Comparative Biology of the Normal Lung Extracellular Matrix

The extracellular matrix (ECM) of the lung provides tensile strength, intrinsic elasticity, and a substrate upon which cells reside and function. The ECM is comprised of a multitude of glycoproteins, proteoglycans, and other molecules whose ultimate composition and arrangements allow for the normal functioning of the various lung compartments. Despite decades of investigation, we are only now beginning to better understand the composition of the human lung ECM. Recent technological advances now allow a direct comparison of human lung ECM with that of experimental animal models, confirming or refuting previous observations. This chapter outlines the known components of the ECM, explores our current knowledge of lung ECM from embryonic development through postnatal life, and discusses newer techniques available to isolate and better study lung ECM.