The effect of intra-articular injection of autologous bone marrow stem cells on pain and knee function in patients with osteoarthritis

Mesenchymal stem cells for chronic knee pain secondary to osteoarthritis: A systematic review and meta-analysis of randomized trials

OBJECTIVE

To assess the effectiveness of mesenchymal stem cells (MSCs) for chronic knee pain secondary to osteoarthritis (OA).

METHODS

We searched MEDLINE, EMBASE, CINAHL, and Cochrane Central to September 2023 for trials that (1) enrolled patients with chronic pain associated with knee OA, and (2) randomized them to MSC therapy vs. placebo or usual care. We performed random-effects meta-analysis and used Grading of Recommendations, Assessment, Development, and Evaluation to assess the certainty of evidence.

RESULTS

We included 16 trials (807 participants). At 3-6 months, MSC therapy probably results in little to no difference in pain relief (weighted mean difference [WMD] -0.74 cm on a 10 cm visual analog scale [VAS], 95% confidence interval [95%CI] -1.16 to -0.33; minimally important difference [MID] 1.5 cm) or physical functioning (WMD 2.23 points on 100-point 36-item Short Form Survey (SF-36) physical functioning subscale, 95%CI -0.97 to 5.43; MID 10-points; both moderate certainty). At 12 months, injection of MSCs probably results in little to no difference in pain (WMD -0.73 cm on a 10 cm VAS, 95%CI -1.69 to 0.24; moderate certainty) and may improve physical functioning (WMD 19.36 points on 100-point SF-36 PF subscale, 95%CI -0.19 to 38.9; low certainty). MSC therapy may increase risk of any adverse events (risk ratio [RR] 2.67, 95%CI 1.19 to 5.99; low certainty) and pain and swelling of the knee joint (RR 1.58, 95%CI 1.04 to 2.38; low certainty).

CONCLUSIONS

Intra-articular injection of MSCs for chronic knee pain associated with OA probably provides little to no improvement in pain or physical function.

Classes of Stem Cells: From Biology to Engineering

Purpose

The majority of adult tissues are limited in self-repair and regeneration due to their poor intrinsic regenerative capacity. It is widely recognized that stem cells are present in almost all adult tissues, but the natural regeneration in adult mammals is not sufficient to recover function after injury or disease. Historically, 3 classes of stem cells have been defined: embryonic stem cells (ESCs), adult mesenchymal stem cells (MSCs), and induced pluripotent stem cells (iPSCs). Here, we have defined a fourth fully engineered class: the synthetic artificial stem cell (SASC). This review aims to discuss the applications of these stem cell classes in musculoskeletal regenerative engineering.

Method

We screened articles in PubMed and bibliographic search using a combination of keywords. Relevant and high-cited articles were chosen for inclusion in this narrative review.

Results

In this review, we discuss the different classes of stem cells that are biologically derived (ESCs and MSCs) or semi-engineered/engineered (iPSCs, SASC). We also discuss the applications of these stem cell classes in musculoskeletal regenerative engineering. We further summarize the advantages and disadvantages of using each of the classes and how they impact the clinical translation of these therapies.

Conclusion

Each class of stem cells has advantages and disadvantages in preclinical and clinical settings. We also propose the engineered SASC class as a potentially disease-modifying therapy that harnesses the paracrine action of biologically derived stem cells to mimic regenerative potential.

Lay Summary

The majority of adult tissues are limited in self-repair and regeneration, even though stem cells are present in almost all adult tissues. Historically, 3 classes of stem cells have been defined: embryonic stem cells (ESCs), adult mesenchymal stem cells (MSCs), and induced pluripotent stem cells (iPSCs). Here, we have defined a fourth, fully engineered class: the synthetic artificial stem cell (SASC). In this review, we discuss the applications of each of these stem cell classes in musculoskeletal regenerative engineering. We further summarize the advantages and disadvantages of using each of these classes and how they impact the clinical translation of these therapies.

Radiofrequency ablation versus intra-articular mesenchymal stem cell injection for knee osteoarthritis: a systematic review and network meta-analysis

BACKGROUND

Knee osteoarthritis (OA) is a prevalent degenerative disease and causes disability, pain and imposes a substantial burden on patients. Conventional treatments for knee OA show limited effectiveness. Consequently, innovative treatments, such as radiofrequency ablation (RFA) and intra-articular mesenchymal stem cells (IA MSC), have gained attention for addressing these limitations.

OBJECTIVE

We compared the efficacy of RFA and IA MSC for knee OA through a network meta-analysis (NMA).

EVIDENCE REVIEW

A literature search was conducted using PubMed, MEDLINE, Embase, Cochrane Library, Web of Science and handsearching. Randomized controlled trials (RCTs) comparing RFA or IA MSC to conventional treatments for knee OA were included. The primary outcomes comprised the pain score and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The clinical outcomes were compared using a frequentist approach, and the treatments were ranked using the surface under the cumulative ranking curve (SUCRA) values.

FINDINGS

We included 34 RCTs (n=2371). Our NMA revealed that RFA and IA MSC were significantly more effective than conventional treatments in managing pain at both 3 and 6 months with moderate certainty. Specifically, RFA demonstrated the highest SUCRA values, indicating its superior efficacy. For WOMAC scores, both RFA and MSC showed significant improvements at 3 months, with RFA maintaining its lead at 6 months, although MSC did not display significant superiority at this stage.

CONCLUSIONS

This analysis suggests that RFA and MSC are resilient treatment options in knee OA. Despite some study heterogeneity, these treatments consistently outperformed conventional treatments, particularly in the short to mid-term, although with varying levels of certainty in their efficacy.

PROSPERO REGISTRATION NUMBER

CRD42023492299.

Comparative Analysis of Short-Term and Long-Term Clinical Efficacy of Mesenchymal Stem Cells from Different Sources in Knee Osteoarthritis: A Network Meta-Analysis

Background

Joint articular injection of mesenchymal stem cells (MSCs) has emerged as a novel treatment approach for osteoarthritis (OA). However, the effectiveness of MSCs derived from different sources in treating OA patients remains unclear. Therefore, this study aimed to explore the differences between the effectiveness and safety of different sources of MSCs.

Materials and Methods

For inclusion consideration, we searched trial registries and published databases, including PubMed, Cochrane Library, Embase, and Web of Science databases. Revman (V5.3), STATA (V16.0), and R (V4.0) were utilized for conducting data analysis, while the Cochrane Risk of Bias Tool was employed for assessing the quality of the studies. We derived outcome measures at 6 and 12 months based on the duration of study follow-up, including visual analog scale (VAS) score, WOMAC score, WOMAC pain, WOMAC Functional Limitation, and WOMAC stiffness. The evaluation time for short-term effectiveness is set at 6 months, while 12 months is utilized as the longest follow-up time for most studies to assess long-term effectiveness.

Results

The evaluation of literature quality showed that the included studies had excellent methodological quality. A meta-analysis revealed that different sources of MSCs improved knee function and pain more effectively among patients suffering from knee OA (KOA) than controls. The results of the network meta-analysis showed the following: short-term functional improvement (the indexes were evaluated after 6 months of follow-up) (WOMAC total score: bone marrow-derived MSC (BMMSC) vs. adipose-derived MSC (ADMSC) (mean difference (MD) = -20.12, 95% confidence interval (CI) -125.24 to 42.88), umbilical cord-derived MSC (UCMSC) (MD = -7.81, 95% CI -158.13 to 74.99); WOMAC stiffness: BMMSC vs. ADMSC (MD = -0.51, 95% CI -7.27 to 4.29), UCMSC (MD = -0.75, 95% CI -9.74 to 6.63); WOMAC functional limitation: BMMSC vs. ADMSC (MD = -12.22, 95% CI -35.05 to 18.86), UCMSC (MD = -9.31, 95% CI -44.26 to 35.27)). Long-term functional improvement (the indexes were evaluated after 12 months of follow-up) (WOMAC total: BMMSC vs. ADMSC (MD = -176.77, 95% CI -757.1 to 378.25), UCMSC (MD = -181.55, 95% CI -937.83 to 541.13); WOMAC stiffness: BMMSC vs. ADMSC (MD = -0.5, 95% CI -26.05 to 18.61), UCMSC (MD = -1.03, 95% CI -30.44 to 21.69); WOMAC functional limitation: BMMSC vs. ADMSC (MD = -5.18, 95% CI -316.72 to 177.1), UCMSC (MD = -8.33, 95% CI -358.78 to 218.76)). Short-term pain relief (the indexes were evaluated after 6 months of follow-up) (VAS score: UCMSC vs. BMMSC (MD = -10.92, 95% CI -31.79 to 12.03), ADMSC (MD = -14.02, 95% CI -36.01 to 9.81), PLMSC (MD = -17.09, 95% CI -46.31 to 13.17); WOMAC pain relief: BMMSC vs. ADMSC (MD = -11.42, 95% CI -39.52 to 11.77), UCMSC (MD = -6.73, 95% CI -47.36 to 29.15)). Long-term pain relief (the indexes were evaluated after 12 months of follow-up) (VAS score: BMMSC vs. UCMSC (MD = -4.33, 95% CI -36.81 to 27.08), ADMSC (MD = -11.43, 95% CI -37.5 to 13.42); WOMAC pain relief: UCMSC vs. ADMSC (MD = 0.23, 95% CI -37.87 to 38.11), BMMSC (MD = 5.89, 95% CI -25.39 to 51.41)). According to the GRADE scoring system, WOMAC, VAS, and AE scores were of low quality.

