Meta-Analysis of Adipose Tissue Derived Cell-Based Therapy for the Treatment of Knee Osteoarthritis

Understanding and controlling the variables for stromal vascular fraction therapy

In regenerative medicine, the isolation of mesenchymal stromal cells (MSCs) from the adipose tissue's stromal vascular fraction (SVF) is a critical area of study. Our review meticulously examines the isolation process of MSCs, starting with the extraction of adipose tissue. The choice of liposuction technique, anatomical site, and immediate processing are essential to maintain cell functionality. We delve into the intricacies of enzymatic digestion, emphasizing the fine-tuning of enzyme concentrations to maximize cell yield while preventing harm. The review then outlines the filtration and centrifugation techniques necessary for isolating a purified SVF, alongside cell viability assessments like flow cytometry, which are vital for confirming the efficacy of the isolated MSCs. We discuss the advantages and drawbacks of using autologous vs allogeneic SVF sources, touching upon immunocompatibility and logistical considerations, as well as the variability inherent in donor-derived cells. Anesthesia choices, the selection between hypodermic needles vs liposuction cannulas, and the role of adipose tissue lysers in achieving cellular dissociation are evaluated for their impact on SVF isolation. Centrifugation protocols are also analyzed for their part in ensuring the integrity of the SVF. The necessity for standardized MSC isolation protocols is highlighted, promoting reproducibility and successful clinical application. We encourage ongoing research to deepen the understanding of MSC biology and therapeutic action, aiming to further the field of regenerative medicine. The review concludes with a call for rigorous research, interdisciplinary collaboration, and strict adherence to ethical and regulatory standards to safeguard patient safety and optimize treatment outcomes with MSCs.

Ultrasound and patient-reported outcomes of rotator cuff repair with new acellular human allograft at 6 months and 1 year post surgery

Background

Determine the effect of a novel acellular cannulated dermal allograft on tendon-to-bone healing, retear rates, and clinical outcomes over a 12-month period.

Methods

This was a single surgeon prospective nonrandomized case series. Patients with medium sized full-thickness superior and posterosuperior rotator cuff tears, as confirmed by magnetic resonance imaging, were consented. Patients were excluded if they had fatty atrophy indicative of Goutallier grade III or IV. The allograft is a cannulated rectangular prism that has a 5-year shelf life, does not require prehydration, and does not need to be trimmed to size. Outcome metrics included ultrasound assessment at 1-year as well as 6-month patient-reported outcomes (PROs) scores.

Results

31 patients consented and enrolled in this consecutive cohort series. 9 patients were excluded, and statistical analysis was performed on the remaining 22 patients. There were 9 females and 13 males. The average age was 59.27 ± 7.48 year old. The average supraspinatus short axis measurement in males was 0.56 ± 0.12 cm and 0.52 ± 0.09 cm in females (P = .44). The average supraspinatus long axis measurement in males was 0.61 ± 0.18 cm and 0.55 ± 0.14 cm in females (P = .46). The average infraspinatus short axis measurement in males was 0.48 ± 0.10 cm and 0.50 ± 0.13 in females (P = .74). The average infraspinatus long axis measurement in males was 0.44 ± 0.12 cm and 0.43 ± 0.08 cm in females (P = .84). Of the 19 patients who completed baseline and 6-month PRO's, 17 achieved the minimal clinical important difference for American Shoulder and Elbow Surgeons and Patient-Reported Outcomes Measurement Information SystemUE 7a. Retear occurred in 2 cases. The remaining 20 cases have all demonstrated healing or fully healed repairs at their most recent clinical visits with no additional cases of retears.

Conclusion

This study is the first to report the results of a novel acellular dermal allograft for rotator cuff repair augmentation. Satisfactory PRO measures and robust tendon healing at 1 year, as measured by ultrasound, demonstrate the utility of a cannulated human acellular dermal allograft as a viable biologic augmentation device for rotator cuff repair.

Arthroscopy With Adipose-Derived Stromal Vascular Fraction Using a Selective Tissue Engineering Photo-Stimulation Technique for the Treatment of Mild to Moderate Knee Osteoarthritis

Osteoarthritis (OA) is characterized by articular cartilage degeneration, synovial inflammation, and subchondral bone thickening, affecting the synovial joint as an organ and leading to pain and disability. Subcutaneous stromal vascular fraction is safe and relieves pain, improves function, and repairs cartilage defects in patients with knee OA. Our goal is to describe step-by-step the arthroscopic treatment of mild to moderate knee OA with photo-stimulated stromal vascular fraction harvested from the thigh using a selective tissue engineering photo-stimulation ("One S.T.E.P.") technique.

Seven-Year Longitudinal Study: Clinical Evaluation of Knee Osteoarthritic Patients Treated with Mesenchymal Stem Cells

Background/Objectives: Numerous studies have demonstrated the safety and efficacy of intraarticular stem cell injections for treating osteoarthritic knee joints, reporting symptom reduction and pain relief within a few months of treatment. Here, we report the results of a 7-year follow-up after a single intraarticular injection of 0.5-1 × 107 autologous adipose tissue-derived mesenchymal stem cells in patients with OA (Kellgren-Lawrence grade 2 to 4). Methods: Nine patients were treated, and two patients had bilateral disease. Patients were evaluated clinically and radiologically using X-ray and MRI. A comprehensive statistical analysis was undertaken to evaluate the obtained results. Results: All clinical scores and range of motion significantly improved within the first six months after injection. At the 18-month time point, a significant improvement in cartilage structure was observed on MRI while X-ray showed no changes in subchondral bone of distal femur and proximal tibia. At the 60-month time point, the clinical scores were still improved compared to baseline, except for the range of motion, which decreased almost back to the baseline level. At 84 months, the clinical scores decreased significantly toward the baseline level, but the MRI structural characteristics of cartilage still remained significantly better than those measured at baseline. Conclusions: Adipose tissue-derived stem cell therapy has substantial long-term clinical effects on patients with knee osteoarthritis.

