Measuring the poise of thiol/disulfide couples in vivo

Sudden Cardiac Death (SCD) - risk stratification and prediction with molecular biomarkers

Sudden cardiac death (SCD) is a sudden, unexpected death that is caused by the loss of heart function. While SCD affects many patients suffering from coronary artery diseases (CAD) and heart failure (HF), a considerable number of SCD events occur in asymptomatic individuals. Certain risk factors for SCD have been identified and incorporated in different clinical scores, however, risk stratification using such algorithms is only useful for health management rather than for early detection and prediction of future SCD events in high-risk individuals. In this review, we discuss different molecular biomarkers that are used for early detection of SCD. This includes genetic biomarkers, where the majority of them are genomic variants for genes that encode for ion channels. Meanwhile, protein biomarkers often denote proteins that play roles in pathophysiological processes that lead to CAD and HF, notably (i) atherosclerosis that involves oxidative stress and inflammation, as well as (ii) cardiac tissue damage that involves neurohormonal and hemodynamic regulation and myocardial stress. Finally, we outline existing challenges and future directions including the use of OMICS strategy for biomarker discovery and the multimarker panels.

Cyclic O3 exposure synergizes with aging leading to memory impairment in male APOE ε3, but not APOE ε4, targeted replacement mice

The etiology of late-onset Alzheimer's disease is unknown. Recent epidemiological studies suggest that exposure to high levels of ozone (O₃) may be a risk factor for late-onset Alzheimer's disease. Nonetheless, whether and how O₃ exposure contributes to AD development remains to be determined. In this study, we tested the hypothesis that O₃ exposure synergizes with the genetic risk factor APOE ε4 and aging leading to AD, using male apolipoprotein E (apoE)4 and apoE3 targeted replacement mice as men have increased risk exposure to high levels of O₃ via working environments and few studies have addressed APOE ε4 effects on males. Surprisingly, our results show that O₃ exposure impairs memory in old apoE3, but not old apoE4 or young apoE3 and apoE4, male mice. Further studies show that old apoE4 mice have increased hippocampal activities or expression of some enzymes involved in antioxidant defense, diminished protein oxidative modification, and neuroinflammation following O₃ exposure compared with old apoE3 mice. These novel findings highlight the complexity of interactions between APOE genotype, age, and environmental exposure in AD development.

Role of native Thiol, total Thiol and dynamic Disulphide in diagnosis of patient with prostate cancer and prostatitis

BACKGROUND

Our study investigates whether Native Thiol, Total Thiol and disulphide levels measured in serum of patients with prostate cancer and prostatitis and of healthy subjects, have any role in differential diagnosis.

MATERIALS AND METHODS

Patients followed up for histopathologically verified diagnosis of prostate cancer and prostatitis in 2016-2017 at the Medicalpark Gaziantep Hospital Urology Clinic were included in the study. Native Thiol (NT), Total Thiol (TT), Dynamic Disulphide (DD) levels in serum were measured by a novel automated method.

RESULTS

NT, TT, DD, NT / TT ratios, DD / TT ratio and DD / NT ratio were measured as 118.4 ± 36.8μmoL / L, 150.3 ± 45.3μmoL / L, 15.9 ± 7μmoL / L, 78.8 ± 7μmoL / L, 10.5 ± 3.5μmoL / L, 13.8 ± 5.8μmoL / L respectively in patients with prostate cancer; as 116.4 ± 40.5μmoL / L, 147.5 ± 50.1μmoL / L, 15.5 ± 8.7μmoL / L, 79.7 ± 9μmoL / L, 10.1 ± 4.5μmoL / L, 13.5 ± 7.2μmoL / L in patients with prostatitis and as 144.1 ± 21.2μmoL / L, 191 ± 32.3μmoL / L, 23.4 ± 10.1μmoL / L, 76.1 ± 98.3μmoL / L, 11.9 ± 4.1μmoL / L, 16.4 ± 6.9μmoL / L in healthy subjects. Significant difference was detected between groups of NT, TT and DD levels (p = 0.008, p = 0.001, p = 0.002). No significant difference was detected in terms of the NT / TT, DD / TT and DD / NT rates (p = 0.222, p = 0.222, p = 0.222).

CONCLUSIONS

Serum NT, TT, DD levels in patients with prostatitis and prostate cancer were found significantly lower compared to the control group. This indicates that just as inflammation, prostate cancer also increases oxidative stress on tissues.

Evaluation of dynamic thiol-disulfide homeostasis in glaucoma patients and the correlation with retinal nerve fiber layer analysis

PURPOSE

The aim of this study was to evaluate thiol/disulfide homeostasis and ischemia-modified albumin levels with primary open-angle glaucoma, ocular hypertension, and control group; also to interpret the correlation between these biochemical parameters and retinal nerve fiber layer analysis.

MATERIAL AND METHODS

In a prospective cross-sectional study, 30 primary open-angle glaucoma cases, 30 ocular hypertension cases, and 30 control subjects were included in the study. Native thiol, total thiol, and disulfide measurements and disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol ratios were evaluated as thiol-disulfide homeostasis. Albumin and ischemia-modified albumin parameters were also evaluated. All cases underwent detailed ophthalmologic examination including visual acuity, retinal nerve fiber layer via optical coherence tomography, intraocular pressure, and central corneal thickness measurements and visual field analysis by 24-2 Swedish Interactive Threshold Algorithm (SITA) Standard visual field test.

RESULTS

Primary open-angle glaucoma group had significantly higher ischemia-modified albumin values than ocular hypertension and control group (p < 0.001). Native thiol and total thiol values of control group were statistically higher than those of primary open-angle glaucoma and ocular hypertension groups. The correlation between the temporal retinal nerve fiber layer value and ischemia-modified albumin, disulfide/native thiol, and disulfide/total thiol values of the primary open-angle glaucoma patients included in the study was moderate correlation in negative direction (r = -0.46, r = -0.39, r = -0.39, respectively), whereas there was a statistically significant moderate correlation in positive direction between the native thiol/total thiol values (r = 0.39) (p < 0.05).

CONCLUSION

These findings have reinforced the role of oxidative stress in the etiopathogenesis of primary open-angle glaucoma, suggesting that the thinning retinal nerve fiber layer may be associated with oxidative stress in favor of prooxidant shift.

Dynamic thiol/disulfide homeostasis in children with community-acquired pneumonia

BACKGROUND

Alteration in thiol level under oxidative stress may contribute to community-acquired pneumonia (CAP). The goal of this study was to determine whether there are changes in thiol/disulfide homeostasis and nitric oxide (NO) in children with CAP.

METHODS

In total, 130 participants were involved in the study. Of these, 65 had been diagnosed with CAP on admission, and the remaining 65 were healthy individuals. Serum total thiol and native thiol were measured in each participant using a novel automated spectrophotometric method. The amount of dynamic disulfide bonds and related ratios were calculated from these values. Serum NO was measured on chemiluminescence assay.

RESULTS

Average native thiol, total thiol, and disulfide in the CAP group were significantly lower than in the healthy individuals (P < 0.0001, P < 0.0001, P = 0.0126, respectively). In addition, disulfide/native thiol (P = 0.0002), and disulfide/total thiol ratios (P = 0.0004) were significantly higher, whereas the native thiol/total thiol ratio (P = 0.0004) was lower in the CAP group. High serum NO was noted in the CAP group (P = 0.0003), but there was no marked correlation between thiol/disulfide and NO.

CONCLUSION

The changes in endogenous thiol levels under oxidative stress may be associated with the pathogenesis of CAP in pediatric patients.

