Human Renal Medullary Epithelial Cells play a crucial role in renal function. The renal medulla is the inner most part of the kidney. The main structures inside the medulla are pyramid-shaped; known as renal pyramids. It consists of the medullary collecting ducts, loops of Henle, vasa recta and also the interstitium. The unique spatial arrangement of these components is essential for the regulation of urine concentration and other specialized kidney functions. It functions in renal water reabsorption by building up a high hypertonicity, which draws water out of the thin descending limb of the loop of Henle and the collecting duct system. Furthermore, urea efflux from the internal medullary collecting duct causes hypertonicity.

Human Renal Medullary Epithelial Cells in culture provide a useful in vitro model for studying the relationship between epithelial cells and renal disease. They are also useful tools to stablish in vitro disease models for High Throughput and High Content Screening.