Plasma rich in growth factors (PRGF-Endoret) stimulates tendon and synovial fibroblasts migration and improves the biological properties of hyaluronic acid

Effectiveness of platelet derivatives in neuropathic pain management: A systematic review

BACKGROUND

Neuropathic pain (NP) has a considerable impact on the global economic burden and seriously impairs patients' quality of life. Currently there is no evidence-based "effective" treatment and new treatments are needed. Recently, platelet rich plasma (PRP) has emerged as an alternative treatment. Therefore, a systematic review has been conducted to present an evidence-based assessment of the use of PRP in the treatment of NP.

METHODS

Randomized studies that investigated the effect of PRP injection on patients with NP compared to alternative treatments or placebo were included. An encompassing search of specific databases, from their inception to April 2024, was performed. The databases were as follows: PubMed, Web of Sciences (MEDLINE) and Cochrane Library. The Cochrane Risk-of-Bias 2 tool was used to assess study methodological quality.

RESULTS

A total of 12 randomized studies with 754 patients with different NP conditions were included in this systematic review. According to the results from the qualitative analysis, PRP injection exerted a positive effect on improving pain intensity on most of the trials (8 out of 12). In the remaining studies, no differences were found. A high safety profile was reported with no serious adverse effects in the analysed patients.

CONCLUSION

PRP treatment might be an effective therapeutic approach for patients with different neuropathic pain conditions. The efficacy of PRP was not dependant on the aetiology of the underlying disorder; nevertheless, interpretations of the results should be performed cautiously, as for the under-representation of NP conditions.

Hyaluronic acid/platelet rich plasma-infused core-shell nanofiber membrane to prevent postoperative tendon adhesion and promote tendon healing

An anti-adhesive barrier membrane incorporating hyaluronic acid (HA) can reduce fibroblasts attachment and impart lubrication effect for smooth tendon gliding during management of post-surgical tendon adhesion. On the other hand, as numerous growth factors are required during tendon recovery, growth factors released by platelets in platelet-rich plasma (PRP) can provide beneficial therapeutic effects to facilitate tendon recovery post tendon injury. Furthermore, PRP is reported to be associated with anti-inflammatory properties for suppressing postoperative adhesion. Toward this end, we fabricate core-shell nanofiber membranes (NFM) with HA/PRP-infused core and polycaprolactone shell in this study. Different NFM with 100 % (H-P), 75 % (HP31-P), 50 % (HP11-P) and 25 % (H31-P) HA in the core was fabricated through coaxial electrospinning and analyzed through microscopic, pore size, mechanical, as well as HA and growth factor release studies. In vitro study with fibroblasts indicates the NFM can act as a barrier to prevent cell penetration and reduce cell attachment/focal adhesion, in addition to promoting tenocyte migration in tendon healing. In vivo studies in a rabbit flexor tendon rupture model indicates the HP11-P NFM shows improved efficacy over H-P NFM and control in reducing tendon adhesion formation and inflammation, while promoting tendon healing, from functional assays and histological analysis.

Effectiveness of Hyaluronic Acid Gel Injection with and without PRGF for Management of Interdental Papillary Loss: A Randomized Clinical Trial

BACKGROUND

To evaluate the effectiveness of hyaluronic acid (HA) gel injection with and without plasma rich in growth factors (PRGF) for the management of interdental papillary loss.

METHODS

A single blinded randomized clinical trial was carried out on 21 subjects with 34 sites. Patients within the age group 18-45 years who had Class I and II papillary recession in the maxillary anterior region were selected. The sites involved were randomly assigned to Group HA alone and Group HA + PRGF. The patients were recalled 4 weeks after receiving supragingival and subgingival instrumentation. HA or HA + PRGF was injected into the defective papilla at baseline and at 3 and 6 weeks. Image based measurements of Papillary Width (PW), Papillary Deficient Height (PDH), Deficient Area (DA), Deficient Volume (DV) were registered at baseline, 3 weeks, 6 weeks and 12 weeks. A vernier caliper was used to measure the papillary depth in the impression made using additional silicone impression material pre- and post-intervention.

RESULTS

There was a significant improvement in the within-group comparison of PW, PDH, DA and DV in both the groups. Group HA + PRGF showed significantly greater improvement in comparison to Group HA alone in terms of PDH, DA and DV at 6 and 12 weeks.

CONCLUSIONS

Even though HA gel has already been established as a promising injectable agent in the minimally invasive treatment of interdental papillary deficiency, PRGF may also have a significant adjuvant effect when used along with HA. Further clinical studies with longer follow up duration, larger sample size and standardization of the tooth shape are required for a better understanding of the adjuvant effect of PRGF when used along with HA.

Evaluation of Platelet-Rich Plasma by means of PRGF®-Endoret® protocol in leukemia cats: PDGF-BB and TGF-ß1 valuation

Introduction

Feline leukemia virus (FeLV) is a chronic disease that leads to the weakening of a cat's immune system. Platelet-rich plasma (PRP) offers therapeutic effects for multiple diseases, the use of PRP and growth factors (GFs) determination could be an alternative treatment to improve the quality of life in these patients. The objectives of this study were to determine and compare the concentration of platelets (PLTs), red blood cells (RBCs) and white blood cells (WBCs) between samples of whole blood (WB), PRP and platelet-poor plasma (PPP) fractions, and to evaluate the concentration of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor β1 (TGF-β1) in both fractions in FeLV cats using a PRGF^®-Endoret^® protocol previously standardized in this species.

Methods

WB was collected from 11 asymptomatic FeLV-positive cats. PRP and PPP was obtained following PRGF^®-Endoret^® technology according to centrifugation at 265 g for 10 min. Cellular components, RBCs, WBCs, PLTs, and the PDGF-BB and TGF-β1 concentrations in PRP and PPP fractions were determined.

Results

PLT in the PRP fraction was statistically higher than WB and PPP fraction, with no statistical differences between WB and PPP. PLT concentration increased 1.4 times in PRP fraction compared to WB. Mean platelet volume (MPV) did not differ significantly between the WB, PRP, and PPP fractions. Compared to WB, the absolute numbers of RBCs and WBCs were decreased by 99% and more than 95% in the PRP and PPP fractions, respectively. TGF-ß1 concentrations increased in PRP vs. PPP, with no changes in PDGF-BB.

Discussion

Based on the degree of PLT enrichment and the absence of RBCs and WBCs, this blood product could be classified as a Pure Platelet-Rich Plasma (P-PRP). The presence of GFs in PRP and PPP samples suggests that the PRGF^®-Endoret^® methodology is suitable for obtaining PRP in FeLV cats, despite future studies are necessary to optimize the technique, standardize the results and assess clinical efficacy.

Interventional Therapies for Osteoarthritis: An Update

Osteoarthritis (OA) is one of the most common diseases worldwide and is expected to increase in incidence as the age of the general population rises. Both oral medications, such as NSAIDs, and surgical treatments used for OA management have limitations. Demand is rising for minimally invasive techniques such as intraarticular injections and percutaneous interventions for use in place of or in conjunction with oral medications and surgical therapies, and the past 2 decades have seen a rapid expanse in both pharmacologic and nonpharmacologic minimally invasive OA treatments. Image guidance with fluoroscopy, CT, or ultrasound is often used in conjunction with these procedures to achieve precise treatment localization to achieve maximal therapeutic effect. The choice of modality used for image guidance is often influenced by clinician experience, patient characteristics, and equipment availability. This article reviews the mechanisms of action, contraindications, complications, and efficacy of conventional and developing minimally invasive OA treatments. The minimally invasive treatment options described in this Review include therapeutic injections such as antiinflammatory agents, viscosupplements, and biologics, as well as nonpharmacologic treatments of subchondroplasty, nerve ablation, genicular artery embolization, intraarticular pulsed radiofrequency therapy, and MRI-guided focused ultrasound therapy.

Comparing efficacy of a single intraarticular injection of platelet-rich plasma (PRP) combined with different hyaluronans for knee osteoarthritis: a randomized-controlled clinical trial

BACKGROUND

Intraarticular plasma-rich platelet (PRP) and hyaluronic acid (HA) have each been shown to be effective for treating knee osteoarthritis (OA). Evidence supporting the combination therapy is controversial. This study aimed to investigate the efficacy of a single intraarticular PRP injection combined with different HAs in patients with knee OA.

