Fluorine-thiol displacement probes for acetaminophen's hepatotoxicity

Chemicals possessing reactive electrophiles can denature innate proteins leading to undesired toxicity, and the overdose-induced liver injury by drugs containing electrophiles has been one of the major causes of non-approval and withdraw by the US Food and Drug Administration (FDA). Elucidating the associated proteins could guide the future development of therapeutics to circumvent these drugs' toxicities, but was largely limited by the current probing tools due to the steric hindrance of chemical tags including the common "click chemistry" labels. Taking the widely used non-steroidal anti-inflammatory drug acetaminophen (APAP) as an example, we hereby designed and synthesized an APAP analogue using fluorine as a steric-free label. Cell toxicity studies indicated our analogue has similar activity to the parent drug. This analogue was applied to the mouse hepatocellular proteome together with the corresponding desthiobiotin-SH probe for subsequent fluorine-thiol displacement reactions (FTDRs). This set of probes has enabled the labeling and pull-down of hepatocellular target proteins of the APAP metabolite as validated by Western blotting. Our preliminary validation results supported the interaction of APAP with the thioredoxin protein, which is an important redox protein for normal liver function. These results demonstrated that our probes confer minimal steric perturbation and mimic the compounds of interest, allowing for global profiling of interacting proteins. The fluorine-thiol displacement probing system could emerge as a powerful tool to enable the investigation of drug-protein interactions in complex biological environments.

Preparation of silk fibroin/hyaluronic acid composite hydrogel based on thiol-ene click chemistry / 浙江大学学报·医学版

OBJECTIVES@#To design and prepare silk fibroin/hyaluronic acid composite hydrogel.@*METHODS@#The thiol modified silk fibroin and the double-bond modified hyaluronic acid were rapidly cured into gels through thiol-ene click polymerization under ultraviolet light condition. The grafting rate of modified silk fibroin and hyaluronic acid was characterized by 1H NMR spectroscopy; the gel point and the internal microstructure of hydrogels were characterized by rheological test and scanning electron microscopy; the mechanical properties were characterized by compression test; the swelling rate and degradation rate were determined by mass method. The hydrogel was co-cultured with the cells, the cytotoxicity was measured by the lactate dehydrogenase method, the cell adhesion was measured by the float count method, and the cell growth and differentiation on the surface of the gel were observed by scanning electron microscope and fluorescence microscope.@*RESULTS@#The functional group substitution degrees of modified silk fibroin and hyaluronic acid were 17.99% and 48.03%, respectively. The prepared silk fibroin/hyaluronic acid composite hydrogel had a gel point of 40-60 s and had a porous structure inside the gel. The compressive strength was as high as 450 kPa and it would not break after ten cycles. The water absorption capacity of the composite hydrogel was 4-10 times of its own weight. Degradation experiments showed that the hydrogel was biodegradable, and the degradation rate reached 28%-42% after 35 d. The cell biology experiments showed that the cytotoxicity of the composite gel was low, the cell adhesion was good, and the growth and differentiation of the cells on the surface of the gel were good.@*CONCLUSIONS@#The photocurable silk fibroin/hyaluronic acid composite hydrogel can form a gel quickly, and has excellent mechanical properties, adjustable swelling rate and degradation degree, good biocompatibility, so it has promising application prospects in biomedicine.

The relationship between thiol-disulfide balance and idiopathic sudden sensorineural hearing loss / Relação entre equilíbrio tiol-dissulfeto e perda auditiva neurossensorial súbita idiopática

Abstract Introduction: Impaired cochlear perfusion is a major etiological factor in idiopathic sudden sensorineural hearing loss. Oxidative stress has been shown to be a risk factor for oxidative damage. Objectives: We investigated the role of oxidative stress in idiopathic sudden sensorineural hearing loss by comparing serum levels of oxidant and antioxidant molecules including thiol/disulfide homeostasis paraoxonase, stimulated thiol/disulfide homeostasis paraoxonase, arylesterase, ceruloplasmin and myeloperoxidase in patients who did and did not recover after treatment. Methods: The amount of dynamic disulfide was calculated by determining half of the difference between the total thiols and native thiols. After the determination of native, total thiol, and disulfide amounts, the disulfide/total thiol percent ratio, native thiol/total thiol ratio and disulfide/native thiol percent ratio were calculated and then compared between the two groups. Additionally, clinical relationship between audiological recovery and native thiol, disulfide, disulfide/native thiol percent ratio, and disulfide/total thiol percent ratio levels was investigated. Blood samples were also analyzed for the assessment of thiol/disulfide homeostasis paraoxonase, stimulated thiol/disulfide homeostasis paraoxonase, arylesterase, ceruloplasmin, and myeloperoxidase levels. Results: A significant difference was found between the two groups with regard to total oxidant status disulfide, disulfide/native thiol percent ratio, disulfide/total thiol percent ratio, and native thiol/total thiol ratio levels (p = 0.001, p = 0.001, p = 0.001, p = 0.003, p = 0.001, p = 0.002, respectively). However, no significant difference was found between the two groups with regard to thiol/disulfide homeostasis paraoxonase, stimulated thiol/disulfide homeostasis paraoxonase, ceruloplasmin, and myeloperoxidase levels (p > 0.05 for all). Conclusion: The results supported the common hypothesis that vascular pathologies are the primary cause of idiopathic sudden sensorineural hearing loss and that other etiological factors ultimately result in vascular pathologies. The oxidant-antioxidant and thiol-disulfide balances were impaired in the idiopathic sudden sensorineural hearing loss group.

