Measurement of mucociliary function of the eustachian tube

Changes in Eustachian Tube Mucosa in Mice After Short-Term Tobacco and E-cigarette Smoke Exposure

OBJECTIVES

To evaluate histologic changes in middle ear and eustachian tube (ET) mucosa of mice after exposure to tobacco or electronic cigarette (e-cigarette) smoke. To determine whether there were any mitigating effects of middle ear application of anti-IL-13 or the epidermal growth factor receptor antagonist AG1478 on noted changes within ET mucosa.

STUDY DESIGN

Controlled animal study.

METHODS

Fifty BALB/cJ mice were randomly assigned to one of five groups: A control group with no smoke exposure, two groups exposed to tobacco smoke, and two groups exposed to e-cigarette vapor. Within the exposed groups after 4 weeks of exposure, one ear was infiltrated with a saline hydrogel and the other ear with hydrogel of either Anti-IL-13 or AG1478. After four more weeks of exposure, the animals were euthanized and the ETs were evaluated for mucosal changes.

RESULTS

Compared to control animals with no smoke exposure, there were significant decreases in the numbers of goblet cells within the ET mucosa of mice exposed to tobacco smoke and e-cigarette vapor. No significant differences in cilia, mucin, or squamous metaplasia were noted. Neither anti-IL-13 nor AG178 significantly altered goblet cell count in the ET mucosa of mice exposed to tobacco smoke; however, both agents significantly increased goblet cells within the ET mucosa of mice exposed to e-cigarette vapor.

CONCLUSION

Short-term tobacco smoke and e-cigarette vapor significantly decrease goblet cell count in mouse ET mucosa. Middle ear application of both anti-IL-13 and AG1478 resulted in an increase in goblet cell count among mice exposed to e-cigarette vapor, but not to tobacco smoke.

LEVEL OF EVIDENCE

NA Laryngoscope, 2021.

Quantitation of Tubotympanal Mucociliary Clearance in Otitis Media with Effusion

In an attempt to analyze the tubotympanal mucociliary function in otitis media with effusion (OME), human serum albumin labeled with technetium 99m was instilled into 36 ears with effusion and 16 without. The clearance function of the tubotympanum was measured quantitatively. The viscoelasticity of the effusions was measured and was compared with the clearance rate. The clearance rate was significantly lower in ears with effusion than in those without. A significant negative correlation was observed between clearance rate and dynamic viscosity at dynamic viscosities above 2 poise. It is concluded that ears with effusion have significantly lower mucociliary clearance than those without, and that the viscosity of the effusions plays an important role in the mucociliary dysfunction in OME.

Mucociliary function of the eustachian tube in the eustachian tube dysfunction

BACKGROUND

Most of the tests to evaluate the eustachian tube (ET) function are focused on the ventilation function of the ET.

AIM

Here we evaluate mucociliary function of the ET in patients with ET dysfunction.

MATERIALS AND METHODS

Ten patients with ET dysfunction were enrolled into the study. Six patients had chronic tympanic membrane retraction and four patients had chronic middle ear effusion (MEE). All patients had intact tympanic membranes. Tympanometry and clinical examinations were done to all patients. Mucociliary function was evaluated with technetium labeled albumin and blue dye. Tympanometry and clinical examinations were done to six patients with chronic tympanic membrane retraction and four patients with chronic middle ear effusion (MEE). Mucociliary function of the ET was evaluated with technetium labeled albumin and blue dye placed into middle ear through an intact tympanic membrane and followed from nasopharynx ET orifice (blue dye) and with gamma camera (technetium).

RESULTS

Blue dye was observed in tubal orifice in six (6 of 10) patients during 30 min observation. Five of those patients (5 of 6) had tympanic membrane retraction and one patient (1 of 6) had MEE. Tracer activity decreased from middle ear in six (6 of 10) patients. Four of those patients had tympanic membrane retraction and two had MEE.

CONCLUSION

Mucociliary function of the ET seems to be better in patients with tympanic membrane retraction than patients with middle ear effusion.

SIGNIFICANCE

Mucociliary function of the ET is an important function for middle ear aeration, blue dye test is easily available to be used also in clinical practice.