The evaluation of thiol/disulphide homeostasis in diabetic nephropathy

AIMS

Thiol/disulphide homeostasis plays a critical role in antioxidant defense, and detoxification in body. Although alteration of thiol/disulfide homeostasis had been shown in patients with diabetes, the thiol/disulfide balance in patients with type 2 diabetes and nephropathy is not yet known.

METHODS

Twenty-six healthy volunteers (group 1), and 17 normal albuminuric (group 2), 24 middle albuminuric (group 3), 20 severe proteinuric (group 4) patients with type 2 diabetes were included. Proteinuria was tested by measuring microalbumin/creatinine ratio in spot urine. Thiol/disulphide homeostasis concentrations were measured using method developed by Erel et al. RESULTS: Mean blood urea and creatinine levels were found to be significantly higher and GFR level was found to be significantly lower in group 4 than in the other groups. Native thiol levels are significantly lower in groups with diabetes than in healthy group and in groups 3 and 4, compared to group 2. Total thiol level was significantly lower in groups 3 and 4 than group 1 and 2. Disulphide/native thiol and disulfide/total thiol ratios were significantly higher in the groups with diabetes than in group 1 and in the group 4 than in the group 2.

CONCLUSION

The level of native and total thiols were found to be decreased significantly with the grade of nephropathy in patients with type 2 diabetes and the balance had been disrupted in favor of disulphide. We suggest that deteriorated thiol/disulphide balance may be one of the important factors in the development or progression of diabetes induced nephropathy.

Plasma glutathione suggests oxidative stress is equally present in early- and late-onset bipolar disorder

OBJECTIVES

We previously demonstrated oxidative stress in bipolar patients and a relationship between the age of illness onset and total glutathione, a principal antioxidant. In this study, we sought to replicate these findings in a new cohort of patients.

METHODS

We recruited bipolar patients from Warneford Hospital, Oxford, UK, of similar age and grouped them according to age of onset of illness. The early-onset group comprised patients with onset at <23 years, and the late group comprised patients with onset at >30 years. A third group, comprising age-matched healthy volunteers, was also included. Reduced and oxidized glutathione, cysteine, and cystine were determined in plasma, using high-performance liquid chromatography. Mitochondrial DNA copy number, measured in whole blood, was also compared between patients and healthy controls.

RESULTS

Significant increases in oxidative stress were observed in the patient groups, compared with the control group; however, no differences in glutathione-related oxidative stress measures were detected between the early- and late-onset bipolar patient groups. No differences were observed in the amount of mitochondrial DNA, and there was no correlation with mood state.

CONCLUSION

Using a more accurate method to quantify oxidative stress than in our previous study, we show that oxidative stress is a consistent feature of bipolar disorder. Although we did not reproduce our finding correlating age of onset of illness to oxidative stress, we have shown, once again, that oxidative stress is a consistent feature of bipolar disorder.

Thiol/disulfide homeostasis as a marker of oxidative stress in rosacea: a controlled spectrophotometric study

BACKGROUND

Rosacea is the chronic inflammatory disease of the facial skin. Although its aetiology is not clear yet, inflammatory processes triggered by oxidative stress and oxidation of lipids have been suggested to play a role. While studies on the relationship between inflammation and oxidative stress are ongoing, thiol metabolism and its role in oxidative stress have also begun to be investigated. Thiols are among the key molecules of protein metabolism in the organism and they are the firstly consumed antioxidants in case of oxidative stress. Thiols regulate intracellular redox metabolism and protect keratinocytes against the results of oxidative alterations in the stratum corneum. There is a balance known as dynamic thiol/disulfide homeostasis between thiols and their oxidized forms; disulfides.

AIM

This study aimed to determine the effects of oxidative stress on protein metabolism in rosacea patients by investigating thiol/disulfide homeostasis using a newly developed and fully automated method. Determination of plasma thiol levels provides important clues regarding the extent of free radical-mediated oxidation of proteins causing damage in rosacea.

METHODS

The study included 50 rosacea patients who were diagnosed clinically or histopathologically with rosacea and 42 age- and gender-matched healthy controls. Plasma levels of native thiol, total thiol, and disulfide were determined. The following ratios were calculated: disulfide/native thiol ratio, disulfide/total thiol ratio, and native thiol/total thiol ratio.

RESULTS

The mean age was 41.8 ± 10.5 in the rosacea patients (35 females) and 42.5 ± 10.3 years in the control group (33 females). The mean disulfide level was found to be significantly higher in the rosacea patients than in the control group (23.4 ± 5.5 µM/L and 17.3 ± 6.2µM/L, respectively; p < 0.001). The mean disulfide/native thiol ratio (0.055 ± 0.016 vs. 0.041 ± 0.017) and the mean disulfide/total thiol ratio (0.049 ± 0.012 vs.0.037 ± 0.013) were significantly higher and the mean native thiol/total thiol ratio (0.884 ± 0.118 vs. 0.923 ± 0.027) was significantly lower in the patients as compared with the controls (p < 0.05 for all).

CONCLUSION

In rosacea patients, the thiol/disulfide balance was observed to shift towards disulfides, which could be considered an indicator of oxidative stress in rosacea.

Mass Spectrometry in Advancement of Redox Precision Medicine

Redox (portmanteau of reduction-oxidation) reactions involve the transfer of electrons between chemical species in biological processes fundamental to life. It is of outmost importance that cells maintain a healthy redox state by balancing the action of oxidants and antioxidants; failure to do so leads to a multitude of diseases including cancer, diabetes, fibrosis, autoimmune diseases, and cardiovascular and neurodegenerative diseases. From the perspective of precision medicine, it is therefore beneficial to interrogate the redox phenotype of the individual-similar to the use of genomic sequencing-in order to design tailored strategies for disease prevention and treatment. This chapter provides an overview of redox metabolism and focuses on how mass spectrometry (MS) can be applied to advance our knowledge in redox biology and precision medicine.

Effects of antiepileptic drugs on dynamic thiol/disulphide homeostasis in children with idiopathic epilepsy

PURPOSE

Anti-epileptic drugs have been widely used in children with epilepsy. Although several studies have investigated the role of oxidative stress and the effects of antiepileptic drugs on several oxidative markers in epilepsy, adequate information is not available on this issue. This study aimed to investigate the changes in thiol disulphide homeostasis in children with epilepsy under two commonly prescribed AED monotherapies, carbamazepine and valproic acid.

METHODS

A hundred and one children with epilepsy using valproic acid or carbamazepine and 58 healthy children were included in this study. Of the 101 patients with idiopathic epilepsy, 58 were on valproic acid monotherapy and 43 patients were on carbamazepine monotherapy. The total thiol, native thiol, and disulphide levels were measured and the disulphide/native thiol, disulphide/total thiol and native thiol/total thiol ratios were calculated in both groups.

RESULTS

The total thiol and native thiol levels of the valproic acid treated group were significantly lower than the control group (p < 0.05). The native thiol level of carbamazepine treated group was lower than the control group without a significance (p = 0.123). Disulphide level, disulphide/native thiol and disulphide/total thiol ratios were significantly higher and native thiol/total thiol ratio was significantly lower in both valproic acid and carbamazepine treated group compared with the control group.

CONCLUSION

Thiol/disulphide homeostasis is impaired in children with idiopathic epilepsy using valproic acid or carbamazepine. Valproic acid which is frequently used in childhood epilepsy may modify this balance more than carbamazepine monotherapy. More importantly, the new method used in our study proposes a promising, practical and daily applicable test for evaluating oxidative stress in these patien.

