Thiol/disulphide homeostasis as a novel indicator of oxidative stress in sudden sensorineural hearing loss

How can nanomicelle-curcumin modulate aluminum phosphide-induced neurotoxicity?: Role of SIRT1/FOXO3 signaling pathway

Aluminum phosphide (ALP) is among the most significant causes of brain toxicity and death in many countries. Curcumin (CUR), a major turmeric component, is a potent protective agent against many diseases, including brain toxicity. This study aimed to examine the probable protection potential of nanomicelle curcumin (nanomicelle-CUR) and its underlying mechanism in a rat model of ALP-induced brain toxicity. A total of 36 Wistar rats were randomly divided into six groups (n = 6) and exposed to ALP (2 mg/kg/day, orally) + CUR or nanomicelle-CUR (100 mg/kg/day, orally) for 7 days. Then, they were anesthetized, and brain tissue samples were dissected to evaluate histopathological alterations, oxidative stress biomarkers, gene expression of SIRT1, FOXO1a, FOXO3a, CAT and GPX in brain tissue via hematoxylin and eosin (H&E) staining, biochemical and enzyme-linked immunosorbent assay (ELISA) methods and Real-Time PCR analysis. CUR and nanomicelle-CUR caused significant improvement in ALP-induced brain damage by reducing the MDA levels and induction of antioxidant capacity (TTG, TAC and SOD levels) and antioxidant enzymes (CAT, GPX), modulation of histopathological changes and up-regulation of gene expression of SIRT1 in brain tissue. It was concluded that nanomicelle-CUR treatment ameliorated the harmful effects of ALP-induced brain toxicity by reducing oxidative stress. Therefore, it could be considered a suitable therapeutic choice for ALP poisoning.

MiR-106a facilitates the sensorineural hearing loss induced by oxidative stress by targeting connexin-43

Sensorineural hearing loss (SNHL) is a common clinical side effect resulted from the overusing of aminoglycoside antibacterial drugs, such as gentamicin. Oxidative stress is recently evidenced to be an important inducer for SNHL, which is reported to be associated with the knockdown of connexin-43. MiR-106a is recently found as a regulator of connexin-43. The present study aims to investigate whether miR-106a is a vital mediator in the development of SNHL. Firstly, upregulated miR-106a was observed in the peripheral blood sample of SNHL patients. Glucose oxidase (GO) was utilized to induce oxidative injury in isolated rat cochlear marginal cells (MCs), followed by introducing the miR-106a inhibitor. We found that the declined proliferation ability, increased apoptosis, and activated oxidative stress in GO-stimulated MCs were dramatically abolished by the miR-106a inhibitor, accompanied by the upregulation of connexin-43. The targeting correlation between miR-106a and connexin-43 was predicted and confirmed by the dual luciferase gene reporter assay. Furthermore, the regulatory effect of miR-106a inhibitor against the proliferation, apoptosis, and oxidative stress in GO-treated MCs were dramatically abolished by the knockdown of connexin-43. Gentamicin was utilized to establish the SNHL model in rats, followed by the treatments of antagomir-106a and antagomir-106a combined with carbenoxolone, an inhibitor of connexin-43. The alleviated pathological state, reduced apoptosis, and ameliorated oxidative stress in cochlea tissues were observed in antagomir-106a treated SNHL rats, which were dramatically reversed by the co-administration of carbenoxolone. Collectively, miR-106a facilitated the SNHL induced by oxidative stress via targeting connexin-43.

Effects of general anaesthesia and ultrasonography-guided interscalene block on pain and oxidative stress in shoulder arthroscopy: A randomised trial

BACKGROUND/AIM

The aim of this study was to evaluate the effects of general anaesthesia and ultrasonography-guided interscalene block on pain and oxidative stress evaluated by thiol-disulphide balance and C-reactive protein levels in patients undergoing shoulder arthroscopy.

MATERIALS AND METHODS

A total of 42 patients aged 18-75 years who were scheduled to undergo shoulder arthroscopy were randomised into interscalene block group (Group-IB, n = 20) and general anaesthesia group (Group-GA, n = 22). All patients received patient-controlled analgesia during the postoperative period. Additional analgesics were administered to patients with a visual analogue scale score of >4. Native-thiol, total-thiol, disulphide and C-reactive protein levels were measured. Patients' visual analogue scale scores, morphine and additional analgesic consumption were recorded. A shift in thiol-disulphide balance towards decreased thiol and increased disulphide levels was regarded as an indicator of oxidative stress.

