Establishment of a mouse model for the induction of preeclampsia by soluble VEGFR-1/flt-1 and its modulation by exogenous treatment with antibodies and receptor ligands

在过去的24个月中，我们的工作假设是，VEGF-A和PIGF必须被很好地调节，sFlt-1和VEGF/PIGF水平之间的平衡似乎在维持血管内平衡方面起着关键作用，这种平衡的失调参与了几种血管疾病。这种从胎盘分泌到母体血液的sFlt-1水平的增加与循环中游离VEGF-A和PIGF水平的下降有关，并导致体内内皮功能障碍。在过去的一段时间里，我们成功地利用腺病毒在Balb/c小鼠体内过表达sFlt-1建立了子痫前期小鼠模型。这是通过向8-11周龄动物的尾静脉注射2.5-5x108病毒颗粒来实现的。8~10天后处死动物，取肾组织行肾小球组织化学分析。可溶性Flt-1过表达导致肾小球微血管和微管的崩溃，表现为肾小球微血管管腔的强烈减少。注入腺病毒后，经病毒处理的动物肝脏体积也显著增加，表明注射的病毒颗粒大多定位于肝脏。到目前为止，还没有对血压和蛋白尿等参数进行详细调查。为了调节肾脏的病理效应，我们已经开始利用噬菌体展示技术开发阻断抗体。由于这是该项目的高风险部分，我们能够从一个合作小组招募Flt-1的阻断抗体。现在将在最后一个阶段详细分析sflt-1对肾功能障碍的影响。为此，我们还将开始一项合作，通过遥测测量高血压的诱导，并想调查我们的问题，即Flt-1的阻断抗体是否可以调节实验中在小鼠中诱导的先兆子痫的影响。

Our work hypothesis during the last 24 months was that VEGF-A together with PIGF must be very well regulated and that intratissual balance between sFlt-1 and VEGF/PIGF levels seems to play a crucial role for maintaining vascular homeostasis and that dysregulation of this balance is involved in several vascular diseases. This increasing levels of sFlt-1 secreted from placenta into the maternal blood are associated with decreasing circulating levels of free VEGF-A and PIGF and results in endothelial dysfunction in vivo. In the last period we have sucessfully established a mouse model for preeclampsia using adenoviral overexpression for sFlt-1 in Balb/c mice. This was achieved by intravenous injection of 2.5-5 x108 virus particles into the tail vein of 8-11 week old animals. After 8-10 days animals were sacrified and the glomeruli of the kidney were analyzed by histochemical analysis. Soluble flt-1 overexpression leads to a collapse of microvessels and tubes indicated by a strong reduction of microvessel lumen in a glomerulus. Injection of adenovirus also lead to a massive increase in liver volumen of virus treated animals, indicating that most of the injected virus particles were localized in the liver. So far parameter like blood pressure and proteinuria were not investigated in detail. In order to modulate the pathological effect in the kidney we have started to develop blocking antibodies by phage-display. Because this is a high risk part of the project, we were able to recrute blocking antibodies for flt-1 from a collaborating group. The sflt-1 effect induced for kidney dysfunction will now be analyzed in the last period in great detail. For this purpose we will also start a collaboration to measure induction of high blood pressure by telemetry and want to investigate our question, if blocking antibody to flt-1 can modulate the effect of preeclampsia experimentally induced in mice.