Imaging the coordination of multiple signalling activities in living cells.

Cellular signal transduction occurs in complex and redundant interaction networks, which are best understood by simultaneously monitoring the activation dynamics of multiple components. Recent advances in biosensor technology have made it possible to visualize and quantify the activation of multiple network nodes in the same living cell. The precision and scope of this approach has been greatly extended by novel computational approaches (referred to as computational multiplexing) that can reveal relationships between network nodes imaged in separate cells.

Improvement of Suspected Eosinophilic Otitis Media with Targeted Biologic Therapy.

OBJECTIVE: To compare the responses of suspected eosinophilic otitis media to treatment with or without a targeted biologic therapy against interleukin-4 (IL-4), IL-5, or IL-13 signaling. STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: Subjects with type 2 chronic rhinosinusitis with nasal polyposis (CRSwNP), asthma, and otitis media who underwent treatment between 2005 and 2021. INTERVENTION: Treatment with targeted biologic therapy. MAIN OUTCOME MEASURES: Pre- and posttreatment nasal endoscopy, ear examination, and audiologic evaluation. RESULTS: Four hundred seventy-seven subjects with type 2 CRSwNP were treated between 2005 and 2021. Sixty-two had otitis media with pre- and posttreatment evaluation. Retrospective chart review assessed pre- and posttreatment exam findings, nasal endoscopy, audiometry, and tympanometry. Nineteen subjects received a biologic therapy, whereas 43 did not. Exam, endoscopy, and tympanometry were graded for severity and compared pre- and posttreatment. Subjective ear exam and tympanometry were significantly improved with biologic therapy (control = 0.05, biologic = 0.84, p = 9.3 × 10 -5 ; control = -0.1, biologic = 0.62, p = 0.0002). Conductive hearing loss as assessed by air-bone gaps did not change between groups (control = 1.2 dB better, biologic = 1.2 dB worse, p = 0.32). Nasal endoscopy findings improved with biologic therapy relative to the control group, although not statistically significant (control = 1.04, biologic = 1.36, p = 0.22). CONCLUSIONS: Biologic therapies targeting interleukin-4 (IL-4), IL-5, and IL-13 signaling are potential new treatments for eosinophilic otitis media. This is the largest study demonstrating improvement in subjects with suspected eosinophilic otitis media in response to biologic therapy, and immune modulation represents a novel treatment strategy for this challenging condition. PROFESSIONAL PRACTICE GAP AND EDUCATIONAL NEED: Current treatment strategies for otologic symptoms in eosinophilic disease are not tremendously effective or durable, resulting in a need for improved treatment options. LEARNING OBJECTIVE: To determine if targeted biologic therapy, often used for eosinophilic asthma and type 2 chronic rhinosinusitis with nasal polyposis, improves coexistent suspected eosinophilic otitis media. DESIRED RESULT: Treatment of suspected eosinophilic otitis media with targeted biologic therapy will result in improvement of otologic symptoms with a durable response compared with current treatment options. LEVEL OF EVIDENCE: Level IV. INDICATE IRB OR IACUC: Exempt. HUM00182703.

Rab13-dependent trafficking of RhoA is required for directional migration and angiogenesis.

Angiogenesis requires concomitant remodeling of cell junctions and migration, as exemplified by recent observations of extensive endothelial cell movement along growing blood vessels. We report that a protein complex that regulates cell junctions is required for VEGF-driven directional migration and for angiogenesis in vivo. The complex consists of RhoA and Syx, a RhoA guanine exchange factor cross-linked by the Crumbs polarity protein Mupp1 to angiomotin, a phosphatidylinositol-binding protein. The Syx-associated complex translocates to the leading edge of migrating cells by membrane trafficking that requires the tight junction recycling GTPase Rab13. In turn, Rab13 associates with Grb2, targeting Syx and RhoA to Tyr(1175)-phosphorylated VEGFR2 at the leading edge. Rab13 knockdown in zebrafish impeded sprouting of intersegmental vessels and diminished the directionality of their tip cells. These results indicate that endothelial cell mobility in sprouting vessels is facilitated by shuttling the same protein complex from disassembling junctions to the leading edges of cells.

Intraoperative Electrocochleography Correlates to Outcomes in Transmastoid and Middle Cranial Fossa Superior Semicircular Canal Dehiscence Repair.

