Safety, tolerability, clinical, and joint structural outcomes of a single intra-articular injection of allogeneic mesenchymal precursor cells in patients following anterior cruciate ligament reconstruction: a controlled double-blind randomised trial

Culture-expanded mesenchymal stromal cell therapy: does it work in knee osteoarthritis? A pathway to clinical success

Osteoarthritis (OA) is a degenerative multifactorial disease with concomitant structural, inflammatory, and metabolic changes that fluctuate in a temporal and patient-specific manner. This complexity has contributed to refractory responses to various treatments. MSCs have shown promise as multimodal therapeutics in mitigating OA symptoms and disease progression. Here, we evaluated 15 randomized controlled clinical trials (RCTs) and 11 nonrandomized RCTs using culture-expanded MSCs in the treatment of knee OA, and we found net positive effects of MSCs on mitigating pain and symptoms (improving function in 12/15 RCTs relative to baseline and in 11/15 RCTs relative to control groups at study endpoints) and on cartilage protection and/or repair (18/21 clinical studies). We examined MSC dose, tissue of origin, and autologous vs. allogeneic origins as well as patient clinical phenotype, endotype, age, sex and level of OA severity as key parameters in parsing MSC clinical effectiveness. The relatively small sample size of 610 patients limited the drawing of definitive conclusions. Nonetheless, we noted trends toward moderate to higher doses of MSCs in select OA patient clinical phenotypes mitigating pain and leading to structural improvements or cartilage preservation. Evidence from preclinical studies is supportive of MSC anti-inflammatory and immunomodulatory effects, but additional investigations on immunomodulatory, chondroprotective and other clinical mechanisms of action are needed. We hypothesize that MSC basal immunomodulatory "fitness" correlates with OA treatment efficacy, but this hypothesis needs to be validated in future studies. We conclude with a roadmap articulating the need to match an OA patient subset defined by molecular endotype and clinical phenotype with basally immunomodulatory "fit" or engineered-to-be-fit-for-OA MSCs in well-designed, data-intensive clinical trials to advance the field.

Post-traumatic osteoarthritis: epidemiology, pathogenesis, clinical picture, approaches to pharmacotherapy

Post-traumatic osteoarthritis (PTOA) is an inflammatory and degenerative disease that occurs as a result of the joint structures injury. It is a common pathology, accounting for approximately 12% of all cases of osteoarthritis (OA). PTOA often occurs in people of young productive age, progresses rapidly, causing chronic pain and increasing dysfunction. Individuals undergoing joint replacement for PTOA are, on average, 10 years younger than those with primary OA. The time interval from the moment of injury to the onset of typical PTOA radiological signs varies widely – from 1 year to 15–20 years.The main injuries that cause PTOA are intra-articular fractures, anterior cruciate ligament injuries, meniscus rupture and dislocation of the patella of the knee joint, joint dislocations with damage to the ligamentous apparatus of the ankle and shoulder joints.The pathogenesis of PTOA is determined by chronic inflammation accompanied by macrophage activation, hyperproduction of cytokines, primarily interleukin (IL) 1â, chemokines and growth factors, progressive destruction of joint tissue and degenerative changes (fibrosis, neoangiogenesis, osteophytosis).Pathogenetic treatment of PTOA, which would stop the progression of the disease, has not been developed. The possibility of using inhibitors of IL1â, IL6, inhibitors of tumor necrosis factor á, glucocorticoids, hyaluronic acid, autologous cell based therapy is under study. The control of pain and inflammation in PTOA requires the prescription of traditional drugs that are widely used in the practice of managing patients with primary OA. In particular, the use of symptomatic delayed-acting agents, such as the injectable form of chondroitin sulfate, seems to be appropriate.

Biologics, Stem Cells, Growth Factors, Platelet-Rich Plasma, Hemarthrosis, and Scaffolds May Enhance Anterior Cruciate Ligament Surgical Treatment

Biologics including mesenchymal stem cells (MSCs), growth factors, and platelet-rich plasma may enhance anterior cruciate ligament (ACL) reconstruction and even ACL primary repair. In addition, hemarthrosis after acute ACL injury represents a source of biologic factors. MSCs can differentiate into both fibroblasts and osteoblasts, potentially providing a transition between the ligament or graft and bone. MSCs also produce cytokines and growth factors necessary for cartilage, bone, ligament, and tendon regeneration. MSC sources including bone marrow, synovium, adipose tissue, ACL-remnant, patellar tendon, and umbilical cord. Also, scaffolds may represent a tool for ACL tissue engineering. A scaffold should be porous, which allows cell growth and flow of nutrients and waste, should be biocompatible, and might have mechanical properties that match the native ACL. Scaffolds have the potential to deliver bioactive molecules or stem cells. Synthetic and biologically derived scaffolds are widely available. ACL reconstruction with improved outcome, ACL repair, and ACL tissue engineering are promising goals. LEVEL OF EVIDENCE: Level V, expert opinion.

Advanced Gene Therapy Strategies for the Repair of ACL Injuries

The anterior cruciate ligament (ACL), the principal ligament for stabilization of the knee, is highly predisposed to injury in the human population. As a result of its poor intrinsic healing capacities, surgical intervention is generally necessary to repair ACL lesions, yet the outcomes are never fully satisfactory in terms of long-lasting, complete, and safe repair. Gene therapy, based on the transfer of therapeutic genetic sequences via a gene vector, is a potent tool to durably and adeptly enhance the processes of ACL repair and has been reported for its workability in various experimental models relevant to ACL injuries in vitro, in situ, and in vivo. As critical hurdles to the effective and safe translation of gene therapy for clinical applications still remain, including physiological barriers and host immune responses, biomaterial-guided gene therapy inspired by drug delivery systems has been further developed to protect and improve the classical procedures of gene transfer in the future treatment of ACL injuries in patients, as critically presented here.

Clinical and laboratory findings following transplantation of allogeneic adipose-derived mesenchymal stromal cells in knee osteoarthritis, a brief report

BACKGROUND

Mesenchymal stromal cells (MSCs) injection has been proposed as an innovative treatment for knee osteoarthritis (KOA). Since, allogeneic MSCs can be available as off-the-shelf products, they are preferable in regenerative medicine. Among different sources for MSCs, adipose-derived MSCs (AD-MSCs) appear to be more available.

