Oxidative-nitrative Stress Research Articles

Fruit extracts of various cornelian cherry (Cornus mas L.) cultivars as antioxidant therapy for alleviating nitrative stress in erythrocytes of blood in experimental diabetes mellitus

Natural antioxidants (vitamins, bioflavonoids, anthocyanins, etc.) are used to prevent the development of oxidative-nitrative stress in diabetes mellitus (DM), which helps to restore or avert functional disorders in the cells and tissues of the body. The aim of the study is to investigate the effect of extracts of the fruit of different cultivars of the cornelian cherry, as well as their main iridoid glycoside – loganic acid, on the activity of NO-synthase and the content of stable metabolites of NO in blood erythrocytes of rats with streptozotocin-induced diabetes. Materials and methods. In the work, we used the extract of the fruits of the cornelian cherry “Podolski” cultivar (BDPA 10462), the ripe fruits of which have a red color, and the extract of the “Yantarnyi” (BDPA 14131) and “Flava” (BDPA 8795) cultivars, the ripe fruits of which have a yellow color. Loganic acid was extracted from yellow fruits of the “Yantarnyi” and “Flava” cultivars of Cornus mas L. All studied extracts were administered to rats orally for 14 days from the 10th day after the induction of DM. The dose of administration was 20 mg/kg body weight. Results. The extract of the red fruits is demonstrated the most pronounced effect in normalizing the biomarkers of nitrative stress (activity of NO-synthase and its isoforms, the content of nitrite and nitrate anions) in erythrocytes of rats with diabetes. The extract of the yellow fruits shows a positive effect on the suppression of nitrative stress, which has been indicated by a decrease in the activity of iNO-synthase to the values in the control group of animals. Loganic acid, on the contrary, inhibited the eNO-synthase. In addition, the extract of yellow fruits of cornelian cherry and loganic acid decreased the level of NO3– and increased the content of NO2– in erythrocytes of diabetic rats. Conclusions. Biomarkers of nitrative stress in erythrocytes of rats with streptozotocin-induced diabetes indicated the antioxidant properties of fruit extracts of cornelian cherry, in particular the red fruits, which contain a large amount of anthocyanins.

The impact of grape pomace extract rich in natural complex of polyphenols on morpho-functional state of leukocytes under experimental diabetes mellitus

Background. Diabetes mellitus is one of the most common diseases in the world. Under this pathology all organs and systems of an organism are damaged, inclu­ding the immune system. Peripheral blood leukocytes are an important element of this system that suffer damage under diabetes mellitus due to the influence of reactive oxygen species and reactive nitrogen species, the number of which increases fast and leads to the development of oxidative-nitrative stress. Thus, the discovery of new diabetes-correcting drugs that possess hypoglycemic, antioxidant and immunomodulatory proper­ties is one of the principal tasks. Such properties are inherent in polyphenolic compounds, a large amount of which is contained in the grape pomace. That is why the study of grape pomace extract, rich in a natural complex of polyphenols, is important to evaluate the possibility of further use of these substances as a basis for drugs that can be used in the complex therapy of diabetes mellitus. Materials and Methods. The research used peripheral blood leukocytes of the control rats, the control animals that were treated with grape pomace extract for 14 days, animals with streptozotocin-induced diabetes mellitus and rats with experimental diabetes mellitus that were treated with grape pomace extract for 14 days. To evaluate the corrective effect of the grape pomace extract rich in a natural complex of polyphenols on the state of the antioxidant defense and the L-arginine/NO systems, the activity of antioxidant enzymes, the level of oxidative modification products of proteins and lipids, the activity of NO-synthase, the content of nitrites and nitrates, 3ʹ-nitrotyrosine-modified proteins were studied. The total number of leukocytes, the white blood cell differential and the phagocytic activity, and the average cytochemical coefficients of cationic proteins and NADPH-oxidase activity were indicated to study the effect of the grape pomace extract on the functional state of leukocytes. Results and Discussion. The study revealed normalization of the total number of leukocytes and the white blood cell differential, the activity of NADPH-oxidase, superoxide dismutase, catalase and glutathione peroxidase, and the levels of the oxidative modification products of proteins and lipids, nitrites, nitrates and 3ʹ-nitrotyrosine-modified proteins, as well as an increase in the average cytochemical coefficient of cationic proteins, and a decrease of the inducible NO-synthase activity after grape pomace extract administration for 14 days to animals with streptozotocin-induced diabetes mellitus. Conclusion. The obtained results confirm the antioxidant and immunomodulatory effects of the studied extract and justify the feasibility of using grape pomace complex of polyphenolic compounds as a basis for new drugs that will be used in the complex therapy of diabetes mellitus.

PARP2 downregulation in T cells ameliorates lipopolysaccharide-induced inflammation of the large intestine.

T cell-dependent inflammatory response with the upregulation of helper 17 T cells (Th17) and the downregulation of regulatory T cells (Treg) accompanied by the increased production of tumor necrosis alpha (TNFa) is characteristic of inflammatory bowel diseases (IBD). Modulation of T cell response may alleviate the inflammation thus reduce intestinal damage. Poly(ADP-ribose) polymerase-2 (PARP2) plays role in the development, differentiation and reactivity of T cell subpopulations. Our aim was to investigate the potential beneficial effect of T cell-specific PARP2 downregulation in the lipopolysaccharide (LPS) induced inflammatory response of the cecum and the colon. Low-dose LPS was injected intraperitoneally to induce local inflammatory response, characterized by increased TNFa production, in control (CD4Cre; PARP2+/+) and T cell-specific conditional PARP2 knockout (CD4Cre; PARP2f/f) mice. TNFa, IL-1b, IL-17 levels were measured by ELISA, oxidative-nitrative stress was estimated by immunohistochemistry, while PARP1 activity, p38 MAPK and ERK phosphorylation, and NF-kB expression in large intestine tissue samples were examined by Western-blot. Systemic & local T cell subpopulation; Th17 and Treg alterations were also investigated using flowcytometry and immunohistochemistry. In control animals, LPS induced intestinal inflammation with increased TNFa production, while no significant elevation of TNFa production was observed in T cell-specific PARP2 knockout animals. The absence of LPS-induced elevation in TNFa levels was accompanied by the absence of IL-1b elevation and the suppression of IL-17 production, showing markedly reduced inflammatory response. The increase in oxidative-nitrative stress and PARP1-activation was also absent in these tissues together with altered ERK and NF-kB activation. An increase in the number of the anti-inflammatory Treg cells in the intestinal mucosa was observed in these animals, together with the reduction of Treg count in the peripheral circulation. Our results confirmed that T cell-specific PARP2 downregulation ameliorated LPS-induced colitis. The dampened TNFa production, decreased IL-17 production and the increased intestinal regulatory T cell number after LPS treatment may be also beneficial during inflammatory processes seen in IBD. By reducing oxidative-nitrative stress and PARP1 activation, T cell-specific PARP2 downregulation may also alleviate intestinal tissue damage.

Delta 9-tetrahydrocannabinol conserves cardiovascular functions in a rat model of endotoxemia: Involvement of endothelial molecular mechanisms and oxidative-nitrative stress.

In endotoxemic models, the inflammatory parameters are altered to a favorable direction as a response to activation of cannabinoid receptors 1 and 2. The phytocannabinoid Δ9-tetrahydrocannabinol (THC) is an agonist/partial antagonist of both cannabinoid receptors. This report targets the effects of THC on the cardiovascular system of endotoxemic rats. In our 24-hour endotoxemic rat model (E. coli derived lipopolysaccharide, LPS i.v. 5mg/kg) with THC treatment (LPS+THC 10 mg/kg i.p.), we investigated cardiac function by echocariography and endothelium-dependent relaxation of the thoracic aorta by isometric force measurement compared to vehicle controls. To evaluate the molecular mechanism, we measured endothelial NOS and COX-2 density by immunohistochemistry; and determined the levels of cGMP, the oxidative stress marker 4-hydroxynonenal, the nitrative stress marker 3-nitrotyrosine, and poly(ADP-ribose) polymers. A decrease in end-systolic and end-diastolic ventricular volumes in the LPS group was observed, which was absent in LPS+THC animals. Endothelium-dependent relaxation was worsened by LPS but not in the LPS+THC group. LPS administration decreased the abundance of cannabinoid receptors. Oxidative-nitrative stress markers showed an increment, and cGMP, eNOS staining showed a decrement in response to LPS. THC only decreased the oxidative-nitrative stress but had no effect on cGMP and eNOS density. COX-2 staining was reduced by THC. We hypothesize that the reduced diastolic filling in the LPS group is a consequence of vascular dysfunction, preventable by THC. The mechanism of action of THC is not based on its local effect on aortic NO homeostasis. The reduced oxidative-nitrative stress and the COX-2 suggest the activation of an anti-inflammatory pathway.