OBJECTIVE: To determine the degree to which electrocochleography (ECoG) correlates with auditory and vestibular outcomes after repair of superior semicircular canal dehiscence (SSCD) via transmastoid (TM) and middle cranial fossa (MCF) approaches. STUDY DESIGN: Retrospective review. SETTING: Academic tertiary referral center. PATIENTS: Adults with SSCD who underwent repair between 2005 and 2019. INTERVENTION: Pre-, intra-, and postoperative ECoG. MAIN OUTCOME MEASURES: Patient-reported vestibular and auditory symptoms; pre-, intra-, and postoperative ECoG measures, dizziness handicap inventory (DHI) scores. RESULTS: Forty-six patients underwent SSCD repair (40 unilateral, six bilateral) between 2005 and 2019, including 24 MCF and 28 TM approaches. There were no differences in preoperative, intraoperative, or postrepair ECoG SP/AP values between the MCF and TM groups (p 0.12, 0.77, 0.58). Patients had subjective improvement in vestibular symptoms (or stable vestibular function in patients operated for predominantly auditory manifestations) with both approaches (MCF: 87.5%; TM: 92.3%; p 0.64). A successful outcome correlated with intraoperative SP/AP ratio normalization (p 0.0005). Similarly, DHI scores were similar in both groups preoperatively (p 0.66) and returned to their preoperative baseline postoperatively with both (p 0.52). Reported vestibular symptoms persisted or worsened more often in patients with migraine (66.6% vs. 28.9%, p 0.03), and with persistently abnormal ECoG measures, though the latter was not statistically significant in this population (38% vs. 15%, p 0.10). Patients had subjective improvement or stability in auditory symptoms using either approach (MCF: 96%; TM: 100%; p 0.62), also correlating with SP/AP ratio normalization (p 0.008). CONCLUSIONS: Correction of abnormal preoperative ECoG reliably correlates to patient symptom improvement after SSCD repair. No significant differences in postoperative outcomes were noted between patients undergoing TM versus MCF repair. Circumspection regarding the likelihood of an ideal outcome after SSCD repair should be exercised when counseling patients with concomitant migraine. DEFINE PROFESSIONAL PRACTICE GAP AND EDUCATIONAL NEED: It is not certain whether outcomes differ between the two dominant approaches for SSCD repair. Surgeons and patients would benefit from an intraoperative metric that reflects satisfactory plugging of SSCD. LEARNING OBJECTIVE: To highlight the reliability and unique utility of intraoperative ECoG and demonstrate the correlation between ECoG correction and symptom improvement for SSCD repair. DESIRED RESULT: To report subjective and objective outcomes following SSCD repair and encourage adoption of intraoperative ECoG monitoring. LEVEL OF EVIDENCE: Level V. INDICATE IRB OR IACUC: IRB review considers this study exempt (HUM00169949).

Catchment Profile of Large Cochlear Implant Centers in the United States.

OBJECTIVE: To characterize the catchment area and patient profile of large cochlear implant (CI) centers in the United States. STUDY DESIGN: Multi-institutional retrospective case series. SETTING: Tertiary referral CI centers. METHODS: Patients who underwent CI surgery at 7 participating CI centers between 2015 and 2020 were identified. Patients' residential zip codes were used to approximate travel distances and urban vs rural residential areas. RESULTS: Over the 6-year study period (2015-2020), 6313 unique CI surgical procedures occurred (4529 adult, 1784 pediatric). Between 2015 and 2019, CI procedures increased by 43%. Patients traveled a median 52 miles (interquartile range, 21-110) each way; patients treated at rural CI centers traveled greater distances vs those treated at urban centers (72 vs 46 miles, P < .001). Rural residents represented 61% of the patient population and traveled farther than urban residents (73 vs 24 miles, P < .001). Overall, 91% of patients lived within a 200-mile radius of the institution, while 71% lived within a 100-mile radius. In adults, multiple regression analysis redemonstrated an association between greater travel distances and (1) older age at the time of CI and (2) residential rural setting (both P < .001, r2 = 0.2). CONCLUSIONS: While large CI centers serve geographically dispersed populations, most patients reside within a 200-mile radius. Strategies to expand CI utilization may leverage remote programming, telemedicine, and strategic placement of new centers and satellite clinics to ameliorate travel burden.

Rho kinase inhibition rescues the endothelial cell cerebral cavernous malformation phenotype.

Cerebral cavernous malformations (CCM) are vascular lesions causing seizures and stroke. Mutations causing inactivation of one of three genes, ccm1, -2, or -3, are sufficient to induce vascular endothelial cell defects resulting in CCM. Herein, we show that loss of expression of the CCM1, -2, or -3 proteins causes a marked increase in expression of the GTPase RhoA. Live cell imaging with a RhoA-specific biosensor demonstrates increased RhoA activity with loss of CCM1, -2, or -3, with an especially pronounced RhoA activation in both the cytosol and the nucleus with loss of CCM1 expression. Increased RhoA activation was associated with Rho kinase-dependent phosphorylation of myosin light chain 2. Functionally, loss of CCM1, -2, or -3 inhibited endothelial cell vessel-like tube formation and extracellular matrix invasion, each of which is rescued by chemical inhibition or short hairpin RNA knockdown of Rho kinase. The findings, for the first time, define a signaling network for CCM1, -2, and -3 in CCM pathology, whereby loss of CCM1, -2, or -3 protein expression results in increased RhoA activity, with the activation of Rho kinase responsible for endothelial cell dysregulation. The results define Rho kinase as a therapeutic target to rescue endothelial cells from loss of CCM protein function.