Resumo Introdução: A perfusão coclear prejudicada é um fator etiológico importante na perda auditiva neurossensorial súbita idiopática (PANSSI). O estresse oxidativo mostrou ser um fator de risco para danos oxidativos. Objetivos: Investigamos o papel do estresse oxidativo na PANSSI mediante a comparação dos níveis séricos de moléculas oxidantes e antioxidantes, inclusive homeostase de tiol/dissulfeto, paraoxonase, paraoxonase estimulada, arilesterase, ceruloplasmina e mieloperoxidase em pacientes com e sem recuperação após o tratamento. Método: A quantidade de dissulfeto dinâmico foi calculada mediante a determinação de metade da diferença entre os tiois totais e os tiois nativos. Após a determinação das quantidades de tiol nativo, tiol total e dissulfeto, as razões percentuais de dissulfeto/tiol total, tiol nativo/tioltotal e dissulfeto/tiol nativo foram calculadas e depois comparadas entre os dois grupos. Além disso, a relação clínica entre a recuperação audiológica e os níveis de tiol nativo, tiol nativo/tiol total, dissulfeto, dissulfeto/tiol nativo e dissulfeto/tiol total foi investigada. Amostras de sangue também foram analisadas para avaliar os níveis de paraoxonase, paraoxonase estimulada, arilesterase, ceruloplasmina e mieloperoxidase. Resultados: Uma diferença significante foi encontrada entre os dois grupos em relação ao estado oxidante total e aos níveis de dissulfeto, dissulfeto/tiol nativo, dissulfeto/tiol total, tiol nativo/tiol total (p = 0,001, p = 0,001, p = 0,001, p = 0,003, p = 0,001, p = 0,002, respectivamente). Porém, não foi encontrada diferença significante entre os dois grupos em relação aos níveis de paraoxonase, paraoxonase estimulada, ceruloplasmina e mieloperoxidade (p> 0,05 para todos). Conclusão: Os resultados apoiaram a hipótese comum de que as doenças vasculares são a principal causa de PANSSI e que, em última análise, outros fatores etiológicos resultam em doenças vasculares. Os equilíbrios de oxidante-antioxidante e tiol-dissulfeto estavam prejudicados no grupo PANSSI.

Assessment of dynamic thiol-disulfide homeostasis in patients with lipoid proteinosis (Urbach-Wiethe syndrome)

SUMMARY OBJECTIVE: Lipoid proteinosis is a rare autosomal recessive genetic dermatological disease that occurs due to the accumulation of hyaline material in the skin and mucous membranes. This study aimed to investigate whether dynamic thiol-disulfide homeostasis is a new marker of oxidative stress in patients suffering from lipoid proteinosis. METHODS: The study group involved 17 patients with lipoid proteinosis and 17 healthy controls with same gender and age. Native thiol, total thiol, disulfide levels, and thiol-disulfide indexes were measured with the fully automated spectrophotometric method described by Erel and Neselioglu, and the results of the two groups were statistically analyzed. RESULTS: Serum total thiol and native thiol levels were significantly lower in lipoid proteinosis group compared to the control group (p=0.020 and p=0.014, respectively). The disulfide levels were found to be higher in lipoid proteinosis group, but there was no significant difference between two groups. CONCLUSIONS: Impaired dynamic thiol-disulfide homeostasis was observed in lipoid proteinosis patients, suggesting that thiol-disulfide homeostasis may have a role in the pathogenesis of this disease.

Proptosis is associated with thiol-disulfide in patients with Graves' ophthalmopathy

ABSTRACT Objective: Graves' ophthalmopathy (GO) is a vision-threatening finding observed in approximately half of Graves' disease patients. The pathophysiology of GO is unclear, and one of the suspected factors is oxidative stress. In our study, we compared the relationship between proptosis and SH-SS in patients diagnosed with GO. Materials and methods: In this prospective study, 40 recently diagnosed Graves' disease patients with proptosis, 40 recently diagnosed Graves' disease patients without GO and 30 healthy individuals with similar demographic characteristics were included. Serum thiol-disulfide (SH-SS) measurements were performed. Eye examinations were performed by a single ophthalmologist to check for the presence of GO, and proptosis values were recorded with a Hertel exophthalmometer. Results: Total SH values were lower in the group with proptosis than in the other groups (p < 0.05). Total and native SH values were lower in patients without proptosis than in the control group (p < 0.05). Total SH, native SH and SS levels were independently associated with proptosis (p < 0.05). According to this analysis, it was found that increasing SS and decreasing total and native SH levels increased the probability of proptosis by 24.4%, 32.7% and 32.4%, respectively. Conclusion: A decrease in SH, which is a natural antioxidant that protects the body against oxidative stress, and an increase in SS are important signs of oxidative damage. Proptosis and SH-SS are closely related in GO. This may help us detect GO and proptosis in Graves' patients. It can also assist in developing new options for preventing and treating GO.

