Blood levels of the inner ear protein prestine rise significantly in patients experiencing tinnitus, according to an American study published in Otolaryngology-Head and Neck Surgery.
Physicians Patrick Adamczyk and Kourosh Parham of the University of Connecticut described the finding, which helps address a condition that currently relies entirely on patient descriptions, Science et vie reported. Approximately one in ten people live with tinnitus, a perception of sound in the ears without an external source.
To test whether internal proteins could serve as indicators, the research team recruited 82 adults. Half of the participants lived with tinnitus in both ears for several months, while the control group did not. Researchers measured four inner ear proteins in their serum: prestine, otoferlin, connexin 26, and stereocilin.
Only prestine separated the two groups during the analysis. Serum levels of prestine proved notably superior in patients with tinnitus, reaching statistical significance. The average gap reached approximately 330 picogrammes per millilitre, with levels climbing by about 50 percent in affected individuals.
Age, hearing loss, and noise exposure did not explain the discrepancy. The divergence persisted after researchers adjusted for those three factors. The authors also measured a correlation between prestine and stereocilin, which appeared even more marked in the tinnitus group.
Prestine drives the vibration of outer hair cells, the specialized cells in the cochlea that amplify soft sounds. When these cells suffer damage or distress, the protein apparently leaks out of the inner ear and enters the bloodstream. Despite this physiological link, a simple blood draw does not yet suffice to establish a clinical diagnosis.
The observed correlation does not automatically yield a functioning diagnostic test. Diagnostic precision analysis disappointed the investigators, as no specific prestine threshold cleanly separated a patient from a control subject in the sample.
The authors said that certain cases of tinnitus originate in the brain rather than the cochlea. A cochlear biomarker remains undetectable in individuals whose perception stems from neural pathways instead of sensory hair cell degradation. Prestige levels do not scale with symptom severity, meaning a severely distressed person does not necessarily exhibit higher protein counts than someone with mild perception.
Most volunteers in the cohort reported mild tinnitus, which limits the broader application of the current results. The protein also appears in other bodily tissues, including the heart, making its exact origin in blood samples uncertain. The researcher who developed the assay holds a patent on the dosage, viewing the work as a proof of concept rather than a ready tool for routine clinical practice.
- What was found: Blood tests showed higher levels of the inner ear protein prestine in people with tinnitus.
- Why it’s not a test yet: Prestine levels overlap between groups, and some tinnitus originates in the brain rather than the ear, rendering the marker invisible for those patients.
- Current status: The assay exists only within research protocols, and no commercial laboratory offers this blood test to patients.
Previous work by the same team on a separate cohort pointed toward prestine, but both sets of results require confirmation across larger sample sizes. Subsequent research will focus on patients presenting with severe or recent-onset tinnitus, categories absent from the American sample. Investigators also intend to pinpoint the exact biological origin of the measured prestine.
