Treatment of knee osteoarthritis with intra-articular injection of autologous adipose-derived mesenchymal progenitor cells: a prospective, randomized, double-blind, active-controlled, phase IIb clinical trial

Adipose-derived mesenchymal stromal cells in clinical trials: Insights from single-cell studies

Mesenchymal Stromal Cells (MSCs) offer tremendous potential for the treatment of various diseases and their healing properties have been explored in hundreds of clinical trials. These trails primarily focus on immunological and neurological disorders, as well as regenerative medicine. Adipose tissue is a rich source of mesenchymal stromal cells and methods to obtain and culture adipose-derived MSCs (AD-MSCs) have been well established. Promising results from pre-clinical testing of AD-MSCs activity prompted clinical trials that further led to the approval of AD-MSCs for the treatment of complex perianal fistulas in Crohn's disease and subcutaneous tissue defects. However, AD-MSC heterogeneity along with various manufacturing protocols or different strategies to boost their activity create the need for standardized quality control procedures and safety assessment of the intended cell product. High-resolution transcriptomic methods have been recently gaining attention, as they deliver insight into gene expression profiles of individual cells, helping to deconstruct cellular hierarchy and differentiation trajectories, and to understand cell-cell interactions within tissues. This article presents a comprehensive overview of completed clinical trials evaluating the safety and efficacy of AD-MSC treatment, together with current single-cell studies of human AD-MSC. Furthermore, our work emphasizes the increasing significance of single-cell research in elucidating the mechanisms of cellular action and predicting their therapeutic effects.

Delivering Microrobots in the Musculoskeletal System

Disorders of the musculoskeletal system are the major contributors to the global burden of disease and current treatments show limited efficacy. Patients often suffer chronic pain and might eventually have to undergo end-stage surgery. Therefore, future treatments should focus on early detection and intervention of regional lesions. Microrobots have been gradually used in organisms due to their advantages of intelligent, precise and minimally invasive targeted delivery. Through the combination of control and imaging systems, microrobots with good biosafety can be delivered to the desired area for treatment. In the musculoskeletal system, microrobots are mainly utilized to transport stem cells/drugs or to remove hazardous substances from the body. Compared to traditional biomaterial and tissue engineering strategies, active motion improves the efficiency and penetration of local targeting of cells/drugs. This review discusses the frontier applications of microrobotic systems in different tissues of the musculoskeletal system. We summarize the challenges and barriers that hinder clinical translation by evaluating the characteristics of different microrobots and finally point out the future direction of microrobots in the musculoskeletal system.

Comparative single-cell transcriptional and proteomic atlas of clinical-grade injectable mesenchymal source tissues

Bone marrow aspirate concentrate (BMAC) and adipose-derived stromal vascular fraction (ADSVF) are the most marketed stem cell therapies to treat a variety of conditions in the general population and elite athletes. Both tissues have been used interchangeably clinically even though their detailed composition, heterogeneity, and mechanisms of action have neither been rigorously inventoried nor compared. This lack of information has prevented investigations into ideal dosages and has facilitated anecdata and misinformation. Here, we analyzed single-cell transcriptomes, proteomes, and flow cytometry profiles from paired clinical-grade BMAC and ADSVF. This comparative transcriptional atlas challenges the prevalent notion that there is one therapeutic cell type present in both tissues. We also provide data of surface markers that may enable isolation and investigation of cell (sub)populations. Furthermore, the proteome atlas highlights intertissue and interpatient heterogeneity of injected proteins with potentially regenerative or immunomodulatory capacities. An interactive webtool is available online.

Efficacy and safety of culture-expanded mesenchymal stromal cell therapy in the treatment of 4 types of inflammatory arthritis: A systematic review and meta-analysis of 36 randomized controlled trials

OBJECTIVE

This study aims to assess the effectiveness and safety of mesenchymal stem cell (MSC) transplantation in the treatment of inflammatory arthritis.

METHODS

Two researchers conducted a comprehensive search of Chinese and English databases from their inception until July 2023. The literature screening and data extraction were then performed. Statistical analysis was carried out using RevMan 5.4 software.

RESULTS

A total of 36 relevant RCTs, involving 2,076 participants, were ultimately included in this study. These RCTs encompassed four types of inflammatory arthritis, namely rheumatoid arthritis (RA), osteoarthritis (OA), ankylosing spondylitis (AS), and systemic sclerosis (SSc). The results demonstrated that MSC therapy exhibited improvements in the Visual Analog Scale (VAS) for pain in OA patients (bone marrow: SMD=-0.95, 95 % CI: -1.55 to -0.36, P = 0.002; umbilical cord: SMD=-2.03, 95 % CI: -2.99 to -1.07, P < 0.0001; adipose tissue: SMD=-1.26, 95 % CI: -1.99 to -0.52, P = 0.0009). Specifically, MSCs sourced from adipose tissue showed enhancements in Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain (P = 0.0001), WOMAC physical function (P = 0.001), and total WOMAC scores (P = 0.0003). As for MSC therapy in RA, AS, and SSc, the current systematic review suggests a potential therapeutic effect of MSCs on these inflammatory arthritic conditions. Safety assessments indicated that MSC therapy did not increase the incidence of adverse events.

CONCLUSION

MSCs have the potential to alleviate joint pain and improve joint function in patients with inflammatory arthritis. Moreover, MSC therapy appears to be relatively safe and could be considered as a viable alternative treatment option for inflammatory arthritis.

Transplantation of three mesenchymal stem cells for knee osteoarthritis, which cell and type are more beneficial? a systematic review and network meta-analysis

BACKGROUND

In knee osteoarthritis (KOA), treatments involving knee injections of bone marrow-derived mesenchymal stem cells (BM-MSC), adipose tissue-derived mesenchymal stem cells (AD-MSC), or umbilical cord-derived mesenchymal stem cells (UC-MSC) have shown promise in alleviating symptoms. However, which types of mesenchymal stem cells (MSCs) have the best therapeutic outcomes remain uncertain.

METHOD

We systematically searched PubMed, OVID, Web of Science, and the Cochrane Library until January 1, 2024. The study evaluated five endpoints: Visual Analog Score (VAS) for Pain, Range of Motion (ROM), Whole-Organ Magnetic Resonance Imaging Score (WORMS), Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), and adverse events (ADs). Standard meta-analysis and network meta-analysis were performed using Stata 16.0.

RESULTS

Fifteen studies involving 585 patients were included in the meta-analysis. Standard meta-analysis revealed significant improvements with MSCs in VAS score (P < 0.001), knee ROM (P < 0.001), and WOMAC (P < 0.016) compared to traditional therapy. In the network meta-analysis, autologous MSCs significantly improved VAS score [SMD = 2.94, 95% CI (1.90, 4.56)] and knee ROM [SMD = 0.26, 95% CI (0.08, 0.82)] compared to traditional therapy. Similarly, BM-MSC significantly improved VAS score [SMD = 0.31, 95% CI (0.11, 0.91)] and knee ROM [SMD = 0.26, 95% CI (0.08, 0.82)] compared to hyaluronic acid. However, compared with traditional therapy, autologous or allogeneic MSCs were associated with more adverse reactions [SMD = 0.11, 95% CI (0.02, 0.59)], [SMD = 0.13, 95% CI (0.002, 0.72)]. Based on the surface under the cumulative ranking results, autologous BM-MSC showed the most improvement in ROM and pain relief in KOA patients, UC-MSC (SUCRA 94.1%) were most effective for positive WORMS, and AD-MSC (SUCRA 70.6%) were most effective for WOMAC-positive patients.

CONCLUSION

MSCs transplantation effectively treats KOA patients, with autologous BM-MSC potentially offering more excellent benefits.

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.

