The use of autologous platelet-rich plasma in the orthopedic setting

The Biological Use of Platelet-Rich Plasma in Skeletal Muscle Injury and Repair

Platelet-rich plasma (PRP) is a blood product that contains several growth factors and active proteins. PRP is thought to be used autologously to assist in the repair of injured tissues as well as to treat pain at the site of injury. The mechanism behind PRP in regenerative medicine has been well investigated and includes the identification and concentration of released growth factors and exosomes. The benefits of PRP have been highly recommended and are used widely in orthopaedics and sports medicine, including repair of injured skeletal muscle. This current report summarizes some of the more recent studies in the use of PRP as it relates to muscle healing, in both the in vitro and clinical arenas.

Apheresis practice patterns in the United States of America: Analysis of a market claims database

INTRODUCTION

Indications for apheresis procedures are expanding; however, the evidence for many is low quality. A better understanding of apheresis patterns in the United States is needed to better plan prospective research studies.

METHODS

Data from January 1, 2013, to September 30, 2015, were analyzed from the IBM MarketScan Research Databases of de-identified health insurance claims data of several million enrollees at all levels of care from large employers and health plans across the United States. Apheresis procedures were identified by International Classification of Diseases, Ninth version (ICD-9) and Current Procedure Terminology (CPT) codes.

RESULTS

Combining inpatients and outpatients, 18 706 patients underwent 70 247 procedures. The patients were 52.7% female, 5.1% <18 years, and 55.9% inpatient, while the procedures were 49.5% female, 5.7% <18 years, and 19.8% inpatient. For each apheresis modality, the percent of patients treated and procedures performed, respectively, are plasmapheresis 36.4% and 42.5%, autologous harvest of stem cells 22.8% and 10.7%, plateletpheresis 11.1% and 3.5%, allogeneic harvest of stem cells 8.2% and 2.5%, photopheresis 5.4% and 24.4%, erythrocytapheresis 3.8% and 4.7%, leukopheresis 2.0% and 0.7%, immunoadsorption 1.4% and 0.4%, extracorporeal selective adsorption/filtration and plasma reinfusion 1.0% and 3.6%, and other 21.6% and 6.9%. A wide variety of diagnoses were treated; however, analysis of the diagnoses suggests the procedure codes may not always reflect an apheresis procedure.

CONCLUSION

This study describes the landscape of apheresis in the United States, but may overestimate some procedures based on linked diagnosis codes. Direct measures of apheresis procedures are needed to plan future research studies.

Platelet-rich plasma: a narrative review

The aim of this article was to synopsize platelet-rich plasma (PRP) use in musculoskeletal pathologies through evidence-based assessment of the preparation, classification, mechanism of action and applications of PRP, thereby answering which PRP type is best for each clinical indication.

The literature search was performed using Medline, EMBASE and Cochrane Reviews databases for papers containing the key terms “platelet-rich plasma” AND “orthopaedics” AND (“classification” OR “mechanism of action” OR “preparation” OR “clinical application”). Generated papers were evaluated for pertinence in following areas: preparation, classification, mechanism of action, clinical application within orthopaedics. Non-English papers were excluded. Included studies were evaluated for quality.

Sixty studies were included in our review. There are many commercial PRP preparation kits with differing component concentrations. There is no consensus on optimal component concentrations. Multiple PRP classifications exist but none have been validated. Platelet-rich plasma acts via growth factors (GFs) released from α-granules within platelets. Growth factors have been shown to be beneficial in healing. Grossly elevated concentrations of GFs may have inhibitory effects on healing. Multiple systematic reviews show efficacy of PRP in tendinopathies, early osteoarthritis, acute muscle injuries and in combination with rotator cuff repair and anterior cruciate ligament reconstruction.

The literature suggests leukocyte-rich PRP (L-PRP) is more beneficial in tendinopathies and pure PRP (P-PRP) is more beneficial in cartilage pathology. However, different PRP preparations have not been directly compared in any pathology. Classification of PRP type is frequently not stated in research. Standardization of PRP research parameters is needed to streamline findings and generate clear indications for PRP types to yield maximum clinical benefit.

