Aspirin inhibits VEGF release and angiogenesis mediated by ADP or MCF-7 cell exposure. (A) VEGF concentration in the releasate of platelets (plts) with or without pretreatment with aspirin (asa) alone or with exposure to ADP (25μM) or MCF-7 cells. (B) Endothelial cell migration after exposure to the releasate from platelets pretreated with aspirin alone or before exposure to ADP or MCF-7 cells. (C) Capillary tube formation using releasate from platelets pretreated with aspirin alone or before exposure to ADP or MCF-7 cells. (D) VEGF concentration in the releasate of platelets from subjects who ingested aspirin alone or after exposure to ADP or MCF-7 cells. (E) Representative images of capillary tube formation using platelet releasate from subjects who ingested aspirin with or without exposure to ADP or MCF-7 cells. (F) Schematic of the balance of pro- and anti-angiogenic factors and how this is influenced by platelet activation. Specific factors can influence which proteins are released from platelet α granules resulting in an overall pro- or anti-angiogenic effect. As diagrammed, TXA2 activation results in inhibition of blood vessel growth and ADP or MCF-7 cell regulated activation results in promotion of blood vessel growth.
