Soy protein hydrolysate ameliorates cardiovascular remodeling in rats with l-NAME-induced hypertension

Red Quinoa Hydrolysates with Antioxidant Properties Improve Cardiovascular Health in Spontaneously Hypertensive Rats

In recent years, quinoa has been postulated as an emerging crop for the production of functional foods. Quinoa has been used to obtain plant protein hydrolysates with in vitro biological activity. The aim of the present study was to evaluate the beneficial effect of red quinoa hydrolysate (QrH) on oxidative stress and cardiovascular health in an in vivo experimental model of hypertension (HTN) in the spontaneously hypertensive rat (SHR). The oral administration of QrH at 1000 mg/kg/day (QrHH) showed a significant reduction in SBP from baseline (-9.8 ± 4.5 mm Hg; p < 0.05) in SHR. The mechanical stimulation thresholds did not change during the study QrH groups, whereas in the case of SHR control and SHR vitamin C, a significant reduction was observed (p < 0.05). The SHR QrHH exhibited higher antioxidant capacity in the kidney than the other experimental groups (p < 0.05). The SHR QrHH group showed an increase in reduced glutathione levels in the liver compared to the SHR control group (p < 0.05). In relation to lipid peroxidation, SHR QrHH exhibited a significant decrease in plasma, kidney and heart malondialdehyde (MDA) values compared to the SHR control group (p < 0.05). The results obtained revealed the in vivo antioxidant effect of QrH and its ability to ameliorate HTN and its associated complications.

Antihypertensive effect of soybean bioactive peptides: A review

Hypertension is a global disease that is extremely harmful to humans. Timely lowering of blood pressure is necessary in order to avoid the occurrence of corresponding complications. This review shows that soy peptides are beneficial in resisting hypertension. One of the advantages is the abundance of raw materials for producing soybean peptides. Secondly, there are no reports of adverse reactions due to soy peptides. Moreover, they exert protective effect against hypertension-induced complications such as long-term memory impairment and kidney damage. However, there are still some obstacles associated with the development of soybean peptides. Therefore, this review is focused on statistical analysis of peptide sequences, amino acid residues, and possible targets of anti-hypertensive soybean peptides. Eventually, it proposes that application of genetic engineering technology to specifically modify the N- and C-terminal of the soybean peptides, and possible targets in identifying the likely drug targets involved in the antihypertensive effects of these peptides.

PKR inhibitor imoxin prevents hypertension, endothelial dysfunction and cardiac and vascular remodelling in L-NAME-treated rats

AIMS

Hypertension is one of the leading causes of cardiovascular mortality and morbidity. It is associated with severe cardiac and vascular dysfunction. Double-stranded RNA-dependent protein kinase (PKR), is a known inducer of inflammation and apoptosis. However, no research has been done to elucidate the role of the PKR in an experimental model of hypertension, and related cardiovascular complications.

MAIN METHODS

L-NAME (N^G-Nitro-L-arginine-methyl ester) was used to induce the hypertension. Imoxin treatment was given to Wistar rats for the four weeks along with the L-NAME, to investigate the influence on the hypertension. Changes in physiological parameter were assessed by recording non-invasive blood pressure. Expression of PKR and downstream markers for inflammation, fibrosis, and vascular damage in rat heart and aorta was determined by western blot and immunohistochemistry. Histological examination and fibrosis assessment were done by using assay kits. Vascular reactivity was determined by ex-vivo isometric tension studies on rat aortic rings.

KEY FINDINGS

L-NAME-treated rats showed a significant increase in PKR expression followed by cardiac damage and vascular alterations compared to that of control animals. Results of western blot and immunohistochemistry indicate a significant increase in the inflammatory markers downstream to PKR. Endothelium-dependent vascular relaxation was significantly impaired in L-NAME administered rats. All effects of the L-NAME were attenuated by selective inhibition of PKR by imoxin.

SIGNIFICANCE

Alterations in the heart and vasculature could be mediated in part by activation of the PKR pathway. Hence selective inhibition of PKR has therapeutic potential for combating hypertension and associated cardiovascular complications.

