Dataset Information

Impact of Systemic versus Intratympanic Dexamethasone Administration on the Perilymph Proteome.

ABSTRACT: Glucocorticoids are the first-line treatment for sensorineural hearing loss, but little is known about the mechanism of their protective effect or the impact of route of administration. The recent development of hollow microneedles enables safe and reliable sampling of perilymph for proteomic analysis. Using these microneedles, we investigate the effect of intratympanic (IT) versus intraperitoneal (IP) dexamethasone administration on guinea pig perilymph proteome. Guinea pigs were treated with IT dexamethasone (n = 6), IP dexamethasone (n = 8), or untreated for control (n = 8) 6 h prior to aspiration. The round window membrane (RWM) was accessed via a postauricular approach, and hollow microneedles were used to perforate the RWM and aspirate 1 μL of perilymph. Perilymph samples were analyzed by liquid chromatography-mass spectrometry-based label-free quantitative proteomics. Mass spectrometry raw data files have been deposited in an international public repository (MassIVE proteomics repository at https://massive.ucsd.edu/) under data set # MSV000086887. In the 22 samples of perilymph analyzed, 632 proteins were detected, including the inner ear protein cochlin, a perilymph marker. Of these, 14 proteins were modulated by IP, and three proteins were modulated by IT dexamethasone. In both IP and IT dexamethasone groups, VGF nerve growth factor inducible was significantly upregulated compared to control. The remaining adjusted proteins modulate neurons, inflammation, or protein synthesis. Proteome analysis facilitated by the use of hollow microneedles shows that route of dexamethasone administration impacts changes seen in perilymph proteome. Compared to IT administration, the IP route was associated with greater changes in protein expression, including proteins involved in neuroprotection, inflammatory pathway, and protein synthesis. Our findings show that microneedles can mediate safe and effective intracochlear sampling and hold promise for inner ear diagnostics.

SUBMITTER: Szeto B

PROVIDER: S-EPMC8663798 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:ImportanceThe use of intratympanically applied steroids is of increasing interest. Consequently, research has focused on finding an ideal drug that diffuses through the round window membrane and can be retained in the perilymph.ObjectiveTo compare levels of triamcinolone acetonide (TAC) in perilymph and plasma after intratympanic injection.Design, setting, and participantsThis randomized clinical trial included 40 patients receiving cochlear implants at a single tertiary care center in Vienna, Austria. Patients were randomized to 1 of 4 treatment groups receiving 1 of 2 intratympanic doses of TAC (10 mg/mL or 40 mg/mL) at 1 of 2 approximate time points (24 hours or 1 hour) before sampling the perilymph. Inclusion was carried out between November 2017 and January 2020, and data were analyzed in December 2020.InterventionsAll patients underwent intratympanic injection of TAC. During cochlear implantation, perilymph and plasma were sampled for further analysis.Main outcomes and measuresLevels of TAC measured in perilymph and plasma.ResultsAmong the 37 patients (median [range] age, 57 [26-88] years; 18 [49%] men) included in the analysis, TAC was present at a median (range) level of 796.0 (46.4-7706.7) ng/mL. In the majority of patients (n = 29; 78%), no drug was detectable in the plasma after intratympanic injection. Levels above the limit of detection were less than 2.5 ng/mL. The 1-factorial analysis of variance model showed lower TAC levels in the group that received TAC, 10 mg/mL, 24 hours before surgery (median, 271 ng/mL) compared with the group that received TAC, 10 mg/mL, 1 hour before surgery (median, 2877 ng/mL), as well as in comparison with the groups receiving TAC, 40 mg/mL, 24 hours before surgery (median, 2150 ng/mL) and 1 hour before surgery (median, 939 ng/mL). The 2-factorial analysis of variance model showed lower TAC levels in the group receiving TAC, 10 mg/mL, 24 hours before surgery than the group receiving TAC, 10 mg/mL, 1 hour before surgery, and higher TAC levels in the group receiving TAC, 40 mg/mL, 24 hours before surgery compared with the group receiving TAC, 10 mg/mL, 24 hours before surgery. Patients with thickening of the middle ear had statistically significantly higher plasma levels (median, 1.4 ng/mL vs 0 ng/mL) and lower perilymph levels (median, 213.1 ng/mL vs 904 ng/mL) than individuals with unremarkable middle ear mucosa.Conclusions and relevanceIn this randomized clinical trial, TAC was shown to be a promising drug for intratympanic therapies, with similar levels in perilymph 1 hour and 24 hours after injection (distinctly in the groups receiving the 40 mg/mL dose). There was also minimal dissemination to the plasma, especially in patients with unremarkable middle ear mucosa.Trial registrationClinicalTrials.gov Identifier: NCT03248856.

Project description:BACKGROUND:Due to the surrounding bone, the human inner ear is relatively inaccessible and difficult to reach for cellular and molecular analyses. However, these types of investigations are needed to better understand the etiology, pathophysiology and progression of several inner ear disorders. Moreover, the fluid from the inner ear cannot be sampled for micro-chemical analyses from healthy individuals in vivo. Therefore, in the present paper, we studied patients with vestibular schwannoma (VS) undergoing trans-labyrinthine surgery (TLS). Our primary aim was to identify perilymph proteins in patients with VS on an individual level. Our second aim was to investigate the proteins identified at a functional level and our final aim was to search for biological markers for tumor-associated hearing loss and tumor diameter. METHODS AND FINDINGS:Sixteen patients underwent TLS for sporadic VS. Perilymph was aspirated through the round window before opening the labyrinth. One sample was contaminated and excluded resulting in 15 usable samples. Perilymph samples were analyzed with an online tandem LTQ-Orbitrap mass spectrometer. Data were analyzed with MaxQuant software to identify the total number of proteins and to quantify proteins in individual samples. Protein function was analyzed using the PANTHER Overrepresentation tool. Associations between perilymph protein content, clinical parameters, tumor-associated hearing loss and tumor diameter were assessed using Random Forest and Boruta. In total, 314 proteins were identified; 60 in all 15 patients and 130 proteins only once in 15 patients. Ninety-one proteins were detected in at least 12 out of 15 patients. Random Forest followed by Boruta analysis confirmed that alpha-2-HS-glycoprotein (P02765) was an independent variable for tumor-associated hearing loss. In addition, functional analysis showed that numerous processes were significantly increased in the perilymph. The top three enriched biological processes were: 1) secondary metabolic processes; 2) complement activation and 3) cell recognition. CONCLUSIONS:The proteome of perilymph in patients with vestibular schwannoma has an inter-individual stable section. However, even in a cohort with homogenous disease, the variation between individuals represented the majority of the detected proteins. Alpha-2-HS-glycoprotein, P02765, was shown to be an independent variable for tumor-associated hearing loss, a finding that needs to be verified in other studies. In pathway analysis perilymph had highly enriched functions, particularly in terms of increased immune and metabolic processes.

Dataset Information

Impact of Systemic versus Intratympanic Dexamethasone Administration on the Perilymph Proteome.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets