Resveratrol, a polyphenol found in wine, reduces ischemia reperfusion injury in rat kidneys

Protective effect of resveratrol against LPS-induced extracellular lipoperoxidation in AR42J cells partly via a Myd88-dependent signaling pathway

Lipopolysaccharides (LPS) are major components of the cell wall of Gram negative bacteria implicated in the pathogenesis of bacterial infection. Resveratrol is a polyphenolic phytoalexin exhibiting antioxidant and anti-inflammatory properties. We investigated the protective effects of this natural compound on LPS-induced proinflammatory effect using non-myeloid AR42J pancreatic cells. We found that LPS dose-dependently increased extracellular malondialdehyde (MDA) and nitric oxide without affecting their intracellular level whereas resveratrol abolished all these deleterious effects. LPS increased CD14 expression; IRAK1 and a phosphorylated form of p38 MAPK protein. Resveratrol counteracted LPS effect by decreasing CD14 and IRAK1 expression but unexpectedly increased the p38 MAPK protein phosphorylation. Altogether, our data highlighted the functionality of the TLR4-Myd88 signaling pathway in LPS pro-oxidant effect using non-myeloid cells. They further suggested that resveratrol exerted antioxidant properties either by a Myd88-dependent way not involving IRAK1 or by a TRIF dependent pathway.

Effect of resveratrol on tubular damage and interstitial fibrosis in kidneys of rats exposed to cigarette smoke

The aim of this study was to evaluate the effect of resveratrol on kidney tissue of rats exposed to cigarette smoke. Forty adult male Wistar Albino rats were divided into four groups. Animals in group 1 was the control group. For 6 weeks, group 2 was exposed to cigarette smoke; group 3 received daily intraperitoneal injections of resveratrol (10 mg/kg/d); and group 4 was exposed to both cigarette smoke and intraperitoneal resveratrol. All rats were sacrificed with cervical dislocation. The kidney tissues were obtained, fixed in Bouin's fixative and embeded in paraffin blocks. Samples were sectioned to 4-5 microns thickness, stained with hematoxylin/eosin (H/E), Masson's trichromic, periodic acid-schiff (PAS) and were examined by light microscopy for tubular injury and interstitial fibrosis. Results were compared by non-parametric tests. Hydropic degeneration, tubular atrophy, tubulo-interstitial fibrosis, interstitial cell infiltration, vacuolar degeneration and desquamation were prominent in group 2. In group 4, hydropic degeneration, epithelial cell vacuolization and desquamation was not observed, but occasional tubular atrophy and dilation were observed. Our study suggests that, some morphological alterations in the rat kidney, due to cigarette smoke may be prevented by resveratrol.

Resveratrol: a promising agent in promoting cardioprotection against coronary heart diseaseThis article is one of a selection of papers from the NATO Advanced Research Workshop on Translational Knowledge for Heart Health (published in part 2 of a 2-part Special Issue)

The inverse association between alcohol intake and coronary heart disease has been consistently reported in cross-culture, case–control, and cohort studies. Over the past couple of decades, however, many studies have explained promising health benefits associated with wine consumption. Some studies suggest that red wine is more cardioprotective than white wine, possibly due to the increased content of flavanoid antioxidants found in red wine. Several experimental studies, including ours, support the evidence that these beneficial effects are due to resveratrol, the polyphenolic compound present in red wine. Many studies have provided evidence that resveratrol possesses antioxidant and antiapoptotic effects apart from activation of longevity proteins (such as SIRT-1). We have recently reported the angiogenic, antihypercholesterolemic, and antidiabetic effects of resveratrol and the mechanisms involved in reduced ventricular remodeling and increased cardiac functions. We have also shown different strategic target molecules involved in resveratrol-mediated cardioprotection. Therefore, this review discusses the potential effect of resveratrol and the mechanisms involved in resveratrol-mediated cardioprotection during myocardial infarction, hypercholesterolemia, and diabetes rendering its beneficial effects during health and disease.

Downregulation of miR-199a derepresses hypoxia-inducible factor-1alpha and Sirtuin 1 and recapitulates hypoxia preconditioning in cardiac myocytes

MicroRNAs are posttranscriptional gene regulators that are differentially expressed during various diseases and have been implicated in the underlying pathogenesis. We report here that miR-199a is acutely downregulated in cardiac myocytes on a decline in oxygen tension. This reduction is required for the rapid upregulation of its target, hypoxia-inducible factor (Hif)-1alpha. Replenishing miR-199a during hypoxia inhibits Hif-1alpha expression and its stabilization of p53 and, thus, reduces apoptosis. On the other hand, knockdown of miR-199a during normoxia results in the upregulation of Hif-1alpha and Sirtuin (Sirt)1 and reproduces hypoxia preconditioning. Sirt1 is also a direct target of miR-199a and is responsible for downregulating prolyl hydroxylase 2, required for stabilization of Hif-1alpha. Thus, we conclude that miR-199a is a master regulator of a hypoxia-triggered pathway and can be exploited for preconditioning cells against hypoxic damage. In addition, the data demonstrate a functional link between 2 key molecules that regulate hypoxia preconditioning and longevity.

Protective effect of resveratrol on acute endotoxemia-induced nephrotoxicity in rat through nitric oxide independent mechanism

Lipopolysaccharide (LPS) is a glycolipid component of the cell wall of gram negative bacteria inducing deleterious effects on the kidney. Endotoxemia-induced nephrotoxicity is characterized by disturbed intracellular redox balance and reactive oxygen species (ROS) accumulation leading to DNA, proteins and membrane lipid damages. Resveratrol (trans-3,5,4'-trihydroxystilbene) is a polyphenol displaying antioxidant and anti-inflammatory properties. This study investigated its effects on LPS-induced nephrotoxicity in rats. Resveratrol counteracted all LPS-induced changes in renal haemodynamic parameters. In the kidney resveratrol abrogated LPS-induced lipoperoxidation and antioxidant enzyme activities depletion as superoxide dismutase (SOD) and catalase (CAT) but not peroxidase (POD) activity. LPS increased plasma and urine nitric oxide (NO) level and resveratrol reversed them. More importantly, LPS-induced iron mobilization from plasma to kidney, which was also abolished by resveratrol treatment. All these results suggest that resveratrol exerted strong antioxidant properties against LPS-induced nephrotoxicity and that its mode of action seemed to involve iron shuttling proteins.

Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases

BACKGROUND

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation.

REVIEW

We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation).The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible.This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron) molecules that are nominally antioxidants can actually act as pro-oxidants. The reduction of redox stress thus requires suitable levels of both antioxidants and effective iron chelators. Some polyphenolic antioxidants may serve both roles.Understanding the exact speciation and liganding of iron in all its states is thus crucial to separating its various pro- and anti-inflammatory activities. Redox stress, innate immunity and pro- (and some anti-)inflammatory cytokines are linked in particular via signalling pathways involving NF-kappaB and p38, with the oxidative roles of iron here seemingly involved upstream of the IkappaB kinase (IKK) reaction. In a number of cases it is possible to identify mechanisms by which ROSs and poorly liganded iron act synergistically and autocatalytically, leading to 'runaway' reactions that are hard to control unless one tackles multiple sites of action simultaneously. Some molecules such as statins and erythropoietin, not traditionally associated with anti-inflammatory activity, do indeed have 'pleiotropic' anti-inflammatory effects that may be of benefit here.

CONCLUSION

Overall we argue, by synthesising a widely dispersed literature, that the role of poorly liganded iron has been rather underappreciated in the past, and that in combination with peroxide and superoxide its activity underpins the behaviour of a great many physiological processes that degrade over time. Understanding these requires an integrative, systems-level approach that may lead to novel therapeutic targets.

