Gold Nanoparticles Inhibit Steroid-Insensitive Asthma in Mice Preserving Histone Deacetylase 2 and NRF2 Pathways.

BACKGROUND: Gold nanoparticles (AuNPs) can inhibit pivotal pathological changes in experimental asthma, but their effect on steroid-insensitive asthma is unclear. The current study assessed the effectiveness of nebulized AuNPs in a murine model of glucocorticoid (GC)-resistant asthma. METHODS: A/J mice were sensitized and subjected to intranasal instillations of ovalbumin (OVA) once a week for nine weeks. Two weeks after starting allergen stimulations, mice were subjected to Budesonide or AuNP nebulization 1 h before stimuli. Analyses were carried out 24 h after the last provocation. RESULTS: We found that mice challenged with OVA had airway hyperreactivity, eosinophil, and neutrophil infiltrates in the lung, concomitantly with peribronchiolar fibrosis, mucus production, and pro-inflammatory cytokine generation compared to sham-challenged mice. These changes were inhibited in mice treated with AuNPs, but not Budesonide. In the GC-resistant asthmatic mice, oxidative stress was established, marked by a reduction in nuclear factor erythroid 2-related factor 2 (NRF2) levels and catalase activity, accompanied by elevated values of thiobarbituric acid reactive substances (TBARS), phosphoinositide 3-kinases δ (PI3Kδ) expression, as well as a reduction in the nuclear expression of histone deacetylase 2 (HDAC2) in the lung tissue, all of which sensitive to AuNPs but not Budesonide treatment. CONCLUSION: These findings suggest that AuNPs can improve GC-insensitive asthma by preserving HDAC2 and NRF2.

Repeated Allergen Exposure in A/J Mice Causes Steroid-Insensitive Asthma via a Defect in Glucocorticoid Receptor Bioavailability.

The importance of developing new animal models to assess the pathogenesis of glucocorticoid (GC)-insensitive asthma has been stressed. Because of the asthma-prone background of A/J mice, we hypothesized that asthma changes in these animals would be or become resistant to GCs under repeated exposures to an allergen. A/J mice were challenged with OVA for 2 or 4 consecutive d, starting on day 19 postsensitization. Oral dexamethasone or inhaled budesonide were given 1 h before challenge, and analyses were done 24 h after the last challenge. Airway hyperreactivity, leukocyte infiltration, tissue remodeling, and cytokine levels as well as phosphorylated GC receptor (p-GCR), p-GATA-3, p-p38, MAPK phosphatase-1 (MKP-1), and GC-induced leucine zipper (GILZ) levels were assessed. A/J mice subjected to two daily consecutive challenges reacted with airway hyperreactivity, subepithelial fibrosis, and marked accumulation of eosinophils in both bronchoalveolar lavage fluid and peribronchial space, all of which were clearly sensitive to dexamethasone and budesonide. Conversely, under four provocations, most of these changes were steroid resistant. A significant reduction in p-GCR/GCR ratio following 4- but not 2-d treatment was observed, as compared with untreated positive control. Accordingly, steroid efficacy to transactivate MKP-1 and GILZ and to downregulate p-p38, p-GATA-3 as well as proinflammatory cytokine levels was also seen after two but not four provocations. In conclusion, we report that repeated allergen exposure causes GC-insensitive asthma in A/J mice in a mechanism associated with decrease in GCR availability and subsequent loss of steroid capacity to modulate pivotal regulatory proteins, such as GATA-3, p-p38, MKP-1, and GILZ.

Diabetes Downregulates Allergen-Induced Airway Inflammation in Mice.

Previous studies described that allergic diseases, including asthma, occur less often than expected in patients with type 1 diabetes. Here, we investigated the influence of diabetes on allergic airway inflammation in a model of experimental asthma in mice. Diabetes was induced by intravenous injection of alloxan into 12 h-fasted A/J mice, followed by subcutaneous sensitization with ovalbumin (OVA) and aluminum hydroxide (Al(OH)3), on days 5 and 19 after diabetes induction. Animals were intranasally challenged with OVA (25 µg), from day 24 to day 26. Alloxan-induced diabetes significantly attenuated airway inflammation as attested by the lower number of total leukocytes in the bronchoalveolar lavage fluid, mainly neutrophils and eosinophils. Suppression of eosinophil infiltration in the peribronchiolar space and generation of eosinophilotactic mediators, such as CCL-11/eotaxin, CCL-3/MIP-1α, and IL-5, were noted in the lungs of diabetic sensitized mice. In parallel, reduction of airway hyperreactivity (AHR) to methacholine, mucus production, and serum IgE levels was also noted under diabetic conditions. Our findings show that alloxan diabetes caused attenuation of lung allergic inflammatory response in A/J mice, by a mechanism possibly associated with downregulation of IgE antibody production.

