Multiple umbilical cord-derived MSCs administrations attenuate rat osteoarthritis progression via preserving articular cartilage superficial layer cells and inhibiting synovitis

Subchondral injection of human umbilical cord mesenchymal stem cells ameliorates knee osteoarthritis by inhibiting osteoblast apoptosis and TGF-beta activity

BACKGROUND

Osteoarthritis (OA) is a common degenerative disease caused by multiple pathological mechanisms wherein subchondral bone malfunction plays a substantial role. Recently, subchondral (SC) injection of orthobiologics has been attracting growing interest albeit the mainstream delivery method of mesenchymal stem cells (MSCs) is through intra-articular (IA). This study investigates the effect of SC injection of human umbilical cord mesenchymal stem cells (UCMSCs) on OA and its possible therapeutic mechanism compared to IA injection.

METHODS

Male Sprague-Dawley rats with anterior cruciate ligament transection (ACLT) received saline or UCMSC injections via SC or IA. Consecutive injections once a week for three weeks and withdrawal for another four weeks, followed by Radiographical scanning, histopathological, immunohistochemical, and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labelling (TUNEL) staining. Cell counting Kit-8 (CCK-8) assay, alkaline phosphatase (ALP), alizarin red staining (ARS), TUNEL, flow cytometry, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were employed in TNFα-induced MC3T3-E1 cells to illustrate the exact pathogenesis mechanism.

RESULTS

IA and SC UCMSC injections preserved cartilage, synovium, and subchondral bone parameters like trabecular bone volume fraction (BV/TV). SC injection uniquely improved Trabecular separation (Tb.Sp) and Trabecular number (Tb.N). SC and IA injections of UCMSCs demonstrated equivalent efficacy in promoting osteoblastic bone formation and attenuating aberrant angiogenesis of subchondral bone. In addition, we demonstrated that osteoblast apoptosis and Smad2-dependent TGF-beta (TGF-β) are crucial and interactive subchondral bone pathological features in OA. In vivo and vitro studies further revealed that UCMSCs inhibited excessive TGF-β/pSmad2 signaling to regulate aberrant vascularization, osteoblast apoptosis and differentiation imbalance, ultimately maintaining osteochondral homeostasis.

CONCLUSIONS

The efficacy of UCMSCs for treating OA rats via SC injection was equivalent to that of IA; and even superior to IA in terms of subchondral bone phenotype via regulating apoptosis and TGF-β/pSmad2 signaling in osteoblasts, suggesting SC injection of UCMSCs as a potential and promising cell therapy for OA treatment.

Cell-based therapies have disease-modifying effects on osteoarthritis in animal models: A systematic review by the ESSKA Orthobiologic Initiative. Part 3: Umbilical cord, placenta, and other sources for cell-based injectable therapies

PURPOSE

This systematic review aimed to investigate in animal models the presence of disease-modifying effects driven by non-bone marrow-derived and non-adipose-derived products, with a particular focus on umbilical cord and placenta-derived cell-based therapies for the intra-articular injective treatment of osteoarthritis (OA).

METHODS

A systematic review was performed on three electronic databases (PubMed, Web of Science and Embase) according to PRISMA guidelines. The results were synthesised to investigate disease-modifying effects in preclinical animal studies comparing injectable umbilical cord, placenta, and other sources-derived products with OA controls. The risk of bias was assessed using the SYRCLE tool.

RESULTS

A total of 80 studies were included (2314 animals). Cell therapies were most commonly obtained from the umbilical cord in 33 studies and placenta/amniotic tissue in 18. Cell products were xenogeneic in 61 studies and allogeneic in the remaining 19 studies. Overall, 25/27 (92.6%) of studies on umbilical cord-derived products documented better results compared to OA controls in at least one of the following outcomes: macroscopic, histological and/or immunohistochemical findings, with 19/22 of studies (83.4%) show positive results at the cartilage level and 4/6 of studies (66.7%) at the synovial level. Placenta-derived injectable products documented positive results in 13/16 (81.3%) of the studies, 12/15 (80.0%) at the cartilage level, and 2/4 (50.0%) at the synovial level, but 2/16 studies (12.5%) found overall worse results than OA controls. Other sources (embryonic, synovial, peripheral blood, dental pulp, cartilage, meniscus and muscle-derived products) were investigated in fewer preclinical studies. The risk of bias was low in 42% of items, unclear in 49%, and high in 9% of items.

