The effect of platelet-rich plasma on the regenerative therapy of muscle derived stem cells for articular cartilage repair

Development of scaffold-free tissue-engineered constructs derived from mesenchymal stem cells with serum-free media for cartilage repair and long-term preservation

Synovial mesenchymal stem cells (sMSCs) have great potential for cartilage repair, but their therapeutic design to avoid adverse effects associated with unknown factors remains a challenge. In addition, because long-term preservation is indispensable to maintain high quality levels until implantation, it is necessary to reduce their fluctuations. This study aimed to investigate the properties and feasibility of novel scaffold-free tissue-engineered constructs using serum-free media and to develop long-term preservation methods. sMSCs were cultured in serum-free media, seeded at high density in a monolayer, and finally developed as a sheet-like construct called "gMSC1". The properties of frozen gMSC1 (Fro-gMSC1) were compared with those of refrigerated gMSC1 (Ref-gMSC1) and then examined by their profile. Chondrogenic differentiation potential was analyzed by quantitative real-time polymerase chain reaction and quantification of glycosaminoglycan content. Xenografts into the cartilage defect model in rats were evaluated by histological staining. gMSC1 showed nearly similar properties independent of the preservation conditions. The animal experiment demonstrated that the defect could be filled with cartilage-like tissue with good integration to the adjacent tissue, suggesting that gMSC1 was formed and replaced the cartilage. Furthermore, several chondrogenesis-related factors were significantly secreted inside and outside gMSC1. Morphological analysis of Fro-gMSC1 revealed comparable quality levels to those of fresh gMSC1. Thus, if cryopreserved, gMSC1, with no complicated materials or processes, could have sustained cartilage repair capacity. gMSC1 is a prominent candidate in novel clinical practice for cartilage repair, allowing for large quantities to be manufactured at one time and preserved for a long term by freezing.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-024-00637-y.

Cell-based therapies have disease-modifying effects on osteoarthritis in animal models: A systematic review by the ESSKA Orthobiologic Initiative. Part 3: Umbilical cord, placenta, and other sources for cell-based injectable therapies

PURPOSE

This systematic review aimed to investigate in animal models the presence of disease-modifying effects driven by non-bone marrow-derived and non-adipose-derived products, with a particular focus on umbilical cord and placenta-derived cell-based therapies for the intra-articular injective treatment of osteoarthritis (OA).

METHODS

A systematic review was performed on three electronic databases (PubMed, Web of Science and Embase) according to PRISMA guidelines. The results were synthesised to investigate disease-modifying effects in preclinical animal studies comparing injectable umbilical cord, placenta, and other sources-derived products with OA controls. The risk of bias was assessed using the SYRCLE tool.

RESULTS

A total of 80 studies were included (2314 animals). Cell therapies were most commonly obtained from the umbilical cord in 33 studies and placenta/amniotic tissue in 18. Cell products were xenogeneic in 61 studies and allogeneic in the remaining 19 studies. Overall, 25/27 (92.6%) of studies on umbilical cord-derived products documented better results compared to OA controls in at least one of the following outcomes: macroscopic, histological and/or immunohistochemical findings, with 19/22 of studies (83.4%) show positive results at the cartilage level and 4/6 of studies (66.7%) at the synovial level. Placenta-derived injectable products documented positive results in 13/16 (81.3%) of the studies, 12/15 (80.0%) at the cartilage level, and 2/4 (50.0%) at the synovial level, but 2/16 studies (12.5%) found overall worse results than OA controls. Other sources (embryonic, synovial, peripheral blood, dental pulp, cartilage, meniscus and muscle-derived products) were investigated in fewer preclinical studies. The risk of bias was low in 42% of items, unclear in 49%, and high in 9% of items.

CONCLUSION

Interest in cell-based injectable therapies for OA treatment is soaring, particularly for alternatives to bone marrow and adipose tissue. While expanded umbilical cord mesenchymal stem cells reported auspicious disease-modifying effects in preventing OA progression in animal models, placenta/amniotic tissue also reported deleterious effects on OA joints. Lower evidence has been found for other cellular sources such as embryonic, synovial, peripheral blood, dental-pulp, cartilage, meniscus, and muscle-derived products.

LEVEL OF EVIDENCE

Level II.

Exploring Platelet-Rich Plasma Therapy for Knee Osteoarthritis: An In-Depth Analysis

The use of platelet-rich plasma (PRP) in all medical fields is currently gaining popularity (1). PRP is a biological product that can be defined as a segment of the plasma fraction of autologous blood with a platelet concentration level above the baseline (2). The fact that it has uses in tissue regeneration and wound healing has caught the eye of orthopedic surgeons as well, as intra-articular treatments have continued to evolve. Its benefits in the treatment of different osteoarticular pathologies are of great interest in the evolving orthopedic community, targeting mostly knee osteoarthritis, meniscus and ligament injuries (3). The purpose of this review is to update the reader on the current uses of platelet-rich plasma (PRP) in the treatment of knee osteoarthritis pathology and to provide clinical feedback on its uses in the fields of orthopedic and sports medicine practice (4). We proceeded in studying 180 titles and abstracts eligible for inclusion. Compared to alternative treatments, PRP injections greatly improve the function of the knee joint.

The use of platelet rich plasma in the treatment of degenerative joint disease in cats: an exploratory case series

Objective

To evaluate the effectiveness of intra-articular autologous Platelet Rich Plasma (PRP) in managing Degenerative Joint Disease (DJD) in cats.

Design

Prospective pilot clinical trial.

Methods

Six domestic cats with clinically and radiographically diagnosed DJD received intra-articular injections of autologous PRP. Clinical assessments pre and post intra-articular injections were conducted using the Feline Musculoskeletal Pain Index (FMPI, owner assessed) and Visual Analog Scale (VAS, clinician assessed) at baseline, Day 14, Day 28, and Day 42-45.

Results

Significant improvements were noted in both FMPI and VAS scores at the end of the study period, indicating enhanced joint function and reduced pain.

Conclusion and clinical relevance

The study suggests the potential of PRP therapy as a safe and effective treatment for feline DJD, warranting further research with larger cohorts and longer follow-up to establish comprehensive treatment guidelines.

Liquid platelet-rich fibrin produced via horizontal centrifugation decreases the inflammatory response and promotes chondrocyte regeneration in vitro

Objective: Recently, liquid platelet-rich fibrin (PRF), a rich source of concentrated platelets and growth factors, has emerged as a promising agent for stimulating tissue regeneration. However, its specific efficacy in chondrocyte proliferation and cartilage regeneration remains underexplored. To address this question, we investigated liquid PRF obtained through horizontal centrifugation and compared its effects with hyaluronic acid (HA), a high molecular weight glucosamine supplement widely used in clinical practice to safeguard against chondral damage. Materials and Methods: Liquid PRF, produced using horizontal centrifugation (liquid H-PRF) at 500 g for 8 min, served as our experimental agent. We conducted cell viability and proliferation assays using PRF-conditioned medium. We assessed the chondrocyte phenotype of ATDC5 cells through toluidine blue and alcian blue staining, real-time polymerase chain reaction (RT-PCR), Western blotting, and immunofluorescence staining. Furthermore, we examined the expression of genes involved in inflammation through RT-PCR and Western blot analysis. Results: Liquid H-PRF exerted notable effects on chondrocytes, influencing proliferation, inflammatory responses, and chondrogenic differentiation. The H-PRF group displayed significantly higher expression of chondrogenic markers, including Col2a1, compared to HA-treated cells, whereas aggrecan expression was significantly higher in the HA group. PRF also demonstrated the ability to reduce inflammatory levels in chondrogenic ATDC5 cells, and this effect was further enhanced when PRF from the buffy coat zone was added. In comparison, chondrocytes cultured in the HA group produced significantly fewer inflammatory factors than those in the PRF group, as confirmed qualitatively by Western blot analysis. Conclusion: Liquid H-PRF emerged as a potent stimulator for chondrogenesis and a regulator of the inflammatory response, achieving levels similar to HA. Moreover, liquid H-PRF exhibited strong potential for enhancing the production of cartilage extracellular matrix and promoting chondrogenic regeneration with notably increased Col2a1 levels. Future research should encompass animal studies and human trials to further evaluate the comparative effectiveness of liquid PRF versus HA, potentially as an alternative or complementary strategy for future clinical applications.

