Exosomes were enriched from 250 μl of PF and plasma using the ExoQuick kit (System Biosciences). Thrombin (2.5 μl) (500 U/mL, System Biosciences) per 250 μl plasma was added to remove the fibrin proteins. The samples were incubated at RT for 15 min while mixing, then centrifuged at 10,000 × g for 5 min at RT. PF and fibrin-depleted plasma were then filtered through a sterile 0.22 μm filter (Merck Millipore) into a fresh tube, and 75 μl ExoQuick solution was added. The samples were incubated for 30 min at 4°C, then centrifuged for 30 min at 1,500 × g and 4°C. The supernatant was removed, and following an additional centrifugation of the sample at 1,500 × g for 5 min at 4°C, the fluid was taken off and the pellet was re-suspended in 100 μl of sterile PBS. At the end of the process, the presence of exosomes in the preparation was confirmed by NTA, electron microscopy (see below) and western blotting. Protein concentrations were determined using Micro BCA protein assay (Thermo Fisher Scientific), and specified exosome doses used in experiments are based on these. miRNAs from exosomes were isolated using the miRNAeasy kit (Qiagen) (see above).