Conclusion

Meta-analysis suggests MSCs can effectively treat KOA by improving pain and knee function compared to control groups. In terms of functional improvement in KOA patients, both short-term (6-month follow-up) and long-term (12-month follow-up) results indicated that while the differences between most treatments were not statistically significant, bone marrow-derived MSCs may have some advantages over other sources of MSCs. Additionally, BM-MSCs and UC-MSCs may offer certain benefits over ADMSCs in terms of pain relief for KOA patients, although the variances between most studies were not statistically significant. Therefore, this study suggests that BM-MSCs may present clinical advantages over other sources of MSCs.

Stem cells for the treatment of early to moderate osteoarthritis of the knee: a systematic review

PURPOSE

Mesenchymal stem cells (MSCs) present a valuable treatment option for knee osteoarthritis with promising results. The purpose of the present study was to systematically review the clinical and functional outcomes following mesenchymal stem cell application focusing on early to moderate knee osteoarthritis.

METHODS

A systematic search was done using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in Pubmed, Scopus, Web of Science, and Cochrane Library databases. All Studies published between 2017 and March 2023 on patients treated with single mesenchymal stem cell injection for Kellgren-Lawrence grade I-III knee osteoarthritis reported on clinical and functional outcomes were included.

RESULTS

Twelve articles comprising 539 patients and 576 knees treated with a single intraarticular injection of MSCs for knee osteoarthritis were included in the current systematic review. In eligible studies, the reported outcomes were improved concerning patient-reported outcomes measures, knee function, pain relief, and quality of patient's life.

CONCLUSION

Based on high-level evidence studies, single intraarticular injection of MSCs is a safe, reliable, and effective treatment option for Kellgren-Lawrence grade I-III knee osteoarthritis. However, the lack of homogeneity in the included studies and the variance in MSCs sources and preparations should be noted.

LEVEL OF EVIDENCE

III.

Efficacy and Safety of Stempeucel in Osteoarthritis of the Knee: A Phase 3 Randomized, Double-Blind, Multicenter, Placebo-Controlled Study

BACKGROUND

Osteoarthritis is a chronic, progressive, and degenerative condition with limited therapy options. Recently, biologic therapies have been an evolving option for the management of osteoarthritis.

PURPOSE

To assess whether allogenic mesenchymal stromal cells (MSCs) have the potential to improve functional parameters and induce cartilage regeneration in patients with osteoarthritis.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 146 patients with grade 2 and 3 osteoarthritis were randomized to either an MSC group or placebo group with a ratio of 1:1. There were 73 patients per group who received either a single intra-articular injection of bone marrow-derived MSCs (BMMSCs; 25 million cells) or placebo, followed by 20 mg per 2 mL of hyaluronic acid under ultrasound guidance. The primary endpoint was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score. The secondary endpoints were WOMAC subscores for pain, stiffness, and physical function; the visual analog scale score for pain; and magnetic resonance imaging findings using T2 mapping and cartilage volume.

RESULTS

Overall, 65 patients from the BMMSC group and 68 patients from the placebo group completed 12-month follow-up. The BMMSC group showed significant improvements in the WOMAC total score compared with the placebo group at 6 and 12 months (percentage change: -23.64% [95% CI, -32.88 to -14.40] at 6 months and -45.60% [95% CI, -55.97 to -35.23] at 12 months P < .001; percentage change, -44.3%). BMMSCs significantly improved WOMAC pain, stiffness, and physical function subscores as well as visual analog scale scores at 6 and 12 months (P < .001). T2 mapping showed that there was no worsening of deep cartilage in the medial femorotibial compartment of the knee in the BMMSC group at 12-month follow-up, whereas in the placebo group, there was significant and gradual worsening of cartilage (P < .001). Cartilage volume did not change significantly in the BMMSC group. There were 5 adverse events that were possibly/probably related to the study drug and consisted of injection-site swelling and pain, which improved within a few days.

CONCLUSION

In this small randomized trial, BMMSCs proved to be safe and effective for the treatment of grade 2 and 3 osteoarthritis. The intervention was simple and easy to administer, provided sustained relief of pain and stiffness, improved physical function, and prevented worsening of cartilage quality for ≥12 months.

REGISTRATION

CTRI/2018/09/015785 (National Institutes of Health and Clinical Trials Registry-India).

Clinical Trials with Mesenchymal Stem Cell Therapies for Osteoarthritis: Challenges in the Regeneration of Articular Cartilage

Osteoarthritis (OA) is a whole-joint disease primarily characterized by the deterioration of hyaline cartilage. Current treatments include microfracture and chondrocyte implantation as early surgical strategies that can be combined with scaffolds to repair osteochondral lesions; however, intra-articular (IA) injections or implantations of mesenchymal stem cells (MSCs) are new approaches that have presented encouraging therapeutic results in animal models and humans. We critically reviewed clinical trials with MSC therapies for OA, focusing on their effectiveness, quality, and outcomes in the regeneration of articular cartilage. Several sources of autologous or allogeneic MSCs were used in the clinical trials. Minor adverse events were generally reported, indicating that IA applications of MSCs are potentially safe. The evaluation of articular cartilage regeneration in human clinical trials is challenging, particularly in the inflammatory environment of osteoarthritic joints. Our findings indicate that IA injections of MSCs are efficacious in the treatment of OA and the regeneration of cartilage, but that they may be insufficient for the full repair of articular cartilage defects. The possible interference of clinical and quality variables in the outcomes suggests that robust clinical trials are still necessary for generating reliable evidence with which to support these treatments. We suggest that the administration of just-sufficient doses of viable cells in appropriate regimens is critical to achieve effective and durable effects. In terms of future perspectives, genetic modification, complex products with extracellular vesicles derived from MSCs, cell encapsulation in hydrogels, and 3D bioprinted tissue engineering are promising approaches with which to improve MSC therapies for OA.

Mechanisms of analgesic effect of mesenchymal stem cells in osteoarthritis pain

Osteoarthritis (OA) is the most common musculoskeletal disease, and it is a major cause of pain, disability and health burden. Pain is the most common and bothersome presentation of OA, but its treatment is still suboptimal, due to the short-term action of employed analgesics and their poor adverse effect profile. Due to their regenerative and anti-inflammatory properties, mesenchymal stem cells (MSCs) have been extensively investigated as a potential therapy for OA, and numerous preclinical and clinical studies found a significant improvement in joint pathology and function, pain scores and/or quality of life after administration of MSCs. Only a limited number of studies, however, addressed pain control as the primary end-point or investigated the potential mechanisms of analgesia induced by MSCs. In this paper, we review the evidence reported in literature that support the analgesic action of MSCs in OA, and we summarize the potential mechanisms of these antinociceptive effects.

A systematic review, umbrella review, and quality assessment on clinical translation of stem cell therapy for knee osteoarthritis: Are we there yet?

BACKGROUND

The success of stem cell therapy for knee osteoarthritis (KOA) in preclinical animal models has accelerated the pace of clinical translation. However, it remains uncertain whether the current scientific evidence supports the clinical application of stem cells in treating KOA. A comprehensive evaluation of the safety and efficacy of stem cell therapies and scientific evidence quality is necessary.

METHODS

Using "stem cells" and "knee osteoarthritis" as the search terms, several databases, including PubMed, Web of Science, Cochrane, Embase, and Clinicaltrials.gov, were searched on August 25, 2022, and updated on February 27, 2023. Clinical studies that reported adverse reactions (ARs) of stem cell therapy in KOA patients were included without limiting the type of studies. Quantitative systematic reviews of stem cell therapy for KOA that conducted meta-analysis were included. Two researchers conducted literature screening and data extraction independently, and the evidence quality was evaluated according to the Institute of Health Economics and AMSTAR 2 criteria.

RESULTS

Fifty clinical studies and 13 systematic reviews/meta-analyses (SRs/MAs) were included. Nineteen ARs were reported in 50 studies, including five knee-related ARs, seven common ARs, and seven other ARs. Some studies reported over 10% prevalence of knee pain (24.5%; 95% CI [14.7%, 35.7%]), knee effusion (12.5%; 95% CI [4.8%, 22.5%]), and knee swelling (11.9%; 95% CI [3.5%, 23.5%]). Additionally, two studies have reported cases of prostate cancer and breast tumors, respectively. However, these two studies suggest that stem cell therapy does not bring significant ARs to patients. SRs/MAs results revealed that stem cell therapy relieved pain in patients over time but did not improve knee function. However, current clinical studies have limited evidence regarding study objectives, test designs, and patient populations. Similarly, SRs/MAs have inadequate evidence regarding study design, risk of bias assessment, outcome description, comprehensive discussion, and potential conflicts of interest.

CONCLUSIONS

The inefficacy of stem cells, the risk of potential complications, and the limited quality of evidence from current studies precluded any recommendation for using stem cell products in patients with KOA. Clinical translation of stem cell therapies remains baseless and should be cautiously approached until more robust evidence is available. PROSPERO registration number: CRD42022355875.

A Review of Recent Innovations in Cartilage Regeneration Strategies for the Treatment of Primary Osteoarthritis of the Knee: Intra-articular Injections

Background

The pathology of primary osteoarthritis (OA) begins with structural cartilage damage, which initiates a self-propagating inflammatory pathway that further exacerbates cartilage deterioration. Current standard of care for knee primary OA involves treating the inflammatory symptoms to manage pain, which includes intra-articular (IA) injections of cortisone, an anti-inflammatory steroid, followed by a series of joint-cushioning hyaluronic acid gel injections. However, these injections do not delay the progression of primary OA. More focus on the underlying cellular pathology of OA has prompted researchers to develop treatments targeting the biochemical mechanisms of cartilage degradation.

