EVALUATION OF RED CURRANTS (RIBES RUBRUM L.), BLACK CURRANTS (RIBES NIGRUM L.), RED AND GREEN GOOSEBERRIES (RIBES UVA-CRISPA) FOR POTENTIAL MANAGEMENT OF TYPE 2 DIABETES AND HYPERTENSION USING IN VITRO MODELS

Red currants (Ribes rubrum L.), black currants (Ribes nigrum L.), red and green gooseberries (Ribes uva-crispa) were evaluated for the total phenolics, antioxidant capacity based on 2, 2-diphenyl-1-picrylhydrazyl radical scavenging assay and functionality such as in vitro inhibition of alpha-amylase, alpha-glucosidase and angiotensin I-converting enzyme (ACE) relevant for potential management of hyperglycemia and hypertension. The total phenolics content ranged from 3.2 (green gooseberries) to 13.5 (black currants) mg/g fruit fresh weight. No correlation was found between total phenolics and antioxidant activity. The major phenolic compounds were quercetin derivatives (black currants and green gooseberries) and chlorogenic acid (red currants and red gooseberries). Red currants had the highest alpha-glucosidase, alpha-amylase and ACE inhibitory activities. Therefore red currants could be good dietary sources with potential antidiabetes and antihypertension functionality to compliment overall dietary management of early stages of type 2 diabetes.

EFFECT OF THERMAL TREATMENT ON PHENOLIC COMPOUNDS AND FUNCTIONALITY LINKED TO TYPE 2 DIABETES AND HYPERTENSION MANAGEMENT OF PERUVIAN AND BRAZILIAN BEAN CULTIVARS (PHASEOLUS VULGARIS L.) USING IN VITRO METHODS

The effect of thermal treatment on phenolic compounds and type 2 diabetes functionality linked to alpha-glucosidase and alpha-amylase inhibition and hypertension relevant angiotensin I-converting enzyme (ACE) inhibition were investigated in selected bean (Phaseolus vulgaris L,) cultivars from Peru and Brazil using in vitro models. Thermal processing by autoclaving decreased the total phenolic content in all cultivars, whereas the 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity-linked antioxidant activity increased among Peruvian cultivars, alpha-Amylase and alpha-glucosidase inhibitory activities were reduced significantly after heat treatment (73-94% and 8-52%, respectively), whereas ACE inhibitory activity was enhanced (9-15%). Specific phenolic acids such as chlorogenic and caffeic acid increased moderately following thermal treatment (2-16% and 5-35%, respectively). No correlation was found between phenolic contents and functionality associated to antidiabetes and antihypertension potential, indicating that non phenolic compounds may be involved. Thermally processed bean cultivars are interesting sources of phenolic acids linked to high antioxidant activity and show potential for hypertension prevention.

Potential of Ginkgo biloba L. leaves in the management of hyperglycemia and hypertension using in vitro models

Leaves from four different Ginkgo biloba L. trees (1 and 2 - females; 3 and 4 - males), grown at the same conditions, were collected during a period of 5 months (from June to October, 2007). Water and 12% ethanol extracts were analyzed for total phenolics content, antioxidant activity, phenolic profile, and the potential in vitro inhibitory effects on alpha-amylase, alpha-glucosidase, and Angiotensin I-Converting Enzyme (ACE) enzymes related to the management of diabetes and hypertension. The results indicated a significant difference among the trees in all functional benefits evaluated in the leaf extracts and also found important seasonal variation related to the same functional parameters. In general, the aqueous extracts had higher total phenolic content than the ethanolic extracts. Also, no correlation was found between total phenolics and antioxidant activity. In relation to the ACE inhibition, only ethanolic extracts had inhibitory activity. (C) 2009 Elsevier Ltd. All rights reserved.

