Regeneration of hyaline-like cartilage in situ with SOX9 stimulation of bone marrow-derived mesenchymal stem cells

The potential key genes within focal adhesion that regulate mesenchymal stem cells osteogenesis or adipogenesis in microgravity related disuse osteoporosis: an integrated analysis

This study aimed to identify key genes related to focal adhesions (FA) and cells involved in osteoblast (OS) and adipocyte (AD) differentiation in osteoporosis. A mouse model of disuse osteoporosis was made by hindlimbs unloading (HLU)/Tail - suspension. Micro - CT and histological analysis were done, and differentially expressed genes (DEGs) from GSE100930 were analyzed. Soft clustering on GSE80614 OS/AD samples found FA - related candidate genes. protein-protein interaction (PPI) network and cytoHubba's Degree algorithm identified key FA - genes, validated by quantitative polymerase chain reaction (qPCR). Key OS/AD - associated cells were identified by single - cell analysis. The mouse model showed decreased bone density, microstructure damage, increased marrow adiposity, and altered gene expression. Key FA - related genes for osteogenesis (ITGB3, LAMC1, COL6A3, ITGA8, PDGFRB) and adipogenesis (ITGB3, ITGA4, LAMB1, ITGA8, LAMA4) were found and validated. Key cells (chondrocyte, adipocyte, and osteoblast progenitors) are involved in specific pathways, with osteoblast progenitors having stronger interactions. Pseudotime analysis implies differentiation from chondrocyte progenitors to adipocyte, then osteoblast progenitors. This study provides new insights for disuse osteoporosis research.

Deer antler reserve mesenchyme cells modified with miR-145 promote chondrogenesis in cartilage regeneration

Deer antler-derived reserve mesenchyme cells (RMCs) are a promising source of cells for cartilage regeneration therapy due to their chondrogenic differentiation potential. However, the regulatory mechanism has not yet been elucidated. In this study, we analyzed the role of microRNAs (miRNAs) in regulating the differentiation of RMCs and in the post-transcriptional regulation of chondrogenesis and hypertrophic differentiation at the molecular and histological levels. The results showed that RMCs showed typical MSC differentiation potentials. During chondrogenic differentiation, we obtained the expression profile of miRNAs, among which miR- 145 was the most prominent candidate as a key microRNA involved in the balance of chondral and endochondral differentiation. Knockdown of miR-145 promoted chondrogenesis and inhibited hypertrophy differentiation in RMCs. Mechanically, by prediction through online databases combined with dual-luciferase reporter assay, SOX9 was suggested as a target of miR-145. Further validation experiments confirmed that knockdown of miR-145 contributed to the balance between endochondral versus chondral differentiation of RMCs by targeting SOX9. Additionally, RMCs transfected with the miR-145-knockdown-mediated lentiviral vector successfully promoted cartilage regeneration in vivo. In summary, our study suggested that the reciprocal negative feedback between SOX9 and miR-145 was essential for balancing between endochondral versus chondral differentiation of RMCs. Our study suggested that modification of RMCs using miRNAs transduction might be an effective treatment for cartilage defects.

In Vitro Investigation of 3D Printed Hydrogel Scaffolds with Electrospun Tidemark Component for Modeling Osteochondral Interface

Osteochondral (OC) tissue plays a crucial role due to its ability to connect bone and cartilage tissues. To address the complexity of structure and functionality at the bone-cartilage interface, relevant to the presence of the tidemark as a critical element at the bone-cartilage boundary, we fabricated graded scaffolds through sequential 3D printing. The scaffold's bottom layer was based on a gelatin/oxidized alginate mixture enriched with hydroxyapatite (HAp) to create a rougher surface and larger pores to promote osteogenesis. In contrast, the upper layer was engineered to have smaller pores and aimed to promote cartilage tissue formation and mimic the physical properties of the cartilage. An electrospun ε-polycaprolactone (PCL) membrane with micrometer-range pores was incorporated between the layers to replicate the function of tidemark-a barrier to prevent vascularization of cartilage from subchondral bone tissue. In vitro cell studies confirmed the viability of the cells on the layers of the scaffolds and the ability of PCL mesh to prevent cellular migration. The fabricated scaffolds were thoroughly characterized, and their mechanical properties were compared to native OC tissue, demonstrating suitability for OC tissue engineering and graft modeling. The distance of gradient of mineral concentration was found to be 151 µm for grafts and the native OC interface.

