Mesenchymal stem cell therapy for osteoarthritis

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.

Endogenous Controls for the Evaluation of Osteoarthritis-Related miRNAs in Extracellular Vesicles from Bone-Marrow-Derived Mesenchymal Stromal Cells and the Impact of Osteoarthritis Synovial Fluid

Bone-marrow-derived stromal cells (BMSCs) have emerged as promising therapeutic option for the treatment of osteoarthritis (OA) due to their tissue regenerative and anti-inflammatory features. BMSCs’ clinical potential is mainly ascribed to their released factors and extracellular vesicles (EVs), whose therapeutic portfolio may be modulated by the environment in vivo or specific priming in vitro. Within the array of molecules shaping EVs’ power, miRNAs are considered privileged players. In this frame, a correct EV-miRNA detection and quantification is mandatory to understand and possibly boost BMSCs potential, either when envisioned as cell therapeutics or when proposed as producer of cell-free and clinical grade EVs. The aim of this study is to identify reliable reference genes (RGs) to study miRNAs in BMSC-EVs cultivated under standard or OA synovial fluid (OA-SF). miR-23a-3p and miR-221-3p emerged as the best candidates, respectively. Moreover, when both conditions were analyzed together, miR-24-3p resulted the most stable RGs, allowing for a sharper comparison of EVs content, further validated on the OA-related miRNA-193b-5p. The different RG stability ranking depending on the culturing conditions, as well as its divergence with respect to adipose (ASCs) and amniotic (hAMSCs) MSCs, confirm that miRNA RG selection in EVs is a mandatory step and that the identification of the most reliable candidate is greatly depending on the cell type and culturing/environmental conditions.

Intra-articular Injection of Cell-laden 3D Microcryogels Empower Low-dose Cell Therapy for Osteoarthritis in a Rat Model

Intra-articular injection of mesenchymal stem cells (MSCs) in an osteoarthritic joint can help slow down cartilage destruction. However, cell survival and the efficiency of repair are generally low due to mechanical damage during injection and a high rate of cell loss. We, thus, investigated an improved strategy for cell delivery to an osteoarthritic joint through the use of three-dimensional (3D) microcryogels. MSCs were seeded into 3D microcryogels. The viability and proliferation of MSCs in microcryogels were determined over 5 d, and the phenotype of MSCs was confirmed through trilineage differentiation tests and flow cytometry. In Sprague Dawley rats with induced osteoarthritis (OA) of the knee joint, a single injection was made with the following groups: saline control, low-dose free MSCs (1 × 10⁵ cells), high-dose free MSCs (1 × 10⁶ cells), and microcryogels + MSCs (1 × 10⁵ cells). Cartilage degeneration was evaluated by macroscopic examination, micro-computed tomographic analysis, and histology. MSCs grown in microcryogels exhibited optimal viability and proliferation at 3 d with stable maintenance of phenotype in vitro. Microcryogels seeded with MSCs were, therefore, primed for 3 d before being used for in vivo experiments. At 4 and 8 wk, the microcryogels + MSCs and high-dose free MSC groups had significantly higher International Cartilage Repair Society macroscopic scores, histological evidence of more proteoglycan deposition and less cartilage loss accompanied by a lower Mankin score, and minimal radiographic evidence of osteoarthritic changes in the joint compared to the other two groups. In conclusion, intra-articular injection of cell-laden 3D microcryogels containing a low dose of MSCs can achieve similar effects as a high dose of free MSCs for OA in a rat model. Primed MSCs in 3D microcryogels can be considered as an improved delivery strategy for cell therapy in treating OA that minimizes cell dose while retaining therapeutic efficacy.

Induced pluripotent stem cell-derived mesenchymal stem cells deliver exogenous miR-105-5p via small extracellular vesicles to rejuvenate senescent nucleus pulposus cells and attenuate intervertebral disc degeneration

Background

Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) have emerged as a promising new therapeutic strategy for intervertebral disc degeneration (IVDD). However, the drawbacks of MSCs, including their invasive access, the donor age, and their limited proliferative capacity, hinder the quantity and quality of MSC-sEVs. Induced pluripotent stem cell-derived MSCs (iMSCs) provide an indefinite source of MSCs with well-defined phenotype and function. This study aimed to investigate the therapeutic effect of sEVs derived from iMSC (iMSC-sEVs) on IVDD and explore the underlying molecular mechanisms.

