scholarly journals Rapid changes in mucociliary transport in the tracheal epithelium caused by unconditioned room air or nebulized hypertonic saline and mannitol are not determined by frequency of beating cilia

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Susyn Joan Kelly ◽  
Paul Martinsen ◽  
Stanislav Tatkov

Abstract Background Inspired air is heated and humidified in the nose before it reaches lower airways. This mechanism is bypassed during tracheostomy, directly exposing the airways to colder and drier air from the environment, known to negatively affect mucociliary transport; however, little is known about how quickly mucociliary transport deteriorates. This study determines the short-term effect of flowing room air and nebulized hypertonic saline and mannitol on mucociliary transport in the trachea. In an ovine perfused in vitro tracheal model (N = 9) the epithelium was exposed to 25 L/min of flow, heated to lamb body temperature (38 °C) and fully saturated with water vapor as the control, followed by either room air (22 °C and 50% relative humidity) or nebulized solutions of NaCl 7% and mannitol 20% up to 1 min for a short duration, until mucociliary transport had visually changed. Mucus transport velocity (MTV) and cilia beat frequency (CBF) were continuously measured with video-microscopy. Results Exposing the tracheal epithelium to air heated to body temperature and fully humidified had stable MTV 9.5 ± 1.1 mm/min and CBF 13.4 ± 0.6 Hz. When exposed to flow of room air, MTV slowed down to 0.1 ± 0.1 mm/min in 2.0 ± 0.4 s followed by a decrease in CBF to 6.7 ± 1.9 Hz, after 2.3 ± 0.8 s. Both MTV and CBF recovered to their initial state when heated and humidified air-flow was re-introduced. Exposing the tracheal epithelium to nebulized hypertonic saline and nebulized mannitol for 1 min increased MTV without a subsequent increase in CBF. Conclusions This study demonstrates mucociliary transport can deteriorate within seconds of exposing the tracheal epithelium to flowing room air and increase rapidly when exposed to nebulized hypertonic solutions. The reduction in MTV precedes slowing of CBF with room air and MTV increases without a subsequent increase in CBF during the nebulization. Their relationship is non-linear and a minimum CBF of approximately 6 Hz is required for MTV > 0, while MTV can reach 10.9 mm/min without CBF increasing. Clinically these findings indicate a potential rapid detrimental effect of breathing with non-humidified air via bypassed upper airways and the short-term effects of nebulized osmotic agents that increase MTV.

2021 ◽  
Author(s):  
Susyn Joan Kelly ◽  
Paul Martinsen ◽  
Stanislav Tatkov

Abstract BACKGROUND: Inspired air is heated and humidified in the nose before it reaches lower airways. This mechanism is bypassed during tracheostomy, directly exposing the airways to colder and drier air from the environment, known to negatively affect mucociliary transport; however, little is known about how quickly mucociliary transport deteriorates. This study determines the short-term effect of flowing room air and nebulized hypertonic saline and mannitol on mucociliary transport in the trachea. In an ovine perfused in vitro tracheal model (N=9) the epithelium was exposed to 25 L/min of flow, heated to lamb body temperature (38°C) and fully saturated with water vapor as the control, followed by either room air (22°C and 50% relative humidity) or nebulized solutions of NaCl 7% and mannitol 20% up to 1 min for a short duration, until mucociliary transport had visually changed. Mucus transport velocity (MTV) and cilia beat frequency (CBF) were continuously measured with video-microscopy. RESULTS: Exposing the tracheal epithelium to air heated to body temperature and fully humidified had stable MTV 9.5±1.1mm/min and CBF 13.4±0.6Hz. When exposed to flow of room air, MTV slowed down to 0.1±0.1mm/min in 2.0±0.4seconds followed by a decrease in CBF to 6.7±1.9Hz, after 2.3±0.8 second. Both MTV and CBF recovered to their initial state when heated and humidified air- flow was re-introduced. Exposing the tracheal epithelium to nebulized hypertonic saline and nebulized mannitol for 1 min increased MTV without a subsequent increase in CBF.CONCLUSIONS: This study demonstrates mucociliary transport can deteriorate within seconds of exposing the tracheal epithelium to flowing room air and increase rapidly when exposed to nebulized hypertonic solutions. The reduction in MTV precedes slowing of CBF with room air and MTV increases without a subsequent increase in CBF during the nebulization. Their relationship is non-linear and a minimum CBF of approximately 6Hz is required for MTV>0, while MTV can reach 10.9mm/min without CBF increasing. Clinically these findings indicate a potential rapid detrimental effect of breathing with non-humidified air via bypassed upper airways and the short-term effects of nebulized osmotic agents that increase MTV.