A Study Over Thiol Disulfide Homeostasis in Cord Blood in Women With Gestational Diabetes

Objective: To gain insight into the effect of gestational diabetes mellitus (GDM) on cord blood dynamic thiol/disulfide homeostasis. Materials and methods: A prospective case-control study was carried out for 132 pregnant women (62 GDM, 70 controls). The cord blood samples were collected from all the participants, and the native thiol-disulfide exchanges were examined by means of an automated method enabling to measure thiol-disulfide balance. In addition to investigating shifts in thiol disulfide balance between GDM and healthy pregnancies, we sought to correlate the thiol / disulfide homeostasis parameters with other clinical and laboratory characteristics of patients with GDM and using insulin (n = 19) and on a diet only (n = 43). Results: Disulfide amounts, disulfide/native thiol and disulfide/total thiol rates increased (p < 0.001) while native thiol/total thiol decreased in the cord blood of infants born to diabetic mothers (p < 0.001). Furthermore, the patient group administered with insulin and diet only was compared. Disulfide, Disulfide/Native thiol*100, Disulfide/total thiol*100, Native/total thiol*100 differ significantly according to the results (p < 0.05). Disulfide, Disulfide / native thiol * 100, Disulfide/total thiol*100, HbA1c and 75gr are higher than those in patients who do not use insulin. Only Native/total thiol*100 values are higher in patients who use insulin than those who do not. Conclusion: This study suggests that the infants born to diabetic mothers are exposed to increased oxidative stress. In addition, the patients who use insulin better control their blood glucose, thus reducing the need of newborns for intensive care.

Thiol/disulphide homeostasis in manic episode and remission phases of bipolar disorder

PURPOSE

Bipolar disorder (BD) is a chronical psychiatric disorder of which pathophysiology was demonstrated to be related with oxidative stress. Thiol-disulphide homeostasis is an indicator of oxidative balance. This study aims to investigate thiol-disulphide homeostasis in BD.

MATERIALS AND METHODS

27 patients in manic episode (MA), 29 patients in remission (RE) and 60 healthy participants (HC) were included to the study. Serum native thiol and total thiol levels were measured with a novel colorimetric, automated method. The disulphide levels and disulphide/native thiol ratios were also calculated from these measured parameters.

RESULTS

Native thiol levels and total thiol levels of both MA and RE groups were lower than HC. No significant difference detected between MA and RE in terms of native thiol levels and total thiol levels. Disulphide levels and disulphide/native thiol ratio was detected statistically similar between three groups.

CONCLUSION

Our results support the oxidative imbalance theory in pathophysiology of BD. Further studies with larger sample sizes are needed for being able to understand these pathways in detail and use them as a target of treatment.

Dynamic thiol/disulphide homeostasis in acute pancreatitis

BACKGROUND/AIMS

The dynamic thiol/disulfide homeostasis plays pivotal roles in many physiological mechanisms in an organism. We aimed to investigate whether dynamic thiol/disulfide homeostasis changes among patients with acute pancreatitis.

MATERIALS AND METHODS

This prospective trial contained 45 patients with acute pancreatitis and 45 sex-and age-matched healthy volunteers as control group. Thiol/disulfide homeostasis parameters were measured by a novel and automated assay, and detected results were compared between the two groups.

RESULTS

Disulfide/total thiol percent ratio and disulfide/native thiol percent ratios were significantly higher in acute pancreatitis group; besides the native thiol, total thiol levels and native thiol/total thiol percent ratios were significantly lower (for all p < 0.001).

CONCLUSION

The thiol/disulfide homeostasis is impaired in acute pancreatitis with a shift toward the oxidative status, and this deficiency might be a pathogenic factor in acute pancreatitis. The correction of this thiol/disulfide imbalance may be a new target in the management of acute pancreatitis.

Dynamic thiol/disulfide homeostasis in patients with lichen planus

OBJECTIVE

Lichen planus (LP) is an autoimmune inflammatory disease of the mucocutaneous tissue, whose exact pathological course remains unclear. Abnormal thiol/disulfide homeostasis has been postulated to be responsible for a number of diseases predominated by chronic inflammation. To be able to contribute complicated and unclear pathogenesis of LP, we aimed to investigate dynamic thiol/disulfide homeostasis in patients with LP, using an original automated method developed by Erel and Neselioglu in this study.

METHODS

The study group consisted of 81 unrelated patients with LP and 80 unrelated healthy controls with no LP lesions in their personal history or on clinical examination. Thiol/disulphide homeostasis tests have been measured with a novel automatic spectrophotometric method developed and the results have been compared statistically.

RESULTS

Native thiol and total thiol levels were found as significantly higher in patients with LP than the control group (P = 0.026 and 0.035, respectively). There was no significant difference between the disulfide levels of the patients with LP and the control group.

CONCLUSIONS

We provide evidence that that thiol/disulphide homeostasis impaired in favor of thiol levels in LP patients compared to the control group based on the data of our study. To the best of our knowledge, the present study is the first examination on the correlation between thiol and disulfide homeostasis in patients with LP.

Implications of plasma thiol redox in disease

Thiol groups are crucially involved in signaling/homeostasis through oxidation, reduction, and disulphide exchange. The overall thiol pool is the resultant of several individual pools of small compounds (e.g. cysteine), peptides (e.g. glutathione), and thiol proteins (e.g. thioredoxin (Trx)), which are not in equilibrium and present specific oxidized/reduced ratios. This review addresses mechanisms and implications of circulating plasma thiol/disulphide redox pools, which are involved in several physiologic processes and explored as disease biomarkers. Thiol pools are regulated by mechanisms linked to their intrinsic reactivity against oxidants, concentration of antioxidants, thiol-disulphide exchange rates, and their dynamic release/removal from plasma. Major thiol couples determining plasma redox potential (Eh) are reduced cysteine (CyS)/cystine (the disulphide form of cysteine) (CySS), followed by GSH/disulphide-oxidized glutathione (GSSG). Hydrogen peroxide and hypohalous acids are the main plasma oxidants, while water-soluble and lipid-soluble small molecules are the main antioxidants. The thiol proteome and thiol-oxidoreductases are emerging investigative areas given their specific disease-related responses (e.g. protein disulphide isomerases (PDIs) in thrombosis). Plasma cysteine and glutathione redox couples exhibit pro-oxidant changes directly correlated with ageing/age-related diseases. We further discuss changes in thiol-disulphide redox state in specific groups of diseases: cardiovascular, cancer, and neurodegenerative. These results indicate association with the disease states, although not yet clear-cut to yield specific biomarkers. We also highlight mechanisms whereby thiol pools affect atherosclerosis pathophysiology. Overall, it is unlikely that a single measurement provides global assessment of plasma oxidative stress. Rather, assessment of individual thiol pools and thiol-proteins specific to any given condition has more solid and logical perspective to yield novel relevant information on disease risk and prognosis.

The effect of the modes of delivery on the maternal and neonatal dynamic thiol-disulfide homeostasis

Background: Thiols are organic compounds containing sulfhydryl groups which exert antioxidant effects via dynamic thiol-disulfide homeostasis. The shift towards disulfide indicates the presence of oxidative environment. The thiol-disulfide homeostasis has not been studied in different mode of delivery before. Aims: To investigate the effects of mode of parturition on the thiol-disulfide homeostasis in mothers and term infants. Study design: The participants were grouped according to the mode of their delivery: group vaginal delivery (VD, n = 40) and group cesarean section (C/S, n = 40). Three serum samples were collected: from mothers at the beginning of labor, from the cord blood (CB), and from the infants at the 24th hour after birth. The dynamic thiol-disulfide homeostasis in both groups were compared. Results: The levels of native-thiol and total-thiol in CB were significantly higher in VD group than those with C/S group. The levels of disulfide were higher in infants born by C/S compared with those born by VD. The disulfide-to-native thiol ratio, disulfide-to-total thiol ratio, and native thiol-to-total thiol ratio were similar between two groups. Conclusion: Our results showed that the dynamic thiol-disulfide homeostasis of the neonate was greatly influenced by the way of delivery and supported that vaginally delivered infants have less oxidative stress.

