Platelet-Rich Plasma and Cartilage Repair

The Nrf2/HO-1 pathway participates in the antiapoptotic and anti-inflammatory effects of platelet-rich plasma in the treatment of osteoarthritis

INTRODUCTION

We aimed to explore the molecular mechanisms through which platelet-rich plasma (PRP) attenuates osteoarthritis (OA)-induced pain, apoptosis, and inflammation.

METHODS

An in vivo model of OA was established by injuring rats using the anterior cruciate ligament transection method, whereas an in vitro model was generated by exposing chondrocytes to interleukin (IL)-1β. Both models were then treated with PRP.

RESULTS

In both the in vivo and in vitro models, OA led to the suppression of the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway, whereas treatment with PRP reactivated this molecular axis. Inhibition of the Nrf2/HO-1 pathway using the Nrf2 inhibitor brusatol or through Nrf2 gene silencing counteracted the effects of PRP in reducing the tenderness and thermal pain thresholds of OA rats. Additionally, PRP reduced the mRNA expression of IL-1β, IL-6, tumor necrosis factor-alpha (TNF-α), and matrix metallopeptidase 13 (MMP-13) and the protein expression of B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X-protein (Bax), and caspase-3. Furthermore, inflammation and apoptosis were induced by brusatol treatment or Nrf2 silencing. Additionally, in the in vitro model, PRP treatment increased the proliferation of chondrocytes and attenuated their inflammatory response and apoptosis, effects that were abrogated by Nrf2 depletion.

CONCLUSIONS

The Nrf2/HO-1 pathway participates in the PRP-mediated attenuation of OA development by suppressing inflammation and apoptosis.

Assessment of the Quality and Readability of Information Provided by ChatGPT in Relation to the Use of Platelet-Rich Plasma Therapy for Osteoarthritis

Objective: This study aimed to evaluate the quality and readability of information generated by ChatGPT versions 3.5 and 4 concerning platelet-rich plasma (PRP) therapy in the management of knee osteoarthritis (OA), exploring whether large language models (LLMs) could play a significant role in patient education. Design: A total of 23 common patient queries regarding the role of PRP therapy in knee OA management were presented to ChatGPT versions 3.5 and 4. The quality of the responses was assessed using the DISCERN criteria, and readability was evaluated using six established assessment tools. Results: Both ChatGPT versions 3.5 and 4 produced moderate quality information. The quality of information provided by ChatGPT version 4 was significantly better than version 3.5, with mean DISCERN scores of 48.74 and 44.59, respectively. Both models scored highly with respect to response relevance and had a consistent emphasis on the importance of shared decision making. However, both versions produced content significantly above the recommended 8th grade reading level for patient education materials (PEMs), with mean reading grade levels (RGLs) of 17.18 for ChatGPT version 3.5 and 16.36 for ChatGPT version 4, indicating a potential barrier to their utility in patient education. Conclusions: While ChatGPT versions 3.5 and 4 both demonstrated the capability to generate information of moderate quality regarding the role of PRP therapy for knee OA, the readability of the content remains a significant barrier to widespread usage, exceeding the recommended reading levels for PEMs. Although ChatGPT version 4 showed improvements in quality and source citation, future iterations must focus on producing more accessible content to serve as a viable resource in patient education. Collaboration between healthcare providers, patient organizations, and AI developers is crucial to ensure the generation of high quality, peer reviewed, and easily understandable information that supports informed healthcare decisions.

Most Publications Regarding Platelet-Rich Plasma Use in the Knee Are From Asia, Investigate Injection for Osteoarthritis, and Show Outcome Improvement: A Scoping Review

PURPOSE

To evaluate and synthesize the available literature related to platelet-rich plasma (PRP) treatment of knee pathologies and to provide recommendations to inform future research in the field.

METHODS

PubMed, CINAHL, and Scopus databases were queried on October 6, 2023. All identified citations were collated and uploaded into Covidence for screening and data extraction. Studies were included if they were human studies published in English with adult cohorts that received PRP as a procedural injection or surgical augmentation for knee pathologies with patient-reported outcome measures (PROMs) and level of evidence Levels I-IV.

RESULTS

Our search yielded 2,615 studies, of which 155 studies from 2006 to 2023 met the inclusion criteria. Median follow-up was 9 months (±11.2 months). Most studies (75.5%) characterized the leukocyte content of PRP, although most studies (86%) did not use a comprehensive classification scheme. In addition, most studies were from Asia (50%) and Europe (32%) and were from a single center (96%). In terms of treatment, 74% of studies examined PRP as a procedural injection, whereas 26% examined PRP as an augmentation. Most studies (68%) examined treatment of knee osteoarthritis. Many studies (83%) documented significant improvements in PROMs, including 93% of Level III/IV evidence studies and 72% of Level I/II evidence studies, although most studies (70%) failed to include minimal clinically important difference values. The visual analog scale was the most-used PROM (58% of studies), whereas the Short Form Health Survey 36-item was the least-used PROM (5% of studies).

CONCLUSIONS

Most published investigations of knee PRP are performed in Asia, investigate procedural injection for osteoarthritis, and show significant outcome improvements. In addition, this review highlights the need for better classification of PRP formulations.

LEVEL OF EVIDENCE

Level IV, scoping Review of level I-IV studies.

Long term improvement of knee osteoarthritis after injection of single high/very high volume of very pure PRP: A retrospective analysis of patients optimally managed in dedicated centers

Introduction

PRP is gaining increasing interest for pain relief and improvement of joint function in patients with knee osteoarthritis (KOA) but practices and results remain heterogeneous limiting its adoption as standard of care. Current international recommendations are to collect real-life evidence of efficacy with a systematic monitoring of PRP quality and patients' outcomes. We aimed to analyze the response of patients presenting KOA and treated with standardized PRP injection in routine care. We also investigated the potential contributing factors including patient's phenotype and PRP characteristics.

Methods

Patients with symptomatic KOA and that failed first-line therapy received a single injection of a qualified PRP prepared using medical devices allowing to recover a high/very high volume of very pure PRP. Visual analogue scale (VAS) and Western Ontario and McMaster Osteoarthritis Index (WOMAC) score were recorded at baseline and during 18 months follow-up.

Results

431 patients had available follow-up data at 3 months, 291 at 6 months, 137 at 12 months and 44 at 18 months. PRP induced a significant decrease of WOMAC score at all follow up endpoints (29.2 ± 19.2 at 3 months, p < 0.001 and 25.9 ± 19.7 at 12 months, p < 0.01, compared to 39.7 ± 18.9 at baseline). Similar results were observed for pain VAS (38.9 ± 23.3 at 3 months, p < 0.001 and 35.3 ± 24.1 at 12 months, p < 0.05, compared to 56.0 ± 20.7 at baseline). Changes at 12 months were correlated to baseline scores and to the level of improvement at 3 months. The proportion of OMERACT OARSI responders reached 56.2 % for the total cohort and 60.4 % for severe patients at 6 months. Treatment failure occurred for 8.4 % of patients. Age, BMI or Kellgren-Lawrence grade did not impact on efficacy.

Conclusion

This real-life study evidences the clinical benefit of a standardized high or very high-volume injection of very pure PRP in patients with KOA, including those with a severe grade. It opens perspectives in the positioning of such strategy to delay arthroplasty and provide insights on factors able to anticipate long term efficacy.

The Synergistic Effects of Hyaluronic Acid and Platelet-Rich Plasma for Patellar Chondropathy

Musculoskeletal disorders are increasingly prevalent worldwide, causing significant socioeconomic burdens and diminished quality of life. Notably, patellar chondropathy (PC) is among the most widespread conditions affecting joint structures, resulting in profound pain and disability. Hyaluronic acid (HA) and platelet-rich plasma (PRP) have emerged as reliable, effective, and minimally invasive alternatives. Continuous research spanning from laboratory settings to clinical applications demonstrates the numerous advantages of both products. These encompass lubrication, anti-inflammation, and stimulation of cellular behaviors linked to proliferation, differentiation, migration, and the release of essential growth factors. Cumulatively, these benefits support the rejuvenation of bone and cartilaginous tissues, which are otherwise compromised due to the prevailing degenerative and inflammatory responses characteristic of tissue damage. While existing literature delves into the physical, mechanical, and biological facets of these products, as well as their commercial variants and distinct clinical uses, there is limited discussion on their interconnected roles. We explore basic science concepts, product variations, and clinical strategies. This comprehensive examination provides physicians with an alternative insight into the pathophysiology of PC as well as biological mechanisms stimulated by both HA and PRP that contribute to tissue restoration.

Biological intra-articular augmentation for osteotomy in knee osteoarthritis: strategies and results : A systematic review of the literature from the ESSKA Orthobiologics Initiative

PURPOSE

To assess whether there is evidence supporting the use of augmentation strategies, either cartilage surgical procedures or injective orthobiologic options, to improve the results of osteotomies in knees with osteoarthritis (OA).

METHODS

A systematic review of the literature was performed on the PubMed, Web of Science and the Cochrane databases in January 2023 on osteotomies around the knee associated with augmentation strategies (either cartilage surgical procedures or injective orthobiologic options), reporting clinical, radiological, or second-look/histological outcomes at any follow-up. The methodological quality of the included studies was assessed with the Coleman Methodology Score (CMS).

RESULTS

Out of the 7650 records identified from the databases, 42 articles were included for a total of 3580 patients and 3609 knees treated; 33 articles focused on surgical treatments and 9 on injective treatments performed in association with knee osteotomy. Out of the 17 comparative studies with surgical augmentation, only 1 showed a significant clinical benefit of an augmentation procedure with a regenerative approach. Overall, other studies showed no differences with reparative techniques and even detrimental outcomes with microfractures. Regarding injective procedures, viscosupplementation showed no improvement, while the use of platelet-rich plasma or cell-based products derived from both bone marrow and adipose tissue showed overall positive tissue changes which translated into a clinical benefit. The mean modified CMS score was 60.0 ± 12.1.

