In vivo bioavailability of polyphenols from grape by-product extracts, and effect on lipemia of normocholesterolemic Wistar rats.

BACKGROUND: The direct use of phenolic extracts from grape by-products can be useful when formulating functional food to improve consumer health. The use of phenolic extracts instead of pure polyphenols as an ingredient is relevant in this context. The present study investigated the bioavailability and absorption of polyphenols from grape by-product extracts and their health effect on cholesterolemia, by adding the extract (GE) to Wistar rats diet (50 g kg-1 ) in vivo. RESULTS: GE caused the appearance of (+)-catechin, myricetin and quercetic acid in plasma and liver. (+)-Catechin was the most abundant compound (6 µg mL-1 in plasma and 0.7 µg mg-1 protein in liver), whereas no phenolic compounds were detected in plasma or liver in the control group. Similarly, 3,4-hydroxyphenylacetic, a major product of polyphenol digestion, was detected in the plasma, liver and urine of the GE-group only. GE-group had significantly lower cholesterol level and lower total cholesterol/high-density lipoprotein ratio in plasma. Total bile acid content significantly increased in fecal matter after 24 h administration of the GE-enriched diet. CONCLUSION: Grape extract polyphenols are partially bioavailable and showed improvement in lipid metabolism. Thus, the results suggest that GE is promising as a functional ingredient in the prevention of hypercholesterolemia. © 2018 Society of Chemical Industry.

Molecular factors involved in the hypolipidemic- and insulin-sensitizing effects of a ginger (Zingiber officinale Roscoe) extract in rats fed a high-fat diet.

Hypolipidemic and hypoglycemic properties of ginger in animal models have been reported. However, information related to the mechanisms and factors involved in the metabolic effects of ginger at a hepatic level are limited. The aim of the present study was to investigate molecular factors involved in the hypoglycemic and hypolipidemic effects of a hydroethanolic ginger extract (GE) in the liver of rats fed a high-fat diet (HFD). The study was conducted in male Wistar rats divided into the following 3 groups: (i) Rats fed a standard diet (3.5% fat), the control group; (ii) rats fed an HFD (33.5% fat); and (iii) rats fed an HFD treated with GE (250 mg·kg-1·day-1) for 5 weeks (HFD+GE). Plasma levels of glucose, insulin, lipid profile, leptin, and adiponectin were measured. Liver expression of glycerol phosphate acyltransferase (GPAT), cholesterol 7 alpha-hydroxylase, peroxisome proliferator-activated receptors (PPAR), PPARα and PPARγ, glucose transporter 2 (GLUT-2), liver X receptor, sterol regulatory element-binding protein (SREBP1c), connective tissue growth factor (CTGF), and collagen I was measured. Data were analyzed using a 1-way ANOVA, followed by a Newman-Keuls test if differences were noted. The study showed that GE improved lipid profile and attenuated the increase of plasma levels of glucose, insulin, and leptin in HFD rats. This effect was associated with a higher liver expression of PPARα, PPARγ, and GLUT-2 and an enhancement of plasma adiponectin levels. Furthermore, GE reduced liver expression of GPAT, SREBP1c, CTGF, and collagen I. The results suggest that GE might be considered as an alternative therapeutic strategy in the management of overweight and hepatic and metabolic-related alterations.

Proanthocyanidins block aldosterone-dependent up-regulation of cardiac gamma ENaC and Nedd4-2 inactivation via SGK1.

