Overview: Nonmammalian Organisms for Studies of Kidney Development and Disease

[摘要] All animals must excrete the waste products of metabolism and maintain a constant body composition despite changes in the external environment. In higher animals, these functions are performed by specialized excretory organs. The excretory organs range from a single excretory cell in the nematode Caenorhabditis elegans to Malpighian tubules in insects; nephridia in annelids; rectal glands in sharks; and kidneys in amphibians, birds, and mammals. Although many of these organisms are separated by hundreds of millions of years of evolution, their excretory organs often show a striking degree of conservation of form and function. For example, the Malpighian tubules of fruit flies (Drosophila) consist of blind-ended epithelial tubes that emerge from the hindgut and project into the coelomic cavity. Fruit flies consume a diet that is rich in potassium (not unlike some dialysis patients!), so a major function of Malpighian tubules is elimination of excess potassium. This process is accomplished by ion transporters, such as bumetanide-sensitive Na+-K+-2Cl− co-transporters, which are not unlike those found in mammalian secretory epithelia (1). Fluid is secreted into the early Malpighian tubule and selectively reabsorbed in the late tubule, analogous to filtration-reabsorption in the mammalian nephron. Even the genes that are required for the embryonic development of excretory organs are conserved between highly disparate species. Such similarities raise the possibility that experimentally tractable organisms, such as Drosophila, might serve as useful models for understanding kidney biology in higher organisms.

[学科分类] 泌尿医学

[关键词] Bone marrow necrosis;Sickle cell disease;Hyperhemolysis syndrome