Innovative Use of Tympanometry and Scintigraphy in Preoperative Assessment of the Patients with Chronic Otitis Media

Normal middle ear volume indicates the well ventilated middle ear and subsequently the normal function of the Eustachian tube. We carried out preoperative assessment of the middle ear volume by tympanometry and scintigraphic evaluation of Eustachian tube patency in patients with unilateral otitis media. We correlated the middle ear volume and Eustachian tube patency in these patients. Prospective. A total of 58 patients with unilateral otitis media were studied. All patients underwent Eustachian tube scintigraphy. We categorized the patients as Group A with patent Eustachian tube and Group B with blocked Eustachian tube (ET). We assessed the equivalent middle ear volume (VeqME) in all patients and correlated it with ET patency. We also correlated the degree of hearing loss and intraoperative middle ear pathology in two groups. There is strong linear correlation between the ET patency and VeqME of the patients. Degree of hearing loss and the middle ear pathology is also found to be severe in patients with blocked ET and low VeqME. Preoperative assessment of patients with chronic otitis media should include the objective evaluation of middle ear volume and ET patency, as it is the reliable predictor of middle ear pathology.

Analysis of Otologic Features of Patients With Primary Ciliary Dyskinesia

OBJECTIVE

To evaluate otologic features of primary ciliary dyskinesia (PCD), especially eardrum features, audiometric findings, and clinical course.

STUDY DESIGN

Retrospective patient review.

SETTING

Tertiary referral center.

PATIENTS

Fifteen patients (mean age, 16.9 years [range, 1-32 yr]; 8 males and 7 females) diagnosed with PCD at our university hospital in the last 12 years.

INTERVENTION

Diagnostic.

MAIN OUTCOME MEASURES

Electron microscopy of nasal cilia, gene mutation analysis, endoscopy of 30 eardrums, pure-tone audiometry, and tympanometry.

RESULTS

All 15 patients showed ciliary ultrastructural abnormalities on electron microscopy and/or biallelic mutations in genes associated with ciliary function or structure. All 30 eardrums examined showed certain abnormalities. Fourteen patients had otitis media with effusion or its sequelae. The remaining patient had chronic otitis media. Pure-tone audiometry revealed the mean air conduction thresholds to be 25.0 and 26.4 dB in the right and left ears, respectively. In the ears with better hearing and worse hearing, the mean air conduction thresholds were 22.3 and 29.0 dB respectively.

CONCLUSION

Otologic disease among patients with PCD essentially comprised otitis media with effusion, and the patients' eardrums showed a variety of findings. Knowledge of these otologic features may lead to the early detection of PCD.

The development of the mammalian outer and middle ear

The mammalian ear is a complex structure divided into three main parts: the outer; middle; and inner ear. These parts are formed from all three germ layers and neural crest cells, which have to integrate successfully in order to form a fully functioning organ of hearing. Any defect in development of the outer and middle ear leads to conductive hearing loss, while defects in the inner ear can lead to sensorineural hearing loss. This review focuses on the development of the parts of the ear involved with sound transduction into the inner ear, and the parts largely ignored in the world of hearing research: the outer and middle ear. The published data on the embryonic origin, signalling, genetic control, development and timing of the mammalian middle and outer ear are reviewed here along with new data showing the Eustachian tube cartilage is of dual embryonic origin. The embryonic origin of some of these structures has only recently been uncovered (Science, 339, 2013, 1453; Development, 140, 2013, 4386), while the molecular mechanisms controlling the growth, structure and integration of many outer and middle ear components are hardly known. The genetic analysis of outer and middle ear development is rather limited, with a small number of genes often affecting either more than one part of the ear or having only very small effects on development. This review therefore highlights the necessity for further research into the development of outer and middle ear structures, which will be important for the understanding and treatment of conductive hearing loss.

Development and Integration of the Ear

The perception of our environment via sensory organs plays a crucial role in survival and evolution. Hearing, one of our most developed senses, depends on the proper function of the auditory system and plays a key role in social communication, integration, and learning ability. The ear is a composite structure, comprised of the external, middle, and inner ear. During development, the ear is formed from the integration of a number of tissues of different embryonic origin, which initiate in distinct areas of the embryo at different time points. Functional connections between the components of the hearing apparatus have to be established and maintained during development and adulthood to allow proper sound submission from the outer to the middle and inner ear. This highly organized and intimate connectivity depends on intricate spatiotemporal signaling between the various tissues that give rise to the structures of the ear. Any alterations in this chain of events can lead to the loss of integration, which can subsequently lead to conductive hearing loss, in case of outer and middle ear defects or sensorineural hearing loss, if inner ear structures are defective. This chapter aims to review the current knowledge concerning the development of the three ear compartments as well as mechanisms and signaling pathways that have been implicated in the coordination and integration process of the ear.

