstructive Lung Disease (GOLD) report supports treatment with antioxidants (erdosteine, NAC, S-CMC) in addition to standard-of-care therapy as they have been demonstrated to reduce COPD exacerbations. However, such studies have demonstrated that NAC and S-CMC reduced the exacerbation risk only in patients not treated with ICS, whereas erdosteine reduced COPD exacerbations irrespective of concomitant ICS use suggesting that erdosteine has additional pharmacological actions to ICS.

CONCLUSIONS

Further clinical trials of antioxidant agents with and without ICS are needed to better understand the place of thiol-based drugs in the treatment of patients with COPD.

The protective effects of erdosteine on subacute diazinon-induced oxidative stress and inflammation in rats

In today's world, pesticides are commonly used to control pests and in advanced agriculture. As an organophosphorus insecticide (OPI), diazinon (DZN) is a commonly used substance. However, the widespread usage of DZN increases the probability of incidence of toxication. This toxication has been reported to be shaped not through cholinergic syndromes that are experienced as a result of acetylcholinesterase inhibition, which is the primary effect of these cases. It is rather shaped by the altering of the facilitation of oxidative stress and inflammatory response. In this study, the protective effect of administering erdosteine (ERDOS) subacute DZN exposure was investigated. A total of 24 male Wistar albino rats were separated into 4 groups (with 6 rats in each group), namely, the control, DZN (15 mg/kg/day), ERDOS (10 mg/kg/day), and DZN + ERDOS (15 mg/kg/day DZN + 10 mg/kg/day ERDOS) groups. These medications were given through oral gavage for 28 days. With the whole blood, plasma, and serum samples taken from the rats, oxidant-antioxidant parameters and cytokine levels were measured. The MDA and NOx levels and SOD and CAT enzyme activities of the DZN group were higher than those of the control group, while the GSH levels and TAC and GPx activities of the DZN group were lower than those of the control group (p < 0.05). It was also found that cytokine (IL-1β, IL-10, and TNF-α) levels in the DZN group were higher than those in the control group (p < 0.05). On the other hand, the ERDOS implementations were detected to ameliorate the harmful effects of DZN on the oxidant-antioxidant parameters and cytokine levels (p < 0.05). Conclusively, besides the known mucolytic efficacy of ERDOS, it may also be stated to display free radical scavenger, antioxidant, and anti-inflammatory characteristics to inhibit some proinflammatory cytokines that are specifically involved in oxidative stress. Additionally, the ameliorating property of ERDOS can be benefited from in possible DZN-induced toxication cases.

Multifaceted Beneficial Effects of Erdosteine: More than a Mucolytic Agent

Erdosteine is a drug approved for the treatment of acute and chronic pulmonary diseases, originally developed as a mucolytic agent. It belongs to the thiol-based family of drugs that are known to also possess potentially important antioxidant and anti-inflammatory properties, and exhibit antibacterial activity against a variety of medically important bacterial species. Erdosteine is a prodrug that is metabolized to the ring-opening compound metabolite M1 (MET 1), which has mucolytic properties. Experimental studies have documented that erdosteine prevents or reduces lung tissue damage induced by oxidative stress and, in particular, that Met 1 also regulates reactive oxygen species production. The RESTORE study, which has been the only trial that investigated the effects of a thiol-based drug in chronic obstructive pulmonary disease (COPD) frequent exacerbators, documented that erdosteine significantly reduces the risk of acute exacerbations of COPD (AECOPDs), shortens their course, and also decreases the risk of hospitalization from COPD. The preventive action of erdosteine on AECOPDs was not affected by the presence or absence of inhaled corticosteroids (ICSs) or blood eosinophil count. These findings clearly contrast with the Global Initiative for Chronic Obstructive Lung Disease strategy’s approach to use erdosteine only in those COPD patients not treated simultaneously with an ICS. Furthermore, they support the possibility of using erdosteine in a step-down approach that in COPD is characterized by the withdrawal of the ICS.