METHODS

In this prospective randomized-controlled trial, 99 patients with Kellgren-Lawrence grade 2 knee OA with average knee pain ≥ 30 mm on a 0-100 mm pain visual analog scale (VAS) were randomized into two groups. The PRP + Artz group received a single intraarticular HA (Artz, 2.5 ml, 10 mg/ml) followed by 3 ml PRP (n = 50). The PRP + HYAJOINT Plus group received a single intraarticular cross-linked HA (HYAJOINT Plus, 3 ml, 20 mg/ml) followed by 3 ml PRP (n = 49). All patients were evaluated before and at 1, 3 and 6 months after injections. The primary outcome was the VAS pain reduction from baseline at 6 months. Secondary outcome measures included Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lequesne index, single leg stance (SLS) test and patient satisfaction.

RESULTS

Ninety-five patients were analyzed by intention-to-treat analysis. Both groups improved significantly in VAS pain, WOMAC, Lequesne index and SLS at 1, 3 and 6 months post intervention (p < 0.05). Between-group comparisons showed no significant differences at most follow-up time points, except better improvements in Lequesne index at 1 month (p = 0.003) and WOMAC-stiffness score at 6 months (p = 0.020) in the PRP + Artz group, and superiority in SLS at 1, 3 and 6 months in the PRP+ HYAJOINT Plus group (p < 0.001, p = 0.003 and p = 0.004). Additional Johnson-Neyman analyses showed that among the patients with baseline WOMAC-pain score > 8.5, WOMAC-function score > 21.7 and WOMAC-total score > 32.0, respectively, those treated with PRP + HYAJOINT Plus injections had better effects in WOMAC-pain, WOMAC-function and WOMAC-total scores than those treated with PRP + Artz at 3 months postinjection (p < 0.05). Both groups reported high satisfaction. No serious adverse events occurred during the study.

CONCLUSIONS

A single PRP injection combined with Artz or HYAJOINT Plus is effective and safe for 6 months in patients with knee OA. Both injection regimens are potential treatment options for knee OA. Further studies are needed to confirm these results.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov (NCT04931719), retrospectively. Date of registration 18/6/2021.

NAME OF TRIAL REGISTRY

Comparing efficacy of single PRP combined with different hyaluronans for knee osteoarthritis.

LEVEL OF EVIDENCE

Therapeutic Level 1.

A Promising Candidate in Tendon Healing Events—PDGF-BB

Tendon injuries are one of the most common musculoskeletal disorders for which patients seek medical aid, reducing not only the quality of life of the patient but also imposing a significant economic burden on society. The administration of growth factors at the wound site is a feasible solution for enhancing tendon healing. Platelet-derived growth factor-BB (PDGF-BB) has a well-defined safety profile compared to other growth factors and has been approved by the Food and Drug Administration (FDA). The purpose of this review is to summarize the role of PDGF-BB in tendon healing through a comprehensive review of the published literature. Experimental studies suggest that PDGF-BB has a positive effect on tendon healing by enhancing inflammatory responses, speeding up angiogenesis, stimulating tendon cell proliferation, increasing collagen synthesis and increasing the biomechanics of the repaired tendon. PDGF-BB is regarded as a promising candidate in tendon healing. However, in order to realize its full potential, we still need to carefully consider and study key issues such as dose and application time in the future, so as to explore further applications of PDGF-BB in the tendon healing process.

Efficacy of a Novel Intra-Articular Administration of Platelet-Rich Plasma One-Week Prior to Hyaluronic Acid versus Platelet-Rich Plasma Alone in Knee Osteoarthritis: A Prospective, Randomized, Double-Blind, Controlled Trial

Recent studies have suggested that the combined injection of platelet-rich plasma (PRP) and hyaluronic acid (HA) may have additive benefits for knee osteoarthritis over PRP alone, but there is insufficient evidence to support this combined injection. Moreover, the simultaneous injection of PRP and HA may offset the combined effect. Hence, the aim of this prospective, randomized, double-blind study was to assess their combined efficacy with a novel injection protocol. Forty-six study subjects with unilateral knee osteoarthritis were randomized to receive either a single-dose injection of HA (intervention group) or normal saline (control group) 1 week after a single-dose injection of leukocyte-poor PRP. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and static balance and the risk of falls measured by Biodex Balance System were, respectively, the primary and secondary outcome measures. Evaluations were performed at baseline, 1 month, 3 months, 6 months, and 12 months post-injection. The intervention group exhibited significant declines in WOMAC pain, stiffness, and total scores, as well as static balance, compared to the control group (p < 0.05). These randomized double-blind control trials, with novel protocol of intra-articular injection of PRP 1-week prior to HA, provide greater symptom relief and improve static balance compared to PRP alone in patients with knee osteoarthritis.

Treating Knee Osteoarthritis With Platelet-Rich Plasma and Hyaluronic Acid Combination Therapy: A Systematic Review

BACKGROUND

Platelet-rich plasma (PRP) and hyaluronic acid (HA) are injectable treatments for knee osteoarthritis. The focus of previous studies has compared their efficacy against each other as monotherapy. However, a new trend of combining these 2 injections has emerged in an attempt to have a synergistic effect.

PURPOSE

To systematically review the clinical literature examining the combined use of PRP + HA.

DESIGN

Systematic review.

METHODS

A systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using PubMed and Embase. The following search terms were used: knee osteoarthritis AND platelet rich plasma AND hyaluronic acid. The review was performed by 2 independent reviewers who applied the inclusion/exclusion criteria and independently extracted data, including methodologic scoring, PRP preparation technique, HA composition, and patient-reported outcomes (PROs).

RESULTS

A total of 431 articles were screened, 12 reviewed in full, and 8 included in the final analysis: 2 case series, 3 comparative, and 3 randomized studies. Average follow-up was 9 months. The modified Coleman Methodology Score was 38.13 ± 13.1 (mean ± SD). Combination therapy resulted in improved PROs in all studies. Of the comparative and randomized studies, 2 demonstrated that combination therapy was superior to HA alone. However, when PRP alone was used as the control arm (4 studies), combination therapy was not superior to PRP alone.

CONCLUSION

Combination therapy with PRP + HA improves PROs and is superior to HA alone but is not superior to PRP alone.

Platelet-Rich Plasma in Facial Rejuvenation: A Systematic Appraisal of the Available Clinical Evidence

Purpose

Platelet-rich plasma (PRP) is a promising noninvasive technique for facial rejuvenation. This systematic literature review aims to appraise the nature and quality of published evidence evaluating the effectiveness and safety of PRP in facial rejuvenation.

Patients and Methods

A systematic literature review was conducted with the search string “Platelet-rich plasma AND Facial rejuvenation” in PubMed and Embase. Clinical studies evaluating the outcomes after PRP-based facial rejuvenation either as monotherapy or in combination with other treatment modalities were included. Studies evaluating wound-healing properties of PRP were excluded. The outcomes included both patient-reported and physician-assessed outcomes. Nonstatistical synthesis of evidence was performed by qualitative assessment. The results are reported by the Synthesis Without Meta-analysis (SWiM) reporting standard.

Results

A total of 36 studies that included a total of 3172 patients were considered for the evidence synthesis. The number of patients in the included studies ranging from 11 to 2005 with a median of 27.5 patients that reflects the challenges in clinically assessing the aesthetic outcomes after PRP-based facial rejuvenation. Among the 36 studies, 17 were observational studies and 18 were interventional studies with 1 being case report PRP was evaluated either alone or in combination with hyaluronic acid, lipofilling, micro-needling technique, and laser-based interventions. Among the studies, 1 study reported the enhanced platelet concentrate in a fibrin matrix to be relatively safe and effective with a maximum benefit observed at 12 weeks suggesting the platelet-rich fibrin matrix may provide desired aesthetic outcomes and it requires further studies to substantiate.

Conclusion

The results suggest very limited clinical evidence, and further clinical studies are warranted to establish the effectiveness of PRP in facial rejuvenation. Furthermore, a consensus for end points used for establishing clinical utility in patients requiring facial rejuvenation is warranted.

