Dietary ellagic acid improves oxidant-induced endothelial dysfunction and atherosclerosis: Role of Nrf2 activation

Background

Oxidative stress-induced vascular endothelial cell injury is a major factor in the pathogenesis of atherosclerosis. Several evidences indicate that ellagic acid (EA), a phenolic compound, contributes to cardiovascular health. This study was to investigate the effects of EA on endothelial dysfunction and atherosclerosis via antioxidant-related mechanisms.

Methods

In animal studies, wild-type (WT) C57BL/6 mice and apolipoprotein E-deficient mice (ApoE^−/−) mice were fed: a high-fat (21%) diet (HFD) or a HFD plus with EA (HFD + EA), for 14 weeks. Vascular reactivity was studied in mice aortas. The effect of EA in human umbilical vein endothelial cells (HAECs) exposed to hypochlorous acid (HOCl) was also investigated.

Results

Compared with animals on HFD alone, EA attenuated atherosclerosis in WT mice. In aortic rings from two mice models, EA significantly improved endothelium-dependent relaxation and attenuated HOCl-induced endothelial dysfunction. Besides, EA significantly improved nitric oxide synthase activity, antioxidant capacity and markers of endothelial dysfunction in plasma. Western blot analysis showed that EA increased NF-E2-related factor 2 (Nrf2) and heme oxygenase-1(HO-1) expression in the aortas (P < 0.05). In a separate experiment, EA did not protect against HOCl-induced endothelial dysfunction in arteries obtained from Nrf2 gene knockout mice compared with WT mice. In HAECs, EA prevented HOCl-induced cellular damage and induced HO-1 protein expression, and these effects markedly abolished by the siRNA of Nrf2.

Conclusions

Our results provide further support for the protective effects of dietary EA particularly oxidant-induced endothelial dysfunction and atherosclerosis partly via Nrf2 activation.     

一氧化氮吸入联合高频震荡通气治疗新生儿严重呼吸衰竭的疗效分析

目的 探讨一氧化氮吸入(iNO)联合高频震荡通气(HFOV)治疗新生儿严重呼吸衰竭疗效。 方法 选取2013年3月至2016年3月60例HFOV中高参数设置下氧合差的患儿[吸入氧浓度(FIO₂)＞60%,经皮血氧饱和度(TcSO₂)＜80%],采用随机数字表法分为观察组及对照组,观察组予iNO联合HFOV治疗,对照组予单纯HFOV治疗,治疗中监测血气分析、血氧饱和度、血压、心率,监测血常规、出凝血时间、高铁血红蛋白等指标。比较两组的机械通气时间、救治成功率以及并发症发生率。 结果 iNO联合HFOV,能显著改善患儿氧合指数,使呼吸机参数逐渐下调至安全范围,且合理调整参数后患儿无明显不适,缩短患儿机械通气时间,提高呼吸衰竭患儿的抢救成功率。机械通气时间对照组为(107.00±39.60)h,观察组为(89.34±22.75)h,两组比较,差异有统计学意义(P＜0.05);死亡率对照组32.14%,观察组9.37%,两组比较,差异有统计学意义(P＜0.05)。观察组在未用iNO之前PH值、氧分压(PaO₂)、二氧化碳分压(PaCO₂)、动脉氧分压与吸入氧浓度比(PaO₂/FiO₂)、氧合指数(OI)值均差异无统计学意义(P＞0.05)。iNO后2 h、24 h比较差异有统计学意义(P＜0.05)。     

Beneficial effects of lifelong caloric restriction on endothelial function are greater in conduit arteries compared to cerebral resistance arteries

Endothelial dysfunction occurs in conduit and cerebral resistance arteries with advancing age. Lifelong caloric restriction (CR) can prevent the onset of age-related dysfunction in many tissues, but its effects on cerebral resistance artery function, as compared with conduit artery function, have not been determined. We measured endothelium-dependent dilation (EDD) in the carotid artery and middle cerebral artery (MCA) from young (5–7 months), old ad libitum fed (AL, 29–32 months), and old lifelong CR (CR, 40 % CR, 29–32 months) B6D2F1 mice. Compared with young, EDD for old AL was 24 % lower in the carotid and 47 % lower in the MCA (p < 0.05). For old CR, EDD was not different from young in the carotid artery (p > 0.05), but was 25 % lower than young in the MCA (p < 0.05). EDD was not different between groups after NO synthase inhibition with N^ω-nitro-l-arginine methyl ester in the carotid artery or MCA. Superoxide production by the carotid artery and MCA was greater in old AL compared with young and old CR (p < 0.05). In the carotid, incubation with the superoxide scavenger TEMPOL improved EDD for old AL (p > 0.05), with no effect in young or old CR (p > 0.05). In the MCA, incubation with TEMPOL or the NADPH oxidase inhibitor apocynin augmented EDD in old AL (p < 0.05), but reduced EDD in young and old CR (p < 0.05). Thus, age-related endothelial dysfunction is prevented by lifelong CR completely in conduit arteries, but only partially in cerebral resistance arteries. These benefits of lifelong CR on EDD result from lower oxidative stress and greater NO bioavailability.     