CONCLUSION

Interest in cell-based injectable therapies for OA treatment is soaring, particularly for alternatives to bone marrow and adipose tissue. While expanded umbilical cord mesenchymal stem cells reported auspicious disease-modifying effects in preventing OA progression in animal models, placenta/amniotic tissue also reported deleterious effects on OA joints. Lower evidence has been found for other cellular sources such as embryonic, synovial, peripheral blood, dental-pulp, cartilage, meniscus, and muscle-derived products.

LEVEL OF EVIDENCE

Level II.

Mesenchymal stem cells and their extracellular vesicles: new therapies for cartilage repair

Cartilage is crucial for joints, and its damage can lead to pain and functional impairment, causing financial burden to patients. Due to its weak self-repair, cartilage injury control is a research focus. Cartilage injury naturally with age, but mechanical trauma, lifestyle factors and certain genetic abnormalities can increase the likelihood of symptomatic disease progression. Current treatments for cartilage injury include pharmacological and surgical interventions, but these lack the ability to stop the progression of disease and restore the regeneration of the cartilage. Biological therapies have been evaluated but show varying degrees of efficacy in cartilage regeneration long-term. The mesenchymal stem cell (MSC) therapy attracts attention as it is easily harvested and expanded. Once thought to repair via differentiation, MSCs are now known to secrete extracellular vesicles (EVs) paracrinely. These EVs, rich in bioactive molecules, enable cell communication, boost growth factor secretion, regulate the synthesis and degradation of extracellular matrix (ECM), and modulate inflammation, vital for cartilage repair. However, further research and clinical validation are still required for the application of MSC and MSC-EVs. This review highlights the current state of research on the use of MSC and MSC-EVs in the treatment of cartilage injury. It is hoped that the review in this paper will provide valuable references and inspiration for future researchers in therapeutic studies of cartilage repair.

Mesenchymal Stem Cells Injection Is More Effective Than Hyaluronic Acid Injection in the Treatment of Knee Osteoarthritis With Similar Safety: A Systematic Review and Meta-analysis

PURPOSE

To evaluate the efficacy and safety of intra-articular injection of mesenchymal stem cells (MSCs) versus hyaluronic acid (HA) in the treatment of knee osteoarthritis (KOA).

METHODS

Eligible randomized controlled trials (RCTs) were identified through a search of PubMed, Embase, the Cochrane Library, Web of Science, SinoMed, and CNKI databases from inception to March 2024. For meta-analysis, data on clinical outcomes were measured using visual analog scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and data on cartilage repair were measured using the Whole-Organ Magnetic Resonance Imaging Score (WORMS); data on safety were evaluated by the incidence of adverse events. Two researchers independently read the included literature, extracted data and evaluated the quality, used the Cochrane risk bias assessment tool for bias risk assessment, and used RevMan5.3 software for meta-analysis.

RESULTS

Ten RCTs involving 818 patients with KOA ranging from I to Ⅲ on the Kellgren-Lawrence grading scale were included in this meta-analysis. Meta-analysis results showed that at 12 months, the WOMAC total score (mean difference [MD] = -10.22, 95% confidence interval [CI]: -14.86 to -5.59, P < .0001, Z = 4.32), VAS score (MD = -1.31, 95% CI: -1.90 to -0.73, P < .0001, Z = 4.40); and WORMS score (MD = -26.01, 95% CI: -31.88 to -20.14, P < .001, Z = 8.69) of the MSCs group all decreased significantly (P < .05) compared with the HA control group and reached the minimal clinically important differences. Furthermore, there was no significant difference in the incidence of adverse events (relative risk = 1.54, 95% CI: 0.85-2.79, P = .16, I2 = 0) between the 2 groups (P > .05).