Protective effects of Mangifera indica L extract (Vimang), and its major component mangiferin, on iron-induced oxidative damage to rat serum and liver

In vivo preventive effects of a Mangifera indica L extract (Vimang) or its major component mangiferin on iron overload injury have been studied in rats given respectively, 50, 100, 250 mg kg(-1) body weight of Vimang, or 40 mg kg(-1) body weight of mangiferin, for 7 days prior to, and for 7 days following the administration of toxic amounts of iron-dextran. Both Vimang or mangiferin treatment prevented iron overload in serum as well as liver oxidative stress, decreased serum and liver lipid peroxidation, serum GPx activity, and increased serum and liver GSH, serum SOD and the animals overall antioxidant condition. Serum iron concentration was decreased although at higher doses, Vimang tended to increase it; percent tranferrin saturation, liver weight/body mass ratios, liver iron content was decreased. Treatment increased serum iron-binding capacity and decreased serum levels of aspartate-amine transferase (ASAT) and alanine-amine transferase (ALAT), as well as the number of abnormal Kupffer cells in iron-loaded livers. It is suggested that besides acting as antioxidants, Vimang extract or its mangiferin component decrease liver iron by increasing its excretion. Complementing earlier in vitro results from our group, it appears possible to support the hypothesis that Vimang and mangiferin present therapeutically useful effects in iron overload related diseases. (C) 2007 Elsevier Ltd. All rights reserved.

Antioxidant treatment reduces matrix metalloproteinase-2-induced vascular changes in renovascular hypertension

Mounting evidence indicates that structural and functional vascular changes associated with two-kidney, one-clip (2K-1C) hypertension result, at least in part, from altered activity of matrix metalloproteinases (MMPs). Because MMPs are upregulated by increased formation of reactive oxygen species (ROS), we hypothesized that antioxidant approaches could attenuate the increases in MMP-2 expression/activity and the vascular dysfunction and remodeling associated with 2K-1C hypertension. Sham-operated or 2K-1C hypertensive rats were treated with tempol 18 mg/kg/day or apocyanin 25 mg/kg/day (or vehicle). Systolic blood pressure was monitored weekly. After 8 weeks of treatment, aortic rings were isolated to assess endothelium-dependent and -independent relaxation. Quantitative morphometry of structural changes in the aortic wall was studied in hematoxylin/eosin sections. Aortic and systemic ROS levels were measured using dihydroethidine and thiobarbituric acid-reactive substances, respectively. Aortic MMP-2 levels and activity were determined by gelatin and in situ zymography, fluorimetry, and immunohistochemistry. Tempol and apocyanin attenuated 2K-1C hypertension (181 +/- 20.8 and 192 +/- 17.6 mm Hg, respectively, versus 213 +/- 18 mm Hg in hypertensive controls; both p<0.05) and prevented the reduction in endothelium-dependent vasorelaxation found in 2K-1C rats. Tempol, but not apocyanin (p>0.05), prevented the vascular remodeling found in 2K-1C rats (all p<0.01). Tempol was more effective than apocyanin in attenuating hypertension-induced increases in oxidative stress (both p<0.05), MMP-2 levels, and MMP-2 activity in hypertensive rats (all p<0.05). Our results suggest that antioxidant approaches decrease MMP-2 upregulation and attenuate the vascular dysfunction and remodeling during 2K-1C hypertension. (C) 2009 Elsevier Inc. All rights reserved.

Evidence of caspase-mediated apoptosis induced by L-amino acid oxidase isolated from Bothrops atrox snake venom

The aim of this work was to investigate the involvement of caspases in apoptosis induced by L-amino acid oxidase isolated from Bothrops atrox snake venom. The isolation of LAAO involved three chromatographic steps: molecular exclusion on a G-75 column; ion exchange column by HPLC and affinity chromatography on a Lentil Lectin column. SDS-PAGE was used to confirm the expected high purity level of BatroxLAA0. It is a glycoprotein with 12% sugar and an acidic character, as confirmed by its amino acid composition, rich in ""Asp and Glu"" residues. It displays high specificity toward hydrophobic L-amino acids. The N-terminal amino acid sequence and internal peptide sequences showed close structural homology to other snake venom LAAOs. This enzyme induces in vitro platelet aggregation, which may be due to H(2)O(2) production by LAAOs, since the addition of catalase completely inhibited the aggregation effect. It also showed cytotoxicity towards several cancer cell lines: HL60, Jurkat, B16F10 and PC12. The cytotoxicity activity was abolished by catalase. A fluorescence microscopy evaluation revealed a significant increase in the apoptotic index of these cells after BatroxLAAO treatment. This observation was confirmed by phosphatidyl serine exposure and activation of caspases. BatroxLAAO is a protein with various biological functions that can be involved in envenomation. Further investigations of its function will contribute to toxicology advances. Published by Elsevier Inc.