Methods

IVDD models were established by puncturing discs from the tails of rats. Then, iMSC-sEVs were injected into the punctured discs. The degeneration of punctured discs was assessed using MRI and HE and immunofluorescence staining. The age-related phenotypes were used to determine the effects of iMSC-sEVs on senescent nucleus pulposus cells (NPCs) in vitro. Western blotting was used to detect the expression of Sirt6. miRNA sequencing analysis was used to find miRNAs that potentially mediate the activation of Sirt6.

Results

After intradiscally injecting iMSC-sEVs, NPC senescence and IVDD were significantly improved. iMSC-sEVs could rejuvenate senescent NPCs and restore the age-related function by activating the Sirt6 pathway in vitro. Further, microRNA sequence analysis showed that iMSC-sEVs were highly enriched in miR-105-5p, which played a pivotal role in the iMSC-sEV-mediated therapeutic effect by downregulating the level of the cAMP-specific hydrolase PDE4D and could lead to Sirt6 activation.

Conclusion

iMSC-sEVs could rejuvenate the senescence of NPCs and attenuate the development of IVDD. iMSC-sEVs exerted their anti-ageing effects by delivering miR-105-5p to senescent NPCs and activating the Sirt6 pathway. Our findings indicate that iMSCs are a promising MSC candidate for obtaining sEVs on a large scale, while avoiding several defects related to the present applications of MSCs, and that iMSC-sEVs could be a novel cell-free therapeutic tool for the treatment of IVDD.

Factors Influencing Clinical and MRI Outcomes of Mesenchymal Stem Cell Implantation With Concomitant High Tibial Osteotomy for Varus Knee Osteoarthritis

Background

Cartilage repair procedures using mesenchymal stem cells (MSCs) can provide superior cartilage regeneration in the medial compartment of the knee joint when high tibial osteotomy (HTO) is performed for varus knee osteoarthritis (OA). However, few studies have reported the factors influencing the outcomes of MSC implantation with concomitant HTO.

Purpose

To investigate the outcomes of MSC implantation with concomitant HTO and to identify the prognostic factors that are associated with the outcomes.

Study Design

Case series; Level of evidence, 4.

Methods

A total of 71 patients (75 knees) were retrospectively evaluated after MSC implantation with concomitant HTO. Clinical and radiological outcomes were evaluated, and magnetic resonance imaging (MRI) was used to assess cartilage regeneration. Statistical analyses were performed to determine the effect of different factors on clinical, radiographic, and MRI outcomes.

Results

Clinical and radiographic outcomes improved significantly from preoperatively to final follow-up (P < .001 for all), and overall cartilage regeneration was encouraging. Significant correlations were found between clinical and MRI outcomes. However, radiographic outcomes were not significantly correlated with clinical or MRI outcomes. Patient age and number of MSCs showed significant correlations with clinical and MRI outcomes. On multivariate analyses, patient age and number of MSCs showed high prognostic significance with poor clinical outcomes.

Conclusion

MSC implantation with concomitant HTO provided feasible cartilage regeneration and satisfactory clinical outcomes for patients with varus knee OA. Patient age and number of MSCs were important factors that influenced the clinical and MRI outcomes of MSC implantation with concomitant HTO for varus knee OA.

Directionalities of magnetic fields and topographic scaffolds synergise to enhance MSC chondrogenesis

Mesenchymal stem cell (MSC) chondrogenesis is modulated by diverse biophysical cues. We have previously shown that brief, low-amplitude pulsed electromagnetic fields (PEMFs) differentially enhance MSC chondrogenesis in scaffold-free pellet cultures versus conventional tissue culture plastic (TCP), indicating an interplay between magnetism and micromechanical environment. Here, we examined the influence of PEMF directionality over the chondrogenic differentiation of MSCs laden on electrospun fibrous scaffolds of either random (RND) or aligned (ALN) orientations. Correlating MSCs' chondrogenic outcome to pFAK activation and YAP localisation, MSCs on the RND scaffolds experienced the least amount of resting mechanical stress and underwent greatest chondrogenic differentiation in response to brief PEMF exposure (10 min at 1 mT) perpendicular to the dominant plane of the scaffolds (Z-directed). By contrast, in MSC-impregnated RND scaffolds, greatest mitochondrial respiration resulted from X-directed PEMF exposure (parallel to the scaffold plane), and was associated with curtailed chondrogenesis. MSCs on TCP or the ALN scaffolds exhibited greater resting mechanical stress and accordingly, were unresponsive, or negatively responsive, to PEMF exposure from all directions. The efficacy of PEMF-induced MSC chondrogenesis is hence regulated in a multifaceted manner involving focal adhesion dynamics, as well as mitochondrial responses, culminating in a final cellular response. The combined contributions of micromechanical environment and magnetic field orientation hence will need to be considered when designing magnetic exposure paradigms.

