VEGF-A165 is the predominant VEGF-A isoform in platelets, while VEGF-A121 is abundant in serum and plasma from healthy individuals

by Munekazu Yamakuchi, Masashi Okawa, Kazunori Takenouchi, Aryal Bibek, Shingo Yamada, Keiichi Inoue, Kazuhiko Higurashi, Akito Tabaru, Kiyonori Tanoue, Yoko Oyama, Sadayuki Higashi, Chieko Fujisaki, Hideaki Kanda, Hiroto Terasaki, Taiji Sakamoto, Yoshiharu Soga, Teruto Hashiguchi

Vascular endothelial growth factor A (VEGF-A) plays pivotal roles in regulating tumor angiogenesis as well as physiological vascular function. The major VEGF-A isoforms, VEGF-A121 and VEGF-A165, in serum, plasma, and platelets have not been exactly evaluated due to the lack of the appropriate assay system. Antibodies against human VEGF-A121 and VEGF-A165 (hVEGF-A121 and hVEGF-A165) were successfully produced and Enzyme-Linked ImmunoSorbent Assay (ELISA) for hVEGF-A121 and hVEGF-A165 were separately created by these monoclonal antibodies. The measurement of recombinant hVEGF-A121 and hVEGF-A165 by the created ELISA showed no cross-reaction between hVEGF-A121 and hVEGF-A165 in conditioned media from HEK293 cells transfected with either hVEGF-A121 or hVEGF-A165 expression vector. The levels of VEGF-A121 and VEGF-A165 in serum, plasma, and platelets from 59 healthy volunteers proved that VEGF-A121 level was higher than VEGF-A165 in both plasma and serum in all the cases. VEGF-A121 or VEGF-A165 in serum represented higher level than that in plasma. In contrast, the level of VEGF-A165 was higher than VEGF-A121 in platelets. The newly developed ELISAs for hVEGF-A121 and hVEGF-A165 revealed different ratios of VEGF isoforms in serum, plasma, and platelets. Measuring these isoforms in combination provides useful information as biomarkers for diseases involving VEGF-A121 and VEGF-A165.