Infiltration therapy in the context of cartilage surgery

Guideline-based surgical cartilage therapy for focal cartilage damage offers highly effective possibilities to sustainably reduce patients' complaints and to prevent or at least delay the development of early osteoarthritis. In the knee joint, it has the potential to reduce almost a quarter of the arthroses requiring joint replacement caused by cartilage damage. Biologically effective injection therapies could further improve these results. Based on the currently available literature and preclinical studies, intra- and postoperative injectables may have a positive effect of platelet-rich plasma/fibrin (PRP/PRF) and hyaluronic acid (HA) on cartilage regeneration and, in the case of HA injections, also on the clinical outcome can be assumed. The role of a combination therapy with use of intra-articular corticosteroids is lacking in the absence of adequate study data and cannot be defined yet. With regard to adipose tissue-based cell therapy, the current scientific data do not yet justify any recommendation for its use. Further studies also regarding application intervals, timing and differences in different joints are required.

Leukocyte-Rich Platelet-Rich Plasma Is Predominantly Anti-inflammatory Compared With Leukocyte-Poor Platelet-Rich Plasma in Patients With Mild-Moderate Knee Osteoarthritis: A Prospective, Descriptive Laboratory Study

BACKGROUND

Platelet-rich plasma (PRP) has been used extensively in clinical practice to treat patients with symptomatic knee osteoarthritis (OA). Leukocyte-poor PRP (LP-PRP) has been clinically preferred over leukocyte-rich PRP (LR-PRP); however, it is unclear which cytokine mediators of pain and inflammation are present in LR-PRP and LP-PRP from patients with mild to moderate knee OA in order to rationalize a specific formulation.

HYPOTHESIS

LP-PRP would be predominantly anti-inflammatory and have reduced nociceptive pain mediators compared with LR-PRP from the same individual with mild to moderate knee OA.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 24 unique samples of PRP were prepared in order to assess 48 samples of LR-PRP and LP-PRP taken from 12 patients (6 male and 6 female) with symptomatic knee OA of Kellgren-Lawrence grade 2 to 3. Patients underwent blood collection for LR-PRP and LP-PRP preparation through a double-spin protocol to obtain baseline whole blood, platelet concentration, and white blood cell subtypes. LR-PRP and LP-PRP from the same patient were produced at the same time and underwent a comprehensive panel through Luminex (multicytokine profiling) to assess key mediators of inflammation: interleukin 1 receptor antagonist (IL-1Ra), interleukin 4, 6, 8, and 10 (IL-4, IL-6, IL-8, and IL-10), IL-1β, tissue necrosis factor α (TNF-α), and matrix metalloproteinase 9 (MMP-9). To assess mediators of nociceptive pain, nerve growth factor (NGF) and tartrate resistant acid phosphatase 5 (TRAP5) were also assessed.

RESULTS

LR-PRP from patients with mild to moderate knee OA expressed significantly more IL-1Ra, IL-4, IL-8, and MMP-9 compared with LP-PRP formulations from the same patients. No significant differences were found between LR-PRP and LP-PRP in mediators of nociceptive pain-namely, NGF and TRAP5. Other mediators including TNF-α, IL-1β, IL-6, and IL-10 were also found to have no significant expression differences between LR-PRP and LP-PRP.

CONCLUSION

LR-PRP expressed significantly more IL-1Ra, IL-4, and IL-8, suggesting that LR-PRP may be more anti-inflammatory than LP-PRP. MMP-9 was expressed in higher concentrations in LR-PRP, suggesting that LR-PRP may be more chondrotoxic than LP-PRP.

CLINICAL RELEVANCE

LR-PRP was found to have a robust expression of anti-inflammatory mediators compared with LP-PRP and may be beneficial to patients with long-term knee OA where chronic low-grade inflammation is present. Mechanistic clinical trials are needed to elucidate the key mediators in both LR-PRP and LP-PRP to assess their effect on long-term progression of knee OA.

Effectiveness of platelet-rich plasma in the treatment of Achilles tendon disease

BACKGROUND

The effectiveness of Platelet-Rich Plasma (PRP) in the treatment of patients with Achilles tendon rupture (ATR) and Achilles tendinopathy (AT) has been controversial.

AIM

To assess PRP injections’ effectiveness in treating ATR and AT.

METHODS

A comprehensive review of relevant literature was conducted utilizing multiple databases such as Cochrane Library, PubMed, Web of Science, Chinese Science and Technology Journal, EMBASE, and China Biomedical CD-ROM. The present investigation integrated randomized controlled trials that assessed the effectiveness of platelet-rich plasma injections in managing individuals with Achilles tendon rupture and tendinopathy. The eligibility criteria for the trials encompassed publications that were published within the timeframe of January 1, 1966 to December 2022. The statistical analysis was performed utilizing the Review Manager 5.4.1, the visual analogue scale (VAS), Victorian Institute Ankle Function Scale (VISA-A), and Achilles Tendon Thickness were used to assess outcomes.

RESULTS

This meta-analysis included 13 randomized controlled trials, 8 of which were randomized controlled trials of PRP for AT and 5 of which were randomized controlled trials of PRP for ATR. PRP for AT at 6 wk [weighted mean difference (WMD) = 1.92, 95%CI: -0.54 to 4.38, I² = 34%], at 3 mo [WMD = 0.20, 95%CI: -2.65 to 3.05, I² = 60%], and 6 mo [WMD = 2.75, 95%CI: -2.76 to 8.26, I² = 87%) after which there was no significant difference in VISA-A scores between the PRP and control groups. There was no significant difference in VAS scores between the PRP group and the control group after 6 wk [WMD = 6.75, 95%CI: -6.12 to 19.62, I² = 69%] and 6 mo [WMD = 10.46, 95%CI: -2.44 to 23.37, I² = 69%] of treatment, and at mid-treatment at 3 mo [WMD = 11.30, 95%CI: 7.33 to 15.27, I² = 0%] after mid-treatment, the PRP group demonstrated better outcomes than the control group. Post-treatment patient satisfaction [WMD = 1.07, 95%CI: 0.84 to 1.35, I² = 0%], Achilles tendon thickness [WMD = 0.34, 95%CI: -0.04 to 0.71, I² = 61%] and return to sport [WMD = 1.11, 95%CI: 0.87 to 1.42, I² = 0%] were not significantly different between the PRP and control groups. The study did not find any statistically significant distinction between the groups that received PRP treatment and those that did not, regarding the Victorian Institute of Sport Assessment - Achilles scores at 3 mo [WMD = -1.49, 95%CI: -5.24 to 2.25, I² = 0%], 6 mo [WMD = -0.24, 95%CI: -3.80 to 3.32, I² = 0%], and 12 mo [WMD = -2.02, 95%CI: -5.34 to 1.29, I² = 87%] for ATR patients. Additionally, no significant difference was observed between the PRP and the control groups in improving Heel lift height respectively at 6 mo [WMD = -3.96, 95%CI: -8.61 to 0.69, I² = 0%] and 12 mo [WMD = -1.66, 95%CI: -11.15 to 7.83, I² = 0%] for ATR patients. There was no significant difference in calf circumference between the PRP group and the control group after 6 mo [WMD = 1.01, 95%CI: -0.78 to 2.80, I² = 54%] and 12 mo [WMD = -0.55, 95%CI: -2.2 to 1.09, I² = 0%] of treatment. There was no significant difference in ankle mobility between the PRP and control groups at 6 mo of treatment [WMD = -0.38, 95%CI: -2.34 to 1.58, I² = 82%] and after 12 mo of treatment [WMD = -0.98, 95%CI: -1.41 to -0.56, I² = 10%] there was a significant improvement in ankle mobility between the PRP and control groups. There was no significant difference in the rate of return to exercise after treatment [WMD = 1.20, 95%CI: 0.77 to 1.87, I² = 0%] and the rate of adverse events [WMD = 0.85, 95%CI: 0.50 to 1.45, I² = 0%] between the PRP group and the control group.

CONCLUSION

The use of PRP for AT improved the patient’s immediate VAS scores but not VISA-A scores, changes in Achilles tendon thickness, patient satisfaction, or return to sport. Treatment of ATR with PRP injections alone improved long-term ankle mobility but had no significant effect on VISA-A scores, single heel lift height, calf circumference or return to sport. Additional research employing more extensive sampling sizes, more strict experimental methods, and standard methodologies may be necessary to yield more dependable and precise findings.

Leukocyte-Rich vs. Leukocyte-Poor Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis

Knee osteoarthritis (OA) is a well-established form of OA and accounts for nearly 4/5 of global OA burden […].

Clinical benefit of high tibial osteotomy combined with the intervention of platelet-rich plasma for severe knee osteoarthritis

PURPOSE

The objective of present study was to investigate the therapeutic effects of high tibial osteotomy (HTO) combined with platelet-rich plasma (PRP) for severe knee osteoarthritis (KOA).

