Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan 14000, México, D.F., Mexico.
Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan 14000, México, D.F., Mexico.
J Steroid Biochem Mol Biol. 2014 Oct;144 Pt A:44-9. doi: 10.1016/j.jsbmb.2013.12.014. Epub 2013 Dec 24.
Placenta is an extrarenal source of calcitriol and pregnancy is associated with increased maternal serum levels of this hormone. It has been reported that insulin-like growth factor I (IGF-I) stimulates placental calcitriol synthesis and that circulating levels of both hormones are low in preeclampsia. Since calcitriol production has not been determined in placental homogenates in preeclampsia, the aim of the present study was to establish if placental calcitriol synthesis and IGF-I concentration are altered in this tissue obtained from preeclamptic pregnancies. Placental samples were obtained from 8 preeclamptic (PE group) and 8 normotensive (NT group) pregnant women. Calcitriol synthesis was determined using [(3)H]-25(OH)D3 (2.94nM) as precursor and [(3)H]-1,25(OH)2D3 produced was calculated as the percentage of radioactivity co-eluting with unlabelled 1,25(OH)2D3 after two successive high pressure liquid chromatographies. Placental IGF-I levels were determined by RIA. In addition, maternal and umbilical calcitriol and IGF-I levels were also determined in these 2 groups using radioreceptor assay and RIA, respectively. The results of the present study showed that placentas from both groups were able to convert [(3)H]-25(OH)D3 into more polar metabolites. In the PE group, placental [(3)H]-1,25(OH)2D3 synthesis was significantly lower than in the NT group (19.6±6.2 vs 29.9±8.1fmoles/200mg wet weight, P=0.013). Regarding IGF-I, its levels were significantly lower in placentas of the PE group than in the NT group (15.2±3.9 vs 21.6±4.9ng/g wet weight, P=0.012). Maternal and umbilical calcitriol levels were significantly lower in the PE than in the NT group (P<0.001). In the PE group, serum IGF-I levels were significantly lower only in the maternal circulation (P<0.05). In conclusion, placental calcitriol synthesis and IGF-I levels are low in preeclampsia which may contribute to decreased local placental functions related to these two hormones and/or to decreased maternal and fetal pool of 1,25(OH)2D3 during preeclamptic pregnancies. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.
胎盘是钙三醇的肾外来源，妊娠会导致母体血清中这种激素水平升高。据报道，胰岛素样生长因子 I（IGF-I）刺激胎盘钙三醇的合成，而且在子痫前期中这两种激素的循环水平都较低。由于尚未在子痫前期的胎盘匀浆中确定钙三醇的产生，因此本研究的目的是确定从子痫前期孕妇中获得的胎盘组织中钙三醇的合成和 IGF-I 浓度是否发生改变。从 8 例子痫前期（PE 组）和 8 例正常血压（NT 组）孕妇中获得胎盘样本。使用 [(3)H]-25(OH)D3（2.94nM）作为前体，通过 [(3)H]-1,25(OH)2D3 的产生量来确定钙三醇的合成，其计算方法是将两次高效液相色谱后与未标记的 1,25(OH)2D3 共洗脱的放射性活性的百分比。通过 RIA 测定胎盘 IGF-I 水平。此外，还分别使用放射受体测定法和 RIA 测定了这两组产妇和脐带的钙三醇和 IGF-I 水平。本研究结果表明，两组胎盘均能将 [(3)H]-25(OH)D3 转化为更具极性的代谢物。在 PE 组中，胎盘 [(3)H]-1,25(OH)2D3 的合成明显低于 NT 组（19.6±6.2 对 29.9±8.1fmoles/200mg 湿重，P=0.013）。关于 IGF-I，PE 组胎盘中的水平明显低于 NT 组（15.2±3.9 对 21.6±4.9ng/g 湿重，P=0.012）。PE 组产妇和脐带的钙三醇水平明显低于 NT 组（P<0.001）。在 PE 组中，仅在母体循环中 IGF-I 水平显著降低（P<0.05）。总之，子痫前期胎盘钙三醇合成和 IGF-I 水平降低，这可能导致与这两种激素相关的局部胎盘功能下降，以及/或在子痫前期妊娠期间母体和胎儿 1,25(OH)2D3 池减少。本文是题为“第 16 届维生素 D 研讨会”的特刊的一部分。
