Paraoxonase Activity and Oxidative Status in Patients with Tinnitus

The effect of MemoVigor 2 on recent-onset idiopathic tinnitus: a randomized double-blind placebo-controlled clinical trial

Background: Tinnitus is a common symptom associated with the conscious perception of sound in the absence of a corresponding external or internal sound source, which can severely impact quality of life. Because of the current limited understanding of the precise pathophysiological mechanism of idiopathic tinnitus, no curable treatment has been attained yet. A food supplement trading as MemoVigor 2, which contains a combination of therapeutic ingredients with mainly antioxidant activity, has been used in the treatment of tinnitus. The objective of our study was to evaluate the effectiveness of MemoVigor 2 in the treatment of recent-onset idiopathic tinnitus. Methods: In a prospective single-centre randomized, double-blind, placebo-controlled clinical trial we studied 204 patients with idiopathic tinnitus divided into two groups: 104 patients who received MemoVigor 2 and 100 patients treated with placebo. To evaluate changes in tinnitus we used (1) audiometry/tympanometry; (2) specific measures of tinnitus perception, including tinnitus pitch, loudness at tinnitus pitch, loudness at 1 kHz, minimum masking level, and residual inhibition; (3) questionnaires of tinnitus handicap inventory, mini tinnitus questionnaire and patients' global impression of change. All patients underwent this test battery at the beginning of the study and in a repeat post-3-month session. Results: All tinnitus measures, including pitch, loudness, minimum masking level and residual inhibition improved significantly in the intervention group. Most of these measures improved in the placebo group too, but in a lesser degree. All questionnaire scores diminished significantly in both groups, but the degree of decrease was greater in the intervention group. The participants' tinnitus outcome reported after treatment using the patients' global impression of change score differed significantly between the two groups, with greater improvement observed in the intervention group. Conclusion: We found that the use of MemoVigor 2 improved recent-onset tinnitus, as proved by a set of tests performed for its evaluation, including audiometric measures, specific measures of tinnitus perception and tinnitus questionnaires. Tinnitus in the placebo group improved too, but to a lesser degree. Clinical Trial Registration: isrctn.com, Identifier ISRCTN16025480.

The Relevance of Autophagy within Inner Ear in Baseline Conditions and Tinnitus-Related Syndromes

Tinnitus is the perception of noise in the absence of acoustic stimulation (phantom noise). In most patients suffering from chronic peripheral tinnitus, an alteration of outer hair cells (OHC) starting from the stereocilia (SC) occurs. This is common following ototoxic drugs, sound-induced ototoxicity, and acoustic degeneration. In all these conditions, altered coupling between the tectorial membrane (TM) and OHC SC is described. The present review analyzes the complex interactions involving OHC and TM. These need to be clarified to understand which mechanisms may underlie the onset of tinnitus and why the neuropathology of chronic degenerative tinnitus is similar, independent of early triggers. In fact, the fine neuropathology of tinnitus features altered mechanisms of mechanic-electrical transduction (MET) at the level of OHC SC. The appropriate coupling between OHC SC and TM strongly depends on autophagy. The involvement of autophagy may encompass degenerative and genetic tinnitus, as well as ototoxic drugs and acoustic trauma. Defective autophagy explains mitochondrial alterations and altered protein handling within OHC and TM. This is relevant for developing novel treatments that stimulate autophagy without carrying the burden of severe side effects. Specific phytochemicals, such as curcumin and berberin, acting as autophagy activators, may mitigate the neuropathology of tinnitus.

