Long-term evaluation of osteoarthritis sheep knee, treated with TGF-β3 and BMP-6 induced multipotent stem cells

A programmable arthritis-specific receptor for guided articular cartilage regenerative medicine

Objective

Investigational cell therapies have been developed as disease-modifying agents for the treatment of osteoarthritis (OA), including those that inducibly respond to inflammatory factors driving OA progression. However, dysregulated inflammatory cascades do not specifically signify the presence of OA. Here, we deploy a synthetic receptor platform that regulates cell behaviors in an arthritis-specific fashion to confine transgene expression to sites characterized by cartilage degeneration.

Methods

An scFv specific for type II collagen (CII) was used to produce a synthetic Notch (synNotch) receptor that enables "CII-synNotch" mesenchymal stromal cells (MSCs) to recognize CII fibers exposed in damaged cartilage. Engineered cell activation by both CII-treated culture surfaces and on primary tissue samples was measured via inducible reporter transgene expression. TGFβ3-expressing cells were assessed for cartilage anabolic gene expression via qRT-PCR. In a co-culture with CII-synNotch MSCs engineered to express IL-1Ra, ATDC5 chondrocytes were stimulated with IL-1α, and inflammatory responses of ATDC5s were profiled via qRT-PCR and an NF-κB reporter assay.

Results

CII-synNotch MSCs are highly responsive to CII, displaying activation ranges over 40-fold in response to physiologic CII inputs. CII-synNotch cells exhibit the capacity to distinguish between healthy and damaged cartilage tissue and constrain transgene expression to regions of exposed CII fibers. Receptor-regulated TGFβ3 expression resulted in upregulation of Acan and Col2a1 in MSCs, and inducible IL-1Ra expression by engineered CII-synNotch MSCs reduced pro-inflammatory gene expression in chondrocytes.

Conclusion

This work demonstrates proof-of-concept that the synNotch platform guides MSCs for spatially regulated, disease-dependent delivery of OA-relevant biologic drugs.

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.

Mesenchymal stem cell-derived exosomes as a promising cell-free therapy for knee osteoarthritis

Osteoarthritis (OA), as a degenerative disease, leads to high socioeconomic burdens and disability rates. The knee joint is typically the most affected and is characterized by progressive destruction of articular cartilage, subchondral bone remodeling, osteophyte formation and synovial inflammation. The current management of OA mainly focuses on symptomatic relief and does not help to slow down the advancement of disease. Recently, mesenchymal stem cells (MSCs) and their exosomes have garnered significant attention in regenerative therapy and tissue engineering areas. Preclinical studies have demonstrated that MSC-derived exosomes (MSC-Exos), as bioactive factor carriers, have promising results in cell-free therapy of OA. This study reviewed the application of various MSC-Exos for the OA treatment, along with exploring the potential underlying mechanisms. Moreover, current strategies and future perspectives for the utilization of engineered MSC-Exos, alongside their associated challenges, were also discussed.

Cell-based therapies have disease-modifying effects on osteoarthritis in animal models. A systematic review by the ESSKA Orthobiologic Initiative. Part 2: bone marrow-derived cell-based injectable therapies

PURPOSE

Aim of this systematic review was to determine if bone marrow-derived cell-based injectable therapies induce disease-modifying effects in joints affected by osteoarthritis (OA) in animal models.

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 animal studies comparing injectable bone marrow-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

Fifty-three studies were included (1819 animals) with an increasing publication trend over time. Expanded cells were used in 48 studies, point-of-care products in 3 studies, and both approaches were investigated in 2 studies. Among the 47 studies presenting results on the disease-modifying effects, 40 studies (85%) reported better results with bone marrow-derived products compared to OA controls, with positive findings evident in 14 out of 20 studies (70%) in macroscopic assessment, in 30 out of 41 studies (73%) in histological assessment, and in 10 out of 13 studies (77%) in immunohistochemical evaluations. Clinical evaluations showed positive results in 7 studies out of 9 (78%), positive imaging results in 11 studies out of 17 (65%), and positive biomarker results in 5 studies out of 10 (50%). While 36 out of 46 studies (78%) reported positive results at the cartilage level, only 3 out of 10 studies (30%) could detect positive changes at the synovial level. The risk of bias was low in 42% of items, unclear in 50%, and high in 8%.

CONCLUSION

This systematic review of preclinical studies demonstrated that intra-articular injections of bone marrow-derived products can induce disease-modifying effects in the treatment of OA, slowing down the progression of cartilage damage with benefits at macroscopic, histological, and immunohistochemical levels. Positive results have been also observed in terms of clinical and imaging findings, as well as in the modulation of inflammatory and cartilage biomarkers, while poor effects have been described on the synovial membrane. These findings are important to understand the potential of bone marrow-derived products and to guide further research to optimise their use in the clinical practice.