METHODS

This was a double-blinded, randomized, placebo-controlled trial. The participants were randomly divided by computerderived random charts into 3 groups: 24 participants in group A (24 knees) received a treatment option of HTO combined with PRP, 25 participants in group B (25 knees) received a treatment program of HTO combined with hyaluronic acid, and 25 participants in group C (25 knees) received a treatment method of HTO combined with normal saline (NS) (physiological control/placebo). The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and visual analog scale (VAS) were measured preoperatively and at the final follow-up. Status of articular cartilage was assessed according to the International Cartilage Repair Society grade and the presence of newly formed cartilaginous tissue by arthroscopy. MRI was completed of knee joint to measure the cartilaginous thickness.

RESULTS

Compared to Group B and C, the final follow-up results of knee function in Group A were significantly different (P < 0.001), such as the total WOMAC score 18.54 (SD 4.17), the VAS score 1.72 (SD 0.53). Cartilage regeneration of femur and tibia in Group A was observed in all patients. The cartilaginous thickness in Group A were significantly different (P < 0.001), such as the anterior patella femoral region 3.52 (SD 0.47), the anterior meniscal region 1.16 (SD 0.24), the posterior meniscal region 1.24 (SD 0.26) and the posterior condyle region 2.25 (SD 0.31).

CONCLUSIONS

The addition of combined PRP to HTO may be a more reasonable choice to relieve knee pain and decelerate the progression of the medial KOA.

The Clinical Efficacy of Platelet-Rich Plasma versus Conventional Drug Injection in the Treatment of Knee Osteoarthritis: A Study Protocol for a Randomized Controlled Trial

Knee osteoarthritis is a common chronic degenerative joint disease in middle-aged and elderly people. Intra-articular injection for the treatment of knee osteoarthritis is a regularly utilized nonsurgical treatment in modern medicine. Hyaluronic acid (HA) and platelet-rich plasma (PRP) are two frequently employed intra-articular devices. Hyaluronic acid (HA) is an accepted nonsurgical treatment for symptomatic KOA, and platelet-rich plasma is a popular option in the treatment of KOA in recent years. The purpose of this research is to compare the efficacy and safety of intra-articular injection of platelet-rich plasma (PRP) versus hyaluronic acid (HA) on the pain score scale, knee function, and related inflammatory biomarkers in KOA patients using a clinical randomized controlled trial. Participants are being randomized into either the hyaluronic acid (HA) or into the platelet-rich plasma (PRP) group. All patients receive 4 weeks of treatment (once a week), and well-being support and quadriceps training (3 times a week). The primary outcomes are measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the visual analog scale (VAS). The secondary outcomes include the activities of daily living score, erythrocyte sedimentation rate, C-reactive protein testing, interleukin-6 levels, and X-ray examination. In order to monitor the occurrence of irregularities and abnormalities, patients are assessed at each visit, and restorative treatment is given if necessary. The results of this clinical trial will verify the efficacy of PRP and HA in the treatment of KOA and provide important evidence for the clinical treatment of KOA. The trial was enlisted at the Chinese Clinical Trial Registry on 26 September 2020 (ChiCTR2000038635).

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.

Real-world evidence of mesenchymal stem cell therapy in knee osteoarthritis: a large prospective two-year case series

Objective: To evaluate the long-term safety and efficacy of adipose-derived mesenchymal stem cell (ADMSC) therapy in the treatment of knee osteoarthritis (OA). Methods: 329 participants with knee OA underwent intra-articular ADMSC therapy. Participants were followed up for 24 months and were separated based on radiological OA grade. Results: Treatment was well tolerated with no related serious adverse events. All participant groups reported clinically and statistically significant pain improvement. Clinical outcome was not influenced by patients' age or BMI. Conclusion: ADMSC therapy is an effective, safe and long-lasting treatment option for knee OA with the potential to delay total joint replacement. In addition to the observed clinical benefits, ADMSC therapy promises to reduce the global economic burden of OA. Trial registration number: ACTRN12617000638336.

Overview of First-Line and Second-Line Pharmacotherapies for Osteoarthritis with Special Focus on Intra-Articular Treatment

Osteoarthritis (OA) can be defined as the result of pathological processes of various etiologies leading to damage to the articular structures. Although the mechanism of degenerative changes has become better understood due to the plethora of biochemical and genetic studies, the drug that could stop the degenerative cascade is still unknown. All available forms of OA therapy are based on symptomatic treatment. According to actual guidelines, comprehensive treatment of OA should always include a combination of various therapeutic options aimed at common goals, which are pain relief in the first place, and then the improvement of function. Local treatment has become more common practice, which takes place between rehabilitation and pharmacological treatment in the hierarchy of procedures. Only in the case of no improvement and the presence of advanced lesions visible in imaging tests, should surgery be considered. Currently, an increasing number of studies are being published suggesting that intra-articular injections may be as effective or even more effective than non-steroidal anti-inflammatory drugs (NSAIDs) and result in fewer systemic adverse events. The most commonly used preparations are hyaluronic acid (HA), glucocorticosteroids (GS), and also platelet-rich plasma (PRP) in recent years. This review aims to present the mechanism of action and clinical effectiveness of different pharmacological options in relieving pain and improving functions in OA as well as the emerging approach in intra-articular treatment with PRP.

Platelet-rich plasma injections induce disease-modifying effects in the treatment of osteoarthritis in animal models

PURPOSE

The mechanisms of action and disease-modifying potential of platelet-rich plasma (PRP) injection for osteoarthritis (OA) treatment are still not fully established. The aim of this systematic review of preclinical evidence was to determine if PRP injections can induce disease-modifying effects in OA joints.

METHODS

A systematic review was performed on animal studies evaluating intra-articular PRP injections as treatment for OA joints. A synthesis of the results was performed investigating the disease-modifying effects of PRP by evaluating studies that compared PRP with OA controls or other injectable products, different PRP formulations or injection intervals, and the combination of PRP with other products. The risk of bias was assessed according to the SYRCLE's tool.

RESULTS

Forty-four articles were included, for a total of 1251 animals. The publication trend remarkably increased over time. PRP injections showed clinical effects in 80% and disease-modifying effects in 68% of the studies, attenuating cartilage damage progression and reducing synovial inflammation, coupled with changes in biomarker levels. Evidence is limited on the best PRP formulation, injection intervals, and synergistic effect with other injectables. The risk of bias was low in 40%, unclear in 56%, and high in 4% of items.

CONCLUSION

Intra-articular PRP injections showed disease-modifying effects in most studies, both at the cartilage and synovial level. These findings in animal OA models can play a crucial role in understanding mechanism of action and structural effects of this biological approach. Nevertheless, the overall low quality of the published studies warrants further preclinical studies to confirm the positive findings, as well as high-level human trials to demonstrate if these results translate into disease-modifying effects when PRP is used in the clinical practice to treat OA.

LEVEL OF EVIDENCE

Level II.

Effects of Platelet-Rich Plasma and Bone Marrow Mesenchymal Stem Cells on Meniscal Repair in the White-White Zone of the Meniscus

Objective

To investigate the role of autologous platelet‐rich plasma (PRP) on the repair of meniscal white‐white zone injury through promoting the proliferation of canine bone marrow‐derived mesenchymal stem cells (BMSCs).

Methods

A total of 24 beagle dogs were selected to construct meniscal white‐white zone injury models in both lateral knee joints. All subjects were divided into four groups: control, BMSCs, PRP, and PRP + BMSCs. Immunohistochemistry was applied in the expression detection of type I and type II collagens. HE staining and methylene blue staining were performed to observe the injury of cartilage of lateral femoral condyle in each group. ELISA was used to detect the osteopontin (OPN) content in cartilage of lateral femoral condyle. HE staining and magnetic resonance imaging (MRI) were used to observe the healing of meniscus in each group. Outcome measures include the expression of OPN in the synovial fluid of knee joint, the expression of type I collagen and type II collagen, the healing of meniscus injury, and the damage degree of lateral femoral condyle cartilage.

Results

Compared with the control group, the expressions of type I and type II collagens were enhanced in the PRP group and the PRP + BMSCs group. Compared with 1 week before modeling, the expression of OPN was elevated in the control group and the BMSCs group at 3 weeks after modeling. There were no significant differences in the above indicators between the PRP group and the PRP + BMSCs group. According to MRI and pathological section after HE staining, meniscal healing in the PRP group and the PRP + BMSCs group was significantly improved as compared to that of the control group and the BMSCs group (all P < 0.05), and there was no significant difference between the PRP group and the PRP + BMSCs group (P > 0.05). All subjects were divided into the non‐healing group and the healing group in accordance with the HE staining results in previous experiment. The injury of cartilage of lateral femoral condyle was significantly heavier in the non‐healing group than that in the healing group.

Conclusion

The application of PRP alone or in combination with BMSCs could promote the clinical healing rate of meniscal white‐white zone injury.