Tripeptides Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP) Regulate the Proliferation and Migration of Vascular Smooth Muscle Cells by Interfering Ang II-Induced Human Umbilical Vein Endothelial Cells Derived EVs Delivering RNAs to VSMCs in the Co-culture Model

Angiotensin II (Ang II), a vasoactive factor in the renin-angiotensin-aldosterone system (RAAS), can regulate vasoconstriction and promote multiple vascular diseases. In this study, the effects of potent antihypertensive peptide Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP) on the proliferation and migration of vascular smooth muscle cells (VSMCs) by extracellular vesicles (EVs) from vascular endothelial cells (VECs) were studied using a cell co-culture model. The VEC-derived EVs were isolated, characterized, and investigated. The present study demonstrated that the EVs from Ang II-induced VECs could promote proliferation, migration, and inflammatory factors (IL-6 increased to 40.75 ± 4.33 pg/mL and IL-1β increased to 28.62 ± 5.42 pg/mL) generation of VSMCs, VPP and IPP exerted discrepant inhibitory effects on this pathway. The EVs with RNase treatment lost the effects on VSMCs, indicating that the RNAs packed into vesicles may be a critical component. These results implied that VPP and IPP could alleviate Ang II-induced vascular dysfunction by modulating the EV-mediated transmission of RNAs between VECs and VSMCs.

Dietary soya protein improves intra-myocardial lipid deposition and altered glucose metabolism in a hypertensive, dyslipidaemic, insulin-resistant rat model

This study investigates the effects of replacing dietary casein by soya protein on the underlying mechanisms involved in the impaired metabolic fate of glucose and lipid metabolisms in the heart of dyslipidaemic rats chronically fed (8 months) a sucrose-rich (62·5 %) diet (SRD). To test this hypothesis, Wistar rats were fed an SRD for 4 months. From months 4 to 8, half the animals continued with the SRD and the other half were fed an SRD in which casein was substituted by soya. The control group received a diet with maize starch as the carbohydrate source. Compared with the SRD-fed group, the following results were obtained. First, soya protein significantly (P<0·001) reduced the plasma NEFA levels and normalised dyslipidaemia and glucose homoeostasis, improving insulin resistance. The protein levels of fatty acid translocase at basal state and under insulin stimulation and the protein levels and activity of muscle-type carnitine palmitoyltransferase 1 were normalised. Second, a significant (P<0·001) reduction of TAG, long-chain acyl CoA and diacylglycerol levels was observed in the heart muscle. Third, soya protein significantly increased (P<0·01) GLUT4 protein level under insulin stimulation and normalised glucose phosphorylation and oxidation. A reduction of phosphorylated AMP protein kinase protein level was recorded without changes in uncoupling protein 2 and PPARα. Fourth, hydroxyproline concentration decreased in the left ventricle and hypertension was normalised. The new information provided shows the beneficial effects of soya protein upon the altered pathways of glucose and lipid metabolism in the heart muscle of this rat model.

Effect of arginine : lysine ratio in free amino acid and protein form onl-NAME induced hypertension in hypercholesterolemic Wistar rats

Arginine : lysine in the ratio of 5 : 1 plays an important role in cardiovascular diseases, especially as a nitric oxide precursor leading to vasodilation and inhibiting angiotensin-I converting enzyme in renin angiotensin system.

The Effect of Soy Intake on Metabolic Profiles of Women With Gestational Diabetes Mellitus

CONTEXT

To our knowledge, no study has examined the effects of soy intake on metabolic status of women with gestational diabetes mellitus (GDM).

OBJECTIVE

This study was designed to assess the effects of soy intake on metabolic status of GDM women.

METHODS

A randomized clinical trial was performed among 68 women with GDM. Women were randomly assigned to receive either a control diet containing 0.8-g/kg protein (70% animal and 30% plant proteins) (n = 34) or a soy diet containing the same amount of protein with 35% animal protein, 35% soy protein, and 30% other plant proteins (n = 34) for 6 weeks.