Effect of melatonin, curcumin, quercetin, and resveratrol on acute ferric nitrilotriacetate (Fe-NTA)-induced renal oxidative damage in rats

The influence of melatonin, curcumin, quercetin, and resveratrol pretreatment on ferric nitrilotriacetate (Fe-NTA)-induced oxidative renal damage was studied. Male Wistar rats were treated orally once daily for 3 days with melatonin (10 mg/kg), curcumin (50 mg/kg), quercetin (15 mg/kg), and resveratrol (10 mg/kg). One hour after the last dose of antioxidants, a single dose of Fe-NTA was administered (8 mg of Fe/kg body weight, i.p.) to pre-treated animals. Twenty-four hours after Fe-NTA administration, the lipid peroxidation (LP), reduced glutathione (GSH), catalase (CAT), and glutathione peroxidase (GSH-Px) were estimated in kidney homogenates. Iron, zinc, and copper concentrations were estimated in kidney tissue. Administration of Fe-NTA to rats induced renal LP (170%, P < 0.001) and inhibited catalase (78%, P < 0.05) in the kidney. The oral pretreatment with melatonin, curcumin, quercetin, and resveratrol each one was effective in decreasing the Fe-NTA-induced LP (P < 0.001); however, it did not influence the FeNTA-induced inhibition of renal CAT activity. No changes were found in renal GSH level and GSH-Px activity compared to control animals. The pretreatment with antioxidants did not affect the increase in renal iron content, blood urea nitrogen/creatinine ratio, and relative kidney weight of FeNTA-intoxicated rats. The results indicate that the pretreatment with natural antioxidants, curcumin, melatonin, quercetin, and resveratrol, significantly and equally suppressed lipid peroxidation induced by Fe-NTA but had no effect on other markers of FeNTA nephrotoxicity and iron deposition in kidneys.

Protective effect of resveratrol in endotoxemia-induced acute phase response in rats

Lipopolysaccharide (LPS), a glycolipid component of the cell wall of gram-negative bacteria can elicit a systemic inflammatory process leading to septic shock and death. Acute phase response is characterized by fever, leucocytosis, thrombocytopenia, altered metabolic responses and redox balance by inducing excessive reactive oxygen species (ROS) generation. Resveratrol (trans-3,5,4' trihydroxystilbene) is a natural polyphenol exhibiting antioxidant and anti-inflammatory properties. We investigated the protective effect of resveratrol on endotoxemia-induced acute phase response in rats. When acutely administered by i.p. route, resveratrol (40 mg/kg b.w.) counteracted the effect of a single injection of LPS (4 mg/kg b.w.) which induced fever, a decrease in white blood cells (WBC) and platelets (PLT) counts. When i.p. administered during 7 days at 20 mg/kg per day (subacute treatment), resveratrol abrogated LPS-induced erythrocytes lipoperoxidation and catalase (CAT) activity depression to control levels. In the plasma compartment, LPS increased malondialdehyde (MDA) via nitric monoxide (NO) elevation and decreased iron level. All these deleterious LPS effects were reversed by a subacute resveratrol pre-treatment via a NO independent way. Resveratrol exhibited potent protective effect on LPS-induced acute phase response in rats.

High performance liquid chromatographic method for the determination and pharmacokinetic studies of oxyresveratrol and resveratrol in rat plasma after oral administration of Smilax china extract

A sensitive and simple HPLC method has been developed and validated for the determination of oxyresveratrol (trans-2,4,3',5'-tetrahydroxystilbene, OXY) and resveratrol (trans-3,5,4'-trihydroxystilbene, RES) in rat plasma. The plasma samples were extracted with ethyl acetate and analyzed using HPLC on an Aglient Zorbax SB-C(18) column (250 x 4.6 mm, 5 microm) at a wavelength 320 nm, with a linear gradient of (A) acetonitrile and (B) 0.5% aqueous acetic acid (v/v), at a flow rate of 1.0 mL/min. The method was linear over the range of 0.1265-25.3 microg/mL for OXY and 0.117-23.4 microg/mL for RES. The extraction recovery for OXY, RES and internal standard ranged from 71.1 to 88.3%. The intra- and inter-day precisions were better than 10%, and the accuracy ranged from 89 to 108%. The validated method was used to study the pharmacokinetic profiles of OXY and RES in rat plasma after oral administration of Smilax china root extract.

Bone marrow-derived cells mobilized by granulocyte-colony stimulating factor facilitate vascular regeneration in mouse kidney after ischemia/reperfusion injury

Bone marrow-derived cells (BMDC) play crucial roles in tissue regeneration. Granulocyte-colony stimulating factor (G-CSF) mobilizes BMDC and may facilitate the repair of kidney tissues after ischemia/reperfusion (I/R) injury. The tissue protective action of resveratrol, an antioxidant, might modify the regenerating potential of BMDC in I/R renal injury. This study examined whether G-CSF and/or resveratrol affect the recruitment of BMDC into vascular endothelial cells and renal tubular cells and the kidney function after I/R injury. I/R renal injury was induced in female mice that had been lethally irradiated and transplanted with male bone marrow cells. The mice were given saline, resveratrol or G-CSF, daily for 7 days. Non-irradiated and non-bone-marrow-transplanted female mice, which underwent the same kidney injury, were included as control. White blood cell (WBC) count and serum creatinine were monitored. Immunohistologic evaluation for renal tubular cells (cytokeratin) and endothelial cells (factor VIII-related antigen), and fluorescence in situ hybridization for mouse Y chromosome were performed. Although WBC was significantly higher in the G-CSF group, there was no significant difference in creatinine levels among all groups. Factor VIII-related antigen-positive cells with a Y-chromosome signal were identified in the capillary wall between renal tubuli and most frequently seen in the G-CSF group (p < 0.0001). Resveratrol did not affect kidney recovery in this model. No cytokeratin-positive renal tubular cells having a Y-chromosome signal were identified. In conclusion, BMDC are recruited into endothelial cell in I/R renal injury without apparent renal tubular cell regeneration, and G-CSF facilitates the endothelial cell regeneration.

Protection of rabbit kidney from ischemia/reperfusion injury by green tea polyphenol pretreatment

Reactive oxygen species (ROS) have been implicated in the pathogenesis of renal injury after ischemia/reperfusion (I/R). Recently, green tea polyphenols (GTP) have been found to protect the myocardium and liver against II/R injury. Less attention, however, has been paid to the protective effects of GTP with respect to the kidneys. This study was designed to determine whether GTP could protect renal cells from ischemic injury. The rabbits were divided into three groups of equal size: control (sham-operated), I/R + vehicle (normal saline) and I/R + GTP groups. Each group consisted of six rabbits. Animals underwent 30, 60, 90 and 120 min of ischemia, followed by 24 h of reperfusion, respectively. GTP (200 microg/kg) or the vehicle was administered 45 min prior to commencement of I/R. The results demonstrated that GTP administration resulted in a significant (P < 0.05) reduction of renal damage after 90 min of ischemia, as indicated by the decreased levels of creatinine and urea nitrogen in serum. These results were confirmed by histological examinations, which showed that GTP pretreatment inhibited necrosis and sloughing of the proximal tubules induced by I/R. Examinations also showed decreased necrotic areas in the medulla and decreased glomerular collapse in the I/R-injured rabbits. Moreover, the infiltration of CD8+ T cells was considerably decreased in GTP-treated kidneys. The results of this study suggest that GTP can reduce renal injury by preventing the oxidative stress dependent on I/R and may be used in renal transplantation as an antioxidant.

Resveratrol alleviates cardiac dysfunction in streptozotocin-induced diabetes: Role of nitric oxide, thioredoxin, and heme oxygenase

Excessive oxidative stress has been implicated in the pathology and complications of diabetes, which leads to myocardial ischemia reperfusion injury. The present study was designed to examine whether resveratrol (trans-3,5,4'-trihydroxystilbene), a polyphenolic compound present in red wine has a direct cardioprotective effect on diabetic myocardium. Resveratrol (2.5 mg/kg body wt/day) and L-NAME (25 mg/kg body wt/day) were administered orally for 15 days to streptozotocin (65 mg/kg)-induced diabetic rats. Sprague Dawley rats were divided into 5 groups: (i) control, (ii) diabetic, (iii) diabetic+resveratrol, (iv) diabetic+resveratrol+L-NAME (nitric oxide synthase inhibitor), and (v) diabetic+L-NAME. In our present study resveratrol demonstrated significant reduction in glucose level in diabetic rats. After the treatment, the hearts were excised and subjected to 30 min of global ischemia followed by 2 h of reperfusion. Resveratrol-treated diabetic rats demonstrated significant reduction in glucose levels as compared to the nontreated diabetic animals, and improved left ventricular function throughout reperfusion compared to the diabetic or L-NAME-treated animals (dp/dt(max) 1457+/-51 vs 999+/-44 mm Hg/s at 120 min reperfusion). Cardioprotection from ischemic injury in resveratrol-treated diabetic rats showed decreased infarct size (42% vs 51%) and cardiomyocyte apoptosis (35% vs 40%) as compared with diabetic animals. Resveratrol produced significant induction of p-AKT, p-eNOS, Trx-1, HO-1, and VEGF in addition to increased activation of MnSOD activity in diabetic animals compared to nondiabetic animals. However treatment with L-NAME in resveratrol-treated and nontreated diabetic animals demonstrated significant downregulation of the above-noted protein expression profile and MnSOD activity. In the present study we found that the mechanism(s) responsible for the cardioprotective effect of resveratrol in the diabetic myocardium include upregulation of Trx-1, NO/HO-1, and VEGF in addition to increased MnSOD activity and reduced blood glucose level. Thus this study shows a novel mechanism of pharmacological preconditioning with resveratrol in the diabetic myocardium.

