Mucociliary transport and its assessment: a review

High-speed digital imaging method for ciliary beat frequency measurement

The aim of this study was to develop a high-speed digital imaging system and related software for ciliary beat frequency (CFB) analysis in order to establish an automated and reliable method that is observer independent and faster compared to the conventional computerized microscope photometry method. Using primary human nasal epithelial cell cultures, the CBF was recorded with a computerized microscope photometry system and a high-speed digital imaging system. To obtain a wide range of frequencies, glycocholate (0.5%) and chlorocresol (0.005%) were used as ciliostimulatory and cilio-inhibitory reference compounds, respectively. The mean values in hertz (+/- s.d.) obtained with the photometry and high-speed digital imaging systems were: controls 8.2 +/- 0.9 and 7.9 +/- 1.1; chlorocresol 5.0 +/- 0.9 and 5.1 +/- 1.1; glycocholate 9.8 +/- 1.0 and 9.7 +/- 0.8. A similar increase (by 20 and 24%) and decrease (by 38 and 35%) in CBF was determined by the two methods after glycocholate and chlorocresol treatment, respectively. The mean difference between the photometry and high-speed digital imaging methods was 0.2 +/- 0.6 Hz, and the Bland-Altman limits of agreement were from -1.0 to +1.4 Hz, suggesting that the results obtained by these two methods could be used interchangeably. These results show the reliability of the high-speed digital imaging system and the software developed for in-vitro CBF measurements. The advantages of the system include: (i) fast data acquisition and calculation, (ii) whole field automated CBF analysis and (iii) reduction in selection bias.

Physiological and Subjective Responses to Low Relative Humidity in Young and Elderly Men

In order to compare the physiological and the subjective responses to low relative humidity of elderly and young men, we measured saccharin clearance time (SCT), frequency of blinking, hydration state of the skin, transepidermal water loss (TEWL), sebum level recovery and skin temperatures as physiological responses. We asked subjects to evaluate thermal, dryness and comfort sensations as subjective responses using a rating scale. Eight non-smoking healthy male students (21.7+/-0.8 yr) and eight non-smoking healthy elderly men (71.1+/-4.1 yr) were selected. The pre-room conditions were maintained at an air temperature (Ta) of 25 degrees C and a relative humidity (RH) of 50%. The test-room conditions were adjusted to provide 25 degrees C Ta and RH levels of 10%, 30% and 50%. RH had no effect on the activity of the sebaceous gland or change of mean skin temperature. SCT of the elderly group under 10% RH was significantly longer than that of the young group. In particular, considering the SCT change, the nasal mucous membrane seems to be affected more in the elderly than in the young in low RH. Under 30% RH, the eyes and skin become dry, and under 10% RH the nasal mucous membrane becomes dry as well as the eyes and skin. These findings suggested that to avoid dryness of the eyes and skin, it is necessary to maintain greater than 30% RH, and to avoid dryness of the nasal mucous membrane, it is necessary to maintain greater than 10% RH. On the thermal sensation of the legs, at the lower humidity level, the elderly group felt cooler than the young group. On the dry sensation of the eyes and throat, the young group felt drier than the elderly group at the lower humidity levels. From the above results, the elderly group had difficulty in feeling dryness in the nasal mucous membrane despite being easily affected by low humidity. On the other hand, the young group felt the change of humidity sensitively despite not being severely affected by low humidity. Ocular mucosa and physiology of skin by dryness showed no difference by age. In the effect of longer exposure (180 min.) to low RH, only TEWL showed a slight decrease after 120 minutes in 30% RH, and all the measured results showed no noticeable differences compared with the result at 120 minutes.