Intra-articular injection of human synovium-derived mesenchymal stem cells in beagles with surgery-induced osteoarthritis

BACKGROUND

Recently, cell-based tissue engineering approaches using mesenchymal stem cells (MSCs) have been used to treat osteoarthritis (OA). However, the efficacy of human synovium-derived MSCs (hSD-MSCs) has not yet been tested in a canine model of OA. The purpose of this study was to investigate the therapeutic effects of intra-articular hSD-MSC injections in a canine OA model.

METHODS

Sixty beagles underwent surgical manipulation to induce OA and received intra-articular injection 4 weeks after surgery. The dogs were divided into five groups (n = 12) according to the injection material: G1, sham group; G2, control group injected with phosphate-buffered saline; G3, G4, and G5, experimental groups injected with different hSD-MSC dosages (G3, 2.4 × 10⁶ cells; G4, 4.8 × 10⁶ cells; G5, 9.6 × 10⁶ cells). Magnetic resonance imaging (MRI) and histopathological and immunohistochemical examinations were performed 6 and 24 weeks after injection.

RESULTS

MRI revealed significant improvements in synovitis 24 weeks after injection in the hSD-MSC-injected groups (G3-G5). Histopathologic analyses showed that cartilage structure and proteoglycan staining were also significantly improved in these groups (G3-G5) 6 weeks after injection and improved further after 24 weeks. Immunohistochemical analysis revealed significant differences in the levels of collagen types I and II between the hSD-injected groups (G3-G5), indicating a similar extracellular matrix (ECM) composition to naïve articular cartilage.

CONCLUSION

Our study demonstrated for the first time that intra-articular hSD-MSC injection ameliorates the progression of canine OA by restoring cartilage, promoting ECM synthesis, and inhibiting the inflammatory response.

Mesenchymal Stem Cell Implantation in Knee Osteoarthritis: Midterm Outcomes and Survival Analysis in 467 Patients

Background

A cell-based tissue engineering approach that uses mesenchymal stem cells (MSCs) has addressed the issue of articular cartilage repair in knees with osteoarthritis (OA).

Purpose

To evaluate the midterm outcomes, analyze the survival rates, and identify the factors affecting the survival rate of MSC implantation to treat knee OA.

Study Design

Case series; Level of evidence, 4.

Methods

We retrospectively evaluated 467 patients (483 knees) who underwent MSC implantation on a fibrin glue scaffold for knee OA with a minimum 5-year follow-up. Clinical outcomes were determined based on the International Knee Documentation Committee (IKDC) and Tegner activity scale results measured preoperatively and during follow-up. Standard radiographs were evaluated using Kellgren-Lawrence grading. Statistical analyses were performed to determine the survival rate and the effect of different factors on the clinical outcomes.

Results

The mean IKDC scores (baseline, 39.2 ± 7.2; 1 year, 66.6 ± 9.6; 3 years, 67.2 ± 9.9; 5 years, 66.1 ± 9.7; 9 years, 62.8 ± 8.5) and Tegner scores (baseline, 2.3 ± 1.0; 1 year, 3.4 ± 0.9; 3 years, 3.5 ± 0.9; 5 years, 3.4 ± 0.9; 9 years, 3.2 ± 0.9) were significantly improved until 3 years postoperatively and gradually decreased from 3- to 9-year follow-up (P < .05 for all, except for Tegner score at 5 years vs 1 year [P = .237]). Gradual deterioration of radiological outcomes according to the Kellgren-Lawrence grade was found during follow-up. Survival rates based on either a decrease in IKDC or an advancement of radiographic OA with Kellgren-Lawrence scores were 99.8%, 94.5%, and 74.5% at 5, 7, and 9 years, respectively. Based on multivariate analyses, older age and the presence of bipolar kissing lesion were associated with significantly worse outcomes (P = .002 and .013, respectively), and a larger number of MSCs was associated with significantly better outcomes (P < .001) after MSC implantation.