Effects of resveratrol on glycerol-induced renal injury

Glycerol-induced renal lesions can have many causes, including increased oxidative stress and inflammation. Resveratrol, a polyphenolic phytoalexin found in grapes and red wine, is an antioxidant agent with anti-inflammatory effects. In the present study, we investigated the possible protective effect of resveratrol on glycerol-induced nephrotoxicity. Male Wistar rats were injected intramuscularly with 8 ml/kg of either 50% glycerol (n=18), glycerol+resveratrol (n=22), 0.15 M saline (n=14), saline+carboxymethylcellulose (n=10) or saline+resveratrol (n=8). The rats were killed 3 days after the injections, at which time the kidneys were removed for histological and immunohistochemical studies and lipid peroxidation determination. Blood and urine samples were collected in order to quantify sodium and creatinine. The results of the histological and immunohistochemical studies were scored according to the extent of damage and immunostaining, respectively, in the cortical tubulointerstitium. Lipid peroxidation was estimated by measuring malondialdehyde in renal tissue samples collected from control rats and glycerol-injected rats. By postinjection day 3, glycerol-only treated rats presented increases in plasma creatinine levels, as well as in fractional excretion of sodium and potassium (P<0.001). These increases were less pronounced in glycerol+resveratrol-treated rats (P<0.05). Cortical expression of macrophages, lymphocytes, nuclear factor-kappa B, heme oxygenase-1 and nitrotyrosine was greater in glycerol-treated rats than in controls (P<0.001). In addition, the histological findings for glycerol-treated rats were characteristic of acute tubular necrosis. Resveratrol attenuated all of these alterations (P<0.001). We conclude that resveratrol ameliorates glycerol-induced renal injury by suppressing the inflammatory process and by inhibiting lipid peroxidation.

Wine consumption and renal diseases: new perspectives

Investigations into the relation between wine consumption and kidney disease have been limited. Patients with chronic renal failure show accelerated atherosclerotic damage and, considering the well-known protective effect of wine on the cardiovascular system, moderate wine consumption might be advantageous. Oxidative stress and endothelial dysfunction, which are inter-related, play a role in the pathophysiology of many renal diseases, including acute and chronic renal failure. Ethanol and non-alcoholic wine components, especially polyphenols, influence oxidative balance and endothelial function. Although long-term alcohol abuse has been associated with many renal alterations in humans, in experimental studies wine polyphenols enhanced kidney antioxidant defenses, exerted protective effects against renal ischemia/reperfusion injury, and inhibited apoptosis of mesangial cells. Moreover, in diabetic patients the administration of moderate amounts of red wine and a polyphenol-enriched diet slowed the progression of diabetic nephropathy. Moreover, the unfavorable effect of ethanol on blood pressure control seems to be counterbalanced by polyphenol protective effects. There is convincing evidence of a beneficial effect of controlled wine consumption patients with renal disease, but controlled clinical trials are needed to confirm this hypothesis.

Resveratrol inhibits proliferation of cultured rat cardiac fibroblasts: correlated with NO-cGMP signaling pathway

Rhizoma polygoni cuspidate, used as a traditional Chinese herb, offered the therapeutic potential for cardiovascular diseases. Resveratrol, extracted from root of the rhizoma polygoni cuspidate has sparked increasing interest in therapeutic application. Resveratrol was shown to exert a variety of pharmacological effects including cardioprotective and cancer chemopreventive properties. However, its mechanisms of the action are not completely understood. The aim of this study was to investigate the molecular mechanism of resveratrol on preventing cardiac fibroblasts from proliferative and hypertrophic response induced by angiotensin II. Cell proliferation and cytotoxicity were detected by methyl thiazolyl tetrazolium (MTT) and lactate dehydrogenase (LDH) release assay, respectively. Hypertrophic response of cardiac fibroblasts was measured by mRNA expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). Resveratrol (25, 50, 75, and 100 microM) inhibited cardiac fibroblasts proliferation in a dose- and time-dependent manner compared with angiotensin II group (P<0.01), and the inhibitory effects were blocked by pretreatment with N(G)-nitro-l-arginine methyl ester (L-NAME) and 1H-[1,2,4]-oxadiazole-[4,3-a]-quinoxalin-1-one (ODQ). Resveratrol increased nitric oxide (NO) and nitric oxide synthase (NOS) levels in culture medium, increased intracellular cyclic GMP (cGMP) level in cardiac fibroblasts, and decreased ANP and BNP levels in culture medium. The mRNA expression of ANP and BNP was suppressed by resveratrol. These results suggested that resveratrol inhibited cardiac fibroblasts proliferation induced by angiotensin II, and the inhibitory effect might be associated with the activation of NO-cGMP signaling pathway.

Gentamicin-induced nephrotoxicity in rats ameliorated and healing effects of resveratrol

In this study, we aimed to investigate the possible protective effect of resveratrol on gentamicin induced nephrotoxicity. Experiments were carried out in male Wistar rats weighing 200-250 g. Gentamicin sulfate (80 mg/kg per day i.p.), resveratrol (10 mg/kg per day i.p.) and gentamicin together with resveratrol were administered for 6 d. The animals were sacrificed 24 h after the last injection. Urine, blood samples and tissue samples were collected from the animals on the seventh day of the treatment before they were sacrificed. Kidneys were collected for histopathological studies and fixed in 10% buffered formalin solution. Tissue samples were stored at -70 degrees C in liquid nitrogen for the determination of glutathione (GSH), glutathione-S-transferase (GST), malondialdehyde (MDA) and catalase (CAT). Glutathione assay was determined by the method of Beutler et al. GST amounts were measured by the method of Habig et al. Catalase activity was tested by Aebi's method and MDA was determined according to Thayer's method. Blood urea level was significantly increased in the gentamicin treated group. The study showed lowered levels of urea and creatinine levels in resveratrol administered groups when compared with gentamicin administered rats, and the difference was statistically significant. It has been determined that resveratrol caused statistically significant decrease in lipid peroxidation and reduced the level of catalase. Histopathological examination showed that resveratrol prevented partly gentamicin induced tubular damage. The results histopathologically demonstrated that resveratrol has a protective effect against gentamicin induced nephrotoxicity, lipid peroxidation and cellular damage in rats.

Cytotoxicity induced by grape seed proanthocyanidins: role of nitric oxide

Grape seed proanthocyanidin extract (GPSE) at high doses has been shown to exhibit cytotoxicity that is associated with increased apoptotic cell death. Nitric oxide (NO), being a regulator of apoptosis, can be increased in production by the administration of GSPE. In a chick cardiomyocyte study, we demonstrated that high-dose (500 microg/ml) GSPE produces a significantly high level of NO that contributes to increased apoptotic cell death detected by propidium iodide and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining. It is also associated with the depletion of intracellular glutathione (GSH), probably due to increased consumption by NO with the formation of S-nitrosoglutathione. Co-treatment with L-NAME, a NO synthase inhibitor, results in reduction of NO and apoptotic cell death. The decline in reduced GSH/oxidized GSH (GSSG) ratio is also reversed. N-Acetylcysteine, a thiol compound that reacts directly with NO, can reduce the increased NO generation and reverse the decreased GSH/GSSG ratio, thereby attenuating the cytotoxicity induced by high-dose GSPE. Taken together, these results suggest that endogenous NO synthase (NOS) activation and excessive NO production play a key role in the pathogenesis of high-dose GSPE-induced cytotoxicity.