Aliskiren attenuates bleomycin-induced pulmonary fibrosis in rats: focus on oxidative stress, advanced glycation end products, and matrix metalloproteinase-9

Pulmonary fibrosis is a progressive lung disorder with high mortality rate and limited successful treatment. This study was designed to assess the potential anti-oxidant and anti-fibrotic effects of aliskiren (Alsk) during bleomycin (BLM)-induced pulmonary fibrosis. Male Wistar rats were used as control untreated or treated with the following: a single dose of 2.5 mg/kg of BLM endotracheally and BLM and Alsk (either low dose 30 mg/kg/day or high dose 60 mg/kg/day), and another group was given Alsk 60 mg/kg/day alone. Alsk was given by gavage. Alsk anti-oxidant and anti-fibrotic effects were assessed. BLM significantly increased relative lung weight and the levels of lactate dehydrogenase and total and differential leucocytic count in bronchoalveolar lavage that was significantly ameliorated by high-dose Alsk treatment. As markers of oxidative stress, BLM caused a significant increase in the levels of lipid peroxides and nitric oxide accompanied with a significant decrease of superoxide dismutase and glutathione transferase enzymes. High-dose Alsk treatment restored these markers toward normal values. Alsk counteracted the overexpression of advanced glycation end products, matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinases-1 in lung tissue induced by BLM. Fibrosis assessed by measuring hydroxyproline content, which markedly increased in the BLM group, was also significantly reduced by Alsk. These were confirmed by histopathological and immunohistochemical examination which revealed that Alsk attenuates signs of pulmonary fibrosis and decreased the overexpressed MMP-9 and transforming growth factor β1. Collectively, these findings indicate that Alsk has a potential anti-fibrotic effect beside its anti-oxidant activity.

Reciprocal regulation of TGF-β and reactive oxygen species: A perverse cycle for fibrosis

Transforming growth factor beta (TGF-β) is the most potent pro-fibrogenic cytokine and its expression is increased in almost all of fibrotic diseases. Although signaling through Smad pathway is believed to play a central role in TGF-β's fibrogenesis, emerging evidence indicates that reactive oxygen species (ROS) modulate TGF-β's signaling through different pathways including Smad pathway. TGF-β1 increases ROS production and suppresses antioxidant enzymes, leading to a redox imbalance. ROS, in turn, induce/activate TGF-β1 and mediate many of TGF-β's fibrogenic effects, forming a vicious cycle (see graphic flow chart on the right). Here, we review the current knowledge on the feed-forward mechanisms between TGF-β1 and ROS in the development of fibrosis. Therapeutics targeting TGF-β-induced and ROS-dependent cellular signaling represents a novel approach in the treatment of fibrotic disorders.

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TGF-β1 is the most potent ubiquitous profibrogenic cytokine.

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TGF- β 1 induces redox imbalance by ↑ ROS production and ↓ anti-oxidant defense system

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Redox imbalance, in turn, activates latent TGF-β1 and induces TGF-β1 expression.

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Redox imbalance also mediates many of TGF-β1’s profibrogenic effects

Passion fruit peel extract attenuates bleomycin-induced pulmonary fibrosis in mice

Idiopathic pulmonary fibrosis is a progressive fatal lung disease characterized by excessive collagen deposition, with no effective treatments. We investigated the efficacy of natural products with high anti-inflammatory activity, such as passion fruit peel extract (PFPE), in a mouse model of bleomycin-induced pulmonary fibrosis (PF). C57BL/6J mice were subjected to a single intratracheal instillation of bleomycin to induce PF. Daily PFPE treatment significantly reduced loss of body mass and mortality rate in mice compared with those treated with bleomycin. While bleomycin-induced PF resulted in elevated total numbers of inflammatory cells, macrophages, lymphocytes, and neutrophils in bronchoalveolar lavage fluid on both days 7 and 21, PFPE administration significantly attenuated these phenomena compared with bleomycin group. On day 7, the decreased superoxide dismutase and myeloperoxidase activities observed in the bleomycin group were significantly restored with PFPE treatment. On day 21, enhanced hydroxyproline deposition in the bleomycin group was also suppressed by PFPE administration. PFPE treatment significantly attenuated extensive inflammatory cell infiltration and accumulation of collagen in lung tissue sections of bleomycin-induced mice on days 7 and 21, respectively. Our results indicate that administration of PFPE decreased bleomycin-induced PF because of anti-inflammatory and antioxidant activities.