Aldosterone plays a central role in the development of cardiac pathological states involving ion transport imbalances, especially sodium transport. We have previously demonstrated a cardioprotective effect of proanthocyanidins in aldosterone-treated rats. Our objective was to investigate for the first time the effect of proanthocyanidins on serum and glucocorticoid-regulated kinase 1 (SGK1), epithelial Na+ channel (γ-ENaC), neuronal precursor cells expressed developmentally down-regulated 4-2 (Nedd4-2) and phosphoNedd4-2 protein expression in the hearts of aldosterone-treated rats. Male Wistar rats received aldosterone (1mg kg-1day-1)+1% NaCl for 3weeks. Half of the animals in each group were simultaneously treated with the proanthocyanidins-rich extract (80% w/w) (PRO80, 5mg kg-1day-1). Hypertension and diastolic dysfunction induced by aldosterone were abolished by treatment with PRO80. Expression of fibrotic, inflammatory and oxidative mediators were increased by aldosterone-salt administration and blunted by PRO80. Antioxidant capacity was improved by PRO80. The up-regulated aldosterone mediator SGK1, ENaC and p-Nedd4-2/total Nedd4-2 ratio were blocked by PRO80. PRO80 blunted aldosterone-mineralocorticoid-mediated up-regulation of ENaC provides new mechanistic insight of the beneficial effect of proanthocyanidins preventing the cardiac alterations induced by aldosterone excess.

Beneficial effects of proanthocyanidins in the cardiac alterations induced by aldosterone in rat heart through mineralocorticoid receptor blockade.

Aldosterone administration in rats results in several cardiac alterations. Previous studies have demonstrated that proanthocyanidins, phenolic bioactive compounds, have cardioprotective effects. We studied the potential beneficial effects of the proanthocyanidin-rich almond skin extract (PASE) on the cardiac alterations induced by aldosterone-salt treatment, their effects in mineralocorticoid receptor activity and we sought to confirm proanthocyanidins as the specific component of the extract involved in the beneficial cardiac effects. Male Wistar rats received aldosterone (1 mg/Kg/day) +1% NaCl for 3 weeks. Half of the animals in each group were simultaneously treated with either PASE (100 mg/Kg/day) or spironolactone (200 mg/Kg/day). The ability of PASE to act as an antagonist of the mineralocorticoid receptor was examined using a transactivation assay. High performance liquid chromatography was used to identify and to isolate proanthocyanidins. Hypertension and diastolic dysfunction induced by aldosterone were abolished by treatment with PASE. Expression of the aldosterone mediator SGK-1, together with fibrotic, inflammatory and oxidative mediators were increased by aldosterone-salt treatment; these were reduced by PASE. Aldosterone-salt induced transcriptional activity of the mineralocorticoid receptor was reduced by PASE. HPLC confirmed proanthocyanidins as the compound responsible for the beneficial effects of PASE. The effects of PASE were comparable to those seen with the mineralocorticoid antagonist, spironolactone. The observed responses in the aldosterone-salt treated rats together with the antagonism of transactivation at the mineralocorticoid receptor by PASE provides evidence that the beneficial effect of this proanthocyanidin-rich almond skin extract is via as a mineralocorticoid receptor antagonist with proanthocyanidins identified as the compounds responsible for the beneficial effects of PASE.

Carob pod insoluble fiber exerts anti-atherosclerotic effects in rabbits through sirtuin-1 and peroxisome proliferator-activated receptor-γ coactivator-1α.

