Assessment of reproductive toxicity and genotoxicity of Aconiti Lateralis Radix Praeparata and its processed products in male mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Aconiti Lateralis Radix Praeparata (Chinese name: Fuzi), the root of Aconitum carmichaelii Debx., is a representative medicine for restoring yang and rescuing patient from collapse. However, less studies had been reported on the reproductive toxicity and genotoxicity of Fuzi. According to the principle of reducing toxicity and preserving efficiency, only processed products of Fuzi are commonly applied in clinic, including Baifupian, Heishunpian and Danfupian. However, whether processing could alleviate the reproductive toxicity and genotoxicity of Fuzi had not been revealed. AIM OF THE STUDY: To assess the effect and possible mechanism of Fuzi and its processed products on reproductive toxicity and genotoxicity in male mice. MATERIALS AND METHODS: Aqueous extracts of Fuzi and its processed products (Baifupian, Heishunpian and Danfupian, 5.85 g/kg) were administrated by gavage once daily for fourteen consecutive days. The reproductive toxicity was evaluated by testis weight, testis ratio, testis histopathology, sperm count, sperm viability rate and sperm deformity rate. The genotoxicity was evaluated by comet assay and micronucleus test in sperm, peripheral blood cell and bone marrow cell. Possible mechanisms of attenuating toxicity by processing were analyzed by detecting the level of testosterone, superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA) and catalase (CAT). RESULTS: Fuzi significantly caused different degrees of reproductive toxicity and genotoxicity, specifically reducing the weight and testicular coefficient of testis, causing obvious pathological changes in testicular tissue, reducing sperm count and sperm viability rate, increasing sperm deformity rate and DNA damage in sperm/peripheral blood cells/bone marrow cells. Moreover, Fuzi decreased the level of testosterone, SOD, GSH and CAT, while increased the level of MDA in serum. Notably, the reproductive toxicity and genotoxicity induced by the processed products, especially Heishunpian and Danfupian, were significantly lowered compared to Fuzi. Processing could increase the level of testosterone, SOD, GSH, CAT and decrease the level of MDA compared to Fuzi. CONCLUSION: Fuzi and its processed products had reproductive toxicity and genotoxicity, but the toxicity of processed products was significantly weakened compared to Fuzi. The protective mechanism of processing to reduce the toxicity of Fuzi might be related to increasing the level of testosterone and decreasing oxidative stress.

Optimization of a fast screening method for the assessment of low molecular weight thiols in human blood and plasma suitable for biomonitoring studies.

An adequate level of low molecular weight thiols (LMW-SH, especially glutathione (GSH)) protects cellular macromolecules against toxic agents, and is used as a sensitive biomarker of exposure to toxic compounds. During sample collection, storage and preparation, non-enzymatic and enzymatic oxidation of LMW-SH can occur leading to analytical inaccuracy. The aim of this study was to optimize a fast and reliable screening method for the determination of LMW-SH, mainly GSH, in blood and plasma samples as well as to investigate the impact of storage conditions on the LMW-SH stability. Based on our results, the described spectrophotometric method allows fast and reliable determination of LMW-SH in blood and plasma samples. Results on incubation of samples at 37 °C imply that synthesis of LMW-SH (probably GSH) as well as dynamic interexchange among various thiols forms can be induced in blood cells in in vitro conditions. Importantly, the level of LMW-SH in blood and plasma stored at -20 °C was constant, indicating that they can be stored at -20 °C for at least 30 days. Therefore, the method is suitable for assessment of LMW-SH in long-term human biomonitoring as well as environmental field studies, especially those involving a large number of samples such as epidemiological studies.

Assessment of titanium dioxide nanoparticles toxicity via oral exposure in mice: effect of dose and particle size.