Effectiveness of platelet-rich plasma injections for the treatment of acute Achilles tendon rupture: A systematic review and meta-analysis

BACKGROUND

The effect of platelet-rich plasma (PRP) on patients with acute Achilles tendon rupture is still controversial. The purpose of this systematic review is to assess the efficacy of PRP injections treating acute Achilles tendon rupture.

METHODS

A comprehensive electronic literature search was performed in the PubMed, Embase, Cochrane Library, and Web of Science databases to identify relevant studies that were published prior to April 29, 2021. Randomized controlled trials evaluating the efficacy of PRP injections in treating patients with acute Achilles tendon rupture were included. Statistical analyses were conducted using RevMan software.

RESULTS

Five randomized controlled trials were included in this systematic review. The results of the meta-analysis showed that PRP has positive effects on ankle dorsiflexion angle, dorsal extension strength of the ankle, and calf circumference compared with that in controls. However, the current evidence failed to show that PRP effectively improves ankle plantar flexion angle, plantar flexion strength of the ankle, and pain.

CONCLUSIONS

PRP injections for the treatment of acute Achilles tendon rupture significantly improved ankle dorsiflexion angle, dorsal extension strength of the ankle, and calf circumference compared with that in controls. Additional studies with larger sample sizes, more rigorous designs and standardized protocols are needed to draw more reliable and accurate conclusions.

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.

Adverse Reactions and Clinical Outcomes for Leukocyte-Poor Versus Leukocyte-Rich Platelet-Rich Plasma in Knee Osteoarthritis: A Systematic Review and Meta-analysis

Background:

Platelet-rich plasma (PRP) has gained attention as a therapeutic option for knee osteoarthritis; however, its efficacy varies widely. Leukocytes in PRP raise the concern of aggravating proinflammatory activity. To date, PRP has rarely been investigated with regard to leukocyte concentration.

Purpose:

To provide clinical evidence of the intra-articular injection of PRPs containing different leukocyte concentrations.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

We systematically searched the MEDLINE, Embase, Cochrane Library, CINAHL, and Scopus databases. PRP was classified into leukocyte-poor (LP-PRP) and leukocyte-rich (LR-PRP). Clinical outcomes including Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analog scale (VAS) for pain score, International Knee Documentation Committee (IKDC) subjective score, and adverse reactions were evaluated. The Methodological Index for Non-Randomized Studies criteria were used for quality assessment.

Results:

Included were 32 studies with an evidence level between 1 and 4. Both LP-PRP and LR-PRP showed improvements above the minimal clinically important difference (MCID) in VAS pain score. No significant intergroup difference was seen at 3, 6, or 12 months of follow-up. Regarding function, both LP-PRP and LR-PRP showed improvements above the MCID in the WOMAC and IKDC scores, with no significant difference between the groups. Adverse reactions for pain were significantly higher in LR-PRP than in LP-PRP (odds ratio, 1.64; 95% confidence interval, 1.29-2.10; P = .01). After intra-articular PRP injection, LR-PRP showed a significantly higher rate of swelling than LP-PRP (odds ratio, 1.56; 95% confidence interval, 1.22-1.99; P = .02). The mean Methodological Index for Non-Randomized Studies score of the included studies was 18.6 (range, 10-24).

Conclusion:

Intra-articular PRP injection resulted in improvements above the MCID in terms of pain and function in patients with knee osteoarthritis up to 12 months. The risk of local adverse reactions appeared to be increased after LR-PRP compared with LP-PRP injection. The findings of this review can support the potential use of intra-articular PRP injection for the treatment of knee osteoarthritis. In clinical application, clinicians need to consider selecting a specific type of PRP for knee osteoarthritis.

Therapeutic Effects of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Combined with Cartilage Acellular Matrix Mediated Via Bone Morphogenic Protein 6 in a Rabbit Model of Articular Cruciate Ligament Transection

Osteoarthritis (OA) is a general joint disease. Cartilage damage is associated with a decrease in the density of chondrocytes. Mesenchymal stem cells (MSCs) differentiate into adipocytes, osteocytes and chondrocytes, and are an excellent source of cell therapy. Cartilage-derived extracellular matrix (ECM) promotes chondrogenesis of MSCs. However, the role of MSCs stimulated by ECM is not well known in OA. The purpose of this study is to determine the role of specific factors generated by the application of ECM and umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) in managing OA symptoms. Cartilage acellular matrix (CAM), which is a cartilage-derived ECM, was used to promote the chondrogenesis of UCB-MSCs. Induced MSCs were analyzed using chondrogenic markers (aggrecan, collagen type 2, and SOX9) and bone morphogenic protein 6 (BMP6). BMP6 is known to be involved in early chondrogenesis of MSCs. As a result, treatment with CAM significantly increased the expression of chondrogenic markers and BMP6 in UCB-MSCs. Treatment with recombinant human BMP6 also dramatically increased the levels of chondrogenic markers in UCB-MSCs. In addition, UCB-MSCs and CAM were used to evaluate OA symptom improvement in a rabbit articular cruciate ligament transection (ACLT) model. Application of UCB-MSCs and CAM enhanced not only the structure and synthesis of proteoglycan and collagen type 2 but also anti-inflammatory effects in both rabbit joint and synovial fluid. Moreover, the detection of human cells and involvement of BMP6 were confirmed in rabbit cartilage tissues. This study indicates that therapeutic potential of UCB-MSCs with CAM is mediated via BMP6 in OA.

Wnt5a/Platelet-rich plasma synergistically inhibits IL-1β-induced inflammatory activity through NF-κB signaling pathway and prevents cartilage damage and promotes meniscus regeneration

Noncanonical Wnt5a is a particularly attractive growth factor to maintain chondrogenesis. Platelet-rich plasma (PRP) is an autologous blood-derived product and a source of bioactive growth factors involved in tissue regeneration. The present study aimed to investigate the effect and inflammation reaction of Wnt5a/PRP on meniscus cells, and evaluate meniscus regeneration and osteoarthritis (OA) prevention by the application of Wnt5a/PRP gel in a rabbit model of massive meniscal defect. In vitro, the proliferation, migration, differentiation, and interleukin-1 beta (IL-1β) IL-1β-induced inflammation reaction of meniscus cells treated by Wnt5a and PRP was assessed. In vivo, the anterior half of the medial meniscus of 18 New Zealand rabbits was excised and implanted with PRP gel, Wnt5a/PRP gel or untreated. After 6 and 12 weeks, the regenerated meniscus were evaluated. Wnt5a can promote the migration of meniscus cells. PRP and Wnt5a had synergistic effect in promoting the proliferation and chondrogenic differentiation of meniscus cells. The IL-1β-induced meniscus cells study showed that PRP and Wnt5a had the anti-inflammatory actions through nuclear factor kB (NF-κB) signaling pathway. PRP and Wnt5a/PRP significantly inhibited the increase of the p-p65/p65 and p-IκB-α/IκB-α ratios. In vivo transplantation of Wnt5a/PRP gel was demonstrated to promote meniscus regeneration, while reducing OA of knee joint. Wnt5a with PRP had the anti-inflammatory activity in an IL-1β-induced inflammatory model. They can synergistically improve the chondorgenic differentiation of meniscus cells. Wnt5a/PRP gel treatment could potentially be developed into a new method for meniscus regeneration and the prevention of OA.

Recombinant human bone morphogenetic protein-4 enhances tendon-to-bone attachment healing in a murine model of rotator cuff tear

Background

Injuries of tendon-to-bone attachments (TBA) are common clinical challenges. Bone morphogenetic protein-4 (BMP-4) is potent in chondrogenesis. However, studies focusing on the influence of BMP-4 on the healing of TBA are scarce. Thus, this study's objective was to explore the effect of BMP-4 on the healing of TBA in a murine model of rotator cuff tear.

Methods

An injury model of the supraspinatus tendon (SST) insertion was established on a total of 120 mature C57 black (BL)/6 mice (12 weeks old), who were then randomly allocated into 3 groups: BMP-4, noggin (an inhibitor of all BMP activities), and control, At weeks 2 and 4 after surgery, the supraspinatus tendon-humerus complexes (SSTHC) were harvested for microradiographic, histologic, immunofluorescent, and biomechanical evaluations.

Results

Radiographic data showed that BMP-4 was able to improve the quality of subchondral bone, manifested as higher bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), and lower trabecular spacing (Tb.Sp). Histologically, the BMP-4 group at week-2 and -4 showed a better TBA healing interface, characterized by better organizational integration and remodeling, thicker fibrocartilage layer, and more fibrocartilage cells. Immunofluorescence evaluation demonstrated that the number of SOX 9 positive cells in the BMP-4 group was significantly more than that in the control or noggin groups at postoperative weeks 2 and 4 (P<0.05 for all). Mechanical testing results at postoperative weeks 4 demonstrated the failure load, and stiffness in the BMP-4 group were significantly higher (P<0.05 for both), while in the noggin group were significantly lower (P<0.05 for both), compared to the control group.

