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

Platelet-rich plasma alleviates knee arthritis in rats by inhibiting p65

Knee osteoarthritis (KOA) is a chronic joint disease characterized by the degeneration of articular cartilage. In this study, we explored the potential therapeutic effects of platelet-rich plasma (PRP) and identified molecular targets for treating KOA. A rat model of KOA was established via the Hulth method and primary knee joint chondrocytes were isolated to evaluate the effects of PRP and shRNA targeting p65 (sh-p65). ELISA was used to detect inflammatory factors, including IL-6, IL-1β, and TNF-α. HE staining, Safranin O/Fast Green staining and Masson staining were performed to evaluate the morphology of articular cartilage, followed by detection of p65, COL2A1, ACAN, MMP13, and ADAMTS5 expression. The proliferation and apoptosis of primary knee chondrocytes were detected by the CCK-8 assay and TUNEL staining, respectively. Treatment with either PRP or sh-p65 decreased IL-6, IL-1β, and TNF-α levels in the peripheral blood of KOA rats and chondrocyte culture supernatants, increased COL2A1 and ACAN levels, and decreased MMP13 and ADAMTS5 expression. Furthermore, administration of PRP or sh-p65 exerted protective effects on articular cartilage, enhanced the vitality of knee joint chondrocytes, and inhibited apoptosis. Collectively, PRP inhibited inflammation, promoted chondrocyte proliferation and cartilage matrix secretion, and induced cartilage regeneration by suppressing p65 expression; these effects allow PRP to alleviate KOA progression. P65-based targeted therapy administered in combination with PRP might be a promising strategy for treating KOA.

Biochemical and biomechanical characterization of an autologous protein-based fibrin sealant for regenerative medicine

Accidental events or surgical procedures usually lead to tissue injury. Fibrin sealants have proven to optimize the healing process but have some drawbacks due to their allogeneic nature. Autologous fibrin sealants present several advantages. The aim of this study is to evaluate the performance of a new autologous fibrin sealant based on Endoret®PRGF® technology (E-sealant). One of the most widely used commercial fibrin sealants (Tisseel®) was included as comparative Control. E-sealant´s hematological and biological properties were characterized. The coagulation kinetics and the microstructure were compared. Their rheological profile and biomechanical behavior were also recorded. Finally, the swelling/shrinkage capacity and the enzymatic degradation of adhesives were determined. E-sealant presented a moderate platelet concentration and physiological levels of fibrinogen and thrombin. It clotted 30 s after activation. The microstructure of E-sealant showed a homogeneous fibrillar scaffold with numerous and scattered platelet aggregates. In contrast, Control presented absence of blood cells and amorphous protein deposits. Although in different order of magnitude, both adhesives had similar rheological profiles and viscoelasticity. Control showed a higher hardness but both adhesives presented a pseudoplastic hydrogel nature with a shear thinning behavior. Regarding their adhesiveness, E-sealant presented a higher tensile strength before cohesive failure but their elastic stretching capacity and maximum elongation was similar. While E-sealant presented a significant shrinkage process, Control showed a slight swelling over time. In addition, E-sealant presented a high enzymatic resorption rate, while Control showed to withstand the biodegradation process in a significant way. E-sealant presents optimal biochemical and biomechanical properties suitable for its use as a fibrin sealant with regenerative purposes.

The Combined Intraosseous Administration of Orthobiologics Outperformed Isolated Intra-articular Injections in Alleviating Pain and Cartilage Degeneration in a Rat Model of MIA-Induced Knee Osteoarthritis

BACKGROUND

Intra-articular (IA) platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) injections have shown efficacy and safety in treating osteoarthritis (OA). However, the effectiveness and mechanisms of combined intraosseous (IO) administration of these orthobiologics have yet to be explored.

PURPOSE/HYPOTHESIS

The purpose of this study was to evaluate the effect on pain, cartilage, synovium/infrapatellar fat pad (IFP), and subchondral bone in rat knee OA, comparing isolated IA with combined IA and IO (IA+IO) injections of PRP or BMAC. It was hypothesized that combined injections would be superior to sole IA injections.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 48 rats were divided into 6 groups: sham (only joint puncture during OA induction with IA+IO saline injection treatment) and 5 groups with OA induction, control (IA+IO saline injection), PRP (IA PRP+IO saline injection), BMAC IA (IA BMAC+IO saline injection), PRP IA+IO (IA+IO PRP injection), and BMAC IA+IO (IA+IO BMAC injection). OA was induced by IA injection of monosodium iodoacetate (MIA). Rats were administered different orthobiologics according to their grouping 3 weeks after the MIA injection. Pain changes were evaluated using the weightbearing ratio assay at weeks 3, 4, 5, 7, and 9 after OA induction. Rats were euthanized at week 9 for gross, radiological, histological, immunohistochemical, and immunofluorescence assessments of cartilage, synovium, and subchondral bone.

RESULTS

Compared with the control group, all orthobiologics injection groups had reduced joint pain. Compared with IA injection, IA+IO injections provided superior pain relief by suppressing calcitonin gene-related peptide and substance P in both the synovium/IFP and subchondral bone. IA+IO injections slowed the progression of subchondral bone lesions by inhibiting CD31hiEmcnhi vessel formation and excessive osteoclast and osteoblast turnover while preserving subchondral bone microarchitecture, slowing cartilage degeneration. However, IA+IO injections did not outperform isolated IA injections in reducing synovitis and synovium/IFP fibrosis. Compared with PRP, BMAC exhibited superior inhibition of pain-related mediators, but no significant differences were observed in synovitis suppression, infrapatellar fat pad fibrosis, and subchondral bone protection.

CONCLUSION

IA+IO injections of orthobiologics were more effective in relieving pain, slowing cartilage degeneration, and inhibiting abnormal vascularization and remodeling compared with isolated IA injections. BMAC showed superior pain relief in the synovium/IFP and subchondral bone compared with PRP. Further research is needed to optimize PRP and BMAC components for enhanced efficacy in OA management.

CLINICAL RELEVANCE

Our findings contribute to advancing the understanding of pain relief mechanisms and support the endorsement of IO injection of orthobiologics for the treatment of OA and joint pain.

