Pulmonary endothelium forms the inner lining of blood vessels, where it interprets the complex mechanical and chemical environment within the circulation and adjusts its behavior to facilitate vascular homeostasis. Although endothelium fulfills many essential functions, including regulation of vascular pressure, circulating cell transmigration, coagulation, and hormone metabolism and/or delivery, a principal role is to form a semi-permeable barrier that limits fluid, solute and macromolecular access to the interstitial space. Physiological properties that govern such permeability...