Oral administration of allergen extracts from Dermatophagoides farinae desensitizes specific allergen-induced inflammation and airway hyperresponsiveness in rats

Fetal loss due to Th1-skewed Th1/Th2 balance with increase (not decrease) of regulatory T cells in abortion-prone mouse model

We used an abortion-prone mouse model, generated by mating female CBA/J mice with male DBA/2JJcl mice, to examine the effects of changes in the Th1/Th2 cell ratio and the percentage of regulatory T (Treg) cells on the maintenance of pregnancy. We subcutaneously injected female CBA/J mice once each with 50 μg/mouse of Dermatophagoides farinae (Df) extract and the squalene-based adjuvant (SquA); 10 days later, these mice were mated with male DBA/2JJcl mice. Compared with injection of vehicle or adjuvant, the Df treatment decreased the Th1/Th2 cell ratio and concomitantly increased the percentage of Treg cells in the spleen. In addition, fetal death rates were decreased. We then explored a substance which shifted the Th1/Th2 balance toward Th1 side. We found that 50 μg/mouse of keyhole limpet hemocyanin (KLH) increased the splenic Th1/Th2 cell ratio of nonpregnant female CBA/J mice. We subcutaneously injected female CBA/J mice with KLH and SquA; 10 days later, these mice were mated with male DBA/2JJcl mice. Compared with injection of vehicle or adjuvant, treatment with KLH enhanced the Th1 bias during pregnancy and increased the fetal death rate. The percentage of Treg cells, however, was increased in these KLH-injected pregnant mice contrary to our presumption. All collected data showed strong positive correlation between the Th1/Th2 cell ratio and fetal death rate. The increase in Treg cells independent of effects on the fetal death rate suggests that Treg cells do not necessarily induce maternal tolerance to the fetus but may prevent excessive Th1/Th2 imbalance during pregnancy.

Dapagliflozin mitigates ovalbumin-prompted airway inflammatory-oxidative successions and associated bronchospasm in a rat model of allergic asthma

BACKGROUND

Asthma is a chronic inflammatory lung disease that universally affects millions of people. Despite numerous well-defined medications, asthma is poorly managed. The study aimed to clarify the potential therapeutic effect of Dapagliflozin (DAPA) against lung inflammation, oxidative stress and associated bronchospasm in OVA-sensitized rat asthma model.

RESEARCH DESIGN AND METHODS

Twenty-five rats were allocated into (Control, Asthma, DEXA, DAPA, and DAPA+DEXA). All treatments were administered orally once a day for two weeks. BALF levels of IL-17, TNFα, IL-1β, and MCP-1 were determined to assess airway inflammation. For oxidative stress determination, BALF MDA levels and TAC were measured. The BALF S100A4 level and NO/sGC/cGMP pathway were detected. Lung histopathological findings and immunohistochemical investigation of eNOS and iNOS activities were recorded.

RESULTS

DAPA significantly reduced (p < 0.001) airway inflammatory-oxidative markers (IL-17, TNFα, IL-1β, MCP1, and MDA), but increased (p < 0.001) TAC, and mitigated bronchospasm by activating NO/sGC/cGMP and reducing S100A4 (p < 0.001). The biochemical and western blot studies were supported by histopathological and immunohistochemical investigations.

CONCLUSIONS

: DAPA is presenting a new prospective possibility for future asthma therapy due to its anti-inflammatory, anti-oxidant, and bronchodilator properties. DAPA has the property of reducing Dexamethasone (DEXA)-associated unfavorable effects during asthma treatment.

Immunomodulatory and anti-inflammatory effects of N-acetylcysteine in ovalbumin-sensitized rats

Background

Pro-inflammatory cytokines such as interleukin-5 (IL-5) and tumor necrosis factor-alpha (TNF-α) as well as immunoglobulin-E (IgE) appear to play a role in asthma. N-acetylcysteine (NAC), an antioxidant, might have clinical benefits in asthma prevention. The possible preventive effects of NAC against experimentally induced asthma in rats are investigated. The rats were allocated into five groups: a normal control, asthma control, a standard dexamethasone (DEXA, 1 mg/kg, orally) group, and two NAC groups (300 and 500 mg/kg, orally, respectively). Ovalbumin (OVA) sensitization was used to trigger asthma, which was then followed by an intra-nasal challenge. Test gents were administrated for 14 days before the challenge and during the three challenge days (20, 21, and 22). The tidal volume (TV) and peak expiratory flow rate (PEFR) as respiratory functions were determined. The pro-inflammatory cytokines as IL-5 and TNF-α were evaluated in lung homogenate. Serum IgE and absolute eosinophil count (AEC) in bronchoalveolar lavage fluid (BALF) were measured. In addition, the oxidative markers in lung tissue and nitrosative marker in BALF were assessed; finally, lungs were isolated for histopathological study.