RESULTS

Pain level, morphine and additional analgesic consumption were higher in Group-GA. Native-thiol and total-thiol levels were higher in Group-IB postoperatively and also disulphide levels were lower at postoperative 18 hours. C-reactive protein levels were similar in both the groups.

CONCLUSION

Interscalene block induced less oxidative stress during the postoperative period, as evaluated by thiol-disulphide balance. In shoulder arthroscopy, interscalene block provides more stable haemodynamics perioperatively and facilitates better postoperative pain control.

The efficacy of adenotonsillectomy on oxidative stress evaluated by thiol / disulfide balance

BACKGROUND

Oxidative stress plays a role in the pathogenesis of many chronic diseases. Upper airway obstruction has been identified as a risk factor for increased oxidative stress-related disorders such as obstructive sleep apnea. The effect of adenotonsillar hypertrophy, which may result in a narrowing of the upper airways, on oxidative stress can be a valuable subject of research. This study aimed to investigate the efficacy of adenotonsillectomy on oxidative stress evaluated using the thiol / disulfide balance.

METHODS

Thirty children who underwent adenotonsillectomy and 30 healthy controls, all aged from 3 to 18 years, were included in the study. Blood samples were taken preoperatively and 3 months postoperatively in the study group; in the control group, baseline blood samples were taken and samples were again taken 3 months later. Thiol / disulfide homeostasis items were analyzed. Antioxidant markers were native thiol, total thiol, and native / total thiol. Oxidative stress markers were disulfide, disulfide / native thiol, and disulfide / total thiol.

RESULTS

At the preoperative period, oxidative stress parameters of thiol / disulfide homeostasis were higher in the study group than in the control group (P < 0.05) and antioxidant activity parameters were lower than in the control group (P < 0.05). Three months postoperatively, oxidative stress parameters were lower than in the control group (P < 0.05), and antioxidant parameters were no different from those in the control group (P > 0.05). In the adenotonsillectomy group considered separately, oxidative stress markers of disulfide and disulfide / native thiol decreased (P < 0.05) and antioxidant markers of native thiol and total thiol increased in the postoperative measurements (P < 0.05).

CONCLUSIONS

Oxidative stress related to adenotonsillar hypertrophy decreased after adenotonsillectomy. The antioxidant parameters of the thiol homeostasis increased after adenotonsillectomy. We concluded that adenotonsillectomy operations should be planned and applied timeously to prevent the adverse effects of adenotonsillar hypertrophies on thiol homeostasis.

The relationship between thiol-disulfide balance and idiopathic sudden sensorineural hearing loss

Introduction

Impaired cochlear perfusion is a major etiological factor in idiopathic sudden sensorineural hearing loss. Oxidative stress has been shown to be a risk factor for oxidative damage.

Objectives

We investigated the role of oxidative stress in idiopathic sudden sensorineural hearing loss by comparing serum levels of oxidant and antioxidant molecules including thiol/disulfide homeostasis paraoxonase, stimulated thiol/disulfide homeostasis paraoxonase, arylesterase, ceruloplasmin and myeloperoxidase in patients who did and did not recover after treatment.

Methods

The amount of dynamic disulfide was calculated by determining half of the difference between the total thiols and native thiols. After the determination of native, total thiol, and disulfide amounts, the disulfide/total thiol percent ratio, native thiol/total thiol ratio and disulfide/native thiol percent ratio were calculated and then compared between the two groups. Additionally, clinical relationship between audiological recovery and native thiol, disulfide, disulfide/native thiol percent ratio, and disulfide/total thiol percent ratio levels was investigated. Blood samples were also analyzed for the assessment of thiol/disulfide homeostasis paraoxonase, stimulated thiol/disulfide homeostasis paraoxonase, arylesterase, ceruloplasmin, and myeloperoxidase levels.