A Review on: Alzheimer’s disease and mechanistic insights of bioactive compounds in its treatment

Alzheimer’s disease is a most common neurological disorder, associated with cognitive disorder. Pathologically, Alzheimer's disease is characterized via the presence of β-amyloid (Aβ) plaques, hyper-phosphorylated tau proteins, and neurofibrillary tangles, but persistence oxidative-nitrative stress, endoplasmic reticulum pressure, mitochondrial disorder, inflammatory cytokines, pro-apoptotic proteins in conjunction with altered neurotransmitters degree are common etiological attributes in its pathogenesis. With the modern state of affairs, the variety of published proofs shows the neuroprotective capability of evidently occurring bioactive molecule via their anti-oxidant, ant apoptotic and neutransmitter modulatory residences. Many researchers have counselled that change of life style, proper diet, can delay or prevent the onset of this ailment. Diet is presently considered to be an important component in controlling fitness and protecting oneself towards oxidative strain and persistent inflammation, and hence towards chronic degenerative illnesses. A wide variety of bioactive food compounds may impact the pathological mechanisms underlying AD. Among them, phenolic compounds, omega-three fatty acids, fats-soluble vitamins, isothiocyanates, seem like the best in stopping neurodegeneration. The present review gathers proof that helps the neuroprotective impact of bioactive materials. Keywords: Alzheimer’s disease, neurodegeneration, amyloid cascade, tau protein, tau hypothesis, nitric oxide

Mucoprotective and Mast Cell Stabilization Activities of Chromium (D-Phenylalanine)3 in Indomethacin-Induced Chronic Enterocolitis in Rats: In vitro Anti-Cancer Activity Using Caco-2 Cell Line

Objective The current research work was intended to establish the positive effects of chromium complex CrD-phe3 in indomethacin induced chronic enterocolitis. Additionally Caco-2 was used to elucidate the anti-cancer property of the title compound.Methodology Oral administration of indomethacin 1.5 mgkg twice quotidian for fourteen days was done to induce chronic enterocolitis in rats. Pre-treatment with chromium complex 30 amp 60 mugkg p.o for three days before induction was done and this continued up to the end of the study. Macroscopic scoring of the stomach jejunum and ileum was done to analyze the extent of damage and inflammation. Mesenteric mast cell degranulation counts serum and ileum tissue biochemical estimations and histopathological analysis were carried out. MTT assay was performed to identify the cytotoxicity of Cr D-Phe3 using Caco-2 cells.Results Oral administration of CrD-phe3 displayed a substantial reduction in the elevated macroscopical scores oxidative-nitrative stress biochemical parameters and mast cell degranulation induced by chronic treatment of indomethacin. The protective effect of the chromium complex was also established through histological inspection of the ileum. Further treatment of the title complex resulted in Caco-2 cell viability reduction and exhibited IC50 722.40 mM.Conclusion The pragmatic usefulness of the chromium complex might be owed to its antioxidative anti-inflammation anti-allergic and mucoprotective properties. In addition the title complex exhibited anticolorectal cancer.nbsp

Network analysis of the left anterior descending coronary arteries in swim-trained rats by an in situ video microscopic technique

BackgroundWe aimed to identify sex differences in the network properties and to recognize the geometric alteration effects of long-term swim training in a rat model of exercise-induced left ventricular (LV) hypertrophy.MethodsThirty-eight Wistar rats were divided into four groups: male sedentary, female sedentary, male exercised and female exercised. After training sessions, LV morphology and function were checked by echocardiography. The geometry of the left coronary artery system was analysed on pressure-perfused, microsurgically prepared resistance artery networks using in situ video microscopy. All segments over > 80 μm in diameter were studied using divided 50-μm-long cylindrical ring units of the networks. Oxidative-nitrative (O-N) stress markers, adenosine A2A and estrogen receptor (ER) were investigated by immunohistochemistry.ResultsThe LV mass index, ejection fraction and fractional shortening significantly increased in exercised animals. We found substantial sex differences in the coronary network in the control groups and in the swim-trained animals. Ring frequency spectra were significantly different between male and female animals in both the sedentary and trained groups. The thickness of the wall was higher in males as a result of training. There were elevations in the populations of 200- and 400-μm vessel units in males; the thinner ones developed farther and the thicker ones closer to the orifice. In females, a new population of 200- to 250-μm vessels appeared unusually close to the orifice.ConclusionsPhysical activity and LV hypertrophy were accompanied by a remodelling of coronary resistance artery network geometry that was different in both sexes.