Are thiol-disulfide homeostasis & neutrophil-to-lymphocyte ratio useful in the differential diagnosis of acute familial Mediterranean fever attacks & acute appendicitis?

Background & objectives: Continuous subclinical inflammation can be seen in patients with familial Mediterranean fever (FMF) during the attack-free period. The importance of oxidative stress parameters in acute appendicitis (AA) progression has also been shown in previous studies. So, oxidative stress and the oxidant/antioxidant balance may play a role in this persistent subclinical inflammation. With this background the main objective of this study was to investigate the usefulness of combining the thiol-disulfide homeostasis parameters and the neutrophil-to-lymphocyte ratio (NLR) in the differential diagnosis of AA and an acute FMF attack. Methods: The present study was conducted prospectively with 84 patients who were admitted to the emergency department between May 1, and December 31, 2018. Another 40 healthy individuals were assigned as the control group. The homeostasis parameters of thiol-disulfide were measured by a spectrophotometric method and NLR was measured in the patient and control groups. Results: Native thiol and total thiol values were lower, while disulfide values were insignificantly higher in patients with AA than in patients with FMF. The white blood cell (WBC), neutrophil and NLR values were significantly higher in the AA group (P<0.001, P<0.001, P<0.001, respectively). When the neutrophil cut-off value for AA was set at 8.55, the calculated sensitivity was 80 per cent, the specificity was 72.2 per cent, and the area under the curve was 0.837. Interpretation & conclusions: The results of this study suggest that neutrophil, WBC and NLR values can be useful in the differentiation of AA from an acute FMF attack.

Preparation of active thiol metabolite of clopidogrel by isolated rat liver perfusion / 中国药房

OBJECTIVE To estab lish the pre paration method of clopidogrel active thiol metabolite （CATM），and to provide reference for the synthesis of cis-CATM. METHODS CATM was prepared ，separated and purified with isolated rat liver perfusion and ChromCore 120 C18 preparative column ，using（S）-2-oxo-clopidogrel as substrate. The target compounds were identified by mass spectrometry and nuclear magnetic resonance spectroscopy. The retention time of the active configuration of CATM in the human body （cis-CATM）were compared to confirm the proportion of active configuration in the target product. RESULTS The conversion rate of the target product was 11.71％. The target products were identified as CATM by MS and 1H-NMR. Peak 2-peak 5 of CATM were four stereoisomers. The retention time of them were 21.3，22.3，26.5，27.3 min. The peak area ratios of them were 7.13％，7.23％，63.52％，14.97％，respectively. Based on that retention time of the active configuration of CATM in human body was 26.3 min，the active cis-stereoisomer in the target product CATM accounted for 63.52％. CONCLUSIONS This method is low-cost ，simple，and can prepare CATM with higher active configuration.

An evaluation of the relationship between vitamin D level and CTRP-9, tumor necrosis factor-alpha, thiol-disulfide hemostasis in women

SUMMARY OBJECTIVE: Many chronic diseases such as malignancy, cardiovascular diseases, endothelial dysfunction, and autoimmune diseases, which have been shown to be related to vitamin D in various studies; have similar relations with CTRP-9, TNFα, and thiol-disulfide hemostasis. We aimed to contribute to the literature by evaluating the relationship between CTRP-9, TNFα, and thiol-disulfide hemostasis and vitamin D levels, which we thought may have some effects on the pathogenesis of vitamin D deficiency. METHODS: In our study, 78 female volunteers older than 18 years were included. Volunteers were divided into three groups according to the reference values of vitamin D levels. Biochemical parameters, CTRP-9, TNFα, and thiol/disulfide hemostasis tests taken from all volunteers were studied. RESULTS: In this study, there was a significant difference in CTRP-9, TNFα, total thiol (TT), native thiol (NT), DIS (disulfide), TT/DIS, and NT/DIS levels in vitamin D groups (p<0.05). There was a significant negative correlation between vitamin D and TNFα and DIS, while a significant positive correlation was found with CTRP-9, TT, NT, TT/DIS, and NT/DIS (p<0.05). CONCLUSIONS: It was determined that vitamin D deficiency causes a significant decrease in CTRP-9 level and a significant increase in TNFα level, as well as an increase in thiol/disulfide hemostasis in favor of disulfide, which may be a risk factor for increased oxidative stress. We considered that these changes may play mediator roles for many chronic diseases and metabolic disorders that are increasing in frequency due to vitamin D deficiency.