Conclusions

The BMP-4 might enhance TBA healing by promoting the regeneration of fibrocartilaginous enthesis and mineralization, while this process was inhibited by noggin. Thus, BMP-4 may be a potential therapy to augment TBA healing and finally lead to more rapid rehabilitation and reduce recurrent injury risk.

Clinical therapy of platelet-rich plasma vs hyaluronic acid injections in patients with knee osteoarthritis: A systematic review and meta-analysis of randomized double-blind controlled trials

OBJECTIVE:

Knee osteoarthritis (KOA) is the most common degenerative disease of the joints caused by articular cartilage injury, degeneration of joint edges and hyperplasia of subchondral bone. The purpose of this study is to investigate the efficacy and safety of clinical therapy of platelet-rich plasma vs hyaluronic acid injections in patients with KOA.

METHODS:

We systematically investigated Pubmed, Embase, and the Cochrane Library for all related articles published through May 2020. Any study was included that compared the effect of platelet-rich plasma (PRP) and hyaluronic acid (HA) in patients with KOA. The search terms included “platelet-rich plasma,” “PRP,” “hyaluronic acid,” “HA,” “knee,” “osteoarthritis,” “arthritis,” “KOA”. Review Manager 5.3 was used to analyze and calculate data regarding these outcome indicators.

RESULTS:

In this study, 1. Six randomized double-blind controlled trials were included, including 338 patients in the PRP group and 323 patients in the HA group. 2. Meta-analysis results showed that the Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC) Total Score was differed significantly between the PRP and HA groups at the 1, 6, 12 months follow-up (MD = 3.39, 95% CI: 2.85–3.92, P < .05). In a comparison of Physical function scores at the 12 months follow-up, PRP improved knee function scores more than HA (MD = 3.28; 95% CI: 2.13–4.43; P < .05). However, International Knee Documentation Committee (IKDC), Tegner Activity scores, EuroQol visual analogue scale (EQ-VAS), and Adverse Events (AEs) were all not significantly different (P > .05). 3. Results showed that compared with HA, PRP had significant advantages in relevant improving knee function and quality of life.

CONCLUSION:

In improving knee function and quality of life, PRP showed superiority over HA in long-term follow-up from well-designed double-blind trials, but a large number of high-quality multi-center studies are still needed to provide more sufficient evidence.

Evaluation of Allogeneic Bone-Marrow-Derived and Umbilical Cord Blood-Derived Mesenchymal Stem Cells to Prevent the Development of Osteoarthritis in An Equine Model

Osteoarthritis (OA) is a significant cause of pain in both humans and horses with a high socio-economic impact. The horse is recognized as a pertinent model for human OA. In both species, regenerative therapy with allogeneic mesenchymal stem cells (MSCs) appears to be a promising treatment but, to date, no in vivo studies have attempted to compare the effects of different cell sources on the same individuals. The objective of this study is to evaluate the ability of a single blinded intra-articular injection of allogeneic bone-marrow (BM) derived MSCs and umbilical cord blood (UCB) derived MSC to limit the development of OA-associated pathological changes compared to placebo in a post-traumatic OA model applied to all four fetlock joints of eight horses. The effect of the tissue source (BM vs. UCB) is also assessed on the same individuals. Observations were carried out using clinical, radiographic, ultrasonographic, and magnetic resonance imaging methods as well as biochemical analysis of synovial fluid and postmortem microscopic and macroscopic evaluations of the joints until Week 12. A significant reduction in the progression of OA-associated changes measured with imaging techniques, especially radiography, was observed after injection of bone-marrow derived mesenchymal stem cells (BM-MSCs) compared to contralateral placebo injections. These results indicate that allogeneic BM-MSCs are a promising treatment for OA in horses and reinforce the importance of continuing research to validate these results and find innovative strategies that will optimize the therapeutic potential of these cells. However, they should be considered with caution given the low number of units per group.

Administration of mesenchymal stem cells from adipose tissue at the hip joint of dogs with osteoarthritis: A systematic review

This systematic review aimed to determine the effects of intra-articular administration of mesenchymal stem cells from adipose tissue in dogs with hip joint osteoarthritis (OA). Clinical trials were systematically reviewed, using PubMed, EMBASE, Cochrane Library, LILACS, Web of Science, Scopus, Open Grey, Google Scholar, and ProQuest Dissertation and Thesis without publication year restrictions. References were screened and selected based on predefined eligibility criteria by two independent reviewers, according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Clinical outcomes were assessed quantitatively using clinical pain scores, physical examination, imaging examination, questionnaire responses, pain in manipulation, gait analysis, range of joint motion, and adverse effects. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist. Out of 1483 articles, six met the inclusion criteria for qualitative analysis, with two randomized controlled trials and four before-and-after studies. All studies reported significantly better clinical outcomes in the adipose tissue stem cells (ADSC) group with improvements in pain and function and decreased evidence of hip OA. The risk of bias was categorized as high in the before-and-after studies and moderate to high in the randomized studies. The studies were considered heterogeneous owing to clinical results and methodology. Because of this heterogeneity, it was not possible to perform meta-analysis. Assessments of ADSC reports yielded positive clinical effects that showed improvements in pain and function and decreased evidence of hip osteoarthritis. More high-level, larger-cohort dog studies that utilize standardized protocols are needed.

Mesenchymal stem cell therapy combined with arthroscopic abrasion arthroplasty regenerates cartilage in patients with severe knee osteoarthritis: a case series

Aim: To evaluate the safety and efficacy of adipose-derived mesenchymal stem cell (ADMSC) therapy in combination with arthroscopic abrasion arthroplasty (AAA) in advanced knee osteoarthritis (OA). Materials & methods: 27 patients with Grade IV OA of the knee underwent AAA and ADMSC therapy (50 × 10⁶ ADMSCs at baseline and 6 months). Clinical outcome was assessed over 36 months. Structural change was determined using MRI. Results: Treatment was well tolerated with no serious adverse events. Clinically significant improvements in pain and function were observed. Reproducible hyaline-like cartilage regeneration was seen in all participants. Conclusion: ADMSC therapy combined with AAA in Grade IV OA results in reproducible pain, functional and structural improvements. This represents a joint preservation technique for patients with advanced OA of the knee. Trial registration number: ACTRN12617000638336.

Biologics

Biologics are a growing field that has shown immense promise for the treatment of musculoskeletal conditions both in orthopedic sports medicine and interventional pain management. These procedures utilize injection of supraphysiologic levels of platelets and growth factors to invoke the body's own inflammatory cascade to augment the healing of many bony and soft tissue conditions. While many patients improve with conservative care, there is a need to address the gap between those that improve with rehabilitation alone and those who ultimately require operative management. Orthobiologic procedures have the potential to fill this void. The purpose of this review is to summarize the basic science, evidence for use, and post-injection rehabilitation concepts of platelet-rich plasma (PRP) and mesenchymal stromal cells (MSCs) as they pertain to joints, tendons, ligaments, and the spine.

Mesenchymal stem cells - a promising strategy for treating knee osteoarthritis

AIMS

The purpose of our study was to determine whether mesenchymal stem cells (MSCs) are an effective and safe therapeutic agent for the treatment of knee osteoarthritis (OA), owing to their cartilage regeneration potential.

METHODS

We searched PubMed, Embase, and the Cochrane Library, with keywords including "knee osteoarthritis" and "mesenchymal stem cells", up to June 2019. We selected randomized controlled trials (RCTs) that explored the use of MSCs to treat knee OA. The visual analogue scale (VAS), Western Ontario and McMaster University Osteoarthritis Index (WOMAC), adverse events, and the whole-organ MRI score (WORMS) were used as the primary evaluation tools in the studies. Our meta-analysis included a subgroup analysis of cell dose and cell source.

RESULTS

Seven trials evaluating 256 patients were included in the meta-analysis. MSC treatment significantly improved the VAS (mean difference (MD), -13.24; 95% confidence intervals (CIs) -23.28 to -3.20, p = 0.010) and WOMAC (MD, -7.22; 95% CI -12.97 to -1.47, p = 0.010). The low-dose group with less than 30 million cells showed lower p-values for both the VAS and WOMAC. Adipose and umbilical cord-derived stem cells also had lower p-values for pain scores than those derived from bone marrow.