Relative efficacy and safety of mesenchymal stem cells for osteoarthritis: a systematic review and meta-analysis of randomized controlled trials

Introduction

The aim of this meta-analysis was to evaluate the efficacy and safety of mesenchymal stem cells (MSCs) for the treatment of knee osteoarthritis (OA).

Methods

The PubMed, Embase, Cochrane Central Register of Controlled Trials, Scopus and Web of Science databases were searched from inception to May 6, 2024 to identify randomized controlled trials that compared MSCs and placebo or other nonsurgical approaches for treating OA. Two investigators independently searched the literature and extracted data, and conventional meta-analyses were conducted with Review Manager 5.3. The outcomes included pain relief, functional improvement, and risk of adverse events (AEs).

Results

A total of 18 articles were included. Overall, MSCs were superior to placebo in terms of relieving pain and improving function at the 12-month follow-up. However, the differences in treatment-related AEs were not significant.

Conclusion

MSCs may relieving pain and improving function of OA. The limitations of this study include the high heterogeneity of the included studies. Additionally, the follow-up time in the included studies was relatively short, so more clinical trials are needed to predict the long-term efficacy and safety of MSCs.

Systematic review registration

https://doi.org/10.17605/OSF.IO/5BT6E, identifier CRD42022354824.

Effects of Adipose-derived Stem Cells in the Treatment of Knee Osteoarthritis: A Case Report in Brazil's Unified Health System

Osteoarthritis (OA) can incapacitate the individual to perform their activities of daily living due to pain. This is an important public health issue that worsens worldwide and in Brazil, since the population goes through an aging process, and has caused increased public spending on the monitoring and maintenance of treatments that can last for years and still not be resolutive. Thus, the search for innovative and effective therapies that can reduce costs becomes necessary. In this context, the present study reports the first application of cell therapy with adipose-derived stem cells in the treatment of cases of OA that are refractory to the conservative treatment, performed in the Brazilian Unified Health System (Sistema Único de Saúde, SUS). The evaluation was performed with the application of the Visual Analog Scale (VAS), the Short Form Health Survey (SF-36) and the Western Ontario and McMaster Universities (WOMAC), specifics for OA evaluation, and also an analysis of the synovial fluid (inflammatory cytokines). The cell therapy improved the scores on the WOMAC, SF-36 and EVA, and reduced the inflammatory process. We observed a decrease of 0.73x in the TNF, of 0,71x in IL-1b, of 0,68x in IL-8, and of 0,70x in IL-10. For IL-6, an increase of 1,48x was observed. Therefore, this cell therapy can be considered promising in aiding the management of this disease, since it improved the patient's pain, decrease inflammatory markers, and enabled the return to activities of daily living, which resulted in an improvement in their quality of life.

High efficiency protocol for platelet derived fibrin gel loaded with mesenchymal stromal cells extracellular vesicles

Introduction

Extracellular vesicles from mesenchymal stromal cells (MSC-EVs) are potent stimulators of naïve cartilage and their injection is studied in clinical trials for cartilage lesions, since often cartilage repaired with conventional approaches is incomplete or less performant leading to joint degeneration. The main pitfall of these innovative approaches is the high EVs dispersion into the joint cavity and consequent low concentration at lesion site. Thus, biological scaffolds for concentration of EVs where needed might be a promising option. This work aimed at producing an enhanced platelet-derived fibrin gel loaded with adipose-derived MSCs (ASCs)-EVs.

Methods

EVs' embedment efficiency in platelet gel, their release and incorporation in OA chondrocytes and cartilage explants were monitored by flow cytometry, microfluidic approaches, scansion electron microscopy and real-time quantitative multimodal nonlinear optics imaging. The effect of released EVs was tested in OA chondrocytes by gene expression studies.

Results

A protocol ensuring high incorporation EVs efficiency in platelet gels was defined, relying on a one-step modification of the standard procedure used in current clinical practice. Trapped EVs were released continuously for up to 4 weeks and uptaken in pathologic chondrocytes and cartilage explants. The release of the EVs-loaded platelet gel had stronger and synergic anti-inflammatory/matrix remodelling effects with respect to both EVs per se and unloaded gel released products.

Conclusions

These results suggest the feasibility of producing a platelet gel loaded with MSC-EVs at high efficiency that can be used as an enhanced tool to foster chondrocyte homeostasis, a key requisite for proper cartilage healing.

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.

Impaired Remodeling of White Adipose Tissue in Obesity and Aging: From Defective Adipogenesis to Adipose Organ Dysfunction

The adipose organ adapts and responds to internal and environmental stimuli by remodeling both its cellular and extracellular components. Under conditions of energy surplus, the subcutaneous white adipose tissue (WAT) is capable of expanding through the enlargement of existing adipocytes (hypertrophy), followed by de novo adipogenesis (hyperplasia), which is impaired in hypertrophic obesity. However, an impaired hyperplastic response may result from various defects in adipogenesis, leading to different WAT features and metabolic consequences, as discussed here by reviewing the results of the studies in animal models with either overexpression or knockdown of the main molecular regulators of the two steps of the adipogenesis process. Moreover, impaired WAT remodeling with aging has been associated with various age-related conditions and reduced lifespan expectancy. Here, we delve into the latest advancements in comprehending the molecular and cellular processes underlying age-related changes in WAT function, their involvement in common aging pathologies, and their potential as therapeutic targets to influence both the health of elderly people and longevity. Overall, this review aims to encourage research on the mechanisms of WAT maladaptation common to conditions of both excessive and insufficient fat tissue. The goal is to devise adipocyte-targeted therapies that are effective against both obesity- and age-related disorders.

Identification of therapeutic targets in osteoarthritis by combining heterogeneous transcriptional datasets, drug-induced expression profiles, and known drug-target interactions

BACKGROUND

Osteoarthritis (OA) is a multifactorial, hypertrophic, and degenerative condition involving the whole joint and affecting a high percentage of middle-aged people. It is due to a combination of factors, although the pivotal mechanisms underlying the disease are still obscure. Moreover, current treatments are still poorly effective, and patients experience a painful and degenerative disease course.

METHODS

We used an integrative approach that led us to extract a consensus signature from a meta-analysis of three different OA cohorts. We performed a network-based drug prioritization to detect the most relevant drugs targeting these genes and validated in vitro the most promising candidates. We also proposed a risk score based on a minimal set of genes to predict the OA clinical stage from RNA-Seq data.

RESULTS

We derived a consensus signature of 44 genes that we validated on an independent dataset. Using network analysis, we identified Resveratrol, Tenoxicam, Benzbromarone, Pirinixic Acid, and Mesalazine as putative drugs of interest for therapeutics in OA for anti-inflammatory properties. We also derived a list of seven gene-targets validated with functional RT-qPCR assays, confirming the in silico predictions. Finally, we identified a predictive subset of genes composed of DNER, TNFSF11, THBS3, LOXL3, TSPAN2, DYSF, ASPN and HTRA1 to compute the patient's risk score. We validated this risk score on an independent dataset with a high AUC (0.875) and compared it with the same approach computed using the entire consensus signature (AUC 0.922).

CONCLUSIONS

The consensus signature highlights crucial mechanisms for disease progression. Moreover, these genes were associated with several candidate drugs that could represent potential innovative therapeutics. Furthermore, the patient's risk scores can be used in clinical settings.

