Platelet gel-released supernatant modulates the angiogenic capability of human endothelial cells.

BACKGROUND Platelet gel is used to facilitate wound healing in virtue of the growth factors released from activated platelets at the site of lesion, but little is known about the specific mechanisms underlying cellular repair. AIMS To evaluate, in vitro, cellular effects of different concentrations of platelet gel -released supernatant on endothelial cells. MATERIAL AND METHODS Platelet concentrate was produced at the Service of Immunohaematology and Transfusion of San Salvatore Hospital of L'Aquila, using multiple bags. Platelet gel was obtained by adding thrombin and calcium gluconate to the concentrates and then centrifuging to recover the supernatant. Human umbilical vein endothelial cells were isolated from umbilical cord veins and grown in appropriate conditions. To study their viability, cells were treated with different concentrations of supernatant and XTT assays were performed on the 3 days following treatment. Endothelial cell motility and invasiveness were assayed using modified Boyden chambers with filters coated with 0.1% gelatin (for the motility test) or with a thick layer of the reconstituted basement membrane Matrigel (for the invasion test). The supernatant, added at various concentrations to the lower compartment of the chamber, was used as an attractant. Umbilical cells were added to the upper compartment of the chamber. After 4 hours (for the motility test) or 6 hours (for the invasion test), filters were stained and the migrated cells in five high-power fields were counted. RESULTS When used at specific concentrations, platelet gel-released supernatant is able to induce proliferation and to stimulate motility and invasiveness of endothelial human cells. Higher concentrations induce a reversion of the stimulatory processes. CONCLUSIONS There is a large body of evidence indicating that platelets and their derivatives have the potential for a substantial therapeutic role in tissue regeneration. The results of this in vitro study highlight the need for an in-depth analysis of technical protocols for the most appropriate and effective use of platelet gel for in vivo applications.