Platelet-Rich Plasma in Bone Regeneration: Engineering the Delivery for Improved Clinical Efficacy

Abstract

Human bone is a tissue with a fairly remarkable inherent capacity for regeneration; however, this regenerative capacity has its limitations, and defects larger than a critical size lack the ability to spontaneously heal. As such, the development and clinical translation of effective bone regeneration modalities are paramount. One regenerative medicine approach that is beginning to gain momentum in the clinical setting is the use of platelet-rich plasma (PRP). PRP therapy is essentially a method for concentrating platelets and their intrinsic growth factors to stimulate and accelerate a healing response. While PRP has shown some efficacy in both in vitro and in vivo scenarios, to date its use and delivery have not been optimized for bone regeneration. Issues remain with the effective delivery of the platelet-derived growth factors to a localized site of injury, the activation and temporal release of the growth factors, and the rate of growth factor clearance. This review will briefly describe the physiological principles behind PRP use and then discuss how engineering its method of delivery may ultimately impact its ability to successfully translate to widespread clinical use.

A Systematic Assessment of the Use of Platelet-Rich Plasma in Spinal Fusion

“…40 PRP may also be used in an unactivated liquid form, with eventual activation upon exposure to collagen type I in vivo. 49 This method may be beneficial as bioactive factor release would not occur until the PRP formulation is placed in the targeted location, though further work is required to better characterize this approach.…”

“…23 As described in further detail in a recent review, platelets release additional factors that could augment spinal fusion. 49 For instance, adhesive proteins, such as fibrinogen and von Willebrand factor, as well as lipids, may enhance cellular adhesion and chemotaxis. 49 The released factors play a role in wound healing and many have been shown to enhance parenchymal cell proliferation for tissue regeneration.…”

“…49 For instance, adhesive proteins, such as fibrinogen and von Willebrand factor, as well as lipids, may enhance cellular adhesion and chemotaxis. 49 The released factors play a role in wound healing and many have been shown to enhance parenchymal cell proliferation for tissue regeneration. Therefore, the goal of PRP therapy in spinal surgery is localized delivery of these factors to enhance spinal fusion.…”

Characterization of Leukocyte-platelet Rich Fibrin, A Novel Biomaterial

“…These benefits are attributed to the release of a variety of peptide growth factors from the alpha-granules of platelets upon activation 1 . Platelet concentrates (PC) were seen as a practical way to deliver growth factors 2 and its use was driven by commercial interests rather than research characterization 3 . In fact, PCs are difficult to characterize unlike homogenous and defined pharmacological preparations, they are a potpourri of signaling molecules and blood cells (platelet and leukocytes) entrapped within a fibrin matrix.…”

How to use BMP-2 for clinical applications? A review on pros and cons of existing delivery strategies

“…However, despite the efficacy of PRP in in vitro and in vivo scenarios, its use and delivery in terms of bone regeneration have yet not been optimized. A significant drawback of such preparations is that optimal doses for administration as well as the identity of the active substances within the concentrates are largely unknown [13].…”