Cisplatin-induced Ototoxicity Research Articles

N-acetylcysteine microparticles reduce cisplatin-induced RSC96 Schwann cell toxicity.

Cisplatin is known to cause inner ear dysfunction. There is growing evidence that cisplatin-induced demyelination of spiral or Scarpa's ganglion neurons may play an additional role in drug-induced ototoxicity alongside afferent neuron injury. As Schwann cells produce myelin, there may be an opportunity to reduce ototoxic inner ear damage by promoting Schwann cell viability. This work describes a cellular model of cisplatin-induced Schwann cell injury and investigates the ability of the antioxidant N-acetylcysteine to promote Schwann cell viability. A local delivery system of drug-eluting microparticles was then fabricated, characterized, and investigated for bioactivity. RSC96 rat Schwann cells were dosed with varying concentrations of cisplatin to obtain a dose curve and identify the lethal concentration of 50% of the cells (LC50). In subsequent experiments, RSC96 cells were co-treated with cisplatin and both resuspended or eluted N-acetylcysteine. Cell viability was assessed with the CCK8 assay. The LC50 dose of cisplatin was determined to be 3.76 μM (p = 2.2 x 10-16). When co-dosed with cisplatin and a therapeutic concentration of resuspended or eluted N-acetylcysteine, Schwann cells had an increased viability compared to cells dosed with cisplatin alone. RSC96 Schwann cell injury following cisplatin insult is characterized in this in vitro model. Cisplatin caused injury at physiologic concentrations and N-acetylcysteine improved cell viability and mitigated this injury. N-acetylcysteine was packaged into microparticles and eluted N-acetylcysteine retained its ability to increase cell viability, thus demonstrating promise as a therapeutic to offset cisplatin-induced ototoxicity. N/A Laryngoscope, 2023.

Fluoxetine, fluvoxamine, and hearing loss or tinnitus after cisplatin treatment: A retrospective cohort study.

Cisplatin use is often limited by its ototoxic side effects, which can lead to irreversible hearing loss. Preventing cisplatin-induced ototoxicity is crucial to improve patient outcomes. Fluoxetine and fluvoxamine, both selective serotonin reuptake inhibitors antidepressants, inhibit the NLR pyrin domain-containing protein 3 inflammasome, a potential therapeutic target for preventing ototoxicity. However, human studies have not evaluated if these antidepressants may protect against cisplatin-induced ototoxicity. The object of this study is to assess the association between fluoxetine or fluvoxamine use and incidence of hearing loss or tinnitus in a large cohort of patients receiving cisplatin chemotherapy. We use a retrospective cohort study within the U.S. Department of Veterans Affairs healthcare system. Adult patients with cancer who received cisplatin chemotherapy between 2000 and 2023 are included. Incidence of ototoxicity, defined by international classification of diseases revision 9-CM or international classification of diseases revision 10-CM diagnoses of hearing loss or tinnitus is compared between concurrent use of fluoxetine or fluvoxamine and cisplatin alone. A total of 20,552 patients were included. Of those, 489 received cisplatin and fluoxetine or fluvoxamine. After propensity score adjustment, the hazard of ototoxicity was lower in the group receiving fluoxetine or fluvoxamine compared to the group receiving cisplatin alone (HR = 0.62, 95% CI = (0.41-0.94)). Fluoxetine or fluvoxamine use may be associated with a reduced risk of cisplatin-induced ototoxicity. Randomized clinical trials are needed to confirm these findings and establish the efficacy of the medications in ototoxicity prevention. Further research is also warranted to investigate the potential mechanisms underlying this protective effect.

Susceptibility of mouse cochlear hair cells to cisplatin ototoxicity largely depends on sensory mechanoelectrical transduction channels both Ex Vivo and In Vivo