Altered mitochondrial biogenesis and its fusion gene expression is involved in the high-altitude adaptation of rat lung

Intermittent hypobaric hypoxia-induced preconditioning (IHH-PC) of rat favored the adaption of lungs to severe HH conditions, possibly through stabilization of mitochondrial function. This is based on the data generated on regulatory coordination of nuclear DNA-encoded mitochondrial biogenesis; dynamics, and mitochondrial DNA (mtDNA)-encoded oxidative phosphorylation (mtOXPHOS) genes expression. At 16th day after start of IHH-PC (equivalent to 5000m, 6h/d, 2w of treatment), rats were exposed to severe HH stimulation at 9142m for 6h. The IHH-PC significantly counteracted the HH-induced effect of increased lung: water content; tissue damage; and oxidant injury. Further, IHH-PC significantly increased the mitochondrial number, mtDNA content and mtOXPHOS complex activity in the lung tissues. This observation is due to an increased expression of genes involved in mitochondrial biogenesis (PGC-1α, ERRα, NRF1, NRF2 and TFAM), fusion (Mfn1 and Mfn2) and mtOXPHOS. Thus, the regulatory pathway formed by PGC-1α/ERRα/Mfn2 axes is required for the mitochondrial adaptation provoked by IHH-PC regimen to counteract subsequent HH stress.

Adaptability to hypobaric hypoxia is facilitated through mitochondrial bioenergetics: an in vivo study

BACKGROUND AND PURPOSE

High-altitude pulmonary oedema (HAPE) experienced under high-altitude conditions is attributed to mitochondrial redox distress. Hence, hypobaric hypoxia (HH)-induced alteration in expression of mitochondrial biogenesis and dynamics genes was determined in rat lung. Further, such alteration was correlated with expression of mitochondrial DNA (mtDNA)-encoded oxidative phosphorylation (mtOXPHOS) genes. The prophylactic effect of dexamethasone (DEX) in counteracting the HH-induced mitochondrial distress was used as control to understand adaptation to high-altitude exposure.

EXPERIMENTAL APPROACH

Rats pretreated with DEX were exposed to normobaric normoxia (NN) or HH. HH-induced injury was assessed as an increase in lung water content, tissue damage and oxidant generation. Mitochondrial number, mtDNA content and mtOXPHOS activities were measured to determine mitochondrial function. The expression of mitochondrial biogenesis, dynamics and mtOXPHOS genes was studied.

KEY RESULTS

HH-induced lung injury was associated with decreased mitochondrial number, mtDNA content and mtOXPHOS activities. HH exposure decreased the nuclear gene oestrogen-related receptor-α (ERRα), which interacts with PPAR-γ coactivator-1α (PGC-1α) in controlling mitochondrial metabolism. Consequently, mtOXPHOS transcripts are repressed under HH. Further, HH modulated mitochondrial dynamics by decreasing mitofusin 2 (Mfn2) and augmenting fission 1 (Fis1) and dynamin-related protein 1 (Drp1) expression. Nevertheless, DEX treatment under NN (i.e. adaptation to HH) did not affect mitochondrial biogenesis and dynamics, but increased mtOXPHOS transcripts. Further, mtOXPHOS activities increased together with reduced oxidant generation. Also, DEX pretreatment normalized ERRα along with mitochondrial dynamics genes and increased mtOXPHOS transcripts to elicit the mitochondrial function under HH.

CONCLUSIONS AND IMPLICATIONS

HH stress (HAPE)-mediated mitochondrial dysfunction is due to repressed ERRα and mtOXPHOS transcripts. Thus, ERRα-mediated protection of mitochondrial bioenergetics might be the likely candidate required for lung adaptation to HH.

Modulation of cytokine and nitric oxide by mesenchymal stem cell transfer in lung injury/fibrosis

Background

No effective treatment for acute lung injury and fibrosis currently exists. Aim of this study was to investigate the time-dependent effect of bone marrow-derived mesenchymal stem cells (BMDMSCs) on bleomycin (BLM)-induced acute lung injury and fibrosis and nitric oxide metabolites and inflammatory cytokine production.