LEVEL OF EVIDENCE

II.

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.

Engineering of MSC-Derived Exosomes: A Promising Cell-Free Therapy for Osteoarthritis

Osteoarthritis (OA) is characterized by progressive cartilage degeneration with increasing prevalence and unsatisfactory treatment efficacy. Exosomes derived from mesenchymal stem cells play an important role in alleviating OA by promoting cartilage regeneration, inhibiting synovial inflammation and mediating subchondral bone remodeling without the risk of immune rejection and tumorigenesis. However, low yield, weak activity, inefficient targeting ability and unpredictable side effects of natural exosomes have limited their clinical application. At present, various approaches have been applied in exosome engineering to regulate their production and function, such as pretreatment of parental cells, drug loading, genetic engineering and surface modification. Biomaterials have also been proved to facilitate efficient delivery of exosomes and enhance treatment effectiveness. Here, we summarize the current understanding of the biogenesis, isolation and characterization of natural exosomes, and focus on the large-scale production and preparation of engineered exosomes, as well as their therapeutic potential in OA, thus providing novel insights into exploring advanced MSC-derived exosome-based cell-free therapy for the treatment of OA.

Physical and natural cross-linking approaches on 3D gelatin microspheres for cartilage regeneration

The use of gelatin microspheres (GM) as a cell carrier has been extensively researched. One of its limitation is that it dissolves rapidly in aqueous settings, precluding its use for long-term cell propagation. This circumstance necessitates the use of cross-linking agents to circumvent the constraint. Thus, the current study examines two different methods of cross-linking and their effect on the microsphere's '"physicochemical and cartilage tissue regeneration capacity. Crosslinking was accomplished by physical [Dehydrothermal (DHT)] and natural (Genipin) cross-linking of the 3D gelatin microspheres (GM). We begin by comparing the microstructures of the scaffolds and their long-term resistance to degradation under physiological conditions (in isotonic solution, at 37 °C, pH = 7.4). Infrared spectroscopy indicated that the gelatin structure was preserved after the cross-linking treatments. The cross-linked GM" 'demonstrated good cell adhesion, viability, proliferation, and widespread 3D scaffold colonization when seeded with human bone marrow mesenchymal stem cells (BMSCs). Additionally, the cross-linked microspheres enhanced chondrogenesis, as demonstrated by the data. It was discovered that cross-linked GM increased the expression of cartilage-related genes and the biosynthesis of a glycosaminoglycan-positive matrix as compared to non-crosslinked GM. In comparison, DHT-crosslinked results were significantly enhanced. To summarize, DHT treatment was found to be a superior approach for cross-linking the GM in order to promote better cartilage tissue regeneration.

Preclinical studies and clinical trials on mesenchymal stem cell therapy for knee osteoarthritis: A systematic review on models and cell doses

AIM

To provide a systematic analysis of the study design in knee osteoarthritis (OA) preclinical studies, focusing on the characteristics of animal models and cell doses, and to compare these to the characteristics of clinical trials using mesenchymal stem cells (MSCs) for the treatment of knee OA.

METHOD

A systematic and comprehensive search was conducted using the PubMed, Web of Science, Ovid, and Embase electronic databases for research papers published in 2009-2020 on testing MSC treatment in OA animal models. The PubMed database and ClinicalTrials.gov website were used to search for published studies reporting clinical trials of MSC therapy for knee OA.

RESULTS

In total, 9234 articles and two additional records were retrieved, of which 120 studies comprising preclinical and clinical studies were included for analysis. Among the preclinical studies, rats were the most commonly used species for modeling knee OA, and anterior cruciate ligament transection was the most commonly used method for inducing OA. There was a correlation between the cell dose and body weight of the animal. In clinical trials, there was large variation in the dose of MSCs used to treat knee OA, ranging from 1 × 10⁶ to 200 × 10⁶ cells with an average of 37.91 × 10⁶ cells.

CONCLUSION

Mesenchymal stem cells have shown great potential in improving pain relief and tissue protection in both preclinical and clinical studies of knee OA. Further high-quality preclinical and clinical studies are needed to explore the dose effectiveness relationship of MSC therapy and to translate the findings from preclinical studies to humans.

