叶黄素对大鼠视网膜蓝光损伤防护作用机制研究

目的探讨叶黄素防护视网膜蓝光损伤的相关机制。方法将大鼠按体重随机分为6组:正常对照组、模型对照组、溶剂对照组以及叶黄素低、中、高剂量组。叶黄素低、中、高剂量组分别注射0.5、1.0和2.0mg/ml的叶黄素,溶剂对照组注射由生理盐水和Tween80以9:1混合的溶剂,注射剂量均为5μl。暗适应24h,利用蓝光光损伤仪建立大鼠视网膜光损伤模型,光暴露时间为2h。光暴露结束后暗适应72h,处死取视网膜测定氧化应激指标、神经元型一氧化氮合酶(nNOS)和c-fos蛋白的表达情况。结果与模型对照组及溶剂对照组相比,叶黄素剂量组大鼠视网膜中丙二醛(MDA)含量显著减少(P<0.05),而SOD和GSH-Px的活性在各组间差异无显著性。叶黄素剂量组大鼠视网膜中c-fos蛋白的表达量低于溶剂对照组和模型对照组(P<0.05),而nNOS的表达量与其他组相比差异无显著性(P>0.05)。结论叶黄素可能通过淬灭氧自由基,抑制脂质过氧化和c-fos基因的表达发挥其保护作用。     

Photoprotection by pistachio bioactives in a 3-dimensional human skin equivalent tissue model

Reactive oxygen species (ROS) generated during ultraviolet (UV) light exposure can induce skin damage and aging. Antioxidants can provide protection against oxidative injury to skin via “quenching” ROS. Using a validated 3-dimensional (3D) human skin equivalent (HSE) tissue model that closely mimics human skin, we examined whether pistachio antioxidants could protect HSE against UVA-induced damage. Lutein and γ-tocopherol are the predominant lipophilic antioxidants in pistachios; treatment with these compounds prior to UVA exposure protected against morphological changes to the epithelial and connective tissue compartments of HSE. Pistachio antioxidants preserved overall skin thickness and organization, as well as fibroblast morphology, in HSE exposed to UVA irradiation. However, this protection was not substantiated by the analysis of the proliferation of keratinocytes and apoptosis of fibroblasts. Additional studies are warranted to elucidate the basis of these discordant results and extend research into the potential role of pistachio bioactives promoting skin health.     

Development and characterization of lutein-loaded SNEDDS for enhanced absorption in Caco-2 cells

Abstract

A self-nanoemulsifying drug delivery system (SNEDDS) has been developed for enhanced oral bioavailability of lutein. Its permeation enhancement has been evaluated using monolayers of Caco-2 cells. SNEDDS is composed of a mixture of Lexol® and Emulmetik® 900, Labrasol®, and Tween 80 as oil, surfactant and co-surfactant, respectively. Upon dilution of lutein-loaded SNEDDS with water, a nanoemulsion was obtained in <10?s with spherical droplets of 40–150?nm in diameter. The zeta potential was in the range of ?19 to ?32?mV. Increasing the ratio of surfactant to co-surfactant decreased the mean droplet size. Dissolution studies showed that lutein was released rapidly (<5?min) from SNEDDS into 0.1?N HCl and pH 6.8 phosphate buffer solution without any aggregation. In vitro studies using Caco-2 cells revealed that lutein-loaded SNEDDS showed shorter lag time and greater (2-fold) cellular accumulation compared with the lutein dispersion.     

叶黄素干预对早期老年黄斑变性患者生活质量的影响

目的研究叶黄素干预对早期老年黄斑变性(aged-related macular degeneration,AMD)患者生活质量的影响。方法采用随机双盲空白对照法,将108名早期AMD患者随机分为叶黄素低剂量组、叶黄素高剂量组、叶黄素/玉米黄素混合干预组和安慰剂对照组,连续服药48 w。于服药0 w及48 w,进行一般情况、膳食营养摄入状况、最佳矫正视力和视功能相关生存质量测定。结果早期AMD患者整体健康状况、总体视力及近距离活动能力显著下降,且总体视力、近距离活动能力分别与矫正视力呈显著正相关。服用叶黄素后最佳矫正视力和视力得分较用药前呈上升趋势;叶黄素/玉米黄素混合用药组近距离活动能力得分较服药前显著提高(P<0.05)。基线视力、活动受限程度分别与其在用药期间的改变呈负相关。结论叶黄素干预可提高早期AMD患者视力水平,并显著改善其近距离活动能力,提示叶黄素对早期AMD患者生活质量具有一定的保护作用。[营养学报,2012,34(4):327-331]     