Protecting the regenerative environment: selecting the optimal delivery vehicle for cartilage repair-a narrative review

Focal cartilage defects are common in youth and older adults, cause significant morbidity and constitute a major risk factor for developing osteoarthritis (OA). OA is the most common musculoskeletal (MSK) disease worldwide, resulting in pain, stiffness, loss of function, and is currently irreversible. Research into the optimal regenerative approach and methods in the setting of either focal cartilage defects and/or OA holds to the ideal of resolving both diseases. The two fundamentals required for cartilage regenerative treatment are 1) the biological element contributing to the regeneration (e.g., direct application of stem cells, or of an exogenous secretome), and 2) the vehicle by which the biological element is suspended and delivered. The vehicle provides support to the regenerative process by providing a protective environment, a structure that allows cell adherence and migration, and a source of growth and regenerative factors that can activate and sustain regeneration. Models of cartilage diseases include osteochondral defect (OCD) (which usually involve one focal lesion), or OA (which involves a more diffuse articular cartilage loss). Given the differing nature of these models, the optimal regenerative strategy to treat different cartilage diseases may not be universal. This could potentially impact the translatability of a successful approach in one condition to that of the other. An analogy would be the repair of a pothole (OCD) versus repaving the entire road (OA). In this narrative review, we explore the existing literature evaluating cartilage regeneration approaches for OCD and OA in animal then in human studies and the vehicles used for each of these two conditions. We then highlight strengths and challenges faced by the different approaches presented and discuss what might constitute the optimal cartilage regenerative delivery vehicle for clinical cartilage regeneration.

Autologous microfragmented adipose tissue treatment of knee osteoarthritis demonstrates effectiveness in 68% of patients at 4-year follow-up

BACKGROUND

Adipose tissue-derived stem cells are an interesting therapeutic option for early knee osteoarthritis (OA) treatment due to their high plasticity, easiness of harvesting and rapidity of administration. The aim of this study was to evaluate the medium-term effectiveness and safety of Microfragmented Autologous Fat Tissue (MFAT) injection treatment at 4-year follow-up and to investigate potential correlations among patients' pre-treatment clinical condition and clinical outcomes to identify possible predicting factors for procedure success or failure.

PATIENTS AND METHODS

This is a prospective trial enrolling 46 patients with diagnosis of symptomatic knee OA and failure of previous conservative measures who underwent diagnostic arthroscopy and single autologous MFAT injection between June 2017 and July 2018. Patients were assessed with repeated clinical scoring systems at baseline, 6 months, 1 and 4 years after surgery. The evaluation included demographic characteristics, arthroscopic findings, and stem cell number from injected tissue.

RESULTS

No major complications were reported during follow-up period and there was a significant increase of Lysholm knee score from baseline value of 61.7 ± 13.8 to 79.5 ± 16.9 at 4 years (p < 0.001). The WOMAC score increased from a baseline value of 66.5 ± 14.7 to 82.8 ± 15.7 at 4 years (p < 0.001) and there was a significant decrease of VAS pain score from baseline value of 6.3 ± 1.5 to 3.5 ± 2.6 at 4-year follow-up (p < 0.001). ROM improved significantly from 118.4 ± 2.6 to 122.5 ± 2.5 at 12 months (p < 0.001), but did not improve at 4 years (p > 0.05). 15 patients (32.6%) were considered treatment failures, because they required secondary surgery, further injection therapy or experienced symptoms persistence. Patient with synovitis had 75% failure rate, although synovitis did not result as a statistically significant factor influencing clinical outcome up to 4-year follow-up (p = 0.058). Age, cartilage defects severity, BMI, concomitant procedures, and stem cell number from injected MFAT did not show any significant correlation with the results.

CONCLUSIONS

MFAT intra-articular injection is a safe procedure with positive improvements up to 4-year follow-up in patients with early knee OA. These findings suggest MFAT could be a minimally invasive treatment of early knee OA with durable benefits at mid-term evaluation.

TRIAL REGISTRATION

IRB number ID-3522.

Exploring Orthopedic Stem-Cell Approaches for Osteoarthritis Management: Current Trends and Future Horizons

PURPOSE OF REVIEW

Osteoarthritis (OA) is a prevalent and debilitating condition characterized by joint degeneration and pain. Current treatment options aim to alleviate symptoms and slow disease progression but lack curative potential. Stem cell therapies have emerged as a promising alternative. This article explores the epidemiology, pathophysiology, clinical manifestations of hip and knee OA, and the evolving role of stem cell therapies in their treatment.

RECENT FINDINGS

The global prevalence of OA, with knee OA being the most common form, has fueled the demand for stem cell therapies. Despite limited robust evidence supporting their efficacy, clinical trials investigating stem-cell treatments for OA have reported encouraging radiological and clinical improvements. Stem cell therapies offer potential disease-modifying benefits through immunomodulatory actions, growth factor secretion, and chondrogenic capabilities. Adipose-derived mesenchymal stem cells (ADMSCs) have shown promise in clinical trials for OA treatment, offering potential pain relief and functional improvement. ADMSCs possess advantages such as accessibility and a favorable safety profile, making them a viable option for OA management. Although other stem-cell types, including human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs), have been used in OA treatment, ADMSCs have demonstrated superior outcomes. By providing a comprehensive overview of the evolving landscape of stem cell therapies for hip and knee OA, this article highlights the potential of stem-cell treatments to address the limitations of current therapies. However, further research is required to establish their long-term efficacy, identify optimal stem-cell types, and develop standardized protocols.

Safety and Tolerability of Intra-Articular Injection of Adipose-Derived Mesenchymal Stem Cells GXCPC1 in 11 Subjects With Knee Osteoarthritis: A Nonrandomized Pilot Study Without a Control Arm

The current study aimed to determine the safety profile of intra-articular-injected allogeneic adipose-derived mesenchymal stem cells (ADSCs) GXCPC1 in subjects with knee osteoarthritis (OA) and its preliminary efficacy outcome. The 3 + 3 phase I study was designed with two dose-escalation cohorts: low dose (6.7 × 106 GXCPC1, N = 5) and high dose (4 × 107 GXCPC1, N = 6). The primary endpoint was safety, which was evaluated by recording adverse events throughout the trial; the secondary endpoints included total, pain, stiffness, and function subscales of the Western Ontario and McMaster Universities Arthritis Index (WOMAC), Visual Analogue Scale (VAS) for pain, and 12-Item Short Form (SF-12) health survey questionnaire. The GXCPC1 treatment was found to be safe after 1 year of follow-up with no treatment-related severe adverse events observed. When compared to baseline, subjects in both the low- and high-dose cohorts demonstrated improving trends in pain and knee function after receiving GXCPC1 treatment. Generally, the net change in pain (95% confidence interval (CI) = -7.773 to -2.561t at 12 weeks compared to baseline) and knee function (95% CI = -24.297 to -10.036t at 12 weeks compared to baseline) was better in subjects receiving high-dose GXCPC1. Although this study included a limited number of subjects without a placebo arm, it showed that the intra-articular injection of ADSCs was safe and well-tolerated in subjects with therapeutic alternatives to treat knee OA. However, a larger scale study with an appropriate control would be necessary for clinical efficacy in the following study.

Engineered stem cell-based strategy: A new paradigm of next-generation stem cell product in regenerative medicine

Stem cells have garnered significant attention in regenerative medicine owing to their abilities of multi-directional differentiation and self-renewal. Despite these encouraging results, the market for stem cell products yields limited, which is largely due to the challenges faced to the safety and viability of stem cells in vivo. Besides, the fate of cells re-infusion into the body unknown is also a major obstacle to stem cell therapy. Actually, both the functional protection and the fate tracking of stem cells are essential in tissue homeostasis, repair, and regeneration. Recent studies have utilized cell engineering techniques to modify stem cells for enhancing their treatment efficiency or imparting them with novel biological capabilities, in which advances demonstrate the immense potential of engineered cell therapy. In this review, we proposed that the "engineered stem cells" are expected to represent the next generation of stem cell therapies and reviewed recent progress in this area. We also discussed potential applications of engineered stem cells and highlighted the most common challenges that must be addressed. Overall, this review has important guiding significance for the future design of new paradigms of stem cell products to improve their therapeutic efficacy.