Results

NAC restored lung functions, inhibited the asthma-dependent increase in TNF-α, IL-5, IgE, AEC, nitric oxide, and malondialdehyde levels. NAC further re-established lung glutathione content and superoxide dismutase activity, resulting in milder overall lung pathology.

Conclusions

Experimental bronchial asthma may be protected by NAC. The anti-asthmatic potential of NAC may be explained by its suppressant influence on IgE antibody formation, pro-inflammatory cytokines production, eosinophil infiltration, and oxidative stress.

Allergic Inflammation Alters microRNA Expression Profile in Adipose Tissue in the Rat

Adipose tissue is a major source of circulating exosomal microRNAs (miRNAs) that are modulators of the immune response in various types of tissues and organs, including airways. Still, no evidence exists if allergic airway inflammation may affect fat tissue inflammation via alterations in the miRNA expression profile. Therefore, we investigated the miRNA expression profile in the adipose tissue upon induced allergic inflammation in the airways in the rat. Brown Norway rats were chronically sensitized to house dust mite extract for seven weeks. Body composition was performed using MiniSpec Plus. The eosinophil count and the total IgE level were determined to confirm the induction of allergic inflammation. MiRNA expression profiling was done using the next-generation sequencing with validation by qPCR. We found that allergic airway inflammation significantly increased fat in adipose tissue, glucose concentration, and the gene expression of adipose tissue-derived proinflammatory peptides (leptin, TNFα). In miRNA-seq analysis, we showed significant differences in the expression of 36 mature miRNAs, three precursors, and two miRNA families in adipose tissue of allergic rats. Two miRNAs—miRNA-151-5p and miRNA-423-3p—showed significantly increased expression in qPCR in adipose tissue and lungs of sensitized animals. Allergic airway inflammation affects fat tissue and alters miRNA expression profile in adipose tissue in the rat.

Potential anti-inflammatory and immunomodulatory effects of carvacrol against ovalbumin-induced asthma in rats

BACKGROUND

Asthma is a complex inflammatory disease which affects multiple individuals worldwide especially pediatric ages.

AIMS

This study aimed to assess the possible protective effect of carvacrol, as natural antioxidant anti-inflammatory drug, against bronchial asthma induced experimentally in rats.

MAIN METHODS

Rats were randomly allocated into 5 groups; a normal control group, control drug group received only carvacrol, an asthma control group, a standard treatment group receiving dexamethasone (DEXA) and carvacrol treatment group. Bronchial asthma was induced by sensitization with i.p dose followed by challenge with intranasal dose of ovalbumin (OVA). 24 h after the last challenge, absolute eosinophil count (AEC) were determined in bronchoalveolar lavage fluids (BALF). Immunoglobulin E (IgE) was determined in serum. Inflammatory biomarkers like Interleukin-4 (IL-4), interleukin-5 (IL-5), interleukin 13 (IL-13), tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) were also measured in BALF. Nitrosative stress biomarker namely inducible nitric oxide synthase (iNOS) was determined in BALF as well as oxidative stress biomarkers namely superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA) were determined in lung tissue. Additionally, histopathological study, immunohistochemical study of UCN and western blot analysis of SP-D were performed.

KEY FINDINGS

Carvacrol administration significantly reduced the values of AEC, IgE, IL-4, IL-5, IL-13, TNF-α, IFN-γ, iNOS and MDA, while it significantly increased the values of SOD and GSH as compared to the asthmatic group. Histopathological, immunohistochemical and western blot study reinforced the biochemical results.

SIGNIFICANCE

Carvacrol may be a promising protective agent against bronchial asthma induced experimentally in rats.