Association Between Living in Food Deserts and Cardiovascular Risk

BACKGROUND

Food deserts (FD), neighborhoods defined as low-income areas with low access to healthy food, are a public health concern. We evaluated the impact of living in FD on cardiovascular risk factors and subclinical cardiovascular disease (CVD) with the hypothesis that people living in FD will have an unfavorable CVD risk profile. We further assessed whether the impact of FD on these measures is driven by area income, individual household income, or area access to healthy food.

METHODS AND RESULTS

We studied 1421 subjects residing in the Atlanta metropolitan area who participated in the META-Health study (Morehouse and Emory Team up to Eliminate Health Disparities; n=712) and the Predictive Health study (n=709). Participants' zip codes were entered into the United States Food Access Research Atlas for FD status. Demographic data, metabolic profiles, hs-CRP (high-sensitivity C-reactive protein) levels, oxidative stress markers (glutathione and cystine), and arterial stiffness were evaluated. Mean age was 49.4 years, 38.5% male and 36.6% black. Compared with those not living in FD, subjects living in FD (n=187, 13.2%) had a higher prevalence of hypertension and smoking, higher body mass index, fasting glucose, and 10-year risk for CVD. They also had higher hs-CRP (P=0.014), higher central augmentation index (P=0.015), and lower glutathione level (P=0.003), indicative of increased oxidative stress. Area income and individual income, rather than food access, were associated with CVD risk measures. In a multivariate analysis that included food access, area income and individual income, both low-income area and low individual household income, were independent predictors of a higher 10-year risk for CVD. Only low individual income was an independent predictor of higher hs-CRP and augmentation index.

CONCLUSIONS

Although living in FD is associated with a higher burden of cardiovascular risk factors and preclinical indices of CVD, these associations are mainly driven by area income and individual income rather than access to healthy food.

Evaluation of the level of dynamic thiol/disulphide homeostasis in adolescent patients with newly diagnosed primary hypertension

BACKGROUND

Thiol/disulphide homeostasis plays a critical role in numerous intracellular enzymatic pathways including antioxidant defense and detoxification. This study was designed to investigate the impact of thiol/disulfide homeostasis in adolescent patients with recently diagnosed primary hypertension (HT) using a novel and automated method.

METHODS

Native thiol/disulphide levels were measured by a novel spectrophotometric method (Cobasc 501, Roche Diagnostics, Mannheim, Germany) in 30 patients with primary HT together with 30 healthy controls.

RESULTS

The levels of native thiol, total thiol, and native thiol/total thiol ratios were significantly lower, while the disulphide level, disulphide/native thiol, and disulphide/total thiol ratios were significantly higher in patients with primary HT compared with the control group. There were significant positive correlations between 24-h mean systolic and diastolic blood pressure and disulphide levels, disulphide/native thiol, and disulphide/total thiol ratios. A multiple linear regression model showed that a disulphide/native thiol ratio above 5 and family history of HT are independent predictors of HT.

CONCLUSIONS

Our study showed that dynamic thiol/disulphide homeostasis shifted towards disulphide formation in adolescent patients with primary HT. Understanding the role of thiol/disulfide homeostasis in primary HT might provide new therapeutic intervention strategies for patients.

Thiol/disulphide homeostasis in bipolar disorder

Bipolar disorder (BD) patients have increased oxidative stress, which can disturb thiol/disulphide homeostasis, causing disulphide formation. The aim of the study is to investigate dynamic thiol/disulphide (SH/SS) homeostasis in BD patients, which is a novel evaluation method of oxidative status. Ninety-four BD patients (50 in the manic episode and 44 in remission) and 44 healthy controls were included in the study. Blood serum native thiol (SH) and total thiol (ToSH) concentrations were measured in a paired test. The half value of the difference between native thiol and total thiol concentrations was calculated as the disulphide (SS) bond amount. Serum native thiol levels of the mania group were found to be lower than the remission and the control groups. There was a significant difference between the remission group and the control group in terms of native thiol. Serum total thiol level was lower in mania group than the control group. Detection of oxidative molecules for BD could be helpful, especially in treatment, follow-up periods and reducing morbidity. The results of our study besides the data available in the literature support that thiol and disulphide levels are useful markers for BD and promising therapeutic targets in terms of future pharmacological modulation.

Thiol Disulfide Homeostasis in Schizophrenic Patients Using Atypical Antipsychotic Drugs

Objective

Schizophrenia is a severe, debilitating mental disorder characterized by behavioral abnormalities. Although several studies have investigated the role of oxidative stress and the effects of antipsychotic drugs on oxidative markers in schizophrenia, adequate information is not available on these issues. The aim of this study is to determine the changes in oxidative status and thiol disulfide homeostasis in schizophrenic patients using atypical antipsychotic drugs.

Methods

Thirteen schizophrenic patients using atypical antipsychotic drugs and 30 healthy controls were included this study. The concentrations of total oxidant status (TOS), total antioxidant status (TAS), native thiol, total thiol, and disulfide levels were determined in the study population.

Results

The TAS (p=0.001), total thiol, and native thiol levels (p<0.001) were higher in the patients compared to the controls, whereas the TOS and disulfide levels were lower in the patients than in the controls (p<0.001).

Conclusion

These results may suggest that atypical antipsychotic drugs have a useful therapeutic effect by reducing oxidative stress via the inhibition of the formation of disulfide bonds. The study population number was one of the limitations of this study. Therefore, further studies are needed to establish the association between thiol disulfide homeostasis in schizophrenic patients using atypical antipsychotic drugs.

A robust and versatile mass spectrometry platform for comprehensive assessment of the thiol redox metabolome

Several diseases are associated with perturbations in redox signaling and aberrant hydrogen sulfide metabolism, and numerous analytical methods exist for the measurement of the sulfur-containing species affected. However, uncertainty remains about their concentrations and speciation in cells/biofluids, perhaps in part due to differences in sample processing and detection principles. Using ultrahigh-performance liquid chromatography in combination with electrospray-ionization tandem mass spectrometry we here outline a specific and sensitive platform for the simultaneous measurement of 12 analytes, including total and free thiols, their disulfides and sulfide in complex biological matrices such as blood, saliva and urine. Total assay run time is < 10 min, enabling high-throughput analysis. Enhanced sensitivity and avoidance of artifactual thiol oxidation is achieved by taking advantage of the rapid reaction of sulfhydryl groups with N-ethylmaleimide. We optimized the analytical procedure for detection and separation conditions, linearity and precision including three stable isotope labelled standards. Its versatility for future more comprehensive coverage of the thiol redox metabolome was demonstrated by implementing additional analytes such as methanethiol, N-acetylcysteine, and coenzyme A. Apparent plasma sulfide concentrations were found to vary substantially with sample pretreatment and nature of the alkylating agent. In addition to protein binding in the form of mixed disulfides (S-thiolation) a significant fraction of aminothiols and sulfide appears to be also non-covalently associated with proteins. Methodological accuracy was tested by comparing the plasma redox status of 10 healthy human volunteers to a well-established protocol optimized for reduced/oxidized glutathione. In a proof-of-principle study a deeper analysis of the thiol redox metabolome including free reduced/oxidized as well as bound thiols and sulfide was performed. Additional determination of acid-labile sulfide/thiols was demonstrated in human blood cells, urine and saliva. Using this simplified mass spectrometry-based workflow the thiol redox metabolome can be determined in samples from clinical and translational studies, providing a novel prognostic/diagnostic platform for patient stratification, drug monitoring, and identification of new therapeutic approaches in redox diseases.