Advanced Therapeutic Medicinal Products in Bone and Cartilage Defects

The number of patients with functional loss of bone and cartilage tissue has shown an increasing trend. Insufficient or inappropriate conventional treatments applied for trauma, orthopedic diseases, or other bone and cartilage-related disorders can lead to bone and cartilage damage. This represents a worldwide public health issue and a significant economic burden. Advanced therapeutic medicinal products (ATMPs) proposed promising alternative therapeutic modalities by application of cell-based and tissue engineering approaches. Recently, several ATMPs have been developed to promote bone and cartilage tissue regeneration. Fifteen ATMPs, two related to bone and 13 related to cartilage, have received regulatory approval and marketing authorization. However, four ATMPs were withdrawn from the market for various reasons. However, ATMPs that are still on the market have demonstrated positive results, their broad application faced limitations. The development and standardization of methodologies will be a major challenge in the coming decades. Currently, the number of ATMPs in clinical trials using mesenchymal stromal cells or chondrocytes indicates a growing recognition that current ATMPs can be improved. Research on bone and cartilage tissue regeneration continues to expand. Cell-based therapies are likely to be clinically supported by the new ATMPs, innovative fabrication processes, and enhanced surgical approaches. In this study, we highlighted the available ATMPs that have been used in bone and cartilage defects and discussed their advantages and disadvantages in clinical applications.

The Therapeutic Potential of Pericytes in Bone Tissue Regeneration

Pericytes, as perivascular cells, are present in all vascularized organs and tissues, and they actively interact with endothelial cells in capillaries and microvessels. Their involvement includes functions like blood pressure regulation, tissue regeneration, and scarring. Studies have confirmed that pericytes play a crucial role in bone tissue regeneration through direct osteodifferentiation processes, paracrine actions, and vascularization. Recent preclinical and clinical experiments have shown that combining perivascular cells with osteogenic factors and tissue-engineered scaffolds can be therapeutically effective in restoring bone defects. This approach holds promise for addressing bone-related medical conditions. In this review, we have emphasized the characteristics of pericytes and their involvement in angiogenesis and osteogenesis. Furthermore, we have explored recent advancements in the use of pericytes in preclinical and clinical investigations, indicating their potential as a therapeutic resource in clinical applications.

Knee Osteoarthritis: Clinical and MRI Outcomes After Multiple Intra-Articular Injections With Expanded Autologous Adipose-Derived Stromal Cells or Platelet-Rich Plasma

OBJECTIVE

To directly compare clinical and MRI outcomes of multiple intra-articular injections of adipose-derived stromal cells (ASCs) or platelet-rich plasma (PRP) in patients with knee osteoarthritis (OA).

DESIGN

We retrospectively compared 24-month outcomes in (1) 27 patients receiving 3-monthly intra-articular injections with a total of 43.8 million ASCs and (2) 23 patients receiving 3-monthly injections of 3-ml preparation of PRP. All patients had Kellgren-Lawrence grade 1, 2, or 3 knee OA with failed conservative medical therapy. The Numeric Pain Rating Scale (NPRS) scores; Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline, 6, 12, and 24 months after the first injection; and the MRI Osteoarthritis Knee Score (MOAKS) at 12 and 24 months were considered as outcomes.

RESULTS

No major complications occurred in any patient. Both groups significantly improved in pain NPRS score and KOOS at 6 months. At 12- and 24-month evaluations, the ASC group significantly decreased scores to a greater degree (P < 0.001) than the PRP group. MOAKS scores indicated a decrease in disease progression in the ASC group.

CONCLUSION

Both ASCs and PRP were safe and resulted in clinical improvement in patients with knee OA at 6 months; however, at 12 and 24 months, ASCs outperformed leukocyte-poor PRP in clinical and radiological outcomes.

Application of human platelet lysate in chondrocyte expansion promotes chondrogenic phenotype and slows senescence progression via BMP-TAK1-p38 pathway

Osteoarthritis (OA) is one of the most common musculoskeletal degenerative. OA treatments are aiming to slow down disease progression; however, lack of cartilage regeneration efficacy. Autologous chondrocyte implantation (ACI) is a promising cartilage-regeneration strategy that uses human articular chondrocytes (HACs) as cellular materials. However, the unreadiness of HACs from prolonged expansion, cellular senescence, and chondrogenic dedifferentiation occurred during conventional expansion, thus, minimizing the clinical efficacy of ACI. We aimed to examine the effects of a human platelet lysate (HPL) as an alternative human-derived HAC medium supplement to overcome the limitations of conventional expansion, and to explain the mechanism underlying the effects of HPL. During passages 2-4 (P2-P4), HPL significantly increased HAC proliferation capacities and upregulated chondrogenic markers. Simultaneously, HPL significantly reduced HAC senescence compared with conventional condition. HACs treated with LDN193189 exhibited a reduction in proliferation capacity and chondrogenic marker expression, whereas the HAC senescence increased slightly. These findings indicated involvement of BMP-2 signaling transduction in the growth-assistive, anti-senescent, and chondrogenic-inductive properties of HPL, which demonstrated its beneficial effects for application as HAC medium supplement to overcome current expansion limitations. Finally, our findings support the roles of platelets in platelet-rich plasma as a promising treatment for patients with OA.

Current Progress in Stem Cell Therapy for Male Infertility

Infertility has become one of the most common issues worldwide, which has negatively affected society and infertile couples. Meanwhile, male infertility is responsible for about 50% of infertility. Accordingly, a great number of researchers have focused on its treatment during the last few years; however, current therapies such as assisted reproductive technology (ART) are not effective enough in treating male infertility. Because of their self-renewal and differentiation capabilities and unlimited sources, stem cells have recently raised great hope in the treatment of reproductive system disorders. Stem cells are undifferentiated cells that can induce different numbers of specific cells, such as male and female gametes, demonstrating their potential application in the treatment of infertility. The present review aimed at identifying the causes and potential factors that influence male fertility. Besides, we highlighted the recent studies that investigated the efficiency of stem cells such as spermatogonial stem cells (SSCs), embryonic stem cells (ESCs), very small embryonic-like stem cells (VSELs), induced pluripotent stem cells (iPSCs), and mesenchymal stem cells (MSCs) in the treatment of various types of male infertility.

What is the optimal dose of adipose-derived mesenchymal stem cells treatment for knee osteoarthritis? A conventional and network meta-analysis of randomized controlled trials

BACKGROUND

Despite increasing clinical investigations underscoring the efficacy and safety of adipose-derived mesenchymal stem cells (AD-MSCs) therapy in knee osteoarthritis (KOA), no article has recently reviewed the cell dosage. This study aimed to evaluate the efficacy and safety of varying doses of AD-MSCs in treating KOA using conventional and network meta-analysis.

METHODS

A search of databases in in Chinese and English was performed to identify randomized controlled trials (RCT) on MSCs for knee osteoarthritis from the inception date to May 1, 2022. This study mainly analyzed the efficacy of AD-MSCs in the treatment of KOA, and subgroup analysis was performed on the therapeutic effects of MSCs from different tissues at the same dose. We divided the different cell doses into low, moderate, and high groups, with the corresponding cell doses: (0-25)*10^6, (25-50)*10^6, and > 50*10^6 cells, respectively. We further analyzed the improvement of improvement of the Visual Analog Scale (VAS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores and the incidence of adverse events (AEs) after varied dosage injection.