Anti-Aging Potential of Platelet Rich Plasma (PRP): Evidence from Osteoarthritis (OA) and Applications in Senescence and Inflammaging

Aging and age-related changes impact the quality of life (QOL) in elderly with a decline in movement, cognitive abilities and increased vulnerability towards age-related diseases (ARDs). One of the key contributing factors is cellular senescence, which is triggered majorly by DNA damage response (DDR). Accumulated senescent cells (SCs) release senescence-associated secretory phenotype (SASP), which includes pro-inflammatory cytokines, matrix metalloproteinases (MMPs), lipids and chemokines that are detrimental to the surrounding tissues. Chronic low-grade inflammation in the elderly or inflammaging is also associated with cellular senescence and contributes to ARDs. The literature from the last decade has recorded the use of platelet rich plasma (PRP) to combat senescence and inflammation, alleviate pain as an analgesic, promote tissue regeneration and repair via angiogenesis-all of which are essential in anti-aging and tissue regeneration strategies. In the last few decades, platelet-rich plasma (PRP) has been used as an anti-aging treatment option for dermatological applications and with great interest in tissue regeneration for orthopaedic applications, especially in osteoarthritis (OA). In this exploration, we connect the intricate relationship between aging, ARDs, senescence and inflammation and delve into PRP's properties and potential benefits. We conduct a comparative review of the current literature on PRP treatment strategies, paying particular attention to the instances strongly linked to ARDs. Finally, upon careful consideration of this interconnected information in the context of aging, we suggest a prospective role for PRP in developing anti-aging therapeutic strategies.

Office-Based Intraosseous Infiltrations of PRGF as an Effective Treatment for Knee Osteoarthritis: A Retrospective Observational Clinical Study

The aim of this study was to explore and assess office-based ultrasound-guided intraosseous and intra-articular infiltrations of plasma rich in growth factors (PRGF) in patients with moderate and severe knee osteoarthritis (KOA). Seventy-nine patients (30 women and 49 men) with grade 3-4 KOA according to the Kellgren-Lawrence classification participated in the study. All patients were treated with a minimally invasive technique using local anesthesia WALANT (wide-awake local anesthesia no tourniquet) in the ambulatory setting. A PRGF intra-articular infiltration and two intraosseous infiltrations in the tibial plateau and femoral condyle were performed weekly for a total of three sessions. The evaluation of the results was carried out using knee injury and osteoarthritis outcome score (KOOS) at baseline and post-treatment. After a follow-up period of 11 months (median) [interquartile range, 7-14], all the KOOS domains showed statistically significant improvement (p < 0.001). Moreover, 88% of the patients showed a pain reduction of at least 10 points (minimally clinically important improvement) from pre- to post-treatment. Our retrospective study using the in-office procedure of ultrasound-guided combination of intra-articular and intraosseous infiltrations of PRGF is a safe and efficacious approach for the treatment of grade 3-4 knee osteoarthritis.

Platelet-Rich Plasma for Knee Osteoarthritis: What Does the Evidence Say?

The utilization of platelet-rich-plasma as a therapeutic intervention for knee osteoarthritis has gained immense attention since 2008. The increase in the number of scientific publications dedicated to this area can be attributed to the majority of favorable results reported in clinical trials and basic science studies. However, despite the growing evidence, the use of platelet-rich plasma in clinical practice still poses controversial aspects. The potential mechanisms of action described for platelet-rich-plasma so far indicate that it could serve as a disease-modifying drug, acting to counteract important aspects of knee osteoarthritis pathophysiology (cartilage breakdown, inflammation, and bone remodeling). Nevertheless, its efficacy in slowing down the progression of knee osteoarthritis remains unproven. While inconsistencies have been noted, the majority of controlled clinical trials and meta-analyses advocate for the utilization of platelet-rich-plasma in treating knee osteoarthritis, as it has demonstrated greater efficacy than hyaluronic acid and placebo, with a follow-up of at least 1 year. Despite advancements made in certain areas, significant diversity persists regarding the formulations used, therapeutic regimen, extended follow-up periods, patient selection, and assessment of clinically relevant outcomes. Consequently, the leading clinical practice guidelines do not recommend its use. In light of the emerging evidence, this narrative review aims to provide an objective evaluation of the recent available scientific literature (last 5 years) focused on randomized clinical trials and meta-analyses to present a current overview of the topic.

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.

Combined subchondral and intra-articular injections of bone marrow aspirate concentrate provide stable results up to 24 months

PURPOSE

The aim of this study was to evaluate the clinical and imaging findings up to 24 months of follow-up in patients treated with combined subchondral and intra-articular bone marrow aspirate concentrate (BMAC) injections for the treatment of knee osteoarthritis (OA).

METHODS

Thirty consecutive patients (19 males, 11 females) aged between 40 and 75 years (mean age 56.4 ± 8.1 years) with unilateral symptomatic knee OA (Kellgren-Lawrence 2-3) were included in the study. Patients were treated with combined intra-articular and subchondral bone BMAC injections (total 9 ml) under fluoroscopic control. IKDC subjective score, VAS for pain, KOOS, and EQ-VAS were prospectively evaluated up to 24 months. Radiographs were performed at baseline and at 24 months after the procedure. MRI was evaluated with the WORMS score at baseline, 6-12 months, and 24 months of follow-up. The statistical analysis was performed using SPSS v.19.0 and for all tests p < 0.05 was considered significant.

RESULTS

No major complications and a 13% failure rate were reported. The IKDC subjective score remained stable from 62.6 ± 19.4 at 12 months to 63.4 ± 17.1 at 24 months (both p < 0.0005 compared to baseline, 40.5 ± 12.5). Similar improvements were reported for all KOOS subscales, while EQ-VAS did not report any significant improvement. VAS pain worsened from 3.0 ± 1.9 at 12 months to 4.4 ± 1.8 at the final follow-up (p = 0.0001), although remaining lower compared to the baseline value of 6.3 ± 1.8 (p = 0.002). The radiographic evaluation did not reveal signs of improvement or deterioration of the OA grade. The MRI findings showed a worsening in marginal osteophytes and synovitis, but a significant reduction of bone marrow edema at 24 months (p < 0.0005).

CONCLUSION

Combined intra-articular and subchondral BMAC injections provided clinical and imaging benefits up to 24 months for the treatment of symptomatic knee OA, with durable clinical results, a low failure rate, and a significant reduction of bone marrow edema.

Intraosseous Infiltration of Platelet-Rich Plasma for Knee Osteoarthritis: A Systematic Review of Literature and Limited Meta-analysis

Background

The role of subchondral bone as a key mediator in pathogenesis of osteoarthritis (OA) is emerging and various injectable modalities are being tried to address the subchondral pathology. Intraosseous (IO) infiltrations of PRP is biological way of addressing the pathology. This review aimed to explore the role of IO PRP in OA knees.

Methods

A systematic literature search was conducted on the electronic databases of PubMed, Embase, Scopus, Web of Science and Ovid for relevant articles on IO PRP with a predefined search strategy. Data from eligible studies were extracted and was analyzed.