CONCLUSIONS

In terms of efficacy, the clinical effects of intra-articular injection therapy using MSCs for KOA are superior to those of HA, and the cartilage repair effect of MSCs is also markedly better than that of HA. Although the clinical effects varied across time periods, the functional score reached the minimum clinically significant difference at both 6 and 12 months. In terms of safety, adverse reactions mainly manifest as joint pain, swelling, and joint effusion. Both intra-articular injections of MSCs and HA did not result in severe adverse reactions, indicating that MSCs and HA have similar safety profiles.

LEVEL OF EVIDENCE

Level I, meta-analysis of Level I studies.

Efficacy of serum-free cultured human umbilical cord mesenchymal stem cells in the treatment of knee osteoarthritis in mice

BACKGROUND

We investigated the efficacy of intra-articular injection of human umbilical cord mesenchymal stem cells (hUC-MSCs) for the treatment of osteoarthritis (OA) progression in the knee joint. Although many experimental studies of hUC-MSCs have been published, these studies have mainly used fetal bovine serum-containing cultures of hUC-MSCs; serum-free cultures generally avoid the shortcomings of serum-containing cultures and are not subject to ethical limitations, have a wide range of prospects for clinical application, and provide a basis or animal experimentation for clinical experiments.

AIM

To study the therapeutic effects of serum-free hUC-MSCs (N-hUCMSCs) in a mouse model of knee OA.

METHODS

Fifty-five male C57BL/6 mice were randomly divided into six groups: The blank control group, model control group, serum-containing hUC-MSCs (S-hUCMSC) group, N-hUCMSC group and hyaluronic acid (HA) group. After 9 weeks of modeling, the serum levels of interleukin (IL)-1β and IL-1 were determined. Hematoxylin-eosin staining was used to observe the cartilage tissue, and the Mankin score was determined. Immunohistochemistry and western blotting were used to determine the expression of collagen type II, matrix metalloproteinase (MMP)-1 and MMP-13.

RESULTS

The Mankin score and serum IL-1 and IL-1β and cartilage tissue MMP-1 and MMP-13 expression were significantly greater in the experimental group than in the blank control group (P < 0.05). Collagen II expression in the experimental group was significantly lower than that in the blank control group (P < 0.05). The Mankin score and serum IL-1 and IL-1β and cartilage tissue MMP-1 and MMP-13 levels the experimental group were lower than those in the model control group (P < 0.05). Collagen II expression in the experimental group was significantly greater than that in the model control group (P < 0.05).

CONCLUSION

N-hUCMSC treatment significantly alleviate the pathological damage caused by OA. The treatment effects of the S- hUCMSC group and HA group were similar.

Effects of the umbilical cord mesenchymal stem cells in the treatment of knee osteoarthritis: A systematic review and meta-analysis

BACKGROUND

This study aimed to evaluate the effects of umbilical cord mesenchymal stem cells (UC-MSCs) in the treatment of knee osteoarthritis.

METHODS

PubMed, Web of Science, Cochrane Library, Embase, Chinese National Knowledge Infrastructure and Wanfang databases were searched from inception to March 31, 2024. RevMan 5.3 was used to conduct meta-analyses of the final included studies.

RESULTS

Three randomized controlled studies were conducted. Western Ontario and McMaster Universities Osteoarthritis Index was reduced in the UC-MSCs group compared that in to the control group (mean difference: -25.85; 95% confidence interval: -41.50, -10.20; P = .001). Knee Lysholm Score was improved in the UC-MSCs group compared with the control group (mean difference: 18.33; 95% confidence interval: 12.89, 23.77; P < .00001). Egger test showed P = .583, indicating no publication bias. Sensitivity analysis indicated that the results were stable.