RESULTS

A total of 16 literatures were included in this study, of which 8 literatures were about AD-MSCs. Conventional meta-analysis suggests that AD-MSCs can reduce pain and improve function in KOA patients, regardless of the cell doses, up to 12 months of follow-up. The network meta-analysis showed that intra-articular injection of AD-MSCs significantly improved pain and knee function scores in KOA patients compared with the control group at 3, 6, and 12 months. Among the three groups, the high-dose group had the best treatment effect, and the degree of joint pain and dysfunction indicators improved more significantly in the early stage. For adverse events, there was a dose-response trend that increased with increasing doses.

CONCLUSIONS

Both cell doses reduced pain and improved knee function in KOA patients. The effect surpassed in the high-dose group than in the moderate-dose, low-dose and control groups. However, adverse events also increase with the increase in dose, which should be carefully considered in clinical application, and the side effects still need to be paid attention to. Considering the limitations of this meta-analysis, future studies need to further explore the efficacy and safety of different doses of treatment, and carry out large sample, multi-center, randomized controlled trials to ensure the reliability and promotion value of the research results.

Long-term and sequential treatment for osteoporosis

Osteoporosis is a skeletal disorder that causes impairment of bone structure and strength, leading to a progressively increased risk of fragility fractures. The global prevalence of osteoporosis is increasing in the ageing population. Owing to the chronic character of osteoporosis, years or even decades of preventive measures or therapy are required. The long-term use of bone-specific pharmacological treatment options, including antiresorptive and/or osteoanabolic approaches, has raised concerns around adverse effects or potential rebound phenomena after treatment discontinuation. Imaging options, risk scores and the assessment of bone turnover during initiation and monitoring of such therapies could help to inform individualized treatment strategies. Combination therapies are currently used less often than 'sequential' treatments. However, all patients with osteoporosis, including those with secondary and rare causes of osteoporosis, as well as specific patient populations (for example, young adults, men and pregnant women) require new approaches for long-term therapy and disease monitoring. New pathophysiological aspects of bone metabolism might therefore help to inform and revolutionize the diagnosis and treatment of osteoporosis.

Effect of intra-knee injection of autologous adipose stem cells or mesenchymal vascular components on short-term outcomes in patients with knee osteoarthritis: an updated meta-analysis of randomized controlled trials

OBJECTIVE

Assess the efficacy of single and multiple intra-articular injections of autologous adipose-derived stem cells (ASCs) and adipose-derived stromal vascular fraction (ADSVF) for the treatment of knee osteoarthritis (OA).

METHODS

We conducted a thorough and systematic search of several databases, including PubMed, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov, to identify relevant studies. The included studies were randomized controlled trials (RCTs) that involved single or multiple intra-articular injections of autologous ASCs or ADSVF for the treatment of patients with knee osteoarthritis, without any additional treatment, and compared to either placebo or hyaluronic acid.

RESULTS

A total of seven RCTs were analyzed in this study. The results of the meta-analysis show that compared to the control group, both single and multiple intra-articular injections of ASCs or ADSVF demonstrated superior pain relief in the short term (Z = 3.10; P < 0.0001 and Z = 4.66; P < 0.00001) and significantly improved function (Z = 2.61; P < 0.009 and Z = 2.80; P = 0.005). Furthermore, MRI assessment showed a significant improvement in cartilage condition compared to the control group. (Z = 8.14; P < 0.000001 and Z = 5.58; P < 0.00001).

CONCLUSIONS

In conclusion, in osteoarthritis of the knee, single or multiple intra-articular injections of autologous ASCs or ADSVF have shown significant pain improvement and safety in the short term in the absence of adjuvant therapy. Significant improvements in cartilage status were also shown. A larger sample size of randomized controlled trials is needed for direct comparison of the difference in effect between single and multiple injections.

Adipose Tissue-Derived Products May Present Inflammatory Properties That Affect Chondrocytes and Synoviocytes from Patients with Knee Osteoarthritis

Adipose tissue-derived cell-based injectable therapies have been demonstrated to have disease-modifying effects on joint tissues in preclinical studies on animal osteoarthritis (OA) models, but clinical results are heterogeneous and not always satisfactory. The aim of this study was to investigate the influence of adipose tissue properties on the therapeutic effects of the adipose-derived product in an in vitro OA setting. Micro-fragmented adipose tissue (MF-AT) samples were obtained from 21 OA patients (mean age 51.7 ± 11.8 years, mean BMI 25.7 ± 4.1 kg/m2). The analysis of the MF-AT supernatant was performed to analyze the release of inflammatory factors. The effects of MF-AT inflammatory factors were investigated on chondrocytes and synoviocytes gene expression levels. Patients' characteristics were analyzed to explore their influence on MF-AT inflammatory molecules and on the MF-AT effects on the gene expression of chondrocytes and synoviocytes. The study results demonstrated that adipose tissue-derived products may present inflammatory properties that influence the therapeutic potential for OA treatment, with products with a higher pro-inflammatory profile stimulating a higher expression of genes related to a more inflamed and catabolic phenotype. A higher pro-inflammatory cytokine pattern and a higher pro-inflammatory effect were found in adipose tissue-derived products obtained from OA patients with higher BMI.

A Worldwide Analysis of Adipose-Derived Stem Cells and Stromal Vascular Fraction in Orthopedics: Current Evidence and Applications

The biological enhancement of tissue regeneration and healing is an appealing perspective in orthopedics. We aimed to conduct a systematic review to describe the global distribution of studies investigating the use of adipose tissue derivates in orthopedics and to provide information on their quality and on the products available. The quality of the included studies was assessed using the modified Coleman Methodology Score (mCMS) and the Cochrane risk-of-bias tool for randomized trials. Eighty-two studies were included, with a total of 3594 patients treated. In total, 70% of the studies investigated the treatment of knee disorders, predominantly osteoarthritis; 26% of all studies dealt with expanded adipose-derived stem/stromal cells (ADSCs), 72% of which had stromal vascular fraction (SVF); 70% described the injection of adipose tissue derivates into the affected site; and 24% described arthroscopies with the addition of adipose tissue derivates. The mean mCMS for all studies was 51.7 ± 21.4 points, with a significantly higher score for the studies dealing with expanded ADSCs compared to those dealing with SVF (p = 0.0027). Our analysis shows high heterogeneity in terms of the types of performed procedures as well as the choice and processing of adipose tissue derivates.

Clinical Efficacy and Safety of the Intra-articular Injection of Autologous Adipose-Derived Mesenchymal Stem Cells for Knee Osteoarthritis: A Phase III, Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Intra-articular injection of autologous culture-expanded adipose-derived mesenchymal stem cells (ADMSCs) has introduced a promising treatment option for knee osteoarthritis. Although the clinical efficacy and safety of ADMSCs have been reported, the treatment remains controversial owing to the small sample sizes and heterogeneous osteoarthritis grades in previous studies.

PURPOSE

To assess the efficacy and safety of intra-articular injection of ADMSCs as compared with placebo in alleviating pain and improving functional capacity in a large sample of patients with knee osteoarthritis of Kellgren-Lawrence (K-L) grade 3.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

This phase III multicenter clinical trial was a double-blind randomized controlled study that included 261 patients with K-L grade 3 symptomatic knee osteoarthritis who were administered a single injection of autologous culture-expanded ADMSCs or placebo. Clinical data were assessed at baseline and at 3 and 6 months after the injection. The primary endpoints were improvements in 100-mm visual analog scale (VAS) for pain and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) for function at 6 months after the injection. The secondary endpoints included clinical and radiologic examinations and safety after injection. The changes in cartilage defects after injection were assessed by magnetic resonance imaging at 6 months.