CONCLUSION

There is no evidence to support the effectiveness of cartilage surgical treatments combined with osteotomies in terms of pain relief and functional recovery of patients affected by OA in misaligned joints. Orthobiologic injective treatments targeting the whole joint environment showed promising findings. However, overall the available literature presents a limited quality with only few heterogeneous studies investigating each treatment option. This ORBIT systematic analysis will help surgeons to choose their therapeutic strategy according to the available evidence, and to plan further and better studies to optimize biologic intra-articular osteotomy augmentation.

LEVEL OF EVIDENCE

Level IV.

Methods of Conservative Intra-Articular Treatment for Osteoarthritis of the Hip and Knee

BACKGROUND

Osteoarthritis is a degenerative joint disease that is becoming increasingly common as the population ages. Conservative treatment for hip or knee osteoarthritis has been limited to pain control. Intra-articular injections for targeted local treatment have been widely used in clinical practice for many years.

METHODS

This review is based on publications retrieved by a selective literature search, including recent meta-analyses, systematic reviews, randomized controlled trials (RCTs), and current guidelines.

RESULTS

In Germany, the 12-month prevalence of osteoarthritis in adults is 17.9%. Conservative treatments are intended to alleviate symptoms and do not affect the progression of the disease. Glucocorticoids can be used to relieve otherwise intractable pain in the short term, but their prolonged use increases the risk of cartilage loss and progression of osteoarthritis. According to multiple guidelines, there is only weak evidence for the use of hyaluronic acid. Evidence does exist that high-molecular-weight hyaluronic acid may lead to better outcomes than the low-molecular-weight form. RCTs have revealed no more than short-term clinical efficacy for a variety of specific therapeutic approaches, including the use of cytokine inhibitors. Other treatments, e.g., with platelet-enriched plasma, aspirates from bone marrow or adipose tissue, or expanded mesenchymal stromal cells (MSC), have not been found to have clinically relevant long-term effects.

CONCLUSION

In view of the scant available evidence, further standardized RCTs will be needed to give a more comprehensive picture of the efficacy of intra-articular treatments for hip and knee osteoarthritis.

Platelet-Rich Plasma Power-Mix Gel (ppm)-An Orthobiologic Optimization Protocol Rich in Growth Factors and Fibrin

Platelet- and fibrin-rich orthobiologic products, such as autologous platelet concentrates, have been extensively studied and appreciated for their beneficial effects on multiple conditions. Platelet-rich plasma (PRP) and its derivatives, including platelet-rich fibrin (PRF), have demonstrated encouraging outcomes in clinical and laboratory settings, particularly in the treatment of musculoskeletal disorders such as osteoarthritis (OA). Although PRP and PRF have distinct characteristics, they share similar properties. The relative abundance of platelets, peripheral blood cells, and molecular components in these orthobiologic products stimulates numerous biological pathways. These include inflammatory modulation, augmented neovascularization, and the delivery of pro-anabolic stimuli that regulate cell recruitment, proliferation, and differentiation. Furthermore, the fibrinolytic system, which is sometimes overlooked, plays a crucial role in musculoskeletal regenerative medicine by regulating proteolytic activity and promoting the recruitment of inflammatory cells and mesenchymal stem cells (MSCs) in areas of tissue regeneration, such as bone, cartilage, and muscle. PRP acts as a potent signaling agent; however, it diffuses easily, while the fibrin from PRF offers a durable scaffolding effect that promotes cell activity. The combination of fibrin with hyaluronic acid (HA), another well-studied orthobiologic product, has been shown to improve its scaffolding properties, leading to more robust fibrin polymerization. This supports cell survival, attachment, migration, and proliferation. Therefore, the administration of the "power mix" containing HA and autologous PRP + PRF may prove to be a safe and cost-effective approach in regenerative medicine.

Multifactorial assessment of leukocyte reduced platelet rich plasma injection in dogs undergoing tibial plateau leveling osteotomy: A retrospective study

This study assessed the effects of concurrent intra-articular injection and Tibial Plateau Leveling Osteotomy (TPLO) plate surface treatment with leukoreduced platelet rich plasma (lPRP) on outcomes of dogs undergoing TPLO. A retrospective study of medical records for cases presenting from January 2018 to December 2020 was performed. Client-owned dogs with naturally occurring cranial cruciate ligament rupture that underwent TPLO surgery were divided into two groups. The lPRP group included cases that underwent intra-articular injection and plate surface treatment at the time of their TPLO. The control group (C) underwent TPLO without PRP treatment. Data analyzed included: presence of surgical site infection, implant removal rate, degree of change in OA progression score, lameness score progression and radiographic bone healing. The short- and long-term complication rate, hospitalization and antibiotic therapy were also compared between the groups. Descriptive statistics, comparison analyses (Chi square test, t-test, Fisher's exact test) and multi-level logistic regression models were used for statistical analysis. A total of 110 cases met the study inclusion criteria: 54 = lPRP, 56 = C. There were no significant differences between groups with regard to gender, age, presence of meniscal tear, weight, or body condition score. Significant findings included: improved radiographic healing of the osteotomy in the lPRP group, improved global OA scores in the lPRP group, and improved lameness score at recheck examination in the lPRP group. There was no significant difference between the lPRP and C group with regard to surgical site infection and implant removal rate. Concurrent intra-articular injection and plate surface treatment with leukocyte reduced PRP at the time of TPLO, is beneficial in slowing the progression of OA, hastening the radiographic evidence of osteotomy healing, and improved lameness score on recheck examination. Leukocyte reduced PRP was not a significant factor in reducing SSI or implant removal rate.

Porcine Platelet Lysate Intra-articular Knee Joint Injections for the Treatment of Rabbit Cartilage Lesions and Osteoarthritis

Purpose

At present, autologous platelet-derived therapies such as platelet-rich plasma is widely used in the clinic, but allogeneic and xenogeneic therapies are currently in the research stage, mainly due to their biocompatibility in vivo. Platelet lysates depleted of antigens such as blood cells are a potential solution for allogeneic or xenogeneic applications. Platelet lysates can successfully promote the growth and differentiation of xenogeneic cells in vitro, but in vivo data are not yet available. This study aims to evaluate whether porcine platelet lysate can effectively avoid inflammatory reaction in rabbit knee joint, and then treat cartilage defect and arthritis.

Methods

We developed porcine platelet lysates containing undetectable antigens such as blood cells and complement. For xenogeneic application, platelet lysate was injected into rabbit knee joints to observe joint responses. To examine cartilage repair, osteochondral defects were created in rabbit knee joints. Rabbits were sacrificed three months after treatment with platelet lysate to observe cartilage regeneration and arthritis.

Results

The tissue sections in the rabbit knee joints showed no inflammatory reaction. Furthermore, the injection of platelet lysate was found to effectively inhibit the formation of cartilage arthritis in rabbit knee joints.

Conclusion

Our experimental results show that xenogeneic platelet lysate is a safe and effective method in the treatment of arthritis, which can be used as a research basis for future medical applications. The use of xenogeneic platelet lysate for regenerative therapy in vivo is feasible.

Clinical Efficacy of Intra-Articular Injection with P-PRP Versus that of L-PRP in Treating Knee Cartilage Lesion: A Randomized Controlled Trial

OBJECTIVE

Platelet-rich plasma（PRP), with different concentration of leukocytes, may lead to varying effects in the treatment of cartilage lesions. So far, current research has not shown enough evidence on this. To evaluate the clinical efficacy and safety of intra-articular injection with pure platelet-rich plasma (P-PRP) versus those of leukocyte platelet-rich plasma (L-PRP) in treating knee cartilage lesions, we conducted a double-blind, randomized controlled clinical trial with a larger sample and longer follow-up period.

METHODS

From October 2019 to October 2020, 95 patients were invited to participate in our study, and 60 (63.2%) were randomized to P-PRP (n = 30) or L-PRP (n = 30) groups. Patients from the two groups were treated with knee intra-articular injections of P-PRP or L-PRP. Visual analog scale (VAS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were assessed using an unpaired t-test for independent samples preoperatively and at 6 weeks, 12 weeks, 6 months, and 12 months after intervention.

RESULTS

We followed up 27 cases in the P-PRP group and 26 cases in the L-PRP group. No significant differences in VAS and WOMAC scores were found between the two groups before the intervention (p > 0.05). The WOMAC Pain and VAS-Motions scores of the P-PRP group were significantly lower than those of the L-PRP group at 6 weeks after the intervention (p < 0.05). While the long-term clinical efficacy of both injections was similar and weakened after 12 months, more adverse events were found in the L-PRP group.

CONCLUSIONS

The short-term results demonstrate a positive effect in reducing pain and improving function in patients with knee cartilage lesions in the two groups. While the P-PRP injection showed better clinical efficacy in the early phase of postoperative rehabilitation and resulted in fewer adverse events, long-term follow-up showed similar and weakened efficacy after 12 months.

TRIAL REGISTRATION

ChiCTR1900026365. Registered on October 3, 2019, http://www.chictr.org.cn/showproj.aspx?proj=43911.

Intra-osseous plasma rich in growth factors enhances cartilage and subchondral bone regeneration in rabbits with acute full thickness chondral defects: Histological assessment

Background

Intra-articular (IA) combined with intra-osseous (IO) infiltration of plasma rich in growth factors (PRGF) have been proposed as an alternative approach to treat patients with severe osteoarthritis (OA) and subchondral bone damage. The aim of the study is to evaluate the efficacy of IO injections of PRGF to treat acute full depth chondral lesion in a rabbit model by using two histological validated scales (OARSI and ICRS II).

Methodology

A total of 40 rabbits were included in the study. A full depth chondral defect was created in the medial femoral condyle and then animals were divided into 2 groups depending on the IO treatment injected on surgery day: control group (IA injection of PRGF and IO injection of saline) and treatment group (IA combined with IO injection of PRGF). Animals were euthanized 56 and 84 days after surgery and the condyles were processed for posterior histological evaluation.

Results

Better scores were obtained in treatment group in both scoring systems at 56- and 84-days follow-up than in control group. Additionally, longer-term histological benefits have been obtained in the treatment group.

Conclusions

The results suggests that IO infiltration of PRGF enhances cartilage and subchondral bone healing more than the IA-only PRGF infiltration and provides longer-lasting beneficial effects.

Individual immune cell and cytokine profiles determine platelet-rich plasma composition

OBJECTIVE

Platelet-rich plasma (PRP) therapy is increasingly popular to treat musculoskeletal diseases, including tendinopathies and osteoarthritis (OA). To date, it remains unclear to which extent PRP compositions are determined by the immune cell and cytokine profile of individuals or by the preparation method. To investigate this, we compared leukocyte and cytokine distributions of different PRP products to donor blood samples and assessed the effect of pro-inflammatory cytokines on chondrocytes.

DESIGN

For each of three PRP preparations (ACP®, Angel™, and nSTRIDE® APS), products were derived using whole blood samples from twelve healthy donors. The cellular composition of PRP products was analyzed by flow cytometry using DURAClone antibody panels (DURAClone IM Phenotyping Basic and DURAClone IM T Cell Subsets). The MESO QuickPlex SQ 120 system was used to assess cytokine profiles (V-PLEX Proinflammatory Panel 1 Human Kit, Meso Scale Discovery). Primary human chondrocyte 2D and 3D in vitro cultures were exposed to recombinant IFN-γ and TNF-α. Proliferation and chondrogenic differentiation were quantitatively assessed.

RESULTS

All three PRP products showed elevated portions of leukocytes compared to baseline levels in donor blood. Furthermore, the pro-inflammatory cytokines IFN-γ and TNF-α were significantly increased in nSTRIDE® APS samples compared to donor blood and other PRP products. The characteristics of all other cytokines and immune cells from the donor blood, including pro-inflammatory T cell subsets, were maintained in all PRP products. Chondrocyte proliferation was impaired by IFN-γ and enhanced by TNF-α treatment. Differentiation and cartilage formation were compromised upon treatment with both cytokines, resulting in altered messenger ribonucleic acid (mRNA) expression of collagen type 1A1 (COL1A1), COL2A1, and aggrecan (ACAN) as well as reduced proteoglycan content.

CONCLUSIONS

Individuals with elevated levels of cells with pro-inflammatory properties maintain these in the final PRP products. The concentration of pro-inflammatory cytokines strongly varies between PRP products. These observations may help to unravel the previously described heterogeneous response to PRP in OA therapy, especially as IFN-γ and TNF-α impacted primary chondrocyte proliferation and their characteristic gene expression profile. Both the individual's immune profile and the concentration method appear to impact the final PRP product.

TRIAL REGISTRATION

This study was prospectively registered in the Deutsches Register Klinischer Studien (DRKS) on 4 November 2021 (registration number DRKS00026175).

Intra-osseous infiltration of adipose mesenchymal stromal cells and plasma rich in growth factors to treat acute full depth cartilage defects in a rabbit model: Serum osteoarthritis biomarkers and macroscopical assessment

Introduction

Intra-articular infiltration of plasma rich in growth factors (PRGF) and adipose mesenchymal stromal cells (AMSCs) are known to inhibit osteoarthritis progression. However, in severely affected patients, the treatment cannot reach the deeper layers of the articular cartilage; thus, its potential is limited. To overcome this limitation, intra-osseous infiltrations have been suggested. The purpose of this study is to assess the impact of intra-osseous infiltration therapies on serum biomarkers of osteoarthritis and to assess cartilage regeneration macroscopically.

Materials and methods

A total of 80 rabbits were divided into four groups based on the intra-osseous treatment administered on the day of surgery: control, PRGF, AMSCs and a combination of PRGF + AMSCs. In addition, all groups received a single intra-articular administration of PRGF on the same day. Serum biomarker levels were measured before infiltration and 28-, 56-, and 84-days post infiltration, and macroscopical assessment was conducted at 56- and 84-days follow-up post infiltration.

Results

In the PRGF + AMSCs group, significantly lower concentrations of hyaluronic acid and type II collagen cleavage neoepitope were recorded at all time points during the study, followed by PRGF, AMSCs and control groups. Regarding macroscopical assessment, lower scores were obtained in PRGF + AMSCs group at all study times.

Discussion

The results suggest that the combination of intra-articular PRGF with intra-osseous PRGF or AMSCs achieves better results in rabbits with acute chondral defects and that intra-osseous infiltration is a safe procedure.

Platelet-rich plasma use for hip and knee osteoarthritis in the United States

BACKGROUND

Hip and knee osteoarthritis (OA) are rising in prevalence and increasingly affecting younger patients. There is a rising demand for therapeutics to address its growing disease burden. Platelet-rich plasma (PRP) therapy has been used to treat various musculoskeletal conditions, but its role in OA treatment is not well understood. Even still, there is significant interest in this biologic for treatment of OA. The purpose of this study was to determine the PRP utilization trends in the United States for hip and knee OA.

METHODS

This was a retrospective review from the PearlDiver Patient Record Database. International Classification of Diseases and Current Procedural Terminology codes were used to identify patients who had received PRP injections for hip and knee OA from 2010 to 2018. Injection incidence was evaluated on an annual basis and by patient demographics, geographic distribution, and medical specialty under which the treatment was administered.

RESULTS

A total of 3,884 PRP injections were administered over the study period, 15% for hip OA and 85% for knee OA. PRP injections per 100,000 patient cases increased by an average year-over-year percentage of 53% and 12% for hip and knee OA, respectively. The highest injection incidences were observed in patients younger than 44 years of age. 58% of both hip and knee PRP injections were administered in general orthopaedic practices.

CONCLUSION

These findings show that PRP is increasingly being used as a treatment modality for hip and knee OA. There is a need for further research on its long term outcomes.

Efficacy and safety of platelet-rich plasma combined with hyaluronic acid versus platelet-rich plasma alone for knee osteoarthritis: a systematic review and meta-analysis

Purpose

To systematically evaluate the curative efficacy and safety of platelet-rich plasma (PRP) combined with hyaluronic acid (HA) in the treatment of knee osteoarthritis (KOA), comparing with platelet-rich plasma alone.

Methods

Cochrane Library, PubMed, China National Knowledge Infrastructure (CNKI) and Embase were searched for randomized controlled trials (RCTs) and cohort studies regarding the efficacy and safety of platelet-rich plasma (PRP) combined with hyaluronic acid (HA) in the treatment of knee osteoarthritis (KOA) comparing with platelet-rich plasma alone before January 15, 2022. The methodological quality of the ultimately included studies was assessed comprehensively, and meta-analysis was implemented using RevMan 5.3 software.

Results

Thirteen articles (9 RCTs, 4 cohort studies), including 1118 patients, were covered. There was no significant difference between the PRP + HA therapy and PRP-alone therapy in VAS scores at 3 months, 6 months and 12 months, WOMAC total scores at 3 months and KOOS at 1 month and 6 months. Compared with PRP-alone therapy, PRP + HA therapy was associated with significantly better improvement in VAS scores at 1 month, WOMAC total scores at 6 months, KOOS at 3 months, IKDC scores at 6 months and Lequesne index scores at 3 and 6 months. However, the smallest treatment effect of VAS scores, WOMAC total scores, KOOS and IKDC scores did not exceed the minimum clinically important difference (MCID). However, PRP + HA therapy got a greater reduction in the rate of adverse events, compared with PRP-alone therapy.

Conclusion

The results of this meta-analysis indicated that PRP + HA therapy was not found to be superior to PRP-alone therapy in pain relief and function improvement for patients with KOA. However, combined PRP with HA injections was generally safer than PRP injections alone, by assessing the incidence of adverse events.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03398-6.

Biologic principles of minced cartilage implantation: a narrative review

Cartilage tissue has a very limited ability to regenerate. Symptomatic cartilage lesions are currently treated by various cartilage repair techniques. Multiple treatment techniques have been proposed in the last 30 years. Nevertheless, no single technique is accepted as a gold standard. Minced cartilage implantation is a newer technique that has garnered increasing attention. This procedure is attractive because it is autologous, can be performed in a single surgery, and is therefore given it is cost-effective. This narrative review provides an overview of the biological potential of current cartilage regenerative repair techniques with a focus on the translational evidence of minced cartilage implantation.

The Efficacy of Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis Symptoms and Structural Changes: A Systematic Review and Meta-Analysis

BACKGROUND

Platelet-rich plasma (PRP) usage in orthopedics continues to rise, despite guidelines suggesting non-superiority to comparative cohorts. Therefore, we performed a systematic review and meta-analysis on PRP efficacy using two clinical assessments: (1) Visual Analog Scale and (2) Western Ontario and McMaster Universities Osteoarthritis Index. We assessed consistency and clinical relevancy by determining study heterogeneity (eg, sample sizes, ages, body mass index, arthritic severities, etc.). Comparative cohorts were: (A) hyaluronic acid (HA); (B) corticosteroid (CS); (C) normal saline (NS); and (D) exercise therapy. We performed sub-analyses of structural changes assessed on ultrasound, radiograph, or magnetic resonance imaging .