The role of NF-κB-SOX9 signalling pathway in osteoarthritis

The nuclear factor-κB (NF-κB) signalling pathway exists in a variety of cells and is involved in the gene regulation of various physiological and pathological processes such as inflammation, immunity, cell proliferation and apoptosis. It has been shown that this signaling pathway is also involved in numerous events associated with osteoarthritis, including chondrocyte catabolism, chondrocyte survival, and synovial inflammation. SRY-related high mobility group-box 9(SOX9) is the "master regulator" of chondrocytes and one of the key transcription factors that maintain chondrocyte phenotype and cartilage homeostasis. NF-κB can positively regulate the expression of SOX9 by directly binding to its promoter region, and play a role in the formation and development of chondrocytes. This article reviews the regulatory effect of the NF-κB-SOX9 signaling axis on osteoarthritis.

Specificities in the Structure of the Cartilage of Patients with Advanced Stages of Developmental Dysplasia of the Hip

Developmental dysplasia of the hip (DDH) presents varying degrees of femoral head dislocation, with severe cases leading to the formation of a new articular surface on the external side of the iliac bone-the neoacetabulum. Despite conventional understanding suggesting otherwise, a tissue resembling hyaline cartilage is found in the neoacetabulum and acetabulum of Crowe III and IV patients, indicating a potential for hyaline cartilage development without mechanical pressure. To test this theory, acetabular and femoral head cartilage obtained from patients with DDH was stained with hematoxylin-eosin and toluidine blue. The immunohistochemical analysis for collagen types II and VI and aggrecan was performed, as well as delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) analysis on a 7.0 T micro-MRI machine. The results obtained from DDH patients were compared to those of the control groups. Hyaline cartilage was found in the neoacetabulum and the acetabulum of patients with DDH. The nature of the tissue was confirmed with both the histological and the MRI analyses. The results of this study proved the presence of hyaline cartilage in patients with DDH at anatomical regions genetically predisposed to be bone tissue and at regions that are not subjected to mechanical stress. This is the first time that the neoacetabular cartilage of patients with advanced stages of DDH has been characterized in detail.

Cartilage-inspired self-assembly glycopeptide hydrogels for cartilage regeneration via ROS scavenging

Cartilage injury represents a frequent dilemma in clinical practice owing to its inherently limited self-renewal capacity. Biomimetic strategy-based engineered biomaterial, capable of coordinated regulation for cellular and microenvironmental crosstalk, provides an adequate avenue to boost cartilage regeneration. The level of oxidative stress in microenvironments is verified to be vital for tissue regeneration, yet it is often overlooked in engineered biomaterials for cartilage regeneration. Herein, inspired by natural cartilage architecture, a fibril-network glycopeptide hydrogel (Nap-FFGRGD@FU), composed of marine-derived polysaccharide fucoidan (FU) and naphthalenephenylalanine-phenylalanine-glycine-arginine-glycine-aspartic peptide (Nap-FFGRGD), was presented through a simple supramolecular self-assembly approach. The Nap-FFGRGD@FU hydrogels exhibit a native cartilage-like architecture, characterized by interwoven collagen fibers and attached proteoglycans. Beyond structural simulation, fucoidan-exerted robust biological effects and Arg-Gly-Asp (RGD) sequence-provided cell attachment sites realized functional reinforcement, synergistically promoted extracellular matrix (ECM) production and reactive oxygen species (ROS) elimination, thus contributing to chondrocytes-ECM harmony. In vitro co-culture with glycopeptide hydrogels not only facilitated cartilage ECM anabolic metabolism but also scavenged ROS accumulation in chondrocytes. Mechanistically, the chondro-protective effects induced by glycopeptide hydrogels rely on the activation of endogenous antioxidant pathways associated with nuclear factor erythroid 2-related factor 2 (NRF2). In vivo implantation of glycopeptide hydrogels successfully improved the de novo cartilage generation by 1.65-fold, concomitant with coordinately restructured subchondral bone structure. Collectively, our ingeniously crafted bionic glycopeptide hydrogels simultaneously rewired chondrocytes' function by augmenting anabolic metabolism and rebuilt ECM microenvironment via preserving redox equilibrium, holding great potential for cartilage tissue engineering.