Mechanisms mediating the cardioprotective effect of carvedilol in cadmium induced cardiotoxicity. Role of eNOS and HO1/Nrf2 pathway

Cadmium (Cd) is a highly toxic heavy metal with several harmful effects including cardiotoxicity. For the first time, we aimed to evaluate the possible cardioprotective effect of carvedilol (CAR) in Cd induced cardiotoxicity and study the mechanisms involved in such protection including endothelial nitric oxide synthase (eNOS) and HO1/Nrf2 pathway. CAR (1,10 mg/kg/d) was administered orally for 4 weeks with Cd induced cardiac injury (3 mg/kg/d) orally for 4 weeks. We measured cardiac enzymes, mean arterial pressure changes, heme oxygenase-1 (HO1) and total antioxidant capacity (TAC). Moreover; cardiac tissue malondialdehyde (MDA), tumor necrosis factor alpha (TNFα), western blotting of caspase3 and eNOS levels and histopathology were evaluated. Immunoexpression of eNOS in cardiac tissue, gene expression changes of HO1, and nuclear factor erythroid 2-related factor 2 (Nrf2) using real time polymerase chain reactions (rtPCR) were detected. Our results showed that CAR could significantly decrease Cd induced cardiotoxicity.     

Effects of soluble copper and copper oxide nanoparticle exposure on the immune system of mussels,Mytilus galloprovincialis

Copper and copper oxide nanomaterials (nCuO) can enter the marine environment negatively impacting mussels, an environmental and commercially relevant organism. We analyzed the effects on the immune system of adult mussels exposed to soluble copper (CuSO₄, 20‐50 μg/L) or nCuO (100‐450 μg/L). CuSO₄ caused significant copper accumulation in gills and cell‐free hemolymph, while nCuO caused cell damage to gills and significant copper accumulation in hemocytes, the most abundant cells in the hemolymph. Both sources of copper caused cellular toxicity in hemocytes by increasing reactive oxygen species production and lysosome abundance, and decreasing multi‐drug resistance transporter activity. Though hemocyte abundance was not affected, their in‐vitro phagocytic activity decreased, explaining the slight (but not statistically significant) increase in bacterial proliferation in mussels exposed to the pathogenic bacteria Vibrio tubiashii following copper exposure. Thus, exposure to non‐lethal concentrations of CuSO₄ or nCuO can potentially increase mussel susceptibility to bacterial infections.     

High-content analysis for mitophagy response to nanoparticles: A potential sensitive biomarker for nanosafety assessment

Mitophagy, a selective autophagy of mitochondria, clears up damaged mitochondria to maintain cell homeostasis. We performed high-content analysis (HCA) to detect the increase of PINK1, an essential protein controlling mitophagy, in hepatic cells treated with several nanoparticles (NPs). PINK1 immunofluorescence-based HCA was more sensitive than assays and detections for cell viability and mitochondrial functions. Of which, superparamagnetic iron oxide (SPIO)-NPs or graphene oxide-quantum dots (GO-QDs) was selected as representatives for positive or negative inducer of mitophagy. SPIO-NPs, but not GO-QDs, activated PINK1-dependent mitophagy as demonstrated by recruitment of PARKIN to mitochondria and degradation of injured mitochondria. SPIO-NPs caused the loss of mitochondrial membrane potential, decrease in ATP, and increase in mitochondrial reactive oxide species and Ca²⁺. Blocking mitophagy with PARKIN siRNA aggravated the cytotoxicity of SPIO-NPs. Taken together, PINK1 immunofluorescence-based HCA is considered to be an early, sensitive, and reliable approach to evaluate the bioimpacts of NPs.     

洛伐他汀对醛固酮诱导鼠心肌成纤维细胞增殖及其 iNOS-NO 系统活性的调控作用

目的：探讨洛伐他汀对醛固酮诱导心肌成纤维细胞（ CFs）增殖及诱导型一氧化氮合酶-一氧化氮（ iN-OS-NO）系统活性的调控作用。方法用胰酶消化法分离、培养新生SD大鼠CFs,采用MTT比色法、硝酸还原酶法、分光光度法和半定量RT-PCR技术,观察不同浓度洛伐他汀对CFs增殖、NO含量、iNOS活性和iNOS mRNA表达的影响。结果洛伐他汀（1×10-8～1×10-5 mol/L）能剂量依赖性抑制醛固酮诱导CFs的增殖,升高CFs的NO含量、iNOS活性及增加iNOS mRNA的表达（P均＜0．05）,甲羟戊酸（1×10-3 mol/L）、法尼酯焦磷酸（5μmol/L）可完全逆转洛伐他汀的上调作用。洛伐他汀干预下醛固酮诱导CFs的NO生成量与iNOS活性、iNOS活性与iNOS mRNA表达均呈正相关（r分别为0．826、0．752,P均＜0．01）;CFs增殖数目与NO含量呈负相关（r＝-0．908,P＜0．01）。结论洛伐他汀可上调醛固酮诱导CFs的iNOS-NO系统活性,抑制CFs增殖,并呈剂量依赖性,其作用机制可能与甲羟戊酸途径调节有关。