A New Classification System for IgG4 Autoantibodies

IgG4 autoimmune diseases are characterized by the presence of antigen-specific autoantibodies of the IgG4 subclass and contain well-characterized diseases such as muscle-specific kinase myasthenia gravis, pemphigus, and thrombotic thrombocytopenic purpura. In recent years, several new diseases were identified, and by now 14 antigens targeted by IgG4 autoantibodies have been described. The IgG4 subclass is considered immunologically inert and functionally monovalent due to structural differences compared to other IgG subclasses. IgG4 usually arises after chronic exposure to antigen and competes with other antibody species, thus "blocking" their pathogenic effector mechanisms. Accordingly, in the context of IgG4 autoimmunity, the pathogenicity of IgG4 is associated with blocking of enzymatic activity or protein-protein interactions of the target antigen. Pathogenicity of IgG4 autoantibodies has not yet been systematically analyzed in IgG4 autoimmune diseases. Here, we establish a modified classification system based on Witebsky's postulates to determine IgG4 pathogenicity in IgG4 autoimmune diseases, review characteristics and pathogenic mechanisms of IgG4 in these disorders, and also investigate the contribution of other antibody entities to pathophysiology by additional mechanisms. As a result, three classes of IgG4 autoimmune diseases emerge: class I where IgG4 pathogenicity is validated by the use of subclass-specific autoantibodies in animal models and/or in vitro models of pathogenicity; class II where IgG4 pathogenicity is highly suspected but lack validation by the use of subclass specific antibodies in in vitro models of pathogenicity or animal models; and class III with insufficient data or a pathogenic mechanism associated with multivalent antigen binding. Five out of the 14 IgG4 antigens were validated as class I, five as class II, and four as class III. Antibodies of other IgG subclasses or immunoglobulin classes were present in several diseases and could contribute additional pathogenic mechanisms.

Higher Mediterranean Diet Quality Scores and Lower Body Mass Index Are Associated with a Less-Oxidized Plasma Glutathione and Cysteine Redox Status in Adults

Background

Both systemic redox status and diet quality are associated with risk outcomes in chronic disease. It is not known, however, the extent to which diet quality influences plasma thiol/disulfide redox status.

Objective

The purpose of this study was to investigate the influence of diet, as measured by diet quality scores and other dietary factors, on systemic thiol/disulfide redox status.

Methods

We performed a cross-sectional study of 685 working men and women (ages ≥18 y) in Atlanta, GA. Diet was assessed by 3 diet quality scores: the Alternative Healthy Eating Index (AHEI), Dietary Approaches to Stop Hypertension (DASH), and the Mediterranean Diet Score (MDS). We measured concentrations of plasma glutathione (GSH), cysteine, their associated oxidized forms [glutathione disulfide (GSSG) and cystine (CySS), respectively], and their redox potentials (EhGSSG and EhCySS) to determine thiol/disulfide redox status. Linear regression modeling was performed to assess relations between diet and plasma redox after adjustment for age, body mass index (BMI), sex, race, and history of chronic disease.

Results

MDS was positively associated with plasma GSH (β = 0.02; 95% CI: 0.003, 0.03) and total GSH (GSH + GSSG) (β = 0.02; 95% CI: 0.003, 0.03), and inversely associated with the CySS:GSH ratio (β = -0.02; 95% CI: -0.04, -0.004). There were significant independent associations between individual MDS components (dairy, vegetables, fish, and monounsaturated fat intake) and varying plasma redox indexes (P < 0.05). AHEI and DASH diet quality indexes and other diet factors of interest were not significantly correlated with plasma thiol and disulfide redox measures.

Conclusion

Adherence to the Mediterranean diet was significantly associated with a favorable plasma thiol/disulfide redox profile, independent of BMI, in a generally healthy working adult population. Although longitudinal studies are warranted, these findings contribute to the feasibility of targeting a Mediterranean diet to improve plasma redox status.

Impaired thiol-disulphide homeostasis in patients with axonal polyneuropathy

OBJECTIVE

The objective of this study is to examine thiol-disulphide homeostasis in patients with polyneuropathy dominated by diabetic or non-diabetic axonal degeneration.

MATERIALS-METHODS

Fifty-four patients diagnosed with polyneuropathy dominated by axonal damage and 41 healthy subjects were included in the study. The patients were grouped into two groups according to whether or not they had diabetes. The native thiol and total thiol concentrations were measured with the newly developed automated method.

RESULTS

While there was no significant difference between the patients with diabetic and non-diabetic polyneuropathy in terms of native thiol and total thiol levels (p > 0.05), the native thiol and total thiol levels of the groups with both diabetic polyneuropathy and non-diabetic polyneuropathy were significantly low compared to the control group (p < 0.01). The level of disulphides in the patients with diabetic polyneuropathy was significantly higher than that of the patients with non-diabetic polyneuropathy and the healthy individuals (p < 0.05). The loss in the sural nerve sensory neural action potential amplitude was positively correlated with the decrease in the levels of both native thiol and total thiol (p < 0.05).

DISCUSSION

In our study, we observed that the thiol-disulphide balance was also impaired in patients with non-diabetic polyneuropathy similar to patients with diabetic polyneuropathy, and we therefore considered that impaired the thiol-disulphide homeostasis could be the last common path in patients with polyneuropathy with axonal damage, regardless of the aetiology. Therefore, fortification of thiol deficiency with N-acetyl cysteine or alpha-lipoic acid can fix the thiol-disulphide balance and help decelerate the axonal damage.

Oxidative stress predicts cognitive decline with aging in healthy adults: an observational study

Background

Redox signaling, which can be assessed by circulating aminothiols, reflects oxidative stress (OS) status and has been linked to clinical cardiovascular disease and its risk factors. These, in turn, are related to executive function decline. OS may precede the pro-inflammatory state seen in vascular disease. The objective of this study is to investigate the association between aminothiol markers of OS and inflammation in cognitive decline, especially in the executive cognitive domain which is highly susceptible to cardiovascular risk factors and is an important predictor of cognitive disability.

Methods

The study design is that of a longitudinal cohort study within the setting of a large academic institution with participants being university employees (n = 511), mean age 49 years, 68% women, and 23% African-American. These participants were followed for four consecutive years with a yearly cognitive assessment conducted using computerized versions of 15 cognitive tests. Peripheral cystine, glutathione, their disulfide derivatives, and C-reactive protein (CRP) were measured.

Results

Lower levels of glutathione at baseline was associated with a decline in the executive domain over 4 years (covariate-adjusted relative risk (RR) for glutathione = 1.70 (95% CI = 1.02–2.85), p = 0.04). Furthermore, a longitudinal decline in glutathione level was associated with a faster decline in the executive domain (p = 0.03). None of the other OS markers or CRP were linked to cognitive decline over 4 years.

Conclusion

Increased OS reflected by decreased glutathione was associated with a decline in executive function in a healthy population. In contrast, inflammation was not linked to cognitive decline. OS may be an earlier biomarker that precedes the inflammatory phase of executive decline with aging.