Cite this article: EFORT Open Rev 2021;6:225-235. DOI: 10.1302/2058-5241.6.200017

Spatial immobilization of endogenous growth factors to control vascularization in bone tissue engineering

An engineered biofunctional system comprises endogenous BMP-2 and VEGF bound in a parallel pattern. It successfully enabled obtaining the spatial osteogenic and angiogenic differentiation of human hBM-MSCs under basal culture conditions.

Efficacy of platelet-rich plasma as conservative treatment in orthopaedics: a systematic review and meta-analysis

BACKGROUND

The aim of this systematic review and meta-analysis was to evaluate the benefit of platelet-rich plasma (PRP) in non-surgical orthopaedic procedures.

MATERIAL AND METHODS

We searched the Cochrane Wounds Specialized Register, CENTRAL, MEDLINE (through PUBMED), Embase, and SCOPUS. We also searched clinical trials registries for ongoing and unpublished studies and checked reference lists to identify additional studies.

RESULTS

We found 36 randomised controlled trials (2,073 patients) that met our inclusion criteria. The included studies mostly had small numbers of participants (from 20 to 225). Twenty-eight studies included patients with lateral epicondylitis or plantar fasciitis. PRP was compared to local steroids injection (19 studies), saline injection (6 studies), autologous whole blood (4 studies), local anaesthetic injection (3 studies), dry needling injection (3 studies), and to other comparators (4 studies). Primary outcomes were pain and function scores, and adverse events. On average, it is unclear whether or not use of PRP compared to controls reduces pain scores and functional score at short- (up to 3 months) and medium- (4-6 months) term follow-up. The available evidence for all the comparisons was rated as very low quality due to inconsistency, imprecision, and risk of bias in most of the selected studies. There were no serious adverse events related to PRP injection or control treatments.

CONCLUSIONS

The results of this meta-analysis, which documents the very marginal effectiveness of PRP compared to controls, does not support the use of PRP as conservative treatment in orthopaedics.

Editorial Commentary: The Time Has Come to Try Intra-articular Platelet-Rich Plasma Injections for Your Patients With Symptomatic Knee Osteoarthritis

Platelet-rich plasma injections, in a systematic review and meta-analysis of 10 Level I randomized control trials, were found to provide more pain relief and better functional outcomes than hyaluronic acid in patients with knee osteoarthritis at 12 months after injection. The time has come for those of us who have not yet tried platelet-rich plasma injections in our patients with symptomatic knee osteoarthritis to do so.

Short term storage stability at room temperature of two different platelet-rich plasma preparations from equine donors and potential impact on growth factor concentrations

Background

The increasing interest in platelet-rich plasma (PRP) based therapies is as yet accompanied by inconsistent information regarding nearly all aspects of handling and application. Among these storage stability of processed platelet-rich products may be the basis for a more flexible application mode. The objective of this study was (1) to estimate the storage stability of growth factors platelet derived growth factor BB (PDGF-BB) and transforming growth factor ß1 (TGF-ß1) in both, a single-step softspin centrifugation-based pure-PRP (P-PRP, ACP®), and a gravity filtration system-based leukocyte-rich-PRP (L-PRP, E-PET), over a six hours time span after preparation at room temperature and (2) to identify possible factors influencing these growth factor concentrations in an equine model.

Results

Growth factor concentrations remained stable over the entire investigation period in L-PRP as well as P-PRP preparations revealing a mean of 3569 pg/ml PDGF-BB for E-PET and means of 1276 pg/ml PDGF-BB and 5086 pg/ml TGF-ß1 for ACP®. Pearson correlations yielded no significant impact of whole blood platelet (PLT), white blood cell (WBC) and red blood cell (RBC) counts on resulting cytokine values. In case of ACP® no significant dependencies between PLT, WBC and RBC counts of the processed platelet-rich product and resulting cytokine content occurred with exception of TGF-ß1 concentrations showing a strong correlation with the WBC content. PDGF-BB content of E-PET preparations showed a strong positive correlation with PLT and a strong negative with WBC of these preparations but not with RBC.

Conclusions

L-PRP ad modum E-PET and P-PRP ad modum ACP® are applicable over at least a six hours time span at room temperature without loss of growth factor content. Based on the results of this study factors influencing the resulting growth factor concentrations still remain questionable. Additional studies implicating a further standardization of preparation protocols are necessary to identify consistent impact on cytokine content after PRP processing.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-016-0920-4) contains supplementary material, which is available to authorized users.

