scholarly journals Novel Mouse Hemostasis Model for Real-Time Determination of Bleeding Time and Hemostatic Plug Composition

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4177-4177
Author(s):  
Wolfgang Bergmeier ◽  
Raymond Piatt ◽  
Brian G. Petrich ◽  
Dougald Monroe ◽  
Nigel Mackman ◽  
...  

Abstract Introduction: Hemostasis is a rapid response by the body to stop bleeding at sites of vessel injury. Both platelets and fibrin are important for the formation of a hemostatic plug. Mice have been used to uncover the molecular mechanisms that regulate the activation of platelets and coagulation under physiological conditions. However, measuring hemostasis in mice is quite variable and current methods do not quantify platelet adhesion or fibrin formation at the site of injury. Methods: We describe a novel hemostasis model that uses intravital fluorescence microscopy to quantify platelet adhesion, fibrin formation, and time to hemostatic plug formation in real-time. Repeated vessel injuries of ~50-100µm in diameter were induced using laser ablation technology in the saphenous vein of mice. Results: Hemostasis in this model was strongly impaired in mice deficient in glycoprotein (GP)Ibα (IL4R/GPIb-tg) or talin-1 (talin1f/f PF4-Cre), important regulators of platelet adhesiveness. In contrast, the time to hemostatic plug formation was only minimally affected in mice defective in the extrinsic (tissue factor (TF)low) or the intrinsic (FIX-/-) coagulation pathways, even though platelet adhesion was significantly reduced. Interestingly, fibrin accumulation was markedly increased in lesions of talin1f/f PF4-Cre, IL4R/GPIb-tg and FIX-/- mice, while it was decreased in TFlow mice. These findings suggest that prolonged plasma exposure to TF leads to increased thrombin and fibrin generation in the surrounding tissue. A partial reduction of platelet adhesiveness using clopidogrel led to instability within the hemostatic plug, especially when combined with impaired coagulation in TFlow mice. Conclusions: In summary, we present a novel, highly sensitive method to quantify hemostatic plug formation in mice. This new model has several defining characteristics, including the use of intravital fluorescence microscopy to monitor the hemostatic process, the novel use of laser ablation technology to generate vascular lesions with a defined diameter, the ability to repeatedly disrupt the hemostatic process at the same site of injury, and the possibility to perform multiple injuries along the exposed saphenous vein. Based on its sensitivity towards platelet adhesion defects and its real-time imaging capability, we propose this model as an ideal tool to study the efficacy and safety of antiplatelet agents. Disclosures No relevant conflicts of interest to declare.

1968 ◽  
Vol 20 (03/04) ◽  
pp. 384-396 ◽  
Author(s):  
G Zbinden ◽  
S Tomlin

SummaryAn in vitro system is described in which adhesion of blood platelets to washed and tannic acid-treated red cells was assayed quantitatively by microscopic observation. ADP, epinephrine and TAME produced a reversible increase in platelet adhesiveness which was antagonized by AMP. With Evans blue, polyanetholsulfonate, phthalanilide NSC 38280, thrombin and heparin at concentrations above 1-4 u/ml the increase was irreversible. The ADP-induced increase in adhesiveness was inhibited by sodium citrate, EDTA, AMP, ATP and N-ethylmaleimide. EDTA, AMP and the SH-blocker N-ethylmaleimide also reduced spontaneous platelet adhesion to red cells. No significant effects were observed with adenosine, phenprocoumon, 5-HT, phthalanilide NSC 57155, various estrogens, progestogens and fatty acids, acetylsalicylic acid and similarly acting agents, hydroxylamine, glucose and KCN. The method may be useful for the screening of thrombogenic and antithrombotic properties of drugs.


2015 ◽  
Vol 30 (7) ◽  
pp. 500-500

The clinical significance of below-knee great saphenous vein reflux following endovenous laser ablation of above-knee great saphenous vein, by NS Theivacumar, RJ Darwood, D Dellagrammaticas, AID Mavor, MJ Gough, Phlebology DOI:10.1258/phleb.2008.008004, published February 2009; 24 (1): 17–20 . The authors would like to note the following correction to their article: One of the co-authors’ names was misspelled; it appears as “Dellegrammaticas”; however, it should be spelt “Dellagrammaticas”.


2017 ◽  
Vol 88 ◽  
pp. 25-33 ◽  
Author(s):  
Pattamon Teerapanich ◽  
Martine Pugnière ◽  
Corinne Henriquet ◽  
Yii-Lih Lin ◽  
Chia-Fu Chou ◽  
...  

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