Animal, Cellular & Molecular Models

July 13, 2003
08:00-12:00
Hall 5
The International Convention Center, Birmingham

Chairman: P. Jagadeeswaran, USA
Co-chairs: P. Carmeliet, Belgium; G. Johnson, USA; C. Kluft, The Netherlands;
T. Nichols, USA

Approximately 200 persons attended the meeting.  Presentations were made by ten speakers describing a variety of animal models.

Scientific meeting:

B. Furie (Boston) described a technique to observe in vivo thrombus formation in real time using confocal widefield microscopy. He demonstrated sequential incorporation of platelets, fibrin and tissue factor, identified by fluorescent-labeled specific antibodies that allowed three color displays, into thrombi in mouse vessels. This is a powerful technique for studying the sequential events in thrombus formation.

G. Johnson (Minneapolis) presented results of studies of the potential serotonin contribution to the cardiopulmonary toxicity of fenfluoramine. These studies were performed in canine model, which demonstrated decreased platelet serotonin, and increased plasma serotonin, resulting from decreased platelet uptake, and cardiac valve dysfunction. This model has potential utility for further study of cardiopulmonary toxicity induced by anorectic drugs that affect serotonin metabolism.

E. Rosen (South Bend) described in utero transplantation of fetal cells to rescue factor X null mice. Low levels of factor X expressed were sufficient to allow survival. The predominant site of localisation of the transplanted cells and their progeny was the liver although expression was demonstrated in other organs. This technique was projected to be useful for gene therapy.

S. Coughlin (San Francisco) presented the development of a PAR-4 knockout mouse that results in elimination of thrombin-induced platelet aggregation. Mice had prolonged tail bleeding times, but only a mild bleeding tendency. Using two different models (FeCl3 thrombosis model and thromboplastin induced pulmonary embolism model) he demonstrated a significant protection from thromboembolism by PAR-4 deletion.

P. Jagadeeswaran  (San Antonio) presented a comprehensive characterisation of zebrafish hemostatic pathways demonstrating all hemostatic pathways found in humans are present in zebrafish. He developed methods to screen for hemostasis defects and isolated several mutants such as victoria. He also showed that young thrombocytes initiate while mature thrombocytes propagate the arterial thrombus. This model should be useful in identifying novel hemostatic mutations in future.

T. Nichols (Chapel Hill) described the effects of intravenous injection of P. gingivalis on inflammatory parameters and atherosclerosis in normocholesterolemic pigs. Increased CRP, IgG to P.gingivalis and atherosclerosis predominantly composed of smooth muscle cells were noted in P. gingivalis injected pigs. Additional studies in hypercholesterolomic pigs are in progress.

C. Kluft (Leiden) reviewed human data regarding the role of fibrinogen in atherogenic disease. Overexpression of fibrinogen in apoE3 mice did not result in accentuation of atherosclerosis. Since fibrin is a component of atheromatous lesions further development of animal models to study the role of fibrinogen in atherosclerosis was suggested.

S. Emeis (Leiden) summarised data regarding current understanding of fibrin participation in mouse models of atherosclerosis. In afibrinogenemic mice fatty streak lesions were less prominent although the number and the composition of lesions were unaffected.  Further understanding of the contribution of fibrinogen to cardiovascular disease will require additional characterization of different forms of fibrinogen and strain specificity in mouse models.

E. Conway (Leuven) described studies of the role of endothelial survivin (an inhibitor of apoptosis) on angiogenesis. Fetuses lacking endothelial survivin showed extensive haemorrhage and had pericyte/endothelial cell abnormalities. These studies indicate survivin plays a role in vascular stability and integrity.

N. Mackman (La Jolla) described the generation of data on low tissue factor mice and illustrated blood borne tissue factor contributes to thrombus formation using bone marrow transplantation techniques. He analysed the role of TF in two different thrombosis models and observed a predominant contribution of vascular TF in one model and blood borne TF in the other model.

Business Meeting:

G. Johnson presented plans to review and analyze various methodologies useful in characterization of mouse hemostasis. Following the subcommittee decision made in Boston Dr. Johnson (USA) agreed to chair a working party composed of S. Lord (USA), A. Shet, (USA) M. Jirouskova (USA), S. Emeis (Netherlands), O. Matsuo (Japan), and E.M.Muchitsch (Austria) that will prepare a manuscript for the approval by Animal Model subcommittee to be submitted to the SSC for approval as an official communication at the Venice meeting 2004.