Effects of Long-Acting Muscarinic Antagonists on Promoting Ciliary Function in Airway Epithelium

Background Mucociliary clearance (MCC) is an essential defense mechanism in airway epithelia for removing pathogens from the respiratory tract. Impaired ciliary functions and MCC have been demonstrated in asthma and chronic obstructive pulmonary disease (COPD). Long-acting muscarinic antagonists (LAMAs) are a major class of inhaled bronchodilators, which are used for treating asthma and COPD; however, the effects of LAMAs on ciliary function remain unclear. This study aimed to identify the effects of LAMAs on airway ciliary functions. Methods Wild-type BALB/c mice were treated with daily intranasal administrations of glycopyrronium for 7 days, and tracheal samples were collected. Cilia-driven flow and ciliary activity, including ciliary beat frequency (CBF), ciliary beating amplitude, effective stroke velocity, recovery stroke velocity and the ratio of effective stroke velocity to recovery stroke velocity, were analyzed by imaging techniques. Using in vitro murine models, tracheal tissues were transiently cultured in media with/without LAMAs, glycopyrronium or tiotropium, for 60 min. Cilia-driven flow and ciliary activity were then analyzed. Well-differentiated normal human bronchial epithelial (NHBE) cells were treated with glycopyrronium, tiotropium, or vehicle for 60 min, and CBF was evaluated. Several mechanistic analyses were performed. Results Intranasal glycopyrronium administration for 7 days significantly increased cilia-driven flow and ciliary activity in murine airway epithelium. In the murine tracheal organ culture models, treatment with glycopyrronium or tiotropium for 60 min significantly increased cilia-driven flow and ciliary activity in airway epithelium. Further, we confirmed that 60-min treatment with glycopyrronium or tiotropium directly increased CBF in well-differentiated NHBE cells. In the mechanistic analyses, neither treatment with glycopyrronium nor tiotropium affected intracellular calcium ion concentrations in well-differentiated NHBE cells. Glycopyrronium did not increase protein kinase A activity in well-differentiated NHBE cells. Moreover, glycopyrronium had no effect on extracellular adenosine triphosphate concentration. Conclusions LAMAs exert a direct effect on airway epithelium to enhance ciliary function, which may improve impaired MCC in asthma and COPD. Further investigations are warranted to elucidate the underlying mechanisms of the effects of LAMAs on the promotion of airway ciliary function.

Anatomical Variations of Uncinate Process in a Tertiary Care Hospital of a Coastal city in Karnataka

Introduction: Superior attachment of uncinate process is the most important anatomical landmark in frontal recess surgery. The uncinate process is an integral struc­ture of osteomeatal complex and prevents the direct contact of the inspired air with the maxillary sinus. It acts as a shield and also plays a role in muco-ciliary activity. Anatomic variations of the uncinate process have surgical implications. Aim: This study was done to know the different variations of superior attachment of uncinate process. Materials and Methods: In this retrospective observational descriptive study, Computed Tomography (CT) scans of Para Nasal Sinuses (PNS) of 256 patients from Sept 2018 to May 2020 were studied. The results were expressed in percentages and proportions. Results: Among 256 CT images, 139 belonged to males and 117 females. In the CT films examined, on the right side, the most common attachment of uncinate was to lamina papyracea which was (64.8%) followed by skull base (19.5%) and to the middle turbinate(15.6%). Similar findings were seen on left side. Conclusion: Uncinate process shows different variations in its superior attachment. Superior attachment to lamina papyracea was the most common attachment of uncinate in our study.

In Vitro Ciliotoxicity and Cytotoxicity Testing of Repeated Chronic Exposure to Topical Nasal Formulations for Safety Studies