Capsid destabilization and epitope alterations of human papillomavirus 18 in the presence of thimerosal / 药物分析学报

Thimerosal has been widely used as a preservative in drug and vaccine products for decades.Due to the strong propensity to modify thiols in proteins,conformational changes could occur due to covalent bond formation between ethylmercury(a degradant of thimerosal)and thiols.Such a conformational change could lead to partial or even complete loss of desirable protein function.This study aims to investigate the effects of thimerosal on the capsid stability and antigenicity of recombinant human papillomavirus(HPV)18 virus-like particles(VLPs).Dramatic destabilization of the recombinant viral capsid upon thimerosal treatment was observed.Such a negative effect on the thermal stability of VLPs preserved with thimerosal was shown to be dependent on the thimerosal concentration.Two highly neutralizing antibodies,13H12 and 3C3,were found to be the most sensitive to thimerosal treatment.The kinetics of antigenicity loss,when monitored with 13H12 or 3C3 as probes,yielded two distinctly different sets of kinetic parameters,while the data from both monoclonal antibodies(mAbs)followed a biphasic expo-nential decay model.The potential effect of thimerosal on protein function,particularly for thiol-containing proteinaceous active components,needs to be comprehensively characterized during formulation development when a preservative is necessary.

Effects of vitamin D administration on nociception and spinal cord pro-oxidant and antioxidant markers in a rat model of neuropathic pain

Reactive oxygen species (ROS) are involved in neuropathic pain, a complicated condition after nerve tissue lesion. Vitamin D appears to improve symptoms of pain and exhibits antioxidant properties. We investigated the effects of oral administration of vitamin D3, the active form of vitamin D, on nociception, the sciatic functional index (SFI), and spinal cord pro-oxidant and antioxidant markers in rats with chronic constriction injury (CCI) of the sciatic nerve, a model of neuropathic pain. Vitamin D3 (500 IU/kg per day) attenuated the CCI-induced decrease in mechanical withdrawal threshold and thermal withdrawal latency (indicators of antinociception) and SFI. The vitamin prevented increased lipid hydroperoxide levels in injured sciatic nerve without change to total antioxidant capacity (TAC). Vitamin D3 prevented increased lipid hydroperoxide, superoxide anion generation (SAG), and hydrogen peroxide (H2O2) levels in the spinal cord, which were found in rats without treatment at 7 and 28 days post-CCI. A significant negative correlation was found between mechanical threshold and SAG and between mechanical threshold and H2O2 at day 7. Vitamin D3 also prevented decreased spinal cord total thiols content. There was an increase in TAC in the spinal cord of vitamin-treated CCI rats, compared to CCI rats without treatment only at 28 days. No significant changes were found in body weight and blood parameters of hepatic and renal function. These findings demonstrated, for first time, that vitamin D modulated pro-oxidant and antioxidant markers in the spinal cord. Since antinociception occurred in parallel with oxidative changes in the spinal cord, the oxidative changes may have contributed to vitamin D-induced antinociception.

The effect of low dose ionizing radiation exposure on dynamic thiol-disulfide homeostasis and ischemia modified albumin levels: an observational study / Efeito da exposição à radiação ionizante de baixa dose na homeostase dinâmica de tiol-dissulfeto e níveis de albumina modificada por isquemia: estudo observacional

Abstract Background: The primary objective of this study was to investigate the effect of low dose ionizing radiation exposure on thiol/disulfide homeostasis and ischemia modified albumin levels. The secondary objective is to compare thiol/disulfide homeostasis and ischemia modified albumin levels among the personnel exposed to low dose ionizing radiation in anesthesia application areas, in and out of the operation room. Methods: The study included a total of 90 volunteers aged between 18 and 65 years old, with 45 personnel working in a setting with potential for radiation exposure (Exposed Group) and 45 personnel in a setting without radiation exposure (Control Group). Their native thiol, total thiol, disulphide, albumine and IMA levels were measured. Exposed group included personnel who were exposed to radiation outside the operating room - Operation room (−) Group and inside the operating room - Operation room (+) Group. Results: Albumin, native and total thiol levels were significantly lower in the participants exposed to radiation in the anesthesia application area; no statistically significant difference was found in terms of disulfide and ischemia modified albumin levels. In the Operation room (−) Group exposed to radiation, native thiol and total thiol values were significantly lower compared to the Operation room (+) Group. Conclusion: Awareness of being in danger of oxidative stress should be established in personnel exposed to radiation in the anesthesia application area following low dose ionizing radiation exposure, and the necessary measures should be taken.

