Development of Chinese herbal medicine for sensorineural hearing loss

According to the World Health Organization's world report on hearing, nearly 2.5 billion people worldwide will suffer from hearing loss by 2050, which may contribute to a severe impact on individual life quality and national economies. Sensorineural hearing loss (SNHL) occurs commonly as a result of noise exposure, aging, and ototoxic drugs, and is pathologically characterized by the impairment of mechanosensory hair cells of the inner ear, which is mainly triggered by reactive oxygen species accumulation, inflammation, and mitochondrial dysfunction. Though recent advances have been made in understanding the ability of cochlear repair and regeneration, there are still no effective therapeutic drugs for SNHL. Chinese herbal medicine which is widely distributed and easily accessible in China has demonstrated a unique curative effect against SNHL with higher safety and lower cost compared with Western medicine. Herein we present trends in research for Chinese herbal medicine for the treatment of SNHL, and elucidate their molecular mechanisms of action, to pave the way for further research and development of novel effective drugs in this field.

Ototoxicidad y factores predisponentes / Ototoxicity and predisposing factors

Introducción: la pérdida auditiva inducida por fármacos ototóxicos se consideró un problema grave, frecuente, con repercusión en el quehacer diario de otorrinolaringólogos y pediatras. Se documentó ototoxicidad relacionada con aminoglucósidos y tratamientos antineoplásicos, salicilatos, quininas y algunos diuréticos. Objetivo: profundizar en los enfoques actuales más novedosos sobre ototoxicidad, factores de riesgo, predisposición genética y prevención. Métodos: estudio retrospectivo de la literatura escrita en idiomas español e inglés, de los reportes más interesantes y sugerentes publicados, sin límite de tiempo anterior, hasta Febrero de 2017, a través de búsqueda en línea por Internet, y bases de datos consultadas: Google, Cochrane y PubMed-Medline. Desarrollo: se obtuvo un total de más de 100 artículos. Los mecanismos exactos de ototoxicidad por aminoglucósidos y cisplatino, constituyeron un área activa de investigación. Se analizó la relación entre ototoxicidad y las caspasas 8,9 y 3, mediadores esenciales en la apoptosis de células ciliadas en la cóclea y la hipoacusia. Se describió la relación entre las mutaciones del gen MTRNR1, que codifica para la subunidad ribosomal 12s, y la pérdida auditiva por ototoxicidad. Se relacionó con hipoacusia y sordera mitocondrial no sindrómica, transmisión exclusivamente materna, e incremento en la susceptibilidad a la ototoxicidad por aminoglucósidos, factor clave predisponente. Consideraciones finales: los fármacos ototóxicos, inducen toxicidad coclear e hipoacusia bilateralmente simétrica, o asimétrica, en altas frecuencias, secundaria a destrucción irreversible de células ciliadas externas en el órgano de Corti. Nuevas investigaciones sobre cisplatino identifican la población susceptible, y pueden ofrecer alternativas de tratamiento menos agresivas. Se abordan criterios actuales sobre monitoreo audiológico y grados de ototoxicidad. La prevención implica una estricta (AU)

Introduction: hearing loss induced by ototoxic drugs was approached as a serious, frequent problem with an impact on the daily work of otolaryngologists and pediatricians. A review was conducted about the relationship of ototoxicity to aminoglycosides, antineoplastic treatments, salicylates, quinines and some diuretics. Objective: analyze the most updated current approaches about ototoxicity, risk factors, genetic predisposition and prevention. Methods: a retrospective review was conducted of the literature on the topic published in Spanish and English, as well as the most interesting and thought-provoking reports, from an open start date until February 2017, by means of a search on the Internet and in the databases Google, Cochrane and PubMed-MEDLINE. Results: more than 100 papers were obtained. The exact ototoxicity mechanisms by aminoglycosides and cisplatin were an area of active research. An analysis was made of the relationship between ototoxicity and caspases 8, 9 and 3, essential mediators in the apoptosis of ciliated cells in the cochlea, and hearing loss. A description is provided of the relationship between mutations of the MTRNR1 gene, which codifies for the ribosomal subunit 12s, and hearing loss by ototoxicity. A connection was established with hearing loss and mitochondrial nonsyndromic deafness, exclusively maternal transmission, and increased susceptibility to ototoxicity by aminoglycosides, a key predisposing factor. Final considerations: ototoxic drugs induce cochlear toxicity and bilaterally symmetric or asymmetric hearing loss at high frequencies, secondary to irreversible destruction of external ciliated cells in the organ of Corti. Recent research about cisplatin has identified the susceptible population, and may offer new, less aggressive treatment alternatives. Current criteria are presented about audiological surveillance and ototoxicity grades. Prevention implies strict surveillance(AU)