[Expression of von Willebrand's disease in endothelial cord cell from a type 1 patient. Discrepancies between clinical manifestations and laboratory tests].

PURPOSE

The reactivity of subendothelium generated by endothelial cells attained from the umbilical cord of a newborn girl from a patient with type I von Willebrand's disease was evaluated.

MATERIAL AND METHODS

Platelet adhesiveness was assessed by means of "ex vivo" blood perfusion systems (shearing coefficients from 300 to 1,300 s-1), on umbilical artery subendothelium and over the extracellular matrix (ECM) generated by cultured endothelial cells attained from the umbilical cord of a newborn baby from a type I von Willebrand mother.

RESULTS

By means of an ELISA technique, a significant reduction of both the vWF secreted into the culture (p < 0.05) and of that associated with ECM (p < 0.05) was noticed. The two subendothelial surfaces examined supported a lesser extent of platelet adhesion than the control surfaces from healthy individuals in the perfusion tests at 1,300 s-1 (p < 0.05). The experimental results did not agree with the lack of clinical manifestations and laboratory abnormalities in the propositus at age 3.

CONCLUSIONS

These findings suggest that the endothelial cells cultured from the tissues of a newborn baby from a type I von Willebrand woman expressed less vWF, at the same time confirming the importance of vWF bound to connective tissue in sustaining platelet adhesion. The data attained here illustrate the complex model of inheritance of moderate von Willebrand's disease, along with the technical limitations of cell culture studies. Such observations must be borne in mind whenever any experimental approach is performed with material attained from ill-differentiated tissues such as the umbilical cord vein.