Cisplatin, a highly effective chemotherapeutic drug for various human cancers, induces irreversible sensorineural hearing loss as a side effect. Currently there are no highly effective clinical strategies for the prevention of cisplatin-induced ototoxicity. Previous studies have indicated that short-term cisplatin ototoxicity primarily affects the outer hair cells of the cochlea. Therefore, preventing the entry of cisplatin into hair cells may be a promising strategy to prevent cisplatin ototoxicity. This study aimed to investigate the entry route of cisplatin into mouse cochlear hair cells. The competitive inhibitor of organic cation transporter 2 (OCT2), cimetidine, and the sensory mechanoelectrical transduction (MET) channel blocker benzamil, demonstrated a protective effect against cisplatin toxicity in hair cells in cochlear explants. Sensory MET-deficient hair cells explanted from Tmc1Δ;Tmc2Δ mice were resistant to cisplatin toxicity. Cimetidine showed an additive protective effect against cisplatin toxicity in sensory MET-deficient hair cells. However, in the apical turn, cimetidine, benzamil, or genetic ablation of sensory MET channels showed limited protective effects, implying the presence of other entry routes for cisplatin to enter the hair cells in the apical turn. Systemic administration of cimetidine failed to protect cochlear hair cells from ototoxicity caused by systemically administered cisplatin. Notably, outer hair cells in MET-deficient mice exhibited no apparent deterioration after systemic administration of cisplatin, whereas the outer hair cells in wild-type mice showed remarkable deterioration. The susceptibility of mouse cochlear hair cells to cisplatin ototoxicity largely depends on the sensory MET channel both ex vivo and in vivo. This result justifies the development of new pharmaceuticals, such as a specific antagonists for sensory MET channels or custom-designed cisplatin analogs which are impermeable to sensory MET channels.

Comparison of Intratympanic Oxytocin and Dexamethasone in Cisplatin Ototoxicity: An Experimental Study.

Although it is widely used, there is still no valid treatment for ototoxicity caused by the antineoplastic drug cisplatin. In this study, we aimed to investigate the efficacy of intratympanic resveratrol and intratympanic dexamethasone treatment in cisplatin-induced ototoxicity. We also compared intratympanic atosiban (oxytocin antagonist) and oxytocin in cisplatin ototoxicity. In this study, 30 rats (60 ears) were used by separating into 5 groups. Cisplatin, oxytocin, dexamethasone, atosiban and 0.9% NaCl were administered intraperitoneally to all groups separately. Auditory Brainstem Response and Distortion Product Otoacoustic Emission tests were performed on all groups before and 72h after the procedure. Pre-treatment values were higher than post-treatment values in all groups (p < 0.001). There was no significant prolongation of the post-treatment Auditory Brainstem Response I-IV interval in the oxytocin and dexamethasone groups (p > 0.05). There was no significant decrease in the frequencies of 2832 and 4004 after treatment in the oxytocin and dexamethasone group compared to pre-treatment in Distortion Product Otoacoustic Emission. As a result, it has been shown that intratympanic oxytocin may be an option that can be used in the treatment, although it is not as effective as dexamethasone in preventing cisplatin ototoxicity.

Nobiletin alleviates cisplatin-induced ototoxicity via activating autophagy and inhibiting NRF2/GPX4-mediated ferroptosis

Nobiletin, a citrus polymethoxy flavonoid with antiapoptotic and antioxidative properties, could safeguard against cisplatin-induced nephrotoxicity and neurotoxicity. Cisplatin, as the pioneer of anti-cancer drug, the severe ototoxicity limits its clinical applications, while the effect of nobiletin on cisplatin-induced ototoxicity has not been identified. The current study investigated the alleviating effect of nobiletin on cisplatin-induced ototoxicity and the underlying mechanisms. Apoptosis and ROS formation were evaluated using the CCK-8 assay, Western blotting, and immunofluorescence, indicating that nobiletin attenuated cisplatin-induced apoptosis and oxidative stress. LC3B and SQSTM1/p62 were determined by Western blotting, qPCR, and immunofluorescence, indicating that nobiletin significantly activated autophagy. Nobiletin promoted the nuclear translocation of NRF2 and the transcription of its target genes, including Hmox1, Nqo1, and ferroptosis markers (Gpx4, Slc7a11, Fth, and Ftl), thereby inhibiting ferroptosis. Furthermore, RNA sequencing analysis verified that autophagy, ferroptosis, and the NRF2 signaling pathway served as crucial points for the protection of nobiletin against ototoxicity caused by cisplatin. Collectively, these results indicated, for the first time, that nobiletin alleviated cisplatin-elicited ototoxicity through suppressing apoptosis and oxidative stress, which were attributed to the activation of autophagy and the inhibition of NRF2/GPX4-mediated ferroptosis. Our study suggested that nobiletin could be a prospective agent for preventing cisplatin-induced hearing loss.

