Angiogenic effect of platelet-rich plasma combined with gelatin hydrogel granules injected into murine subcutis.

Platelet-rich plasma (PRP), which contains highly concentrated platelets, is produced by centrifuging whole blood. It is a safe and readily available source of a wide range of growth factors necessary for angiogenesis. Gelatin hydrogel granules have been designed and prepared for the controlled release of many growth factors. The angiogenic effect of human PRP was examined in vitro, and the effect of its subcutaneous injection with gelatin hydrogel granules into murine subcutis was evaluated. Human PRP was prepared using a double-spin method. The concentration of growth factors and the platelet count were examined in PRP and in vitro, and the angiogenic activity of human umbilical vein endothelial cells (HUVECs) in co-culture with human dermal fibroblast cells (NHDFs) in the presence and absence of PRP was evaluated. Then, in vivo, PRP, either free or with gelatin hydrogel granules, was injected subcutaneously into tiebacks on mice. Using a microscope and Kurabo angiogenesis image analyser software, the area containing newly formed capillaries was evaluated histologically and the microvascular network score was calculated. PRP was shown to contain high concentrations of PDGF, VEGF and TGFβ and had an angiogenic effect on the co-culture system. PRP with gelatin hydrogel granules significantly enlarged the area containing newly formed capillaries and promoted the microvascular network in murine subcutaneous tissue. PRP encapsulated in gelatin hydrogel microspheres shows promise for enhancing angiogenic effects in murine subcutis and could represent a potential therapeutic combination for the treatment of ischaemic disorders.