Immunological Quantitation of Rabbit Plasminogen Activator Inhibitor-1 in Biological Samples

Thu-Hoa Ngo; Paul J. Declerck

doi:10.1055/s-0037-1614863

Thrombosis and Haemostasis, Table of Contents

Thromb Haemost 1999; 82(05): 1510-1515
DOI: 10.1055/s-0037-1614863

Rapid Communications

Schattauer GmbH

Immunological Quantitation of Rabbit Plasminogen Activator Inhibitor-1 in Biological Samples

Evidence that Rabbit Platelets Do not Contain PAI-1

Thu-Hoa Ngo

¹From the Laboratory for Pharmaceutical Biology and Phytopharmacology, Faculty of Pharmaceutical Sciences, Katholieke Universiteit Leuven, Belgium

,

Paul J. Declerck

¹From the Laboratory for Pharmaceutical Biology and Phytopharmacology, Faculty of Pharmaceutical Sciences, Katholieke Universiteit Leuven, Belgium

› Author Affiliations

Abstract

Summary

Two immunoassays for the specific quantitation of rabbit plasminogen activator inhibitor-1 (PAI-1) antigen and activity in biological samples were developed and applied for the evaluation of PAI-1 in rabbits. Levels of PAI-1 antigen in rabbit plasma were 9.8 ± 4.6 ng/ml (mean ± SD, n = 6), with a corresponding value of 20.5 ± 13.5 ng/ml for PAI-1 activity. In rabbit serum PAI-1 antigen was 11.8 ± 4.9 ng/ml (n = 6) and PAI-1 activity was 2.9 ± 2.0 ng/ml (n = 6). Endotoxin injection (20 μg/kg, iv) induced a time-dependent increase of both PAI-1 antigen and PAI-1 activity levels in rabbit plasma, eventually resulting in a 40- to 90-fold increase (p <0.0001 vs baseline). A linear correlation was found between PAI-1 antigen and activity levels in normal plasma (r = 0.90, n = 6, p <0.05) and in plasma from endotoxin-treated rabbits (r = 0.98, n = 20, p <0.001). Analysis of PAI-1 antigen and activity in lysates of washed rabbit platelets revealed the absence of PAI-1 (i.e. <0.03 ng/10⁸ platelets).

In conclusion, development of specific immunological assays allowed the quantitation of PAI-1 in rabbit samples. In striking contrast to other species (human, rat, mouse, pig) rabbit platelets lack detectable amounts of PAI-1 (i.e. >100-1000 fold lower vs other species studied). This observation may have important implications for the use of experimental rabbit models especially in studies on the role of platelets in various pathological conditions including thrombosis and atherosclerosis.

Key words

Thrombosis - fibrinolysis - serpin - atherosclerosis - platelets

Full Text

References

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