叶黄素、大豆甙元及卵磷脂对小鼠认知行为影响

目的研究叶黄素、大豆甙元、卵磷脂对小鼠认知行为的影响。方法各组经灌胃持续给药6周,采用跳台和Morris水迷宫对小鼠进行行为学测试,取小鼠血清及脑组织进行生化检测。结果大豆甙元组、卵磷脂组、混合组脑丙二醛(MDA)含量分别为(3.4±0.4)、(3.4±0.4)、(3.2±0.3)nmol/(mg.prot);明显低于空白对照组的(3.8±0.5)nmol/(mg.prot)(P<0.05,P<0.01);叶黄素组、大豆甙元组、混合组及阳性对照组Morris逃避潜伏期分别为(23.09±6.59)、(22.29±7.33)、(21.45±5.45)、(17.54±6.65)s,明显低于空白对照组的(45.80±9.70)s(P<0.05,P<0.05);叶黄素组、大豆甙元组、卵磷脂组、混合组脑5-羟色胺(5-HT)含量分别为(210.08±20.46)、(222.95±15.87)、(225.18±24.56)、(237.97±29.30)ng/mL,明显高于空白对照组的(171.61±32.94)ng/mL(P<0.01),叶黄素、卵磷脂、混合组脑去甲肾上腺素(NE)含量分别为(104.09±7.63)、(...     

年龄相关性黄斑变性与生活方式危险因素的关系

目的:探讨年龄相关性黄斑变性(age-related macular degeneration,AMD)与饮食、生活方式中危险因素的关系。方法:年龄大于60岁眼病患者589例中筛选出48例AMD患者,从是否患高血压和糖尿病、是否患白内障和糖尿病视网膜病变、体重指数、是否吸烟和喝酒、饮食中是否摄入叶黄素/玉米黄素和β-胡萝卜素等方面进行问卷调查。结果:糖尿病、糖尿病视网膜病变、体重指数、吸烟、喝酒是AMD的危险因素,差别有统计学意义(P<0.05)。饮食中类胡萝卜素类的摄入能够减少AMD的发生,差别有统计学意义(P<0.05)。结论:停止吸烟和喝酒、增加类胡萝卜素的摄入能够减少AMD的发生。     

Quantification of reduced macular pigment optical density in the central retina in macular telangiectasia type 2

Recently, a unique distribution, namely a reduction of macular pigment optical density (MPOD) within the central retina with a surrounding ring-like structure of preserved MPOD at about 6 degrees eccentricity was suggested to be a common finding in macular telangiectasia (MacTel) type 2. In order to quantify this reduced MPOD, 28 eyes of 14 patients with MacTel type 2 were investigated by fundus reflectometry and two wavelengths fundus autofluorescence (FAF; at 488 nm and 514 nm). Fundus reflectometry showed a reduced MPOD within the central 4 degrees eccentricity that was most absent temporal to the foveola. At 6 degrees, MP density was not different from normative values. Two wavelengths FAF was in accordance with these findings. Fundus reflectometry also allowed separate determination of lutein and zeaxanthin. The patients with MacTel type 2 showed a disproportionally high zeaxanthin reduction. The study suggests that in MacTel type 2, there might be an inability to accumulate MP in the central retina. This disease might serve as a model to further study abnormalities of MP distribution in retinal disorders and to elucidate the mechanisms of MP deposition in the retina.     

