Bronchial Preparations Research Articles

Влияние кромогликата натрия и интрамуральных ганглиев на экспрессию гена TNFR1 в бронхах крыс с овальбумин-индуцированной бронхиальной астмой

The purpose of this article was to study TNFR1 gene expression in the bronchi of rats with ovalbumininduced bronchial asthma, taking into account intramural metasympathetic ganglia and the stabilization of mast cell membranes with sodium cromoglycate. In this paper, gene expression refers to the accumulation of mRNA in bronchial tissues. Expression of the TNFR1 gene and receptor plays an important role in the development of allergic asthma. For this reason, the TNFR1 gene was chosen for the analysis. Materials and methods. Bronchial samples from Wistar rats were studied using real-time polymerase chain reaction. For experiments, bronchi with ganglia (in the bifurcation area) and bronchi without ganglia (straight sections) were taken. The material was collected from 7 groups of rats: with ovalbumin-induced bronchial asthma (6 groups) and control animals (1 group). Mast cell stabilizer sodium cromoglycate was used to treat 3 groups of rats with simulated asthma. Results. It was found that the expression of mRNA encoding TNFR1 increases in rats developing bronchial asthma. In bronchial samples with ganglia, TNFR1 gene expression was higher than in bronchial preparations without ganglia. Under the influence of sodium cromoglycate, TNFR1 gene expression decreased. Based on the results obtained, it was suggested that mast cells and neurons of the intramural ganglion have a rather pronounced effect on TNFR1 gene expression.

Bronchodilation induced by PGE2 is impaired in Group III pulmonary hypertension

In patients with pulmonary hypertension (PH) associated with lung disease and/or hypoxia (Group III), decreased pulmonary vascular tone and tissue hypoxia is therapeutically beneficial. PGE2 and PGI2 induce potent relaxation of human bronchi from non-PH (control) patients via EP4 and IP receptors, respectively. However, the effects of PGE2 /PGI2 and their mimetics on human bronchi from PH patients are unknown. Here, we have compared relaxant effects of several PGI2 -mimetics approved for treating PH Group I with several PGE2 -mimetics, in bronchial preparations derived from PH Group III and control patients. Relaxation of bronchial muscle was assessed in samples isolated from control and PH Group III patients. Expression of prostanoid receptors was analysed by western blot and real-time PCR, and endogenous PGE2 , PGI2 , and cAMP levels were determined by ELISA. Maximal relaxations induced by different EP4 receptor agonists (PGE2 , L-902688, and ONO-AE1-329) were decreased in human bronchi from PH patients, compared with controls. However, maximal relaxations produced by PGI2 -mimetics (iloprost, treprostinil, and beraprost) were similar for both groups of patients. Both EP4 and IP receptor protein and mRNA expressions were significantly lower in human bronchi from PH patients. cAMP levels significantly correlated with PGI2 but not with PGE2 levels. The PGI2 -mimetics retained maximal bronchodilation in PH Group III patients, whereas bronchodilation induced by EP4 receptor agonists was decreased. Restoration of EP4 receptor expression in airways of PH Group III patients with respiratory diseases could bring additional therapeutic benefit.

Investigation of association of chemical profiles with the tracheobronchial relaxant activity of Chinese medicinal herb Beimu derived from various Fritillaria species