Combined genetic polymorphisms of the GSTT1 and NRF2 genes increase susceptibility to cisplatin-induced ototoxicity: A preliminary study

ObjectiveThe genotype-phenotype relationship in cisplatin-induced ototoxicity remains unclear. By assessing early shifts in distortion product otoacoustic emission (DPOAE) levels after initial cisplatin administration, we aimed to discriminate patients’ susceptibility to cisplatin-induced ototoxicity and elucidate their genetic background. Study DesignA prospective cross-sectional study. SettingTertiary referral hospital in Japan. PatientsTwenty-six patients with head and neck cancer were undergoing chemoradiotherapy with three cycles of 100 mg/m2 cisplatin. InterventionsRepetitive pure-tone audiometry and DPOAE measurements, and blood sampling for DNA extraction were performed. Patients were grouped into early ototoxicity presence or absence based on whether DPOAE level shifts exceeded the corresponding reference limits of the 21-day test interval. Main Outcome MeasuresHearing thresholds after each cisplatin cycle, severity of other adverse events, and polymorphisms in cisplatin-induced ototoxicity-associated genes were compared. ResultsEarly ototoxicity was present in 14 and absent in 12 patients. Ototoxicity presence on DPOAEs was associated with greater progression of hearing loss in frequencies ≥2 kHz throughout therapy and with higher ototoxicity grades compared with ototoxicity absence. Ototoxicity was further associated with grade ≥2 nausea. Ototoxicity presence was genetically associated with the GSTT1 null genotype and G-allele of NFE2L2 rs6721961, whereas ototoxicity absence was associated with the GSTM1 null genotype. Dose-dependent progression of hearing loss was the greatest in the combined genotype pattern of GSTT1 null and the T/G or G/G variants of rs6721961. ConclusionEarly DPOAE changes reflected genetic vulnerability to cisplatin-induced ototoxicity. Hereditary insufficiency of the antioxidant defense system causes severe cisplatin-induced hearing loss and nausea.

4-octyl itaconate alleviates cisplatin-induced ferroptosis possibly via activating the NRF2/HO-1 signalling pathway.

Ferroptosis, characterized by iron-dependent lipid reactive oxygen species (ROS) accumulation, plays a pivotal role in cisplatin-induced ototoxicity. Existing research has suggested that in cisplatin-mediated damage to auditory cells and hearing loss, ferroptosis is partially implicated. 4-Octyl itaconate (4-OI), derived from itaconic acid, effectively permeates cell membranes, showcasing potent anti-inflammatory as well as antioxidant effects in several disease models. Our study aimed to investigate the effect of 4-OI on cisplatin-induced ferroptosis and the underlying molecular mechanisms. The survival rates of HEI-OC1 cells and mice cochlea hair cells were measured by CCK8 and immunofluorescence, respectively. The auditory brainstem response (ABR) audiometry was used to detect changes in hearing thresholds in mice before and after treatment. Levels of ROS were evaluated by DCFH-DA. Real-time PCR quantified inflammatory cytokines TNF-α, IL-6 and IL-1β. Network Pharmacology and RNA sequencing (RNA-seq) analysis of the potential mechanism of 4-OI resistance to cisplatin-induced ferroptosis. The expressions of ferroptosis-related factors (GPX4, SLC7A11 and PTGS2) and important antioxidant factors (NRF2, HO-1, GCLC and NQO1) were tested by real-time PCR, Western blot and immunofluorescence. Results demonstrated cisplatin-induced significant ROS and inflammatory factor release, reduced NRF2 expression, hindered nuclear translocation and activated ferroptosis. Pretreatment with 4-OI exhibited anti-inflammatory and antioxidant effects, along with resistance to ferroptosis, ultimately mitigating cisplatin-induced cell loss. In the present study, we show that 4-OI inhibits cisplatin-induced ferroptosis possibly through activation of the NRF2/HO-1 signalling pathway, thereby exerting a protective effect against cisplatin-induced damage to auditory cells, and providing a new therapeutic strategy for cisplatin-induced hearing loss.

