Background: Perilymphatic fistula (PLF) is an abnormal connection between the inner and middle ear. A procedure for obtaining definite proof of a PLF remains elusive, and methods of diagnosis remain controversial. To date, there is no clinically relevant biochemical marker for perilymph leakage. Using proteomic analysis of inner ear proteins, we have previously found unique properties of cochlin, encoded by the COCH gene. We detected 3 cochlin isoforms (p63s, p44s and p40s) in the inner ear tissue and a short 16-kDa isoform of cochlin-tomoprotein (CTP) in the perilymph. Since cochlin was found to be highly specific to the inner ear, we speculated that CTP might also be specific to the perilymph. The aim of this study was to determine whether CTP, a novel perilymph-specific protein, could be used as a marker for the diagnosis of PLF. Methods: By Western blotting, we investigated the specificity of CTP expression in a range of body fluids that included perilymph, serum, saliva and cerebrospinal fluid. To elucidate the detection limit of CTP, serially diluted recombinant human (rh)CTP as well as human perilymph was tested. Results: CTP was selectively expressed in all 20 perilymph samples tested, but not in 77 samples of the other body fluids. The detection limit of rhCTP was 0.27 ng or 0.022 μl of perilymph per well on Western blot analysis. Conclusion: The results strongly suggest that CTP can be a specific marker of perilymph leakage. Moreover, CTP has the potential to be a biochemical marker that allows a definitive diagnosis of the etiology of PLF-related hearing loss and vestibular disorders.

1.
Abe S, Katagiri T, Saito-Hisaminato A, Usami S, Inoue Y, Tsunoda T, Nakamura Y: Identification of CRYM as a candidate responsible for nonsyndromic deafness, through cDNA microarray analysis of human cochlear and vestibular tissue. Am J Hum Genet 2003;72:73–82.
2.
Bachmann G, Petereit H, Djenabi U, Michel O: Predictive values of beta-trace protein (prostaglandin D synthase) by use of laser-nephelometry assay for the identification of cerebrospinal fluid. Neurosurgery 2002;50:571–576.
3.
Bassiouny M, Hirsch BE, Kelly RH, Kamerer DB, Cass SP: Beta 2 transferrin application in otology. Am J Otol 1992;13:552–555.
4.
Buchman CA, Luxford WM, Hirsch BE, Fucci MJ, Kelly RH: Beta-2 transferrin assay in the identification of perilymph. Am J Otol 1999;20:174–178.
5.
DePalma RG, Burris DG, Champion HR, Hodgson MJ: Blast injuries. N Engl J Med 2005;352:1335–1342.
6.
Fitzgerald DC: Head trauma: hearing loss and dizziness. J Trauma 1996;40:488–496.
7.
Fitzgerald DC: Perilymphatic fistula and Menière’s disease. Clinical series and literature review. Ann Otol Rhinol Laryngol 2001;110:430–436.
8.
Friedland DR, Wackym PA: A critical appraisal of spontaneous perilymphatic fistulas of the inner ear. Am J Otol 1999;20:261–276.
9.
Gehrking E, Wisst F, Remmert S, Sommer K: Intraoperative assessment of perilymphatic fistulas with intrathecal administration of fluorescein. Laryngoscope 2002;112:1614–1618.
10.
Goodhill V: Sudden deafness and round window rupture. Laryngoscope 1971;81:1462–1474.
11.
Hughes GB, Sismanis A, House JW: Is there consensus in perilymph fistula management? Otolaryngol Head Neck Surg 1990;102:111–117.
12.
Ikezono T, Omori A, Ichinose S, Pawankar R, Watanabe A, Yagi T: Identification of the protein product of the Coch gene – hereditary deafness gene – as the major component of bovine inner ear protein. Biochim Biophys Acta 2001;3:258–265.
13.
Ikezono T, Shindo S, Li L, Omori A, Ichinose S, Watanabe A, Kobayashi T, Pawankar R, Yagi T: Identification of a novel Cochlin isoform in the perilymph: insights to Cochlin function and the pathogenesis of DFNA9. Biochem Biophys Res Commun 2004;6:440–446.
14.
Jackler RK, Brackmann DE: Neurotology, ed 2. Philadelphia, Mosby, 2005, pp 247–249.
15.
Jackler RK, Luxford WM, House WF: Congenital malformations of the inner ear: a classification based on embryogenesis. Laryngoscope 1987;97(suppl 40):2–14.
16.
Klingmann C, Praetorius M, Baumann I, Plinkert PK: Barotrauma and decompression illness of the inner ear: 46 cases during treatment and follow-up. Otol Neurotol 2007;28:447–454.
17.
Kohut RI, Hinojosa R, Budetti JA: Perilymphatic fistula: a histopathologic study. Ann Otol Rhinol Laryngol 1986;95:466–471.
18.
Kommareddi K, Nair S, Raphael Y, Telian A, Kim H, Arts A, El-Kashlan K, Carey E: Cochlin isoforms and their interaction with CTL2 (SLC44A2) in the inner ear. J Assoc Res Otolaryngol 2007;8:435–446.