Results

A significant difference was found between the two groups with regard to total oxidant status disulfide, disulfide/native thiol percent ratio, disulfide/total thiol percent ratio, and native thiol/total thiol ratio levels (p =  0.001, p =  0.001, p =  0.001, p =  0.003, p =  0.001, p =  0.002, respectively). However, no significant difference was found between the two groups with regard to thiol/disulfide homeostasis paraoxonase, stimulated thiol/disulfide homeostasis paraoxonase, ceruloplasmin, and myeloperoxidase levels (p >  0.05 for all).

Conclusion

The results supported the common hypothesis that vascular pathologies are the primary cause of idiopathic sudden sensorineural hearing loss and that other etiological factors ultimately result in vascular pathologies. The oxidant-antioxidant and thiol-disulfide balances were impaired in the idiopathic sudden sensorineural hearing loss group.

Compensatory Paraoxonase and Arylesterase Levels in Hyperbaric Oxygen Treatment of Sudden Sensorineural Hearing Loss

Objective: Paraoxonase1 (PON1) and Arylesterase (ARE) levels are associated with reduced risk of atherosclerosis. The functional status of high density lipoprotein (HDL) is closely related to the PON1/ARE enzyme activity. Functional changes in treatment of sudden sensorineural hearing loss (SSNHL) may be achieved by post-translational modification of lipid metabolism induced by hyperbaric oxygen therapy (HBOT).

Methods: Men patients with SSNHL who met the research criteria were included in the study. HBOT was performed on average 30 sessions. Laboratory measurements were made at the beginning and end of HBOT for the same patients. Serum levels of PON1/ARE and routine lipid laboratory parameters were measured to determine possible changes in SSNHL after HBOT.

Results: In this study, a reducing effect on PON1 enzyme amount of long-term HBOT was detected. The serum PON1 amount of patients with SSNHL was 19.7 ± 2.7 ng / mL (mean ± SD) before HBOT, and the serum PON1 decreased to 17.0 ± 2.1 ng / mL (mean ± SD) after 30 sessions of HBOT. This decrease in PON1 levels was statistically significant (p =0.035). There was also a statistically significant decrease in the enzyme activity of ARE in the SSNHL patients (p=0.024).

Conclusion: This preliminary study showed a significant decrease in serum PON1/ARE enzyme content in SSNLH patients with HBOT. In fact, it can be assumed that HBOT has no adverse effect on HDL functionality. However, the decrease in PON1 level by HBOT with 30 or more sessions may be important for the antioxidant function of HDL.It may possibly cause post-translational changes in antioxidant defense mechanisms due to increased oxidative stress with HBOT. In conclusion, larger clinical studies are needed to determine the possible effects of HBOT on HDL-related PON1/ARE functionality in SSNHL.

Assessment of Oxidative Stress in Patients with Sudden Hearing Loss: A Non-randomized Prospective Clinical Study

The etiology of sudden hearing loss (SHL) has not been fully elucidated. Previous studies claimed that different etiological factors may play a role in the pathogenesis of SHL. The aim of the present study is to investigate the presence of oxidative stress (OS) in SHL cases using thiol-disulfide balance. In addition, total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI) and lipid hydroperoxide levels (LOOH) were investigated. A total of 30 cases (15 female, 15 male, mean age 48.9 ± 8.1 years, age range: 36-68 years) were included in the study. Thiol and disulfide amounts, thiol/disulfide ratios, TOS, TAS, OSI and LOOH scores of the case group and control group were compared. Native thiol (SH) and total thiol (SH + SH) values were significantly lower in the SHL group than in the control group (p = 0.028 and p = 0.044, respectively). The LOOH value, TOS value and OSI value were significantly higher in the SHL group than in the control group (all p values < 0.05). The TAS value was significantly lower in the SHL group than in the control group (p = 0.0001). The present study has presented that the thiol-disulfide balance was impaired in SHL cases. OS may play a role in the development of SHL.

Oxidative Status in Patients with Benign Paroxysmal Positional Vertigo

OBJECTIVE

Benign paroxysmal positional vertigo (BPPV) is the most frequent peripheral vestibular disorder and is particularly seen among older patients suffering from vertigo. The brief vertigo attacks in and imbalance symptoms of BPPV are caused by freely floating otoconia within the semicircular canals. The aim of this prospective study was to evaluate the role of oxidative stress, using native thiol/disulfide (SH/SS) homeostasis as a novel indicator, in the etiology of BPPV.