Inhibition of CISD1 attenuates cisplatin-induced hearing loss in mice via the PI3K and MAPK pathways

Cisplatin is an effective chemotherapeutic drug for different cancers, but it also causes severe and permanent hearing loss. Oxidative stress and mitochondrial dysfunction in cochlear hair cells (HCs) have been shown to be important in the pathogenesis of cisplatin-induced hearing loss (CIHL). CDGSH iron sulfur domain 1 (CISD1, also known as mitoNEET) plays a critical role in mitochondrial oxidative capacity and cellular bioenergetics. Targeting CISD1 may improve mitochondrial function in various diseases. However, the role of CISD1 in cisplatin-induced ototoxicity is unclear. Therefore, this study was performed to assess the role of CISD1 in cisplatin-induced ototoxicity. We found that CISD1 expression was significantly increased after cisplatin treatment in both HEI-OC1 cells and cochlear HCs. Moreover, pharmacological inhibition of CISD1 with NL-1 inhibited cell apoptosis and reduced mitochondrial reactive oxygen species accumulation in HEI-OC1 cells and cochlear explants. Inhibition of CISD1 with small interfering RNA in HEI-OC1 cells had similar protective effects. Furthermore, NL-1 protected against CIHL in adult C57 mice, as evaluated by the auditory brainstem response and immunofluorescent staining. Mechanistically, RNA sequencing revealed that NL-1 attenuated CIHL via the PI3K and MAPK pathways. Most importantly, NL-1 did not interfere with the antitumor efficacy of cisplatin. In conclusion, our study revealed that targeting CISD1 with NL-1 reduced reactive oxygen species accumulation, mitochondrial dysfunction, and apoptosis via the PI3K and MAPK pathways in HEI-OC1 cell lines and mouse cochlear explants in vitro, and it protected against CIHL in adult C57 mice. Our study suggests that CISD1 may serve as a novel target for the prevention of CIHL.

Inhibition of Gpx4-mediated ferroptosis alleviates cisplatin-induced hearing loss in C57BL/6 mice

Cisplatin-induced hearing loss is a common side effect of cancer chemotherapy in clinics, however, the mechanism of cisplatin-induced ototoxicity is still not completely clarified. Cisplatin-induced ototoxicity is mainly associated with the production of reactive oxygen species, activation of apoptosis, and accumulation of intracellular lipid peroxidation, which also is involved in ferroptosis induction. In this study, the expression of TfR1, a ferroptosis biomarker, was upregulated in the outer hair cells of cisplatin-treated mice. Moreover, several key ferroptosis regulator genes were altered in cisplatin-damaged cochlear explants based on RNA-Seq, implying the induction of ferroptosis. Ferroptosis-related Gpx4 and Fsp1 knockout mice were established to investigate the specific mechanisms associated with ferroptosis in cochleae. Severe OHC loss and progressive damage of synapses in IHC were observed in Atoh1-Gpx4-/- mice. However, Fsp1-/- mice showed no significant hearing phenotype, demonstrating that Gpx4, but not Fsp1, may play an important role in the functional maintenance of HCs. Moreover, findings showed that FDA-approved luteolin could specifically inhibit ferroptosis and alleviate cisplatin-induced ototoxicity through decreased expression of Transferrin and intracellular concentration of ferrous ions. This study indicated that ferroptosis inhibition through the reduction of intracellular ferrous ions might be a potential strategy to prevent cisplatin-induced hearing loss.

Protection from cisplatin-induced hearing loss with lentiviral vector-mediated ectopic expression of the anti-apoptotic protein BCL-XL

Cisplatin is a highly effective chemotherapeutic agent, but it can cause sensorineural hearing loss (SNHL) in patients. Cisplatin-induced ototoxicity is closely related to the accumulation of reactive oxygen species (ROS) and subsequent death of hair cells (HCs) and spiral ganglion neurons (SGNs). Despite various strategies to combat ototoxicity, only one therapeutic agent has thus far been clinically approved. Therefore, we have developed a gene therapy concept to protect cochlear cells from cisplatin-induced toxicity. Self-inactivating lentiviral (LV) vectors were used to ectopically express various antioxidant enzymes or anti-apoptotic proteins to enhance the cellular ROS scavenging or prevent apoptosis in affected cell types. In direct comparison, anti-apoptotic proteins mediated a stronger reduction in cytotoxicity than antioxidant enzymes. Importantly, overexpression of the most promising candidate, Bcl-xl, achieved an up to 2.5-fold reduction in cisplatin-induced cytotoxicity in HEI-OC1 cells, phoenix auditory neurons, and primary SGN cultures. BCL-XL protected against cisplatin-mediated tissue destruction in cochlear explants. Strikingly, invivo application of the LV BCL-XL vector improved hearing and increased HC survival in cisplatin-treated mice. In conclusion, we have established a preclinical gene therapy approach to protect mice from cisplatin-induced ototoxicity that has the potential to be translated to clinical use in cancer patients.