Healing through the lens of immunothrombosis: Biology-inspired, evolution-tailored, and human-engineered biomimetic therapies

Evolution, from invertebrates to mammals, has yielded and shaped immunoclotting as a defense and repair response against trauma and infection. This mosaic of immediate and local wound-sealing and pathogen-killing mechanisms results in survival, restoration of homeostasis, and tissue repair. In mammals, immunoclotting has been complemented with the neuroendocrine system, platelets, and contact system among other embellishments, adding layers of complexity through interconnecting blood-born proteolytic cascades, blood cells, and the neuroendocrine system. In doing so, immunothrombosis endows humans with survival advantages, but entails vulnerabilities in the current unprecedented and increasingly challenging environment. Immunothrombosis and tissue repair appear to go hand in hand with common mechanisms mediating both processes, a fact that is underlined by recent advances that are deciphering the mechanisms of the repair process and of the biochemical pathways that underpins coagulation, hemostasis and thrombosis. This review is intended to frame both the universal aspects of tissue repair and the therapeutic use of autologous fibrin matrix as a biology-as-a-drug approach in the context of the evolutionary changes in coagulation and hemostasis. In addition, we will try to shed some light on the molecular mechanisms underlying the use of the autologous fibrin matrix as a biology-inspired, evolution-tailored, and human-engineered biomimetic therapy.

Plasma Rich in Growth Factors Promotes Autophagy in ARPE19 Cells in Response to Oxidative Stress Induced by Blue Light

Age-related macular degeneration (AMD) causes the degeneration of photoreceptors and retinal cells leading to vision loss in older subjects. Among possible exogenous risk factors, it has been recently proposed that long-term exposure to blue light could aggravate the course of AMD. In the search for therapeutic options, plasma rich in growth factors (PRGF) has been shown to enhance cell antioxidant pathways and protect photoreceptors against the harm produced by blue light, although its mechanism of action remains unknown. One possible mechanism, autophagy, is one of the most conservative cell renewal systems used in eukaryotes to destroy cellular components that have been damaged by some kind of insult. The oxidative stress of exposure to blue light is known to induce cell autophagy. In this study, we examined the combined effects on autophagy of blue light and PRGF in a retinal cell line, ARPE19. In response to treatment with both PRGF and blue light, we detected the modulated expression of autophagy markers such as NF-kB, p62/sqstm1, Atg5, LC3 and Beclin1, and inflammatory markers such as IL1B and IL18. Our findings suggest that PRGF promotes cell autophagy in response to exposure to blue light.

Platelet-rich therapies as an emerging platform for regenerative medicine

INTRODUCTION

The combination of human plasma components with the multiple secretome from platelets has provided a new biological tool that is shaping a new future for its direct application in tissue regeneration as well as in cell culture and advanced therapy by means of its use as a clinical-grade supplement.

AREAS COVERED

Some relevant aspects related to the biology, growth factor delivery and molecular pathways driving the biological effects of platelet-rich therapies are summarized. Their use as clinical-grade cell supplements and advanced therapies is also carefully described.

EXPERT OPINION

Platelet-rich plasma therapies, and especially PRGF, contain an incredible number of biologically active agents that may exert regenerative and therapeutic potential. Here, we highlight the latest advances in this biological approach for the delivery of autologous growth factors with some of the recent new applications including the development of a clinical-grade supplement for advanced therapy.

Differentiation of human adipose-derived mesenchymal stem cells toward tenocyte by platelet-derived growth factor-BB and growth differentiation factor-6

Mesenchymal Stem Cells (MSCs) are important in regenerative medicine and tissue engineering and will be a very sensible choice for repair and regeneration of tendon. New biological practices, such as cellular therapy using stem cells, are promising for facilitating or expediting tendon therapy. Before using these cells clinically, it is best to check and confirm the optimal conditions for differentiation of these cells in the laboratory. Hence, in the present study, the impacts of PDGF-BB and GDF-6 supplementation on adipose-derived MSCs (ASCs) culture were studied. The frozen ASC were recovered and expanded in basic culture medium (DMEM with 10%FBS). The cells after passage five (P5) were treated with basic medium containing L-Prolin, Ascorbic Acid and only PDGF-BB or GDF-6 (20 ng/ml) or both of them (mix) as 3 groups for 14 days to investigate efficiency of ASCs differentiation towards tenocytes. The cells culturing in basic medium were used as control group. To validate tenogenic differentiation, H&E and Sirius Red staining were used to assess cell morphology and collagen production, respectively. In addition, mRNA levels of collagen I and III, Scleraxis and Tenomodulin as tenogenic markers were analyzed using qPCR. In all test groups, cells appeared slenderer, elongated cytoplasmic attributes compared to the control cells. The intensity of Sirius Red staining was significantly higher in GDF-6, PDGF-BB alone, than in group without supplements. The optical density was higher in the GDF-6 than PDGF-BB and mix-group. QPCR results showed that Col I and III gene expression was increased in all groups compared to the control. SCX expression was significantly increased only in the PDGF-BB group. TNMD mRNA expression was not significant among groups. In this study, we have corroborated that human ASCs are reactionary to tenogenic induction by GDF-6 and PDGF-BB alone or in combination. These outcomes will help greater insight into GDF-6 and PDGF-BB driven tenogenesis of ASCs and new directions of discovery in the design of ASC-based treatments for tendon healing.

Platelet-Rich Plasma Combined With Hyaluronic Acid Improves Pain and Function Compared With Hyaluronic Acid Alone in Knee Osteoarthritis: A Systematic Review and Meta-analysis

PURPOSE

To evaluate the efficacy of platelet-rich plasma (PRP) combined with hyaluronic acid (HA) injections versus HA injections alone for the management of knee osteoarthritis (OA).

METHODS

This study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eligible randomized-controlled trials and observational studies directly comparing combined PRP-HA injections with HA injections alone were identified through a search of PubMed, Scopus, and Cochrane Central databases from inception to May 2020. A random effects model meta-analysis was conducted and the I² statistic was used to assess for heterogeneity.

RESULTS

Four studies comprising 377 patients (PRP-HA: 193, HA: 184) with knee OA ranging from I-IV Kellgren-Lawrence grading scale were included. The final follow-up was 12 months in 3 studies and 6 months in 1 study. Patients who received PRP combined with HA had significantly greater improvements compared with those injected with HA alone in terms of visual analog scale scores at 3-month (standardized mean difference [SMD] 1.13; 95% confidence interval [CI] 0.56-1.70; I² = 56.7%; P < .001), 6-month (SMD 1.08; 95% CI 0.54-1.62; I² = 67.9%; P < .001), and 12-month (SMD 1.13; 95% CI 0.74-1.52; I² = 0.0%; P < .001) and 12-month Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical functioning (SMD 0.91; 95% CI 0.65-1.17; I² = 0.0%; P < .001) and 12-month WOMAC stiffness (SMD 1.09; 95% CI 0.80-1.38; I² = 0.0%; P < .001) scores. No difference was identified in terms of 12-month WOMAC pain score (SMD 0.36; 95% CI -0.19 to 0.91; I² = 74.1%; P = .195).

CONCLUSIONS

Symptomatic patients with knee OA who were injected with a combination of PRP and HA demonstrated greater improvement in pain and function compared with patients who received HA injections only, as assessed by 3-, 6-, and 12-month visual analog scale scores and 12-month WOMAC physical function and stiffness scores. This study provides encouraging evidence for the use of the combined PRP-HA injections in the management of symptomatic patients with knee OA.

LEVEL OF EVIDENCE

III (meta-analysis of randomized and non-randomized comparative trials).

