Fetal cerebrovascular eCB system as a target of maternal alcohol consumption

描述（由申请人提供）：在一项全球学龄儿童研究中，胎儿酒精谱系障碍（FASD）的发生率范围为每1,000例活产20 - 50例，估计影响美国所有出生婴儿的至少1%（www.cdc.gov）。FASD的病因学知之甚少，通常被认为是神经源性的。事实上，母亲饮酒导致神经元迁移、寡腺细胞和小胶质细胞发育减少。然而，很少有人注意到胎儿脑循环作为母亲饮酒的目标。胎儿脑血流对于向发育中的脑输送氧气和营养物是至关重要的，并且脑动脉的血管反应是胎儿适应不利的宫内条件的基础。动物模型的实验工作表明，母亲饮酒对胎儿脑动脉有舒张作用。该效应的机制仍未知。内源性大麻素（eCB：花生四烯酸（anandamide）、2-花生四烯酸甘油（2-arachydonoylglycerol）在成人循环中是强有力的血管扩张剂，并且我们的初步数据显示eCB受体CB 1在胎儿血管中表达。因此，我们假设母亲在妊娠后半期饮酒通过eCB依赖性机制改变胎儿脑动脉收缩力。使用灵长类动物模型（狒狒，Papio spp.）结合胎儿脑血流的多普勒检查、稳定同位素稀释气相色谱/质谱、免疫组织化学、RT-PCR、加压脑动脉直径测量和选择性药理学，我们将：1）确定妊娠后半期母亲狂饮是否改变胎儿脑动脉中内源性大麻素系统的关键要素：anandamide和2- arachydonoylglycerol的循环水平，其代谢酶脂肪酸酰胺水解酶（FAAH）和单酰基甘油脂肪酶（MAGL）的组织表达，以及eCB的CB 1受体的组织表达; 2）确定母亲酗酒是否改变eCB介导的血管收缩性控制，并通过测试eCB-1来揭示潜在的亚细胞机制。在CB 1受体拮抗剂、钙/电压门控钾（BK）和电压门控钙通道阻滞剂存在下，诱导加压胎脑动脉直径变化。我们的研究将首次建立胎儿脑动脉eCB系统在胎儿循环对母亲饮酒的反应中的作用。成功完成拟议的研究将为预防和治疗FASD开辟概念上的新途径。目前的工作也将是高度相关的替代快速增长的领域的eCB操纵治疗肥胖症，心血管和神经系统疾病，血管eCB系统的药物改变可能会导致胎儿大脑发育的不利影响。

DESCRIPTION (provided by applicant): The incidence of fetal alcohol spectrum disorders (FASD) ranges from 20 to 50 per 1,000 live births in a worldwide studies of school-age children and is estimated to affect at least 1% of all births in the US (www.cdc.gov). The etiology of FASD is poorly understood, and is usually considered to have neuronal origin. Indeed, maternal alcohol consumption results in diminished neuronal migration, oligodenrocytes and microglial development. However, little attention is given to fetal cerebral circulation as a target of maternal drinking. Fetal cerebral blood flow is critical for oxygen and nutrient delivery to developing brain and vascular responses of cerebral arteries are fundamental in the fetal adaptation to the adverse intrauterine conditions. The experimental work in animal models showed vasodilating effect of maternal alcohol consumption in fetal cerebral arteries. The mechanism(s) of this effect remains unknown. Endocannabinoids (eCBs: anandamide, 2-arachydonoylglycerol) are powerful vasodilators in adult circulation, and our preliminary data show expression of eCB receptor CB1 in fetal blood vessels. Therefore, we hypothesize that maternal alcohol consumption during second half of gestation alters fetal cerebral artery contractility via eCB dependent mechanism(s). Using a primate model (baboon, Papio spp.) of pregnancy and combining Doppler examination of fetal cerebral blood flow, stable isotope dilution gas chromatography/mass spectrometry, immunohistochemistry, RT-PCR, pressurized cerebral artery diameter measurements and selective pharmacology, we will: 1) Establish whether maternal binge drinking during the second half of gestation alters key elements of the endocannabinoid system in fetal cerebral arteries: circulating level of anandamide and 2- arachydonoylglycerol, tissue expression of their metabolizing enzymes fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), respectively, and tissue expression of CB1 receptor for eCBs; 2) Determine whether maternal binge drinking alters eCB-mediated control of vascular contractility and unveil underlying subcellular mechanism(s) by testing eCB-induced pressurized fetal cerebral artery diameter change in the presence of CB1 receptor antagonist, calcium/voltage-gated potassium (BK) and voltage-gated Ca2+ channel blockers. Our study will establish for the first time role of fetal cerebral artery eCB system in the respons of fetal circulation to maternal alcohol consumption. Successful completion of the proposed studies will open conceptually new venue for the prevention and treatment of FASD. Current work will be also highly relevant in the lieu of rapidly growing area of eCB manipulation for treatment of obesity, cardiovascular and neurological disorders, as pharmaceutical alteration of vascular eCB system may cause adverse effects on fetal brain development.