Neutrophil Extracellular Traps and Fibrin in Otitis Media: Analysis of Human and Chinchilla Temporal Bones.

Background: Bacterial resistance in acute otitis can result in bacterial persistence and biofilm formation, triggering chronic and recurrent infections. Objective: To investigate the middle ear inflammatory response to bacterial infection in human and chinchilla temporal bones. Design, Setting, and Participants: Six chinchillas underwent intrabullar inoculations with 0.5 mL of 106 colony-forming units (CFUs) of Streptococcus pneumoniae, serotype 2. Two days later, we counted bacteria in middle ear effusions postmortem. One ear from each chinchilla was processed in paraffin and sectioned at 5 µm. The opposite ear was embedded in epoxy resin, sectioned at a thickness of 1 µm, and stained with toluidine blue. In addition, we examined human temporal bones from 2 deceased donors with clinical histories of otitis media (1 with acute onset otitis media, 1 with recurrent infection). Temporal bones had been previously removed at autopsy, processed, embedded in celloidin, and cut at a thickness of 20 µm. Sections of temporal bones from both chinchillas and humans were stained with hematoxylin-eosin and immunolabeled with antifibrin and antihistone H4 antibodies. Main Outcome Measures: Histopatological and imminohistochemical changes owing to otitis media. Results: Bacterial counts in chinchilla middle ear effusions 2 days after inoculation were approximately 2 logs above initial inoculum counts. Both human and chinchilla middle ear effusions contained bacteria embedded in a fibrous matrix. Some fibers in the matrix showed positive staining with antifibrin antibody, others with antihistone H4 antibody. Conclusions and Relevance: In acute and recurrent otitis media, fibrin and neutrophil extracellular traps (NETs) are part of the host inflammatory response to bacterial infection. In the early stages of otitis media the host defense system uses fibrin to entrap bacteria, and NETs function to eliminate bacteria. In chronic otitis media, fibrin and NETs appear to persist.

A three-dimensional analysis of the endolymph drainage system in Ménière disease.

OBJECTIVES/HYPOTHESIS: To measure the volume of the endolymph drainage system in temporal bone specimens with Ménière disease, as compared with specimens with endolymphatic hydrops without vestibular symptoms and with nondiseased specimens STUDY DESIGN: Comparative human temporal bone analysis. METHODS: We generated three-dimensional models of the vestibular aqueduct, endolymphatic sinus and duct, and intratemporal portion of the endolymphatic sac and calculated the volume of those structures. We also measured the internal and external aperture of the vestibular aqueduct, as well as the opening (if present) of the utriculoendolymphatic (Bast's) valve and compared the measurements in our three study groups. RESULTS: The volume of the vestibular aqueduct and of the endolymphatic sinus, duct, and intratemporal endolymphatic sac was significantly lower in the Ménière disease group than in the endolymphatic hydrops group (P <.05). The external aperture of the vestibular aqueduct was also smaller in the Ménière disease group. Bast's valve was open only in some specimens in the Ménière disease group. CONCLUSIONS: In temporal bones with Ménière disease, the volume of the vestibular aqueduct, endolymphatic duct, and intratemporal endolymphatic sac was lower, and the external aperture of the vestibular aqueduct was smaller as compared with bones from donors who had endolymphatic hydrops without vestibular symptoms and with nondiseased bones. The open status of the Bast's valve in the Ménière disease group could be secondary to higher retrograde endolymph pressures caused by smaller drainage systems. These anatomic findings could correlate with the reason that some patients with hydrops develop clinical symptoms, whereas others do not. LEVEL OF EVIDENCE: N/A Laryngoscope, 127:E170-E175, 2017.

Pathologic Changes of the Peripheral Vestibular System Secondary to Chronic Otitis Media.

OBJECTIVE: To evaluate the histopathologic changes of dark, transitional, and hair cells of the vestibular system in human temporal bones from patients with chronic otitis media. STUDY DESIGN: Comparative human temporal bone study. SETTING: Otopathology laboratory. SUBJECTS AND METHODS: To compare the density of vestibular dark, transitional, and hair cells in temporal bones with and without chronic otitis media, we used differential interference contrast microscopy. RESULTS: In the chronic otitis media group (as compared with the age-matched control group), the density of type I and type II hair cells was significantly decreased in the lateral semicircular canal, saccule, and utricle (P < .05). The density of type I cells was also significantly decreased in the chronic otitis media group in the posterior semicircular canal (P = .005), but that of type II cells was not (P = .168). The mean number of dark cells was significantly decreased in the chronic otitis media group in the lateral semicircular canal (P = .014) and in the posterior semicircular canal (P = .002). We observed no statistically significant difference in the density of transitional cells between the 2 groups (P > .1). CONCLUSION: The findings of our study suggest that the decrease in the number of vestibular sensory cells and dark cells could be the cause of the clinical symptoms of imbalance of some patients with chronic otitis media.

Epitympanum volume and tympanic isthmus area in temporal bones with retraction pockets.

