Platelet-rich plasma (PRP) therapies and treatment protocols have evolved immensely over the past 20 years. Through laboratory, experimental, and clinical research, followed by, more recent, meta-analysis's, physicians, medical practitioners, and scientists have developed a better understanding of PRP bio-cellular physiology. Especially with regard to the functions of the specific biological components present in the platelet secretome1, and other plasma constituents, affecting PRP treatment outcomes when used in regenerative medicine therapies.

To optimize outcomes, based on patient specific underlying conditions, and tissue type, the practitioner needs to have a clear understanding on when to use which specific PRP protocols, in order to achieve desired regenerative and tissue repair effects, when PRP technology is employed.

The functional design of existing PRP processing systems, with the subsequent final PRP production, varies tremendously. These differences in PRP characteristics have been recognized in the literature2,3. Most PRP system technology is often based on antiquated device system PRP preparation protocols, the use of outdated science, a lack of solid research to show proof of concept of a newly developed product, absence of a full biological mind-set, and a too simplified view on the true regenerative capacities of all the PRP constituents. The consequential effects are that PRP treatments show little, or even no therapeutic effects, and sometimes deleterious effects have been reported, albeit these systems have not been adapted to meet current research findings.

EmCyte PurePRP® System is currently in its 3rd generation with PurePRP® Supraphysiologic.  It's design and performance characteristics are solidly based on intense and current research, meeting the needs in modern, therapeutic, regenerative medicine. The PRP design characteristics are centered on up-to-date medical and scientific studies, ensuring that physicians have the greatest chance at optimizing the efficacy of their patients' treatment outcomes, based on the capability of preparing different condition specific bio-cellular compositions.

From: Everts, PAM, Jakimowicz, v Beek M, et al. European Surg Res. 2007; 39: 199-2007.

PRP bio-cellular formulations, with leukocyte and erythrocyte composition.

As several other systems, EmCyte PurePRP® System is an FDA cleared, CE marked and 100% closed PRP processing system, hence eliminating the risks for contamination, contributing to improved sterility handling.

One of the major differences between EmCyte's PurePRP® system and competing devices is its versatility and flexibility, enabling the production of 2 different PurePRP® formulations, while maintaining supra-physiologic platelet concentrations of greater than 7 times baseline, in a standardized volume of 7mL of plasma. Depending on the physician's preference, the final volume can be altered to serve more treatment protocols, with varying platelet concentrations.

EmCyte PurePRP® neutrophil-poor protocol entails a double spin centrifugation protocol.  At the completion of this protocol, 98% of pro-inflammatory neutrophilic granulocytes are eliminated, and thus not present in the final PRP product. Furthermore, this protocol attains a significant high yield in monocytes, up to 6 times the baseline values.  Additionally, the red blood cell (RBC) content is a significantly reduced (99%) in the final PRP product, while maintaining a supra-physiologic platelet concentration.

EmCyte PurePRP® neutrophil-rich protocol, has also low erythrocyte concentrations, but the PRP is enriched with neutrophilic granulocytes. This protocol can be used when a significant inflammatory reaction is desired, in order to facilitate a strong leukocytic chemotaxis, to induce a phagocytic response, followed thereafter by a tissue regenerative activity. Recent evidence indicates the application for a leukocyte rich PRP for tendon regeneration, and to induce bone growth4-6.

The Clinical Relevance of Neutrophilic Granulocytes in PRP

Excessive neutrophil delivery can create potential for persistent inflammation and progression of joint damage, with the risk of directly inflicting damage to synoviocytes, bone, and cartilage via the secretion of proteases and toxic oxygen metabolites. Furthermore, increased inflammation is induced through antigen presentation and secretion of cytokines, chemokines, prostaglandins and leukotrienes7.

While neutrophils can be desirable in certain instances of treatment, chronic wound care (functioning to destroy and clear bacteria from the wound bed), within certain types of open surgery, or within specific protocols that require higher levels of, and more long-term periods of inflammation. However, recent evidence suggests that PRP intra-articular (OA), and intra-discal injections (DDD), should be neutrophil free8-10.

The Importance of High Monocyte Concentrations in PRP

Monocytes are non-inflammatory white blood cells and are the precursor to macrophages.  Macrophages are important cells of the immune system that, similar to neutrophils, are formed to fight infection, or engulf accumulating damaged or dead cells. Unlike neutrophils, monocytes do not lead to a prolonged inflammatory condition, but have been found to play important roles in tissue healing. Macrophage phenotype type M1 is responsible producing several inflammatory cytokines which support host defense through pathogen clearance, necrotic tissue clearance reactive oxygen species. Furthermore, M1 phenotypes produce growth factors such as VEGF and FGF.  The M2 macrophage phenotype have anti-inflammatory capacities, and generate precursors for collagen and fibroblast stimulating factor, thus supporting their role in extracellular matrix deposition. Generally, the plasticity of monocytes is dependent on the micro-environment in which they are present. Monocytes and macrophages release additional pro-regenerative growth factors that lead to neovascularization, proliferation of myogenic precursor cells, and stimulating the activity of satellite cells11,12. EmCyte PurePRP® is able to achieve much higher monocyte yields than other available systems13.