Fluoxetine protects against OVA induced bronchial asthma and depression in rats

Depression is very common in asthmatic patients and may increases risk for morbidity and mortality. The present work aimed to investigate the protective effect of fluoxetine, on behavioral and biochemical changes, associated with ovalbumin (OVA) - induced bronchial asthma and depression in rats. Rats were sensitized with intraperitoneal administration of OVA plus aluminum hydroxide for 3 consecutive days then at day 11 followed by OVA intranasal challenge at days 19, 20, 21. Rats were either pretreated with dexamethasone, fluoxetine10mg/kg or fluoxetine 20 mg/kg. At the end of the experiment, various tests were performed, including open field, forced swimming and respiratory function tests. Blood was drawn for serum IgE detection. Finally, rats were euthanized, brain-derived neurotrophic factor (BDNF) was estimated in bronchoalveolar lavage (BAL) fluid and lung content of reduced glutathione (GSH), superoxide dismutase (SOD), tumor necrosis factor-alpha (TNF-α) and interleukin 4 (IL-4) were determined. Histopathological study was also performed. The results showed that fluoxetine significantly ameliorated OVA- induced biochemical and behavioral changes. Fluoxetine may protect against OVA-induced asthma and depression in rats. This effect may be mediated at least in part by its antioxidant, anti-inflammatory and immunosuppressant effect.

The potential effect of the angiotensin II receptor blocker telmisartan in regulating OVA-induced airway remodeling in experimental rats

BACKGROUND

Bronchial asthma is a true ascending clinical problem. Angiotensin II is now accused to be potentially implicated in its pathogenesis, being a potent pro-inflammatory mediator with remodeling effects.

OBJECTIVE

This study aims to evaluate the possible protective effect of telmisartan, an angiotensin II receptor blocker, on experimentally-induced bronchial asthma.

METHODS

Animals were divided into 5 groups; a normal control group, an asthma control group, a reference treatment group, receiving dexamethasone, and two treatment groups, receiving telmisartan in two dose levels. Bronchial asthma was induced by intraperitoneal sensitization followed by intranasal challenge with ovalbumin (OVA). Test agents were administered prior to each intranasal OVA challenge. Lung function tests, namely tidal volume (TV) and peak expiratory flow rate (PEF) were assessed 1h after the last challenge. One day after the last challenge, absolute eosinophil counts (AEC) in blood and bronchoalveolar lavage fluids (BALF) were assessed. Serum immunoglobulin E (IgE) as well as BALF total nitrate/nitrite (NOx) were assessed. Oxidative and inflammatory biomarkers, namely lung tissue superoxide dismutase (SOD), glutathione reduced (GSH), tumor necrosis factor-alpha (TNF-α) and interleukin-5 (IL-5), were also assessed, in addition to histopathological study.

RESULTS

Telmisartan administration in both doses significantly improved TV, PEF, AEC, IgE, NOx, GSH, SOD, TNF-α and IL-5 values compared to asthma control values. Histopathological study strongly supported the results of biochemical estimations, particularly regarding airway remodeling.

CONCLUSION

These results suggest that telmisartan may have potential protecting effects against experimental bronchial asthma, probably due to its bronchodilator, antioxidant and anti-inflammatory effects.

Production of egg yolk antibodies specific to house dust mite proteins

PURPOSE

House dust mites (HDMs) are an important source of indoor allergens associated with asthma, rhinitis and atopic dermatitis. Chicken immunoglobulin (Ig) Y is known to be a good alternative to mice and rabbit antibody production. In this study, we produced IgYs specific to HDMs and investigated their IgE immunoreactivities.

MATERIALS AND METHODS

Total IgYs were isolated from the yolks of White Leghorn hens immunized with either Dermatophagoides pteronyssinus or D. farinae protein extract. Control antibodies were separated from the yolks of immunized hens with phosphate buffered saline. IgYs specific to HDMs were analyzed using enzyme-linked immunosorbent assay and Western blotting analysis.

RESULTS

The concentration of egg IgY specific to D. farinae in an immunized hen increased and the highest achieved was 661.3 ug/mg (per an egg) on day 47, compared with 760 ug/mg IgY specific to D. pteronyssinus on day 16. The D. pteronyssinus or D. farinae-specific IgY was detected by binding of each mite proteins, and their immunoreactivities were elevated dependent of the specific IgY concentration.

CONCLUSION

IgY specific to HDMs may be a promising antibody for immunological diagnosis as well as identification of possible resistance relating to HDM allergy.

