Applicability of an ultrasonic nebulization system for the airways delivery of beclomethasone dipropionate in a murine model of asthma

Effect of Agmatine on a mouse model of allergic airway inflammation: A comparative study

INTRODUCTION

Asthma is a chronic lung disease that injures and constricts the airways. This study evaluates the effects of agmatine on ovalbumin (OVA)-induced allergic inflammation of the airways.

METHODS

OVA sensitization by intraperitoneal injection was used to induce airway inflammation in mice on days 0 and 7; then the mice were challenged using beclomethasone (150 µg/kg, inhalation), a standard anti-asthmatic drug, from day 14 to day 16. Furthermore, agmatine (200 mg/kg) was intraperitoneally injected on day 0 and then daily for 16 days, followed by OVA challenge. The lung weight ratio, total and differential cell counts, TNF-α, interleukin-5 (IL-5) and IL-13 in bronchoalveolar lavage fluid (BALF), lung nitrite/nitrate (NO), and oxidative parameters were determined. Moreover, histopathological and immunohistochemical staining was employed.

RESULTS

Injection of agmatine (200 mg/kg) for 16 days significantly attenuated inflammation of the airways. The levels of BALF inflammatory cells, TNF-α, IL-5, IL-13, lung NO, and malondialdehyde (MDA), significantly decreased with concomitant elevation of superoxide dismutase (SOD) levels. Histological and immunohistochemical analyses of mast cells paralleled to biochemical improvements.

CONCLUSION

Finally, this study illustrated that agmatine attenuates the allergic inflammation of airways caused by OVA by mitigating cytokines release, NO expression, and oxidative stress.

Essential role of smooth muscle Rac1 in severe asthma-associated airway remodelling

Background

Severe asthma is a chronic lung disease characterised by inflammation, airway hyperresponsiveness (AHR) and airway remodelling. The molecular mechanisms underlying uncontrolled airway smooth muscle cell (aSMC) proliferation involved in pulmonary remodelling are still largely unknown. Small G proteins of the Rho family (RhoA, Rac1 and Cdc42) are key regulators of smooth muscle functions and we recently demonstrated that Rac1 is activated in aSMC from allergic mice. The objective of this study was to assess the role of Rac1 in severe asthma-associated airway remodelling.

Methods and results

Immunofluorescence analysis in human bronchial biopsies revealed an increased Rac1 activity in aSMC from patients with severe asthma compared with control subjects. Inhibition of Rac1 by EHT1864 showed that Rac1 signalling controlled human aSMC proliferation induced by mitogenic stimuli through the signal transducer and activator of transcription 3 (STAT3) signalling pathway. In vivo, specific deletion of Rac1 in SMC or pharmacological inhibition of Rac1 by nebulisation of NSC23766 prevented AHR and aSMC hyperplasia in a mouse model of severe asthma. Moreover, the Rac1 inhibitor prevented goblet cell hyperplasia and epithelial cell hypertrophy whereas treatment with corticosteroids had less effect. Nebulisation of NSC23766 also decreased eosinophil accumulation in the bronchoalveolar lavage of asthmatic mice.

Conclusion

This study demonstrates that Rac1 is overactive in the airways of patients with severe asthma and is essential for aSMC proliferation. It also provides evidence that Rac1 is causally involved in AHR and airway remodelling. Rac1 may represent as an interesting target for treating both AHR and airway remodelling of patients with severe asthma.

Flavocoxid attenuates airway inflammation in ovalbumin-induced mouse asthma model

Asthma is a common airways inflammatory disease. This study provides evidence on the efficacy of flavocoxid against ovalbumin (OVA)-induced allergic airways inflammation in a mouse model of asthma. Airway inflammation was induced by intrapеritonеal injection of 10 mg ovalbumin (OVA) on day zero and day 7 followed by OVA challenge starting from 14th day to 16th day. Beclomethasone; a standard anti-inflammatory agent was selected as a drug in asthma. Flavocoxid (20 mg/kg, i. p.) was administered on day zero till 16th day followed by OVA challenge. At the end of the study, lung weight index, bronchoalveolar lavage fluid (BALF) content of total and differential WBCs, interleukin-13(IL-13), in addition to lung tissue nitrate/nitrite (NO) and oxidative stress biomarkers were measured. Also, histological and immunohistochemical analysis were conducted. Daily i. p. injection of flavocoxid (20 mg/kg) significantly improved airway inflammation. Inflammatory cells in BALF, malondialdehyde (MDA), NO and IL-13 significantly declined with concomitant increase in superoxide dismutase (SOD) activity. Histopathological examination and immunohistochеmical staining of mast cells were correlated with observed biochemical improvements. Collectively, these results demonstrate that flavocoxid mitigates the allergic airway inflammation induced by ovalbumin through attenuation of IL-13, NO expressions and oxidative stress.

