ASSESSMENT OF CLOT LYSIS TIME TISSUE FACTOR-INDUCED BY EXOGENOUS T-PA IN HEALTHY SUBJECTS BY USING A MICROPLATE READER
Abstract number: P-S-389
Cellai1 A., Lami1 D., Paniccia1 R., Bandinelli1 B., Alessandrello Liotta1 A., Fedi1 S., Abbate1 R., Gensini2 G., Prisco1 D.
11Department of Medical and Surgical Critical Care, Thrombosis Centre, Azienda Ospedaliero-Universitaria Careggi, Florence 22Department of Medical and Surgical Critical Care, Thrombosis Centre, Don Carlo Gnocchi Foundation, ONLUS IRCCS Florence, Florence, Italy
How-to-cite Cellai A, Lami D, Paniccia R, Bandinelli B, Alessandrello Liotta A, Fedi S, Abbate R, Gensini G, Prisco D. ASSESSMENT OF CLOT LYSIS TIME TISSUE FACTOR-INDUCED BY EXOGENOUS T-PA IN HEALTHY SUBJECTS BY USING A MICROPLATE READER. J Thromb Haemost 2007; 5 Supplement 2: P-S-389
Abstract
Introduction: Recently, in Leiden Thrombophilia Study (LETS) low plasma fibrinolytic potential has been demonstrated to be a risk factor for venous thrombosis, and TAFI plays a role as regulator between the coagulation and the fibrinolytic system. As the study of fibrinolysis has relevant problems of standardization, the aim of this study was to detect the feasibility of clot lysis time tissue factor-induced by exogenous t-PA (CLT) in a routine clinical setting and its correlation with TAFI antigen and activity.
Methods: We studied 170 (Male/Female, 91/79; mean age 43.914.2 yrs) clinically healthy subjects- volunteers from our hospital. Plasma was prepared shortly after citrated blood collection by centrifuging at 2000g for 10 minutes at 4°C and kept at -70°C until the investigation. Clots were formed in the presence of tissue factor (Innovin; Dade Behring, 1/1000 final dilution), tissue plasminogen activator (Actilyse; Boehering Ingelheim, 160 ng/ml, final concentration), platelet phospholipids (final concentration 10mM), and CaCl2 (final concentration 17mM). Lysis was monitored over time at 37°C with microplate reader by the reduction in turbidity.
Results: The mean of CLTs was 44.29.7 min, median 43(19-72) min. Intra- and inter-assay coefficient of variations were found to be 2.8% (44.31.2 n=8) and 3.9%(42.11.6 n=5) respectively. CLTs progressively increased with age (p=0.01 <50 yrs vs >50 yrs). No difference was observed between males and females (45.110.3 min and 43.38.9 min,respectively). Significant correlations were observed between CLT and plasma TAFI antigen and activity (rho 0.36 and 0.23 respectively; p<0.001 for both).
Conclusions: We found a weakly association between TAFI levels and CLTs, probably because CLT is determined by the balance of the levels of all fibrinolytic proteins. In addition, these results indicate that lysis time determination,as described, has an acceptable performance which suggests the feasibility of its use for clinical research.
