Extracellular matrix (extracellular components)

Abstract

This chapter discusses the extracellular matrix and its components. Amianthoid (asbestoid) change is one of several age-associated regressive changes seen in hyaline cartilage. It is characterized by the development of quite coarse fibers called amianthoid fibers, which in gross wet specimens of human costal cartilage present as silvery threads and plaques in the central regions. Light microscopic studies show that amianthoid areas have less glycosaminoglycans in them than the surrounding cartilage and the lacunae in the vicinity of such areas are devoid of chondrocytes. Such findings are in keeping with the idea that amianthoid change is a part of a regressive or degenerative change in cartilage. Electron microscopic studies show that the filaments comprising oxytalan fibers have about the same width as the filaments in elastic fiber fibrils. Tetraphenylporphine sulfonate has a specific affinity for elastic fibers. It gives a bright red fluorescence to elastic fibers when injected into animals.