The aim of this study was to evaluate the potential effects of an insoluble dietary fiber from carob pod (IFC) (1 g ⋅ kg(-1) ⋅ d(-1) in the diet) on alterations associated with atherosclerosis in rabbits with dyslipidemia. Male New Zealand rabbits (n = 30) were fed the following diets for 8 wk: 1) a control diet (SF412; Panlab) as a control group representing normal conditions; 2) a control supplemented with 0.5% cholesterol + 14% coconut oil (DL) (SF302; Panlab) for 8 wk as a dyslipidemic group; and 3) a control containing 0.5% cholesterol + 14% coconut oil plus IFC (1 g ⋅ kg(-1) ⋅ d(-1)) (DL+IFC) for 8 wk. IFC was administered in a pellet mixed with the DL diet. The DL-fed group developed mixed dyslipidemia and atherosclerotic lesions, which were associated with endothelial dysfunction, inflammation, and fibrosis. Furthermore, sirtuin-1 (SIRT1) and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) protein expression in the aorta were reduced to 77% and 63% of the control group, respectively (P < 0.05), in these rabbits. Administration of IFC to DL-fed rabbits reduced the size of the aortic lesion significantly (DL, 15.2% and DL+IFC, 2.6%) and normalized acetylcholine-induced relaxation (maximal response: control, 89.3%; DL, 61.6%; DL+IFC, 87.1%; P < 0.05) and endothelial nitric oxide synthase expression (DL, 52% and DL+IFC, 104% of the control group). IFC administration to DL-fed rabbits also reduced cluster of differentiation 36 (DL, 148% and DL+IFC, 104% of the control group; P < 0.05), plasminogen activator inhibitor-1 (DL, 141% and DL+IFC, 107% of the control group), tumor necrosis factor-α (DL, 166% and DL+IFC, 120% of the control group), vascular cell adhesion molecule-1 (DL, 153% and DL+IFC, 110% of the control group), transforming growth factor-ß (DL, 173% and DL+IFC, 99% of the control group), and collagen I (DL, 157% and DL+IFC, 112% of the control group) in the aorta. These effects were accompanied by an enhancement of SIRT1 and PGC-1α (160% and 121% of the control group, respectively; P < 0.05) vascular expression. In summary, we demonstrated for the first time, to our knowledge, that administration of IFC reduces the development of atherosclerosis in rabbits. This effect seems to be related to an improvement in endothelial function and a reduction of inflammation and fibrosis, most probably as a consequence of the reduction of serum concentrations of cholesterol and triglycerides. Increased expression of aortic SIRT1 and PGC-1α could play an important role in the observed effects of IFC in rabbits with dyslipidemia.

Protective effect of a pomace olive oil concentrated in triterpenic acids in alterations related to hypertension in rats: mechanisms involved.

SCOPE: Despite the amount of information and research on the effects of virgin olive oil and its components in cardiovascular disease, little attention has been paid to the effects of pomace olive oil, an olive oil subproduct traditionally used in Spain. The aim of the present study was to evaluate the potential effects of a pomace olive oil concentrated in triterpenic acids (POCTA) on blood pressure, cardiac hemodynamics, and functional and molecular vascular alterations associated with hypertension in spontaneously hypertensive rats (SHR). METHODS AND RESULTS: The study showed that POCTA attenuated the increase of blood pressure in SHR. This effect was associated with an improvement in endothelium-dependent relaxation, enhancement of vascular expression of endothelial nitric oxide synthase, and reduction of tumor necrosis factor alpha, transforming growth factor beta, and collagen I. Furthermore, POCTA improved cardiac hemodynamics (left ventricular systolic pressure and left ventricular end-diastolic pressure) and decreased relative kidney and lung weights. CONCLUSION: POCTA exerts antihypertensive effects together with vascular and hypertension target organ protection in SHR. Since interest in pomace olive oil has been low, the results of this study contribute to increasing awareness of its biological and nutritional values.

Aged garlic extract improves adiponectin levels in subjects with metabolic syndrome: a double-blind, placebo-controlled, randomized, crossover study.

BACKGROUND: Garlic (Allium sativum) has been shown to have important benefits in individuals at high cardiovascular risk. The aim of the present study was to evaluate the effects of the administration of aged garlic extract (AGE) on the risk factors that constitute the cluster of metabolic syndrome (MS). METHODS AND DESIGN: Double-blind, crossover, randomized, placebo-controlled clinical trial to assess the effect of 1.2 g/day of AGE (Kyolic), for 24 weeks of treatment (12 weeks of AGE and 12 weeks of placebo), on subjects with MS. RESULTS: The administration of AGE increased the plasma levels of adiponectin (P = 0.027). No serious side effects associated with the intervention were reported. CONCLUSION: The present results have shown for the first time that the administration of AGE for 12 weeks increased plasma adiponectin levels in patients with MS. This suggests that AGE might be a useful, novel, nonpharmacological therapeutic intervention to increase adiponectin and to prevent cardiovascular (CV) complications in individuals with MS.