RESULTS

The ADMSC and control groups included 125 and 127 patients available for follow-up, respectively. At 6 months, the ADMSC group showed significantly better improvements in 100-mm VAS (ADMSC vs control, 25.2 vs 15.5; P = .004) and total WOMAC score (21.7 vs 14.3; P = .002) as compared with the control group. The linear mixed model analysis indicated significantly better improvements in all clinical outcomes in the ADMSC group after 6 months. At 6 months, the ADMSC group achieved significantly higher proportions of patients above the minimal clinically important difference in 100-mm VAS and WOMAC score. Radiologic outcomes and adverse events did not demonstrate significant differences between the groups. No serious treatment-related adverse events were observed. Magnetic resonance imaging revealed no significant difference in change of cartilage defects between the groups at 6 months.

CONCLUSION

Intra-articular injection of autologous culture-expanded ADMSCs provided significant pain relief and functional improvements in patients with K-L grade 3 osteoarthritis. Long-term results are needed to determine the disease-modifying effects of ADMSCs, such as structural changes, and the duration of effect of intra-articular injection of ADMSCs in knee osteoarthritis.

REGISTRATION

NCT03990805 (ClinicalTrials.gov identifier).

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).

Mesenchymal stem cells can improve discogenic pain in patients with intervertebral disc degeneration: a systematic review and meta-analysis

Background: The meta-analysis aimed to estimate the efficacy of mesenchymal stem cells on lumbar discogenic pain in patients with intervertebral disc degeneration. Methods: A comprehensive literature search was conducted in the PubMed, Web of Science, Embase and Cochrane Library databases with predetermined search strategy up to 18 September 2022. The clinical studies focusing on evaluating the efficacy and safety of mesenchymal stem cells in patients with intervertebral disc degeneration were identified. The primary outcomes were changes of pain score and Oswestry Disability Index. The Newcastle-Ottawa Scale for cohort studies was used for quality assessment. Review Manager was used to conduct the statistical analysis. Pooled risk ratios were calculated based on the random effect model. Heterogeneity, subgroup, and publication bias analyses were also performed. Results: There were 2,392 studies were identified in the initial search, and 9 eligible studies with 245 patients were eventually included in this review. The Visual Analogue Scale score was significantly lower in patients after receiving mesenchymal stem cells therapy (mean difference = 41.62; 95% confidence interval 24.32 to 58.93; Heterogeneity: I² = 98%; p < 0.01). And the pooled mean difference of Oswestry Disability Index was 22.04 from baseline to final follow-up points (95% confidence interval 8.75 to 35.33; p = 0.001; Heterogeneity: I² = 98%; p < 0.001). The pooled reoperation proportion was 0.074 (95% confidence interval 0.009 to 0.175; Heterogeneity: I² = 72%; p < 0.01). There were no serious related adverse events associated with the therapy. Conclusion: The findings of this meta-analysis indicated that mesenchymal stem cells therapy may be effective in relieving pain and improving Oswestry Disability Index significantly in patients with lumbar discogenic pain. Mesenchymal stem cells therapy may also be associated with a lower risk of adverse events and reoperation rates.

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.

Bone marrow lesions in osteoarthritis: From basic science to clinical implications

Osteoarthritis (OA) is the most prevalent musculoskeletal disease characterized by multiple joint structure damages, including articular cartilage, subchondral bone and synovium, resulting in disability and economic burden. Bone marrow lesions (BMLs) are common and important magnetic resonance imaging (MRI) features in OA patients. Basic and clinical research on subchondral BMLs in the pathogenesis of OA has been a hotspot. New evidence shows that subchondral bone degeneration, including BML and angiogenesis, occurs not only at or after cartilage degeneration, but even earlier than cartilage degeneration. Although BMLs are recognized as important biomarkers for OA, their exact roles in the pathogenesis of OA are still unclear, and disputes about the clinical impact and treatment of BMLs remain. This review summarizes the current basic and clinical research progress of BMLs. We particularly focus on molecular pathways, cellular abnormalities and microenvironmental changes of subchondral bone that contributed to the formation of BMLs, and emphasize the crosstalk between subchondral bone and cartilage in OA development. Finally, potential therapeutic strategies targeting BMLs in OA are discussed, which provides novel strategies for OA treatment.

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.

Immunomodulatory Mechanism and Potential Application of Dental Pulp-Derived Stem Cells in Immune-Mediated Diseases

Dental pulp stem cells (DPSCs) are mesenchymal stem cells (MSCs) derived from dental pulp tissue, which have high self-renewal ability and multi-lineage differentiation potential. With the discovery of the immunoregulatory ability of stem cells, DPSCs have attracted much attention because they have similar or even better immunomodulatory effects than MSCs from other sources. DPSCs and their exosomes can exert an immunomodulatory ability by acting on target immune cells to regulate cytokines. DPSCs can also migrate to the lesion site to differentiate into target cells to repair the injured tissue, and play an important role in tissue regeneration. The aim of this review is to summarize the molecular mechanism and target cells of the immunomodulatory effects of DPSCs, and the latest advances in preclinical research in the treatment of various immune-mediated diseases, providing new reflections for their clinical application. DPSCs may be a promising source of stem cells for the treatment of immune-mediated diseases.

Progress and emerging techniques for biomaterial-based derivation of mesenchymal stem cells (MSCs) from pluripotent stem cells (PSCs)

The use of mesenchymal stem cells (MSCs) for clinical purposes has skyrocketed in the past decade. Their multilineage differentiation potentials and immunomodulatory properties have facilitated the discovery of therapies for various illnesses. MSCs can be isolated from infant and adult tissue sources, which means they are easily available. However, this raises concerns because of the heterogeneity among the various MSC sources, which limits their effective use. Variabilities arise from donor- and tissue-specific differences, such as age, sex, and tissue source. Moreover, adult-sourced MSCs have limited proliferation potentials, which hinders their long-term therapeutic efficacy. These limitations of adult MSCs have prompted researchers to develop a new method for generating MSCs. Pluripotent stem cells (PSCs), such as embryonic stem cells and induced PSCs (iPSCs), can differentiate into various types of cells. Herein, a thorough review of the characteristics, functions, and clinical importance of MSCs is presented. The existing sources of MSCs, including adult- and infant-based sources, are compared. The most recent techniques for deriving MSCs from iPSCs, with a focus on biomaterial-assisted methods in both two- and three-dimensional culture systems, are listed and elaborated. Finally, several opportunities to develop improved methods for efficiently producing MSCs with the aim of advancing their various clinical applications are described.

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.

Intra-Articular Injection of Autologous Micro-Fragmented Adipose Tissue for the Treatment of Knee Osteoarthritis: A Prospective Interventional Study

Background: To investigate the efficacy and safety of autologous micro-fragmented adipose tissue (MF-AT) for improving joint function and cartilage repair in patients with knee osteoarthritis. Methods: From March 2019 to December 2020, 20 subjects (40 knees) between 50 and 65 years old suffering from knee osteoarthritis were enrolled in the study and administered a single injection of autologous MF-A. The data of all patients were prospectively collected. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), knee society score (KSS), hospital for special surgery (HSS) score, visual analogue score (VAS) pain score, changes in cartilage Recht grade on magnetic resonance imaging (MRI) and adverse events were analyzed before and 3, 6, 9, 12 and 18 months after injection. Results: The WOMAC, VAS, KSS and HSS scores at 3, 6, 9, 12 and 18 months after injection were improved compared with those before injection (p < 0.05). There was no significant difference in WOMAC scores between 9 and 12 months after injection (p > 0.05), but the WOMAC score 18 months after injection was worse than that at the last follow-up (p < 0.05). The VAS, KSS and HSS scores 9, 12 and 18 months after injection were worse than those at the last follow-up (p < 0.05). The Recht score improvement rate was 25%. No adverse events occurred during the follow-up. Conclusions: Autologous MF-AT improves knee function and relieves pain with no adverse events. However, the improved knee function was not sustained, with the best results occurring 9–12 months after injection and the cartilage regeneration remaining to be investigated.