METHODS

We utilized PubMed, Cochrane Library, and Embase databases up to December 1, 2021, according to Preferred Reporting Items for Systematic-Reviews and Meta-Analyses guidelines. Twenty-four studies met criteria, with comparisons to: HA (n = 11); CS (n = 6); NS (n = 5); and exercise therapy (n = 3). Seven studies assessed structural changes. Evaluations utilized a methodological scoring system. I² statistics and forest plots pooled analyses and delineated study results.

RESULTS

PRP led to Visual Analog Scale and Western Ontario and McMaster Universities Osteoarthritis Index improvements in most studies when compared to HA, CS, and NS (P ≤ .05). Comparison to exercise therapy resulted in inconclusive findings (P ≥ .05). However, substantial heterogeneity (I² ≥ 76%) was reported due to study variability. No differences were found when assessing structural changes or cartilage thickness by magnetic resonance imaging (standardized mean difference -0.01 [-0.19, 0.18], P = .91).

CONCLUSIONS

PRP may be associated with pain and functional improvements but was not clinically relevant (inconsistent study- and patient-metrics). In addition, PRP did not confer superiority when assessing knee-related structural changes.

Owner assessed outcomes following elbow arthroscopy with or without platelet rich plasma for fragmented medial coronoid process

Objective

Document the outcomes of bilateral arthroscopic subtotal coronoidectomy for the fragmented medial coronoid process, quantify persistent lameness that required additional treatment (PRP), and document the outcomes of dogs that followed up with PRP injections.

Study design

Retrospective study.

Sample population

Overall, 115 dogs underwent arthroscopy alone and 31 received PRP at least 6 weeks after arthroscopy. The owner's response rate was ~50% (73 dogs).

Methods

Collected data included signalment, unilateral or bilateral clinical signs, intra-articular chondroprotective injection during the procedure, if PRP intra-articular injection was received postoperatively, and if it was received, the time from the initial surgery to administration was recorded. Outcomes were assessed via standardized owner questionnaires using the Liverpool Osteoarthritis in Dogs (LOAD) score, the Canine Brief Pain Inventory (CBPI) score, and the overall quality of life (QOL) assessment.

Results

Approximately 20% of the patients received PRP post-operatively due to persistent lameness following surgery. Similar pain scores were found between the two groups with an average of 11–13 LOAD score, 13–15 CBPI score, and good quality of life. Older animals at the time of surgery and those that received pain-relieving medications after the procedure were more painful and affected their functional outcome. PRP as an adjunctive therapy achieved a perceived good to excellent quality of life in ~90% of pets in this population.

Conclusion

Arthroscopy and subtotal coronoidectomy followed by PRP, if needed, seemed to decrease pain, and improve lameness in the long term.

Clinical significance

PRP should be considered as adjunctive therapy in dogs with the limited response to arthroscopy alone.

VEGF-attenuated platelet-rich plasma improves therapeutic effect on cartilage repair

Autologous platelet-rich plasma (PRP) has gained popularity as a less invasive treatment for various musculoskeletal tissue injuries and conditions due to its favorable safety profile, minimal manipulation and cost-effectiveness. Although PRP treatment has been clinically used for the treatment of osteoarthritis (OA) and damaged cartilage, evidence on therapeutic efficacy has been inconsistent, which calls for a methodology to achieve consistent and improved treatment outcomes. Given that PRP contains numerous proteins, we hypothesized that attenuation of a growth factor known to be detrimental to the healing tissue would enhance efficacy of PRP treatment. Considering that VEGF-mediated angiogenesis inhibits the repair of articular cartilage, we developed VEGF-attenuated PRP by sequestering VEGF in PRP using VEGF-binding microspheres. We demonstrated that VEGF attenuation in PRP did not inhibit the effect of PRP on chondrogenic differentiation of stem cells in vitro. In addition, healing of rat OA cartilage was significantly improved after treatment with VEGF-attenuated PRP when compared to the PRP treatment group or PBS control group. We expect that attenuation of unwanted biological activity using growth factor-binding microspheres could provide a new PRP customization method broadly applicable to various tissue repair processes.

Single intra-articular injection with or without intra-osseous injections of platelet-rich plasma in the treatment of osteoarthritis knee: A single-blind, randomized clinical trial

BACKGROUND

Subchondral bony structure damage plays an essential role in the pathogenesis of osteoarthritis (OA) knee. An intra-articular injection cannot reach the damaged subchondral bony structure and treat its pathologies effectively. The objective of the study was to compare the clinical effects of single intra-articular injection with or without intra-osseous injections of PRP in the treatment of osteoarthritis (OA) knee.

METHODS

This was a single-blind, parallel-group, randomized clinical trial. Fifty patients, with OA knee (K&L grade III), with ages between 50 and 65 years, were randomly allocated into 'intra-osseous, intra-articular PRP' ('IO+IA-PRP') (n = 25) or 'intra-articular PRP' group ('IA-PRP') (n = 25). Patients in the 'IO+IA-PRP' group received 18 ml PRP injection, and the 'IA-PRP' group received 8 ml PRP injection. Intra-osseous injections were given at the tibial plateau (5 ml) and femoral condyle (5 ml), along with intra-articular knee injection (8 ml), under fluoroscopic guidance. Outcomes were measured using VAS-pain, the knee injury and osteoarthritis outcome score (KOOS), and the treatment satisfaction scale. All patients (n = 50) were followed up till six months.

RESULTS

The mean age was 57.12(4.27) years and 57.00(4.96) years in the 'IO+IA-PRP' and 'IA-PRP' groups. Both groups showed significant improvement in pain relief (VAS pain) and KOOS parameters: pain, symptoms, ADL function, sport and recreation function, and quality of life. Compared to the 'IA-PRP' group, the 'IO+IA-PRP' group showed a greater reduction of VAS pain at six months. However, no significant difference was obtained in VAS pain-relief between these two groups (p = 0.422) at six months. Similarly, at 6 months, in inter-group comparison, except 'sport and recreation function' (p < 0.05), no significant differences were obtained in mean-scores of KOOS parameters: pain (p = 0.514); symptom (p = 0.148), ADL-function (p = 0.991), QoL-(p = 0.376). Patients in the 'IO+IA-PRP' group complained of significant 'injection-associated' adverse events and consumed a greater number of Acetaphenomen.

CONCLUSIONS

Both groups showed significant improvement following the intervention. Intra-osseous PRP injections did not provide any additional benefit over intra-articular PRP injection until six months regarding pain relief and functional improvement.

Intra-articular Pure Platelet-Rich Plasma Combined With Open-Wedge High Tibial Osteotomy Improves Clinical Outcomes and Minimal Joint Space Width Compared With High Tibial Osteotomy Alone in Knee Osteoarthritis: A Prospective Study

PURPOSE

To compare the clinical efficacy of the patients with medial compartment knee osteoarthritis who underwent either opening-wedge high tibial osteotomy alone (HTO) or simultaneous HTO and pure platelet-rich plasma therapy (HTO+P-PRP).

METHODS

Eighty patients were divided into 2 groups randomly, the HTO-alone group (n = 41) and the HTO+P-PRP group (n = 39). Patients were matched for preoperative age, sex, and body mass index. The outcomes studied included visual analogue scale (VAS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Lysholm score. The minimum width of medial knee joint (MJSW), medial proximal tibial angle (MPTA), femoral tibial angle (FTA), and weightbearing line (WBL) were measured preoperatively, immediately postoperatively, and 1, 6, 12, and 24 months postoperatively. Paired t test and chi-squared test were used for statistical analysis.

RESULTS

All patients were followed up at 1, 6, 12, and 24 months postoperatively. At 1, 6, and 12 months, pain and function scores in the HTO+P-PRP group were better than those in the HTO-alone group, especially at 6 months in Lysholm score (HTO alone, 72.5 ± 10.6; HTO+P-PRP, 83.1 ± 14.7; P = .003, 95% CI -14.13 to -10.42) and WOMAC (HTO alone, 90.3 ± 11.9; HTO+P-PRP, 75.6 ± 15.4; P < .001, 95% CI 13.36 to 20.11). For both groups, no difference was found preoperatively (HTO alone, varus 3.5 ± 3.9; HTO+P-PRP, varus 4.1 ± 4.0; P = .898) or postoperatively (HTO alone, valgus 6.7 ± 4.5; HTO+P-PRP, valgus 7.7 ± 2.3; P = .768) in FTA or WBL. The increase of the MJSW in the HTO+P-PRP group was significantly greater than that in the HTO-alone group during the first year, especially at 6 months (HTO alone, 3.8 ± 1.2 mm; HTO+P-PRP, 4.6 ± 1.1 mm; P = .001, 95% CI -1.27 to -0.35).

CONCLUSIONS

Compared with HTO alone, HTO combined with intra-articular P-PRP improved the minimum medial knee joint space width during the first year postoperatively. Clinically, a higher proportion of patients in the HTO+P-PRP group exceeded the minimal clinically important difference (MCID) in the first year, especially at 6 months in Lysholm score (HTO alone, 65.9%; HTO+P-PRP, 97.4%) and WOMAC (HTO alone, 82.9%; HTO+P-PRP, 100.0%).

LEVEL OF EVIDENCE

2, prospective comparative study.

Platelet-rich plasma outcomes do not correlate with patient satisfaction or perceived cost-effectiveness

BACKGROUND

As platelet-rich plasma injection for knee osteoarthritis (OA) has increased in popularity, it has become more important to assess its effectiveness and satisfaction with its use in the context of its high cost. The purpose of this study was to determine satisfaction, commercial appeal, and effectiveness of platelet-rich plasma (PRP) for the treatment of knee OA.