Methods

BMDMSCs were transferred 4 days after BLM inhalation. Wet/dry ratio, bronchoalveolar lavage cell profiles, histologic changes and deposition of collagen were analyzed.

Results

Nitrite, nitrate and cytokines were measured weekly through day 28. At day 7, the wet/dry ratio, neutrophilic inflammation, and amount of collagen were elevated in BLM-treated rats compared to sham rats (p = 0.05-0.002). Levels nitrite, nitrate, IL-1β, IL-6, TNF-α, TGF-β and VEGF were also higher at day 7 (p < 0.05). Degree of lymphocyte and macrophage infiltration increased steadily over time. BMDMSC transfer significantly reduced the BLM-induced increase in wet/dry ratio, degree of neutrophilic infiltration, collagen deposition, and levels of the cytokines, nitrite, and nitrate to those in sham-treated rats (p < 0.05). Fluorescence in situ hybridization localized the engrafted cells to areas of lung injury.

Conclusion

Systemic transfer of BMDMSCs effectively reduced the BLM-induced lung injury and fibrosis through the down-regulation of nitric oxide metabolites, and proinflammatory and angiogenic cytokines.

Oxidative stress and glutathione in TGF-beta-mediated fibrogenesis

Transforming growth factor beta (TGF-beta) is the most potent and ubiquitous profibrogenic cytokine, and its expression is increased in almost all the fibrotic diseases and in experimental fibrosis models. TGF-beta increases reactive oxygen species production and decreases the concentration of glutathione (GSH), the most abundant intracellular free thiol and an important antioxidant, which mediates many of the fibrogenic effects of TGF-beta in various types of cells. A decreased GSH concentration is also observed in human fibrotic diseases and in experimental fibrosis models. Although the biological significance of GSH depletion in the development of fibrosis remains obscure, GSH and N-acetylcysteine, a precursor of GSH, have been used in clinics for the treatment of fibrotic diseases. This review summarizes recent findings in the field to address the potential mechanism whereby oxidative stress mediates fibrogenesis induced by TGF-beta and the potential therapeutic value of antioxidant treatment in fibrotic diseases.

Neferine, a bisbenzylisoquinline alkaloid attenuates bleomycin-induced pulmonary fibrosis

In this study, we evaluated the potential anti-fibrotic property of neferine, a bisbenzylisoquinline alkaloid extracted from the seed embryo of Nelumbo mucifera Gaertn. Intratracheal bleomycin administration resulted in pulmonary fibrosis 14 and 21 days posttreatment, as evidenced by increased hydroxyproline content in bleomycin group (255.77+/-97.17 microg/lung and 269.74+/-40.92 microg/lung) compared to sham group (170.78+/-76.46 microg/lung and 191.24+/-60.45 microg/lung), and the hydroxyproline was significantly suppressed (193.07+/-39.55 microg/lung and 201.08+/-71.74 microg/lung) by neferine administration (20mg/kg, b.i.d). The attenuated-fibrosis condition was also validated by histological observations. Biochemical measurements revealed that bleomycin caused a significant decrease in lung superoxidae dismutase (SOD) activity, which was accompanied with a significant increase in malondialdehyde (MDA) levels and myeloperoxidase (MPO) activity on the 7th and 14th days. However, neferine reversed the decrease in SOD activity as well as the increase in MDA and MPO activity. Enzyme-linked immunosorbent assay and radio-immunity assay showed that treatment with neferine alleviated bleomycin-induced increase of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 and endothelin-1 in plasma or in tissue. Additionally, neferine blocked bleomycin-induced increases of NF-kappaB in nuclear extracts and TGF-beta(1) in total protein extracts of murine RAW264.7 macrophages. In summary, neferine attenuates bleomycin-induced pulmonary fibrosis in vitro and in vivo. The beneficial effect of neferine might be associated with its activities of anti-inflammation, antioxidation, cytokine and NF-kappaB inhibition.

