Effects of residual oil fly ash (ROFA) in mice with chronic allergic pulmonary inflammation

Exposure to particulate matter (PM) air pollution is associated with increased asthma morbidity. Residual oil flash ash (ROFA) is rich in water-soluble transition metals, which are involved in the pathological effects of PM. The objective of this study was to investigate the effects of intranasal administration of ROFA on pulmonary inflammation, pulmonary responsiveness, and excess mucus production in a mouse model of chronic pulmonary allergic inflammation. BALB/c mice received intraperitoneal injections of ovalbumin (OVA) solution (days 1 and 14). OVA challenges were performed on days 22, 24, 26, and 28. After the challenge, mice were intranasally instilled with ROFA. After forty-eight hours, pulmonary responsiveness was performed. Mice were sacrificed, and lungs were removed for morphometric analysis. OVA-exposed mice presented eosinophilia in the bronchovascular space (p < .001), increased pulmonary responsiveness (p < .001), and epithelial remodeling (p = .003). ROFA instillation increased pulmonary responsiveness (p = .004) and decreased the area of ciliated cells in the airway epithelium (p = .006). The combined ROFA instillation and OVA exposure induced a further increase in values of pulmonary responsiveness (p = .043) and a decrease in the number of ciliated cells in the airway epithelium (p = .017). PM exposure results in pulmonary effects that are more intense in mice with chronic allergic pulmonary inflammation.     

Stem cell factor-induced airway hyperreactivity in allergic and normal mice

The induction of airway hyperreactivity during allergic responses involves multiple ill-defined mechanisms. Recently a role for stem cell factor (SCF) in the development of allergic eosinophilic airway inflammation has been identified. In the present study we demonstrate that SCF has a role in both the inflammatory response and airway hyperreactivity. Neutralization of SCF or examination of SCF-mutant mice, which were deficient in SCF and pulmonary mast cells, demonstrated significant alterations in the allergen-induced airway hyperreactive responses. The reduced hyperreactivity response was accompanied by a significant reduction in eosinophil accumulation. To examine the direct role of SCF on airway hyperreactivity, we administered SCF into the airways of normal mice via intratracheal injections and demonstrated a dose dependent increase in airway hyperreactivity at 4 hours that was maintained at 24 hours after administration. Instillation of SCF into SCF-deficient (mast cell deficient) mice demonstrated significantly lower increases in airway hyperreactivity compared with the littermate controls with normal mast cell numbers. These studies demonstrate that locally expressed SCF can induce changes in airway physiology via mast cell activation, verifying the role of SCF in allergic airway inflammation and hyperreactivity.     

Salbutamol improves markers of epithelial function in mice with chronic allergic pulmonary inflammation

We investigated the effects of salbutamol on the markers of epithelial function in a murine model of chronic allergic pulmonary inflammation by recording the ciliary beat frequency (CBF) and the transepithelial potential difference (PD) in vivo. Mice were sensitized and received four challenges of ovalbumin (OVA group) or 0.9% saline (control group). Forty-eight hours after the 4th inhalation, we observed eosinophilia in the bronchoalveolar lavage and epithelium remodeling with stored acid mucus in the OVA group (P < 0.001). No difference in the baseline CBF was noticed between the groups; however, the OVA group had a significantly lower baseline PD (P = 0.013). Salbutamol increased the CBF in all groups studied, and the dose response curve to salbutamol increased the PD in the OVA group from 10(-4)M to 10(-2)M. We suggest that salbutamol affects the CBF and the depth of the periciliary layer, which, in great part, determines the ability of the cilia to propel the mucus layer. This effect may have a positive impact on airway mucociliary transport in asthma and may have clinical implications.     

An in vivo model of allergic inflammation: pulmonary human cell infiltrate in allergen-challenged allergic Hu-SCID mice

