Plasma fibronectin concentrations in breast fed and formula fed neonates.

Plasma fibronectin concentration was measured in neonates of 2 to 5 days of age. Although breast fed and formula fed infants were similar in demographic characteristics, the mean (SD) plasma concentration of fibronectin in 26 breast fed infants, 237 (117) mg/l, was significantly higher than in 27 formula fed infants (171 (91) mg/l). Fibronectin was detected in five colostrum specimens (mean concentration 13.4 mg/l). Similar bands were detected after gel electrophoresis of purified adult plasma fibronectin and whole plasma from breast fed and formula fed neonates after staining or immunoblotting. Fibronectin isolated from breast milk also appeared similar to purified plasma fibronectin. It is possible, although unlikely, that fibronectin is absorbed intact from ingested colostrum. Alternatively, a factor(s) might be present in colostrum that contributes to the regulation of plasma fibronectin concentration.