Regulation of kidney development by Shp2: an unbiased stereological analysis

Characterization of growth, glomerular number, and tubular proteins in the developing rhesus monkey kidney

An essential step in the translation of cell-based therapies for kidney repair involves preclinical studies in relevant animal models. Regenerative therapies in children with congenital kidney disease may provide benefit, but limited quantitative data on normal development is available to aid in identifying efficient protocols for repair. Nonhuman primates share many developmental similarities with humans and provide an important translational model for understanding nephrogenesis and morphological changes across gestation. These studies assessed monkey kidney size and weight during development and utilized stereological methods to quantitate total number of glomeruli. Immunohistochemical methods were included to identify patterns of expression of tubular proteins including Aquaporin-1 (AQP1), AQP2, Calbindin, E-Cadherin, and Uromodulin. Results have shown that glomerular number increased linearly with kidney weight, from 1.1 × 10(3) in the late first trimester to 3.5 × 10(5) near term (P < 0.001). The ratio of glomeruli to body weight tripled from the late first to early second trimester then remained relatively unchanged. Only AQP1 was expressed in the proximal tubule and descending Loop of Henle. The ascending Loop of Henle was positive for AQP2, Calbindin, and Uromodulin; distal convoluted tubules stained for Calbindin only; and collecting tubules expressed AQP2 and E-Cadherin with occasional Calbindin-positive cells. These findings provide quantitative information on normal kidney ontogeny in rhesus monkeys and further support the importance of this model for human kidney development.

Estimating total nephron number in the adult kidney using the physical disector/fractionator combination

Nephron number has emerged as a useful parameter for assessing the roles of specific genes and feto-maternal environmental factors in kidney development. Nephron number is also of clinical interest due to increasing evidence suggesting that low nephron number is associated with increased risk for developing chronic adult disease, including cardiovascular and renal disease. The physical disector/fractionator combination is considered the gold standard method for estimating total nephron number in kidneys. Here we describe the use of this method to estimate total nephron number in mouse and rat kidneys, and variations to the method required to estimate nephron number in larger species, including human.