Simvastatin delivery via inhalation attenuates airway inflammation in a murine model of asthma

The dose-response of the pleiotropic effects of statins on airway inflammation has not yet been established and may differ from that of their cholesterol-lowering effects. High oral doses of statins may have adverse effects, and it may be possible to overcome the side effects and low clinical efficacy by administering statins via inhalation. In this study, we hypothesize that simvastatin is a potential anti-inflammatory drug with biological and pharmacokinetic properties suitable for delivery by the inhaled route. Mice were immunized with ovalbumin (OVA) and then challenged with aerosol OVA. Simvastatin was locally delivered by inhalation (i.h.) and intratracheal injection (i.t.) or systematically delivered by intraperitoneal injection (i.p.) and gavage (i.g.) during the OVA challenge. In a mouse model of asthma, i.h. simvastatin significantly and dose-dependently attenuated airway inflammation, remodeling and hyperresponsiveness in a RhoA-dependent pathway. Upon comparing the pharmacodynamics, i.h. simvastatin had a more potent effect than that of i.g. and i.p. simvastatin, and the i.h. or i.t. delivery routes led to a higher drug concentration in local lung tissue and a lower drug concentration in the plasma than that obtained by the i.g. These results suggest that simvastatin is a potential anti-inflammatory drug for airway inflammatory diseases with properties suitable for delivery by inhalation, which will probably reduce the side effects and increase clinical efficacy.

Oral administration of allergen extracts from mugwort pollen desensitizes specific allergen-induced allergy in mice

Clinically, sublingual immunotherapy (SLIT) using allergen extracts effectively alleviates the symptoms of allergic rhinitis and asthma. We hypothesized that oral administration of a high-dose of allergen extracts imitates SLIT, which may prevent IgE-related responses in allergic diseases. In the present study, we investigated the effects of oral administration of allergen extracts from mugwort pollen (MP) on allergen-induced inflammation and airway hyperresponsiveness (AHR) in an allergic mouse model. After administration of MPdrop containing Art v 1 and Art v 4 extracts derived from MP specifically in MP-sensitized mice, the effects of MPdrop on AHR, inflammatory cell accumulation, cytokine production in the bronchoalveolar lavage fluid and lung tissue, and serum IgE and IgG levels were investigated. The results indicated that MPdrop not only prevented the AHR in response to methacholine in a dose-dependent manner but also significantly reduced the total serum and allergen-specific IgE levels. All of the maximal effects were achieved at a dose of 100μg/(kgd) and were comparable to the effects of dexamethasone at a dose of 0.5mg/(kgd). Furthermore, oral administration of MPdrop dose-dependently elevated allergen-specific serum IgG2a levels, reduced total and allergen-specific IgE levels and normalized the imbalance between the Th1 cytokine IL-12 and Th2 cytokines IL-4 and IL-5. Finally, oral administration of MPdrop significantly reduced goblet cell hyperplasia and eosinophilia in the MP-sensitized allergic mouse model. These data suggest that MPdrop effectively improves specific allergen-induced inflammation and AHR in MP-sensitized and -challenged mice and provides the rationale for clinical use of MPdrop in the specific allergen-induced asthma.

Strategies of mucosal immunotherapy for allergic diseases

Incidences of allergic disease have recently increased worldwide. Allergen-specific immunotherapy (SIT) has long been a controversial treatment for allergic diseases. Although beneficial effects on clinically relevant outcomes have been demonstrated in clinical trials by subcutaneous immunotherapy (SCIT), there remains a risk of severe and sometimes fatal anaphylaxis. Mucosal immunotherapy is one advantageous choice because of its non-injection routes of administration and lower side-effect profile. This study reviews recent progress in mucosal immunotherapy for allergic diseases. Administration routes, antigen quality and quantity, and adjuvants used are major considerations in this field. Also, direct uses of unique probiotics, or specific cytokines, have been discussed. Furthermore, some researchers have reported new therapeutic ideas that combine two or more strategies. The most important strategy for development of mucosal therapies for allergic diseases is the improvement of antigen formulation, which includes continuous searching for efficient adjuvants, collecting more information about dominant T-cell epitopes of allergens, and having the proper combination of each. In clinics, when compared to other mucosal routes, sublingual immunotherapy (SLIT) is a preferred choice for therapeutic administration, although local and systemic side effects have been reported. Additionally, not every allergen has the same beneficial effect. Further studies are needed to determine the benefits of mucosal immunotherapy for different allergic diseases after comparison of the different administration routes in children and adults. Data collected from large, well-designed, double-blind, placebo-controlled, and randomized trials, with post-treatment follow-up, can provide robust substantiation of current evidence.