Ethnopharmacological relevanceFritillariae Bulbus (Beimu in Chinese) is derived from the bulbus of many Fritillaria species (family Liliaceae), which has been used as an antitussive herb in traditional Chinese medicine for more than 2000 years. Due to the complexity of plant origins and significant variations in chemical profiles, the characterization of the profile of the major bioactive constituents and its association with pharmacological activity are important for the quality control of Beimu herbs from different origins. Aim of the studyThis study aims to investigate the distribution of major bioactive isosteroidal alkaloids in Beimu herbs of different origins and its correlation with the tracheobronchial relaxant activity. MethodsQuantification of 7 main bioactive 5α-cevanine isosteroidal alkaloids, including ebeiedine, ebeiedinone, hupehenine, isoverticine, verticine, verticinone and imperialine, in 23 Fritillaria species was performed using gas chromatography. The relaxant effect of different extracts of 4 commonly used Beimu herbs, namely Zhe-Beimu (F. thunbergii Miq.), Chuan-Beimu (F. cirrhosa D. Don), Hubei-Beimu (F. hupehensis Hsiao et K. C. Hsia) and Yi-Beimu (F. pallidiflora Schrenk), was evaluated using rat isolated tracheal and bronchial preparations pre-contracted with carbachol, the well established in vitro antitussive model. ResultsAmongst 23 Fritillaria species detected, significant variations of the types and quantities of 7 major isosteroidal alkaloids were determined, which served as an important indicator for the classification of different Beimu herbs with distinct geographic distributions. Based on the type and quantity of these alkaloids, different origins of Beimu could be clearly clustered into several subgroups by principal component analysis. Furthermore, both crude alkaloid and water extracts of all 4 Beimu herbs showed a dose-dependent tracheobronchial relaxation with different potencies. The total content of alkaloids (weight adjusted based on the activity of individual alkaloids) in Beimu extracts significantly correlated with their tracheobronchial relaxation effects (r2 > 0.9, p < 0.001). ConclusionsThe results demonstrated that the differences in chemical profile of major bioactive isosteroidal alkaloids and pharmacological activity of Beimu could be incorporated into a simple and unified method for quality control and potential prediction of activity of Beimu herbs from different origins.

Characterization of V0162, a new long-acting antagonist at human M3 muscarinic acetylcholine receptors

The anticholinergic properties of the mequitazine enantiomer V0162 make it a drug candidate for the treatment of chronic obstructive airway diseases. Here, we compared V0162’s in vitro pharmacological activity at recombinant human M3 muscarinic acetylcholine receptors (hM3Rs) with that of other anticholinergics, using (i) a radioligand binding assay, (ii) a functional reporter gene assay and (iii) a bronchoconstriction inhibition assay on human bronchial preparations. V0162 had high affinity for hM3Rs, with a pKi varying from 9.01 after a 2h incubation to 9.21 after 23h. The other mequitazine enantiomer (V0114) was less potent. V0162 displayed rapid off-kinetics and a biphasic time course of binding. V0162 was found to be an antagonist behaving as an inverse agonist for hM3R-mediated reporter gene activation, with much the same efficacy as atropine, ipratropium and tiotropium. However, in contrast to ipratropium and atropine, V0162’s inhibitory potency was only slightly affected by compound washout. V0162 antagonized acetylcholine-mediated contractions in a human bronchial preparation; the pA2 values increased with the incubation time (up to 2h). Moreover, there was a progressive increase in V0162’s ability to inhibit electrically-induced contractions, which persisted after compound washout. In conclusion, V0162 is the most active mequitazine enantiomer at hM3Rs and shows a complex pattern of binding to the membrane compartment. These particular features may be of therapeutic value when persistent antagonism at hM3Rs is required.

ASM-024, a piperazinium compound, promotes the in vitro relaxation of β2-adrenoreceptor desensitized tracheas.

