Airway Defense Control Mediated via Voltage-Gated Sodium Channels

Expression of voltage-gated sodium channels (Nav) takes place in the airways and the role of Nav1.7 and Nav1.8 in the control of airway's defense reflexes has been confirmed. The activation of Nav channels is crucial for cough initiation and airway smooth muscle reactivity, but it is unknown whether these channels regulate ciliary beating. This study evaluated the involvement of Nav1.7 and Nav1.8 channels in the airway defense mechanisms using their pharmacological blockers in healthy guinea pigs and in the experimental allergic asthma model. Asthma was modeled by ovalbumin sensitization over a period of 21 days. Blockade of Nav1.7 channels significantly decreased airway smooth muscle reactivity in vivo, the number of cough efforts, and the cilia beat frequency in healthy animals. In the allergic asthma model, blockade of Nav1.8 efficiently relieved symptoms of asthma, without adversely affecting cilia beat frequency. The study demonstrates that Nav1.8 channel antagonism has a potential to alleviate cough and bronchial hyperreactivity in asthma.

The Role of Ion Channels to Regulate Airway Ciliary Beat Frequency During Allergic Inflammation

Overproduction of mucus is a hallmark of asthma. The aim of this study was to identify potentially effective therapies for removing excess mucus. The role of voltage-gated (Kir 6.1, KCa 1.1) and store-operated ion channels (SOC, CRAC) in respiratory cilia, relating to the tracheal ciliary beat frequency (CBF), was compared under the physiological and allergic airway conditions. Ex vivo experiments were designed to test the local effects of Kir 6.1, KCa 1.1 and CRAC ion channel modulators in a concentration-dependent manner on the CBF. Cilia, obtained with the brushing method, were monitored by a high-speed video camera and analyzed with ciliary analysis software. In natural conditions, a Kir 6.1 opener accelerated CBF, while CRAC blocker slowed it in a concentration-dependent manner. In allergic inflammation, the effect of Kir 6.1 opener was insignificant, with a tendency to decrease CBF. A cilio-inhibitory effect of a CRAC blocker, while gently reduced by allergic inflammation, remained significant. A KCa 1.1 opener turned out to significantly enhance the CBF under the allergic OVA-sensitized conditions. We conclude that optimally attuned concentration of KCa 1.1 openers or special types of bimodal SOC channel blockers, potentially given by inhalation, might benefit asthma.

The role of cytokines in degenerative spine disorders

Background: Degenerative spine disorders (DSD) are the most frequent reason of morbidity in adults. Commonly DSD includes degenerative disorders of intervertebral discs (IVDs), spinal stenosis and degenerative spondylolisthesis (SL). There is increasing evidence about significant role of cytokines in DSD pathogenesis, symptomathology and progression, but their protective levels remain still unknown.

Material and Methods: The aim of presented study was to provide quantitative and qualitative analysis of cytokine, chemokine and growth factors levels in individual parts of IVDs - annulus fibrosus (AF) and nucleus pulposus (NP) - separately and in facet joints (FJ) subchondral bone of patients with DSD and in controls - healthy subjects during a multiorgan procurement procedure. Bio-Plex® assay was used to measure concentrations of 27 different cytokines in tissue of patients with DSD. Their concentrations in tissues of healthy subjects during a multiorgan procurement procedure represented protective levels.

Results: The Bio-Plex® assay revealed significant differences between the patients suffered from degenerated and herniated IVDs and from lumbar SL and controls in cytokines, chemokines and growth factor profiles suggested that pro-inflammatory changes of both NP and AF were dominated in herniated IVDs, whereas the same tissue of lumbar SL patients exhibited much more complex changes in cytokine levels suggested o only ongoing inflammation (IL-6, IL-8, MCP-1, TNF-α), abut also antiinflammatory processes (IL-ra, IL-10) or connective tissue remodeling (PDGF-bb, IL-17, VEGF). The different mediators were found elevated in lumbar SL samples of subchondral FJ bone. These also confirmed ongoing inflammation, accelerated bone resorption and formation and increased fibroblasts activity in FJ bone.

Conclusion: The study supported the significant involvement of several cytokines, chemokines and growth factors in the pathogenesis of DSD. These cytokines should represent future potential targets for new biological treatment able to slow DSD progression as well as factor determining prognosis of DSD.

