Number of microvesicles in peripheral blood and ability of plasma to induce adhesion between phospholipid membranes in 19 patients with gastrointestinal diseases.

It was recently shown that the plasma protein-mediated attractive interaction between phospholipid membranes could in the budding process cause adhesion of the bud to the mother membrane [J. Urbanija, N. Tomsic, M. Lokar, A. Ambrozic, S. Cucnik, M. Kanduser, B. Rozman, A. Iglic, V. Kralj-Iglic, Coalescence of phospholipid membranes as a possible origin of anticoagulant effect of serum proteins, Chem. Phys. Lipids 150 (2007) 49-57]. Since in the in vivo conditions the budding of cell membranes leads to the release of microvesicles into the circulation, a hypothesis was put forward that the ability of plasma to cause adhesion between membranes supresses the microvesiculation process. In the present work, this hypothesis was tested in a population of 19 patients with gastrointestinal diseases. The number of microvesicles in peripheral blood of patients was determined by flow cytometry while the ability of plasma to cause adhesion between membranes was determined by adding patient's plasma to the suspension of giant phospholipid vesicles created by electroformation method, and measuring the average effective angle of contact between the adhered vesicles. Statistically significant negative correlations between the number of microvesicles and the average effective angle of contact (Pearson coefficient -0.50, p=0.031) and between the number of microvesicles per number of platelets and the average effective angle of contact (Pearson coefficient -0.64, p=0.003) were found, which is in favor of the above hypothesis. Patients with gastrointestinal cancer had larger number of microvesicles (difference 140%, statistical significance 0.033) and smaller average effective angle of contact (difference 20%, statistical significance 0.013) compared to patients with other gastrointestinal diseases.