Certain active drugs and excipients of nasal formulations may impair ciliary function and mucociliary clearance. The ciliary beat frequency (CBF) is a key parameter for determining mucociliary clearance rate, and in vitro assessments of CBF have proven to be accurate and reproducible. Since topical nasal formulations are applied with repeated doses, it is essential to elucidate their chronic, as opposed to acute, effect on mucociliary clearance and nasal mucosa. The aim of this study was to assess for the first time the ciliotoxicity and cytotoxicity of nasal sprays intended for chronic treatment (with repeated doses) using a previously designed set-up for CBF measurements. For 2 weeks, the 3D nasal MucilAir™ in vitro models were treated daily with undiluted or clinically relevant doses of mometasone nasal spray, placebo nasal spray, culture medium, or they were untreated. We demonstrated a dose-dependent and time-dependent (cumulative) effect of the nasal sprays on ciliary activity and cytotoxicity using CBF measurements and ultrastructural analysis, respectively. Our results indicate that repeated administration of clinically relevant doses of mometasone nasal spray is safe for in vivo use, which is in good agreement with a previous clinical study. Overall, our study suggests that such in vitro assays have great potential for topical nasal drug screening.

Bicc1 and Dicer regulate left-right patterning through post-transcriptional control of the Nodal inhibitor Dand5

Rotating cilia at the vertebrate left-right organizer (LRO) generate an asymmetric leftward flow, which is sensed by cells at the left LRO margin. Ciliary activity of the calcium channel Pkd2 is crucial for flow sensing. How this flow signal is further processed and relayed to the laterality-determining Nodal cascade in the left lateral plate mesoderm (LPM) is largely unknown. We previously showed that flow down-regulates mRNA expression of the Nodal inhibitor Dand5 in left sensory cells. De-repression of the co-expressed Nodal, complexed with the TGFß growth factor Gdf3, drives LPM Nodal cascade induction. Here, we show that post-transcriptional repression of dand5 is a central process in symmetry breaking of Xenopus, zebrafish and mouse. The RNA binding protein Bicc1 was identified as a post-transcriptional regulator of dand5 and gdf3 via their 3′-UTRs. Two distinct Bicc1 functions on dand5 mRNA were observed at pre- and post-flow stages, affecting mRNA stability or flow induced translational inhibition, respectively. To repress dand5, Bicc1 co-operates with Dicer1, placing both proteins in the process of flow sensing. Intriguingly, Bicc1 mediated translational repression of a dand5 3′-UTR mRNA reporter was responsive to pkd2, suggesting that a flow induced Pkd2 signal triggers Bicc1 mediated dand5 inhibition during symmetry breakage.

Effects of Long-acting Muscarinic Antagonists on Promoting Ciliary Function in Airway Epithelium

BackgroundMucociliary clearance (MCC) is an essential defense mechanism in airway epithelia for removing pathogens from the respiratory tract. Impaired ciliary functions and MCC have been demonstrated in asthma and chronic obstructive pulmonary disease (COPD). Long-acting muscarinic antagonists (LAMAs) are a major class of inhaled bronchodilators, which are used for treating asthma and COPD; however, the effects of LAMAs on ciliary function remain unclear. This study aimed to identify the effects of LAMAs on airway ciliary functions.MethodsWild-type BALB/c mice were treated with daily intranasal administrations of glycopyrronium for 7 days, and tracheal samples were collected. Cilia-driven flow and ciliary activity, including ciliary beat frequency (CBF), ciliary beating amplitude, effective stroke velocity, recovery stroke velocity and the ratio of effective stroke velocity to recovery stroke velocity, were analyzed by imaging techniques. Using in vitro murine models, tracheal tissues were transiently cultured in media with/without LAMAs, glycopyrronium or tiotropium, for 60 min. Cilia-driven flow and ciliary activity were then analyzed. Well-differentiated normal human bronchial epithelial (NHBE) cells were treated with glycopyrronium, tiotropium, or vehicle for 60 min, and CBF was evaluated. Several mechanistic analyses were performed.ResultsIntranasal glycopyrronium administration for 7 days significantly increased cilia-driven flow and ciliary activity in murine airway epithelium. In the murine tracheal organ culture models, treatment with glycopyrronium or tiotropium for 60 min significantly increased cilia-driven flow and ciliary activity in airway epithelium. Further, we confirmed that 60-min treatment with glycopyrronium or tiotropium directly increased CBF in well-differentiated NHBE cells. In the mechanistic analyses, neither treatment with glycopyrronium nor tiotropium affected intracellular calcium ion concentrations in well-differentiated NHBE cells. Glycopyrronium did not increase protein kinase A activity in well-differentiated NHBE cells. Moreover, glycopyrronium had no effect on extracellular adenosine triphosphate concentration.ConclusionsLAMAs exert a direct effect on airway epithelium to enhance ciliary function, which may improve impaired MCC in asthma and COPD. Further investigations are warranted to elucidate the underlying mechanisms of the effects of LAMAs on the promotion of airway ciliary function.