Vitamin D deficiency is associated with an oxidized plasma cysteine redox potential in critically Ill children

Critically ill populations incur high levels of oxidative stress and commonly present with vitamin D deficiency. This study aimed to investigate the relationship between vitamin D status and plasma markers of glutathione (GSH) and cysteine (Cys) redox and immunity in critically ill children. This was a cross-sectional study of n=50 PICU patients. Subjects were categorized according to their plasma 25-hydroxyvitamin D [25(OH)D] concentrations: (<20, 20-30, and ≥30ng/dL). Plasma GSH, glutathione disulfide (GSSG), Cys, and cystine (CySS) were measured with high-performance liquid chromatography, and their associated redox potentials determined (E_hGSSG and E_hCySS, respectively). Plasma LL-37, an indicator of innate immune function, was assayed with ELISA. Data were analyzed using general linear regression before and after adjustment for age, sex, and race. Results showed that E_hCySS was more reduced in subjects with plasma 25(OH)D concentrations ≥30ng/mL compared to those with 25(OH)D concentrations <20ng/mL (P=0.009). Plasma GSH, GSSG, and total GSH decreased with increasing 25(OH)D category (P=0.06, 0.03, and 0.01, respectively), and plasma glutamine levels were lowest in subjects with plasma 25(OH)D concentrations ≥30ng/mL (P=0.004). Plasma LL-37 concentrations did not significantly differ by vitamin D status (P=0.08). In conclusion, vitamin D sufficiency was associated with more reduced plasma E_hCySS, indicative of lower oxidative stress in critically ill children. Plasma GSH, GSSG, and glutamine, however, were lower in the vitamin D sufficient group. The role of vitamin D in maintaining redox status during pediatric critical illness requires further study.

Dynamic Thiol/Disulphide Homeostasis in Children and Adolescents with Non-Autoimmune Subclinical Hypothyroidism

OBJECTIVE

To evaluate the thiol/disulphide homeostasis in children with non-autoimmune subclinical hypothyroidism (SHT).

SUBJECTS AND METHODS

Thiol/disulphide homeosta sis, involving native thiol (SH), disulphide (SS), and total thiol (SS + SH), was evaluated in 60 children and adolescents who were negative for thyroid auto-antibodies (anti-thyroid peroxidase, anti-thyroglobulin) and had a thyroid-stimulating hormone (TSH) value of > 5 mIU/L, and in 40 sex- and age-matched healthy control subjects who were negative for thyroid autoantibodies and had normal TSH levels. Lipid profiles and urine iodine levels were also determined.

RESULTS

SH (466 ± 32.8 vs. 462 ± 32.1 μmol/L p = 0.59), SH + SS (508 ± 34.0 vs. 506 ± 32.7 μmol/L, p = 0.81), SS (21 ± 5.5 vs. 22 ± 5.8 μmol/L, p = 0.41), SS/SH (4.5 ± 1.2 vs. 4.8 ± 1.3%, p = 0.36), SS/SH + SS (4.1 ± 1.0 vs. 4.3 ± 1.1%, p = 0.36) and SH/SH + SS (91 ± 2.1 vs. 91 ± 2.1%, p = 0.31) levels were similar in children with SHT and control subjects (p > 0.05). There was no difference between total cholesterol, triglyceride, and low-density lipoprotein levels in SHT patients and controls. No difference was detected between the patients with or without iodine deficiency in the SHT group in terms of thiol/disulphide homeostasis parameters.

CONCLUSION

The status of dynamic thiol/disulphide homeostasis did not change in children and adolescents with non-autoimmune SHT. Future studies are needed for the evaluation of oxidative stress in patients with long-standing non-autoimmune SHT.

Oxidative stress in critically ill ventilated adults: effects of vitamin D3 and associations with alveolar macrophage function

Background

Disruptions in redox balance lead to oxidative stress, a promoter of morbidity in critical illness. This study aimed to: 1) characterize the plasma and alveolar thiol/disulfide redox pools, 2) examine their associations with alveolar macrophage phagocytosis, and 3) determine the effect of high dose vitamin D₃ on plasma thiol/disulfide redox.

Methods

Subjects were 30 critically ill, ventilated adults in a double-blind randomized trial of high-dose (250 000 or 500 000 IU) vitamin D₃ or placebo. Baseline bronchoalveolar lavage fluid (BALF) samples were analyzed for determination of alveolar phagocytosis index (PI) and for concentrations of glutathione (GSH), glutathione disulfide (GSSG), cysteine (Cys), cystine (CySS), and their respective redox potentials (EhGSSG and EhCySS). Plasma redox outcomes were assessed at baseline and days 7 and 14.

Results

Baseline plasma Cys was inversely associated with alveolar PI (ρ = −0.69, P=0.003), and E_hCySS was positively associated with PI (ρ = 0.61, P=0.01). Over time, among all subjects there was an increase in plasma GSH levels and a decrease in E_hGSSG (P<0.01 for both), with no difference by treatment group. Vitamin D₃ decreased oxidized plasma GSSG to a more normal state (P for group × time=0.009).

Conclusions

Oxidative stress indicators were positively associated with alveolar macrophage phagocytic function in acutely ill ventilated adults. High-dose vitamin D₃ decreased plasma GSSG concentrations, which suggests that vitamin D can possibly improve the oxidative stress environment.

Biomarkers to Predict Cardiovascular Death

This article reviews biomarkers that have been shown to identify subjects at increased risk for cardiovascular death within the general population, in those with established coronary artery disease, and in those with heart failure. Use of biomarkers for risk stratification for sudden cardiac death continues to evolve. It seems that a multimarker strategy for risk stratification using simple measures of circulating proteins and usual clinical risk factors, particularly in patients with known coronary artery disease, can be used to identify patients at near-term risk of death. Whether similar strategies in the general population will prove to be cost-effective needs to be investigated.

Relation of Changes in Body Fat Distribution to Oxidative Stress

Android fat is a surrogate measure of visceral obesity in the truncal region. Both visceral adiposity and oxidative stress (OS) are linked to cardiometabolic risk factors and clinical cardiovascular disease. However, whether body fat distribution (android vs gynoid) is associated with OS remains unknown. We hypothesized that increased android fat will be associated with greater OS. Body fat distribution and markers of OS, including plasma levels of reduced (cysteine and glutathione) and oxidized (cystine and glutathione disulfide) aminothiols, were estimated in 711 volunteers (67% female, 23% black, mean age 48 ± 11) enrolled in the Emory Georgia Tech Predictive Health study. At 1 year, 498 subjects had repeat testing. At baseline, anthropometric and fat distribution indexes, including body mass index, waist circumference, weight/hip ratio, and android and gynoid fat mass correlated with lower plasma concentrations of glutathione and higher cystine levels indicative of higher OS. At 1 year, the change in android but not gynoid fat mass or body mass index negatively correlated with the change in the plasma glutathione level after adjustment for cardiovascular risk factors. Increased body fat, specifically android fat mass, is an independent determinant of systemic OS, and its change is associated with a simultaneous change in OS, measured as plasma glutathione. In conclusion, our findings suggest that excess android or visceral fat contributes to the development of cardiovascular disease through modulating OS.

Evaluation of dynamic thiol-disulfide homeostasis in very low-birth-weighted preterms

BACKGROUND

Thiols are organic compounds containing sulfhydryl groups which exert antioxidant effects via dynamic thiol-disulfide homeostasis. The shift towards disulfides indicates the presence of oxidative environment. Thiol-disulfide homeostasis has not been evaluated in neonates. We aimed to evaluate dynamic thiol-disulfide homeostasis in preterm infants.