Experimental model of allergic asthma

The aim of the study was to prepare and evaluate the experimental model of allergic asthma. Changes in chough reflex, bronchoconstriction and the degree of inflammation were studied in ovalbumin (OVA) sensitized guinea pigs after 0, 7, 14, 21 days of exposure. The cough reflex was induced by citric acid inhalation in conscious animals in a double chamber body plethysmograph. Tracheal smooth muscle reactivity was assessed by examining the in vitro response to histamine (H) (10(-8)-10(-3) mol/l) and in vivo to H nebulization (10(-6) mol/l). BALF levels of IL-4, IL-5 and the eosinophil count were used as parameters of airway inflammation. After 7 days of OVA sensitization, there was an increase in tracheal smooth muscle contractility in vitro to cumulative concentration of H and an increase in cough parameters. After 14 days of OVA sensitization, there was a further increase in tracheal smooth muscle contractility to H, an increase in airway resistance, and a small increase in cough parameters. After 21 day of OVA sensitization, cough parameters were significantly reduced, airway resistance after H inhalation was increased, and there were significant increases in IL-4, IL-5, and eosinophils in BALF. In conclusion, progress in asthmatic inflammation during 21-day OVA sensitization caused a gradual increase in inflammatory mediators, a decline in cough reflex, and enhanced bronchoconstriction. This experimental model of allergic asthma can be used for pharmacological modulations of defense reflexes and inflammation.

CRAC ion channels and airway defense reflexes in experimental allergic inflammation

Calcium release-activated calcium channels (CRAC) play unambiguous role in secretory functions of mast cells, T cells, and eosinophils. Less knowledge exists about the role of CRAC, widely distributed in airway smooth muscle (ASM) cells, in airway contractility. The presented study seeks to determine the possible participation of CRAC in ASM-based inflammatory airway disorders in guinea pigs. The acute and long-term administration (14 days) of the CRAC antagonist 3-fluoropyridine-4-carboxylic acid was used to examine the ASM contractility and associated reflexes in the guinea pig model of allergic airway inflammation by the following methods: (i) evaluation of specific airway resistance in vivo; (ii) evaluation of the contractile response of isolated ASM strips in vitro; and (iii) citric acid-induced cough reflex; (iv) measurement of exhaled NO levels (E(NO)). Allergic airway inflammation was induced by repetitive exposure of guinea pigs to ovalbumin (10(-6) M). The CRAC antagonist administered in a single dose to guinea pigs with confirmed allergic inflammation significantly reduced the cough response and the airway resistance, which corresponded with the findings in vitro. Long-term application of the CRAC antagonist had more strongly expressed effects. The results confirm the role of CRAC in the pathophysiology of experimental animal asthma and have a potential meaning for anti-asthma therapy.

Antitussive activity of Althaea officinalis L. polysaccharide rhamnogalacturonan and its changes in guinea pigs with ovalbumine-induced airways inflammation

AIM

The presented studies were aimed on experimental confirmation of Althaea officinalis polysaccharide rhamnogalacturonan antitussive effect and its changes in conditions of allergic inflammation.

METHODS

We have tested whether rhamnogalacturonan inhibits cough reflex and modulates airways reactivity of guinea pigs in vivo. The cough in guinea pigs was induced by 0.3 M citric acid (CA) aerosol for 3 min interval, in which total number of cough efforts (sudden enhancement of expiratory flow accompanied by cough movement and sound) was counted. Specific airway resistance and its changes induced by citric acid aerosol were considered as an indicator of the in vivo reactivity changes.

RESULTS

1) Althaea officinalis polysaccharide rhamnogalacturonan dose- dependently inhibits cough reflex in unsensitized guinea pigs. Simultaneously, plant polysaccharide shortened the duration of antitussive effect when it was been tested in inflammatory conditions. 2) Rhamnogalacturonan did not influence airways reactivity in vivo conditions expressed as specific resistance values neither sensitized nor unsensitized groups of animals. 3) The antitussive activity of codeine (dose 10 mg.kg(-1) b.w. orally) tested under the same condition was comparable to higher dose of rhamnogalacturonan in unsensitized animals. 4) The characteristic cellular pattern of allergic airways inflammation was confirmed by histopathological investigations.

CONCLUSION

Rhamnogalacturonan isolated from Althaea officinalis mucilage possesses very high cough suppressive effect in guinea pigs test system, which is shortened in conditions of experimentally induced airways allergic inflammation (Tab. 1, Fig. 4, Ref. 25). Full Text in free PDF www.bmj.sk.

WITHDRAWN: The efficiency of polyphenolic compounds on allergen induced hyperreactivity of the airways

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.bionut.2010.09.002. The duplicate article has therefore been withdrawn.

