Platelet gel and factors determining its biological activity

A platelet gel (PG) derived from platelet concentrate (PC) is considered as a perspective therapeutic agent with hemostatic and regenerative properties. PG was obtained from PC separated from human peripheral blood by automatic apheresis by adding human thrombin (30 U/ml). We compared the proliferation of human mesenchymal stromal cells (MSCs) in vitro in the presence of PG and the dependence of gel density on excess of fibrinogen, the presence of calcium chloride, calcium gluconate, and aprotinin. PG was formed from CT in the presence of thrombin during 5–10 minutes. PG as gel-like fibrin membrane contained platelets and an admixture of leukocytes, and was capable to enhance the proliferation of MSCs in vitro. The presence of calcium gluconate (10 mg/ml) increased in the presence of PG the rate of MSCs proliferation in vitro. The presence of aprotinin in PG at a concentration of 10–1000 KIU/ml caused a dose-dependent decrease in the rate of gel biodegradation and did not affect the ability of PG to stimulate the proliferation of human MSCs in vitro.