Results

There were only five studies on the study topic which included 112 patients (112 knees) who received IO PRP injection. IO PRP was associated with significant improvements in VAS, KOOS and WOMAC scores. The most commonly reported complication was pain at injection site. Meta-analysis revealed that combined intraarticular (IA) and IO PRP were associated with significantly better WOMAC scores, compared to only IA PRP. However, VAS and KOOS scores were equivocal.

Conclusion

IO PRP infiltration for OA knees is safe and effective and results in improved patient-reported outcome scores based on the current limited literature. However, its added advantage over only IA PRP is not well established and clear due to limited available published data.

Does Bone Marrow Edema Influence the Clinical Results of Intra-Articular Platelet-Rich Plasma Injections for Knee Osteoarthritis?

Platelet-rich plasma (PRP) is increasingly used for the intra-articular treatment of knee osteoarthritis (OA). However, clinical studies on PRP injections reported controversial results. Bone marrow edema (BME) can cause symptoms by affecting the subchondral bone and it is not targeted by intra-articular treatments. The aim of this study was to investigate if the presence of BME can influence the outcome of intra-articular PRP injections in knee OA patients. A total of 201 patients were included in the study, 80 with and 121 without BME at the baseline MRI. BME area and site were evaluated, and BME was graded using the Whole-Organ Magnetic Resonance Imaging Score (WORMS). Patients were assessed with International Knee Documentation Committee (IKDC) score Knee injury and Osteoarthritis Outcome Score (KOOS) subscales, the EuroQol-Visual Analogue Scale (EQ-VAS), and the Tegner score at baseline, 2, 6, and 12 months. Overall, the presence of BME did not influence the clinical results of intra-articular PRP injections in these patients treated for knee OA. Patients with BME presented a similar failure rate and clinical improvement after PRP treatment compared to patients without BME. The area and site of BME did not affect clinical outcomes. However, patients with a higher BME grade had a higher failure rate.

Effect of Combined Intraosseous and Intraarticular Infiltrations of Autologous Platelet-Rich Plasma on Subchondral Bone Marrow Mesenchymal Stromal Cells from Patients with Hip Osteoarthritis

Osteoarthritis (OA) is a debilitating condition that significantly impacts its patients and is closely associated with advancing age and senescence. Treatment with autologous platelet rich plasma (PRP) is a novel approach that is increasingly being researched for its effects. Subchondral bone mesenchymal stromal cells (MSCs) are key progenitors that form bone and cartilage lineages that are affected in OA. This study investigated the changes in subchondral bone MSCs before and after combined intraosseous (IO) and intraarticular (IA) PRP infiltration. Patient bone marrow aspirates were collected from 12 patients (four male, eight female) aged 40–86 years old (median 59.5). MSCs were expanded in standard media containing human serum to passage 1 and analysed for their colony-forming potential, senescence status, and gene expression. Hip dysfunction and Osteoarthritis Outcome Score (HOOS) at baseline and 6 months post second infiltration were used to assess the clinical outcomes; seven patients were considered responders and five non-responders. The number of colony-forming MSCs did not increase in the post treatment group, however, they demonstrated significantly higher colony areas (14.5% higher compared to Pre) indicative of enhanced proliferative capacity, especially in older donors (28.2% higher). Senescence assays also suggest that older patients and responders had a higher resistance to senescent cell accumulation. Responder and non-responder MSCs tended to differ in the expression of genes associated with bone formation and cartilage turnover including osteoblast markers, matrix metalloproteinases, and their inhibitors. Taken together, our data show that in hip OA patients, combined IO and IA PRP infiltrations enhanced subchondral MSC proliferative and stress-resistance capacities, particularly in older patients. Future investigation of the potential anti-ageing effect of PRP infiltrations and the use of next-generation sequencing would contribute towards better understanding of the molecular mechanisms associated with OA in MSCs.

Real-world evidence to assess the effectiveness of platelet-rich plasma in the treatment of knee degenerative pathology: a prospective observational study

Objective:

The present work aims to analyse the effectiveness of platelet-rich plasma (PRP) in degenerative knee pathology based on real-world data and to evaluate possible factors influencing the response to treatment.

Methods:

In total, 531 cases were analysed collecting data on gender, age, body mass index, pathology location, severity, number of cycles and route of administration. Clinical outcome was evaluated at 6 and 15 months after treatment, using the Knee injury and Osteoarthritis Outcome Score (KOOS) and obtaining percentages of Minimal Clinically Important Improvement (MCII). Blood and PRP samples were randomly tested as a quality control measure to ensure the correct properties. Comparative statistical tests and multivariate regression were performed for the analysis of the variables.

Results:

The PRP applied had a platelet concentration factor of 1.67, with no leukocytes or erythrocytes. The percentage of patients with MCII at 6 and 15 months after PRP application was 59.32% and 70.62%, respectively. Patients with MCII were younger (p = 0.0246) and with lower body mass index (p = 0.0450). The treatment had a better response in mild/moderate cases than in severe cases (p = 0.0002). Intraosseous PRP application in severe cases improved the effect of intraarticular PRP (p = 0.0358). The application of a second cycle of PRP only improved the response in patients without MCII at 6 months (p = 0.0029), especially in mild/moderate cases (p = 0.0357).

Conclusion:

The applications of PRP in degenerative knee pathologies is an effective treatment, but this effectiveness nonetheless depends on several variables. Real-world data can complement that from clinical trials to provide valuable information.

The aging athlete

Aging athletes, those 60 years and older, are a growing population of mature, active individuals who value sports and exercise participation throughout their lifespan. Although recommendations for younger and masters athletes have been extrapolated to this population, there remains a paucity of specific guidelines, treatment algorithms, and considerations for aging athletes. The benefits of living an active lifestyle must be weighed against the risks for unique cardiovascular, metabolic, and musculoskeletal injuries requiring diagnostic and therapeutic interventions. In this article, we review the unique cardiovascular and muscular physiology of aging athletes and how it influences the risk of specific medical conditions. We also discuss general prevention and treatment strategies. Finally, we identify areas of future research priorities and emerging treatments.