Cell cycle arrest evidence, parasiticidal and bactericidal properties induced by L-amino acid oxidase from Bothrops atrox snake venom

The present article describes an L-amino acid oxidase from Bothrops atrox snake venom as with antiprotozoal activities in Trypanosoma cruzi and in different species of Leishmania (Leishmania braziliensis, Leishmania donovani and Leishmania major). Leishmanicidal effects were inhibited by catalase, suggesting that they are mediated by H(2)O(2) production. Leishmania spp. cause a spectrum of diseases, ranging from self-healing ulcers to disseminated and often fatal infections, depending on the species involved and the host`s immune response. BatroxLAAO also displays bactericidal activity against both Gram-positive and Gram-negative bacteria. The apoptosis induced by BatroxLAAO on HL-60 cell lines and PBMC cells was determined by morphological cell evaluation using a mix of fluorescent dyes. As revealed by flow cytometry analysis, suppression of cell proliferation with BatroxLAAO was accompanied by the significant accumulation of cells in the G0/G1 phase boundary in HL-60 cells. BatroxLAAO at 25 mu g/mL and 50 mu g/mL blocked G0-G1 transition, resulting in G0/G1 phase cell cycle arrest, thereby delaying the progression of cells through S and G2/M phase in HL-60 cells. This was shown by an accentuated decrease in the proportion of cells in S phase, and the almost absence of G2/M phase cell population. BatroxLAAO is an interesting enzyme that provides a better understanding of the ophidian envenomation mechanism, and has biotechnological potential as a model for therapeutic agents. (C) 2011 Elsevier Masson SAS. All rights reserved.

Platelet protease-activated receptor 1 and membrane expression of P-selectin in pulmonary arterial hypertension

Introduction: Pulmonary arterial hypertension (PAH) is frequently associated with thrombotic events, particularly involving the pulmonary microcirculation at sites of vascular injury. We therefore decided to analyse protease-activated receptor 1 (PAR1), a key element in the activation of human platelets by thrombin, in PAH patients in stable clinical condition. Methods: Using flow cytometry, we analyzed platelet PAR1 density, PAR1-mediated exposure of P-selectin and the formation of platelet-leukocyte aggregates in 30 PAH patients aged 11 to 78 years (median 50.5 years). The control group consisted of 25 healthy subjects with the same age range as patients. Results: In patients, total platelet PAR1 density and uncleaved PAR1 density correlated negatively with platelet count (r(2) = 0.33 and r(2) = 0.34 respectively, p < 0.0015). In patients with a low platelet count (<150 x 10(9) platelets/L), both densities were increased relative to controls (82% and 33% respectively, p < 0.05). Thrombin peptide-induced platelet exposure of P-selectin was directly related to total and uncleaved PAR1 density (respectively, r(2) = 0.33 and r(2) = 0.29, p < 0.0025) and increased in subjects with low platelet count (46% versus those with normal platelet count, p < 0.05). Patients with low platelet count had decreased in vitro thrombin-induced formation of platelet-leukocyte aggregates (57% decrease versus controls, p < 0.05). Conclusions: There seems to be a subpopulation of PAH patients with increased propensity to thrombotic events as suggested by increased platelet PAR1 expression and PAR-mediated surface exposure of P-selectin associated with decreased platelet count. (C) 2009 Elsevier Ltd. All rights reserved.

Time course of haemodynamic, respiratory and inflammatory disturbances induced by experimental acute pulmonary polystyrene microembolism

