Fetal cerebrovascular eCB system as a target of maternal alcohol consumption

描述(由申请人提供)：在一项针对学龄儿童的全球研究中，胎儿酒精谱系障碍(FASD)的发病率从每1000名活产儿中有20人到50人不等，估计影响到美国至少1%的新生儿(www.cdc.gov)。FASD的病因目前知之甚少，通常被认为是神经源性的。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，作为母亲饮酒目标的胎儿脑循环却很少受到关注。胎儿的脑血流量是向发育中的大脑输送氧气和营养物质的关键，而脑血管的反应是胎儿适应不利宫内环境的基础。在动物模型上的实验工作显示了母亲饮酒对胎儿大脑动脉的血管扩张作用。这种效应的机制(S)尚不清楚。内源性大麻素(ECB：anandide，2-arachydonoyl甘油)是成人循环中强有力的血管扩张剂，我们的初步数据表明，ECB受体CB1在胎儿血管中表达。因此，我们假设孕中期母亲饮酒通过ECB依赖机制改变胎儿大脑动脉收缩功能(S)。使用灵长类动物模型(狒狒，Papio spp.)结合妊娠中期胎儿脑血流的多普勒检测、稳定同位素稀释气相色谱/质谱仪、免疫组织化学、RT-PCR、加压脑动脉内径测量和选择性药理学，我们将：1)确定妊娠后半期母亲酗酒是否改变了胎儿大脑动脉内大麻系统的关键要素：环胺和2-阿拉伯糖酰甘油的循环水平，其代谢酶脂肪酸酰胺水解酶(FAAH)和单酰甘油酶(MAGL)的组织表达，以及CB1受体的组织表达；2)通过检测CB1受体拮抗剂、钙/电压门控钾(BK)和电压门控钙通道阻滞剂对ECB诱导的加压胎儿脑动脉内径的改变，确定母亲酗酒是否改变了ECB介导的血管收缩控制，并揭示了潜在的亚细胞机制(S)。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反应中的作用。拟议研究的成功完成将为预防和治疗FASD开辟概念上的新场所。目前的工作也将在替代快速增长的ECB操作领域用于治疗肥胖、心血管和神经疾病方面具有高度相关性，因为对血管ECB系统的药物改变可能会对胎儿大脑发育造成不利影响。

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.