METHODS

A retrospective review of patients who underwent PRP injection in the knee from 2016 to 2019 was performed. Various patient-reported outcomes were collected, including: satisfaction with the PRP injection (out of 100), whether the patient would want to undergo PRP injection again, whether they would recommend the injection and whether they felt that the injection was worth the cost was collected. VAS pain scores were collected and measured out of 100. Demographics and radiographical information were obtained via chart review. Statistical analyses were conducted including descriptive statistics and binary logistic and linear regressions.

RESULTS

Overall, 114 patients were included. The mean pre-injectionpain score was 70.4, and the mean pain level decreased after injection to 36.8. Patients rated their satisfaction on average as neutral along the aforementioned continuous scale (49.2), , 50.9% stated that they would get the PRP injection again, 60.5% would recommend to a friend, and 50.9% felt the injection was worth the cost. Younger age and improved post-injection pain correlated with increasing likelihood of desiring further PRP injection.

CONCLUSIONS

Patients on average rated satisfaction slightly below average, indicating net neutrality in terms of satisfaction with their injection. Furthermore, only half of the patients indicated that it was worth the cost and that they would receive it again. Younger age and post-injection pain relief increased desire for further injection, but pain-relief did not correlate with patients saying that the injection was worth the cost.

Strategies for Articular Cartilage Repair and Regeneration

Articular cartilage is an avascular tissue, with limited ability to repair and self-renew. Defects in articular cartilage can induce debilitating degenerative joint diseases such as osteoarthritis. Currently, clinical treatments have limited ability to repair, for they often result in the formation of mechanically inferior cartilage. In this review, we discuss the factors that affect cartilage homeostasis and function, and describe the emerging regenerative approaches that are informing the future treatment options.

Using Platelet-Rich Plasma Hydrogel to Deliver Mesenchymal Stem Cells into Three-Dimensional PLGA Scaffold for Cartilage Tissue Engineering

The synthetic biodegradable polyester-based rigid porous scaffolds and cell-laden hydrogels have been separately employed as therapeutic modality for cartilage repair. However, the synthetic rigid scaffolds alone may be limited due to the inherent lack of bioactivity for cartilage regeneration, while the hydrogels have insufficient mechanical properties that are not ideal for load-bearing cartilage applications. In the present study, a hybrid construct was designed to merge the advantage of 3D-printed rigid poly(lactic-co-glycolic acid) (PLGA) scaffolds with cell-laden platelet-rich plasma (PRP) hydrogels that can release growth factors to regulate the tissue healing process. PRP hydrogels potentially achieved the effective delivery of mesenchymal stem cells (MSCs) into PLGA scaffolds. This hybrid construct could obtain adequate mechanical properties and independently provide MSCs with appropriate clues for proliferation and differentiation. Real-time gene expression analysis showed that PRP stimulated both chondrogenic and osteogenic differentiation of MSC seeding into PLGA scaffolds. Finally, the hybrid constructs were implanted into rabbits to simultaneously regenerate both articular cartilage and subchondral bone within osteochondral defects. Our findings suggest that this unique hybrid system could be practically applied for osteochondral regeneration due to its capacity for cell transportation, growth factors release, and excellent mechanical strength, which would greatly contribute to the progress of cartilage tissue engineering.

3D-Printed Reinforcement Scaffolds with Targeted Biodegradation Properties for the Tissue Engineering of Articular Cartilage

Achieving regeneration of articular cartilage is challenging due to the low healing capacity of the tissue. Appropriate selection of cell source, hydrogel, and scaffold materials are critical to obtain good integration and long-term stability of implants in native tissues. Specifically, biomechanical stability and in vivo integration can be improved if the rate of degradation of the scaffold material matches the stiffening of the sample by extracellular matrix secretion of the encapsulated cells. To this end, a novel 3D-printed lactide copolymer is presented as a reinforcement scaffold for an enzymatically crosslinked hyaluronic acid hydrogel. In this system, the biodegradable properties of the reinforced scaffold are matched to the matrix deposition of articular chondrocytes embedded in the hydrogel. The lactide reinforcement provides stability to the soft hydrogel in the early stages, allowing the composite to be directly implanted in vivo with no need for a preculture period. Compared to pure cellular hydrogels, maturation and matrix secretion remain unaffected by the reinforced scaffold. Furthermore, excellent biocompatibility and production of glycosaminoglycans and collagens are observed at all timepoints. Finally, in vivo subcutaneous implantation in nude mice shows cartilage-like tissue maturation, indicating the possibility for the use of these composite materials in one-step surgical procedures.

Treating Full Depth Cartilage Defects with Intraosseous Infiltration of Plasma Rich in Growth Factors: An Experimental Study in Rabbits

OBJECTIVE

Intraarticular (IA) administration of platelet-rich plasma (PRP) has been proposed as a new strategy to halt osteoarthritis (OA) progression. In patients with severe OA, its potential is limited because it is unable to reach the subchondral bone, so a new strategy is needed, and intraosseous (IO) infiltration has been suggested. The purpose is to assess the impact of IA together with IO infiltration of plasma rich in growth factors (PRGF) in serum hyaluronic acid (HA) and type II collagen cleavage neoepitope (C2C) levels.

DESIGN

A total of 32 rabbits were included in the study and randomly divided into 2 groups: control and treatment. A 4-mm chondral defect was created in the medial femoral condyle and IA followed by IO infiltration were performed. Serum C2C and HA levels were measured using enzyme-linked immunosorbent assay (ELISA) tests before infiltration and 28, 56, and 84 days post-infiltration.

RESULTS

Significant lower C2C serum levels were obtained in treatment group (IA + IO infiltration of PRGF) at 84 days post-infiltration than in control group (IA infiltration of PRGF + IO infiltration of saline solution), while no significant differences between groups were reported at any other study times. Regarding HA, at 56 days post-infiltration, greater significant levels were seen in the treatment group. However, at 84 days post-infiltration, no significant differences were obtained, although lower levels were reported in the treatment group.

CONCLUSIONS

Despite inconclusive, the results suggest that the combination of IA and IO infiltration with PRGF may enhance cartilage and subchondral bone regeneration, but further studies are needed.

Comparing the efficacy of dual Platelet-Rich Plasma (PRP) and Hyaluronic Acid (HA) therapy with PRP-alone therapy in the treatment of knee osteoarthritis: a systematic review and meta-analysis

Purpose

This study aims to compare the efficacy of a dual therapy of Platelet-Rich Plasma (PRP) and Hyaluronic Acid (HA) compared with PRP-alone therapy in the treatment of knee osteoarthritis (KOA).

Methods

PubMed, Embase, CINAHL, SCOPUS, Cochrane Library, grey literature and bibliographic references were searched from inception to January 2021. Only randomized controlled trials (RCTs) and retrospective cohort studies comparing the effect of PRP and HA versus PRP-alone therapy for KOA were included. Literature retrieval and data extraction were conducted by three independent reviewers. Pooled analysis of Visual Analogue Scale (VAS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), International Knee Documentation Committee (IKDC) scores and adverse events were conducted.

Results

Ten studies (7 RCTs, 3 cohort studies) involving 983 patients were covered. Dual PRP and HA therapy resulted in significant reduction in VAS compared to PRP-alone therapy at 4–6 weeks (P < 0.00001) and 12 months (P < 0.00001). Dual therapy resulted in better WOMAC score improvement at 3 (P = 0.02), 6 (P = 0.05) and 12 months (P < 0.0001) compared to PRP-alone therapy. The IKDC score for dual therapy was also higher at 6 months compared to PRP-alone therapy (P = 0.007). Regarding adverse events, dual therapy was generally safer than PRP-alone therapy (P = 0.02).

Conclusion

While there is a paucity of large high-quality Level I studies, current best evidence suggests that dual therapy with PRP and HA for KOA may be effective at providing pain relief and improvement in function up to 1 year following administration.

Level of evidence

II.

TNF-α Carried by Plasma Extracellular Vesicles Predicts Knee Osteoarthritis Progression

Objectives

To identify plasma extracellular vesicles (EVs) associated with radiographic knee osteoarthritis (OA) progression.

Methods

EVs of small (SEV), medium (MEV) and large (LEV) sizes from plasma of OA participants (n=30) and healthy controls (HCs, n=22) were profiled for surface markers and cytokine cargo by high-resolution flow cytometry. The concentrations of cytokines within (endo-) and outside (exo-) EVs were quantified by multiplex ELISA. EV associations with knee radiographic OA (rOA) progression were assessed by multivariable linear regression (adjusted for baseline clinical variables of age, gender, BMI and OA severity) and receiver operating characteristic (ROC) curve analysis.

Results

Based on integrated mean fluorescence intensity (iMFI), baseline plasma MEVs carrying CD56 (corresponding to natural killer cells) predicted rOA progression with highest area under the ROC curve (AUC) 0.714 among surface markers. Baseline iMFI of TNF-α in LEVs, MEVs and SEVs, and the total endo-EV TNF-α concentration, predicted rOA progression with AUCs 0.688, 0.821, 0.821, 0.665, respectively. In contrast, baseline plasma exo-EV TNF-α (the concentration in the same unit of plasma after EV depletion) did not predict rOA progression (AUC 0.478). Baseline endo-EV IFN-γ and exo-EV IL-6 concentrations were also associated with rOA progression, but had low discriminant capacity (AUCs 0.558 and 0.518, respectively).

Conclusions

Plasma EVs carry pro-inflammatory cargo that predict risk of knee rOA progression. These findings suggest that EV-associated TNF-α may be pathogenic in OA. The sequestration of pathogenic TNF-α within EVs may provide an explanation for the lack of success of systemic TNF-α inhibitors in OA trials to date.

