Adsorption of proteins from infant and adult plasma to biomaterial surfaces

The hemostatic mechanism of the newborn is immature. In general, the clotting times in screening tests are prolonged, the coagulation factors are low, and the coagulation inhibitors (with the exception of alpha-2-macroglobulin) are low. Recognizing that many of the proteins present in infant plasma are at low levels, it is of interest to determine if, following exposure to artificial surfaces, the profile of adsorbed proteins is different for infant versus adult plasma. The question of whether differences in protein profiles could lead to differences in thromboembolic episodes associated with the use of central venous catheters (or other blood-contacting devices) in infant versus adult subjects also is relevant. To address these issues, the adsorption of proteins from pooled infant plasma and pooled normal adult plasma to three different polymer surfaces (polyvinyl chloride, PVC; polymethyl methacrylate, PMMA; and polyethylene oxide-modified polyurethane, PEO-PU) was studied using SDS-PAGE and immunoblotting techniques. The total amount of protein adsorbed to each surface also was determined. It was found that the PMMA and PVC surfaces adsorbed considerably more protein than the PEO-PU surface. Furthermore, the amount of protein adsorbed to the PMMA and PVC surfaces from infant plasma was significantly less than that adsorbed from adult plasma. No such difference was seen for the protein-repellent PEO-PU surface. The immunoblot responses of proteins bound to the PMMA and PVC surfaces from infant plasma were, in general, weaker than those bound from adult plasma. It is likely that these differences were due to decreased protein levels in infant plasma.