Yuuka Mukai

Polyphenol-containing azuki bean (Vigna angularis) seed coats attenuate vascular oxidative stress and inflammation in spontaneously hypertensive rats.

We investigated the effects of azuki bean (Vigna angularis) seed coats (ABSC), which contain polyphenols, on the vascular oxidative stress and inflammation associated with hypertension. Spontaneously hypertensive rats (SHR) and control normotensive Wistar-Kyoto (WKY) rats were divided into 2 groups each. One group was fed 0% ABSC; the other, a 1.0% ABSC-containing diet. Tail systolic blood pressure (SBP) was examined throughout ABSC treatment. At 8 weeks, vascular superoxide (O(2)(-)) production was measured by lucigenin-enhanced chemiluminescence. mRNA expressions of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, macrophage chemoattractant protein-1 (MCP-1) and its receptor C-C chemokine receptor 2 (CCR2) in the aorta were analyzed by reverse transcriptase-polymerase chain reaction. Protein expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were determined by western blotting. Polyphenol-containing ABSC suppressed the elevation of SBP throughout the treatment period. The NADPH-stimulated O(2)(-) level decreased significantly in the aorta of ABSC-treated SHR compared with the level of untreated SHR. The p47phox and Nox4 mRNA expression increased significantly in untreated SHR compared with that in WKY rats. Conversely, the level of p47phox mRNA was significantly lower in ABSC-treated SHR than in untreated SHR. The protein abundance of both iNOS and COX-2 was significantly decreased in the aorta of the ABSC-treated SHR compared with this abundance in untreated SHR. The MCP-1 and CCR2 mRNA expressions increased in untreated SHR, and these levels were significantly lower in ABSC-treated SHR. In conclusion, our results suggested that polyphenol-containing ABSC could attenuate vascular oxidative stress and inflammation during the progression of hypertension, and this may lead to an improvement in hypertension.

Polyphenol-containing azuki bean (Vigna angularis) extract attenuates blood pressure elevation and modulates nitric oxide synthase and caveolin-1 expressions in rats with hypertension.

BACKGROUND AND AIMS Azuki beans (Vigna angularis) contain polyphenols such as proanthocyanidins that exhibit potential radical scavenging activities. We herein investigated the effects of polyphenol-containing azuki bean extract (ABE) on elevated blood pressure, nitric oxide (NO) production, and expressions of endothelial NO synthase (eNOS), inducible NOS (iNOS), and caveolin-1 proteins in the aorta and kidney of chronically hypertensive rats. METHODS AND RESULTS Spontaneously hypertensive rats (SHRs/Izm) with approximately 200 mm Hg systolic blood pressure (SBP) were randomly divided into 2 groups fed either 0% or 0.9% ABE-containing diet. Age-matched normotensive Wistar-Kyoto rats were used as the control. The content of 24-h urinary nitrate/nitrite (NOx) excretion was measured to evaluate NO production. After 8 weeks of treatment, the eNOS, iNOS, and caveolin-1 protein expressions in the aorta and kidney were analyzed by western blotting. The SBP of the ABE-treated SHR was significantly lower than that of the untreated SHR. The level of 24-h urinary NOx excretion was significantly higher in the ABE-treated SHR than in the untreated SHR. The eNOS and iNOS expressions in the aorta and kidney were remarkably upregulated in the untreated SHR but suppressed in the ABE-treated SHR. The vascular and renal caveolin-1 expressions were upregulated in the ABE-treated SHR. CONCLUSIONS ABE reduced the elevated blood pressure and increased NO production in long-term treatment. It may be associated with the modulation of eNOS and iNOS protein expressions in the aorta and kidney during the development of hypertension.