ENT manifestations in patients with primary ciliary dyskinesia: prevalence and significance of otorhinolaryngologic co-morbidities

Primary ciliary dyskinesia (PCD) is a rare inherited disease with a prevalence of about 1:20,000. The underlying pathogenesis is disrupted ciliary function, which results in delayed mucus transportation leading to chronic inflammation, mainly in the upper and lower respiratory tract. Although the pathogenesis of the disease and its clinical presentation is somewhat understood, data regarding the prevalence of accompanying symptoms is limited, especially in the field of otorhinolaryngology. A total of 44 patients diagnosed with PCD answered a questionnaire regarding the diagnosis and clinical presentation of the disease, their medical history and clinical manifestations, and medical treatment in the field of otorhinolaryngology. The majority of participants (70%) had seen a physician more than 50 times before the diagnosis was made at an average age of 10.9 ± 14.4 years. As much as 59% of all patients had recurring problems at the paranasal sinuses and 69% of these patients needed corresponding surgical intervention. Even more patients (81%) suffered from recurring otitis media and, as a result, 78% of these patients underwent paracentesis with temporary tympanostomy tubes at least once at an average age of 9.5 ± 13.0 years. Otorhinolaryngologic symptoms, especially chronic otitis media and chronic rhinosinusitis, are frequently associated with PCD. Surgical intervention to treat these symptoms is common. The awareness of this disease should be raised, especially among ENT physicians, and surgical intervention should be indicated carefully.

Assessment of eustachian tube function in tympanoplasty

Objective: A clinically useful test for eustachian tube function (ETF) is still lacking. Here we plan to evaluate the mucociliary function of the ET by saccharin and methylene blue test, and compare the outcome of surgery with normal and abnormal ET functions.

Study Design: Case series with planned data collection.

Setting: Department of Otolaryngology–Head and Neck Surgery, Kasturba Medical College, Mangalore (Manipal University), a tertiary care center in South India.

Subjects and Methods: This study comprised 86 patients diagnosed with mucosal chronic otitis media in quiescent/inactive stage. All were subjected to a detailed clinical examination and investigations. Preoperative evaluation of ETF was compared with postoperative outcome of surgery, and the results were analyzed.

Results: The saccharin test and methylene blue dye test had a good correlation in evaluating ETF. The mean value for saccharin perception time and the clearance time for methylene blue were 17.5 and 8.1 minutes, respectively. ETF was best in anterior, worst among posterior, and intermediate in subtotal perforations. Type 1 tympanoplasty was successful in 94 percent with normal ETF and in 68 percent with partial dysfunction.

Conclusion: The saccharin test is a simple, cost-effective, and valuable diagnostic tool to assess the mucociliary function of the ET. The outcome of middle ear surgery would be a success in normal ETF, whereas in partial dysfunction the outcome need not necessarily be a failure.

Factors associated with the presence of drug-resistant bacteria and recurrent acute otitis media in children--a study in a private clinic

CONCLUSIONS

The proportion of drug-resistant bacteria was lower than previous reports. In children with acute otitis media (AOM), lower age, presence of multiple bacteria, and otitis media with effusion (OME) represented significant factors for recurrent AOM and the presence of drug-resistant bacteria.

OBJECTIVE

Recently, the proportion of drug-resistant bacteria has been increasing in children with AOM. We studied the proportion of drug-resistant bacteria and background factors for detection of drug-resistant bacteria and recurrent AOM in a private clinic.

SUBJECTS AND METHODS

Subjects comprised 170 patients <12 years old with AOM. Middle ear fluid was collected and pathogenic bacteria were identified. The following factors were considered: age, sex, use of antibiotics in the past 1 month, past history of recurrent AOM, presence of OME, and multiple bacteria of the three main strains (Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis).

RESULTS

A total of 169 strains were detected in 77% of children with AOM. Drug-resistant bacteria comprised 44 of the 169 strains (26%). Lower age (p=0.001) and presence of multiple bacteria (p<0.001) represented significant factors for the presence of drug-resistant bacteria. OME was a significant factor for recurrent AOM (p<0.001).

Mechanism and Rate of Middle Ear Fluid Absorption

Several mechanisms have been suggested to explain the clearance of fluids from the middle ear. These include a pumping action through the eustachian tube, mucociliary beating through the tube, outflow of water to the blood due to osmotic gradients and an active Na(+) transport driving water absorption. In order to assess these mechanisms, the middle ear cavity of paralyzed, ventilated (eustachian tube occluded) guinea pigs was filled with fluids varying in osmotic pressure (hypotonic, isotonic, hypertonic) to which a vertical tube was attached. The change in height of fluid in the tube was taken as a measure of changes in middle ear fluid volume. A greater fluid volume reduction was seen with the hypotonic (1/5 saline) solution. A small volume increase was observed with the hypertonic solution. These results provide evidence that in these experimental conditions, water absorption due to osmotic gradients can contribute to middle ear fluid clearance.

