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Poly-L-histidine downregulates fibrinolysis
Arthur J Chu1, Suresh T Mathews
1Department of Surgery, School of Medicine, Wayne State University, Detroit, Michigan, USA. ajchu91@hotmail.com
Summary
Poly-L-histidine (PLH) significantly slows down urokinase (uPA)-dependent fibrinolysis by interfering with plasmin activity. This suggests a novel mechanism by which PLH impacts blood clot breakdown.
Area of Science:
- Biochemistry
- Hematology
- Molecular Biology
Background:
- Elevated histidine-rich glycoprotein is a risk factor for inherited thrombophilia.
- The precise mechanism of histidine-rich glycoprotein in thrombophilia is not fully understood.
Purpose of the Study:
- To investigate whether poly-L-histidine (PLH), mimicking the histidine-rich region, modulates urokinase (uPA)-dependent fibrinolysis.
- To elucidate the role of PLH in the regulation of fibrinolysis.
Main Methods:
- Utilized an in vitro model to monitor fibrin polymer formation and lysis.
- Assessed the effect of PLH on uPA- and plasmin-dependent fibrinolysis.
- Measured uPA amidolytic activity and plasmin formation.
- Investigated the impact of PLH on plasmin amidolytic activity.
Main Results:
- Poly-L-histidine (PLH) significantly downregulated uPA-dependent fibrinolysis.
- PLH did not inhibit plasminogen activation, uPA amidolytic activity, or plasmin amidolytic activity.
- PLH markedly delayed plasmin-dependent fibrinolysis when pre-incubated with plasmin or fibrinogen.
- Formation of a [plasmin-PLH-fibrin] complex was observed, significantly delaying fibrinolysis.
Conclusions:
- PLH interferes with fibrinolysis by forming a complex with plasmin and fibrin, thereby delaying clot breakdown.
- This study reveals a novel mechanism for PLH in modulating fibrinolysis, potentially relevant to thrombophilia.