ABSTRACT
Microvesicles (MVs) are membrane – enclosed nanoparticles which are created in the budding process of cell membranes. As they contain the constituents of the mother cell and are more or less free to move with circulation, they present potential biomarkers of physiological and patophysiological state of the organism. The knowledge on MVs is still rudimentary while methods of their determination are not yet standardized and are at the present state unusable in clinical practice. Within this work we were pursuing clinical relevance of MVs isolated from peripheral blood. Specificaly, we studied differences in concentration of MVs in isolates from blood of patients with gastrointestinal cancer, other gastrointestinal diseases and healthy subjects. We studied the post - prandial effect on the concentration of MVs in isolates in relation to blood cholesterol. Our study included 28 patients with gastrointestinal cancer, 24 patients with other gastrointestinal diseases and 156 healthy subjects. MVs were isolated by centrifugation and washing of samples, counted by flow cytometer and imaged by scanning electron microscope. Concentration of blood cholesterol was determined by enzymatic methods. We found that the concentration of MVs is considerably and statistically significantly increased in patients with gastrointestinal cancer with respect to patients with other gastrointestinal diseases (for 37 %, p = 0.012) and with respect to healthy subjects (for 48 %, p = 0.0002). We found a considerable (50 %) and statistically significant (p = 0.010) post – prandial increase of the concentration of MVs in blood isolates of healthy subjects which was negatively correlated with post – fasting concentration of blood cholesterol (p = 0.035). It turned out that the method of isolation of MVs from blood is sensitive to the temperature and dynamics of isolation. The concentration of MVs was higher while their average size was smaller when the temperature during the isolation was lower. It is indicated also from the size and shape of particles found in the isolated material and imaged by the electronic microscope that an important pool of MVs is created in vitro, after the blood sampling in the isolation process. As our results show that the concentration of MVs is connected to the clinical status, isolated MVs, albeit created after the blood sampling, present a clinically relevant parameter which reflects properties of cells from which they derive.