Resveratrol and lycopene ameliorate contrast-induced nephropathy in a rabbit model

Oxidative stress appears to possess a central role in CIN pathophysiology. Resveratrol (Res) and lycopene (Lyc) are strong natural antioxidants evaluated in a limited number of CIN animal studies in vivo. The aim of the study was to evaluate the potential renoprotective effects of Res/Lyc in a CIN rabbit model. Twenty-four adult male New Zealand white rabbits were equally assigned into four groups: control (saline), CIN (intravenous iopromide; 7.5 g iodine/kg), Res + CIN (per os Res; 5 mg/kg), and Lyc + CIN (per os Lyc; 4 mg/kg). Serum Cr (sCr); symmetric/asymmetric dimethylarginine (SDMA/ADMA); oxidative stress biomarkers: malondialdehyde; total antioxidant capacity; catalase; glutathione) were evaluated in blood samples at three time points: right after (0 h); 24 h; 48 h after iopromide/saline administration. CD20⁺/CD3⁺ lymphocytes were determined (48 h). All animals were sacrificed at 48 h and both kidneys collected. Oxidative stress biomarkers were measured in renal tissue. sCr and SDMA/ADMA levels increased significantly in CIN compared to all groups. Oxidative stress secondary to CIN in blood/kidneys was suppressed by Res/Lyc. B and T lymphocytes decreased significantly in CIN compared to all groups. The present study provides emerging evidence that Res/Lyc ameliorate CIN by modulating oxidant/antioxidant balance in blood/renal tissue and by inhibiting vasoconstriction/blood cytotoxicity.

SIRT1-mediated deacetylation of NF-κB inhibits the MLCK/MLC2 pathway and the expression of ET-1, thus alleviating the development of coronary artery spasm

Coronary artery spasm (CAS) is an intense vasoconstriction of coronary arteries that causes total or subtotal vessel occlusion. The cardioprotective effect of sirtuin-1 (SIRT1) has been extensively highlighted in coronary artery diseases. The aims within this study include the investigation of the molecular mechanism by which SIRT1 alleviates CAS. SIRT1 expression was first determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis in an endothelin-1 (ET-1)-induced rat CAS model. Interaction among SIRT1, nuclear factor-kappaB (NF-κB), myosin light chain kinase/myosin light chain-2 (MLCK/MLC2), and ET-1 was analyzed using luciferase reporter assay, RT-qPCR, and Western blot analysis. After ectopic expression and depletion experiments in vascular smooth muscle cells (VSMCs), contraction and proliferation of VSMCs and expression of contraction-related proteins (α-SMA, calponin, and SM22α) were measured by collagen gel contraction, 5-ethynyl-2'-deoxyuridine (EdU) assay, RT-qPCR, and Western blot analysis. The obtained results showed that SIRT1 expression was reduced in rat CAS models. However, overexpression of SIRT1 inhibited the contraction and proliferation of VSMCs in vitro. Mechanistic investigation indicated that SIRT1 inhibited NF-κB expression through deacetylation. Moreover, NF-κB could activate the MLCK/MLC2 pathway and upregulate ET-1 expression by binding to their promoter regions, thus inducing VSMC contraction and proliferation in vitro. In vivo experimental results also revealed that SIRT1 alleviated CAS through regulation of the NF-κB/MLCK/MLC2/ET-1 signaling axis. Collectively, our data suggested that SIRT1 could mediate the deacetylation of NF-κB, disrupt the MLCK/MLC2 pathway, and inhibit the expression of ET-1 to relieve CAS, providing a theoretical basis for the prospect of CAS treatment and prevention.NEW & NOTEWORTHY Rat coronary artery spasm models exhibit reduced expression of SIRT1. Overexpression of SIRT1 inhibits contraction and proliferation of VSMCs. SIRT1 inhibits NF-κB through deacetylation to modulate VSMC contraction and proliferation. NF-κB activates the MLCK/MLC2 pathway. NF-κB upregulates ET-1 to modulate VSMC contraction and proliferation.

t-Resveratrol Protects against Acute High Glucose Damage in Endothelial Cells

Postprandial hyperglycemia in diabetic and nondiabetic subjects is associated with endothelial dysfunction. Evidence shows that high glucose generates oxidative stress and a pro-inflammatory state promoting the development of cardiovascular diseases. trans-Resveratrol (t-RV) has been shown to reduce cardiovascular risk. To determine whether t-RV acts as a protector against acute high glucose (AHG)-induced damage, two in vitro models, rat aortic rings (RAR) and human umbilical vein endothelial cells (HUVEC) were used. RAR pretreated with AHG (25 mM D-glucose) for 3 h dramatically decreased the endothelium-dependent relaxation (EDR) induced by acetylcholine in phenylephrine (PE)-precontracted vessels. However, coincubation with t-RV significantly mitigated the damage induced by AHG on EDR. Pretreatment with AHG did not affect the vasodilation induced by sodium nitroprusside. HUVEC treated with t-RV decreased cytotoxicity and reduced radical oxygen species production induced by AHG. Taken together, these results suggest that t-RV can mitigate the AHG-induced EDR damage through a mechanism involving ROS scavenging and probably an increase in the bioavailability of NO.