Purpose

Researchers have yet to develop a United States Food and Drug Administration (FDA)-approved injection that has been demonstrated to significantly regenerate damaged articular cartilage. This paper reviews the current research on experimental injections aimed at achieving cellular restoration of the hyaline cartilage tissue of the knee joint.

Study Design

Narrative review.

Methods

The authors conducted a narrative literature review examining studies on primary OA pathogenesis and a systematic review of non-FDA-approved IA injections for the treatment of primary OA of the knee, described as "disease-modifying osteoarthritis drugs" in phase 1, 2, and 3 clinical trials.

Conclusion

New treatment approaches for primary OA investigate the potential of genetic therapies to restore native cartilage. It is clear that the most promising IA injections that could improve treatment of primary OA are bioengineered advanced-delivery steroid-hydrogel preparations, ex vivo expanded allogeneic stem cell injections, genetically engineered chondrocyte injections, recombinant fibroblast growth factor therapy, injections of selective proteinase inhibitors, senolytic therapy via injections, injectable antioxidant therapies, injections of Wnt pathway inhibitors, injections of nuclear factor-kappa β inhibitors, injections of modified human angiopoietin-like-3, various potential viral vector-based genetic therapy approaches, and RNA genetic technology administered via injections.

Regulation of Chondrocyte Differentiation by miR-455-3p Secreted by Bone Marrow Stem Cells through Phosphatase and Tensin Homolog Deleted on Chromosome Ten/Phosphoinositide 3-Kinase-Protein Kinase B

The effects of the regulation of phosphatase and tensin homolog deleted on chromosome ten (PTEN) by microribonucleic acid- (miR-) 455-3p on bone marrow stem cells' (BMSCs') chondrogenic development were examined based on the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signal pathway. The alterations in miR-455-3p and PTEN were identified using osteoarthritis (OA) and healthy chondrocytes. Rats raised on the SD diet had their BMSCs isolated for chondrocyte-induced differentiation (blank group), transfected miR-455-3p mimic (mimic group), and inhibitor (inhibitor group). Besides, cell proliferation, alizarin red mineralization staining, and the activity of alkaline phosphatase (ALP) were detected. Real-time fluorescent quantitation polymerase chain reaction (PCR) and Western blot were utilized to detect Runx2, OPN, OSX, COL2A1 mRNA, and the difference between PI3K and AKT. Dual-luciferase reporter (DLR) genes were selected to analyze the target relationship of miR-455-3p to PTEN. It was demonstrated that miR-455-3p in OA was downregulated, while PTEN was upregulated (P < 0.05) in comparison to healthy chondrocytes (P < 0.05). Versus those in the blank group, alizarin red mineralization staining and the activity of ALP increased; RUNX, OPN, OSX, COL2A1 mRNA, p-PI3K, and p-AKT were elevated in the mimic group (P < 0.05). Versus those in the blank and mimic groups, alizarin red mineralization staining and the activity of ALP reduced; RUNX, OPN, OSX, COL2A1 mRNA, p-PI3K, and p-AKT were downregulated in the inhibitor group (P < 0.05). miR-455-3p could target PTEN to inhibit its expression, thus activating the PI3K/AKT signal pathway and promoting BMSCs chondrocyte-induced differentiation. The research results provided reference for the occurrence of OA and the study on therapeutic target.

Comparative effectiveness of adipose-derived mesenchymal stromal cells in the management of knee osteoarthritis: A meta-analysis

BACKGROUND

Osteoarthritis (OA) is the most common joint disorder, is associated with an increasing socioeconomic impact owing to the ageing population.

AIM

To analyze and compare the efficacy and safety of bone-marrow-derived mesenchymal stromal cells (BM-MSCs) and adipose tissue-derived MSCs (AD-MSCs) in knee OA management from published randomized controlled trials (RCTs).

METHODS

Independent and duplicate electronic database searches were performed, including PubMed, EMBASE, Web of Science, and Cochrane Library, until August 2021 for RCTs that analyzed the efficacy and safety of AD-MSCs and BM-MSCs in the management of knee OA. The visual analog scale (VAS) score for pain, Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), Lysholm score, Tegner score, magnetic resonance observation of cartilage repair tissue score, knee osteoarthritis outcome score (KOOS), and adverse events were analyzed. Analysis was performed on the R-platform using OpenMeta (Analyst) software. Twenty-one studies, involving 936 patients, were included. Only one study compared the two MSC sources without patient randomization; hence, the results of all included studies from both sources were pooled, and a comparative critical analysis was performed.

RESULTS

At six months, both AD-MSCs and BM-MSCs showed significant VAS improvement (P = 0.015, P = 0.012); this was inconsistent at 1 year for BM-MSCs (P < 0.001, P = 0.539), and AD-MSCs outperformed BM-MSCs compared to controls in measures such as WOMAC (P < 0.001, P = 0.541), Lysholm scores (P = 0.006; P = 0.933), and KOOS (P = 0.002; P = 0.012). BM-MSC-related procedures caused significant adverse events (P = 0.003) compared to AD-MSCs (P = 0.673).

CONCLUSION

Adipose tissue is superior to bone marrow because of its safety and consistent efficacy in improving pain and functional outcomes. Future trials are urgently warranted to validate our findings and reach a consensus on the ideal source of MSCs for managing knee OA.

PRISMA-Compliant Meta-Analysis of Randomized Controlled Trials on Osteoarthritis of Knee Managed with Allogeneic vs Autologous MSCs: Efficacy and Safety Analysis

Study Design

Meta-analysis.

Objectives

Our objective is to review the randomized controlled trials (RCTs) that have been conducted previously on the topic of osteoarthritis of the knee to assess and compare the efficacy and safety of autologous and allogeneic sources of mesenchymal stromal cells (MSCs) in the treatment of osteoarthritis.

Materials and methods

We searched the electronic databases PubMed, Embase, Web of Science, and the Cochrane Library until August 2021 for randomised controlled trials (RCTs) analysing the efficacy and safety of autologous and allogeneic sources of MSCs in the management of knee osteoarthritis. These searches were conducted independently and in duplicate. The outcomes that were taken into consideration for analysis were the visual analogue score (VAS) for pain, the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), the Lysholm score, and adverse events. The OpenMeta [Analyst] software was utilised to carry out the analysis in the R platform.

Results

In total, 21 studies with a total of 936 patients were considered for this analysis. Because none of the studies made a direct comparison of the autologous and allogeneic sources of MSCs, we pooled the results of all of the included studies of both sources and made a comparative analysis of how the two types of MSCs fared in their respective applications. Although both allogeneic and autologous sources of MSCs demonstrated significantly better VAS improvement after 6 months (p = 0.006, p = 0.001), this trend was not maintained after 1 year for the allogeneic source (p = 0.171, p = 0.027). When compared to their respective controls based on WOMAC scores after 1 year, autologous sources (p = 0.016) of MSCs performed better than allogeneic sources (p = 0.186).A similar response was noted between the sources at 2 years in their Lysholm scores (p = 0.682, p = 0.017), respectively. Moreover, allogeneic sources (p = 0.039) of MSCs produced significant adverse events than autologous sources (p = 0.556) compared to their controls.

Conclusion

Our analysis of literature showed that autologous sources of MSCs stand superior to allogeneic sources of MSC with regard to their consistent efficacy for pain, functional outcomes, and safety. However, we strongly recommend that further studies be conducted that are of a high enough quality to validate our findings and reach a consensus on the best source of MSCs for use in cellular therapy treatments for knee osteoarthritis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-022-00751-z.

Intra-articular injection choice for osteoarthritis: making sense of cell source-an updated systematic review and dual network meta-analysis

BACKGROUND

Intra-articular injection is indicated for mild or moderate osteoarthritis (OA). However, the superiority of cell-based injection and the role of diverse cell sources are still unclear. This study aimed to compare the therapeutic effect of intra-articular injection with mesenchymal stem cells (MSCs) and cell-free methods for OA treatment.

METHODS

A literature search of published scientific data was carried out from PubMed, MEDLINE, Embase, Cochrane Library, Web of Science, and China National Knowledge Internet (CNKI). Randomized controlled trials (RCTs) compared the efficacy and safety of MSC and cell-free intra-articular injection treatments for OA with at least 6-month follow-up.

RESULTS

Dual network meta-analysis validated the therapeutic advantages of MSC treatments (VAS, Bayesian: 90% versus 10% and SUCRA: 94.9% versus 5.1%; WOMAC total, Bayesian: 83% versus 17% and SUCRA: 90.1% versus 9.9%) but also suggested a potential negative safety induced by cell injection (adverse events, Bayesian: 100% versus 0% and SUCRA: 98.2% versus 1.8%). For the MSC source aspect, adipose mesenchymal stem cells (ADMSCs) and umbilical cord mesenchymal stem cells (UBMSCs) showed a better curative effect on pain relief and function improvement compared with bone marrow mesenchymal stem cells (BMMSCs).

CONCLUSION

Intra-articular injection of MSCs is associated with more effective pain alleviation and function improvement than cell-free OA treatment. However, the potential complications induced by MSCs should be emphasized. A comparative analysis of the MSC sources showed that ADMSCs and UBMSCs exerted a better anti-arthritic efficacy than BMMSCs. Schematic illustration of MSC-based intra-articular injection for treating OA. Three major MSCs (UBMSCs, ADMSCs, and BMMSCs) are extracted and expanded in vitro. Subsequently, the amplified MSCs are concentrated and injected into the knee joint to treat OA.