CONCLUSION

Overall, MSC-based cell therapy is a relatively safe treatment that holds great potential for OA, evidenced by a positive effect on pain and knee function. Using low-dose (25 million) and adipose-derived stem cells is likely to achieve better results, but further research is needed. Cite this article: Bone Joint Res 2020;9(10):719-728.

Degenerative osteoarthritis a reversible chronic disease

Osteoarthritis (OA) is the most common chronic musculoskeletal disorder. It can affect any joint and is the most frequent single cause of disability in older adults.

OA is a progressive degenerative disease involving the entire joint structure in a vicious circle that includes the capsule-bursa tissue inflammation, synovial fluid modifications, cartilage breakdown and erosions, osteochondral inflammatory damage leading to bone erosion and distortion.

Research has identified the initial inflammatory-immunologic process that starts this vicious cycle leading to so-called early OA. Research has also identified the role played in the disease advancement by synoviocytes type A and B, chondrocytes, extracellular matrix, local immune-inflammatory mediators and proteases.

This article investigates the joint-resident MSCs that play an essential local homeostatic role and regulate cell turn over and tissue repair. Resident MSCs establish and maintain a local regenerative microenvironment.

The understanding of OA physiopathology clarifies the core mechanisms by which minimally invasive interventions might be able to halt and reverse the course of early stage OA. Interventions employing PRP, MSCs and exosomes are considered in this article.

Evaluation of autologous adipose-derived mesenchymal stem cell therapy in focal chondral defects of the knee: a pilot case series

Aim: To evaluate the safety, pain, functional and structural improvements after autologous adipose-derived mesenchymal stem cell (ADMSC) therapy in combination with arthroscopic abrasion arthroplasty in focal chondral defects of the knee. Methods: Eight patients with a focal full thickness chondral defect of the knee underwent arthroscopic abrasion arthroplasty followed by postoperative intra-articular injections of autologous ADMSCs (50 × 10⁶ ADMSCs at baseline and 6 months). Clinical outcome was assessed using numeric pain rating scale, Knee Injury and Osteoarthritis Outcome Score and the Western Ontario and McMaster Universities Osteoarthritis Index. Structural outcome was determined by magnetic resonance imaging. Outcome was assessed over 24 months. Results: No serious adverse events occurred. Participants observed clinically significant improvement in pain and function. Magnetic resonance imaging analysis showed cartilage regeneration with T2 mapping values comparable to hyaline cartilage. Conclusion: Arthroscopic abrasion arthroplasty in combination with intra-articular ADMSC therapy results in reproducible pain, functional and structural improvements with regeneration of hyaline-like cartilage. Trial registration number: ACTRN12617000638336.

Effect of autologous adipose-derived mesenchymal stem cell therapy in the treatment of an osteochondral lesion of the ankle

Osteochondral lesions (OCLs) of the talus are rare but can be associated with significant morbidity and may lead to the development of osteoarthritis. An improved understanding of the action of mesenchymal stem cells (MSCs) has seen renewed interest in their role in cartilage repair, with early preclinical and clinical research showing benefits in symptomatic and structural improvement. A 42-year-old man presented with an unstable OCL of the talus and onset of early osteoarthritis with a history of multiple previous ankle arthroscopies for ankle impingement. The patient underwent arthroscopic removal of the OCL in combination with adipose-derived MSC therapy. The patient reported progressive improvement as measured by the validated Foot and Ankle Disability Index. Repeat MRI with additional T2 mapping techniques showed successful regeneration of hyaline-like cartilage. This case is the first to show the successful use of MSC therapy in the management of an ankle OCL. Trial registration: Australian New Zealand Clinical Trials Registry - ACTRN12617000638336.

IVD progenitor cells: a new horizon for understanding disc homeostasis and repair

Intervertebral disc (IVD) degeneration is associated with low back pain. In IVDs, a high mechanical load, high osmotic pressure and hypoxic conditions create a hostile microenvironment for resident cells. How IVD homeostasis and function are maintained under stress remains to be understood; however, several research groups have reported isolating native endogenous progenitor-like or otherwise proliferative cells from the IVD. The isolation of such cells implies that the IVD might contain a quiescent progenitor-like population that could be activated for IVD repair and regeneration. Increased understanding of endogenous disc progenitor cells will improve our knowledge of IVD homeostasis and, when combined with tissue engineering techniques, might hold promise for future therapeutic applications. In this Review, the characteristics of progenitor cells in different IVD compartments are discussed, as well as the potency of different cell populations within the IVD. The stem cell characteristics of these cells are also compared with those of mesenchymal stromal cells. On the basis of existing evidence, whether and how IVD degeneration and the hostile microenvironment might affect endogenous progenitor cell function are considered, and ways to channel the potential of these cells for IVD repair are suggested.

Platelet-Rich Products and Their Application to Osteoarthritis

Autologous platelet-rich plasma (PRP) is a biological preparation made from the patient's own plasma that contains a platelet concentration above the whole blood baseline. Owing to the release of growth factors and other cytokines after degranulation, platelets have a central role in inflammation and in different stages of the healing process. For this reason, PRP-derived products have been used to enhance healing of musculoskeletal injuries and modulate progression of inflammatory processes, including osteoarthritis (OA). Osteoarthritis is one of the main causes of musculoskeletal disabilities in horses, and currently, there is no effective treatment for this disease. Treatments that focus on the modulation of inflammation and disease progression offer new hope for OA. Platelet-rich plasma provides a more practical and accessible option of therapy compared to other forms of biological treatment (i.e., stem cell therapies) and is believed to induce the production of functional matrix. However, several factors related to PRP production, including methods of preparation and application, and intraindividual variability, lead to an inconsistent product, precluding reliable conclusions about its efficacy for clinical use. The aim of this study was to review the benefits related to the clinical use of PRP in OA as well as factors that influence its use, the limitations of this treatment, and future directions of PRP research and therapy.

Use of intraarticular injections of platelet-rich plasma in the treatment of knee osteoarthritis: A review article

Osteoarthritis is one of the most common degenerative conditions affecting knee joint. As our understanding in the disease pathogenesis is evolving, so do the treatment modalities. One of the postulated mechanisms suggests the production of inflammatory cytokines secondary to repeated micro trauma than in turn lead to cartilage damage overtime. Cartilage being avascular structure has limited potential for repair. Based on this, recent studies have been focusing on stimulating cartilage-healing process by growth factors. This is where platelet-rich plasma comes in to light. Literature is showing promising results of platelet-rich plasma in treating knee osteoarthritis. In this review we have discussed the preparation, composition, classification, uses of platelet-rich plasma as well as evidence for its efficacy and complications.

Significantly dysregulated genes in osteoarthritic labrum cells identified through gene expression profiling

The aim of the present study was to explore the molecular basis and identify significant genetic alterations in acetabular labrum cells associated with osteoarthritis (OA). Gene expression data of osteoarthritic and normal human labrum cells were downloaded from a public database and reanalyzed. Significant differentially expressed genes (DEGs) were acquired by performing a thorough analysis of microarray data between the OA acetabular labrum cells and control cells. Key genes in OA labrum cells were revealed by a combination of weighted gene co-expression network analysis (WGCNA) and protein-protein interaction (PPI) analysis. Literature mining and drug screening were further performed for these key genes. In total, 141 DEGs between OA and normal labrum cells were identified. In addition, WGCNA and PPI analysis identified 23 DEGs as key genes in the OA labrum. All the key genes were significantly downregulated in OA labrum cells and were grouped into two different WGCNA-PPI common subnetworks. Kinase insert domain receptor (KDR), CD34, cadherin 5 (CDH5), Fms related tyrosine kinase 1 (FLT1) and asporin were hub nodes in the PPI network of DEGs. These key genes were significantly enriched in functional clusters of transforming growth factor, alkaline phosphatase, bone morphogenic protein and extracellular matrix. Drug screening analysis identified several drugs targeting the key genes, including arachidonic acid, yohimbic acid and mimosine. The results of the present study indicate that the changes of FLT1, KDR, CD34 and CDH5 in acetabular labrum cells may be involved in the pathogenesis of OA and could serve as biomarkers and therapeutic targets of OA. Additionally, arachidonic acid, yohimbic acid and mimosine may act as potential drugs for OA.

