Secretomes differ between peripheral blood and bone marrow-derived platelets

Abstract

Purpose: Platelet rich plasmas and bone marrow aspirates are commonly used in orthobiologics for their pro-proliferative and immunomodulating characteristics via platelet degranulation and cell secretions. While platelets are derived from megakaryocytes in the bone marrow, no attention has been paid to the potential benefits of bone marrow platelets and whether or not their contents differ from aging platelets in peripheral blood. The aim of our in vitro study was to characterize the difference in cytokines release from platelets derived from the peripheral blood and bone marrow over an extended time-course. Methods: In the present study, prepared leukocyte-poor peripheral blood-derived platelets in plasma (LPP) and leukocyte-poor bone marrow platelets in plasma (BMP) were derived from six donors, stimulated with calcium chloride, incubated at 37°C and sampled at Day 0, Day 3 and Day 6. At each time point, 15 growth and immunomodulatory factors were quantitated in LPP and BMP. Results: The results illustrate that platelets derived from the bone marrow have a unique secretome profile compared to those of peripheral blood. Of the 15 cytokines quantitated, we found significant differences in M-CSF, HGF, IL-4, IL-10, IRAP and Arginase-1 levels. Each of these cytokines have anti-inflammatory roles with important implications in monocyte polarization. Conclusions: Bone marrow-derived platelets may be useful as a stand-alone orthobiologic or as an effective adjunct to autologous cell therapies where anti-inflammatory and anabolic processes are desired especially with respect to monocyte function, such as in the treatment of osteoarthritis.