Mechanisms responsible for postnatal middle ear amniotic fluid clearance

Neonatal guinea pigs show signs of a temporary conductive hearing loss during the first few days after birth. It has been suggested that this is due mainly to the presence of amniotic fluid in the middle ear (ME) cavity at birth and its subsequent clearance. This study was designed to try to identify the mechanisms responsible for the amniotic fluid clearance from the ME after birth by means of several experiments in guinea pigs. The osmolarity of the blood, amniotic fluid and the fluid in the ME cavity of guinea pig fetuses was measured. Serum and normal saline were introduced into the ME of older animals and fluid clearance was monitored short- and long-term by microscopic observation, tympanometry and estimation of residual fluid. Following instillation of 1/5 normal saline and normal saline into the ME cavity, the osmolarity of the remaining fluid was determined, short- and long-term. Clear osmotic pressure gradients were found between amniotic fluid (low pressure), fetal blood (higher pressure) and the fluid in the fetal ME (intermediate between them). The MEs into which normal saline had been introduced developed negative pressure and, over several days, were cleared of fluid. When serum was applied, ME pressure remained close to atmospheric and the fluid was not cleared. Hypotonic saline application led to an increase in the osmotic pressure in the fluid remaining in the ME. It is concluded that most of the amniotic fluid is cleared from the neonatal ME cavity by water outflow into the blood due to osmotic pressure gradients.

The herbal medicine, sairei-to, enhances the mucociliary activity of the tubotympanum in the healthy guinea pig

Mucociliary dysfunction in the tubotympanum is deeply reflected in the clinical manifestations of otitis media with effusion (OME), and clinical application of pharmacological agents with ciliostimulatory action might therefore enhance the mucociliary clearance function of the tubotympanum to more effectively eliminate middle ear effusions to the pharynx. A herbal medicine, sairei-to, enhances the in vitro ciliary activity of the middle ear during culture. However, this ciliostimulatory effect is not always applicable to the mucociliary system in situ, which may be deteriorated following oral administration of sairei-to. The present study therefore aimed at investigating the in vivo effect of sairei-to on the mucociliary system in the tubotympanum of the guinea pig. Thirty healthy guinea pigs were used. Ten animals were treated with oral administration of physiologic saline solution for 14 successive days. The remaining animals were treated with oral administration of 120 or 600 mg/kg body weight of sairei-to for 14 successive days. Each animal was used for examination of the ciliary activity and mucociliary clearance time of the tubotympanum, 24 h after the final treatment. No significant changes in either ciliary activity or mucociliary clearance time of the tubotympanum were observed upon administration of 120 mg/kg of sairei-to, which was equivalent to the clinical human dosage. By contrast, oral administration of 600 mg/kg of sairei-to significantly enhanced the ciliary activity, but failed to significantly accelerate mucociliary clearance in the tubotympanum, although the mean value of the clearance time became shorter. Therefore, our results suggest that sairei-to to some extent stimulates the function of the mucociliary system. In conclusion, the herbal medicine, sairei-to, might be useful in the treatment of OME, and preventive administration of this drug may be a new therapy in the treatment of recurrent OME.

The effects of in vitro cotitine on nasal ciliary beat frequency

Cotitine is one of the main metabolites of nicotine. It is stable and in vivo has a relatively long circulating half life. Nasal ciliated cells from non-smoking individuals were exposed in vitro to solutions of cotitine corresponding to serum levels in active and passive smokers. Ciliary beat frequency was measured by a computerized photometric technique. There was a significant drop in ciliary beat frequency compared with control ciliated cells in phosphate buffered saline. It is concluded that cotitine in active or passive smoking has a marked effect on ciliary function. It may be a factor leading to diminished mucociliary clearance and persistent middle ear effusion.

Nasal and middle ear ciliary beat frequency in chronic suppurative otitis media

The middle ear mucociliary system has been shown to have an important function in the clearance of effusions. Little is known, however, about its role in chronic suppurative otitis media (CSOM). The ciliary beat frequencies of middle ear mucosal biopsies and nasal brushings of 27 patients with CSOM were analysed using a computerized photometric technique. The ciliary beat frequency in the middle ear mucosa was significantly less than that in nasal mucosa. Frequency in ears of smoking patients was significantly lower compared with non-smoking patients. Nasal brushings were taken from 27 otherwise healthy age and sex-matched non-smoking controls and the ciliary beat frequency was very similar to nasal samples from patients with CSOM. Ear controls were obtained from otosclerotic patients undergoing tympanotomy and the beat frequency was significantly higher than in the ear of patients with CSOM. It is concluded that middle ear ciliary function is significantly reduced in CSOM, particularly in patients who smoke.

