Efficacy of Marigold Extract-Loaded Formulations Against UV-induced Oxidative Stress

The present study investigated the potential use of topical formulations containing marigold extract (ME) (Calendula officinalis extract) against ultraviolet (UV) B irradiation-induced skin damage. The physical and functional stabilities, as well as the skin penetration capacity, of the different topical formulations developed were evaluated. In addition, the in vivo capacity to prevent/treat the UVB irradiation-induced skin damage, in hairless mice, of the formulation with better skin penetration capacity was investigated. All of the formulations were physically and functionally stable. The gel formulation [Formulation 3 (F3)] was the most effective for the topical delivery of ME, which was detected as 0.21 mu g/cm(2) of narcissin and as 0.07 mu g/cm(2) of the rutin in the viable epidermis. This formulation was able to maintain glutathione reduced levels close to those of nonirradiated animals, but did not affect the gelatinase-9 and myeloperoxidase activities increased by exposure to UVB irradiation. In addition, F3 reduced the histological skin changes induced by UVB irradiation that appear as modifications of collagen fibrils. Therefore, the photoprotective effect in hairless mice achieved with the topical application of ME in gel formulation is most likely associated with a possible improvement in the collagen synthesis in the subepidermal connective tissue. (C) 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:2182-2193, 2011

Diabetes and Vascular Disease: Basic Concepts of Nitric Oxide Physiology, Endothelial Dysfunction, Oxidative Stress and Therapeutic Possibilities

The vascular manifestations associated with diabetes mellitus (DM) result from the dysfunction of several vascular physiology components mainly involving the endothelium, vascular smooth muscle and platelets. It is also known that hyperglycemia-induced oxidative stress plays a role in the development of this dysfunction. This review considers the basic physiology of the endothelium, especially related to the synthesis and function of nitric oxide. We also discuss the pathophysiology of vascular disease associated with DM. This includes the role of hyperglycemia in the induction of oxidative stress and the role of advanced glycation end-products. We also consider therapeutic strategies.

Antioxidant status and biomarkers of oxidative stress in bovine leukemia virus-infected dairy cows

Bovine leukemia virus (BLV) is among the most widespread livestock pathogens in many countries. Despite advances in understanding the pathogenesis of this disease, little is known about the involvement of oxidative stress. Therefore, this study examined the antioxidant status and the markers of oxidative stress in BLV-infected dairy cows. BLV infection was associated with an increase in triacylglycerol levels, a decrease in glutathione peroxidase (GSH-Px) activity and a tendency toward lower superoxide dismutase activity in the infected animals. No significant difference was observed in other markers of oxidative stress (i.e., conjugated dienes, hydroperoxides and malondialdehyde) in the infected animals compared to controls. A novel method for the analysis of oxidative stress, Z-scan based on the measurement of the mean-value of 9 in low density lipoprotein indicated that the infected animals had low-density lipoprotein particles that were slightly less modified than those from the healthy group. Thus, we conclude that BLV infection is associated with a selective decrease in GSH-Px activity without any alteration in the common plasma markers of oxidative stress. (C) 2011 Elsevier B.V. All rights reserved.

Bcl-X-L translocation in renal tubular epithelial cells in vitro protects distal cells from oxidative stress