OBJECTIVES/HYPOTHESIS: To compare the volume of the epitympanic space, as well as the area of the tympanic isthmus, in human temporal bones with retraction pockets to those with chronic otitis media without retraction pockets and to those with neither condition. STUDY DESIGN: Comparative human temporal bone study. METHODS: We generated a three-dimensional model of the bony epitympanum and measured the epitympanic space. We also compared the area of the tympanic isthmus. RESULTS: The mean total volume of the epitympanum was 40.55 ± 7.14 mm3 in the retraction pocket group, 50.03 ± 8.49 mm3 in the chronic otitis media group, and 48.03 ± 9.16 mm3 in the neither condition group. The mean volume of the anterior, lateral, and medial compartments in temporal bones in the retraction pocket group was significantly smaller than in the two control groups (P < 0.05). Total epitympanic volume was also significantly smaller in the retraction pocket group than in both control groups (P < 0.05). The mean area of the tympanic isthmus was significantly smaller in the retraction pocket group (8.11 ± 2.44 mm2 ) than in the chronic otitis media group (9.82 ± 2.06 mm2 ) or the neither condition group (10.66 ± 1.78 mm2 ) (P < 0.05). CONCLUSION: Our data indicate that temporal bones with retraction pockets have a smaller volume bony epitympanum and a smaller tympanic isthmus area as compared with temporal bones from both control groups. The smaller volume tympanic isthmus in the retraction pocket group may suggest that a blockage in the aeration pathways to the epitympanum could create dysventilation, resulting in negative pressure and ultimately in retraction pockets and cholesteatomas. LEVEL OF EVIDENCE: NA Laryngoscope, 126:E369-E374, 2016.

Quantitative assessment of vestibular otopathology in otosclerosis: A temporal bone study.

OBJECTIVES/HYPOTHESIS: To determine if peripheral vestibular otopathology is present in human temporal bones with otosclerosis. STUDY DESIGN: Comparative human temporal bone study. METHODS: Seventy-four human temporal bones from 46 subjects with otosclerosis (mean age of 61 ± 18 years) and 20 within histologically normal limits from 17 subjects (mean age of 59 ± 14 years) were included in this study. Temporal bones with otosclerosis were divided into those with and without endosteal involvement. Using differential interference contrast microscopy at 1008× magnification, type I and type II vestibular hair cell counts were performed on each vestibular sense organ in which the neuroepithelia was oriented perpendicular to the plane of section. The organ-specific cell densities (cells/0.01 mm(2) surface area) were compared between the groups with and without endosteal involvement, and also compared to counts in the nonotosclerosis control group using Student's t-test. RESULTS: Mean type I and type II hair cell densities of all vestibular structures in the group with endosteal involvement were significantly lower compared to the group without endosteal involvement. Mean type I and type II hair cell densities of all vestibular structures in the group with endosteal involvement were also significantly lower compared to the control group, but they were not in the group without endosteal involvement compared to the control group. CONCLUSION: Endosteal involvement of otosclerotic foci is associated with vestibular hair cell loss that may contribute to the vestibular symptoms in otosclerosis. LEVEL OF EVIDENCE: N/A. Laryngoscope, 126:E118-E122, 2016.

Cloning and characterization of rat neuronal apoptosis inhibitory protein cDNA.

The human neuronal apoptosis inhibitory protein (NAIP) gene was originally discovered because of its deletion in infantile spinal muscular atrophy (SMA), a childhood genetic disorder characterized by motor neuron loss and progressive paralysis with muscular atrophy. Although SMA is now known to be caused by deletions of survival motor neuron (SMN), the fact that NAIP is an anti-apoptotic protein is consistent with the NAIP gene modifying SMA severity. Here we report the cloning of a 1.5 kb rat NAIP cDNA fragment which contains BIR-3 (third baculovirus inhibitory repeat) domain. This fragment shows 78% homology to the human NAIP and 86% homology to the murine counterpart. We have investigated the distribution of NAIP mRNA expressing neurons by in situ RT-PCR technique in the rat central nervous system (CNS). Although all of the neurons appeared to express NAIP mRNA ubiquitously, pronounced elevation of NAIP mRNA expression was observed in the areas innervated by glutamatergic neurons after kainic acid (KA) injection. We have raised an anti-rat NAIP antiserum in rabbits using NAIP cDNA and recombinant rat NAIP, and carried out an immunohistological investigation. We observed highly immunoreactive neuronal subpopulations in the retinal ganglion, cerebral cortex, hippocampus, basal forebrain, thalamus, areas of midbrain, Purkinje cells of the cerebellum, and motor neurons in the spinal cord. Increased immunoreactivity of glutamatergic neurons was also observed broadly in the CNS after KA treatment. This study provides additional evidence that expression of mRNA and gene products of NAIP seem to be regulated in response to excessive stimuli or injuries in rat CNS, and these results are compatible with an anti-apoptotic role of NAIP in acute SMA as well as in brain injuries.