Antioxidants as potential therapeutics for lung fibrosis

Interstitial lung disease encompasses a large group of chronic lung disorders associated with excessive tissue remodeling, scarring, and fibrosis. The evidence of a redox imbalance in lung fibrosis is substantial, and the rationale for testing antioxidants as potential new therapeutics for lung fibrosis is appealing. Current animal models of lung fibrosis have clear involvement of ROS in their pathogenesis. New classes of antioxidant agents divided into catalytic antioxidant mimetics and antioxidant scavengers are being developed. The catalytic antioxidant class is based on endogenous antioxidant enzymes and includes the manganese-containing macrocyclics, porphyrins, salens, and the non-metal-containing nitroxides. The antioxidant scavenging class is based on endogenous antioxidant molecules and includes the vitamin E analogues, thiols, lazaroids, and polyphenolic agents. Numerous studies have shown oxidative stress to be associated with many interstitial lung diseases and that these agents are effective in attenuating fibroproliferative responses in the lung of animals and humans.

Inflammatory related changes in lung tissue mechanics after bleomycin-induced lung injury

The impact of lung remodelling in respiratory mechanics has been widely studied in bleomycin-induced lung injury. However, little is known regarding the relationship between the amount of lung inflammation and pulmonary tissue mechanics. For this purpose, rats were intratracheally instilled with bleomycin (n=29) or saline (n=8) and sacrificed at 3, 7, or 15 days. Forced oscillatory mechanics as well as indices of remodelling (elastic fibre content and hydroxyproline) and inflammation (myeloperoxidase content, total cell count, alveolar wall thickness, and lung water content) were studied in lung tissue strips. Tissue resistance increased significantly at day 15, while hysteresivity was significantly higher in bleomycin group compared to control at all time points. Elastic fibres, hydroxyproline and myeloperoxidase contents augmented after bleomycin at days 7 and 15. Tissue resistance and hysteresivity were significantly correlated with myeloperoxidase, elastic fibre and lung water content. In conclusion, inflammatory structural changes and elastogenesis are the main determinants for hysteretic changes in this 2-week bleomycin-induced lung injury model.

Erdosteine prevents colonic inflammation through its antioxidant and free radical scavenging activities

After intracolonic administration of trinitrobenzene sulphonic acid (TNBS), Sprague-Dawley rats were treated orally either with saline or erdosteine (100 mg/kg per day), a sulfhydryl-containing antioxidant, for 3 days. On the 4th day, rats were decapitated and distal colon was removed for the macroscopic and microscopic damage scoring, for the measurement of malondialdehyde (MDA), glutathione (GSH) and collagen levels, myeloperoxidase (MPO) activity, luminol and lucigenin chemiluminescence (CL) and DNA fragmentation. Lactate dehydrogenase (LDH) activity, tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, and antioxidant capacity were assayed in blood samples. Colitis caused significant increases in the colonic CL values, macroscopic and microscopic damage scores, MDA and collagen levels, MPO activity and DNA fragmentation, along with a significant decrease in tissue GSH level. Similarly, serum cytokines and LDH were elevated in the saline-treated colitis group as compared with the control group. On the other hand, erdosteine treatment reversed all these biochemical indices, and histopathologic alterations induced by TNBS, suggesting that erdosteine protects the colonic tissue via its radical scavenging and antioxidant activities.

The protective effect of erdosteine against cyclosporine A-induced cardiotoxicity in rats

Cyclosporine A (CsA) is a frequently used immunosuppressive agent in transplant medicine to prevent rejection and in the treatment of autoimmune diseases. However, CsA generates reactive oxygen species, which causes nephrotoxicity, hepatotoxicity and cardiotoxicity. The use of antioxidants reduces the adverse effects of CsA. The aim of this study is to determine the protective effects of erdosteine on CsA-induced heart injury through tissue oxidant/antioxidant parameters and light microscopic evaluation in rats. CsA cardiotoxicity was induced by administrating an oral dose of 15mg/kg CsA daily for 21 days. The rats were divided into four groups: control group (n=4), CsA administrated group (15mg/kg, n=5), CsA+erdosteine administrated group (10mg/kg day orally erdosteine, n=4) and only erdosteine administrated group (10mg/kg day orally n=5). CsA treated rats showed increase in the number of infiltrated cells and disorganization of myocardial fibers with interstitial fibrosis. The number of infiltrated cells, disorganization of myocardial fibers and interstitial fibrosis was diminished in the hearts of CsA-treated rats given erdosteine. The malondialdehyde, the protein carbonyl content and nitric oxide levels were increased in the cyclosporine A group in comparison with the control and CsA plus erdosteine groups. The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were higher in CsA plus erdosteine group than CsA group. However, the CAT, GSH-Px and SOD activities were significantly lower in CsA group than in control group and erdosteine group. These results suggest that erdosteine has protective effect against CsA-induced cardiotoxicity.