Intra-Articular Application of Autologous, Fat-Derived Orthobiologics in the Treatment of Knee Osteoarthritis: A Systematic Review

The aim of this study was to review the current literature regarding the effects of intra-articularly applied, fat-derived orthobiologics (FDO) in the treatment of primary knee osteoarthritis over a mid-term follow-up period. A systematic literature search was conducted on the online databases of Scopus, PubMed, Ovid MEDLINE, and Cochrane Library. Studies investigating intra-articularly applied FDO with a minimum number of 10 knee osteoarthritis patients, a follow-up period of at least 2 years, and at least 1 reported functional parameter (pain level or Patient-Reported Outcome Measures) were included. Exclusion criteria encompassed focal chondral defects and techniques including additional arthroscopic bone marrow stimulation. In 28 of 29 studies, FDO showed a subjective improvement in symptoms (pain and Patient-Reported Outcome Measures) up to a maximum follow-up of 7.2 years. Radiographic cartilage regeneration up to 3 years postoperatively, as well as macroscopic cartilage regeneration investigated via second-look arthroscopy, may corroborate the favorable clinical findings in patients with knee osteoarthritis. The methodological heterogeneity in FDO treatments leads to variations in cell composition and represents a limitation in the current state of knowledge. However, this systematic review suggests that FDO injection leads to beneficial mid-term results including symptom reduction and preservation of the affected joint in knee osteoarthritis patients.

Recent Trends in Adipose Tissue-Derived Injectable Therapies for Osteoarthritis: A Scoping Review of Animal Models

Background and Objectives: This scoping review investigates recent trends in adipose tissue-derived injectable therapies for osteoarthritis (OA) in animal models, focusing on minimally manipulated or lightly processed adipose tissue. By evaluating and examining the specific context in which these therapies were investigated across diverse animal OA models, this review aims to provide valuable insights that will inform and guide future research and clinical applications in the ongoing pursuit of effective treatments for osteoarthritis. Materials and Methods: This research conducted a comprehensive literature review of PubMed and Embase to determine studies about minimally manipulated adipose tissue-derived injectable therapies for osteoarthritis investigated using animal models. The primary search found 530 results. After excluding articles that focused on spontaneous osteoarthritis; on transfected, preconditioned, cultured, or co-cultured adipose-derived stem cells; and articles with unavailable full text, we included 11 articles in our review. Results: The examined therapies encompassed mechanical micro-fragmented adipose tissue (MFAT) and stromal vascular fraction (SVF) obtained via collagenase digestion and centrifugation. These interventions were evaluated across various animal models, including mice, rats, rabbits, and sheep with induced OA. Notably, more studies concentrated on surgically induced OA rather than chemically induced OA. The assessment of these therapies focused on elucidating their protective immunomodulatory, anti-inflammatory, and chondroregenerative potential through comprehensive evaluations, including macroscopic assessments, histological analyses, immunohistochemical examinations, and biochemical assays. Conclusions: This review provides a comprehensive analysis of adipose tissue-derived injectable therapies for osteoarthritis across diverse animal models. While revealing potential benefits and insights, the heterogeneity of data and the limited number of studies highlight the need for further research to formulate conclusive recommendations for clinical applications.

Pain Management Strategies in Osteoarthritis

Pain is the major symptom of osteoarthritis (OA) and is an important factor in strategies to manage this disease. However, the current standard of care does not provide satisfactory pain relief for many patients. The pathophysiology of OA is complex, and its presentation as a clinical syndrome is associated with the pathologies of multiple joint tissues. Treatment options are generally classified as pharmacologic, nonpharmacologic, surgical, and complementary and/or alternative, typically used in combination to achieve optimal results. The goals of treatment are the alleviation of symptoms and improvement in functional status. Several studies are exploring various directions for OA pain management, including tissue regeneration techniques, personalized medicine, and targeted drug therapies. The aim of the present narrative review is to extensively describe all the treatments available in the current practice, further describing the most important innovative therapies. Advancements in understanding the molecular and genetic aspects of osteoarthritis may lead to more effective and tailored treatment approaches in the future.

Comparison studies identify mesenchymal stromal cells with potent regenerative activity in osteoarthritis treatment

Osteoarthritis affects 15% of people over 65 years of age. It is characterized by articular cartilage degradation and inflammation, leading to joint pain and disability. Osteoarthritis is incurable and the patients may eventually need joint replacement. An emerging treatment is mesenchymal stromal cells (MSCs), with over two hundred clinical trials being registered. However, the outcomes of these trials have fallen short of the expectation, due to heterogeneity of MSCs and uncertain mechanisms of action. It is generally believed that MSCs exert their function mainly by secreting immunomodulatory and trophic factors. Here we used knee osteoarthritis mouse model to assess the therapeutic effects of MSCs isolated from the white adipose or dermal adipose tissue of Prrx1-Cre; R26tdTomato mice and Dermo1-Cre; R26tdTomato mice. We found that the Prrx1-lineage MSCs from the white adipose tissues showed the greatest in vitro differentiation potentials among the four MSC groups and single cell profiling showed that the Prrx1-lineage MSCs contained more stem cells than the Dermo1 counterpart. Only the Prrx1-lineage cells isolated from white adipose tissues showed long-term therapeutic effectiveness on early-stage osteoarthritis models. Mechanistically, Prrx1-lineage MSCs differentiated into Col2+ chondrocytes and replaced the damage cartilage, activated Col1 expressing in resident chondrocytes, and inhibited synovial inflammation. Transcriptome analysis showed that the articular chondrocytes derived from injected MSCs expressed immunomodulatory cytokines, trophic factors, and chondrocyte-specific genes. Our study identified a MSC population genetically marked by Prrx1 that has great multipotentiality and can differentiate into chondrocytes to replace the damaged cartilage.

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.

Autologous micro-fragmented adipose tissue injection provides significant and prolonged clinical improvement in patients with knee osteoarthritis: a case-series study

PURPOSE

Among the conservative strategies to manage patients with symptomatic knee osteoarthritis (OA), an innovative approach exploiting the regenerative capability of adipose tissue and its resident MSCs (Mesenchymal Stem Cells or Medicinal Signalling Cells) has been proposed with encouraging results. This study aims to demonstrate the benefits of autologous micro-fragmented adipose tissue (MAT) injection in the conservative treatment of knee osteoarthritis and whether any variables may affect the outcome. This is a case series single-centre study in which patients underwent intraarticular MAT injection without any associated procedures.