METHODS

Three patients with KOA were enrolled in this study. A total number of 100 × 10⁶ AD-MSCs was injected intra-articularly, per affected knee. They were followed up for 6 months by the assessment of clinical outcomes, magnetic resonance imaging (MRI), and serum inflammatory biomarkers.

RESULTS

The primary outcome of this study was safety and feasibility of allogeneic AD-MSCs injection during the 6 months follow-up. Fortunately, no serious adverse events (SAEs) were reported. Assessment of secondary outcomes of visual analogue scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and knee osteoarthritis outcome score (KOOS) indicated improvement in all patients. Comparison between baseline and endpoint findings of MRI demonstrated a slight improvement in two patients. In addition, decrease in serum cartilage oligomeric matrix protein (COMP) and hyaluronic acid (HA) indicated the possibility of reduced cartilage degeneration. Moreover, quantification of serum interleukin-10 (IL-10) and interleukin-6 (IL-6) levels indicated that the host immune system immunomodulated after infusion of AD-MSCs.

CONCLUSION

Intra-articular injection of AD-MSCs is safe and could be effective in cartilage regeneration in KOA. Preliminary assessment after six-month follow-up suggests the potential efficacy of this intervention which would need to be confirmed in randomized controlled trials on a larger population.

TRIAL REGISTRATION

This study was registered in the Iranian registry of clinical trials (https://en.irct.ir/trial/46) in 24 April 2018 with identifier IRCT20080728001031N23.

Practical Considerations for Translating Mesenchymal Stromal Cell-Derived Extracellular Vesicles from Bench to Bed

Extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) have shown potential for the treatment of tendon and ligament injuries. This approach can eliminate the need to transplant live cells to the human body, thereby reducing issues related to the maintenance of cell viability and stability and potential erroneous differentiation of transplanted cells to bone or tumor. Despite these advantages, there are practical issues that need to be considered for successful clinical application of MSC-EV-based products in the treatment of tendon and ligament injuries. This review aims to discuss the general and tissue-specific considerations for manufacturing MSC-EVs for clinical translation. Specifically, we will discuss Good Manufacturing Practice (GMP)-compliant manufacturing and quality control (parent cell source, culture conditions, concentration method, quantity, identity, purity and impurities, sterility, potency, reproducibility, storage and formulation), as well as safety and efficacy issues. Special considerations for applying MSC-EVs, such as their compatibility with arthroscopy for the treatment of tendon and ligament injuries, are also highlighted.

Current State of Platelet-Rich Plasma and Cell-Based Therapies for the Treatment of Osteoarthritis and Tendon and Ligament Injuries

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Orthobiologics encompass numerous substances that are naturally found in the human body including platelet-rich plasma (PRP), isolated growth factors, and cell therapy approaches to theoretically optimize and improve the healing of cartilage, fractures, and injured muscles, tendons, and ligaments.

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PRP is an autologous derivative of whole blood generated by centrifugation and is perhaps the most widely used orthobiologic treatment modality. Despite a vast amount of literature on its use in osteoarthritis as well as in tendon and ligament pathology, clinical efficacy results remain mixed, partly as a result of insufficient reporting of experimental details or exact compositions of PRP formulations used.

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Mesenchymal stromal cells (MSCs) can be isolated from a variety of tissues, with the most common being bone marrow aspirate concentrate. Similar to PRP, clinical results in orthopaedics with MSCs have been highly variable, with the quality and concentration of MSCs being highly contingent on the site of procurement and the techniques of harvesting and preparation.

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Advances in novel orthobiologics, therapeutic targets, and customized orthobiologic therapy will undoubtedly continue to burgeon, with some early promising results from studies targeting fibrosis and senescence.

Cellular Augmentation of Anterior Cruciate Ligament Surgery Is Not Currently Evidence Based: A Systematic Review of Clinical Studies

PURPOSE

To perform a systematic review of clinical outcome studies exploring cellular augmentation of anterior cruciate ligament (ACL) surgery, including stem cell techniques.

METHODS

A systematic search was performed according to the Preferred Reporting Items of Systematic Reviews and Meta-analyses (PRISMA) guidelines using the Cochrane, PubMed, MEDLINE, SPORTDiscus, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) databases from 2000 to 2019. The inclusion criteria were clinical studies that reported on ACL surgery augmented with stem cells or cellular therapy and patient-reported outcome measures or graft healing. Risk of bias was assessed using the Cochrane risk-of-bias tool for randomized clinical trials, and nonrandomized trials were assessed using the Methodological Items for Non-randomized Studies (MINORS) tool. Methodologic assessment was performed according to the Modified Coleman Methodology Score.

RESULTS

Four studies were found: 2 randomized clinical trials, 1 cohort study with a matched historical control group, and 1 case series. The mean Modified Coleman Methodology Score in these studies was 59, and there was a low risk of bias in 1 study. One study reported outcomes of augmented ACL repair, and 3 studies reported the results of augmented ACL reconstruction. Cellular therapies varied and included concentrated bone marrow aspirate, collagenase/centrifuge processed adipose, and marrow stimulation combined with platelet-rich plasma, as well as cells cultured from allograft bone marrow aspirate. The concentrated bone marrow aspirate and adipose tissue study results did not support their use. The marrow stimulation technique combined with repair led to promising clinical results. The use of allograft cultured cells improved patient-reported outcomes and postoperative radiographic findings.

CONCLUSIONS

Augmentation of ACL surgery with cellular therapy is not supported by clinical evidence at this time.

LEVEL OF EVIDENCE

Level IV.