CONCLUSION

Intra-articular injection of UC-MSCs improved function and reduced pain in patients with knee osteoarthritis. However, the number of included studies was small and more studies are needed to confirm this.

Decadal analysis of efficacy and safety profiles of mesenchymal stem cells from varied sources in knee osteoarthritis patients: A systematic review and network meta-analysis

OBJECTIVE

Knee Osteoarthritis (KOA) is a debilitating degenerative joint ailment afflicting millions of patients. Numerous studies have assessed the efficacy of mesenchymal stem cells (MSCs) derived from various sources for KOA treatment, yet direct comparisons are scarce and inconsistent. Furthermore, network meta-analysis (NMA) conclusions require updating, while the safety of MSCs therapy remains contentious. This study evaluates therapeutic approaches involving MSCs from different sources in patients with KOA through randomized controlled trials (RCTs) and cohort studies. The objective is to compare the effectiveness and safety of MSCs strategies from various sources for KOA treatment.

METHODS

A systematic literature review was conducted to identify RCTs and cohort studies comparing different sources of MSCs in KOA patients. A randomized effects network meta-analysis was used to concurrently evaluate both direct and indirect comparisons across all protocols.

RESULTS

The NMA included 16 RCTS and reported 1005 participants. Adipose-derived mesenchymal stem cells (AD-MSCs) were the most effective treatment, showing significant improvements in the Visual Analogue Scale (VAS), the Short Form 36 (SF-36 scale), the International Knee Literature Committee Knee Evaluation Scale (IKDC subjective scores), and the Knee Injury and OA Outcome Score (KOOS). The probabilities are P = 85.3, P = 70.5, P = 88 and P = 87, respectively. Compared with placebo, AD-MSCs resulted in a VAS Score (SMD 0.97; 95%CI 0.37, 1.57), IKDC subjective scores (SMD -0.71; 95%CI -1.20, -0.21) was significantly reduced. Umbilical cord-derived mesenchymal stem cells (UC-MSCs) showed significant improvements in the University of Western Ontario and McMaster University OA (WOMAC) (P = 91.4). Compared with placebo, UC-MSCs had a higher WOMAC Score (SMD 1.65; 95%CI 0.27, 3.03) and ranked first. Compared with MSCs, placebo emerged as the safer option (P = 74.9), with a notable reduction in AEs associated with HA treatment (RR 0.77; 95%CI 0.61, 0.97). AD-MSCs were found to have the least favorable impact on AEs with a probability of P = 13.3.

CONCLUSIONS

This network meta-analysis established that MSCs offer pain relief and enhance various knee scores in KOA patients compared to conventional treatment. It also identifies other therapeutic avenues warranting further exploration through high-quality studies. Nonetheless, it underscores the necessity to emphasize the potential complications and safety concerns associated with MSCs.

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.

Research and publication trends on knee osteoarthritis and cellular senescence: a bibliometric analysis

Background: Cellular senescence is associated with age-related pathological changes, senescent cells promote the development of knee osteoarthritis. A better understanding between knee osteoarthritis and cellular senescence may enhance the effectiveness of therapies that aim to slow or stop the progression of this disease. Purpose: This study aimed to systematically analyze and visualize the publication trends, research frontiers and current research hotspots of knee osteoarthritis and cellular senescence by using bibliometrics. Methods: The publication search was performed on the Web of Science Core Collection database for documents published from 1992 to 2023. VOSviewer, Citespace, R package Bibliometrix and Microsoft Office Excel were used to study the characteristics of the publications. The publication number, countries, institutions, authors, journals, citations and co-citations, keywords were analyzed. Results: A total of 1,074 publications were analyzed, with an average annual growth rate of 29.89%. United States accounted for the biggest contributor, ranked first in publications and citations. Publications of this field were published in 420 journals, OSTEOARTHRITIS and CARTILAGE was the most influential. A total of 5,657 authors contributed to this research. The most productive author was Lotz, MK (n = 31, H-index = 22, Total citation = 2,619), followed by Loeser, R.F (n = 16, H-index = 14, Total citation = 2,825). However, the collaboration between authors was relatively weak. Out of the 1,556 institutions involved, 60% were from the United States. Scripps Research ranked first with 25 papers and a total of 2,538 citations. The hotspots of this field had focused on the pathomechanisms (e.g., expression, inflammation, apoptosis, autophagy, oxidative stress) and therapeutics (e.g., stem cell, platelet-rich plasma, transplantation, autologous chondrocytes, repair), and the exploration of Senolytics might be the important direction of future research. Conclusion: Research on the cross field of knee osteoarthritis and cellular senescence is flourishing. Age-related pathomechanism maps of various cells in the joint and the targeted medicines for the senescent cells may be the future trends. This bibliometric study provides a comprehensive analysis of this cross field and new insights into future research.

