Effects of erdosteine on smoking-induced lipid peroxidation in healthy smokers

The influence of erdosteine administration on lead-induced oxidative stress in rat muscle

Lead-exposure is known to disrupt the redox balance of tissues leading to oxidative stress. Due to the fact that a mucolytic drug, erdosteine, exerts also antioxidant properties, we decided to perform a pilot study on rats to evaluate its therapeutic potency in lead poisoning. Male Wistar rats were divided randomly into the following seven groups having 10 animals in each. Group I served as the control group. During 8-week period, rats in groups II-IV, except standard alimentation, received: erdosteine in a dose 350 mg/kg (collateral control group), 1200 ppm of lead acetate in drinking water and placebo, as well as the same doses of lead and erdosteine, respectively. Rats in group V-VII received 1200 ppm of lead acetate in drinking water for the initial 6-week period and then administered: placebo, erdosteine and EDTA for 2 weeks, respectively. The levels of malondialdehyde (MDA) were significantly higher in groups III and V compared to the control group. The activities of catalase (CAT) were significantly higher in groups IV, V, and VI compared to the control group. The activities of glutathione-S-transferase (GST) were significantly lower in group II and significantly higher in groups VI and VII compared to the control group, while the activities of glutathione reductase (GR) were significantly lower in group III and significantly higher in group VI. Erdosteine has an effect of protection against lead-induced oxidative stress which is not worse than that of EDTA.

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.

Associations between Lifestyle Factors and Vitamin E Metabolites in the General Population

The antioxidant vitamin E (α-tocopherol, α-TOH) protects lipids from oxidation by reactive oxygen species. We hypothesized that lifestyle factors associate with vitamin E metabolism marked by urinary α-tocopheronolactone hydroquinone (α-TLHQ) and α-carboxymethyl-hydroxychroman (α-CEHC levels), as potential reflection of lipid oxidation. We conducted a cross-sectional study in the Netherlands Epidemiology of Obesity Study. Serum α-TOH, and urinary α-TLHQ and α-CEHC were quantified by liquid chromatography coupled with tandem mass spectrometry. Information on the lifestyle factors (sleep, physical activity (PA), smoking and alcohol) were collected through questionnaires. Multivariable linear regression analyses were performed to assess the associations between the lifestyle factors and α-TOH measures. A total of 530 participants (46% men) were included with mean (SD) age of 56 (6) years. Of the examined lifestyle factors, only poor sleep was associated with a higher serum α-TOH (mean difference: 4% (95% CI: 1, 7%)). Current smoking was associated with higher urinary α-CEHC (32%: (14%, 53%)), with evidence of a dose–response relationship with smoking intensity (low pack years, 24% (2, 52%); high pack years, 55% (25, 93%)). Moderate physical activity was associated with a lower α-TLHQ relative to α-CEHC (−17%: (−26, −6%), compared with low PA). Only specific lifestyle factors associate with vitamin E metabolism. Examining serum α-TOH does not provide complete insight in vitamin E antioxidant capacity.

Pharmacology and clinical efficacy of erdosteine in chronic obstructive pulmonary disease

Erdosteine is a multimechanism, mucolytic agent that decreases the sputum viscoelastic properties and bacterial adhesion to the cell membrane, endowed with bronchial anti-inflammatory activity and a scavenging effect on free oxidant radicals. Erdosteine is a prodrug and metabolite I is the active metabolite of erdosteine owing to its free thiol group. In acute infective exacerbation of chronic bronchitis or chronic obstructive pulmonary disease (COPD), adding erdosteine to standard treatment significantly modified the outcome by improving the symptoms and reducing the length of disease. Furthermore, erdosteine has shown a synergism with antibiotic therapy. In stable COPD patients, long-term treatment with erdosteine had a protective effect against exacerbations by reducing the rate of exacerbations and hospitalizations in the study period. A total of 8 months of treatment with erdosteine significantly improved the patients' health status and preserved lung function. Erdosteine has a scavenging effect on free oxidant radicals by a direct and indirect antioxidative effect and the final result is a protective effect against tissue damage, as demonstrated in animal studies. In view of the persuasive evidence that oxidative stress is important in the pathophysiology of COPD, erdosteine appears to be a logical approach to therapy.