Methodological quality and risk of bias of systematic reviews and meta-analyses on stem cells for knee osteoarthritis: A cross-sectional survey

Clinical guidelines need high-quality studies to support clinical decision-making, in which the evidence often was collected from systematic reviews (SRs) and/or meta-analyses (MAs). At present, the methodological quality and risk of bias (RoB) of SRs/MAs on stem cell therapy for the treatment of knee osteoarthritis (KOA) has been poorly investigated. This study aims to strictly evaluate the methodological quality and RoB in SRs/MAs of stem cell therapy for KOA. Four electronic databases (PubMed, Embase, Cochrane Library, and Web of Science databases) were searched, from inception to October 5th, 2021. SRs/MAs involving randomized control trials (RCTs) or cohort studies on stem cell therapy for the treatment of KOA were included. The methodological quality and RoB were assessed using AMSTAR 2 and ROBIS tool respectively. In total, 22 SRs/MAs were included. According to the results obtained by AMSTAR 2 tool, all SRs/MAs were rated as "Critically low". Main methodological weaknesses were as follows: up to 81.82% did not meet protocol registration requirements, only 13.64% provided a list of excluded studies and justification, and 13.64% investigated and discussed the publication bias.. ROBIS-based RoB assessment showed that all the SRs/MAs were rated as "High". Besides, the lack of following the implementation of the PRISMA reporting guideline seems to reduce the methodological quality of the studies. The overall methodological quality of the SRs/MAs concerning the application of stem cell therapy in treating KOA is "Critically low", while the RoB is high. It is difficult to provide effective evidence for the formulation of guidelines for KOA treatment. We suggest that the relevant methodological quality assessment should be carried out in the future before the SRs/MAs are used as clinical evidence. In addition, it may be necessary for many journals to include the checklist with a submitted manuscript.

Bone Marrow Aspirate Concentrate Is Equivalent to Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis at 2 Years: A Prospective Randomized Trial

BACKGROUND

Autologous platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMC) are being used clinically as therapeutic agents for the treatment of knee osteoarthritis.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare the efficacy of BMC and PRP on pain and function in patients with knee osteoarthritis up to 24 months after injection. It was hypothesized that patients receiving BMC would have better sustained outcomes than those receiving PRP.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

A total of 90 participants aged between 18 and 80 years with symptomatic knee osteoarthritis (Kellgren-Lawrence grades 1-3) were randomized into 2 study groups: PRP and BMC. Both groups completed the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and subjective International Knee Documentation Committee (IKDC) questionnaire before and 1, 3, 6, 9, 12, 18, and 24 months after a single intra-articular injection of leukocyte-rich PRP or BMC. A linear mixed-effects model was performed to quantify the effects over time and the difference between the groups. This model has the random effect for time to assess the extent in which the change over time differs from one person to another.

RESULTS

An overall 84 patients completed questionnaires from baseline to 12 months; however, 17 patients (n = 9; PRP group) were lost to follow-up at 18 months and 25 (n = 13; PRP group) at 24 months. There were no statistically significant differences in IKDC (P = .909; 95% CI, -6.26 to 7.03) or WOMAC (P = .789; 95% CI, -6.26 to 4.77) scores over time between the groups. Both groups had significantly improved IKDC (P < .001; 95% CI, 0.275-0.596) and WOMAC (P = .001; 95% CI, -0.41 to -0.13) scores from baseline to 24 months after the injection. These improvements plateaued at 3 months and were sustained for 24 months after the injection, with no difference between PRP and BMC at any time point.

CONCLUSIONS

For the treatment of osteoarthritis, PRP and BMC performed similarly out to 24 months. BMC was not superior to PRP.

REGISTRATION

NCT03289416 (ClincalTrials.gov identifier).

Stem cells in tendon regeneration and factors governing tenogenesis

Tendons are connective tissue structures of paramount importance to the human ability of locomotion. Tendinopathy and tendon rupture can be resistant to treatment and often recurs, thus resulting in a significant health problem with a relevant social impact worldwide. Unfortunately, existing treatment approaches are suboptimal. A better understanding of the basic biology of tendons may provide a better way to solve these problems and promote tendon regeneration. Stem cells, either obtained from tendons or non-tendon sources, such as bone marrow (BMSCs), adipose tissue (AMSCs), as well as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), have received increasing attention toward enhancing tendon healing. There are many studies showing that stem cells can contribute to improving tendon healing. Hence, in this review, the current knowledge of BMSCs, AMSCs, TSPCs, ESCs and iPSCs for tendon regeneration, as well as the advantages and limitations among them, has been highlighted. Moreover, the transcriptional and bioactive factors governing tendon healing processes have been discussed.

Current trends in the anterior cruciate ligament part 1: biology and biomechanics

A trend within the orthopedic community is rejection of the belief that "one size fits all." Freddie Fu, among others, strived to individualize the treatment of anterior cruciate ligament (ACL) injuries based on the patient's anatomy. Further, during the last two decades, greater emphasis has been placed on improving the outcomes of ACL reconstruction (ACL-R). Accordingly, anatomic tunnel placement is paramount in preventing graft impingement and restoring knee kinematics. Additionally, identification and management of concomitant knee injuries help to re-establish knee kinematics and prevent lower outcomes and registry studies continue to determine which graft yields the best outcomes. The utilization of registry studies has provided several large-scale epidemiologic studies that have bolstered outcomes data, such as avoiding allografts in pediatric populations and incorporating extra-articular stabilizing procedures in younger athletes to prevent re-rupture. In describing the anatomic and biomechanical understanding of the ACL and the resulting improvements in terms of surgical reconstruction, the purpose of this article is to illustrate how basic science advancements have directly led to improvements in clinical outcomes for ACL-injured patients.Level of evidenceV.

Stem Cell Therapy and Its Significance in Pain Management

Pain management has always been a challenging issue, which is why it has been a major focus of many rigorous studies. Chronic pain which typically lasts for more than three months is prevalent at an astounding rate of 11% to 19% of the adult population. Pain management techniques have gone through major advances in the last decade with no major improvement in the quality of life in affected populations. Recently there has been growing interest in the utilization of stem cells for pain management. Advancement of stem cell therapy has been noted for the past few years and is now being used in human clinical trials. Stem cell therapy has shown promising results in the management of neuropathic, discogenic back, osteoarthritis, and musculoskeletal pain. In this article, we will discuss the role of stem cells in the pain management of the aforementioned conditions, along with the mechanism, adverse effects, and risks of stem cell therapy.

Application of Stem Cell Therapy for ACL Graft Regeneration

Graft regeneration after anterior cruciate ligament (ACL) reconstruction surgery is a complex three-stage process, which usually takes a long duration and often results in fibrous scar tissue formation that exerts a detrimental impact on the patients' prognosis. Hence, as a regeneration technique, stem cell transplantation has attracted increasing attention. Several different stem cell types have been utilized in animal experiments, and almost all of these have shown good capacity in improving tendon-bone regeneration. Various differentiation inducers have been widely applied together with stem cells to enhance specific lineage differentiation, such as recombinant gene transfection, growth factors, and biomaterials. Among the various different types of stem cells, bone marrow-derived mesenchymal stem cells (BMSCs) have been investigated the most, while ligament stem progenitor cells (LDSCs) have demonstrated the best potential in generating tendon/ligament lineage cells. In the clinic, 4 relevant completed trials have been reported, but only one trial with BMSCs showed improved outcomes, while 5 relevant trials are still in progress. This review describes the process of ACL graft regeneration after implantation and summarizes the current application of stem cells from bench to bedside, as well as discusses future perspectives in this field.