Sinonasal effects of external dacryocystorhinostomy

Objective External dacryocystorhinostomy is thought to cause mucociliary dysfunction by damaging the mucosa, in turn affecting ciliary activity and mucus quality. This study investigated the effect of external dacryocystorhinostomy on sinonasal function. Methods Patients scheduled for unilateral external dacryocystorhinostomy who underwent endoscopic nasal examination and paranasal sinus computed tomography were included in this study. A saccharine test was performed on the planned surgical side and the mucociliary clearance time was determined. The sinonasal quality of life was measured in all patients, pre-operatively and at six months post-operatively, using the Sino-Nasal Outcome Test-22. The Lund–Kennedy endoscopic score was also determined in all patients, both pre- and post-operatively. Results The study comprised 28 patients (22 females and 6 males). A statistically significant difference was found between the pre- and post-operative saccharine test results (p = 0.006), but not between the pre- and post-operative Sino-Nasal Outcome Test-22 scores (p > 0.05). Conclusion This study is one of only a few to investigate the effect of external dacryocystorhinostomy on sinonasal function. The results showed that external dacryocystorhinostomy impairs mucociliary clearance. The surgical procedure is well tolerated and does not significantly change nasal symptom scores.

The impact of zinc supplementation on the outcome of endoscopic sinus surgery and ciliary function of the nasal mucosa in children with chronic rhinosinusitis

Несмотря на указания на роль цинка в функции реснитчатого эпителия, данные относительно влияния коррекции обмена цинка на цилиарную функцию у пациентов с хроническим риносинуситом отсутствуют. Целью настоящего исследования явилась оценка эффективности хирургического лечения, активности мукоцилиарного аппарата, а также местной воспалительной реакции слизистой оболочки носа в послеоперационном периоде у детей с хроническим риносинуситом на фоне применения цинка. Методы. Обследовано 192 ребенка с хроническим риносинуситом, в лечении которых применялась эндоскопическая риносинусохирургия. Из них 131 ребенок в послеоперационном периоде получал стандартные назначения, тогда как 61 ребенок дополнительно получал цинк в суточной дозе 10 мг в течение 90 дней. Оценка концентрации цинка в сыворотке крови осуществлялась методом ИСП-МС. Для определения функции цилий использована видеоцитоморфометрия. Определение эффективности лечения осуществлялось с использованием опросника SNOT-20, а также шкал Лунд-Кеннеди и Лунд-Маккей. Результаты. Проведение эндоскопической операции приводило к достоверному снижению значений шкал SNOT-20, Лунд-Кеннеди и Лунд-Маккей у пациентов вне зависимости от приема цинка. В то же время, пациенты, принимавшие цинк, характеризовались достоверно меньшим риском ревизионной хирургии. Цинк также оказывал значительное влияние на функционирование реснитчатого эпителия. В частности, к 12-му месяцу наблюдения количество клеток с подвижными цилиями, частота биения цилий, длина цилий и выживаемость клеток у пациентов, принимавших цинк, превышала соответствующие показатели в контрольной группе. Повышение уровня цинка в организме также сопровождалось многократным снижением количества инфильтрирующих слизистую оболочку нейтрофилов и лимфоцитов. Заключение. Предполагается, что цинк ускоряет репаративные процессы в слизистой оболочке носа и обладает противовоспалительным действием. Despite the presence of certain indications of the role of zinc in ciliated epithelium functioning, data on the potential effect of Zn supplementation in ciliary function in patients with chronic rhinosinusitis are absent. The aim of this study was to evaluate the efficiency of surgical treatment, ciliary activity, as well as local inflammation of nasal mucosa in children with chronic rhinosinusitis undergoing functional endoscopic surgery. Methods. 192 pediatric patients with chronic rhinosinusitis were examined. 131 patients received standard postoperative prescriptions, whereas 61 children received 10 mg Zn daily for 90 days. Serum Zn concentrations were measured by inductively coupled plasma mass spectrometry. Ciliary function was evaluated by video cytomorphometry. Surgery efficiency was assessed with a SNOT-20 questionnaire, as well as with Lund-Kennedy and Lund-Mackay scales. Results. Functional endoscopic sinus surgery resulted in a significant decrease in total SNOT-20, Lund-Kennedy, and Lund-Mackay scores independent of Zn supplementation. At the same time, Zn supplemented patients had a significantly lower risk of revision surgery. Zn also had a significant impact on ciliary function. Specifically, up to the 12th mo postoperatively, Zn supplementation resulted in higher number of cells with motile cilia, ciliary beat frequency, ciliary length, and cell viability as compared to controls. Increased Zn status was also associated with a manyfold decrease in mucosal neutrophil and lymphocyte infiltration. Conclusions. It is proposed that Zn enhances reparative processes in nasal mucosa and possesses anti-inflammatory activity.