Limited Link of Common Blood Parameters with Tinnitus

Background: Tinnitus severity is generally assessed by psychometric and audiological instruments. However, no objective measure exists to evaluate the subjective discomfort and suffering caused by this hearing phenomenon. The objective of this work was to determine the possible blood parameters for diagnostics and therapy. Methods: We measured tinnitus distress by using the Tinnitus Questionnaire (TQ) and collected tinnitus-related audiological measures, namely the hearing threshold (HT), tinnitus loudness (TL), and sensation level (SL, i.e., the tinnitus loudness/hearing threshold at a tinnitus frequency). Blood samples were taken from 200 outpatients of the Tinnitus Centre of the Charité, and 46 routine blood count parameters were examined. The possible interactions were determined by (robust) linear models. Results: Tinnitus distress and audiological measurements were largely uncorrelated but could partly be predicted by selected blood parameters. First, the erythrocyte counts predicted tinnitus distress to a small extent. Second, the levels of vitamin D3 explained about 6% of tinnitus loudness and, age-dependently, the hearing threshold variability. Last, the levels of uric acid explained about 5% of the sensation level variability. Conclusions: Tinnitus is a multidimensional phenomenon. The marginal influences of blood markers suggest the possible roles of inflammation and oxidative stress produced by psychological or somatic burdens. Clinically, a vitamin D substitution (in older patients) might have a hearing-protective effect.

Supplementation with açaí (Euterpe Oleracea Martius) for the treatment of chronic tinnitus: effects on perception, anxiety levels and oxidative metabolism biomarkers

PURPOSE

To investigate the effects of antioxidant supplementation with açaí extract on the discomfort with chronic tinnitus and the relationship with the levels of anxiety and oxidative metabolism, not excluding the overlap of diseases.

METHODS

Randomized, placebo-controlled clinical trial. 30 individuals participated, with an average of 50.5 years, 14 males and 16 females, with normal hearing thresholds or sensorineural hearing loss up to mild degree, divided into two groups: Placebo Group (without active) and, Açaí Group (100mg of açaí extract). The following procedures were applied before and after three months of treatments: Tinnitus Handicap Inventory (THI), Beck's Anxiety Inventory (BAI) and blood samples for evaluation of oxidative stress biomarkers (Lipid Peroxidation and Protein Carbonylation).

RESULTS

There was a reduction in the discomfort of tinnitus for the açaí group verified through THI (p = 0.006). Significant differences were found in the score of common symptoms for anxiety disorders in the placebo group (p = 0.016), however, the same was not observed for oxidative metabolism biomarkers, although there was a decrease in post-treatment values for all groups.

CONCLUSION

Oral antioxidant supplementation, with açaí extract, showed favorable effects on tinnitus, reducing discomfort with the symptom, regardless of the underlying etiology, and can be considered a treatment modality. However, the effect of this supplementation on anxiety symptoms and oxidative stress biomarkers needs further investigation.

The Role of Manganese, Cadmium, Chromium and Selenium on Subjective Tinnitus

Elevated levels of heavy metals like cadmium (Cd) and manganese (Mn) are known to lead to oxidative damage-related oto-toxicity and decreased levels of chromium (Cr) and selenium (Se) are known to lead to oto-toxicity due to reduced anti-oxidant activity. The aim of the present study was to evaluate serum levels of Cd, Mn, Cr, and Se and their relationship with tinnitus. A total of 48 patients with tinnitus (Group 1) and 40 healthy controls (Group 2) were included in the study. All participants were applied audiology tests. Severity of tinnitus was measured with Tinnitus Severity Index Questionnaire (TSIQ) in group 1. Serum Mn, Cd, Cr, and Se measurements were done by using The Agilent ICP-MS system consisted of a 7700 coupled plasma mass spectrometry (ICP-MS). Serum Cd, Mn, and Cr levels were higher in group 1 and Se level was lower in group 1 than that of group 2. We may conclude that Cd, Mn, Cr, and Se levels could play an important role in etio-pathogenesis of tinnitus, and thereby supplementation or reduction of these elements could be considered as novel therapeutic goals.

