A morphological investigation of sexual and lateral dimorphism in the developing metanephric kidney.

Sexual dimorphism is a prominent feature of renal physiology and as a consequence, it differentially affects predisposition to many adult kidney diseases. Furthermore the left and right kidneys differ in terms of their position, size and involvement in congenital malformations of the urogenital tract. We set out to determine whether differences in the program of branching morphogenesis that establishes the basic architecture of the kidney were apparent with respect to either sex or laterality in mouse embryonic kidneys. This was achieved using a combination of optical projection tomography imaging and computational analysis of many spatial metrics describing the branched ureteric tree. We undertook a comprehensive assessment of twelve aspects of ureteric morphology across developmental time and we found no consistent differences between kidneys of different sexes or laterality. These results suggest that dimorphism is established after birth or at a physiological or cellular level that is not reflected in the morphology of the ureteric tree.