Beneficial effect of erdosteine on methotrexate-induced testicular toxicity in mice

Methotrexate is used to treat certain types of cancer of the breast, skin, head and neck, or lung. Methotrexate can cause serious or life-threatening side effects on liver, lungs, kidneys, and immune system. Methotrexate chemotherapy causes testicular damage in humans. The aim of this study was to investigate the possible protective role of erdosteine on testicular toxicity of methotrexate in mice. Twenty-six male mice were divided into four groups as follows: group 1, control; group 2, erdosteine-treated; group 3, methotrexate-treated; and group 4, methotrexate + erdosteine treated. On the first day of experiment, a single dose of methotrexate was intraperitoneally administered to groups 3 and 4, although a daily single dose of erdosteine was orally administered to group 2 and 4 for 7 days. At the end of the experiment, the testes of the animals were removed and weighed. The levels of total antioxidant capacity and total oxidative stress, and myeloperoxidase activity in the methotrexate group were higher than the control group (p<0.05). Lipid peroxidation levels were not changed in methotrexate group compared with control group. In conclusion, erdosteine could effectively protect the testes in methotrexate-induced toxicity.

Erdosteine: its relevance in COPD treatment

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a progressive condition characterized by airflow limitation, which is largely irreversible; the oxidant/antioxidant imbalance is important in the pathogenesis of this condition.

OBJECTIVE

To show that administration of erdosteine, a mucolytic agent with a prevalent antioxidant activity, could play a beneficial role in COPD.

METHODS

To review the experimental and clinical trials on erdosteine in COPD and chronic bronchitis.

RESULTS

Erdosteine is a thiol agent with a multifactorial mechanism of action, namely: mucolytic, antibacterial, antioxidant and anti-inflammatory activity. In the acute exacerbation of chronic bronchitis/COPD, addition of erdosteine 300 mg twice a day for 7 - 10 days to standard treatment improves the symptoms and reduces the time of disease. In clinically stable COPD, long-term treatment is associated with a reduction in acute exacerbation and hospitalization rate and a significant improvement of quality of life. Erdosteine could be most beneficial in patients who have repeated, prolonged or severe exacerbations of COPD.

Erdosteine enhances airway response to salbutamol in patients with mild-to-moderate COPD

Background: Oxidative stress is presumed to impair β-adenoceptor function and airway patency. Erdosteine (E), a mucomodulatory compound, has shown important antioxidant properties.

Methods: The objective was to assess the effect of antioxidant interventions on short-term airway response to salbutamol in non-reversible mild-to-moderate COPD patients. Thirty COPD patients (GOLD class 1—2), current smoker (≥10 pack/year), randomly received E 300 mg, N-acetylcysteine (NAC) 600 mg, or placebo, twice daily for ten days. Reversibility to salbutamol 200 μg was tested in baseline, after four and ten days of each treatment. ROS and 8-isoprostane blood levels were measured on the same days. Between-treatment comparison was performed by ANOVA and t-test or Wilcoxon test, and p<0.05 assumed. E enhanced FEV1 reversibility after four and ten days significantly (+5.1% and +5.0%; both p<0.01 vs. placebo), while NAC only showed a transient effect at day 4 (+3.0%, p<0.05), but not at day 10 (+1.3%, p = ns).

Results: E and NAC caused significant drops in ROS blood levels after four and ten days (p<0.001 and p<0.0001 vs. placebo). In contrast to NAC, E lowered 8-isoprostane levels substantially for ten days (p = 0.017 and p = 0.0004 vs. placebo, respectively). Only E restored significantly short-term reversibility in COPD patients previously unresponsive to β2-adrenergics.

