Changes in Cochlear Blood Flow Due to Endotoxin-Induced Otitis Media

Inner ear disturbances related to middle ear inflammation

The inner and middle ear are connected mainly through round and oval windows, and inflammation in the middle ear cavity can spread into the inner ear, which might induce a disturbance. In cases with intractable otitis media, attention should also be paid to symptoms related to the inner ear. In this paper, middle ear inflammation and related inner ear disturbances are reviewed with a focus on representative middle ear diseases (such as acute otitis media, chronic otitis media, otitis media with anti-neutrophil cytoplasmic antibody-associated vasculitis, eosinophilic otitis media, cholesteatoma with labyrinthine fistula, and reflux-related otitis media). Their clinical concerns are then discussed with reference to experimental studies. In these diseases, early diagnosis and adequate treatment are required to manage not only middle ear but also inner ear conditions.

Aminophylline restores glucocorticoid sensitivity in a guinea pig model of sudden sensorineural hearing loss induced by lipopolysaccharide

Glucocorticoids have been used to treat hearing loss and vestibular dysfunction for many years. However, some reports have indicated that a subset of patients with these disorders exhibit glucocorticoid insensitivity or resistance. A reduction in histone deacetylase 2 (HDAC2) activity and expression has been reported to play a critical role in glucocorticoid resistance. Here, we investigated the protective effects of aminophylline on HDAC2 expression and glucocorticoid sensitivity in lipopolysaccharide (LPS)-induced sudden sensorineural hearing loss in guinea pigs. We assessed hearing recovery in LPS-applied guinea pigs, which were either left untreated or were systemically treated with either dexamethasone, aminophylline, or a combination of the two. We utilized fluorescence microscopy and enzyme-linked immunosorbent assay to analyze the distribution patterns of HDAC2 and detect its levels in the cochlea. We used hematoxylin-eosin staining to examine cochlear histopathological changes. In the absence of treatment, significant hearing loss was detected in LPS-exposed animals. A synergistic effect was observed between aminophylline and dexamethasone in maintaining HDAC2 expression levels, preventing hearing loss in LPS-exposed animals and reducing cochlear damage. This study indicates that aminophylline can restore glucocorticoid sensitivity, which provides a new approach to treating patients with hearing disorders who are refractory to glucocorticoids.

Imaging analysis in cases with inflammation-induced sensorineural hearing loss

CONCLUSION

3D-FLAIR imaging is sensitive to inflammatory inner ear disturbances and may be a useful method in investigating the severity of inner ear disturbance in cases of inflammation-induced SNHL.

OBJECTIVE

To evaluate the usefulness of the three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) magnetic resonance imaging (MRI) sequence in investigating different etiology of inner ear disturbances in cases with inflammation-induced acute sensorineural hearing loss (SNHL).

PATIENTS AND METHODS

Five cases with inflammation-induced acute SNHL by different conditions are included in this study: acute meningitis, acute otitis media, and Wegener granulomatosis. Imaging analysis was performed using a three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) magnetic resonance imaging (MRI) sequence, and correlation between clinical symptoms and FLAIR abnormalities was evaluated.

RESULTS

In the affected ears in all cases, 3D-FLAIR revealed high pre-contrast signal and increased signal in the cochlea after the administration of gadolinium. Enhancement was still observed in the inner ear after several months with continuing nystagmus in those cases induced by meningitis and severe otitis media. In a case with Wegener granulomatosis, increased signal in the post-contrast images was stronger on the side of the cochlea with the worse hearing level.

Recurrent otitis media with effusion in preterm infants with histologic chorioamnionitis--a 3 years follow-up study

BACKGROUND

Recurrent otitis media with effusion (OME) is a leading cause of acquired hearing loss in childhood. Histological chorioamnionitis (HCA) is an important cause of preterm delivery and neonatal morbidity and mortality. Here, we tested the hypothesis of an association between recurrent OME during the first 3 years of life and HCA in very low birth weight (VLBW) infants.