The bleomycin animal model: a useful tool to investigate treatment options for idiopathic pulmonary fibrosis?

Different animal models of pulmonary fibrosis have been developed to investigate potential therapies for idiopathic pulmonary fibrosis (IPF). The most common is the bleomycin model in rodents (mouse, rat and hamster). Over the years, numerous agents have been shown to inhibit fibrosis in this model. However, to date none of these compounds are used in the clinical management of IPF and none has shown a comparable antifibrotic effect in humans. We performed a systematic review of publications on drug efficacy studies in the bleomycin model to evaluate the value of this model regarding transferability to clinical use. Between 1980 and 2006 we identified 240 experimental studies describing beneficial antifibrotic compounds in the bleomycin model. 222 of those used a preventive regimen (drug given < or =7 days after last bleomycin application), only 13 were therapeutic trials (>7 days after last bleomycin application). In 5 studies we did not find enough details about the timing of drug application to allow inter-study comparison. It is critical to distinguish between drugs interfering with the inflammatory and early fibrogenic response from those preventing progression of fibrosis, the latter likely much more meaningful for clinical application. All potential antifibrotic compounds should be evaluated in the phase of established fibrosis rather than in the early period of bleomycin-induced inflammation for assessment of its antifibrotic properties. Further care should be taken in extrapolation of drugs successfully tested in the bleomycin model due to partial reversibility of bleomycin-induced fibrosis over time. The use of alternative and more robust animal models, which better reflect human IPF, is warranted.

Changes in blood ROS, e-NO, and some pro-inflammatory mediators in bronchial secretions following erdosteine or placebo: a controlled study in current smokers with mild COPD

Anti-oxidant interventions consist in reduction of direct oxidant damage by removing oxidant agents and/or by supplementing reducing agents with anti-oxidant effects.

AIM

Aim of the present study was to investigate the anti-oxidant effects of erdosteine, a recent drug currently used in chronic obstructive pulmonary disease (COPD) for its rheological activity. At present, no data are available on current smokers with COPD to our knowledge.

METHODS

Two groups of 10 persons matched for sex; age (65.0 yr+/-8.4 S.D. and 65.3 yr+/-6.5 S.D.); basal FEV1 (88.7% pred +/-6.8 S.D. and 85.2% pred +/-5.8 S.D.); and cigarette consumption (25.4 pack/yr+/-3.5 S.D. and 28.1 pack/yr+/-2.3 S.D.) entered a controlled, double blind, parallel groups study. They were randomized to receive erdosteine 600 mg daily or placebo for 10 days. IL-6; IL-8; TNFalpha were measured in bronchial secretions in bsln, after 4, 7, and 10 days of Erdosteine or placebo; e-NO and both ROS and 8-Isoprostane in blood were also measured at the same experimental times.

STATISTICS

ANOVA: a t-test with Bonferroni correction; p<0.05 was accepted.

RESULTS

Blood ROS and IL-8 in bronchial secretions dropped significantly following erdosteine starting from day 4 (both p<0.01), while 8-isoprostane drop was significant only after day 10 (p<0.02), and the e-NO decrease proved evident but not significant. No significant changes were observed in the placebo group.

CONCLUSIONS

Erdosteine affects substantially some pro-inflammatory cytokines specifically involved in oxidative stress in current smokers with mild COPD. Effects appeared differently time-dependent. Further long-term studies are needed to confirm these pilot data and to assess their long-term clinical relevance.