MATERIALS AND METHODS

The 62 participants in the study included 31 patients with BPPV and, as the control group, 31 healthy individuals without any cochleovestibular disorders.

RESULTS

Patients with BPPV initially had significantly lower native SH levels and significantly lower SH/total thiol (TT) ratios, as well as significantly higher SS/SH and SS/TT ratios, than the healthy controls. After successful treatment of their vertigo, which was confirmed based on the results obtained from the second blood sample, patients with BPPV still had lower SH levels and SH/TT ratios and significantly higher SS/SH and SS/TT ratios than the healthy controls.

CONCLUSION

Our results suggest a role of oxidative stress in the development of BPPV, through both calcium metabolism and the direct toxic effects of free oxygen radicals, including the triggering of apoptosis.

Decreased disulphide/thiol ratio in patients with autosomal recessive non-syndromic hearing loss

INTRODUCTION

Oxidative stress plays a key role in the formation of age-related, noise-induced and drug-induced hearing loss. Thiols are organic compounds which can react with free radicals to protect against tissue and cell damage caused by reactive oxygen. There are no studies in literature on the association between autosomal recessive non-syndromic hearing loss(ARNSHL) including GJB2 and non-GJB2 mutations and thiol-disulphide balance. In this study, we aim to assess whether thiol-disulphide balance is disrupted in patients with ARNSHL.

METHODS

Thirty-one ARNSHL patients and thirty-one healthy controls were included in this study. Patients whose parents were first degree cousins and who had at least two congenital hearing loss in the same family were included in the study. Audiological tests included air - bone pure tone audiometry and auditory brain stem response. GJB2 gene analysis was performed using sanger sequence method. Tests of thiol/disulphide homeostasis were conducted using the automated spectrophotometric method. We first investigated whether there was a significant difference between ARNSHL patients and healthy controls. Then, in order to determine the differential effect of the GJB2 gene mutations and non-GJB2 gene mutations on the thiol-disulphide balance, subjects were divided into three groups: Group 1 included patients with GJB2 mutations; Group 2 included patients with non-GJB2 mutations; Group 3 included healthy subjects.

RESULTS

Patients with ARNSHL had significantly higher native thiol (411.6 ± 54.3 μmol/l vs. 368.0 ± 64.3 μmol/l, p = 0.006), total thiol levels (440.3 ± 56.2 μmol/l vs. 402.4 ± 65.9 μmol/l, p = 0.018), and lower disulphide levels (14.3 ± 5.7 μmol/l) vs. (17.1 ± 4.9 μmol/l), (p = 0.043) compared to the control group. Moreover, disulphide /native thiol (p < 0.001) and disulphide/total thiol (p < 0.001) were also detected lower in the ARNSHL group compared to the control group. Thiol-disulphide hemostasis parameters between all three groups showed that the native thiol and total thiol were increased in the Group 1 and Group 2. The disulphide levels decreased in Group 1 and 2, although not statistically significant.

CONCLUSION

It was shown that thiol levels increased and disulphide levels decreased in patients with autosomal recessive non-syndromic hearing loss. It also may suggest that there is a reverse association between ARNSHL and oxidative stress. Further studies are needed on whether or not ARNSHL cause oxidative stress limited to the inner ear and cochlea.

Total serum bilirubin levels and sensorineural hearing loss in the US adolescents: NHANES 2007-2010

OBJECTIVE

We aimed to investigate whether current levels of total serum bilirubin are associated with different subtypes of sensorineural hearing loss (SNHL) in adolescents.

METHODS

A set of cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) (2007-2010) was used. A subset of 1404 adolescents was sampled for measurements of total serum bilirubin, tympanometry, and average pure tone threshold at low-frequencies (LPTA: 500, 1000, 2000 Hz) or high-frequencies (HPTA: 3000, 4000, 6000, and 8000 Hz). SNHL was defined as the hearing loss that had type A tympanograms with a peak admittance of 0.3 ml or greater. Associations between serum bilirubin (square-root transformed) and different subtypes of SNHL were evaluated using binary or multinomial logistic regression models with 4-year sampling weights. The bootstrap method was used for estimation of variance and 10-fold cross-validation for assessment of overfitting issue.

