Coordinated upregulation of a series of endogenous antioxidants and phase 2 enzymes as a novel strategy for protecting renal tubular cells from oxidative and electrophilic stress

3H-1,2-Dithiole-3-Thione as a Potentially Novel Therapeutic Compound for Sepsis Intervention

Through the history of modern medicine, bioactive components in natural products have been either employed directly as medicines or used as prototypes for synthetic drug development. This brief Research Highlights paper considers 3H-1,2-dithiole-3-thione (D3T), a member of the 1,2-dithiole-3-thiones-compounds which may naturally occur in cruciferous vegetables. Among 1,2-dithiole-3-thiones, D3T is the most potent member with regard to the capacity of inducing tissue defenses against oxidative and inflammatory stress. Oxidative and inflammatory stress is a major pathophysiological process involved in numerous human disorders, including cancer, cardiovascular diseases, neurodegeneration, and sepsis, to name just a few. This article surveys recent major research findings on D3T as an inducer of tissue antioxidative and antiinflammatory defenses and as a potential therapeutic modality for sepsis intervention.

3H-1,2-dithiole-3-thione as a novel therapeutic agent for the treatment of experimental autoimmune encephalomyelitis

3H-1,2-dithiole-3-thione (D3T), the simplest member of the sulfur-containing dithiolethiones, is found in cruciferous vegetables, and has been previously reported to be a potent inducer of antioxidant genes and glutathione biosynthesis by activation of the transcription factor Nrf2. D3T is a cancer chemopreventive agent and possesses anti-inflammatory properties. Although D3T has been shown to protect against neoplasia, the effect of D3T in the autoimmune inflammatory disease multiple sclerosis/experimental autoimmune encephalomyelitis (EAE) is unknown. The present study is the first report of the therapeutic effect of D3T in EAE. Our results show D3T, administered post immunization, not only delays disease onset but also dramatically reduces disease severity in EAE. Strikingly, D3T, administered post disease onset of EAE, effectively prevents disease progression and exacerbation. Mechanistic studies revealed that D3T suppresses dendritic cell activation and cytokine production, inhibits pathogenic Th1 and Th17 differentiation, represses microglia activation and inflammatory cytokine expression, and promotes microglia phase II enzyme induction. In summary, these results indicate that D3T affects both innate and adaptive immune cells, and the protective effect of D3T in EAE might be attributed to its effects on modulating dendritic cell and microglia activation and pathogenic Th1/Th17 cell differentiation.

Urinary π-glutathione S-transferase Predicts Advanced Acute Kidney Injury Following Cardiovascular Surgery

Urinary biomarkers augment the diagnosis of acute kidney injury (AKI), with AKI after cardiovascular surgeries being a prototype of prognosis scenario. Glutathione S-transferases (GST) were evaluated as biomarkers of AKI. Urine samples were collected in 141 cardiovascular surgical patients and analyzed for urinary alpha-(α-) and pi-(π-) GSTs. The outcomes of advanced AKI (KDIGO stage 2, 3) and all-cause in-patient mortality, as composite outcome, were recorded. Areas under the receiver operator characteristic (ROC) curves and multivariate generalized additive model (GAM) were applied to predict outcomes. Thirty-eight (26.9%) patients had AKI, while 12 (8.5%) were with advanced AKI. Urinary π-GST differentiated patients with/without advanced AKI or composite outcome after surgery (p < 0.05 by generalized estimating equation). Urinary π-GST predicted advanced AKI at 3 hrs post-surgery (p = 0.033) and composite outcome (p = 0.009), while the corresponding ROC curve had AUC of 0.784 and 0.783. Using GAM, the cutoff value of 14.7 μg/L for π-GST showed the best performance to predict composite outcome. The addition of π-GST to the SOFA score improved risk stratification (total net reclassification index = 0.47). Thus, urinary π-GST levels predict advanced AKI or hospital mortality after cardiovascular surgery and improve in SOFA outcome assessment specific to AKI.

Influence of endothelial dysfunction on telomere length in subjects with metabolic syndrome: LIPGENE study

Previous evidences support that increased oxidative stress (OxS) may play an important role in metabolic syndrome (MetS) and both are closely linked to vascular dysfunction. This study determined whether there is a relationship between endothelial function and relative telomere length (RTL) in MetS subjects. In this cross-sectional study from the LIPGENE cohort, a total of 88 subjects (36 men and 52 women) were divided into four groups by quartiles of telomere length. We measured ischemic reactive hyperemia (IRH), total nitrite (NO) and protein carbonyl (PC) plasma levels, F2-isoprostanes urinary levels, and superoxide dismutase (SOD) and glutathione peroxidase (GPx) plasma activities. IRH and NO plasma levels were higher in subjects with longer RTL (quartiles 3 and 4), while PC plasma levels, F2-isoprostanes urinary levels, and GPx and SOD plasma activities were lower in quartile 4 subjects (longest RTL). Additionally, MetS subjects with longer RTL had greater homeostatic model assessment-β level and lower triglycerides plasma levels. Our results suggest that endothelial dysfunction, associated with high levels of OxS, could be entailed in an increment of telomere attrition. Thus, further support of the molecular and cellular mechanisms involved in vascular dysfunction may contribute to the development of strategies to decelerate vascular aging or prevent cardiovascular disease.