Hesperidin mitigates inflammation and modulates ectoenzymes activity and some cellular processes in complete Freund's adjuvant-induced arthritic rats

OBJECTIVES

This study was aimed at assessing the anti-arthritic effects of hesperidin on the inflammatory markers in serum/plasma, ectoenzymes activity in platelet, reactive oxygen species (ROS), apoptosis and cell cycle in bone marrow cells of a rat model of arthritis.

METHODS

Fifty-six adult female Wistar rats (245-274 g) were grouped into eight of seven rats each: control rats given normal saline or 40 mg/kg of hesperidin or 80 mg/kg of hesperidin, 0.2 mg/kg of dexamethasone, arthritic rats given normal saline, or 40 mg/kg of hesperidin or 80 mg/kg of hesperidin, and 0.2 mg/kg of dexamethasone. Myeloperoxidase and nitrate plus nitrite levels were evaluated in the plasma and serum, respectively. The ecto-nucleoside triphosphate diphosphohydrolases, ecto-5'-nucleotidase and ecto-adenosine deaminase activities were assessed in platelets. Subsequently, the cells of the bone marrow were obtained, and the assays for ROS, apoptosis and cell cycle were evaluated using flow cytometry.

KEY FINDINGS

The results showed that hesperidin mitigated inflammation, modulated adenosine nucleotides and nucleoside hydrolysing enzymes and levels, minimized ROS intracellularly, attenuated apoptotic process and activated cell cycle arrest in arthritic rat.

CONCLUSION

This study suggests that hesperidin could be a natural and promising anti-inflammatory compound for the management of arthritis.

The Effect of a Single Freeze-Thaw Cycle on Matrix Metalloproteinases in Different Human Platelet-Rich Plasma Formulations

Storing platelet-rich plasma (PRP) for future use is a compelling approach, presuming the retention of biological properties is maintained. However, certain factors in PRP preparations have deleterious effects for the treatment of certain musculoskeletal conditions. The purpose of this study was to measure and compare matrix metalloproteinase protein (MMP) concentrations between fresh and freeze-thawed leukocyte-rich PRP (LR-PRP) inactivated (LR-I) and activated (LR-A) preparations, and leukocyte-poor PRP (LP-PRP) inactivated (LP-I) and activated (LP-A) preparations. A volume of 60 mL of whole blood was drawn from 19 healthy donors. LP-I and LR-I samples were processed using a manual extraction and centrifugation methodology. LP-A and LR-A products were activated with 10% CaCl2 and recombinant thrombin. Blood fractions were either immediately assayed and analyzed or stored at -80 °C for 24, 72 and 160 h. Multiplex immunoassay was used to measure MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, and MMP-12. MMP-1 concentrations increased in LR-A (p < 0.05) and MMP-9 significantly increased in LR-I (p < 0.05), while MMP-2 significantly decreased in LR-I (p < 0.05) and MMP-3 concentrations significantly decreased in LR-A (p < 0.05). MMP-12 concentrations also significantly decreased in LR-I (p < 0.05) from baseline concentrations. There were no significant differences between LP-A and LP-I preparations and MMP concentrations. MMP-10 concentrations in all PRP samples compared to each freezing time point were also not significantly different. MMPs regulate components of the extracellular matrix (ECM) in the remodeling phase of musculoskeletal injury. In this study, we observed a significant increase and decrease in MMP concentrations in response to a single freeze-thaw cycle in inactivated PRP and activated PRP preparations. This evidence contributes to the growing body of literature on the optimization of PRP preparation and storage strategies prior to delivery. Our findings suggest that specific PRP preparations after a single freeze-thaw may be more advantageous for certain musculoskeletal applications based on the presence of MMP concentrations.

Supercritical carbon dioxide decellularized porcine cartilage graft with PRP attenuated OA progression and regenerated articular cartilage in ACLT-induced OA rats

Knee osteoarthritis (OA) is a common degenerative articular disorder and considered one of the primary causes of pain and functional disability. Knee OA is prevalent in 10% of men and 13% of women aged 60 years above. The study aims to use cartilage tissue engineering that combines the triads of decellularized porcine cartilage graft as "scaffold," plasma rich platelet (PRP) as "signal" and chondrocytes from rat as "cell" to attenuate ACLT-induced OA progression and regenerate the knee cartilage in rats. Decellularization of the porcine cartilage was characterized by hematoxylin and eosin, 4,6-Diamidino-2-phenylindole staining, scanning electron microscopy and residual DNA quantification. The protective effect of decellularized porcine cartilage graft (dPCG) was evaluated by intra-articular administration in surgically induced anterior cruciate ligament transection (ACLT) rat osteoarthritis (OA) model. Supercritical carbon dioxide technology completely decellularized the porcine cartilage. Intra-articular administration of dPCG with or without PRP significantly reduced the ACLT-induced OA symptoms and attenuated the OA progression. Pain-relief by dPCG with or without PRP was assessed by capacitance meter and improved articular cartilage damage in the rat knee was characterized by X-ray and micro-CT. Besides, the histological analysis depicted cartilage protection by dPCG with or without PRP. The repairation and attenuation effect by dPCG with or without PRP in the articular knee cartilage damage were also explored by safranin-O, type II collagen, aggrecan and SOX-9 immuno-staining. To conclude, intra-articular administration of dPCG with or without PRP is efficient in repairing the damaged cartilage in the experimental OA model.

3D Printing of Collagen/Oligomeric Proanthocyanidin/Oxidized Hyaluronic Acid Composite Scaffolds for Articular Cartilage Repair

Articular cartilage defects affect millions of people worldwide, including children, adolescents, and adults. Progressive wear and tear of articular cartilage can lead to progressive tissue loss, further exposing the bony ends and leaving them unprotected, which may ultimately cause osteoarthritis (degenerative joint disease). Unlike other self-repairing tissues, cartilage has a low regenerative capacity; once injured, the cartilage is much more difficult to heal. Consequently, developing methods to repair this defect remains a challenge in clinical practice. In recent years, tissue engineering applications have employed the use of three-dimensional (3D) porous scaffolds for growing cells to regenerate damaged cartilage. However, these scaffolds are mainly chemically synthesized polymers or are crosslinked using organic solvents. Utilizing 3D printing technologies to prepare biodegradable natural composite scaffolds could replace chemically synthesized polymers with more natural polymers or low-toxicity crosslinkers. In this study, collagen/oligomeric proanthocyanidin/oxidized hyaluronic acid composite scaffolds showing high biocompatibility and excellent mechanical properties were prepared. The compressive strengths of the scaffolds were between 0.25–0.55 MPa. Cell viability of the 3D scaffolds reached up to 90%, which indicates that they are favorable surfaces for the deposition of apatite. An in vivo test was performed using the Sprague Dawley (SD) rat skull model. Histological images revealed signs of angiogenesis and new bone formation. Therefore, 3D collagen-based scaffolds can be used as potential candidates for articular cartilage repair.

Platelet-rich plasma inhibits Adriamycin-induced inflammation via blocking the NF-κB pathway in articular chondrocytes

Background

Previous studies showed that doxorubicin could lead to osteoarthritis (OA) by inducing chondrocyte inflammation and apoptosis. Besides, it is reported that platelet-rich plasma (PRP) could suppress the activation of inflammatory NF-κB signaling. Here, we aimed to determine whether PRP was able to exert a protective effect against doxorubicin-induced chondrocyte damages.

Methods

To determine whether PRP protects chondrocytes against destabilization of the medial meniscus (DMM)-induced osteoarthritis, mice were treated with PRP and doxorubicin, and the cartilage destruction was observed through Safranin O-fast green staining and osteoarthritis scoring. ELISA assay was used to check the release of TNF-α and ILs. In vitro, we treated chondrocytes with doxorubicin and PRP; CCK-8 was used to measure cell viability. Western blot, real-time PCR, and ELISA were applied to check apoptosis-related signaling and inflammation-associated factors.

Results

The results from the mouse model suggested that PRP attenuated doxorubicin-induced cartilage destruction in vivo. Doxorubicin promoted chondrocyte apoptosis while PRP ameliorated this damage. PRP inhibited doxorubicin-induced dysregulation of cell matrix-related factors, including SOX9, Col2A1, Col10A1, and Aggrecan, reduced protein levels of doxorubicin-induced inflammatory markers, COX-2, and iNOS, and blocked doxorubicin-induced phosphorylation of IκB and NF-κB in articular chondrocytes.

Conclusions

PRP improved doxorubicin-induced damage on chondrocytes. This research might provide a new theoretical basis for the clinical treatment of osteoarthritis caused by doxorubicin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00314-2.

Articular chondroprogenitors in platelet rich plasma for treatment of osteoarthritis and osteochondral defects in a rabbit knee model

BACKGROUND

Articular chondroprogenitors are a promising contender for cartilage repair due to their inherent nature which stands primed for chondrogenesis and minimal hypertrophic preponderance. Platelet rich plasma (PRP) has been extensively used for treating cartilage defects and osteoarthritis (OA), due to its chondro-inductive properties and abundant pool of growth factors. The aim of this study was to assess the efficacy of chondroprogenitors injected with PRP versus PRP alone in the healing of experimentally created early OA and osteochondral defects (OCD) in a rabbit model.

METHODS

Adult New Zealand White male rabbits were used for cell and PRP isolation. Chondroprogenitors were isolated by fibronectin adhesion assay, labelled with iron oxide, characterized for surface markers, differential potential and expanded. PRP was isolated by double spin centrifugation using a TriCell kit. Study groups included (a) Monosodium iodoacetate induced early OA and (b) critical OCD. Following intervention (test arm: PRP+ chondroprogenitors and control arm: PRP), assessment was performed at 6- and 12-weeks which included histopathological examination and scoring (OARSI and Modified Wakitani score), immunohistochemistry analysis (Collagen type II and X) and synovial fluid S100A12 levels.