Protective efficacy of inhaled quercetin for radiation pneumonitis

Radiation pneumonitis is a clinical problem with a high incidence. Once the onset of radiation pneumonitis has occurred, the administration of antioxidants and anti-inflammatory agents is the most commonly used method of clinical treatment. Quercetin (Que) is a common flavonoid, with potent anti-inflammatory and anti-oxidant activities. In the present study, the therapeutic effect of inhaled Que on radiation-induced radiation pneumonitis in rats was investigated. Treatment with Que via inhalation was shown to increase the number of leukocytes and erythrocytes in the blood, and reduce the number of inflammatory cells in bronchoalveolar lavage fluid. Histological examination of lung tissue indicated that inhaled Que reduced hemorrhaging and the infiltration of inflammatory cells, and suppressed the expression of the proinflammatory cytokines transforming growth factor-β₁ and interleukin-6. These results indicated that treatment with Que via inhalation ameliorates radiation pneumonitis by reducing the number of inflammatory cells, and attenuating the inflammatory response and pathological changes. This suggests that administration of Que via inhalation has the potential to become a novel treatment for radiation pneumonitis.

Effect of tranilast in comparison with beclomethasone in chronic murine model of asthma

AIM OF THE STUDY

The current investigation was taken to scrutinize the action of tranilast on the airway remodeling in chronic asthma in mice.

MATERIALS AND METHODS

Intraperitoneal injection of ovalbumin was applied to mice for sensitization and subsequent inhalation of 1% ovalbumin three times week for 10 weeks for challenge. Beclomethasone or tranilast were given daily for the 10 week challenge period. At the end of the study, lung weight index, total collagen content, bronchoalveolar lavage level of total and differential cell counts, interleukin-13, in addition to lung tissue nitrate/nitrite and transforming growth beta-1 were measured. Also, histological analysis was done.

RESULTS

Asthmatic mice demonstrated apparent fibrotic changes. Significant airway fibrosis was demonstrated by hyperplasia of goblet cells and thickening of airway epithelium, increased content of lung collagen, lung and bronchoalveolar lavage of transforming growth factor beta-1 and interleukin-13 mutually accompanied by reduction in nitrate/nitrite generation.

CONCLUSIONS

Beclomethasone influence on airway remodeling was mediated mainly via suppression of eosinophilic recruitment into the airways and reduction of interleukin-13 cytokine levels. Whereas, tranilast effects on airway remodeling was found to be mainly mediated via its inhibitory effect on transforming growth beta-1. Both beclomethasone and tranilast influence airway remodeling by different degrees and mechanisms.

Further experimentation of inhaled; LANTUS, ACTRAPID and HUMULIN with todays' production systems

BACKGROUND

Several aerosol production systems have been used for aerosol insulin production. However; since the first studies several new models of jet-nebulizers and ultrasound nebulizers have been introduced in the market.

MATERIALS AND METHODS

Three different models of jet-nebulizers (different brands, same properties) and three different ultrasound nebulizers (different brands, same properties). Six residual cups (2 small ≤ 6 ml and 3 large ≤ 8 ml) were used for the jet-nebulizers. The ultrasound nebulizers were used with their facemasks or with their inlets which were included in the purchase package.

RESULTS

Ultrasound nebulizers; LANTUS produces by far the lowest mean droplets (2.44) half the size of the other two drugs (4.43=4.97). GIMA nebulizer is the most efficient producing one third of the droplet size of SHIMED and one second of EASYNEB (2.06<3.15<6.62). Finally, the 4 ml loading concentration is more suitable for supporting the production of smaller droplets (3.65<4.24). Drugs and nebulizers act interactively yielding very large droplets when ACTRAPID and HUMULIN are administered in joint with SHIMED nebulizer (9.59=7.72). Jet-nebulizers; HUMULIN again is the least preferred insulin since it hardly reaches the low but equal performance of others at the loading level of 6 ml. Residual cups E and B produce uniquely lower mean droplets at loading level 6.

CONCLUSIONS

Ultrasound nebulizers; the best suggested combination should be LANTUS insulin, GIMA nebulizer administered at loading dose of 4 ml jet-nebulizers. A global review can give the best combination: the lowest mean droplets are produced when the drugs LANTUS (mostly) and ACTRAPID are administered, applying the SUNMIST nebulizer in concert with residual cup B at loading levels of 6 ml.

Visualization of murine intranasal dosing efficiency using luminescent Francisella tularensis: effect of instillation volume and form of anesthesia

Intranasal instillation is a widely used procedure for pneumonic delivery of drugs, vaccine candidates, or infectious agents into the respiratory tract of research mice. However, there is a paucity of published literature describing the efficiency of this delivery technique. In this report we have used the murine model of tularemia, with Francisella tularensis live vaccine strain (FTLVS) infection, to evaluate the efficiency of pneumonic delivery via intranasal dosing performed either with differing instillation volumes or different types of anesthesia. FTLVS was rendered luminescent via transformation with a reporter plasmid that constitutively expressed the Photorhabdus luminescens lux operon from a Francisella promoter. We then used an IVIS Spectrum whole animal imaging system to visualize FT dissemination at various time points following intranasal instillation. We found that instillation of FT in a dose volume of 10 µl routinely resulted in infection of the upper airways but failed to initiate infection of the pulmonary compartment. Efficient delivery of FT into the lungs via intranasal instillation required a dose volume of 50 µl or more. These studies also demonstrated that intranasal instillation was significantly more efficient for pneumonic delivery of FTLVS in mice that had been anesthetized with inhaled (isoflurane) vs. parenteral (ketamine/xylazine) anesthesia. The collective results underscore the need for researchers to consider both the dose volume and the anesthesia type when either performing pneumonic delivery via intranasal instillation, or when comparing studies that employed this technique.

