The potent platelet inhibitory effects of S-nitrosated albumin coating of artificial surfaces

OBJECTIVES We studied the ant;thrombotic effect of coating glass, collagen and metal stent surfaces with bovine serum albumin (BSA) covalently modified to carry S-NO functional groups denoted (pS-NO-BSA). METHODS Video-enhanced light microscopy was used to visualize canine blood platelet adhesion and aggregation in a parallel plate glass chamber. Platelet adhesion was observed for 60 min on glass, glass coated with BSA, glass coated with pS-NO-BSA, collagen I (CO) surface, CO coated with BSA and CO coated with pS-NO-BSA. We also coated Palmaz-Shatz (P-S) stents with pS-NO-BSA. Coated and uncoated stents were then immersed in porcine platelet-rich plasma for two min and the platelet cyclic GMP level was measured. In six anesthetized pigs, coated and uncoated stents were placed in the carotid arteries and [In-111]-labeled platelets were circulated for 2 h, The stented arteries were then removed and placed in a gamma well counter. RESULTS There was significantly less platelet attachment, adhesion and aggregation on the pS-NO-BSA. coated surfaces compared with the BSA coated and uncoated surfaces. The pS-NO-BSA coating increased the platelet cGMP levels to 5.9 +/- 0.7 pmoles/10(8) platelets compared with 2.7 +/- 0.9 pmoles/10(8) platelets for control (p < 0.01). The average gamma ray count from [In-111]-labeled platelets that attached to the coated stents was 90,000 +/- 42,000/min and 435,000 +/- 290,000/min for the uncoated stents (p < 0.01). CONCLUSIONS The pS-NO-BSA coating of thrombogenic surfaces reduces platelet adhesion and aggregation, possibly by increasing the platelet cGMP. This inhibitory effect appears to be a consequence of the direct antiplatelet actions of NO combined with the antiadhesive properties (C) 1999 by the American College of Cardiology.