Isohumulones Derived from Hops Ameliorate Renal Injury via an Anti-Oxidative Effect in Dahl Salt-Sensitive Rats

Previous studies have reported that isohumulones, the bitter compounds in beer, improve insulin resistance and hyperlipidemia in several animal models. In this study, we examined whether isohumulones ameliorate renal injury. Dahl salt-sensitive hypertensive rats were fed a low-salt diet (LS), a high-salt diet (HS) or a high-salt diet containing 0.3% isohumulones (HS+IH) for 4 weeks. Urinary nitrite/nitrate (NOx) excretion was measured at 4 weeks along with blood pressure and urinary protein excretion. Renal injury was evaluated histologically and reactive oxygen species (ROS) and nitric oxide (NO) production in the renal cortex was visualized. Oxidative stress and NO synthase (NOS) expression were evaluated by immunohistochemical staining and Western blot analysis. Mean blood pressure was significantly decreased in the HS+IH group compared with the HS group at 4 weeks (158.1+/-8.7 vs. 177.5+/-3.7 mmHg; p<0.05). Isohumulones prevented the development of proteinuria in the HS+IH group compared with the HS group at 2 weeks (61.7+/-26.8 vs. 117.2+/-9.8 mg/day; p<0.05). Glomerulosclerosis and interstitial fibrosis scores were significantly decreased in the HS+IH group compared with the HS group (0.61+/-0.11 vs. 1.55+/-0.23, 23.7+/-6.8 vs. 36.1+/-3.5%; p<0.05 for both). In the HS group, increased ROS and decreased NO were observed in glomeruli in vivo. Isohumulones reduced the ROS production, leading to the restoration of bioavailable NO. Urinary NOx excretion was significantly increased in the HS+IH group compared with the HS group. Furthermore, renal nitrotyrosine was increased in the HS group compared with the LS group, and this effect was prevented by isohumulones. Renal NOS expression did not differ among the three groups. These results suggest that isohumulones may prevent the progression of renal injury caused by hypertension via an anti-oxidative effect.

Antioxidants in the Prevention of Renal Disease

Reactive oxygen species (ROS) play a key role in the pathophysiological processes of renal diseases. The cellular damage is mediated by an alteration in the antioxidant status, which increases the concentration of ROS in the stationary state (oxidative stress). Oxidative stress mediates a wide range of renal impairments, from acute renal failure, rhabdomyolysis, obstructive nephropathy, hyperlipidemia, and glomerular damage to chronic renal failure and hemodialysis. Therefore, interventions favoring the scavenging and/or depuration of ROS (dietary and pharmacological antioxidants) should attenuate or prevent the oxidative stress, thereby mitigating against the subsequent renal damage.

Resveratrol Improves Ischemia/Reperfusion-Induced Oxidative Renal Injury in Rats

BACKGROUND

The present study was designed to examine whether resveratrol, a potent antioxidant, protects against renal ischemia-reperfusion (I/R) injury.

METHODS

Wistar albino rats were unilaterally nephrectomized and subjected to 45 min of renal pedicle occlusion followed by 6 h of reperfusion. Resveratrol (RVT, 30 mg/kg, i.p.) or vehicle was administered twice, at 30 min prior to ischemia and immediately before the reperfusion period. At the end of the reperfusion period, rats were decapitated and kidney samples were taken for histological examination or determination of levels of renal malondialdehyde (MDA), an end product of lipid peroxidation; glutathione (GSH), a key antioxidant; and myeloperoxidase (MPO) activity, an index of tissue neutrophil infiltration. Formation of reactive oxygen species in hepatic tissue samples was monitored by using chemiluminescence (CL) technique with luminol and lucigenin probes. Renal tissue collagen content as a fibrosis marker was also determined, while serum creatinine and urea concentrations were measured for the evaluation of renal function. Tumor necrosis factor-alpha (TNF-alpha ) and lactate dehydrogenase (LDH) were also assayed in serum samples.

RESULTS

Ischemia/reperfusion caused a significant decrease in tissue GSH level, which was accompanied by significant increases in the renal luminol and lucigenin CL values, MDA level, MPO activity and collagen content. Similarly, serum creatinine and BUN levels, as well as LDH and TNF-alpha, were elevated in the I/R group as compared to control group. On the other hand, resveratrol treatment reversed all these biochemical indices, as well as histopathological alterations that were induced by I/R.

CONCLUSIONS

Findings of the present study suggest that resveratrol exerts renoprotective effects via its radical scavenging and antioxidant activities, which appear to involve the inhibition of tissue neutrophil infiltration.

Cardioprotective effect of resvaratrol pretreatment on myocardial ischemia–reperfusion induced injury in rats

OBJECTIVE

The major objective of the present study was to examine the cardioprotective effect of resveratrol, an antioxidant presents in red wine, in the rat after ischemia-reperfusion (I/R).

DESIGN

The left coronary artery was in occlusion for 30 min followed by a 120 min reperfusion in anesthetized rats. Animals were pretreated with and without resveratrol before occlusion. The post-ischemic ventricular function (left ventricle maximum systolic pressures and the maximal first derivative of developed pressure) and myocardial infarct size and myocardial nitric oxide (NO) and malonaldehyde (MDA) content were compared.

RESULTS

Resveratrol pretreatment had dramatic cardioprotective effects on post-ischemic ventricular functional recovery and decreasing myocardial infarct size. Resveratrol pretreatment also increased NO and decreased MDA content in myocardium.

CONCLUSIONS

Resveratrol has cardioprotective properties in I/R rats. The cardioprotective effects in the I/R rats may be correlated with its antioxidant activity and upregulation of NO production.

Effect of resveratrol on nitrate tolerance in isolated human internal mammary artery

The present study aims to examine whether resveratrol, a natural antioxidant present in red wine, restores the tolerance to nitroglycerin (GTN) on isolated human internal mammary artery (IMA), using an in vitro model of nitrate tolerance. IMA rings were obtained from 53 male patients undergoing coronary bypass operation. Nitrate tolerance was induced by incubating the artery ring with 100 microM GTN for 90 minutes. Concentration-response curves to GTN (10(-9) to 10(-4) M) were obtained on IMA rings precontracted with noradrenaline. A low concentration (5 microM) of lucigenin was used as a tool to measure superoxide production in IMA segments. GTN produced concentration-dependent relaxation in isolated human IMA rings. Preexposure of artery rings to GTN reduced the relaxations to GTN [E(max) values: 105 +/- 2% and 76 +/- 3%, n = 10 to 12, P < 0.05; EC(50) values (-log M): 6.72 +/- 0.05 and 4.95 +/- 0.06, P < 0.05, respectively]. Relaxation to sodium nitroprusside remained unchanged. Diminished relaxation to GTN is partially restored after removing endothelium or L(G)-nitro-L-arginine (L-NOARG, 10 M) or superoxide dismutase (20 and 200 U/mL) or catalase (200 U/mL) pretreatments. Pretreatments with resveratrol (1, 10, and 20 microM) for 20 minutes relatively improved the reduced relaxation to GTN in tolerant IMA rings. Coadministration of L-NOARG with resveratrol did not abolish the beneficial effect of resveratrol on nitrate tolerance. The inhibitory effect of resveratrol on GTN-induced tolerance was not abolished in arterial rings without endothelium. Exposure to GTN increased superoxide production in IMA segments with endothelium. Endothelium denudation, L-NOARG, or superoxide dismutase pretreatments markedly inhibited the increased superoxide production in tolerant arteries. Resveratrol (1 and 10 microM) almost completely abolished basal or NAD(P)H-stimulated superoxide production in tolerant and nontolerant arteries. Vascular tolerance to GTN, in in vitro tolerant human IMA rings, can be induced by endothelial superoxide anions. Resveratrol partially restored the reduced relaxation to GTN by inhibiting NAD(P)-derived superoxide production in endothelium.

Protective effect of resveratrol, a polyphenolic phytoalexin on glycerol-induced acute renal failure in rat kidney

Rhabdomyolysis-induced myoglobinuric acute renal failure (ARF) accounts for about 10% to 40% of all cases of ARF. Reactive oxygen intermediates have been demonstrated to play an etiologic role in myoglobinuric renal failure. This study was designed to investigate the effect of resveratrol, a polyphenolic phytoalexin in glycerol-induced ARF in rats. Seven groups of rats were employed in this study, group I served as control; group II was given 50% glycerol (8 mL/kg, intramuscularly); groups III IV, and V were given glycerol plus resveratrol (2 mg/kg, 5 mg/kg, and 10 mg/kg p.o. route, respectively) 60 min prior to the glycerol injection; group VI received L-NAME (10 mg/kg, i.p.) along with glycerol and resveratrol (5 mg/kg), group VII animals received L-NAME (10 mg/kg) 30 min prior to glycerol administration. Renal injury was assessed by measuring plasma creatinine, blood urea nitrogen, creatinine, and urea clearance. The oxidative stress was measured by renal malondialdehyde levels and reduced glutathione levels, and by enzymatic activity of catalase, glutathione reductase, and superoxide dismutase. Tissue and urine nitrite levels were measured as an index of total nitric oxide levels. Glycero treatment resulted in a marked decrease in tissue and urine nitric oxide levels, renal oxidative stress, and significantly deranged the renal functions along with deterioration of renal morphology. Pre treatment of animals with resveratrol (5 and 10 mg/kg) 60 min prior to glycerol injection markedly attenuated the fall in nitric oxide levels, renal dysfunction, morphologic alterations, reduced elevated thiobarbituric acid reacting substances, and restored the depleted renal antioxidant enzymes. This protection afforded by resveratrol was significantly reversed by cotreatment of L-NAME along with resveratrol, clearly indicating that resveratrol exerts its protective effect through nitric oxide release along with the antioxidative effect in glycerol-induced ARF.

