Characterization of Growth Factors, Cytokines and Chemokines in Bone Marrow Concentrate and Platelet Rich Plasma: A Prospective Analysis

Abstract

Objectives: Autologous platelet-rich plasma (PRP) and bone marrow concentrate (BMC) are orthobiologic therapies with numerous growth factors and cytokines. Mesenchymal stem cells (MSCs) are also present in BMC; however, comprise a very limited component of the available monocytes. Other clinically relevant factors and cytokines, including interleukin-1 receptor antagonist (IL-1Ra), are implicated in the anti-inflammatory and regenerative processes. Prior to optimizing the clinical utility of PRP and BMC as a combined or monotherapy, an improved understanding of the components and respective concentrations is necessary. The purpose of this study was to prospectively measure and compare anabolic, catabolic, anti-inflammatory and pro-inflammatory factors, proteins and cytokines present in bone marrow aspirate (BMA), BMC, whole blood, leukocyte poor (LP)-PRP and leukocyte rich (LR)-PRP from samples collected and processed concurrently from patients presenting for elective knee surgery. Methods: A total of 31 patients presenting for elective knee surgery were prospectively enrolled over a three-week period. Whole blood from peripheral venous draw and BMA from the posterior iliac crest were immediately processed using centrifugation and manual extraction methods to create LR- and LP-PRP and BMC, respectively. BMA, BMC, whole blood, LR-PRP and LP-PRP samples were immediately assayed and analyzed to measure factor and cytokine concentrations. We strictly adhered to the minimum reporting requirements for biological outcomes (MIBO). An a priori power and sample size calculation was performed. We conservatively assumed a Bonferroni correction among all 10 pairwise comparisons, two-tailed testing, and an overall alpha level of 0.05. Eighteen subjects was sufficient to detect this magnitude of effect size with 80% statistical power. Results: BMC had a significantly higher IL-1Ra concentration than all other preparations (all p < 0.0009, Figure 1). LR-PRP had a significantly higher IL-1Ra concentration than LP-PRP (p = 0.0006). There were no significant differences in IL-1Ra concentration based on age, gender, body mass index or chronicity of injury among all preparations (Table 1). BMC had significantly higher concentrations of leukocytes and monocytes compared to the other biologic preparations including LR-PRP. LP-PRP had significantly higher concentrations of matrix metalloproteinase (MMP)-2, MMP-3 and MMP-12 than all other preparations (all p < 0.007), while BMC had a significantly lower concentration of MMP-2 than all other preparations. LR-PRP had significantly higher concentrations of MMP-1, serum soluble CD40 ligand (sCD40 L), platelet derived growth factor (PDGF)-AA and PDGF-AB/BB than all other preparations (all p < 0.004). Conclusion: BMC is a clinically relevant source of anti-inflammatory biologic therapy that may be more effective in treating osteoarthritis and for use as an intra-articular biologic for augmented healing in the post-surgical inflammatory and healing phases due to its significantly higher concentration of IL-1Ra compared to LR-PRP and LP-PRP. Additionally, LR-PRP had a significantly higher concentration of IL-1Ra than LP-PRP. In cases where increased vascularity and healing are desired for pathological or injured tissues including muscle and tendon, LR-PRP may be optimal due to its higher overall concentrations of PDGF, TGF-β, EGF, VEGF, and sCD40 L. [Figure: see text][Table: see text]

Effect of Oral Losartan on Orthobiologics: Implications for Platelet-Rich Plasma and Bone Marrow Concentrate—A Rabbit Study

“…LP-PRP was tested since lower concentrations of leukocytes is less likely to induce excessive inflammation and fibrosis after an LP-PRP intra-articular injection [ 21 , 46 , 47 , 48 ].…”

“…Mix-species TGF-β magnetic bead panel (EMD Millipore Corp, Billerca, MA, USA) used were to measure TGF-β1 concentrations. A standard manufacturer’s protocol for the Luminex ® 200 system (Luminex Corp, Austin, TX, USA) multiplex instrument was utilized as previously published [ 47 ]. All reagents were prepared and stored according to manufacturer’s instructions.…”

Editorial Commentary: Platelet-Rich Plasma: The Devil Is in the Details, and the Details Need to Be Better Reported

“…The use of a more patient-specific PRP, with specific cytokines or growth factors knocked out for treating different knee conditions, may better direct the biological healing potential of PRP for different pathologies such as meniscal healing, articular cartilage resurfacing, and patellar tendinopathy. 8 Although the present study could certainly be demonstrated by others to be valid in future studies, there are some points that need to be addressed in biologics research to ensure that we are providing the best care for our patients. Among other essential criteria described by the minimum information for studies evaluating biologics in orthopedics guidelines, the methods of PRP preparation and the product components (platelets, leukocytes, and red cells) with their respective concentrations were not reported in the present study by Berdis et al Thus, others cannot duplicate this study as it is presented.…”

Platelet-rich plasma (PRP) as therapy for cartilage, tendon and muscle damage – German working group position statement

“…Also, a clinical study directly comparing LR- and LP-PRP shown no clinical difference in outcome after 12 months [ 23 ]. LR-PRP contains more proinflammatory molecules and a higher concentration of growth factors but also a higher concentration of anti-inflammatory cytokines like interleukin 1 receptor antagonist (IL1-Ra) [ 64 ]. Newer studies describe the process of “inflammatory regeneration” with the secretion of both pro- and anti-inflammatory cytokines by the leukocytes, showing positive effects on tissue regeneration [ 42 ].…”