METHODS

A total of 110 randomly selected VLBW preterm newborns with HCA and 135 gestational age and gender-matched, HCA-negative VLBW infants were evaluated prospectively during the first 3 years of life for the presence of OME, as diagnosed on the basis of otoscopy, type B or C tympanogram, ipsilateral absence of transient evoked otoacoustic emissions responses, and ipsilaterally increased threshold at diagnostic auditory brain responses evaluation. Potential risk factors for OME were also examined in the two groups.

RESULTS

The HCA-positive infants showed a approximately six times higher frequency of recurrent OME (P<0.0001), increased frequency (>5/yr) of clinical otitis media episodes (P=0.000020), approximately five times higher frequency of adenoid hypertrophy (P<0.00001), a significant seasonal pattern of birth with autumn predominance (P<0.00001), and the first OME occurred earlier (P<0.0001), as compared to the HCA-negative counterparts. Recurrent OME was significantly associated with HCA (O.R.=17.76, 95% CI: 8.98-35.13, P<0.00001), adenoid hypertrophy (O.R.=9.96, 95% CI: 5.17-19.18, P<0.00001), frequency of acute otitis episodes >5/yr (O.R.=8.91, 95% CI: 1.96-40.41, P=0.0005), and birth in autumn (O.R.=5.58, 95% CI: 2.79-11.12, P<0.00001).

CONCLUSIONS

These findings indicate that HCA is a previously unrecognized risk factor for the development of recurrent bilateral OME in VLBW preterm infants during the first 3 years of life.

Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging investigation of inner ear disturbances in cases of middle ear cholesteatoma with labyrinthine fistula

OBJECTIVE

To investigate the cause of inner ear disturbances in cases of middle ear cholesteatoma with labyrinthine fistula.

SETTING

University hospital.

STUDY DESIGN

Prospective case study.

PATIENTS

Eight patients who were scheduled to undergo surgery for middle ear cholesteatoma with labyrinthine fistula were included in this study.

INTERVENTION

Imaging analysis was performed using a 3-dimensional fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging sequence.

MAIN OUTCOME MEASURES

Three-dimensional FLAIR findings were compared with clinical symptoms associated with inner ear disturbance and surgical observations of the fistula.

RESULTS

Three-dimensional FLAIR in 6 patients revealed areas of high signal intensity in the inner ears on the affected sides and areas with increased signal after the administration of gadolinium, especially in cases accompanied by acute sensorineural hearing loss. These images were considered to be indicative of breakdown of the blood-labyrinth barrier due to middle ear cholesteatoma. This finding was also present in a patient with no clinical symptoms of inner ear disturbances.

CONCLUSION

Three-dimensional FLAIR images of the inner ear are valuable in evaluating labyrinthine fistula in patients with cholesteatoma. Future studies are needed to better understand the role of 3-dimensional FLAIR in predicting the severity of inner ear disturbance.

Upregulation of HSP by geranylgeranylacetone protects the cochlear lateral wall from endotoxin-induced inflammation

We investigated whether an acyclic polyisoprenoid antiulcer drug, geranylgeranylacetone (GGA), induces the expression of HSP70 in the rat cochlea. Immunoblotting revealed upregulation of HSP70 in the cochlea at 12 h after transtympanic (local) or oral (systemic) administration of GGA, and this increased at 24 h after administration. Positive immunohistochemical staining of HSP70 was observed in the hair cells, the spiral ganglion, the stria vascularis, the spiral ligament, and the perivascular portion of modiolar vessels. We therefore subsequently studied the effects of GGA as an HSP-inducer on inner ear trauma due to inflammation. Damage to the lateral wall due to inflammation induced by lipopolysaccharide inoculation was protected against by pretreatment with GGA, as assessed physiologically by measurement of cochlear blood flow and morphologically by electron microscopy. The results of the present study suggest that GGA can protect the cochlea against other injuries including those induced by noise, ototoxic drugs, and ischemia by upregulating HSP70.