Therapeutic potential of resveratrol: the in vivo evidence

Resveratrol, a constituent of red wine, has long been suspected to have cardioprotective effects. Interest in this compound has been renewed in recent years, first from its identification as a chemopreventive agent for skin cancer, and subsequently from reports that it activates sirtuin deacetylases and extends the lifespans of lower organisms. Despite scepticism concerning its bioavailability, a growing body of in vivo evidence indicates that resveratrol has protective effects in rodent models of stress and disease. Here, we provide a comprehensive and critical review of the in vivo data on resveratrol, and consider its potential as a therapeutic for humans.

Protective effect of nitric oxide pathway in resveratrol renal ischemia-reperfusion injury in rats

BACKGROUND

Nitric oxide (NO), synthesized from L-arginine by the enzyme nitric oxide synthase (NOS), seems to play an ambiguous role during tissue ischemia-reperfusion (I/R) injury. This study was designed to investigate the effects of resveratrol, a polyphenolic phytoalexin, in renal ischemia reperfusion (RIR) injury in rats.

METHODS

Forty-eight rats were randomized into six groups. Group 1: sham operated (C); group 2: right nephrectomy (UNI); group 3: UNI + 45 min of ischemia and 24 h of reperfusion in the contralateral kidney; group 4: UNI + RIR + L-NAME (10 mg/kg, i.p.); group 5: UNI + RIR + resveratrol (5 mg/kg, p.o.); group 6: UNI + RIR + resveratrol + L-NAME. At the end of the reperfusion period, rats were sacrificed. Thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) levels, catalase (CAT), and superoxide dismutase (SOD) activities were determined in renal tissue. Serum creatinine and blood urea nitrogen (BUN) were measured for the evaluation of renal function. Tissue and urine nitrite levels were measured to assess total nitric oxide levels.

RESULTS

Ischemic control animals demonstrated severe deterioration of renal function, altered renal morphology, reduced total nitric oxide levels and a marked renal oxidative stress.

CONCLUSIONS

Pretreatment of animals with resveratrol markedly attenuated renal dysfunction, morphological alterations, improved nitric oxide levels, reduced elevated TBARS levels and restored the depleted renal antioxidant enzymes, However, treatment with L-NAME attenuated this protection afforded by resveratrol indicating that resveratrol exerts its protective effect through NO release.

Resveratrol prevents CsA inhibition of proliferation and osteoblastic differentiation of mouse bone marrow-derived mesenchymal stem cells through an ER/NO/cGMP pathway

The purpose of this study was to investigate the in vitro effects of resveratrol (RSVL) and cyclosporin A (CsA) on proliferation and osteoblastic differentiation of mouse bone marrow-derived mesenchymal stem cell (BMSC) cultures. Application of RSVL (10(-8) -10(-6) mol l(-1)) resulted in a dose-dependent increase in [3H]-thymidine incorporation, alkaline phosphatase (ALP) activity and calcium deposition of BMSCs cultures, which was accompanied with the increase of NO production and cGMP content. Concurrent treatment with the estrogen receptor antagonist ICI182,780 (10(-7) mol l(-1)) or the NO synthase inhibitor, Nomega-nitro-L-arginine methyl ester (6 x 10(-3) mol l(-1)) abolished the RSVL (10(-6) mol l(-1))-induced increase in NO production and cGMP content and eliminated the RSVL-induced increase in proliferation and osteoblastic differentiation of BMSCs. In contrast, CsA (10(-6) -10(-5) mol l(-1)) dose-dependently decreased [3H]-thymidine incorporation, ALP activity and calcium deposition of BMSCs cultures, which was accompanied with the reduction of NO production in the conditioned media. Concurrent treatment with RSVL (10(-6) mol l(-1)) significantly reversed the CsA (3 x 10(-6) mol l(-1))-mediated decrease in NO production and restored the proliferation and differentiation potential of BMSCs. Our data suggest that (1) the NO/cGMP pathway may play an important role in both RSVL-induced and CsA-inhibited proliferation and osteoblastic differentiation of mouse BMSCs, and (2) RSVL may act through an ER/NO/cGMP pathway to reverse the inhibitory effect of CsA on BMSC cultures. Taken together, the data suggest that RSVL may prevent osteoporosis induced by CsA.

Oxidative stress and protective effects of polyphenols: comparative studies in human and rodent kidney. A review

Reactive oxygen species (ROS) play a key role in the pathophysiological processes of a wide range of renal diseases. Thus, antioxidants are expected to decrease the vulnerability of the kidney to oxidative challenges. Polyphenols, particularly abundant in red wine, could act as ROS scavengers, iron chelators and enzyme modulators. In addition, chronic exposure to moderate amounts of ethanol results in increased activity of the renal antioxidant enzymes, further supporting a renoprotective effect of red wine based on its antioxidant properties. An enhancement of plasma antioxidant capacity following red wine consumption has been reported both in man and rodents, thereby providing a contributory factor to its renoprotective effect because the kidney is a highly perfused organ. Although phenol concentration of red wine does not influence the activity of antioxidant enzymes of the kidney, the concentration of these compounds is negatively correlated with tissue lipid peroxidation, assessed by thiobarbituric acid reactive substances, and positively correlated with the antioxidant capacity of plasma. Moreover, amelioration of myoglobinuric renal damage was found in rats following chronic exposure to flavonol-rich red wine. Also, pretreatment with resveratrol, or other red wine polyphenols, decreased kidney damage caused by ischaemia-reperfusion. The aim of the present review is to examine the pathophysiological basis of the renoprotective effect of red wine in man and rodents, based on functional, biochemical and ultrastructural evidence.

Protein oxidation and lipid peroxidation after renal ischemia-reperfusion injury: protective effects of erdosteine and N-acetylcysteine

Oxygen radicals have roles in the renal ischemia-reperfusion (IR) injury usually encountered in several conditions such as renal transplantation. The aim of this study was to investigate the effects of erdosteine and N-acetylcysteine (NAC) on the oxidant/antioxidant status and microscopy of renal tissues after IR injury. Male Sprague-Dawley rats were randomly assigned to four groups: control untreated rats, IR (30 min ischemia and 120 min reperfusion), IR + NAC (i.p.; 180 mg/kg) and IR + erdosteine (oral; 50 mg/kg/day for 2 days before experiments) groups. After unilateral renal IR, the right kidney was rapidly excised and sectioned vertically into two pieces for microscopic examination and biochemical analysis. Erdosteine and NAC treatment did not cause any significant change in the activity of superoxide dismutase (SOD) in comparison with the IR group, even if the SOD activity increased in IR groups than in the control group. Catalase (CAT) activity was decreased in the IR group in comparison with control and IR + erdosteine groups (P<0.05), whereas it was higher in the IR + erdosteine group than in the IR + NAC group (P<0.05). Xanthine oxidase (XO) activity was higher in all the IR-performed groups than in the control group (P<0.05). Thiobarbituric acid-reactive substances (TBARS) level and protein carbonyl (PC) content were increased after IR injury (P<0.05). Erdosteine or NAC treatments ameliorated these increased TBARS and PC contents in comparison with the IR group (P<0.05). Light microscopy of the IR group showed tubular dilatation, tubular necrosis and vacuole formation in epithelial cells. Erdosteine but not NAC apparently reduced the renal tissue damage. The pathological damage score after IR was significantly reduced after erdosteine treatment (P<0.05), but not after NAC treatment. In conclusion, renal IR resulted in oxidative damage as seen in biochemical lipid peroxidation and protein oxidation results with aggravated tubular necrosis. Erdosteine and NAC treatments improved the biochemical results of IR injury. However, on microscopic evaluations, animals receiving erdosteine showed a great reduction in renal damage when compared with the NAC group.

Role of nitric oxide in resveratrol-induced renal protective effects of ischemic preconditioning

BACKGROUND

Resveratrol, a natural antioxidant and polyphenol found in red wine and grapes, has been found to pharmacologically precondition the heart through upregulation of nitric oxide (NO). This study was designed to explore the involvement of NO in the renoprotective effect of resveratrol in renal ischemic preconditioning in rat kidney.