Nutraceuticals and their Derived Nano-Formulations for the Prevention and Treatment of Alzheimer's Disease.

Alzheimer's disease (AD) is one of the common chronic neurological disorders and associated with cognitive dysfunction, depression and progressive dementia. The presence of β-amyloid or senile plaques, hyper-phosphorylated tau proteins, neurofibrillary tangle, oxidative-nitrative stress, mitochondrial dysfunction, endoplasmic reticulum stress, neuroinflammation and derailed neurotransmitter status are the hallmarks of AD. Currently, donepezil, memantine, rivastigmine and galantamine are approved by the FDA for symptomatic management. It is well-known that these approved drugs only exert symptomatic relief and possess poor patient-compliance. Additionally, various published evidence showed the neuroprotective potential of various nutraceuticals via their antioxidant, anti-inflammatory and anti-apoptotic effects in the preclinical and clinical studies. These nutraceuticals possess a significant neuroprotective potential and hence, can be a future pharmacotherapeutic for the management and treatment of AD. However, nutraceuticals suffer from certain major limitations such as poor solubility, low bioavailability, low stability, fast hepatic- metabolism and larger particle size. These pharmacokinetic attributes restrict their entry into the brain via the blood-brain barrier. Therefore, to overcome such issues, various nanoformulations of nutraceuticals have been developed, that allow their effective delivery into the brain owing to reduced particle size, increased lipophilicity, increased bioavailability and avoidance of fast hepatic metabolism. Thus, in this review, we have discussed the etiology of AD, focusing on the pharmacotherapeutics of nutraceuticals with preclinical and clinical evidence, discussed pharmaceutical limitations and regulatory aspects of nutraceuticals to ensure safety and efficacy. We have further explored various nanoformulations of nutraceuticals as a novel approach to overcome the existing pharmaceutical limitations and for effective delivery into the brain.

Corrective effect of red wine concentrate enriched with natural complex of polyphenols on activity of antioxidant defense enzymes in cardiac muscle under experimental diabetes mellitus

Background. Diabetes mellitus is accompanied by oxidative-nitrative stress, which is caused both by an increased generation of the Reactive Oxygen Species and the Reactive Nitrogen Species under the conditions of this pathology and by the disorders of the antioxidant defense system, especially its enzymatic part. This leads alterations in the morpho-functional state of cells, organs, and the whole organism. Free radicals are involved in the destruction of pancreatic cells in type 1 diabetes mellitus, which leads to even greater inhibition of insulin secretion, worsening of the course of the disease and occurrence of diabetic complications. The complications of diabetes mellitus include often diagnosed cardiovascular diseases. Therefore, the use of treatments characterized not only by hypoglycemic properties for normalization of blood sugar level in diabetes mellitus, but also by antioxidant properties for normalization of oxidative/antioxidant balance of the organism in the studied pathology can be promising. Scientists pay a great attention to the study of substances with such properties, especially natural phenolic compounds of grape, which are also characterized by immunomodulatory properties. Materials and Methods. The study was performed on cardiac tissues of control rats, control animals treated with wine polyphenolic complex concentrate, animals with streptozotocin-induced diabetes mellitus and animals with experimental diabetes mellitus treated with a concentrate of wine polyphenolic complex. The activity of catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase were detected to examine the corrective effect of the concentrate of red wine natural polyphenolic comp­lex on the state of the enzymatic part of the antioxidant defense system. Results. The results have shown the normalization of activity of catalase, superoxide dismutase, and changes in the activity of enzymes of glutathione cycle after oral administration of polyphenolic complex concentrate for 14 days to rats with streptozo­tocin-induced diabetes mellitus. Conclusions. The results confirm a hypothesis about the antioxidant effect of the studied concentrate and the ability of natural polyphenolic complexes to serve as the basis for new drugs for treatment of diabetes-induced disorders.

Current Quest in Natural Bioactive Compounds for Alzheimer's Disease: Multi-Targeted-Designed-Ligand Based Approach with Preclinical and Clinical Based Evidence.