CB.17 severe combined immunodeficient (SCID) mice were used to establish a model of allergic pulmonary inflammation. SCID mice were intraperitoneally reconstituted with 10⁷ peripheral blood mononuclear cells (PBMC) from patients sensitive to Dermatophagoides pteronyssinus (Dpt) and 2 weeks later were exposed to Dpt aerosols. After Dpt nebulization, SCID mice engrafted with PBMC from Dpt-sensitive patients developed a specific human IgE response as well as an intense pulmonary infiltrate of human cells. In contrast, SCID mice reconstituted with PBMC from patients allergic to grass pollen or from nonallergic donors failed to produce IgE or to exhibit a similar inflammatory response. The level of the IgE production was dependent on the IgE level of the allergic donor. In the lungs of the same allergic SCID mice, 2 months after Dpt inhalation, the cell infiltrate contained CD45⁺, CD45RO⁺, CD20⁺ and HLA-DR⁺ human cells. They were located in perivascular and peribronchial areas and disseminated in the mouse lung parenchyma. Moreover, mRNA IL-5⁺ cells and eosinophils were found in peribronchial infiltrates. The observations indicate that humanized allergic SCID mice may develop, after nebulization with the relevant allergen, immune reactions similar to those observed in man and suggest that SCID mice may represent a useful model to analyze the regulatory mechanisms of IgE-associated allergic diseases.     

Bronchial hyperreactivity and spirometric impairment in patients with perennial allergic rhinitis

BACKGROUND: Allergic disorders are characterized by a systemic involvement of the immune response. There is a clear link between allergic rhinitis and asthma. Bronchial hyperreactivity (BHR) may be present in rhinitics. Smaller airways may also be impaired in mild asthma. This study aimed at evaluating a group of subjects suffering from perennial allergic rhinitis alone to investigate the presence of BHR and spirometric impairment. METHODS: One hundred rhinitics sensitized only to perennial allergens were evaluated. Spirometry and methacholine bronchial challenge were performed. RESULTS: Five rhinitics showed reduced values of forced expiratory volume/1 s (FEV(1)) without symptoms of asthma. Forty-eight rhinitics had reduced forced expiratory flow at 25 and 75% of pulmonary volume (FEF(25-75)) values. Seventy-two patients showed a positive methacholine challenge. In this group, reduced values of FVC (p < 0.05), FEV(1) (p < 0.05), and FEF(25-75) (p < 0.01) were demonstrated in comparison with BHR-negative rhinitics. There was a relationship between the degree of BHR and FEV(1) values (p < 0.05) and FEF(25-75) values (p < 0.01). CONCLUSIONS: This study evidences that an impairment of spirometric parameters may be observed in patients with perennial allergic rhinitis alone. A high percentage of these patients have BHR. Thus, new management strategies should be employed in rhinitics.     

Nasal cytology in allergic processes and other syndromes caused by hyperreactivity

The spontaneous nasal secretions from about 128 patients with the symptomatic triad of rhinorrhea, sneezing, and nasal obstruction were studied. The cytological examination consisted of a morphological evaluation and a semiquantitative evaluation. Noncellular and nonliving presences in the smears have been considered, including mucus, Charcot-Layden crystals, and pollen grains, as well as fungi and bacilli. We found a net increase in eosinophils, goblet cells, and cellular debris in secretions of atopic patients. Pollen grains and vegetative fragments were present in the nasal smears of pollinosis. The presence of fungi was observed in five cases of allergic rhinopathy. The exfoliative cytology represents a valuable means for the differential diagnosis of rhinitis. In particular, the presence of noncellular elements has value regarding rhinocytology.     

Post-weaning crowding induces corticoadrenal hyperreactivity in male mice

The effect of various population densities on corticoadrenal function was studied in prepuberal male mice. High population densities decreased body weight gain. Neither adrenal weight nor basal serum corticosterone were modified by crowding. However, corticoadrenal response to some acute stresses such as noise and forced swimming was higher in crowded mice. As corticoadrenal response to adrenocorticotropin remained unaffected, it appears that crowding induced pituitary-adrenal hyperreactivity. Neither the defecation rate nor exploratory activity were altered by crowding, suggesting a dissociation between pituitary-adrenal responsiveness and behavioral measures presumably related to emotional arousal. These discrepancies may possibly be due to the higher sensitivity of corticoadrenal function to environmental changes. Our results suggest that crowding would be suitable as a model for chronic continuous stress.     

Sulphur dioxide-induced airway hyperreactivity and pulmonary inflammation in dogs

Anaesthetised Beagle dogs were exposed to sulphur-dioxide (SO₂) for 2 h and the pulmonary effects studied up to 24 h using bronchoalveolar lavage (BAL) and lung mechanics measurements. SO₂-induced hyperreactivity to histamine was associated with epithelial cell shedding, an increase in airway permeability to plasma proteins and an increase in BAL PGE₂ content. Leukotrienes were not recovered in BAL. Ibuprofen reduced hyperreactivity at 24 h post SO₂ but not immediately after SO₂ and had no effect on BAL cells at anytime. These results suggest that 2 phases of hyperreactivity exist—an immediate effect which may involve epithelial cell loss and a later phase which may be inflammatory.     

