High Density Lipoprotein (HDL) in Follicular Fluid and Fertility Outcomes

描述(由申请人提供)：有证据表明，卵泡内的高密度脂蛋白颗粒对女性生殖潜力有一定作用。卵泡液是揭示成熟卵母细胞微环境中代谢过程的生物学窗口。在体外受精(IVF)中识别预测早期胚胎发育结局参数的高密度脂蛋白生物标志物将有助于更好地了解调控卵母细胞能力的因素。这一知识的获得将有助于进一步研究了解人类卵泡内卵母细胞发育的遗传和环境调节。高密度脂蛋白(高密度脂蛋白)是唯一存在于FF中的脂蛋白。高密度脂蛋白的胆固醇转运、抗氧化和抗炎活性取决于高密度脂蛋白颗粒的动态分布和复杂的高密度脂蛋白组成，包括脂类、载脂蛋白、微量营养素和酶。在初步研究中，我们已经确定，高密度脂蛋白胆固醇和载脂蛋白AI(Apo-AI)浓度是体外受精过程中有害胚胎碎裂的显著负面预测因子。此外，我们还证实了血清和FF高密度脂蛋白磷脂：胆固醇摩尔比(反映高密度脂蛋白颗粒大小和亚类分布)与胚胎碎裂呈正相关。我们还通过核磁共振谱和高密度脂蛋白亚类的分离和分析直接证明了相对于血清，FF-高密度脂蛋白颗粒的大小分布和脂质组成发生了变化。高密度脂蛋白相关的人血清对氧磷酶1(PON1)活性的存在也是最初被描述的。将招募180名接受试管受精的预期队列女性。IVF治疗期间将采集卵泡液、颗粒细胞和外周血。将用核磁共振光谱仪测定血清和FF-高密度脂蛋白的颗粒大小，并分离出高密度脂蛋白亚类(HDL2和HDL3)，并评估它们的相关脂质、载脂蛋白、脂溶微量营养素成分和PON1活性。所有测量将与胚胎形态参数(卵母细胞完整性的替代标记物)相关。每个HDL2或HDL3颗粒的高密度脂蛋白亚类成分的归一化将被用来表征相对于血清高密度脂蛋白的独特颗粒组成，并识别可能解释我们关于胚胎质量参数的初步观察的特定差异。我们还将检测从有/无碎裂的胚胎中获得的GC的脂蛋白信号和胆固醇代谢相关基因的表达，以确定胆固醇代谢基因的差异。除了作为了解人类卵泡代谢状态的窗口的重要性外，FF还是研究高密度脂蛋白介导的胆固醇在缺乏其他脂蛋白的生理系统中的代谢和运输机制的优秀模型系统。了解高密度脂蛋白在卵泡发育过程中的变化如何导致其功能失调，将有助于更深入地了解高密度脂蛋白在人类卵母细胞和胚胎发育潜力中的作用。 公共卫生相关性：本研究提案中详细介绍的工作侧重于更好地定义与高密度脂蛋白颗粒代谢有关的人类卵泡的生理学，这可能影响人类卵母细胞和胚胎的发育潜力。随着孕妇年龄的增加，生育选择的社会困境导致了不孕，而且越来越多的证据表明，环境暴露会影响生殖生理的各个方面，因此有必要对高密度脂蛋白在人类卵巢卵泡和内卵母细胞的健康中所起的作用有更深入的了解。

DESCRIPTION (provided by applicant): There is evidence that high density lipoprotein particles within the ovarian follicle play a role in female reproductive potential. Follicular fluid (FF) is a biological window which can reveal the metabolic processes occurring in the microenvironment of the maturing oocyte. Identification of HDL biomarkers in FF that predict early embryo development outcome parameters would enable a greater understanding of the factors that regulate oocyte competence during in vitro fertilization (IVF). This gain of knowledge would allow for further research development in the understanding of the genetic and environmental regulation of oocyte development within the human follicle. High density lipoprotein (HDL) is the sole lipoprotein present in FF. The cholesterol transport, anti-oxidant and anti-inflammatory activities of HDL are a function of the dynamic HDL particle size distributions and the complex HDL composition which includes lipids, apolipoproteins, micronutrients and enzymes. In pilot studies, we have established that HDL cholesterol and apolipoprotein AI (Apo-AI) concentrations, reflecting total HDL concentration within FF, are significant negative predictors of detrimental embryo fragmentation during IVF. Furthermore, we have established that serum and FF HDL phospholipid: cholesterol molar ratios (reflecting HDL particle size and subclass distribution) are positively correlated with embryo fragmentation. We have also directly demonstrated by NMR spectrometry and HDL subclass isolation and analysis that FF-HDL particles have an altered size distribution and lipid composition relative to serum. The presence of HDL-associated human serum paraoxonase 1 (PON1) activities in FF has also been originally described. A prospective cohort of 180 women undergoing IVF will be recruited. Follicular fluid, granulosa cells and peripheral blood will be collected during IVF treatment. Serum and FF-HDL particle size will be determined by NMR spectrometry and HDL subclass (HDL2 and HDL3) will be isolated and their associated lipid, apolipoprotein, fat-soluble micronutrient compositions, and PON1 activities will be assessed. All measurements will be correlated with embryo morphology parameters (surrogate markers of oocyte integrity). Normalization of HDL subclass components per HDL2 or HDL3 particle will be used to characterize the unique particle composition of FF-HDL relative to serum HDL and identify the specific differences which may account for our pilot observations with regard to embryo quality parameters. We will also examine the lipoprotein signaling and cholesterol metabolism-related gene expression from GCs obtained from embryos with/without fragmentation to identify differences in cholesterol metabolism genes. Aside from its importance as a window into the metabolic state of the human ovarian follicle, FF represents an excellent model system for studying HDL-mediated cholesterol metabolism and transport mechanisms in a physiologic system devoid of other lipoproteins. Understanding how modifications of HDL within FF render it dysfunctional would add greater depth of understanding to the role of HDL in the developmental potential of the human oocyte and embryo. PUBLIC HEALTH RELEVANCE: The work detailed in this study proposal focuses on better defining the physiology of the human ovarian follicle with respect to HDL particle metabolism that may influence the developmental potential of the human oocyte and embryo. Given the societal dilemma of reproductive choice with advanced maternal age resulting in the infertile condition together with the increasing evidence that environmental exposures influence various aspects of reproductive physiology, it is imperative to develop a greater understanding of the role that HDL plays in the health of the human ovarian follicle and the oocyte within.