The effects of resveratrol and exercise on age and gender-dependent alterations of vascular functions and biomarkers

The purpose of this study was to determine the effects of resveratrol and regular aerobic exercise on vascular functions and biomarkers related to vessel responsiveness in an age and gender-dependent manner. The study used young (3 months) and old (12 months) male and female Wistar albino rats. Resveratrol was given in the drinking water (0.05 mg/ml; approximately 7.5 mg/kg) for 6 weeks. In the exercise group, all rats performed treadmill running at 20 m/min on a 0° incline, 40 min/day, 3 times a week, for 6 weeks. Acetylcholine-induced, endothelium-dependent and sodium nitroprusside-mediated, endothelium-independent relaxations of rat thoracic aorta and blood levels of biomarkers were separately changed by resveratrol intake and exercise-training in an age and gender-dependent manner. Antioxidant enzymes and eNOS expressions in vessels were elevated by resveratrol and exercise. Resveratrol and exercise enhanced gene expressions of non-selective PDE1, 2, 3 and cAMP selective PDE4 but not cGMP selective PDE5 in the aorta. In addition, the aortic mRNA expression of inflammation markers were altered by resveratrol and exercise-training. The results of the study demonstrated that vessel responsiveness and biomarkers related to vascular functions were altered by resveratrol consumption and exercise-training in an age and gender-dependent manner.

Type of supplemented simple sugar, not merely calorie intake, determines adverse effects on metabolism and aortic function in female rats

High consumption of simple sugars causes adverse cardiometabolic effects. We investigated the mechanisms underlying the metabolic and vascular effects of glucose or fructose intake and determined whether these effects are exclusively related to increased calorie consumption. Female Sprague-Dawley rats were supplemented with 20% wt/vol glucose or fructose for 2 mo, and plasma analytes and aortic response to vasodilator and vasoconstrictor agents were determined. Expression of molecules associated with lipid metabolism, insulin signaling, and vascular response were evaluated in hepatic and/or aortic tissues. Caloric intake was increased in both sugar-supplemented groups vs. control and in glucose- vs. fructose-supplemented rats. Hepatic lipogenesis was induced in both groups. Plasma triglycerides were increased only in the fructose group, together with decreased expression of carnitine palmitoyltransferase-1A and increased microsomal triglyceride transfer protein expression in the liver. Plasma adiponectin and peroxisome proliferator-activated receptor (PPAR)-α expression was increased only by glucose supplementation. Insulin signaling in liver and aorta was impaired in both sugar-supplemented groups, but the effect was more pronounced in the fructose group. Fructose supplementation attenuated aortic relaxation response to a nitric oxide (NO) donor, whereas glucose potentiated it. Phenylephrine-induced maximal contractions were reduced in the glucose group, which could be related to increased endothelial NO synthase (eNOS) phosphorylation and subsequent elevated basal NO in the glucose group. In conclusion, despite higher caloric intake in glucose-supplemented rats, fructose caused worse metabolic and vascular responses. This may be because of the elevated adiponectin level and the subsequent enhancement of PPARα and eNOS phosphorylation in glucose-supplemented rats.

NEW & NOTEWORTHY

This is the first study comparing the effects of glucose and fructose consumption on metabolic factors and aortic function in female rats. Our results show that, although total caloric consumption was higher in glucose-supplemented rats, fructose ingestion had a greater impact in inducing metabolic and aortic dysfunction.

Resveratrol ameliorates lipid accumulation in HepG2 cells, associated with down-regulation of lipin1 expression

The pathogenesis of alcoholic fatty liver (AFL) disease is associated with the excessive accumulation of lipids in hepatocytes as well as oxidative stress. Resveratrol (RES), a dietary polyphenol found in red wine and grapes, has been shown to protect against AFL disease. However, the precise mechanisms that lead to this protective effect remain elusive. In this study, we used HepG2 cells to investigate the effects of RES on lipid metabolism and the mechanisms underlying these effects. HepG2 cells were cultured with oleic acid and alcohol for 48 h to induce excessive lipid accumulation. Oil red O staining showed that administration of oleic acid and alcohol induced more lipid accumulation than was observed in the control group, and that RES (15, 45, or 135 μmol/L) treatment reduced intracellular lipid droplets. RES treatment also significantly attenuated hepatic steatosis and lowered levels of intracellular triglycerides (TG). Western blot analysis showed that RES enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) and down-regulated the expression of sterol regulatory element-binding protein 1c (SREBP-1c) and lipin1. However, compound C, an AMPK inhibitor, reversed these effects of RES. In conclusion, RES reduced lipid accumulation and protected HepG2 cells. This effect may be associated with the down-regulation of SREBP-1c and lipin1 expression, increased levels of phosphorylated AMPK and ACC, and the activation of AMPK–lipin1 signaling.