Modification of bronchial hyperreactivity during pollen season in children allergic to grass

Ten children, sensitive to grass pollens with seasonal rhinitis and mild asthma, underwent bronchial challenge with carbachol in the pre-seasonal, seasonal, and post-seasonal period. According to pollen count, we observed significant differences between pre-seasonal, seasonal, and post-seasonal values. Also basal FEV1 values varied in the same fashion. Seven of the ten children also participated in a previous similar study in 1984, at which time they did not demonstrate significant variations to bronchial challenge. We wish to emphasize the importance of pollen concentration in the atmosphere as well as the existence of a threshold value of grass pollen necessary for a significant modification in bronchial reactivity to occur.     

HLA-DRB1 alleles control allergic bronchopulmonary aspergillosis-like pulmonary responses in humanized transgenic mice

BACKGROUND: Allergic bronchopulmonary aspergillosis (ABPA) is a lung hypersensitivity disease mediated in part by CD4(+) T(H)2 cells. There is a significant association between ABPA and the HLA-DR2 genotypes DRB1(*)1501 and DRB1(*)1503, whereas resistance might be associated with HLA-DRB1(*)1502. OBJECTIVE: We sought to elucidate the role of HLA-DR alleles in allergic inflammation in lungs. METHODS: HLA-DR humanized transgenic mice expressing either the susceptible or resistant alleles were analyzed for the nature and extent of pulmonary inflammation after exposure to Aspergillus species antigens. RESULTS: Exposed DRB1(*)1501 and DRB1(*)1503 transgenic mice displayed infiltrates made up prominently of eosinophils, which is consistent with the inflammation found in ABPA. The resistant DRB1(*)1502 mice, on the other hand, displayed minimal to moderate inflammation, consisting mainly of T-cell infiltrates. Significantly more mucin was produced in the DRB1(*)1503 and DRB1(*)1501 mice, and their ability to limit the number of Aspergillus species conidia within the lung parenchyma was impaired. Despite their differences, both the DRB1(*)1503 and DRB1(*)1502 strains mounted comparable T cell-proliferative responses to Aspergillus species antigens. CONCLUSION: The HLA-DR2 alleles DRB1(*)1501 and DRB1(*)1503 play a major role in the development of allergic pulmonary inflammation. In contrast, the HLA-DR2 allele DRB1(*)1502 mediates a nonallergic T(H)1-like response to the organism, possibly explaining an ABPA resistance factor. These results are in support of our published human studies in patients with cystic fibrosis and asthma. CLINICAL IMPLICATIONS: HLA-DR typing in patients with cystic fibrosis and asthma will aid in the identification of individuals at risk for ABPA.     

Immunotherapy in children with allergic asthma: effect on bronchial hyperreactivity and pharmacotherapy

BACKGROUND: Immunotherapy has been shown to reduce allergen sensitivity to allergens such as cat and dust mite. The aim of this study was to investigate the effect of cat or dust mite immunotherapy on bronchial hyperreactivity and the need for inhaled corticosteroids in children with asthma, cat or dust mite allergy, and hay fever. SUBJECTS: Twenty-nine children, 7 to 16 years old, completed the 3-year study. They were randomly allocated to receive cat/dust mite or placebo and birch/timothy immunotherapy. METHODS: Before immunotherapy was begun and then once each year, bronchial histamine challenges were performed. Bronchial allergen challenge with the perennial allergen was done before and after the 3-year study. Pharmacotherapy was given according to a standardized protocol. RESULTS: PC20 allergen increased significantly in both the active immunotherapy group (P <.001) and in the placebo-pollen group (P <.05). PC20 histamine increased continuously in the active immunotherapy group (P <.05 and P =.002 after 1 and 3 years, respectively) and had also increased after 3 years in the placebo-pollen group (P <.05). The difference between the 2 groups was significant for PC20 allergen (P =.001) but not for PC20 histamine. There was no significant change in the dose of inhaled budesonide needed for symptom control in either of the groups. CONCLUSION: Pollen immunotherapy combined with inhaled corticosteroids results in improvement of both cat/dust mite bronchial sensitivity and hyperresponsiveness to histamine. The combination of cat or dust mite, pollen immunotherapy, and inhaled budesonide enhances this improvement. Cat immunotherapy also induces cat allergen tolerance.     