Physiological and Subjective Responses to Low Relative Humidity

In order to investigate the influence of low relative humidity, we measured saccharin clearance time (SCT), frequency of blinking, heart rate (HR), blood pressure, hydration state of skin, transepidermal water loss (TEWL), recovery sebum level and skin temperature as physiological responses. We asked subjects to judge thermal, dryness and comfort sensations as subjective responses using a rating scale. Sixteen non-smoking healthy male students were selected. The pre-room conditions were maintained at an air temperature (Ta) of 25 degrees C and a relative humidity (RH) of 50%. The test room conditions were adjusted to provide a Ta of 25 degrees C and RH levels of 10%, 30% and 50%.RH had no effect on the activity of the sebaceous gland and on cardiovascular reactions like blood pressure and HR. However, it was obvious that low RH affects SCT, the dryness of the ocular mucosa and the stratum corneum of the skin and causes a decrease in mean skin temperature. Under 30% RH, the eyes and skin become dry, and under 10% RH the nasal mucous membrane becomes dry as well as the eyes and skin, and the mean skin temperature decreases. These findings suggested that to avoid dryness of the eyes and skin, it is necessary to maintain an RH greater than 30%, and to avoid dryness of the nasal mucous membrane, it is necessary to maintain an RH greater than 10%. Subjects felt cold immediately after a change in RH while they had only a slight perception of dryness at the change of humidity.

The effect of injection immunotherapy on mucociliary clearance in allergic patients

OBJECTIVE

To assess the effect of injection immunotherapy on mucociliary clearance in allergic patients with the use of the saccharin test.

METHODS

In this prospective cohort study, mucociliary clearance in 42 allergic patients treated with injection immunotherapy was determined with the saccharin test. Of these patients, 23 were retested 1 year later to assess changes in mucociliary clearance times. Mean results for historical controls were determined in a review and meta-analysis of the existing literature.

RESULTS

Saccharin clearance times (SCTs) were initially prolonged in allergic patients who received injection immunotherapy when compared to historical controls (one-sided P value < 0.05). However, after 1 year of immunotherapy, there was a significant reduction in SCTs in our patient population. This finding was independent of other evaluated patient characteristics, with the exception of nasal steroid use, which was also significantly associated with a decrease in SCT.

CONCLUSIONS

After 1 year of injection immunotherapy, there was a significant reduction in mean SCT in our patient population. Of the other factors studied, only nasal steroid was associated with decreased mucociliary clearance times. To our knowledge, this is the first report in the literature documenting the beneficial effect of injection immunotherapy on mucociliary clearance as measured by saccharin clearance times. Nevertheless, further research is warranted, given the confounding effect of nasal steroid use.

Effect of topical nasal steroid sprays on nasal mucosa and ciliary function

PURPOSE OF REVIEW

This review was conducted to examine current evidence focusing on the effect of nasal steroid sprays on nasal ciliary function.

RECENT FINDINGS

Review of current literature suggests that long term effects of topical corticosteroid nasal sprays are safe and fail to cause damage to local nasal structure and function.

SUMMARY

The use of corticosteroid nasal sprays for the treatment of allergic rhinitis is widely accepted. Popularity of this class of medications is based on a well-established combination of efficacy, tolerability, and safety. Although current literature suggests that the use of intranasal steroids is indeed safe, increasing indications for prolonged administration continue to fuel debate regarding the long-term effect on local nasal structure and function. The purpose of this article is to review current literature addressing the effects of the components of local intranasal steroid sprays on the structure and function of the nasal mucosa.

Mucociliary clearance after external dacryocystorhinostomy

We investigated the nasal mucociliary clearance time in 17 patients who underwent a primary unilateral external dacryocystorhinostomy operation. Mucociliary clearance function in both nasal cavities was assessed with the saccharin test. The results were compared with each other using paired samples t-test. We found significantly worse mucociliary clearance time on the operated side (mean: 6.3 min) than on the non-operated side (mean: 5.5 min) (P = 0.004). External dacryocystorhinostomy negatively affected the mucociliary clearance function in this study.