Alloreactive Immune Response Associated to Human Mesenchymal Stromal Cells Treatment: A Systematic Review

The well-known immunomodulatory and regenerative properties of mesenchymal stromal cells (MSCs) are the reason why they are being used for the treatment of many diseases. Because they are considered hypoimmunogenic, MSCs treatments are performed without considering histocompatibility barriers and without anticipating possible immune rejections. However, recent preclinical studies describe the generation of alloantibodies and the immune rejection of MSCs. This has led to an increasing number of clinical trials evaluating the immunological profile of patients after treatment with MSCs. The objective of this systematic review was to evaluate the generation of donor specific antibodies (DSA) after allogeneic MSC (allo-MSC) therapy and the impact on safety or tolerability. Data from 555 patients were included in the systematic review, 356 were treated with allo-MSC and the rest were treated with placebo or control drugs. A mean of 11.51% of allo-MSC-treated patients developed DSA. Specifically, 14.95% of these patients developed DSA and 6.33% of them developed cPRA. Neither the production of DSA after treatment nor the presence of DSA at baseline (presensitization) were correlated with safety and/or tolerability of the treatment. The number of doses administrated and human leucocyte antigen (HLA) mismatches between donor and recipient did not affect the production of DSA. The safety of allo-MSC therapy has been proved in all the studies and the generation of alloantibodies might not have clinical relevance. However, there are very few studies in the area. More studies with adequate designs are needed to confirm these results.

Mesenchymal stromal cell products for intra-articular knee injections for conservative management of osteoarthritis

Sports injuries and secondary joint problems, mainly of the knee, are common, especially in sports associated with high impact activities and/or torsional loading. The consequences can be career ending in elite athletes and reduce exercise activities in recreational people. Various cell products can be injected intra-articularly. First, fresh cellular mixtures can be prepared and injected in the same day, such as stromal vascular fraction of adipose tissue (SVF) and bone marrow concentrates (BMCs). Second, autologous mesenchymal stromal cells (MSCs) can be isolated from BMCs or SVF and, after several weeks of laboratory expansion, several millions of MSCs can be obtained for intra-articular injection. Finally, allogeneic MSCs from the bone marrow, adipose tissue or perinatal tissues of selected donors constitute an ‘off-the-shelf’ experimental treatment for injection delivery in patients with osteoarthritis of the knee. The perceived efficacy of all these products is based on the hypothesis of a paracrine mechanism of action: when living cells are delivered within the joint, they establish a molecular cross-talk with immune cells and local cell phenotypes, thereby modulating inflammation with subsequent modifications in the catabolic/degenerative milieu. Current clinical research examines whether injection delivery of MSCs translates into actual clinical benefits. Overall, clinical studies lack the quality needed to answer major research questions, including clinical and structural efficacy, optimal cell dose, and number of injections and specific protocol for cell delivery. Poor experimental designs are exacerbated by the diversity of patient phenotypes that hinder comparisons between treatments. Further understanding of disease pathology is paramount to develop potent function assays and understand whether the host tissue, the cell product or both should be primed before MSCs are injected intra-articularly.

Cell-based therapy in soft tissue sports injuries of the knee: a systematic review

INTRODUCTION

An ever-increasing number of clinics are offering purportedly 'regenerative' stem-cell treatments, although cell-based therapies may not primarily act as stem cells and have shown the ability to regenerate end-target tissues in some clinical studies only. We aim to systematically review the evidence for their use in soft-tissue sports injuries of the knee.

AREAS COVERED

A search for articles pertaining to the use of preparations of, or containing, mesenchymal stem cells (MSCs) in human subjects in sports knee injuries yielded 14 relevant results for inclusion after screening: 7 used cultured MSCs, 5 bone marrow concentrate (BMC), and the remaining 2 evaluated stromal vascular fraction (SVF) and tenocyte-like-cells. Most studies were level 3 or lower (n = 9).

EXPERT OPINION

There is insufficient high-quality evidence for the use of cell-based therapies that demonstrates either ligamentous or tendinous healing, meniscal volume restoration, or post-traumatic osteoarthritis amelioration/regression. Methods of cell harvesting, preparation, and application are highly heterogenous. Efforts should be directed toward standardization of protocols and their reporting, starting with more basic scientific investigations of MSCs and their niche, as well as rigorous, large clinical RCTs adhering to the reporting principles set out by recent expert consensus.

Clinical Applicability of Adult Human Mesenchymal Stem Cell Therapy in the Treatment of Knee Osteoarthritis

Introduction

Osteoarthritis causes a progressive deterioration to the protective cartilage between the joints leading to chronic pain and disability. This review focuses on the intrinsic potential of MSCs to stabilize and repair the cartilage tissue of the knee joint in knee osteoarthritis (KOA) patients.

Methods

An online search through the PubMed database was conducted, limiting the search to the English language and human clinical trials within the past 5 years. Twenty-one clinical trials passed the inclusion criteria. Combined, those trials involved the participation of 589 patients where the progress of the treatments was monitored between a 4-month to 7-years period. The cartilage volume and defects were observed through an MRI to provide an objective assessment. While the pain and knee function were monitored using KOOS, VAS, and WOMAC scoring scales providing a subjective assessment.

Results

MRI scans obtained from clinical trials demonstrate a slowed progression of cartilage degeneration and early signs of cartilage regeneration in KOA patients at the 12-month follow-up period. No major adverse effects were observed post-intervention. The overall KOOS, WOMAC, and VAS scores in patients receiving MSC treatment were reduced, suggesting subjective improvements in knee function and pain reduction when compared to patients in the placebo group.

Conclusion

The use of MSC therapy is a valid form of treatment for KOA as it targets the disease itself rather than the symptoms. We found MSC therapy in KOA patients to be safe, effective, and feasible in its execution.

