Cloning of the gene which regulates glomerular development

体液的平衡是由肾脏维持的，肾脏含有200万个用于血液过滤的肾小球。肾小球是在肾脏发育过程中由鲍曼氏囊与毛细血管协调生长而形成的。血管内皮生长因子（VEGF）是一种重要的血管生成细胞因子，已知VEGF缺乏对早期胚胎阶段的小鼠是致命的。由于培养肾脏的VEGF分泌量根据发育阶段而有所不同，因此通过用抗体阻断新生小鼠的内源性VEGF活性，在体内研究了VEGF在肾脏发育中的作用，其中大多数器官已经发育，但肾脏仍在发育中。抗体治疗的动物表现出正常生长，但全身水肿。肾皮质浅部血管形成受到干扰，生肾区缩小，发育中的肾单位数量明显减少。在抗体处理的小鼠中观察到许多异常肾小球，缺乏毛细血管丛，并且在其Bowman囊中的VEGF表达显示出代偿性增加。这些结果表明，VEGF介导鲍曼氏囊和毛细血管内皮细胞之间的通信，用于发展肾小球以及促进肾发生。总之，VEGF可能是肾脏发育，特别是肾小球形成的重要分子。

Homeostasis of body fluid is maintained by the kidneys, which contain two million glomeruli for blood filtration. A glomerulus is formed by growth of Bowman's capsule harmonized with a capillary during kidney development. The vascular endothelial growth factor (VEGF) is an essential angiogenic cytokine, and VEGF-deficiency is known to be fatal to mice in early embryonic stages. As secretions of VEGF from cultured kidneys vary according to developmental stages, the role of VEGF in kidney development was studied in vivo by blocking the endogenous VEGF activity with antibody in newborn mice, in which most organs are already developed but kidneys are still developing. The antibody-treated animals showed normal growth but systemic edema. Vessel formation in the superficial renal cortex was disturbed, nephrogenic areas were diminished and the number of developing nephrons decreased signigicantly. Many abnormal glomeruli, lacking capillary tufts, were observed in the antibody-treated mice, and VEGF expression in their Bowman's capsule showed compensatory increase. These results suggest that VEGF mediates communication between the Bowman's capsule and capillary endothelial cells for developing a glomerulus as well as promoting nephrogenesis. In conclusion, VEGF is likely to be an essential molecule for kidney development, and especially for glomerulogenesis.