Effects of Preservatives in Nasal Formulations on the Mucosal Integrity: An Electron Microscopic Study

The preservatives benzalkonium chloride (BZC) and potassium sorbate (PS) are widely used in the formulation of nasal drops and cosmetics. Recently, a number of side effects that resulted from mucosal irritation caused by BZC and PS have been reported. Therefore, this study was performed to investigate the possible clinical and histological alterations induced by in vivo administration of these preservatives to the nasal mucosa of rats. 0.01% BZC and 0.12% PS were administered to the nostrils of male rats for 1 or 4 weeks. Clinical symptoms were recorded during the treatment, and light and electron microscopic examinations were carried out on samples taken from one third central and lower regions of the noses at the end of the treatment periods. Symptomatic changes such as sneezing and nasal rubbing were observed in almost all groups, starting from the 6th day of administration. Light and electron microscopy showed histological changes and nasal lesions induced by the preservatives. The symptomatic and histological changes were more pronounced with prolonged duration of administration. Therefore, it has been concluded that in vivo administration of the preservatives BZC and PS may be irritant to the respiratory epithelium of rats.

Immunisation schedules for non-replicating nasal vaccines can be made simple by allowing time for development of immunological memory

Mice immunised intranasally with multiple doses of outer membrane vesicles (OMVs) from group B meningococci developed antibody responses that depended on the interval between doses. High levels of antibodies in saliva and extracts of faeces were induced within 4 weeks after an OMV vaccine had been given at weekly intervals, whereas the antibody responses in these samples were negligible when given four times at 1-day or 1-h intervals, or as one large dose. Only modest responses were obtained in serum after 4 weeks, however, whether the vaccine had been given repeatedly at any schedule, including the 1-week interval, or as one dose. On the other hand, two large doses given 8 weeks apart induced booster antibody responses in both serum and secretions that matched the responses from a second series of the four smaller doses. Intranasal immunisations may thus stimulate immunological memory more rapidly in secretions than in serum. In order to secure adequate systemic responses by a minimum of doses, nasal vaccines should therefore be given at intervals longer than 4 weeks, in harmony with the intervals recommended for injectable vaccines.

Nasal mucociliary transport: new evidence for a key role of ciliary beat frequency

OBJECTIVES/HYPOTHESIS

Mucociliary transport is an important defense mechanism of the respiratory tract. Nonetheless, the factors determining mucociliary transport are only partially understood. Ciliary beat frequency is assumed to be one of the main parameters, although the experimental evidence remains inconclusive.

STUDY DESIGN

Comparing influences on mucociliary transport to influences on ciliary beat frequency.

METHODS

The present study measures the effects on mucociliary transport of two ciliary beat frequency-inhibiting compounds (0.1% xylometazoline and 0.9% NaCl) and a ciliary beat frequency enhancer (0.1% salbutamol). The measurements were performed by a technetium-99m nebulizing scintigraphic method. The experiments were carried out in 15 healthy young volunteers.

RESULTS

The 0.1% xylometazoline appeared to slow ciliary transport, although the decrease was not significant (P = .44). The 0.9% NaCl did reduce mucociliary transport significantly (P = .033). The 0.1% salbutamol resulted in a highly significant increase of mucociliary transport (P = .009). Xylometazoline brings about drastic changes in the nasal cavity, both anatomically and physiologically. Any comparison of mucociliary transport before and after using this vasoconstrictive agent must take this effect into account.

CONCLUSIONS

The present study demonstrates a significant similarity in the effects of NaCl and salbutamol on ciliary beat frequency in vitro and on mucociliary transport in vivo. The evidence from our experiments suggests that ciliary beat frequency is a determining factor in the mucociliary transport rate in the nose.

The nose and paranasal sinuses physiology and anatomy

The paranasal sinuses and nose are much more than two cavities behind a projection on the centre of the face. They humidify, filter, warm, and sense what we breathe. The anatomy and physiology interact forming a dynamic system. The anatomy, airflow, nasal resistance, its turbulence, the nasal cycle - a process by which the turbinates or cushions lining the nose alternatively swell and congest from side to side, can all potentially influence the nasal delivery of drugs. Along with these factors mucus rheology and mucociliary clearance influence the removal of substances delivered to the nose. The health of the nose and its immunological response to what is inhaled, be it pollutants, allergens, drugs or vaccines, all need to be considered. It is a fascinating sensor for the body, not only detecting the potentially harmful substances such as smoke, but its psychosexual aspects have far reaching implications and the olfactory pathway has potential as a pathway for the delivery of drugs.