Could Microparticles Be the Universal Quality Indicator for Platelet Viability and Function?

High quality means good fitness for the intended use. Research activity regarding quality measures for platelet transfusions has focused on platelet storage and platelet storage lesion. Thus, platelet quality is judged from the manufacturer's point of view and regulated to ensure consistency and stability of the manufacturing process. Assuming that fresh product is always superior to aged product, maintaining in vitro characteristics should preserve high quality. However, despite the highest in vitro quality standards, platelets often fail in vivo. This suggests we may need different quality measures to predict platelet performance after transfusion. Adding to this complexity, platelets are used clinically for very different purposes: platelets need to circulate when given as prophylaxis to cancer patients and to stop bleeding when given to surgery or trauma patients. In addition, the emerging application of platelet-rich plasma injections exploits the immunological functions of platelets. Requirements for quality of platelets intended to prevent bleeding, stop bleeding, or promote wound healing are potentially very different. Can a single measurable characteristic describe platelet quality for all uses? Here we present microparticle measurement in platelet samples, and its potential to become the universal quality characteristic for platelet production, storage, viability, function, and compatibility.

Platelet-Rich Plasma in a Murine Model: Leukocytes, Growth Factors, Flt-1, and Muscle Healing

BACKGROUND

It is well known that platelet-rich plasma (PRP) preparations are not the same and that not all preparations include white blood cells, but the part that leukocytes play on the healing role of PRP is still unknown.

PURPOSE

The primary aim of this study was to evaluate the influence of leukocytes in different PRP preparations with a special emphasis on growth factor concentrations. The secondary aim was to evaluate the influence of PRP on muscle healing.

STUDY DESIGN

Controlled laboratory study.

METHODS

Two PRP preparation procedures were evaluated. Blood fractions were stained with Rapid Panoptic, and growth factors (transforming growth factor beta 1 [TGF-β1], vascular endothelial growth factor [VEGF], insulin-like growth factor [IGF], epidermal growth factor [EGF], hepatocyte growth factor [HGF], and platelet-derived growth factor [PDGF]) were quantified by enzyme-linked immunosorbent assay. Western blotting analysis was performed for Fms-related tyrosine kinase 1 (Flt-1). A muscle contusion injury was created and treated with PRP at different time points.

RESULTS

Leukocytes were the main source of VEGF, and all other growth factors measured had a higher concentration in the preparations that included the buffy coat and consequently had a higher concentration of white blood cells. Flt-1 was also found in platelet-poor plasma (PPP). There were higher concentrations of PDGF and HGF in the preparations that encompassed the buffy coat. A PRP injection 7 days after the injury provided significantly increased exercise performance and decreased the fibrotic area when compared with other PRP-treated groups.

CONCLUSION

VEGF is only present in PRP's buffy coat, while Flt-1 is present in PPP. A PRP injection 7 days after an injury resulted in improved exercise performance.

CLINICAL RELEVANCE

The presence of Flt-1 in PRP provides yet another explanation for results described in the literature after a PRP injection. This information is relevant for selecting the best PRP for each type of injury.

Two complementary strategies to improve cell engraftment in mesenchymal stem cell-based therapy: Increasing transplanted cell resistance and increasing tissue receptivity

Over the past 2 decades, therapies based on mesenchymal stem cells (MSC) have been tested to treat several types of diseases in clinical studies, due to their potential for tissue repair and regeneration. Currently, MSC-based therapy is considered a biologically safe procedure, with the therapeutic results being very promising. However, the benefits of these therapies are not stable in the long term, and the final outcomes manifest with high inter-patient variability. The major cause of these therapeutic limitations results from the poor engraftment of the transplanted cells. Researchers have developed separate strategies to improve MSC engraftment. One strategy aims at increasing the survival of the transplanted MSCs in the recipient tissue, rendering them more resistant to the hostile microenvironment (cell-preconditioning). Another strategy aims at making the damaged tissue more receptive to the transplanted cells, favoring their interactions (tissue-preconditioning). In this review, we summarize several approaches using these strategies, providing an integral and updated view of the recent developments in MSC-based therapies. In addition, we propose that the combined use of these different conditioning strategies could accelerate the process to translate experimental evidences from pre-clinic studies to the daily clinical practice.