Intra-articular Injection of Autologous Adipose-Derived Stem Cells or Stromal Vascular Fractions: Are They Effective for Patients With Knee Osteoarthritis? A Systematic Review With Meta-analysis of Randomized Controlled Trials

BACKGROUND

Intra-articular injection of adipose-derived stem cells, which are divided into adipose-derived mesenchymal stem cells (ASCs) and adipose-derived stromal vascular fractions (ADSVFs), has been reported to be a viable treatment modality for knee osteoarthritis (OA); however, its efficacy remains limited.

PURPOSE

This study aimed to provide comprehensive information about the efficacy and safety of intra-articular injections of autologous ASCs and ADSVFs without adjuvant treatment in patients with knee OA.

STUDY DESIGN

Meta-analysis; Level of evidence, 1.

METHODS

A systematic search of the MEDLINE, Embase, Web of Science, and Cochrane Library databases was performed to identify randomized controlled trials (RCTs) that evaluated the efficacy and safety of intra-articular injections of autologous ASCs or ADSVFs without adjuvant treatments compared with placebo or hyaluronic acid in patients with knee OA. Clinically, the 100-mm visual analog scale for pain relief and the Western Ontario and McMaster Universities Osteoarthritis Index for functional improvement were implemented. Radiologically, cartilage status was assessed using magnetic resonance imaging (MRI). Procedure-related knee pain, swelling, and adverse events (AEs) were evaluated for safety. Additionally, we performed subgroup analyses comparing ASCs versus ADSVFs. Methodological quality was assessed using the modified Coleman Methodology Score (mCMS).

RESULTS

A total of 5 RCTs were included in this study. Based on the meta-analysis, ASCs or ADSVFs showed significantly better pain relief at 6 months (Z = 7.62; P < .0001) and 12 months (Z = 7.21; P < .0001) and functional improvement at 6 months (Z = 4.13; P < .0001) and 12 months (Z = 3.79; P = .0002), without a difference in procedure-related knee pain or swelling compared with controls. Although a meta-analysis with regard to cartilage improvements was not performed owing to heterogeneous MRI assessment, 3 studies reported significantly improved cartilage status after the injection. No serious AEs associated with ASCs or ADSVFs were reported. Subgroup analyses showed similar efficacy between ASC and ADSVF treatments. The median mCMS was 70 (range, 55-75).

CONCLUSION

For patients with knee OA, intra-articular injection of autologous ASCs or ADSVFs without adjuvant treatment showed remarkable clinical efficacy and safety at short-term follow-up. Some degree of efficacy has been shown for cartilage regeneration in knee OA, although the evidence remains limited. Further RCTs that directly compare ASCs and ADSVFs are needed.

Intra-articular injection of culture-expanded adipose tissue-derived stem cells for knee osteoarthritis: Assessments with clinical symptoms and quantitative measurements of articular cartilage volume

BACKGROUND

Intra-articular administration of adipose tissue-derived stem cells (ADSC) is an alternative treatment option for knee osteoarthritis (OA) after conventional treatment fails; however, the clinical results related to the severity of OA grade and changes of cartilage volumes after the administration of ADSC is unknown. This study aimed to determine 1) clinical outcomes after the ADSC administration in knee OA with consideration of radiographic OA grades and 2) changes in cartilage volumes after ADSC administration.

METHODS

This observational study included 86 knees from 51 patients who underwent intra-articular administration of cultured ADSC; 47 patients (80 knees) completed follow-up for 6 months (follow-up rate: 93%). The Knee injury and Osteoarthritis Outcome Scores (KOOS) were reported at baseline and 1, 3, and 6 months after the administration. The efficacy rate in the Outcome Measures in Arthritis Clinical Trials-Osteoarthritis Research Society International (OMERACT-OARSI) was evaluated using the KOOS. Cartilage volume of the knee joint was measured using quantitative 3-dimensional magnetic resonance imaging (3D-MRI) software at baseline and 6 months in 52 knees in 31 patients (follow-up rate: 61%).

RESULTS

All items on the KOOS except "sports/recreation" improved significantly at 6 months with more significance in knees with a Kellgren-Lawrence (KL) grade 2 or 3 compared with KL grade 4 knees. The OMERACT-OARSI responder at 6 months was significantly greater in knees with KL grade 2 or 3 (64%) than in knees with KL grade 4 (42%, p = 0.045). Cartilage volume changes varied among patients and were not related to the changes in KOOS after ADSC administration.

CONCLUSIONS

Intra-articular administration of ADSC in knee OA improved KOOS at 6 months. The effects were more significant in knees with KL grade 2 or 3 than with KL grade 4. Changes in KOOS were not related to change in cartilage volumes after ADSC administration.

Inhibition of SMAD3 effectively reduces ADAMTS-5 expression in the early stages of osteoarthritis

OBJECTIVE

As one of the most important protein-degrading enzymes, ADAMTS-5 plays an important role in the regulation of cartilage homeostasis, while miRNA-140 is specifically expressed in cartilage, which can inhibit the expression of ADAMTS-5 and delay the progression of OA (osteoarthritis). SMAD3 is a key protein in the TGF-β signaling pathway, inhibiting the expression of miRNA-140 at the transcriptional and post-transcriptional levels, and studies have confirmed the high expression of SMAD3 in knee cartilage degeneration, but whether SMAD3 can mediate the expression of miRNA-140 to regulate ADAMTS-5 remains unknown.

METHODS

Sprague-Dawley (SD) rat chondrocytes were extracted in vitro and treated with a SMAD3 inhibitor (SIS3) and miRNA-140 mimics after IL-1 induction. The expression of ADAMTS-5 was detected at the protein and gene levels at 24 h, 48 h, and 72 h after treatment. The OA model of SD rats was created using the traditional Hulth method in vivo, with SIS3 and lentivirus packaged miRNA-140 mimics injected intra-articularly at 2 weeks, 6 weeks and 12 weeks after surgery. The expression of miRNA-140 and ADAMTS-5 in the knee cartilage tissue was observed at the protein and gene levels. Concurrently, knee joint specimens were fixed, decalcified, and embedded in paraffin prior to immunohistochemical, Safranin O/Fast Green staining, and HE staining analyses for ADAMTS-5 and SMAD3.

RESULTS

In vitro, the expression of ADAMTS-5 protein and mRNA in the SIS3 group decreased to different degrees at each time point. Meanwhile, the expression of miRNA-140 in the SIS3 group was significantly increased, and the expression of ADAMTS-5 in the miRNA-140 mimics group was also significantly downregulated (P < 0.05). In vivo, it was found that ADAMTS-5 protein and gene were downregulated to varying degrees in the SIS3 and miRNA-140 mimic groups at three time points, with the most significant decrease at the early stage (2 weeks) (P < 0.05), and the expression of miRNA-140 in the SIS3 group was significantly upregulated, similar to the changes detected in vitro. Immunohistochemical results showed that the expression of ADAMTS-5 protein in the SIS3 and miRNA-140 groups was significantly downregulated compared to that in the blank group. The results of hematoxylin and eosin staining showed that in the early stage, there was no obvious change in cartilage structure in the SIS3 and miRNA-140 mock groups. The same was observed in the results of Safranin O/Fast Green staining; the number of chondrocytes was not significantly reduced, and the tide line was complete.

CONCLUSION

The results of in vitro and in vivo experiments preliminarily showed that the inhibition of SMAD3 significantly reduced the expression of ADAMTS-5 in early OA cartilage, and this regulation might be accomplished indirectly through miRNA-140.

