Experimental study of local inner ear gene therapy for controlling autoimmune sensorineural hearing loss.

This study aimed to investigate the efficacy of gene therapy for treating autoimmune sensorineural hearing loss (ASHL) via local administration of a recombinant adenovirus vector containing the Fas ligand or interleukin IL-10 gene. Guinea pigs were divided into four groups, with different microinjections in the scala tympani. Group A were injected with FasL-EGFP, B with IL-10-EGFP, C with EGFP, and D with artificial perilymph. Seven days later, auditory brain-stem response (ABR) was tested, and the temporal bone was stained and observed by light microscopy. The spiral ligament and basement membrane were observed using transmission electron microscopy. FasL and IL-10 expression were examined using immunofluorescence histochemistry. Immunohistochemical analysis showed that the recombinant adenovirus vector in Groups A, B, and C can transfect the stria vascularis, the spiral ligament, the organ of Corti, the spiral ganglion, the region surrounding the small blood vessel in the modiolus, and the cochlear bone wall. Compared with those in Groups C and D, the ABR wave III mean thresholds were significantly lower and the inner ear immunoinflammatory responses in Groups A and B were significantly alleviated. Inhibition of immunoinflammatory response alleviated immunoinflammatory injury and auditory dysfunction. This technique shows potential as a novel therapy for ASHL.

Exogenous IL-4-expressing bone marrow mesenchymal stem cells for the treatment of autoimmune sensorineural hearing loss in a guinea pig model.

Bone marrow mesenchymal stem cells (BMSCs) expressing recombinant IL-4 have the potential to remediate inflammatory diseases. We thus investigated whether BMSCs expressing exogenous IL-4 could alleviate autoimmune sensorineural hearing loss. BMSCs isolated from guinea pigs were transfected with recombinant lentivirus expressing IL-4. A total of 33 animals were divided into three groups. Group A received scala tympani injection of IL-4-expressing BMSCs, and Group B received control vector-expressing BMSCs, and Group C received phosphate-buffered saline. The distribution of implanted BMSCs in the inner ears was assessed by immunohistochemistry and fluorescence microscopy. Auditory brain-stem response (ABR) was monitored to evaluate the auditory changes. Following BMSCs transplantation, the threshold levels of ABR wave III decreased in Groups A and B and significant differences were observed between these two groups (P < 0.05). Transplanted BMSCs distributed in the scala tympani and scala vestibuli. In some ears with hearing loss, there was a decrease in the number of spiral ganglion cells and varying degrees of endolymphatic hydrops or floccule. Following transplantation, the lentivirus-infected BMSCs migrated to the inner ear and produced IL-4. Our results demonstrate that, upon transplantation, BMSCs and BMSCs expressing recombinant IL-4 have the ability to remediate the inflammatory injury in autoimmune inner ear diseases.

Auditory function in women with autoimmune inner ear diseases and their offspring.

OBJECTIVE: The precise cause of congenital sensorineural hearing loss (CSNHL) is unclear in many cases. In a previous study we found that offspring from guinea pigs with autoimmune sensorineural hearing loss (ASNHL) exhibited signs of SNHL. Here we studied women with autoimmune inner ear diseases (AIED) and their offspring. Our aim was to determine if autoimmune damage may be one of the causes of CSNHL. METHODS: Thirty-eight pregnant women with AIED were recruited. Thirty-three had ASNHL; one with autoimmune delayed endolymphatic hydrops (ADEH) and four with autoimmune Meniere's disease (AIMD). The following were assessed in all women: audiogram, auditory brain stem response (ABR), otoacoustic emission (OAE), vestibular function test and presence of inner ear antigens. The following were assessed in offspring from these women: OAE, ABR and presence of inner ear antigens. RESULTS: Five of the 38 children born to women with AIED had SNHL (an incidence much higher than normal). OAEs were not inducible in these children shortly after birth or within 46-100 days after birth. Abnormal ABR findings were apparent in these five children and inner ear antigens were detected in three of the five children (the mother's of these children were also positive for inner ear antigens). CONCLUSIONS: These preliminary findings suggest that the prevalence of congenital ASNHL may be increased in offspring born to women with AIED.

[Analysis of the main components of inner ear antigens inducing autoimmune Meniere's disease in guinea pigs].

OBJECTIVE: To investigate the main components of inner ear antigens inducing autoimmune Meniere's disease (AIMD) in guinea pigs. METHODS: The guinea pigs were immunized with isologous crude inner ear antigens (ICIEAg). Then, the hearing function was measured with auditory brainstem response (ABR), the vestibular function was measured with electronystagmography (including spontaneous nystagmus and caloric test), and inner ear histopathological changes were observed by inner ear celloidin section with haematoxylin-eosin staining and observed under light microscope. According to these results, the AIMD-model animals from non-AIMD-model ones were distinguished. The special antibodies against ICIEAg in sera were measured with ELISA. The antigen-antibody reactions against different components of ICIEAg were detected by Western blotting with sera of AIMD and non-AIMD guinea pigs respectively. Then, we analysed the contrast between them and found the main components of the ICIEAg that were positive reaction in AIMD guinea pigs and negative reaction in non-AIMD guinea pigs. RESULTS: The result of ELISA demonstrated that the sera of both the AIMD and non-AIMD guniea pigs contained the special antibodies against ICIEAg after immunized with ICIEAg. The difference of the amount of antibody against ICIEAg between AIMD guinea pig group and non-AIMD guinea pig group was not significant. Western blotting assay showed only the sera of AIMD guinea pig contained the antibodies against the specific antigens with the molecular of 68 000, 58 000, 42 000 and 28 000. CONCLUSIONS: ICIEAg contain many different components, the AIMD might only happen in the guinea pigs in which the special immunization against the main components that could induce this kind of disorder appeared. The inner ear antigens with molecular of 68 000, 58 000, 42 000 and 28 000 might be the main components inducing AIMD in guinea pigs.