Bioadhesive and Injectable Hydrogels and Their Correlation with Mesenchymal Stem Cells Differentiation for Cartilage Repair: A Mini-Review

Injectable bioadhesive hydrogels, known for their capacity to carry substances and adaptability in processing, offer great potential across various biomedical applications. They are especially promising in minimally invasive stem cell-based therapies for treating cartilage damage. This approach harnesses readily available mesenchymal stem cells (MSCs) to differentiate into chondrocytes for cartilage regeneration. In this review, we investigate the relationship between bioadhesion and MSC differentiation. We summarize the fundamental principles of bioadhesion and discuss recent trends in bioadhesive hydrogels. Furthermore, we highlight their specific applications in conjunction with stem cells, particularly in the context of cartilage repair. The review also encompasses a discussion on testing methods for bioadhesive hydrogels and direct techniques for differentiating MSCs into hyaline cartilage chondrocytes. These approaches are explored within both clinical and laboratory settings, including the use of genetic tools. While this review offers valuable insights into the interconnected aspects of these topics, it underscores the need for further research to fully grasp the complexities of their relationship.

Effect of recombinant Sox9 protein on the expression of cartilage-specific genes in human dermal fibroblasts cell culture

Introduction: Damage to the hyaline layer of large joints resulting from injuries or age-related changes restricts their mobility. The repair of these disorders is an actual issue in medicine. One of the promising therapies is the usage of cell engineering constructs based on a biodegradable scaffold and a modified cell culture. A frequently used method to modify the proliferation of cell culture for tissue engineering of hyaline cartilage, which makes it possible to introduce an experimental technique into clinical practice, is the application of recombinant proteins that affect chondrogenesis and lead to increase synthesis of extracellular matrix proteins. The goal of this work was to elucidate the effect of the key transcription factor in the chondrogenesis process – Sox9 protein – on the expression of genes responsible for chondrogenesis (Tgfβ3, Sox9, Acan, Comp, Col2a1).

Materials and methods: Human dermal fibroblasts were used as a cell culture; recombinant Sox9 was added at each change of medium; the modification was carried out for 21 days, and difference in gene expression was determined by real-time PCR and -ΔΔCt method.

Results and discussion: To assess the effectiveness of fibroblast modification, we analyzed the changing of expression of genes responsible for chondrogenesis (Tgfß3, Sox9, Col2a1, Acan, Comp). We studied the direct effect of different concentrations of the recombinant Sox9 protein on the proliferation of dermal fibroblasts in the chondrogenic direction. We showed that the addition of the recombinant Sox9 protein in various concentration did not significantly change the expression of both the genes encoding proteins of the extracellular matrix of hyaline cartilage (Acan, Col2a1, Comp) and the genes encoding chondrogenesis inducers (Tgfß3, Sox9).

Conclusion: As a result of the experiments, it was shown that the recombinant Sox9 protein has practically no effect on chondrogenic differentiation and does not significantly change the expression of chondrogenesis genes.

Performance of Colombian Silk Fibroin Hydrogels for Hyaline Cartilage Tissue Engineering

The development and evaluation of scaffolds play a crucial role in the engineering of hyaline cartilage tissue. This work aims to evaluate the performance of silk fibroin hydrogels fabricated from the cocoons of the Colombian hybrid in the in vitro regeneration of hyaline cartilage. The scaffolds were physicochemically characterized, and their performance was evaluated in a cellular model. The results showed that the scaffolds were rich in random coils and β-sheets in their structure and susceptible to various serine proteases with different degradation profiles. Furthermore, they showed a significant increase in ACAN, COL10A1, and COL2A1 expression compared to pellet culture alone and allowed GAG deposition. The soluble portion of the scaffold did not affect chondrogenesis. Furthermore, they promoted the increase in COL1A2, showing a slight tendency to differentiate towards fibrous cartilage. The results also showed that Colombian silk could be used as a source of biomedical devices, paving the way for sericulture to become a more diverse economic activity in emerging countries.

Effects of Bushen Zhuangjin Decoction drug serum on SOX9 expression and Chondrocyte phenotype in vitro

Introduction Bushen Zhuangjin Decoction (BZD), a well-known formulation in Traditional Chinese Medicine, has been widely used for the treatment of osteoarthritis (OA). Due to the poor intrinsic repair capacity of chondrocytes, promoting the proliferation of chondrocytes is an efficient treatment to delay the progression of cartilage degradation.