Resumo Justificativa: O objetivo principal do estudo foi investigar o efeito de exposição à radiação ionizante de baixa dose nos níveis de homeostase tiol/dissulfeto e de albumina modificada por isquemia. O objetivo secundário foi comparar os níveis de homeostase tiol/dissulfeto e albumina modificada por isquemia entre indivíduos expostos à radiação ionizante de baixa dose nas áreas de procedimentos anestésicos, dentro e fora da sala de cirurgia. Método: O estudo incluiu um total de 90 voluntários com idades entre 18 e 65 anos, 45 profissionais que trabalhavam em ambiente de exposição potencial a radiação (Grupo Exposto) e 45 profissionais que trabalhavam em ambiente sem exposição à radiação (Grupo Controle). Foram medidos os níveis de tiol nativo, tiol total, dissulfeto, albumina e albumina modificada por isquemia. O Grupo Exposto era constituído por profissionais expostos a radiação fora da sala de cirurgia - Grupo sala de cirurgia (-) e na sala de cirurgia - Grupo sala de cirurgia (+). Resultados: Os níveis de albumina, tiol nativo e total foram significantemente mais baixos nos participantes expostos à radiação em área de realização de anestesia, e nenhuma diferença estatisticamente significante foi encontrada para os níveis de dissulfeto e albumina modificada por isquemia. No Grupo exposto sala de cirurgia (-), os valores de tiol nativo e tiol total foram significantemente mais baixos quando comparados ao Grupo sala de cirurgia (+). Conclusões: Os profissionais expostos à radiação em área de realização de anestesia devem ser conscientizados quanto ao perigo do estresse oxidativo após exposição à radiação ionizante de baixa dose e medidas cabíveis devem ser instituídas.

Aging and low-intensity exercise change oxidative biomarkers in brain regions and radiographic measures of femur of Wistar rats

We investigated changes in oxidative biomarkers in brain regions such as brainstem, cerebellum, and cerebral cortex of 3-, 6-, 18-, 24-, and 30-month-old rats. We also assessed the effects of low-intensity exercise on these biomarkers in these regions of 6-, 18-, and 24-month-old rats that started exercise on a treadmill at 3, 15, and 21 months of age, respectively. Radiographic images of the femur were taken for all rats. A total of 25 rats (age: twelve 6-, ten 18-, ten 24-, and three 30-month-old rats) were used. Lipid hydroperoxide levels increased in cerebellum at 18 months. Total antioxidant activity exhibited lowest values in brainstem at 3 months. Superoxide dismutase activity did not exhibit significant changes during aging. Total thiol content exhibited lowest values in brain regions of 24- and 30-month-old rats. Exercise reduced total thiol content in brainstem at 6 months, but no change occurred in other regions and other ages. Femur increased its length and width and cortical thickness with advancing age. No change occurred in medullary width. Radiolucency increased and sclerosis was found in cortical and medullary bone with advancing age. Exercise reduced radiolucency and medullary sclerosis. Therefore, aging differentially changed oxidative biomarkers in different brain regions and radiographic measures of the femur. Low-intensity exercise only ameliorated some radiographic measurements of femur. Since the present study possessed limitations (small number of rats per group), a beneficial effect of regular low-intensity exercise on oxidative markers in brain cannot be ruled out.

Thiol-disulfide homeostasis in breast cancer patients

Objective: The aim of our study is to assess thiol-disulfide homeostasis (TDH), which is a biomarker of systemic oxidative stress, in breast cancer patients. Materials and Methods: Thirty-seven breast cancer patients and 31 age-matched healthy volunteers were enrolled in this study. Serum native thiol, disulfide, and total thiol levels and disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol ratios were analyzed using a novel colorimetric method. Results: Serum native thiol level was statistically significantly lower in breast cancer patients (350.39 ± 7.15) than in healthy controls (380.60 ± 7.35) (P = 0.008). Serum disulfide level was statistically significantly higher in breast cancer patients (24.96 ± 0.85) than in healthy controls (19.25 ± 1.34) (P = 0.002). Conclusion: To our knowledge, this study is the first study in the literature that investigated TDH in breast cancer patients. We have concluded that an alteration in TDH due to oxidative stress is likely to have a role in the pathogenesis of breast cancer

High-intensity exercise-induced oxidative stress in sedentary pre-pubertal & post-pubertal boys: A comparative study

