Modifying Orthobiological PRP Therapies Are Imperative for the Advancement of Treatment Outcomes in Musculoskeletal Pathologies

Abstract

Autologous biological cellular preparations have materialized as a growing area of medical advancement in interventional (orthopedic) practices and surgical interventions to provide an optimal tissue healing environment, particularly in tissues where standard healing is disrupted and repair and ultimately restoration of function is at risk. These cellular therapies are often referred to as orthobiologics and are derived from patient's own tissues to prepare point of care platelet-rich plasma (PRP), bone marrow concentrate (BMC), and adipose tissue concentrate (ATC). Orthobiological preparations are biological materials comprised of a wide variety of cell populations, cytokines, growth factors, molecules, and signaling cells. They can modulate and influence many other resident cells after they have been administered in specific diseased microenvironments. Jointly, the various orthobiological cell preparations are proficient to counteract persistent inflammation, respond to catabolic reactions, and reinstate tissue homeostasis. Ultimately, precisely delivered orthobiologics with a proper dose and bioformulation will contribute to tissue repair. Progress has been made in understanding orthobiological technologies where the safety and relatively easy manipulation of orthobiological treatment tools has been demonstrated in clinical applications. Although more positive than negative patient outcome results have been registered in the literature, definitive and accepted standards to prepare specific cellular orthobiologics are still lacking. To promote significant and consistent clinical outcomes, we will present a review of methods for implementing dosing strategies, using bioformulations tailored to the pathoanatomic process of the tissue, and adopting variable preparation and injection volume policies. By optimizing the dose and specificity of orthobiologics, local cellular synergistic behavior will increase, potentially leading to better pain killing effects, effective immunomodulation, control of inflammation, and (neo) angiogenesis, ultimately contributing to functionally restored body movement patterns.

Keywords: angiogenesis; autologous orthobiologics; bioformulations; dosing; evolutionary medicine; immunomodulation; painkilling effects; platelet-rich plasma; platelets; platelet–leukocyte interactions.

Figure 1

Platelet granular storages and their content in non-activated platelets. Electron microscopic scanning pictures of a cluster of platelets, at original magnification ×10,000. In (A), non-activated platelets from a PRP vial (PE) are shown. The ill-defined grey bodies represent the α-granules, approximately 50–80/platelet. The opaque round bodies are the dense granules, ranging from 0–30/platelet, and grey string-like bodies are lysosomes [24]. Thin lines signify platelet cell membranes. In (B), disrupted cell membranes are visible as activated platelets have released their granular contents (Abbreviations: ADP: adenosine diphosphate; ATP: adenosine triphosphate; TNF: tumor necrosis factor; 5-HT: serotonin; vWF: von Willebrand Factor; PDGF: platelet-derived growth factors; TGF: transforming growth factor; VEGF: vascular endothelial growth factor; FGF: fibroblast growth factor EGF: epidermal growth factor; CTGF: connective tissue growth factor; HGF: hepatocyte growth factor; KGF: keratinocyte growth factor; IGF: insulin-like growth factor; TIMP: Tissue inhibitor of metalloproteinase; MMP: matrix metalloproteases; F: coagulation factor; β-TG: beta-Thromboglobulin; NAP: neutrophil-activating peptide; MIP: Macrophage inflammatory protein; SDF: stromal cell derived factor; C: complement protein; Ig: Immunoglobulin). Adapted and modified from Everts et al. [3].

Figure 2

Multicellular Density Separation after a Double-spin PRP Procedure. Graphical presentation of the cellular gravitational density separation using a 60 mL PurePRP-SP^® device (Used with permission from EmCyte Corporation, Fort Myers, FL, USA). After the first spin (A), the whole blood is sequestered in a top layer (plasma fraction), an intermediate thin layer (multicomponent buffy coat, including platelets and leukocytes), and a bottom layer consisting of RBCs. After the second spin (B), all cells are concentrated at the bottom of the second compartment of the PRP device. In (C), after a magnification of the second compartment after the second spin, the multicellular buffy coat stratum (grey layer on top of the RBCs). Further enhancement, (D) picture, indicates the representation following cellular gravitational density separation, according to the specific densities of the individual cells [94]. Caveat: note the overlap in the range of cellular densities of the various cell types.

Figure 3

Visual aspects after the First and Second spin of NP-PRP and NR-PRP Preparations. After the first centrifugation spin, no differences occur for NP-PRP (A) and NR-PRP first phase preparation (B). During this cycle, the unit of whole blood is sequestered in a platelet poor plasma (PPP) fraction, thin buffy coat layer, and a packed RBC layer. After the second spin, the plasma in the second device chamber is removed until the remaining volume in each device is in accordance with the total calculated treatment volumes for both bioformulations. Thereafter, the cells at the bottom of the chamber are resuspended with the remaining plasma. Laboratory data present the differences between the NP-PRP (C) and NR-PRP (D) fractions. Note, the broader RBC layer in the NR-PRP vial (D) when compared to the NP-PRP preparation (C). Furthermore, the NR-PRP buffy coat stratum on top of the RBCs is more noticeable (PurePRP-SP^® device, used with permission from EmCyte Corporation, Fort Myers FL, USA) (Abbreviation: TAP: total available platelets).

Figure 4

Description of Dosing and Bioformulations of the various injected Tissue Structures. Both, NP- and NR-PRP prepared volumes were transferred in smaller application syringes. The volumes in these syringes are corresponding with the calculations following the algorithm used, safeguarding platelet dose and bioformulations to treat the various tissue structures based of the pre-procedure treatment plan.

Figure 5

A comparative image of the right knee showing medial meniscus and MCL. In situation (A), 11 weeks after the procedure, the medial meniscus is visible following an intra-meniscal NR-PRP injection. In situation (B), the pre-treatment condition of the meniscus is visualized.