JM25-1, a Lidocaine Analog Combining Airway Relaxant and Antiinflammatory Properties: Implications for New Bronchospasm Therapy.

BACKGROUND: Inhaled lidocaine antagonized bronchospasm in animal models and patients, but adverse effects limited its efficacy. This study evaluated the antibronchospasm potential of the analog JM25-1, exploring in vitro mechanisms and translation to an animal model. METHODS: The effectiveness of JM25-1 was assessed in GH3 cells, rat tracheal rings, mouse lymphocytes, and human eosinophil systems in vitro, assessing changes in Na current, contraction, proliferation, and survival, respectively. Lung function and inflammatory changes were studied in ovalbumin-sensitized mice. RESULTS: The efficacy of JM25-1 was higher than lidocaine in inhibiting carbachol-induced and calcium-induced tracheal contractions (maximum effect inhibition at 1 mM [%]: 67 ± 10 [JM25-1] vs. 41 ± 11 [lidocaine] [P < 0.001] for carbachol; 100 ± 3 [JM25-1] vs. 36 ± 26 [lidocaine] [P < 0.001] for Ca; mean ± SD; n = 9 each) but lower in Na current (50% inhibitory concentration = 151.5, n = 8 vs. 0.2 mM; n = 5; P < 0.001). JM25-1 also inhibited eosinophil survival (dead cells [%]: 65 ± 6; n = 4; P < 0.001 at 1 mM) and lymphocyte proliferation (cells in phase S + G2 [%]: 94 ± 10; n = 6; P < 0.001) at 0.6 mM. Aerosolized JM25-1 (1%) decreased lung eosinophil numbers from 13.2 ± 2.4 to 1.7 ± 0.7 × 10/µm (n = 6; P < 0.001) and neutrophils from 1.9 ± 0.4 to 0.2 ± 0.1 × 10/µm (n = 7; P < 0.001). Other parameters, including airway hyperreactivity, cytokines, mucus, and extracellular matrix deposition, were also sensitive to aerosolized JM25-1. CONCLUSION: These findings highlight the potential of JM25-1, emphasizing its putative value in drug development for clinical conditions where there is bronchospasm.

Nebulized lidocaine prevents airway inflammation, peribronchial fibrosis, and mucus production in a murine model of asthma.

BACKGROUND: Evidence suggests that nebulized lidocaine is beneficial in asthma therapy, but to what extent and the mechanisms underlying this effect remain poorly understood. The aim of this study was to assess the impact of lidocaine treatment using a murine model of allergic asthma characterized by expression of pivotal features of the disease: inflammation, mucus production, and lung remodeling. METHODS: A/J mice sensitized with ovalbumin were treated with inhaled lidocaine or vehicle immediately after ovalbumin intranasal challenges. Lung function, total and differential leukocytes in bronchoalveolar lavage fluid, peribronchial eosinophil density, interleukin (IL)-4, IL-5 and eotaxin-1 levels, epithelial mucus, collagen, extracellular-matrix deposition, matrix metalloproteinase-9 activity, and GATA-3 expression were evaluated. Between five and eight animals per group were used. RESULTS: Inhaled lidocaine inhibited ovalbumin-induced airway hyperreactivity to methacholine, and accumulation of lymphocytes, neutrophils, and eosinophils in bronchoalveolar lavage fluid 24 h after the last allergen provocation. Lidocaine administration also prevented other pathophysiological changes triggered by ovalbumin in lung tissue, including peribronchial eosinophil and neutrophil infiltration, subepithelial fibrosis, increased content of collagen and mucus, matrix metalloproteinase-9 activity, and increased levels of IL-4, IL-5, IL-13, and eotaxin-1. Furthermore, inhaled lidocaine inhibited lung tissue GATA-3 expression in ovalbumin-challenged mice. We also demonstrated that lidocaine inhibited the expression of GATA-3 in ovalbumin-stimulated T cells in vitro. CONCLUSIONS: Inhaled lidocaine prevents eosinophilic inflammation, overproduction of mucus, and peribronchial fibrosis in a murine model of asthma, and impaired airway hyperreactivity, possibly by inhibiting allergen-evoked GATA-3 expression and the subsequent up-regulation of proinflammatory cytokines and chemokines.

Aldose reductase inhibitor zopolrestat restores allergic hyporesponsiveness in alloxan-diabetic rats.