METHODS

Based on inclusion and exclusion criteria, 49 patients (67 Knees) were included and retrospectively analysed with a mean follow-up of 34.04 ± 13.62 months (minimum 11 - maximum 59). Patients were assessed through the WOMAC and KOOS questionnaires at baseline (pre-treatment) and 1-, 3-, 6-, 12-, 24- and 36-month follow-up. A minimal clinically important difference (MCID) of at least 7.5 points for the WOMAC pain scale and 7.2 for the WOMAC function scale compared to the baseline value was used.

RESULTS

WOMAC and KOOS scores improved after treatment compared to baseline at all follow-ups with p < 0.001. Male gender and Kellgren-Lawrence (KL) grade 2 were associated with smaller improvement in WOMAC and KOOS scores (with respect to females and to KL grade 1, respectively) up to 24 months. The percentage of patients who reach the MCID for WOMAC pain is generally lower than that of patients who reach the MCID for WOMAC function (around 80% at all time points), but it increases significantly over time. Moreover, the baseline score of the WOMAC pain and function influence the outcome. Patients with worse symptoms are more likely to reach the MCID.

CONCLUSIONS

Intra-articular knee injection of MAT for the treatment of knee osteoarthritis (KOA), recalcitrant to traditional conservative treatments, proved to be effective in a high percentage of cases. The positive association between a worse pre-operative score and a better clinical response to the treatment would support the idea that intra-articular administration of MAT could be considered in patients with very symptomatic KOA in which joint-replacement surgeries are not indicated (or accepted).

LEVEL OF EVIDENCE

IV, case series.

Heterogeneous Cells as well as Adipose-Derived Stromal Cells in Stromal Vascular Fraction Contribute to Enhance Anabolic and Inhibit Catabolic Factors in Osteoarthritis

The stromal-vascular fraction (SVF), comprising heterogeneous cell populations and adipose-derived stromal cells (ADSCs), has therapeutic potential against osteoarthritis (OA); however, the underlying mechanism remains elusive. This study aimed to investigate the therapeutic effects of heterogeneous cells in rabbit SVF on rabbit chondrocytes. Rabbit SVF and ADSCs were autografted into knees at OA onset. The SVF (1 × 105) and low-dose ADSCs (lADSC; 1 × 104) groups adjusted for their stromal cell content were compared. Animals were euthanized 8 and 12 weeks after OA onset for macroscopic and histological analyses of OA progression and synovitis. Immunohistochemical and real-time polymerase chain reaction assessments were conducted. In vitro, immune-fluorescent double staining was performed for SVF to stain macrophages with F4/80, CD86(M1), and CD163(M2). OA progression was markedly suppressed, and synovitis was reduced in the SVF groups (OARSI histological score 8 W: 6.8 ± 0.75 vs. 3.8 ± 0.75, p = 0.001; 12 W: 8.8 ± 0.4 vs. 5.4 ± 0.49, p = 0.0002). The SVF groups had higher expression of collagen II and SOX9 in cartilage and TGF-β and IL-10 in the synovium, lower expression of MMP-13, and lower macrophage M1/M2 ratio than the lADSC groups. Immunofluorescent double staining revealed a markedly higher number of M2 than that of M1 macrophages in the SVF. The therapeutic effects of SVF on chondrocytes were superior than those of lADSCs, with enhanced anabolic and inhibited catabolic factors. Heterogeneous cells, mainly M2 macrophages in the SVF, enhanced growth factor secretion and chondrocyte-protective cytokines, thus benefiting chondrocytes and knee joint homeostasis. Overall, the SVF is a safe, relatively simple, and a useful treatment option for OA.

Methods of Conservative Intra-Articular Treatment for Osteoarthritis of the Hip and Knee

BACKGROUND

Osteoarthritis is a degenerative joint disease that is becoming increasingly common as the population ages. Conservative treatment for hip or knee osteoarthritis has been limited to pain control. Intra-articular injections for targeted local treatment have been widely used in clinical practice for many years.

METHODS

This review is based on publications retrieved by a selective literature search, including recent meta-analyses, systematic reviews, randomized controlled trials (RCTs), and current guidelines.

RESULTS

In Germany, the 12-month prevalence of osteoarthritis in adults is 17.9%. Conservative treatments are intended to alleviate symptoms and do not affect the progression of the disease. Glucocorticoids can be used to relieve otherwise intractable pain in the short term, but their prolonged use increases the risk of cartilage loss and progression of osteoarthritis. According to multiple guidelines, there is only weak evidence for the use of hyaluronic acid. Evidence does exist that high-molecular-weight hyaluronic acid may lead to better outcomes than the low-molecular-weight form. RCTs have revealed no more than short-term clinical efficacy for a variety of specific therapeutic approaches, including the use of cytokine inhibitors. Other treatments, e.g., with platelet-enriched plasma, aspirates from bone marrow or adipose tissue, or expanded mesenchymal stromal cells (MSC), have not been found to have clinically relevant long-term effects.

CONCLUSION

In view of the scant available evidence, further standardized RCTs will be needed to give a more comprehensive picture of the efficacy of intra-articular treatments for hip and knee osteoarthritis.

Efficacy and Long-Term Outcomes of Intra-Articular Autologous Micro-Fragmented Adipose Tissue in Individuals with Glenohumeral Osteoarthritis: A 36-Month Follow-Up Study

BACKGROUND

Glenohumeral osteoarthritis (GOA) is associated with disabling shoulder pain that affects everyday life. Its management comprises various treatment approaches, both conservative and surgical. Regenerative medicine has gained a major role in the conservative treatment of osteoarthritis. Intra-articular injection of adipose-derived mesenchymal stem cells (ADMSCs) is a widely used regenerative medicine approach. The aim of this retrospective study was to report the safety and clinical outcomes of intra-articular injection of ADMSCs in patients with GOA over 36-months.