Chondrogenic effect of liquid and gelled platelet lysate on canine adipose-derived mesenchymal stromal cells

Osteoarthritis associated with hip dysplasia is one of the most common orthopedic abnormalities in dogs, with an incidence of up to 40% in some breeds. Tissue therapy of cartilage has received great attention, with use of mesenchymal stromal cells and different types of biomaterials. The present study aimed to evaluate the effect of platelet lysate (PL) on the proliferation and differentiation of canine adipose tissue-derived mesenchymal stromal cells (ASCs), in liquid culture or hydrogels. PL was prepared from blood collected from healthy dogs and submitted to freezing-thawing cycles, and hydrogel was formed with canine thrombin. The effect of PL on the proliferation and differentiation of canine ASCs was evaluated in liquid and hydrogel systems, with microscopy, quantification of dsDNA, histology and quantification of glycosaminoglycans. The addition of 5% or 10% PL to the culture medium induced a greater proliferation rate than the presence of 10% fetal bovine serum. The cultivation of ASCs in PL gel, with normal or chondrogenic medium, resulted in maintenance of proliferation level similar to the conventional 2D cultivation, and induction of chondrogenic differentiation, especially in the presence of the chondrogenesis induction medium.

Concentration of Chondrogenic Soluble Factors in Freshly Harvested Lipoaspirate

BACKGROUND

Cartilage tissue has a limited capacity for healing with the consequence that patients are often treated symptomatically until they become candidates for osteotomy or total joint replacement. Alternative biological therapies, for example, application of platelet-rich plasma and implantation of chondrocytes and mesenchymal stem cells, have emerged as a new treatment modality to repair articular cartilage. In addition, autologous fat transfer is performed for treatment of cartilage defects, example given, in osteoarthrosis, but several questions regarding basic biochemical properties of the transplant remain unanswered. Bone morphogenetic protein 4 (BMP4), matrix metalloproteinase (MMP)-8, cartilage oligomeric matrix protein (COMP), and chitinase-3-like protein 1 (CHI3L1) have been shown to be involved in chondrogenic regeneration and represent potential therapeutic agents for cartilage repair. However, no study regarding naturally occurring levels of these soluble factors in transplanted adipose tissue has yet been performed.

METHODS

To investigate the influence of age, body mass index, donor site, and sex on the concentration of BMP4, MMP-8, COMP, and CHI3L1 in freshly aspirated adipose tissue, their content was measured by means of enzyme-linked immunosorbent assay readings.

RESULTS

There were significant quantities of BMP4, MMP-8, COMP, and CHI3L1 (23.6, 249.9, 298.0, and 540.6 pg/mg, respectively) in the lipoaspirate harvested for transplantation. There was no correlation between the content of soluble factors and the patients' age or body mass index. Furthermore, the sex did not affect the amount of the investigated factors. However, there were significantly lower contents of BMP4, COMP, and CHI3L1 found in lipoaspirates harvested from the abdomen compared with nonabdominal donor sites.

CONCLUSIONS

Naturally occurring differences in the concentrations of the investigated soluble factors will favor certain donor sites for autologous fat transfer in the field of cartilage repair. Thus, increasing knowledge will enable researchers and clinicians to make autologous fat transfer procedures more reliable and efficient for treatment of articular cartilage defects.

The use of PRP injections in the management of knee osteoarthritis

Osteoarthritis (OA) is a degenerative disease involving joint damage, an inadequate healing response and progressive deterioration of the joint architecture that commonly affects the knee and/or hip joints. It is a major world public health problem and is predicted to increase rapidly with an ageing population and escalating rate of obesity. Autologous blood-derived products possess much promise in the repair and regeneration of tissue and have important roles in inflammation, angiogenesis, cell migration and metabolism in pathological conditions, including OA. Utilising platelet-rich plasma (PRP) to treat tendon, ligament and skeletal muscle has shown variable results across many studies with the current evidence base for the efficacy of PRP in treating sports injuries remaining inconclusive. More uniformly positive results have been observed by various studies for PRP in OA knee in comparison to hyaluronic acid, other intra-articular injections and placebo than in other musculoskeletal tissue. However, methodological concerns as well as satisfactory PRP product classification prevent the true characterisation of this treatment. Thus, further research is required to investigate how leukocyte inclusion, activation and platelet concentration affect therapeutic efficacy. Furthermore, the optimisation of timing, dosage, volume, frequency and rehabilitation strategies need to be ascertained. For knee OA management, these concerns must be addressed before this promising treatment can be widely implemented.

High tibial osteotomy in combination with arthroscopic abrasion arthroplasty and autologous adipose-derived mesenchymal stem cell therapy in the treatment of advanced knee osteoarthritis

Osteoarthritis is a progressive and debilitating condition. An increasing number of total knee replacements are being performed under the age of 65. Improved understanding of the action of mesenchymal stem cells (MSC) has seen renewed interest in their role in cartilage repair. A 43-year-old man presented with grade IV medial compartment knee osteoarthritis. The patient underwent high tibial osteotomy (HTO) and arthroscopic abrasion arthroplasty in combination with adipose-derived MSC therapy. The patient reported improvement in pain and function as measured by validated outcome scores. Repeat MRI including T2 mapping techniques showed hyaline-like cartilage regeneration. This case highlights the potential benefit of surgical interventions including HTO in combination with MSC therapy in early-onset severe osteoarthritis. This technique may considerably delay or prevent the need for total knee replacement in young patients. Further controlled trials are needed to confirm the reproducibility of this outcome.

In vitro and in vivo potentialities for cartilage repair from human advanced knee osteoarthritis synovial fluid-derived mesenchymal stem cells

Background

Mesenchymal stem cells (MSCs) are found in synovial fluid (SF) and can easily be harvested during arthrocentesis or arthroscopy. However, SF-MSC characterization and chondrogenicity in collagen sponges have been poorly documented as well as their hypothetical in vivo chondroprotective properties with intra-articular injections during experimental osteoarthritis (OA).

Methods

SF-MSCs were isolated from human SF aspirates in patients suffering from advanced OA undergoing total knee joint replacements. SF-MSCs at passage 2 (P2) were characterized by flow cytometry for epitope profiling. SF-MSCs at P2 were subsequently cultured in vitro to assess their multilineage potentials. To assess their chondrogenicity, SF-MSCs at P4 were seeded in collagen sponges for 4 weeks under various oxygen tensions and growth factors combinations to estimate their gene profile and matrix production. Also, SF-MSCs were injected into the joints in a nude rat anterior cruciate ligament transection (ACLT) to macroscopically and histologically assess their possible chondroprotective properties,.

Results

We characterized the stemness (CD73+, CD90+, CD105+, CD34−, CD45−) and demonstrated the multilineage potency of SF-MSCs in vitro. Furthermore, the chondrogenic induction (TGF-ß1 ± BMP-2) of these SF-MSCs in collagen sponges demonstrated a good capacity of chondrogenic gene induction and extracellular matrix synthesis. Surprisingly, hypoxia did not enhance matrix synthesis, although it boosted chondrogenic gene expression (ACAN, SOX9, COL2A1). Besides, intra-articular injections of xenogenic SF-MSCs did exert neither chondroprotection nor inflammation in ACLT-induced OA in the rat knee.

Conclusions

Advanced OA SF-MSCs seem better candidates for cell-based constructs conceived for cartilage defects rather than intra-articular injections for diffuse OA.

Intra-articular injections of expanded mesenchymal stem cells with and without addition of platelet-rich plasma are safe and effective for knee osteoarthritis

PURPOSE

To compare the effectiveness and safety of intra-articular injections of autologous expanded mesenchymal stromal stem cells alone (MSCs), or in combination with platelet-rich plasma (MSCs + PRP), in patients with knee osteoarthritis.

METHODS

Eighteen patients (57.6 ± 9.6 years) with radiographic symptomatic knee osteoarthritis (Dejour grades II-IV) were randomized to receive intra-articular injections of MSCs (n = 9) or MSCs + PRP (n = 9). Injections were performed 2-3 weeks after bone marrow aspiration (± 80-100 ml) which was obtained from both posterior iliac crests.

RESULTS

The Knee Injury and Osteoarthritis Outcome Score (KOOS) improved significantly throughout the 12 months for both groups (p < 0.05). No statistically significant differences between groups were found in KOOS subscales and global score improvements at 12-month end-point (n.s.). The MSCs group showed significant improvements in the pain, function and daily living activities, and sports and recreational activities subscales (p < 0.05). Similarly, the MSCs + PRP group showed significant improvements in the pain, function and daily living activities and quality of life subscales (p < 0.05). The average number of fibroblast colony forming units (CFU-F) was 56.8 + 21.9 for MSCs group and 50.7 ± 21.7 for MSCs + PRP group. Minimal adverse effects were seen in both groups (10 adverse events, in 5 patients).

CONCLUSIONS

Intra-articular injections of expanded MSCs alone or in combination with PRP are safe and have a beneficial effect on symptoms in patients with symptomatic knee osteoarthritis. Adding PRP to the MSCs injections did not provide additional benefit. These results are encouraging and support the recommendation of this minimally invasive procedure in patients with knee osteoarthritis, without requiring hospitalization. The CFU-F results may be used as reference for future research.

