TECHNICAL NOTESModifications of flow measurement to determine fibrin gel permeability and the preliminary use in research and clinical materialsHe, Shu; Cao, Honglie; Antovic, Aleksandra; Blombäck, MargaretaAuthor Information Coagulation Research, Department of Surgical Sciences, Karolinska Institutet, Stockholm, Sweden. This study was supported by funds from Novo Nordisk A/S, Maaloev, Denmark, the Magnus-Bergvall Foundation and the Swedish National Foundation for Preventing Stroke/Blood Vessel Disease in the Brain. Correspondence and requests for reprints to Shu He, M.D., Ph.D., Coagulation Research, Clinical Chemistry, L2-5, Karolinska Hospital, S-17176 Stockholm, Sweden. Tel: +46 8 51776871; fax: +46 8 312438; e-mail: email@example.com Received 12 December 2003 Revised 10 March 2004 Accepted 15 March 2004 Blood Coagulation & Fibrinolysis: January 2005 - Volume 16 - Issue 1 - p 61-67 Buy Abstract Our earlier investigations employing a flow measurement have yielded intriguing findings as to what governs the fibrin network porosity. To make the method suitable for use by more groups with various laboratory conditions, sample materials or study purposes, we simplified the essential equipment and thereby minimized the sample volume to 250 μl in comparison with the need for 3000 μl in the previous method. To assess whether the fibrin gel permeability depends on changes in thrombin generation potential and/or fibrinogen clotting property, different concentrations of thrombin with or without frozen–thawed platelets, serving as phospholipids, were used. The platelets and 0.05 IU/ml thrombin were added to plasma samples from patients with previous myocardial infarction. The fibrin gel permeability, expressed as Darcy constant (Ks), was decreased compared with that in controls, supporting findings about high risk of thromboembolism in this disease due to increases of thrombin activity and fibrinogen function. When 0.4 IU/ml thrombin was used in samples provided by 10 healthy individuals treated with acetysalicylic acid, Ks levels were increased during versus before therapy. Since almost no thrombin generation was found in the samples with the higher dose of exogenous thrombin, we considered that modifications in fibrinogen clotting property by acetysalicylic acid rendered the fibrin network more permeable. In summary, as the reproducibility remains satisfactory (coefficient of variation < 10%) despite aforementioned modifications in the equipment and reagents, any interested laboratory ought to be able to repeat the method. Assays of fibrin permeability in such a simple way may help to determine the fibrin clot stability in pathological/pharmacological studies, and probably serve as a tool to estimate thromboembolism risk in clinical materials, such as patients with cardiovascular diseases. © 2005 Lippincott Williams & Wilkins, Inc.