Conclusions: This effect seems more related to the peculiar protection against lipid peroxidation rather than to the scavenging activity, which proves equal to that of NAC. E provides a sort of indirect bronchodilation through 're-sensitisation' of β 2-adrenoceptors. Once confirmed in further controlled studies, it may be useful in long-term treatment of COPD.

Evaluation of nitrate influence on thyroid volume of adults in a previously iodine-deficient area

OBJECTIVE

The aim of the present study was to analyze the influence of nitrate as a possible alimentary goitrogen on thyroid volume in a previously iodine-deficient area.

DESIGN

Population based cross-sectional epidemiologic survey.

PARTICIPANTS

Data of 3772 participants (20-79 years) of the Study of Health in Pomerania without diagnosed thyroid disorders were analyzed. EVALUATION AND MEASUREMENTS: The nitrate concentration in spot urine was determined by ion chromatography. High nitrate levels were defined as urine nitrate concentrations exceeding the 75th percentile for the investigated population. Thyroid structure and size were measured by ultrasound. Subjects were divided into two groups with absence or presence of high urine nitrate concentrations. Comparisons between groups were made using the chi(2)-test or the Student's t-test. Multivariable analyses were done by logistic regression and ANOVA (analysis of variance). Odds ratios and their 95% confidence intervals as well as adjusted means (standard error) were calculated.

RESULTS

In the whole population, the mean urine nitrate level was 53.1+/-0.8mg/l. The 75th percentile of urine nitrate concentrations was 69.0mg/l, indicating that the renal excretion of nitrate is at a low level. The proportion of goiter in subjects with and without high urine nitrate concentrations was 35.5% and 34.7%, respectively (p=0.69). Analyses considering age, sex and further potential confounders could not identify an association between the exposure variable and the risk of goiter.

CONCLUSION

The low level of the alimentary nitrate intake does not influence the thyroid volume in a population with currently sufficient alimentary intake of iodine.

Erdosteine: antitussive and anti-inflammatory effects

Erdosteine is a multifactorial drug currently used in COPD for its rheologic activity on bronchial secretions and its positive effects on bacterial adhesiveness. Erdosteine produces an active metabolite (Met 1) which was shown to produce antioxidant effects during the respiratory burst of human PMNs, due to the presence of an SH group. The substantial antitussive effects of erdosteine were first documented in clinical trials even though mucolytic agents are regarded as not consistently effective in ameliorating cough in patients with bronchitis, although they may be of benefit to this population in other ways. Actually, a mucolytic drug could exert antitussive effects if it also affects mucus consistency and enhances ciliary function. In the last decade, data from several studies on animal models pointed to the possible antitussive and anti-inflammatory properties of erdosteine and an indirect anti-inflammatory mechanism of action was suggested. Recently, data from some controlled versus placebo studies documented the antioxidant properties of erdosteine in humans and in current smokers with COPD. The mechanism of action was described as related to erdosteine's ability to inhibit some inflammatory mediators and some pro-inflammatory cytokines that are specifically involved in oxidative stress. As oxidative stress is also presumed to impair beta-adrenoceptor function and contribute to airway obstruction, specific controlled studies recently investigated the effect of antioxidant intervention on short-term airway response to salbutamol in nonreversible COPD, according to a double-blind design versus placebo and NAC. Only erdosteine consistently restored a significant short-term reversibility in COPD subjects, previously unresponsive to beta(2) adrenergics. This peculiar activity of erdosteine (to our knowledge never previously assessed) proved related to the ROS scavenging activity (which actually proved equal to that of N), and its significant inhibiting effect on lipoperoxidation (8-isoprostane) proved discriminant between treatments, with antioxidant and anti-inflammatory effects the main determinants of the erdosteine multifactorial properties. In addition, antitussive effects may be regarded as related to its anti-inflammatory properties via the improvement of mucociliary clearance and the reduction of chemokines from epithelial cells. Finally, a sort of "sensitization" of 2-adrenoceptors can also be speculated due to the same mechanisms of action; if confirmed by further controlled studies, this particular property would suggest a novel therapeutic role of erdosteine in COPD.

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.