Very Low Density Lipoprotein and Low Density Lipoprotein Receptor mRNA Expression in Placentae from Preeclamptic Pregnancies and Fetal Growth Restriction

甘油三酯(TG)在胎盘中的转运和代谢途径尚未得到详细研究。本研究对妊娠期糖尿病(GDM)合并子痫前期患者的血脂特点及胎盘系统脂代谢进行了研究。本研究特别检测了极低密度脂蛋白(VLDL)受体和低密度脂蛋白(LDL)受体mRNA在胎盘中的表达，旨在阐明这些mRNA的表达与胎盘病理的关系。在我科分娩的产妇(正常孕妇及有并发症的产妇)均征得知情同意。测定血清脂质和脂蛋白水平。另外，取自人胎盘的绒毛组织，作为后续实验的材料。用琼脂糖凝胶电泳法提取RNA，进行Northern杂交。为了比较基因表达的相对数量，…基因表达的条带对更多的SSION进行扫描和定量。子痫前期组和妊娠期糖尿病组分娩时的甘油三酯、极低密度脂蛋白水平显著高于正常妊娠组。妊娠期糖尿病组极低密度脂蛋白受体基因表达显著高于正常对照组，子痫前期组显著低于正常对照组。正常对照组、妊娠期糖尿病组和子痫前期组低密度脂蛋白受体基因表达差异无统计学意义。在所有妊娠组中，极低密度脂蛋白受体mRNA的表达与脐血中甘油三酯或极低密度脂蛋白水平呈正相关。在GDM组中，3例出生体重超过3500g的新生儿脐血中TG和VLDL浓度较高。产后1个月时，子痫前期组和妊娠期糖尿病组血糖虽已恢复正常，但血清甘油三酯和极低密度脂蛋白水平仍处于较高水平，高密度脂蛋白胆固醇水平明显降低。本研究首次证实，与正常孕妇相比，子痫前期和妊娠期糖尿病患者存在(1)血中血脂，尤其是作为胎盘能量来源的甘油三酯过多。(2)胎盘极低密度脂蛋白受体基因表达上调，(3)脐血中甘油三酯和极低密度脂蛋白水平升高，(4)产后1个月仍有高脂血症。其原因推测如下。甘油三酯是补偿胰岛素抵抗引起的细胞葡萄糖利用受损所必需的，而极低密度脂蛋白的代谢被增强以促进甘油三酯的运输。较少

The transport and-metabolic pathway of triglycerides (TG) in the placenta have not been studied in detail. The present study examined the characteristics of blood lipids in patients with Preeclampsia and gestational diabetes mellitus (GDM) and lipid metabolism in the fetoplacental system in these patients. Especially, this study measured the expressions of very low-density lipoprotein (VLDL) receptor mRNA and low-density lipoprotein (LDL) receptor mRNA in the placenta, aiming to elucidate the relationship between these mRNA expressions and the pathology. Informed consent was obtained from women (normal pregnant women and those complication) who delivered at our department. Serum levels of lipids and lipoproteins were measured. In addition, villous tissue was obtained from human placenta, and used as materials in the following experiments. RNA was extracted by the AGPC method, and Northern blot was performed. To compare the relative quantities of mRNA expression, the bands of mRNA expre … More ssion were scanned and quantitated. At delivery in the Preeclampsia and GDM groups, TG, VLDL levels were significantly higher than the levels in the normal pregnancy group. The VLDL receptor mRNA was significantly higher in the GDM group, lower in the Preeclampsia group. No significance difference in the LDL receptor mRNA was observed between the normal control, GDM and Preeclampsia. In all pregnancy groups, a positive correlation was Observed between the VLDL receptor mRNA expression and the TG or VLDL levels in umbilical blood. In the GDM group, three neonates with birth weights over 3500 g had high concentrations of TG and VLDL in the umbilical blood. At 1 month postpartum, although the blood glucose had normalized in a kind of Preeclampsia and GDM groups, serum TG and VLDL levels remained elevated, and high-density lipoprotein-cholesterol level was significantly lowered. The present study demonstrated for the first time that compared to the normal pregnant women, patients with Preeclampsia and GDM had (1)excessive lipids, especially TG, in the blood, which are the energy source in the placenta. (2) showed up-regulation of the expression of VLDL receptor mRNA in the placenta, (3) had elevated TG and VLDL levels in the umbilical blood, and (4) continued to have hyperlipemia even one month after parturition. The reason is speculated as follows. TG is necessary to compensate for impaired glucose utilization in cells because of insulin resistance, and VLDL metabolism is augmented for the transport of TG. Less