METHODS

Preterm infants with birth weight less than 1500 g (25-32 weeks of gestation) were included. Infants with major congenital anomaly, perinatal asphyxia, twin to twin transfusion and infants who were mechanically ventilated and nil by mouth for more than 3 days or fed with formula, had intraventricular hemorrhage ≥ grade 2 or sepsis, received blood/blood product transfusion or inotrope treatment and developed bronchopulmonary dysplasia or retinopathy of prematurity (≥ stage 3), and died were excluded thereafter. Serum thiol-disulfide homeostasis was evaluated for three times: (Baseline, first week, third week). Serum native thiol, total thiol and disulfide were measured (µmol/Lt), disulfide:native thiol, disulfide:total thiol, and native thiol:total thiol ratios were calculated. Wilcoxon's test was used to analyze the significance of change in measurements. Baseline results were analyzed for gender and mode of delivery.

RESULTS

Eighty preterm infants [1255 (1080-1415) grams] were included. Baseline values were native thiol: 209.54 ± 41.83 µmol/L; total thiol: 251.70 ± 45.82 µmol/L; disulfide: 21.08 ± 7.43 µmol/Lt; disulfide:native thiol: 10.49 ± 4.62; disulfide:total thiol: 8.45 ± 2.93; native thiol:total thiol: 83.10 ± 5.87. Thiol levels increased in each measurement, disulfide and disulfide/thiol ratios increased in the first week, decreased in the third week, ratio of native/total thiol decreased in the first week, increased in the third week. No effect of gender or mode of delivery on baseline thiol-disulfide homeostasis was detected.

CONCLUSIONS

The shift in the thiol-disulfide equilibrium towards disulfides in the first week can be attributed to subjection of infants to many oxidative insults. Furthermore, the thiol predominance in the third week could be explained by the decrease in oxidative events and increase in feeding as a supply of antioxidants. This study, displaying the levels of the dynamic thiol-disulfide homeostasis in preterm infants without obvious risks for increased oxidative stress, may provide acceptable range for thiol-disulfide homeostasis in recovering preterm infants.

Dynamic thiol disulphide homeostasis in operating theater personnel exposed to anesthetic gases

BACKGROUND

The purpose of this study was to investigate the association between dynamic thiol/disulphide homeostasis and occupational exposure to volatile anesthetic gases in operating theater personnel. Decreased blood thiol levels and raised blood disulphide levels serve as biomarkers of oxidative stress.

METHODS

We included 65 subjects occupationally exposed and 55 unexposed healthy medical professionals into the study. A novel method enabled separate measurements of components involved in dynamic thiol/disulphide homeostasis (native thiol, disulphide, and total thiol). To control for the potential confounding effect on oxidative stress of psychological symptoms potentially caused by occupational stress, we used scores obtained from four different anxiety and depression inventories.

RESULTS

Mean ± standard deviation native thiol was found to be 433.35 ± 30.68 in the exposed group, lower than among controls, 446.61 ± 27.8 (P = 0.02). Disulphide in the exposed group was 15.78 ± 5.12, higher than among controls, 12.14 ± 5.33 (P < 0.001). After adjusting for anxiety and depression scores, age and gender, native thiol remained lower and disulphide higher in the exposed group (P = 0.008 and P < 0.001).

CONCLUSION

Dynamic thiol/disulphide homeostasis in workers exposed to anesthetic gases was found to be disturbed after adjusting for the possible contribution of anxiety. We infer that this is due to the oxidative effect of exposure to anesthetic gases.

Association between oxidative stress and atrial fibrillation

BACKGROUND

Oxidative stress (OS) may be a key mechanism underlying the development of atrial fibrillation (AF) in experimental studies, but data in humans remain limited.

OBJECTIVE

Systemic OS can be estimated by measurements of circulating levels of the aminothiols including glutathione, cysteine, and their oxidized products. We tested the hypothesis that the redox potentials of glutathione (E_hGSH) and cysteine will be associated with prevalent and incident AF.

METHODS

Plasma levels of aminothiols were measured in 1439 patients undergoing coronary angiography, of whom 148 (10.3%) had a diagnosis of AF. After a median follow-up of 6.3 years, 104 of 917 patients (11.5%) developed incident AF. Multivariate logistic regression and Cox regression models were used to determine whether OS markers were independent predictors of prevalent and incident AF after adjustment for traditional risk factors, heart failure, coronary artery disease, and high-sensitivity C-reactive protein level.

RESULTS

For each 10% increase in E_hGSH, the odds of prevalent AF was 30% higher (odds ratio [OR] 1.3; 95% confidence interval [CI] 1.1-1.7; P = .02) and 90% higher (OR 1.9; 95% CI 1.3-2.7; P = .004) when the median was used as a cutoff. The E_hGSH level above the median was more predictive of chronic AF (OR 4.0; 95% CI 1.3-12.9; P = .01) than of paroxysmal AF (OR 1.7; 95% CI 1.1-2.7; P = .03). Each 10% increase in E_hGSH level was associated with a 40% increase in the risk of incident AF (hazard ratio 1.4; 95% CI 1.1-1.7; P = .01).

CONCLUSION

Increased OS measured by the redox potentials of glutathione is associated with prevalent and incident AF. Therapies that modulate OS need to be investigated to treat and prevent AF.

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.

Thiol/disulphide homeostasis in celiac disease

AIM

To determine dynamic thiol/disulphide homeostasis in celiac disease and to examine the associate with celiac autoantibodies and gluten-free diet.

METHODS

Seventy three patients with celiac disease and 73 healthy volunteers were enrolled in the study. In both groups, thiol/disulphide homeostasis was examined with a new colorimetric method recently developed by Erel and Neselioglu.

RESULTS

In patients with celiac disease, native thiol (P = 0.027) and total thiol (P = 0.031) levels were lower, while disulphide (P < 0.001) level, disulphide/native thiol (P < 0.001) and disulphide/total thiol (P < 0.001) ratios were higher compared to the control group. In patients who do not comply with a gluten-free diet, disulphide/native thiol ratio was found higher compared to the patients who comply with the diet (P < 0.001). In patients with any autoantibody-positive, disulphide/native thiol ratio was observed higher compared to the patients with autoantibody-negative (P < 0.05). It is found that there is a negative correlation between celiac autoantibodies, and native thiol, total thiol levels and native thiol/total thiol ratio, while a positive correlation is observed between disulphide, disulphide/native thiol and disulphide/total thiol levels.

CONCLUSION

This study is first in the literature which found that the patients with celiac disease the dynamic thiol/disulphide balance shifts through disulphide form compared to the control group.

Investigation of dynamic thiol-disulphide homoeostasis in age-related cataract patients with a novel and automated assay

PURPOSE

The aim of this study was to determine plasma thiol-disulphide homoeostasis in patients with age-related cataract (ARC) and compare the results of the patients with healthy subjects. Plasma malondialdehyde (MDA) levels and catalase (CAT) activity were also investigated.

METHODS

The study included 53 cataract patients and 52 healthy volunteers. Native thiol-disulphide exchanges were determined using a novel and automated method. CAT activity was determined using the method described by Aebi, and MDA levels were calculated using the thiobarbituric acid method.

RESULT

Native thiol and total thiol levels were significantly lower in the cataract patients compared with the controls (p < 0.001, p = 0.002, respectively). The disulphide levels of the cataract patients were significantly higher than the controls (p = 0.002). The ratios of disulphide/native thiol and disulphide/total thiol were statistically higher in the cataract patients compared with the control group (p < 0.001, p < 0.001, respectively). Furthermore, CAT activity was significantly lower in the cataract patient group compared with the control group (p < 0.001), and MDA levels were insignificantly higher in the patient group (p = 0.581).

CONCLUSIONS

Our study showed that dynamic thiol-disulphide homoeostasis has shifted towards disulphide formation, as a result of thiol oxidation in ARC patients. The present study is the first to measure thiol-disulphide homoeostasis in ARC patients with a novel automated assay. This study supports the hypothesis that cataract is an oxidative disorder. Further studies are required in order to examine the relationship between oxidative stress and the development of cataract formation.