Comparing efficacy of intraarticular single crosslinked Hyaluronan (HYAJOINT Plus) and platelet-rich plasma (PRP) versus PRP alone for treating knee osteoarthritis

Intraarticular hyaluronan or platelet-rich plasma (PRP) is widely used in the treatment of knee osteoarthritis (OA). The efficacy of combined hyaluronan with PRP remained inconclusive. This study aimed to investigate the efficacy of combined a single crosslinked hyaluronan (HYAJOINT Plus) and a single PRP versus a single PRP in patients with knee OA. In a prospective randomized-controlled trial, 85 patients with knee OA (Kellgren-Lawrence 2) were randomized to receive a single intraarticular injection of HYAJOINT Plus (3 ml, 20 mg/ml) followed by 3 ml PRP (the combined-injection group, N = 43) or a single injection of 3 ml PRP (the one-injection group, N = 42). The primary outcome was the change from baseline in the visual analog scale (VAS) pain (0–00 mm) at 6 months. Secondary outcomes included The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC, Likert Scale), Lequesne index, single leg stance test (SLS), use of rescue analgesics and patient satisfaction at 1, 3 and 6 months. Seventy-eight patients were available for the intention-to-treat analysis at 6 months. Both groups improved significantly in VAS pain, WOMAC, Lequesne index and SLS at each follow-up visit (p < 0.001). Patients receiving a single PRP experienced significantly greater improvements in VAS pain than patients receiving combined injections at 1-month follow-up (adjusted mean difference: − 5.6; p = 0.017). There were no significant between-group differences in several of the second outcomes at each follow-up visit, except the WOMAC-pain and WOMAC-stiffness scores favoring the one-injection group at 1 month (p = 0.025 and p = 0.011). However, at 6-month follow-up, the combined-injection group achieved significantly better VAS pain reduction (p = 0.020). No serious adverse events occurred following injections. In conclusion, either combined injections of HYAJOINT Plus and PRP or a single PRP alone was safe and effective for 6 months in patients with Kellgren-Lawrence 2 knee OA. Combined injections of HYAJOINT Plus and PRP achieved better VAS pain reduction than a single PRP at 6 months. The results indicating a long term benefit effect of a combination of HYAJOINT Plus and PRP in a particular subset of patients with moderate knee OA need to be replicated in larger trials.

ClinicalTrials.gov number NCT04315103.

Plasma Rich in Growth Factors Enhances Cell Survival after in Situ Retinal Degeneration

PURPOSE

The purpose of this study was to examine the effect of plasma rich in growth factors (PRGFs) under blue light conditions in an in vivo model of retinal degeneration.

METHODS

Male Wistar rats were exposed to dark/blue light conditions for 9 days. On day 7, right eyes were injected with saline and left eyes with PRGF. Electroretinography (ERG) and intraocular pressure (IoP) measurements were performed before and after the experiment. After sacrifice, retinal samples were collected. Hematoxylin and eosin staining was performed to analyze the structure of retinal sections. Immunofluorescence for brain-specific homeobox/POU domain protein 3A (Brn3a), choline acetyltransferase (ChAT), rhodopsin, heme oxygenase-1 (HO-1), and glial fibrillary acidic protein (GFAP) was performed to study the retinal conditions.

RESULTS

Retinal signaling measured by ERG was reduced by blue light and recovered with PRGF; however, IoP measurements did not show significant differences among treatments. Blue light reduced the expression for Brn3a, ChAT, and rhodopsin. Treatment with PRGF showed a recovery in their expressions. HO-1 and GFAP results showed that blue light increased their expression but the use of PRGF reduced the effect of light.

CONCLUSIONS

Blue light causes retinal degeneration. PRGF mitigated the injury, restoring the functionality of these cells and maintaining the tissue integrity.

Effects and safety of the combination of platelet-rich plasma (PRP) and hyaluronic acid (HA) in the treatment of knee osteoarthritis: a systematic review and meta-analysis

Background

Studies have shown that the combined application of hyaluronic acid (HA) and platelet-rich plasma (PRP) can repair degenerated cartilage and delay the progression of knee osteoarthritis (KOA). The purpose of this study was to explore the efficacy and safety of the intra-articular injection of PRP combined with HA compared with the intra-articular injection of PRP or HA alone in the treatment of KOA.

Methods

The PubMed, Cochrane Library, EMBASE and China National Knowledge Infrastructure (CNKI) databases were searched from inception to December 2019. Randomized controlled trials and cohort studies of PRP combined with HA for KOA were included. Two orthopaedic surgeons conducted the literature retrieval and extracted the data. Outcome indicators included the Western Ontario and McMaster Universities Arthritis Index (WOMAC), the Lequesne Index, the visual analogue scale (VAS) for pain, and adverse events (AEs). Review Manager 5.3 was used to calculate the relative risk (RR) or standardized mean difference (SMD) of the pooled data. STATA 14.0 was used for quantitative publication bias evaluation.

Results

Seven studies (5 randomized controlled trials, 2 cohort studies) with a total of 941 patients were included. In the VAS comparison after 6 months of follow-up, PRP combined with HA was more likely to reduce knee pain than PRP alone (SMD: − 0.31; 95% confidence interval (CI): − 0.55 to − 0.06; P = 0.01 < 0.05). PRP combined with HA for KOA achieved better improvements in the WOMAC Function Score (SMD: -0.32; 95% CI: − 0.54 to − 0.10; P < 0.05) and WOMAC Total Score (SMD: -0.42; 95% CI: − 0.67 to − 0.17; P < 0.05) at the 12-month follow-up than did the application of PRP alone. In a comparison of Lequesne Index scores at the 6-month follow-up, PRP combined with HA improved knee pain scores more than PRP alone (SMD: -0.42; 95% CI: − 0.67 to − 0.17; P < 0.05). In terms of AEs, PRP combined with HA was not significantly different from PRP or HA alone (P > 0.05).

Conclusions

Compared with intra-articular injection of PRP alone, that of PRP combined with HA can improve the WOMAC Function Scores, WOMAC Total Score, 6-month follow-up VAS ratings, and Lequesne Index scores. However, in terms of the incidence of AEs, PRP combined with HA is not significantly different from PRP or HA alone.

Platelet Concentrates in Musculoskeletal Medicine

Platelet concentrates (PCs), mostly represented by platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) are autologous biological blood-derived products that may combine plasma/platelet-derived bioactive components, together with fibrin-forming protein able to create a natural three-dimensional scaffold. These types of products are safely used in clinical applications due to the autologous-derived source and the minimally invasive application procedure. In this narrative review, we focus on three main topics concerning the use of platelet concentrate for treating musculoskeletal conditions: (a) the different procedures to prepare PCs, (b) the composition of PCs that is related to the type of methodological procedure adopted and (c) the clinical application in musculoskeletal medicine, efficacy and main limits of the different studies.

Antioxidant Role of PRGF on RPE Cells after Blue Light Insult as a Therapy for Neurodegenerative Diseases

Oxidative stress has a strong impact on the development of retinal diseases such as age-related macular degeneration (AMD). Plasma rich in growth factors (PRGF) is a novel therapeutic approach in ophthalmological pathologies. The aim of this study was to analyze the antioxidant effect of PRGF in retinal epithelial cells (EPR) in in vitro and ex vivo retinal phototoxicity models. In vitro analyses were performed on ARPE19 human cell line. Viability and mitochondrial status were assessed in order to test the primary effects of PRGF. GSH level, and protein and gene expression of the main antioxidant pathway (Keap1, Nrf2, GCL, HO-1, and NQO1) were also studied. Ex vivo analyses were performed on rat RPE, and HO-1 and Nrf2 gene and protein expression were evaluated. The results show that PRGF reduces light insult by stimulating the cell response against oxidative damage and modulates the antioxidant pathway. We conclude that PRGF’s protective effect could prove useful as a new therapy for treating neurodegenerative disorders such as AMD.

Centrifugation Conditions in the L-PRP Preparation Affect Soluble Factors Release and Mesenchymal Stem Cell Proliferation in Fibrin Nanofibers

Leukocyte and platelet-rich plasma (L-PRP) is an autologous product that when activated forms fibrin nanofibers, which are useful in regenerative medicine. As an important part of the preparation of L-PRP, the centrifugation parameters may affect the release of soluble factors that modulate the behavior of the cells in the nanofibers. In this study, we evaluated the influences of four different centrifugation conditions on the concentration of platelets and leukocytes in L-PRP and on the anabolic/catabolic balance of the nanofiber microenvironment. Human adipose-derived mesenchymal stem cells (h-AdMSCs) were seeded in the nanofibers, and their viability and growth were evaluated. L-PRPs prepared at 100× g and 100 + 400× g released higher levels of transforming growth factor (TGF)-β1 and platelet-derived growth factor (PDGF)-BB due to the increased platelet concentration, while inflammatory cytokines interleukin (IL)-8 and tumor necrosis factor (TNF)-α were more significantly released from L-PRPs prepared via two centrifugation steps (100 + 400× g and 800 + 400× g) due to the increased concentration of leukocytes. Our results showed that with the exception of nanofibers formed from L-PRP prepared at 800 + 400× g, all other microenvironments were favorable for h-AdMSC proliferation. Here, we present a reproducible protocol for the standardization of L-PRP and fibrin nanofibers useful in clinical practices with known platelet/leukocyte ratios and in vitro evaluations that may predict in vivo results.