METHODS

Ischemic preconditioning was induced by three cycles 2-minutes of ischemia followed by 5 minutes of reperfusion before 45 minutes of prolonged ischemia. Resveratrol was given 1 hour before the surgical procedures.

RESULTS

Ischemic preconditioning and resveratrol treatment significantly improved the renal dysfunction, decrease in total NO levels, and oxidative stress induced by 45 minutes of ischemia followed by 24 hours of reperfusion. Histopatholgic examination of the kidneys of ischemic/reperfusion rats revealed severe renal damage, which was attenuated in both preconditioned and resveratrol-treated animals. Preconditioning and resveratrol administration led to a marked increase in NO levels in kidney. Renoprotective effects of resveratrol were abolished when animals were pretreated with NG-nitro-L-arginine methyl ester, a nonspecific NO synthase inhibitor.

CONCLUSIONS

These findings demonstrate an important contributory role of NO in the protection afforded by resveratrol in renal ischemic preconditioning.

CLINICAL RELEVANCE

It is now well established that brief periods of ischemia followed by reperfusion render a variety of tissues tolerant to subsequent ischemia/reperfusion-induced injury. This phenomenon, referred to as ischemic preconditioning, was first demonstrated in the dog myocardium. The potential for clinical application of such a powerful protective phenomenon has generated enormous interest in identifying the underlying intracellular signaling pathways, with the ultimate aim of pharmacologically exploiting these mechanisms to develop therapeutic strategies that can enhance tolerance to ischemia/reperfusion injury in patients. This study explored the possible involvement of nitric oxide in renal ischemic preconditioning.

Resveratrol, a natural red wine polyphenol, reduces ischemia-reperfusion-induced spinal cord injury

BACKGROUND

Severe neurologic injury still represents one of the most devastating complications after surgical repair of thoracoabdominal aneurysms. We therefore aimed to investigate the protective effect of resveratrol, a natural polyphenol antioxidant present in grapes and wine, in an experimental model of spinal cord ischemia-reperfusion injury.

METHODS

Sixteen rabbits were assigned either to group A (n = 8; receiving resveratrol, treated group) or group B (n = 8; control group, nontreated group) and underwent a 30-minutes period of spinal cord ischemia by clamping the abdominal aorta between the left renal artery and the aortic bifurcation. Fifteen minutes before clamping, rabbits received either intravenous resveratrol (100 microg/kg; group A) or normal saline (group B). Functional assessment with Tarlov score at 8, 16, and 24 hours postoperatively, histopathologic assessment of the spinal cord, measurements of malondialdehyde levels, and myeloperoxidase activity in the spinal cord were performed.

RESULTS

Neurologic impairment (Tavlov score for group A = 4.38 +/- 1.19 and for group B = 0.38 +/- 0.74, p < 0.001), malondialdehyde levels (47.71 +/- 7.81 nmol/g versus 86.56 +/- 11.39 nmol/g, p < 0.001), and myeloperoxidase activity (2.13 +/- 0.72 nm/min versus 3.75 +/- 0.78 nm/min, p = 0.002) were significantly lower in the resveratrol-treated animals. Additionally, pathologically assessed outcomes were better in the resveratrol-treated group. The total number of motor neurons in the gray matter was significantly lower in the nontreated group than in the resveratrol-treated group (14.26 +/- 2.94 versus 29.12 +/- 3.64, p = 0.003).

CONCLUSIONS

Prophylactic use of resveratrol reduced neurologic injury and provided clinical improvement by attenuating the inflammatory milieu in the rabbit spinal cord ischemia/reperfusion model.

Resveratrol protects against cold ischemia-warm reoxygenation-induced damages to mitochondria and cells in rat liver

Ischemia-reperfusion is a critical event in the development of primary graft dysfunctions after liver transplantations. Ischemia-reperfusion causes cell injuries which are related to the successive cold preservation-warm reperfusion (CPWR) periods required by the graft. Recent evidences suggest that oxidative stress plays an important role in the development of these injuries and that mitochondrial dysfunctions are involved. The purpose of this study was to investigate the effect of the natural phytoalexin resveratrol on the prevention of liver injuries induced by 40-h cold preservation followed by a warm reperfusion. CPWR induced liver mitochondrial and cellular damages as attested by the increase in lipid peroxidation of liver membranes, the alteration of oxidative phosphorylation parameters, mitochondrial swelling and the activation of the cellular markers of necrosis and apoptosis, i.e., lactate dehydrogenase (LDH) leakage, mitochondrial cytochrome c release and caspase activation. Resveratrol inhibits lipid peroxidation and protects mitochondrial functions. It improves respiratory chain activity and prevents opening of the permeability transition pore, allowing better recovery of ATP energetic charge. Resveratrol also limits the activation of the cellular markers of necrosis and apoptosis. These protective effects could be related to the antioxidant properties of the drug but also to its membrane-stabilizing activity. Indeed, further experiments demonstrate that resveratrol is able to prevent the release of cytochrome c caused by oxygen deprivation in isolated liver mitochondria. These data demonstrate that resveratrol ameliorates the liver injury induced by CPWR and appears as a promising drug to improve the primary function of the grafted liver after transplantation.

Possible role of nitric oxide in the protective effect of resveratrol in 5/6th nephrectomized rats

BACKGROUND

Nitric oxide (NO) plays an important role in the modulation of glomerular disease. The renal protective effect of resveratrol (RVT), a polyphenolic phytoalexin, was investigated in the 5/6th nephrectomized rats.

MATERIALS AND METHODS

Resveratrol (5 mg/kg, PO) was administered for 12 weeks to 5/6th nephrectomized (NX) rats together with and without nitro L-arginine methyl ester (L-NAME) (10 mg/kg, IP). We evaluated the effect of these agents on proteinuria, hypertension, renal function, glomerulosclerosis, and urinary excretion of nitric oxide metabolites.

RESULTS

5/6th NX resulted in elevation in systolic blood pressure (SBP), reduced the urinary excretion of NO metabolites, increased urinary protein excretion, and deranged renal function and glomerulosclerosis. Treatment of animals with resveratrol significantly attenuated the increase in SBP, preserved the normal renal function, reduced the urinary protein excretion, increased the urinary excretion of NO metabolites, and prevented the glomerulosclerosis. Co-administration of animals with L-NAME along with resveratrol prevented the protection observed with resveratrol.

CONCLUSION

These findings indicate that resveratrol exerts its protective effect in 5/6 NX rats through a nitric oxide pathway.

Resveratrol inhibits gentamicin-induced mesangial cell contraction

Gentamicin is an aminoglycoside antibiotic that is very effective in treating different gram negative infections, however, one of its main side effects is nephrotoxicity. Gentamicin-induced decreases in glomerular filtration rate could be mediated by mesangial cell contraction. Resveratrol, a natural hydroxystilbene, has been identified to be a potent antioxidant with many biological activities including protection against kidney diseases. As we have previously demonstrated that gentamicin induced a reduction of planar surface area of cultured rat mesangial cells, and that resveratrol has a protective effect on gentamicin-induced nephrotoxicity in vivo, the aim of this study was to investigate the effect of resveratrol on gentamicin-induced mesangial cell contraction. This study demonstrates that the contractile effect of gentamicin on mesangial cells can be prevented by incubation with resveratrol at an optimal dose of 10 microM, as it blunted the gentamicin-induced reduction in planar cell surface area and the number of contracted cells. Besides, the preincubation with 10(-5)M diphenylene iodinium (DPI), an inhibitor of the NADP(H) oxidase, also blunted gentamicin-induced cell contraction. This preventive effect was higher when cells were incubated with both substances together. These results strongly suggest that the protective effect resveratrol against gentamicin-induced reduction in renal function in vivo could be mediated by inhibiting gentamicin-induced mesangial cells contraction.