Background and objective The time course of cardiopulmonary alterations after pulmonary embolism has not been clearly demonstrated and nor has the role of systemic inflammation on the pathogenesis of the disease. This study aimed to evaluate over 12 h the effects of pulmonary embolism caused by polystyrene microspheres on the haemodynamics, lung mechanics and gas exchange and on interleukin-6 production. Methods Ten large white pigs (weight 35-42 kg) had arterial and pulmonary catheters inserted and pulmonary embolism was induced in five pigs by injection of polystyrene microspheres (diameter similar to 300 mu mol l(-1)) until a value of pulmonary mean arterial pressure of twice the baseline was obtained. Five other animals received only saline. Haemodynamic and respiratory data and pressure-volume curves of the respiratory system were collected. A bronchoscopy was performed before and 12 h after embolism, when the animals were euthanized. Results The embolism group developed hypoxaemia that was not corrected with high oxygen fractions, as well as higher values of dead space, airway resistance and lower respiratory compliance levels. Acute haemodynamic alterations included pulmonary arterial hypertension with preserved systemic arterial pressure and cardiac index. These derangements persisted until the end of the experiments. The plasma interleukin-6 concentrations were similar in both groups; however, an increase in core temperature and a nonsignificant higher concentration of bronchoalveolar lavage proteins were found in the embolism group. Conclusion Acute pulmonary embolism induced by polystyrene microspheres in pigs produces a 12-h lasting hypoxaemia and a high dead space associated with high airway resistance and low compliance. There were no plasma systemic markers of inflammation, but a higher central temperature and a trend towards higher bronchoalveolar lavage proteins were found. Eur J Anaesthesiol 27:67-76 (C) 2010 European Society of Anaesthesiology.

Uridine adenosine tetraphosphate-induced contraction is increased in renal but not pulmonary arteries from DOCA-salt hypertensive rats

Matsumoto T, Tostes RC, Webb RC. Uridine adenosine tetraphosphate-induced contraction is increased in renal but not pulmonary arteries from DOCA-salt hypertensive rats. Am J Physiol Heart Circ Physiol 301: H409-H417, 2011. First published May 6, 2011; doi:10.1152/ajpheart.00084.2011.-Uridine adenosine tetraphosphate (Up(4)A) was reported as a novel endothelium-derived contracting factor. Up(4)A contains both purine and pyrimidine moieties, which activate purinergic (P2)X and P2Y receptors. However, alterations in the vasoconstrictor responses to Up(4)A in hypertensive states remain unclear. The present study examined the effects of Up(4)A on contraction of isolated renal arteries (RA) and pulmonary arteries (PA) from DOCA-salt rats using isometric tension recording. RA from DOCA-salt rats exhibited increased contraction to Up(4)A versus arteries from control uninephrectomized rats in the absence and presence of N(G)-nitro-L-arginine (nitric oxide synthase inhibitor). On the other hand, the Up(4)A-induced contraction in PA was similar between the two groups. Up(4)A-induced contraction was inhibited by suramin (nonselective P2 antagonist) but not by diinosine pentaphosphate pentasodium salt hydrate (Ip5I; P2X(1) antagonist) in RA from both groups. Furthermore, 2-thiouridine 5`-triphosphate tetrasodium salt (2-Thio-UTP; P2Y(2) agonist)-, uridine-5`-(gamma-thio)-triphosphate trisodium salt (UTP gamma S; P2Y(2)/P2Y(4) agonist)-, and 5-iodouridine-5`-O-diphosphate trisodium salt (MRS 2693; P2Y(6) agonist)-induced contractions were all increased in RA from DOCA-salt rats. Protein expression of P2Y(2)-, P2Y(4)-, and P2Y(6) receptors in RA was similar between the two groups. In DOCA-salt RA, the enhanced Up(4)A-induced contraction was reduced by PD98059, an ERK pathway inhibitor, and Up(4)Astimulated ERK activation was increased. These data are the first to indicate that Up(4)A-induced contraction is enhanced in RA from DOCA-salt rats. Enhanced P2Y receptor signaling and activation of the ERK pathway together represent a likely mechanism mediating the enhanced Up(4)A-induced contraction. Up(4)A might be of relevance in the pathophysiology of vascular tone regulation and renal dysfunction in arterial hypertension.

Nitrite or sildenafil, but not BAY 41-2272, blunt acute pulmonary embolism-induced increases in circulating matrix metalloproteinase-9 and oxidative stress