RESULTS AND CONCLUSION

Comparable, evident healing was noticed in both test and control arms when the OA group samples were assessed at both time points. In the OCD group, PRP alone exhibited significantly better results than the test arm, although repair was notable in both interventions. Further evaluation of chondroprogenitors is required to assess their role as a standalone therapy and in combination with PRP to further cartilage regeneration.

Hyper-activated platelet lysates prevent glucocorticoid-associated femoral head necrosis by regulating autophagy

Platelet Rich Plasma (PRP) can activate angiogenic and osteogenic pathways, making it a highly promising therapeutic agent for bone growth. Super active platelet lysate (sPL) is derived from platelet-rich plasma (PRP) through ultra-low temperature freeze-thawing. The aim of this study was to evaluate the potential therapeutic effect of sPL on glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH). sPL increased the proliferation of GC-treated osteoblasts and endothelial cells, and inhibited apoptosis in vitro. Furthermore, sPL promoted healing of necrotic bone tissues in a rat ONFH model by restraining GC-induced apoptosis and increase autophagy of the osteoblasts. Overall, the results of this study provide a theoretical basis for the clinical application of sPL in ONFH.

The regenerative mechanisms of platelet-rich plasma: A review

Orthobiologics continue to gain popularity in many areas of medical science, especially in the field of regenerative medicine. Platelet-rich plasma derivatives are orthobiologic tools of particular interest. These biologic products can be obtained via centrifugation of a patient's whole blood and the components can then be subsequently isolated, concentrated and ultimately administered into injured tissues, particularly in areas where standard healing is disrupted. The elevated concentration of platelets above the basal value enables accelerated growth of various tissues with minimal side effects. The application of autologous orthobiologics is a relatively new biotechnology undergoing expansion which continues to reveal optimistic results in the stimulation and enhanced healing of various sorts of tissue injuries. The local release of growth factors and cytokines contained in platelet alpha granules accelerates and ameliorates tissue repair processes, mimicking and supporting standard wound healing. This effect is greatly enhanced upon combination with the fibrinolytic system, which are essential for complete regeneration. Fibrinolytic reactions can dictate proper cellular recruitment of certain cell populations such as mesenchymal stem cells and other immunomodulatory agents. Additionally, these reactions also control proteolytic activity in areas of wound healing and regenerative processes of mesodermal tissues including bone, cartilage, and muscle, which makes it particularly valuable for musculoskeletal health, for instance. Although many investigations have demonstrated significant results with platelet-rich plasma derivatives, further studies are still warranted.

A prepared platelet-rich plasma extract, namely Self-Growth Colony, inhibits melanogenesis by down-regulating microphthalmia-associated transcription factor in skin melanocyte

BACKGROUND

During melanogenesis, melanocytes produce melanin through enzymatic reactions. Microphthalmia-associated transcription factor (MITF) is a major regulator in controlling the expressions of melanogenic enzymes tyrosinase (TYR), tyrosine-related protein-1 (TRP1), and dopachrome tautomerase (DCT). Self-Growth Colony (SGC) is prepared from human platelet-rich plasma (PRP) having an enrichment of growth factors, and which has claimed skin regeneration function.

AIM

In this study, we aim to identify and investigate the novel role of SGC in skin melanogenesis.

METHODS

MTT assay was performed to determine the cytotoxicity of applied SGC. Melanin assay was adopted to quantify the intracellular melanin after SGC treatment. Promoter-driven luciferase assay, real-time PCR, and Western blotting were performed to determine the expressions of melanogenic enzymes and MITF in SGC-treated cultured Melan-A cells, being treated with or without UV induction. Ex vivo mouse skin was treated with SGC, and then was subjected to Western blotting and histochemical staining.

RESULTS

We identified that SGC inhibited melanogenesis in cultured melanocytes and ex vivo mouse skin. The phenomena were attributed to a reduction of MITF expression, which subsequently down-regulated the melanogenic enzymes, that is, TYR, TRP1, and DCT. Moreover, ERK signaling was activated in the SGC-inhibited melanogenesis.

CONCLUSIONS

The findings suggest that SGC extracting from human blood can be a safe and potential agent in promoting skin whitening.

A Retrospective Analysis of Characteristic Features of Responders and Impaired Patients to a Single Injection of Pure Platelet-Rich Plasma in Knee Osteoarthritis

(1) Background: The emergence of injectable “biologic” medication creates a new approach to treat osteoarthritis (OA). Among them, the use of intra-articular injection of PRP became widespread despite the absence of consensus regarding its optimal composition. The aim of this study was to retrospectively correlate an extensive biological characterization of injected PRP to the clinical responses of patients presenting knee OA. (2) Methods: This retrospective study included 75 patients with knee OA. Cartilage lesions were assessed using magnetic resonance imaging and the International Cartilage Regeneration Society (ICRS) classification. PRP extensive biological characterization was performed and patients’ subjective symptoms were recorded before injection and 3 and 6 months after injection using the Knee injury and Osteoarthritis Outcome Score (KOOS). Responders were defined by an improvement of 10 points on KOOS. (3) Results: At 6 months, 63.0% of the patients were responders. Impairment was characterized by a significantly higher proportion of patients with three compartments altered at baseline MRI and receiving a significantly higher dose of platelets compared to responders. (4) Conclusions: Single injection of pure PRP resulted in significant clinical improvement in the management of knee OA. Both baseline MRI and PRP biological features may be predictive factors of the clinical response, highlighting that a better understanding of action mechanism of PRP is still required.

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).

Platelet-Rich Plasma Versus Corticosteroids for the Treatment of Plantar Fasciitis: A Systematic Review and Meta-analysis

BACKGROUND

Plantar fasciitis is a common cause of heel pain. Corticosteroid injections are commonly used and proven to be effective, and lately platelet-rich plasma (PRP) has been used with mixed results.

PURPOSE

To perform a systematic review and meta-analysis comparing intralesional injections of PRP and steroid infiltration.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic review of Medline, Embase, Scopus, and Google Scholar including all level 1 and 2 studies from 2010 to 2019 was perfomed. American Orthopaedic Foot and Ankle Society and visual analog scale for pain scores were used as outcome variables. Publication bias and risk of bias was assessed with the Cochrane Collaboration tools. The Grading of Recommendations, Assessment, Development and Evaluations system was used to assess the quality of the body of evidence. Heterogeneity was assessed with χ² and I² statistics.

RESULTS

Fifteen studies were included in the analysis. Nine studies had a high risk of bias. There was 1 study with high quality, 9 with moderate, 2 studies with low, and 3 with very low quality. The pooled estimate for the American Orthopaedic Foot and Ankle Society score demonstrated nonsignificant differences at 1 month (P = .4) and 3 months (P = .076). At 6 months (P = .009) and 12 months (P = .009), it indicated significant differences in favor of PRP. The pooled estimate for visual analog scale demonstrated nonsignificant differences at 1 month (P = .653). At 3 months (P = .0001), 6 months (P = .002), and 12 months (P = .019), it yielded significant differences in favor of PRP.

CONCLUSION

The results of this systematic review and meta-analysis suggest that PRP is superior to corticosteroid injections for pain control at 3 months and lasts up to 1 year. In the short term, there is no advantage of corticosteroid infiltration. However, the low study quality, high risk of bias, and different protocols for PRP preparation reduce the internal and external validity of these findings, and these results must be viewed with caution.

In vitro characterisation of 3D printed platelet lysate-based bioink for potential application in skin tissue engineering

Wounds impact millions of patients every year and represent a serious cause of morbidity and mortality worldwide, yet current treatment outcomes are far from ideal. Therapies based on delivery of multiple growth factors offer a promising approach for optimal wound management; however, their high production cost, low stability, and lack of effective delivery system limits their application in the clinic. Platelet lysate is a suitable, abundant and cost-effective source of growth factors that play an important role in the healing cascade. The aim of this current work is to develop an extrusion-based bioink consisting of platelet lysate (PL) and gelatin methacryloyl (GelMA) (PLGMA) for the fabrication of a multifunctional 3D printed dermal equivalent. This bioink meets the essential requirements of printability in terms of rheological properties and shape fidelity. Moreover, its mechanical properties can be readily tuned to achieve stiffness that is equivalent to native skin tissue. Biologically relevant factors were successfully released in a sustainable manner for up to two weeks of study. The bioavailability of those factors was demonstrated by high cell viability, good cell attachment and improved proliferation of printed dermal fibroblasts. Furthermore, growth factors upregulated ECM synthesis and deposition by dermal fibroblasts after two weeks of culture.

Platelet-rich plasma-hyaluronic acid/chondrotin sulfate/carboxymethyl chitosan hydrogel for cartilage regeneration

In this study, the chondrogenic potential of hyaluronic acid/chondrotin sulfate/carboxymethyl chitosan hydrogels with adipose-derived mesenchymal stem cells (ADMSCs) was evaluated. Here, hyaluronic acid, chondrotin sulfate, and carboxymethyl chitosan were used as the substrate for cartilage tissue engineering in which the hydrogel is formed due to electrostatic and hydrogen bonds through mixing the polymers. Because of the instability of this hydrogel in the biological environment, 1-ethyl-3-(3-dimethylaminopropyl-carbodiimide hydrochloride/N-hydroxy-succinimide was used as a crosslinker to increase the hydrogel stability. The hydrogels showed reasonable stability due to the combined effect of self-crosslinking and chemical crosslinking. The cells were treated with the prepared hydrogel samples for 14 and 21 days in nondifferentiation medium for evaluation of the cellular behavior of ADMSCs. Gene expression evaluation was performed, and expression of specific genes involved in differentiation was shown in the crosslinked hydrogel with platelet-rich plasma (PRP) (H-EN-P) had increased the gene expression levels. Quantification of immunofluorescence intensity indicated the high level of expression of SOX9 in H-EN-P hydrogel. Based on the results, we confirmed that the presence of PRP and the similarity of the hydrogel constituents to the cartilage extracellular matrix could have positive effects on the differentiation of the cells, which is favorable for cartilage tissue engineering approaches.