RESULTS

Compared with soy protein consumption, the control group significantly increased fasting plasma glucose (+1.4 ± 11.6 vs -12.7 ± 13.2 mg/dL, P < .001), serum insulin levels (+5.0 ± 11.6 vs -0.9 ± 10.0 μIU/mL, P = .02), homeostasis model of assessment-insulin resistance (+1.2 ± 2.7 vs -0.8 ± 2.2, P = .002), and decreased quantitative insulin sensitivity check index (-0.007 ± 0.02 vs +0.01 ± 0.03, P = .004). Administration of the control diet resulted in a significant difference in serum triglycerides changes (+31.3 ± 38.0 vs +8.9 ± 46.1 mg/dL, P = .03) compared with soy protein. There were a significant decrease in total antioxidant capacity (-35.0 ± 136.2 vs +81.8 ± 188.8 mmol/L, P = .005) and glutathione (-41.3 ± 145.7 vs +53.3 ± 117.3 μmol/L, P = .004) by the control diet intake compared with soy protein. The control diet group had a higher incidence of newborn hyperbilirubinemia (32.4% vs 8.8%, P = .01) and newborn hospitalization (20.6% vs 2.9%, P = .02) compared with soy protein.

CONCLUSION

Soy protein consumption in women with GDM significantly improved the glucose homeostasis parameters, triglycerides, and biomarkers of oxidative stress, as well as reductions in the incidence of newborn hyperbilirubinemia and hospitalizations.

Oral administration of veratric acid, a constituent of vegetables and fruits, prevents cardiovascular remodelling in hypertensive rats: a functional evaluation

In our previous studies, veratric acid (VA) shows beneficial effect on hypertension and its associated dyslipidaemia. In continuation, this study was designed to investigate the effect of VA, one of the major benzoic acid derivatives from vegetables and fruits, on cardiovascular remodelling in hypertensive rats, primarily assessed by functional studies using Langendorff isolated heart system and organ bath system. Hypertension was induced in male albino Wistar rats by oral administration of N ω -nitro-l-arginine methyl ester hydrochloride (l-NAME) (40 mg/kg body weight (b.w.)) in drinking water for 4 weeks. VA was orally administered at a dose of 40 mg/kg b.w. l-NAME-treated rats showed impaired cardiac ventricular and vascular function, evaluated by Langendorff isolated heart system and organ bath studies, respectively; a significant increase in the lipid peroxidation products such as thiobarbituric acid-reactive substances and lipid hydroperoxides in aorta; and a significant decrease in the activities of superoxide dismutase, catalase, glutathione peroxidase and levels of GSH, vitamin C and vitamin E in aorta. Fibrotic remodelling of the aorta and heart were assessed by Masson's Trichrome staining and Van Gieson's staining, respectively. In addition, l-NAME rats showed increased heart fibronectin expression assessed by immunohistochemical analysis. VA supplementation throughout the experimental period significantly normalised cardiovascular function, oxidative stress, antioxidant status and fibrotic remodelling of tissues. These results of the present study conclude that VA acts as a protective agent against hypertension-associated cardiovascular remodelling.

Vanillic acid: a potential inhibitor of cardiac and aortic wall remodeling in l-NAME induced hypertension through upregulation of endothelial nitric oxide synthase

The objective of the present study is to investigate the effects of vanillic acid on blood pressure, cardiac marker enzymes, left ventricular function and endothelial nitric oxide synthase (eNOS) expression in N(ω)-nitro-l-arginine methyl ester hydrochloride (l-NAME) induced hypertension in male albino Wistar rats. In hypertensive rats, mean arterial pressure (MAP), heart rate, cardiac marker enzymes and organ weight were increased. Impaired left ventricular function and decreased aortic eNOS expression was also observed in hypertensive rats. Moreover, treatment with vanillic acid exhibited beneficial effect on blood pressure, left ventricular function and cardiac marker enzymes. In addition, treatment with vanillic acid on hypertensive rats had upregulated eNOS expression and showed beneficial effects evidenced by histopathology and ultrastructural observations of aorta. In conclusion, vanillic acid has enough potential to normalize hypertension and left ventricular function in l-NAME induced hypertensive rats. With additional studies, vanillic acid might be used as a functional drug or as an adjuvant in the management of hypertension.