Background. The molecular pathogenesis of different sensitivities of the renal proximal and distal tubular cell populations to ischemic injury, including ischemia-reperfusion (IR)-induced oxidative stress, is not well-defined. An in vitro model of oxidative stress was used to compare the survival of distal [Madin-Darby canine kidney (MDCK)] and proximal [human kidney-2 (HK-2)] renal tubular epithelial cells, and to analyze for links between induced cell death and expression and localization of selected members of the Bcl-2 gene family (anti-apoptotic Bcl-2 and Bcl-X-L, pro-apoptotic Bax and Bad), Methods. Cells were treated with 1 mmol/L hydrogen peroxide (H2O2) Or were grown in control medium for 24 hours. Cell death (apoptosis) was quantitated using defined morphological criteria. DNA gel electrophoresis was used for biochemical identification. Protein expression levels and cellular localization of the selected Bcl-2 family proteins were analyzed (West ern immunoblots, densitometry, immunoelectron microscopy). Results. Apoptosis was minimal in control cultures and was greatest in treated proximal cell cultures (16.93 +/- 4.18% apoptosis) compared with treated distal cell cultures (2.28 +/- 0.85% apoptosis, P < 0.001). Endogenous expression of Bcl-X-L and Bax, but not Bcl-2 or Bad, was identified in control distal cells, Bcl-X-L and Bax had nonsignificant increases (P > 0.05) in these cells. Bcl-2, Bax, and Bcl-X-L, but not Bad, were endogenously expressed in control proximal cells. Bcl-X-L was significantly decreased in treated proximal cultures (P < 0.05), with Bas and Bcl-2 having nonsignificant increases (P > 0.05). Immunoelectron microscopy localization indicated that control and treated hut surviving proximal cells had similar cytosolic and membrane localization of the Bcl-2 proteins. In comparison, surviving cells in the treated distal cultures showed translocation of Bcl-X-L from cytosol to the mitochondria after treatment with H2O2, a result that was confirmed using cell fractionation and analysis of Bcl-XL expression levels of the membrane and cytosol proteins. Bax remained distributed evenly throughout the surviving distal cells, without particular attachment to any cellular organelle. Conclusion. The results indicate that in this in vitro model, the increased survival of distal compared with proximal tubular cells after oxidative stress is best explained by the decreased expression of anti-apoptotic Bcl-X-L in proximal cells, as well as translocation of Bcl-X-L protein to mitochondria within the surviving distal cells.

Virulence of Streptococcus pneumoniae: PsaA mutants are hypersensitive to oxidative stress

psaA encodes a 37-kDa pneumococcal lipoprotein which is part of an ABC Mn(II) transport complex. Streptococcus pneumoniae D39 psaA mutants have previously been shown to be significantly less virulent than wild-type D39, but the mechanism underlying the attenuation has not been resolved. In this study, we have shown that psaA and psaD mutants are highly sensitive to oxidative stress, i.e., to superoxide and hydrogen peroxide, which might explain why they are less virulent than the wild-type strain. Our investigations revealed altered expression of the key oxidative-stress response enzymes superoxide dismutase and NADH oxidase in psaA and psaD mutants, suggesting that PsaA and PsaD may play important roles in the regulation of expression of oxidative-stress response enzymes and intracellular redox homeostasis.

Oxidative stress is responsible for deficient survival and dendritogenesis in Purkinje neurons from ataxia-telangiectasia mutated mutant mice

Atm gene-disrupted mice recapitulate the majority of characteristics observed in patients with the genetic disorder ataxia-telangiectasia (A-T). However, although they exhibit defects in neuromotor function and a distinct neurological phenotype, they do not show the progressive neurodegeneration seen in human patients, but there is evidence that ataxia-telangiectasia mutated ( Atm)-deficient animals have elevated levels of oxidized macromolecules and some neuropathology. We report here that in vitro survival of cerebellar Purkinje cells from both Atm knock-out and Atm knock-in mice was significantly reduced compared with their wild-type littermates. Although most of the Purkinje neurons from wild-type mice exhibited extensive dendritic elongation and branching under these conditions, most neurons from Atm-deficient mice had dramatically reduced dendritic branching. An antioxidant ( isoindoline nitroxide) prevented Purkinje cell death in Atm-deficient mice and enhanced dendritogenesis to wild-type levels. Furthermore, administration of the antioxidant throughout pregnancy had a small enhancing effect on Purkinje neuron survival in Atm gene-disrupted animals and protected against oxidative stress in older animals. These data provide strong evidence for a defect in the cerebellum of Atm-deficient mice and suggest that oxidative stress contributes to this phenotype.

A Sco homologue plays a role in defence against oxidative stress in pathogenic Neisseria

Sco proteins are found in mitochondria and in a variety of oxidase positive bacteria. Although Sco is required for the formation of the Cu-A centre in a cytochrome oxidase of the aa(3) type, it was observed that oxidases with a Cu-A centre are not present in many bacteria that contain a Sco homologue. Two bacteria of this type are the pathogens Neisseria meningitidis and Neisseria gonorrhoeae. The sco genes of N. gonorrhoeae strain 1291 and N. meningitidis strain MC58 were cloned, inactivated by inserting a kanamycin resistance cassette and used to make knockout mutants by allelic exchange. Both N. gonorrhoeae and N. meningitidis sco mutants were highly sensitive to oxidative killing by paraquat, indicating that Sco is involved in protection against oxidative stress in these bacteria. (C) 2003 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.

