Pathophysiology of the inner ear after blast injury caused by laser-induced shock wave

Niwa, Katsuki; Mizutari, Kunio; Matsui, Toshiyasu; Kurioka, Takaomi; Matsunobu, Takeshi; Kawauchi, Satoko; Satoh, Yasushi; Sato, Shunichi; Shiotani, Akiko; Kobayashi, Yasushi

doi:10.1038/srep31754

Cited by 44 publications

(57 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The outer hair cells of the cochlea play an important role in tinnitus [32] . Otoacoustic emissions correspond closely to the physiological state of outer hair cells of the cochlea and allow for a noninvasive, rapid, and cost-effective measure of presynaptic auditory function; it is also a useful audiological method for evaluating patients complaining of tinnitus.…”

Section: Discussionmentioning

confidence: 99%

Effects of oral zinc supplementation on patients with noise-induced hearing loss associated tinnitus: A clinical trial

et al. 2019

View full text Add to dashboard Cite

Background Zinc plays a vital antioxidant role in human metabolism. Recent studies have demonstrated a correlation between noise-induced hearing loss (NIHL) and oxidative injury; however, no investigation has focused specifically on the subgroup of NIHL associated tinnitus patients. We aimed to evaluate the effectiveness of zinc supplementation in treating NIHL associated tinnitus. Methods Twenty patients with tinnitus and a typical NIHL audiogram (38 ears) were included in this study. Another 20 healthy subjects were used as the control group. A full medical history assessment was performed, and each subject underwent an otoscopic examination, basic audiologic evaluation, distortion product otoacoustic emissions (DPOAEs), tinnitus-match testing, Tinnitus Handicap Inventory (THI) and serum zinc level analyses. After 2 months of treatment with zinc, all tests were repeated. Results There was a significant difference between pretreatment and post-treatment within the tinnitus group (73.6 vs. 84.6 μg/dl). The pre- and post-treatment difference in serum zinc was significantly higher in the young group (≦50 years) compared to the old group (19.4 ± 11.4 vs. 2.6 ± 9.2 μg/dl, respectively; p = 0.002). There were no statistically significant differences in hearing thresholds, speech reception thresholds, or tinnitus frequency and loudness results before and after treatment. In addition, 17 patients (85%) showed statistically significant improvement of THI-total scores post-treatment, from 38.3 to 30 ( p = 0.024). Conclusions Zinc oral supplementation elevated serum zinc levels, especially in younger patients. THI scores improved significantly following zinc treatment in patients with NIHL associated tinnitus. However, no improvements in objective hearing parameters were observed.

show abstract

Section: Discussionmentioning

confidence: 99%

Effects of oral zinc supplementation on patients with noise-induced hearing loss associated tinnitus: A clinical trial

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Recent work showing that synaptopathy also occurs after a single high-intensity shockwave 43 suggests that prolonged overexposure of the post-synaptic membrane to glutamate may not be required. Furthermore, it is unclear whether noise-induced, age-related, and drug-induced synaptopathy all share the same mechanism.…”

Section: Cochlear Synaptopathy In Nihl and Ahlmentioning

confidence: 99%

Noise-induced and age-related hearing loss: new perspectives and potential therapies

2017

View full text Add to dashboard Cite

The classic view of sensorineural hearing loss has been that the primary damage targets are hair cells and that auditory nerve loss is typically secondary to hair cell degeneration. Recent work has challenged that view. In noise-induced hearing loss, exposures causing only reversible threshold shifts (and no hair cell loss) nevertheless cause permanent loss of >50% of the synaptic connections between hair cells and the auditory nerve. Similarly, in age-related hearing loss, degeneration of cochlear synapses precedes both hair cell loss and threshold elevation. This primary neural degeneration has remained a “hidden hearing loss” for two reasons: 1) the neuronal cell bodies survive for years despite loss of synaptic connection with hair cells, and 2) the degeneration is selective for auditory nerve fibers with high thresholds. Although not required for threshold detection when quiet, these high-threshold fibers are critical for hearing in noisy environments. Research suggests that primary neural degeneration is an important contributor to the perceptual handicap in sensorineural hearing loss, and it may be key to the generation of tinnitus and other associated perceptual anomalies. In cases where the hair cells survive, neurotrophin therapies can elicit neurite outgrowth from surviving auditory neurons and re-establishment of their peripheral synapses; thus, treatments may be on the horizon.

show abstract

“…We have been using a laser-induced shock wave (LISW) to investigate the pathophysiology and mechanism of bTBI. [5][6][7][8][9][10] The advantages of the use of an LISW for bTBI research include its safety, ease in handling, and ability to precisely control the shock wave energy and size. In addition, the confined nature of the shock wave energy of an LISW enables site-specific or targeted application to animals, which is useful because blast injuries resulting from systemic blast exposure are often too complex to analyze or understand the mechanism of injuries.…”

Section: Introductionmentioning

confidence: 99%

Multispectral imaging of cortical vascular and hemodynamic responses to a shock wave: observation of spreading depolarization and oxygen supply-demand mismatch

et al. 2019

Self Cite

View full text Add to dashboard Cite

imaging of cortical vascular and hemodynamic responses to a shock wave: observation of spreading depolarization and oxygen supply-demand mismatch," J.Abstract. Blast-induced traumatic brain injury has been a recent major concern in neurotraumatology.However, its pathophysiology and mechanism are not understood partly due to insufficient information on the brain pathophysiology during/immediately after shock wave exposure. We transcranially applied a laserinduced shock wave (LISW, ∼19 Pa · s) to the left frontal region in a rat and performed multispectral imaging of the ipsilateral cortex through a cranial window (n ¼ 4). For the spectral data obtained, we conducted multiple regression analysis aided by Monte Carlo simulation to evaluate vascular diameters, regional hemoglobin concentration (rC Hb ), tissue oxygen saturation (StO 2 ), oxygen extraction fraction, and light-scattering signals as a signature of cortical spreading depolarization (CSD). Immediately after LISW exposure, rC Hb and StO 2 were significantly decreased with distinct venular constriction. CSD was then generated and was accompanied by distinct hyperemia/hyperoxemia. This was followed by oligemia with arteriolar constriction, but it soon recovered (within ∼20 min). However, severe hypoxemia was persistently observed during the post-CSD period (∼1 h). These observations indicate that inadequate oxygen supply and/or excessive oxygen consumption continued even after blood supply was restored in the cortex. Such a hypoxemic state and/or a hypermetabolic state might be associated with brain damage caused by a shock wave.

show abstract

Pathophysiology of the inner ear after blast injury caused by laser-induced shock wave

Cited by 44 publications

References 41 publications

Effects of oral zinc supplementation on patients with noise-induced hearing loss associated tinnitus: A clinical trial

Effects of oral zinc supplementation on patients with noise-induced hearing loss associated tinnitus: A clinical trial

Noise-induced and age-related hearing loss: new perspectives and potential therapies

Multispectral imaging of cortical vascular and hemodynamic responses to a shock wave: observation of spreading depolarization and oxygen supply-demand mismatch

Contact Info

Product

Resources

About