Inhaled β2-adrenoreceptor agonists are widely used in asthma and chronic obstructive pulmonary disease (COPD) for bronchoconstriction relief. β2-adrenoreceptor agonists relax airway smooth muscle cells via cyclic adenosine monophosphate (cAMP) mediated pathways. However, prolonged stimulation induces functional desensitization of the β2-adrenoreceptors (β2-AR), potentially leading to reduced clinical efficacy with chronic or prolonged administration. ASM-024, a small synthetic molecule in clinical stage development, has shown activity at the level of nicotinic receptors and possibly at the muscarinic level and presents anti-inflammatory and bronchodilator properties. Aerosolized ASM-024 reduces airway resistance in mice and promotes in-vitro relaxation of tracheal and bronchial preparations from animal and human tissues. ASM-024 increased in vitro relaxation response to maximally effective concentration of short—acting beta-2 agonists in dog and human bronchi. Although the precise mechanisms by which ASM-024 promotes airway smooth muscle (ASM) relaxation remain unclear, we hypothesized that ASM-024 will attenuate and/or abrogate agonist-induced contraction and remain effective despite β2-AR tachyphylaxis. β2-AR tachyphylaxis was induced with salbutamol, salmeterol and formoterol on guinea pig tracheas. The addition of ASM-024 relaxed concentration-dependently intact or β2-AR desensitized tracheal rings precontracted with methacholine. ASM-024 did not induce any elevation of intracellular cAMP in isolated smooth muscle cells; moreover, blockade of the cAMP pathway with an adenylate cyclase inhibitor had no significant effect on ASM-024-induced guinea pig trachea relaxation. Collectively, these findings show that ASM-024 elicits relaxation of β2-AR desensitized tracheal preparations and suggest that ASM-024 mediates smooth muscle relaxation through a different target and signaling pathway than β2-adrenergic receptor agonists. These findings suggest ASM-024 could potentially provide clinical benefit when used adjunctively with inhaled β2-adrenoreceptor agonists in those patients exhibiting a reduced response to their chronic use.

Evaluation of different anti-asthmatic drugs on cooling-induced bronchoconstriction

Inhalation of cold air is a well-recognized cause of bronchoconstriction in asthmatics. Sudden changes in weather temperature outdoors and indoors due to the extensive use of air conditioning in Kuwait is an important existing problem. The aim of this study was to determine the most effective anti-asthmatic drugs for preventing or reversing cooling-induced contraction (CIC). We recorded isometric tension from tracheal strips, and bronchiolar rings were prepared from male Merino sheep in organ baths during stepwise cooling. CIC was tested before and after addition of various standard agents. Disodium cromoglycate (DSG), methyl prednisolone, atropine, aminophylline, isoprenaline and adrenaline were examined in two cases. The first was before cooling and the second was after cooling induced the maximum bronchoconstriction. Cooling to 20°C induced a rapid and reproducible contraction in ovine tracheal and bronchial preparations. On readjustment to 37°C, the tone returned rapidly to basal level. DSG, methyl prednisolone and atropine did not prevent or reverse the CIC. Aminophylline prevented CIC by 70%. It inhibited the peak of cooling response by 70%. β-agonists (isoprenaline and adrenaline) abolished the CIC, and they also rapidly and totally reversed the cooling effect when added at the peak of bronchoconstriction. These results proved that β-agonists are the drugs of choice in preventing the bronchoconstriction before exposure to cold environment and also completely reversing the bronchoconstriction induced after cooling exposure.

Bronchodilatory and Anti-Inflammatory Effects of ASM-024, a Nicotinic Receptor Ligand, Developed for the Treatment of Asthma

Conventional asthma and COPD treatments include the use of bronchodilators, mainly β2-adrenergic agonists, muscarinic receptor antagonists and corticosteroids or leukotriene antagonists as anti-inflammatory agents. These active drugs are administered either separately or given as a fixed-dose combination medication into a single inhaler. ASM-024, a homopiperazinium compound, derived from the structural modification of diphenylmethylpiperazinium (DMPP), has been developed to offer an alternative mechanism of action that could provide symptomatic control through combined anti-inflammatory and bronchodilator properties in a single entity. A dose-dependent inhibition of cellular inflammation in bronchoalveolar lavage fluid was observed in ovalbumin-sensitized mice, subsequently treated for 3 days by nose-only exposure with aerosolized ASM-024 at doses up to 3.8 mg/kg (ED50 = 0.03 mg/kg). The methacholine ED250 values indicated that airway hyperresponsivenness (AHR) to methacholine decreased following ASM-024 administration by inhalation at a dose of 1.5 mg/kg, with a value of 0.145±0.032 mg/kg for ASM 024-treated group as compared to 0.088±0.023 mg/kg for untreated mice. In in vitro isometric studies, ASM-024 elicited dose-dependent relaxation of isolated mouse tracheal, human, and dog bronchial preparations contracted with methacholine and guinea pig tracheas contracted with histamine. ASM-024 showed also a dose and time dependant protective effect on methacholine-induced contraction. Overall, with its combined anti-inflammatory, bronchodilating and bronchoprotective properties, ASM-024 may represent a new class of drugs with a novel pharmacological approach that could prove useful for the chronic maintenance treatment of asthma and, possibly, COPD.