Hyaluronic Acid Combined with Serum Rich in Growth Factors in Corneal Epithelial Defects

The aim of this study is to assess if an adhesive biopolymer, sodium hyaluronate (NaHA), has synergistic effects with s-PRGF (a serum derived from plasma rich in growth factors and a blood derivative that has already shown efficacy in corneal epithelial wound healing), to reduce time of healing or posology. In vitro proliferation and migration studies, both in human corneal epithelial (HCE) cells and in rabbit primary corneal epithelial (RPCE) cultures, were carried out. In addition, we performed studies of corneal wound healing in vivo in rabbits treated with s-PRGF, NaHA, or the combination of both. We performed immunohistochemistry techniques (CK3, CK15, Ki67, ß4 integrin, ZO-1, α-SMA) in rabbit corneas 7 and 30 days after a surgically induced epithelial defect. In vitro results show that the combination of NaHA and s-PRGF offers the worst proliferation rates in both HCE and RPCE cells. Addition of NaHA to s-PRGF diminishes the re-epithelializing capability of s-PRGF. In vivo, all treatments, given twice a day, showed equivalent efficacy in corneal epithelial healing. We conclude that the combined use of s-PRGF and HaNA as an adhesive biopolymer does not improve the efficacy of s-PRGF alone in the wound healing of corneal epithelial defects.

Improvising PRP for use in osteoarthritis knee- upcoming trends and futuristic view

Platelet rich plasma (PRP) has clearly emerged offering a possible solution that could modify the disease process and offer symptomatic relief in early osteoarthritis of knee. Great efforts are underway to improve PRP products for use in knee osteoarthritis (OA). Upcoming research is focused on the ideal PRP type, dose, frequency of injection and mode of injection. The combination of PRP with biocompatible carriers/scaffolds like gelatin hydrogel and chitosan appear to be promising based on early in vitro and animal studies. PRP in combination with hyaluronate has also emerged to have synergistic and additive effects. This article intends to review the recent trends and advancing ideas for improvising PRP for use in early knee OA treatment.

Autologous fibrin scaffolds: When platelet- and plasma-derived biomolecules meet fibrin

The healing of vascularized mammalian tissue injuries initiate with hemostasis and clotting as part of biological defense system leading to the formation of a fibrin clot in which activated platelets are trapped to quickly stop bleeding and destroy microbials. In order to harness the therapeutic potential of biomolecules secreted by platelets and stemmed from plasma, blood deconstruction has allowed to yield autologous platelet-and plasma-derived protein fibrin scaffold. The autologous growth factors and microparticles stemmed from platelets and plasma, interact with fibrin, extracellular matrix, and tissue cells in a combinatorial, synergistic, and multidirectional way on mechanisms governing tissue repair. This interplay will induce a wide range of cell specifications during inflammation and repair process including but not limited to fibrogenesis, angiogenesis, and immunomodulation. As biology-as-a-drug approach, autologous platelet-and plasma-derived protein fibrin scaffold is emerging as a safe and efficacious natural human-engineered growth factor delivery system to repair musculoskeletal tissues, and skin and corneal ulcers and burns. In doing so, it acts as therapeutic agent not perfect but close to biological precision. However, this autologous, biocompatible, biodegradable, and long in vivo lasting strategy faces several challenges, including its non-conventional single dose-response effect, the lack of standardization in its preparation and application, and the patient's biological features. In this review, we give an account of the main events of tissue repair. Then, we describe the procedure to prepare autologous platelet-and plasma-derived protein fibrin scaffolds, and the rationale behind these biomaterials, and finally, we highlight the significance of strategic accuracy in their application.

Biological Treatment for Osteoarthritis of the Knee: Moving from Bench to Bedside-Current Practical Concepts

Biological-based therapies for cartilage pathology have gained considerable recognition in the last few decades due to their potential benefits including their minimal invasiveness, capacity for unprecedented healing, and potential for rapid recovery. Consequently, these therapies are likely to have the most noteworthy impact on patients with degenerative joint changes who want to remain active. Currently, the most researched treatments include platelet-rich plasma (PRP), bone marrow aspirate concentrate (BMAC), and cell-based therapies. Although further basic science research and well-designed randomized clinical trials are needed to elucidate the long-term role of these therapies in the treatment of osteoarthritis, there is compelling evidence for their use for certain indications. This article aims to review the existing literature for biological-based treatment options for osteoarthritis, critically assessing the current evidence-based recommendations and identify potential avenues for development.

Hyaluronic Acid

In recent times, the field of tissue engineering and regenerative medicine (TERM) has considerably increased the extent of therapeutic strategies for clinical application in orthopedics. However, TERM approaches have its rules and requirements, in the respect of the biologic response of each tissue and bioactive agents which need to be considered, respected, and subject of ongoing studies. Different medical devices/products have been prematurely available on the market and used in clinics with limited success. However, other therapeutics, when used in a serious and evidence-based approach, have achieved considerable success, considering the respect for solid expectations from doctors and patients (when properly informed).Orthobiologics has appeared as a recent technological trend in orthopedics. This includes the improvement or regeneration of different musculoskeletal tissues by means of using biomaterials (e.g., hyaluronic acid), stem cells, and growth factors (e.g., platelet-rich plasma). The potential symbiotic relationship between biologic therapies and surgery makes these strategies suitable to be used in one single intervention.However, herein, the recent clinical studies using hyaluronic acid (HA) in the treatment of orthopedic conditions will mainly be overviewed (e.g., osteochondral lesions, tendinopathies). The possibilities to combine different orthobiologic agents as TERM clinical strategies for treatment of orthopedic problems will also be briefly discussed.

Current concepts in treatment of early knee osteoarthritis and osteochondral lesions; the role of biological augmentations

Early knee osteoarthritis and chondral lesions are a common cause of disability in younger patients. Surgical options, such as microfractures, ACI and OAT, provide good, but not fully satisfying, outcomes. Recent advance in biological knowledge introduced two different methodological approaches of delivering growth factors and stem cells into the articular environment. Platelet-Rich Plasma and Mesenchimal Stem Cells are supposed to change the way to approach early knee osteoarthritis and chondral lesions, though their indications and limits are yet to be determined.

Current concepts in treatment of early knee osteoarthritis and osteochondral lesions; the role of biological augmentations

Early knee osteoarthritis and chondral lesions are a common cause of disability in younger patients. Surgical options, such as microfractures, ACI and OAT, provide good, but not fully satisfying, outcomes. Recent advance in biological knowledge introduced two different methodological approaches of delivering growth factors and stem cells into the articular environment. Platelet-Rich Plasma and Mesenchimal Stem Cells are supposed to change the way to approach early knee osteoarthritis and chondral lesions, though their indications and limits are yet to be determined.