EFFECT OF POLYPHENOL-CONTAINING AZUKI BEAN (VIGNA ANGULARIS) EXTRACT ON BLOOD PRESSURE ELEVATION AND MACROPHAGE INFILTRATION IN THE HEART AND KIDNEY OF SPONTANEOUSLY HYPERTENSIVE RATS

1 Hypertension is a major risk factor for myocardial infarction and renal damage, and it has also been shown to have pro‐inflammatory actions that increase the formation of reactive oxygen species. Macrophage infiltration has been suggested to play a role in the pathogenesis of hypertension. Azuki beans are known to contain pro‐anthocyanidins, a group of polyphenolic bioflavonoids with remarkable radical‐scavenging activities in vitro. Therefore, the aim of the present study was to investigate the effect of polyphenol‐containing azuki bean extract (ABE) on systolic blood pressure (SBP) and macrophage infiltration in the heart and kidney of spontaneously hypertensive rats (SHR). 2 Spontaneously hypertensive rats and control normotensive Wistar‐Kyoto (WKY) rats were divided into two groups fed either 0 or 0.8% ABE in their diets. Tail SBP and macrophage kinetics in the heart and kidney were examined. 3 The SBP of the SHR group was higher than that of age‐matched WKY rats throughout the treatment period. After 8 weeks of treatment, the increased SBP in ABE‐treated SHR was significantly less than that in untreated SHR. 4 Nicotinamide adenine dinucleotide (NADH) or nicotinamide adenine dinucleotide phosphate (NADPH)‐stimulated superoxide () production was enhanced in the kidney and heart in SHR and WKY rats compared with levels in the absence of NADH or NADPH. The NADPH‐stimulated levels in the kidney in untreated SHR was significantly higher than that in untreated WKY rats. The levels in ABE‐treated SHR were significantly decreased compared with the untreated SHR group. 5 In immunohistochemical analyses, the number of macrophages in the heart and in the glomeruli and tubulointerstitium of the kidney was significantly higher in ABE‐untreated SHR than in ABE‐untreated WKY rats. Conversely, there was a significant decrease in the number of macrophages in ABE‐treated SHR compared with the untreated SHR. There were significant positive correlations between SBP and the number of ED1‐positve macrophages in the heart and tubulointerstitial and glomerular areas of the kidney in WKY rats and SHR. 6 In conclusion, the results of the present study suggest that ABE attenuates the elevation of SBP and macrophage infiltration in the heart, as well as in the glomeruli and tubulointerstitium of the kidney, in our SHR model.

Fructose intake during pregnancy up-regulates the expression of maternal and fetal hepatic sterol regulatory element-binding protein-1c in rats

Excess fructose consumption is associated with the development of type 2 diabetes and obesity. However, the impact of fructose intake on maternal and fetal lipid metabolism during pregnancy is not known. The aim of this study was to examine whether maternal fructose intake during pregnancy would affect fetal and maternal hepatic lipid metabolism. Pregnant Wistar rats were randomly divided into untreated control and fructose-treated groups; the fructose-treated group received fructose via drinking water throughout pregnancy. On gestational day 20, glucose and insulin concentration in the maternal plasma were measured. The mRNA expression of sterol regulatory element-binding protein (SREBP)-1c and its target genes in the liver of dams and fetuses were analyzed by real-time PCR. Significantly higher maternal plasma glucose levels, indicating hyperglycemia, was observed in the fructose-treated group than in the control group. Furthermore, the fructose-treated group showed significantly higher expression levels of both maternal and fetal SREBP-1c mRNA and protein and significantly elevated expression of fatty acid synthase; the group also showed reduced acyl-CoA oxidase levels in the maternal liver. Thus, our results suggest that maternal fructose intake during pregnancy causes maternal hyperglycemia and up-regulates hepatic SREBP-1c expression in both fetuses and dams. This may lead to defects in carbohydrate and lipid metabolism in the adult offspring.

Azuki bean polyphenols intake during lactation upregulate AMPK in male rat offspring exposed to fetal malnutrition.

