Late-onset preeclampsia (LOPE) associates with reduced umbilical vein reactivity and endothelial nitric oxide synthase (eNOS) activity but increased human cationic amino acid (hCAT-1)–mediated L-arginine transport involving A_2A adenosine receptor in the fetoplacental unit. This study addresses the A_2B adenosine receptor (A_2BAR)-mediated response to insulin in the fetoplacental vasculature from LOPE. Umbilical veins and HUVECs were obtained from women with normal (n = 37) or LOPE (n = 35) pregnancies. Umbilical vein rings reactivity to insulin was assayed in the absence or presence of adenosine and MRS-1754 (A_2BAR antagonist) in a wire myograph. HUVECs were exposed to insulin, MRS-1754, BAY60–6583 (A_2BAR agonist), NECA (general adenosine receptors agonist) or N^G-nitro-L-arginine methyl ester (NOS inhibitor). A_2BAR, hCAT-1, total and phosphorylated eNOS, Akt and p44/42^mapk protein abundance were determined by Western blotting. Insulin receptors A (IR-A) and B (IR-B), eNOS and hCAT-1 mRNA were determined by qPCR. Firefly/Renilla luciferase assay was used to determine −1606 bp SLC7A1 (hCAT-1) promoter activity. L-Citrulline content was measured by HPLC, L-[³H]citrulline formation from L-[³H]arginine by the Citrulline assay, and intracellular cGMP by radioimmunoassay. LOPE-reduced dilation of vein rings to insulin was restored by MRS-1754. HUVECs from LOPE showed higher A_2BAR, hCAT-1, and IR-A expression, Akt and p44/42^mapk activation, and lower NOS activity. MRS-1754 reversed the LOPE effect on A_2BAR, hCAT-1, Akt, and eNOS inhibitory phosphorylation. Insulin reversed the LOPE effect on A_2BAR, IR-A and eNOS, but increased hCAT-1–mediated transport. Thus, LOPE alters endothelial function, causing an imbalance in the L-arginine/NO signalling pathway to reduce the umbilical vein dilation to insulin requiring A_2BAR activation in HUVECs.

迟发性子痫前期（LOPE）与脐静脉反应性降低和内皮型一氧化氮合酶（eNOS）活性相关，但与人类阳离子氨基酸（hCAT-1）介导的L-精氨酸转运有关，涉及胎盘素单位中的A _2A腺苷受体。这项研究解决了LOPE引起的胎盘胎脉系统中A _2B腺苷受体（A _2B AR）介导的对胰岛素的反应。脐静脉和HUVECs来自正常（n  = 37）或LOPE（n  = 35）怀孕的妇女。在不存在或存在腺苷和MRS-1754的情况下测定了脐静脉环对胰岛素的反应性（A _2B钢丝肌电图仪中的AR拮抗剂）。HUVEC暴露于胰岛素，MRS-1754，BAY60–6583（一种_2B AR激动剂），NECA（一种一般的腺苷受体激动剂）或N ^G-硝基-L-精氨酸甲酯（NOS抑制剂）。甲_2B AR，hCAT-1，总的和磷酸化的eNOS，Akt和P44 / 42 ^MAPK蛋白丰度通过蛋白质印迹确定。通过qPCR测定胰岛素受体A（IR-A）和B（IR-B），eNOS和hCAT-1 mRNA。使用萤火虫/海肾萤光素荧光素酶测定法测定-1606 bp SLC7A1（hCAT-1）启动子活性。L-瓜氨酸含量通过HPLC测量，通过L- [ ³ H]精氨酸从L- [ ³ H]精氨酸形成L- [ ³ H]瓜氨酸。瓜氨酸法和放射免疫法测定细胞内cGMP。MRS-1754恢复了LOPE减少的静脉环向胰岛素的扩张。来自LOPE的HUVEC显示较高的A _2B AR，hCAT-1和IR-A表达，Akt和p44 / 42 ^mapk活化，以及较低的NOS活性。MRS-1754逆转了LOPE对A _2B AR，hCAT-1，Akt和eNOS抑制性磷酸化的作用。胰岛素逆转了LOPE对A _2B AR，IR-A和eNOS的作用，但增加了hCAT-1介导的转运。因此，LOPE改变了内皮功能，导致L-精氨酸/ NO信号通路的失衡，从而减少了脐静脉扩张至需要HUVEC激活A _2B AR的胰岛素。