Tolerability and clinical efficacy of oral immunotherapy with house dust mites in a model of canine atopic dermatitis: a pilot study

Atopic dermatitis (AD) is a chronic, life-long disease. In humans, immunotherapy (IT) is the only treatment that can alter the course of AD. Oral IT is appealing owing to the ease of administration and the potential for increased compliance. The purposes of this study were to investigate the tolerability, clinical efficacy and effects on allergen-specific IgE of oral IT using a canine AD model. Thirteen atopic beagles sensitized to house dust mites (HDMs) were randomly divided into two groups. One group received daily oral doses of HDMs while the other group received vehicle only for 7 months. The investigator evaluating the dogs was blinded to the allocation of treatments. Prior to and after 2 and 7 months of IT, dogs were challenged daily with HDMs for 3 days concurrently, and clinical signs were scored using a modified Canine Atopic Dermatitis Extent and Severity Index (CADESI). Prior to and at completion of oral IT, serum was collected for measurement of allergen-specific IgE. Oral IT was well tolerated, and no adverse effects were noted. Analysis of variance showed no significant effect of time, group and group × time interaction for CADESI scores. In addition, there were no significant differences in allergen-specific IgE levels. In conclusion, it appears that oral administration of HDMs is well tolerated in these atopic beagles but that this protocol was not sufficient to induce clinical improvement. Further, longer-term studies will be necessary to explore the potential of oral IT in veterinary medicine.

Intracerebroventricular injection of leukotriene B4 attenuates antigen-induced asthmatic response via BLT1 receptor stimulating HPA-axis in sensitized rats

Background

Basic and clinical studies suggest that hypothalamic-pituitary-adrenal (HPA) axis is the neuroendocrine-immnue pathway that functionally regulates the chronic inflammatory disease including asthma. Our previous studies showed corresponding changes of cytokines and leukotriene B₄ (LTB₄) between brain and lung tissues in antigen-challenged asthmatic rats. Here, we investigated how the increased LTB₄ level in brain interacts with HPA axis in regulating antigen-induced asthmatic response in sensitized rats.

Methods

Ovalbumin-sensitized rats were challenged by inhalation of antigen. Rats received vehicle, LTB₄ or U75302 (a selective LTB₄ BLT1 receptor inhibitor) was given via intracerebroventricular injection (i.c.v) 30 min before challenge. Lung resistance (R_L) and dynamic lung compliance (C_dyn) were measured before and after antigen challenge. Inflammatory response in lung tissue was assessed 24 h after challenge. Expression of CRH mRNA and protein in hypothalamus were evaluated by RT-PCR and Western Blot, and plasma levels of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were measured using the ELISA kits.

Results

Antigen challenge decreased pulmonary function and induced airway inflammation, evoked HPA axis response in sensitized rats. Administration of LTB₄ via i.c.v markedly attenuated airway contraction and inflammation. Meanwhile, LTB₄ via i.c.v markedly increased CORT and ACTH level in plasma before antigen challenge, and followed by further increases in CORT and ACTH levels in plasma after antigen challenge in sensitized rats. Expression of CRH mRNA and protein in hypothalamus were also significantly increased by LTB₄ via i.c.v in sensitized rats after antigen challenge. These effect were completely blocked by pre-treatment with BLT1 receptor antagonist U75302 (10 ng), but not by BLT2 antagonist LY255283.

Conclusions

LTB₄ administered via i.c.v down-regulates the airway contraction response and inflammation through activation of the HPA axis via its BLT1 receptor. This study expands our concept of the regulatory role of intracranial inflammatory mediators in inflammatory diseases including asthma. The favourable effects of LTB₄ on the HPA axis may help to explain the phenomenon of self-relief after an asthmatic attack.

Mucosal immunity in mice induced by orally administered transgenic rice

Transgenic plants are efficient means of producing and delivering oral vaccines. Rice material shown previously to express the Chlamydophila psittaci (Cp. psittaci) antigen (MOMP) fused to the B subunit of Escherichia coli heat-labile enterotoxin (LTB) was fed to mice and the resulting immune response was investigated. Oral immunization of mice with the transgenic rice elicited MOMP-specific sera IgG and IgA antibodies, a strong increase of the lymphoproliferative response, and significant levels of IFN-gamma, TGF-beta and IL-2 production. Furthermore, the immunization of mice with transgenic rice elicited strong cytotoxic T lymphocyte (CTL) responses in vitro. These results demonstrated that plant-made LTB-MOMP fusion protein could induce significant humoral and cellular Th1 and Th3 immune responses. Moreover, transgenic rice immunization induced partial protection (53.3%) against a lethal challenge with the highly virulent Cp. psittaci 6BC strain in a BALB/c mouse model. These results suggest that expression of protective antigens of Cp. psittaci in transgenic rice has potential as an edible vaccine against avain chlamydiosis.