Papel del factor de crecimiento de tejido conectivo en el daño vascular asociado a hipertensión en ratas. Interacción con la aldosterona / Role of connective tissue growth factor in vascular damage associated with hypertension in rats. Interaction with aldosterone

Introducción. El factor de crecimiento de tejido conectivo (CTGF) está implicado en diversas enfermedades, como la aterosclerosis, la fibrosis de la piel y diversas nefritis experimentales y humanas. Sin embargo, el papel de este factor profibrótico en el daño vascular asociado a hipertensión no se conoce completamente. Objetivo. Estudiar el posible papel del CTGF en el daño vascular asociado a hipertensión en ratas, así como la posible interacción con la aldosterona. Método. Se utilizaron ratas macho espontáneamente hipertensas (SHR) tratadas durante 10 semanas con 2 dosis de eplerenona, un antagonista selectivo de los receptores de mineralocorticoides (30 y 100 mg/kg/día), y ratas normotensas (WKY) como grupo control. Al final del tratamiento se midió la presión arterial sistólica (PAS) y la reactividad vascular en anillos de aorta. Se determinó la expresión vascular y los valores de proteína del CTGF, así como la morfometría de la aorta. Se estudió también el efecto directo de la aldosterona en células de músculo liso vascular (CMLV). Resultados. Las SHR presentaron unos valores de PAS mayores que las ratas controles WKY. Sólo el tratamiento con la dosis alta de eplerenona redujo significativamente estos valores. La expresión vascular génica y los valores de proteínas del CTGF aumentaron significativamente en las SHR respecto a las WKY. El tratamiento con ambas dosis de eplerenona disminuyó significativamente estos parámetros. La relajación dependiente del endotelio fue menor en SHR que en WKY, y el tratamiento con eplerenona normalizó esta respuesta. Las áreas del vaso, la luz y la media aumentaron significativamente en las SHR respecto a las WKY, así como la relación media/luz. El tratamiento con eplerenona redujo todas las áreas estudiadas y normalizó la relación media/luz. La incubación de CMLV con aldosterona aumentó la expresión de CTGF de forma dependiente de la dosis. Conclusiones. La aldosterona participa en las alteraciones tanto funcionales como estructurales asociadas a la hipertensión arterial. El CTGF es uno de los factores implicados en el proceso fibrótico vascular asociado a hipertensión arterial (AU)

Introduction. Connective tissue growth factor (CTGF) is associated with distinct diseases, including atherosclerosis, skin fibrosis, and several human and experimental nephritides. However, the role of this profibrotic factor in the vascular damage associated with hypertension is not well known. Objective. To study the role of CTGF in vascular alterations associated with hypertension in rats, as well as its possible interaction with aldosterone. Method. Male spontaneously hypertensive rats (SHR) were treated with 2 doses (30 and 100 mg/Kg/day) of the mineralocorticoid receptor antagonist eplerenone for 10 weeks. Normotensive rats (WKY) were used as a control group. At the end of the treatment, systolic blood pressure (SBP) and vascular reactivity in aortic rings were measured. In addition, vascular expression and protein levels of CTGF, as well as morphological lesions in the aorta, were evaluated. The direct effect of aldosterone on vascular smooth muscle cells was also studied. Results. SBP was higher in SHR than in WKY and only the high dose of eplerenone significantly reduced SBP. In the aorta of SHR, CTGF mRNA expression and protein levels were upregulated compared with WKY. Both doses of eplerenone similarly and significantly diminished CTGF upregulation. Endothelium-dependent relaxation was lower in SHR than in WKY and treatment with eplerenone normalized this response. Vessel area, lumen area and media area, as well as the media to lumen ratio, were significantly increased in SHR compared with WKY. Treatment with eplerenone reduced all the parameters studied and normalized the media to lumen ratio. Incubation of cultured vascular smooth muscle cells with aldosterone increased CTGF production in a dose-dependent manner. Conclusions. Aldosterone participates in both the functional and structural alterations associated with hypertension. CTGF is one of the factors implicated in the vascular fibrotic process associated with hypertension (AU)

Interactions between aldosterone and connective tissue growth factor in vascular and renal damage in spontaneously hypertensive rats.