Smoking and middle ear ciliary beat frequency in otitis media with effusion

The middle ear mucociliary system has been shown to play an important role in clearing middle ear effusions. There is conflicting epidemiological evidence, however, as to whether exposure to tobacco smoke plays a significant role in persistence of middle ear effusion in patients with otherwise normal mucociliary function. Samples of middle ear mucosa from 33 patients with persistent otitis media with effusion (OME) were taken at myringotomy, together with corresponding nasal brushings. The aim of this study was to observe the mean ear ciliary beat frequency (CBF) and to compare it with nasal ciliary activity. Nasal brushings were collected from 33 age and sex matched non-smoking controls with no history of nasal atopy or topical nasal treatment. Ear CBF in OME was significantly reduced in comparison to paired nasal samples (p < 0.001). Ear CBF in adult OME patients who smoked or in children who were passive smokers was significantly less than in patients who were not exposed to cigarette smoke (p < 0.01). This study indicates that impaired ciliary function due to tobacco smoke exposure is an aetiological factor in persistent OME.

The prognostic value of mucociliary clearance in predicting success in tympanoplasty

Mucociliary and equipressive eustachian tube functions have been studied, using saccharin solution (five per cent sodium saccharinate) and tubal manometry respectively, in 58 ears with chronic disease undergoing tympanoplasty. The position of the perforation site determines the results as the poorest results are obtained from the posterior ones, positive cases (47 per cent) and mean transport time (37.7 minutes), compared to the greater percentage of positive cases (86 per cent) and mean transport time (22.2 minutes) for anterior perforations. When both parameters are analysed together there is a direct relationship between normal equipressive function and normal mucociliary transport time and between negative transport time and tubal blocking. Significant difference in transport times have been found for the anterior and posterior perforations being shorter for the anterior ones. When surgical outcome is correlated with mucociliary transport, the normal transport time percentage is seen to be considerably higher in the success group (50 per cent) than in the failure group (22 per cent).

Effect of the radioprotector WR2721 on irradiation-induced injury to ciliated cells of eustachian tube

Our previous studies revealed that injury to the ciliated cells of the eustachian tube may be the primary cause of irradiation-induced serous otitis media. The purpose of this study was to investigate the effects of the radioprotector WR2721 on irradiation-induced injury to ciliated cells of the eustachian tube (ET) in chinchillas. Twelve chinchillas were divided into two groups: the control group and the experimental group, which was pretreated with a single intraperitoneal dose of the radioprotector S-2-[3-aminopropylamino]ethylphosphorothioic acid (WR2721) 400 mg/kg. The two groups were exposed to 30 Gy of 13-MeV electrons in a single fraction to the area of the bullae and nasopharynx. Ciliary dysfunction was tested and ciliated cells of the ET were examined by scanning and transmission electron microscopy. Pretreatment with WR2721 was found to protect ciliated cells of the ET from irradiation injury.

Histamine-induced mucociliary dysfunction and otitis media with effusion

Histamine, which has been found in middle ear effusions, is a potent pharmacological mediator released at an early stage of allergic reactions or general inflammatory process, increasing permeability of small blood vessels. Histamine might be involved in the origin and chronicity of middle ear effusions. In this study we studied the effect of histamine on the mucociliary function. First we examined the effect of histamine and its H1 and H2 blockers on the ciliary activity in the middle ear. 10(-2) M of histamine deteriorated ciliary activity; however, at lower concentrations ciliostimulatory effects were demonstrated for histamine (between 10(-8) M and 10(-4) M). Such ciliostimulatory effects were not affected by diphenhydramine (H1-blocker) but were reduced by cimetidine (H2-blocker). Thus histamine stimulates ciliary activity by combining with H2-receptor. Intratympanic injection of 10(-4) M of histamine induced accumulation of middle ear effusions (MEEs). The volume of MEEs was largest at 1 day postinjection when its mucociliary clearance time was longest. Then the mucociliary clearance time became shorter, but it was still significantly longer than that of the control animal. Ciliary activity in the tubotympanum showed no recovery through the observation period. On the other hand, intratympanic injection of 10(-6) M of histamine produced MEEs at 1 and 3 days postinjection when the mucociliary clearance time was longer than that of the control group. At 8 days, when most ears did not demonstrate MEEs, the mucociliary clearance time and ciliary activity in the Eustachian tube and tympanic orifice reached the level of the control group. Our present study demonstrates that histamine can induce mucociliary dysfunction of the tubotympanum resulting in middle ear effusions, and that cilia, especially those present in the tube and the tympanic orifice, have a significant role in eliminating middle ear effusions.

