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）的发生率为每1000例活产20至50例，估计至少影响美国所有新生儿的1% （www.cdc.gov）。FASD的病因尚不清楚，通常认为与神经元有关。事实上，母亲饮酒会导致神经元迁移、少突胶质细胞和小胶质细胞发育减少。然而，很少有人关注胎儿脑循环作为母亲饮酒的目标。胎儿脑血流对大脑发育中的氧气和营养物质的输送至关重要，脑动脉的血管反应是胎儿适应不良宫内环境的基础。动物模型实验表明，母体饮酒对胎儿脑动脉有血管扩张作用。这种作用的机制尚不清楚。内源性大麻素（eCBs: anandamide, 2-arachydonoylglycerol）在成人血液循环中是强大的血管扩张剂，我们的初步数据显示eCB受体CB1在胎儿血管中表达。因此，我们假设孕妇在妊娠后半期饮酒会通过eCB依赖机制改变胎儿脑动脉收缩能力。利用灵长类动物（狒狒，Papio spp.）妊娠模型，结合多普勒胎儿脑血流检查、稳定同位素稀释气相色谱/质谱法、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)确定妊娠后半期孕妇酗酒是否会改变胎儿脑动脉内源性大麻素系统的关键成分；各组血药浓度、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CB1受体的组织表达；2)在CB1受体拮抗剂、钙/电压门控钾（BK）和电压门控Ca2+通道阻滞剂存在的情况下，通过检测ecb诱导的受压胎儿脑动脉直径变化，确定母体酗酒是否改变了ecb介导的血管收缩性控制，并揭示潜在的亚细胞机制。我们的研究将首次确定胎儿大脑动脉eCB系统在胎儿循环对母亲饮酒的反应中的作用。建议研究的成功完成将为预防和治疗FASD开辟一个概念上的新领域。目前的工作也将高度相关，以代替快速增长的欧洲央行操纵治疗肥胖，心血管和神经系统疾病的领域，因为血管欧洲央行系统的药物改变可能会对胎儿大脑发育产生不利影响。

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.