In situ assembly of fibrinogen/hyaluronic acid hydrogel via knob-hole interaction for 3D cellular engineering

Hyaluronic acid (HA)-based hydrogels have applied widely for biomedical applications due to its biocompatibility and biodegradability. However, the use of initiators or crosslinkers during the hydrogel formation may cause cytotoxicity and thereby impair the biocompatibility. Inspired by the crosslinking mechanism of fibrin gel, a novel HA-based hydrogel was developed via the in situ supramolecular assembly based on knob-hole interactions between fibrinogen and knob-grafted HA (knob-g-HA) in this study. The knob-grafted HA was synthesized by coupling knob peptides (GPRPAAC, a mimic peptide of fibrin knob A) to HA via Michael addition. Then the translucent fibrinogen/knob-g-HA hydrogels were prepared by simply mixing the solutions of knob-g-HA and fibrinogen at the knob/hole ratio of 1.2. The rheological behaviors of the fibrinogen/knob-g-HA hydrogels with the fibrinogen concentrations of 50, 100 and 200 mg/mL were evaluated, and it was found that the dynamic storage moduli (G') were higher than the loss moduli (G″) over the whole frequency range for all the groups. The SEM results showed that fibrinogen/knob-g-HA hydrogels presented the heterogeneous mesh-like structures which were different from the honeycomb-like structures of fibrinogen/MA-HA hydrogels. Correspondingly, a higher swelling ratio was obtained in the groups of fibrinogen/knob-g-HA hydrogel. Finally, the cytocompatibility of fibrinogen/knob-g-HA hydrogels was proved by live/dead stainings and MTT assays in the 293T cells encapsulation test. All these results highlight the biological potential of the fibrinogen/knob-g-HA hydrogels for 3D cellular engineering.

PRP in OA knee - update, current confusions and future options

Positive results have been uniformly observed by various researchers for platelet-rich plasma (PRP) in early osteoarthritis (OA) knee in the past few years. PRP has clearly demonstrated its supremacy in comparison to hyaluronic acid (HA) and placebo in various clinical trials and is undoubtedly the best option available for symptomatic treatment in early OA. The release of growth factors from PRP occurs immediately and lasts for around three weeks and the clinical effect tends to wane down by the end of the year. Prolonged and sustained release of growth factors from platelets could possibly help in much better biological healing and sustained clinical effects. PRP in combination with biocompatible carriers could be one way of achieving this. Gelatin hydrogel PRP and chitosan PRP seem to be promising based on early in vitro studies and animal studies. PRP in combination with hyaluronic acid also seems to be additive. This article intends to discuss the present status of the PRP, confusions surrounding its use, upcoming trends and ideas for improvising PRP for use early OA knees based on available evidence.

Platelet-Rich Plasma Powder: A New Preparation Method for the Standardization of Growth Factor Concentrations

BACKGROUND

Platelet-rich plasma (PRP) is widely used in sports medicine. Available PRP preparations differ in white blood cell, platelet, and growth factor concentrations, making standardized research and clinical application challenging.

PURPOSE

To characterize a newly standardized procedure for pooled PRP that provides defined growth factor concentrations.

STUDY DESIGN

Controlled laboratory study.

METHODS

A standardized growth factor preparation (lyophilized PRP powder) was prepared using 12 pooled platelet concentrates (PCs) derived from different donors via apheresis. Blood samples and commercially available PRP (SmartPrep-2) served as controls (n = 5). Baseline blood counts were analyzed. Additionally, single PCs (n = 5) were produced by standard platelet apheresis. The concentrations of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), platelet-derived growth factor AB (PDGF-AB), transforming growth factor β1 (TGF-β1), insulin-like growth factor 1 (IGF-1), interleukin (IL)-1α, IL-1β, and IL-1 receptor agonist (IL-1RA) were analyzed by enzyme-linked immunosorbent assay, and statistical analyses were performed using descriptive statistics, mean differences, 95% CIs, and P values (analysis of variance).

RESULTS

All growth factor preparation methods showed elevated concentrations of the growth factors VEGF, bFGF, PDGF-AB, and TGF-β1 compared with those of whole blood. Large interindividual differences were found in VEGF and bFGF concentrations. Respective values (mean ± SD in pg/mL) for whole blood, SmartPrep-2, PC, and PRP powder were as follows: VEGF (574 ± 147, 528 ± 233, 1087 ± 535, and 1722), bFGF (198 ± 164, 410 ± 259, 151 ± 99, and 542), PDGF-AB (2394 ± 451, 17,846 ± 3087, 18,461 ± 4455, and 23,023), and TGF-β1 (14,356 ± 4527, 77,533 ± 13,918, 68,582 ± 7388, and 87,495). IGF-1 was found in SmartPrep-2 (1539 ± 348 pg/mL). For PC (2266 ± 485 pg/mL), IGF-1 was measured at the same levels of whole blood (2317 ± 711 pg/mL) but was not detectable in PRP powder. IL-1α was detectable in whole blood (111 ± 35 pg/mL) and SmartPrep-2 (119 ± 44 pg/mL).

CONCLUSION

Problems with PRP such as absent standardization, lack of consistency among studies, and black box dosage could be solved by using characterized PRP powder made by pooling and lyophilizing multiple PCs. The new PRP powder opens up new possibilities for PRP research as well as for the treatment of patients.

CLINICAL RELEVANCE

The preparation of pooled PRP by means of lyophilization may allow physicians to apply a defined amount of growth factors by using a defined amount of PRP powder. Moreover, PRP powder as a dry substance with no need for centrifugation could become ubiquitously available, thus saving time and staff resources in clinical practice. However, before transferring the results of this basic science study to clinical application, regulatory issues have to be cleared.

Comparison of intra-articular injection of plasma rich in growth factors versus hyaluronic acid following arthroscopy in the treatment of temporomandibular dysfunction: A randomised prospective study

PURPOSE

The main objective of our study was to evaluate the effectiveness of the injection of plasma rich in platelet-derived growth factors (PRGF) versus hyaluronic acid (HA) following arthroscopic surgery in patients diagnosed with internal derangement of the temporomandibular joint (TMJ) with osteoarthritis (OA).

MATERIALS AND METHODS

A total of 100 patients were randomised into two study groups. Group A (n = 50) received an injection of PRGF, and Group B (n = 50) received an injection of HA. The mean age was 35.5 years (range 18-77 years), and 88% of the patients were women. The pain intensity (visual analogue scale) and the extent of maximum mouth opening before and after the procedure were statistically analysed.

RESULTS

Better results were observed in the group treated with PRGF, with a significant reduction in pain at 18 months, compared with HA treatment. Regarding mouth opening, an increase was observed in both groups, with no significant difference.

CONCLUSIONS

The injection of PRGF following arthroscopy is more effective than the injection of HA with respect to pain in patients with advanced internal derangement of the TMJ.

Platelet-rich plasma and hyaluronic acid - an efficient biostimulation method for face rejuvenation

BACKGROUND

Cosmetic applications of platelet-rich plasma (PRP) are new, and reports are scarce and dispersed in the literature. There are a variety of commercially available kits and injection techniques, and the number and intervals of injections vary. New investigations should focus on developing a standardized procedure for PRP preparation and application methods to augment its efficacy and potency.

OBJECTIVES

In this report, we aim to provide data and commentary to assist and add to current guidelines.

METHODS

A series of 94 female patients with varying degrees of facial aging signs were treated with PRP and hyaluronic acid (HA). Mean age was 53.0 ± 5.6. The mean injection number was 3.6 ± 2.0. Platelet-poor and platelet- rich plasma parts were mixed with 0.5 cc %3.5 hyaluronic acid and 0.5 cc procaine and injected with a 30G, 13-mm needle into deep dermis and hypodermis. Patients were asked to rate their personal satisfaction with their skin texture, pigmentation, and sagging. In addition, the overall results were rated by three independent physicians and the patients themselves. The outcomes were peer-reviewed, and correlations between the degree of the aesthetic scores and the number of injections were explored.

RESULTS

There was a statistically significant difference in general appearance, skin firmness-sagging and skin texture according to the patients' before and after applications of PRP. A statistically significant correlation was found between the number of injections and overall satisfaction.

CONCLUSIONS

Compared to the baseline, the PRP and HA injections provided clinically visible and statistically significant improvement on facial skin. The improvements were more remarkable as the injection numbers increased.

Intra-articular Hyaluronic Acid (HA) and Platelet Rich Plasma (PRP) injection versus Hyaluronic acid (HA) injection alone in Patients with Grade III and IV Knee Osteoarthritis (OA): A Retrospective Study on Functional Outcome

Introduction: Intra-articular hyaluronic acid (HA) is widely utilized in the treatment of knee osteoarthritis whereas platelet rich plasma (PRP) enhances the regeneration of articular cartilage. This study analyses the efficacy of HA and PRP in grade III and IV knee osteoarthritis.