Office-Based Intraosseous Infiltrations of PRGF in Knee Osteoarthritis: Description of Technique

Knee osteoarthritis is a low-degree inflammatory condition that involves the whole synovial joint tissues as an organ. Recently, a biological approach using plasma rich in growth factors (PRGF) to tackle not only the synovial joint with intraarticular injections of PRGF, but also the subchondral bone with intraosseous infiltrations has been implemented with promising results. However, this procedure requires sedation, which limits the implementation of the procedure to operating room. We propose a modified and less cumbersome PRGF intraosseous infiltration approach for moderate and severe knee osteoarthritis, conducting the procedure in the ambulatory setting assisted with WALANT (wide-awake local anesthesia no tourniquet) technique. The proposed technique with a minimally invasive local anesthesia involves subcutaneous infiltration of lidocaine and epinephrine in a solution without sedation, and using ultrasound guidance, thereby streamlining the original procedure. This procedure is both a cost-effective and safe approach that may contribute to the widespread use of intraosseous infiltrations.

Subchondral versus intra-articular orthobiologic injections for the treatment of knee osteoarthritis: a review

Recent perspectives suggest that osteoarthritis (OA) is a disease involving not only the articular cartilage but also the osteochondral unit, including the synovium, supportive cartilage and subchondral bone. Current conservative treatments for OA are symptomatic and do not prevent progression or reverse the disease process. Compelling data show that intra-articular orthobiologic injections, such as platelet-rich plasma and mesenchymal stromal cells, are effective in providing relief of OA symptoms. However, recent data suggest that injections of orthobiologics into the subchondral bone may be superior to intra-articular injections for the management of OA. This review highlights the rationale and current evidence for intra-articular and subchondral bone injections of orthobiologics for the treatment of OA.

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.

Subchondral and intra-articular injections of bone marrow concentrate are a safe and effective treatment for knee osteoarthritis: a prospective, multi-center pilot study

PURPOSE

Subchondral bone is becoming a treatment target for knee OA patients, with promising early findings on the use of bone marrow aspirate concentrate (BMAC). The aim of this prospective, multi-centric pilot study was to evaluate safety as well as clinical and MRI outcomes of a combined approach of intra-articular and subchondral BMAC injections.

METHODS

Thirty patients (19 men, 11 women, 56.4 ± 8.1 years) with symptomatic knee OA were treated with a combination of an intra-articular and two subchondral BMAC injections (femoral condyle and tibial plateau). Patients were evaluated at baseline and at 1-3-6-12 months of follow-up with the IKDC subjective, VAS, KOOS, and EQ-VAS scores. The MRI evaluation was performed with the WORMS score.

RESULTS

No major complications were reported and only two patients were considered treatment failures, requiring a new injective or surgical treatment. The IKDC subjective score improved significantly from 40.5 ± 12.5 to 59.9 ± 16.1 at 3 months, 59.1 ± 12.2 at 6 months, and 62.6 ± 19.4 at 12 months (p < 0.0005). A similar improvement was reported for VAS pain and all KOOS subscales at all follow-ups, while EQ-VAS did not show any significant improvement. The MRI analysis showed a significant bone marrow edema reduction (p = 0.003), while the remaining WORMS parameters did not show any significant changes.

CONCLUSION

The pilot evaluation of this combined BMAC injective treatment showed safety and positive outcome up to 12 months of follow-up in patients with symptomatic knee OA associated with subchondral bone alterations. These findings suggest that targeting both subchondral bone and joint environment can provide promising results, and that BMAC can be a valid option for this combined approach to treat knee OA.

A Prospective Study Comparing Leukocyte-Poor Platelet-Rich Plasma Combined with Hyaluronic Acid and Autologous Microfragmented Adipose Tissue in Patients with Early Knee Osteoarthritis

The objective of this study was to compare the clinical efficacy of repeated doses of leucocyte-poor platelet-rich plasma (LP-PRP) plus hyaluronic acid (HA) to a single dose of autologous microfragmented adipose tissue (AMAT) injections in patients with early osteoarthritis (OA) symptoms. Eighty knees in 50 patients (mean age: 61.3 years) were randomly allocated into two equal groups in a nonblinded design and prospectively followed for 12 months. Group 1 received three intra-articular injections (1 month apart) using autologous LP-PRP+HA. Group 2 received a single dose of AMAT injection. Outcomes were measured by PROMs Tegner, Marx, visual analog scale, and Knee Injury and Osteoarthritis Outcome Score (KOOS) at 6 and 12 months. Both groups had significant clinical and functional improvement at 6 and 12 months. The differences between groups were statistically significant in Tegner score and KOOS symptoms (both P < 0.05) at 6 months in group 2. The test with statistically significant differences (P < 0.05) at 12 months was Tegner (P < 0.001), with group 2 having a higher median than group 1. LP-PRP+HA and AMAT lead to clinical and functional improvement at 6 and 12 months. AMAT showed better clinical results in Tegner and KOOS symptoms at 6 months and Tegner at 12 months. Understanding which therapy offers the most benefits with the least risk can significantly improve the quality of life for millions of people affected by OA. Long-term randomized controlled studies are needed to verify differences in efficacy.

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.

Phase II multicenter randomized controlled clinical trial on the efficacy of intra-articular injection of autologous bone marrow mesenchymal stem cells with platelet rich plasma for the treatment of knee osteoarthritis

Background

Mesenchymal stromal cells are a safe and promising option to treat knee osteoarthritis as previously demonstrated in different clinical trials. However, their efficacy, optimal dose and addition of adjuvants must be determined. Here, we evaluated the clinical effects of a dose of 100 × 10⁶ bone marrow mesenchymal stromal cells (BM-MSCs) in combination with Platelet Rich Plasma (PRGF®) as adjuvant in a randomized clinical trial.

Methods

A phase II, multicenter, randomized clinical trial with active control was conducted. Sixty patients diagnosed with knee OA were randomly assigned to 3 weekly doses of PRGF® or intraarticular administration of 100 × 10⁶ cultured autologous BM-MSCs plus PRGF®. Patients were followed up for 12 months, and pain and function were assessed using VAS and WOMAC and by measuring the knee range of motion range. X-ray and magnetic resonance imaging analyses were performed to analyze joint damage.

Results

No adverse effects were reported after BM-MSC administration or during follow-up. According to VAS, the mean value (SD) for PRGF® and BM-MSC with PRGF® went from 5 (1.8) to 4.5 (2.2) (p = 0.389) and from 5.3 (1.9) to 3.5 (2.5) (p = 0.01), respectively at 12 months. In WOMAC, the mean (SD) baseline and 12-month overall WOMAC scores in patients treated with PRGF® was 31.9 (16.2) and 22.3 (15.8) respectively (p = 0.002) while that for patients treated with BM-MSC plus PRGF® was 33.4 (18.7) and 23.0 (16.6) (p = 0.053). Although statistical significances between groups have been not detected, only patients being treated with BM-MSC plus PRGF® could be considered as a OA treatment responders following OARSI criteria. X-ray and MRI (WORMS protocol) revealed no changes in knee joint space width or joint damage.