An overview of erdosteine antioxidant activity in experimental research

Erdosteine was introduced in the market as a mucolytic agent for chronic pulmonary diseases more than 10 years ago. The drug contains two blocked sulphydryl groups one of which, after hepatic metabolization and opening of the thiolactone ring, becomes available both for the mucolytic and free radical scavenging and antioxidant activity too. There are several experimental evidences which support the protective effect of erdosteine in acute injury induced by a variety of pharmacological or noxious agents, mediated by products of oxidative stress. Experimental data in animal assigned to receive the noxious agent evidence that co-treatment with erdosteine increases the tissue antioxidant enzyme activities such as superoxide dismutase, catalase and glutathione peroxidase, compared with the toxic agent alone; meanwhile erdosteine decreases the tissue level of nitric oxide, xanthine oxidase, which catalyze oxygen-free radical production. In summary, erdosteine prevents the accumulation of free oxygen radicals when their production is accelerated and increases antioxidant cellular protective mechanisms. The final result is a protective effect on tissues which reduces lipid peroxidation, neutrophil infiltration or cell apoptosis mediated by noxious agents. Recent positive clinical trials in humans seem to fulfill the impressive promises that theory and experimental research have put forward.

Erdosteine treatment attenuates oxidative stress and fibrosis in experimental biliary obstruction

Oxidative stress, in particular lipid peroxidation, induces collagen synthesis and causes fibrosis. The aim of this study was to assess the antioxidant and antifibrotic effects of erdosteine on liver fibrosis induced by biliary obstruction in rats. Liver fibrosis was induced in Wistar albino rats by bile duct ligation (BDL). Erdosteine (10 mg/kg, orally) or saline was administered for 28 days. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels were determined to assess liver functions and tissue damage, respectively. Pro-inflammatory cytokines, TNF-alpha, IL-1beta and IL-6 and antioxidant capacity (AOC) were assayed in plasma samples. Liver tissues were taken for determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content. Production of reactive oxidants was monitored by chemiluminescence assay. Serum AST, ALT, LDH, and plasma cytokines were elevated in the BDL group as compared to controls and were significantly decreased by erdosteine treatment. Hepatic GSH level and plasma AOC, depressed by BDL, were elevated back to control level with erdosteine treatment. Furthermore, hepatic luminol and lucigenin chemiluminescence (CL), MDA level, MPO activity and collagen content in BDL group increased dramatically compared to control and reduced by erdosteine treatment. Since erdosteine administration alleviated the BDL-induced oxidative injury of the liver and improved the hepatic functions, it seems likely that erdosteine with its antioxidant and antifibrotic properties, may be of potential therapeutic value in protecting the liver fibrosis and oxidative injury due to biliary obstruction.

Resveratrol alleviates bleomycin-induced lung injury in rats

Antioxidant therapy may be useful in diseases with impaired oxidant-antioxidant balance such as pulmonary fibrosis. This study was designed to examine the effects of resveratrol, an antioxidant agents, against bleomycin-induced pulmonary fibrosis and oxidative damage. Wistar albino rats were administered a single dose of bleomycin (5 mg/kg; via the tracheal cannula) followed by either saline or resveratrol (10 mg/kg; orally) for 14 days. The effect of resveratrol on pulmonary oxidative damage was studied by cell count and analysis of cytokine levels (TGF-beta, TNF-alpha, IL-1beta and IL-6) in the bronchoalveolar lavage fluid (BALF) and biochemical measurements of malondialdehyde (MDA), an end product of lipid peroxidation; glutathione (GSH), a key antioxidant; and myeloperoxidase (MPO) activity, an index of neutrophil infiltration, in the lung tissue. Bleomycin-induced lung fibrosis was determined by lung collagen contents and also microscopically. Bleomycin caused a significant decrease in lung GSH, which was accompanied with significant increases in MDA level, MPO activity, and collagen contents of the lung tissue concomitant with increased levels of the pro-inflammatory mediators and cell count in BALF. On the other hand, resveratrol treatment reversed all these biochemical indices as well as histopathological alterations induced by bleomycin. The results demonstrate the role of oxidative mechanisms in bleomycin-induced pulmonary fibrosis, and resveratrol, by its antioxidant properties, ameliorates oxidative injury and fibrosis due to bleomycin. Thus, an effective supplement with resveratrol as an adjuvant therapy may be a very promising agent in alleviating the side effects of bleomycin, an effective chemotherapeutic agent.