One of the Primary Functions of Tissue-Resident Pluripotent Pericytes Cells May Be to Regulate Normal Organ Growth and Maturation: Implications for Attempts to Repair Tissues Later in Life

Adult mesenchymal stem cells were reported more than 30 years ago. Since then, their potential to repair and regenerate damaged or diseased tissues has been studied intensively in both preclinical models and human trials. Most of the need for such tissue repair/regeneration is in older populations, so much of the effort has been performed with autologous cells in older patients. However, success has been difficult to achieve. In the literature, it has been noted that such progenitor cells from younger individuals often behave with more vigorous activity and are functionally enhanced compared to those from older individuals or animals. In addition, cells with the characteristics of mesenchymal stem cells or pluripotent mesenchymal regulatory cells exist in nearly all tissues and organs as pericytes since fetal life. Such evidence raises the possibility that one of the primary roles of these organ-specific cells is to regulate organ growth and maturation, and then subsequently play a role in the maintenance of organ integrity. This review will discuss the evidence to support this concept and the implications of such a concept regarding the use of these progenitor cells for the repair and regeneration of tissues damaged by injury or disease later in life. For the latter, it may be necessary to return the organ-specific progenitor cells to the functional state that contributed to their effectiveness during growth and maturation rather than attempting to use them after alterations imposed during the aging process have been established and their function compromised.

Clinical Efficacy of Bone Marrow Aspirate Concentrate Versus Stromal Vascular Fraction Injection in Patients With Knee Osteoarthritis: A Systematic Review and Meta-analysis

BACKGROUND

Knee injection using either bone marrow aspirate concentrate (BMAC) or stromal vascular fraction (SVF) from adipose tissue has been shown to result in symptomatic improvement in patients with knee osteoarthritis (OA). It is still unclear whether one of these therapies is superior over the other.

PURPOSE

To systematically report the clinical studies evaluating BMAC and SVF in the treatment of knee OA and to compare the clinical efficacy of these 2 injection therapies.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

This meta-analysis was performed per the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. Studies were included if they reported the clinical outcomes after a single BMAC or SVF injection in the knee joint of patients with OA. Studies evaluating preparations of culture-expanded stem cells were excluded. A random effects model was used; the clinical efficacy of BMAC or SVF injection was assessed using the standardized mean difference (SMD) and compared. Visual analog scale (VAS) scores for pain and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) knee index were the primary outcomes. The level of statistical significance was set at P < .05.

RESULTS

Ten studies and 472 patients with knee OA who received either BMAC (233 patients) or SVF (239 patients) were included. Patients who received an injection had improved VAS outcomes (mean ± SD): from 5.8 ± 1.3 to 2.6 ± 17 for BMAC and from 6.4 ± 1.4 to 3.4 ± 0.5 for SVF. They also experienced significantly reduced pain (SMD [VAS], 2.6 for BMAC and 3.4 for SVF) and improved function (SMD [WOMAC], 1.4 for BMAC and 1.2 for SVF). However, the SVF injection had a significantly greater effect on pain reduction than did the BMAC injection (P < .0001). Based on WOMAC, the clinical effect of BMAC versus SVF knee injection in patients with knee OA was equivalent (P = .626). Results were limited by the presence of publication bias as well as variability in the preparation methods utilized in the BMAC and SVF injection protocols. Complications were reported in 50% of the BMAC studies (knee stiffness, persistent knee swelling) and 67% of the SVF studies (knee swelling, knee pain, positive SVF cultures without symptoms of infection, and bleeding at the abdominal harvest site).

CONCLUSION

A single BMAC or SVF injection into the knee joint of patients with OA resulted in symptomatic improvement at short-term follow-up. However, SVF seemed to be more effective than did BMAC in the reduction of knee pain. There was significant variation in the BMAC and SVF injection preparation techniques used across the studies and a lack of stratification of outcomes based on the radiologic classification of OA. Therefore, these results should be taken with caution.

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.

Methodological Flaws in Meta-Analyses of Clinical Studies on the Management of Knee Osteoarthritis with Stem Cells: A Systematic Review

(1) Background: Conclusions of meta-analyses of clinical studies may substantially influence opinions of prospective patients and stakeholders in healthcare. Nineteen meta-analyses of clinical studies on the management of primary knee osteoarthritis (pkOA) with stem cells, published between January 2020 and July 2021, came to inconsistent conclusions regarding the efficacy of this treatment modality. It is possible that a separate meta-analysis based on an independent, systematic assessment of clinical studies on the management of pkOA with stem cells may reach a different conclusion. (2) Methods: PubMed, Web of Science, and the Cochrane Library were systematically searched for clinical studies and meta-analyses of clinical studies on the management of pkOA with stem cells. All clinical studies and meta-analyses identified were evaluated in detail, as were all sub-analyses included in the meta-analyses. (3) Results: The inconsistent conclusions regarding the efficacy of treating pkOA with stem cells in the 19 assessed meta-analyses were most probably based on substantial differences in literature search strategies among different authors, misconceptions about meta-analyses themselves, and misconceptions about the comparability of different types of stem cells with regard to their safety and regenerative potential. An independent, systematic review of the literature yielded a total of 183 studies, of which 33 were randomized clinical trials, including a total of 6860 patients with pkOA. However, it was not possible to perform a scientifically sound meta-analysis. (4) Conclusions: Clinicians should interpret the results of the 19 assessed meta-analyses of clinical studies on the management of pkOA with stem cells with caution and should be cautious of the conclusions drawn therein. Clinicians and researchers should strive to participate in FDA and/or EMA reviewed and approved clinical trials to provide clinically and statistically valid efficacy.

The promising role of autologous and allogeneic mesenchymal stromal cells in managing knee osteoarthritis. What is beyond Mesenchymal stromal cells?

Mesenchymal stromal cells (MSCs) express a wide range of properties anticipated to be beneficial for treating genetic, mechanical, and age-related degeneration in diseases such as osteoarthritis (OA). Although contemporary conservative management of OA is successful in many patients with mild-moderate OA, it often fails to improve symptoms in many patients who are not a candidate for any surgical management. Further, existing conservative treatment strategies do not prevent the progression of the disease and therefore fail to provide a long-term pain-free life. On the other hand, tremendous progress has been taking place in the exciting field of regenerative medicine involving MSCs (autologous and allogeneic), with promising translation taking place from basic science to the bedside. In this review, we comprehensively discuss the potential role of MSCs in treating OA, both autologous and off-the-shelf, allogeneic stem cells. Further, newer therapies are in the offing to treat OA, such as exosomes and growth factors.

What is the clinically significant ideal mesenchymal stromal cell count in the management of osteoarthritis of the knee? - Meta-analysis of randomized controlled trials

STUDY DESIGN

Meta-analysis.

OBJECTIVES

We aim to identify the clinically significant ideal Mesenchymal Stem Cell (MSC) count in the management of osteoarthritis of knee from Randomized Controlled Trials (RCTs) available in the literature.

MATERIALS AND METHODS

We conducted independent and duplicate electronic database searches including PubMed, Embase, Web of Science, and Cochrane Library till August 2021 for RCTs conducted in the management of knee osteoarthritis using MSC therapy specifying the quantity of MSCs delivered. We categorized the studies based on the MSC count utilized in them into four groups namely <1 × 10⁷ MSCs (Group I), 1-5x10⁷ MSCs (Group II), 5-10 × 10⁷ MSCs (Group III), and >10 × 10⁷ MSCs (Group IV). Visual Analog Score (VAS) for Pain, Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), Lysholm score, Knee Osteoarthritis Outcome Score (KOOS), and adverse events were the outcomes analyzed. Analysis was performed in R-platform using OpenMeta [Analyst] software.

RESULTS

14 studies involving 564 patients were included for analysis. We noted incremental decrease in the VAS with increasing dosage of MSCs at 12 months [Group I,WMD = 2.641(p = 0.854); Group II, WMD = -4.853(p = 0.379); Group III, WMD = -12.154 (p = 0.316); Group IV, WMD = -15.935(p = 0.116)], and 24 months [Group I,WMD = -6(p = 0.001); Group II, WMD = -15(p = 0.001); Group IV, WMD = -20(p = 0.001)]. We also noted incremental improvement in the WOMAC, KOOS with increasing dosage of MSCs at 12 months [Group I, WMD = 7(p = 0.001); Group II, WMD = 28(p = 0.001); Group IV, WMD = 30(p = 0.001)] and [Group II, WMD = -2.562(p = 0.676); Group III, WMD = 7.670(p = 0.099); Group IV, WMD = 13.475(p = 0.261)] respectively. However, we noted significant reduction in the Lysholm score in Group IV, compared to the others at 12 months (WMD = -12.5, 95%CI[-25.883,0.883]) and 24 months (WMD = -6.6, 95%CI[-23.596,10.396]). We did not find any significant increase in the adverse events with incremental dosage of MSCs in any of the groups compared.

CONCLUSION

Compared to the four dosage groups of MSCs analyzed, Group III showed consistent significant improvement in pain and functional outcomes analyzed compared to the other groups. Hence, we recommend a cell volume of 5-10 × 10⁷ cells to be delivered to the target site to obtain superior benefits out of the procedure. However, we urge future trials of sufficient quality to validate our findings to arrive at a consensus on the ideal count of MSCs to be delivered in the cellular therapy for knee osteoarthritis.