Advances in Mesenchymal Stem Cell Therapy for Osteoarthritis: From Preclinical and Clinical Perspectives

The prevalence of osteoarthritis (OA), a degenerative disorder of joints, has substantially increased in recent years. Its key pathogenic hallmarks include articular cartilage destruction, synovium inflammation, and bone remodeling. However, treatment outcomes are unsatisfactory. Until recently, common therapy methods, such as analgesic and anti-inflammatory treatments, were aimed to treat symptoms that cannot be radically cured. Mesenchymal stem cells (MSCs), i.e., mesoderm non-hematopoietic cells separated from bone marrow, adipose tissue, umbilical cord blood, etc., have been intensively explored as an emerging technique for the treatment of OA over the last few decades. According to existing research, MSCs may limit cartilage degradation in OA by interfering with cellular immunity and secreting a number of active chemicals. This study aimed to examine the potential mechanism of MSCs in the treatment of OA and conduct a thorough review of both preclinical and clinical data.

An observational study evaluating the efficacy of microfragmented adipose tissue in the treatment of osteoarthritis

Aim: Osteoarthritis (OA) prevalence is increased in ageing and obese populations. This prospective single-arm cohort study aimed to investigate the efficacy of autologous microfragmented adipose tissue treatment of severe knee or shoulder OA. Materials & methods: Participants received an intra-articular microfragmented adipose tissue injection to the affected joint(s). Multiple patient reported outcome measures (PROMS) were recorded from 0 to 52 weeks for 63 consecutive joints. Results: Compared with baseline, there were significant improvements in all PROMS from 2 to 12 weeks and maintained at 52 weeks. Regression analysis revealed an inverse correlation with BMI and change in PROMS for knee joints. Conclusion: Our observed findings suggest this approach represents a safe, effective treatment for moderate-to-severe knee and shoulder OA, although efficacy may be reduced with increasing obesity.

Outcome of Intra-articular Injection of Total Stromal Cells and Platelet-Rich Plasma in Primary Knee Osteoarthritis: A Randomized Clinical Trial

INTRODUCTION

 Mesenchymal stem cell (MSC) therapy appeared promising in knee osteoarthritis (OA). We examined if a single intra-articular (IA) autologous total stromal cells (TSC) and platelet-rich plasma (PRP) injection improved knee pain, physical function, and articular cartilage thickness in knee OA.

METHODS

 The study was performed in the physical medicine and rehabilitation department of Bangabandhu Shaikh Mujib Medical University, Dhaka, Bangladesh. Knee OA was diagnosed according to the American College of Rheumatology criteria and randomly assigned to treatment (received TSC and PRP) and control groups. Kallgreen-Lawrance (KL) scoring system was used to grade primary knee OA. The Visual Analogue Scale (VAS, 0-10 cm) for pain, WOMAC (Western Ontario and McMaster Universities Arthritis Index) for physical function, and medial femoral condylar cartilage (MFC) thickness (millimeters) under ultrasonogram (US) were documented and compared between groups before and after treatment. Statistical Package analyzed data for Social Scientists (SPSS 22.0; IBM Corp, Armonk, NY) was used for data analysis. Pre- and post-intervention outcomes were measured using the Wilcoxon-sign test, whereas Mann-Whitney U-test calculated the difference between groups; a p-value <0.05 was considered statistically significant.  Result: In the treatment group, 15 received IA-TSC and PRP preparation, and in the control group, 15 patients received no injection, but quadricep muscle-strengthening exercise. There was no significant difference between groups regarding VAS for pain, WOMAC physical function, and cartilage thickness before starting the treatment and two weeks after intervention. VAS for pain and WOMAC physical function scores improved profoundly in the treatment group after 12 and 24 weeks of intervention; the pain and physical function scores difference between groups was also significant. However, significant mean femoral cartilage thickness was not changed until the end of 24 weeks (U=175.00, p=0.009 two-tailed and U= 130.00, p=0.016 two-tailed, respectively, for right and left knee).

CONCLUSION

 Single TSC and PRP injection reduces knee pain and improves physical function and cartilage thickness in knee OA. While pain and physical function improvement happen earlier, cartilage thickness change takes more time.

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.

Synovial Fluid Derived from Human Knee Osteoarthritis Increases the Viability of Human Adipose-Derived Stem Cells through Upregulation of FOSL1

Knee osteoarthritis (Knee OA) is an irreversible condition that causes bone deformity and degeneration of the articular cartilage that comprises the joints, resulting in chronic pain and movement disorders. The administration of cultured adipose-derived stem cells (ADSCs) into the knee joint cavity improves the clinical symptoms of Knee OA; however, the effect of synovial fluid (SF) filling the joint cavity on the injected ADSCs remains unclear. In this study, we investigated the effect of adding SF from Knee OA patients to cultured ADSCs prepared for therapeutic use in an environment that mimics the joint cavity. An increase in the viability of ADSCs was observed following the addition of SF. Gene expression profiling of SF-treated ADSCs using DNA microarrays revealed changes in several genes involved in cell survival. Of these genes, we focused on FOSL1, which is involved in the therapeutic effect of ADSCs and the survival and proliferation of cancer stem cells. We confirmed the upregulation of FOSL1 mRNA and protein expression using RT-PCR and western blot analysis, respectively. Next, we knocked down FOSL1 in ADSCs using siRNA and observed a decrease in cell viability, indicating the involvement of FOSL1 in the survival of ADSCs. Interestingly, in the knockdown cells, ADSC viability was also decreased by SF exposure. These results suggest that SF enhances cell viability by upregulating FOSL1 expression in ADSCs. For therapy using cultured ADSCs, the therapeutic effect of ADSCs may be further enhanced if an environment more conducive to the upregulation of FOSL1 expression in ADSCs can be established.

Novel potential therapeutic targets of alopecia areata

Alopecia areata (AA) is a non-scarring hair loss disorder caused by autoimmunity. The immune collapse of the hair follicle, where interferon-gamma (IFN-γ) and CD8+ T cells accumulate, is a key factor in AA. However, the exact functional mechanism remains unclear. Therefore, AA treatment has poor efficacy maintenance and high relapse rate after drug withdrawal. Recent studies show that immune-related cells and molecules affect AA. These cells communicate through autocrine and paracrine signals. Various cytokines, chemokines and growth factors mediate this crosstalk. In addition, adipose-derived stem cells (ADSCs), gut microbiota, hair follicle melanocytes, non-coding RNAs and specific regulatory factors have crucial roles in intercellular communication without a clear cause, suggesting potential new targets for AA therapy. This review discusses the latest research on the possible pathogenesis and therapeutic targets of AA.

Large-scale expansion of human umbilical cord-derived mesenchymal stem cells using PLGA@PLL scaffold

Mesenchymal stem cells (MSCs) are highly important in biomedicine and hold great potential in clinical treatment for various diseases. In recent years, the capabilities of MSCs have been under extensive investigation for practical application. Regarding therapy, the efficacy usually depends on the amount of MSCs. Nevertheless, the yield of MSCs is still limited due to the traditional cultural methods. Herein, we proposed a three-dimensional (3D) scaffold prepared using poly lactic-co-glycolic acid (PLGA) nanofiber with polylysine (PLL) grafting, to promote the growth and proliferation of MSCs derived from the human umbilical cord (hUC-MSCs). We found that the inoculated hUC-MSCs adhered efficiently to the PLGA scaffold with good affinity, fast growth rate, and good multipotency. The harvested cells were ideally distributed on the scaffold and we were able to gain a larger yield than the traditional culturing methods under the same condition. Thus, our cell seeding with a 3D scaffold could serve as a promising strategy for cell proliferation in the large-scale production of MSCs. Moreover, the simplicity and low preparation cost allow this 3D scaffold to extend its potential application beyond cell culture.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40643-023-00635-6.