Mucociliary function

Infection of the trachea and bronchi causes hyperemic and edematous mucous membranes and an increase in bronchial secretions. Destruction of respiratory epithelium can range from mild to extensive and may affect bronchial mucociliary function. In addition, the increase in bronchial secretions, which can become thick and tenacious, further impairs mucociliary activity. Recurrent acute respiratory infections may be associated with increased airway hyperreactivity and possibly the pathogenesis of chronic obstructive lung disease. 

Nasal decongestant sprays such as phenylephrine and oxymetazoline that reduce inflammation by vasoconstriction are often used in sinusitis. Use should be limited to the recommended duration of the product to prevent rebound congestion. Oral decongestants may also aid in nasal or sinus patency. To reduce mucociliary function, irrigation of the nasal cavity with saline and steam inhalation may be used to increase mucosal moisture, and mucolytics (e.g., guaifenesin) maybe used to decrease the viscosity of nasal secretions. Antihistamines should not be used for acute bacterial sinusitis in view of their anticholinergic effects that can dry mucosa and disturb clearance of mucosal secretions. 

Mucociliary clearance Inhaled particles are cleared from the airways through trapping of the particles in mucus upon deposition and subsequent clearance of the mucus (with trapped particles) which is propelled by the coordinated beating of cilia towards the throat. This is termed the mucociliary escalator system. The mucociliary function is regulated by a variety of factors, such as bradykinin, histamine and cytokines [20-24],... 

Andersen et a/.," with a saccharine-particle method, found a weak positive association between tracheobronchial clearance and nasal clearance. A strong positive correlation would have indicated that information about the tracheobronchial clearance rate can be derived by studying clearance rates in the nose, which is more accessible. The saccharine method was shown to be a useful clinical tool for evaluating the status of the nasal mucociliary function in human subjects exposed to ambient pollutants or to controlled concentrations of specific pollutant gases or aerosols. 

Morimoto, K. Uehara, Y. Iwanaga, K. Kakemi, M. Ohashi, Y. Tanaka, A. Nakai, Y. Influence of absorption enhancers (bile salts) and the preservative (benzalkonium chloride) on mucociliary function and permeation barrier function in rabbit tracheas. Eur. J. Pharm. Sci. 1998, 6 (3), 225-230. 

These structural features allow the Ipratropium molecule to attain a relatively selective bronchodilator effect on the cholinergi-cally innervated airways. By the inhalation route of application, this poorly absorbable quaternary ammonium derivative becomes selective to primarily affect the airway smooth muscle. Another advantage of ipratropium over atropine is that, in contract to the latter, it does not suppress mucociliary function. 

The rate of removal of mucus from the airways is determined by such factors as mucus viscosity, the amount of mucus produced, and the degree of ciliary activity. These processes may be influenced by a variety of diseases, including asthma, cystic fibrosis, and chronic bronchitis [82,83], In patients suffering from cystic fibrosis or chronic bronchitis, mucus hypersecretion is evident and mucociliary function is impaired. The failure to clear mucus from the airways leads to airway obstruction and to chronic colonization of the airways with bacterial organisms (which leads to lung infections and airway inflammation and damage). In asthmatic subjects, airway mucus is more viscous and ciliary transport mechanisms are inhibited [82,83]. In these diseases, the therapeutic objective is to improve mucus clearance from the airways. For example, aerosols of water or saline (especially hypertonic saline) promote clearance of mucus by... 

Morgan KT, Gross EA, Patterson DL. 1986a. Distribution, progression, and recovery of acute formaldehyde-induced inhibition of nasal mucociliary function of F-344 rats. Toxicol Appl Pharmacol 86 448-456. 

ETS has been described to act on the airway mucosa in several different ways. The constituents of ETS have been demonstrated to have a negative effect on mucociliary function [263(111)]. It has been postulated [264(111)] but despite considerable efforts never proven, that tobacco proteins present in smoke, can, like conventional allergens, cause IgE sensitisation. 