Conclusions

Treatment with BM-MSC associated with PRGF® was shown to be a viable therapeutic option for osteoarthritis of the knee, with clinical improvement at the end of follow-up. Further phase III clinical trials would be necessary to confirm the efficacy.

Trial registration Clinical Trials.gov identifier NCT02365142. Nº EudraCT: 2011-006036-23

Biological and structural effects after intraosseous infiltrations of age-dependent platelet-rich plasma: An in vivo study

Platelet-rich plasma (PRP) is an increasingly widespread treatment for joint pathologies. Its characteristics and administration route are variables that may influence the clinical outcome. The aim of this in vivo study was to analyze in aged rats the biological and structure effects of intraosseous infiltrations of two different types of PRP obtained from young and old donors. During 6 months intraosseous infiltrations were performed and 4 days after the last infiltration, animals were sacrificed, and bones were extracted for micro-computed tomography (micro-CT) and histological analysis. Molecular composition of the PRP of aged donors presented higher levels of proinflammatory molecules. The histological studies showed a greater cellularity of bone marrow in groups treated with PRP. Concerning micro-CT analysis, young PRP showed a better femoral bone structure according to values of percentage of trabecular bone, trabecular space, trabecular density, and subchondral bone plate volume. In summary, this study has demonstrated that intraosseous infiltrations of PRP from young donors prevent from age-related bone degeneration. This treatment could stimulate the biological processes that maintain homeostasis and bone structure and avoid osteoarticular pathologies.

Platelet-rich plasma injections delay the need for knee arthroplasty: a retrospective study and survival analysis

PURPOSE

The biological action of platelet-rich plasma (PRP) could slow down the osteoarthritis progression, resulting in a delay of joint replacement. This work aims to evaluate the ability of PRP to postpone and even avoid knee replacement in patients with knee osteoarthritis (KOA) analyzing, on the one hand, the time of delay and on the other hand the percentage of patients without undergoing total knee arthroplasty (TKA).

METHODS

A retrospective analysis and a survival analysis were conducted. KOA patients who underwent knee replacement between 2014 and 2019 and previously received PRP infiltrations were included in the retrospective analysis. Regarding survival analysis, KOA patients who received PRP treatment during 2014 and with follow-up until 2019 were included. The dates of PRP treatment and TKA, KOA severity, age of the patients, number of PRP cycles, and administration route were analyzed.

RESULTS

This work included 1084 patients of which 667 met the inclusion criteria. 74.1% of the patients in the retrospective study achieved a delay in the TKA of more than 1.5 years, with a median delay of 5.3 years. The survival analysis showed that 85.7% of the patients did not undergo TKA during the five year follow-up. The severity degree, age, PRP cycles, and administration route had a statistically significant influence on the efficacy of PRP in delaying surgery.

CONCLUSION

These data suggest that the application of PRP in KOA patients is a treatment that could delay TKA, although further studies are needed to understand and improve this therapy.

Intraosseous infiltrations of Platelet-Rich Plasma for severe hip osteoarthritis: A pilot study

OBJECTIVE

Addressing the subchondral bone through intraosseous infiltrations of Platelet-Rich Plasma (PRP) may improve the effectiveness of this technique for severe hip osteoarthritis (HOA).

METHODS

Forty patients with HOA degree 2 and 3 according to the Tönnis scale were recruited for this study. They were susceptible to a total hip arthroplasty, without response to previous treatment based on intraarticular infiltrations of PRP. Patients received a combination of intraosseous injections into the acetabulum and the femoral head, as well as intraarticular PRP infiltrations. The clinical outcome was evaluated at 2, 6 and 12 months using the Hip Osteoarthritis Outcome Score (HOOS) and the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index.

RESULTS

At 2, 6 and 12 months, patients had significant pain improvement according to HOOS pain, WOMAC pain, and VAS scores. After the treatment, the percentage of patients with minimal clinically important improvement was 40% (16 over 40 patients) at 2 months, 37.5% (15 over 40) at 6 months, and 40% (16 over 40) at 12 months. Conclusion: The combination of intra-articular and intra-osseous infiltrations of PRP showed a pain reduction and improvement in hip joint functionality up to 12 months in patients with severe HOA, with no severe adverse effects.

Dose-Dependent Effects of Platelet-Rich Plasma Powder on Chondrocytes In Vitro

BACKGROUND

Platelet-rich plasma (PRP) is widely used in sports medicine. However, neither preparation nor parameters for clinical application, such as concentration, timing, and number of applications, are standardized, making research and clinical utilization challenging.

PURPOSE

To investigate the effect of varying doses of PRP powder in terms of different concentrations, timing, and number of applications on human chondrocytes in a reproducible cell culture model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A standardized lyophilized platelet growth factor preparation (PRP powder) was used to stimulate human chondrocytes. Chondrocytes were cultivated for 2 weeks with different stimulation frequencies (2×, 3×, 6×) and different concentrations of PRP powders (0.5%, 1%, 5%). Cell proliferation and metabolic cell activity were analyzed on days 7 and 14. Phenotypic changes were visualized through live-dead staining. Chondrogenic differentiation was quantified with enzyme-linked immunosorbent assay to assess the synthesis of procollagen types 1 and 2. Furthermore, sulfated proteoglycans and glycosaminoglycans were analyzed.

RESULTS

Human chondrocytes exhibited a significant dose- and time-dependent increase after 14 days in cell number (1% and 5% PRP powder vs unstimulated control: 7.95- and 15.45-fold increase, respectively; 2× vs 6× stimulation with 5% PRP powder: 4.00-fold increase) and metabolic cell activity (1% and 5% PRP powder vs unstimulated control: 3.27-fold and 3.58-fold change, respectively). Furthermore, cells revealed a significant increase in the amount of bone-specific procollagen type 1 (14 days, 1.94-fold) and sulfated glycosaminoglycans (14 days, 2.69-fold); however, no significant change was observed in the amount of cartilage-specific collagen type 2.

CONCLUSION

We showed that chondrocytes exhibit a significant dose- and time-dependent increase in cell number and metabolic cell activity. The standardized use of growth factor concentrates in cell culture models can contribute to clinical knowledge in terms of dosage and timing of PRP applications.

CLINICAL RELEVANCE

Problems with PRP, such as the absence of standardization, lack of consistency among studies, and unknown dosage, could be solved by using characterized PRP powder made by pooling and lyophilizing multiple platelet concentrates. The innovative PRP powder generates new possibilities for PRP research, as well as for the treatment of patients.