Objective and Measurable Biomarkers in Chronic Subjective Tinnitus

Tinnitus is associated with increased social costs and reduced quality of life through sleep disorders or psychological distress. The pathophysiology of chronic subjective tinnitus, which accounts for most tinnitus, has not been clearly elucidated. This is because chronic subjective tinnitus is difficult to evaluate objectively, and there are no objective markers that represent the diagnosis or therapeutic effect of tinnitus. Based on the results of studies on patients with chronic subjective tinnitus, objective and measurable biomarkers that help to identify the pathophysiology of tinnitus have been summarized. A total of 271 studies in PubMed, 303 in EMBASE, and 45 in Cochrane Library were found on biomarkers related to chronic subjective tinnitus published until April 2021. Duplicate articles, articles not written in English, review articles, case reports, and articles that did not match our topic were excluded. A total of 49 studies were included. Three specimens, including blood, saliva, and urine, and a total of 58 biomarkers were used as indicators for diagnosis, evaluation, prognosis, and therapeutic effectiveness of tinnitus. Biomarkers were classified into eight categories comprising metabolic, hemostatic, inflammatory, endocrine, immunological, neurologic, and oxidative parameters. Biomarkers can help in the diagnosis, measure the severity, predict prognosis, and treatment outcome of tinnitus.

Auditory Neural Plasticity in Tinnitus Mechanisms and Management

Tinnitus, which is the perception of sound in the absence of a corresponding external acoustic stimulus, including change of hearing and neural plasticity, has become an increasingly important ailment affecting the daily life of a considerable proportion of the population and causing significant burdens for both the affected individuals and society as a whole. Here, we briefly review the epidemiology and classification of tinnitus, and the currently available treatments are discussed in terms of the available evidence for their mechanisms and efficacy. The conclusion drawn from the available evidence is that there is no specific medication for tinnitus treatment at present, and tinnitus management might provide better solutions. Therapeutic interventions for tinnitus should be based on a comprehensive understanding of the etiology and features of individual cases of tinnitus, and more high quality and large-scale research studies are urgently needed to develop more efficacious medications.

Increased risk of tinnitus in patients with early-onset cataracts: a nationwide population-based case-control study

Background

This study aimed to investigate the association between early-onset cataract and tinnitus using a population-based database.

Methods

Retrospective claims data from the Taiwan National Health Insurance Research Database were analysed. Study subjects comprised patients with early-onset cataract, aged 20–55 years and diagnosed between 2000 and 2010 (n = 2084) and a comparison cohort without the disease (n = 8336). Both cohorts were followed until 2010 to estimate the incidence of tinnitus. To calculate the risk of tinnitus in the case and control groups, Cox proportional hazards models were used and presented as hazard ratios (HRs), adjusted HRs (aHRs) and 95% confidence intervals (CIs).

Results

Patients with early-onset cataract had 1.53-fold increased risk (HR = 1.53, 95% CI = 1.17–2.01, p < 0.01) of developing tinnitus than controls. The number of patients with vertigo (p < 0.0001), insomnia (p < 0.0001), anxiety (p < 0.0001) and hearing loss (p < 0.0001) as comorbidities was also significantly higher in the case group. After adjusting for age, sex and all listed comorbidities, patients with increasing age (aHR = 1.04, 95% CI = 1.02–1.07), early-onset cataract (aHR = 1.32, 95% CI = 1.01–1.74), vertigo (aHR = 1.75, 95% CI = 1.15–2.67), insomnia (aHR = 1.48, 95% CI = 1.14–1.93) and hearing loss (aHR = 6.20, 95% CI = 3.58–10.70) had significantly higher risk of tinnitus.

Conclusions

Patients with early-onset cataract are at an increased risk of developing tinnitus in subsequent years and should receive further evaluation for early diagnosis and management if any signs of tinnitus occur.