Alzheimer's disease is a common and most chronic neurological disorder (NDs) associated with cognitive dysfunction. Pathologically, Alzheimer's disease (AD) is characterized by the presence of β-amyloid (Aβ) plaques, hyper-phosphorylated tau proteins, and neurofibrillary tangles, however, persistence oxidative-nitrative stress, endoplasmic reticulum stress, mitochondrial dysfunction, inflammatory cytokines, pro-apoptotic proteins along with altered neurotransmitters level are common etiological attributes in its pathogenesis. Rivastigmine, memantine, galantamine, and donepezil are FDA approved drugs for symptomatic management of AD, whereas tacrine has been withdrawn because of hepatotoxic profile. These approved drugs only exert symptomatic relief and exhibit poor patient compliance. In the current scenario, the number of published evidence shows the neuroprotective potential of naturally occurring bioactive molecules via their antioxidant, anti-inflammatory, antiapoptotic and neurotransmitter modulatory properties. Despite their potent therapeutic implications, concerns have arisen in context to their efficacy and probable clinical outcome. Thus, to overcome these glitches, many heterocyclic and cyclic hydrocarbon compounds inspired by natural sources have been synthesized and showed improved therapeutic activity. Computational studies (molecular docking) have been used to predict the binding affinity of these natural bioactive as well as synthetic compounds derived from natural sources for the acetylcholine esterase, α/β secretase Nuclear Factor kappa- light-chain-enhancer of activated B cells (NF-kB), Nuclear factor erythroid 2-related factor 2(Nrf2) and other neurological targets. Thus, in this review, we have discussed the molecular etiology of AD, focused on the pharmacotherapeutics of natural products, chemical and pharmacological aspects and multi-targeted designed ligands (MTDLs) of synthetic and semisynthetic molecules derived from the natural sources along with some important on-going clinical trials.

Agmatine Prevents Oxidative-nitrative Stress in Blood Leukocytes Under Streptozotocin-induced Diabetes Mellitus.

Changes in cellular metabolism, development of oxidative-nitrative stress and intensification of glycation and lipid peroxidation (LPO), are significant processes that occur during diabetes mellitus (DM)-associated chronic hyperglycemia. These processes contribute to deviations in the structural organization and functional activity of leukocytes. The development of oxidative-nitrative stress in peripheral blood cells during DM can be prevented by agmatine, an endogenous metabolite of L-arginine, which is a nitric oxide synthase (NOS) inhibitor, and possesses hypoglycemic properties. The administration of agmatine to animals with DM lead to the inhibition of both constitutive and inducible NOS in leukocytes, which in turn decreased total nitrite/nitrate (NOx) levels. Additionally, we observed corresponding increases in reduced glutathione content and activity of antioxidant enzymes (SOD, CAT, GPx, GR), along with decreased levels of the thiobarbituric acid reactive substance, advanced oxidation protein products (AOPPs) and advanced glycosylation end-products (AGEs) as compared to the non-treated diabetic group. Our results indicate that treatment of diabetic animals with agmatine restores redox homeostasis and a balances antioxidant defence system enzymes in leukocytes. This corrective effect on the functional capacity of leukocytes is exerted by preventing oxidative-nitrative stress in animals with DM.

Oxidative-Nitrative Stress and Poly (ADP-Ribose) Polymerase Activation 3 Years after Pregnancy.

Background Oxidative-nitrative stress and poly (ADP-ribose) polymerase activation have been previously observed in healthy and gestational diabetic pregnancies, and they were also linked to the development of metabolic diseases. The aim of the present study was to examine these parameters and their correlation to known metabolic risk factors following healthy and gestational diabetic pregnancies. Methods Fasting and 2 h postload plasma total peroxide level, protein tyrosine nitration, and poly (ADP-ribose) polymerase activation were measured in circulating leukocytes three years after delivery in women following healthy, “mild” (diet-treated) or “severe” (insulin-treated) gestational diabetic pregnancy during a standard 75 g OGTT. Nulliparous women and men served as control groups. Results Fasting plasma total peroxide level was significantly elevated in women with previous pregnancy (B = 0.52 ± 0.13; p < 0.001), with further increase in women with insulin-treated gestational diabetes (B = 0.36 ± 0.17; p < 0.05) (R2 = 0.419). Its level was independently related to previous pregnancy (B = 0.47 ± 0.14; p < 0.01) and current CRP levels (B = 0.06 ± 0.02; p < 0.05) (R2 = 0.306). Conclusions Elevated oxidative stress but not nitrative stress or poly (ADP-ribose) polymerase activation can be measured three years after pregnancy. The increased oxidative stress may reflect the cost of reproduction and possibly play a role in the increased metabolic risk observed in women with a history of severe gestational diabetes mellitus.