The role of macular pigment assessment in clinical practice: a review

This review compares the results of studies that have investigated the impact of lutein and zeaxanthin supplementation on macular pigment optical density (MPOD) with those that have investigated the reliability of techniques used to measure macular pigment optical density. The review will focus on studies that have used heterochromatic flicker photometry for measurement of macular pigment optical density, as this is the only technique that is currently available commercially to clinicians. We identified articles that reported on supplementation with lutein and/or zeaxanthin and/or meso‐zeaxanthin on macular pigment optical density measurement techniques published in peer‐reviewed journals, through a multi‐staged, systematic approach. Twenty‐four studies have investigated the repeatability of MPOD measurements using heterochromatic flicker photometry. Of these, 10 studies provided a coefficient of repeatability or data from which the coefficient could be calculated, with a range in values of 0.06 to 0.58. The lowest coefficient of repeatability assessed on naïve subjects alone was 0.08. These values tell us that, at best, changes greater than 0.08 can be considered clinically significant and at worst, only changes greater than 0.58 can be considered clinically significant. Six studies assessed the effect of supplementation with up to 20 mg/day lutein on macular pigment optical density measured using heterochromatic flicker photometry and the mean increase in macular pigment optical density ranged from 0.025 to 0.09. It seems reasonable to conclude that the chance of eliciting an increase in macular pigment optical density during six months of daily supplementation with between 10 and 20 mg lutein that is of sufficient magnitude to be detected by using heterochromatic flicker photometry on an individual basis is small. Commercially available heterochromatic flicker photometers for macular pigment optical density assessment in the clinical environment appear to demonstrate particularly poor coefficient of repeatability values. Clinicians should exercise caution when considering the purchase of these instruments for potential monitoring of macular pigment optical density in response to supplementation in individual patients.     

A Systematic Review of Carotenoids in the Management of Diabetic Retinopathy

Diabetic retinopathy, which was primarily regarded as a microvascular disease, is the leading cause of irreversible blindness worldwide. With obesity at epidemic proportions, diabetes-related ocular problems are exponentially increasing in the developed world. Oxidative stress due to hyperglycemic states and its associated inflammation is one of the pathological mechanisms which leads to depletion of endogenous antioxidants in retina in a diabetic patient. This contributes to a cascade of events that finally leads to retinal neurodegeneration and irreversible vision loss. The xanthophylls lutein and zeaxanthin are known to promote retinal health, improve visual function in retinal diseases such as age-related macular degeneration that has oxidative damage central in its etiopathogenesis. Thus, it can be hypothesized that dietary supplements with xanthophylls that are potent antioxidants may regenerate the compromised antioxidant capacity as a consequence of the diabetic state, therefore ultimately promoting retinal health and visual improvement. We performed a comprehensive literature review of the National Library of Medicine and Web of Science databases, resulting in 341 publications meeting search criteria, of which, 18 were found eligible for inclusion in this review. Lutein and zeaxanthin demonstrated significant protection against capillary cell degeneration and hyperglycemia-induced changes in retinal vasculature. Observational studies indicate that depletion of xanthophyll carotenoids in the macula may represent a novel feature of DR, specifically in patients with type 2 or poorly managed type 1 diabetes. Meanwhile, early interventional trials with dietary carotenoid supplementation show promise in improving their levels in serum and macular pigments concomitant with benefits in visual performance. These findings provide a strong molecular basis and a line of evidence that suggests carotenoid vitamin therapy may offer enhanced neuroprotective effects with therapeutic potential to function as an adjunct nutraceutical strategy for management of diabetic retinopathy.     

Carotenoid lutein protects rats from paracetamol‐, carbon tetrachloride‐ and ethanol‐induced hepatic damage

Objectives Carotenoids are a class of natural fat‐soluble pigments that are found in many fruits and vegetables. Consumption of a diet rich in carotenoids has been epidemiologically correlated with a lower risk for several diseases. In the present study the carotenoid lutein (3,3′‐dihydroxy‐β,ε‐carotene) was evaluated for its hepatoprotective activity in rats. Methods Paracetamol, 20% ethanol and carbon tetrachloride were used to induce liver toxicity. Key findings Levels of serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase and alkaline phosphatases, which were increased in the serum, were found to be significantly reduced by the treatment of lutein in a dose‐dependent manner, indicating that lutein may reduce the hepatotoxicity induced by these agents_. Serum bilirubin was also significantly lower in lutein‐treated groups compared with control. Increased lipid peroxidation, conjugated diene and hydroperoxides in the liver tissue produced by the administration of paracetamol were found to be reduced in the lutein‐treated groups. Levels of antioxidant enzymes, like superoxide dismutase, catalase, glutathione peroxidase and glutathione, were found to be increased in lutein‐treated groups compared with control group during alcohol‐ and CCl₄‐induced liver toxicity. Hydroxyproline, which is an indicator of fibrosis in liver tissue, was high in the ethanol‐treated control group. Hydroxyproline levels were decreased by simultaneous lutein administration. Conclusions Histopathological evidence confirmed the protection offered by lutein from the tissue damage caused by hepatotoxins. The hepatoprotective action may be due to lutein's ability to scavenge reactive oxygen radicals.