Does vehicle-based delivery of mesenchymal stromal cells give superior results in knee osteoarthritis? Meta-analysis of randomized controlled trials

STUDY DESIGN

Meta-analysis.

OBJECTIVES

We aim to analyze and compare the efficacy and safety of vehicle-based delivery of Mesenchymal Stromal Cells (MSCs) in the management of osteoarthritis of the knee from Randomized Controlled Trials (RCTs) available in the literature.

MATERIALS AND METHODS

We conducted independent and duplicate electronic database searches including PubMed, Embase, Web of Science, and Cochrane Library till August 2021 for RCTs analyzing the efficacy and safety of vehicle-based delivery of MSCs in the management of knee osteoarthritis. Visual Analog Score (VAS) for Pain, Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score, and adverse events were the outcomes analyzed. Analysis was performed in R-platform using OpenMeta [Analyst] software.

RESULTS

21 studies involving 936 patients were included for analysis. None of the studies made a direct comparison of the direct and vehicle-based delivery of MSCs, hence we pooled the results of all the included studies of both groups and made a comparative analysis of their outcomes. Although at 6 months, both direct and vehicle-based delivery of MSCs showed significantly better VAS improvement (p = 0.002, p = 0.010), it was not consistent at 1 year for the vehicle delivery (p = 0.973). During 6 months and 12 months, direct delivery of MSCs (p < 0.001, p < 0.001) outperformed vehicle delivery (p = 0.969, p = 0.922) compared to their control based on WOMAC scores respectively. Both direct (p = 0.713) and vehicle-based delivery (p = 0.123) of MSCs did not produce significant adverse events compared to their controls.

CONCLUSION

Our analysis of literature showed that current clinically employed methods of vehicle-based delivery of MSCs such as platelet-rich plasma, hyaluronic acid did not demonstrate superior results compared to direct delivery, concerning the efficacy of treatment measured by improvement in pain, functional outcomes, and safety. Hence, we urge future clinical trials to be conducted to validate the effectiveness of advanced delivery vehicles such as composite bioscaffolds to establish their practical utility in cartilage regeneration with respect to its encouraging in-vitro evidence.

Impact of the Process Variables on the Yield of Mesenchymal Stromal Cells from Bone Marrow Aspirate Concentrate

Human bone marrow (BM) has been highlighted as a promising source of mesenchymal stromal cells (MSCs) containing various growth factors and cytokines that can be potentially utilized in regenerative procedures involving cartilage and bone. However, the proportion of MSCs in the nucleated cell population of BM is only around 0.001% to 0.01% thereby making the harvesting and processing technique crucial for obtaining optimal results upon its use in various regenerative processes. Although several studies in the literature have given encouraging results on the utility of BM aspiration concentrate (BMAC) in various regenerative procedures, there is a lack of consensus concerning the harvesting variables such as choice of anesthetic agent to be used, site of harvest, size of the syringe to be used, anticoagulant of choice, and processing variables such as centrifugation time, and speed. In this review article, we aim to discuss the variables in the harvesting and processing technique of BMAC and their impact on the yield of MSCs in the final concentrate obtained from them.

Engineered adipose-derived stem cells with IGF-1-modified mRNA ameliorates osteoarthritis development

BACKGROUND

Osteoarthritis (OA), a prevalent degenerative disease characterized by degradation of extracellular matrix (ECM), still lacks effective disease-modifying therapy. Mesenchymal stem cells (MSCs) transplantation has been regarded as the most promising approach for OA treatment while engrafting cells alone might not be adequate for effective regeneration. Genetic modification has been used to optimize MSC-based therapy; however, there are still significant limitations that prevent the clinical translation of this therapy including low efficacy and safety concerns. Recently, chemically modified mRNA (modRNA) represents a promising alternative for the gene-enhanced MSC therapy. In this regard, we hypothesized that adipose derived stem cells (ADSCs) engineered with modRNA encoding insulin-like growth factor 1 (IGF-1) were superior to native ADSCs on ameliorating OA development.

METHODS

Mouse ADSCs were acquired from adipose tissue and transfected with modRNAs. First, the kinetics and efficacy of modRNA-mediated gene transfer in mouse ADSCs were analyzed in vitro. Next, we applied an indirect co-culture system to analyze the pro-anabolic potential of IGF-1 modRNA engineered ADSCs (named as IGF-1-ADSCs) on chondrocytes. Finally, we evaluated the cell retention and chondroprotective effect of IGF-1-ADSCs in vivo using fluorescent labeling, histology and immunohistochemistry.

RESULTS

modRNA transfected mouse ADSCs with high efficiency (85 ± 5%) and the IGF-1 modRNA-transfected ADSCs facilitated burst-like production of bio-functional IGF-1 protein. In vitro, IGF-1-ADSCs induced increased anabolic markers expression of chondrocytes in inflammation environment compared to untreated ADSCs. In a murine OA model, histological and immunohistochemical analysis of knee joints harvested at 4 weeks and 8 weeks after OA induction suggested IGF-1-ADSCs had superior therapeutic effect over native ADSCs demonstrated by lower histological OARSI score and decreased loss of cartilage ECM.

CONCLUSIONS

These findings collectively supported the therapeutic potential of IGF-1-ADSCs for clinical OA management and cartilage repair.

Expanded Mesenchymal Stromal Cells in knee osteoarthritis: A systematic literature review

OBJECTIVE

To analyse the efficacy and safety of intra-articular injection of expanded Mesenchymal Stromal Cells (MSCs) in knee osteoarthritis.

METHODS

Systematic Literature Review. A pre-defined search strategy was run in Medline, Embase and Cochrane Library until February 2018.

INCLUSION CRITERIA

knee osteoarthritis (grades II-IV Kellgren-Lawrence); intra-articular injection of MSCs (without surgical co-treatments); Randomized Controlled Trials (RCTs) or Quasi-experimental Clinical Trials (QCTs) N ≥ 10 and ≥6 months of follow-up were included. Evidence was assigned according to the Scottish Intercollegiate Guidelines Network (SIGN).

RESULTS

The search identified 252 articles. Nine proof-of-concept trials (3 RCTs, 6 QCTs) were included (N = 169). Evidence showed clinical improvement in 60% of patients. Structural benefit was reported in half of patients. Clinical benefit was observed from the 3^rd month and structural improvement from the 6^th. All studies reported maximum clinical and structural benefit a year following the implant. This benefit was sustained for up to 24 months. Studies with doses ≥40 × 10⁶ showed more consistent clinical and structural benefits than those with lower doses. No systemic adverse reactions were reported. The most common adverse effect was pain and/or inflammation in the puncture area (13-53%). The use of donor cells was as safe as autologous implants.

CONCLUSIONS

Intra-articular implants of MSCs seem to be safe with no serious adverse effects. Low-quality evidence precludes conclusions regarding efficacy in this review. However, the clinical and structural benefits observed provide a rationale for using expanded MSCs implants in osteoarthritis patients. High-quality evidence trials are needed to further determine best protocols to maximize clinical and structural improvement.

Is Culture Expansion Necessary in Autologous Mesenchymal Stromal Cell Therapy to Obtain Superior Results in the Management of Knee Osteoarthritis?-Meta-Analysis of Randomized Controlled Trials

Study Design: Meta-analysis. Objectives: We aimed to analyze the impact of cultured expansion of autologous mesenchymal stromal cells (MSCs) in the management of osteoarthritis of the knee from randomized controlled trials (RCTs) available in the literature. Materials and Methods: We conducted independent and duplicate electronic database searches including PubMed, Embase, Web of Science, and Cochrane Library until August 2021 for RCTs analyzing the efficacy and safety of culture-expanded compared to non-cultured autologous MSCs in the management of knee osteoarthritis. The Visual Analog Score (VAS) for pain, Western Ontario McMaster University's Osteoarthritis Index (WOMAC), Lysholm score, Knee Osteoarthritis Outcome Score (KOOS), and adverse events were the analyzed outcomes. Analysis was performed in R-platform using OpenMeta [Analyst] software. Results: Overall, 17 studies involving 767 patients were included for analysis. None of the studies made a direct comparison of the culture expanded and non-cultured MSCs, hence we pooled the results of all the included studies of non-cultured and cultured types of MSC sources and made a comparative analysis of the outcomes. At six months, culture expanded MSCs showed significantly better improvement (p < 0.001) in VAS outcome. Uncultured MSCs, on the other hand, demonstrated significant VAS improvement in the long term (12 months) in VAS (p < 0.001), WOMAC (p = 0.025), KOOS score (p = 0.016) where cultured-expanded MSCs failed to demonstrate a significant change. Culturing of MSCs did not significantly increase the complications noted (p = 0.485). On sub-group analysis, adipose-derived uncultured MSCs outperformed culture-expanded MSCs at both short term (six months) and long term (12 months) in functional outcome parameters such as WOMAC (p < 0.001, p = 0.025), Lysholm (p < 0.006), and KOOS (p < 0.003) scores, respectively, compared to their controls. Conclusions: We identified a void in literature evaluating the impact of culture expansion of MSCs for use in knee osteoarthritis. Our indirect analysis of literature showed that culture expansion of autologous MSCs is not a necessary factor to obtain superior results in the management of knee osteoarthritis. Moreover, while using uncultured autologous MSCs, we recommend MSCs of adipose origin to obtain superior functional outcomes. However, we urge future trials of sufficient quality to validate our findings to arrive at a consensus on the need for culture expansion of MSCs for use in cellular therapy of knee osteoarthritis.

Does the Source of Mesenchymal Stem Cell Have an Effect in the Management of Osteoarthritis of the Knee? Meta-Analysis of Randomized Controlled Trials

STUDY DESIGN

Meta-analysis.