Objective: The aim of the present work is to evaluate the toxicity of titanium dioxide nanoparticles (TiO2NPs) according to their doses and particle sizes. Materials and methods: The effect of five days oral administration of TiO2NPs (21 and 80 nm) with different doses (50, 250 and 500 mg/kg body weight) was assessed in mice via measurement of oxidative stress markers; glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and nitric oxide (NO), liver function indices; aspartate and alanine aminotransferases (AST and ALT), chromosomal aberrations and liver histopathological pattern. Results: The results revealed drastic alterations in all the measured parameters and showed positive correlation with the gradual dose increment. In addition, the smaller particle size of TiO2NPS (21 nm) had more adverse effect in all the selected biochemical parameters, genetic aberrations and histological investigations. Conclusions: Toxicity of TiO2NPs increases in a dose-dependent manner and vice versa with particles size. The evaluated biomarkers are good indicators for TiO2NPs toxicity. More detailed studies are required before the recommendation of TiO2NPS as food additives.

Biomarkers of oxidative stress as an assessment of the redox status of the liver in dogs.

BACKGROUND: Oxidative stress is associated with a diverse group of liver disorders across species. OBJECTIVES: Determine whether glutathione (GSH) concentration in plasma and red blood cells correlates with liver GSH concentration in dogs and evaluate whether other markers of systemic oxidative stress, plasma vitamin E and urine 8-isoprostanes/creatinine (F2 -IsoPs/Cr) concentrations, correlate with liver GSH. ANIMALS: Thirty-four client-owned dogs undergoing clinically indicated liver biopsy and 15 healthy control dogs. METHODS: Prospective, observational cross-sectional study. Urine and blood were collected before liver biopsy. Plasma, erythrocyte, and liver GSH were measured using high performance liquid chromatography (HPLC); vitamin E was measured by HPLC, and F2 -IsoPs/Cr was measured by gas chromatography/mass spectrometry. RESULTS: All dogs were treated at the discretion of the attending clinician (24/34 received antioxidants; 4/34 fed therapeutic liver diet), which included dogs with primary or secondary liver disease (inflammatory (n = 21), metabolic (n = 9), vascular (n = 2), and neoplastic (n = 2)). Median GSH concentrations in plasma, erythrocyte, and liver were 0.18 mg/dL (range 0.14 to 0.56 mg/dL), 56.7 mg/dL (18.3 to 79.2 mg/dL), and 181 mg/dL (39.9 to 527 mg/dL), respectively. No significant correlations were found between liver GSH and erythrocyte GSH, plasma GSH, vitamin E, or F2 -IsoPs/Cr. Dogs undergoing clinically indicated liver biopsy had significantly higher urine F2 -IsoPs/Cr than did healthy controls (5.89 vs 2.98 ng/mg; P < .0001). CONCLUSIONS AND CLINICAL IMPORTANCE: Erythrocyte and plasma GSH are not indicative of liver GSH concentration in dogs. In addition, dogs undergoing clinically indicated liver biopsy have evidence of increased systemic oxidative stress compared to healthy controls.

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.

Fatty acids modulate the efficacy of lutein in cataract prevention: Assessment of oxidative and inflammatory parameters in rats.

BACKGROUND: Effects of lutein (L) and fatty acids [linoleic acid (LA), eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA) and oleic acid (OA)] on oxidative stress and inflammation in cataract were assessed. METHODS: Cataract was induced in male Wistar rat pups (11 days old) by giving a single dose of sodium selenite (25 µM/kg body weight) by IP. Lutein (1.3 µmol/kg body weight) was given one day before and five days after selenite injection as a micelle with 7.5 mM LA, or 7.5 mM EPA + DHA or 7.5 mM OA. Serum and lens oxidative stress and inflammatory parameters having a bearing cataract were assessed. RESULTS: Serum and lens nitric oxide, MDA and protein carbonyls were significantly (p < 0.05) increased in cataract compared to control and experimental groups. Catalase, SOD, glutathione peroxidase and glutathione transferase activity and glutathione level in serum and lens of cataract group were significantly (p < 0.05) decreased. Serum eicosanoids (PGE2, LTB4, and LTC4) and cytokines (CRP, TNF-α, IL1-ß, and MCP-1) were significantly (p < 0.05) increased in cataract. The activity of cPLA2 and Cox-2 in cataract lens was higher (p < 0.05) compared to other groups. EP-1, NOS-2 and NF-kB expression were higher (p < 0.05) in cataract. The ratio of water insoluble to water soluble protein was increased in cataract lens. Group administered with L + EPA + DHA exhibited highest cataract prevention compared to L + LA and L + OA. Pups given lutein with EPA + DHA had the highest amount of lutein in the lens. CONCLUSIONS: The anti-cataract activity of lutein was influenced by fatty acids and found to be highest with EPA + DHA compared to LA or OA.