Effects of flavin7 on allergen induced hyperreactivity of airways

Some studies have suggested that the polyphenolic compounds might reduce the occurrence of asthma symptoms. The aim of our experiments was to evaluate the effects of 21 days of the flavonoid Flavin7 administration on experimentally induced airway inflammation in ovalbumin-sensitized guinea pigs. We assessed tracheal smooth muscle reactivity by an in vitro muscle-strip method; changes in airway resistance by an in vivo plethysmographic method; histological picture of tracheal tissue; and the levels of interleukin 4 (IL-4), and interleukin 5 (IL-5) in bronchoalveolar lavage fluid (BALF). Histological investigation of tracheal tissue and the concentrations of the inflammatory cytokines IL-4 and IL-5 in BALF were used as indices of airway inflammation. Administration of Flavin7 caused a significant decrease of specific airway resistance after histamine nebulization and a decline in tracheal smooth muscle contraction amplitude in response to bronchoconstricting mediators. Flavin7 minimized the degree of inflammation estimated on the basis of eosinophil calculation and IL-4 and IL-5 concentrations. In conclusion, administration of Flavin7 showed bronchodilating and anti-inflammatory effects on allergen-induced airway inflammation.

The influence of animal species on the relationship between ATP-sensitive potassium ion channels and defense reflexes of the airways

BACKGROUND

The ATP-sensitive potassium ion channels (K+ATP) are widely expressed on airway sensory nerves that mediate cough and other protective reflexes; dependent on airways smooth muscles (ASM) reactivity.

OBJECTIVE

The study was conducted to determine the involvement of K+ATP in airway sensory nerves activity of different animal species.

METHODS

In this study we have evaluated the cough reflex inhibiting potential and modulation of ASM reactivity in vitro, by K+ATP opener-pinacidil in guinea pig and cats. The cough in guinea pig was induced by administration, in cats by mechanical stimulation of the airways. ASM reactivity was tested by organ tissue both method of 0.3 M citric acid aerosol at 3 min interval.

RESULTS

1) Pinacidil inhibits cough reflex in guinea pigs which was antagonized when pre-treated with K+ATP blocker glibenclamide. 2) Pinacidil exhibited antitussive activity in cats comparable to codeine and was noticeably higher than dropropizine effects. 3) ASM reactivity was significantly abolished by pinacidil and almost completely antagonized by glibenclamide in guinea pigs. 4) Pinacidil significantly attenuated ASM contraction in cats only in highest concentrations of contractile mediators.

CONCLUSION

K+ATP may be involved in mechanisms of cough reflex, likewise in antitussive activity of several more agents and also on defence reflexes dependent on ASM reactivity in different animal species such as guinea pigs and cats (Fig. 8, Ref. 20). Full Text (Free, PDF) www.bmj.sk.

A beneficial influence of provinol on the reduction of allergen induced hyperreactivity in guinea pigs

BACKGROUND

The anti-inflammatory, anti-allergic, antioxidant properties of flavonoids are known in the respiratory tract. We are interested in the role of Provinol during an allergic inflammation of the airway.

OBJECTIVES

The aim of this study was to examine the influence of an acute administration of Provinol on tracheal smooth muscle reactivity in guinea pigs and to assess the involvement of nitric oxide in the mechanism of Provinol action.

METHODS

This experiment was performed 14 days after the sensitization of animals by ovalbumin. In vivo, the specific airway conductance, as a tracheal smooth muscle reactivity parameter in response to bronchoconstrictor histamine, was evaluated after peroral administration of Provinol alone or together with L-NAME (N(omega)-nitro-L-arginine methyl ester). In vitro, Provinol alone or in combination with L-NAME were added into an organ baths before the supplement of direct bronchoconstrictor histamine, acetylcholine and the allergen ovalbumin in rising concentrations. The amplitude of the tracheal smooth muscle contraction, as a tracheal smooth muscle reactivity parameter in response to histamine, acetylcholine and ovalbumin was evaluated.

RESULTS

Our results showed that a Provinol has significant bronchodilatory activities both in vivo and in vitro.

CONCLUSION

Provinol alleviated the contraction of tracheal smooth muscle in guinea pigs sumin. Nitric oxide plays an important role in the mechanism of Provinol action (Fig. 2, Ref. 28n.(Fig. 2, Ref. 28).