OBJECTIVES

To compare the efficacy and safety of bone marrow(BM)-derived mesenchymal stem cell(MSCs) and adipose-derived(AD) MSCs in the management of osteoarthritis of knee from randomized controlled trials(RCTs) available in the literature.

MATERIALS AND METHODS

We conducted electronic database searche from PubMed, Embase, and Cochrane Library till May 2020 for RCTs analyzing the efficacy and safety of MSCs in management of osteoarthritis of knee. Visual Analog Score(VAS) for Pain, Western Ontario McMaster Universities Osteoarthritis Index(WOMAC), Lysholm Knee Scale(Lysholm), Whole-Organ Magnetic Resonance Imaging Score(WORMS), Knee Osteoarthritis Outcome Score(KOOS), and adverse events were the outcomes analyzed. Analysis was performed in R platform using OpenMeta[Analyst] software.

RESULTS

Nineteen studies involving 811 patients were included for analysis. None of the studies compared the source of MSCs for osteoarthritis of knee and results were obtained by pooled data analysis of both sources. At 6 months, AD-MSCs showed significantly better VAS(P<0.001,P=0.069) and WOMAC(P=0.134,P=0.441) improvement than BM-MSCs, respectively, compared to controls. At 1 year, AD-MSCs outperformed BM-MSCs compared to their control in measures like WOMAC(P=0.007,P=0.150), KOOS(P<0.001;P=0.658), and WORMS(P<0.001,P=0.041), respectively. Similarly at 24 months, AD-MSCs showed significantly better Lysholm score(P=0.037) than BM-MSCs(P=0.807) although VAS improvement was better with BM-MSCs at 24 months(P<0.001). There were no significant adverse events with either of the MSCs compared to their controls.

CONCLUSION

Our analysis establishes the efficacy, safety, and superiority of AD-MSC transplantation, compared to BM-MSC, in the management of osteoarthritis of knee from available literature. Further RCTs are needed to evaluate them together with standardized doses.

Platelet-Rich Plasma and Stem Cell Injections in the Treatment of Arthritis of the Knee

Platelet-rich plasma (PRP) and stem cell (SC) injections have become increasingly common in the treatment of knee arthritis. This systematic review was performed to answer the following questions: (1) What effects does intraarticular PRP injection have in the setting of knee arthritis? (2) What effects does intra-articular SC injection have in the setting of knee arthritis? (3) What adverse events have been reported in the literature from PRP injections for knee arthritis? (4) What adverse events have been reported in the literature from SC injections for knee arthritis? [Orthopedics. 2021;44(6):376-383.].

Intra-articular Injections of Mesenchymal Stem Cells Without Adjuvant Therapies for Knee Osteoarthritis: A Systematic Review and Meta-analysis

BACKGROUND

While many reviews have been performed to attempt to provide conclusive evidence regarding the outcomes of mesenchymal stem cells (MSCs) in osteoarthritis treatment, the evidence for MSC treatment in osteoarthritis remains contentious, as these reviews have been limited by the heterogeneous evidence available.

PURPOSE

To pool the results of treatment using intra-articular injections of MSCs without any adjuvant therapies for osteoarthritis.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

The review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. All clinical trials of level 1 or 2 evidence that reported clinical outcomes of patients with osteoarthritis of the knees treated using intra-articular injections of MSCs without any adjuvant therapies were included.

RESULTS

A total of 19 studies with 440 knees were included. All studies reported an improvement in the outcomes after intervention. The standardized mean differences (SMDs) for the visual analog scale (VAS) for pain at rest and upon exertion were -1.48 (95% CI, -1.85 to -1.11) and -2.25 (95% CI, -2.64 to -1.85), respectively. The SMDs for the total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and total Knee injury and Osteoarthritis Outcome Score were -1.19 (95% CI, -1.53 to -0.84) and 0.88 (95% CI, 0.66-1.10), respectively. Only the source of MSCs and whether the MSCs were cultured or uncultured were clinically important and statistically significant moderators of the treatment outcome. The use of bone marrow MSCs reduced the VAS for pain by 1.50 (95% CI, 0.04-2.96; P = .04) and reduced the total WOMAC by 23.2 (95% CI, 10.0-36.4; P < .01) as compared with adipose MSCs. The use of cultured MSCs reduced the VAS for pain by 2.19 (95% CI, 0.57-3.81; P < .01) and reduced the total WOMAC by 14.4 (95% CI, 1.21-27.5; P = .03) as compared with uncultured MSCs.

CONCLUSION

Intra-articular injections of MSCs without any adjuvant therapies improves pain and function for osteoarthritis. Significantly better outcomes were obtained with the use of bone marrow MSCs as compared with adipose MSCs and with the use of cultured MSCs as opposed to uncultured MSCs.

Advantages and challenges of stem cell therapy for osteoarthritis (Review)

Osteoarthritis (OA) is a degenerative disorder of the cartilage and is one of the leading causes of disability, particularly amongst the elderly, wherein patients with advanced-stage OA experience chronic pain and functional impairment of the limbs, thus resulting in a significantly reduced quality of life. The currently available treatments primarily revolve around symptom management, and is thus palliative rather than curative. The aim of the present review is to briefly discuss the limitations of some of the currently available treatments for patients with OA, and highlight the value of the potential use of stem cells in cellular therapy, which is widely regarded as the breakthrough that can address the present unmet medical needs for treatment of degenerative diseases, such as OA. The advantages of stem cell therapy, particularly mesenchymal stem cells, and the challenges involved are also discussed in this review.

Mesenchymal stem cells and extracellular vesicles for the treatment of pain: Current status and perspectives

Mesenchymal stem/stromal cells (MSCs) are multipotent progenitor cells of mesodermal origin. Due to their capacity for self-renewal and differentiation into several cell types, MSCs have been extensively studied in experimental biology and regenerative medicine in recent years. Moreover, MSCs release extracellular vesicles (EVs), which might be partly responsible for their regenerative properties. MSCs regulate several processes in target cells via paracrine signalling, such as immunomodulation, anti-apoptotic signalling, tissue remodelling, angiogenesis and anti-fibrotic signalling. The aim of this review is to provide a detailed description of the functional properties of MSCs and EVs and their potential clinical applications, with a special focus on pain treatment. The analgesic, anti-inflammatory and regenerative properties of MSCs and EVs will be discussed for several diseases, such as neuropathic pain, osteoarthritis and spinal cord injury.

Extracellular Vesicles from Mesenchymal Stem Cells as Potential Treatments for Osteoarthritis

Osteoarthritis (OA) is a chronic degenerative disorder of the joint and its prevalence and severity is increasing owing to ageing of the population. Osteoarthritis is characterized by the degradation of articular cartilage and remodeling of the underlying bone. There is little understanding of the cellular and molecular processes involved in pathophysiology of OA. Currently the treatment for OA is limited to painkillers and anti-inflammatory drugs, which only treat the symptoms. Some patients may also undergo surgical procedures to replace the damaged joints. Extracellular vesicles (EV) play an important role in intercellular communications and their concentration is elevated in the joints of OA patients, although their mechanism is unclear. Extracellular vesicles are naturally released by cells and they carry their origin cell information to be delivered to target cells. On the other hand, mesenchymal stem cells (MSCs) are highly proliferative and have a great potential in cartilage regeneration. In this review, we provide an overview of the current OA treatments and their limitations. We also discuss the role of EV in OA pathophysiology. Finally, we highlight the therapeutic potential of MSC-derived EV in OA and their challenges.

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.

Stem cell transplantation for the treatment of osteochondral defects of the knee: Operative technique for a single-stage transplantation procedure using bone marrow-derived mesenchymal stem cells

BACKGROUND

Autologous chondrocyte implantation (ACI) is a NICE-approved technique to regenerate hyaline cartilage in chondral and osteochondral defects (OCDs). The drawbacks of ACI include that it requires a two-stage approach, involves a lengthy rehabilitation process and is expensive. Bone marrow harvest with mesenchymal stem cell transplantation using a single-stage procedure and an accelerated rehabilitation programme has been developed to overcome this. The aim of this paper is to describe the surgical technique for stem cell transplantation of the knee for OCDs with reference to case examples.

METHODS

The surgical technique for stem cell transplantation of the knee for OCDs is described, with reference to three cases. Magnetic resonance imaging was performed at six months postoperatively.

RESULTS

The surgical technique is described in this paper. The three patient cases described all improved clinically with reduced pain and improved function at a minimum of six months follow-up.

CONCLUSIONS

Stem cell transplantation has the potential to produce favourable outcomes for patients with osteochondral defects of the knee. This single-stage approach and accelerated rehabilitation is associated with reduced financial costs. A long-term prospective study of this technique is currently underway at our institution and randomised controlled trials are planned to demonstrate the effectiveness over other techniques.

Expanded Mesenchymal Stromal Cells in Knee Osteoarthritis: A Systematic Literature Review

OBJECTIVE

To analyse the efficacy and safety of intra-articular injection of expanded Mesenchymal Stromal Cells (MSCs) in knee osteoarthritis.

METHODS

Systematic Literature Review. A pre-defined search strategy was run in Medline, Embase and Cochrane Library until February 2018.

INCLUSION CRITERIA

knee osteoarthritis (grades II-IV Kellgren-Lawrence); intra-articular injection of MSCs (without surgical co-treatments); Randomized Controlled Trials (RCTs) or Quasi-experimental Clinical Trials (QCTs) N≥10 and ≥6 months of follow-up were included. Evidence was assigned according to the Scottish Intercollegiate Guidelines Network (SIGN).

