Açaí Reverses Adverse Cardiovascular Remodeling in Renovascular Hypertension: A Comparative Effect With Enalapril.

ABSTRACT: This study aimed to determine if açai seed extract (ASE) could reverse pre-existing cardiovascular and renal injury in an experimental model of renovascular hypertension (2 kidney, 1 clip, 2K1C). Young male rats (Wistar) were used to obtain 2K1C and sham groups. Animals received the vehicle, ASE (200 mg/kg/d), or enalapril (30 mg/kg/d) in drinking water from the third to sixth week after surgery. We evaluated systolic blood pressure by tail plethysmography, vascular reactivity in the rat isolated mesenteric arterial bed (MAB), serum and urinary parameters, plasma inflammatory cytokines by ELISA, MAB expression of endothelial nitric oxide synthase and its active form peNOS by Western blot, plasma and MAB oxidative damage and antioxidant activity by spectrophotometry, and vascular and cardiac structural changes by histological analysis. ASE and enalapril reduced the systolic blood pressure, restored the endothelial and renal functions, and decreased the inflammatory cytokines and the oxidative stress in 2K1C rats. Furthermore, both treatments reduced vascular and cardiac remodeling. ASE substantially reduced cardiovascular remodeling and recovered endothelial dysfunction in 2K1C rats probably through its antihypertensive, antioxidant, and anti-inflammatory actions, supplying a natural resource for the treatment of renovascular hypertension.

Can the indicators of chronic ethanol consumption be minimized by a continuous flaxseed intake?

The aim of this study was to evaluate the use of flaxseed in animals subjected to ethanol-induced hepatotoxicity. Twenty-four male rats were divided into four groups (n = 6): control group (CG) which received a control diet and water ad libitum; flaxseed group (FG) which received control diet with an addition of 25% flaxseed flour and water ad libitum; ethanol control group (ECG) which received control diet and a solution of 10% ethanol (v/v) as the only liquid source; and ethanol flaxseed group (EFG) which received control diet with an addition of 25% flaxseed flour and a solution of 10% ethanol (v/v) as the only liquid source. The animals were euthanized at 60 days, when blood was collected for biochemical analysis and liver was collected for histomorphometric analysis. Rats fed with diets containing flaxseed showed lower values of alkaline phosphatase (P = 0.020) and lower concentration of total bilirubin (P = 0.006), direct bilirubin (P = 0.013) and indirect bilirubin (P = 0.018) compared to ECG and EFG. The groups receiving flaxseed diets demonstrated higher expression of superoxide dismutase (SOD) enzyme (P < 0.001) than CG and ECG but did not affect thiobarbituric acid (TBARS) expression (P = 0.055). Regarding liver analysis, the ECG and EFG showed larger hepatocyte nuclei and paler cytoplasm than the groups who had not received ethanol, and less in fluid accumulation (oedema) in the cytoplasm than was seen in the FG and EFG livers. These latter two groups showed fewer fatty cells than was seen in the groups that had not been given flaxseed, so that the diagnosis of hepatic steatosis was not justified. In conclusion, therefore, this study showed that the indicators of ethanol chronic consumption can be reduced by the introduction of continuous flaxseed dietary intake.

Euterpe oleracea Mart. (Açai) seed extract improves physical performance in old rats by restoring vascular function and oxidative status and activating mitochondrial muscle biogenesis.

OBJECTIVES: Alterations in cardiovascular and skeletal muscle function are hallmarks of ageing that lead to exercise intolerance. We aimed to examine whether the treatment with Euterpe oleracea Mart. seed extract (ASE) associated with exercise training improves aerobic exercise performance by promoting healthy ageing in the elderly. METHODS: Male Wistar rats were divided into five groups: Young (3 months), Old (18 months), Old+ASE (ASE 200 mg/kg/day), Old+Training (exercise training 30 min/day; 5 days/week) and Old+Training+ASE, for 4 weeks. KEY FINDINGS: ASE treatment increased the exercise time and the running distance concerning the initial maximal treadmill stress test (MTST) in the Old+Training+ASE group. Exercise training or ASE treatment restored the aorta oxidative damage and antioxidant defence. It reduced the acetylcholine (ACh)-induced vasodilation in the aorta of old animals to the same values as the young and improved hypertension. Only the association of both strategies restored the ACh-induced vasodilation in mesentery arteries. Remarkably, exercise training associated with ASE increased the antioxidant defence, nitrite levels and expression of the mitochondrial SIRT-1, PGC1α in soleus muscle homogenates. CONCLUSIONS: ASE treatment associated with exercise training contributes to better exercise performance and tolerance in ageing by improving vascular function, oxidative stress and activating the muscle SIRT-1/PGC-1α pathway.

Polyphenol-rich açaí seed extract exhibits reno-protective and anti-fibrotic activities in renal tubular cells and mice with kidney failure.

The main goal of this study was to evaluate the reno-protective effects of a phenolic-rich Açaí seed extract (ASE) in mice with kidney failure. Kidney failure was induced chemically with an adenine-rich diet (0.25% w/w for 4 weeks) in male CD1 Swiss mice. Mice were then provided daily with ASE (at a dose of ~ 350 mg/kg/day) in drinking water for 4 weeks. Adenine mice exhibited renal dysfunction evidenced by increased proteinuria, increased uremia, extensive tubular atrophy and kidney fibrosis associated with overexpression of pro-fibrotic genes (collagen 1a1, transforming growth factor ß1, TGF-ß1) and markers of tubular injury (such as Kidney injury molecule-1, KIM-1). ASE was able to beneficially counteract all these effects. ASE improved oxidative damage and fibrosis by decreasing carbonylated protein and MDA concentrations, as well as collagen deposition in renal tissue. ASE decreased the expression of TGF-ß1 gene and the abundance of protein TGF-ß1 in kidneys. It further decreased both expression and urinary excretion of tubular injury biomarkers, e.g., KIM-1 and Neutrophil gelatinase-associated lipocalin. CKD ASE-treated mice exhibited higher polyphenol content and total antioxidant capacity compared to control mice. ASE further prevented the expression of profibrotic genes in HK2 human tubular cells exposed to uremic toxins. Taken together, these findings suggest that ASE exerted potent reno-protective and anti-fibrotic effects through its antioxidant activity and the modulation of the TGF-ß1 pathway.

