In Utero Programming of Adult Vascular Function

不利的胎儿环境和成人疾病之间的相关性可能会被特定疾病（如血管疾病）的遗传易感性所混淆，因为传递给胎儿的母体基因也可能决定子宫环境。流行病学研究可能无法区分不利的子宫环境与母亲和胎儿共同的遗传易感性。由于内皮型一氧化氮合酶（NOS 3）在决定成人血管功能方面非常重要，其功能缺陷会导致妊娠期异常血管适应和不利的胎儿环境，我们将缺乏功能性NOS 3基因的转基因小鼠（NOS 3-/-KO）与其野生型对照（NOS 3 +/+WT）杂交，以阐明胎儿环境与遗传在决定成人血管功能方面的作用。我们的初步结果表明，从父亲遗传功能性NOS 3等位基因并因此在NOS 3-/-KO母亲（NOS 3 +Pat/-Mat）中发育的杂合成年小鼠中的血管表型与NOS 3-/-KO小鼠相似。相比之下，遗传父亲的非功能性NOS 3等位基因并在NOS 3 +/+WT母亲（NOS 3 +Mat/-Pat）中发育的杂合成人中的血管表型与NOS 3 +/+WT小鼠相似。我们假设，杂合子小鼠之间观察到的差异是由于胎儿编程所造成的不利的子宫环境，导致在NOS 3-/-KO妊娠继发于缺乏NOS 3功能的血管适应性改变。为了检验这一假设，我们提出了以下目的：1）确定由NOS 3-/-KO雌性与NOS 3-/-KO或NOS 3 +/+WT雄性交配所生的成年后代的血管功能和血压，并将它们与NOS 3 +/+WT雌性与NOS 3-/-KO或NOS 3 +/+WT雄性交配所生的后代进行比较; 2）通过比较NOS 3-+Pat/-Mat、NOS 3 +Mat/-Pat、将NOS 3-/-KO和NOS 3 +/+WT胚胎转移到NOS 3-/-KO代孕母亲中，与转移到NOS 3 +/+WT代孕母亲中的胚胎进行比较; 3）通过检查NOS 3 +Pat/-Mat，NOS 3 +Mat/-Pat，4）比较在第1次、第2次和第5次妊娠中由相同母鼠生育的N 0 S3 +Pat/-Mat、N 0 S3 +Mat/-Pat、N 0 S3-/-KO和N 0 S3 +/+WT后代之间的成年血管表型：这种独特的模型与异常子宫环境相关的不良妊娠结局有关，如先兆子痫和胎儿生长受限，并对后代的长期健康具有重要意义。

The reported association between an unfavorable fetal environment and adult diseases may be confounded by a genetic predisposition toward specific diseases (eg, vascular diseases) as the maternal genes that are transmitted o the fetus may also set the uterine environment. Epidemiological studies may not differentiate between the unfavorable uterine environment vs the hereditary predisposition common to mother and fetus. As endothelial nitric oxide synthase (NOS3) is important in determining vascular function in adults, and deficiency in its function leads to abnormal vascular adaptations in pregnancy and an unfavorable fetal environment, we crossbred transgenic mice lacking a functional NOS3 gene (NOS3-/-KO) and their wild-type control (NOS3+/+WT) to clarify the roles of the fetal environment vs genetics in determining adult vascular function. Our preliminary results show that the vascular phenotype in heterozygous adult that inherit the functional NOS3 allele from the father and therefore develop in NOS3-/-KO mothers (NOS3+Pat/-Mat) is similar to NOS3-/-KO mice. In contrast, the vascular phenotype in heterozygous adults that inherit the father's nonfunctional NOS3 allele and develop in NOS3+/+WT mothers (NOS3+Mat/-Pat) is similar to NOS3+/+WT mice. We hypothesize that the observed difference between the heterozygous mice is due to fetal programming caused by an unfavorable uterine environment resulting from altered vascular adaptations in the NOS3-/-KO pregnancy secondary to lack of NOS3 function. To test this hypothesis, we propose the following aims: 1) determine vascular function and blood pressure in adult offspring born to NOS3-/-KO females bred with NOS3-/-KO or NOS3+/+WT males, and compare them to offspring of NOS3+/+WT females bred with NOS3-/-KO or NOS3+/+WT males; 2) determine the roles of uterine environment vs genetics by comparing the vascular phenotype in later life in NOS3-+Pat/-Mat, NOS3+Mat/-Pat, NOS3-/-KO and NOS3+/+WT embryos transferred into NOS3-/-KO surrogate mothers to those transferred into NOS3+/+WT surrogate mothers; 3) determine the transgenerational consequences of fetal programming by examining the vascular phenotype in NOS3+Pat/-Mat, NOS3+Mat/-Pat, NOS3-/-KO and NOS3+/+WT during pregnancy (aim 3a), as well as in their offspring in adult life (aim 3b); 4) compare adult vascular phenotype between NOS3+Pat/-Mat , NOS3+Mat/-Pat, NOS3-/-KO and NOS3+/+WT offspring born to the same dams in the 1st, 2nd, and 5th pregnancies: This unique model is relevant to adverse pregnancy outcomes related to abnormal uterine environment, such as preeclampsia and fetal growth restriction, and has significant implications regarding the long-term health of offspring.