Effect of Stem Cell Injections on Osteoarthritis-related Structural Outcomes: A Systematic Review

OBJECTIVE

To systematically review the evidence for the efficacy of mesenchymal stem cell (MSC) injections in improving osteoarthritis (OA)-related structural outcomes.

METHODS

Ovid Medline and EMBASE were searched from their inceptions to April 2020 using MeSH terms and key words. Independent reviewers extracted data and assessed methodological quality. Qualitative evidence synthesis was performed due to the heterogeneity of interventions and outcome measures.

RESULTS

Thirteen randomized controlled trials (phase I or II) were identified: 10 in OA populations and 3 in populations at risk of OA, with low (n = 9), moderate (n = 3), or high (n = 1) risk of bias. Seven studies used allogeneic MSCs (4 bone marrow, 1 umbilical cord, 1 placenta, 1 adipose tissue), 6 studies used autologous MSCs (3 adipose tissue, 2 bone marrow, 1 peripheral blood). Among the 11 studies examining cartilage outcomes, 10 found a benefit of MSCs on cartilage volume, morphology, quality, regeneration, and repair, assessed by magnetic resonance imaging, arthroscopy, or histology. The evidence for subchondral bone was consistent in all 3 studies in populations at risk of OA, showing beneficial effects. Sixteen unpublished, eligible trials were identified by searching trial registries, including 8 with actual or estimated completion dates before 2016.

CONCLUSION

Our systematic review of early-phase clinical trials demonstrated consistent evidence of a beneficial effect of intraarticular MSC injections on articular cartilage and subchondral bone. Due to the heterogeneity of MSCs, modest sample sizes, methodological limitations, and potential for publication bias, further work is needed before this therapy is recommended in the management of OA.

The perspectives of intra-articular therapy in the management of osteoarthritis

Management of Osteoarthritis (OA) still is a challenge for clinicians. Taking into account a multidisciplinary approach including pharmacological and non-pharmacological treatments, intra-articular (IA) injection could be considered as an effective local therapy. Areas covered This review provides a new perspective of IA treatment going beyond current available IA agents. We describe novel biological targets for developing new IA agents and innovative modalities of delivery systems. Additional topics include predictors of response for a better choice of IA agents for each patient, diagnostic and prognostic role of biomarkers, accuracy of IA injection, and cost-effectiveness of IA injection. Expert opinion IA treatments seem to be very promising for the management of OA. Identifying clinical and biochemical predictive factors could drive clinician to the appropriate therapeutic approach. To date, there is a gap regarding the benefit of IA treatments in the 'real practice' once they have been adopted. However, considering these promising effects of IA approach, several open questions remain not clarified.

Allo-antibody production after intraarticular administration of mesenchymal stem cells (MSCs) in an equine osteoarthritis model: effect of repeated administration, MSC inflammatory stimulation, and equine leukocyte antigen (ELA) compatibility

Background

Antibody production after allogeneic administration of mesenchymal stem cells (MSCs) could impact their clinical application. Proinflammatory priming of MSCs can potentiate their regulatory ability in vivo but increased expression of major histocompatibility complex (MHC) might augment their immunogenicity, potentially leading to immune memory thus limiting repeated allogeneic administration. This study aimed at evaluating the production of cytotoxic allo-antibodies directed against donor’s ELA (equine leukocyte antigen) in mismatched and halfmatched horses receiving repeated intraarticular administration of stimulated MSCs (MSC-primed) and unstimulated MSCs (MSC-naïve) in pathologic joints.

Methods

From available stored samples from a previous in vivo study, cells from one donor and serially collected sera (five time-points) from three groups of recipients were used based on their ELA haplotypes to perform microcytotoxicity assays: Group 1 recipients mismatched with the donor that received MSC-naïve (naïve-mismatched recipients); Group 2 recipients mismatched with the donor that received MSC-primed (primed-mismatched recipients); Group 3 recipients halfmatched with the donor (sharing 1/2 haplotypes) that received MSC-primed (primed-halfmatched recipients). Sera from recipients (neat, 1:2 and 1:16 dilution) were tested against target cells from the donor (cryopreserved and expanded MSC-naïve and MSC-primed) or from one animal presenting the same ELA haplotypes than the donor (fresh peripheral blood lymphocytes as control).

Results

One to three weeks after first MSC administration, all recipient groups produced allo-antibodies regardless of MSC received (naïve or primed) and matching degree with donor. However, secondary response after MSC re-exposure was less evident in halfmatched recipients (MSC-primed) than in mismatched ones (both MSC-naïve and MSC-primed). Recipients of MSC-primed (both mismatched and halfmatched) tended towards developing lower antibody response than MSC-naïve recipients in vivo, but MSC-primed were targeted to death in higher percentage in vitro in the microcytoxicity assay.

Conclusions

After first intraarticular allogeneic administration, the immunomodulatory profile of MSC-primed would have led to lower antibody production, but these antibodies would target more easily MSC-primed after second injection (re-exposure), likely because of their higher MHC expression.

Electronic supplementary material

The online version of this article (10.1186/s13287-020-1571-8) contains supplementary material, which is available to authorized users.

Mesenchymal Stem Cells for Treatment of Tendon and Ligament Injuries-clinical Evidence

Introduction

Sport injuries, most of the time affect muscles, tendons, ligaments, cartilage and bones and range from very mild to severe, prompting different therapeutic approaches. Overuse is the most common cause of sports injuries and half of those injuries affect tendon, tendon sheet and tendon insertion to the bone. The number of ligament injuries, particularly anterior cruciate ligament (ACL) increasing.

Aim

We were searching PubMed, Google Scholar and Medline focusing on human clinical studies related to stem cell therapy for tendinopathies and ligament injuries. Considering small number of published articles, we accepted papers with all level of evidence without following strict PRISMA guidelines.

Results

The number of studies related to ligament injuries is very low compared to tendon injuries. In human clinical trials there have been only a few studies published so far. In double blind randomized control trial (RCT) Wang and coauthors combined allogenic precursor mesenchymal stem cells (MPC) with hyaluronic acid (HA) and compared with hyaluronic acid alone in 17 patients underwent ACL reconstruction. Intensity of pain and quality of life were assessed by Knee Injury and Osteoarthritis Outcome Score (KOOS) and SF-36v2 scores. A width of joint space, volume of cartilage and bone were recorded by magnetic resonance imaging (MRI). Moderate arthralgia and swelling were detected within 24 hours after the injection in 4 out of 11 patients in the group receiving MSC+HA. In the group receiving only HA, there were no adverse reactions. The signs of slowing down of regenerative process were presented on MRI by preserving joint space and reducing degradation of cartilage volume.