LEVEL OF EVIDENCE

Prospective cohort study, Level II.

Injectable Systems for Intra-Articular Delivery of Mesenchymal Stromal Cells for Cartilage Treatment: A Systematic Review of Preclinical and Clinical Evidence

Stem cell-based therapy is a promising approach to treat cartilage lesions and clinical benefits have been reported in a number of studies. However, the efficacy of cell injection procedures may be impaired by cell manipulation and damage as well as by cell dissemination to non-target tissues. To overcome such issues, mesenchymal stromal cell (MSC) delivery may be performed using injectable vehicles as containment systems that further provide a favorable cell microenvironment. The aim of this systematic review was to analyze the preclinical and clinical literature on platelet-rich plasma (PRP), hyaluronic acid (HA), and hydrogels for the delivery of MSCs. The systematic literature search was performed using the PubMed and Web of science databases with the following string: "(stem cells injection) AND (platelet rich plasma OR PRP OR platelet concentrate OR biomaterials OR hyaluronic acid OR hydrogels)": 40 studies (19 preclinical and 21 clinical) met the inclusion criteria. This review revealed an increasing interest on the use of injectable agents for MSC delivery. However, while negligible adverse events and promising clinical outcomes were generally reported, the prevalence of low quality studies hinders the possibility to demonstrate the real benefits of using such injectable systems. Specific studies must be designed to clearly demonstrate the added benefits of these systems to deliver MSCs for the treatment of cartilage lesions and osteoarthritis.

Injectable Systems for Intra-Articular Delivery of Mesenchymal Stromal Cells for Cartilage Treatment: A Systematic Review of Preclinical and Clinical Evidence

Stem cell-based therapy is a promising approach to treat cartilage lesions and clinical benefits have been reported in a number of studies. However, the efficacy of cell injection procedures may be impaired by cell manipulation and damage as well as by cell dissemination to non-target tissues. To overcome such issues, mesenchymal stromal cell (MSC) delivery may be performed using injectable vehicles as containment systems that further provide a favorable cell microenvironment. The aim of this systematic review was to analyze the preclinical and clinical literature on platelet-rich plasma (PRP), hyaluronic acid (HA), and hydrogels for the delivery of MSCs. The systematic literature search was performed using the PubMed and Web of science databases with the following string: "(stem cells injection) AND (platelet rich plasma OR PRP OR platelet concentrate OR biomaterials OR hyaluronic acid OR hydrogels)": 40 studies (19 preclinical and 21 clinical) met the inclusion criteria. This review revealed an increasing interest on the use of injectable agents for MSC delivery. However, while negligible adverse events and promising clinical outcomes were generally reported, the prevalence of low quality studies hinders the possibility to demonstrate the real benefits of using such injectable systems. Specific studies must be designed to clearly demonstrate the added benefits of these systems to deliver MSCs for the treatment of cartilage lesions and osteoarthritis.

Age-dependent differences in response to partial-thickness cartilage defects in a rat model as a measure to evaluate the efficacy of interventions for cartilage repair

The objectives of this study are (1) to examine age-dependent longitudinal differences in histological responses after creation of partial-thickness articular cartilage defects (PTCDs) in rats and to use this model (2) to objectively evaluate the effectiveness of interventions for cartilage repair. Linear PTCDs were created at a depth of 100 μm in the weight-bearing region of the medial femoral condyle in rats of different ages (3 weeks, 6 weeks, 10 weeks and 14 weeks). One day, one week, two weeks, four weeks and twelve weeks after PTCD generation, spontaneous healing was evaluated histologically and immunohistochemically. Effects of interventions comprising mesenchymal stem cells (MSCs) or platelet-rich plasma (PRP) or both on 14-week-old PTCD rats were evaluated and compared with natural courses in rats of other ages. Younger rats exhibited better cartilage repair. Cartilage in 3-week-old and 6-week-old rats exhibited nearly normal restoration after 4-12 weeks. Cartilage in 14-week-old rats deteriorated over time and early signs of cartilage degeneration were observed. With injection of MCSs alone or MSCs + PRP, 14-week-old PTCD rats showed almost the same reparative cartilage as 6-week-old rats. With injection of PRP, 14-week-old PTCD rats showed almost the same reparative cartilage as 10-week-old rats. This model will be of great use to objectively compare the effects of interventions for small cartilage lesions and may help to advance the development of disease-modifying osteoarthritis drugs.

Role of Intra-articular Platelet Rich Plasma in the Management of Osteoarthritis: A Review

Intra-articular injections are a minimally invasive option developed for the management of patients with joint degenerative conditions. These injections can involve the use of steroid preparations, hyaluronic acid, and blood products. Platelet-rich plasma (PRP) is a cost-effective management modality developed for patients with joint degenerative conditions and has provided promising outcomes. It provides nourishment to the chondrocytes through a rich supply of growth factors and cytokines. This article demonstrates the beneficial effects of PRP therapy in patients with osteoarthritis.

Platelet-Rich Plasma and Cartilage Repair

PURPOSE OF REVIEW

To assess the utilization and efficacy of platelet-rich plasma (PRP), for the treatment of articular cartilage injury, most commonly characterized by progressive pain and loss of joint function in the setting of osteoarthritis (OA).

RECENT FINDINGS

PRP modulates the inflammatory and catabolic environment through a locally applied concentrate of platelets, leukocytes, and growth factors. Clinically, PRP has been shown to be possibly a viable treatment adjuvant for a variety of inflammatory and degenerative conditions. Recent efforts have focused on optimizing delivery methods that enable platelets to slowly degranulate their biological constituents, which may promote healing and improve OA symptoms for a longer duration. There are various factors that affect the progression of OA within joints, including inhibition of inflammatory cytokines and altering the level of enzymatic expression. PRP therapy aims to mediate inflammatory and catabolic factors in a degenerative environment through the secretion of anti-inflammatory factors and chemotaxic effects. There are a growing number of studies that have demonstrated the clinical benefit of PRP for non-operative management of OA. Additional randomized controlled trials with long-term follow-up are needed in order to validate PRP's therapeutic efficacy in this setting. Additionally, continued basic research along with well-designed pre-clinical studies and reporting standards are necessary in order to clarify the effectiveness of PRP for cartilage repair and regeneration for future clinical applications.

Potential Usefulness of Losartan as an Antifibrotic Agent and Adjunct to Platelet-Rich Plasma Therapy to Improve Muscle Healing and Cartilage Repair and Prevent Adhesion Formation

Postoperative tissue fibrosis represents a major complication in orthopedics. Transforming growth factor beta 1 is a key molecule in the development of postoperative fibrosis. High concentrations of transforming growth factor beta 1 have also been implicated in various diseases. Agents that counteract the actions of transforming growth factor beta 1 have been investigated as potential antifibrotic medications and as adjunct treatment to platelet-rich plasma injections (increased amounts of transforming growth factor beta 1) to improve their effectiveness and/or safety profile. Losartan blocks transforming growth factor beta 1 action and has attracted special interest in orthopedic research that focuses on how to reduce the risk of postoperative fibrosis. [Orthopedics. 2018; 41(5):e591-e597.].

Lateral meniscus allograft transplantation with platelet-rich plasma injections: A minimum two-year follow-up study

BACKGROUND

The aim of this study was to report the short-term clinical and imaging outcomes of lateral meniscus allograft transplantations (LMAT) combined with intra-articular platelet-rich plasma (PRP) injection.

METHODS

Thirty-three patients who had undergone LMAT combined with intra-articular PRP injection were evaluated. The Lysholm, International Knee Documentation Committee (IKDC), Western Ontario and McMaster Universities Osteoarthritis Index, Tegner activity level scale and visual analog scale for pain scores were used to evaluate the outcomes. Magnetic resonance imaging scans were performed postoperatively to assess graft position and chondral degeneration/damage.

RESULTS

A total of 31 of the original 33 patients were evaluated over a mean follow-up period of 37.0months. Patients demonstrated statistically significant improvements in all scoring data from the pre-operative to two-year follow-up period. The mean postoperative extrusion was 1.59±1.20mm (range 0-3.9mm). There were no significant differences in the distribution of the grade of chondral damage between the pre-operative and two-year follow-up periods. Three patients (9.7%) showed no improvements or had lower evaluation scores. One patient underwent matrix-induced autologous chondrocyte implantation at one year after LMAT.

CONCLUSION

Lateral meniscus allograft transplantation combined with intra-articular PRP injection resulted in statistically significant improvements in all functions and pain scores, and clinical improvements in Tegner, IKDC, and Lysholm values during short-term follow-up. A further case-control study with a larger sample size and longer follow-up is required to obtain an overall assessment of the benefits of PRP on MAT patients. Level of evidence IV.