Introduction: Inhibition of matrix metalloproteinases (MMPs) improves the hemodynamics during acute pulmonary embolism (APE) and oxidative stress upregulates MMPs. We compared the effects of different NO-cGMP pathway activators on APE-induced increases in MMPs. Materials and Methods: Hemodynamic and biochemical evaluations were performed in non-embolized dogs treated with saline (N = 5), and in microspheres embolized dogs receiving saline (n = 9), or nitrite (6.75 mu mol/kg i.v. over 15 min followed by 0.28 mu mol/kg/min; n = 5), or sildenafil (0.25 mg/kg; n = 5), or BAY 41-2272 (0.03, 0.1, 0.3, and 1 mg/kg/h; n = 5). Plasma thiobarbituric acid reactive substances (TBARS) concentrations were determined. Zymograms of plasma samples were performed, and in vitro antioxidant effects or inhibition of MMPs by these drugs were examined. Results: APE increased mean pulmonary artery pressure by similar to 25 mmHg. Nitrite, BAY 41-2272, or sildenafil reversed this increase by similar to 40% (P < 0.05). Similar effects were seen on the pulmonary vascular resistance. While both nitrite and sildenafil produced no systemic effects, the highest dose of BAY 41-2272 produced systemic hypotension (P<0.05). While nitrite and sildenafil blunted the increases in plasma pro-MMP-9 levels and TBARS (all P < 0.05), BAY 41-2272 produced no such effects. Nitrite and sildenafll produced in vitro antioxidant effects and inhibited MMPs only at high concentrations. BAY 41-2272 produced no such effects. Conclusions: Activation of the NO-cGMP pathway with nitrite or sildenafil, but not with BAY 41-2272, attenuates APE-induced oxidative stress and increased MMP-9 levels. These findings are consistent with the idea that NO-cGMP pathway activators with antioxidant effects prevent the release of MMP-9 during APE. (c) 2008 Elsevier Ltd. All rights reserved.

Pyrrolidine dithiocarbamate down-regulates vascular matrix metalloproteinases and ameliorates vascular dysfunction and remodelling in renovascular hypertension

BACKGROUND AND PURPOSE Mounting evidence implicates matrix metalloproteinase (MMP) in the vascular dysfunction and remodelling associated with hypertension. We tested the hypothesis that treatment with pyrrolidine dithiocarbamate (PDTC), which interferes with NF-kappa B-induced MMPs gene transcription, could exert antihypertensive effects, prevent MMP-2 and MMP-9 up-regulation, and protect against the functional alterations and vascular remodelling of two-kidney, one clip (2K1C) hypertension. EXPERIMENTAL APPROACH Sham-operated or hypertensive rats were treated with vehicle or PDTC (100 mg.Kg(-1).day(-1)) by gavage for 8 weeks. Systolic blood pressure (SBP) was monitored weekly. Aortic rings were isolated to assess endothelium-dependent relaxations. Quantitative morphometry of structural alterations of the aortic wall was carried out in haematoxylin/eosin sections. Formation of vascular reactive oxygen species (ROS), and inducible (i) NOS and phosphorylated-p65 NF-kappa B subunit expression were measured in the aortas. MMP-2 and MMP-9 aortic levels and gelatinolytic activity were determined by gelatin and in situ zymography and by immunofluorescence. KEY RESULTS Treatment with PDTC attenuated the increases in SBP and prevented the endothelial dysfunction associated with 2K1C hypertension. Moreover, PDTC reversed the vascular aortic remodelling, the increases in aortic ROS levels and in iNOS and phosphorylated-p65 NF-kappa B expression found in 2K1C rats. These effects were associated with attenuation of 2K1C up-regulation of aortic MMP-2 and MMP-9 levels and gelatinolytic activity. CONCLUSION AND IMPLICATIONS These findings suggest that PDTC down-regulates vascular MMPs and ameliorates vascular dysfunction and remodelling in renovascular hypertension, thus providing evidence supporting the suggestion that PDTC is probably a good candidate to be used to treat hypertension.

Lifetime Overproduction of Circulating Angiotensin-(1-7) Attenuates Deoxycorticosterone Acetate-Salt Hypertension-Induced Cardiac Dysfunction and Remodeling