19.
Levenson MJ, Desloge RB, Parisier SC: Beta-2 transferrin: limitations of use as a clinical marker for perilymph. Laryngoscope 1996;106:159–161.
20.
Li L, Ikezono T, Watanabe A, Shindo S, Pawankar R, Yagi T: Expression of full-length Cochlin p63s is inner ear specific. Auris Nasus Larynx 2005;32:219–223.
21.
Maitland CG: Perilymphatic fistula. Curr Neurol Neurosci Rep 2001;1:486–491.
22.
Mata AD, Marques D, Rocha S, Francisco H, Santos C, Mesquita MF, Singh J: Effects of diabetes mellitus on salivary secretion and its composition in the human. Mol Cell Biochem 2004;261:137–142.
23.
Minor LB: Labyrinthine fistulae: pathobiology and management. Curr Opin Otolaryngol Head Neck Surg 2003;11:340–346.
24.
Mizuta K, Ikezono T, Iwasaki S, Arai M, Hashimoto Y, Pawankar R, Watanabe T, Shindo S, Mineta H: Ultrastructural co-localization of cochlin and type II collagen in the rat semicircular canal. Neurosci Lett 2008;434:104–107.
25.
Nomura Y: Perilymph fistula: concept, diagnosis and management. Acta Otolaryngol Suppl 1994;514:52–54.
26.
Olaf M, Hela P, Eckart K, Leif E, Gregor B: First clinical experience with beta-trace protein (prostaglandin D synthase) as a marker for perilymphatic fistula. J Laryngol Otol 2005;119:765–769.
27.
Olaf M, Stephan B, Marko N, Gregor B: Beta-trace protein (prostaglandin D synthase): a stable and reliable protein in perilymph. GMS Ger Med Sci 2005;3:1–9.
28.
Poe DS, Gadre AK, Rebeiz EE, Pankratov MM: Intravenous fluorescein for detection of perilymphatic fistulas. Am J Otol 1993;14:51–54.
29.
Rauch SD: Transferrin microheterogeneity in human perilymph. Laryngoscope 2000;110:545–552.
30.
Reilly JS: Congenital perilymphatic fistula: a prospective study in infants and children. Laryngoscope 1989;99:393–397.
31.
Risch L, Lisec I, Jutzi M, Podvinec M, Landolt H, Huber AR: Rapid, accurate and non-invasive detection of cerebrospinal fluid leakage using combined determination of beta-trace protein in secretion and serum. Clin Chim Acta 2005;351:169–176.
32.
Robertson NG, Cremers CW, Huygen PL, Ikezono T, Krastins B, Kremer H, Kuo SF, Liberman MC, Merchant SN, Miller CE, Nadol JB, Sarracino DA, Verhagen WI, Morton CC: Cochlin immunostaining of inner ear pathologic deposits and proteomic analysis in DFNA9 deafness and vestibular dysfunction. Hum Mol Genet 2006;15:1071–1085.
33.
Robertson NG, Khetarpal U, Gutierrez-Espeleta GA, Bieber FR, Morton CC: Isolation of novel and known genes from a human fetal cochlear cDNA library using subtractive hybridization and differential screening. Genomics 1994;23:42–50.
34.
Robertson NG, Lu L, Heller S, Merchant SN, Eavey RD, McKenna M, Nadol JB, Miyamoto RT, Linthicum FH, Lubianca Neto JF, Hudspeth AJ, Seidman CE, Morton CC, Seidman JG: Mutations in a novel cochlear gene cause DFNA9, a human nonsyndromic deafness with vestibular dysfunction. Nat Genet 1998;20:299–303.
35.
Schuknecht HF: Mechanism of inner ear injury from blows to the head. Ann Otol Rhinol Laryngol 1969;78:253–262.
36.
Schuknecht HF: Myths in neurotology. Am J Otol 1992;13:124–126.
37.
Shea JJ Jr: Complications of the Stapedectomy Operation. Ann Otol Rhinol Laryngol 1963;72:1108–1123.
38.
Shindo S, Ikezono T, Ishizaki M, Sekiguchi S, Mizuta K, Li L, Takumida M, Pawankar R, Yagi T: Spatiotemporal expression of cochlin in the inner ear of rats during postnatal development. Neurosci Lett 2008;444:148–152.
39.
Strohm M: Trauma of the middle ear. Clinical findings, postmortem observations and results of experimental studies. Adv Otorhinolaryngol 1986;35:1–254.
40.
Thalmann I, Kohut RI, Ryu J, Comegys TH, Senarita M, Thalmann R: Protein profile of human perilymph: in search of markers for the diagnosis of perilymph fistula and other inner ear disease. Otolaryngol Head Neck Surg 1994;111:273–280.
41.
Weber PC, Kelly RH, Bluestone CD, Bassiouny M: Beta 2-transferrin confirms perilymphatic fistula in children. Otolaryngol Head Neck Surg 1994;110:381–386.
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