Current concepts of mucociliary dysfunction in otitis media with effusion

From a survey of the literature on mucociliary function in the tubotympanum, it is clear that mucociliary activity and ciliary activity are deeply involved in the pathogenesis, pathology, and prognosis of otitis media with effusion. Ciliary function in the middle ear, especially in the tympanic orifice and the Eustachian tube, has an important role in the mucociliary clearance of surplus secretion to the pharynx. Our review demonstrates that ciliary activity in the tubotympanum is sensitive to a variety of pathological agents including bacteria, bacterial endotoxin, irritant gases, and irradiation, resulting in mucociliary dysfunction of the tubotympanum.

Ciliary activity in the tubotympanum during type I allergic reaction

The immune system is active in the tubotympanum and some middle ear diseases might be partially or exclusively immunologically mediated. However, the effect of an allergic reaction on the tubotympanic cilia remains to be elucidated. The response of normal tubotympanic cilia from the guinea pig was investigated in an in vitro experimental system to evaluate ciliary responsiveness without the influence of secretions. Mucosal samples were obtained from three different tubotympanic locations (Eustachian tube, and middle ear close to the tube (proximal site) and more distal to the tube (distal site)). Each mucosal sample was cultured in 2 ml of RPMI 1640 and 1 ml of heparinized venous blood from a nonallergic human subject, a patient with ragweed-sensitive nasal allergy, or 3 patients with Dermatophagoides farinae-sensitive nasal allergy. One microgram of D. farinae extracts was added in each chamber to evoke an in vitro allergic reaction, and the ciliary activity of the most active cell in each culture was monitored for up to 120 min. When D. farinae extracts were added into the chamber containing blood from subjects without sensitivity to D. farinae, no changes were induced in ciliary activity throughout the examination. When the same dose of allergens was added into the chamber containing blood from D. farinae-sensitive subjects, ciliary excitation was induced in the culture from the Eustachian tube and the proximal site. The peak and plateau of this phenomenon were observed at 30-40 min after the addition of the allergen, and a gradual slowdown to the baseline level was observed after the plateau. No ciliary depression was induced by an allergic reaction in the culture from the Eustachian tube or the proximal site. Such ciliostimulatory effects were correlated with D. farinae induced-percent histamine release from whole blood. In the cultures from the distal site, however, a gradual ciliodepression followed the peak of ciliary excitation. In conclusion, an in vitro allergic reaction affected the ciliary activity in the distal site, but such ciliary dysfunction was not observed in the Eustachian tube or the proximal site during such a reaction.

Influenza A virus-induced otitis media and mucociliary dysfunction in the guinea pig

There is much epidemiologic, clinical and laboratory evidence that viral infection is involved in otitis media with effusion (OME). However, few studies have demonstrated any direct influence of viruses on the tubotympanum. The purpose of this study was to establish the effect of influenza A virus having invaded the tubotympanum and so elucidate the possible mechanism by which this virus contributes to the pathogenesis of OME. Eighty guinea pigs with normal otoscopic findings were inoculated with 0.2 ml suspension of influenza A (3.3 x 10(8) PFU/ml) into the tympanic cavity through the tympanic membrane. To serve as controls, the same number of guinea pigs were injected with 0.2 ml of physiologic saline solution into the tympanic cavity. At 3, 7, 14, and 28 days postinoculation, they were used for examination of the mucociliary function. Middle ear effusions as well as mucociliary dysfunction were observed only in the animals inoculated with the virus. The ciliary activity in the bulla was declined at any time examined. On the other hand, the ciliary activity in the Eustachian tube and the tympanic orifice was slightly lowered between 7 and 14 days, but the level was not different from that of the controls. However, the number of active ciliated cells (showing more than 500 beats/min) was significantly smaller than that of the controls. The mucociliary clearance time of the tubotympanum was more prolonged than that of the controls at 3, 7, and 14 days, and returned to the control level at 28 days. A variety of morphological changes were observed in the tubotympanum treated with the virus. Major pathologies observed included general inflammatory cell infiltration, vacuolation and other degeneration of ciliated cells, and vascular damage and increased vascular permeability. Regeneration of cilia or ciliated cells followed the degeneration, which included an increased number of basal cells and newly formed centrioles. However, the viral infection also affected the epithelial cells with new centrioles. Our study demonstrates that viral infection can evoke mucociliary dysfunction of the tubotympanum and create increased susceptibility to bacteria. Therefore, viral infection may enhance bacterial infectious processes in the tubotympanu thereby contributing to the occurrence of OME.

