Cough in chronic obstructive pulmonary disease

Casticin Improves Respiratory Dysfunction and Attenuates Oxidative Stress and Inflammation via Inhibition of NF-ĸB in a Chronic Obstructive Pulmonary Disease Model of Chronic Cigarette Smoke-Exposed Rats

Objective

The present study was conducted to elucidate the protective effect of Casticin against chronic obstructive pulmonary disease (COPD) in rats.

Methods

The COPD in rats was induced by the controlled cigarette smoke, and CST (10, 20, and 30 mg/kg) was injected into the cigarette-smoke exposed rats. Blood was taken from the abdominal vein and centrifuged (1500×g, 4°C, 15min); plasma was collected and used for the determination of various biochemical parameters.

Results

The results of the study suggested that CST significantly improved the lung functions of the rats in a dose-dependent manner. It also causes a reduction of white blood cells, neutrophils, and macrophages in BALF of rats. The plasma level of leptin and C-reactive protein together with pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) were also significantly restored to near to normal in CST-treated group. In Western blot analysis, CST causes significant inhibition of the NF-ĸB and iNOS pathway.

Conclusion

Our study demonstrated that the CST protects lungs against COPD via improving lung functions and inhibition of oxidative stress and inflammation.

Acid-sensing by airway afferent nerves

Inhalation of acid aerosol or aspiration of acid solution evokes a stimulatory effect on airway C-fiber and Aδ afferents, which in turn causes airway irritation and triggers an array of defense reflex responses (e.g., cough, reflex bronchoconstriction, etc.). Tissue acidosis can also occur locally in the respiratory tract as a result of ischemia or inflammation, such as in the airways of asthmatic patients during exacerbation. The action of proton on the airway sensory neurons is generated by activation of two different current species: a transient (rapidly activating and inactivating) current mediated through the acid-sensing ion channels, and a slowly activating and sustained current mediated through the transient receptor potential vanilloid type 1 (TRPV1) receptor. In view of the recent findings that the expression and/or sensitivity of TRPV1 are up-regulated in the airway sensory nerves during chronic inflammatory reaction, the proton-evoked irritant effects on these nerves may play an important part in the manifestation of various symptoms associated with airway inflammatory diseases.

The validity and precision of the Leicester Cough Questionnaire in COPD patients with chronic cough

Background

A validated instrument to assess the effects of chronic cough on health status in patients with chronic obstructive pulmonary disease (COPD) is currently not available. The Leicester Cough Questionnaire (LCQ) is a cough-specific health status questionnaire which is originally validated for a population of general patients presenting with chronic cough. We examined the psychometric performance of the LCQ in patients with COPD and chronic productive cough.

Methods

Concurrent validity, internal consistency, reproducibility and responsiveness were determined. The St. George's Respiratory Questionnaire (SGRQ) and the Short Form-36 (SF-36) were used as external criteria. Questionnaires were completed at the start of the study. After 2 and 12 weeks the LCQ was repeated, together with a global rating of change.

Results

In total 54 patients were included. Concurrent validity analysis showed significant correlations between corresponding domains of the LCQ and the SGRQ (r_s -0.31 to -0.60). Corresponding domains of the LCQ and the SF-36 showed weaker correlations (r_s 0.04 to 0.41). Internal consistency was adequate for two of the three domains (Cronbach's α 0.74 - 0.86). Test-retest reliability in stable patients was high (intraclass correlation coefficients 0.79 - 0.93). The mean difference after two weeks was 0.73 (± 1.75). Responsiveness analysis indicated that the LCQ was able to detect changes after 12 weeks.

Conclusion

The LCQ is a valid, reliable, responsive instrument to measure health status in COPD patients with chronic productive cough.

Trial Registration

ClinicalTrials.gov: NCT01071161

A pilot study of the multiherb Kampo medicine bakumondoto for cough in patients with chronic obstructive pulmonary disease

OBJECTIVES

To evaluate the effect of bakumondoto, Kampo medicine, on cough in patients with chronic obstructive pulmonary disease (COPD).

DESIGN

A 16-week, randomized, open-labeled, cross-over design.

SETTING

Outpatient clinics at one university hospital and two general hospitals in Japan from May 2007 to March 2009.

PARTICIPANTS

Twenty-four elderly patients (14 men and 9 women aged over 65) with COPD.

INTERVENTION

Treatment with or without bakumondoto for 8 weeks in a cross-over design.

MEASUREMENTS

The primary outcome measurements were the frequency and intensity of cough assessed by a visual analogue scale (VAS) and a daily cough diary. Secondary outcome measurements were quality of life (QOL) assessed using St. George's Respiratory Questionnaire (SGRQ) and lung functions measured using spirometry.

