Increased Bronchoalveolar Lavage Fluid Neutrophils Research Articles

The Role of Thoracic Ultrasonography and Airway Endoscopy in the Diagnosis of Equine Asthma and Exercise-Induced Pulmonary Hemorrhage.

Mild-moderate (MEA), severe (SEA) equine asthma and exercise-induced pulmonary hemorrhage (EIPH) are common respiratory disorders in horses. The present retrospective study aims to evaluate the role of ultrasonography and endoscopy in the diagnosis of these conditions. Three hundred and three horses were included and divided into SEA, MEA and MEA + EIPH groups, on the basis of history, clinical examination and bronchoalveolar lavage fluid (BALf) cytology; scores were assigned to lung ultrasonography, pharyngeal lymphoid hyperplasia (PLH), tracheal mucus (TM) and tracheal bifurcation edema (TB). These scores were compared between groups, and their associations with age, BALf cytology, tracheal wash microbiology and between endoscopic and ultrasonographic scores were statistically analyzed. Ultrasonographic scores were higher in the SEA and MEA + EIPH groups and associated with increased BALf neutrophils and hemosiderophages. The PLH score was higher in younger horses affected by MEA and EIPH and associated with increased eosinophils and hemosiderophages. TM and TB scores were greater in older horses affected by SEA, associated with increased neutrophils and inversely correlated with hemosiderophages. Moreover, TM grade was negatively correlated with mast cells. Thoracic ultrasonography and airway endoscopy can provide useful information about the inflammatory status of upper and lower airways in the horse.

ATP-Binding Cassette Transporter 1 Attenuates Ovalbumin-Induced Neutrophilic Airway Inflammation

Apolipoprotein A-I (apoA-I) is an important component of high-density lipoprotein particles that mediates reverse cholesterol transport out of cells by interacting with the ATP-binding cassette transporter 1 (ABCA1). apoA-I has also been shown to attenuate neutrophilic airway inflammation in experimental ovalbumin (OVA)-induced asthma by reducing the expression of granulocyte colony-stimulating factor (G-CSF). Here, we hypothesized that overexpression of the ABCA1 transporter might similarly attenuate OVA-induced neutrophilic airway inflammation. Tie2-human ABCA1 (hABCA1) mice expressing human ABCA1 under the control of the Tie2 promoter, which is primarily expressed by vascular endothelial cells, but can also be expressed by macrophages, received daily intranasal OVA challenges, 5 d/wk for 5 weeks. OVA-challenged Tie2-hABCA1 mice had significant reductions in total bronchoalveolar lavage fluid (BALF) cells that reflected a decrease in neutrophils, as well as reductions in peribronchial inflammation, OVA-specific IgE levels, and airway epithelial thickness. The reduced airway neutrophilia in OVA-challenged Tie2-hABCA1 mice was associated with significant decreases in G-CSF protein levels in pulmonary vascular endothelial cells, alveolar macrophages, and BALF. Intranasal administration of recombinant murine G-CSF to OVA-challenged Tie2-hABCA1 mice for 5 days increased BALF neutrophils to a level comparable to that of OVA-challenged wild-type mice. We conclude that ABCA1 suppresses OVA-induced airway neutrophilia by reducing G-CSF production by vascular endothelial cells and alveolar macrophages. These findings suggest that ABCA1 expressed by vascular endothelial cells and alveolar macrophages may play important roles in attenuating the severity of neutrophilic airway inflammation in asthma.

Disparate features of allergic airway disease between young and old mice

The prevalence of asthma in the elderly (>;65) is increasing and associated with higher mortality than in children or young adults. Despite this increase, the effects of age on the development, character and severity of allergic asthma have been understudied. To elucidate the influence of age on allergic airway disease, we compared pulmonary responses of young (10‐week) and old (14‐month) BALB/c mice that were intranasally sensitized and challenged with house dust mite extract (HDM). After challenge, bronchoalveolar lavage fluid (BALF) was collected for cell and cytokine analysis and lung tissue was processed for gene expression analysis and histopathology. Both young and old mice developed HDM‐induced allergic airway disease. This was manifested by the presence of BALF eosinophlis and Th2 cytokines (IL5, IL13), as well as elevated gene expression of eotaxin, chitinase 3‐like 4 and airway mucus regulating genes Gob5 and Muc5AC. Compared to young mice, old mice had a significantly greater pulmonary allergic response (e.g., 10 × more eosinophils and IL13). In addition, only old mice showed a Th17 immune response to HDM characterized by increased BALF neutrophils and IL17, IL6 and KC cytokines. These results suggest that the severity and character of allergic airway disease is age dependent and the elderly may be prone to develop more severe allergic asthma with a mixed Th2/Th17 immune response. USEPA RD83479701