Methodology: This is a cross sectional study with retrospective review of 64 patients (101 knees) which includes 56 knees injected with HA+ PRP, and 45 knees with HA only.

Results: During the post six months International Knee Documentation Committee (IKDC) evaluation, HA+PRP group showed marked improvement of 24.33 compared to 12.15 in HA group. Decrement in visual analogue score (VAS) in HA+PRP was 1.9 compared to 0.8 in HA group.

Conclusion: We propose intra-articular HA and PRP injections as an optional treatment modality in Grade III and IV knee osteoarthritis in terms of functional outcome and pain control for up to six months when arthroplasty is not an option.

A new strategy to tackle severe knee osteoarthritis: Combination of intra-articular and intraosseous injections of Platelet Rich Plasma

INTRODUCTION

Knee osteoarthritis (KOA) is a mechanically induced, cytokine and enzyme-mediated disorder involving all the joint tissue of the knee. Rebuilding a physiological-homeostatic network at the tissue level following knee organ failure, such as in severe KOA, is a daunting task with therapeutic targets encompassing the articular cartilage, synovium and subchondral bone. Intraarticular infiltration of plasma rich in growth factors (PRP) has emerged as a promising symptomatic approach, although it is insufficient to reach the subchondral bone.

AREAS COVERED

This review addresses current molecular and cellular data in joint homeostasis and osteoarthritis pathophysiology. In particular, it focuses on changes that subchondral bone undergoes in knee osteoarthritis and evaluates recent observations on the crosstalk among articular cartilage, subchondral bone and synovial membrane. In addition, we review some mechanistic aspects that have been proposed and provide the rationale for using PRP intraosseously in KOA.

EXPERT OPINION

The knee joint is a paradigm of autonomy and connectedness of its anatomical structures and tissues from which it is made. We propose an innovative approach to the treatment of severe knee osteoarthritis consisting of a combination of intraarticular and intraosseous infiltrations of PRP, which might offer a new therapeutic tool in KOA therapy.

Intradiscal and intra-articular facet infiltrations with plasma rich in growth factors reduce pain in patients with chronic low back pain

Context:

Low back pain (LBP) is a complex and disabling condition, and its treatment becomes a challenge.

Aims:

The aim of our study was to assess the clinical outcome of plasma rich in growth factors (PRGF-Endoret) infiltrations (one intradiscal, one intra-articular facet, and one transforaminal epidural injection) under fluoroscopic guidance-control in patients with chronic LBP. PRGF-Endoret which has been shown to be an efficient treatment to reduce joint pain.

Settings and Design:

The study was designed as an observational retrospective pilot study. Eighty-six patients with a history of chronic LBP and degenerative disease of the lumbar spine who met inclusion and exclusion criteria were recruited between December 2010 and January 2012.

Subjects and Methods:

One intradiscal, one intra-articular facet, and one transforaminal epidural injection of PRGF-Endoret under fluoroscopic guidance-control were carried out in 86 patients with chronic LBP in the operating theater setting.

Statistical Analysis Used:

Descriptive statistics were performed using absolute and relative frequency distributions for qualitative variables and mean values and standard deviations for quantitative variables. The nonparametric Friedman statistical test was used to determine the possible differences between baseline and different follow-up time points on pain reduction after treatment.

Results:

Pain assessment was determined using a visual analog scale (VAS) at the first visit before (baseline) and after the procedure at 1, 3, and 6 months. The pain reduction after the PRGF-Endoret injections showed a statistically significant drop from 8.4 ± 1.1 before the treatment to 4 ± 2.6, 1.7 ± 2.3, and 0.8 ± 1.7 at 1, 3, and 6 months after the treatment, respectively, with respect to all the time evaluations (P < 0.0001) except for the pain reduction between the 3^rd and 6^th month whose signification was lower (P < 0.05). The analysis of the VAS over time showed that at the end point of the study (6 months), 91% of patients showed an excellent score, 8.1% showed a moderate improvement, and 1.2% were in the inefficient score.

Conclusions:

Fluoroscopy-guided infiltrations of intervertebral discs and facet joints with PRGF in patients with chronic LBP resulted in significant pain reduction assessed by VAS.

Efficacy and safety profile of a compound composed of platelet-rich plasma and hyaluronic acid in the treatment for knee osteoarthritis (preliminary results)

BACKGROUND

The combined use of hyaluronic acid and platelet-rich plasma has never been reported in the treatment for osteoarthritis. Aim of this paper was to evaluate the efficacy of this association and to compare retrospectively these results with those of a cohort of patients treated with platelet-rich plasma only.

MATERIALS AND METHODS

Subjects with mild-to-moderate knee osteoarthritis were enrolled. After clinical and ultrasound evaluation, patients received a weekly intra-articular injection of 2 ml of hyaluronic acid added with 2 ml of platelet-rich plasma for 3 weeks. Follow-up was performed at 1, 3, and 6 months. The same clinical parameters were retrospectively collected from a cohort of patients treated with 4-5 ml of platelet-rich plasma only.

RESULTS

Forty knees were treated in both groups. The intra-group comparison showed a significant improvement in clinical and functional outcomes at 1, 3, and 6 months, while the infra-group comparison did not show any significant difference.

CONCLUSIONS

The association of platelet-rich plasma + hyaluronic acid has the same efficacy of platelet-rich plasma only, administered in higher volume. We may infer that hyaluronic acid works synergically and improves the activity of several molecules contained in platelet-rich plasma.

Platelet-Rich Plasma Prolongs Myofibroblast Accumulation in Corneal Stroma with Incisional Wound

PURPOSE

The purpose of this study was to determine whether platelet-rich plasma (PRP) has an effect on corneal stromal cells in a rat model of wound healing following corneal incision.

MATERIALS AND METHODS

The effect of PRP on corneal wound healing in vivo was investigated in a corneal incision wound model in rats. 40 rats were wounded by deep corneal incision, and treated with either topically administered PRP (20 rats) or sodium chloride (20 rats). At 4 h and 1, 3, and 5 days after incision, α-smooth muscle actin (α SMA), SMAD2 and SMAD3 expression and apoptosis in stromal cells were evaluated by immunohistochemistry, and IL-1β mRNA expression was evaluated by real time PCR.

RESULTS

PRP-treated corneas exhibited reduced stromal cell apoptosis at day 3 and day 5 (p = 0.038, and <0.001, respectively) relative to controls. Interleukin-1β mRNA expression, however, was unchanged in PRP-treated corneas relative to controls. Topical PRP treatment resulted in a higher proportion of αSMA-positive myofibroblasts recruited to the wound site relative to control corneas. PRP did not affect activation of SMAD2 but activation of SMAD3 was significantly reduced at day 1 (p = 0.001) and dramatically increased at day 5 (p = 0.032).

CONCLUSIONS

PRP treatment resulted in suppressed stromal cell apoptosis followed by SMAD3 activation and a greater proportion of myofibroblasts present at the wound site. Suppression of stromal cell apoptosis after corneal wounding by use of a growth factor-rich formulation may lead to myofibroblast accumulation by modulation of the TGF-β pathway.

Circadian variation of growth factor levels in platelet-rich plasma

OBJECTIVE

The influence of circadian rhythms has recently been considered in advanced studies of chronopharmacology and chronotherapeutics. Although emerging studies have reported the usefulness of platelet-rich plasma (PRP), no reports have described the diurnal variations in PRP growth factor levels. In the present study, we hypothesized that growth factor levels in PRP show a significant diurnal variation.

DESIGN

Controlled laboratory study.

SETTING

Institutional.

PARTICIPANTS

Ten adult male volunteers (mean age, 30.0 ± 2.6 years; range, 26-34 years).

INTERVENTIONS

Each subject donated a 20-mL sample of fasting blood, 4 times per day (7 AM, 11 AM, 3 PM, and 7 PM).

MAIN OUTCOME MEASURES

Each blood sample was processed to produce PRP. Complete blood counts of peripheral blood (PB) and PRP, as well as quantitative determination of PRP growth factor levels (platelet-derived growth factor and transforming growth factor) were performed. Statistical analyses were conducted using a one-way repeated measures analysis of variance.

