CTP (Cochlin-tomoprotein) detection in the profuse fluid leakage (gusher) from cochleostomy

Abstract

Conclusions: By testing 125 samples, we confirmed that Cochlin-tomoprotein (CTP) is present in the perilymph, not in cerebrospinal fluid (CSF). Perilymph and CSF exist in two distinct compartments, even in the case of a malformed inner ear with a bony defect in the lamina cribrosa, as described here. Cochleostomy might have suddenly decreased the perilymph pressure, allowing the influx of CSF into the inner ear resulting in profuse fluid leakage, first perilymph then CSF. Objectives: The first purpose of this study was to further confirm the specificity of the perilymph-specific protein CTP that we reported recently. Secondly, we assessed the nature of the fluid leakage from the cochleostomy using the CTP detection test. Methods: A standardized CTP detection test was performed on 65 perilymph and 60 CSF samples. Samples of profuse fluid leakage collected from cochleostomy during cochlear implantation surgery of one patient with branchio-oto-renal (BOR) syndrome were also tested by the CTP detection test. Results: CTP was detected in 60 of 65 perilymph samples but not in any of the CSF samples. The leaked fluid was shown to contain CTP, i.e. perilymph, at the outset, and then the CTP detection signals gradually disappeared as time elapsed.

Keywords::

• Perilymph
• CSF
• cochlear implant
• COCH gene
• Cochlin isoform
• branchio-oto-renal syndrome
• sensorineural hearing loss

Acknowledgments

We thank Dr S. Iwasaki, Hamamatu Redcross Hospital, Japan, for a critical review of the manuscript. This study was supported by Health and Labor Sciences Research Grants in Japan (Research on Measures for Intractable Diseases, Researches on Sensory and Communicative Disorders), a grant from the Ministry of Education, Culture, Sports, Science and Technology.

Declaration of interest: All authors hereby state that they have received no financial support and have no conflicts of interest that might bias their work.