2020 ◽  
Author(s):  
Susyn Joan Kelly ◽  
Paul Martinsen ◽  
Stanislav Tatkov

Abstract BACKGROUND: Inspired air is heated and humidified in the nose before it reaches lower airways. This mechanism is bypassed during tracheostomy, directly exposing the lower airways to colder and drier air from the environment, which is known to have negative effects on mucociliary transport; however, little is known about how quickly mucociliary transport deteriorates. The purpose of this study was to determine the short-term effect of flowing room air on mucociliary transport in the trachea. In an ovine perfused in vitro tracheal model (N=7) the epithelium was exposed to 25 L/min of flow, heated to lamb body temperature (38 °C) and fully saturated with water vapor as the control, followed by room air (22 °C and 50% relative humidity) for a short duration, until mucociliary transport had visually stopped. Mucus transport velocity (MTV) and cilia beat frequency (CBF), as well as the area of the surface with beating cilia, were continuously measured with video-microscopy.RESULTS: Exposing the tracheal epithelium to air heated to body temperature and fully humidified resulted in stable MTV 9.5 ± 1.1 mm/min and CBF 13.4 ± 0.6 Hz. When exposed to the flow of room air, MTV slowed down to 0.1 ± 0.1 mm/min in 2.0 ± 0.4 seconds followed by a decrease in CBF to 6.7 ± 1.9 Hz, after 2.3 ± 0.8 second. Both MTV and CBF recovered to their initial state when heated and humidified air-flow was re-introduced. CONCLUSIONS: This study demonstrates mucociliary transport can deteriorate within seconds of exposing the tracheal epithelium to flowing room air. The reduction in MTV precedes slowing of CBF. Their relationship is non-linear and a minimum CBF of approximately 6 Hz is required for MTV > 0. Clinically these findings indicate a potential rapid detrimental effect of breathing with non-humidified air via bypassed upper airways.


Author(s):  
Susyn Joan Kelly ◽  
Vojta Brodecky ◽  
Elizabeth M. Skuza ◽  
Philip Berger ◽  
Stanislav Tatkov

Mucociliary transport in the respiratory epithelium depends on beating of cilia to move a mucus layer containing trapped inhaled particles towards the mouth. Little is known about the relationship between cilia beat frequency (CBF) and mucus transport velocity (MTV) in vivo under normal physiological conditions and when inspired air is dry or not fully humidified. This study was designed to use video-microscopy to simultaneously measure CBF and MTV in the tracheal epithelium through an implanted optical window in mechanically ventilated lambs. The inspired air in 6 animals was heated to body temperature and fully saturated with water for 4 hours as a baseline. In another series of experiments, 5 lambs were ventilated with air at different temperatures and humidities while the mucosal surface temperature was also monitored with infrared macro-imaging. In the baseline experiments during ventilation with fully humidified air at body temperature CBF remained fairly constant, mean 13.9±1.6Hz but MTV varied considerably between 0.1 and 26.1mm/min with mean 11.0±3.9mm/min, resulting in a maximum mucus displacement of 34.2µm/cilia beat. Fully humidified air at body temperature prevented fluctuations in the surface temperature during breathing indicating a thermodynamic balance in the airways. When lambs were ventilated with dryer air, the mucosal surface temperature and MTV dropped without a significant change in CBF. When inspired air was dry, mainly latent heat (92%) was transferred to air in the trachea, reducing the surface temperature by 5°C. Reduced humidity of the inspired air lowered the surface temperature and reduced MTV in the epithelium during ventilation.