Redox-dependent anti-inflammatory signaling actions of unsaturated fatty acids

Unsaturated fatty acids are metabolized to reactive products that can act as pro- or anti-inflammatory signaling mediators. Electrophilic fatty acid species, including nitro- and oxo-containing fatty acids, display salutary anti-inflammatory and metabolic actions. Electrophilicity can be conferred by both enzymatic and oxidative reactions, via the homolytic addition of nitrogen dioxide to a double bond or via the formation of α,β-unsaturated carbonyl and epoxide substituents. The endogenous formation of electrophilic fatty acids is significant and influenced by diet, metabolic, and inflammatory reactions. Transcriptional regulatory proteins and enzymes can sense the redox status of the surrounding environment upon electrophilic fatty acid adduction of functionally significant, nucleophilic cysteines. Through this covalent and often reversible posttranslational modification, gene expression and metabolic responses are induced. At low concentrations, the pleiotropic signaling actions that are regulated by these protein targets suggest that some classes of electrophilic lipids may be useful for treating metabolic and inflammatory diseases.

Urinary glutathione S-transferases in the pathogenesis and diagnostic evaluation of acute kidney injury following cardiac surgery: a critical review

PURPOSE OF REVIEW

A focused review of the nature, source, physiological role and rapidly expanding evidence for glutathione S-transferase (GST) subtypes π and α as biomarkers of acute kidney injury (AKI) in patients undergoing cardiac surgery. Expanded insights into the site-specific expression of the GSTs in defined parts of the nephron during renal damage are presented, with particular emphasis on the pathogenesis of cardiac surgery and cardiopulmonary bypass (CPB)-associated AKI and the role of GSTs in oxygen radical disposal.

RECENT FINDINGS

Recent developments have highlighted a potential role of urinary α-GST and π-GST in the diagnostic evaluation of cardiac surgery-associated AKI. Both urinary α-GST and π-GST are detected in the postoperative period. π-GST performed best at predicting AKI severity at the time of the initial diagnosis of AKI. α-GST was able to predict the future development of both stage 1 and stage 3 AKI.

SUMMARY

The current data from a small number of patients suggest a potential role of urinary GSTs in the clinical diagnostic evaluation of AKI following cardiac surgery. The performance of the GSTs for the early diagnosis of AKI needs to be validated in larger multicentre studies and in other patient populations at increased risk of AKI (e.g. patients with acute transplant rejection, septic patients). Comparison with other emerging AKI biomarkers is required to continue the development of π-GST and α-GST. Finally, additional studies examining the pathophysiological role of the GSTs in minimizing oxygen free radical exposure in the renal tubules during CPB may shed further light into their role as promising biomarkers of cardiac surgery-associated AKI.

Oxidative stress is associated with the number of components of metabolic syndrome: LIPGENE study

Previous evidence supports the important role that oxidative stress (OxS) plays in metabolic syndrome (MetS)-related manifestations. We determined the relationship between the number of MetS components and the degree of OxS in MetS patients. In this comparative cross-sectional study from the LIPGENE cohort, a total of 91 MetS patients (43 men and 48 women; aged between 45 and 68 years) were divided into four groups based on the number of MetS components: subjects with 2, 3, 4 and 5 MetS components (n=20, 31, 28 and 12, respectively). We measured ischemic reactive hyperemia (IRH), plasma levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), total nitrite, lipid peroxidation products (LPO), hydrogen peroxide (H₂O₂), superoxide dismutase (SOD) and glutathione peroxidase (GPx) plasma activities. sVCAM-1, H₂O₂ and LPO levels were lower in subjects with 2 or 3 MetS components than subjects with 4 or 5 MetS components. IRH and total nitrite levels were higher in subjects with 2 or 3 MetS components than subjects with 4 or 5 MetS components. SOD and GPx activities were lower in subjects with 2 MetS components than subjects with 4 or 5 MetS components. Waist circumference, weight, age, homeostatic model assessment-β, triglycerides (TGs), high-density lipoprotein and sVCAM-1 levels were significantly correlated with SOD activity. MetS subjects with more MetS components may have a higher OxS level. Furthermore, association between SOD activity and MetS components may indicate that this variable could be the most relevant OxS biomarker in patients suffering from MetS and could be used as a predictive tool to determine the degree of the underlying OxS in MetS.