Benzalkonium chloride as a preservative in nasal solutions: re-examining the data

Recent studies have suggested that benzalkonium chloride (BKC), an antimicrobial agent used as a preservative in nasal sprays, lacks deleterious effects on the nasal ciliated epithelium. Other data, including recent in vivo findings, suggest that BKC may, in fact, produce adverse clinical effects on human nasal tissue, including the aggravation of rhinitis medicamentosa. Toxic effects have also been reported. In light of the discrepancy between negative results and studies suggesting no safety concerns, we consider the possibility of problems in the design and methodology of some of the studies and in the interpretation of results. Clearly, further research is warranted to clarify the significance of conflicting findings. In the meantime, without conclusive data regarding BKC and the possibility of harmful effects, the use of nasal formulations without BKC might be a reasonable alternative.

Investigation for immunodeficiency in patients with recurrent ENT infections

Patients suffering with primary immunodeficiency frequently present to ear, nose, and throat (ENT) clinics, but the diagnosis is rarely made at this time. Early diagnosis of these patients would help to prevent morbidity and even mortality. Normal results from a simple panel of blood tests will exclude the commonest immune deficiencies. An abnormal result from these tests, or a strong suspicion despite normal initial testing, should prompt discussion with an immunologist.

Nasal mucociliary transport in pregnancy

Using the saccharin method, we performed tests of mucociliary function four times during pregnancy and once one month after delivery in 27 women. As the transport distance for saccharin varied from 37 to 65 mm, we used the transport speed for evaluation. Pregnancy rhinitis affects at least 20% of pregnancies. The mucociliary transport speed was higher in the group of women with pregnancy rhinitis, and was reduced during pregnancy in the group of women without that condition. We found no significant correlation between mucociliary transport speed and objectively registered nasal peak expiratory flow index. The pathophysiology of pregnancy rhinitis is not known, but is possibly multifactorial. The changes occurring in the nasal mucociliary transport system during normal pregnancy and in pregnancy rhinitis need further studies.

Is the use of benzalkonium chloride as a preservative for nasal formulations a safety concern? A cautionary note based on compromised mucociliary transport

BACKGROUND

Topical nasal solution and suspension delivery systems are available for short- and long-acting vasoconstrictors, ipratropium, cromolyn, azelastine, and glucocorticosteroids. The use of intranasal glucocorticosteroids has increased substantially because the efficacy of these agents has been well established for the treatment of perennial and seasonal allergic rhinitis. Adverse local effects of burning, irritation, and dryness are occasionally associated with glucocorticosteroid nasal preparations. Benzalkonium chloride (BKC) is a quaternary ammonium antimicrobial agent included in some nasal solutions (including glucocorticosteroids) to prevent the growth of bacteria. Some reports suggest that BKC in nasal sprays may cause adverse effects, including reduced mucociliary transport, rhinitis medicamentosa, and neutrophil dysfunction.

OBJECTIVE

This article summarizes recent literature about possible adverse biologic effects associated with BKC as a nasal spray preservative by examining its effects on the following properties of mucociliary transport: ciliary motion, ciliary form, ciliary beat frequency, electron microscopy, and particle movement/saccharin clearance tests.

CONCLUSION

Both animal and human in vitro data suggest that BKC promotes ciliostasis and reduction in mucociliary transport that may be partially masked by absorption and dilution effects occurring in respiratory mucus. These possible confounding factors may account for several disparate human in vivo results. The use of BKC-free glucocorticosteroid formulations should be considered, particularly in patients who complain of nasal burning, dryness, or irritation.