The bladder is a hollow ball, with the wall of the bladder composed of several components; such as serosa, muscularis, submucosa, musculris mucosa, and lamina propria. The endothelial cells lining the microvasculature of the circulatory system in the bladder play a critical “gatekeeper” role in the inflammatory process through their ability to recruit circulating immune cells into tissues. Endothelial cells in the bladder wall stimulated with thrombin or tryptase causes phospholipid metabolite production. They may also contribute to the inflammatory process in interstitial cystitis. HBdMEC provide a useful in vitro model to study the role of endothelial cells in physiological and inflammatory conditions. Human Bladder Microvascular Endothelial Cells are also useful tools to develop disease models for High Throughput and High Content Screening.