Background & objectives: High-intensity exercise results in oxidative stress in adult population. Impact of pubertal attainment on high-intensity exercise-induced oxidative stress in sedentary paediatric population has not been investigated in detail. The present study was conducted to investigate the extent of high-intensity exercise-induced oxidative stress in sedentary pre- and post-pubertal boys through estimation of serum thiobarbituric acid reactive substances (TBARS), total thiol content and activities of superoxide dismutase (SOD) and catalase (CAT). Methods: Sixty four sedentary pre-pubertal (n=32, age = 10.21�67 yr) and post-pubertal (n=32, age = 15.58�47 yr) boys performed incremental treadmill running exercise at 80 per cent of the age predicted maximum heart rate till volitional exhaustion. Blood sample (5 ml) was drawn from each individual before and after the exercise for estimation of oxidative stress markers. Results: Pre-exercise SOD activity and total thiol level showed significant positive relationship with age and were significantly higher in post-pubertal boys. Serum TBARS level, SOD and CAT activities increased while total thiol content decreased in both the groups following exercise. Post-exercise percentage change in TBARS, SOD activity and total thiol level was significantly higher in post-pubertal boys, and these variables had significant positive relationship with age. No significant intergroup variations were noted in CAT activity before or after exercise. Interpretation & conclusions: Extent of post-exercise oxidative stress increased significantly with attainment of puberty. However, baseline and post-exercise antioxidation status also increased significantly as a function of age with pubertal maturation allowing the post-pubertal boys to counter relatively higher oxidative stress more efficiently than their pre-pubertal counterparts. Post-exercise upregulation in CAT activity might not be influenced by age or pubertal maturation in this age group.

La homeostasis de tiol/disulfuro es un indicador del estrés oxidativo en los niños críticamente enfermos con sepsis / Thiol-disulphide homeostasis is an oxidative stress indicator in critically ill children with sepsis

Objetivo. Evaluar un novedoso marcador del estrés oxidativo (la homeostasis de tiol /disulfuro) en la sepsis pediátrica y determinar sus efectos sobre el pronóstico de esta afección. Métodos. En el estudio, se incluyeron pacientes con diagnóstico de sepsis y controles sanos. Se midieron las concentraciones de tiol total, tiol nativo, disulfuro, disulfuro /tiol total, disulfuro /tiol nativo y tiol nativo/tiol total en los grupos con sepsis y de referencia. Se compararon los parámetros entre los supervivientes y los no supervivientes del grupo con sepsis. Se midieron las concentraciones de hemoglobina, leucocitos, trombocitos, lactato y proteína C-reactiva en los pacientes con sepsis al momento del diagnóstico. Se utilizaron el puntaje de riesgo de mortalidad pediátrico (Pediatric Risk of Mortality, PRISM) y el puntaje de disfunción orgánica (Pediatric Logistic Organ Dysfunction, PELOD) para estimar la gravedad de la enfermedad. Resultados. En el grupo con sepsis se incluyó a 38 pacientes y en el de referencia, a 40 niños sanos. Las concentraciones plasmáticas de tiol en los pacientes con sepsis fueron significativamente inferiores que las del grupo de referencia (p < 0,001). Conclusión. La homeostasis de tiol/disulfuro fue anormal en los niños con sepsis en la unidad de cuidados intensivos pediátricos.

The aim of this study is to evaluate a novel oxidative stress marker (thiol-disulphide homeostasis) in paediatric sepsis and to determine their effects on the prognosis of sepsis. Patients diagnosed with sepsis (n= 38) and healthy controls (n= 40) were incorporated in the study. Total thiol, native thiol, disulphide, disulphide/total thiol, disulphide/native thiol, and native thiol /total thiol levels were measured in the sepsis and control groups. Additionally, the parameters were compared between survivors and non-survivors in the sepsis group. The levels of hemoglobin, white blood cell, platelet, lactate, and C-reactive protein were measured in patients with sepsis at diagnosis. The paediatric risk of mortality and paediatric logistic organ dysfunction scores of the patients were used to estimate the disease severity. The plasma thiol levels of the patients with sepsis were significantly lower than the control group (p < 0.001). This study showed that thiol/disulphide homeostasis is abnormal in children with sepsis in Paediatric Intensive Care Unit.

Research advances in hydrogen sulfide donors / 中国药科大学学报

@#Hydrogen sulfide(H2S)is an endogenous gas messenger molecule with extremely broad biological activities including vasodilation, anti-oxidation, anti-inflammation, cardioprotection and anti-tumor. Similar to other gas messenger molecules, the biological activity of H2S is dependent on its location, concentration and duration of exposure. Therefore, the key scientific issue is how to improve the selectivity of H2S donor molecules to release appropriate concentrations of H2S at the target site(commonly pathological place), exerting therapeutic efficacy with limited side-effects. This article reviews the structures and H2S release mechanisms of two classes of H2S donors focusing on the advances in the recently developed H2S donors with controllable release potential of H2S, thus providing new ideas for future H2S-based drug research.

