The Role of Leukocytes in Venous Thrombosis
Deep vein thrombosis is a complication and coexisting condition of many pathological situations and illnesses. Its sequel, pulmonary embolism, can develop into a life endangering situation. At the present time, there is no ideal diagnostic test or satisfactory treatment of this condition. The formulation and use of an animal model would increase our understanding of deep vein thrombosis and aid in the development of preventative measures. A model of DVT was developed. Nine cats used in the study were divided into experimental and control groups. All cats were anesthesized and local trauma was produced through exposure of the jugular vein. In the experimental group, the jugular vein was occluded for 72 hours before removal. In the control group, the vessel .as removed immediately after resection of adherent fat and connective tissue. The vein segments were examined for adherent cells, fibrin, and thrombi.. Leukocytes were the most abundant. cell type and appeared to be the first of the blood cell types to arrive. Leukocytes were often found in association with platelets, damaged endothelium, and thromhi. Platelets were adherent to exposed subendothelium and were also found in the fibrous network of thrombi. The etiology of DVT is believed to involve hypercoaqulation, a vascular factor, and venous stasis. Analysis of these three factors as they pertain to this model provided a proposed sequential understanding of thrombus formation. Experimental evidence suggests that adherent leukocytes are active in thrombus formation. Thrombus formation may be initiated through endothelial damage, secretion of leukotrienes, generation of procoagulant activity (PCA), production of thrombin-like ma t.e rial. (TLB), or through release of platelet activating factor (PAF). Stasis and tissue injury produced a reproducible model which may provide insight into the many cases of spontaneous DVT.