METHODS

This retrospective observational study involved patients with chronic shoulder pain resistant to standard conservative treatment and a diagnosis of concentric GOA, who received an intra-articular injection of autologous micro-fragmented adipose tissue (μFAT). The values of the Constant-Murley score (CMS), the visual analog scale (VAS), and the simple shoulder test (SST), collected at baseline and at 12, 24, and 36 months, were analyzed to assess treatment efficacy. The single assessment numeric evaluation (SANE) was used to rate patient satisfaction. The Friedman test was used to compare observations of CMS, VAS, and SST values repeated on the same subjects. The significance threshold was set at 0.05.

RESULTS

The participants were 65 patients with a mean age of 54.19 years and a nearly equal gender distribution. Most had mild concentric GOA classified as Samilson-Prieto grade 1. The mean follow-up duration was 44.25 months. The postoperative clinical scores showed significant improvement. At 36 months, the CMS was 84.60, the VAS score was 3.34, and the SST score was 10.15 (all p < 0.0001). The SANE score at 36 months indicated that 54 patients (83.08%) were completely satisfied with the treatment.

CONCLUSION

ADMSC treatment exerted favorable effects on the clinical outcomes of patients with GOA, providing pain relief and improving shoulder function. Our data support its use as a conservative treatment option for osteoarthritis.

Two Amnion-Derived Mesenchymal Stem-Cells Injections to Osteoarthritic Elbows in Dogs-Pilot Study

The aim of the study was to investigate the potential of cell-based regenerative therapy for elbow joints affected by osteoarthritis. Interest was focused on two intra-articular applications of amnion-derived mesenchymal stem cells (A-MSCs) to a group of different breeds of dogs with elbow osteoarthritis (13 joints). Two injections were performed 14 days apart. We evaluated synovial fluid biomarkers, such as IFN-γ, IL-6, IL-15, IL-10, MCP-1, TNF-α, and GM-CSF, by multiplex fluorescent micro-bead immunoassay in the treated group of elbows (n = 13) (day 0, day 14, and day 28) and in the control group of elbows (n = 9). Kinematic gait analysis determined the joint range of motion (ROM) before and after each A-MSCs application. Kinematic gait analysis was performed on day 0, day 14, and day 28. Kinematic gait analysis pointed out improvement in the average range of motion of elbow joints from day 0 (38.45 ± 5.74°), day 14 (41.7 ± 6.04°), and day 28 (44.78 ± 4.69°) with statistical significance (p < 0.05) in nine elbows. Correlation analyses proved statistical significance (p < 0.05) in associations between ROM (day 0, day 14, and day 28) and IFN-γ, IL-6, IL-15, MCP-1, TNF-α, and GM-CSF concentrations (day 0, day 14, and day 28). IFN-γ, IL-6, IL-15, MCP-1, GM-CSF, and TNF- α showed negative correlation with ROM at day 0, day 14, and day 28, while IL-10 demonstrated positive correlation with ROM. As a consequence of A-MSC application to the elbow joint, we detected a statistically significant (p < 0.05) decrease in concentration levels between day 0 and day 28 for IFN-γ, IL-6, and TNF-α and statistically significant increase for IL-10. Statistical significance (p < 0.05) was detected in TNF-α, IFN-γ, and GM-CSF concentrations between day 14 and the control group as well as at day 28 and the control group. IL-6 concentrations showed statistical significance (p < 0.05) between day 14 and the control group.

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).

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.

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.

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.

Cell-based therapies have disease-modifying effects on osteoarthritis in animal models. A systematic review by the ESSKA Orthobiologic Initiative. Part 1: adipose tissue-derived cell-based injectable therapies

PURPOSE

The aim of this systematic review was to determine if adipose tissue-derived cell-based injectable therapies can induce disease-modifying effects in joints affected by osteoarthritis (OA).

METHODS

A systematic review was performed on three electronic databases (PubMed, Web of Science, Embase) according to PRISMA guidelines. A synthesis of the results was performed investigating disease-modifying effects in preclinical studies comparing injectable adipose-derived products with OA controls or other products, different formulations or injection intervals, and the combination with other products. The risk of bias was assessed according to the SYRCLE's tool.

RESULTS

Seventy-one studies were included (2,086 animals) with an increasing publication trend over time. Expanded cells were used in 65 studies, 3 studies applied point of care products, and 3 studies investigated both approaches. Overall, 48 out of 51 studies (94%) reported better results with adipose-derived products compared to OA controls, with positive findings in 17 out of 20 studies (85%) in macroscopic, in 37 out of 40 studies (93%) in histological, and in 22 out of 23 studies (96%)  in immunohistochemical evaluations. Clinical and biomarker evaluations showed positive results in 14 studies out of 18 (78%) and 12 studies out of 14 (86%), while only 9 studies out of 17 (53%) of the imaging evaluations were able to detect differences versus controls. The risk of bias was low in 38% of items, unclear in 51%, and high in (11%).

CONCLUSION

The current preclinical models document consistent evidence of disease-modifying effects of adipose-derived cell-based therapies for the treatment of OA. The high heterogeneity of the published studies highlights the need for further targeted research to provide recommendations on the optimal methodologies for a more effective application of these injective therapies for the treatment of OA in clinical practice.

LEVEL OF EVIDENCE

II.