Decrease in IL-10 and increase in TNF-α levels in renal tissues during systemic inhibition of nitric oxide in anesthetized mice

Earlier, we demonstrated that the inhibition of nitric oxide synthase (NOS) by nitro‐l‐arginine methyl ester (l‐NAME) infusion increases the endogenous production of proinflammatory cytokine, tumor necrosis factor (TNF‐α). In the present study, we examined the hypothesis that inhibition of nitric oxide (NO) production leads to the suppression of interleukin (IL)‐10 (anti‐inflammatory cytokine) generation which facilitates the enhancement of TNF‐α production endogenously. Using appropriate enzyme‐linked immunosorbent assay kits and immunohistochemical staining, the levels of IL‐10 and TNF‐α in plasma (P) and in renal tissues (R) were measured in anesthetized mice (C57BL/6; ~10 weeks age; n = 6/group) infused with or without l‐NAME (200 μg/min/kg; i.v. for 2 h). Compared to vehicle‐treated control mice, l‐NAME‐treated mice had a lower level of IL‐10 (P, 0.3 ± 0.1 vs. 2.6 ± 0.6 ng/mL; R, 0.5 ± 0.1 vs. 3 ± 0.1 ng/mg protein) and a higher level of TNF‐α (P, 432 ± 82 vs. undetected pg/mL; R, 58 ± 7 vs. 6 ± 5 pg/mg protein). IL‐10 protein expression, present mostly in the distal nephron segments in control mice, was markedly downregulated in l‐NAME‐treated mice. Compared to control mice, TNF‐α expression increased 2.5‐fold in renal cortical sections (mostly in the distal nephron segments) in l‐NAME‐treated mice. Coinfusion of a NO donor, S‐nitroso‐N‐acetyl‐penicillamine (SNAP; 25 μg/min/kg) with l‐NAME in a separate group of mice prevented these changes in IL‐10 and TNF‐α induced by l‐NAME. IL‐10 infusion (0.075 ng/min/g) in l‐NAME‐treated mice markedly attenuated l‐NAME‐induced increments in TNF‐α. Thus, these results demonstrate that NOS inhibition decreases endogenous IL‐10 generation and thus, minimizes its immune downregulating action on the TNF‐α production in the kidney.

In this study in mice, we examined the hypothesis that NOS inhibition reduces the endogenous production of anti‐inflammatory cytokine, IL‐10 which facilitates enhanced production of TNF‐α in the kidney. Using appropriate enzyme‐linked immunosorbent assay kits and immunohistochemical staining, levels of IL‐10 and TNF‐α in renal tissue were measured in anesthetized mice infused with or without l‐NAME (200 μg/min/kg) in the presence or absence of a NO donor, S‐nitroso‐N‐acetyl‐penicillamine (SNAP; 25 μg/min/kg) or IL‐10 infusion (0.075 ng/min/g). These results demonstrate that NOS inhibition decreases endogenous IL‐10 generation and thus, minimizes its immune downregulating action on the TNF‐α production in the kidney.

