CD34 and varicocele: Furthermore, our group evaluated the effects of PDRN alone and administration in experimental varicocele, demonstrating an increase in testicular angiogenesis mediated by the modulation of vascular endothelial growth factor (VEGF) -a [17] and CD-34 [18] and an inhibition of apoptosis proteins (IAPs), such as neuronal apoptosis inhibitory protein (NAIP) and survivin [33].