Effect of controlled hyperglycaemia on factor VIII concentrations in insulin dependent diabetes mellitus

Air pollution-associated procoagulant changes: the role of circulating microvesicles

BACKGROUND

Epidemiological studies suggest an association between exposure to particulate matter (PM) in air pollution and the risk of venous thromboembolism (VTE).

OBJECTIVES

To investigate the underlying pathophysiological pathways linking PM exposure and VTE.

PATIENTS AND METHODS

We assessed potential associations between PM exposure and coagulation and inflammation parameters, including circulating microvesicles, in a group of 233 patients with diabetes.

RESULTS

The numbers of circulating blood platelet-derived and annexin V-binding microvesicles were inversely associated with the current levels of PM(2.5) or PM(10), measured on the day of sampling. Recent past exposure to PM(10), up to 1 week prior to blood sampling, estimated at the patients' residential addresses, was associated with elevated high-sensitivity C-reactive protein (CRP), leukocytes and fibrinogen, as well as with tissue factor (TF)-dependent procoagulant changes in thrombin generation assays. When longer windows of past exposure were considered, up to 1 year preceding blood sampling, procoagulant changes were evident from the strongly increased numbers of red blood cell-derived circulating microvesicles and annexin V-binding microvesicles, but they no longer associated with TF. Past PM exposure was never associated with activated partial thromboplastin time (aPTT), prothrombin time (PT), or factor (F) VII, FVIII, FXII or D-dimers. Residential distance to a major road was only marginally correlated with procoagulant changes in FVIII and thrombin generation.

CONCLUSIONS

Increases in the number of microvesicles and in their procoagulant properties, rather than increases in coagulation factors per se, seem to contribute to the risk of VTE, developing during prolonged exposure to air pollutants.

Diabetic ketoasidosis is associated with prothrombotic tendency in children

Children and adolescents with type I diabetes mellitus (DM) may present with diabetic ketoacidosis (DKA), which is associated with significant morbidity and mortality. This study aimed to evaluate the hematological parameters at diagnosis (0th hour) and 96th hour after the initiation of treatment in children with DKA. Twenty-six children with DKA treated in Dicle University Faculty of Medicine between September 2002 and August 2003 were included in this study. General characteristics of the patients and hematological parameters (platelet count, white blood cell count, prothrombin time, partial thromboplastin time (PTT), bleeding time, coagulation time, protein C, protein S, antithrombin III, fibrinogen, D-dimer, factor VIII, factor IX, and factor X levels) at diagnosis (0th hour) and 96th hour after the initiation of treatment were determined. The mean age of the children (10 girls and 16 boys) was 9.15 ± 3.85 years (range: 4-15 years). DKA developed for the first time in 58.3% of these children and they had recently been diagnosed as DM. After hematological parameters at 0th hour were evaluated, increased platelet count, decreased PTT, low protein C, and high factor VIII levels were determined at diagnosis, indicating prothrombotic tendency. If the hematological parameters at 0th hour were compared with those at 96th hour; platelet count decreased, PTT increased, protein C and factor VIII levels turned to be normal at 96th hour. When all the results are considered together, children with DKA appeared to have a prothrombotic tendency. Although this tendency was not reflected in clinical findings in this study, it should be kept in mind that children with DKA are prone to the development of thrombosis and they need to be investigated for the possibility of thrombosis.

Plasma free N-terminal fibronectin 30-kDa domain as a marker of endothelial dysfunction in type 1 diabetes mellitus

The plasma free N-terminal fibronectin 30-kDa domain was measured in 44 type 1 diabetic patients and in 20 healthy subjects. A significantly raised mean concentration of a free N-terminal fibronectin 30-kDa domain was found in plasma of diabetic patients with proliferative retinopathy as compared with healthy persons (P less than 0.001). A positive correlation was observed between free N-terminal fibronectin 30-kDa domain and von Willebrand factor in plasma of all examined subjects (r = 0.62, P less than 0.01). A similar correlation was present between 30-kDa domain and albuminuria (r = 0.56, P less than 0.01). However, no relationship was found between fibronectin 30-kDa domain and control of diabetes as assessed by fructosamine concentration. The free N-terminal fibronectin 30-kDa domain may be used as a marker of actual endothelial cell dysfunction in diabetes.