Hypotensive and vasorelaxant effects of sericin-derived oligopeptides in rats

Sericin-derived oligopeptides obtained from silk cocoons were investigated for the in vivo hypotensive effect and investigated for the underlying mechanism involved in vasodilation in isolated rat thoracic aorta. In normotensive anesthetized rats, oligopeptides induced an immediate and transient hypotensive activity. In rat aortic rings, oligopeptides induced a concentration-dependent vasorelaxation in vessels precontracted with both KCl and phenylephrine (PE) with endothelium-intact or endothelium-denuded rings. In endothelium-intact rings, pretreatment with Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME, 100 µM), an inhibitor of the NO synthase (NOS) or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 1 µM), a selective inhibitor of the guanylyl cyclase enzyme, significantly reduced the relaxant effect of oligopeptides. However, indomethacin, an inhibitor of the cyclooxygenase, had no effect on oligopeptides-induced relaxation. In addition, pretreatment with tetraethylammonium (TEA, 5 mM) reduced the maximal relaxant effect induced by oligopeptides. By contrast, relaxation was not affected by 4-aminopyridine (4-AP, 1 mM), glibenclamide (10 µM), or barium chloride (BaCl₂, 1 mM). In depolarization Ca²⁺-free solution, oligopeptides inhibited calcium chloride- (CaCl₂-) induced contraction in endothelium-denuded rings in a concentration-dependent manner. Nevertheless, oligopeptides attenuated transient contractions in Ca²⁺-free medium containing EGTA (1 mM) induced by 1 µM PE, but they were not affected by 20 mM caffeine. It is obvious that potent vasodilation effect of oligopeptides is mediated through both the endothelium and the vascular smooth muscle.

The renin-angiotensin system in adipose tissue and its metabolic consequences during obesity

Obesity is a worldwide disease that is accompanied by several metabolic abnormalities such as hypertension, hyperglycemia and dyslipidemia. The accelerated adipose tissue growth and fat cell hypertrophy during the onset of obesity precedes adipocyte dysfunction. One of the features of adipocyte dysfunction is dysregulated adipokine secretion, which leads to an imbalance of pro-inflammatory, pro-atherogenic versus anti-inflammatory, insulin-sensitizing adipokines. The production of renin-angiotensin system (RAS) components by adipocytes is exacerbated during obesity, contributing to the systemic RAS and its consequences. Increased adipose tissue RAS has been described in various models of diet-induced obesity (DIO) including fructose and high-fat feeding. Up-regulation of the adipose RAS by DIO promotes inflammation, lipogenesis and reactive oxygen species generation and impairs insulin signaling, all of which worsen the adipose environment. Consequently, the increase of circulating RAS, for which adipose tissue is partially responsible, represents a link between hypertension, insulin resistance in diabetes and inflammation during obesity. However, other nutrients and food components such as soy protein attenuate adipose RAS, decrease adiposity, and improve adipocyte functionality. Here, we review the molecular mechanisms by which adipose RAS modulates systemic RAS and how it is enhanced in obesity, which will explain the simultaneous development of metabolic syndrome alterations. Finally, dietary interventions that prevent obesity and adipocyte dysfunction will maintain normal RAS concentrations and effects, thus preventing metabolic diseases that are associated with RAS enhancement.

Novel diallyldisulfide analogs ameliorate cardiovascular remodeling in rats with L-NAME-induced hypertension

Diallyldisulfide (DADS), an active principle of garlic (Allium sativum) is known for its antihypertensive properties. The present study was designed to evaluate the effect of novel DADS analogs, against L-NAME induced hypertension in Wistar rats. The daily administration of L-NAME (50mg/kg) for six weeks along with DADS analogs (20 mg/kg) significantly decreased the elevated systolic blood pressure (SBP) and the activity of angiotensin converting enzyme (ACE) and also inhibited the decline in nitrite/nitrate (NO(x)) concentrations and cyclic guanosine monophosphate (cGMP) levels. Adverse changes such as lipid peroxidation, protein damage and a decrease in the levels of antioxidant enzymes, were rectified after the administration of DADS analogs. Oral administration of DADS analogs preserved the expression of endothelial nitric oxide synthase (eNOS). The ability of the DADS analogs to inhibit L-NAME induced hypertension was compared with Enalapril (15 mg/kg), which was taken as a standard. The DADS analogs prevented L-NAME-induced cardio toxicity, which was also reflected at the microscopic level indicative of its cardio protective effects. DADS analogs induced vasorelaxation was completely abolished by the removal of the endothelium or by pre-treatment with L-NAME, an inhibitor of nitric oxide synthase. DADS analogs inhibited the calcium influx induced by phenylephrine (0.3 μM) and high K(+) (60mM) and this effect was completely abolished by pretreatment of L-NAME. Taken together, our results show that the DADS analogs induce vasorelaxation and have antihypertensive properties, which may be mediated through activation of eNOS.