Human adenoidal organ culture: a model to study nontypable Haemophilus influenzae (NTHI) and other bacterial interactions with nasopharyngeal mucosa--implications in otitis media

Nontypable Haemophilus influenzae (NTHI) has become the predominant cause of both acute suppurative otitis media and chronic otitis media with effusion. It has now been well-demonstrated that both outer membrane proteins and restriction fragment analysis of the bacterial genomes of concomitant nasopharyngeal and middle ear effusion isolates of NTHI are identical. It is therefore of critical importance to understand the mechanisms whereby bacteria that are present in normal healthy children in small numbers become the predominant organism in the nasopharynx in otitis media. The studies presented here suggest that nontypable Haemophilus influenzae can effectively decrease ciliary function as measured by stroboscopic illumination of ciliary beat frequency on human adenoidal organ culture. This organism also produces significant histopathologic and ultrastructural damage to the epithelial cells and cilia of adenoid organ culture, demonstrated by both light microscopy and scanning electron microscopy. The data suggest the following hypothesis: nontypable Haemophilus influenzae can destroy mucociliary function and allow increased bacterial replication in the mucus overlying the nasopharyngeal mucosa. The mucociliary system of the eustachian tube may also be involved in a similar manner, thus allowing bacteria to enter the middle ear space via the eustachian tube.

Mucociliary disease of the middle ear during experimental otitis media with effusion induced by bacterial endotoxin

Lipopolysaccharide (10 micrograms/mL) derived from Klebsiella pneumoniae was injected into the middle ear of guinea pigs. The animals were killed painlessly on days 1, 3, and 7 after inoculation, and the mucosal samples from two sites within the tympanic cavity, close to the tympanic orifice and distal to the orifice, were examined for ciliary activity and epithelial morphology. At day 1 and day 3 serous effusion was observed and deterioration of ciliary activity and morphologic changes were observed. No effusion was recognized at day 7, when the ciliary activity in the distal mucosa was still diminished and that in the proximal mucosa had recovered to a normal level. Our data have shown that lipopolysaccharide extracted from K pneumoniae can produce otitis media with effusion in laboratory animals, and dysfunction of cilia due to lipopolysaccharide probably is responsible for the accumulation of middle ear effusion. The mucociliary system is indeed an important defense system and failure of such a system, especially in the mucosa close to the tympanic orifice, can cause the buildup of effusions.

Prognosis of secretory otitis media in relation to viscoelasticity of effusions in children

Both elasticity (G') and viscosity (eta') of middle ear effusions (MEEs) were measured with an oscillating sphere magnetic rheometer and compared with continuance of fluid retention in 93 ears of 69 children with otitis media with effusion (OME). The ears were divided into four groups according to the viscoelastic properties of MEEs at the first myringotomy. Eight-four percent of the ears in group 2 were free from effusion within 4 months; the difference from the other groups was statistically significant. These results indicate that the mucociliary clearance function plays an important role in the process of recovery from OME.

Acute effects of sulfur dioxide exposure on the middle ear mucosa

A variety of atmospheric pollutants are known to depress mucociliary function in the respiratory system. Since the mucociliary function in the middle ear is similar, and the middle ear may be invaded by atmospheric pollutants, we decided to investigate the possible contribution of sulfur dioxide to middle ear effusion. Guinea pigs were exposed for 24 hours to 300 ppm of sulfur dioxide or air. Immediately after exposure, ciliary activity and epithelial structure were examined close to the tympanic orifice (proximal site) and more distal to it (distal site). In the animals exposed to sulfur dioxide, no effusion was found in the tympanic cavity. Ciliary activity was reduced only in the distal site. Electron microscopy demonstrated hypersecretion in the proximal site and severe pathologic changes in the distal site. Although the normally functioning cilia in the proximal site may prevent retention of surplus secretions in the ear, sulfur dioxide may promote middle ear effusion when combined with other detrimental factors, because it stimulates mucus secretion in the proximal site and impairs ciliary function in the distal site.