Assessment of oxidative stress induced by gold nanorods following intra-tracheal instillation in rats.

Gold nanorods (GNRs) are used for their wide variety of applications in various industries. There is a little availability of data related to toxicity and ecological implications of these GNRs. The study evaluated the oxidative stress induction following intra-tracheal instillation of 1 and 5 mg/kg b.w. doses of 10 and 25 nm GNRs by estimating various oxidative stress markers including lipid peroxidation (malondialdehyde; MDA), glutathione (GSH), superoxide dismutase (SOD), catalase and total antioxidant capacity (TAC) after 1 day, 1 week, 1 month, and 3 months post exposure periods. The results have shown increased MDA levels and decreased GSH levels following 1 day and 1 week post exposure periods, indicating induction of oxidative stress. Also, the SOD, catalase and TAC levels were significantly decreased following exposure of both 10 and 25 nm GNRs after 1 day and 1 week after exposures, indicating the inhibition of antioxidant defense mechanisms. Moreover, the 10 nm GNRs at 5 mg/kg dose displayed greater changes in all the estimated parameters, representing dose and size based induction of oxidative stress by GNRs. In contrast, a little change was observed during 1 month and 3 months post exposure periods, may be due to recovery. Finally, the GNRs induced dose-size-dependent oxidative stress induction by various oxidative stress markers following intra-tracheal instillation in rats.

Dynamic and accurate assessment of acetaminophen-induced hepatotoxicity by integrated photoacoustic imaging and mechanistic biomarkers in vivo.

The prediction and understanding of acetaminophen (APAP)-induced liver injury (APAP-ILI) and the response to therapeutic interventions is complex. This is due in part to sensitivity and specificity limitations of currently used assessment techniques. Here we sought to determine the utility of integrating translational non-invasive photoacoustic imaging of liver function with mechanistic circulating biomarkers of hepatotoxicity with histological assessment to facilitate the more accurate and precise characterization of APAP-ILI and the efficacy of therapeutic intervention. Perturbation of liver function and cellular viability was assessed in C57BL/6J male mice by Indocyanine green (ICG) clearance (Multispectral Optoacoustic Tomography (MSOT)) and by measurement of mechanistic (miR-122, HMGB1) and established (ALT, bilirubin) circulating biomarkers in response to the acetaminophen and its treatment with acetylcysteine (NAC) in vivo. We utilised a 60% partial hepatectomy model as a situation of defined hepatic functional mass loss to compared acetaminophen-induced changes to. Integration of these mechanistic markers correlated with histological features of APAP hepatotoxicity in a time-dependent manner. They accurately reflected the onset and recovery from hepatotoxicity compared to traditional biomarkers and also reported the efficacy of NAC with high sensitivity. ICG clearance kinetics correlated with histological scores for acute liver damage for APAP (i.e. 3h timepoint; r=0.90, P<0.0001) and elevations in both of the mechanistic biomarkers, miR-122 (e.g. 6h timepoint; r=0.70, P=0.005) and HMGB1 (e.g. 6h timepoint; r=0.56, P=0.04). For the first time we report the utility of this non-invasive longitudinal imaging approach to provide direct visualisation of the liver function coupled with mechanistic biomarkers, in the same animal, allowing the investigation of the toxicological and pharmacological aspects of APAP-ILI and hepatic regeneration.

Platelets redox balance assessment: Current evidence and methodological considerations.

