High Concentrations of the Angiogenic Peptide VEGF-A in Seminal Fluid and its Association to Prostasomes.

BACKGROUND: Angiogenesis is the formation of new blood vessels by capillary sprouting from pre-existing vessels. This process is associated with increased expression of angiogenic factors like vascular endothelial growth factor (VEGF). The VEGF family consists of five members denoted VEGF-A, B, C, D and placenta growth factor (PlGF). Prostasomes are exosome-like extracellular vesicles existing in seminal plasma. The present study aimed at investigating the possible relationship between VEGF-A in seminal fluid and blood plasma and the prostasomal association of VEGF-A.

METHODS: Measurement of VEGF-A concentrations was carried out in seminal plasma from 40 males and in blood plasma from 40 male blood donors utilizing commercial ELISA kits. The prostasomal association of VEGF-A was investigated by flow cytometry.

RESULTS: We found highly elevated concentrations of VEGF-A in seminal fluid (median value 150000 pg/mL) compared with those of blood plasma. Flow cytometric analysis showed that VEGF-A is bound to the surface of prostasomes.

CONCLUSIONS: Prostasomes and seminal plasma contain the angiogenic factor VEGF-A in high concentrations exceeding that of blood plasma by 1000 times.