Therapeutic effects of different intervention forms of human umbilical cord mesenchymal stem cells in the treatment of osteoarthritis

Osteoarthritis (OA) is a common and disabling disease. For advanced OA, surgical treatment is still the main treatment. Human umbilical cord mesenchymal stem cells (hUC-MSCs) are self-regenerative pluripotent cells, that coordinate cartilage regeneration by secreting various trophic factors, which adjust the injured tissue environment. hUC-MSCs secret extracellular vesicles and participates in OA treatment by transmitting bioactive molecules related to migration, proliferation, apoptosis, inflammatory reaction, extracellular matrix synthesis and cartilage repair. In addition, the combination of multiple substances represented by cartilage matrix and hUC-MSCs also have a significant synergistic effect on OA treatment. Because hUC-MSCs have shown considerable promise in cartilage repair, some scholars have proposed transplanting mesenchymal stem cells into damaged cartilage to delay OA progression. This article reviews the application of hUC-MSCs as a treatment for OA. With the continuous development of routine clinical applications, more reliable intervention modalities for hUC-MSCs in OA treatment will be discovered for the time to come.

Etanercept embedded silk fibroin/pullulan hydrogel enhance cartilage repair in bone marrow stimulation

Background: Bone marrow stimulation (BMS) is the most used operative treatment in repairing cartilage defect clinically, but always results in fibrocartilage formation, which is easily worn out and needs second therapy. In this study, we prepared an Etanercept (Ept) embedded silk fibroin/pullulan hydrogel to enhance the therapeutic efficacy of BMS. Methods: Ept was dissolved in silk fibroin (SF)-tyramine substituted carboxymethylated pullulan (PL) solution and enzyme crosslinked to obtain the Ept contained SF/PL hydrogel. The synergistical effect of SF/PL hydrogel and Ept was verified by rabbit osteochondral defect model. The mechanism of Ept in promoting articular cartilage repair was studied on human osteoarthritic chondrocytes (hOACs) and human bone marrow mesenchymal stromal cells (hBMSCs) in vitro, respectively. Results: At 4 and 8 weeks after implanting the hydrogel into the osteochondral defect of rabbit, histological analysis revealed that the regenerated tissue in Ept + group had higher cellular density with better texture, and the newly formed hyaline cartilage tissue was seamlessly integrated with adjacent native tissue in the Ept + group. In cellular experiments, Ept treatment significantly promoted both gene and protein expression of type II collagen in hOACs, while decreased the protein levels of metalloproteinase (MMP)-13 and a disintegrin and metalloprotease with thrombospondin motifs 5 (ADAMTS5); alcian blue staining, type II collagen and aggrecan stainings showed that addition of Ept significantly reversed the chondrogenesis inhibition effect of tumor necrosis factor alpha (TNF-α) on hBMSCs. Conclusion: BMS could be augmented by Ept embedded hydrogel, potentially by regulating the catabolic and anabolic dynamics in adjacent chondrocytes and enhancement of BMSCs chondrogenesis.