Induction of hyperreactivity to endotoxin in mice by Coxiella burnetii

Intraperitoneal inoculation of mice with live or killed Coxiella burnetii phase I or phase II cells induced a marked hyperreactivity to the lethal effect of bacterial endotoxin and was accompanied by a marked hepatosplenomegaly. The degree and duration of hyperreactivity depended on the dose of C. burnetii administered and were higher with phase I than with phase II cells. Sensitization to the lethal effects of endotoxin and induction of splenomegaly by phase I C. burnetii cells also proceeded in the endotoxin-resistant C3H/HeJ strain of mice. Preincubation of C. burnetii cells with the corresponding immune serum significantly diminished the ability of phase I but not phase II cells to induce hyperreactivity to endotoxin.     

Lipid A-induced tolerance and hyperreactivity to hypothermia in mice.

Mice responded to lipopolysaccharide (LPS) with a dose-dependent, monophasic hypothermia reaching a maximum at 2 h postinjection. Degraded polysaccharide was not active; free lipid A, however, induced a similar pattern of hypothermia, indicating that the hypothermic principle of LPS was embedded within the lipid A component. The hypothermic response of mice to LPS was modified by prior exposure of the host to LPS. This altered reactivity was manifested by refractory periods (early and late tolerance), in which animals no longer responded with hypothermia, or a hyperreactive phase (hypersensitivity), in which hypothermic responses were greatly augmented upon LPS challenge. Thus, tolerance observed 24 h after a single injection of LPS (early tolerance) was followed, on further LPS challenge, by an enhanced hypothermic responses reaching a maximum on day 4. Further daily exposure of the animals to LPS eliminated hyperreactivity and led to the establishment of a late tolerance maximally expressed on day 8. Hyperreactivity could also be evoked on day 4 after a single injection of LPS. Mice pretreated with Salmonella S- and R-form LPS or free lipid A (Salmonella) demonstrated tolerance and hyperreactivity to both homologous and heterologous challenge. In addition, complete cross-tolerance was observed with S-form LPS derived from Shigella. It was concluded that the differential effects of LPS on host responses (tolerance and hyperreactivity) were due to lipid A.     

Luteolin alleviates bronchoconstriction and airway hyperreactivity in ovalbumin sensitized mice

OBJECTIVE AND DESIGN: Asthma is an inflammatory disease of the airways and the current focus in managing asthma is the control of inflammation. In this study, we attempted to investigate the anti-asthmatic potential of a plant derived natural compound, luteolin. MATERIAL: We used a murine model of airway hyperreactivity, which mimicked some of the characteristic features of asthma. Male BALB/c mice (8-9 weeks) were used for this study. TREATMENT: Mice (n = 6) were sensitized by intraperitoneal (i. p.) injection of 10 mg of ovalbumin (OVA) on days 0, 7 and 14 followed by aerosol inhalation (5% OVA) treatments daily beginning from day 19 to day 23. To study its preventive effect, luteolin (0.1, 1.0, and 10 mg/kg body weight; daily) was administered orally during the entire period (0 to 23 day) of sensitization. To study its curative effect, mice were first sensitized and then luteolin (1.0 mg/kg body weight daily) was given orally from day 26 to 32. The airway hyperreactivity, immunoglobulin E (IgE) in the sera, and cytokines (IFN-gamma, IL-4 and IL-5) in the bronchoalveolar lavage fluid (BALF) were measured. RESULTS: Both during sensitization and after sensitization, luteolin, at a dose of 0.1 mg/kg body weight, significantly modulated OVA-induced airway bronchoconstriction and bronchial hyperreactivity (p < 0.05). Luteolin also reduced OVA-specific IgE levels in the sera, increased interferon gamma (IFN-gamma) levels and decreased the interleukin-4 (IL-4) and interleukin-5 (IL-5) levels in the BALF. CONCLUSION: Our study showed that luteolin treatment during and after sensitization significantly attenuated the asthmatic features in experimental mice. Therefore, luteolin could be used either as a lead molecule to identify an effective antiasthma therapy or as a means to identify novel anti-asthma targets.