Correlation of histopathology, urinary biomarkers, and gene expression responses following hexachloro-1:3-butadiene-induced acute nephrotoxicity in male Hanover Wistar rats: a 28-day time course study

Hexachloro-1:3-butadiene (HCBD) causes segment-specific injury to the proximal renal tubule. A time course study of traditional and more recently proposed urinary biomarkers was performed in male Hanover Wistar rats receiving a single intraperitoneal (ip) injection of 45 mg/kg HCBD. Animals were killed on days 1, 2, 3, 4, 5, 6, 7, 10, 14, and 28 postdosing and the temporal response of renal biomarkers was characterized using kidney histopathology, urinary and serum biochemistry, and gene expression. Histopathologic evidence of tubular degeneration was seen from day 1 until day 3 postdosing and correlated with increased urinary levels of α-glutathione S-transferase (α-GST), albumin, glucose, and kidney injury molecule-1 (KIM-1), and increased gene expression of KIM-1, NAD(P)H dehydrogenase, quinone 1, and heme oxygenase (decycling) 1. Histopathologic evidence of tubular regeneration was seen from day 2 postdosing and correlated with raised levels of urinary KIM-1 and osteopontin and increased gene expression of KIM-1 and annexin A7. Traditional renal biomarkers generally demonstrated low sensitivity. It is concluded that in rat proximal tubular injury, measurement of a range of renal biomarkers, in conjunction with gene expression analysis, provides an understanding of the extent of degenerative changes induced in the kidney and the process of regeneration.

Effects of acupuncture at Taixi acupoint (KI3) on kidney proteome

This research explored and identified the protein composition of rat kidneys after acupuncture at the Taixi acupoint (KI3). Twelve adult male Wistar rats were randomly divided into a control group (n = 6) and an acupuncture group (n = 6). Rats in the acupuncture group received electroacupuncture on the bilateral KI3 for seven days. The kidneys were perfused with ice-cold saline and all kidney proteins were isolated. After protein sample preparation, two-dimensional gel electrophoresis (2-DE) was performed. The interesting spots were analyzed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). There were nine protein spots with three-fold up-regulation in the kidney after the acupuncture. NAD-dependent isocitrate dehydrogenase and quinone reductase, the proteins involved in energy metabolism, the reduction of endogenous quinones, chemoprotection, and electrophilic stress, were identified. The data indicated that acupuncture at the KI3 of the kidney meridian of the foot shaoyin was able to increase NAD-dependent isocitrate dehydrogenase and quinone reductase expression in the kidney, and supported the relationship between the kidney and KI3.

Postprandial antioxidant effect of the Mediterranean diet supplemented with coenzyme Q10 in elderly men and women

Postprandial oxidative stress is characterized by an increased susceptibility of the organism towards oxidative damage after consumption of a meal rich in lipids and/or carbohydrates. We have investigated whether the quality of dietary fat alters postprandial cellular oxidative stress and whether the supplementation with coenzyme Q(10) (CoQ) lowers postprandial oxidative stress in an elderly population. In this randomized crossover study, 20 participants were assigned to receive three isocaloric diets for periods of 4 week each: (1) Mediterranean diet supplemented with CoQ (Med+CoQ diet), (2) Mediterranean diet (Med diet), and (3) saturated fatty acid-rich diet (SFA diet). After a 12-h fast, the volunteers consumed a breakfast with a fat composition similar to that consumed in each of the diets. CoQ, lipid peroxides (LPO), oxidized low-density lipoprotein (oxLDL), protein carbonyl (PC), total nitrite, nitrotyrosine plasma levels, catalase, superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities and ischemic reactive hyperaemia (IRH) were determined. Med diet produced a lower postprandial GPx activity and a lower decrease in total nitrite level compared to the SFA diet. Med and Med+CoQ diets induced a higher postprandial increase in IRH and a lower postprandial LPO, oxLDL, and nitrotyrosine plasma levels than the SFA diet. Moreover, the Med+CoQ diet produced a lower postprandial decrease in total nitrite and a greater decrease in PC levels compared to the other two diets and lower SOD, CAT, and GPx activities than the SFA diet.In conclusion, Med diet reduces postprandial oxidative stress by reducing processes of cellular oxidation and increases the action of the antioxidant system in elderly persons and the administration of CoQ further improves this redox balance.