Seminal prostasomes inhibit the angiogenesis activity of rat aortic rings

Prostasomes are organelles secreted by prostatic epithelial cells, and are believed to have a role in fertility and prostatic disease. They are known to influence sperm motility and the acrosome reaction, and are thought to have a role in cell transformation, immunosuppression, proliferation, facilitation of local invasion, and angiogenesis. Previously, we have demonstrated the inhibitory effect of prostasomes derived from human semen on angiogenesis using HUVEC cells grown on matrigel. In this study, we use the rat aortic ring assay system, arguably a closer reflection of the in vivo situation. Quantification was by a spectrophotometric method, and underlying mechanisms assessed. Prostasomes demonstrated a clear inhibition of angiogenesis, and this effect persisted after heat treatment of prostasomes to denature protein. This fits with other known effects of prostasomes known to be due to the membrane lipid component, which is unusually high in sphingomyelin and cholesterol.