To clarify whether glycation of fibrinogen (Fbg) and fibronectin (Fn) affects the formation of soluble fibrin monomer complexes (SFMC), a study was carried out in vitro. Fbg and Fn purified from human plasma were incubated for 4 days at 37°C in phosphate buffered saline, pH 7.4, containing 500 mM glucose. Four different samples were tested. Sample A was composed of glycated Fbg and Fn B, of non-glycated Fbg and glycated Fn C, of glycated Fbg and non-glycated Fn D, of non-glycated Fbg and Fn. Equal amounts of thrombin were added to each sample. The concentrations of SFMC produced by thrombin were measured and the ratios of Fn to fibrin (ogen) in the complex were estimated by SDS-PAGE. The highest level of SFMC was found in A, and the lowest concentration in D. In contrast, D showed the highest ratio of Fn to fibrin (ogen) and A showed the lowest ratio. From these results, SFMC generated in A seemed to have more fibrin and less Fn than the other three samples. The high SFMC level in A may be caused by the increase in it's fibrin content. Therefore, fibrin-rich and Fn-poor SFMC such as A was thought to have a decreased solubility of fibrin.
It is concluded that glycation of Fbg and Fn resulted in elevation of the SFMC level by formation of fibrin-rich and Fn-poor SFMC. This SFMC may precipitate fibrin on the vessel wall in vivo more easily.