A Quantitative Interspecies Comparison of The Respiratory Mucociliary Clearance Mechanism

Background: Collectively coordinated ciliary activity constantly propels the airway surface liquid, which lines the luminal surface of the vertebrate respiratory system, in cranial direction – constituting mucociliary clearance, the primary defence mechanism of our airways. Our contemporary understanding on how the quantitative characteristics of the metachronal wave field determines the resulting mucociliary transport is still limited, which is partly due to the sparse availability of quantitative observational data. Methods: We employed high-speed video reflection contrast microscopy to simultaneously image and quantitatively characterize the metachronal wave field as well as the mucociliary transport in excised bovine, porcine, ovine, lapine, turkey and ostrich samples of the luminal tracheal wall. Advanced image processing techniques were used to determine the ciliary beating frequency (CBF), the velocity and the wavelength of the metachronal wave as well as the mucociliary transport velocity. Results: The mucociliary transport direction was found to strongly correlate with the mean wave propagation direction in all six species. The CBF yielded similar values (10−15 Hz) for all six species. Birds were found to exhibit considerably higher transport speeds (130−260 μm/s) than mammals (20−80 μm/s). While the average transport direction significantly deviates from the tracheal long axis (TLA) in mammals, no significant deviation from the TLA was found in birds. In comparison to mammals, longer metachronal wavelengths were found in birds. Finally, the metachronal waves were found to propagate at about 4−8 times the speed of mucociliary transport in mammals, whereas the metachronal waves propagate at about the speed of mucociliary transport in birds. Conclusions: The tracheal mucociliary clearance mechanism is based on a symplectic metachronsim in all examined species. The mucociliary transport in birds is fast and roughly follows the TLA, whereas the transport is slower and proceeds along a left-handed spiral in mammals. The longer wavelengths and the lower ratio between the metachronal wave speed and the mucociliary transport speed provide further evidence that the mucociliary clearance mechanism operates differently in birds than in mammals.

Inertial Flow of Viscoelastic Second-Grade Fluid in a Ciliated Channel under a Magnetic Field and Darcy’s Resistance

This paper proposes a mathematical analysis of the inertial flow of an MHD second-grade non-Newtonian fluid in a ciliated channel. The two-dimensional flow is modelled under the effect of inertial forces, magnetic field and Darcy’s resistance, which make the system of partial differential equations highly non-linear. To solve the complex system of partial differential equations, the Homotopy Perturbation Method (HPM) is preferred. The HPM solutions for the velocity profile, stream function and pressure gradient are obtained using the software MATHEMATICA. The significances of the Reynolds number (due to inertial forces), Hartmann number (due to magnetic field), porosity parameter (due to Darcy’s resistance) and fluid parameters (related to the second-grade fluid) on the pressure gradient, stream function and velocity profile are discussed in detail. The pertinent parameters show that the horizontal velocity decays in the presence of a magnetic field, whereas it rises under the effect of inertial forces, Darcy’s resistance and fluid viscosity in the centre of the channel. This research indicates that, for the ciliary flow of a second-grade fluid, a favourable pressure gradient (negative pressure gradient) in the horizontal direction increases when applying a magnetic field, whereas it decreases due to the porous medium. This mathematical model can be helpful to observe ciliary activity under magnetic resonance imaging, when ciliary activity is abnormal.