Hypothesis/Gap Statement Therefore, to explore the regulatory mechanism of Bushen Zhuangjin Decoction in chondrocytes will contribute to the repair of chondrocyte injury in OA, and may serve as a potential therapy for OA diseases.

Aim To investigate the expression and distribution of SOX9 mediated by serum containing Bushen Zhuangjin Decoction (BZD) and its therapeutic effect on chondrocyte injury in rats.

Methodology. The subcultured second-generation rat chondrocytes were randomly divided into four groups, and they were intervened with medium containing different serums, including: blank serum group, low-concentration BZD group, medium-concentration BZD group, and high-concentration BZD group. The viability, proliferation and apoptosis of chondrocytes were detected by MTT assay and flow cytometry. The gene and protein levels of SOX9, aggrecan and type II collagen genes were analysed by qRT-PCR and Western blot analysis. Immunofluorescence staining was used to analyse the expression and distribution of SOX9. Inflammatory factors in different culture mediums of chondrocytes were detected by ELISA.

Results Compared with the control group, the activity of chondrocytes in the BZD drug-containing serum group was significantly enhanced, and the degree of apoptosis was significantly decreased. The gene and protein levels of SOX9, proteoglycan aggrecan and collagen II in chondrocytes increased significantly. The inflammatory factors in the culture medium also decreased significantly. And in the above experiments, the medium concentration group BZD drug-containing serum had the best effect.

Conclusion Our research results show that BZD medicated serum can up-regulate the expression of SOX9, reduce the release of inflammatory factors, and promote changes in the phenotype of chondrocytes, which protects chondrocytes from damage.

Ultrasound-guided intra-articular injection of expanded umbilical cord mesenchymal stem cells in knee osteoarthritis: a safety/efficacy study with MRI data

Aim: This study has the primary objective of studying the effect of Wharton jelly mesenchymal stem cells (WJMSCs) in the treatment of knee osteoarthritis. As a secondary end point, we report on the efficacy of such therapy. Patients and methods: 16 patients with advanced Kellgren stage were treated using two doses of expanded WJMSCs given 1 month apart. Patients were followed for 48 months using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and 12 months using magnetic resonance imaging (MRI). Results: Treatment was well tolerated. One patient developed moderate effusion and one superficial phlebitis. We observed functional and pain improvement at 12 and 48 months (p < 0.0001), with statistically significant improvement on MRI scans at 12 months in cartilage loss, osteophytes, bone marrow lesions, effusion and synovitis (p < 0.01), and highly significant improvement in subchondral sclerosis (p < 0.0001). Conclusion: WJMSCs are safe and potentially effective in producing significant improvement in KOOS and MRI scores when administered intra-articularly in knee osteoarthritis cases under ultrasound guidance.

Tonsil mesenchymal stem cells-derived extracellular vesicles prevent submandibular gland dysfunction in ovariectomized rats

Dry mouth that occurs after menopause significantly reduces the quality of life of the elderly. The extracellular vesicles derived from mesenchymal stem cells are being studied for application in various pathological conditions in the field of tissue regenerative medicine. This study is to investigate the therapeutic effect on salivary gland dysfunction occurring after ovariectomy using tonsil mesenchymal stem cells (T-MSCs)-derived extracellular vesicles. The rats were divided into the following groups: sham-operated rats (SHAM), rats that underwent ovariectomy (OVX), and rats that underwent OVX surgery and were simultaneously injected with T-MSC-derived extracellular vesicles (OVX+EV). The rats were sacrificed 6 weeks after ovariectomy. Estradiol levels decreased in the OVX group compared with those in the SHAM group. Extracellular vesicles had no effect on estradiol levels or estrogen receptor β expression. The evaluation of pro-inflammatory cytokines, TNF-α and IL-6, increased in the OVX group and decreased in the OVX+EV group. The expressions of collagen I and TGFβI increased in the OVX group but decreased in the OVX+EV group. Moreover, to examine submandibular gland function, AQP5 and α-amylase expressions were downregulated in the OVX group, but improved upon exosome injection. In conclusion, T-MSC-derived extracellular vesicles are useful for the prevented submandibular gland dysfunction that occurs after menopause.