Conclusion

MSC implantation provided encouraging outcomes with acceptable duration of symptom relief at midterm follow-up in patients with early knee OA. Patient age, presence of bipolar kissing lesion, and number of MSCs were independent factors associated with failure of MSC implantation.

Stem cell therapy for osteonecrosis of femoral head: Opportunities and challenges

Osteonecrosis of the femoral head (ONFH) is a progressive disease with a complex etiology and unclear pathogenesis, resulting in severe hip pain and dysfunction mainly observed in young patients. Although total hip arthroplasty (THA) is the most effective treatment for patients with ONFH in the terminal stage, the results of THA in young patients or active populations are often not favorable, with some complications related to the prosthesis. With the development of biotechnology, an increasing number of studies pay attention to use of stem cells for the treatment of ONFH. Stem cells are characterized by the ability to self-renew and differentiate into multiple cell types, including differentiation into osteoblasts and endothelial cells to mediate bone repair and angiogenesis. Furthermore, stem cells can offer growth factors to promote blood supply in the necrotic regions by paracrine effects. Therefore, stem cell therapy has become one of the hip-preserving alternatives for ONFH. This review summarized the current trends in stem cell therapy for ONFH, from clinical applications to related basic research, and showed that an increasing number of studies have confirmed the effectiveness of stem cell therapy in ONFH. However, many unsolved problems and challenges in practical applications of stem cell therapy still exist, such as patient selection, standardized procedures, safety assessment, and the fate of transplanted cells in the body. Additional studies are required to find ideal cell sources, appropriate transplantation methods, and the optimal number of cells for transplantation.

Intra-articular delivery of umbilical cord-derived mesenchymal stem cells temporarily retard the progression of osteoarthritis in a rat model

AIM

Mesenchymal stem cell (MSC)-based therapy is being explored in treating osteoarthritis (OA). Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) are least reported. In this study, we investigated the effects of single intra-articular injections of hUC-MSCs on a rat OA model.

METHOD

hUC-MSCs were isolated from the Wharton's jelly of the human umbilical cord and identified. Eighteen Sprague-Dawley rats were used for the OA model. All rats were divided into 3 groups: hyaluronic acid (HA)+MSCs (n = 6), HA (n = 6), and control group (n = 6). One by 10⁶ hUC-MSCs in 100 μL HA, 100 μL HA or 100 μL saline were injected into the knee joint 4 weeks post-surgery as a single dose. Cartilage degeneration was evaluated at 6 and 12 weeks after treatment with macroscopic examination, micro-computed tomography analysis, behavioral analysis, and histology.

RESULTS

At 6 weeks, the HA + MSCs group had a significantly better International Cartilage Repair Society score in the femoral condyle compared to the HA and control groups. Histological analysis also showed more proteoglycan and less cartilage loss, with lower modified Mankin score in the HA + MSCs group. However, at 12 weeks there were no significant differences between groups from macroscopic examination and histological analysis. Subchondral bone sclerosis of the medial femoral condyle and behavioral tests showed no significant differences between groups at 6 and 12 weeks.

CONCLUSION

These findings indicate that single injection of hUC-MSCs can have temporary effects on decelerating the progression of cartilage degeneration in OA rats, but may not inhibit OA progression in the long-term.

Osseointegration of osteoporotic bone implants: Role of stem cells, Silica and Strontium - A concise review

Osteoporotic fracture treatment has become a skeletal reconstructive challenge due to accelerated bone turnover and impaired bone regeneration potential. Poor osseointegration ability of the osteoporotic bone usually results in implant pull out and failure. Adoption of conventional bone fracture treatment strategies like autografts and allografts have limited applications in such pathological conditions. Hence biomaterials functionalised with therapeutic ions or drugs may be adopted to aid the delivery of therapeutic factors at the defect site to promote bone healing and implant integration, towards functional restoration of the fractured bone. This concise review narrates on improving the osseointegration ability of biomaterials using functional ions like Silica and Strontium. Silica based bone substitutes are known to promote bone healing in non pathological conditions. Further, Strontium based drugs show significant effects in the prevention and treatment of osteoporotic bones. In addition, stem cell therapy has become the focus of orthopaedic research attributed to its ability to restore and accelerate the bone healing process, but the clinical application of stem cells in osteoporotic condition is scarce. Present review suggests a novel strategy of combining the therapeutic potential of functional ions like Silica, Strontium and stem cells within a single implant unit to facilitate osseointegration and osteogenesis, so as to reduce the chances of implant rejection/pull out and encourage osteoporotic bone re-union.