Effect of oxidative stress upon absorption of glucose by the human placenta: in vitro studies with BeWo cells

Pregnancy is a dynamic state and the placenta is a temporary organ that, among other important functions, plays a crucial role in the transport of nutrients and metabolites between the mother and the fetus, which is essential for a successful pregnancy. Among these nutrients, glucose is considered a primary source of energy and, therefore, fundamental to insure proper fetus development. Several studies have shown that glucose uptake is dependent on several morphological and biochemical placental conditions. Oxidative stress results from the unbalance between reactive oxygen species (ROS) and antioxidants, in favor of the first. During pregnancy, ROS, and therefore oxidative stress, increase, due to increased tissue oxygenation. Moreover, the relation between ROS and some pathological conditions during pregnancy has been well established. For these reasons, it becomes essential to understand if oxidative stress can compromise the uptake of glucose by the placenta. To make this study possible, a trophoblastic cell line, the BeWo cell line, was used. Experiments regarding glucose uptake, either under normal or oxidative stress conditions, were conducted using tert-butylhydroperoxide (tBOOH) as an oxidative stress inducer, and 3H-2-deoxy-D-glucose (3H-DG) as a glucose analogue. Afterwards, studies regarding the involvement of glucose facilitative transporters (GLUT) and the phosphatidylinositol 3-kinases (PI3K) and protein kinase C (PKC) pathways were conducted, also under normal and oxidative stress conditions. A few antioxidants, endogenous and from diet, were also tested in order to study their possible reversible effect of the oxidative effect of tBOOH upon apical 3H-DG uptake. Finally, transepithelial studies gave interesting insights regarding the apical-to-basolateral transport of 3H-DG. Results showed that 3H-DG uptake, in BeWo cells, is roughly 50% GLUT-mediated and that tBOOH (100 μM; 24h) decreases apical 3H-DG uptake in BeWo cells by about 33%, by reducing both GLUT- (by 28%) and non-GLUT-mediated (by 40%) 3H-DG uptake. Uptake of 3H-DG and the effect of tBOOH upon 3H-DG uptake are not dependent on PKC and PI3K. Moreover, the effect of tBOOH is not associated with a reduction in GLUT1 mRNA levels. Resveratrol, quercetin and epigallocatechin-3-gallate, at 50 μM, reversed, by at least 45%, the effect of tBOOH upon 3H-DG uptake. Transwell studies show that the apical-to-basolateral transepithelial transport of 3H-DG is increased by tBOOH.In conclusion, our results show that tBOOH caused a marked decrease in both GLUT and non-GLUT-mediated apical uptake of 3H-DG by BeWo cells. Given the association of increased oxidative stress levels with several important pregnancy pathologies, and the important role of glucose for fetal development, the results of this study appear very interesting.

Metal accumulation and oxidative stress biomarkers in octopus (Octopus vulgaris) from Northwest Atlantic

Metals are ubiquitous in the environment and accumulate in aquatic organisms and are known for their ability to enhance the production of reactive oxygen species (ROS). In aquatic species, oxidative stress mechanisms have been studied by measuring antioxidant enzyme activities and oxidative damages in tissues. The aim of this study was to apply and validate a set of oxidative stress biomarkers and correlate responses with metal contents in tissues of common octopus (Octopus vulgaris). Antioxidant enzyme activity (catalase — CAT, superoxide dismutase — SOD and glutathione S-transferases — GST), oxidative damages (lipid peroxidation — LPO and protein carbonyl content — PCO) andmetal content (Cu, Zn, Pb, Cd and As) in the digestive gland and armof octopus, collected in the NWPortuguese coast in different periods, were assessed after capture and after 14 days in captivity. CAT and SOD activitieswere highly responsive to fluctuations inmetal concentrations and able to reduce oxidative damage, LPO and PCO in the digestive gland. CAT activity was also positively correlated with SOD and GST activities, which emphasizes that the three enzymes respond in a coordinated way to metal induced oxidative stress. Our results validate the use of oxidative stress biomarkers to assess metal pollution effects in this ecological and commercial relevant species.Moreover, octopus seems to have the ability to control oxidative damage by triggering an antioxidant enzyme coordinated response in the digestive gland.