OBJECTIVE Fetal malnutrition is an early-life inducer of dyslipidemia and glucose intolerance. The aim of this study was to examine whether maternal azuki bean (Vigna angularis) polyphenol (AP) intake during lactation affects the adenosine monophosphate-activated protein kinase (AMPK) pathway and lipid metabolism in offspring exposed to fetal malnutrition. METHODS Pregnant Wistar rats were divided into three groups: a control diet offered during gestation and lactation (CC), a low-protein diet during gestation and a control diet during lactation (LPC); and a low-protein diet during gestation and a 1.0% AP-containing control diet during lactation (LPAP). Male pups were randomly selected for the study; half the pups were sacrificed at 3 wk of age and the other half were fed a standard diet and sacrificed at 23 wk. Hepatic triacylglycerol levels, phosphorylation levels of AMPK and acetyl-coenzyme A carboxylase (ACC), and mRNA levels of sterol regulatory element-binding protein-1c (SREBP-1c) were evaluated. RESULTS Significant decreases in body weights and hepatic triacylglycerol levels were found in the LPAP compared with the LPC group. Plasma adiponectin levels in the LPAP group were higher than those in the LPC group. AMPK phosphorylation was upregulated in the livers and skeletal muscles in young and adult LPAP compared with LPC rats. ACC phosphorylation was upregulated in skeletal muscles of LPAP rats. SREBP-1c mRNA expression was decreased in the livers of LPAP rats. CONCLUSION Our results suggest that maternal AP intake during lactation upregulates AMPK phosphorylation not only in young but also in adult offspring exposed to fetal malnutrition and may lead to decreased hepatic lipid accumulation by ACC phosphorylation and downregulation of SREBP-1c expression.

Maternal fructose intake during pregnancy modulates hepatic and hypothalamic AMP-activated protein kinase signalling in a sex-specific manner in offspring

Dietary fructose ingestion during gestation affects carbohydrate metabolism in the offspring. In the present study, we investigated the effects of excess fructose intake during pregnancy on hepatic and hypothalamic AMP‐activated kinase (AMPK) expression and phosphorylation, as well as hepatic glucose‐6‐phosphatase (G6Pase) activity in offspring. Pregnant Wistar rats received normal chow and 100 g/L fructose solution or normal water during gestation ad libitum. On gestational Day 21, some dams were killed and plasma samples and fetuses were collected. The remaining dams received normal water after spontaneous delivery during lactation. Pups were killed on postnatal Day 22 and the plasma, liver and hypothalamus were collected and analysed. Plasma glucose and insulin levels increased in female but not male offspring in the fructose group. Although the mRNA and total protein levels of AMPKα were unchanged, levels of phosphorylated AMPKα protein in the fructose group of female offspring were significantly lower in the liver and 4.6‐fold higher in the hypothalamus. The hepatic protein level of sirtuin 1, which is involved in AMPK phosphorylation and activation, was significantly reduced in the fructose group of female offspring. The activity of G6Pase, which plays a role in gluconeogenesis, was significantly enhanced in the liver of female offspring from fructose‐fed dams. These changes were not observed in male offspring. In conclusion, we found that excessively high fructose intake during pregnancy may modulate the hepatic and hypothalamic AMPK signalling pathways in female offspring after birth.

Lignophenols Decrease Oleate-Induced Apolipoprotein-B Secretion in HepG2 Cells

Lignin is one of the components in the plant cell wall, after cellulose, making up 20-30% of the global plant biomass. Lignophenols (LPs) are derivatives of lignin with high phenolic function and antioxidant properties. However, their medicinal property is not well characterised. Apolipoprotein-B (apo-B) is an essential component in very low-density lipoprotein, and high levels of serum apolipoprotein-B (apo-B) are a major factor for coronary heart disease. In this study, we examined the effect of lignophenols on apo-B secretion in HepG2 cells. HepG2 cells were treated with varying concentrations of LPs and 0.8 mm sodium oleate. LPs decreased oleate-induced apo-B secretion in a dose-dependent manner. LPs also decreased oleate-induced microsomal triglyceride transfer protein (MTTP) mRNA expression and cellular total cholesterol, suggesting that lipid bioavailability and lipidation of lipoprotein are likely involved in the decreased secretion of apo-B. Furthermore, LPs decreased oleate-induced mature sterol regulatory element binding protein 2 (SREBP-2), a transcription factor that activates cholesterol biosynthesis. This is the first study to show that LPs can decrease oleate-induced apo-B secretion in HepG2 cells. The modulations of MTTP mRNA expression, cellular total cholesterol metabolism and mature SREBP-2 expression may be important factors in the regulation of apo-B secretion by LPs.

