Additionally, more than three injections of the autologous non-activated platelet-rich plasma (A-PRP) and calcium-activated platelet-rich plasma (AA-PRP) into scalps increased the activation of Bcl-2 protein (anti-apoptotic regulator), CD31 (Platelet endothelial cell adhesion molecule-1), VEGF and Akt signaling pathways, leading to improving the dermal papilla cells survival and proliferation during the hair cycle, and ultimately to improved hair count and density in both male and female patients with androgenetic alopecia [77,78,79,83,84,85,86,87]. This evidence concerns the gene PECAM1 and androgenetic alopecia.