The Effect of Antioxidant Supplementation in Patients with Tinnitus and Normal Hearing or Hearing Loss: A Randomized, Double-Blind, Placebo Controlled Trial

Tinnitus is the perception of sound in the absence of any external stimulus. Oxidative stress is possibly involved in its pathogenesis and a variety of antioxidant compounds have been studied as potential treatment approaches. The objective of the present study was to assess the effects of antioxidant supplementation in tinnitus patients. This is a randomized, double-blind, placebo-controlled clinical trial. Patients (N = 70) were randomly allocated to antioxidant supplementation (N = 35) or to placebo (N = 35) for a total of 3 months. Demographic, anthropometric, clinical, and nutritional data were collected. Serum total antioxidant capacity (TAC), oxidized LDL (oxLDL), and superoxide dismutase (SOD), tinnitus loudness, frequency, and minimum masking level (MML), and scores in Tinnitus Handicap Inventory questionnaire (THI), Tinnitus Functional Index (TFI), and Visual Analogue Scale (VAS) were evaluated at baseline and follow-up. Tinnitus loudness and MML significantly decreased from baseline to post measure (p < 0.001) only in the antioxidant group, the overall change being significantly different between the two groups post-intervention (p < 0.001). THI and VAS decreased only in the antioxidant group. Differences in changes in serum TAC, SOD, and oxLDL post-intervention were insignificant. In conclusion, antioxidant therapy seems to reduce the subjective discomfort and tinnitus intensity in tinnitus patients.

Oxidative stress in prelingual sensorineural hearing loss and the effects of cochlear implant application on serum oxidative stress levels

OBJECTIVES

The aim of this study is to investigate oxidative stress conditions in patients with prelingual profound sensorineural hearing loss (SNHL) and the effects of cochlear implant application on oxidative stress. In addition, we also aimed to evaluate the correlation between pre- and post-surgery oxidative stress markers and Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS), Meaningful Use of Speech Scale (MUSS) and Free-Field Audiometry (FFA).

METHODS

This is a prospective controlled study of the Ear-Nose-Throat Department of the Harran University Faculty of Medicine between April 2017 and January 2018. The study included 25 patients with prelingual profound SNHL diagnosis and cochlear implant surgery and 25 healthy control groups. Total thiol, native thiol, disulphide levels and LOOH levels were studied in serum samples taken from the patient group 2 weeks before and 6 months after the cochlear implant surgery and the healthy control group. In addition, IT-MAIS, MUSS and FFA tests, which were used to evaluate the personal development of patients with cochlear implants, were performed at preoperative and postoperative 6th month.

RESULTS

In our study, we found that the levels of native thiol (p < 0.01) and total thiol (p < 0.01) were significantly lower and LOOH (p < 0.04) values were significantly higher in preoperative SNHL patients than control group. We found that native thiol, total thiol values increased and LOOH values decreased in the postoperative with respect to preoperative values. However, the difference between preoperative and post operative values was not statistically significant. The correlation between pre- and post-surgery biochemical data and IT-MAIS, MUSS and FFA tests were found not to be significant.

CONCLUSIONS

Our study suggests that patients with prelingual profound SNHL are under oxidative stress and post-CI surgery data show that there is no significant relief in patients. This study can shed light on the biologic mechanisms between prelingual profound SNHL and oxidative stress.

Evaluation of serum prolidase enzyme activity and oxidative stress in patients with tinnitus

Introduction

Tinnitus is defined as the perception of sound in the head or in the head in the absence of external sounds. The cause of tinnitus is still unknown.

Objective

We aimed to compare the serum levels of total oxidant status, total antioxidant status, serum prolidase enzyme activity and the oxidative stress index in patients with tinnitus to those of normal subjects.

Methods

Twenty five patients with tinnitus (mean age 34.3) and 25 healthy controls (mean age 37.2) were included in the study.

