Interstitial Stroma

The interstitial stroma is the medium bathing the nephrons, ureteric epithelia (ureteric tips, trunk and collecting duct system) and renal vasculature, and is composed of renal support cells, including fibroblasts and macrophages, and mesenchymal stroma or interstitial cells. The medullary interstitium of the adult kidney consists of lipid-laden interstitial cells, lymphocyte-like cells, pericytes and extracellular matrix (ECM), and provides a structural supportive framework around collecting ducts, loops of Henle and vasa recta. Additional functions of mature medullary interstitial cells may include production of ECM and prostaglandins.