Autologous Adipose-Derived Tissue Stromal Vascular Fraction (AD-tSVF) for Knee Osteoarthritis

Adipose tissue contains adult mesenchymal stem cells that may modulate the metabolism when applied to other tissues. Stromal vascular fraction (SVF) can be isolated from adipose tissue mechanically and/or enzymatically. SVF was recently used to decrease the pain and improve the function of knee osteoarthritis (OA) patients. Primary and/or secondary OA causes inflammation and degeneration in joints, and regenerative approaches that may modify the natural course of the disease are limited. SVF may modulate inflammation and initiate regeneration in joint tissues by initiating a paracrine effect. Chemokines released from SVF may slow down degeneration and stimulate regeneration in joints. In this review, we overviewed articular joint cartilage structures and functions, OA, and macro-, micro-, and nano-fat isolation techniques. Mechanic and enzymatic SVF processing techniques were summarized. Clinical outcomes of adipose tissue derived tissue SVF (AD-tSVF) were evaluated. Medical devices that can mechanically isolate AD-tSVF were listed, and publications referring to such devices were summarized. Recent review manuscripts were also systematically evaluated and included. Transferring adipose tissues and cells has its roots in plastic, reconstructive, and aesthetic surgery. Micro- and nano-fat is also transferred to other organs and tissues to stimulate regeneration as it contains regenerative cells. Minimal manipulation of the adipose tissue is recently preferred to isolate the regenerative cells without disrupting them from their natural environment. The number of patients in the follow-up studies are recently increasing. The duration of follow up is also increasing with favorable outcomes from the short- to mid-term. There are however variations for mean age and the severity of knee OA patients between studies. Positive outcomes are related to the higher number of cells in the AD-tSVF. Repetition of injections and concomitant treatments such as combining the AD-tSVF with platelet rich plasma or hyaluronan are not solidified. Good results were obtained when combined with arthroscopic debridement and micro- or nano-fracture techniques for small-sized cartilage defects. The optimum pressure applied to the tissues and cells during filtration and purification of the AD-tSVF is not specified yet. Quantitative monitoring of articular joint cartilage regeneration by ultrasound, MR, and synovial fluid analysis as well as with second-look arthroscopy could improve our current knowledge on AD-tSVF treatment in knee OA. AD-tSVF isolation techniques and technologies have the potential to improve knee OA treatment. The duration of centrifugation, filtration, washing, and purification should however be standardized. Using gravity-only for isolation and filtration could be a reasonable approach to avoid possible complications of other methodologies.

Strategies to Convert Cells into Hyaline Cartilage: Magic Spells for Adult Stem Cells

Damaged hyaline cartilage gradually decreases joint function and growing pain significantly reduces the quality of a patient's life. The clinically approved procedure of autologous chondrocyte implantation (ACI) for treating knee cartilage lesions has several limits, including the absence of healthy articular cartilage tissues for cell isolation and difficulties related to the chondrocyte expansion in vitro. Today, various ACI modifications are being developed using autologous chondrocytes from alternative sources, such as the auricles, nose and ribs. Adult stem cells from different tissues are also of great interest due to their less traumatic material extraction and their innate abilities of active proliferation and chondrogenic differentiation. According to the different adult stem cell types and their origin, various strategies have been proposed for stem cell expansion and initiation of their chondrogenic differentiation. The current review presents the diversity in developing applied techniques based on autologous adult stem cell differentiation to hyaline cartilage tissue and targeted to articular cartilage damage therapy.

Micro-fragmented adipose tissue (mFAT) associated with arthroscopic debridement provides functional improvement in knee osteoarthritis: a randomized controlled trial

PURPOSE

Current conservative treatments for knee OA provide limited benefits, with symptoms relief for a short amount of time. Regenerative medicine approaches such as the use of microfragmented adipose tissue (mFAT) showed promising results in terms of durable effects and the possibility to enhance tissue healing and counteract the progression of the pathology. Nevertheless, up to today, the large part of clinical data about mFAT use refers to uncontrolled studies, especially in the surgical setting. The purpose of this study was to evaluate the effectiveness of mFAT applied in association with arthroscopic debridement (AD) for the treatment of knee OA, in terms of symptoms relief and tissue healing.

METHODS

This study is a prospective, randomized controlled clinical trial. 78 patients affected by knee OA grade 3-4 according to KL classification were randomly assigned to AD or AD + mFAT treatment groups. Clinical, radiological and serological assessments were performed at 6 months after treatment. Additional clinical evaluation was performed at the end of the study with an average follow-up of 26.1 ± 9.5 months. VAS, KOOS, WOMAC and SF-12 were also collected at both timepoints, KSS only at 6 months.

RESULTS

Treatment with AD + mFAT improved functional scores at both 6 months (KOOS-PS: + 11.7 ± 20.2 vs + 24.4 ± 22.5, in AD and AD + mFAT, respectively, p = 0.024; KSS: + 14.9 ± 15.9 vs + 24.8 ± 23.5, in AD and AD + mFAT, respectively, p = 0.046) and 24-month follow-ups (KOOS-PS Functional subscale: - 2.0 ± 3.5 vs - 4.7 ± 4.2, in AD and AD + mFAT, respectively, p = 0.012). Lower T2-mapping scores were obtained in AD + mFAT-treated group in medial and lateral condyle compartments (p < 0.001). Slight increase was observed in the levels of a serum biomarker of cartilage deposition (PIIINP) in both groups at 6-month follow-up (p = 0.037).

CONCLUSION

mFAT improves functional outcome and MRI appearance when used in association with AD, therefore supporting its use in the treatment of knee OA in an arthroscopic setting.

Stromal vascular fraction therapy for knee osteoarthritis: a systematic review

Background:

Regenerative cell therapies, such as adipose-derived stromal vascular fraction (SVF), have been postulated as potential treatments for knee osteoarthritis (KOA).

Objectives:

To assess the efficacy and safety of SVF treatment against placebo and other standard therapies for treating KOA in adult patients.

Design:

A systematic review.

Data sources and methods:

We searched the following databases: MEDLINE via PubMed, Epistemonikos, PEDro, DynaMed, TripDatabase, Elsevier via Clinicalkey and Cochrane Controlled Trials Register. We included prospective interventional studies where treatment with SVF in adults with KOA was compared against placebo or other standard therapies, and results were objectively measured with at least one widely recognised osteoarthritis scale.

Results:

Among 266 studies published until May 2021, nine met our inclusion criteria. A total of 239 patients (274 knees) were included in our study. The follow-up ranged from 6 to 24 months. Six studies had a control group (only one being placebo). All studies showed that SVF improved pain and functionality measured, in most cases, with the visual analogue scale and the Western Ontario and McMaster Universities Osteoarthritis Index. In addition, five studies reported an improvement in anatomical structures, as detected in MR images. However, the number of cells contained in SVF varied substantially between different studies, which could induce a comparison bias.