Perinatal Tissue-Derived Allografts and Stromal Cells for the Treatment of Knee Osteoarthritis: A Review of Preclinical and Clinical Evidence

OBJECTIVE

The use of perinatal-derived tissues and mesenchymal stromal cells (MSCs) as alternative treatment options to corticosteroid and hyaluronic acid injections has been gaining popularity. However, their ability to attenuate osteoarthritic (OA) symptoms while also slowing the progression of the disease remains controversial. Thus, the objective of this article is to summarize the results from both preclinical and clinical studies evaluating the efficacy of perinatal-derived tissue allografts and MSCs for the treatment of OA.

DESIGN

A comprehensive literature search was conducted on databases including Pubmed, ScienceDirect, and Google Scholar beginning in March 2020 for both preclinical and clinical studies evaluating perinatal-derived tissues and MSCs in OA. Eighteen studies met the inclusion criteria and were used for this review.

RESULTS

Both animal models and early human clinical trials demonstrated that perinatal tissues could reduce joint inflammation and pain as well as improve range of motion and function in OA. Perinatal tissue-derived MSCs in animal studies have shown the potential to support chondrocyte proliferation while also decreasing inflammatory gene and protein expression. Limited clinical results suggest perinatal tissue-derived MSC sources may also be a viable alternative or adjunct to hyaluronic acid in reducing pain and symptoms in an arthritic joint.

CONCLUSIONS

Perinatal tissue-derived allografts and MSCs have promise as potential therapeutics for mitigating OA progression. However, further research is warranted to fully define the therapeutic mechanism(s) of action and safety of these biological therapies.

Estrogen Facilitates the Healing of Diabetic Wounds via Ameliorating the Function of Bone Marrow Mesenchymal Stem Cells

We inted to elucidate the impacts of estrogen on the bone marrow-originated endothelial progenitor cells (BM-EPC) and mesenchymal stem cells (BM-MSC) as well as on diabetic wound healing. The skin injury models were established using the diabetic mice (db+/db+) and non-diabetic vector mice and then treated with estrogen-based or placebo-based cream. On the 5th day following injury, BM cells were collected for quantification of EPCs and MSCs and colony-forming units along with analysis of wound healing rate and densities of blood vessels and scars following whole-body perfusion. EPCs were identified through staining of VEGFR1 and CD34 by immunohistochemistrical analyses. In contrast to placebo, treatment with estrogen significantly intensified the colony formation of EPC and MSC, and further promoted the viability and proliferation potential of cells. Meanwhile, estrogen-treated mice exhibited increased recruitment of EPC to the diabetic wounds along with increased vascular density. Additionally, on day 6 after injury, estrogen significantly accelerated wound healing, which was mediated by the enhanced collagen deposition through boosting MSC activation and differentiation, resulting in elevated scar density. In conclusion, estrogen prompts wound healing of diabetic mice via ameliorating the function of BM-derived EPC and MSC, so as to accelerate the neovascularization at the sites of wounds in diabetic mice.

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.

Umbilical Cord Mesenchymal Stromal Cells for Cartilage Regeneration Applications

Chondropathies are increasing worldwide, but effective treatments are currently lacking. Mesenchymal stromal cell (MSCs) transplantation represents a promising approach to counteract the degenerative and inflammatory environment characterizing those pathologies, such as osteoarthritis (OA) and rheumatoid arthritis (RA). Umbilical cord- (UC-) MSCs gained increasing interest due to their multilineage differentiation potential, immunomodulatory, and anti-inflammatory properties as well as higher proliferation rates, abundant supply along with no risks for the donor compared to adult MSCs. In addition, UC-MSCs are physiologically adapted to survive in an ischemic and nutrient-poor environment as well as to produce an extracellular matrix (ECM) similar to that of the cartilage. All these characteristics make UC-MSCs a pivotal source for a stem cell-based treatment of chondropathies. In this review, the regenerative potential of UC-MSCs for the treatment of cartilage diseases will be discussed focusing on in vitro, in vivo, and clinical studies.