Vertebral intraosseous plasma rich in growth factor (PRGF-Endoret) infiltrations as a novel strategy for the treatment of degenerative lesions of endplate in lumbar pathology: description of technique and case presentation

BACKGROUND

Motivation and necessity to adopt minimally invasive therapies in the field of spinal regenerative medicine is increasing. Autologous platelet-rich plasma (PRP) therapy has recently been used as an effective technological and biological approach to tissue repair and has shown to improve multiple conditions including back pain and degenerative disc pathology. In addition, it is well established that the anatomic elements of the spinal system affected by degenerative pathology include the intervertebral disc (IVD) and vertebral subchondral bone (VSB), which play a crucial role in maintaining a healthy spinal column. Both elements are the target of a novel biological approach to the treatment of low back pain.

METHODS

A novel minimally invasive regenerative therapeutic approach is presented herein with a protocol based on combining vertebral intraosseous (VIO) and intradiscal (ID) infiltrations of plasma rich in growth factors (PRGF-Endoret), a type of leukocyte-free PRP, for the treatment of disc degeneration pathology.

RESULTS

We describe a novel technique applied in a patient treated for IVD degeneration and VSB damage, showing significant improvement on magnetic resonance imaging, including partial regression of protruded disc and significant resorption of intravertebral herniations (Schmörl's nodes), after PRGF therapy.

CONCLUSIONS

To the best of our knowledge, we present the first reported case description of the utilization of VIO and ID PRP infiltrations to treat protruded discs and intravertebral herniations with a successful clinical outcome.

Calcium phosphate injection of symptomatic bone marrow lesions of the knee: what is the current clinical evidence?

BACKGROUND

Chronic bone marrow lesions (BML) in the weight-bearing portions of the knee are often associated with symptomatic degenerative arthritis resulting in pain and dysfunction. Injection of bone substitute material like calcium phosphate has been described. Whilst some studies have reported encouraging results others have shown limited benefit of this technique.

AIM

The aim was to collate the available evidence on the injection of calcium phosphate and systematically evaluate the results to answer the questions encountered in clinical decision making: (1) does it provide effective long-lasting pain relief to avoid further surgical intervention? (2) which factors (patient/surgical) significantly influence the outcome? and (3) does it adversely affect the outcomes of subsequent arthroplasty?

METHODS

A literature search was performed to identify the studies describing the clinical outcomes of calcium phosphate injection for treatment of BML. We evaluated the reported clinical outcomes with respect to pain, function and complications. Isolated case reports and studies with no objective assessment of clinical outcomes were excluded.

RESULTS

We noted 46 articles in the current literature of which 8 described clinical outcomes of calcium phosphate injection. Mean (plus/minus SD) score on the visual analog scale (VAS) has been reported to improve from 7.90 (± 0.38) to 2.76 (± 0.90), whereas the International Knee Documentation Committee (IKDC) score improved from 30.5 (SD not reported (NR)) to 53.0 (SD NR). Pre and post procedure Short form survey (SF-12) scores were 29.8 (SD NR) and 36.7 (SD NR), respectively. In one study, scores on the Tegner Lysholm knee scoring scale improved in 12 out of 22 patients, whereas the remainder had no change in symptoms. Extravasation of calcium phosphate into the joint was the most common complication, whereas no adverse effect has been reported on subsequent arthroplasty.

CONCLUSION

Limited data from the published studies would suggest that calcium phosphate injection of BML may potentially improve pain and function. However, no evidence is currently available to clearly identify patient/surgical factors that may influence the long-term outcomes of this procedure. Hence pragmatic, prospective studies with stratified patient cohorts and robust reporting of outcome measures are essential to improve the understanding of the indications and clinical effectiveness of this novel procedure.

Effectiveness of intraosseous infiltration of autologous platelet-rich plasma in the area of the bone marrow edema in osteoarthritis of the knee joint

Osteoarthritis (OA) affects both elderly people, for whom it is one of the main causes of disability, and people of active working age and is an urgent clinical and social problem of resistance of pain syndrome to therapy. The disease is characterized by both destruction of intra-articular and paraarticular structures, such as subchondral bone. While OA is an important sign of pathological changes believe the bone marrow edema (BME). This work examines the effect of BME on development osteoarthritis, and therapeutic approaches to the management of patients with OA. The aim of the study was to develop a method of treatment of BME in OA of the knee joint by locally intraosseous injection of autologous thrombotic-rich plasma (PRP) into the edema zone. In this study 17 patients with the diagnosis: Osteoarthritis II-IV Grade. according to the classification of Kellgren–Lawrence, in which areas of local inflammation in the form of BME were detected on MRI in the subchondral zone in accordance with the international classification of WORMS (Whole Organ Magnetic Resonance Imaging Score). The mean age of patients was 41,7 ± 14,3 years, 10 of them were women and 7 men. Patients were treated with autological platelet-rich plasma under x-ray control injected from extra-articular intraosseous access in the area of BME. Evaluation of effectiveness of treatment performed by VAS, WOMAC and KOOS scales, before the introduction of autoplasma, after 1 and 3 months after the start of treatment. Three months after the manipulation, there was a statistically significant decrease in the intensity of inflammatory syndrome: for WOMAC by 17.5%, for KOOS by 19.4% and for VAS by 33,1% (p < 0,01). Thus, the efficiency of intraosseous Infiltration of autologous platelet-rich plasma in the treatment of patients with OA, accompanied by edema of the bone marrow in the subchondral zone, was proved.

Treating Severe Knee Osteoarthritis with Combination of Intra-Osseous and Intra-Articular Infiltrations of Platelet-Rich Plasma: An Observational Study

OBJECTIVE

Assessing the therapeutic effects of a combination of intra-articular and intra-osseous infiltrations of platelet-rich plasma (PRP) to treat severe knee osteoarthritis (KOA) using intra-articular injections of PRP as the control group.

DESIGN

In this observational study, 60 patients suffering from severe KOA were treated with intra-articular infiltrations of PRP (IA group) or with a combination of intra-osseous and intra-articular infiltrations of PRP (IO group). Both groups were matched for sex, age, body mass index, and radiographic severity (III and IV degree according to Ahlbäck scale). Clinical outcome was evaluated at 2, 6, and 12 months, using the Knee injury and Osteoarthritis Outcome Score (KOOS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaires.