The Importance of RBC Removal in PRP Treatment Protocols

RBC's have been shown to cause degeneration and apoptosis of chondrocytes and synoviocytes when coming into contact with them; this can impede restoration of proteoglycan synthesis, leading to cartilage degeneration, and ultimately joint destruction14,15. In an experimental study, it was postulated that erythrocytes inhibit ligament fibroblast proliferation in a collagen scaffold. This finding might indicate the need for further research potential negative effects in MSK applications with PRP containing erythrocytes12. When erythrocytes lyse, hemoglobin willcause oxidative destruction in the vasculature and in exposed tissues13, contributing to significantly increased inflammation, post injection flares, and pain. Any PRP, containing erythrocytes, will lead to an increase in injectate viscosity, increasing injection difficulty, and reduces injection site tissue saturation. EmCyte PurePRP® neutrophil poor formulation has less than 1% RBCs contained in the final injectable when processed properly.

Physicians should have complete control over their, different, PRP formulations, with or without the inclusion of neutrophils, avoiding erythrocyte contamination. Furthermore, as indicated by recent literature, a high yield of monocytes, with their unique plasticity to function in any specific niche to support regenerative processes. However, when compared to EmCyte PurePRP® system technology, the majority of other existing PRP devices do not permit full manual control, or adjustment levels to control the presence of RBC's, neutrophils, and the production of high monocytes, and platelet concentrations. In most instances, these systems deliver high RBC's & neutrophil counts, combined with minimal monocytes yields from baseline values, and low, to very low, platelet concentrations. Devices that attempt to "remove" RBC's from the buffy coat, or utilize lab gel to separate RBC's, do so at the sacrifice of an extremely large number of platelets.

References: All articles are available upon request.

1.The platelet proteome.

Senzel L., Gnatenko D, Bahou W. ;Curr Opin Hematol. 2009; 16 (5): 329-333.

2.Not every PRP-gel is born equal. Evaluation of growth factor availability for tissues through four PRP-gel preparations: Fibrinet, RegenPRP-Kit, Plateltex and one manual procedure.

Mazzucco, L., Balbo, V., Cattana, E., et al. Vox Sang, 2009: 97, 110-118.

3.Differences in platelet growth factor release and leucocyte kinetics during autologous platelet gel formation.

Everts, P. A.; Hoffmann, J.; Weibrich, G.; Mahoney, C. B.; Schonberger, J. P.; van Zundert, A. and Knape, J. T.; Transfus Med. 2006: 16, 363-368.

4. The Effectiveness of Platelet-Rich Plasma in the Treatment of Tendinopathy. A Meta-analysis of Randomized Controlled Clinical Trials.

Fitzpatrick J., Bulsara M., Zheng M.; American Journal of Sports Medicine. 2016; 45, No. 1.

5. Platelet leukocyte gel facilitates bone substitute growth and autologous bone growth in a goat model.

Everts, PA, Delawi D, Brown Mahoney Ch., van Erp A, et al.; J Biomed Mater Res A. 2010: Feb;92(2):746-53

6.The crucial role of neutrophil granulocytes in bone fracture healing.

Kovtun A., Bergdolt S., Wiegner R., et al. ; Europ Cells and Materials. 2016: 32; 152-162.

7. Neutrophil function in inflammation and inflammatory diseases.

Wright, H. L., Moots, R. J., Bucknall, R. C., Edwards, S. W.; Rheumatology. 2010: 49(9), 1618-1631.

8. Effect of two different preparations of platelet-rich plasma on synoviocytes.

AssirelliE., Filardo G., MarianiE., Kon E., et al.; Knee Surg Sports Traumatol Arthrosc. 2015: 23:2690–2703.

9.Leukocyte-poor PRP application for the treatment of knee osteoarthritis.

Filardo G., Kon E., Matteo B., et al. Joints. 2013: 1 (3): 112-120.

10. Platelet-rich plasma injections for lumbar discogenic pain: A preliminary assessment of structural and functional changes.

Navani A, Hames A. ;Techniques in Regional Anesthesia and Pain Management. 2015; 19; 38-44.

11. Monocyte and Macrophage Plasticity in Tissue Repair and Regeneration.

Das, A., Sinha, M., Datta, S., et al.; American Journal of Pathology. 2015: 185(10), 2596-2606.

12. Monocytes and macrophages in tissue repair: Implications for immune-regenerative biomaterial design.

Ogle, M. E., Segar, C. E., Sridhar, S.,Botchwey, E. A. ; Experimental Biology and Medicine. 2016: 241(10), 1084-1097

13. White Paper Report 515, Research Study: Comparison of EmCyte GS30-PurePRP® II, EmCyte GS60-PurePRP® II, Arteriocyte MAGELLAN, Stryker REGENKIT®THT, and ECLIPSE PRP. Cambridge, MA: US.

Mandle, R. Bioscience Research Associates. (2016).

14. Short-Term Exposure of Cartilage to Blood Results in Chondrocyte Apoptosis.

Hooiveld, M., Roosendaal, G., Wenting, M.,et al. ; American J. of Pathology. 2003: 162(3), 943-951

15. The Effect of Platelet-Rich Plasma Formulations and Blood Products on Human Synoviocytes: Implications for Intra-articular Injury and Therapy. Braun, H. , Kim, H., Chu, C. , Dragoo, J. L.; American J. Sports Med. 2014: 42(5), 1204-1210.