Plasma fibronectin levels in sepsis: influencing factors.

Low plasma levels of the opsonic glycoprotein fibronectin (Fn) have been suggested to imply an impaired host defense against sepsis. However, the mechanism(s) behind Fn depletion in sepsis are obscure. We measured the Fn plasma concentration in 32 patients 12 to 24 h after the diagnosis of septic shock. Although the average plasma level was low (214 +/- 80 [SD] mg/L) compared to that of a reference material (p less than .001), the range was great (60 to 403 mg/L). A multivariate analysis of some possible influencing factors showed significant (p less than .01) positive correlations to the prothrombin level (r = .62) and the amount of insulin infused per 24 h (r = .63). The relationships to disseminated intravascular coagulation-related variables, hemodilution, and outcome were weak. Cryoprecipitate was infused into 16 patients; Fn levels increased by 52 +/- 18% of the expected increase. The most severely ill patients displayed the lowest rates of increase. The postinfusion decrease in Fn plasma concentration indicated that the plasma half-life of cryoprecipitate Fn was about 25 h. The results support the concept that decreased Fn synthesis, probably in the liver, is the major reason for Fn depletion in sepsis, rather than an increased rate of consumption.