The effect of middle ear effusions from children on in vitro ciliary activity

What have we learned from murine models of otitis media?

Otitis media (OM) is a common cause of childhood hearing loss. The large medical costs involved in treating this condition have meant that research to understand the pathology of this disease and identify new therapeutic interventions is important. There is evidence that susceptibility to OM has a significant genetic component, although little is known about the key genetic pathways involved. Mouse models for disease have become an important resource to understand a variety of human pathologies, including OM, due to the ability to easily manipulate their genetic components. This has enabled researchers to create models of acute OM, and has aided in the identification of a number of new genes associated with chronic disease, through the use of mutagenesis programs. The use of mouse models has identified a number of key molecular signalling pathways involved in the development of this condition, with genes identified from models shown to be associated with human OM.

[Evolution of the tubotympanal mucociliary system activity evaluated with scintigraphy, after ventilation tube insertion in adults with chronic otitis media with effusion]

INTRODUCTION AND GOALS

Tubotympanal mucociliary function is damaged in patients with otitis media with effusion. Our objective was to study its situation and recovery after timopanostomy tube insertion.

METHODS

We evaluated the mucociliary activity of the ear and Eustachian tube with scintigraphy in four groups of adults with chronic otitis media with effusion after ventilation tube insertion. The test was performed on 3 days (Group I), 6 days (Group II), 9 days (Group III) and 12 days (Group IV) after tympanostomy tube insertion.

RESULTS

After excluding some patients with limited otorrhea, the percentages of patients that normalised mucociliary function in the different groups were: Group I, 0 of 13, 0%; Group II, 4 of 15 patients, 26,6%; Group III, 14 de 18 cases, 88,8%; and, in Group IV, 18 of 18, 100%.

CONCLUSIONS

Mucociliary function is altered in patients with chronic otitis media with effusion. With the insertion of tympanostomy tubes, mucociliary clearance is restored progressively, reaching normal after 12 days in all the patients.

The ciliary beat frequency of middle ear mucosa in children with chronic secretory otitis media

The chronic secretory otitis media (CSOM) is a common disease in children. Its cardinal symptoms are recurrent middle ear effusions and conductive hearing loss. Until today, the pathophysiological mechanism of this disease remains unknown. The correlation with adenoids and tubal dysfunction during childhood seems to be obvious, but the origin of middle ear effusions still has to be clarified. It is known that the CSOM affects the mucociliary system in several ways. In order to find out more about these correlations, the ciliary beat frequency was examined in 123 samples of infantile middle ear mucosa suffering from CSOM. Samples were surveyed using a stroboscopic microscopy method. The results of this study showed a significant decrease of ciliary beat frequency (CBF) to an average of 7.4 s(-1) in children with a CSOM. The healthy group of control showed a frequency of 10.1 s(-1). The measured CBF dataset was correlated with microbiological findings. We found a typical bacterial profile in nearly all the cases that were examined but were unable to find a specific bacterium decreasing CBF. This study provides evidence for the diminution of CBF in cases of CSOM in comparison to a healthy control group. Our findings emphasize the importance of stopping the vicious circle of recurrent effusions by paracentesis or grommet insertion.

Human respiratory mucosa in a nonadhesive stationary organ culture system

Fragments of human adenoid tissue were transferred to a nonadhesive, stationary organ culture system. The culture period was 40 days. In culture, beating cilia could be observed at the surface of the fragments. Light microscopy, scanning electron microscopy, and transmission electron microscopy showed that the tissue fragments were covered by a multilayered, pseudostratified, ciliated epithelium. Beneath the epithelium was a basement membrane. At the start of the culture period, the central parts of the fragments were dominated by lymphocytes. These lymphocytes gradually disappeared and were replaced by a collagen-containing stroma with scattered fibroblasts. The tissue fragments can be used as an organ culture model for normal respiratory mucosa.