Effect of Oral Immunotherapy on Nasal Blockage in Experimental Allergic Rhinitis

Evaluating the Protective Properties of a Xyloglucan-Based Nasal Spray in a Mouse Model of Allergic Rhinitis

A breached nasal epithelial barrier plays an important role in driving allergic rhinitis (AR). Corticosteroids remain the standard of care (SoC) but come with side effects, thus alternative safe and effective treatments able to avoid inflammation and restore barrier integrity are needed. The aim of the present study is to evaluate the barrier-forming capacity of a xyloglucan-based nasal spray (XG) and compare its efficacy to several SoC treatments (corticosteroid spray, oral mast-cell stabilizer and oral antihistamine) in reducing allergic responses in addition to its effect when concomitantly administered with an antihistamine. An ovalbumin (OVA)-induced mouse AR model was used. XG shows a significant efficacy in reducing histological damage in AR mice; improves nasal rubbing and histamine-induced hyper-responsiveness. Total and OVA-specific IgE as well as pro-inflammatory cytokines are significantly reduced compared to OVA challenged-mice, with im-proved efficacy when used as an add-on treatment. However, XG reduces mucous secreting cells (PAS-positive) and mucin mRNA expression similar to the corticosteroid-treated mice. XG-spray maintains tight junction protein expression (ZO-1) and conversely decreases HDAC1 significantly; the latter being highly expressed in AR patients. Moreover, the concomitant treatment showed in all of the endpoints a similar efficacy to the corticosteroids. This innovative approach may represent a novel therapeutic strategy for nasal respiratory diseases like AR, reducing undesirable side effects and improving the quality of life in patients.

Longitudinal study of effects of oral dosage of Bifidobacterium bifidum G9-1 on Japanese cedar pollen-induced allergic nasal symptoms in guinea pigs

Previous studies using experimental animal models have reported the beneficial effects of probiotics on allergic responses; however, their long-term effects on allergic nasal symptoms in clinical settings have not yet been elucidated in detail. In the present study, a guinea pig allergic rhinitis model involving repeated inhalation challenges with a natural allergen, Japanese cedar pollen, was used to examine the longitudinal effects of Bifidobacterium bifidum G9-1 (BBG9-1) on allergic nasal symptoms. BBG9-1 was administered orally once a day. Amelioration of nasal blockage was consistently observed throughout the experimental period in the BBG9-1-treated group. Although challenge-induced sneezing was not significantly inhibited in the BBG9-1-treated group, prolonged treatment with BBG9-1 slightly reduced the frequency of sneezing. Antigen-specific IgE antibody production was also not inhibited in the BBG9-1-treated group. Increases in the numbers of eosinophils and neutrophils in nasal cavity lavage fluid collected after pollen challenge were almost completely suppressed by BBG9-1 treatment, whereas those in mast cell mediators, histamine and cysteinyl leukotrienes were not. In contrast, increases in the levels of nitric oxide metabolites were potently suppressed. Furthermore, prolonged BBG9-1 treatment markedly suppressed exogenous leukotriene D4 -induced nasal blockage. Thus, prolonged oral administration of BBG9-1 suppresses Japanese cedar pollen-induced allergic nasal symptoms. The inhibitory mechanisms responsible may involve reductions in the responsiveness of target organs, such as endothelial cells in nasal mucosal blood vessels, to chemical mediators.

Establishment and characterization of an experimental mouse model of allergic rhinitis

Allergic rhinitis (AR) is a common worldwide disease. Animal studies on AR were adopted in various investigations. However, animal studies simply aimed at establishing an animal model for AR have been seldom seen. The purpose of this study was to introduce an easy-to-establish experimental mouse model of AR. To develop a mouse model of AR, 38 Balb/c mice were randomly assigned to two groups. Mice in the study group were sensitized by intraperitoneal (IP) injection of ovalbumin (OVA) on day 1 and 6, followed by continuous inhalation (IH) of OVA solution for 1 week (day 8-14) using a newly designed inhalation box. The control group mice received sensitization of IP normal saline and IH sterilized distilled water instead of OVA. Before and after sensitization, the frequencies of nasal symptoms (sneezing, nasal rubbing) were recorded and the serum levels of total immunoglobulin E (IgE) were evaluated using ELISA. Finally, the murine nasal mucosal tissues were stained by Giemsa solution to estimate the degree of mast cell infiltration. After sensitization by IP and IH OVA, the study group showed significant phenotypic changes including increased sneezing and rubbing. Pathological and cytological findings also confirmed significant elevated serum total IgE titer and local mast cell infiltration in the study group statistically. We successfully developed a workable experimental animal model for AR that was more easily sensitized using our new-designed inhalation box, with less stress and more precisely to be observed.

