ACTA FAC. MED. NAISS. 2004; 21 (3):163-170

     Review article

Marija Daković-Bjelaković¹, Natalija Stefanović¹, Slobodan Vlajković¹, Rade Čukuranović¹, Svetlana Antić¹, Goran Bjelaković², Dejan Mitić³

¹Institute of Anatomy, Medical Faculty, University of Niš;
²Department of Internal Medicine, Medical Faculty, University of Niš;
³Clinic of gynecology and obstetrics, Clinical Center Niš

    The kidney is one of the main excre tory and homeostatic organs of the body. It excretes most of the final products of metabolism, and controls the concentration of certain constituents of the body fluids. Organogenesis of the kidney is complex and stepwise process with the successive appearance of pronephros, mesonephros, and metanephros. Pronephros and mesonephros are the transient structures with littleex cretory capacity, which precede the formation of the adult (metanephric) kidney. Metanephros grow as the result of the reciprocal inductive interactions between the two primordial mesodermal deri vates: ureteric bud, an epithelial out growth of the Wolffian duct, and metanephric blastema, a group of mesenchymal cells. The ureteric bud causes the metanephric mesenchyme to differentiate and form nephrons, whilst the metanephric mesenchyme causes the ureteric bud to grow and bifurcate to form collecting ducts. The nephron pro gresses through four developmental stages, which are described as 1) vesicle, 2) comma-shaped and S-shaped stages, 3) developing capillary loop, and finally 4) maturing glomerulus stage.
    Despite its importance, the origin of the kidney vasculature is not completely elucidated. As the renal vesicle invaginates, signals, presumably elaborated by the cells of the vascular cleft, recruit angioblasts or endothelial cells into the forming glomerulus. Once within the vascular cleft, the endothelial cells undergo mitosis and assemble into a capillary as the glomerulus expands. The glomerular basement membrane is assembled from extracellular matrix components produced by both the endothelium and podocytes. Finally, mesangial cells or “glomerular pericytes” are also recruited into the glomerulus and they contribute to the stabilization of the glomerular capillary tuft.
    The fetal kidney produces dilute urine which is a major input into the amniotic fluid. Any factor preventing urine production by the kidneys could thus induce fetal abnormalities. Recently, several studies emphasized the relation of kidney development and adult renal diseases.

    Key words: kidney, development, nephron