Coordinated induction of iNOS-VEGF-KDR-eNOS after resveratrol consumption: a potential mechanism for resveratrol preconditioning of the heart

Existing evidence indicates that resveratrol, a red wine and grape-derived polyphenolic antioxidant, can pharmacologically precondition the heart in a nitric oxide (NO)-dependent manner. To further explore the role of NO in resveratrol-mediated cardioprotection, the induction for the expression of the potential molecular targets of NO including VEGF and KDR as well as iNOS and eNOS were examined by Western blot analysis and immunohistochemistry. Two groups of rats were studied, one group of animals was fed resveratrol for 7 days while the other group was given water only. After 1, 3, 5 and 7 days, the rats were sacrificed and the expression of the proteins was examined by Western blot analysis. Western blot detected an overexpression of iNOS and VEGF within 24 h of resveratrol treatment while the induction of KDR was not increased until after 3 days and eNOS expression after 5 days of resveratrol treatment. These expressions were further increased after 7 days of resveratrol treatment, when the rats were sacrificed for the isolated working heart preparation. Resveratrol provided cardioprotection as evidenced by superior post-ischemic ventricular recovery, reduced myocardial infarct size and decreased number of apoptotic cardiomyocytes. Immunohistochemistry was performed in the hearts at baseline, and at the end of 30-min ischemia/2-h reperfusion. The hearts obtained from resveratrol-treated rats revealed enhanced expression for iNOS, eNOS and VEGF and KDR compared to control hearts at the end of reperfusion. The results of this study demonstrate that resveratrol leads to a coordinated upregulation of iNOS-VEGF-KDR-eNOS, which is likely to play a role in resveratrol-mediated cardioprotection.

Differential inhibition of oxidized LDL-induced apoptosis in human endothelial cells treated with different flavonoids

High plasma level of cholesterol is a well-known risk factor for atherosclerotic diseases. Oxidized LDL induces cellular and nuclear damage that leads to apoptotic cell death. We tested the hypothesis that flavonoids may function as antioxidants with regard to LDL incubated with 5 microm-Cu(2+) alone or in combination with human umbilical vein endothelial cells (HUVEC). Cytotoxicity and formation of thiobarbituric acid-reactive substances induced by Cu(2+)-oxidized LDL were examined in the presence of various subtypes of flavonoid. Flavanols, flavonols and flavanones at a non-toxic dose of 50 microm markedly inhibited LDL oxidation by inhibiting the formation of peroxidative products. In contrast, the flavones luteolin and apigenin had no such effect, with >30 % of cells killed after exposure to 0.1 mg LDL/ml. Protective flavonoids, especially (-)-epigallocatechin gallate, quercetin, rutin and hesperetin, inhibited HUVEC nuclear condensation and fragmentation induced by Cu(2+)-oxidized LDL. In addition, immunochemical staining and Western blot analysis revealed that anti-apoptotic Bcl-2 expression was enhanced following treatment with these protective flavonoids. However, Bax expression and caspase-3 cleavage stimulated by 18 h incubation with oxidized LDL were reduced following treatment with these protective flavonoids. The down-regulation of Bcl-2 and up-regulation of caspase-3 activation were reversed by the cytoprotective flavonoids, (-)-epigallocatechin gallate, quercetin and hesperetin, at >/=10 microm. These results suggest that flavonoids may differentially prevent Cu(2+)-oxidized LDL-induced apoptosis and promote cell survival as potent antioxidants. Survival potentials of certain flavonoids against cytotoxic oxidized LDL appeared to stem from their disparate chemical structure. Furthermore, dietary flavonoids may have therapeutic potential for protecting the endothelium from oxidative stress and oxidized LDL-triggered atherogenesis.

Resveratrol-mediated activation of cAMP response element-binding protein through adenosine A3 receptor by Akt-dependent and -independent pathways

A recent study documented a role of adenosine A(3)-Akt-cAMP response element-binding protein (CREB) survival signaling in resveratrol preconditioning of the heart. In this study, we demonstrate that resveratrol-mediated CREB activation can also occur through an Akt-independent pathway. Isolated rat hearts were perfused for 15 min with Krebs-Henseleit bicarbonate (KHB) buffer containing resveratrol in the absence or presence of adenosine A(3) receptor blocker MRS-1191 [3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(+/-)-dihydropyridine-3,5-dicar-boxylate], phosphatidylinositol 3 (PI3)-kinase inhibitor LY294002 [2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride], mitogen-activated extracellular signal-regulated protein kinase inhibitor PD098059 [2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one], or a combination of LY294002 and PD098059. All hearts were subsequently subjected to 30-min ischemia followed by 2-h reperfusion. Cardioprotection was examined by determining infarct size, cardiomyocyte apoptosis, and ventricular recovery. Resveratrol phosphorylated both Akt and CREB that was blocked by MRS-1191, which also abolished cardioprotective abilities of resveratrol. LY294002 completely inhibited Akt phosphorylation but partially blocked the phosphorylation of CREB. Inhibition of PI3-kinase also partially blocked resveratrol's ability to precondition the heart. PD098059 partially blocked the phosphorylation of CREB and resveratrol-mediated cardioprotection. Preperfusing the hearts with LY294002 and PD098059 together completely abolished the phosphorylation of CREB, simultaneously inhibiting resveratrol-mediated cardioprotection. The results indicate that resveratrol preconditions the hearts through adenosine A(3) receptor signaling that triggers the phosphorylation of CREB through both Akt-dependent and -independent pathways, leading to cardioprotection.

Effects of a phenolic compound, resveratrol, on the renal function and costimulatory adhesion molecule CD86 expression in rat kidneys with ischemia/reperfusion injury

Recent studies have suggested that an ischemia/reperfusion (I/R) injury enhances the expression of costimulatory adhesion molecules on the vascular endothelium. In the present study, we investigated the protective effects of resveratrol, a phenolic product, on the renal function and expression of CD86 in rat kidneys with I/R injury. Wistar rats were divided into four groups; 1) an I/R group with right nephrectomy and 1-hour clamping of the left renal pedicle; 2) a vehicle group, I/R plus 10% ethanol (0.1 ml/kg/day) administered by intra-peritoneal injection from day -1 through to 7; 3) a resveratrol group, I/R plus 4 mg/kg/day of resveratrol; and 4) a sham group. Blood samples were obtained via the tail vein at 1 day before, and 1, 3, and 7 days after the operation (day 0) for the measurement of serum creatinine (Scr) levels. The expression of CD86 protein was analyzed by immunofluorescence staining, and the level of CD86 messenger RNA (mRNA) was evaluated quantitatively by a real-time reverse transcription-polymerase chain reaction (RT-PCR) in the renal cortex at day 3. Scr levels of the resveratrol group were significantly lower than those of the I/R and vehicle groups on days 1 and 3 after the operation. From the immunohistochemical study, the expression of CD86 in the glomerular endothelium and peritubular vessels was found to be attenuated in the resveratrol group compared with the I/R or vehicle group. In the resveratrol group, the CD86 mRNA level was significantly lower than that in the I/R or vehicle group, and it was significantly decreased by about one fifth of that in the sham group. Our results suggest that resveratrol markedly reduces renal dysfunction and attenuates the mRNA and protein expression of CD86 following I/R injury.

Survival rates of patients with malignant melanoma of the skin

This paper reports on cases of malignant melanoma of the skin diagnosed in Finland between 1963 and 1968. Sufficient data for estimating the survival was obtained in 691 cases. The ten-year relative survival rate for the entire series was 41% for males and 53% for females. This sex difference remained constant throughout the various divisions of the material. The ten-year relative survival rate of males with tumour in stage I was 52% and that of females 59%. The highest survival rate of stage I tumour in males was for the tumours of the lower extremities (77%) and in females for those in the head and neck (79%). The relative survival of patients with tumour of the trunk in stage I was lowest in both sexes (males 49%, females 45%). The ten-year relative survival rate of patients with a local recurrence was 33% in males and 27% in females. The relative ten-year survival rates of patients with superficial melanoma were 130% in males and 92% in females.

Provinol prevents CsA-induced nephrotoxicity by reducing reactive oxygen species, iNOS, and NF-kB expression

Cyclosporine A (CsA) use is associated with several side effects, the most important of which is nephrotoxicity that includes, as we previously showed, tubular injury and interstitial fibrosis. Recently, many researchers have been interested in minimizing these effects by pharmacological interventions. To do this, we tested whether the administration of a red wine polyphenol, Provinol (PV), prevents the development of CsA-induced nephrotoxicity. Rats were treated for 21 days and divided into four groups: control; group treated with PV (40 mg/kg/day by oral administration in tap water); group treated with CsA (15 mg/kg/day by subcutaneous injection); group treated with CsA plus PV. CsA produced a significant increase of systolic blood pressure; it did not affect urinary output, but caused a significant decrease in creatinine clearance. These side effects were associated with an increase in conjugated dienes, which are lipid peroxidation products, inducible NO-synthase (iNOS), and nuclear factor (NF)-kB, which are involved in antioxidant damage. However, PV prevented these negative effects through a protective mechanism that involved reduction of both oxidative stress and increased iNOS and NF-kB expression induced by CsA. These results provide a pharmacological basis for the beneficial effects of plant-derived polyphenols against CsA-induced renal damage associated with CsA.