RESULTS

At 2, 6 and 12 months after treatment, IO group had a significant improvement in all KOOS and WOMAC subscales ( P < 0.05). On the contrary, patients of the IA group did not improve in any of the scores. Sixteen out of 30 IO group patients showed minimal clinically important improvement (MCII) whereas 8 out of 30 IA group patients showed this response at 6 months (26.7%; 95% CI -0.4 to 49.9; P = 0.037). At 12 months, 14 patients of IO group and 5 patients of the IA group showed MCII (30%; 95% CI 4.3 to 51.9; P = 0.013). No differences between groups were observed at 2 months.

CONCLUSIONS

PRP intra-articular injections in severe KOA were not effective and did not provide any benefit. Combination of intra-articular and intra-osseous infiltrations of PRP was not clinically superior at 2 months, but it showed superior clinical outcomes at 6 and 12 months when compared with intra-articular injections of PRP.

Biologic Therapies for the Treatment of Knee Osteoarthritis

BACKGROUND

The use of biologic therapies for the management of knee osteoarthritis has increased, despite insufficient evidence of efficacy. Our aim was to complete a systematic review and analysis of reports utilizing the highest level-of-evidence evaluating: (1) platelet-rich plasma injections (PRPs); (2) bone marrow-derived mesenchymal stem cells (BMSCs); (3) adipose-derived mesenchymal stem cells (ADSCs); and (4) amnion-derived mesenchymal stem cells (AMSCs).

METHODS

PubMed, Embase, and Cochrane Library databases were queried for studies evaluating PRP injections, BMSCs, ADSCs, and AMSCs in patients with knee osteoarthritis. Of 1009 studies identified within the last 5 years, 123 met inclusion criteria. A comprehensive analysis of all levels-of-evidence was performed, as well as separate analysis on level-of-evidence I studies. Level-of-evidence was determined by the American Academy of Orthopedic Surgeons classification system.

RESULTS

Although the majority of PRP reports demonstrated improvements in pain and/or function, others revealed no substantial improvements. Similar findings were noted for BMSCs, ADSCs, and AMSCs. Assessments of BMSC studies yielded majority with positive clinical results, although short-lived. Studies on ADSCs revealed improved clinical outcomes, but equivocal radiographic outcomes. Studies evaluating AMSCs demonstrated improvements in pain and function, and decreased radiographic evidence of osteoarthritis.

CONCLUSION

Despite some promising early results for PRP, BMSC, ADSC, and AMSC therapies, the majority of level-of-evidence I studies have multiple problems: small sample sizes, potentially inappropriate control cohorts, short-term follow-up, and so on. Despite the limitations, there still appears to be evidence justifying their use for knee osteoarthritis management. More high-level, larger human studies utilizing standardized protocols are needed.

Current concepts in intraosseous Platelet-Rich Plasma injections for knee osteoarthritis

Knee osteoarthritis (OA) is a degenerative process that slowly destroys the joints producing pain and loss of function, and diminishes the quality of life. Current treatments alleviate this symptomatology but do not stop the disease, being total knee arthroplasty the only definitive solution. Among the emerging treatments, Platelet-Rich Plasma (PRP) has shown promising results in the treatment of OA. However, to improve its effectiveness, it is necessary to approach this pathology targeting the whole joint, not only the cartilage, but including other tissues such as subchondral bone. The pathological processes that occur in the subchondral bone have influence of the cartilage loss, aggravating the disease. The combination of intraarticular infiltrations with intraosseous infiltrations regulates the biological processes of the tissues, reducing the inflammatory environment and modulating the overexpression of biomolecules that generate an aberrant cellular behavior. Although the first clinical results using this technique are promising, further research and developing adequate protocols are necessary to achieve good clinical results.

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.

Platelet lysate enhances synovial fluid multipotential stromal cells functions: Implications for therapeutic use

BACKGROUND AIMS

Although intra-articular injection of platelet products is increasingly used for joint regenerative approaches, there are few data on their biological effects on joint-resident multipotential stromal cells (MSCs), which are directly exposed to the effects of these therapeutic strategies. Therefore, this study investigated the effect of platelet lysate (PL) on synovial fluid-derived MSCs (SF-MSCs), which in vivo have direct access to sites of cartilage injury.

METHODS

SF-MSCs were obtained during knee arthroscopic procedures (N = 7). Colony forming unit-fibroblast (CFU-F), flow-cytometric phenotyping, carboxyfluorescein succinimidyl ester-based immunomodulation for T-cell and trilineage differentiation assays were performed using PL and compared with standard conditions.

RESULTS

PL-enhanced SF-MSC (PL-MSC) proliferation as CFU-F colonies was 1.4-fold larger, and growing cultures had shorter population-doubling times. PL-MSCs and fetal calf serum (FCS)-MSCs had the same immunophenotype and similar immunomodulation activities. In chondrogenic and osteogenic differentiation assays, PL-MSCs produced 10% more sulfated-glycosaminoglycan (sGAG) and 45% less Ca⁺⁺ compared with FCS-MSCs, respectively. Replacing chondrogenic medium transforming growth factor-β3 with 20% or 50% PL further increased sGAG production of PL-MSCs by 69% and 95%, respectively, compared with complete chondrogenic medium. Also, Dulbecco's Modified Eagle's Medium high glucose (HG-DMEM) plus 50% PL induced more chondrogenesis compared with HG-DMEM plus 10% FCS and was comparable to complete chondrogenic medium.

CONCLUSIONS

This is the first study to assess SF-MSC responses to PL and provides biological support to the hypothesis that PL may be capable of modulating multiple functional aspects of joint resident MSCs with direct access to injured cartilage.

Comparison of hyaluronic acid and PRP intra-articular injection with combined intra-articular and intraosseous PRP injections to treat patients with knee osteoarthritis

The aim of this study was to evaluate the benefit provided by intraosseous infiltration combined with intra-articular injection of platelet-rich plasma to treat mild and moderate stages of knee joint degeneration (Kellgren-Lawrence score II-III) compared with other treatments, specifically intra-articular injection of PRP and of HA. Eighty-six patients with grade II to grade III knee OA according to the Kellgren-Lawrence classification were randomly assigned to intra-articular combined with intraosseous injection of PRP (group A), intra-articular PRP (group B), or intra-articular HA (group C). Patients in group A received intra-articular combined with intraosseous injection of PRP (administered twice, 2 weeks apart). Patients in group B received intra-articular injection of PRP every 14 days. Patients in group C received a series of five intra-articular injections of HA every 7 days. All patients were evaluated using the Visual Analogue Scale (VAS) and Western Ontario and McMaster Universities (WOMAC) score before the treatment and at 1, 3, 6, 12, and 18 months after treatment. There were significant improvements at the end of the 1st month. Notably, group A patients had significantly superior VAS and WOMAC scores than were observed in groups B and C. The VAS scores were similar in groups B and group C after the 6th month. Regarding the WOMAC scores, groups B and C differed at the 1st, 3rd, 6th, and 12th months; however, no significant difference was observed at the 18th month. The combination of intraosseous with intra-articular injections of PRP resulted in a significantly superior clinical outcome, with sustained lower VAS and WOMAC scores and improvement in quality of life within 18 months.