[Epidemiologic study on hearing impairment and ear diseases in old people].

OBJECTIVE: To investigate the prevalence of hearing impairment and ear diseases in old people and provide scientific data for drawing up the prevention and treatment strategies. METHODS: Using the probability proportion to size (PPS) method, 1261 people over 60 years were investigated in 40 clusters in Jiangsu Province with the WHO protocol. RESULTS: The prevalence of hearing impairment was 58.1% (the standardized rate: 59.5% in the whole country, 60.9% in Jiangsu province). Degrees of hearing impairment were mild (33.1%), moderate (17.8%), severe (5.9%) and profound (1.3%). The prevalence of hearing disability was 25.0% (the standardized rate: 26.6% in the whole country, 28.1% in Jiangsu province). There were significant difference of the prevalence between male and female, as well as urban and rural, and different ages. The prevalence of the ear diseases was auricle malformation (0.2%), wax (1.7%), otitis externa (0.1%), fungi (0.5%), serous otitis media (1.2%), chronic suppurative otitis media (1.6%), dry perforation of tympanic membrance (2.3%). The causes of hearing impairment were ear diseases (2.9%), non-infectious condition (92.6%), genetic condition (0.3%) and undetermined causes (4.2%). Of which, 31.1% of persons needed hearing aids while 2.3% of persons needed medicine treatment, but 0.9% of persons needed non-urgent surgery and 1.0% of persons needed other treatment. CONCLUSIONS: The prevalence of hearing impairment and disability in the old rised obviously than the last investigation in 1987. It was a heavy burden for social development in China. The government and the whole society should take more concern about the problem. The scientific strategies of prevention and treatment were urgently needed and implemented.

[Inner ear physiological function and pathological morphology in the offsprings of sensorineural hearing loss female guinea pigs induced by homogeneous inner ear antigens immunizing].

OBJECTIVE: To explore if the autoimmune of anti-labyrinth tissues acts as one of pathogenic cause by observing the inner ear physiological functions and pathological morphology changes of offspring of autoimmune sensorineural hearing loss (ASHL) female guinea pig. METHODS: The pregnant guinea pigs were immunized with homogeneous inner ear antigens (HIEAg), then, the hearing function were measured with EcochG [inspecting items including acoustic nerve compound action potential (cAP), summation potential (-SP) and cochlear microphone potential (CM)], while the vestibular function were measured with electronystagmography (inspecting items including spontaneous nystagmus and caloric test), inner ear Celloidin section with haematoxylin-eosin dyeing and being inspected under light microscope. The special antibodies in serum and special lymphocyte immune reaction were measured with ELISA and 3H-TdR intermingling lymphocyte transform test in all female guinea pigs and their offspring guinea pigs. RESULTS: In 7 offspring guinea pigs, 3 animals appeared sensorineural hearing loss. Immuno-inflammation pathologic changes happened in the labyrinth (including the number of bipolar cells reduced and some kind of inflammatory cells infiltrated in spiral ganglion and endolymphatic hydrops et al.), and rise of special antibodies against HIEAg in serum. There were no any obvious abnormity found in non-ASHL pregnant and normal contrastive pregnant guinea pigs and their offspring. CONCLUSIONS: In this study, some of ASHL female guinea pig's offspring demonstrated different grades of sensorineural hearing loss and inner ear inflammation, and the special humoral and cellular immune reaction against HIEAg, which could be induced by autoimmune inflammation against inner ear tissues antigens with special antibodies (maybe including special cellular immune reaction) from matrix through placental barrier. This result suggests that the factor of autoimmune against inner ear tissue antigens may be one of pathogenic causes inducing non-heritage congenital sensorineural hearing loss.

[Endoscopic technique utilized into the selective vestibular neurotomy by retrosigmoid approach].

OBJECTIVE: To investigate the micro-wound technique and the signification of reducing brain tissue oppression and complication at the surgery with utilizing endoscopic technique during the operation of selective vestibular neurotomy (SVNT) by retrosigmoid approach. METHODS: Twelve patients were preceded the SVNT by retrosigmoid approach (as routine operation group, ROG), and nine patients were utilized endoscope for review and neurotomy during the process of the SVNT by retrosigmoid approach (as endoscopic operation group, EOG). All of them were examined by auditory level, vestibular function, facial nerve function and observed of clinical situation (including complication and equilibrium function and so on) before and after operation. RESULTS: Two patients appeared cerebral edema and demanded the treatment of dehydration and depressing intracranial pressure in ROG after operation. In each group, the average auditory threshold in 2 patients rose more than 15 dB post-operation. The interval time of average equilibrium function compensation is (29.00 +/- 9.60) d in ROG and (28.56 +/- 7.91) d in EOG after surgery. Peripheral facial paralysis didn't happen to any patient in two groups. After follow-up two years post-operation, the vertigo recurred in 2 patients (4 times and 1 times, respectively) in ROG and 1 patient (2 times) in EOG. CONCLUSIONS: The SVNT by retrosigmoid approach is widespread adopted presently as expedience and safe surgery method for Ménière's disease, and could effectively eliminate vertigo and simultaneously conserve the hearing function and the integration of facial nerve. This surgery process became micro-wound, more facility and safe following the endoscopic technique utilization, which could reduce the brain tissues depression and trauma and could not cause any of complications. Therefore, the endoscopic operation of the SVNT by retrosigmoid approach is worth to clinically popularize as the therapy method of vertigo for the patients of Ménière's disease, especially who associate with contralateral sensorineural hearing loss.