Altered function of platelets can lead to cardiovascular complications in numerous disorders. Various studies aimed to investigate mechanisms triggering platelets activation cascade show a significant role of reactive oxygen species (ROS) in this matter. Moreover, ROS are known causal factor of oxidative stress that can result in DNA, lipid and protein damage. This review aims to comprehensively present the variety of methods that are potentially useful in assessment of platelets redox balance, such as intracellular concentration of particular ROS, activity of antioxidant enzymes, reduced/oxidized glutathione ratio, level of lipid peroxidation, Cu/Zn ratio, and molecular oxygen consumption. They may help to establish the platelet-related etiological factors in different disorders and to evaluate the antiplatelet therapies. The advantages and limitations of these methods are also discussed. The present paper highlights that clinicians may benefit from implementation of such tools and further encourages developing interdisciplinary evidence-based practice.

Simultaneous assessment of endogenous thiol compounds by LC-MS/MS.

Biological thiol compounds are very important molecules that participate in various physiological events. Alteration in levels of endogenous thiols has been suggested as a biomarker of early stage of pathological changes. We reported a chemical derivatization- and LC-MS/MS-based approach to simultaneously determine thiol compounds including glutathione (GSH), cysteine (Cys), N-acetyl cysteine (NAC), homocysteine (Hcy), and cysteinylglycine (CysGly) in biological samples. Thiol-containing samples were derivatized with monobromobimane (mBrB) at room temperature, followed by LC-MS/MS analysis. Assessment of the analytes with baseline separation was completed within 10min, using a gradient elution on a C18 reversed-phase column. Excellent linearity was observed for all analytes over their concentration ranges of 1-400µM. The lowest limits of detection (S/N=3) in a range from 0.31fmol (for NAC) to 4.98fmol (for CysGly) were achieved. The results indicate that this approach was sensitive, selective, and well suited for high-throughput quantitative determination of the biological thiols.

Can saliva testing replace blood measurements for health monitoring? Insights from a correlation study of salivary and whole blood glutathione in humans.

The feasibility of using saliva samples as diagnostic for health status is assessed. Although blood is regularly used for this purpose, an alternative non-invasive route which yields equivalent clinical information is desirable. The non-invasive saliva testing is validated by comparing its result to that of blood examination. In this investigation, we used glutathione as a paradigmatic example of a biomarker and diagnostic auxiliary. Correlation between the levels of total unbound glutathione, reduced and oxidized, in saliva and whole blood samples from healthy individuals is evaluated. Both salivary and blood glutathione were measured using an enzymatic kinetic assay which was improved to eliminate measurement errors arising from the variation in the enzyme activity from different batches.

Plasma-aminothiols status and inverse correlation of total homocysteine with B-vitamins in arsenic exposed population of West Bengal, India.

Chronic arsenic toxicity is a serious environmental health problem across the world. Bangladesh and India (particularly the state of West Bengal) are the worst affected countries with such problem. The present study reports plasma-aminothiols (p-aminothiols) like L-cysteine (L-Cys), cysteinyl glycine (Cys-gly), total homocysteine (t-Hcy) and glutathione (GSH) status, and the inverse relationship of t-Hcy with B-vitamins (B1, B6, B9 and B12) in arsenic exposed population of West Bengal, India. Reverse phase HPLC was used to measure p-aminothiols and serum B-vitamins in different arsenic exposed population. Arsenic in drinking water and urine were measured by flow injection analysis system - Atomic Absorption Spectrometry (FIAS-AAS) and Transversely heated graphite atomizer (THGA-AAS) techniques, respectively. Water arsenic exposure was >50 µg/L in 50% population, of which majority (33.58%) belong to the range of >50-500 µg/L and more than 8% were even >1000 µg/L. Urine arsenic (µg/g creatinine) levels increased with arsenic exposure. The variability among p-aminothiols was also observed with higher exposure to arsenic in drinking water. A significant difference between exposed and control population was noticed for plasma L-Cys. The difference of B-vitamins between the population exposed to <50 and >50 µg/L arsenic in drinking water was also found to be significant. B9 and B12 deficiency with increased consumption of arsenic in water corroborates the anemic conditions commonly observed among arsenic exposed population. The aminothiol status indicated oxidative stress in exposed population. This study demonstrated progressive increase in plasma t-Hcy as well as inverse relationships of serum B-vitamins with increased water arsenic concentration.