This study was undertaken to investigate the role of the aldose reductase in the refractoriness of diabetic rats to allergic inflammation. Wistar rats were actively sensitized with a mixture of Al(OH)3 plus ovalbumin and intrapleurally challenged with ovalbumin, 14 days later. Diabetes was induced by intravenous injection of alloxan into fasted rats, 7 days before sensitization, and the aldose reductase inhibitor zopolrestat was administered after 3 days of diabetes induction, once a day during 18 consecutive days. The treatment with zopolrestat restored antigen-induced protein extravazation and mast cell degranulation in the pleural cavity of diabetic sensitized rats. Zopolrestat also significantly reversed the suppression in the increase of total and specific levels of serum immunoglobulin E (IgE) noted in sensitized animals under conditions of diabetes. In addition, we noted that the drop in the pleural mast cell numbers as well as the increase in serum corticosterone levels in diabetic rats were inhibited by the drug. Our findings show that zopolrestat restored the hyporesponsiveness of diabetic rats to antigen provocation, in parallel with impairment of alloxan-induced mast cell depletion and hypercorticolism, indicating that polyol pathway activity seems to play an important role in these phenomena.

Local anaesthetic medication for the treatment of asthma.

It is presumed that drugs able to prevent bronchial spasm and/or inflammation may have therapeutic potential to control asthma symptoms. The local anaesthetic lidocaine has recently received increased attention as an alternative form of treatment for asthmatic patients. This paper reviews the major findings on the topic and summarizes the putative mechanisms underlying the airway effects of local anaesthetic agents. We think that lidocaine extends the spectrum of options in asthma therapy, probably by counteracting both spasmogenic and inflammatory stimuli in the bronchial airways. The possibility of development of new anti-asthma compounds based on the synthesis of lidocaine derivatives is also on the horizon.

Local anaesthetic medication for the treatment of asthma

It is presumed that drugs able to prevent bronchial spasm and/or inflammation may have therapeutic potential to control asthma symptoms. The local anaesthetic lidocaine has recently received increased attention as an alternative form of treatment for asthmatic patients. This paper reviews the major findings on the topic and summarizes the putative mechanisms underlying the airway effects of local anaesthetic agents. We think that lidocaine extends the spectrum of options in asthma therapy, probably by counteracting both spasmogenic and inflammatory stimuli in the bronchial airways. The possibility of development of new anti-asthma compounds based on the synthesis of lidocaine derivatives is also on the horizon.

Systemic anaphylaxis is prevented in alloxan-diabetic rats by a mechanism dependent on glucocorticoids.

This study was undertaken to examine whether glucocorticoids could be implicated in the hyporesponsiveness of diabetic rats to systemic anaphylaxis. Rats were actively sensitized with a mixture of Al(OH)(3) plus ovalbumin and challenged i.v. with ovalbumin 14 days later. Diabetes was induced by alloxan-injected i.v. either before or after sensitization. Elevation of total and specific serum immunoglobulin E (IgE) was abolished in rats turned diabetic and then sensitised, but not in those first sensitised and then turned diabetic. In both conditions, increased serum corticosterone levels occurred in parallel with protection of diabetic animals against fatal shock, intestinal haemorrhage and elevation in plasma histamine levels evoked by antigen challenge. The resistance of diabetic rats to fatal shock was no longer significantly different from that of non-diabetic rats following treatment with the glucocorticoid receptor antagonist RU 486 (mifepristone). These findings indicate that endogenous glucocorticoid plays a pivotal role in the phenomenon of hyporeactivity to systemic anaphylaxis in alloxan-diabetic rats.

Antigen-induced pleural eosinophilia is suppressed in diabetic rats: role of corticosteroid hormones

Previous studies have evidenced for the existence of interactive regulatory mechanisms between insulin and steroid hormones in different systems. In this study, we have investigated whether endogenous corticosteroids could be implicated in the hyporeactivity to antigen challenge observed in sensitized diabetic rats. Alloxinated rats showed a long-lasting increase in the blood glucose levels and a reduction in the number of pleural mast cells at 48 and 72 hr, but not at 24 hr after alloxan administration. In parallel, they also showed a significant elevation in the plasma levels of corticosterone together with an increase in the adrenal/body weight ratio. Antigen-evoked eosinophil accumulation appeared significantly reduced in rats pretreated with dexamethasone as weel as in those rendered diabetic 72 hr after alloxan. In the same way, naive animals treated with dexamethasone also responded with a significant decrease in the number of pleural mast cells. Interestingly, when sensitized diabetic rats were pretreated with the steroid antagonist RU 38486 a reversion of the reduction in the allergen-induced eosinophil accumulation was noted. We conclude that the down-regulation of the allergic inflammatory response in diabetic rats is close-related to reduction in mast cell numbers and over expression of endogenous corticosteroids.