The functional role of ECM

Physical, chemical, and mechanical properties of all body tissues depend on the composition and architecture of the extracellular matrix (ECM). Besides providing support and mechanical properties and being the reservoir of substances participating to the body metabolism, ECM is the microenvironment of cells, communicates with them with specific signaling molecules, and regulates their behavior and intercellular communications. ECM participates in cell activities, such as cell proliferation, adhesion, migration, differentiation showing a structure extremely dynamic. Its components continuously undergo a remodeling process comprising deposition, degradation, and modifications, which are fundamental for the formation of the tissue architecture. The principal components of ECM comprehend a complex mixture of structural proteins, proteoglycans, and multi-adhesive matrix proteins that are produced intracellularly by resident cells, secreted into the ECM via exocytosis and finally assembled. The chapter reviews ECM composition and main functions, focusing in particular on ECM biochemical and physical properties and on the cell–ECM interactions. The role of ECM on the properties of some body tissues is described, and the mechanisms of ECM scarless healing in fetuses are compared with those occurring in adults