RESULTS

The search identified 252 articles. Nine proof-of-concept trials (3 RCTs, 6 QCTs) were included (N=169). Evidence showed clinical improvement in 60% of patients. Structural benefit was reported in half of patients. Clinical benefit was observed from the 3rd month and structural improvement from the 6th. All studies reported maximum clinical and structural benefit a year following the implant. This benefit was sustained for up to 24 months. Studies with doses ≥40×106 showed more consistent clinical and structural benefits than those with lower doses. No systemic adverse reactions were reported. The most common adverse effect was pain and/or inflammation in the puncture area (13-53%). The use of donor cells was as safe as autologous implants.

CONCLUSIONS

Intra-articular implants of MSCs seem to be safe with no serious adverse effects. Low-quality evidence precludes conclusions regarding efficacy in this review. However, the clinical and structural benefits observed provide a rationale for using expanded MSCs implants in osteoarthritis patients. High-quality evidence trials are needed to further determine best protocols to maximize clinical and structural improvement.

Intra-articular Injection of Culture-Expanded Mesenchymal Stem Cells Without Adjuvant Surgery in Knee Osteoarthritis: A Systematic Review and Meta-analysis

BACKGROUND

Although many clinical studies have assessed the efficacy of mesenchymal stem cells (MSCs) in knee osteoarthritis, evidence on their efficacy remains unclear owing to heterogeneity of cell entity and concomitant procedures.

PURPOSE

To determine the efficacy of culture-expanded MSCs in knee osteoarthritis in terms of clinical outcome and cartilage repair via meta-analysis of randomized controlled trials (RCTs) without adjuvant surgery.

STUDY DESIGN

Meta-analysis.

METHODS

PubMed, Embase, the Cochrane Library, CINAHL, and Scopus were searched from inception to December 31, 2018. RCTs with culture-expanded MSCs for treating knee osteoarthritis were included. Studies with adjuvant surgery or cell concentrate were excluded. Quality was assessed by the Cochrane Collaboration risk-of-bias tool. For meta-analysis, data on clinical outcomes were measured using a visual analog scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and data on cartilage repair were measured using the Whole-Organ Magnetic Resonance Imaging Score (WORMS); categorization related to improvement was extracted.

RESULTS

Six RCTs (203 patients) were included. Two studies were deemed to have a low risk of bias. In pooled analysis, the only significant difference was in the VAS score (mean difference, -13.55; 95% CI, -22.19 to -4.9). In cumulative pain analysis with VAS and WOMAC pain scores, there was significant improvement after treatment (standardized mean difference, -0.54; 95% CI, -0.85 to -0.23). There was no significant difference in cartilage repair assessed by magnetic resonance imaging (standardized mean difference, 0.11; 95% CI, -0.51 to 0.73), WORMS (standardized mean difference, 1.68; 95% CI -14.84 to 18.21), or categorical results (odds ratio, 1.56; 95% CI, 0.32-7.59).

CONCLUSION

Intra-articular injection of culture-expanded MSCs without adjuvant surgery can improve pain for patients experiencing knee osteoarthritis at short-term follow-up (6-12 months). However, evidence regarding function and cartilage repair remains limited.

Lack of standardization among clinical trials of injection therapies for knee osteoarthritis: a systematic review

Purpose: Osteoarthritis (OA) of the knee is a debilitating, expensive, and prevalent disease, and interest in the non-surgical management of knee OA has grown recently. Our objective was to systematically assess the level of heterogeneity among all clinical trials and published studies regarding injections for knee osteoarthritis, in terms of treatment of interest, outcomes evaluated, and time points of outcome assessment. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were utilized to review all published studies and publically available clinical trials from 1 January 2013 to 3 May 2019evaluating intra-articular injections to treat knee OA. Their treatment group and specifics of methodology were scrutinized and compared. Results: 84 published studies and 114 clinical trials were included. Within the 84 published studies, the most common injection treatment studied was hyaluronic acid [N = 22; 26.2%]. In total, 29 different injection treatment groups were utilized. The most common time point for patient evaluation post-injection was 6 months (N = 33 studies; 50.0%), and ranged from 1 week (N = 9 studies; 13.6%) to 7 years (N = 1 study; 1.5%). The most common patient-reported outcome (PRO) measure assessed in the included studies was Western Ontario and McMaster's University Osteoarthritis Index (WOMAC) [N = 44 studies; 66.7%]. For the 114 clinical trials identified, the most common injection treatment studied is platelet-rich plasma in isolation (N = 19; 16.7%). Forty-two different injection treatment types/groups are utilized. The most common PRO measure assessed was WOMAC (N = 77 trials; 67.5%). Overall there were 34 different patient-reported outcome measures used. Conclusions: Research efforts to find the most effective injection therapy for knee OA continue with a tremendous number of injection therapies still being evaluated. Substantial heterogeneity exists in these completed and ongoing trials in terms of patient demographics, OA grades, outcome scores and relatively short-term timing of assessments, with no clear standardization of testing protocol despite proposing to answer the same clinical question. We recommend that studies of this genre going forward be standardized in terms of outcome measures and longer-term follow-up time points, and should incorporate functional assessment evaluations and imaging studies.

Autologous Mesenchymal Stem Cell Treatment is Consistently Effective for the Treatment of Knee Osteoarthritis: The Results of a Systematic Review of Treatment and Comparison to a Placebo Group

Background: Numerous studies have used autologous mesenchymal stem cell injections (AMSCI) to treat osteoarthritis. We hypothesized that AMSCI is an effective osteoarthritis treatment with increasing efficacy at higher doses. Methods: We conducted a PubMed search for human clinical studies using AMSCI for the treatment of osteoarthritis (OA) and a second search for placebo arms of injectate OA treatment. Inclusion criteria included treatment outcomes ratings both pre-treatment and at least 6 months post-treatment. Results: 45 AMSCI cohorts from 34 studies met criteria. All AMSCI cohorts showed improvement at mean 15.3 months post-treatment. Mean WOMAC and VAS scores improved at 6-months and at final follow-up (p < 0.0001 for all). Scores > 2 years were also significant (WOMAC p = 0.001/VAS p = 0.004). Results greatly exceeded the minimal clinically important difference (MCID) at each time point. AMSCI improvement also substantially exceeded previously published 6-month placebo-treatment improvement. No dose-response relationship was seen. AMSCI cohorts showed continuing improvement ≥ 6 months, and continued upward at one year. Placebo scores were already trending downward by 6 months. Conclusions: AMSCI is a consistently significantly effective treatment for osteoarthritis. It should no longer be stated that data is insufficient to establish AMSCI efficacy for OA. Given its excellent safety profile, AMSCI should be widely used for the treatment of osteoarthritis.

Improved outcomes after mesenchymal stem cells injections for knee osteoarthritis: results at 12-months follow-up: a systematic review of the literature

PURPOSE

According to the World Health organization (WHO), more than 10% in people older than 60 years suffer from osteoarthritis (OA). Over the last years, there has been an increased interest around regenerative medicine, especially regarding stem cell treatments and related applications. We hypothesize that stem cell therapies can represent a feasible option for idiopathic knee OA, delaying or even avoiding the joint replacement. To emphasize the potential of percutaneous injections of mesenchymal stem cells for knee OA, a comprehensive systematic review of the literature was conducted.

MATERIAL AND METHODS

Two independent authors (FM, GC) performed the literature search. This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA). The main databases were accessed: Pubmed, Embase, Google Scholar, Cochrane Systematic Reviews, Scopus, AMED. For this systematic review, all articles treating percutaneous injections of mesenchymal stem cells for knee OA were considered. Because of the rapid advancements promoted by the scientific progress on stem cell expansion and processing, only articles published within the last five years were included. Solely articles reporting the outcomes of interest across 6- and 12-month follow-up were recruited for eligibility. We included only studies reporting quantitative data under the outcomes of interest. We referred for the quality assessment to the Coleman Methodology Score (CMS). The statistical analysis was performed with Review Manager Software 5.3 (The Nordic Cochrane Centre, Copenhagen).

RESULTS

A total of 18 studies were enrolled in the present study, comprising 1069 treated knees. The mean age of the samples was 57.39 ± 7.37 years. 72% of the included studies harvested the stem cells from the iliac crest (bone marrow-derived MSCs), the remaining 28% from the adipose tissue (adipose-derived MSCs). The mean visual analogic scale improved from 18.37 to 30.98 and 36.91 at 6- and 12-month follow-up, respectively. The mean WOMAC score improved from 25.66 to 25.23 and 15.60 at 6- and 12-month follow-up, respectively. The mean walking distance improved from 71.90 to 152.22 and 316.72 at 6- and 12-month follow-up, respectively. The mean Lequesne scale improved from 33.76 to 12.90 at 12-month follow-up. The KOOS score improved from 41.07 to 8.47% and 18.94 at 6- and 12-month follow-up. All the KOOS subscales improved significantly from the baseline. A total of 136 (12.7%) local complications were detected.

CONCLUSION

According to the current evidences and the main findings of this systematic review, we reported that MSC infiltrations for knee OA can represent a feasible option, leading to an overall remarkable improvement of all clinical and functional considered outcomes, regardless of the cell source. Patients treated at earlier-degeneration stages reported statistically significant greater outcomes. The pain and function scores were improved considerably, thus, leading to a significant improvement of patient participation in recreational activities and quality of life.

