Therapeutic administration of fibronectin: current uses and potential applications.

Fibronectins are a class of multifunctional glycoproteins that exist in soluble and insoluble forms. These glycoproteins are found in nearly all body fluids and in tissue extracellular matrices. Alterations in the normal synthesis, release, and distribution of fibronectins are characteristic features of certain human pathophysiologic conditions. The therapeutic administration of plasma fibronectin to human patients with defects in corneal wound healing and critically ill adult patients with multisystem organ failure appears clinically beneficial, although confirmation is needed from additional trials in progress. In vitro data suggest a role for fibronectin in enhancing (directly and indirectly) the function of phagocytes isolated from the blood of newborn infants. Although as yet untested, it is possible that fibronectin administration to the immunologically immature human neonate may improve host defenses and reduce the risk of nosocomial infection. Additional research is needed to define the factors that regulate the synthesis, isoform expression, and clearance of endogenous fibronectins during normal fetal and neonatal development. Continued research to define the role of endogenous fibronectins in augmenting the inflammatory response of the neonatal host is also required before rational immunotherapeutic interventions can be initiated.