Frozen plasma specimens were thawed and centrifuged at 2,000×g for 10 min at 4°C and then at 10,000–14,000×g for 30 min at 4°C. Clarified plasma was passed through 0.22 µm-pore Millipore filter and used for exosome isolation by SEC performed using 1.5 cm×12 cm mini-columns (Bio-Rad, Hercules, CA, USA; Econo-Pac columns) packed with Sepharose 2B (Sigma-Aldrich, St. Louis, MO, USA). The column bed volume is 10 mL. Prior to applying clarified plasma, the column is washed with 20 mL of phosphate-buffered saline (PBS), and a porous frit is placed at the top of the gel to prevent its disturbance during subsequent elution with PBS. Clarified plasma (0.5–1.0 mL) was loaded onto the column and five 1 mL fractions corresponding to the void volume peak were collected. Fractions # 3, #4 and #5 were tested for protein content, morphology by transmission electron microscopy (TEM) and in functional assays. In preparation for western blots, the fractions were concentrated using 300,000 MWCO VivaSpin 500 Centrifugal Concentrators (Sartorius Corp, New York, NY, USA) by centrifugation at 5,000×g for 2–15 min, depending on the content. Supplementary Fig. 1 shows the schema for isolation of plasma exosomes by the mini-SEC method.