Effect of Fenspiride on Bronchial Smooth Muscle of Rats with Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is among the leading causes of morbidity and mortality worldwide. Glucocorticoids are currently the most applicable anti-inflammatory treatment for COPD. However, a subset of COPD subjects is relatively insensitive to this treatment. Fenspiride, a non-corticosteroid anti-inflammatory drug, has been described to have beneficial effects in patients with COPD, although the mechanism of its action is not well known. The effect of fenspiride on contractile activity of bronchial smooth muscle was studied in a rat model of COPD induced by long-term exposure of the animals to nitrogen dioxide (NO2). Contractile activity of bronchial smooth muscle was evaluated in vitro. Isometric contraction of bronchial preparations was measured following electrical stimulation. Fenspiride administration to rats during the acute stage of COPD (15 days of NO2 exposure) prevented the bronchial constriction induced by NO2. The bronchodilator effect of a low-dose of fenspiride (0.15 mg/kg) was mediated by interaction with the nerve endings of capsaicin-sensitive C-fibers. Interaction of fenspiride with C-fibers was shown to prevent initiation of neurogenic inflammation, as evidenced by lack of COPD-like structural changes in the lungs. The bronchodilator effect of a high-dose of fenspiride (15 mg/kg) was mediated not only by the afferent component, but also involved a direct relaxing effect on smooth muscle cells. The anti-inflammatory and bronchodilator effects of a low-dose of fenspiride may be used for prevention of COPD development in individuals from high-risk cohorts exposed to aggressive environmental factors.

Counterpoint: Alterations in airway smooth muscle phenotype do not cause airway hyperresponsiveness in asthma

We have been assigned the task of showing that “alterations in airway smooth muscle phenotype DO NOT cause the airways hyperresponsiveness of asthma.” In the following paragraphs we will briefly review the overwhelming lack of evidence that any fundamental change in the intrinsic properties of

PGE2 receptor (EP4) agonists: Potent dilators of human bronchi and future asthma therapy?

BackgroundAsthma and chronic obstructive pulmonary disease are characterized by inappropriate constriction of the airway smooth muscle. In this context, the physiological response of the human airways to selective relaxant agonists like PGE2 is highly relevant. The aim of this study was thus to characterize the PGE2 receptor subtypes (EP2 or EP4) involved in the relaxation of human bronchial preparations. MethodsHuman bronchial preparations cut as rings were mounted in organ baths for isometric recording of tension and a pharmacological study was performed using selective EP2 or EP4 ligands. ResultsIn the presence of a thromboxane TP receptor antagonist and indomethacin, PGE2 induced the relaxation of human bronchi (Emax = 86 ± 04% of papaverine response; pEC50 value = 7.06 ± 0.13; n = 6). This bronchodilation was significantly blocked by a selective EP4 receptor antagonist (GW627368X, 1 and 10 μmol/L) with a pKB value of 6.38 ± 0.19 (n = 5). In addition, the selective EP4 receptor agonists (ONO-AE1-329; L-902688), but not the selective EP2 receptor agonist (ONO-AE1-259), induced potent relaxation of bronchial preparations pre-contracted with histamine or anti-IgE. ConclusionPGE2 and EP4 agonists induced potent relaxations of human bronchial preparations via EP4 receptor. These observations suggest that EP4 receptor agonists could constitute therapeutic agents to treat the increased airway resistance in asthma.