Elder Mice Exhibit More Severe Degeneration and Milder Regeneration in Temporomandibular Joints Subjected to Bilateral Anterior Crossbite

Temporomandibular joints (TMJs) have a biomechanical relationship with dental occlusion. Aberrant occlusion initiates degenerative remodeling responses in TMJ condyles. Aging is a promoting factor of osteoarthritis (OA) development. The aim of this study was to assess the effect of aging on degenerative remodeling in TMJ condyles in response to occlusal biomechanical stimulation caused by the installation of aberrant prostheses and observe rehabilitation after their removal. The experiments involved 84 female C57BL/6J mice (42 at 6 weeks old and 42 at 28 weeks old). A bilateral anterior crossbite (BAC) model was developed, and the TMJs were sampled at 3, 7, and 11 weeks. BAC was removed at 7 weeks in a subset of mice, which accepted BAC treatment at 6 week of age, and maintained for another 4 weeks after BAC removal. TMJ changes were assessed with micro-CT, histomorphology, immunohistochemistry (IHC), and immunofluorescence staining assays. The results showed that BAC induced typical OA-like TMJ lesions that were more severe in the elder groups as evaluated by the acellular zones, clustered chondrocytes, fissures between cartilage and subchondral bone, reductions in matrix amount and the cartilage thickness as revealed by histomorphological measurements, and subchondral bone loss as detected on micro-CT images. IHC indicated significant increases in cleaved caspase-3-expressing cells and decreases in ki67-positive cells in the BAC groups. There were obvious age-dependent changes in the numbers of superficial zone cells and CD90-expressing cells. Supportively, cleaved caspase-3-expressing cells obviously increased, while ki67-expressing cells significantly decreased with aging. In the elder BAC groups, the superficial zone cells such as CD90-expressing cells were greatly reduced. At 11 weeks, the superficial zone cells were almost non-existent, and there were clear serrated injuries on the cartilage surface. BAC removal attenuated the degenerative changes in the condylar cartilage and subchondral bone. Notably, the rescue effect was more pronounced in the younger animals. Our findings demonstrate the impacts of aging on both TMJ degenerative changes in response to BAC and regenerative changes following BAC removal. The reduced number of chondro-progenitor cells in aged TMJ cartilage provides an explanation for this age-related decline in TMJ rehabilitative behaviors.

Tropoelastin improves adhesion and migration of intra-articular injected infrapatellar fat pad MSCs and reduces osteoarthritis progression

Intra-articular injection of mesenchymal stem cells (MSCs) is a promising strategy for osteoarthritis (OA) treatment. However, more and more studies reveal that the injected MSCs have poor adhesion, migration, and survival in the joint cavity. A recent study shows that tropoelastin (TE) regulates adhesion, proliferation and phenotypic maintenance of MSCs as a soluble additive, indicating that TE could promote MSCs-homing in regenerative medicine. In this study, we used TE as injection medium, and compared it with classic media in MSCs intra-articular injection such as normal saline (NS), hyaluronic acid (HA), and platelet-rich plasma (PRP). We found that TE could effectively improve adhesion, migration, chondrogenic differentiation of infrapatellar fat pad MSCs (IPFP-MSCs) and enhance matrix synthesis of osteoarthritic chondrocytes (OACs) in indirect-coculture system. Moreover, TE could significantly enhance IPFP-MSCs adhesion via activation of integrin β1, ERK1/2 and vinculin (VCL) in vitro. In addition, intra-articular injection of TE-IPFP MSCs suspension resulted in a short-term increase in survival rate of IPFP-MSCs and better histology scores of rat joint tissues. Inhibition of integrin β1 or ERK1/2 attenuated the protective effect of TE-IPFP MSCs suspension in vivo. In conclusion, TE promotes performance of IPFP-MSCs and protects knee cartilage from damage in OA through enhancement of cell adhesion and activation of integrin β1/ERK/VCL pathway. Our findings may provide new insights in MSCs intra-articular injection for OA treatment.