Ciliary activity on adenoids of patients with otitis media with effusion

Ciliary activity of the adenoidal surface in patients with otitis media with effusion (OME) was evaluated by a photoelectric method. Three groups of patients were compared: a non-OME group whose members had experienced no episode of OME; a middle ear effusion (MEE)-negative OME group whose members had an episode of recurrent OME but no MEE during the month preceding the operation; and an MEE-positive OME group whose members were experiencing an episode of recurrent OME with MEEs when tissue was taken for examination. To serve as a comparison, the ciliary activity in the central pharynx of normal guinea pigs was evaluated using the same technique. The ciliary activity in all patients was significantly lower than that in normal guinea pigs. No significant difference in ciliary activity was apparent between the non-OME group and the MEE-negative OME group. However, both were significantly higher than the ciliary activity of the MEE-positive OME patients. The following findings are drawn from our data: ciliary activity on the surface of hypertrophic adenoids is depressed, and patients with OME have reduced ciliary activity compared with those who have no otitis media or those who have otitis media without effusion.

Reversibility of reduced ciliary activity on adenoids of patients with otitis media with effusion following culture

We have studied the ciliary activity of the pharyngeal epithelium on adenoids obtained from patients with recurrent otitis media with effusion to assess indirectly the ciliary activity in the Eustachian tube. In conclusion, the following has been speculated from the present study: (1) middle ear effusions depress the ciliary activity; and (2) recovery of the reduced ciliary activity can be achieved in an effusion-free environment inasmuch as the ciliated cells have not undergone organic changes. Prompt elimination of the effusion, if present, is of critical importance for the recuperation of tubotympanic drainage, because a positive therapeutic effect resulting from elimination of the effusion can only be possible in early phase of the disease, before irreversible morphological lesions have occurred.

Ultrastructure of mucous blanket in otitis media with effusion

We used transmission electron microscopy to study the mucous blanket of the promontory from children with otitis media with effusion. The vast majority of the epithelial cells were secretory, and the rest were ciliated. The mucous blanket consisted of the electron-lucent periciliary fluid and the mucous layer. In the mucous layer, two layers were identified: an inner layer with migrating cells, and an outer layer with specks. Moreover, there was a lucent zone over the nonciliated surface that was as high as the microvilli. The thickness of the periciliary layer was predominantly as great as that of the ciliary tips, which just make contact with the mucous layer; however, the mucous layer occasionally penetrated into the periciliary space. These findings indicated that there is a mucociliary dysfunction in the middle ear caused by a decrease in the number of ciliated cells, and an abnormal interaction between cilia and mucus that would interfere with ciliary movement. Thus, such a system would fail to transport the mucous blanket.

Experimental otitis media with effusion induced by lipopolysaccharide from Klebsiella pneumoniae: mucociliary pathology of the middle ear

We inoculated 100 micrograms/ml of lipopolysaccharide (LPS) from Klebsiella pneumoniae into the tympanic cavity of guinea pigs and examined the mucociliary pathology in the middle ear. Serous effusion was observed in the tympanic cavity of every animal on the first, third, and seventh day following the procedure, but the volume of the effusion had decreased to 0.2 ml on day 7. By that time, the ciliary activity in the opening to the eustachian tube within the middle ear had recovered to some extent, but in the middle ear distal to the opening no recovery was apparent. Our results show that cilia close to the eustachian tube play a more significant role in middle ear clearance than those in the middle ear distal to the tube. Compared with our previous study using 10 micron/ml of LPS, this study also demonstrates that inoculations with a higher concentration of LPS induces longer-term middle ear effusions.

Abnormalities of cilia in the middle ear in chronic otitis media

We studied the fine structure of nasal and middle ear mucosa in 18 patients with chronic otitis media, comparing them with ten age-matched control patients. Electron microscopy revealed no single fundamental defect of cilia in the tissue samples; however, patients with chronic otitis media had a significantly higher incidence of abnormal cilia in the middle ear without correlating abnormalities of nasal cilia. These findings indicated that ciliary anomalies, including deletion of ciliary microtubules, presence of supernumerary tubules, and fusion of cilia, occur as a result of infection or inflammation. Such abnormalities would impair normal mucociliary clearance and exacerbate clinical complications.

The effect of carbon dioxide on the activity of cilia. A study on rabbit sinus mucosa in vitro

The relation of ciliary activity to the partial pressure of carbon dioxide was studied with a photoelectric method on rabbit sinus mucosa in vitro. A dose-response relationship was found, where by ciliary activity was impaired at pCO2 above 5 kPa. The effect of elevated partial pressure of carbon dioxide on ciliary activity in secretory otitis media and sinusitis is discussed.