Inhibition of the HMGB1/RAGE axis protects against cisplatin-induced ototoxicity via suppression of inflammation and oxidative stress.

As an anti-tumor drug widely used in the clinic, cisplatin is limited by its ototoxic side effects associated with various factors, including inflammatory responses. Receptor for Advanced Glycation Endproducts (RAGE) recognizes damage-associated molecular patterns (DAMPs) and promotes stress and inflammation. This study intended to determine the potential behavior of the HMGB1/RAGE axis after cisplatin injury and whether it has a protective effect after inhibiting this pathway. We used FPS-ZM1, a RAGE inhibitor, to modulate the axis of HMGB1/RAGE in neonatal mouse cochlear explants and C57BL/6 mice in vivo. Apoptosis was identified by Annexin V-FITC/PI assay, Cleaved Caspase-3, and TUNEL staining. Reactive oxygen species (ROS) level was assessed by MitoSOX Red and CellROX Green assay. The expression of proteins associated with the HMGB1/RAGE axis and apoptosis was observed by western blotting. The expression of inflammatory cytokines was evaluated by qPCR. The protective effect of HMGB1/RAGE knockdown was also assessed on cisplatin-induced ototoxicity. These results demonstrated that cisplatin could activate the HMGB1/RAGE pathway in cochlear hair cells and release inflammatory factors. Pretreatment with FPS-ZM1 alleviated cisplatin-induced ototoxicity in vivo and in vitro. Knocking down HMGB1 and RAGE achieved specific protective effects. Altogether, inhibiting HMGB1/RAGE axis can reverse the increase of ROS accumulation, the activation of apoptosis, and the production of inflammatory reactions after cisplatin injury. FPS-ZM1 could resist the ototoxicity of cisplatin by suppressing the HMGB1/RAGE signal pathway, and it may be considered the new otoprotective potential strategy for hearing loss.

20(S)-Ginsenoside Rh1 alleviates sevoflurane-induced ototoxicity by reducing oxidative stress levels.

Sevoflurane is an inhalational anesthetic widely used in pediatric surgery. However, animal studies have shown that multiple sevoflurane exposures during the neonatal period led to ototoxicity. 20(S)-Ginsenoside Rh1, a ginsenoside extract, protects against cisplatin-induced ototoxicity by scavenging free radicals. This study aimed to assess the effects of Rh1 on sevoflurane-induced ototoxicity. Neonatal cochlear explants and House Ear Institute-Organ of Corti 1 (HEI-OC1) cells were cultured and randomly divided into three groups: the control group, the sevoflurane group and the Rh1 pretreatment group. We pretreated cochlear explants or HEI-OC1 cells with 100 μM Rh1 2 hours before performing sevoflurane exposure. Immunofluorescence was used to detect hair cells and spiral ganglion neurons. Cell Counting Kit-8 assay was used to determine cell viability. Annexin V-fluorescein isothiocyanate and propidium iodide were used to evaluate apoptosis. CellROX-Green and MitoSOX-Red probes were used to measure the amount of reactive oxygen species (ROS). Tetramethylrhodamine methyl ester labeling was used to examine mitochondrial membrane potential. Rh1 attenuated spiral ganglion neuron nerve fibers and synapses degeneration in cochlear explants after sevoflurane exposure. Rh1 significantly increased the viability of HEI-OC1 cells, reduced reactive oxygen species accumulation in HEI-OC1 cells, and prevented mitochondrial damage in HEI-OC1 cells after sevoflurane exposure. These findings suggest that Rh1 is a promising drug for preventing sevoflurane-induced ototoxicity.

Formononetin ameliorates cisplatin-induced hair cell death via activation of the PI3K/AKT-Nrf2 signaling pathway

Cisplatin (CDDP) stands as a highly effective chemotherapeutic agent; however, its ototoxicity remains a perplexing challenge in the field. Formononetin (FMNT), a potent flavonoid isolated from Astragalus membranaceus, displays a diverse range of promising pharmacological activities, encompassing antioxidant, anti-apoptotic, and anti-inflammatory effects. Nonetheless, the advantageous effects of FMNT on cisplatin-induced cochlear hair cell injury demand further investigation. This study aimed to assess the protective properties of FMNT against cisplatin-induced hair cell damage by conducting in vitro assays on explant-cultured cochlear hair cells. The findings revealed that FMNT exhibited a notable reduction in cisplatin-induced hair cell apoptosis. Also, FMNT effectively mitigated the accumulation of reactive oxygen species and mitochondrial damage in cochlear explants exposed to cisplatin, while also restoring the turnover of the reduced glutathione (GSH)/glutathione disulfide (GSSG) ratio. Furthermore, our study demonstrated that FMNT protects hair cells against CDDP injury through the activation of the PI3K/AKT-Nrf2 signaling pathway. Consequently, formononetin emerges as a potential therapeutic agent for the treatment of cisplatin-induced ototoxicity.