Oxidative Stress-Related Parthanatos of Circulating Mononuclear Leukocytes in Heart Failure.

Background The present study aims to examine the oxidative stress-related activation of poly(ADP-ribose) polymerase (PARP), a cause of parthanatos in circulating mononuclear leukocytes of patients with chronic heart failure (CHF), that was rarely investigated in the human setting yet. Methods Patients with CHF (n = 20) and age- and body mass index-matched volunteers (n = 15) with a normal heart function were enrolled. C-reactive protein, N-terminal probrain-type natriuretic peptide (pro-BNP), plasma total peroxide level (PRX), plasma total antioxidant capacity (TAC), oxidative stress index (OSI), leukocyte lipid peroxidation (4-hydroxynonenal; HNE), protein tyrosine nitration (NT), poly(ADP-ribosyl)ation (PARylation), and apoptosis-inducing factor (AIF) translocation were measured in blood samples of fasting subjects. Results Plasma PRX, leukocyte HNE, NT, PARylation, and AIF translocation were significantly higher in the heart failure group. Pro-BNP levels in all study subjects showed a significant positive correlation to PRX, OSI, leukocyte HNE, NT, PARylation, and AIF translocation. Ejection fraction negatively correlated with the same parameters. Among HF patients, a positive correlation of pro-BNP with PRX, OSI, and PARylation was still present. Conclusions Markers of oxidative-nitrative stress, PARP activation, and AIF translocation in blood components showed correlation to reduced cardiac function and the clinical appearance of CHF. These results may reinforce the consideration of PARP inhibition as a potential therapeutic target in CHF.

Functional Relationship between Arterial Tissue and Perivascular Adipose Tissue in Metabolic Syndrome.

Metabolic syndrome is a complex of disorders that includes visceral obesity, insulin resistance, hypertension, and dyslipidemia. It is characterized by an increased risk for serious cardiovascular events. Adipocytes are now recognized to contribute to the development of cardiovascular complications in metabolic syndrome via the release of several bioactive substances (adipocytokines). Obesity induces an increase in the volume of perivascular adipose tissue (PVAT), which is located outside the blood vessels. In recent years, PVAT has been reported to produce/release vasoactive adipocytokines. Thus, PVAT can modulate vasomotor function by releasing vasorelaxing/vasocontracting factors, resulting in the development of cardiovascular disease due to metabolic syndrome. By using animal models (SHR/NDmcr-cp rats, SHRSP.Z-Lepr(fa)/IzmDmcr rats, and B6.BKS (D)-Lepr(fa)/J mice), we have demonstrated that chronic oxidative-nitrative stress is closely linked to the development of vascular dysfunction in response to nitric oxide (NO) in resistant arteries with increasing age/exposure to metabolic abnormalities. Further, our recent findings have led us to believe that PVAT helps in the regulation of vasodilation to compensate for the impaired vasodilation observed in pathophysiological conditions in the mesenteric arteries of SHRSP.Z-Lepr(fa)/IzmDmcr rats. However, a breakdown of the compensatory system occurs with long-term exposure to metabolic abnormalities. We propose the concept of the functional regulation of vascular tissue by PVAT in metabolic syndrome.

A gestatiós diabetes mellitus súlyossága befolyásolja a három évvel a szülést követően mért microvascularis diszfunkció mértékét, amely kapcsolatban állhat az emelkedett szisztémás oxidatív stresszel

Oxidative-nitrative stress and poly(ADP-ribose) polymerase activation observed in gestational diabetes may play role in the increased cardiovascular risk in later life. The present study aimed to examine the influence of the severity of previous gestational diabetes (insulin need) on vascular function three years after delivery. Furthermore, the authors investigated the relation of vascular function with oxidative-nitrative stress and poly(ADP-ribose) polymerase activation. Macrovascular function was measured by applanation tonometry; microvascular reactivity was assessed by provocation tests during Laser-Doppler flowmetry in 40 women who had gestational diabetes 3 years before the study. Oxidative-nitrative stress and poly(ADP-ribose) polymerase activity in blood components were determined by colorimetry and immunohistochemistry. Three years after insulin treated gestational diabetes impaired microvascular function and increased oxidative stress was observed compared to mild cases. The severity of previous gestational diabetes affects microvascular dysfunction that is accompanied by elevated oxidative stress. Nitrative stress and poly(ADP-ribose) polymerase activity correlates with certain vascular factors not related to the severity of the disease.