In vitro Tracheobronchial Relaxation of Fritillaria Alkaloids

Aim Beimu (Bulbus Fritillariae) is a commonly used anti-tussive traditional Chinese herbal medicine and the major Fritillaria alkaloids in the herb are believed to be responsible for its antitussive activity. However, the detailed underlying mechanism and potency of individual Fritillaria alkaloids are still not very clear. Methods In the present study, we investigated and compared the relaxant effect of five major Fritillaria alkaloids [imperialine (IMP), verticine (VER), verticinone (VERN), ebeiedine (EBE) and puqietinone (PUQ)] using rat isolated tracheal and bronchial preparations pre-contracted with carbachol. Results All five Fritillaria alkaloids caused a concentration-dependent relaxation of both tracheal and bronchial preparations with the relative relaxing potency of IMP < VER ≅ VERN < EBE < PUQ. Amongst all five alkaloids tested, IMP (an isosteroidal Fritillaria alkaloid with a cis-configuration in rings D and E) was found to be the most potent; whereas PUQ (a steroidal Fritillaria alkaloid) was the least effective one. Furthermore, three Fritillaria alkaloids, namely IMP, VER and VERN (≥ 1 μmol·L −1) were capable of eliciting parallel rightward shifts of the carbachol concentration-response curve, demonstrating a competitive antagonism in muscarinic pathway. In addition, the suppression of carbachol-induced contraction caused by all five isosteroidal Fritillaria alkaloids was also partly due to the inhibition of influx of calcium ions. Conclusion The results demonstrated that the major isosteroidal Fritillaria alkaloids might be the most active constituents responsible for the anti-tussive activity of herbal Beimu with the mechanisms of competitive antagonism of muscarinic pathway and also the inhibition of influx of calcium ions.

Three-Dimensional Nuclear Luminance Analysis in Well-Differentiated Adenocarcinoma of the Lung

Objective: Well-differentiated papillary adenocarcinoma of the lung (G1 cancer cells) is difficult to distinguish from benign bronchial columnar epithelial cells with reactive atypia (benign cells) in many cases because nuclear atypia is mild. We focused on the 3-dimensional presence of nuclei in cell smears. Several images focused on the nucleus were acquired, and the nuclear luminance was measured and analyzed. Study Design: One hundred G1 cancer cells and benign cells (nuclei), respectively, were selected from those on a bronchial brushing preparation for cytology. Images of 41 layers were acquired at 0.25-µm intervals in each cell, and the nuclear luminance was measured (a total of 8,400 images). Results: There were more focus positions in the G1 cancer cell nuclei, showing a 3-dimensional nucleus, compared to benign cells, and the 3-dimensional variation in the coefficient of variation (CV) of nuclear luminance at the focus position was smaller in G1 cancer than in benign cells, showing a significant difference. Conclusion: The G1 cancer cells’ nuclear structure was more 3-dimensional, and the chromatin distribution was homogeneous. The three-dimensional variation in the nuclear luminance CV could be numerically presented, which might be an objective index for cancer diagnosis.

A possible site of action of nicotine in the bronchial smooth muscle preparation of guinea-pig.

A possible site of action of nicotine in the bronchial smooth muscle preparation of guinea-pig.

Adverse events associated with treatment of latent tuberculosis in the general population

Guidelines recommend treatment of latent tuberculosis in patients at increased risk for active tuberculosis. Studies investigating the association of therapy with serious adverse events have not included the entire treated population nor accounted for comorbidities or occurrence of similar events in the untreated general population. Our objective was to estimate the risk of adverse events requiring hospital admission that were associated with therapy for latent tuberculosis infection in the general population. Using administrative health data from the province of Quebec, we created a historical cohort of all residents dispensed therapy for latent tuberculosis between 1998 and 2003. Each patient was matched on age, sex and postal region with two untreated residents. The observation period was 18 months (from 6 months before to 12 months after initiation of therapy). The primary outcome was hospital admission for therapy-associated adverse events. During the period of observation, therapy for latent tuberculosis was dispensed to 9145 residents, of whom 95% started isoniazid and 5% started rifampin. Pretreatment comorbid illness was significantly more common among patients receiving such therapy compared with the matched untreated cohort. Of all patients dispensed therapy, 45 (0.5%) were admitted to hospital for a hepatic event compared with 15 (0.1%) of the untreated patients. For people over age 65 years, the odds of hospital admission for a hepatic event among patients treated for latent tuberculosis infection was significantly greater than among matched untreated people after adjustment for comorbidities (odds ratio [OR] 6.4, 95% CI 2.2-18.3). Excluding patients with comorbid illness, there were two excess admissions to hospital for hepatic events per 100 patients initiating therapy compared with the rate among untreated people over 65 years (95% CI 0.1-3.87). The risk of adverse events requiring hospital admission increased significantly among patients over 65 years receiving treatment for latent tuberculosis infection. The decision to treat latent tuberculosis infection in elderly patients should be made after careful consideration of risks and benefits.