AdipoRon reduces cisplatin-induced ototoxicity in hair cells:possible relation to the regulation of mitochondrial biogenesis

AdipoRon (AR) can exert antidiabetic and anti-inflammatory effects by maintaining mitochondrial structure and function. The present study was designed to explore whether AR protects the auditory cells from cisplatin-induced damage and, if so, to probe the possible mechanisms underlying its action on this type of cells. Cell viability and apoptosis in House Ear Institute-Organization of Corti 1 (HEI-OC1 cells) and mouse cochlea hair cells (HCs) were detected by CCK8 and immunofluorescence. The expressions of apoptosis-related proteins (cleaved caspase-3 and Bcl-2), adiponectin receptor 1 (AdipoR 1) and the key factors relevant to mitochondrial biogenesis（SIRT1 and TFAM）were determined by Western blot and immunofluorescence. Changes in apoptotic rate and expression of SIRT1 and TFAM after silencing of AdipoR 1 (AdipoR 1-siRNA) in HEI-OC1 cells were measured by flow cytometry and Western blot. The levels of reactive oxygen species (ROS) were evaluated by MitoSox red staining. We found that 30 μM cisplatin exposure induced severe cellular damage, which resulted from activation of the mitochondrial apoptotic pathway. Cisplatin decreased the expression of AdipoR 1, SIRT1, and TFAM proteins, leading to impaired mitochondrial biogenesis and increased mitochondrial ROS production. 10 μM AR pre-treatment enhanced mitochondrial biogenesis, decreased mitochondrial ROS levels, alleviated imbalances in the mitochondrial apoptotic pathway, thus reducing cisplatin-induced apoptosis. Taken together, this work reveals that AR exerts anti-apoptotic effects, possibly via regulating mitochondrial biogenesis and function. Interestingly, AR might possess the promising potential to be a novel drug for the prevention and/ or treatment of cisplatin-induced ototoxicity.

Puerarin inhibits cisplatin-induced ototoxicity in mice through regulation of TRPV1-dependent calcium overload

Puerarin (PUE), a flavonoid derivative with vasodilatory effects found in the traditional Chinese medicine kudzu, has anti-sensorineural hearing loss properties. However, the mechanism of its protective effect against ototoxicity is not well understood. In this study, we used in vitro and in vivo methods to investigate the protective mechanism of puerarin against cisplatin (CDDP)-induced ototoxicity. We established an ototoxicity model of CDDP in BALB/c mice and assessed the degree of hearing loss and cochlear cell damage. We used bioinformatics analysis, molecular docking, histological analysis, and biochemical and molecular biology to detect the expression of relevant factors. Our results show that puerarin improved CDDP-induced hearing loss and reduced hair cell loss. It also blocked CDDP-induced activation of TRPV1 and inhibited activation of IP3R1 to prevent intracellular calcium overload. Additionally, puerarin blocked CDDP-stimulated p65 activation, reduced excessive ROS production, and alleviated cochlear cell apoptosis. Our study provides new evidence and potential targets for the protective effect of puerarin against drug-induced hearing loss. Puerarin ameliorates cisplatin-induced ototoxicity and blocks cellular apoptosis by inhibiting CDDP activated TRPV1/IP3R1/p65 pathway, blocking induction of calcium overload and excessive ROS expression.