New Advances in Stem Cell Therapy for Osteonecrosis of the Femoral Head

Osteonecrosis of the femoral head (ONFH) is a common refractory orthopedic disease with multiple etiologies that more frequently occurs in middle-aged and young people. ONFH is the main cause of hip replacement in young patients. Since Professor Hernigou first reported the use of stem cells in the treatment of early stage ONFH, a large number of studies have demonstrated the potential of stem cells in the treatment of adult patients with ONFH. With the rise of interdisciplinary stem cell therapy combined with platelet-rich plasma therapy, gene therapy or other methods have gradually attracted the attention of researchers. This article summarizes the current advances in stem cell therapy for ONFH, as well as the problems and challenges, which may provide reference for further research.

Intraarticular senescent chondrocytes impair the cartilage regeneration capacity of mesenchymal stem cells

Background

Senescent cells exert a significant influence over their surrounding cellular environment. Senescent chondrocytes (SnChos) were found to be accumulated in degenerated cartilage present in joints affected by osteoarthritis. The influence of SnChos on exogenously transplanted stem cells has yet to be reported.

Methods

In this study, we evaluated the interactions between SnChos and bone marrow mesenchymal stem cells (BMSCs) when co-cultured as well as in the intra-articular senescent microenvironment (IASM). The effect of IASM on cartilage regeneration was also assessed.

Results

It was found that a small fraction of SnChos induced BMSC cellular senescence and apoptosis. SnChos also inhibited proliferation, facilitated stemness, and suppressed chondrogenic differentiation of BMSCs. BMSCs induced the apoptosis of SnChos, reduced the proportion of SnChos, stimulated SnChos proliferation, and revealed a bidirectional effect on SnChos inflammaging. IASM significantly suppressed the survival, proliferation, and appropriate differentiation of grafted BMSCs in vivo, all of which impaired cartilage regeneration. Anti-senescence agent ABT-263 was able to partly rescue the cells from the negative effects of SnChos.

Conclusions

The SnChos and BMSCs interacted with each other at cellular senescence, apoptosis, proliferation, differentiation, and cell functions. This interaction impaired the cartilage repair of MSCs. Anti-senescence agent provided a possible solution for this impairment.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1193-1) contains supplementary material, which is available to authorized users.

Perspective on Intra-articular Injection Cell Therapy for Osteoarthritis Treatment

Background

Osteoarthritis (OA), the most common arthritis, is one of the most frequently encountered orthopaedic conditions. As a small number of large joints such as knee and hip are affected in OA, OA is an ideal target for local therapy. Although corticosteroid and hyaluronic acid have been traditionally used for joints through intra-articular (IA) injection, IA injection also provides a minimally invasive route to apply cell therapy to treat OA. IA cell therapy has drawn attention because it may provide regeneration of articular cartilage in addition to palliative anti-inflammatory effects.

Methods

Current progress of IA injection therapy and the author's perspective on this issue are described narratively.

Results

It is too premature to have any conclusion on the eventual efficacy of IA cell therapy concerning regeneration of articular cartilage based on current data. Prospective radiological and histological data from larger numbers of patients are needed to prove cost effectiveness of IA cell therapy.

Conclusions

Expanding research in this field will produce further evidences to provide guidance on the eventual effectiveness of IA cell therapy in the future.

Global research trends in stem cells for osteoarthritis: a bibliometric and visualized study

AIM

There have been increased interests in the use of stems cells in the research of osteoarthritis (OA). The present study aimed to investigate the global status and trends in this field.

METHOD

Publications related to stem cells search in OA from 1994 to 2017 were retrieved from the Science Citation Index-Expanded Web of Science. The source data were studied and indexed using a bibliometric methodology. For visualized study, VOS viewer software was used to conduct bibliographic coupling, co-authorship, co-citation and co-occurrence analysis and to analyze the publication trends in stem cells for OA research.

RESULT

A total of 1933 articles were included. The relative research interests and number of publications were globally increasing per year. The USA made the highest contributions to the global research with the most citations and the highest H-index. The journal Osteoarthritis and Cartilage had the highest publication number. The Tokyo Medical and Dental University, University of Pittsburgh and Shanghai Jiaotong University were the most contributive institutions. Studies could be divided into four clusters: mechanism study, animal study, clinical trials and tissue engineering. The clinical studies were predicted to be the next popular topic in this field.