Effect of Ganoderma lucidum on pollen-induced biphasic nasal blockage in a guinea pig model of allergic rhinitis

Ganoderma lucidum (GL), an oriental medical mushroom, has been used in Asia for the prevention and treatment of a variety of diseases. However, the effect of GL on allergic rhinitis has not been well defined. The current study describes the inhibitory effect of GL on the biphasic nasal blockage and nasal hyperresponsiveness induced by repeated antigen challenge in a guinea pig model of allergic rhinitis. Intranasally sensitized guinea pigs were repeatedly challenged by inhalation of Japanese cedar pollen once every week. Ganoderma lucidum was orally administered once daily for 8 weeks from the time before the first challenge. The treatment with GL dose-dependently inhibited the early and late phase nasal blockage at the fifth to ninth antigen challenges. Furthermore, nasal hyperresponsiveness to intranasally applied leukotriene D₄ on 2 days after the eighth antigen challenge was also inhibited by the treatment with GL. However, Cry j 1-specific IgE antibody production was not affected by the treatment. In conclusion, we demonstrated that the pollen-induced biphasic nasal blockage and nasal hyperresponsiveness were suppressed by the daily treatment with GL in the guinea pig model of allergic rhinitis. These results suggest that GL may be a useful therapeutic drug for treating patients with allergic rhinitis.

Lactobacillus strains stabilize intestinal microbiota in Japanese cedar pollinosis patients

A randomized double-blind, placebo-controlled trial was conducted to ascertain the intestinal microbiota-altering properties of LGG and L. gasseri TMC0356 (TMC0356) in Japanese cedar Cryptomeria japonica pollinosis patients. Fecal bacteria communities were examined before and after fermented milk administration using culture, FISH and T-RFLPmethods. Test group subjects showed the presence of LGG and TMC0356 along with a significant increase in fecal lactobacilli (P < 0.001) after giving LGG and TMC0356 fermented milk. Culture and FISH analysis revealed no significant changes in other intestinal bacterial groups. Each subject exhibited a characteristic T-RFLP profile pattern that varied quantitatively and qualitatively with JCP shedding. Profile changes were observed in 53% of placebo group subjects and in 21% of test group subject's post-administration, indicating that LGG and TMC0356 suppressed intestinal microbiota changes in JCPsis patients. The results suggest that intestinal microbiota might be more sensitive to exposure to environmental allergens than expected from the results of general culture method studies. Stabilization of intestinal microbiota by selected probiotic strains such as LGG and TMC0356 could be beneficial to homeostasis of the intestinal microbiota and useful in the management of JCPsis.

Effect of local nasal immunotherapy on nasal blockage in pollen-induced allergic rhinitis of Guinea pigs

BACKGROUND

As a non-injection route for immunotherapy, local nasal immunotherapy has been examined in allergic rhinitis patients. However, it is unclear how the immunotherapy affects sneezing, biphasic nasal blockage and nasal hyperresponsiveness. Thus, we evaluated the therapeutic effects of nasal immunotherapy on the symptoms of guinea pig allergic rhinitis. Additionally, we also evaluated whether the immunotherapy relieved pollen-induced allergic conjunctivitis.

METHODS

Sensitized animals were repeatedly challenged by pollen inhalation once every week. After the 7th challenge, the pollen extract was intranasally administered 6 times a week until the 30th challenge. Sneezing frequency was counted after each of the challenges. As an indicator of nasal blockage, changes in specific airway resistance were measured. Nasal hyperresponsiveness was assessed by measuring leukotriene D(4)-induced nasal blockage. Additionally, during the immunotherapy, we applied pollen onto the ocular surface to induce the allergic conjunctivitis symptoms.

RESULTS

At the 11th-30th challenges, the nasal immunotherapy showed inhibition or a tendency to inhibit the biphasic nasal blockage although the inhibitions were variable at respective challenges. The development of nasal hyperresponsiveness was markedly suppressed by the immunotherapy. Nevertheless, neither sneezing nor antigen-specific IgE antibody production was substantially influenced by the immunotherapy. On the other hand, the nasal immunotherapy did not affect the induction of allergic conjunctivitis symptoms.

CONCLUSIONS

Local nasal immunotherapy may be clinically useful for allergic nasal blockage associated with nasal hyperresponsiveness. The mechanisms responsible for this effectiveness might not be related to IgE production. Additionally, the effectiveness for nasal tissue was dissociated from that seen for the ocular tissue.

Effect of fermented milk prepared with two probiotic strains on Japanese cedar pollinosis in a double-blind placebo-controlled clinical study