Small Ruminant Models for Articular Cartilage Regeneration by Scaffold-Based Tissue Engineering

Animal models play an important role in preclinical studies, especially in tissue engineering scaffolds for cartilage repair, which require large animal models to verify the safety and effectiveness for clinical use. The small ruminant models are most widely used in this field than other large animals because they are cost-effective, easy to raise, not to mention the fact that the aforementioned animal presents similar anatomical features to that of humans. This review discusses the experimental study of tissue engineering scaffolds for knee articular cartilage regeneration in small ruminant models. Firstly, the selection of these scaffold materials and the preparation process in vitro that have been already used in vivo are briefly reviewed. Moreover, the major factors influencing the rational design and the implementation as well as advantages and limitations of small ruminants are also demonstrated. As regards methodology, this paper applies principles and methods followed by most researchers in the process of experimental design and operation of this kind. By summarizing and comparing different therapeutic concepts, this paper offers suggestions aiming to increase the effectiveness of preclinical research using small ruminant models and improve the process of developing corresponding therapies.

Type II Collagen-Conjugated Mesenchymal Stem Cells Micromass for Articular Tissue Targeting

The tissue engineering approach in osteoarthritic cell therapy often requires the delivery of a substantially high cell number due to the low engraftment efficiency as a result of low affinity binding of implanted cells to the targeted tissue. A modification towards the cell membrane that provides specific epitope for antibody binding to a target tissue may be a plausible solution to increase engraftment. In this study, we intercalated palmitated protein G (PPG) with mesenchymal stem cells (MSCs) and antibody, and evaluated their effects on the properties of MSCs either in monolayer state or in a 3D culture state (gelatin microsphere, GM). Bone marrow MSCs were intercalated with PPG (PPG-MSCs), followed by coating with type II collagen antibody (PPG-MSC-Ab). The effect of PPG and antibody conjugation on the MSC proliferation and multilineage differentiation capabilities both in monolayer and GM cultures was evaluated. PPG did not affect MSC proliferation and differentiation either in monolayer or 3D culture. The PPG-MSCs were successfully conjugated with the type II collagen antibody. Both PPG-MSCs with and without antibody conjugation did not alter MSC proliferation, stemness, and the collagen, aggrecan, and sGAG expression profiles. Assessment of the osteochondral defect explant revealed that the PPG-MSC-Ab micromass was able to attach within 48 h onto the osteochondral surface. Antibody-conjugated MSCs in GM culture is a potential method for targeted delivery of MSCs in future therapy of cartilage defects and osteoarthritis.

Bone Mesenchymal Stem Cells Contribute to Ligament Regeneration and Graft-Bone Healing after Anterior Cruciate Ligament Reconstruction with Silk-Collagen Scaffold

Anterior cruciate ligament (ACL) reconstruction was realized using a combination of bone mesenchymal stem cells (BMSCs) and silk–collagen scaffold, and an in vivo evaluation of this combination was performed. By combining type I collagen and degummed silk fibroin mesh, silk–collagen scaffolds were prepared to simulate ligament components. BMSCs isolated from bone marrow of rabbits were cultured for a homogenous population and seeded on the silk–collagen scaffold. In the scaffold and BMSC (S/C) group, scaffolds were seeded with BMSCs for 72 h and then rolled and used to replace the ACL in 20 rabbits. In the scaffold (S) group, scaffolds immersed only in culture medium for 72 h were used for ACL reconstruction. Specimens were collected at 4 and 16 weeks postoperatively to assess ligament regeneration and bone integration. HE and immunohistochemical staining (IHC) were performed to assess ligament regeneration in the knee cavity. To assess bone integration at the graft–bone interface, HE, Russell–Movat staining, micro-CT, and biomechanical tests were performed. After 4 weeks, vigorous cell proliferation was observed in the core part of the scaffold in the S/C group, and a quantity of fibroblast-like cells and extracellular matrix (ECM) was observed in the center part of the graft at 16 weeks after surgery. At 4 and 16 weeks postoperatively, the tenascin-C expression in the S/C group was considerably higher than that in the S group (4 w, p < 0.01; 16 w, p < 0.01). Furthermore, bone integration was better in the S/C group than in the S group, with histological observation of trabecular bone growth into the graft and more mineralized tissue formation detected by micro-CT (4 w, bone volume fraction (BV/TV), p = 0.0169, bone mineral density (BMD), p = 0.0001; 16 w, BV/TV, p = 0.1233, BMD, p = 0.0494). These results indicate that BMSCs promote ligament regeneration in the knee cavity and bone integration at the graft–bone interface. Silk–collagen scaffolds and BMSCs will likely be combined for clinical practice in the future.