Conclusion:

Although based on a small number of dissimilar studies, SVF was considered a safe treatment for KOA and could be promising in terms of pain, functionality and anatomical structure improvement. However, SVF products need to be standardised, the number of cells homogenised and the use of concomitant treatments reduced to establish proper comparisons.

Registration:

PROSPERO registration number: CRD42021284187.

Clinical Safety and Effectiveness of Adipose-Derived Stromal Cell vs Stromal Vascular Fraction Injection for Treatment of Knee Osteoarthritis: 2-Year Results of Parallel Single-Arm Trials

BACKGROUND

There are currently no disease-modifying treatments available for knee osteoarthritis (OA), although cultured adipose-derived stromal cells (ASCs) have shown promise in experimental models. However, given the regulatory limits on the use of cultured cells in humans, previous trials have focused primarily on the stromal vascular fraction (SVF) intra-articular injection. Therefore, the therapeutic value of ASCs for knee OA remains unknown.

PURPOSE

To study ASC versus SVF intra-articular injection in patients with Kellgren-Lawrence (KL) knee OA grades 2 to 4 in parallel single-arm trials.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 80 patients were enrolled, with 42 (72 knees) receiving ASC intra-articular injection and 38 (69 knees) receiving SVF. Patient-reported outcome measures were assessed at 1, 3, 6, 12, and 24 months using the Knee injury and Osteoarthritis Outcome Score 5 (KOOS5) and pain visual analog scale (VAS). The percentages of patients achieving the minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) were also calculated. Per protocol, a subset of the ASC group received an ASC booster injection after 6 months. A repeated-measures analysis of variance compared results between treatment arms and by KL grade over time.

RESULTS

Patient-reported outcome measures improved substantially after both treatments (P < .05 at all time points), with the ASC group more likely to achieve the MCID (50% vs 24%; P = .01) and PASS (45% vs 24%; P = .04) for the pain VAS and the MCID (43% vs 16%; P = .02) for the KOOS5 at 12 months, although not at 24 months. Knees treated with ASC for KL grade 2/3 OA had significantly superior outcomes compared with those with KL grade 4 OA for the KOOS5 (P = .01) and pain VAS (P = .03), but no such difference was observed in knees treated with SVF. Three patients receiving ASCs (7%; all KL grade 3) sought additional nonoperative treatment by 24 months versus 9 patients receiving SVF (24%; all KL grade 3) (P = .06). ASC booster injections conferred no additional benefit. Notably, patients in the ASC cohort reported more injection-site pain and swelling after the booster injection than after the initial injection (P < .01).

CONCLUSION

This represents the first head-to-head comparison of ASCs and SVF for the treatment of knee OA in humans. ASC and SVF injections both substantially improved knee pain and function at all follow-up time points, although ASC injections demonstrated significantly better improvements with regard to the MCID and PASS for the pain VAS and the MCID for the KOOS5 at 12 months. There appears to be no benefit to a booster ASC injection after initial treatment. Given less donor-site morbidity and equivalent superior outcomes at 2 years, the use of ASCs over SVF in the treatment of knee OA may be warranted.

Non-homologous use of adipose-derived cell and tissue therapies: Osteoarthritis as a case study

Adipose tissue is widely recognized as an abundant and accessible human tissue that serves as a source of cells and extracellular matrix scaffolds for regenerative surgical applications. Increasingly, orthopedic surgeons are turning to adipose tissue as a resource in their treatment of osteoarthritis and related conditions. In the U.S., the regulatory landscape governing the orthopedic surgical utilization of autologous and allogeneic adipose tissue remains complex. This manuscript reviews the Food and Drug Administration's nomenclature and guidance regarding adipose tissue products. Additionally, it surveys recent pre-clinical and clinical trial literature relating to the application of adipose-derived cells and tissues in the treatment of osteoarthritis.

Mesenchymal Stem Cell Mechanisms of Action and Clinical Effects in Osteoarthritis: A Narrative Review

With the insufficient satisfaction rates and high cost of operative treatment for osteoarthritis (OA), alternatives have been sought. Furthermore, the inability of current medications to arrest disease progression has led to rapidly growing clinical research relating to mesenchymal stem cells (MSCs). The availability and function of MSCs vary according to tissue source. The three primary sources include the placenta, bone marrow, and adipose tissue, all of which offer excellent safety profiles. The primary mechanisms of action are trophic and immunomodulatory effects, which prevent the further degradation of joints. However, the function and degree to which benefits are observed vary significantly based on the exosomes secreted by MSCs. Paracrine and autocrine mechanisms prevent cell apoptosis and tissue fibrosis, initiate angiogenesis, and stimulate mitosis via growth factors. MSCs have even been shown to exhibit antimicrobial effects. Clinical results incorporating clinical scores and objective radiological imaging have been promising, but a lack of standardization in isolating MSCs prevents their incorporation in current guidelines.

Characterization of Microfragmented Adipose Tissue Architecture, Mesenchymal Stromal Cell Content and Release of Paracrine Mediators

The use of microfragmented adipose tissue (µFAT) for the treatment of musculoskeletal disorders, especially osteoarthritis (OA), is gaining popularity, following positive results reported in recent case series and clinical trials. Although these outcomes were postulated to rely on paracrine signals, to date, a thorough fingerprint of released molecules is largely missing. The purpose of this study was to first characterize both structure and cell content of unprocessed lipoaspirate (LA) and µFAT, and further identify and frame the array of signaling factors in the context of OA disease, by means of high throughput qRT-PCR for extracellular-vesicle (EV) embedded miRNAs and proteomics for tissue and secreted factors. Cell count showed reduction of blood cells in µFAT, confirmed by histological and flow cytometry analyses, that also showed a conserved presence of structural, endothelial and stromal components and pericytes. In the secretome, 376 and 381 EV-miRNAs in LA and µFAT, respectively, were identified. In particular, most abundant and µFAT upregulated EV-miRNAs were mainly recapitulating those already reported as ASC-EVs-specific, with crucial roles in cartilage protection and M2 macrophage polarization, while only a scarce presence of those related to blood cells emerged. Furthermore, secretome proteomic analysis revealed reduction in µFAT of acute phase factors driving OA progression. Taken together, these results suggest that processing of LA into µFAT allows for removal of blood elements and maintenance of tissue structure and stromal cell populations, and possibly the increase of OA-protective molecular features. Thus, microfragmentation represents a safe and efficient method for the application of adipose tissue properties in the frame of musculoskeletal disorders.