There has been much interest in the potential of using probiotic bacteria for treating allergic diseases. A double-blind, placebo-controlled study was conducted to examine the effectiveness of Lactobacillus GG (LGG) and L. gasseri TMC0356 (TMC0356) in alleviating Japanese cedar pollinosis (JCP), a seasonal allergic rhinitis caused by Japanese cedar pollen. Fermented milk prepared with the tested bacteria or placebo yoghurt was administered to 40 subjects with a clinical history of JCP for 10 weeks. Subjective symptoms, self-care measures and blood samples were compared between the two groups. Peripheral blood mononuclear cells (PBMCs) were collected from seven patients with JCP and in vitro cytokine production by the isolated PBMCs was analysed in the presence of heat-killed lactic acid bacteria. Consumption of the fermented milk significantly decreased the mean symptom score for nasal blockage after 9 weeks (P<0.05) and mean symptom-medication scores after 9 and 10 weeks when compared with the placebo group (P<0.01 and P<0.05 respectively). The tested strains of lactic acid bacteria affected cytokine production by isolated PBMCs in vitro in a strain-dependent manner. LGG significantly inhibited IL-4 and IL-5 production by PBMCs stimulated by both Cry j 1 and PHA. TMC0356 only suppressed IL-5 production stimulated by PHA. The fermented milk prepared with LGG and TMC0356 might be beneficial in JCP because of its effect on nasal blockage. The effects of LGG and TMC0356 might arise at least partly from their specific down-regulation of the human Th2 immune response.

Effects of multiple dexamethasone treatments on aggravation of allergic conjunctivitis associated with mast cell hyperplasia

In a Japanese cedar pollen-induced allergic conjunctivitis model in guinea pigs, symptoms were aggravated by repeated pollen challenges. In addition, the number of mast cells in the conjunctiva was increased by multiple challenges. The amount of a mast cell mediator, histamine in ophthalmic lavage fluid was also increased by multiple challenges. In the present study, we evaluated the effects of multiple dexamethasone treatments to assess the relationship between the aggravation of symptoms and mast cell hyperplasia. Sensitized guinea pigs were challenged by dropping a pollen suspension onto their eye surface once a week until the 15th challenge. Dexamethasone (10 mg/kg, p.o.) was administered once 3 h before the 15th challenge or 3 h before every 1st--15th challenge. Mast cells in the conjunctival tissue were detected by toluidine blue staining. Histamine was fluorometrically assayed by high-performance liquid chromatography. Serum Cry j 1-specific IgE titer was measured by an enzyme-linked immunosorbent assay. The results indicated that a single treatment with dexamethasone did not affect the 15th challenge-induced symptoms; however, multiple treatments with the corticosteroid suppressed not only conjunctivitis symptoms after every challenge but also the mast cell hyperplasia and the increase in histamine in the lavage fluid. Conversely, the increase in the IgE titer in the serum was not affected by multiple treatments with dexamethasone. In conclusion, increased numbers of mast cells in the conjunctival tissue may be associated with the aggravation of allergic conjunctivitis symptoms.

Polycyclic aromatic hydrocarbons aggravate antigen-induced nasal blockage in experimental allergic rhinitis

It has been hypothesized that air pollution has played a role in the increase in allergy prevalence. However, it remains unclear what exact roles are played by polycyclic aromatic hydrocarbons (PAHs), which are encountered in the environment in the form of air pollution, in allergic rhinitis. Thus, we examined whether benzo(a)pyrene (BaP) and 1-nitropyrene (1-NP), representative PAHs, aggravate allergic rhinitis symptoms, using a guinea-pig model. Sensitized animals were repeatedly challenged by inhalation of Japanese cedar pollen once a week. BaP or 1-NP was daily and intranasally administered for 2 weeks (short-term treatment) or for 22 weeks from the time before the sensitization period (long-term treatment). The short-term treatment affected neither nasal blockage nor sneezing induced by antigen. In contrast, the long-term treatment aggravated the antigen-induced nasal blockage that was induced 7 weeks after the start of the treatment with BaP or 1-NP. This aggravation continued during the intranasal treatment with PAH. However, neither sneezing nor Cry j 1-specific IgE antibody production was affected even by the long-term treatment. In conclusion, the long-term treatment with BaP and 1-NP can aggravate allergic rhinitis. The mechanisms underlying this aggravation are not associated with production of Cry j 1-specific IgE.

Development and Evaluation of a Direct Sandwich Enzyme-Linked Immunosorbent Assay for the Quantification of Guinea-Pig Immunoglobulin E

The purpose of this study was to develop and evaluate a direct sandwich enzyme-linked immunosorbent assay (ELISA) for the immunoglobulin E (IgE) in serum and plasma from guinea pig using mouse monoclonal antibodies specific for guinea-pig IgE. Mouse monoclonal antibodies were raised against purified IgE protein. The ELISA was performed using a combination of two anti-IgE monoclonal antibodies. One antibody was labeled with horseradish peroxidase (HRP), and the other was coated on polystyrene wells. Purified guinea-pig IgE was used as the standard material. The validity of the ELISA was confirmed by precision, dilution, recovery, and interference tests. The range of detection was 3.1-800 ng of IgE mass per mL of serum and plasma. The intra- and inter-assay coefficients of variation were 4.6% and 5.7%, respectively, or less. The recovery test showed variation only between 92.1% and 111.8%, and the anticoagulants showed noninterference with the IgE assay. The mean serum IgE mass concentration in OVA-sensitized guinea pigs was 29438 ng/mL, and it was 48.6 ng/mL in normal guinea pigs. The present ELISA is useful and practical for specific measurement of the guinea-pig IgE, and it is surmised that it would be suitable for use in allergological and pharmacological research.