Dynamic aspects of thrombus formation in mutant analbuminemic rats

To elucidate the mechanism for thrombus formation in hypoalbuminemic and hyperlipidemic subjects, the experimental thrombus formation was analyzed in Nagase analbuminemic rats (NAR). The mutant rat reveals similar biochemical findings to those of NS, such as hyperlipidemia. When thrombus was induced in a small branch of the mesenteric artery by inserting a glass micropipette, thrombus formation was observed within 4 min in NAR and Sprague-Dawley rat (SDR). In SDR, the thrombus gradually grew up in size and detached from the inserted glass micropipette within 4 min after its formation. In contrast, the thrombus formed in NAR did not dissociate from the micropipette until 10-13 min after its formation. The maximum size of the thrombus formed in NAR was about 4 times larger than that in SDR. In the presence of fibrin, the plasma samples from NAR inhibited the activity of tissue-plasminogen activator (t-PA) 1.7 times more potently than did SDR plasma. Plasma gamma 2-plasmin inhibitor activity was significantly higher than that in SDR. Albumin significantly enhanced the t-PA-catalyzed activation of plasminogen, suggesting that the serum albumin might contribute, at least in part, to the plasma fibrinolytic activity. Thus, the higher thrombogenic potential in NAR than in SDR might be due to the reduced thrombolytic activity in NAR.