ABSTRACT

The biological phenomenon of organismal aging involves a complex series of progressive and irreversible changes. Fibronectins are high molecular weight glycoproteins present on cell surfaces, in connective tissue matrices, in basement membranes, and in extracellular fluids including plasma. Different forms of fibronectin comprise a group of structurally related, large glycoproteins with similar biological activities. The ability of soluble cellular fibronectins to interact with collagens, heparin, and the cell surface was also evaluated. An immunoassay was used to quantitate the levels of fibronectin retained in the cell layers of confluent cultures at equivalent cell densities of early and late passage cells. Other glycosylation differences between amnionic fluid fibronectin and adult plasma fibronectin and between fetal placental fibronectin and plasma fibronectin were also reported. Fibronectin distribution was analyzed in tissues obtained from donors afflicted with disease conditions associated with advancing age. Age-related changes in the localization, structure, and function of fibronectins have been reported.