Intra-Articular Injection of Adipose-Derived Stem Cells Ameliorates Pain and Cartilage Anabolism/Catabolism in Osteoarthritis: Preclinical and Clinical Evidences

Background: Osteoarthritis (OA) is the most common joint disorder, lacking disease-modifying treatments. Adipose-derived mesenchymal stem cells (ADSCs) are adult multipotent stromal cells obtained from fat tissue, which holds great potential in treating OA. This study aimed to evaluate the anti-OA efficacy of ADSCs from preclinical and clinical facets and explore the underlying mechanism of action.

Methods:In vivo, a single dose of 5 × 10⁵ ADSCs was injected into the knee joints of monoiodoacetate-induced OA rat model. The levels of metabolic and hypertrophic molecules (MMP13, Collagen II, Collagen X) of chondrocytes were measured by immunohistochemistry. In vitro, cell viability assay was conducted to detect the proliferation ability of chondrocytes treated with ADSCs conditioned medium (ADSCs-CM). Quantitative real-time polymerase chain reaction and Western blot assays were applied to explore the mechanism of action of ADSCs. Moreover, a retrospective analysis was conducted to determine the clinical efficacy and safety of ADSCs on OA patients.

Results: The animal study showed that ADSCs significantly alleviated OA cartilage lesions in rats, as was confirmed by downregulation of the MMP13 and Collagen X and upregulation of the Collagen II. In vitro data showed that ADSCs-CM promoted the proliferation of chondrocytes, and significantly restored the IL-1β-induced abnormal expressions of molecular markers IL-6, Aggrecan, MMP3, MMP13, Collagen II, Collagen X, ADAMTS5, ADAMTS9, SOX6, and SOX9 in chondrocytes. Such regulatory effects of ADSCs-CM on the proliferation and these anabolic, catabolic, and hypertrophic markers of chondrocytes suggested a paracrine-based mode of action of ADSCs. Furthermore, the clinical data showed that ADSCs reduced pain and repaired cartilage damage in OA patients, with no adverse events.

Conclusion: This study demonstrated the anti-OA efficacy, safety, and a paracrine-based mechanism of ADSCs, providing a promising cell-based therapeutic option for OA treatment.

Mid-term prognosis of the stromal vascular fraction for knee osteoarthritis: a minimum 5-year follow-up study

Background

The short-term safety and efficacy of stromal vascular fraction (SVF) in treating knee osteoarthritis (KOA) have been extensively studied but the mid-term and long-term prognoses remain unknown.

Methods

126 KOA patients were recruited and randomly assigned to SVF group and hyaluronic acid (HA) group (control group). The scores of visual analogue scale (VAS) and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) were assessed and compared between the two groups 1, 2, 3, and 5 years after treatment. The endpoint was defined as surgeries related to KOA or clinical scores exceeding the patient acceptable symptom state (PASS).

Results

The VAS and WOMAC scores in the SVF group were significantly better than those in the HA group during the 5-year follow-up after treatment. The average responsive time to SVF treatment (61.52 months) was significantly longer than HA treatment (30.37 months). The adjusted Cox proportional hazards model showed that bone marrow lesion (BML) severity, body mass index (BMI) and treatment were independent risk factors and that the use of SVF reduced the risk of clinical failure by 2.602 times. The cartilage volume was reduced in both the SVF and control groups at 5 years but reduced less in the SVF group.

Conclusions

Up to 5 years after SVF treatment, acceptable clinical state was present for approximately 60% of patients. BML severity and BMI were independent predictors of the prognosis.

Trial Registry: This study was retrospectively registered at Chinses Clinical Trial Registry with identifier ChiCTR2100052818 and was approved by ethics committee of the First Affiliated Hospital of Zhejiang Chinese Medical University, number 2013-X-063.

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.

Insights into the present and future of cartilage regeneration and joint repair

Knee osteoarthritis is the most common joint disease. It causes pain and suffering for affected patients and is the source of major economic costs for healthcare systems. Despite ongoing research, there is a lack of knowledge regarding disease mechanisms, biomarkers, and possible cures. Current treatments do not fulfill patients' long-term needs, and it often requires invasive surgical procedures with subsequent long periods of rehabilitation. Researchers and companies worldwide are working to find a suitable cell source to engineer or regenerate a functional and healthy articular cartilage tissue to implant in the damaged area. Potential cell sources to accomplish this goal include embryonic stem cells, mesenchymal stem cells, or induced pluripotent stem cells. The differentiation of stem cells into different tissue types is complex, and a suitable concentration range of specific growth factors is vital. The cellular microenvironment during early embryonic development provides crucial information regarding concentrations of signaling molecules and morphogen gradients as these are essential inducers for tissue development. Thus, morphogen gradients implemented in developmental protocols aimed to engineer functional cartilage tissue can potentially generate cells comparable to those within native cartilage. In this review, we have summarized the problems with current treatments, potential cell sources for cell therapy, reviewed the progress of new treatments within the regenerative cartilage field, and highlighted the importance of cell quality, characterization assays, and chemically defined protocols.