OBJECTIVE: The aim of the present study was to investigate possible inter-relationships between connective tissue growth factor (CTGF) and aldosterone in vascular and renal damage associated with hypertension. METHOD: Spontaneously hypertensive rats (SHR) were treated with two doses (100 and 30 mg/kg per day) of the mineralocorticoid receptor antagonist eplerenone, or with antihypertensive therapy (HHR) (20 mg/kg per day hydralazine + 7 mg/kg per day hydrochlorothiazide + 0.15 mg/kg per day reserpine). RESULTS: CTGF mRNA expression and protein levels in the aorta of SHR were upregulated (P < 0.05) compared with Wistar-Kyoto rats. Both doses of eplerenone similarly and significantly diminished CTGF upregulation, correlated with amelioration of aortic remodelling and endothelium-dependent relaxations. Only high-dose eplerenone and HHR significantly reduced arterial blood pressure. HHR treatment also diminished CTGF overexpression, suggesting a blood-pressure-mediated effect in CTGF regulation. This reduction, however, was lower (P < 0.05) than that produced by eplerenone (100 mg/kg per day). The direct effect of aldosterone on vascular smooth muscle cells was also studied. Incubation of cultured vascular smooth muscle cells with aldosterone increased CTGF production in a dose-related manner, but was reduced (P < 0.05) by the mineralocorticoid receptor antagonist spironolactone. Renal CTGF mRNA and protein levels were higher in SHR than in Wistar-Kyoto rats (P < 0.05), and were similarly diminished by all treatments (P < 0.05). CONCLUSIONS: These data show that aldosterone and haemodynamic stress from elevated blood pressure levels regulate vascular and renal CTGF in SHR. The results suggest that aldosterone, through CTGF stimulation, could participate in vascular and renal structural alterations associated with hypertension, describing a novel mechanism of aldosterone in hypertensive target organ damage.

Chronic l-arginine treatment reduces vascular smooth muscle cell hypertrophy through cell cycle modifications in spontaneously hypertensive rats.

OBJECTIVE: To investigate the effect of long-term l-arginine supplementation on phenotype and proliferative status of vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats (SHR) as well as the possible changes in nitric oxide (NO) availability. METHODS: Male SHR, 22 weeks of age, received l-arginine (660 mg/kg per day) in their drinking water for 12 weeks. VSMCs from untreated (C-VSMC) and l-arginine-treated (l-Arg-VSMC) SHR were isolated from the common carotid artery, cultured and used until passage five. Size, protein content, cell proliferation and ploidy were evaluated in carotid VSMCs in culture, as well as the possible association of NO in these changes. RESULTS: Relative cell size, total protein content per cell, and number of polyploid cells were significantly lower in l-Arg-VSMC compared to C-VSMC. Fetal calf serum stimulation (10% FCS) increased cell number only in l-Arg-VSMC. DNA synthesis, assessed by [H]methylthymidine incorporation after 10% FCS stimulation, was higher in l-Arg-VSMC than in C-VSMC. Cell cycle analysis revealed a significant increase of the number of l-Arg-VSMC at the G1 phase, together with a reduction at the G2 + M phase. In contrast, C-VSMC were arrested at the G2 + M phase of the cell cycle. Nitrite/nitrate levels, as well as intracellular cyclic guanosine monophosphate (cGMP) content, were significantly higher in l-Arg-VSMC. This was accompanied by enhanced inducible nitric oxide synthase (iNOS) expression and activity and a decreased constitutive nitric oxide synthase (cNOS) activity in these cells. CONCLUSIONS: The results suggest that chronic treatment with l-arginine induces changes in VSMC size, ploidy and cell cycle. These changes are accompanied by iNOS induction and stimulation of the NO-cGMP pathway.