Influence of inhaled beclomethasone and montelukast on airway remodeling in mice

This study examined the effect of montelukast and beclomethasone on airway remodeling in murine model of asthma. Mice were sensitized by i.p. injection of ovalbumin (OVA) on days 0 and 14, and then challenged by nebulization of 1% OVA 3 days/week for 6 or 10 weeks. Results of 6-week OVA-challenged group showed moderate inflammation, but the 10-week OVA-challenged group exhibited mild inflammation. The OVA challenge (6 and 10 weeks) exhibited marked airway fibrosis, illustrated by significant increase in goblet cell hyperplasia and epithelial thickness, increased lung content of collagen and transforming growth factor-β(1), together with a decrease in nitric oxide production; also, there was an increase in bronchoalveolar lavage fluid level of interleukin-13. Administration of montelukast or beclomethasone before each OVA challenge was capable of restoring most of the measured parameters to near normal levels. Inhalation of beclomethasone has a similar role in airway remodeling as montelukast, but its effects in regulating inflammatory changes is less pronounced than montelukast.

Generating Nanoparticles for Respiratory Drug Delivery

Generating liquid droplets is ideal for many applications including respiratory drug delivery because the droplets have uniform properties and can be easily controlled, sampled, and analyzed. In this study, a micropump-based droplet generator is proposed to produce the liquid droplets of micron to nano size. Numerical simulations were carried out to evaluate the ability of the proposed droplet generator device to produce liquid droplets. The velocity and diameter of the droplets generated by the droplet generator device were calculated, and the performance of the device’s flow rate and power consumption was evaluated. The effects of actuation frequency, actuation modes, and nozzle geometry on the performance of the device were investigated. Results showed that the proposed device can produce micron-/nano-sized liquid droplets with low power and the advantages of the proposed droplet generator device over traditional devices were discussed.

Cage enrichment with paper tissue, but not plastic tunnels, increases variability in mouse model of asthma

Environmental enrichment, besides having a great impact on animal welfare, can also be a potential variable in experimental research. Thus, we investigated whether enrichment of cages with paper tissues or plastic tunnels affects scientific outcome in the well-described mouse model of allergic asthma. BALB/cJ mice were introduced to paper tissues as nesting material, transparent plastic tunnels serving as shelters or kept in non-enriched cages. Afterwards, mice were sensitized to chicken egg ovalbumin (OVA) precipitated in aluminium sulphate and then intranasally challenged with OVA to induce allergic lung inflammation. Mice housed in cages enriched with paper tissues, but not with plastic tunnels, had increased total cell number, eosinophil number and IL-13 concentration in bronchoalveolar lavage fluid in comparison with the non-enriched control group. These results indicate that the effect of environmental enrichment on mice asthma models depends on the type of enrichment used. Therefore, it is important to consider the potential effects of any environmental enrichment on animal welfare and more importantly, on research results in order to standardize and obtain more accurate data from rodent studies.

Clarithromycin suppresses airway hyperresponsiveness and inflammation in mouse models of asthma

Macrolide antibiotics, a class of potent antimicrobials, also possess immunomodulatory/anti-inflammatory properties. These properties are considered fundamental for the efficacy of macrolide antibiotics in the treatment of diffuse panbronchiolitis and cystic fibrosis. In patients with asthma, macrolide antibiotics have been reported to reduce airway hyperresponsiveness and improve pulmonary function. However, their beneficial actions in asthmatics possibly could be attributed to antimicrobial activity against atypical pathogens (e.g. Chlamydia pneumoniae), corticosteroid-sparing effect (inhibition of exogenous corticosteroid metabolism), and/or their anti-inflammatory/immunomodulatory effects. In order to investigate whether efficacy of macrolide antibiotics in asthma results from their immunomodulatory/anti-inflammatory activity, the influence of clarithromycin pretreatment (2 h before challenge) was examined on ovalbumin-induced airway hyperresponsiveness and airway inflammation in the mouse. Clarithromycin treatment (200 mg/kg intraperitoneally) decreased IL-4, IL-5, IL-13, CXCL2 and CCL2 concentrations in bronchoalveolar lavage fluid and markedly reduced inflammatory cell accumulation in bronchoalveolar lavage fluid and into the lungs, as revealed by histopathological examination. Furthermore, clarithromycin-induced reduction in inflammation was accompanied by normalization of airway hyperresponsiveness. In summary, in ovalbumin-induced mouse models, clarithromycin efficiently inhibited two important pathological characteristics of asthma, airway hyperresponsiveness and inflammation. These data suggest that the efficacy of clarithromycin, as well as of other macrolide antibiotics, in asthmatic patients could be attributed to their anti-inflammatory/immunomodulatory properties, and not only to their antimicrobial activity or exogenous corticosteroid-sparing effects.