An optimised protocol for platelet-rich plasma preparation to improve its angiogenic and regenerative properties

Although platelet-rich plasma (PRP) is used as a source of growth factors in regenerative medicine, its effectiveness remains controversial, partially due to the absence of PRP preparation protocols based on the regenerative role of platelets. Here, we aimed to optimise the protocol by analysing PRP angiogenic and regenerative properties. Three optimising strategies were evaluated: dilution, 4 °C pre-incubation, and plasma cryoprecipitate supplementation. Following coagulation, PRP releasates (PRPr) were used to induce angiogenesis in vitro (HMEC-1 proliferation, migration, and tubule formation) and in vivo (chorioallantoic membrane), as well as regeneration of excisional wounds on mouse skin. Washed platelet releasates induced greater angiogenesis than PRPr due to the anti-angiogenic effect of plasma, which was decreased by diluting PRPr with saline. Angiogenesis was also improved by both PRP pre-incubation at 4 °C and cryoprecipitate supplementation. A combination of optimising variables exerted an additive effect, thereby increasing the angiogenic activity of PRPr from healthy donors and diabetic patients. Optimised PRPr induced faster and more efficient mouse skin wound repair compared to that induced by non-optimised PRPr. Acetylsalicylic acid inhibited angiogenesis and tissue regeneration mediated by PRPr; this inhibition was reversed following optimisation. Our findings indicate that PRP pre-incubation at 4 °C, PRPr dilution, and cryoprecipitate supplementation improve the angiogenic and regenerative properties of PRP compared to the obtained by current methods.

Biologic therapies to enhance intervertebral disc repair

Degenerative disc disease is a progressive, chronic disorder with strong association to pain, where the dysregulated tissue environment signals disc cells, thereby leading to a low inflammatory process and slow extracellular matrix degradation and fibrosis in a perpetual vicious cycle, generating a structural and functional failure of intervertebral disc joint (IVDJ). Among current biologic therapies, there is an emerging minimally invasive strategy that consists of infiltrating plasma rich in growth factors, a safe and efficacious therapeutic approach for other musculoskeletal degenerative conditions. This review summarizes the homeostasis and degeneration of IVDJ, discusses some results on basic science and therapeutic use of platelet-rich plasma products and advances an alternative minimally invasive biologic therapy in IVDJ degeneration and chronic back pain.

Targeting subchondral bone mesenchymal stem cell activities for intrinsic joint repair in osteoarthritis

Osteoarthritis (OA) is a common age-related disease with complex pathophysiology. It is characterized by wide-ranging tissue damage and ultimate biomechanical failure of the whole joint. However, signs of tissue adaptation and attempted repair responses are evident in OA-affected osteochondral tissues. Highlighted in this review article is the role of bone-resident mesenchymal stem cells (MSCs) in these bone remodeling responses, and a proposal that targeting MSC activities in OA subchondral bone could represent a novel approach for intrinsic joint regeneration in OA. The development of these therapies will require better understanding of MSC proliferation, migration and differentiation patterns in relation to OA tissue damage and further clarification of the molecular signaling events in these MSCs during disease progression.

Osteoarthritis (OA) is a joint disorder, in which the cartilage, the underlying bone and other joint tissues are affected. Recent evidence demonstrating attempted repair responses in these OA tissues challenges the traditional view of OA as a degenerative disorder. Signs of tissue regeneration are particularly evident in the bone located directly underneath the damaged cartilage, where increased stem cell activity has been observed. Targeting these stem cells could represent a novel approach for intrinsic joint regeneration in OA. To progress with developing these novel therapies, a better understanding of stem cell function in normal and OA joint tissues is needed.

Intraosseous Infiltration of Platelet-Rich Plasma for Severe Hip Osteoarthritis

This work describes a technique of platelet-rich plasma (PRP) infiltration for the treatment of severe hip osteoarthritis (OA). Although the results achieved with intra-articular infiltrations of PRP are promising, they may be insufficient in the long-term for severe hip OA. The technique consists of a combined intra-articular and intraosseous infiltration of PRP to reach all joint tissues, especially the subchondral bone, and hence facilitate a greater distribution of PRP. Diagnosis is based on clinical and radiographic findings, and patients with grade III OA according to the Tönnis scale, as well as patients who have not responded to conventional treatment, are considered candidates for this technique. After an ultrasound-guided intra-articular PRP infiltration is performed, 2 intraosseous infiltrations are conducted with a fluoroscope; the first injection is applied into the acetabulum and the second into the femoral head. However, this technique presents more difficulty than the conventional administration, so it is necessary to consider several aspects described in this work.

Combination of Intra-Articular and Intraosseous Injections of Platelet Rich Plasma for Severe Knee Osteoarthritis: A Pilot Study

The aim of this study was to assess a novel approach to treating severe knee osteoarthritis by targeting synovial membrane, superficial articular cartilage, synovial fluid, and subchondral bone by combining intra-articular injections and intraosseous infiltrations of platelet rich plasma. We explored a new strategy consisting of intraosseous infiltrations of platelet rich plasma into the subchondral bone in combination with the conventional intra-articular injection in order to tackle several knee joint tissues simultaneously. We assessed the clinical outcomes through osteoarthritis outcome score (KOOS) and the inflammatory response by quantifying mesenchymal stem cells in synovial fluid. There was a significant pain reduction in the KOOS from baseline (61.55 ± 14.11) to week 24 (74.60 ± 19.19), after treatment (p = 0.008), in the secondary outcomes (symptoms, p = 0.004; ADL, p = 0.022; sport/rec., p = 0.017; QOL, p = 0.012), as well as VAS score (p < 0.001) and Lequesne Index (p = 0.008). The presence of mesenchymal stem cells in synovial fluid and colony-forming cells one week after treatment decreased substantially from 7.98 ± 8.21 MSC/μL to 4.04 ± 5.36 MSC/μL (p = 0.019) and from 601.75 ± 312.30 to 139.19 ± 123.61  (p = 0.012), respectively. Intra-articular injections combined with intraosseous infiltrations of platelet rich plasma reduce pain and mesenchymal stem cells in synovial fluid, besides significantly improving knee joint function in patients with severe knee osteoarthritis. This trial is registered on EudraCT with the number 2013-003982-32.