RESULTS

Treatment with bakumondoto significantly improved cough severity during the first treatment period (week 0 vs. week 8, p=0.004) and showed a trend to decrease during the second treatment period (week 8 vs. week 16, p=0.129) assessed by the VAS. Neither QOL nor lung function was affected by the treatment with bakumondoto.

CONCLUSION

Bakumondoto may be effective in suppressing cough in elderly patients with COPD. To further confirm the efficacy, a larger and placebo-controlled study with objective cough assessment is necessary.

Modulation of sensory nerve function and the cough reflex: understanding disease pathogenesis

To cough is a protective defence mechanism that is vital to remove foreign material and secretions from the airways and which in the normal state serves its function appropriately. Modulation of the cough reflex pathway in disease can lead to inappropriate chronic coughing and an augmented cough response. Chronic cough is a symptom that can present in conjunction with a number of diseases including chronic obstructive pulmonary disease (COPD) and asthma, although often the cause of chronic cough may be unknown. As current treatments for cough have proved to exhibit little efficacy and are largely ineffective, there is a need to develop novel, efficacious and safe antitussive therapies. The underlying mechanisms of the cough reflex are complex and involve a network of events, which are not fully understood. It is accepted that the cough reflex is initiated following activation of airway sensory nerves. Therefore, in the hope of identifying novel antitussives, much research has focused on understanding the neural mechanisms of cough provocation. Experimentally this has been undertaken using chemical or mechanical tussive stimuli in conjunction with animal models of cough and clinical cough assessments. This review will discuss the neural mechanisms involved in the cough, changes that occur under pathophysiological conditions and and how current research may lead to novel therapeutic opportunities for the treatment of cough.

Analysis and evaluation of environmental tobacco smoke exposure as a risk factor for chronic cough

Exposure to environmental tobacco smoke (ETS) and active tobacco smoking has been shown to increase symptoms of bronchial asthma such as bronchoconstriction but effects on other respiratory symptoms remain poorly assessed. Current levels of exposure to tobacco smoke may also be responsible for the development of chronic cough in both children and adults. The present study analyses the effects of tobacco smoke exposure as potential causes of chronic cough. A panel of PubMed-based searches was performed relating the symptom of cough to various forms of tobacco smoke exposure. It was found that especially prenatal and postnatal exposures to ETS have an important influence on children's respiratory health including the symptom of cough. These effects may be prevented if children and pregnant women are protected from exposure to ETS. Whereas the total number of studies adressing the relationship between cough and ETS exposure is relatively small, the present study demonstrated that there is a critical amout of data pointing to a causative role of environmental ETS exposure for the respiratory symptom of cough. Since research efforts have only targeted this effect to a minor extent, future epidemiological and experimental studies are needed to further unravel the relation between ETS and cough.

Analysing the causes of chronic cough: relation to diesel exhaust, ozone, nitrogen oxides, sulphur oxides and other environmental factors

Air pollution remains a leading cause of many respiratory diseases including chronic cough. Although episodes of incidental, dramatic air pollution are relatively rare, current levels of exposure of pollutants in industrialized and developing countries such as total articles, diesel exhaust particles and common cigarette smoke may be responsible for the development of chronic cough both in children and adults. The present study analyses the effects of common environmental factors as potential causes of chronic cough. Different PubMed-based researches were performed that related the term cough to various environmental factors. There is some evidence that chronic inhalation of diesel can lead to the development of cough. For long-term exposure to nitrogen dioxide (NO2), children were found to exhibit increased incidences of chronic cough and decreased lung function parameters. Although a number of studies did not show that outdoor pollution directly causes the development of asthma, they have demonstrated that high levels pollutants and their interaction with sunlight produce ozone (O3) and that repeated exposure to it can lead to chronic cough. In summary, next to the well-known air pollutants which also include particulate matter and sulphur dioxide, a number of other indoor and outdoor pollutants have been demonstrated to cause chronic cough and therefore, environmental factors have to be taken into account as potential initiators of both adult and pediatric chronic cough.

The physiology of cough

Cough is comprised of three phases (inspiratory, compressive and expiratory) and serves as a vital defensive mechanism for lung health. It prevents pulmonary aspiration, promotes ciliary activity and clears airway debris. The importance of an intact cough mechanism is reflected in the occurrence of pulmonary problems when cough is inefficient. Cough efficiency is dependent on physical/mechanical aspects (respiratory muscles, mucus, airway calibre and larynx) and integrity of the neurophysiological pathway of cough. The understanding of the latter has progressed significantly (albeit mostly in animals) with the discovery of vanniloid receptors (and subtypes) and, more recently, by the characterisation of distinct cough receptors. However, the relative contributions of previously described airway afferents/receptors to cough are still disputed. Plasticity of the peripheral and central afferent pathways in cough has recently been shown to be important in pathological states associated with increased cough. To date, little is known of the developmental aspects of cough.