Conclusion

Clinical application of MSCs for treatment of tendon and ligament injuries might be good alternative option for athletes. Published clinical studies confirmed clinical improvement and integrity of impaired tissues. However, RTCs are needed to confirm real potential of cell therapy and their advantages comparing to other treatment options.

Injections intra articulaires (IA) d'acide hyaluronique (AH) dans le traitement symptomatique de la gonarthrose : une méta-analyse des injections uniques (mono-injections)

Introduction

La viscosupplémentation du liquide synovial par injections intra articulaires (IA) d'acide hyaluronique (AH), est un traitement symptomatique bien connu dans la gonarthrose. La question se pose de savoir si les traitements par injection unique (mono-injection) peuvent présenter autant d'efficacité que les multi-injections (3 à 5).

Méthodes

Une méta-analyse des résultats publiés pour les essais de mono-injections IA de AH a été réalisée. Le critère d'efficacité retenu a été le sous-score douleur de l'indice Western Ontario and MacMaster universities (WOMAC A). Toutes les conceptions d'études ont été admises, depuis les essais randomisés contrôlés jusqu'aux études observationnelles ouvertes à simple bras. Une recherche extensive a été effectuée à partir de PubMed, Google, Google Scholar, et des listes de références trouvées dans les méta-analyses récentes, pour obtenir tous les articles publiés avant fin avril 2018. Les profils des populations furent analysés en termes d'âge, de sexe, d'indice de masse corporelle (IMC) et de stade radiologique selon Kellgren-Lawrence (KL). Les résultats d'injection IA unique de placebo, ont été pris en compte pour créer une base permettant des comparaisons post-hoc. Chaque bras AH IA étudié a été comparé à un bras placebo IA (seul ou mixé), de manière à présenter un profil KL similaire, contrôlé à l'aide du test Chi². Les tailles de l'effet (ES) avec intervalles de confiance (IC 95%) et p-valeurs furent calculées et synthétisées pour chacune des visites de contrôle à 1, 2, 3 et 6 mois. En parallèle, une approche globale a été utilisée afin de représenter les variations par rapport à la baseline, pour chacun des sous-groupes étudiés.

Résultats

En partant de 1 547 citations, 28 études ont été incluses dans la méta-analyse, décrivant 4 129 patients traités par mono-injection: 3 360 ont reçu de l'AH IA et 769 patients ont reçu du placebo IA. Le patient moyen (SD) traité par AH IA était âgé de 61,2 (9,6) ans dont 63% de femmes, avec un IMC de 28,0 (4,1) kg/m², et un stade radiologique à 47% KL III pour 3% KL IV. Un bon appariement du profil KL a été obtenu pour 26 des 31 bras AH IA. Sur l'ensemble de la population AH IA, ES = 0,30 (0,25; 0,35) à 3 mois et ES = 0,39 (0,33; 0,44) à 6 mois. Dans une analyse restreinte, après élimination des cas aberrants, des KL mal appariés et des bras actifs < 30 patients, les résultats sont restés inchangés, ES = 0,29 (0,23; 0,34) et ES = 0,40 (0,34; 0,45) à 3 et 6 mois respectivement, tandis que l'hétérogénéité était améliorée.

Discussion

Il existe certainement des limites à la méthode de comparaison post-hoc versus placebo, appliquée à des essais individuels. Mais pour chaque synthèse par sous-groupe ou groupe, les résultats ont été confirmés en utilisant plusieurs approches statistiques et différentes méthodes de pondération. Cette méta-analyse suggère que les résultats des mono-injections sont similaires à ceux des multi-injections d'acide hyaluronique intra articulaire en termes de soulagement de la douleur, dans le traitement de la gonarthrose.

Stem Cell Treatment for Ligament Repair and Reconstruction

PURPOSE OF REVIEW

With the rapid and ongoing evolution of regenerative and sports medicine, the use of stem/stromal cells in ligament repair and reconstruction continues to be investigated and grow. The purpose of this review was to assess available methods and formulations for stem/stromal cell augmentation as well as review early pre-clinical and clinical outcomes for these recently emerging techniques.

RECENT FINDINGS

Recent literature demonstrates promising outcomes of stem/stromal cell augmentation for ligament repair and reconstruction. Multiple groups have published animal models suggesting improved healing for partially transected ligaments as well as histologic re-approximation of native bone-tendon interfaces with the use of mesenchymal stem/stromal cells in reconstructive models. Human studies also suggest improved outcomes spanning from higher patient-reported outcome scores to magnetic resonance imaging evidence of ligament healing in the setting of anterior cruciate ligament tears. However, clinical studies are only recently available, relatively few in number, and not necessarily accompanied by standard-of-care controls. There is increasing availability and growing animal and clinical evidence demonstrating potential benefit of stem/stromal cell augmentation for tendon healing. However, to date, there is a relative paucity of high-level human evidence for the routine use of stem/stromal cells for ligament repair and reconstruction in the clinical practice. This field contains substantial promise and merits further, ongoing investigation.

Minimizing Posttraumatic Osteoarthritis After High-Energy Intra-Articular Fracture

This article serves to provide an overview of molecular and surgical interventions to minimize the progression of posttraumatic arthritis following high-energy intra-articular fractures. The roles of cartilage and the microcellular environment are discussed, as well as the response of the joint and cartilage to injury. Molecular therapies, such as glucocorticoids, mesenchymal stem cells, and bisphosphonates, are presented as potential treatments to prevent progression to posttraumatic arthritis. High-energy intra-articular fractures of the elbow, hip, knee, and ankle are discussed, with emphasis on restoring anatomic alignment, articular reduction, and stability of the joint.

Tendon-to-Bone Healing in a Rat Extra-articular Bone Tunnel Model: A Comparison of Fresh Autologous Bone Marrow and Bone Marrow-Derived Mesenchymal Stem Cells

BACKGROUND

Despite widespread acceptance of fresh autologous bone marrow (BM) for use in clinical practice, limited information exists to analyze if tendon-to-bone healing could be accelerated with local use of fresh autologous BM.

