Correlation of levels of extracellular vesicles in peripheral and pulmonary blood plasma with pathological stages of lung cancer patients

Abstract

Background: Exosome concentration is known to be higher in cancer patients than in healthy individuals. In this study, we observed that the levels of exosomes differ in tumor-draining pulmonary blood and in peripheral blood in animal models and human subjects at different pathological stages of lung cancer. Methods: Ten rabbits and 40 humans formed the study cohorts. Blood was collected from a peripheral vein in all groups, and pulmonary blood was collected intraoperatively from all groups, except the healthy human controls. Quantitative analysis of exosomes was performed by nanoparticle tracking assay, CD63 enzyme-linked immunosorbent assay, and western blotting. Results: The peripheral blood of lung cancer-bearing animals and patients with lung cancer carried higher amounts of exosome than that from healthy controls (p < 0.01 and p < 0.001, respectively). Moreover, pulmonary blood from lung cancer-bearing animals and patients had significantly higher exosome levels, compared to preoperative peripheral blood (p < 0.01 and p < 0.0001, respectively). In patients, pulmonary exosome levels showed higher correlation with pathological stages of lung cancer than the peripheral exosome levels. Conclusions: Exosome levels increased with increasing grade of lung cancer, and this trend was more prominent in the pulmonary than in the peripheral blood.