Only minor changes in thrombin generation of children and adolescents with type 1 diabetes mellitus - A case-control study.

BACKGROUND: Micro- and macrovascular diseases are frequent complications in patients with diabetes. Hypercoagulability may contribute to microvascular alterations. OBJECTIVE: In this study, we investigated whether type 1 diabetes in children is associated with a hypercoagulable state by performing a global function test of coagulation - the thrombin generation assay. SUBJECTS: 75 patients with type 1 diabetes aged between 2 and 19years were compared to an age-matched healthy control group. Diabetes patients were divided into high-dose and low-dose insulin cohorts with a cut-off at 0.8Ukg-1d-1. METHODS: Measurements were performed with platelet poor plasma using Calibrated Automated Thrombography and 1 pM or 5 pM tissue factor. Additionally, we quantified prothrombin fragments F1+2, thrombin-antithrombin complex, prothrombin, tissue factor pathway inhibitor, and antithrombin. RESULTS: Patients with type 1 diabetes exhibited a significantly shorter of lag time as well as decreased thrombin peak and endogenous thrombin potential compared to control subjects with 5 pM but not with 1 pM tissue factor. In high-dose insulin patients peak thrombin generation was higher and time to peak shorter than in low-dose patients. Thrombin-antithrombin complex was decreased in patients with type 1 diabetes, whereas prothrombin fragments F1+2 was comparable in both groups. Thrombin generation parameters did not correlate with parameters of metabolic control and the duration of diabetes. CONCLUSIONS: Taken together, we found only minor changes of thrombin generation in children and adolescents with type 1 diabetes which - in contrast to type 2 diabetes - do not argue for a hypercoagulable state.

Low endogenous thrombin potential in trained subjects.

INTRODUCTION: A paradox seems to exist: exercising leads to clotting activation in conventional clotting tests, but exercising persons have a low risk of thrombosis. In this study we tried to evaluate the effect of exercise performance status on in vitro plasma thrombin generation, which represents an overall function test of hemostasis. MATERIALS AND METHODS: We compared 56 trained subjects to 98 healthy age matched sedentary volunteers. Blood samples were analyzed for thrombin generation using calibrated automated thrombography. Microparticles were quantified using ELISA. Additionally prothrombin fragments 1 + 2, thrombin-antithrombin complex, tissue factor pathway inhibitor, antithrombin and prothrombin were measured. The group of the trained subjects performed an incremental cycle-ergometer exercise test after taking the blood sample. RESULTS: A significantly lower endogenous thrombin potential was observed in the group of the trained subjects compared to the sedentary individuals (p = 0.007). Microparticles (ELISA) were significantly lower in the trained subjects compared to the sedentary subjects (p = 0.001). Prothrombin fragments 1 + 2 (p < 0.001) and thrombin-antithrombin complex (p = 0.01) were significant higher in the trained subjects and antithrombin (p = 0.02) as well as prothrombin (p < 0.0001) were significantly lower in this group, whereas tissue factor pathway inhibitor values did not show significant differences. Both maximal and submaximal power output was significantly negatively related to endogenous thrombin potential (r = -0.43, r = -0.45) and thrombin peak (r = -0.44, r = -0.42). CONCLUSIONS: Trained subjects have a lower endogenous thrombin potential than sedentary subjects possibly explaining the lower incidence of thrombosis in this group despite a higher acute clotting activation during strenuous exercise.

Thrombin generation before and after multicomponent blood collection.

BACKGROUND: Apheresis technology has made tremendous progress up to the development of automated blood component collection, which offers increased efficiency in donor blood use, but the concern about the contact of donor blood with artificial surfaces remains. Activation of the hemostatic system is a major issue in this context and is controversial. The aim of this study was to estimate the effect of apheresis on continuous thrombin generation (TG), representing a new tool to examine the overall function of the plasmatic clotting system. STUDY DESIGN AND METHODS: Twenty-six voluntary blood donors, fulfilling the law requirement for apheresis donation, participated in the study. Two units of platelets (6 x 10(11)) and 1 unit of red cells (250 mL; hematocrit level, 80%) were collected using two types of cell separators (Amicus, Fenwal, Inc.; and Trima Accel, Gambro BCT). Each donor underwent collection on both apheresis systems with at least 8 weeks in between. Samples of blood were collected before, immediately after, and 48 hours after apheresis. TG was measured using a slow fluorogenic substrate by means of calibrated automated thrombography (CAT). RESULTS: CAT data changed only slightly, and no significant changes were seen before, immediately after, and 48 hours after apheresis (p > 0.05). The variables did not differ significantly between the two different apheresis systems (p > 0.05). CONCLUSION: Using a CAT-based technique, no change in variables of continuous TG were observed, suggesting that multicomponent blood collection did not lead to severe alterations in the hemostatic system of the donors.