Age-related changes and effects of regular low-intensity exercise on gait, balance, and oxidative biomarkers in the spinal cord of Wistar rats

The present study aimed to analyze age-related changes to motor coordination, balance, spinal cord oxidative biomarkers in 3-, 6-, 18-, 24-, and 30-month-old rats. The effects of low-intensity exercise on these parameters were also analyzed in 6-, 18-, and 24-month-old rats. Body weight, blood glucose, total cholesterol, and high-density lipoprotein (HDL) cholesterol were assessed for all rats. The soleus muscle weight/body weight ratio was used to estimate skeletal muscle mass loss. Body weight increased until 24 months; only 30-month-old rats exhibited decreased blood glucose and increased total cholesterol and HDL cholesterol. The soleus muscle weight/body weight ratio increased until 18 months, followed by a small decrease in old rats. Exercise did not change any of these parameters. Stride length and step length increased from adult to middle age, but decreased at old age. Stride width increased while the sciatic functional index decreased in old rats. Performance in the balance beam test declined with age. While gait did not change, balance improved after exercise. Aging increased superoxide anion generation, hydrogen peroxide levels, total antioxidant capacity, and superoxide dismutase activity while total thiol decreased and lipid hydroperoxides did not change. Exercise did not significantly change this scenario. Thus, aging increased oxidative stress in the spinal cord, which may be associated with age-induced changes in gait and balance. Regular low-intensity exercise is a good alternative for improving age-induced changes in balance, while beneficial effects on gait and spinal cord oxidative biomarkers cannot be ruled out because of the small number of rats investigated (n=5 or 6/group).

Treatment with ascorbic acid and alpha-tocopherol modulates oxidative-stress markers in the spinal cord of rats with neuropathic pain

Vitamin E (vit. E) and vitamin C (vit. C) are antioxidants that inhibit nociception. The effect of these vitamins on oxidative-stress markers in the spinal cord of rats with chronic constriction injury (CCI) of the sciatic nerve is unknown. This study investigated the effect of intraperitoneal administration of vit. E (15 mg·kg-1·day-1) and vit. C (30 mg·kg-1·day-1), given alone or in combination, on spinal cord oxidative-stress markers in CCI rats. Adult male Wistar rats weighing 200-250 g were divided equally into the following groups: Naive (rats did not undergo surgical manipulation); Sham (rats in which all surgical procedures involved in CCI were used except the ligature), and CCI (rats in which four ligatures were tied loosely around the right common sciatic nerve), which received injections of vitamins or vehicle (saline containing 1% Tween 80) for 3 or 10 days (n=6/each group). The vitamins prevented the reduction in total thiol content and the increase in superoxide-anion generation that were found in vehicle-treated CCI rats. While nitric-oxide metabolites increased in vehicle-treated CCI rats 3 days after surgery, these metabolites did not show significant changes in vitamin-treated CCI rats. In all rats, total antioxidant capacity and hydrogen-peroxide levels did not change significantly. Lipid hydroperoxides increased 25% only in vehicle-treated CCI rats. These changes may contribute to vit. C- and vit. E-induced antinociception, because scavenging reactive oxygen species seems to help normalize the spinal cord oxidative status altered by pain.

Efeito pró-oxidante do hidroperóxido de urato sobre proteínas sensíveis às alterações redox: implicações na resposta inflamatória / Pro-oxidant effect of urate hydroperoxide on redoxsensitive proteins: implications on inflammatory reponse

O hidroperóxido de urato (HOOU) é o produto da oxidação do ácido úrico por peroxidases. Sua produção é favorecida durante a inflamação e hiperuricemia, uma vez que há grande quantidade de ácido úrico, peroxidases inflamatórias e superóxido. Neste sentido, o objetivo deste estudo foi avaliar o efeito do hidroperóxido de urato sobre proteínas sensíveis à modulação redox em um ambiente inflamatório asséptico e outro que imita infecção. Assim, nesta tese comparou-se a estrutura química do HOOU obtido fotoquimicamente daquele obtido através da catálise enzimática pela mieloperoxidase. A obtenção do HOOU por foto-oxidação permitiu o melhor isolamento do composto. Este oxidante foi capaz de reagir especificamente com os aminoácidos contendo enxofre (metionina e cisteína). Neste sentido, foi investigada sua reatividade com tiol-peroxidases detoxificadoras de peróxido, a peroxiredoxina 1 e 2 (Prx1 e Prx2). O HOOU apresentou cinética rápida de reação com a Prx1, k = 4,9 × 105 M-1s-1 e Prx2, k = 2,3 × 106 M-1s-1, o que as torna um provável alvo celular, além disso, foi capaz de oxidar a Prx2 de eritrócitos humanos, mostrando ser capaz de atravessar a membrana plasmática. Além das Prxs, a albumina do soro também desempenha papel importante na homeostase redox. O HOOU foi capaz de oxidar a albumina com constante de velocidade de 0,2 × 102 M-1s- 1. Outra tiol-proteína com importante função na homeostase e sinalização redox é a tioredoxina (Trx). A Trx foi oxidada pelo HOOU com constante de reação de 2,8 × 102 M-1s-1 e foi liberada juntamente com a Prx1 e Prx2 das células de macrófagos humanos (linhagem THP-1) quando estas células foram incubadas com HOOU. A liberação dessas proteínas é reconhecidamente um sinal de estresse celular. Assim o HOOU pode estar envolvido na exacerbação do estresse oxidativo em ambiente inflamatório. Quando neutrófilos (linhagem HL- 60) e macrófagos humanos (linhagem THP-1) foram incubados na presença de ácido úrico e Pseudomonas aeruginosa houve uma diminuição na produção de ácido hipocloroso (HOCl). Isto se deveu à competição entre ácido úrico e cloreto pela mieloperoxidase e resultou em menor atividade microbicida pelas células, demonstrando que a formação do HOOU não contribui e, ao contrário, prejudica a atividade microbicida das células inflamatórias. Dessa forma, a oxidação do ácido úrico e formação do hidroperóxido de urato tanto altera a atividade microbicida das células inflamtárias, quanto leva à oxidação de tiósproteínas importantes para manutenção da homeostase redox. Assim, o HOOU pode ser o responsável pelos efeitos pró-oxidantes e pró-inflamatórios do ácido úrico solúvel, e isso indica que o papel antioxidante do ácido úrico deve ser revisto em situações de inflamação.