Accentuating the sources of mesenchymal stem cells as cellular therapy for osteoarthritis knees-a panoramic review

The large economic burden on the global health care systems is due to the increasing number of symptomatic osteoarthritis (OA) knee patients whereby accounting for greater morbidity and impaired functional quality of life. The recent developments and impulses in molecular and regenerative medicine have paved the way for inducing the biological active cells such as stem cells, bioactive materials, and growth factors towards the healing and tissue regenerative process. Mesenchymal stem cells (MSCs) act as a minimally invasive procedure that bridges the gap between pharmacological treatment and surgical treatment for OA. MSCs are the ideal cell-based therapy for treating disorders under a minimally invasive environment in conjunction with cartilage regeneration. Due to the worldwide recognized animal model for such cell-based therapies, global researchers have started using the various sources of MSCs towards cartilage regeneration. However, there is a lacuna in literature on the comparative efficacy and safety of various sources of MSCs in OA of the knee. Hence, the identification of a potential source for therapeutic use in this clinical scenario remains unclear. In this article, we compared the therapeutic effects of various sources of MSCs in terms of efficacy, safety, differentiation potential, durability, accessibility, allogenic preparation and culture expandability to decide the optimal source of MSCs for OA knee.

The role of inflammation in mesenchymal stromal cell therapy in osteoarthritis, perspectives for post-traumatic osteoarthritis: a review

OA is a complex and highly prevalent degenerative disease affecting the whole joint, in which factors like genetic predisposition, gender, age, obesity and traumas contribute to joint destruction. ∼50-80% of OA patients develop synovitis. OA-associated risk factors contribute to joint instability and the release of cartilage matrix fragments, activating the synovium to release pro-inflammatory factors and catabolic enzymes in turn damaging the cartilage and creating a vicious circle. Currently, no cure is available for OA. Mesenchymal stromal cells (MSCs) have been tested in OA for their chondrogenic and anti-inflammatory properties. Interestingly, MSCs are most effective when administered during synovitis. This review focusses on the interplay between joint inflammation and the immunomodulation by MSCs in OA. We discuss the potential of MSCs to break the vicious circle of inflammation and describe current perspectives and challenges for clinical application of MSCs in treatment and prevention of OA, focussing on preventing post-traumatic OA.

TGF-β1-modified MSC-derived exosomal miR-135b attenuates cartilage injury via promoting M2 synovial macrophage polarization by targeting MAPK6

Osteoarthritis (OA) is the most common joint disease with an unsatisfactory therapy outcome and characterized by the degradation of articular cartilage and synovial inflammation. Here, we isolated bone marrow mesenchymal stem cells (BMSCs) from rat's bone marrow and BMSC-derived exosome (BMSCs-Exo) from BMSCs successfully. MiR-135b was proved to be highly expressed in TGF-β1-stimulated BMSC-derived exosomes (BMSCs-Exo^TGF-β1). Then, our results demonstrated that BMSCs-Exo^TGF-β1 reduced OA-induced upregulation of pro-inflammatory factors in rat's serum and damage in cartilage tissues, which was then reversed by miR-135b decreasing. Subsequently, we found that the OA-resulted M1 polarization of synovial macrophages (SMs) was repressed by BMSCs-Exo^TGF-β1, this effect of BMSCs-Exo^TGF-β1 was limited by miR-135b decreasing. We also proved that M2 polarization of SMs can be induced by miR-135b mimics. Furthermore, we found that the promotory effect of miR-135b and BMSCs-Exo^TGF-β1 on M2 SMs polarization was reversed by increasing of MAPK6. Overall, our data showed that BMSCs-Exo^TGF-β1 attenuated cartilage damage in OA rats through carrying highly expressed miR-135b. Mechanistically, miR-135b promoted M2 polarization of SMs through targeting MAPK6, thus improving cartilage damage. Our study provided a novel regulatory mechanism of BMSCs-Exo in OA development and revealed a new potential treatment target of OA.