Results

Total oxidant status levels in the patient group were significantly higher than in the control group (p = 0.037). The mean total oxidant status value was 2.54 ± 0.95 mmoL/L in the patient group, and 2.06 ± 0.98 mmoL/L in the control group. The mean oxidative stress index level was 0.22 ± 0.10 AU in the patient group, while it was 0.17 ± 0.08 AU in the control group. Oxidative stress index was significantly higher in the patient group (0.026). There was no significant difference between the groups in terms of total antioxidant status values (p = 0.838). The mean serum prolidase enzyme activity level was 202.74 ± 33.56 U/L in the patient group and 175.46 ± 42.68 U/L in the control group. Serum prolidase enzyme activity levels in the patient group were significantly higher than in the control group (0.040).

Conclusion

We detected that the total oxidant status, oxidative stress index and serum prolidase enzyme activity levels were higher in patients with tinnitus when compared to the healthy controls. This finding suggests that oxidative stress index and serum prolidase enzyme activity may play a role in the etiopathogenesis of tinnitus.

A Comprehensive Study of Oxidative Stress in Tinnitus Patients

Oxidative stress is considered to be one of the molecular changes that are the underlying causes of tinnitus. The aim of this study was to investigate the dynamic thiol/disulphide homeostasis as a new oxidative stress parameter in tinnitus patients as well as to investigate the lipid hydroperoxide (LOOH), total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) parameters and compare the results with the results of the healthy control group. A prospective controlled trial was performed on tinnitus patients in Harran University hospital. A total of 70 subjects, including 35 tinnitus patients and 35 healthy individuals participated in this study. Their total thiol, native thiol levels and LOOH, TAS, TOS levels were measured in plasma of all tinnitus patients and healthy volunteers participants. TOS and OSI levels were significantly increased, and TAS levels were significantly lower in the patient groups compared with the control group (p < 0.01). Native thiol levels and Native thiol/total thiol ratios were significantly lower in the tinnitus group compared to the control group (p < 0.01). Disulphide level and disulphide/native thiol and disulphide/total thiol ratios were significantly higher in the patients (p < 0.01). Also, LOOH ratios were significantly higher in the tinnitus group (p < 0.01). The results of this study reveal that in tinnitus cases, the oxidative stress and antioxidant enzyme imbalance were more significant than in healthy control group. The nature of the relationship between oxidative stress and tinnitus should be clarified with larger studies.

Tinnitus in patients with hearing loss due to mitochondrial DNA pathogenic variants

Purpose

Tinnitus described as individual perception of phantom sound constitutes a significant medical problem and has become an essential subject of many studies conducted worldwide. In the study, we aimed to examine the prevalence of tinnitus among Polish hearing loss (HL) patients with identified mitochondrial DNA (mtDNA) variants.

Methods

Among the selected group of unrelated HL patients with known mtDNA pathogenic variants, two questionnaires were conducted, i.e. Tinnitus Handicap Inventory translated into Polish (THI-POL) and Visual Analogue Scale (VAS) for measuring subjectively perceived tinnitus loudness, distress, annoyance and possibility of coping with this condition (VASs). Pathogenic mtDNA variants were detected with real-time PCR and sequencing of the whole mtDNA.

Results

This is the first extensive tinnitus characterization using THI-POL and VASs questionnaires in HL patients due to mtDNA variants. We have established the prevalence of tinnitus among the studied group at 23.5%. We found that there are no statistically significant differences in the prevalence of tinnitus and its characteristic features between HL patients with known HL mtDNA variants and the general Polish population. In Polish HL patients with tinnitus, m.7511T>C was significantly more frequent than in patients without tinnitus. We observed that the prevalence of tinnitus is lower in Polish patients with m.1555A>G as compared to other available data.

Conclusions

Our data suggest that the mtDNA variants causative of HL may affect tinnitus development but this effect seems to be ethnic-specific.

Serum Oxidative Stress Levels in Patients with Nasal Septal Deviation

Objective

Comparison of the total oxidant status (TOS), total antioxidant status (TAS) and paraoxonase (PON1) serum levels in patients with nasal septum deviation (NSD) and healthy subjects.

