Plasma fibronectin: relevance for anesthesiology and intensive care

Plasma fibronectin has been postulated to be an essential mediator of normal reticuloendothelial system (RES) function. The acute depletion of fibronectin is thought to impair RES function, whereas its repletion in states of deficiency has been reported to improve RES function. In vitro studies have documented fibronectin's ability to bind to some nonbacterial microaggregates and to promote the phagocytosis of bound targets by the RES. These properties may, however, be influenced by the in vivo milieu. There is substantial evidence for a parallelism between RES function and plasma fibronectin levels following blunt trauma in animal models; however, this association is not seen in experimentally induced intravascular coagulation, acute inflammation, and sepsis. Clinically, subnormal fibronectin levels are clearly associated with the triad of intravascular coagulation, organ failure and sepsis. Fibronectin is, however, not the only plasma protein reduced in these patients, nor is it an outstanding predictor of such complications. The therapeutic efficacy of fibronectin administration remains controversial. Whereas initial reports suggested therapeutic benefits of fibronectin-enriched cryoprecipitates, subsequent studies have produced negative results. Prospective, randomized, controlled clinical trials with purified fibronectin are needed before fibronectin should be recommended as an adjunct to the established principles of intensive care.