Patterning the renal vascular bed.

The renal vascular bed has a stereotypic architecture that is essential for the kidney's role in excreting metabolic waste and regulating the volume and composition of body fluids. The kidney's excretory functions are dependent on the delivery of the majority of renal blood flow to the glomerular capillaries, which filter plasma removing from it metabolic waste, as well as vast quantities of solutes and fluids. The renal tubules reabsorb from the glomerular filtrate solutes and fluids required for homeostasis, while the post-glomerular capillary beds return these essential substances back into the systemic circulation. Thus, the kidney's regulatory functions are dependent on the close proximity or alignment of the post-glomerular capillary beds with the renal tubules. This review will focus on our current knowledge of the mechanisms controlling the embryonic development of the renal vasculature. An understanding of this process is critical for developing novel therapies to prevent vessel rarefaction and will be essential for engineering renal tissues suitable for restoring kidney function to the ever-increasing population of patients with end stage renal disease.