Chloroquine and hydroxychloroquine ototoxicity; potential implications for SARS-CoV-2 treatment. A brief review of the literature.

INTRODUCTION: Current clinical evidences do not support any specific treatment against SARS-CoV-2. Chloroquine (CQ) and hydroxychloroquine (HCQ) are typically used in the treatment of rheumatoid arthritis, systemic lupus erythematosus and malaria; they have been considered for off-label and compassionate use in several countries against moderate to severe cases of COVID-19 and there's actually a massive demand of these two drugs. The aim of this paper is to briefly review the published literature, summarizing evidences about audiological implications after CQ and HCQ treatment. METHODS: We conducted a review of the literature on Medline and Pubmed platforms from 27th May 2020 to 30 May 2020. We combined MeSH terms of "chloroquine", "hydroxychloroquine", "ototoxicity", "hearing loss", "tinnitus", "deafness" and "hearing". Publications with relevant data were included. Selected data (authors, country and year; sample size; study design; audiological side effects) were extracted and summarized in a table. RESULTS: Of 45 initial studies, 14 met inclusion criteria. The authors found xix cases of HCQ ototoxicity; Tinnitus was reported in 2 cases, and it was found to be reversible or irreversible. Sensorineural hearing loss after HCQ use was reported in 7 patients; it was found to be irreversible or partially reversible after discontinuation of HCQ in 6 cases. Eight papers reporting CQ ototoxicity were; tinnitus was not reported by any authors. Sensorineural hearing loss after taking CQ was reported in 6 patients; it was found to be irreversible after discontinuation of CQ in 5 patients. One patient showed abnormal gait after a single intramuscular injection of CQ. Thirteen patients' Auditory Brainstem Response (ABR) were found to be abnormal, but they resolved after CQ discontinuation. CONCLUSIONS: CQ and HCQ related ototoxicity is widely reported in the literature although the pathophysiological mechanism is not well known. Current data are not sufficient enough to support the use of CQ and HCQ as therapy for COVID-19, but considering the growing demand for these two drugs and the number of people around the world who have taken and will take CQ and HCQ, it must necessarily consider the clinical and social impact of long term audiological side effects.

Exosomes derived from mouse inner ear stem cells attenuate gentamicin-induced ototoxicity in vitro through the miR-182-5p/FOXO3 axis.

Gentamicin-induced cochlear hair cell ototoxicity, such as oxidative stress and apoptosis, could be attenuated by mouse inner ear stem cells (IESCs). However, it is still unclear whether such protective effects could be mediated by exosomes derived from IESCs (IESCs-ex). In the present study, HEI-OC1 cells were exposed to gentamicin (2 mM) to establish an ototoxicity model and further treated with exosomes isolated from miR-182-5p transferred or non-transferred IESCs. IESCs-ex improved HEI-OC1 cell viability, as assayed by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide method, and alleviated the oxidative stress response induced by the gentamicin treatment, as confirmed by measuring the malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase levels. IESCs-ex increased relative miR-182-5p expression and decreased FOXO3 expression in the gentamicin-exposed HEI-OC1 cells. Furthermore, exosomes derived from miR-182-5p mimics that were pre-treated with IESCs could increase miR-182-5p and Bcl-2 expressions and decrease FOXO3 and Bax expressions in gentamicin-exposed HEI-OC1 cells. All of these results indicate that IESCs-ex could attenuate gentamicin-induced HEI-OC1 cell apoptosis and oxidative stress through the miR-182-5p/FOXO3 axis.

Perspectives and practices of ototoxicity monitoring.