Therapeutic approach to a child with acute respiratory distress syndrome: a report of two cases

The course of a respiratory disorder in a child may end up in respiratory failure. There are also acute non-respiratory diseases which have a great influence on the respiratory functions and often lead to the acute lung injury and sometimes to the acute respiratory distress syndrome (ARDS). A feature of respiratory function deterioration is changed in the surfactant system. We often see inhibition of its synthesis or damage to its structure. Therapy of children suffering from ARDS should be complex and rapid. Despite many recently published studies explaining the principle of this disorder, the mortality of ARDS is still very high (30-50%). There are several studies documenting successful administration of exogenous surfactant as part of a complex combined therapy of patients with ARDS, which leads to decreased mortality, improved oxygenation, and decreased need for aggressive artificial pulmonary ventilation. The authors of this article present their own experience with administration of exogenous surfactant in therapy of children with ARDS.

Changes of airway obstruction parameters in healthy children caused by mother's smoking during pregnancy

The present study was aimed at the assessment of the impact of mother smoking during pregnancy on changes of phase angle (phi) and T(me)/T(E) index in healthy children. A hundred and twenty seven children, divided according to age (<6 months and >6 months of age) and mother smoking anamnesis were investigated by noncalibrated respiratory inductive plethysmography in the supine position. We found statistically significant changes of phi (p<0.05) and T(me)/T(E) in healthy children of non-smoking mothers against a group of smoking mother's children of up to 6 months of age. These differences were not confirmed in children older than 6 months. Moreover, in the smoking mother group, we found statistically significant changes (P<0.05) of phi and T(me)/T(E) in children of up to 6 months of age in comparison with children older than 6 month. The results revealed a negative impact of mother smoking during pregnancy represented by changes in airway obstruction parameters, which appeared especially in the group of youngest children.

Age-dependent changes of airway obstruction parameters

The study was aimed at the assessment of the physiological range of phi and Tme/Te indices in children of up to 24 months of age, as based on noncalibrated respiratory inductive plethysmography performed in the supine position. We also examined the dependence of these indices on children's age and sex. The study was carried out in 127 healthy children. The results of the study indicate a significant decrease of phi in children aged 7-24 months in comparison with children of up to 6 months of age (P<0.001). Similarly, values of Tme/Te were found significantly higher in the group of older children (P<0.05). We did not find any appreciable sex differences in both measured parameters. The results of this study suggest that the Tme/Te index might be more stable, less age-dependent parameter of the Respitrace measurement than the phase angle j, but further research and analysis to achieve a correct verdict are warranted.

The role of potassium ion channels in cough and other reflexes of the airways

In this study we investigated whether openers of potassium channels, K+ATP--pinacidil and BK+Ca--NS1619, modulate cough reflex and airway smooth muscle (ASM) reactivity in in vivo and in vitro conditions in guinea pigs. The cough reflex was induced by 0.3 M citric acid aerosol given for 3 min during which time a total number of coughs was counted. ASM reactivity in vivo was expressed as the values of specific airway resistance calculated by Pennock. Changes in ASM reactivity in vitro were tested by a tissue bath method. We found that both openers of potassium channels inhibit the citric acid-induced cough. ASM reactivity in vivo was significantly abolished by pinacidil and NS1619, which corresponded with the results of in vitro measurements. Pretreatment by selective blockers, K+ATP--glibenclamide and BK+Ca-tetraethylammonium prevented the above mentioned effects. The results indicate an important role of K+ATP and BK+Ca ion channels in defense reflexes of airways.

The antitussive activity of polysaccharides from Althaea officinalis l., var. Robusta, Arctium lappa L., var. Herkules, and Prunus persica L., Batsch

BACKGROUND

The therapy of pathological type of cough presents serious medical problem.

OBJECTIVES

The aim of experiments was to investigate polysaccacharide influence on experimentally induced cough.

METHODS

The purified and/or modified polysaccharides from the flowers and plants, characterized by chemical composition and molecular properties were subjected to tests for antitussive activity on cough, induced mechanically in conscious cats of both sexes.

RESULTS

The results revealed that the tested polysaccharides exhibited statistically significant cough-suppressing activity, which was noticeably higher than that of the non-narcotic drug used in clinical practice to treat coughing. The most expressive antitussive activity was observed with the polysaccharide from marsh mallow, containing the highest proportion of the uronic acid constituent. Negative influence of the tested compounds on expectoration was negligible when compared to that of codeine.

CONCLUSION

Antitussive activity of various plant polysaccharides was confirmed. These results allow ranging them among prospective antitussive agents (Tab. 2, Fig. 6, Ref. 15) Full Text (Free, PDF) www.bmj.sk.