We evaluated the development of arterial hypertension, cardiac function, and collagen deposition, as well as the level of components of the renin-angiotensin system in the heart of transgenic rats that overexpress an angiotensin (Ang)-(1-7)-producing fusion protein, TGR(A1-7)3292 (TG), which induces a lifetime increase in circulating levels of this peptide. After 30 days of the induction of the deoxycorticosterone acetate (DOCA)-salt hypertension model, DOCA-TG rats were hypertensive but presented a lower systolic arterial pressure in comparison with DOCA-Sprague-Dawley (SD) rats. In contrast to DOCA-SD rats that presented left ventricle (LV) hypertrophy and diastolic dysfunction, DOCA-TG rats did not develop cardiac hypertrophy or changes in ventricular function. In addition, DOCA-TG rats showed attenuation in mRNA expression for collagen type I and III compared with the increased levels of DOCA-SD rats. Ang II plasma and LV levels were reduced in SD and TG hypertensive rats in comparison with normotensive animals. DOCA-TG rats presented a reduction in plasma Ang-(1-7) levels; however, there was a great increase in Ang-(1-7) (approximate to 3-fold) accompanied by a decrease in mRNA expression of both angiotensin-converting enzyme and angiotensin-converting enzyme 2 in the LV. The mRNA expression of Mas and Ang II type 1 receptors in the LV was not significantly changed in DOCA-SD or DOCA-TG rats. This study showed that TG rats with increased circulating levels of Ang-(1-7) are protected against cardiac dysfunction and fibrosis and also present an attenuated increase in blood pressure after DOCA-salt hypertension. In addition, DOCA-TG rats showed an important local increase in Ang-(1-7) levels in the LV, which might have contributed to the attenuation of cardiac dysfunction and prefibrotic lesions. (Hypertension. 2010;55:889-896.)

Central mechanisms involved in pilocarpine-induced pressor response

Pilocarpine (cholinergic muscarinic agonist) injected peripherally may act centrally to produce pressor responses; in the present study, using c-fos immunoreactive expression, we investigated the forebrain and brainstem areas activated by pressor doses of intravenous (i.v.) pilocarpine. In addition, the importance of vasopressin secretion and/or sympathetic activation and the effects of lesions in the anteroventral third ventricle (AV3V) region in awake rats were also investigated. In male Holtzman rats, pilocarpine (0.04 to 4 mu mol/kg b.w.) i.v. induced transitory hypotension followed by long lasting hypertension. Sympathetic blockade with prazosin (1 mg/kg b.w.) i.v. or AV3V lesions (1 day) almost abolished the pressor response to i. v. pilocarpine (2 mu mol/kg b.w.), whereas the vasopressin antagonist (10 mu g/kg b.w.) i.v. reduced the response to pilocarpine. Pilocarpine (2 and 4 mu mol/kg b.w.) i.v. increased the number of c-fos immunoreactive cells in the subfornical organ, paraventricular and supraoptic nuclei of the hypothalamus, organ vasculosum of the lamina terminalis, median preoptic nucleus, nucleus of the solitary tract and caudal and rostral ventrolateral medulla. These data suggest that i.v. pilocarpine activates specific forebrain and brainstem mechanisms increasing sympathetic activity and vasopressin secretion to induce pressor response. (C) 2011 Elsevier B.V. All rights reserved.

Evidence that L-glutamine is better than L-alanine as gluconeogenic substrate in perfused liver of weaned fasted rats submitted to short-term insulin-induced hypoglycaemia

Gluconeogenesis in livers from overnight fasted weaned rats submitted to short-term insulin-induced hypoglycaemia (IIH) was investigated. For this purpose, a condition of hyperinsulinemia/hypoglycaemia was obtained with an intraperitoneal (ip) injection of regular insulin (1.0 U kg(-1)). Control group (COG group) received ip saline. The studies were performed 30 min after insulin (IIH group) or saline (COG group) injection. The livers from IIH and COG rats were perfused with L-alanine (5 mM), L-lactate (2 mM)), L-glutamine (10 mM) or glycerol (2 mM). Hepatic glucose, L-lactate and pyruvate production from L-alanine was not affected by IIH. In agreement with this result, the hepatic ability in producing glucose from L-lactate or glycerol remained unchanged (IIH group vs. COG group). However, livers from IIH rats showed higher glucose production from L-glutamine than livers front COG rats and, in the IIH rats, the production of glucose from L-glutamine was higher than that front L-alanine. The higher glucose production in livers from the IIH group. when compared with the COG group was due to its entrance further on gluconeogenic pathway. Taken together. the results suggest that L-glutamine is better than L-alanine, as gluconeogenic substrate in livers of hypoglyceaemic weaned rats. Copyright (C) 2008 John Wiley & Sons. Ltd.