BACKGROUND: Treatment of cancer with cisplatin can result in hearing loss. Given the increasing burden of cancer in Africa, appropriate and timely identification, intervention and management of hearing loss in affected patients is of paramount importance. OBJECTIVES: This study describes the perspectives and practices of healthcare professionals in relation to cisplatin-associated ototoxicity at an institution treating patients diagnosed with cancer. METHOD: A concurrent triangulation study design was used to collect quantitative data from seven oncologists, nine nurses and 13 pharmacists using self-administered questionnaires, and qualitative data from four audiologists through semi-structured interviews for this hospital-based study, conducted in South Africa. RESULTS: Levels of awareness of cisplatin-associated ototoxicity varied with only 33% of the nursing personnel being aware in comparison to the oncologists and pharmacists. Oncologists were identified as the main custodians for providing information to patients. Whilst 82% of the participants considered the audiologist to be part of the oncology team, there was no provision for ototoxicity monitoring in the chemotherapy protocols, nor any ototoxicity-monitoring programme in place. There was no evidence that knowledge of cisplatin-associated ototoxicity translated into an appropriate management strategy for such patients. CONCLUSION: Healthcare personnel overseeing the care and management of cancer patients need to improve their awareness of ototoxicity and refer timeously for audiological evaluation. Audiologists require greater awareness of monitoring programmes to appropriately implement and manage such programmes within a cancer platform and be part of a multidisciplinary team.

Clinical and Genome-wide Analysis of Cisplatin-induced Tinnitus Implicates Novel Ototoxic Mechanisms.

PURPOSE: Cisplatin, a commonly used chemotherapeutic, results in tinnitus, the phantom perception of sound. Our purpose was to identify the clinical and genetic determinants of tinnitus among testicular cancer survivors (TCS) following cisplatin-based chemotherapy. EXPERIMENTAL DESIGN: TCS (n = 762) were dichotomized to cases (moderate/severe tinnitus; n = 154) and controls (none; n = 608). Logistic regression was used to evaluate associations with comorbidities and SNP dosages in genome-wide association study (GWAS) following quality control and imputation (covariates: age, noise exposure, cisplatin dose, genetic principal components). Pathway over-representation tests and functional studies in mouse auditory cells were performed. RESULTS: Cisplatin-induced tinnitus (CisIT) significantly associated with age at diagnosis (P = 0.007) and cumulative cisplatin dose (P = 0.007). CisIT prevalence was not significantly greater in 400 mg/m2-treated TCS compared with 300 (P = 0.41), but doses >400 mg/m2 (median 580, range 402-828) increased risk by 2.61-fold (P < 0.0001). CisIT cases had worse hearing at each frequency (0.25-12 kHz, P < 0.0001), and reported more vertigo (OR = 6.47; P < 0.0001) and problems hearing in a crowd (OR = 8.22; P < 0.0001) than controls. Cases reported poorer health (P < 0.0001) and greater psychotropic medication use (OR = 2.4; P = 0.003). GWAS suggested a variant near OTOS (rs7606353, P = 2 × 10-6) and OTOS eQTLs were significantly enriched independently of that SNP (P = 0.018). OTOS overexpression in HEI-OC1, a mouse auditory cell line, resulted in resistance to cisplatin-induced cytotoxicity. Pathway analysis implicated potassium ion transport (q = 0.007). CONCLUSIONS: CisIT associated with several neuro-otological symptoms, increased use of psychotropic medication, and poorer health. OTOS, expressed in the cochlear lateral wall, was implicated as protective. Future studies should investigate otoprotective targets in supporting cochlear cells.

Recommendations for ototoxicity surveillance for childhood, adolescent, and young adult cancer survivors: a report from the International Late Effects of Childhood Cancer Guideline Harmonization Group in collaboration with the PanCare Consortium.

Childhood, adolescent, and young adult (CAYA) cancer survivors treated with platinum-based drugs, head or brain radiotherapy, or both have an increased risk of ototoxicity (hearing loss, tinnitus, or both). To ensure optimal care and reduce consequent problems-such as speech and language, social-emotional development, and learning difficulties-for these CAYA cancer survivors, clinical practice guidelines for monitoring ototoxicity are essential. The implementation of surveillance across clinical settings is hindered by differences in definitions of hearing loss, recommendations for surveillance modalities, and remediation. To address these deficiencies, the International Guideline Harmonization Group organised an international multidisciplinary panel, including 32 experts from ten countries, to evaluate the quality of evidence for ototoxicity following platinum-based chemotherapy and head or brain radiotherapy, and formulate and harmonise ototoxicity surveillance recommendations for CAYA cancer survivors.