Role of the NO-cGMP pathway in the systemic antinociceptive effect of clonidine in rats and mice.

The mechanism underlying the analgesic effect of clonidine, an alpha(2)-adrenoceptor agonist, remains uncertain. Activation of alpha(2)-adrenoceptor induces the release of nitric oxide (NO) from endothelial cells, which has led us to test the hypothesis that the observed antinociceptive effect induced by the systemic administration of clonidine depends on the NO-cGMP pathway. The possible involvement of an opioid link in the antinociceptive effect of clonidine was also evaluated. The antinociceptive effect induced by systemic administration (intravenous or intraperitoneal) of clonidine was evaluated using the rat paw formalin, mice tail-flick and writhing tests. Clonidine (3-120 microg/kg) induces a dose-dependent antinociceptive effect in the formalin, tail-flick and writhing tests. The antinociceptive effect of clonidine in a dose that had no sedative effect assessed by rota rod test, was significantly reduced by NO-synthase and guanylyl cyclase inhibition. The antinociceptive effect of morphine, but not clonidine, was inhibited by naloxone. Our current results suggest that the antinociceptive effect of systemic clonidine does not involve the opioid receptor and is modulated by the NO-cGMP pathway.

Role of renin-angiotensin system and oxidative status on the maternal cardiovascular regulation in spontaneously hypertensive rats.

BACKGROUND: The purpose of this study was to investigate the contribution of renin-angiotensin system (RAS) and oxidative status on the maternal cardiovascular regulation at the end of pregnancy in normotensive and spontaneously hypertensive rats (SHR). METHODS: Blood pressure (BP), mesenteric arterial bed (MAB) reactivity, mesenteric oxidative damage, protein expression, and antioxidant activities were compared between four groups: SHR (SHR-P) and normotensive Wistar controls (W-P) in the 20th day of pregnancy or age-matched nonpregnant rats (SHR-NP and W-NP). RESULTS: BP in W-P and SHR-P was reduced at the end of pregnancy. The vasodilator effects of angiotensin II (Ang II) and angiotensin 1-7 (Ang-(1-7)) were higher in SHR-P than in other groups. Endothelial nitric oxide synthase (eNOS) expression was increased in W-P and SHR-P compared to nonpregnant groups. Angiotensin-converting enzyme (ACE) and AT(1) receptor expressions were increased in SHR-NP compared to normotensive groups and pregnancy reduced their expressions in SHR. No difference was observed in AT(2) receptor expression among the groups. ACE2 expression was higher in hypertensive than normotensive groups. The levels of thiobarbituric acid-reactive substances (TBARS) were reduced in pregnant compared to nonpregnant groups. Superoxide dismutase (SOD) activity was reduced in SHR-P compared to SHR-NP. However, pregnancy increased catalase (CAT) and glutathione peroxidase (GPx) activities in normotensive rats and SHR, respectively. CONCLUSIONS: The results suggest that the reduction of BP to normal values at the end of pregnancy in SHR may be related to an increased NO production and vasorelaxation to Ang II and Ang-(1-7) associated with decreased expression of vascular ACE and AT(1) receptors and oxidative status.

Mechanism of the endothelium-dependent vasodilator effect of an alcohol-free extract obtained from a vinifera grape skin.

An alcohol-free grape-skin extract (GSE) obtained from skins of Vitis labrusca has significant anti-hypertensive, antioxidant and vasodilator effects. According to our previous results, the vasodilator effect of GSE in the isolated mesenteric vascular bed (MVB) of the rat is dependent on endothelium and partially dependent on nitric oxide (NO). In the MVB of the rat pre-contracted with norepinephrine (NE), bolus injections of GSE induced a long-lasting dose-dependent vasodilation that is significantly reduced after the treatment with 1H-[1,2,3] oxadiazolo [4,4-a] quinoxalin-1-one (ODQ). Additionally, in vessels pre-contracted with norepinephrine and depolarized with KCl (25 mM) or treated with Ca(2+)-dependent K(+)-channel blockers charybdotoxin (ChTx) plus apamin, the vasodilator effect of GSE was significantly reduced and almost abolished by ChTx plus apamin plus L-NAME. However, the vasodilator effect of GSE was unaffected by D-Arg[Hyp(3),Thi(5),D-Tic(7),Oic(8)]bradykinin (HOE-140), atropine, yohimbine, pyrilamine and 4-aminopyridine (4-AP). The vasoconstriction response elicited by bolus injection of KCl was not affected by GSE, whereas the vasoconstrictor response induced by NE was dose-dependently and completed inhibited by GSE in the presence but not in the absence of endothelium. However, NE-induced vasoconstriction in calcium-free condition or without endothelium was not reduced by GSE. The present results demonstrate that GSE induces a vasodilator effect in the rat MVB, which is dependent on NO in combination with endothelium-derived hyperpolarizing factor (EDHF). Additionally, our results indicated that extracellular Ca(2+) has an important role on the endothelium-dependent vasodilator effect induced by GSE.