Supervisors info:
Πολίτου Μαριάννα, Αναπληρώτρια Καθηγήτρια, Ιατρική Σχολή, ΕΚΠΑ
Γιαλεράκη Αργυρή, Αναπληρώτρια Καθηγήτρια, Ιατρική Σχολή, ΕΚΠΑ
Κωνσταντόπουλος Κωνσταντίνος, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Summary:
Factor XII is a glycoprotein that initiates the intrinsic coagulation cascade and is one of the constituents of the contact system. Deficiency of factor XII is not associated with hemorrhage, doubting his role in normal hemostasis. However, he has been shown to contribute to thrombus stability and fibrinolysis, and it is still unclear whether his deficiency is a risk factor for thrombosis in humans. Furthermore, factor XII is participating in inflammatory reactions through complement activation and bradykinin production after the contact system initiating process. Thus, factor XII stands on the crossroad of inflammation and thrombosis.
Sickle cell disease, an inherited haemoglobinopathy, is due to a mutation in β-globin gene, resulting in structural change of hemoglobin under hypoxia and is a typical disease model where inflammation and thrombosis coexist. Red cell membrane changes lead to chronic hemolysis and complex interactions of red cells with platelets, leukocytes and vascular endothelium, with inflammatory molecule production and coagulation system activation, ultimately leading to microvascular obstruction, ischemia and organ damage.
The objective of this work was to evaluate the possible role of FXII in sickle cell disease. Levels of FXII were measured in 29 sickle cell disease patients and compared with those of healthy blood donors. Any association of FXII with certain clinical manifestations or with certain biological indexes of the disease was tested. For the purpose of this, full blood count and biochemical tests were done in sickle cell disease patients, along with coagulation tests, CRP measurement and measurement of C3 and C4 complement components.
Levels of FXII were significantly lower in patients with sickle cell disease compared to those of healthy blood donors, indicating activation of contact system in sickle cell disease. There was not any correlation between FXII and certain clinical manifestations of the disease, although significant correlations were found between FXII and fibrinogen, C3, C4 and nucleated red blood cells.
Overall, the findings of this study are indicative of activation of contact system and participation of FXII in inflammatory and hemolytic procedure of sickle cell disease.
Keywords:
Factor XII, Sickle cell disease, Contact system, Thrombosis, Inflammation