OUP accepted manuscript

Although successful short-term results of the intra-articular injection of mesenchymal stem cells (MSCs) for the conservative treatment of knee osteoarthritis (OA) have been reported, the mid-term results of the injection of adipose-derived (AD) MSCs remains unknown. We assessed the mid-term safety and efficacy of the intra-articular injection of ADMSCs in patients with knee OA. Eleven patients with knee OA were prospectively enrolled and underwent serial evaluations during a 5-year follow-up of a single intra-articular injection of autologous high-dose (1.0 × 10⁸) ADMSCs. The safety profiles were assessed using the World Health Organization Common Toxicity Criteria. The clinical evaluations included visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores for pain and function, respectively. The radiologic evaluations included chondral defect area and whole-organ magnetic resonance imaging scores (WORMS) by serial magnetic resonance imaging (MRI). Hip-knee-ankle axis (HKAA) and Kellgren-Lawrence (K-L) grades were assessed on simple radiographs. No treatment-related adverse events occurred during the 5-year follow-up. Both VAS and total WOMAC scores improved significantly at 6 months after the injection and until the latest follow-up. Total WORMS was significantly improved until 3 years after the injection. However, the chondral defect size on MRI or other radiologic evaluations did not change significantly. A single intra-articular injection of autologous, high-dose ADMSCs provided safe and clinical improvement without radiologic aggravation for 5 years. Furthermore, structural changes in the osteoarthritic knee showed significant improvement up to 3 years, suggesting a possible option for disease-modifying outpatient treatment for patients with knee OA.

Adipose Tissue-Derived Mesenchymal Stem Cells as a Potential Restorative Treatment for Cartilage Defects: A PRISMA Review and Meta-Analysis

Cartilage defects are a predisposing factor for osteoarthritis. Conventional therapies are mostly palliative and there is an interest in developing newer therapies that target the disease’s progression. Mesenchymal stem cells (MSCs) have been suggested as a promising therapy to restore hyaline cartilage to cartilage defects, though the optimal cell source has remained under investigation. A PRISMA systematic review was conducted utilising five databases (MEDLINE, EMBASE, Cochrane Library, Scopus, Web of Science) which identified nineteen human studies that used adipose tissue-derived MSC (AMSC)-based therapies, including culture-expanded AMSCs and stromal vascular fraction, to treat cartilage defects. Clinical, imaging and histological outcomes, as well as other relevant details pertaining to cartilage regeneration, were extracted from each study. Pooled analysis revealed a significant improvement in WOMAC scores (mean difference: −25.52; 95%CI (−30.93, −20.10); p < 0.001), VAS scores (mean difference: −3.30; 95%CI (−3.72, −2.89); p < 0.001), KOOS scores and end point MOCART score (mean: 68.12; 95%CI (62.18, 74.05)), thus showing improvement. The studies in this review demonstrate the safety and efficacy of AMSC-based therapies for cartilage defects. Establishing standardised methods for MSC extraction and delivery, and performing studies with long follow-up should enable future high-quality research to provide the evidence needed to bring AMSC-based therapies into the market.

Potential New Treatments for Knee OA: A Prospective Review of Registered Trials

We aimed to evaluate potential new treatments for knee osteoarthritis (OA). The National Institute of Health ClinicalTrials.gov database was searched for “Osteoarthritis, Knee”. We found 565 ongoing interventional studies with a total planned enrollment of 111,276 subjects. Ongoing studies for knee OA represent a very small fraction of the registered clinical trials, but they are over a quarter of all knee trials and over two thirds of all OA studies. The most researched topic was arthroplasty, with aspects such as implant design changes, cementless fixation, robotic guidance, pain management, and fast track recovery. Intraarticular injections focused on cell therapies with mesenchymal stem cells sourced from adipose tissue, bone marrow, or umbilical cord. We could see the introduction of the first disease modifying drugs with an impact on knee OA, as well as new procedures such as geniculate artery embolization and geniculate nerve ablation.

A review and update for registered clinical studies of stem cells for non-tumorous and non-hematological diseases

Objective

To provide consultative information on selecting potential indications of stem cells in the treatment of non-tumorous and non-hematopoietic system conditions, we screened the clinical trials on website: http://www.clinicaltrials.gov.

Methods

A literature search was conducted using the National Institute of Health (NIH) website (http://www.clinicaltrials.gov) from May 10th, 2012 to Oct 13th, 2020 with stem cells as an intervention in human trials for non-tumorous and non-hematological conditions. There was no restriction for language, research location, and research race.

Results and conclusion

Search terms initially found a total of 3576 articles. Firstly, 138 terminated or suspended studies were excluded and further 24 repeated studies were excluded. Secondly, 987 tumorous and hematopoietic conditions-related studies were excluded. Lastly, 1218 studies were excluded without stem cell therapy as their primary purpose. A total of 1209 research studies were entered into the analysis and reviewed. The top 4 diseases were about motor system diseases 229 (19.28%). In addition, 206 (17.34%) studies were related to central nervous system (CNS) diseases. 140 (11.78%) were autoimmune diseases or graft-versus-host disease (GVHD) after organ transplantation. 129 (10.86%) were about respiratory system diseases, among them, 44.19% projects were about new coronary pneumonia (NCP). The main cell types used in various diseases are Mesenchymal Stem Cells (MSCs), bone marrow stem cells (BM-SCs), peripheral blood stem cells (PBSCs), hematopoietic stem cells (HSCs), adipose stem cell (ASCs) and precursor cells.

A Comparison of the Capacity of Mesenchymal Stromal Cells for Cartilage Regeneration Depending on Collagen-Based Injectable Biomimetic Scaffold Type

Mesenchymal stromal cells (MSCs) have shown a high potential for cartilage repair. Collagen-based scaffolds are used to deliver and retain cells at the site of cartilage damage. The aim of the work was a comparative analysis of the capacity of the MSCs from human adipose tissue to differentiate into chondrocytes in vitro and to stimulate the regeneration of articular cartilage in an experimental model of rabbit knee osteoarthrosis when cultured on microheterogenic collagen-based hydrogel (MCH) and the microparticles of decellularized porcine articular cartilage (DPC). The morphology of samples was evaluated using scanning electron microscopy and histological staining methods. On the surface of the DPC, the cells were distributed more uniformly than on the MCH surface. On day 28, the cells cultured on the DPC produced glycosaminoglycans more intensely compared to the MCH with the synthesis of collagen type II. However, in the experimental model of osteoarthrosis, the stimulation of the cartilage regeneration was more effective when the MSCs were administered to the MCH carrier. The present study demonstrates the way to regulate the action of the MSCs in the area of cartilage regeneration: the MCH is more conducive to stimulating cartilage repair by the MSCs, while the DPC is an inducer for a formation of a cartilage-like tissue by the MSCs in vitro.