Protection against oxidative stress through SUA7/TFIIB regulation in Saccharomyces cerevisiae

The general transcription factor TFIIB, encoded by SUA7 in Saccharomyces cerevisiae, is required for transcription activation but apparently of a specific subset of genes, for example, linked with mitochondrial activity and hence with oxidative environments. Therefore, studying SUA7/TFIIB as a potential target of oxidative stress is fundamental. We found that controlled SUA7 expression under oxidative conditions occurs at transcriptional and mRNA stability levels. Both regulatory events are associated with the transcription activator Yap1 in distinct ways: Yap1 affects SUA7 transcription up regulation in exponentially growing cells facing oxidative signals; the absence of this activator per se contributes to increase SUA7 mRNA stability. However, unlike SUA7 mRNA, TFIIB abundance is not altered on oxidative signals. The biological impact of this preferential regulation of SUA7 mRNA pool is revealed by the partial suppression of cellular oxidative sensitivity by SUA7 overexpression, and supported by the insights on the existence of a novel RNA-binding factor, acting as an oxidative sensor, which regulates mRNA stability. Taken together the results point out a primarily cellular commitment to guarantee SUA7 mRNA levels under oxidative environments.

Adverse effect of alcohol drinking: the role of oxidative stress

Atualmente, o álcool tem um papel importante na saúde pública e surge como um dos principais problemas sociais no mundo, dado que é a droga mais viciante aceite em encontros sociais. Provavelmente, por essa razão, os riscos do consumo abusivo do álcool são subestimados pelos jovens, mulheres grávidas e idosos. O álcool, quando ingerido em altas proporções, pode afetar todos os órgãos e desencadear inúmeras doenças, tais como a doença cardíaca coronariana, doença neurodegenerativa, as doenças crónicas e câncer. O álcool afeta ainda o estado psicológico, induzindo a violência, o estado antissocial e situações de risco de comportamentos. Por estas razões, o álcool tornou-se um foco principal da investigação, avaliando os seus efeitos sobre o corpo humano. Nesta pesquisa, foram suscitadas amostras de sangue de um grupo de pacientes em tratamento psicológico e/ou farmacêutico que serão analisadas com quatro métodos: Teste de Radicais Livres do Oxigénio (FORT), Defesa contra Radicais Livres do Oxigénio (FORD), cromatografia gasosa (GC) e cromatografia líquida de alta pressão (HPLC). Ambos os métodos FORT e FORD avaliam o stress oxidativo pela quantificação de radicais livres e a capacidade de antioxidantes em eliminar esses radicais livres, respetivamente. O stress oxidativo é o efeito do excesso de consumo de álcool, que é reduzido pela capacidade de ação dos antioxidantes. A boa reprodutibilidade, precisão e exatidão de ambos os métodos indicam que estes podem ser aplicados em rápidos diagnósticos. Para o método FORT e considerando o início do tratamento, os pacientes alcoólicos apresentaram uma média de 3,59±1.01mmol/LH2O2 e o grupo de controlo uma média de 1,42±0.53mmol/LH2O2, o que mostra uma diferença significativa entre os dois grupos (P=0,0006). Para o método FORD, pacientes alcoólicos apresentam uma média de 1,07±0.53mmol/LH2O2 e o grupo de controlo, uma média de 2,81±0.46mmol/LH2O2, mostrando também uma média significativa (P=0,0075). Após 15 dias de tratamento observou-se que há uma diferença entre os dois grupos de pacientes alcoólicos, mas não há nenhum melhoramento em relação ao grupo de pacientes em tratamento. No método FORT os grupos mostram uma diferença significativa (P=0,0073), tendo os pacientes sem tratamento farmacêutico melhores resultados (2.37±0.44mmol/LH2O2) do que os pacientes com tratamento (3.72±1,04mmol/LH2O2). O oposto ocorre no método FORD, os pacientes em tratamento farmacêutico presentam melhores resultados (1.16±0.65mmol/LH2O2) do que o outro grupo (0.75±0.22mmol/LH2O2), não sendo, no entanto, uma diferença significativa entre os dois grupos (P=0.16). Os resultados obtidos para a concentração de MDA pelo método de HPLC mostraram que o grupo de controlo tem valores mais baixos do que os pacientes alcoólicos, embora a diferença não seja muito significativa (P = 0,084), mas é ainda elevada. Além disso, os dois grupos de pacientes não apresentaram uma diferença significativa entre os seus resultados no início (P=0,77) e no fim (P=0,79) do tratamento. De acrescentar ainda que, os resultados da concentração de álcool no sangue determinados pelo método de CG mostraram que só alguns pacientes sem tratamento consumiram álcool durante o período de tratamento, o que influencia negativamente a conclusão sobre o efeito do tratamento. Contudo, outros fatores externos podem ainda influenciar os resultados finais, tais como o estado nutricional e estado psicológico dos pacientes, se o paciente continua a beber durante o tempo de tratamento ou até mesmo se o paciente é exposto a outros tipos de substâncias nocivas. Existe ainda a possibilidade de o tempo de aplicação do tratamento não ser suficiente para apresentar um efeito positivo em relação ao stress oxidativo e este é um outro fator que contribui para a impossibilidade de confirmar sobre o efeito, quer seja positivo ou negativo, do tratamento antioxidante.