PURPOSE

To investigate the effect of fresh autologous BM on tendon-to-bone healing with a novel rat model.

STUDY DESIGN

Controlled laboratory study.

METHODS

An extra-articular bone tunnel was created and filled with an autologous tendon graft in skeletally mature Sprague-Dawley rats (N = 60). They were then randomly divided into 3 groups: BM group (injection of fresh autologous BM into the tendon-bone interface, n = 20), BM-derived mesenchymal stem cell (BMSC) group (injection of allogenic cultured BMSCs, n = 20), and the control group (tendon-bone interface without injection of BM or BMSCs, n = 20). Biomechanical, histological, and immunohistochemical analyses were performed at 2 and 6 weeks after surgery.

RESULTS

The BM group showed a relatively well-organized and dense connective tissue interface with better orientation of collagen fibers as compared with the BMSC group. At 2 weeks, the tendon-bone interface tissue thickness of the BMSC group was 140 ± 25 μm (mean ± SEM), which was significantly greater than the BM group (58 ± 15 μm). The BM group showed fewer M1 macrophages at the tendon-bone interface at 2 and 6 weeks (P < .001). In contrast, there were more M2 macrophages at the interface in the BM group 2 and 6 weeks postoperatively when compared with controls and the BMSC group (P < .001). Biomechanical tests revealed significantly higher stiffness in the BM group versus the control and BMSC groups at 2 and 6 weeks after surgery (P < .05). Load to failure showed similar trends to stiffness.

CONCLUSION

These findings indicate that local delivery of fresh autologous BM enhances tendon-to-bone healing better than the alternative treatments in this study. This effect may be partially due to the observed modulation of inflammatory processes, especially in M2 macrophage polarization.

CLINICAL RELEVANCE

Fresh autologous BM could be a treatment option for this disorder.

Timeline for Maximal Subjective Outcome Improvement After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Anterior cruciate ligament (ACL) tears are one of the most common traumatic knee injuries experienced by athletes. Return to sport is considered the pinnacle endpoint among patients receiving ACL reconstruction. However, at the time of return to sport, patients may not be participating at their previous levels of function, as defined by clinical metrics.

PURPOSE

To establish when patients perceive maximal subjective medical improvement according to patient-reported outcome measures (PROMs).

STUDY DESIGN

Systematic review.

METHODS

A systematic review of the PubMed database was conducted to identify studies that reported sequential PROMs up to a minimum of 2 years after ACL reconstruction. Pooled analysis was conducted for PROMs at follow-up points of 3 months, 6 months, 1 year, and 2 years. Clinically significant improvement was determined between pairs of intervals with the minimal clinically important difference.

RESULTS

This review contains 30 studies including 2253 patients who underwent ACL reconstruction. Clinically significant improvement in the KOOS (Knee injury and Osteoarthritis Outcome Score) was seen up to 1 year after ACL reconstruction, but no clinical significance was noted from 1 to 2 years. Clinically significant improvement in the IKDC (International Knee Documentation Committee) and Lysholm questionnaires was seen up to 6 months postoperatively, but no clinical significance was noted beyond that.

CONCLUSION

After ACL reconstruction, maximal subjective medical improvement is established 1 year postoperatively, with no further perceived clinical improvement beyond this time point according to current PROMs. The KOOS may be a more responsive metric to subjective improvements in this patient cohort than other patient-reported outcomes, such as the IKDC and Lysholm.

CLINICAL RELEVANCE

After ACL reconstruction, patients perceive interval subjective improvements until 1 year postoperatively.

Intra-Articular Hyaluronic Acid in the Symptomatic Treatment of Knee Osteoarthritis: A Meta-Analysis of Single-Injection Products

Background

Viscosupplementation of the synovial fluid with intra-articular hyaluronic acid (IA HA) is a well-known symptomatic treatment of knee osteoarthritis. The question arises whether a monoinjection (ie, single injection) could be as efficient as multi-injection (ie, 3-5 injections) regimens.

Methods

A meta-analysis of published studies relating to IA HA monoinjection trials was performed. The efficacy criterion was the Western Ontario and MacMaster Universities pain subscore. Any study design was accepted, from randomized control trials to single-arm observational open-label studies. An extensive search was performed using PubMed, Google, Google Scholar, and references found in recent meta-analyses, for all articles published before end of April 2018. Population profiles were analyzed in terms of age, sex, body mass index (BMI), and Kellgren-Lawrence (KL) radiology grades. Results of intra-articular single injection of placebo were collected to create a database allowing post hoc comparisons. Each IA HA study arm was compared to an IA placebo arm (either pooled or not), to present a similar KL profile controlled with the χ² test. The effect size (ES) (95% CI) and P values were calculated and synthesized for each follow-up visit at 1, 2, 3, and 6 months. In parallel, a global approach was used to represent the variations from baseline for each group or subgroup studied.

Results

From 1547 citations, 28 studies were included in the meta-analysis, representing 4129 patients treated with monoinjection: 3360 received IA HA and 769 patients received IA placebo. The mean (SD) IA HA patient was 61.2 (9.6) years, 63% women, BMI 28.0 (4.1), 47% KL III, and 3% KL IV. A good placebo KL profile matching was obtained for 26 of the 31 IA HA arms. For the whole IA HA population, ES = 0.30 (95% CI, 0.25-0.35) at 3 months and ES = 0.39 (95% CI, 0.33-0.44) at 6 months. In a restricted analysis, after removal of outliers, poorly KL matched and active arms <30 patients, results remained unchanged, ES = 0.29 (95% CI, 0.23-0.34) and ES = 0.40 (95% CI, 0.34-0.45) at 3 and 6 months respectively, whilst heterogeneity was improved.

Conclusions

There are certainly limits to the post hoc placebo comparison method, for individual studies. But for each synthesis per subgroup or group, the results were properly confirmed using multiple statistical approaches and weighing methods. This meta-analysis suggests that monoinjections produce results similar to multi-injections of IA HA in terms of pain relief in the treatment of knee osteoarthritis. (Curr Ther Res Clin Exp. 2019; 80:XXX-XXX).