The Effect of Agaricus brasiliensis and Ganoderma lucidum Medicinal Mushroom Administration on the L-arginine/Nitric Oxide System and Rat Leukocyte Apoptosis in Experimental Type 1 Diabetes Mellitus.

Oxidative-nitrative stress develops as a result of hyperglycemia under diabetes mellitus. Formation of excessive reactive oxygen species and reactive nitrogen species leads to different cytotoxic effects and ultimately to increased cell death by apoptosis of immune-competent blood cells. This study showed the influence of medicinal mushroom (MM) administration on the L-arginine/nitric oxide (NO) system and rat leukocyte apoptosis under normal and experimental diabetic conditions. Animals were divided into 6 groups: (1) control, (2) control animals treated with Agaricus brasiliensis, (3) control animals treated with Ganoderma lucidum, (4) animals with experimental diabetes (EDM), (5) diabetic animals treated with A. brasiliensis, and (6) diabetic animals treated with G. lucidum. Control and diabetic animals were fed powdered mushrooms at a dose of 1 g/kg body weight. Administration of MMs to animals with diabetes caused a decrease in the activity of the NO synthase enzyme, as well as in the content of stable end products of NO metabolism-nitrates and nitrites-at the control level. The normalizing effect of mushrooms on the percentage of leukocytes that contain pro- (p53) and antiapoptotic (Bcl-2) proteins compared with the EDM group was shown by immunocytochemical analysis. Thus the administration of MMs under EDM showed a positive corrective action on the L-arginine/NO system and the ratio between p53 and Bcl-2 proteins in white blood cells, as well as on apoptotic index reduction.

Dioscin attenuates hepatic ischemia-reperfusion injury in rats through inhibition of oxidative-nitrative stress, inflammation and apoptosis.

Dioscin shows potent effects against liver damage in our previous studies; however, the action of it on hepatic ischemia-reperfusion (I/R) injury is still unknown. In the present article, the effects and possible mechanisms of dioscin against hepatic I/R injury were investigated. Seventy percent partial hepatic warm ischemia was induced in Wistar rats for 60 min followed by succedent reperfusion. In the prophylactic test, dioscin was administered intragastrically to the rats at doses of 20, 40, and 60 mg/kg once daily for seven consecutive days before I/R. In the therapeutic test, the rats received dioscin intragastrically at a dose of 60 mg/kg once 2 hr before I/R. We found that dioscin significantly decreased serum alanine aminotransferase and aspartate aminotransferase activities, increased survival rate of rats, and improved I/R-induced hepatocyte abnormality. In addition, dioscin obviously increased the levels of SOD, CAT, GSH-Px, GSH, decreased the levels of MDA, TNOS, iNOS, NO, and prevented DNA fragmentation caused by I/R injury. Further research indicated that dioscin markedly decreased the gene expressions of interleukin-1β, interleukin-6, tumor necrosis factor-α, intercellular adhesion molecule-1, MIP-1α, MIP-2, Fas, FasL, decreased the protein expressions of NF-κB, AP-1, COX-2, HMGB-1, CYP2E1, Bak, caspase-3, p53, PARP, Caspase-9, decreased the levels of JNK, ERK and p38 MAPKs phosphorylation, and upregulated the levels of Bcl-2 and Bcl-x. Our results suggest that dioscin has potent actions against hepatic I/R injury through suppression of inflammation, oxidative-nitrative stress, and apoptosis, which should be developed as a new drug to treat hepatic I/R injury in the future.

Abstract 604: Influence of Perivascular Adipose Tissue on Vasodilation in Metabolic Syndrome