The inhalational anesthetics halothane, isoflurane, and enflu-rane all have been reported to have a positive effect in children and adults with severe asthma that is unresponsive to standard medical therapy. The proposed mechanisms for inhalational anesthetics include direct action on bronchial smooth muscle, inhibition of airway reflexes, attenuation of histamine-induced bronchospasm, and interaction with /32-adrenergic receptors. Well-controlled trials with these agents have not been completed. Potential adverse effects include myocardial depression, vasodilation, arrhythmias, and depression of mucociliary function. In addition, the practical problem of delivery and scavenging these agents in the intensive care environment as opposed to the operating room is a concern. The use of volatile anesthetics cannot be recommended based on insufficient evidence of efficacy. 

Surgical incision Penetrating trauma Vascular access devices Impaired mucociliary function of the lungs Smoking... 

Normal physiological functioning of the sinuses depends on ostial patency, mucociliary function, and the quantity and quality of secretions. Retention of sinus secretions may result if ostial diameter is compromised if cilia are damaged, impairing mucociliary clearance of secretions or if increased viscosity or volume of secretions exceeds the clearing capacity of the sinus mucociliary drainage system. 

The goal in treatment of sinusitis is eradication of infection with clearance of the infected material from the sinuses. While the use of an appropriate antibiotic is necessary, the use of ancillary therapy is also of utmost importance. Steam and nasal saline, decongestants, topical corticosteroids, and mucoevacuants are given in an attempt to reduce nasal obstruction, increase sinus ostia size, promote improved mucociliary function, decrease mucosal inflammation, and thin secretions. In selected patients who fail to respond to aggressive medical therapy, functional endoscopic surgery can often provide relief. In patients with poorly controlled asthma, treatment of underlying sinusitis has been shown to dramatically improve the asthmatic state. 

Pathophysiology. The etiology of CB is not known. One suspects that there is an individual susceptibility which may predispose to the development of CB which is likely dependent on inherited and acquired host defense capability. A classification of host defense factors would include cellular, immune, non-immune humoral and mucociliary functions (7), Acquired host defense problems may be related to the patient s concomitant disease(s) such as CBA, tuberculosis, sickle cell disease, etc. 

Nasal preparations can be formulated as liquid, semisolid or solid preparations and can contain one or more active substances. Whether intended for local or systemic action, the mucociliary function of the nose should be disturbed as httle as possible by the preparation However, it is well known that active substances as weU as excipients may have a negative influence on the mucociliary clearance, in other words may be cdiotoxic. In the formulation of nasal preparations one should take into consideration the possible damage to the cilia in relation to the indication and the period of use. 

New technology opens up completely new possibilities to design 3D structures for medical applications. The hexagonal braiding technique developed by Schreiber et al. (2009) allows various shapes such as bifurcations or stent into the stent to be produced. Such braided multilayer structures create mechanically separated layers on the outside and an inner structure that facilitates, for example, a functional respiratory epithelium to be established and make it possible to maintain the mucociliary function of the stented area in treatment of lung cancer (PulmoStent, 2014). 

However, the ideal stent has not yet been developed. Such a stent would combine ease of insertion, potential removal, resistance to migration and tumor ingrowth, no or minimal induction of granulation tissue formation, and preservation of mucociliary function. 

Wolff RK. Mucociliary function. In Parent RP, ed. Comparative Biology of the Normal Lung. Boca Raton, FL CRC Press, 1992 659-680. 

Foster WM, Langenback EG, Bergofsky EH. Lung mucociliary function in man interdependence of bronchial and tracheal mucus transport velocities with lung clearance in bronchial asthma and healthy subjects. Ann Occup Hyg (Inhaled Particles V) 1982 26 227-244. 

IV. Stimulation of Secretion and Modulation of Mucociliary Function by Particles... 

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