Methods

The TAS, TOS, and PON1 serum levels of 47 patients with NSD (mean age 35.3) and 50 healthy subjects (mean age 37.8) were compared in this study.

Results

We found significantly higher TAS levels in the control group (p<0.001). The mean TAS value was 1.196 mmoL/L in the control group, whereas it was 1.046 mmoL/L in the NSD group. On the other hand, TOS was significantly higher in the NSD group (p<0.001). We found that the mean TOS value was 6.600 mmoL/L in the control group, and 20.194 mmoL/L in the NSD group. The NSD and control groups had similar PON1 levels (p=0.446). The mean PON1 value was 279.64 U/L in the control group, and 324.21 U/L in the NSD group.

Conclusion

We detected higher TOS and lower TAS levels in patients with NSD compared to healthy subjects. These results indicate that patients with NSD are exposed to oxidative stress.

Genetics of Tinnitus: Still in its Infancy

Tinnitus is the perception of a phantom sound that affects between 10 and 15% of the general population. Despite this considerable prevalence, treatments for tinnitus are presently lacking. Tinnitus exhibits a diverse array of recognized risk factors and extreme clinical heterogeneity. Furthermore, it can involve an unknown number of auditory and non-auditory networks and molecular pathways. This complex combination has hampered advancements in the field. The identification of specific genetic factors has been at the forefront of several research investigations in the past decade. Nine studies have examined genes in a case-control association approach. Recently, a genome-wide association study has highlighted several potentially significant pathways that are implicated in tinnitus. Two twin studies have calculated a moderate heritability for tinnitus and disclosed a greater concordance rate in monozygotic twins compared to dizygotic twins. Despite the more recent data alluding to genetic factors in tinnitus, a strong association with any specific genetic locus is lacking and a genetic study with sufficient statistical power has yet to be designed. Future research endeavors must overcome the many inherent limitations in previous study designs. This review summarizes the previously embarked upon tinnitus genetic investigations and summarizes the hurdles that have been encountered. The identification of candidate genes responsible for tinnitus may afford gene based diagnostic approaches, effective therapy development, and personalized therapeutic intervention.

A Pilot Genome-Wide Association Study Identifies Potential Metabolic Pathways Involved in Tinnitus

Tinnitus, the perception of an auditory phantom sound in the form of ringing, buzzing, roaring, or hissing in the absence of an external sound source, is perceived by ~15% of the population and 2.5% experiences a severely bothersome tinnitus. The contribution of genes on the development of tinnitus is still under debate. The current manuscript reports a pilot Genome Wide Association Study (GWAS) into tinnitus, in a small cohort of 167 independent tinnitus subjects, and 749 non-tinnitus controls, who were collected as part of a cross-sectional study. After genotyping, imputation, and quality checking, the association between the tinnitus phenotype and 4,000,000 single-nucleotide polymorphisms (SNPs) was tested followed by gene set enrichment analysis. None of the SNPs reached the threshold for genome-wide significance (p < 5.0e–8), with the most significant SNPs, situated outside coding genes, reaching a p-value of 3.4e–7. By using the Genetic Analysis of Complex Traits (GACT) software, the percentage of the variance explained by all SNPs in the GWAS was estimated to be 3.2%, indicating that additive genetic effects explain only a small fraction of the tinnitus phenotype. Despite the lack of genome-wide significant SNPs, which is, at least in part, due to the limited sample size of the current study, evidence was found for a genetic involvement in tinnitus. Gene set enrichment analysis showed several metabolic pathways to be significantly enriched with SNPs having a low p-value in the GWAS. These pathways are involved in oxidative stress, endoplasmatic reticulum (ER) stress, and serotonin reception mediated signaling. These results are a promising basis for further research into the genetic basis of tinnitus, including GWAS with larger sample sizes and considering tinnitus subtypes for which a greater genetic contribution is more likely.