Fibrin surface coating

Figure 26. Reconstruction of the tunica intima on the inner surface of a clinically used polyethylene terephtalate vascular prosthesis. A non-modified inner surface of the prosthesis, B immobilization of defined assemblies of protein molecules (e.g., collagenfiarninin or collagen+fibrin) on the inner surface of the graft, C immunofluorescence of von Willebrand factor, a marker of the identity a differentiation of vascular endothelial cells, in human saphenous vein endothelial cells in cultures on the inner surface of a prosthesis coated with collagen and larninin, D detail of a layer of endothelial cells growing on a layer of collagen and fibrin. Note well developed talin-containing focal adhesion plaques. A, B conventional optical microscope, C, D confocal microscope Leica DM 2500 [30,31].

Jen CJ, Lin IS. Direct observation of platelet adhesion onto fibrinogen-coated and fibrin- coated surfaces. Am JPhysiol 1991 261 H1457-H1463. 

The thrombotic response (the time vs. platelet and fibrin deposition pattern) for uncoated PVC (shown in Figures 2 and 3) is a response to PVC that is coated with a complex mixture of proteins in the initial seconds of blood contact. Therefore, at least part of the thrombotic response on PVC is generated by a complex protein-coated surface composed of many proteins adsorbed in various conformations, including serum albumin, 7-globulin, fibrinogen, and fibronectin. However, these four proteins account for only 75% of the total protein in plasma and, therefore, significant amounts of other proteins not accounted for by our measurements may be adsorbed to the test surface. 

Thrombotic Response to Protein-Coated Surfaces. Overview. Although Figures 2, 3, 5, 6, and 8-11 show fibrin(ogen) and platelet responses to many different surfaces, all of the curves have a similar appearance. At the first datum of 2 min, an initial amount of deposition was gener-... 

Figures 12 and 13 are scanning electron micrographs showing the surface of y-globulin-coated PVC after 5 min of blood contact time. Platelets appear to cover the surface uniformly with little evidence of basal fibrin. The large spherical platelet thrombus in Figure 12 also contained no visible fibrin basal to the platelet thrombus.

The fibrin(ogen) and platelet response to y-globulin-coated Silastic was similar to that on y-globulin-coated PVC. On both surfaces the relative rate of deposition of fibrin(ogen) initially (Table I) was much less than that of the platelets. On Silastic, the preadsorbed y-globulin was 11 times more concentrated than the amount that would be adsorbed onto the uncoated surface. Not much embolization occurred during an experimental blood exposure time of 120 min. 

The thrombotic response at longer blood contact times on fibronectin-coated PVC followed the pattern of the response on y-globulin-coated PVC except that more fibrin(ogen) was found on the fibronectin-coated surface. 

Although affinity of preadsorbed fibronectin for platelets may be less than that of preadsorbed 7-globulin for platelets, the increased fibrin formation on the fibronectin-coated surface is sufficient to generate similarly sized thrombi. The interaction of fibronectin with PVC is probably similar in magnitude to that of 7-globulin with PVC because the time and magnitude of maximum deposition were similar. 

On Silastic, however, the thrombotic response to the fibronectin-coated surface was quite different than the response to the 7-globulin-coated surface. Initially, more fibrin(ogen) was deposited on the fibronectin-coated surface, whereas platelet adhesion was greatly diminished. At later times of blood contact, platelet adhesion to the fibronectin-coated surface increased... 

The embolization process on the fibronectin-coated PVC surface was quite different than the embolization process on fibronectin-coated Silastic. On fibronectin-coated PVC, 97% of the deposited thrombus [both platelets and fibrin(ogen)] were shed after 120 min of blood contact, while on fibronectin-coated Silastic only 75% of the deposited platelets and none of the fibrin(ogen) was released. This behavior is consistent with the observations shown in Figures 17 and 18 (fibronectin-coated PVC at 30 min and... 

Figure 18. Fibronectin-coated Silastic after 30 min of blood contact. Large adherent thrombus (center) is beginning to embolize. Surrounding surface coverage appears to be mostly fibrin with a few adherent platelets.

Figure 23. von Willebrand factor-coated PVC after 2 min of blood exposure. Platelets appear in groups and are attached to the surface, and the presence of fibrin is minimal. 

Skarja, G. A., Brash, J. L., Bishop, R, and Woodhouse, K. A. (1998). Protein and platelet interactions with thermally denatured fibrinogen and crosslinked fibrin coated surfaces, BigmgiSJTols, 19,2129-2138. 

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