Elevated amount of Toll-like receptor 4 mRNA in bronchial epithelial cells is associated with airway inflammation in horses with recurrent airway obstruction

Recurrent airway obstruction (RAO) is characterized by neutrophilic airway inflammation and obstruction, and stabling of susceptible horses triggers acute disease exacerbations. Stable dust is rich in endotoxin, which is recognized by Toll-like receptor (TLR) 4. In human bronchial epithelium, TLR4 stimulation leads to elevation of interleukin (IL)-8 mRNA expression. The zinc finger protein A20 negatively regulates this pathway. We hypothesized that TLR4 and IL-8 mRNA and neutrophil numbers are elevated and that A20 mRNA is not increased in RAOs during stabling compared with controls and with RAOs on pasture. We measured the maximal change in pleural pressure (DeltaPpl(max)), determined inflammatory cell counts in bronchoalveolar lavage fluid (BAL), and quantified TLR4, IL-8, and A20 mRNA in bronchial epithelium by quantitative RT-PCR. We studied six horse pairs, each pair consisting of one RAO and one control horse. Each pair was studied when the RAO-affected horse had airway obstruction induced by stabling and after 7, 14, and 28 days on pasture. Stabling increased BAL neutrophils, DeltaPpl(max), and TLR4 (4.14-fold change) significantly in RAOs compared with controls and with RAOs on pasture. TLR4 correlated with IL-8 (R2 = 0.75). Whereas stabling increased IL-8 in all horses, A20 was unaffected. IL-8 was positively correlated with BAL neutrophils (R2 = 0.43) and negatively with A20 (R2 = 0.44) only in RAO-affected horses. Elevated TLR4 expression and lack of A20 upregulation in bronchial epithelial cells from RAO-affected horses may contribute to elevated IL-8 production, leading to exaggerated neutrophilic airway inflammation in response to inhalation of stable dust.

Repeated hyperventilation causes peripheral airways inflammation, hyperreactivity, and impaired bronchodilation in dogs.

Winter athletes have an increased incidence of asthma, suggesting that repetitive hyperventilation with cold air may predispose individuals to airways disease. We used a canine model of exercise-induced hyperpnea to examine the effects of repeated hyperventilation with cool, dry air (i.e., dry air challenge [DAC]) on peripheral airway resistance (Rp), reactivity, and inflammation. Specific bronchi were exposed to a single DAC on five consecutive days. Rp and Delta Rp to aerosolized histamine, intravenous histamine, or hypocapnia were measured daily. Bronchoalveolar lavage fluid (BALF) was obtained on the fifth day. Rp increased from 0.70 +/- 0.08 to 1.13 +/- 0.22 cm H(2)O/ml/s (n = 25) 24 h after the first DAC, rose to 1.49 +/- 0.24 cm H(2)O/ml/s by Day 3, and remained elevated throughout the remainder of the protocol. Repeated DAC increased reactivity to hypocapnia and intravenous histamine. Intravenous salbutamol failed to reduce Rp as effectively in challenged airways (111% of Day 1 baseline) as in naive airways (54% of baseline). Repeated DAC caused increased BALF neutrophils, eosinophils, and sulfidopeptide leukotrienes. We conclude that repeated DAC causes peripheral airways inflammation, obstruction, hyperreactivity, and impaired beta-agonist-induced relaxation. This suggests that other mechanisms in addition to increased smooth muscle tone may contribute to the development of repetitive hyperventilation-induced bronchial obstruction and hyperreactivity.

Antioxidant transport modulates peripheral airway reactivity and inflammation during ozone exposure.

We examined the effects of ozone (O(3)) and endogenous antioxidant transport on canine peripheral airway function, central airway function, epithelial integrity, and inflammation. Dogs were either untreated or pretreated with probenecid (an anion-transport inhibitor) and exposed for 6 h to 0.2 parts/million O(3). Peripheral airway resistance (Rpa) and reactivity (DeltaRpa) were monitored in three sublobar locations before and after exposure to either air or O(3). Pulmonary resistance and transepithelial potential difference in trachea and bronchus were also recorded. Bronchoalveolar lavage fluid (BALF) was collected before, during, and after exposure. O(3) increased Rpa and DeltaRpa only in probenecid-treated dogs and in a location-dependent fashion. Pulmonary resistance and potential difference in bronchus increased after O(3) exposure regardless of treatment. O(3) markedly increased BALF neutrophils only in untreated dogs. With the exception of hexanal, O(3) did not alter any BALF constituent examined. Probenecid reduced BALF ascorbate, BALF protein, and plasma urate. We conclude that 1) a 6-h exposure to 0.2 parts/million O(3) represents a subthreshold stimulus in relation to its effects on peripheral airway function in dogs, 2) antioxidant transport contributes to the maintenance of normal airway tone and reactivity under conditions of oxidant stress, 3) O(3)-induced changes in Rpa and DeltaRpa are dependent on location, and 4) peripheral airway hyperreactivity and inflammation reflect independent responses to O(3) exposure. Finally, although anion transport mitigates the effect of O(3) on peripheral airway function, it contributes to the development of airway inflammation and may represent a possible target for anti-inflammatory prevention or therapy.