Platelet-rich plasma (PRP) in osteoarthritis (OA) knee: Correct dose critical for long term clinical efficacy

Despite encouraging results reported with regards to Platelet-rich plasma (PRP) application in osteoarthritis (OA) knee, still critical issues like conclusive structural evidence of its efficacy, standard dose and good manual method of preparation to obtain high yield remains unanswered. Present study is an attempt to optimise the dose and concentration of therapeutic PRP and its correlation with structural, physiologic efficacy with a new manual method of PRP preparation. A total of one hundred and fifty patients were randomized to receive either PRP (10 billion platelets) or hyaluronic acid (HA; 4 ml; 75 patients in each group) and followed up till 1 year. An addition of filtration step with 1 µm filter in manual PRP processing improved platelet recovery upto 90%. Significant improvements in WOMAC (51.94 ± 7.35 vs. 57.33 ± 8.92; P < 0.001), IKDC scores (62.8 ± 6.24 vs 52.7 ± 6.39; P < 0.001), 6-min pain free walking distance (+ 120 vs. + 4; P < 0.001) persisted in PRP compared to HA group at 1 year. Significant decline IL-6 and TNF-α levels observed in PRP group (P < 0.05) compared to HA at 1 month. Study demonstrated that an absolute count of 10 billion platelets is crucial in a PRP formulation to have long sustained chondroprotective effect upto one year in moderate knee OA.

Low-fluence laser-facilitated platelet-rich plasma permeation for treating MRSA-infected wound and photoaging of the skin

Platelet-rich plasma (PRP) is rich in cytokines and growth factors and is a novel approach for tissue regeneration. It can be used for skin rejuvenation but the large molecular size of the actives limits its topical application. In this study, low-fluence laser-facilitated PRP was delivered to evaluate its effect on absorption through the skin, infection-induced wound, and photoaging. The PRP permeation enhancement was compared for two ablative lasers: fractional (CO₂) laser and fully-ablative (Er:YAG) laser. In the Franz cell experiment, pig skin was treated with lasers with superficial ablation followed by the application of recombinant cytokines, growth factors, or PRP. The transport of interferon (IFN)-γ and tumor necrosis factor (TNF)-α was negligible in intact skin and stratum corneum (SC)-stripped skin. Both lasers significantly elevated skin deposition of IFN-γ and TNF-α from PRP, and fully-ablative laser showed a higher penetration enhancement. A similar tendency was found for vascular endothelial growth factor and epidermal growth factor. Er:YAG laser-exposed skin displayed 1.8- and 3.9-fold higher skin deposition of platelet-derived growth factor (PDGF)-BB and transforming growth factor (TGF)-β1 from PRP, respectively. According to the confocal images, both laser interventions led to an extensive and deep distribution of IFN-γ and PDGF-BB in the skin. In the in vivo methicillin-resistant Staphylococcus aureus (MRSA) infection model, CO₂ laser- and Er:YAG laser-assisted PRP delivery reduced bacterial load from 1.8 × 10⁶ to 5.9 × 10⁵ and 1.4 × 10⁴ colony-forming units, respectively. The open wound induced by MRSA was closed by the laser-assisted PRP penetration. In the mouse photoaging model, elastin and collagen deposition were fully restored by combined PRP and full-ablative laser but not by PRP alone and PRP combined with fractional laser. Laser-facilitated PRP delivery even with a low fluence setting can be considered a promising strategy for treating some dermatological disorders.

Platelet-Rich Plasma Ameliorates Monosodium Iodoacetate-Induced Ankle Osteoarthritis in the Rat Model via Suppression of Inflammation and Oxidative Stress

Until now, there is no treatment that cause complete cure of the chronic inflammatory and degenerative disease, osteoarthritis (OA). Moreover, the underlying mechanisms of OA development and progress are not fully elucidated, and the present pharmacological treatment alternatives are restricted and associated with adverse side effects. Thus, the present study was conducted to evaluate the role of platelet-rich plasma (PRP) in the remedy of OA in the rat model in terms of inflammation, ankle histopathological alterations, and oxidative stress. OA was induced in male Wistar rats by injection of MIA (2 mg)/50 µL isotonic saline in the right ankle joint for two successive days in each rat. After the 2nd MIA injection, the osteoarthritic rats were allocated into two groups such as the MIA group (group 2) and MIA + PRP group (group 3). The MIA + PRP group was treated with PRP (50 µL) by injection into the ankle joint of the right hind limb of each rat at days 14, 21, and 28 after the 2nd injection of MIA. The same equivalent volume of saline, as a substitute of PRP, was injected into the ankle joint of each rat of the normal control group (group 1) and MIA group (group 2) at the same tested periods. Swelling of joint, bodyweight, total leucocytes count (TLC), and morphological as well as histological changes of ankle joints were evaluated. Serum lipid peroxides (LPO), glutathione (GSH), and glutathione S-transferase (GST) levels were examined as biomarkers of oxidative stress. Serum tumor necrosis factor-α (TNF-α), interleukin-17 (IL-17), and interleukin-4 (IL-4) were investigated by ELISA as biomarkers of inflammation. In addition, magnetic resonance imaging (MRI) was carried out to investigate the soft tissues in joints. The obtained results revealed that PRP reduced LPO and increased GSH and GST levels in osteoarthritic rats. Also, PRP significantly diminished serum TNF-α and IL-17 levels, while it increased IL-4 serum levels in rats with MIA-induced OA. Morphological observations, histological analysis, and MRI revealed a gradual diminishing in joint inflammation and destruction of cartilage in PRP-injected osteoarthritic rats. Based on these results, it can be suggested that PRP has antiarthritic potential in MIA-induced OA, which may be mediated via suppression of inflammation and oxidative stress.

Effects of platelet-rich plasma injection for pain control and cartilage repair in knee osteoarthritis: A protocol for the systematic review and meta-analysis of randomized controlled trials in animal models

BACKGROUND

Knee osteoarthritis (KOA) is a common disabling condition and a heavy financial burden to the society. Platelet-rich plasma (PRP) is considered to be an effective method in the repair and regeneration of cartilage and alleviate pain in KOA. But the utilising of PRP to treat KOA in clinical has shown variable results from many studies. The objective of this protocol is to determine the efficacy of PRP in pain control and cartilage repair in KOA animal models.

METHOD

We will search the following three electronic databases: MEDLINE, EMBASE and Web of Science. The primary outcome will include the histological score of cartilage and pain score. The secondary outcomes will be the behavioural assessments and cartilage thickness. SYRCLE's risk of bias tool will be used to assessment the risk of bias of including studies. The standardized mean difference and 95% confidence interval will be used to calculate the effect of PRP treatment. The I2 inconsistency values will be used to calculated the heterogeneity between studies.

RESULTS

The results of this paper will be submitted to a peer-reviewed journal for publication.

CONCLUSION

This research will determine the efficacy of PRP of the treatment of knee osteoarthritis model.

PROSPERO REGISTRATION NUMBER

CRD42020181589.

Chondrogenic differentiation of Wharton's Jelly mesenchymal stem cells on silk spidroin-fibroin mix scaffold supplemented with L-ascorbic acid and platelet rich plasma

In this research, hWJ-MSCs were grown on silk scaffolds and induced towards chondrogenesis by supplementation with L-ascorbic acid (LAA) or platelet rich plasma (PRP). Silk scaffolds were fabricated with salt leaching method by mixing silk fibroin (SF) with silk spidroin (SS). The silk fibroin was obtained from Bombyx mori cocoon that had been degummed, and the silk spidroin was obtained from wild-type spider Argiope appensa. The effect of scaffold composition and inducer on cell proliferation was observed through MTT assay. The most optimal treatment then continued to be used to induce hWJ-MSC towards chondrogenic differentiation for 7 and 21 days. Scaffolds characterization showed that the scaffolds produced had 3D structure with interconnected pores, and all were biocompatible with hWJ-MSCs. Scaffold with the addition of 10% SS + 90% SF showed higher compressive strength and better pore interconnectivity in comparison to 100% silk fibroin scaffold. After 48 h, cells seeded on scaffold with spidroin and fibroin mix had flattened morphology in comparison to silk fibroin scaffold which appeared to be more rounded on the scaffold surface. Scaffold with 10% (w/w) of silk spidroin (SS) + 90% (w/w) of silk fibroin (SF) was the most optimal composition for cell proliferation. Immunocytochemistry of integrin β1 and RGD sequence, showed that scaffold with SS 10% provide better cell attachment with the presence of RGD sequence from the spidroin silk which could explain the higher cell proliferation than SF100% scaffold. Based on Alcian Blue staining and Collagen Type II immunocytochemistry (ICC), cells grown on 10% SS + 90% SF scaffold with 10% PRP supplementation were the most optimal to support chondrogenesis of hWJ-MSCs. These results showed that the addition of spidroin silk from A. appensa. had impact on scaffold compressive strength and chondrogenic differentiation of hWJ-MSC and had the potential for further development of bio-based material scaffold in cartilage tissue engineering.