Post-Adipose-Derived Stem Cells (ADSC) Stimulated by Collagen Type V (Col V) Mitigate the Progression of Osteoarthritic Rabbit Articular Cartilage

Collagen is essential for cartilage adhesion and formation. In the present study, histology, immunofluorescence, morphometry, and qRT-PCR suggested that adipose-derived stem cells (ADSCs) stimulated by type V collagen (Col V) induce a significant increase of type II collagen (Col II) in the degenerative area of surgical-induced osteoarthritic rabbit articular cartilage (OA). In vitro, the effects of Col V on the proliferation and differentiation of ADSC were investigated. The expression of the cartilage-related genes Col2a1 and Acan was significantly upregulated and Pou5fl was downregulated post-ADSC/Col V treatment. Post-ADSC/Col V treatment, in vivo analyses revealed that rabbits showed typical signs of osteoarthritic articular cartilage regeneration by hematoxylin and eosin (H&E) and Safranin O/Fast Green staining. Immunohistochemical staining demonstrated that the volume of Col II fibers and the expression of Col II protein were significantly increased, and apoptosis Fas ligand positive significantly decreased post-ADSC/Col V treatment. In conclusion, the expression of Col II was higher in rabbits with surgical-induced osteoarthritic articular cartilage; hence, ADSC/Col V may be a promising therapeutic target for OA treatment.

Improving Cell Therapy Survival and Anabolism in Harsh Musculoskeletal Disease Environments

Cell therapies are an up and coming technology in orthopedic medicine that has the potential to provide regenerative treatments for musculoskeletal disease. Despite numerous cell therapies showing preclinical success for common musculoskeletal indications of disc degeneration and osteoarthritis, there have been mixed results when testing these therapies in humans during clinical trials. A theory behind the mixed success of these cell therapies is that the harsh microenvironments of the disc and knee they are entering inhibit their anabolism and survival. Therefore, there is much ongoing research looking into how to improve the survival and anabolism of cell therapies within these musculoskeletal disease environments. This includes research into improving cell function under specific microenvironmental conditions known to exist in the intervertebral disc (IVD) and knee environment such as hypoxia, low-nutrient conditions, hyperosmolarity, acidity, and inflammation. This research also includes improving differentiation of cells into desired native cell phenotypes to better enhance their survival and anabolism in the knee and IVD. This review highlights the effects of specific musculoskeletal microenvironmental challenges on cell therapies and what research is being done to overcome these challenges. Impact statement While there has been significant clinical interest in using cell therapies for musculoskeletal pathologies in the knee and intervertebral disc, cell therapy clinical trials have had mixed outcomes. The information presented in this review includes the environmental challenges (i.e., acidic pH, inflammation, hyperosmolarity, hypoxia, and low nutrition) that cell therapies experience in these pathological musculoskeletal environments. This review summarizes studies that describe various approaches to improving the therapeutic capability of cell therapies in these harsh environments. The result is an overview of what approaches can be targeted and/or combined to develop a more consistent cell therapy for musculoskeletal pathologies.

Potential Novel Prediction of TMJ-OA: MiR-140-5p Regulates Inflammation Through Smad/TGF-β Signaling

Temporomandibular joint osteoarthritis (TMJ-OA), mainly exhibit extracellular matrix loss and condylar cartilage degradation, is the most common chronic and degenerative maxillofacial osteoarthritis; however, no efficient therapy for TMJ-OA exists due to the poor understanding of its pathological progression. MicroRNA (miR)-140-5p is a novel non-coding microRNAs (miRNAs) that expressed in osteoarthritis specifically. To investigate the molecular mechanisms of miR-140-5p in TMJ-OA, primary mandibular condylar chondrocytes (MCCs) from C57BL/6N mice were treated with interleukins (IL)-1β or transfected with miR-140-5p mimics or inhibitors, respectively. The expression of matrix metallopeptidase (MMP)-13, miR-140-5p, nuclear factor (NF)-kB, Smad3 and transforming growth factor (TGF)-β3 were examined by western blotting or quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The interaction between the potential binding sequence of miR-140-5p and the 3'-untranslated region (3'UTR) of Smad3 mRNA was testified by dual-luciferase assay. Small Interfering RNA of Smad3 (Si-Smad3) was utilized to further identify the role of Smad3 mediated by miR-140-5p. The data showed MMP13, miR-140-5p and NF-kB increased significantly in response to IL-1β inflammatory response in MCCs, meanwhile, Smad3 and TGF-β3 reduced markedly. Moreover, transfection of miR-140-5p mimics significantly suppressed the expression of Smad3 and TGF-β3 in MCCs, while miR-140-5p inhibitors acted in a converse manner. As the luciferase reporter of Smad3 mRNA observed active interaction with miR-140-5p, Smad3 was identified as a direct target of miR-140-5p. Additionally, the expression of TGF-β3 was regulated upon the activation of Smad3. Together, these data suggested that miR-140-5p may play a role in regulating mandibular condylar cartilage homeostasis and potentially serve as a novel prognostic factor of TMJ-OA-like pathology.