An adequate placental vascularization allows the proper development of the fetus and it is crucial for the gestational success. A number of factors regulate angiogenesis, including vascular endothelial growth factor (VEGF), which induces the synthesis of nitric oxide (NO), a potent vasodilator produced by three different nitric oxide synthase (NOS) isoforms. NO is essential to maintain a low vascular resistance in the fetoplacental circulation, although at high concentrations, it may combine with excess superoxide to produce peroxynitrite, which reacts with proteins giving rise to nitrotyrosine. Since obesity, whose incidence is increasing worldwide, is characterized by a low-grade inflammatory state and increased levels of oxidative and nitrative stress, both affecting placental function, our aim was to evaluate the expression of VEGF, eNOS, and iNOS in full-term placentas obtained from normal weight and pre-pregnancy obese women by means of immunohistochemistry and real-time PCR. Moreover, we assessed the NO levels and the nitrotyrosine immunoexpression in the same sample groups. Our results show a significantly higher immunohistochemical expression of VEGF and eNOS in the endothelium of placentas from obese women than in controls, whereas the immunoexpression of iNOS was comparable in the two groups. These data agree with those of the gene expression analysis, thus suggesting the possible existence of a compensatory mechanism for changes in placental blood flow associated with obesity. As concerns nitrotyrosine and NO levels, we observed a significant increase in placental tissue from obese women which may contribute to the development of metabolic and cardiovascular diseases both in the mother and the offspring.

中文翻译：

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肥胖妇女足月胎盘中一氧化氮合酶和VEGF的表达

适当的胎盘血管形成可以使胎儿正确发育，这对妊娠成功至关重要。许多因素可调节血管生成，包括血管内皮生长因子（VEGF），可诱导一氧化氮（NO）的合成，一氧化氮是由三种不同的一氧化氮合酶（NOS）同工型产生的有效血管扩张剂。NO在维持胎盘胎盘循环中低血管阻力方面是必不可少的，尽管在高浓度下，NO可能与过量的超氧化物结合生成过氧亚硝酸盐，亚硝酸盐与蛋白质反应生成硝基酪氨酸。由于肥胖症的发病率在全球范围内呈上升趋势，其特征在于低度的炎症状态以及氧化和硝化应激水平升高，均影响胎盘功能，因此我们的目的是评估VEGF，eNOS，通过免疫组织化学和实时荧光定量PCR从正常体重和怀孕前肥胖妇女获得足月胎盘中的iNOS。此外，我们评估了同一样品组中的NO水平和硝基酪氨酸免疫表达。我们的结果表明，肥胖女性胎盘内皮中VEGF和eNOS的免疫组织化学表达明显高于对照组，而两组中iNOS的免疫表达相当。这些数据与基因表达分析的数据一致，因此表明可能存在与肥胖有关的胎盘血流变化的补偿机制。至于硝基酪氨酸和一氧化氮的含量，