Different effects of smoke from heavy and light cigarettes on the induction of bronchial smooth muscle hyperresponsiveness in rats

Cigarette smoking is one of the main risk factors in the development of chronic obstructive pulmonary disease (COPD). It has been suggested that an augmented agonist-induced, RhoA mediated Ca²⁺ sensitization is responsible for the enhanced bronchial smooth muscle contraction induced by cigarette smoking. In the present study, to determine whether or not these phenomena are dependent on the degree of exposure to the components of cigarette smoke, we examined the effects of exposure to mainstream smoke derived from either light or heavy cigarettes on both the contractile responsiveness and the expression of RhoA in bronchial smooth muscle. Male Wistar rats were exposed to mainstream cigarette smoke for 2 hr/day for 2 weeks. Twenty-four hr after the last cigarette smoke exposure, we measured isometrical contractions of the bronchial smooth muscle. The concentration-response curve to ACh was significantly shifted upward after heavy cigarette smoke (HCS) exposure, whereas no significant difference was observed in the case of light cigarette smoke (LCS) exposure compared with control rats. No significant difference in K⁺ responsiveness was observed between the groups. The expression of RhoA protein in bronchial preparations from rats repeatedly exposed to HCS, but not to LCS, was significantly increased as compared with that of the control animals. On the other hand, inhalation of nicotine had no effect on either the ACh- and high K⁺ depolarization-induced contractions or the expression of RhoA protein. The increased expression of RhoA seems to have an important role in the augmented contractile responses of the airways in rats, a characteristic feature of early COPD.

Isolating bronchial epithelial cell preparations from gross lung specimens

Tissue microdissection is appropriate for separating pure cells from heterogeneous tissues. Recently, we have focused on whole genome DNA methylation patterns of lung squamous cell carcinoma (SCC) and needed to obtain the appropriate counterpart cells of lung SCC. However, in some regions of human tissues, such as in bronchial epithelium, it is difficult to apply tissue microdissection as a means to isolate pure cells from a heterogenous mixture of cells. Accordingly, we developed the pop brush method to retrieve sufficient amounts of pure bronchial epithelium from gross lung specimens, and this method enables us to study epigenetic variations of lung SCC.

Isolating bronchial epithelial cell preparations from gross lung specimens

Tissue microdissection is appropriate for separating pure cells from heterogeneous tissues. Recently, we have focused on whole-genome DNA methylation patterns of lung squamous cell carcinoma (SCC) and needed to obtain the appropriate counterpart cells of lung SCC. However, in some regions of human tissues, such as in bronchial epithelium, it is difficult to apply tissue microdissection as a means to isolate pure cells from a heterogenous mixture of cells. Accordingly, we developed the pop brush method to retrieve sufficient amounts of pure bronchial epithelium from gross lung specimens and this method enables us to study epigenetic variations of lung SCC.