RESULTS

Total serum bilirubin levels were found to be associated with any high-frequency (HPTA>15 dB in at least one ear, adjusted odds-ratio (OR_a)(bootstrap 95% confidence interval) = 3.29(1.31-8.19), p = 0.011), but not with any low-frequency (LPTA>15 dB in at least one ear), SNHL in the US adolescents. Furthermore, high-frequency SNHL with HPTA>15 dB in both ears (bilateral) or HPTA≥25 dB in at least one ear, compared to that with HPTA>15 dB in one ear only (unilateral) or HPTA = 15-25 dB in at least one ear, had a stronger association with total serum bilirubin levels (OR_a = 5.37(1.27-22.65), p = 0.022 for bilateral; OR_a = 2.64(0.84-8.25), p = 0.094 for unilateral; OR_a = 5.00(0.95-26.58), p = 0.058 for HPTA≥25 dB in at least one ear; as well as OR_a = 3.06(1.15-8.25), p = 0.025 for HPTA = 15-25 dB in at least one ear). No severe overfitting problems were found.

CONCLUSION

Our findings suggest that current levels of total serum bilirubin may be informative in predicting and/or targeting high-frequency SNHL in the US adolescents.

Redox theory of aging: implications for health and disease

Genetics ultimately defines an individual, yet the phenotype of an adult is extensively determined by the sequence of lifelong exposures, termed the exposome. The redox theory of aging recognizes that animals evolved within an oxygen-rich environment, which created a critical redox interface between an organism and its environment. Advances in redox biology show that redox elements are present throughout metabolic and structural systems and operate as functional networks to support the genome in adaptation to environmental resources and challenges during lifespan. These principles emphasize that physical and functional phenotypes of an adult are determined by gene-environment interactions from early life onward. The principles highlight the critical nature of cumulative exposure memories in defining changes in resilience progressively during life. Both plasma glutathione and cysteine systems become oxidized with aging, and the recent finding that cystine to glutathione ratio in human plasma predicts death in coronary artery disease (CAD) patients suggests this could provide a way to measure resilience of redox networks in aging and disease. The emerging concepts of cumulative gene-environment interactions warrant focused efforts to elucidate central mechanisms by which exposure memory governs health and etiology, onset and progression of disease.

Brain Metabolic Changes in Rats following Acoustic Trauma

Acoustic trauma is the most common cause of hearing loss and tinnitus in humans. However, the impact of acoustic trauma on system biology is not fully understood. It has been increasingly recognized that tinnitus caused by acoustic trauma is unlikely to be generated by a single pathological source, but rather a complex network of changes involving not only the auditory system but also systems related to memory, emotion and stress. One obvious and significant gap in tinnitus research is a lack of biomarkers that reflect the consequences of this interactive "tinnitus-causing" network. In this study, we made the first attempt to analyse brain metabolic changes in rats following acoustic trauma using metabolomics, as a pilot study prior to directly linking metabolic changes to tinnitus. Metabolites in 12 different brain regions collected from either sham or acoustic trauma animals were profiled using a gas chromatography mass spectrometry (GC/MS)-based metabolomics platform. After deconvolution of mass spectra and identification of the molecules, the metabolomic data were processed using multivariate statistical analysis. Principal component analysis showed that metabolic patterns varied among different brain regions; however, brain regions with similar functions had a similar metabolite composition. Acoustic trauma did not change the metabolite clusters in these regions. When analyzed within each brain region using the orthogonal projection to latent structures discriminant analysis sub-model, 17 molecules showed distinct separation between control and acoustic trauma groups in the auditory cortex, inferior colliculus, superior colliculus, vestibular nucleus complex (VNC), and cerebellum. Further metabolic pathway impact analysis and the enrichment overview with network analysis suggested the primary involvement of amino acid metabolism, including the alanine, aspartate and glutamate metabolic pathways, the arginine and proline metabolic pathways and the purine metabolic pathway. Our results provide the first metabolomics evidence that acoustic trauma can induce changes in multiple metabolic pathways. This pilot study also suggests that the metabolomic approach has the potential to identify acoustic trauma-specific metabolic shifts in future studies where metabolic changes are correlated with the animal's tinnitus status.