Metabolic syndrome facilitates the development of cardiovascular disease due to atherosclerosis. We propose that chronic oxidative-nitrative stress is linked to the development of vascular dysfunction in response to nitric oxide (NO) in the coronary and mesenteric arteries of SHRSP.Z- Lepr fa /IzmDmcr (SHRSP.ZF) rats, an animal model of metabolic syndrome. Perivascular adipose tissue (PVAT), which is located outside blood vessels, has now been recognized as playing a role in vascular function. We assessed the role of PVAT in vascular dysfunction observed in SHRSP.ZF rats with metabolic syndrome. We used SHRSP.ZF rats at 13, 18, and 23 weeks, and observed obesity, hyperlipidemia, glucose intolerance, and hypertension from 13 weeks until 23 weeks of age. Relaxation induced by acetylcholine and sodium nitroprusside were unchanged in isolated mesenteric arteries of SHRSP.ZF rats at 13 weeks of age, but were impaired at 18 and 23 weeks of age compared to those in control Wistar-Kyoto rats (WKY). The relaxation induced by both agonists was greater in the mesenteric arteries enveloped by PVAT than in those without PVAT in SHRSP.ZF rats at 18 and 23 weeks of age. The relaxation in the arteries with PVAT in SHRSP.ZF rats were at similar levels as those in the arteries without PVAT in age-matched WKY. In contrast, no difference was observed in the relaxation levels in the arteries with and without PVAT in SHRSP.ZF rats at 13 weeks of age and in WKY at all ages. Histological analysis of PVAT showed that adipocytes in PVAT of SHRSP.ZF rats at 20 weeks of age were larger than those observed in WKY. Impaired NO-dependent vasodilation was also observed in aortas of SHRSP.ZF rats at 23 weeks of age compared to that in age-matched WKY, but the relaxation was not altered by the presence of PVAT. SHRSP.ZF rats with metabolic syndrome showed impairment in the NO-dependent pathway in resistant arteries, with increasing age/exposure to metabolic abnormalities. PVAT may help in the regulation of vasodilation to compensate for the impaired vasodilation observed under pathophysiological conditions, such as metabolic syndrome.

Brain edema in acute liver failure: mechanisms and concepts

Brain edema and associated increase in intracranial pressure continue to be lethal complications of acute liver failure (ALF). Abundant evidence suggests that the edema in ALF is largely cytotoxic brought about by swelling of astrocytes. Elevated blood and brain ammonia levels have been strongly implicated in the development of the brain edema. Additionally, inflammation and sepsis have been shown to contribute to the astrocyte swelling/brain edema in the setting of ALF. We posit that ammonia initiates a number of signaling events, including oxidative/nitrative stress (ONS), the mitochondrial permeability transition (mPT), activation of the transcription factor (NF-κB) and signaling kinases, all of which have been shown to contribute to the mechanism of astrocyte swelling. All of these factors also impact ion-transporters, including Na(+), K(+), Cl(-) cotransporter and the sulfonylurea receptor 1, as well as the water channel protein aquaporin-4 resulting in a perturbation of cellular ion and water homeostasis, ultimately resulting in astrocyte swelling/brain edema. All of these events are also potentiated by inflammation. This article reviews contemporary knowledge regarding mechanisms of astrocyte swelling/brain edema formation which hopefully will facilitate the identification of therapeutic targets capable of mitigating the brain edema associated with ALF.

Endoplasmic Reticulum Stress Plays a Key Role in the Pathogenesis of Diabetic Peripheral Neuropathy

Endoplasmic reticulum stress resulting from abnormal folding of newly synthesized proteins impairs metabolism, transcriptional regulation, and gene expression, and it is a key mechanism of cell injury. Endoplasmic reticulum stress plays an important role in cardiovascular and neurodegenerative diseases, cancer, and diabetes. We evaluated the role for this phenomenon in diabetic peripheral neuropathy. Endoplasmic reticulum stress manifest in upregulation of multiple components of unfolded protein response was identified in neural tissues (sciatic nerve, spinal cord) of streptozotocin diabetic rats and mice. A chemical chaperone, trimethylamine oxide, administered for 12 weeks after induction of diabetes (110 mg⋅kg−1⋅d−1, a prevention paradigm) attenuated endoplasmic reticulum stress, peripheral nerve dysfunction, intraepidermal nerve fiber loss, and sciatic nerve and spinal cord oxidative-nitrative stress in streptozotocin diabetic rats. Similar effects on diabetes-induced endoplasmic reticulum stress and peripheral nerve dysfunction were observed with a structurally unrelated chemical chaperone, 4-phenylbutyric acid (100 mg⋅kg−1⋅d−1, intraperitoneal). CCAAT/enhancer-binding protein homologous protein (CHOP)−/− mice made diabetic with streptozotocin displayed less severe sciatic nerve oxidative-nitrative stress and peripheral neuropathy than the wild-type (C57Bl6/J) mice. Neither chemical chaperones nor CHOP gene deficiency reduced diabetic hyperglycemia. Our findings reveal an important role of endoplasmic reticulum stress in the development of diabetic peripheral neuropathy and identify a potential new therapeutic target.