Urate hydroperoxide (HOOU) is the product of the oxidation of uric acid by peroxidases. The formation of HOOU is favored during inflammation and in hyperuricemia, where there is plenty amount of uric acid, inflammatory peroxidases and superoxide. Therefore, the aim of the present study was to evaluate the effect of urate hydroperoxide on redox sensitive proteins in an inflammatory environment and another that mimics infection. In this thesis the chemical structure of the HOOU produced by photo-oxidation was compared to that obtained by myeloperoxidase catalysis. The chemical production of HOOU allowed a better purification of the compound. This oxidant was able to specifically react with sulfur containing amino acids (methionine and cysteine). In this sense, its reactivity with peroxiredoxins (Prx1 and Prx2) was investigated. HOOU reacted fast with Prx1 k = 4.9 × 105 M-1s-1 and Prx2 k = 2.3 × 106 M-1s-1. In addition, HOOU was able to oxidize Prx2 from intact erythrocytes at the same extend as does hydrogen peroxide. Albumin is an important thiol-containing protein to redox homeostasis in plasma. HOOU was able to oxidize albumin with a rate constant of 0.2 × 102 M-1s-1. Another protein with important function in redox homeostasis is thioredoxin (Trx). Trx was oxidized by HOOU with a rate constant of 2.8 × 102 M-1s-1 and was released together with Prx1 and Prx2 from human macrophages cells (THP-1 cell line) that were incubated with HOOU. The release of these proteins is a signal of cellular stress. Thus, HOOU may be involved in the exacerbation of oxidative stress in inflammatory environments. When neutrophil (HL-60 cell line) and macrophages (THP-1 cell line) were incubated with uric acid and Pseudomonas aeruginosa there was a decrease in hypochlorous acid (HOCl) production because of the competition between chloride and uric acid by myeloperoxidase. It decreased HOCl and impaired the microbicidal activity of the cells, showing that HOOU does not contribute in bacteria clearance. Therefore, the oxidation of uric acid to urate hydroperoxide impairs microbicidal activity and oxidizes thiol-proteins in inflammatory cells contributing to a pro-oxidant status. In this context, the antioxidant role of uric acid in inflammatory response should be reviwed.

Can the Thiol/Disulfide Imbalance Be a Predictor of Colchicine Resistance in Familial Mediterranean Fever?

Familial Mediterranean fever (FMF) is a chronic autoinflammatory condition characterized by fever attacks and recurrent polyserositis. Subclinical inflammation that persists during attack-free periods can result in oxidative stress (OS) damage. Thiol groups bind to reactive oxygen radicals and protect cells and tissues from OS damage. The aim of this study was to investigate the relationship between thiol-disulfide balance and colchicine resistance in FMF patients during an attack or attack-free period. A newly developed spectrophotometric method was used to measure native thiol (NT) and disulfide (DS) levels in FMF patients and an age-sex matched group of healthy controls. NT and DS levels were compared in FMF patients 1) with vs. without colchicine resistance; and 2) during an attack (FMF-AP) vs. attack-free period (FMF-AFP). A total of 118 FMF patients and 60 healthy controls were studied. NT (P < 0.001) and total thiol (TT) (P < 0.001) levels in FMF patients were significantly lower compared to healthy controls. NT (P = 0.030) and TT (P = 0.010) levels of FMF-AP patients were significantly lower than that of FMF-AFP patients. FMF-AP patients had significantly higher DS levels than FMF-AFP patients (P = 0.039). Compared to FMF patients without colchicine resistance, elevated levels of DS (P = 0.019) but not NT (P = 0.620) and TT (P = 0.718) were found in those with colchicine resistance. Thiol-disulfide homeostasis is altered in FMF patients during an attack period and this imbalance may be associated with colchicine resistance.