CORM‑2 reduces cisplatin accumulation in the mouse inner ear and protects against cisplatin-induced ototoxicity

IntroductionCisplatin is a life-saving anticancer compound used to treat multiple solid malignant tumors, while it causes permanent hearing loss. There is no known cure, and the FDA has not approved any preventative treatment for cisplatin-based ototoxicity. ObjectivesThis study investigated whether the carbon monoxide (CO)-releasing tricarbonyldichlororuthenium (II) dimer, CORM-2, reverses cisplatin-induced hearing impairment and reduces cisplatin accumulation in the mouse inner ear. MethodsMale 6-week-old BALB/c mice were randomly assigned to one of the following groups: control (saline-treated, i.p.), CORM-2 only (30 mg/kg, i.p., four doses), cisplatin only (20 mg/kg, i.p., one dose), and CORM-2 + cisplatin, to determine whether cisplatin-based hearing impairment was alleviated by CORM-2 treatment. ResultsOur results revealed CORM-2 significantly attenuated cisplatin-induced hearing loss in young adult mice. CORM-2 co-treatment significantly decreased platinum accumulation in the inner ear and activated the plasma membrane repair system of the stria vascularis. Moreover, CORM-2 co-treatment significantly decreased cisplatin-induced inflammation, apoptosis, and cochlear necroptosis. Because the stria vascularis is the likely cochlear entry point of cisplatin, we next focused on the microvasculature. Cisplatin induced increased extravasation of a chromatic tracer (fluorescein isothiocyanate [FITC]-dextran, MW 75 kDa) around the cochlear microvessels at 4 days post-treatment; this extravasation was completely inhibited by CORM-2 co-therapy. CORM-2 co-treatment effectively maintained the integrity of stria vascularis components including endothelial cells, pericytes, and perivascular-resident macrophage-type melanocytes. ConclusionCORM-2 co-therapy substantially protects against cisplatin-induced ototoxicity by reducing platinum accumulation and toxic cellular stress responses. These data indicate that CORM-2 co-treatment may be translated into clinical strategy to reduce cisplatin-induced hearing loss.

Molecular Characteristics of Cisplatin-Induced Ototoxicity and Therapeutic Interventions.

Cisplatin is a commonly used chemotherapeutic agent with proven efficacy in treating various malignancies, including testicular, ovarian, cervical, breast, bladder, head and neck, and lung cancer. Cisplatin is also used to treat tumors in children, such as neuroblastoma, osteosarcoma, and hepatoblastoma. However, its clinical use is limited by severe side effects, including ototoxicity, nephrotoxicity, neurotoxicity, hepatotoxicity, gastrointestinal toxicity, and retinal toxicity. Cisplatin-induced ototoxicity manifests as irreversible, bilateral, high-frequency sensorineural hearing loss in 40-60% of adults and in up to 60% of children. Hearing loss can lead to social isolation, depression, and cognitive decline in adults, and speech and language developmental delays in children. Cisplatin causes hair cell death by forming DNA adducts, mitochondrial dysfunction, oxidative stress, and inflammation, culminating in programmed cell death by apoptosis, necroptosis, pyroptosis, or ferroptosis. Contemporary medical interventions for cisplatin ototoxicity are limited to prosthetic devices, such as hearing aids, but these have significant limitations because the cochlea remains damaged. Recently, the U.S. Food and Drug Administration (FDA) approved the first therapy, sodium thiosulfate, to prevent cisplatin-induced hearing loss in pediatric patients with localized, non-metastatic solid tumors. Other pharmacological treatments for cisplatin ototoxicity are in various stages of preclinical and clinical development. This narrative review aims to highlight the molecular mechanisms involved in cisplatin-induced ototoxicity, focusing on cochlear inflammation, and shed light on potential antioxidant and anti-inflammatory therapeutic interventions to prevent or mitigate the ototoxic effects of cisplatin. We conducted a comprehensive literature search (Google Scholar, PubMed) focusing on publications in the last five years.

Lysophosphatidic acid exerts protective effects on HEI-OC1 cells against cytotoxicity of cisplatin by decreasing apoptosis, excessive autophagy, and accumulation of ROS