Tetrahydrocurcumin alleviates hypertension, aortic stiffening and oxidative stress in rats with nitric oxide deficiency

Tetrahydrocurcumin (THC), a major metabolite of curcumin, possesses strong antioxidant and cardioprotective properties. However, the activities of THC in hypertension and its associated complications remain unknown. The aim of this study was to investigate the effect of THC on hemodynamic status, aortic elasticity and oxidative stress in rats with N-nitro-L-arginine methyl ester (L-NAME)-induced hypertension. Hypertension was induced in male Sprague-Dawley rats by administration of L-NAME (50 mg kg(-1) body weight) in drinking water for 5 weeks. THC at a dose of 50 or 100 mg kg(-1) per day was administered daily during the fourth and fifth weeks when the hypertensive state had been established. The effects of THC on hemodynamics, aortic elasticity, endothelial nitric oxide synthase (eNOS) protein expression and oxidative stress markers were assessed. Marked increases in blood pressure, peripheral vascular resistance, aortic stiffness and oxidative stress were found in rats after L-NAME administration. THC significantly reversed these deleterious effects by reducing aortic wall thickness and stiffness. These effects were associated with increased aortic eNOS expression, elevated plasma nitrate/nitrite, decreased oxidative stress with reduced superoxide production and enhanced blood glutathione. Our results provide the first evidence that THC attenuates the detrimental effect of L-NAME by improving the hemodynamic status and aortic elasticity concomitant with reduction of oxidative stress. The present study suggests that THC might be used as a dietary supplement to protect against cardiovascular alterations under nitric oxide-deficient conditions.

Involvement of tumor necrosis factor-alpha in natriuretic response to systemic infusion of nitric oxide synthase inhibitor in anesthetized mice

Systemic infusion of TNF-alpha exerts renal vasoconstriction but caused marked natriuresis in mice. Similar renal responses were also observed during systemic infusion of nitric oxide (NO) synthase inhibitors as opposed to their usual antinatriuretic responses when administered intrarenally. In the present study, we examined the hypothesis that acute NO blockade systemically induces TNF-alpha generation. which induces this natriuretic response. Renal responses to intravenous infusion of the NO synthase inhibitor nitro-L-arginine methyl ester (L-NAME; 0.2 microg x min(-1) x g body wt(-1) for 85 min) and its impact on the plasma level of TNF-alpha were evaluated in anesthetized mice. Plasma TNF-alpha was undetected in untreated mice (n = 7) but was elevated in L-NAME-treated mice (109 +/- 22 pg/ml; P < 0.01 vs. untreated group; n = 7) along with an increase in TNF-alpha protein expression in kidney tissue. L-NAME infusion caused a usual increase in mean arterial pressure (MAP; 98 +/- 3 to 122 +/- 3 mmHg; P < 0.01) and decreases in renal blood flow (RBF; 8.6 +/- 0.3 to 4.4 +/- 0.2 ml x min(-1) x g(-1); P < 0.01) and glomerular filtration rate (GFR; 1.14 +/- 0.07 to 0.77 +/- 0.04 ml x min(-1) x g(-1); P < 0.01) with a marked increase in sodium excretion (U(Na)V; 0.48 +/- 0.10 to 3.52 +/- 0.85 micromol x min(-1) x g(-1); P < 0.01). Interestingly, in mice (n = 7) pretreated with the TNF-alpha blocker etanercept (5 mg/kg sc), the U(Na)V response to l-NAME infusion was markedly blunted (0.58 +/- 0.08 to 1.22 +/- 0.28 micromol x min(-1) x g(-1); P = NS) although responses for MAP, RBF, and GFR were mostly unchanged. However, pretreatment with the superoxide scavenger tempol in mice (n = 7) did not alter the U(Na)V response to L-NAME. These data demonstrate that L-NAME-induced natriuresis is mediated, at least in part, by concomitant generation of TNF-alpha during NO blockade.