Mitochondria are the main source and one of the targets of Pb (lead)-induced oxidative stress in the yeast Saccharomyces cerevisiae

The yeast Saccharomyces cerevisiae is a useful model organism for studying lead (Pb) toxicity. Yeast cells of a laboratory S. cerevisiae strain (WT strain) were incubated with Pb concentrations up to 1,000 μmol/l for 3 h. Cells exposed to Pb lost proliferation capacity without damage to the cell membrane, and they accumulated intracellular superoxide anion (O2 .−) and hydrogen peroxide (H2O2). The involvement of the mitochondrial electron transport chain (ETC) in the generation of reactive oxygen species (ROS) induced by Pb was evaluated. For this purpose, an isogenic derivative ρ0 strain, lacking mitochondrial DNA, was used. The ρ0 strain, without respiratory competence, displayed a lower intracellular ROS accumulation and a higher resistance to Pb compared to the WT strain. The kinetic study of ROS generation in yeast cells exposed to Pb showed that the production of O2 .− precedes the accumulation of H2O2, which is compatible with the leakage of electrons from the mitochondrial ETC. Yeast cells exposed to Pb displayed mutations at the mitochondrial DNA level. This is most likely a consequence of oxidative stress. In conclusion, mitochondria are an important source of Pb-induced ROS and, simultaneously, one of the targets of its toxicity.

Oxidative stress in pregnancy and fertility pathologies

Oxidative stress designates the state of imbalance between reactive oxygen species (ROS) production and antioxidant levels. In a healthy placenta, there is an increase in ROS production, due to formation of new tissues and inherent metabolism, but this is balanced by higher levels of antioxidants. However, this balance is lost in some situations, with a consequent increase in oxidative stress levels. Oxidative stress has been implicated in several placental disorders and pregnancy pathologies. The present review intends to summarize what is known about the relationship between oxidative stress and well-known pregnancy disorders.

Disposable immunosensor using a simple method for oriented antibody immobilization for label-free real-time detection of an oxidative stress biomarker implicated in cancer diseases

This work proposes a novel approach for a suitable orientation of antibodies (Ab) on an immunosensing platform, applied here to the determination of 8-hydroxy-2′-deoxyguanosine (8OHdG), a biomarker of oxidative stress that has been associated to chronic diseases, such as cancer. The anti-8OHdG was bound to an amine modified gold support through its Fc region after activation of its carboxylic functions. Non-oriented approaches of Ab binding to the platform were tested in parallel, in order to show that the presented methodology favored Ab/Ag affinity and immunodetection of the antigen. The immunosensor design was evaluated by quartz-crystal microbalance with dissipation, atomic force microscopy, electrochemical impedance spectroscopy (EIS) and square-wave voltammetry. EIS was also a suitable technique to follow the analytical behavior of the device against 8OHdG. The affinity binding between 8OHdG and the antibody immobilized in the gold modified platform increased the charge transfer resistance across the electrochemical set-up. The observed behavior was linear from 0.02 to 7.0 ng/mL of 8OHdG concentrations. The interference from glucose, urea and creatinine was found negligible. An attempt of application to synthetic samples was also successfully conducted. Overall, the presented approach enabled the production of suitably oriented Abs over a gold platform by means of a much simpler process than other oriented-Ab binding approaches described in the literature, as far as we know, and was successful in terms of analytical features and sample application.