CONCLUSION

The number of publications about stem cells for OA would be increasing based on the current global trends. The USA was the largest contributor in this field. Most efforts could be put into clinical studies involving mesenchymal stem cells for OA, which may be the next hot spots in OA and stem cells research.

Tissue Engineering in Osteoarthritis: Current Status and Prospect of Mesenchymal Stem Cell Therapy

Osteoarthritis (OA) is the most common form of arthritis. Over the last 20 years, attempts have been made to regenerate articular cartilage to overcome the limitations of conventional treatments. As OA is generally associated with larger and diffuse involvement of articular surfaces and alteration of joint homeostasis, a tissue engineering approach for cartilage regeneration is more difficult than in simple chondral defects. Autologous and allogeneic mesenchymal stem cells (MSCs) have rapidly emerged as investigational products for cartilage regeneration. This review outlines points to consider in MSC-based approaches for OA treatment, including allogeneic MSCs, sources of MSCs, dosages, feasibility of multiple injections, indication according to severity of OA lesion and patient age, and issues regarding implantation versus injection. We introduce possible mechanisms of action of implanted or injected MSCs as well as the immunological aspects of MSC therapy and provide a summary of clinical trials of MSCs in the treatment of OA. Given current knowledge, it is too early to draw conclusions on the ultimate effectiveness of intra-articular application of MSCs in terms of regenerative effects. Further radiological and histological data will be needed, with a larger pool of patients, before this question can be answered.

Intra-Articular Injection of Bone Marrow-Derived Mesenchymal Stem Cells Leading to Better Clinical Outcomes without Difference in MRI Outcomes from Baseline in Patients with Knee Osteoarthritis

Purpose

Bone marrow (BM) is frequently used as a source of mesenchymal stem cells (MSCs) because they have a high potential for differentiation. However, it is unclear whether BM-derived MSCs lead to better clinical and magnetic resonance imaging (MRI) outcomes postoperatively.

Materials and Methods

This meta-analysis compared the clinical and MRI outcomes in patients with knee osteoarthritis (OA) treated with BM-derived MSCs. Eight studies comparing the clinical and MRI outcomes assessed with various measurement tools in patients with knee OA treated with BM-derived MSCs were included.

Results

The range of motion (95% confidence interval [CI], −13.05 to 4.24; p=0.32) and MRI outcomes (95% CI, −0.16 to 1.40; p=0.12) did not differ significantly between the baseline and final follow-up. In contrast, pain (95% CI, 0.89 to 1.87; p<0.001) and functional outcomes (95% CI, 0.70 to 2.07; p<0.001) were significantly improved at the final follow-up when compared to the baseline.

Conclusions

This meta-analysis found no significant difference in the tested range of motion and MRI outcomes between the baseline and the final follow-up in patients treated with BM-derived MSCs, whereas significant functional improvement and pain relief were noted when compared with the baseline. Thus, BM-derived MSCs appear to be a viable alternative for patients with knee OA, although long-term and high-quality randomized controlled trials are needed to confirm the clinical benefits.

The interrelation of osteoarthritis and diabetes mellitus: considering the potential role of interleukin-10 and in vitro models for further analysis

INTRODUCTION

Today, not only the existence of an interrelation between obesity/adipositas and osteoarthritis (OA) but also the association of OA and diabetes mellitus (DM) are widely recognized. Nevertheless, shared influence factors facilitating OA development in DM patients still remain speculative up until now. To supplement the analysis of clinical data, appropriate in vitro models could help to identify shared pathogenetic pathways. Informative in vitro studies could later be complemented by in vivo data obtained from suitable animal models.

MATERIALS AND METHODS

Therefore, this detailed review of available literature was undertaken to discuss and compare the results of currently published in vitro studies focusing on the interrelation between OA, the metabolic syndrome and DM and to propose models to further study the molecular pathways.

RESULTS

The survey of literature presented here supports the hypothesis that the pathogenesis of OA in DM is based on imbalanced molecular pathways with a putative crucial role of antiinflammatory cytokines such as IL-10.

CONCLUSION

Future development of versatile micro-scaled in vitro models such as combining DM and OA on chip could allow the identification of common pathogenetic pathways and might help to develop novel therapeutic strategies.