Resveratrol, a polyphenolic phytoalexin protects against cyclosporine-induced nephrotoxicity through nitric oxide dependent mechanism

Cyclosporine A (CsA) is a potent and effective immunosuppressive agent, but its use is frequently accompanied by severe renal toxicity. The causes for the nephrotoxicity of CsA have not been fully elucidated. Intrarenal vasoconstriction induced by several different mediators, both in humans and experimental animals have been proposed. The present study was designed to investigate the possible protective effect of resveratrol on CsA-induced nephrotoxicity and to explore the possible mechanism involved in resveratrol's effect. Eight groups of rats were employed in this study, group 1 served as control, group 2 rats were treated with olive oil (vehicle for CsA), group 3 rats were treated with CsA (20 mg/kg, s.c. for 21 days), groups 4, 5 and 6 received CsA along with resveratrol (2, 5 and 10 mg/kg, p.o. 24 h before and 21 days concurrently), respectively, group 7 rats were treated with NOS inhibitor, L-NAME (10 mg/kg) along with resveratrol and CsA and group 8 rats received L-NAME along with CsA. CsA administration for 21 days resulted in a marked renal oxidative stress, significantly deranged the renal functions, reduced the tissue and urine nitrite levels and markedly altered the renal morphology. Treatment with resveratrol (5 and 10 mg/kg) significantly improved the renal dysfunction; tissue and urine total nitric oxide levels, renal oxidative stress and prevented the alterations in renal morphology. Concurrent administration of L-NAME blocked the protective effect of resveratrol indicating that resveratrol exerts its protective effect by releasing nitric oxide. These results clearly demonstrate the pivotal role of nitric oxide in etiology of CsA nephrotoxicity and indicate the renoprotective potential of resveratrol in CsA nephrotoxicity.

Effect of resveratrol on microcirculation disorder and lung injury following severe acute pancreatitis in rats

AIM

To investigate the mechanism of resveratrol underlying the microcirculation disorder and lung injury following severe acute pancreatitis (SAP).

METHODS

Twenty-four rats were divided into 3 groups (SAP, sham and resveratrol groups) randomly. SAP model was established by injecting 4% sodium taurocholate 1 mL/kg through puncturing pancreatic ducts. Sham (control) group (8 rats) was established by turning over the duodenum. Resveratrol was given at 0.1 mg/kg b.m. intraperitoneally. Rats were sacrificed 9 h after SAP was induced. Blood samples were obtained for hemorrheological examination. Lung tissues were used for pathological observation, and examination of microvascular permeability, dry/wet ratio and myeloperoxidase (MPO) activity. Gene expression of intercellular adhesion molecule-1 (ICAM-1) was detected by RT-PCR.

RESULTS

Compared with SAP group, resveratrol relieved the edema and infiltration of leukocytes in the lungs. Resveratrol improved markers of hemorrheology: high VTB (5.77+/-1.18 mPas vs 9.49+/-1.34 mPas), low VTB (16.12+/-3.20 mPas vs 30.91+/-7.28 mPas), PV (4.69+/-1.68 mPas vs 8.00+/-1.34 mPas), BSR (1.25+/-0.42 mm/h vs 0.03+/-0.03 mm/h), VPC (54.67+/-3.08% vs 62.17+/-3.39%), fibrinogen (203.2+/-87.8 g/ L vs 51.3+/-19.1 g/L), original hemolysis (0.45+/-0.02 vs 0.49+/-0.02), and complete hemolysis (0.41+/-0.02 vs 0.43+/-0.02) (P<0.05). Resveratrol decreased the OD ratio of ICAM-1 gene (0.800+/-0.03 vs 1.188+/-0.10), dry/wet ratio (0.74+/-0.02 vs 0.77+/-0.03), microvascular permeability (0.079+/-0.006 vs 0.112+/-0.004) and MPO activity (4.42+/-0.32 vs 5.03+/-0.51) significantly (P<0.05).

CONCLUSION

Resveratrol can improve the microcirculation disorder of the lung by decreasing leukocyte-endothelial interaction, reducing blood viscosity, improving the decrease of blood flow, and stabilizing erythrocytes in SAP rats. It may be a potential candidate to treat SAP and its severe complications (ALI).

Effect of polyphenolic compounds on the renal Na+,K(+)-ATPase during development and persistence of hypertension in rats

It has been suggested that polyphenolic substances provide protection against the risk factors of cardiovascular diseases. The present study was designed to investigate whether application of red wine polyphenols influences the kinetic properties of the renal Na+,K(+)-ATPase in rats with hypertension (164 +/- 8 mmHg) that was experimentally induced by the NO synthase inhibitor N(G.) -nitro-L- arginine methyl ester (L-NAME). Polyphenols in a dose of 40 mg kg(-1) day(-1) in drinking fluid induced different effects on the properties of the renal Na+,K(+)-ATPase depending on the mode of their administration. Preventive application of polyphenols during the development of hypertension (144 +/- 5 mmHg) partially protected the Na+,K(+)-ATPase molecule against hypertension-induced deterioration via increased capability of the enzyme to bind ATP and/or Na+ as suggested by decrease of Km and KNa, respectively, even to values lower than in controls. However, polyphenols did not prevent the hypertension-induced reduction of the number of active Na+,K(+)-ATPase molecules as shown by similar V(max) values as compared to the hypertensive L-NAME group. The above protection is probably secured by a NO-dependent mechanism as suggested by 150% increase of the NO synthesis. Additional treatment of already hypertensive animals with polyphenols (153 +/- 8 mmHg) resulted in partial restoration of the Na+,K(+)-ATPase affinities especially for sodium as indicated by significant diminution of KNa. However, polyphenols in this mode of application did not slow down the L-NAME-induced decrease in the number of Na+,K(+)-ATPase molecules in the kidney as suggested by additional significant decrease in V(max) values when comparing this group with the control group and also the hypertensive L-NAME group. In this case the polyphenols affected the Na,K-ATPase molecule in a NO-independent way as indicated by the fact that polyphenols failed to restore normal NO synthesis.

Pharmacological preconditioning with resveratrol: role of CREB-dependent Bcl-2 signaling via adenosine A3 receptor activation

Recent studies demonstrated that resveratrol, a grape-derived polyphenolic phytoalexin, provides pharmacological preconditioning (PC) of the heart through a NO-dependent mechanism. Because adenosine receptors play a role in PC, we examined whether they play any role in resveratrol PC. Rats were randomly assigned to groups perfused for 15 min with 1) Krebs-Henseleit bicarbonate buffer (KHB) only; 2) KHB containing 10 microM resveratrol; 3) 10 microM resveratrol + 1 microM 8-cyclopentyl-1,3-dimethylxanthine (CPT; adenosine A(1) receptor blocker); 4) 10 microM resveratrol + 1 microM 8-(3-chlorostyryl)caffeine (CSC; adenosine A(2a) receptor blocker); 5) 10 microM resveratrol + 1 microM 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(+/-)-dihydropyridine-3,5-dicarboxylate (MRS-1191; adenosine A(3) receptor blocker); or 6) 10 microM resveratrol + 3 microM 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride [LY-294002, phosphatidylinositol (PI)3-kinase inhibitor], and groups perfused with adenosine receptor blockers alone. Hearts were then subjected to 30-min ischemia followed by 2-h reperfusion. The results demonstrated significant cardioprotection with resveratrol evidenced by improved ventricular recovery and reduced infarct size and cardiomyocyte apoptosis. CPT and MRS 1191, but not CSC, abrogated the cardioprotective abilities of resveratrol, suggesting a role of adenosine A(1) and A(3) receptors in resveratrol PC. Resveratrol induced expression of Bcl-2 and caused its phosphorylation along with phosphorylation of cAMP response element-binding protein (CREB), Akt, and Bad. CPT blocked phosphorylation of Akt and Bad without affecting CREB, whereas MRS 1191 blocked phosphorylation of all compounds, including CREB. LY-294002 partially blocked the cardioprotective abilities of resveratrol. The results indicate that resveratrol preconditions the heart through activation of adenosine A(1) and A(3) receptors, the former transmitting a survival signal through PI3-kinase-Akt-Bcl-2 signaling pathway and the latter protecting the heart through a CREB-dependent Bcl-2 pathway in addition to an Akt-Bcl-2 pathway.