Bronchorelaxant property of African potato' (Hypoxis hemerocallidea corm) aqueous extract in vitro

This study was undertaken to investigate the bronchorelaxant effect of Hypoxis hemerocallidea corm ('African potato') aqueous extract (APE) on spasmogen-provoked contractions of guinea-pig isolated tracheal smooth muscle preparations. APE (25-400 mg/ml) relaxed spasmogen (histamine-, carbachol- and potassium-)-induced contractions of the isolated tracheal muscle preparations in a concentration-dependent manner. The relaxant effects of APE on spasmogen-evoked contractions of the tracheal muscle preparations were not altered by bath-applied propranolol (0.1-5.0 microg/ml), which markedly inhibited or completely abolished the relaxant effects of isoprenaline (0.1-5.0 microg/ml). Although the precise mechanism of the bronchorelaxant effect of APE could not be established in the present study, it is unlikely that the herb's aqueous extract stimulates the beta(2)-adrenoceptors present on the bronchial smooth muscles to produce its bronchodilatation. The finding that APE significantly relaxed (P<0.05) histamine-, carbachol- and high potassium ion concentration (K(+), 80 mM)-induced contractions of guinea-pig isolated bronchial muscle preparations appears to suggest that the bronchospasmolytic effect of the plant's extract is probably not mediated through a specific receptor, but rather, probably mediated via a non-specific bronchospasmolytic mechanism.

Novel human bronchial epithelial cell lines for cystic fibrosis research

Immortalization of human bronchial epithelial (hBE) cells often entails loss of differentiation. Bmi-1 is a protooncogene that maintains stem cells, and its expression creates cell lines that recapitulate normal cell structure and function. We introduced Bmi-1 and the catalytic subunit of telomerase (hTERT) into three non-cystic fibrosis (CF) and three DeltaF508 homozygous CF primary bronchial cell preparations. This treatment extended cell life span, although not as profoundly as viral oncogenes, and at passages 14 and 15, the new cell lines had a diploid karyotype. Ussing chamber analysis revealed variable transepithelial resistances, ranging from 200 to 1,200 Omega.cm(2). In the non-CF cell lines, short-circuit currents were stimulated by forskolin and inhibited by CFTR(inh)-172 at levels mostly comparable to early passage primary cells. CF cell lines exhibited no forskolin-stimulated current and minimal CFTR(inh)-172 response. Amiloride-inhibitable and UTP-stimulated currents were present, but at lower and higher amplitudes than in primary cells, respectively. The cells exhibited a pseudostratified morphology, with prominent apical membrane polarization, few apoptotic bodies, numerous mucous secretory cells, and occasional ciliated cells. CF and non-CF cell lines produced similar levels of IL-8 at baseline and equally increased IL-8 secretion in response to IL-1beta, TNF-alpha, and the Toll-like receptor 2 agonist Pam3Cys. Although they have lower growth potential and more fastidious growth requirements than viral oncogene transformed cells, Bmi-1/hTERT airway epithelial cell lines will be useful for several avenues of investigation and will help fill gaps currently hindering CF research and therapeutic development.

Isolated porcine bronchi provide a reliable model for development of bronchodilator anti‐muscarinic agents for human use

In human airways, muscarinic acetylcholine receptors (mAChRs) exert a predominant role in the control of airways resistance and anti-muscarinic agents are currently included in the pharmacological treatment of chronic obstructive pulmonary disease (COPD). However, the development of more effective mAChR antagonists is hampered by considerable species variability in the ultrastrucural and functional control of airway smooth muscle, making extrapolation of any particular animal model questionable. This study was designed to characterize the mAChRs in a bronchial preparation from pigs, animals considered to provide close models of human biology. Smooth muscle bronchial strips were examined by electron microscopy in order to compare their neuromuscular structure with that of human bronchi and used to study the affinity of a series of selective mAChR antagonists, estimated as pKis in competition binding assays with NMS and pA2, by Schild analysis, in contractile experiments. Pharmacodynamic binding parameters and affinity profiles of a series of antagonists were consistent with the presence of a majority of M2 mAChRs along with a minor population of M3 mAChRs. Functionally, the highly significant correlation between postjunctional pA2 affinities and corresponding affinity constants at human recombinant M1-M5 subtypes indicated that smooth muscle contraction in porcine bronchi, as in human bronchi, was dependent on the M3 subtype. Based on the characterization of mAChRs, isolated porcine bronchi provide an additional experimental model for development of mAChR antagonists for the treatment of human airway dysfunctions.