The Number of Platelets in Patient’s Blood Influences the Mechanical and Morphological Properties of PRP-Clot and Lysophosphatidic Acid Quantity in PRP

Abstract

The objectives of this study were to compare platelet-rich plasma (PRP) from patients with different concentrations of platelets and to assess the influence of these PRP preparations on human osteoblast (hOB) activity. In the literature, growth factors released by activated platelets have been considered responsible for the active role of PRP on bone regeneration but no specific role has been attributed to lysophosphatidic acid (LPA) as a possible effector of biological responses. In this study, patients were grouped into either group A (poor in platelets) or group B (rich in platelets). Clots from PRP fraction 2 (F2-clots), obtained with CaCl2 activation of PRP from the two groups, were compared macroscopically and microscopically and for their mechanical properties before testing their activity on the proliferation and migration of hOB. LPA was quantified before and after PRP fractioning and activation. The fibrin network of F2-clots from patients with a lower platelet concentration had an organized structure with large and distinct fibers while F2-clots from patients in group B revealed a similar structure to those in group A but with a slight increase in density. ELISA results showed a significantly higher plasma level of LPA in patients with a higher platelet concentration (group B) in comparison to those in group A (p < 0.05). This different concentration was evidenced in PRP but not in the clots. Depending on the number of platelets in patient’s blood, a PRP-clot with higher or lower mechanical properties can be obtained. The higher level of LPA in PRP from patients richer in platelets should be considered as responsible for the higher hOB activity in bone regeneration.

Variability in Platelet-Rich Plasma Preparations Used in Regenerative Medicine: A Systematic Review.

“…This study highlights usage of tissue speci c requirements parameters to de ne quality of the PRP. This is in line with other musculoskeletal in vitro studies which have highlighted the effect of speci c platelet derived factors on the osteogenic potential of stem cell lines [11,13,17]. A study involving 15 subjects by Bernardi et al, [14] also highlights the fact that freeze-thawing technique for PRP can damage platelet membranes and may potentially affect the quality of PRP, especially in terms of slow and sustained release of factors in vivo.…”

“…In vitro studies. Studies have measured platelet derived factors in PRP and were able to demonstrate speci c pro-osteogenic gene activation in MSC derived commercial human cell lines [11,13,17] and umbilical cord derived human autologous MSC cell lines [6]. The product was characterized in terms of platelet yield and growth factors, proliferation of the MSC's in cell lines, and activation of speci c genes was noted to measure the e cacy of the product.…”

“…Musculoskeletal system-based studies have demonstrated safety and e cacy of PRP in human studies [1,9]. We are now looking at the 4th generation approach where it is possible to design methods (Using engineering techniques) to maintain slow and sustained release of platelet derived factors in vivo [11,13].…”

Variability in Platelet-Rich Plasma Preparations Used in Regenerative Medicine: A Comparative Analysis

“…Musculoskeletal system-based studies have demonstrated safety and efficacy of PRP in human studies [ 1 , 17 ]. We are now looking at the 4th generation approach where it is possible to design methods (using engineering techniques) to maintain slow and sustained release of platelet derived factors in vivo [ 13 , 27 ].…”

Lysophosphatidic acid (LPA)-antibody (504B3) engagement detected by interferometry identifies off-target binding

“…, to albumin), and have dynamic biosynthesis and release (e.g. , with platelet degranulation [ 35 , 36 ]). As a result, LPA-targeting antibodies face the difficult task of removing actively and continuously produced LPA within not only signaling pools but also larger pools of structural membranes, vesicles, and other contributing compartments (e.g.…”