2011 ◽  
Vol 46 (7) ◽  
pp. 666-671 ◽  
Author(s):  
Margaret Rosenfeld ◽  
Stephanie Davis ◽  
Lyndia Brumback ◽  
Stephen Daniel ◽  
Ron Rowbotham ◽  
...  

2002 ◽  
Vol 283 (2) ◽  
pp. L329-L335 ◽  
Author(s):  
Stephen T. Ballard ◽  
Laura Trout ◽  
Anil Mehta ◽  
Sarah K. Inglis

Because of its possible importance in cystic fibrosis (CF) pulmonary pathogenesis, the effect of anion and liquid secretion inhibitors on airway mucociliary transport was examined. When excised porcine tracheas were treated with ACh to induce gland liquid secretion, the rate of mucociliary transport was increased nearly threefold from 2.5 ± 0.5 to 6.8 ± 0.8 mm/min. Pretreatment with both bumetanide and dimethylamiloride (DMA), to respectively inhibit Cl− and HCO[Formula: see text]secretion, significantly reduced mucociliary transport in the presence of ACh by 92%. Pretreatment with the anion channel blocker 5-nitro-2-(3-phenylpropylamino)benzoic acid similarly reduced mucociliary transport in ACh-treated airways by 97%. These agents did not, however, reduce ciliary beat frequency. Luminal application of benzamil to block liquid absorption significantly attenuated the inhibitory effects of bumetanide and DMA on mucociliary transport. We conclude that anion and liquid secretion is essential for normal mucociliary transport in glandular airways. Because the CF transmembrane conductance regulator protein likely mediates Cl−, HCO[Formula: see text], and liquid secretion in normal glands, we speculate that impairment of gland liquid secretion significantly contributes to defective mucociliary transport in CF.


1998 ◽  
Vol 12 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Mark Jorissen

Mucociliary transport is one of the most important defense mechanisms of the airway. Mucociliary transport time or rate, as measured using the saccharin test or the radioisotope technique, respectively, is clinically the most relevant parameter, although subject to large intra- and interindividual variability. There is no correlation between mucociliary transport in vivo and ciliary beat frequency ex vivo. Preliminary evidence demonstrates that mucociliary transport correlates with ciliary structure and orientation as investigated with transmission and scanning electron microscopy. A correlation is presented between ciliary beat frequency and secondary ciliary abnormalities. This correlation can best be described according to the logistic sigmoid model (r = 0.69). Based on these functional data, an ultrastructural distinction is proposed among normal (less than 5%), light (5 to 15%), moderate (15 to 25%), and severe (more than 25%) secondary ciliary dyskinesia.


2005 ◽  
Vol 19 (4) ◽  
pp. 353-357 ◽  
Author(s):  
Mônica Aidar Menon-Miyake ◽  
Regiani Carvalho de Oliveira ◽  
Geraldo Lorenzi-Filho ◽  
Paulo Hilário Nascimento Saldiva ◽  
Ossamu Butugan

Background Luffa operculata is a medicinal plant used in homeopathic and alternative medicine. In the United States, it is sold in a purified spray form, whereas a homemade L. operculata dry fruit infusion (DFI) is commonly used in Latin America. The L. operculata DFI is applied intranasally, inducing profuse mucous secretion and relieving nasal symptoms. Nevertheless, this medication may cause irritation of the nasal mucosa, as well as epistaxis or anosmia. Given the growing popularity of alternative medicine, a decision was made to evaluate the effects of this substance on mucous membranes. Methods The effects of L. operculata DFI on mucociliary transport velocity, ciliary beat frequency, and transepithelial potential difference (PD) were evaluated in an isolated frog palate preparation. We tested 46 palates immediately before immersion and again at 5 and 20 minutes after immersion. Four groups (n = 10) were tested in frog Ringer: control; L. operculata DFI, 60 mg/L; 600 mg/L; and 1200 mg/L. An additional group was tested using L. operculata DFI prepared with water (600 mg/L of H2O, n = 6). Epithelial samples were harvested for ultrastructural study. Results In treated palates, mucociliary transport velocity and ciliary beat frequency decreased significantly (p < 0.001 and p < 0.008, respectively). There was a dose-dependent decrease in PD modulus (p < .007). Our PD findings indicated ion-fluid transport abnormalities, which were confirmed by transmission electron microscopy that showed enlargement of interepithelial spaces. Conclusion In this ex vivo model, the L. operculata DFI infusion promoted significant changes in the mucociliary function of the epithelium, suggesting that it is potentially noxious to human nasal mucosa.


PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247514
Author(s):  
Jean-François Le Galliard ◽  
David Rozen-Rechels ◽  
Anjélica Lecomte ◽  
Clémence Demay ◽  
Andréaz Dupoué ◽  
...  

Thermoregulation is critical for ectotherms as it allows them to maintain their body temperature close to an optimum for ecological performance. Thermoregulation includes a range of behaviors that aim at regulating body temperature within a range centered around the thermal preference. Thermal preference is typically measured in a thermal gradient in fully-hydrated and post-absorptive animals. Short-term effects of the hydric environment on thermal preferences in such set-ups have been rarely quantified in dry-skinned ectotherms, despite accumulating evidence that dehydration might trade-off with behavioral thermoregulation. Using experiments performed under controlled conditions in climatic chambers, we demonstrate that thermal preferences of a ground-dwelling, actively foraging lizard (Zootoca vivipara) are weakly decreased by a daily restriction in free-standing water availability (less than 0.5°C contrast). The influence of air humidity during the day on thermal preferences depends on time of the day and sex of the lizard, and is generally weaker than those of of free-standing water (less than 1°C contrast). This shows that short-term dehydration can influence, albeit weakly, thermal preferences under some circumstances in this species. Environmental humidity conditions are important methodological factors to consider in the analysis of thermal preferences.


2002 ◽  
Vol 112 (3) ◽  
pp. 570-573 ◽  
Author(s):  
Wilbert M. Boek ◽  
Kees Graamans ◽  
Hanny Natzijl ◽  
Peter P. van Rijk ◽  
Egbert H. Huizing

1997 ◽  
Vol 83 (4) ◽  
pp. 1348-1359 ◽  
Author(s):  
Scot L. Winters ◽  
Donovan B. Yeates

Winters, Scot L., and Donovan B. Yeates. Interaction between ion transporters and the mucociliary transport system in dog and baboon. J. Appl. Physiol. 83(4): 1348–1359, 1997.—To gain insight into the role of epithelial ion channels, pumps, and cotransporters in regulating airway water and mucociliary transport, we administered inhibitors of the Na+ channel (amiloride), 3Na-2K-adenosinetriphosphatase (acetylstrophanthidin), and Na-K-2Cl cotransporter (furosemide) to anesthetized dogs and/or baboons. Tracheal ciliary beat frequency was measured by using heterodyne laser light scattering. Tracheal mucus velocity (TMV) and bronchial mucociliary clearance (BMC) or lung mucociliary clearance were measured by using radioaerosols and nuclear imaging. Respiratory tract fluid output was collected by using a secretion-collecting endotracheal tube. In six dogs, amiloride aerosol [lung deposition, 96 ± 11 μg (means ± SE)] had minimal effect, whereas acetylstrophanthidin aerosol (lung deposition, 71 ± 9 μg) increased BMC, and furosemide (40 mg iv) markedly increased TMV. In five baboons, TMV increased after iv furosemide administration (2 mg/kg) as well as by aerosol (lung deposition, 20 ± 3 mg), coincident with increases in ciliary-mucus coupling from 11.5 ± 0.1 to 29.5 ± 0.4 and 46.5 ± 0.7 μm/beat, respectively. Furosemide also increased lung mucociliary clearance in baboons. In dogs, respiratory tract fluid output increased after intravenous furosemide from 2.2 ± 0.5 to 6.8 ± 1.7 mg/min. When combined with dry-air inhalation, furosemide failed to stimulate TMV and reversed the inhibition of BMC by dry air. Thus pharmacological manipulation of the Na-K-2Cl cotransporter and the 3Na-2K-adenosinetriphosphatase pump may provide increases of clinical relevance in airway hydration and mucociliary transport.


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