Preventive and therapeutic application of molecular hydrogen in situations with excessive production of free radicals

Excessive production of oxygen free radicals has been regarded as a causative common denominator of many pathological processes in the animal kingdom. Hydroxyl and nitrosyl radicals represent the major cause of the destruction of biomolecules either by a direct reaction or by triggering a chain reaction of free radicals. Scavenging of free radicals may act preventively or therapeutically. A number of substances that preferentially react with free radicals can serve as scavengers, thus increasing the internal capacity/activity of endogenous antioxidants and protecting cells and tissues against oxidative damage. Molecular hydrogen (H(2)) reacts with strong oxidants, such as hydroxyl and nitrosyl radicals, in the cells, that enables utilization of its potential for preventive and therapeutic applications. H(2) rapidly diffuses into tissues and cells without affecting metabolic redox reactions and signaling reactive species. H(2) reduces oxidative stress also by regulating gene expression, and functions as an anti-inflammatory and anti-apoptotic agent. There is a growing body of evidence based on the results of animal experiments and clinical observations that H(2) may represent an effective antioxidant for the prevention of oxidative stress-related diseases. Application of molecular hydrogen in situations with excessive production of free radicals, in particular, hydroxyl and nitrosyl radicals is relatively simple and effective, therefore, it deserves special attention.

Evaluation of Dynamic Disulphide/Thiol Homeostasis in Silica Exposed Workers

BACKGROUND

Oxidative stress is implicated as one of the main molecular mechanism underlying silicosis.

AIMS

In this study, our aim was to asses the redox status in occupationally silica-exposed workers, by evaluating the dynamic thiol-disulphide homeostasis.

STUDY DESIGN

Case-control study.

METHODS

Thirty-six male workers occupationally exposed to silica particles and 30 healthy volunteers, working as office workers were included to the study. Posteroanterior chest radiographs and pulmonary function tests of both groups were evaluated. Also serum thiol disulphide levels were measured using the spectrophotometric method described by Erel and Neşelioğlu.

RESULTS

Among the 36 workers that underwent pulmonary function tests 6 (17%) had obstructive, 7 (19%) had restrictive, 6 (17%) had obstructive and restrictive signs whereas 17 (47%) had no signs. The mean PFTs results of silica-exposed workers were significantly lower than control subjects. The serum disulphide levels of silica-exposed workers were significantly higher than control subjects (23.84±5.89 μmol/L and 21.18±3.44 μmol/L, respectively p=0.02).

CONCLUSION

The serum disulphide levels, a biomarker of oxidative stress, are found to be higher in silica-exposed workers.

Thiol/disulfide homeostasis in postmenopausal osteoporosis

AIM

To evaluate the impact of postmenopausal osteoporosis on thiol/disulfide homeostasis.

MATERIALS AND METHODS

A total of 75 participants were divided into two groups: Group 1 (n = 40) was composed of healthy postmenopausal women, and group 2 (n = 35) was composed of women with postmenopausal osteoporosis. Clinical findings and thiol/disulfide homeostasis were compared between the two groups.

RESULTS

The disulfide/native thiol ratio was 8.6% ± 3.6 in group 1 and 12.7% ± 8.4 in group 2 (p = 0.04). The disulfide/native thiol percent ratio was significantly higher in group 2 after adjustment for the years since menopause and age (p < 0.05). The native thiol/total thiol percent ratio was 85.6% ± 4.8 in group 1 and 73.8% ± 24.9 in group 2 (p = 0.01). The native thiol/total thiol percent ratio was significantly lower in group 2 after adjustment for the years since menopause and age (p < 0.05).

CONCLUSION

Thiol/disulfide homeostasis shifted to the disulfide side independent of age and years since menopause in postmenopausal osteoporosis.

Pediatric Multiple Organ Dysfunction Syndrome: Promising Therapies

OBJECTIVE

To describe the state of the science, identify knowledge gaps, and offer potential future research questions regarding promising therapies for children with multiple organ dysfunction syndrome presented during the Eunice Kennedy Shriver National Institute of Child Health and Human Development Workshop on Pediatric Multiple Organ Dysfunction Syndrome (March 26-27, 2015).

DATA SOURCES

Literature review, research data, and expert opinion.

STUDY SELECTION

Not applicable.

DATA EXTRACTION

Moderated by an expert from the field, issues relevant to the association of multiple organ dysfunction syndrome with a variety of conditions were presented, discussed, and debated with a focus on identifying knowledge gaps and research priorities.

DATA SYNTHESIS

Summary of presentations and discussion supported and supplemented by relevant literature.

CONCLUSIONS

Among critically ill children, multiple organ dysfunction syndrome is relatively common and associated with significant morbidity and mortality. For outcomes to improve, effective therapies aimed at preventing and treating this condition must be discovered and rigorously evaluated. In this article, a number of potential opportunities to enhance current care are highlighted including the need for a better understanding of the pharmacokinetics and pharmacodynamics of medications, the effect of early and optimized nutrition, and the impact of effective glucose control in the setting of multiple organ dysfunction syndrome. Additionally, a handful of the promising therapies either currently being implemented or developed are described. These include extracorporeal therapies, anticytokine therapies, antitoxin treatments, antioxidant approaches, and multiple forms of exogenous steroids. For the field to advance, promising therapies and other therapies must be assessed in rigorous manner and implemented accordingly.

A novel tool reflecting the role of oxidative stress in the cataracts: thiol/disulfide homeostasis

We investigated serum and aqueous humor thiol/disulfide (T-D) homeostasis in patients with cataracts versus healthy controls. In total, 56 patients with cataracts and 49 healthy controls were enrolled in this case-control study. Serum total thiol (TT), native thiol (NT), and disulfide (DS) concentrations were determined using a novel automated measurement method. Additionally, DS/TT, DS/NT and NT/TT percentage ratios were compared between the groups. In comparison with the control group, serum NT levels and aqueous humor TT and NT levels were significantly lower (p < .05, p < .05 and p < .001, respectively), whereas serum and aqueous humor DS levels were significantly higher in cataract patients (p < .01 and p < .001). DS/TT and DS/NT ratios were significantly higher and the NT/TT ratio was lower in cataract patients in serum (p < .005) and aqueous humor samples (p < .001). In conclusion, serum T-D homeostasis may be useful as biochemical markers, indicating the role of oxidative stress in the development of cataracts. Further studies are needed to confirm the pathophysiological role of T-D homeostasis in cataractogenesis.

Dynamic thiol/disulfide homeostasis in children with attention deficit hyperactivity disorder and its relation with disease subtypes

BACKGROUND

The aim of this study was to evaluate a novel oxidative stress marker (thiol/disulfide homeostasis) in attention deficit hyperactivity disorder (ADHD) children for the first time in literature.

METHODS

Ninety children with ADHD diagnosed according to DSM-V and as control group, 65 healthy children were included to the study. Native thiol, total thiol, disulfide, disulfide/native thiol, disulfide/total thiol were compared between the groups.

RESULTS

Total and native thiol levels were significantly higher whereas the disulfide/native thiol ratios were significantly lower in children with ADHD. ADHD combined type appeared to have higher disulfide, disulfide/native thiol and disulfide/total thiol ratios compared to other subtypes. Disulfide levels of the males with ADHD were significantly higher than those of the females with ADHD.

CONCLUSION

This study suggests that thiol/disulfide homeostasis is abnormal in children with ADHD. It may be used as a novel OS marker in ADHD children because it is easy, practical, fully automated and relatively inexpensive.