Lysophosphatidic acid (LPA) is an active phospholipid signaling molecule that binds to six specific G protein-coupled receptors (LPA1-6) on the cell surface and exerts a variety of biological functions, including cell migration and proliferation, morphological changes, and anti-apoptosis. The earliest study from our group demonstrated that LPA treatment could restore cochlear F-actin depolymerization induced by noise exposure, reduce hair cell death, and thus protect hearing. However, whether LPA could protect against cisplatin-induced ototoxicity and which receptors play the major role remain unclear. To this end, we integrated the HEI-OC1 mouse cochlear hair cell line and zebrafish model, and found that cisplatin exposure induced a large amount of reactive oxygen species accumulation in HEI-OC1 cells, accompanied by mitochondrial damage, leading to apoptosis and autophagy. LPA treatment significantly attenuated autophagy and apoptosis in HEI-OC1 cells after cisplatin exposure. Further investigation revealed that all LPA receptors except LPA3 were expressed in HEI-OC1 cells, and the mRNA expression level of LPA1 receptor was significantly higher than that of other receptors. When LPA1 receptor was silenced, the protective effect of LPA was reduced and the proportion of apoptosis cells was increased, indicating that LPA-LPA1 plays an important role in protecting HEI-OC1 cells from cisplatin-induced apoptosis. In addition, the behavioral trajectory and in vivo fluorescence imaging results showed that cisplatin exposure caused zebrafish to move more actively, and the movement speed and distance were higher than those of the control and LPA groups, while LPA treatment reduced the movement behavior. Cisplatin caused hair cell death and loss in zebrafish lateral line, and LPA treatment significantly protected against hair cell death and loss. LPA has a protective effect on hair cells in vitro and in vivo against the cytotoxicity of cisplatin, and its mechanism may be related to reducing apoptosis, excessive autophagy and ROS accumulation.

Circulating IL-17 reduces the risk of cisplatin-induced hearing loss in children: a bidirectional two-sample Mendelian randomization study

Studies have reported that cytokines and their related signaling pathways play a role in inner ear diseases. In clinical practice, approximately 50% of pediatric cancer patients experience irreversible hearing loss after cisplatin treatment. However, currently, there is a lack of systematic research on the causal relationship between circulating cytokines and cisplatin-induced hearing loss in children. Genetic variant data for 41 circulating cytokines were obtained from a meta-analysis of genome-wide association studies (GWAS) among 8293 individuals of Finnish descent. The GWAS data for Cisplatin-induced hearing loss in children were derived from a multicenter cohort of European pediatric cancer patients and survivors (N = 390), including both cases with hearing loss after cisplatin chemotherapy and controls without hearing loss. Multiple methods were employed for bidirectional Mendelian randomization (MR) estimation. Bonferroni correction was applied to adjust the original P-values, followed by a series of sensitivity analyses. In the directional Mendelian randomization (MR) analysis, it was found that IL-17 was significantly associated with a reduced risk of Cisplatin-induced hearing loss in children (OR: 0.18, CI: 0.06–0.48, P < 0.001, FDR = 0.041). In the reverse MR analysis, there were some nominal causal relationships of Cisplatin-induced hearing loss in children with certain cytokines [M-CSF: (OR: 1.04, CI: 1.01–1.08, P = 0.010, FDR = 0.41); IL-2RA: (OR: 1.03, CI: 1.00–1.05, P = 0.044, FDR = 0.447); MIP-1β: (OR: 1.02, CI: 1.00–1.04, P = 0.041, FDR = 0.447)]. leave-one-out analysis demonstrated that only M-CSF exhibited stability. These findings reveal a causal relationship between IL-17 and cisplatin-induced hearing loss in children. Further research is needed to determine the potential protective mechanisms of IL-17 in cisplatin-induced ototoxicity.

Practice of Monitoring Cisplatin-Induced Ototoxicity by Audiology, ENT, and Oncology Specialists: A Survey-Based Study in a Single Italian Medical Center.

Ototoxic drugs can result in hearing loss and tinnitus. Early detection of the ototoxic process can help minimize or prevent these consequences. The American Speech-Language-Hearing Association has provided guidelines for monitoring ototoxicity, whereas Italy has not yet implemented a national monitoring protocol. This study aims to assess the current state of ototoxicity monitoring in patients receiving cisplatin therapy. A self-administered survey has been used to gather information from oncologists, audiologists, and ENT specialists. The research was conducted at Santa Maria della Misericordia hospital in Perugia. Two questionnaires were administered, one to ENT/audiology specialists and another to oncology specialists. Both questionnaires were used to collect information on awareness of chemotherapy-induced ototoxicity. A comprehensive understanding of cisplatin-induced ototoxicity has been widely established (100%). The most commonly reported audiological symptoms by patients were hearing loss (100%) and tinnitus (87.5%). The majority of ENT and audiologists (93.8%) and oncologists (92.9%) expressed the need for a specific ototoxic monitoring program. However, they noted the absence of a well-defined ototoxicity monitoring protocol. A well-established and efficient ototoxic monitoring system facilitates early detection of ototoxic hearing loss and subsequent rehabilitation of inevitable hearing impairment.