Systematic Exposition of Mesenchymal Stem Cell for Inflammatory Bowel Disease and Its Associated Colorectal Cancer

Mesenchymal stem cells (MSCs) therapy has been applied to a wide range of diseases with excessive immune response, including inflammatory bowel disease (IBD), owing to its powerful immunosuppression and its ability to repair tissue lesions. Different sources of MSCs show different therapeutic properties. Engineering managements are able to enhance the immunomodulation function and the survival of MSCs involved in IBD. The therapeutic mechanism of MSCs in IBD mainly focuses on cell-to-cell contact and paracrine actions. One of the promising therapeutic options for IBD can focus on exosomes of MSCs. MSCs hold promise for the treatment of IBD-associated colorectal cancer because of their tumor-homing function and chronic inflammation inhibition. Encouraging results have been obtained from clinical trials in IBD and potential challenges caused by MSCs therapy are getting solved. This review can assist investigators better to understand the research progress for enhancing the efficacy of MSCs therapy involved in IBD and CAC.

Silk/Fibroin Microcarriers for Mesenchymal Stem Cell Delivery: Optimization of Cell Seeding by the Design of Experiment

In this methodological paper, lyophilized fibroin-coated alginate microcarriers (LFAMs) proposed as mesenchymal stem cells (MSCs) delivery systems and optimal MSCs seeding conditions for cell adhesion rate and cell arrangement, was defined by a Design of Experiment (DoE) approach. Cells were co-incubated with microcarriers in a bioreactor for different time intervals and conditions: variable stirring speed, dynamic culture intermittent or continuous, and different volumes of cells-LFAMs loaded in the bioreactor. Intermittent dynamic culture resulted as the most determinant parameter; the volume of LFAMs/cells suspension and the speed used for the dynamic culture contributed as well, whereas time was a less influencing parameter. The optimized seeding conditions were: 98 min of incubation time, 12.3 RPM of speed, and 401.5 µL volume of cells-LFAMs suspension cultured with the intermittent dynamic condition. This DoE predicted protocol was then validated on both human Adipose-derived Stem Cells (hASCs) and human Bone Marrow Stem Cells (hBMSCs), revealing a good cell adhesion rate on the surface of the carriers. In conclusion, microcarriers can be used as cell delivery systems at the target site (by injection or arthroscopic technique), to maintain MSCs and their activity at the injured site for regenerative medicine.

Immune regulatory targets of mesenchymal stromal cell exosomes/small extracellular vesicles in tissue regeneration

Mesenchymal stromal cell (MSC) therapies have demonstrated therapeutic efficacy in a wide-ranging array of tissue injury and disease indications. An important aspect of MSC-mediated therapeutic activities is immune modulation. Consistent with the concentration of MSC therapeutic potency in its secretion, a significant proportion of MSC immune potency resides in the small extracellular vesicles (sEVs) secreted by MSCs. These sEVs, which also include exosomes, carry a large cargo enriched in proteins with potent immunomodulatory activities. They have been reported to exert potent effects on humoral and cellular components of the immune system in vitro and in vivo, and may have the potential to support the diametrically opposite pro- and anti-inflammatory functions necessary for tissue repair and regeneration following injury. Following injury, pro-inflammatory activities are necessary to neutralize injury and remove dead or injured tissue, while anti-inflammatory activities to facilitate migration and proliferation of reparative cell types and to increase vascularization and nutrient supply are necessary to repair and regenerate new tissue. Therefore, a critical immunomodulatory requisite of MSC sEVs in tissue regeneration is the capacity to support the appropriate immune activities at the appropriate time. Here, we review how some of the immune regulatory targets of MSC sEVs could support the dynamic immunomodulatory activities during tissue repair and regeneration.

Mesenchymal Stem Cells in Combination with Hyaluronic Acid for Articular Cartilage Defects

Mesenchymal stem cells (MSCs) and hyaluronic acid (HA) have been found in previous studies to have great potential for medical use. This study aimed to investigate the therapeutic effects of bone marrow mesenchymal stem cells (BMSCs) combined with HA on articular cartilage repair in canines. Twenty-four healthy canines (48 knee-joints), male or female with weight ranging from 5 to 6 kg, were operated on to induce cartilage defect model and divided into 3 groups randomly which received different treatments: BMSCs plus HA (BMSCs-HA), HA alone, and saline. Twenty-eight weeks after treatment, all canines were sacrificed and analyzed by gross appearance, magnetic resonance imaging (MRI), hematoxylin-eosin (HE) staining, Masson staining, toluidine blue staining, type II collagen immunohistochemistry, gross grading scale and histological scores. MSCs plus HA regenerated more cartilage-like tissue than did HA alone or saline. According to the macroscopic evaluation and histological assessment score, treatment with MSCs plus HA also lead to significant improvement in cartilage defects compared to those in the other 2 treatment groups (P < 0.05). These findings suggested that allogeneic BMSCs plus HA rather than HA alone was effective in promoting the formation of cartilage-like tissue for repairing cartilage defect in canines.

Allogeneic Umbilical Cord-Derived Mesenchymal Stem Cells as a Potential Source for Cartilage and Bone Regeneration: An In Vitro Study

Umbilical cord (UC) may represent an attractive cell source for allogeneic mesenchymal stem cell (MSC) therapy. The aim of this in vitro study is to investigate the chondrogenic and osteogenic potential of UC-MSCs grown onto tridimensional scaffolds, to identify a possible clinical relevance for an allogeneic use in cartilage and bone reconstructive surgery. Chondrogenic differentiation on scaffolds was confirmed at 4 weeks by the expression of sox-9 and type II collagen; low oxygen tension improved the expression of these chondrogenic markers. A similar trend was observed in pellet culture in terms of matrix (proteoglycan) production. Osteogenic differentiation on bone-graft-substitute was also confirmed after 30 days of culture by the expression of osteocalcin and RunX-2. Cells grown in the hypertrophic medium showed at 5 weeks safranin o-positive stain and an increased CbFa1 expression, confirming the ability of these cells to undergo hypertrophy. These results suggest that the UC-MSCs isolated from minced umbilical cords may represent a valuable allogeneic cell population, which might have a potential for orthopaedic tissue engineering such as the on-demand cell delivery using chondrogenic, osteogenic, and endochondral scaffold. This study may have a clinical relevance as a future hypothetical option for allogeneic single-stage cartilage repair and bone regeneration.