Intraoperative Auditory Brainstem Response Results Predict Delayed Sensorineural Hearing Loss After Middle Cranial Fossa Resection of Vestibular Schwannoma.

OBJECTIVE: To identify intraoperative neurophysiologic measures predictive of delayed progressive sensorineural hearing loss in the operative ear after a middle fossa approach (MCF) for resection of vestibular schwannoma (VS). STUDY DESIGN: Retrospective review. SETTING: Academic, tertiary referral center. PATIENTS: Subjects with vestibular schwannoma who underwent a MCF microsurgical resection of VS were analyzed for individuals whose hearing was initially preserved but subsequently developed progressive sensorineural hearing loss in the operative ear. Thirty-seven patients were identified for whom audiologic and neurophysiologic data was available. INTERVENTION: Intraoperative neurophysiologic changes will correlate with delayed sensorineural hearing loss in the operative ear. MAIN OUTCOME MEASURES: Audiometric evaluations, intraoperative electrocochleography (ECoG), and auditory brainstem response (ABR) measures. RESULTS: Twenty-five subjects experienced stable hearing or hearing loss in the operative ear comparable to the contralateral ear. Twelve subjects suffered a significant increase in the hearing asymmetry between ears. Deterioration in the amplitude of wave V of the ABR persisting at the close of tumor resection correlated with delayed sensorineural hearing loss in the operative ear (p 0.02, 5% mean improvement in the stable hearing group, versus a 14% decline with progressive asymmetry), but changes in ECoG or other auditory brainstem response parameters (p > 0.05) were not predictive. CONCLUSIONS: Persisting amplitude reduction of wave V of the intraoperative ABR best correlates with delayed progressive sensorineural hearing loss in the operative ear. Neither persistent changes in ECoG, other ABR parameters, nor transient changes, correlated with delayed progressive sensorineural hearing loss in the operative ear.

Auditory Outcomes Following Transmastoid and Middle Cranial Fossa Approaches for Superior Semicircular Canal Dehiscence Repair.

OBJECTIVE: To describe postoperative hearing outcomes following transmastoid (TM) and middle cranial fossa (MCF) approaches for semicircular canal dehiscence (SSCD) repair. STUDY DESIGN: Retrospective review. SETTING: Academic, tertiary referral center. PATIENTS: Adults with SSCD who underwent repair between 2005 and 2019. INTERVENTIONS: Pure tone audiometry pre- and postoperatively after SSCD repair. MAIN OUTCOME MEASURES: Change in air-bone gap (ABG) at 250 and 500 Hz, pure tone average (PTA), bone conduction (BC), and air conduction (AC) thresholds at 500, 1000, 2000, and 4000 Hz for patients undergoing TM and MCF approaches for SSCD repair. RESULTS: The average change in BC PTA for patients undergoing TM (n = 26) and MCF (n = 24) SSCD repair was not significantly different between the two groups. The first and final postoperative PTAs were recorded an average of 1.7 (range 0.30-3.0) and 29.1 (range 3.5-154) months postoperatively. For patients who underwent MCF repair, the average BC PTAs increased (+) by 2.2 dB HL (p 0.43) and 0.57 dB HL (p 0.88) at the first and final audiograms respectively compared to +1.27 dB HL (p 0.53) and a decrease (-) of 0.57 dB HL (p 0.63) for the TM group. The average changes in low frequency ABG for patients undergoing MCF repair were -4.7 dB (p 0.08) and -6.9 dB (p 0.15) at first and final audiograms respectively compared to -4.9 dB (p 0.06) and -4.1 dB (p 0.36) for patients who underwent TM repair. There was a high frequency hearing loss noted at 8000 Hz for the MCF (30.0 dB ±â€Š18.7 preop; 41.7 dB ±â€Š21.7 postop; p 0.01) and TM (32.1 dB ±â€Š23.2 preop; 44.3 dB ±â€Š29.6 postop; p 0.001) groups which persisted on long term follow up. CONCLUSIONS: Both TM and MCF approaches to SSCD repair can be performed with long-term preservation of hearing. ABGs were reduced in each treatment group but did not reach significance. A high frequency hearing loss (8000 Hz) may be expected with either approach.