|English: Ribbon image of human PDGF receptor beta in complex with PDGF-B. This image was created using Pymol, based on 3MJG in the Protein Data Bank. (Photo credit: Wikipedia)
OK, Let us start our discussion on PRP with the Platelet Derived Growth Factor (PDGF) that served as a prototype growth factor for over 25 years. It plays an important role in blood vessel formation (angiogenesis) and it serves as an important mitogen for fibroblast through signalling pathways modulating cell cycle. Both these effects may be beneficial in skin rejuvenation. Though its overexpression has been linked to various fibrotic disorders and malignancies, it may not be important as far as PRP is concerned. However fibrotic skin disorders like scleroderma should be an important contraindication for PRP. Here is a summary of PDGF from SLISE.