RESULTS

No significant differences were observed in platelet, white blood cell, and red blood cell counts in the PB or in the PRP samples throughout the course of the day. In addition, there were no significant differences in PRP growth factor levels at the various time points.

CONCLUSIONS

Significant diurnal variations in platelet counts and growth factor levels were not observed in PRP. Therefore, adjustments for diurnal variation in chronotherapy may not be important when PRP is used in clinical practice.

Comparison between two different platelet-rich plasma preparations and control applied during anterior cruciate ligament reconstruction. Is there any evidence to support their use?

INTRODUCTION

To compare the clinical, analytical and graft maturation effects of two different platelet-rich plasma (PRP) preparations applied during anterior cruciate ligament (ACL) reconstruction.

MATERIALS AND METHODS

A total of 150 patients with ACL disruption were included in the study. Arthroscopic ACL reconstruction with patellar tendon allograft was conducted on all knees using the same protocol. One hundred patients were prospectively randomised to either a group to receive double-spinning platelet-enriched gel (PRP) with leukocytes (n=50) or to a non-gel group (n=50). Finally, we included 50 patients treated with a platelet-rich preparation from a single-spinning procedure (PRGF Endoret(®) Technology) without leukocytes. Inflammatory parameters, including C-reactive protein (CRP) and knee perimeters (PER), were measured 24 hours and 10 days after surgery. Postoperative pain score (visual analogue score [VAS]) was recorded the day after surgery. Follow-up visits occurred postoperatively at 3, 6, and 12 months. The International Knee Documentation Committee scale (IKDC) was included to compare functional state, and MRI was conducted 6 months after surgery.

RESULTS

The PRGF group showed a statistically significant improvement in swelling and inflammatory parameters compared with the other two groups at 24 hours after surgery (p<0.05). The results did not show any significant differences between groups for MRI and clinical scores.

CONCLUSIONS

PRGF used in ACL allograft reconstruction was associated with reduced swelling; however, the intensity and uniformity of the graft on MRI were similar in the three groups, and there was no clinical or pain improvement compared with the control group.

LEVEL OF EVIDENCE

II.

Influence of TNF-α and biomechanical stress on matrix metalloproteinases and lysyl oxidases expressions in human knee synovial fibroblasts

PURPOSE

It was reported that not only ACL but also the synovium may be the major regulator of matrix metalloproteinases (MMPs) in synovial fluids after ACL injury. In order to further confirm whether synovium is capable of regulating the microenvironment in the process of ACL injury, the complicated microenvironment of joint cavity after ACL injury was mimicked and the combined effects of mechanical injury and inflammatory factor [tumour necrosis factor-α (TNF-α)] on expressions of lysyl oxidases (LOXs) and MMPs in synovial fibroblasts derived from normal human synovium were studied.

METHODS

Human normal knee joint synovial fibroblasts were stimulated for 1-6 h with mechanical stretch and inflammatory factor (TNF-α). Total RNA was harvested, reverse transcribed and assessed by real-time polymerase chain reaction for the expression of LOXs and MMP-1, 2, 3 messenger RNAs. MMP-2 activity was assayed from the collected culture media samples using zymography.

RESULTS

Compared to control group, our results showed that 6% physiological stretch increased MMP-2 and LOXs (except LOXL-3), decreased MMP-1 and MMP-3; injurious stretch (12%) decreased LOXs (except LOXL-2)and increased MMP-1, 2 and 3; the combination of injurious stretch and TNF-α decreased LOXs and increased MMP-1, 2 and 3 in synovial fibroblasts in a synergistical manner.

CONCLUSION

This study demonstrated that combination of mechanical injury and inflammatory factors up-regulated the expressions of MMPs and down-regulated the expressions of LOXs in synovial fibroblasts, eventually alter the balance of tissue healing. Thus, synovium may be involved in regulating the microenvironment of joint cavity. Based on the mechanism, early interventions to inhibit the production of MMPs or promote the production of LOXs in the synovial fibroblasts should be performed to facilitate the healing of tissue.

Knee osteoarthritis: hyaluronic acid, platelet-rich plasma or both in association?

INTRODUCTION

Bidirectional interactions between cells and fluidic surroundings regulate cellular functions and maintain tissue or organ architecture. Accordingly, the synovial fluid is the primary source of environmental signals and determines to a great extent the molecular interactions within the joint capsule, both in homeostasis and pathology.

AREAS COVERED

We provided an update on hyaluronic acid (HA) and platelet-rich plasma (PRP) concepts necessary to build the rationale for creating a combined treatment. The information is based on a PubMed search using the terms 'platelet-rich plasma', 'hyaluronic acid', 'knee pathology', 'knee osteoarthritis' (OA).

EXPERT OPINION

In OA, a deleterious fluidic microenvironment is established, with presence of HA fragments, catabolic enzymes and inflammatory molecules. The central concept underlying intra-articular injection is to modify deleterious fluidic microenvironments. PRP administration has shown pain remission and function improvement, but less than half of the patients showed clinically significant improvement. PRP exceeds HA, the comparator used in PRP clinical trials, albeit both HA and PRP alleviate symptoms in mild-to-moderate OA patients. Combining PRP and HA may benefit from their dissimilar biological mechanisms and help in controlling delivery and presentation of signaling molecules. Three armed randomized studies, using both HA and PRP as comparators, will provide information about the impact of this approach.

The effects of plasma rich in growth factors (PRGF-Endoret) on healing of medial collateral ligament of the knee

PURPOSE

Platelet-rich plasma (PRP) has been increasingly used in sports-related injuries for therapeutic applications. However, there are numerous manufacturing procedures and treatment protocols of PRP use, which make difficult to assess its real efficacy for tissue healing. This study addressed to evaluate the therapeutic effects of locally delivered plasma rich in growth factors (PRGF-Endoret) on the early healing of medial collateral ligament (MCL) in rabbit knees.

METHODS

Thirty-one Japanese white rabbits were subjected to a mop-end tear in the MCL of the left knee. PRGF-Endoret was prepared using Anitua's technique. Two groups were set up. In 17 knees, prepared 1.0 ml of PRGF-Endoret after clotting was applied on the tear site, while in 14 knees the tear site was untreated serving as a control. Quantitative aspects of PRGF-Endoret, the concentration of platelets, leukocytes and erythrocytes and therapeutic growth factors such as PDGF-BB and TGF-β1 were measured. Rabbits were sacrificed at 3 and 6 weeks after the operation and histological and biomechanical evaluation were performed.

RESULTS

No leukocytes were measured and certain amount of growth factors such as PDGF-BB and TGF-β1 were confirmed in the PRGF-Endoret. PRGF-Endoret stimulated proliferation of fibroblasts and neovascularization, and induced statistically better structural properties in repaired MCL.

CONCLUSIONS

Our findings provide evidence that local administration of PRGF-Endoret promotes early steps in ligament healing and the repair of structural properties in a rabbit model. PRGF-Endoret would be a useful product in clinical treatment of ligament injuries.

A biological therapy to osteoarthritis treatment using platelet-rich plasma

INTRODUCTION

Osteoarthritis (OA) is a degenerative disease affecting the synovial joint. It is caused by cells exposure to non-physiological stimuli, either mechanical or biochemical, and the loss of bone-cartilage homeostasis. Some of these changes, however, may be reversed by the use of single or combined growth factors, suggesting that the treatment of OA could be addressed using a pool of growth factors.

AREAS COVERED

This review addresses current molecular and biological knowledge and implicates the recapitulation of some developmental processes during endochondral ossification in OA aetiology and pathogenesis. Platelets act as carriers of endogenous morphogens that may modulate cell fate and therefore affect joint tissues structure and function. We shed light on the platelet-rich plasma effects on biological level that might drive the osteoarthritic joint's improvement both in structure and function.

EXPERT OPINION

We present the therapeutic potential of plasma rich in growth factors (PRGF-Endoret), an endogenous biological therapy that might modulate the gene expression of cells such as chondrocytes, synoviocytes, macrophages, and mesenchymal stem cells, and thereby influence an anabolic microenvironment of synovial joint which is conducive to maintaining the homeostatic state of the joint's tissues, and hence reduce pain and improve the joint motion.