Diabetes is characterized by the existence of a thrombosis-prone condition, possibly related to hyperglycemia. However, the mechanism linking hyperglycemia to the activation of the coagulation cascade is still unclear. It has been recently suggested that diabetes is accompanied by increased oxidative stress. In this work, the possibility that oxidative stress may be involved in the hyperglycemia-induced coagulation activation has been evaluated. Prothrombin fragment 1 + 2 (F1 + 2), which represents a reliable marker of the amount of thrombin released in the circulation, has been chosen for studying thrombin formation in vivo. In nine type II diabetic patients and in seven healthy control subjects, matched for age and body mass index, three different experiments were performed: oral glucose tolerance test (OGTT), intravenous antioxidant glutathione (GSH) administration for 2 h, and OGTT plus intravenous GSH administration. Samples were drawn at -15 min and every 30 min from 0 to 180 min. During the OGTT, F1 + 2 significantly increased in both diabetic and healthy subjects. GSH administration during OGTT normalized this phenomenon. GSH administration alone significantly decreased F1 + 2 in diabetic patients, while no effect was observed in the normal subjects. These data suggest that hyperglycemia may induce thrombin activation, possibly inducing an oxidative stress, and that antioxidant GSH may counterbalance this effect.

Understanding of developmental haemostasis is critical to ensure optimal prevention, diagnosis, and treatment of haemorrhagic and thrombotic diseases in children. As coagulation test results are known to be dependent on the reagents/analysers used, it is recommended for each laboratory to define the age-dependent reference ranges by using its own technical condition. That study was carried out in seven centers to establish age-specific reference ranges using the same reagents and analyser. Plasma samples were obtained from 1437 paediatric patients from the following age groups: 15 days-4 weeks (n=36), 1-5 months (n=320), 6-12 months (n=176), 1-5 years (n=507), 6-10 years (n=132) and 11-17 years (n=262). Indication of coagulation testing was pre-operative screening for non-acute diseases in most cases. PT values were similar in the different age groups to those in adults, whereas longer aPTTs were demonstrated in the younger children. Plasma levels of all clotting factors, except for FV, were significantly decreased (p<0.0001) in the youngest children, adult values being usually reached before the end of the first year. The same applied to antithrombin, protein C/S, and plasminogen. In contrast, FVIII and VWF levels were elevated in the youngest children and returned to adult values within six months. The same applied to D-dimer levels, which were found elevated, particularly until six months of life, until puberty. These data suggest that most coagulation test results are highly dependent on age, mainly during the first year of life, and that age-specific reference ranges must be used to ensure proper evaluation of coagulation in children.

Retinal vein occlusion (RVO) is the second most common retinal vein disease and an important cause of blindness and visual morbidity. Systemic risk factors are commonly associated with RVO, while unclear it is the role of the thrombophilic and coagulation disorders. To evaluate "classic" and "emerging" risk factors, and to establish a good treatment for RVO. Fifty patients, 31 males and 19 females, with RVO were selected for our study. RVO patients were divided into two groups: those with central retinal vein occlusion (CRVO) and those with branch retinal vein occlusion (BRVO). All patients were subjected to an anamnestic investigation and were tested for thrombophilia, coagulation disorders and hyperlipidemia. Treatment and prophylaxis were evaluated. We have named "classic" the systemic risk factors associated with RVO and "emerging" those risk factors, haemostasis related, not clearly associated with RVO. RVO occurs more commonly in patients aged over 50. "Emerging" risk factors were more frequent in CRVO, "classic" in BRVO. Hyperhomocysteinemia is the most common "emerging" risk factor related to RVO. 71.4% of tested patients had hypercholesterolemia. Treatment with LMWH would appear to be safe and effective, but the small number of patients considered not allow us a definitive evaluation of its efficacy. Although our study has shown the correlation between RVO and the "emerging" risk factors, more studies are necessary to better know the real role of thrombophilic and coagulation disorders in this disease and to determine a specific protocol for the treatment and prophylaxis of RVO.

The study allowed us to define a uniform approach to LA testing and evaluation for laboratories employing the same methods.

It has been previously demonstrated that hyperglycaemia activates haemostasis; diabetes mellitus is considered a thrombosis-prone state. Acarbose, by inhibiting dietary carbohydrate absorption, reduces post-meal hyperglycaemia. In this study we evaluated the effect of post-meal hyperglycaemia on two markers of coagulation activation: prothrombin fragments 1 + 2 and D-dimer. Seventeen non-insulin-dependent diabetic patients maintained on diet therapy alone were randomly assigned to receive- with a cross-over study design-acarbose (100 mg orally) or placebo before a standard meal. Blood samples for measurement of plasma glucose, insulin, prothrombin fragments 1 + 2 and D-dimer were drawn at 0, 60, 120 and 240 min. After both placebo and acarbose, hyperglycaemia and hyperinsulinaemia which followed a standard meal were accompanied by a significant increase of plasma concentration of prothrombin fragments 1 + 2 and D-dimer in comparison to their baseline values. Acarbose administration significantly reduced the rise of glucose, insulin, prothrombin fragments 1 + 2 and D-dimer from 0 to 240 min in comparison to placebo. We conclude that post-meal hyperglycaemia, at the level reached by many diabetic patients on diet therapy alone, induces a coagulation activation. Acarbose, by decreasing post-meal hyperglycaemia, may be useful in reducing meal-induced activation of haemostasis in diabetic patients.