Strategies for High-Quality Nutrition Therapy in Brazil.

Strategies for improving nutrition therapy (NT) are of utmost importance in any healthcare system. The identification and treatment of malnourished patients improves clinical outcome and reduces the length of hospital length of stay and the associated costs. In particular, federal policy regulating the use of NT in Brazil and reimbursement of enteral nutrition (EN) treatment were 2 powerful mechanisms that stimulated the development of nutrition care. Basic and clinical research have also contributed to best practices in NT, thereby highlighting the need for nutrition therapy teams, quality indicators, and nutrition education for the delivery of high-quality NT. It is clear that the availability of training and continuing education programs in clinical nutrition is key to improving nutrition awareness and care, as well as patient outcome. On the basis of our experience, we recommend the Brazilian model as a strategy for improving nutrition care, with appropriate and necessary adaptations made to accommodate different settings.

Assessment of oxidative status in patients with acute kidney injury: a pilot study.

Extensive experimental evidence confirms the role of oxidative stress as a major contributor to the pathogenesis of acute kidney injury (AKI). However, less information is available on the evolution of prooxidant-antioxidant parameters from early to end-phase renal function decline in humans. This study aimed to determine the oxidative status in dynamic throughout the evolutionary phases of the disease. The study included patients with cardiovascular pathology and AKI hospitalized in the intensive care unit (n = 69) and age-matched healthy controls (n = 30). They were followed through three phases of AKI; the first [corrected] phase was the phase of diagnosis, which is characterized by oliguria/anuria, the [corrected] second phase was established diuresis, and the [corrected] third phase was the polyuric phase. In these phases of the disease, blood samples were taken from the patients for biochemical analysis. From the collected whole blood, we measured spectrophotometrically prooxidants: index of lipid peroxidation, measured as Thiobarbituric acid reactive substances (TBARS), nitrite (NO2⁻), superoxide anion radical (O2⁻) and hydrogen peroxide (H2O2), and antioxidants: activity of superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) from erythrocyte lysate. Comparing the results of the three measurements, a significant difference was found in the levels of NO2⁻ and GSH, both of which increased in the second phase (P < 0.05) and then decreased in the third phase, and a significant increase in TBARS, which was elevated in the second phase (P < 0.05) and did not change significantly until the third phase. Our results showed phase-dependent modification in 3 parameters of the oxidative status (TBARS, NO2⁻ and GSH). Whether these changes contribute to the deterioration of renal function in AKI remains to be established.

Application of a new oxidation-reduction potential assessment method in strenuous exercise-induced oxidative stress.

OBJECTIVES: The aim of the study was to test a novel method for assessing oxidative stress, the RedoxSYS™ diagnostic system, a holistic, fast, minimally invasive, and requiring small sample volume method, that measures two parameters, the static (sORP) and the capacity (cORP) oxidation-reduction potential. METHODS: The redox status of 14 athletes participating in a mountain marathon race was assessed. Redox status in blood obtained 1 day before the race and immediately after the race was assessed using the RedoxSYS diagnostic system as well as conventional oxidative stress markers such as glutathione levels (GSH), catalase activity (CAT), thiobarbituric acid reactive substances (TBARS), protein carbonyls (CARB), and total antioxidant activity. RESULTS: The results showed that after the race, the sORP was increased significantly by 7% indicating oxidative stress induction, while cORP was decreased by 14.6% but not significantly. Moreover, the conventional oxidative stress markers GSH and CAT were decreased significantly by 13.1 and 23.4%, respectively, while TBARS and CARB were increased significantly by 26.1 and 15.6%, respectively, after the race indicating oxidative stress induction. DISCUSSION: The present study demonstrated for the first time that the RedoxSYS diagnostic system can be used for evaluating the exercise-induced oxidative stress in athletes.