Alveolar macrophage cytokine and growth factor production in a rat model of crocidolite-induced pulmonary inflammation and fibrosis.

The present study was undertaken to further define the role of alveolar macrophages (AM) in the pulmonary response to crocidolite fibers. Briefly, groups of 4 male F344 rats were intratracheally instilled with saline or saline suspensions of crocidolite at 2 or 20 mg/kg body weight. Animals were sacrificed 3, 7, 14, and 28 d after exposure and the lung response was characterized by analysis of bronchoalveolar lavage fluid (BALF) for markers of lung injury and inflammation. AM obtained in BALF were cultured and their production of the pro-inflammatory cytokines, tumor necrosis factor alpha (TNF alpha), and interleukin-1 (IL-1) were characterized along with fibronectin, a protein known to stimulate fibroblast migration and proliferation. Lung hydroxyproline content was determined 28 d after exposure and lung histopathology was characterized on d 28 and 90 after exposure. Crocidolite instillation resulted in transient dose-related pulmonary inflammation as evidenced by increased numbers of BALF neutrophils at the low dose and neutrophils, macrophages, and lymphocytes at the high dose. Cytotoxicity and increased permeability were demonstrated by increased levels of BALF lactate dehydrogenase (LDH) and total protein, respectively. AM TNF alpha and IL-1 production were increased only at the high crocidolite dose. This cytokine response was greatest at d 3 and decreased thereafter. AM TNF alpha and IL-1 release were positively correlated with the increased BALF neutrophils. In contrast to TNF alpha and IL-1, AM fibronectin release was increased at both the low and high doses, with the magnitude of response increasing over time. Consistent with previous acute asbestos inhalation studies, histopathology revealed inflammation localized at the level of the terminal bronchioles and alveolar ducts. Fibrosis was demonstrated at both doses by increased trichrome staining of lung tissue sections. Only the high dose resulted in a detectable increase in lung hydroxyproline. Given the bioactivities of TNF alpha, IL-1, and fibronectin, their increased production after crocidolite exposure indicates they contribute to the pulmonary inflammation and fibrosis occurring with this mineral fiber. In addition, the correlation of increased AM TNF alpha and IL-1 production with increased BALF neutrophils supports a role for these cytokines in crocidolite-induced inflammatory cell recruitment. Lastly, association of a persistent increase in AM fibronectin production with an eventual increase in lung collagen deposition extends the growing database indicating this response is a predictive marker of pulmonary fibrosis.

Pulmonary response to inhaled silica or titanium dioxide

The pulmonary response to mineral dust inhalation was investigated by characterizing markers of lung injury and inflammation, macrophage activation, dust clearance, and histopathology. Rats were exposed (6 hr/day × 5 days) to air or 50 mg/m 3 crystalline silica (SiO 2) or titanium dioxide (TiO 2). At 7, 14, 28, and 63 days after exposure, bronchoalveolar lavage fluid (BALF) was analyzed for lactate dehydrogenase (LDH), total protein, and N-acetyglucosaminidase, as well as cell number, type, and viability. Alveolar macrophages (AM) obtained in BALF were cultured with or without LPS and release of interleukin-1 (IL-1) and fibronectin was determined. Histopathology was conducted at 28 and 63 days. The exposure protocol resulted in 18–19 mg of mineral dust being deposited in the pulmonary region. Clearance of SiO 2 was significantly less than TiO 2. SiO 2 increased BALF neutrophils (Days 14, 28, and 63), total protein (Days 28 and 63), and LDH and lymphocytes (Day 63). SiO 2 increased AM-derived fibronectin release (Day 63) and LPS-induced IL-1 release (all time points), but not spontaneous release of IL-1. TiO 2 did not change BALF biochemical or cellular parameters or AM secretory activity. Histopathology revealed minimal interstitial inflammation with SiO 2 and no significant response in control or TiO 2 rats. These results demonstrate the pulmonary response to inhaled SiO 2 can be differentiated from the relatively innocuous TiO 2 by changes in BALF markers of injury and inflammation further supporting the use of BALF analysis to make relative assessments of pulmonary toxicity. The stimulation of macrophage fibronectin release by the fibrogenic dust SiO 2 and not TiO 2 is consistent with a role for this glycoprotein in lung injury and repair. Last, the early and persistent effect of SiO 2 on LPS-induced AM IL-1 release indicates this response may represent a sensitive early marker of dust-induced changes in the AM population.