Exosomes from embryonic mesenchymal stem cells alleviate osteoarthritis through balancing synthesis and degradation of cartilage extracellular matrix

Background

Mesenchymal stem cell therapy for osteoarthritis (OA) has been widely investigated, but the mechanisms are still unclear. Exosomes that serve as carriers of genetic information have been implicated in many diseases and are known to participate in many physiological processes. Here, we investigate the therapeutic potential of exosomes from human embryonic stem cell-induced mesenchymal stem cells (ESC-MSCs) in alleviating osteoarthritis (OA).

Methods

Exosomes were harvested from conditioned culture media of ESC-MSCs by a sequential centrifugation process. Primary mouse chondrocytes treated with interleukin 1 beta (IL-1β) were used as an in vitro model to evaluate the effects of the conditioned medium with or without exosomes and titrated doses of isolated exosomes for 48 hours, prior to immunocytochemistry or western blot analysis. Destabilization of the medial meniscus (DMM) surgery was performed on the knee joints of C57BL/6 J mice as an OA model. This was followed by intra-articular injection of either ESC-MSCs or their exosomes. Cartilage destruction and matrix degradation were evaluated with histological staining and OARSI scores at the post-surgery 8 weeks.

Results

We found that intra-articular injection of ESC-MSCs alleviated cartilage destruction and matrix degradation in the DMM model. Further in vitro studies illustrated that this effect was exerted through ESC-MSC-derived exosomes. These exosomes maintained the chondrocyte phenotype by increasing collagen type II synthesis and decreasing ADAMTS5 expression in the presence of IL-1β. Immunocytochemistry revealed colocalization of the exosomes and collagen type II-positive chondrocytes. Subsequent intra-articular injection of exosomes derived from ESC-MSCs successfully impeded cartilage destruction in the DMM model.

Conclusions

The exosomes from ESC-MSCs exert a beneficial therapeutic effect on OA by balancing the synthesis and degradation of chondrocyte extracellular matrix (ECM), which in turn provides a new target for OA drug and drug-delivery system development.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0632-0) contains supplementary material, which is available to authorized users.

Mesenchymal Stem and Progenitor Cells in Regeneration: Tissue Specificity and Regenerative Potential

It has always been an ambitious goal in medicine to repair or replace morbid tissues for regaining the organ functionality. This challenge has recently gained momentum through considerable progress in understanding the biological concept of the regenerative potential of stem cells. Routine therapeutic procedures are about to shift towards the use of biological and molecular armamentarium. The potential use of embryonic stem cells and invention of induced pluripotent stem cells raised hope for clinical regenerative purposes; however, the use of these interventions for regenerative therapy showed its dark side, as many health concerns and ethical issues arose in terms of using these cells in clinical applications. In this regard, adult stem cells climbed up to the top list of regenerative tools and mesenchymal stem cells (MSC) showed promise for regenerative cell therapy with a rather limited level of risk. MSC have been successfully isolated from various human tissues and they have been shown to offer the possibility to establish novel therapeutic interventions for a variety of hard-to-noncurable diseases. There have been many elegant studies investigating the impact of MSC in regenerative medicine. This review provides compact information on the role of stem cells, in particular, MSC in regeneration.

Deformability of Human Mesenchymal Stem Cells Is Dependent on Vimentin Intermediate Filaments

Mesenchymal stem cells (MSCs) are being studied extensively due to their potential as a therapeutic cell source for many load-bearing tissues. Compression of tissues and the subsequent deformation of cells are just one type physical strain MSCs will need to withstand in vivo. Mechanotransduction by MSCs and their mechanical properties are partially controlled by the cytoskeleton, including vimentin intermediate filaments (IFs). Vimentin IF deficiency has been tied to changes in mechanosensing and mechanical properties of cells in some cell types. However, how vimentin IFs contribute to MSC deformability has not been comprehensively studied. Investigating the role of vimentin IFs in MSC mechanosensing and mechanical properties will assist in functional understanding and development of MSC therapies. In this study, we examined vimentin IFs' contribution to MSCs' ability to deform under external deformation using RNA interference. Our results indicate that a deficient vimentin IF network decreases the deformability of MSCs, and that this may be caused by the remaining cytoskeletal network compensating for the vimentin IF network alteration. Our observations introduce another piece of information regarding how vimentin IFs are involved in the complex role the cytoskeleton plays in the mechanical properties of cells.