Autologous Biologic Treatment with Fat, Bone Marrow Aspirate and Platelet Rich Plasma Is an Effective Alternative to Total Knee Arthroplasty for Patients with Moderate Knee Arthrosis

Background: Osteoarthrosis (OA) of the knee afflicts millions worldwide. Total Knee Arthroplasty (TKA) is common, but associated with substantial cost and morbidity. Prior studies of intra-articular injection of fat, bone marrow aspirate (BMA), and platelet rich plasma (PRP) have shown clinical benefit. We hypothesized that injection of autologous adipose tissue, BMA, and PRP would provide significant benefit for patients with moderate knee OA resulting in avoidance of total knee arthroplasty (TKA) in most, with discontinuance of NSAIDs and other drugs. Methods: 42 TKA candidate patients (47 knees) with moderate (Kellgren-Lawrence 2 and 3) knee OA who had failed conservative treatment had autologous adipose tissue, BMA, and PRP injection as an alternative to TKA in office using only local anesthetic. Patients had discontinuance of all nonsteroidal anti-inflammatory medicines (NSAIDs) and other analgesics, except acetaminophen, prior to treatment. Patients were evaluated with Knee injury and Osteoarthritis Outcome Score Physical Shortform (KOOS-PS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Single Assessment Numeric Evaluation (SANE) prior to treatment, and at 6 months, 1, and 2 years after treatment. Results: Follow up exceeded 80% at all time points. There were no significant adverse events. TKA was avoided in 97% at one and 86% at two years after treatment. Mean SANE, KOOS-PS, and WOMAC scores significantly improved at 6 months, 1, and 2 years post-treatment. WOMAC and SANE scores were higher at two versus one year post-treatment. Conclusions: Combined fat, BMA, and PRP injection is a safe and effective treatment for moderate knee OA, with reliable avoidance of TKA and possible continued improvement at two year follow-up.

Exosomes: roles and therapeutic potential in osteoarthritis

Exosomes participate in many physiological and pathological processes by regulating cell-cell communication, which are involved in numerous diseases, including osteoarthritis (OA). Exosomes are detectable in the human articular cavity and were observed to change with OA progression. Several joint cells, including chondrocytes, synovial fibroblasts, osteoblasts, and tenocytes, can produce and secrete exosomes that influence the biological effects of targeted cells. In addition, exosomes from stem cells can protect the OA joint from damage by promoting cartilage repair, inhibiting synovitis, and mediating subchondral bone remodeling. This review summarizes the roles and therapeutic potential of exosomes in OA and discusses the perspectives and challenges related to exosome-based treatment for OA patients in the future.

Autologous adipose tissue injection versus platelet-rich plasma (PRP) injection in the treatment of knee osteoarthritis: a randomized, controlled study - study protocol

Background

Knee osteoarthritis (OA) is a common, chronic, progressive and degenerative disease which affects patients’ quality of life and may cause disability and social isolation. OA is a huge economic burden for the patient and a large strain for the whole healthcare system. Articular cartilage has a small potential to repair, with progressively more clinicians emphasizing cellular therapy. Subcutaneous fat tissue in human body is a large reservoir of mesenchymal stem cells (MSCs) and is been harvested in minimally invasive, simple procedure. Up to date there is no prospective randomized controlled studies demonstrating effectiveness and role of adipose tissue injections in OA treatment. The purpose of this study is to assess functional and clinical changes among patients with symptomatic knee OA treated with intra-articular injections of autologous adipose tissue or platelet rich plasma (PRP) and to compare efficacy of both therapeutic methods.

Methods

This is a prospective, randomized, controlled study. Patients who meet inclusion criteria will be allocated to Fat Tissue group or PRP group randomly. Subjects will receive an intra articular injection with autologous adipose tissue and PRP respectively. Patients will be assessed five times: before treatment and 1, 3, 6 and 12 months after the treatment. The assessment consists of patient reported outcome measures (The Knee injury and Osteoarthritis Outcome Score, International Knee Documentation Committee 2000, the Western Ontario and McMaster Universities Osteoarthritis Index, the Health Questionnaire EQ- 5D- 5 L), three functional tests (The Timed Up and Go Test, The 5 Times Sit to Stand Test, The 10 m Walk Test) and Maximal Isometric Voluntary Contraction.

Discussion

This study protocol has several strengths and weaknesses. One of strongest point of this study is the wide, multidimensional functional assessment which will give a large amount of objective data. On the other hand, lack of blinding has to be considered as a risk of both subject and investigator bias.

Trial registration

name of registry: ClinicalTrials.gov, trial registration number: NCT04321629, retrospectively registered on date of registration.

Stem Cell Treatment for Knee Articular Cartilage Defects and Osteoarthritis

PURPOSE OF REVIEW

To review the current basic science and clinical literature on mesenchymal stem cell (MSC) therapy for articular cartilage defects and osteoarthritis of the knee.

RECENT FINDINGS

MSCs derived from bone marrow, adipose, and umbilical tissue have the capacity for self-renewal and differentiation into the chondrocyte lineage. In theory, MSC therapy may help restore cartilage focally or diffusely where nascent regenerative potential in the intra-articular environment is limited. Over the last several years, in vitro and animal studies have elucidated the use of MSCs in isolation as injectables, in combination with biological delivery media and scaffolding, and as surgical adjuvants for cartilage regeneration and treatment of knee degenerative conditions. More recently, clinical and translational literature has grown more convincing from early descriptive case series to randomized controlled trials showing promise in efficacy and safety. Studies describing MSC for knee cartilage regeneration applications are numerous and varied in quality. Future research directions should include work on elucidating optimal cell concentration and dosing, as well as standardization in methodology and reporting in prospective trials. Backed by promise from in vitro and animal studies, preliminary clinical evidence on MSC therapy shows promise as a nonoperative therapeutic option or an adjuvant to existing surgical cartilage restoration techniques. While higher quality evidence to support MSC therapy has emerged over the last several years, further refinement of methodology will be necessary to support its routine clinical use.

Online Direct-to-Consumer Advertising of Stem Cell Therapy for Musculoskeletal Injury and Disease: Misinformation and Violation of Ethical and Legal Advertising Parameters

BACKGROUND

There has been a recent surge in health-care providers offering stem cell therapy (SCT) to patients with musculoskeletal disease. The purpose of this study was to identify and quantify the misinformation present in online direct-to-consumer (DTC) advertising of SCT targeting patients with musculoskeletal disease in the U.S. It was hypothesized that DTC advertising of SCT contains substantial misinformation.

METHODS

A list of keywords was used to identify web sites of practices advertising SCT directly to patients with musculoskeletal disease. Web sites were evaluated to determine the specialties of providers offering SCT, types of SCT being advertised, and misinformation presented. Categories of misinformation included false general claims, inaccurate statements regarding mechanism of action, unfounded results, and scare tactics.

RESULTS

Of the 896 practice web sites included in the analysis, 95.9% contained at least 1 statement of misinformation, with a mean of 4.65 ± 3.66 statements of misinformation among the sites. Practices associated with an orthopaedic surgeon provided 22% fewer statements of misinformation than practices without an orthopaedic surgeon when we controlled for the effects of other specialties. Practices associated with a podiatrist also provided 22% fewer statements of misinformation.

CONCLUSIONS

Nearly all practices failed to accurately represent the clinical efficacy of SCT in DTC advertising. While practices associated with an orthopaedic surgeon were less likely to provide misinformation, the majority of all web sites contained some type of misinformation, ranging from errors in the basic science of stem cells to outright false and misleading claims of their clinical effectiveness.

Bone Marrow Mesenchymal Stem Cell Therapy and Related Bone Marrow-Derived Orthobiologic Therapeutics

PURPOSE OF REVIEW

The purpose of the current article is to review the available literature related to bone marrow-derived mesenchymal stem cell therapy in the management of musculoskeletal pathologies and demonstrate the critical need for additional well-designed clinical studies.

RECENT FINDINGS

In recent years, there has been a rapid increase in interest regarding the use of bone marrow-derived mesenchymal stem cells in the treatment of musculoskeletal injury and disease. The clinical use of BM-MSCs and other forms of stem cell therapy has far outpaced the basic and translational science evidence required to elucidate the potential efficacy of this orthobiologic treatment approach. Early studies have demonstrated potential clinical benefit of utilizing bone marrow-derived mesenchymal stem cell therapy in the management of knee osteoarthritis, focal chondral lesions, shoulder pathology including rotator cuff tears and glenohumeral arthritis, and degenerative disk disease in the spine. To date, most published studies are small case series often lacking a control group or a standardized method of treatment. Bone marrow-derived mesenchymal stem cell therapy is becoming an increasingly common treatment for musculoskeletal injuries and disease. Although early clinical studies have shown promising outcomes, methodological flaws and lack of standardization among trials have limited the conclusions that can be drawn from the existing literature. A better understanding of the underlying mechanism of action and more carefully designed clinical trials will help reveal the efficacy and utility of BM-MSCs as a treatment modality for various orthopedic pathologies.

Articular Cartilage Regeneration in Osteoarthritis

There has been considerable advancement over the last few years in the treatment of osteoarthritis, common chronic disease and a major cause of disability in older adults. In this pathology, the entire joint is involved and the regeneration of articular cartilage still remains one of the main challenges, particularly in an actively inflammatory environment. The recent strategies for osteoarthritis treatment are based on the use of different therapeutic solutions such as cell and gene therapies and tissue engineering. In this review, we provide an overview of current regenerative strategies highlighting the pros and cons, challenges and opportunities, and we try to identify areas where future work should be focused in order to advance this field.