Long-term effect of green tea extract during lactation on AMPK expression in rat offspring exposed to fetal malnutrition

OBJECTIVE The fetal and neonatal environments are important determinants of disease risk in adult life. The aim of this study was to determine whether maternal green tea extract (GTE) intake during lactation affects the expression and activity of adenosine monophosphate-activated protein kinase (AMPK) in the kidneys of male offspring of protein-restricted dams during gestation. METHODS Pregnant Wistar rats were fed control (C) or low-protein diets (LP) during gestation. Following delivery, dams received a control or GTE-containing control diet during lactation as follows: C on control diet (CC), LP on control diet (LPC), LP on 0.12% GTE-containing control diet (LPL), or LP on 0.24% GTE-containing control diet (LPH). Some of the male pups from each dam were sacrificed at week 3, and the remaining male pups were fed a standard diet and sacrificed at week 30. Blood chemistry and expression levels of AMPKα, mammalian target of rapamycin (mTOR), and Akt in the kidneys of the male offspring were examined. RESULTS The level of phosphorylated AMPKα in the LPH group at week 3 was higher than that in the LPC group. At week 30, the protein levels of total and phosphorylated AMPK in the LPL and LPH groups were lower than those in the LPC group. The protein levels of mTOR and Akt at week 30 in the LPL and LPH groups were lower than those in the LPC group. CONCLUSION GTE intake during lactation modulates AMPK, Akt, and mTOR expression in the kidneys of the adult male offspring of dams fed a protein-restricted diet and may induce long-term alterations in the expressions of these proteins in the kidneys.

Lignin-derived lignophenols attenuate oxidative and inflammatory damage to the kidney in streptozotocin-induced diabetic rats

Abstract This study investigated the effects of lignin-derived lignophenols (LPs) on the oxidative stress and infiltration of macrophages in the kidney of streptozotocin (STZ)-induced diabetic rats. The diabetic rats were divided into four groups with 0%, 0.11%, 0.33% and 1.0% LP diets. The vehicle-injected controls were given a commercial diet. At 5 weeks, superoxide (O2−) production, macrophage kinetics, the degree of fibrosis in glomeruli and mRNA expression for monocyte chemoattractant protein-1 (MCP-1) were examined. The NADPH-stimulated O2− levels in the kidney of the diabetic rats treated with 1.0% LP were significantly lower than those in untreated diabetic rats. The number of macrophages, levels of MCP-1 mRNA expression and degree of glomerular fibrosis increased in untreated LP and these levels were significantly lower in 1.0%LP-treated rats. The results suggested that LPs suppress the excess oxidative stress, the infiltration and activation of macrophages and the glomerular expansion in STZ-induced diabetic kidneys.

Green Tea Extract Increases mRNA Expression of Enzymes Which Influence Epigenetic Marks in Newborn Female Offspring from Undernourished Pregnant Mother

Biochemical and toxicological properties of catechin remain unclear, e.g.; how catechin affects female offspring from undernourished pregnant dams. Here, to elucidate effects of low prenatal protein on female offspring health status, changes of enzymes which modify epigenetic marks related with metabolism in kidneys from newborns were investigated after continuously administering catechin extracted from green tea to lactating maternal rats after pregnant undernourishment. We found that green tea extract intake during lactation up-regulated the activation of AMP-activated protein kinase in young female offspring from protein-restricted dams and modulated the AMP-activated protein kinase pathway in the kidney. This pathway was indicated to be stimulated by SIRT1 gene expression. The feeding of green tea extract to protein-restricted dams during lactation is likely to up-regulate AMP-activated protein kinase activation and may partly lead to alterations of the AMP-activated protein kinase pathway in female offspring kidneys. In addition, energy metabolism in fetal and offspring period with green tea extract administration might be related to enzymes which modify epigenetic marks such as DNA methyltransferase 1 and 3a.