Proteome Analysis of Human Perilymph Using an Intraoperative Sampling Method

The knowledge about
the etiology and pathophysiology of sensorineural
hearing loss (SNHL) is still very limited. This study aims at the
improvement of understanding different types of SNHL by proteome analysis
of human perilymph. Sampling of perilymph was established during inner
ear surgeries (cochlear implantation, vestibular schwannoma surgeries),
and safety of the sampling method was determined by checking hearing
threshold with pure-tone audiometry postoperatively. An in-depth shot-gun
proteomics approach was performed to identify cochlear proteins and
the individual proteome in perilymph of patients. This method enables
the identification and quantification of protein composition of perilymph.
The proteome of 41 collected perilymph samples with volumes of 1–12
μL was analyzed by data-dependent acquisition, resulting in
overall 878 detected protein groups. At least 203 protein groups were
solely identified in perilymph, not in reference samples (serum, cerebrospinal
fluid), displaying a specific protein pattern for perilymph. Samples
were grouped by patient’s age and surgery type, leading to
the identification of some proteins specific to particular subgroups.
Proteins with different abundances between different sample groups
were subjected to classification by gene ontology annotations. The
identified proteins might serve as biomarkers to develop tools for
noninvasive inner ear diagnostics and to elucidate molecular profiles
of SNHL.