Astaxanthin from shrimp by-products ameliorates nephropathy in diabetic rats.

AIM: This study investigated the hypoglycemic and antioxidant effects of shrimp astaxanthin on the kidney of alloxan-induced diabetic rats. METHODS: Animals were distributed into four groups of six rats each: a control group (C), a diabetic group (D), a diabetic group supplemented with Astaxanthin (D+As) dissolved in olive oil and a diabetic group supplemented with olive oil (D+OO). In vitro antidiabetic effect was tested in plasma and kidney tissue. RESULTS: The group D of rats showed significant (P < 0.05) increase of glycemia, creatinine, urea and uric acid levels compared to those of the control group (C). Moreover, plasma and kidney malondialdehyde (MDA) and protein carbonyl (PCO) levels for the rats of the group D were significantly increased compared to the control group. Contrariwise, antioxidant enzyme activities, such as catalase (EC 1.11.1.6), superoxide dismutase (EC 1.15.1.1) and non-enzymatic levels of reduced glutathione, were significantly (P < 0.05) decreased in the plasma and kidney of diabetic rats compared to the control ones. The astaxanthin supplementation in rats diet improved the antioxidant enzyme activities and significantly decreased the MDA and PCO levels compared to diabetic rats. Indeed, no significant (P ≥ 0.05) improvement was observed for the fourth group (D+OO) compared to the control group (C). Histological analysis of kidney showed glomerular hypertrophy and tubular dilatation for the diabetic rats. For D+As rats, these histopathological changes were less prominent. CONCLUSIONS: Our results suggest that shrimp astaxanthin may play an important role in reduction of oxidative damage and could prevent pathological changes in diabetic rats suggesting promising application of shrimp astaxanthin in diabet treatment.

[Features of lipid peroxidation-antioxidant protection in adolescent girls in different groups of health].

UNLABELLED: Among the metabolic processes involved in the formation of physical and sexual development of adolescents recently the system of lipid peroxidation and antioxidant protection (LPO-AOP) supporting the redox state of organism and its adaptive response under the influence of different factors is highlighted. BACKGROUND: The aim of this work is an analysis LPO-AOP-parameters in adolescent girls of different groups of health depending on where they live. PATIENTS AND METHODS: We examined 143 girls aged 15-17 years who had the second and the third groups of health and lived in the village and the city. For assessment of LPO-AOP parameters spectrophotometric, spectrofluorometric and statistical methods were used. RESULTS: The combination of high concentration of unsaturated lipids with primary accumulation of lipid peroxidation products and the stable level of the end products of lipid peroxidation were found in girls rural both groups of health. State of the antioxidant defense system in girls of the village was characterized by a high content of its components, except for alpha-tocopherol. It concentration was reduced in girls of the third group of health. The levels of lipid peroxidation secondary intermediats were elevated and oxidized glutathione level was reduced in city girls of the third groups of health. CONCLUSION: The usage of oxidized glutathione for the prevention of exacerbations of chronic diseases in city girls of the third group of health is recommended.

Micro-method for the determination of glutathione in human blood.

A new procedure is described for the visible-range spectrophotometric analysis of glutathione (GSH) in microvolumes of blood (as low as 0.5 µL) collected by fingerstick. Samples are diluted 1 to 300 (v/v) in a stabilizing solution, followed by determination of haemoglobin concentration and by acid deproteination. GSH is then measured in the clear supernatant by colorimetry using DTNB, i.e., 5,5'-dithio-bis(2-nitrobenzoic acid), in aqueous solution at pH 7.8. The DTNB reagent is prepared and kept at pH 6.2 until just prior its addition, thus avoiding spontaneous decomposition of the reagent. The assay is rapid, easy to adapt to large-scale studies and it avoids artefactual oxidation of GSH, a common methodological shortcoming. The method is precise with 1.7 to 3.4% intra-day relative standard deviation (RSD) and 2.2 to 4.2% inter-day RSD, and accurate with -1.4% to 2.3% intra-day relative error (RE) and -2.8% to 1.6% inter-day RE. GSH is recovered by 97.5 to 100% at all tested concentrations. The new colorimetric micro-method was validated by a reliable previously reported HPLC method. The procedure is suitable for minimally invasive investigation of oxidative stress in peripheral blood.

Assessment of plasma aminothiol levels and the association with recurrent atherothrombotic events in patients hospitalized for an acute coronary syndrome: a prospective study.

BACKGROUND: The aminothiols homocysteine and, to a lesser extent, cysteine have been associated with adverse cardiovascular outcome, whereas glutathione, as an antioxidant, may protect against atherosclerosis and thrombosis. Potentially, the combined assessment of these aminothiols may provide a more accurate association with future cardiovascular outcome. We evaluated the association between recurrent atherothrombotic events and the concentration of total plasma cysteine, homocysteine, and glutathione and their combination. METHODS: Respective aminothiols were measured by high-performance liquid chromatography in blood plasma of consecutive first-day survivors admitted for an acute coronary syndrome between April 2002 and January 2004. The combined score was calculated using the combination of the individual aminothiols. The end point was the composite of cardiovascular death, myocardial infarction, and/or stroke. RESULTS: A cohort of 375 consecutive patients (median age 66 years, 66% male) were followed for a median duration of 2.7 years. The end point occurred in 82 patients (22%). In univariate analyses, all aminothiols were significantly associated with the composite end point. After correction for possible confounders, only cysteine and glutathione remained significantly associated. The strongest association with the end point was observed for the combined score (adjusted hazard ratio, 1.40 per standard deviation increase; p=0.005). CONCLUSIONS: Although homocysteine is generally considered the aminothiol of interest with respect to cardiovascular disease, in our prospective study, only cysteine and glutathione appeared independently associated with recurrent atherothrombotic events. Moreover, we showed that an imbalance in the combination of aminothiols could be of more importance than investigating the individual metabolites.

Serum thiols and cardiovascular risk scores: a combined assessment of transsulfuration pathway components and substrate/product ratios.

BACKGROUND: Serum thiols have shown associations with surrogate markers of cardiovascular disease. However, little information is available on their combined association with validated cardiovascular risk scores for primary prevention at population level. We sought to determine whether individual serum thiol concentrations and substrate/product ratios within the transsulfuration pathway are independently associated with such scores. METHODS: Data on clinical and demographic characteristics, serum thiols (homocysteine, cysteine, taurine, glutamylcysteine, total glutathione and cysteinylglycine) and high-sensitivity C-reactive protein (CRP) were collected from a sample of the Hunter Community Study without previous cardiovascular events [n=350, median age (IQR) = 62 (59-66) years]. Five-year absolute cardiovascular risk score for each subject was calculated using the Framingham Risk Equation. RESULTS: Median risk score was 7% (IQR 4-10). After adjusting for body mass index, estimated glomerular filtration rate and physical activity regression analysis showed independent associations between cardiovascular risk scores and a) higher serum homocysteine (B 0.066, 95% CI 0.040 to 0.091, P<0.001) and lower cysteine (B -0.003, 95% CI -0.005 to -0.001, P=0.003) and glutathione (B -0.029, 95% CI -0.056 to -0.003, P=0.03) concentrations; and b) higher homocysteine/cysteine (B 0.114, 95% CI 0.066 to 0.161, P<0.001) and lower glutathione/cysteinylglycine (B -1.145, 95% CI -2.030 to -0.260, P=0.011) ratios. No significant associations were observed between cardiovascular risk scores, taurine and CRP. CONCLUSIONS: Serum homocysteine, cysteine and glutathione are independently associated with cardiovascular risk scores at population level. Enzymatic pathways involved in reduced bioconversion of homocysteine into cysteine and increased glutathione degradation might play an important role in such associations.