| The extracellular matrix (ECM) is a complex network of secreted macromolecules located in the extracellular space. The ECM of skin and bone provides the structural framework of the body; however, in all tissues it has a central role in regulating basic cellular processes, including proliferation, differentiation, migration and cell-cell interactions. The macromolecular network of the ECM is made up of collagens, elastin, glycoproteins, and proteoglycans, secreted by connective tissue cells such as fibroblasts, chondrocytes, and epithelial cells. The components of the ECM are in intimate contact with their cells of origin and form a three-dimensional gelatinous bed in which the cells thrive. Proteins in the ECM are also bound to the cell surface, so that they transmit signals resulting from stretching and compression of tissues. The relative abundance, distribution of proteins, and molecular organization of ECM components vary enormously among tissues, depending on their structure and function. Changes in the composition and turnover of the ECM are associated with chronic diseases, such as arthritis, atherosclerosis, cancer, and fibrosis.
|
