Renal microvascular assembly and repair: Power and promise of molecular definition  Takamune Takahashi, Uyen Huynh-Do, Thomas O. Daniel  Kidney International  Volume 53, Issue 4, Pages 826-835 (April 1998) DOI: 10.1111/j.1523-1755.1998.00822.x Copyright © 1998 International Society of Nephrology Terms and Conditions

Figure 1 Glomerular microvascular development.(A) Proliferative expansion of this epithelial mass of cells induces vascular endothelial growth factor (VEGF) expression and increases the population of flk-1 expressing “angioblasts” dispersed in adjacent sites. (B) VEGF, basic FGF and possibly ephrinB1 direct migration of angioblasts to the developing glomerular vascular cleft. (C) Coordinated recruitment and differentiation of mesangial and endothelial cells involves paracrine signaling through receptors for platelet-derived growth factor B (PDGF B) and possibly for angiopoietin-1. EphB1 receptors may direct homologous cell-cell recognition required for coordinated endothelial assembly and capillary network formation. VEGF likely provides ongoing proliferative signals, at least at early steps in the process. (D) Late steps in microvascular maturation involve formation of endothelial cell-cell junctions, growth arrest, and remodeling of matrix, where a number of cell to cell signaling systems may be invoked, including receptor protein tyrosine phosphatases (RPTPs) and cadherins. Kidney International 1998 53, 826-835DOI: (10.1111/j.1523-1755.1998.00822.x) Copyright © 1998 International Society of Nephrology Terms and Conditions

Figure 2 Alternative post-injury responses.Capillary reassembly into new microvascular networks leads, under optimal circumstances, to remodeling and repair of the glomerulus through processes shown on the left. Alternatively, disordered repair or remodeling may contribute to the destructive processes depicted on the right, ultimately resulting in glomerulosclerosis. Kidney International 1998 53, 826-835DOI: (10.1111/j.1523-1755.1998.00822.x) Copyright © 1998 International Society of Nephrology Terms and Conditions