RNA isolation from micro-quantity of articular cartilage for quantitative gene expression by microarray analysis

Isolation of quality RNA from articular cartilage has been challenging due to low cellularity and the high abundance of extracellular matrix and proteoglycan proteins. Recently developed methods for isolation of high quality RNA from cartilage are more applicable to larger cartilage specimens typically weighing at least 25 mg. While these methods generate RNA suitable for analysis, they are less successful with smaller tissue inputs. For the study of small focal defect cartilage specimens an improved RNA extraction method is needed. Here we report a protocol for direct RNA isolation from less than 3 mg of wet weight rabbit articular cartilage for quantitative microarray gene profiling. This protocol is useful for identifying differentially expressed genes in chondrocytes following focal cartilage repair and can potentially be adopted for gene expression analysis of cartilage biopsy specimens from human joints.

Methods of Modification of Mesenchymal Stem Cells and Conditions of Their Culturing for Hyaline Cartilage Tissue Engineering

The use of mesenchymal stromal cells (MSCs) for tissue engineering of hyaline cartilage is a topical area of regenerative medicine that has already entered clinical practice. The key stage of this procedure is to create conditions for chondrogenic differentiation of MSCs, increase the synthesis of hyaline cartilage extracellular matrix proteins by these cells and activate their proliferation. The first such works consisted in the indirect modification of cells, namely, in changing the conditions in which they are located, including microfracturing of the subchondral bone and the use of 3D biodegradable scaffolds. The most effective methods for modifying the cell culture of MSCs are protein and physical, which have already been partially introduced into clinical practice. Genetic methods for modifying MSCs, despite their effectiveness, have significant limitations. Techniques have not yet been developed that allow studying the effectiveness of their application even in limited groups of patients. The use of MSC modification methods allows precise regulation of cell culture proliferation, and in combination with the use of a 3D biodegradable scaffold, it allows obtaining a hyaline-like regenerate in the damaged area. This review is devoted to the consideration and comparison of various methods used to modify the cell culture of MSCs for their use in regenerative medicine of cartilage tissue.

Chondrogenic Potential of Dental-Derived Mesenchymal Stromal Cells

The field of tissue engineering has revolutionized the world in organ and tissue regeneration. With the robust research among regenerative medicine experts and researchers, the plausibility of regenerating cartilage has come into the limelight. For cartilage tissue engineering, orthopedic surgeons and orthobiologists use the mesenchymal stromal cells (MSCs) of various origins along with the cytokines, growth factors, and scaffolds. The least utilized MSCs are of dental origin, which are the richest sources of stromal and progenitor cells. There is a paradigm shift towards the utilization of dental source MSCs in chondrogenesis and cartilage regeneration. Dental-derived MSCs possess similar phenotypes and genotypes like other sources of MSCs along with specific markers such as dentin matrix acidic phosphoprotein (DMP) -1, dentin sialophosphoprotein (DSPP), alkaline phosphatase (ALP), osteopontin (OPN), bone sialoprotein (BSP), and STRO-1. Concerning chondrogenicity, there is literature with marginal use of dental-derived MSCs. Various studies provide evidence for in-vitro and in-vivo chondrogenesis by dental-derived MSCs. With such evidence, clinical trials must be taken up to support or refute the evidence for regenerating cartilage tissues by dental-derived MSCs. This article highlights the significance of dental-derived MSCs for cartilage tissue regeneration.

Exploiting Joint-Resident Stem Cells by Exogenous SOX9 for Cartilage Regeneration for Therapy of Osteoarthritis

The lack of effective treatment options for osteoarthritis (OA) is mostly due to the very limited regenerative capacity of articular cartilage. Mesenchymal stem cells (MSCs) have been most extensively explored for cell-based therapy to induce cartilage regeneration for OA. However, current in vitro expanded MSC-based approaches have significant drawbacks. On the other hand, osteoarthritic joints contain chondrocyte progenitors and MSCs in several niches which have the potential yet fail to differentiate into chondrocytes for cartilage regeneration. One of the underlying mechanisms of the failure is that these chondrocyte progenitors and MSCs in OA joints are deficient in the activity of chondrogenic transcription factor SOX9 (SRY-type high-mobility group box-9). Thereby, replenishing with exogenous SOX9 would reactivate the potential of these stem cells to differentiate into chondrocytes. Cell-permeable, super-positively charged SOX9 (scSOX9) protein is able to promote hyaline-like cartilage regeneration by inducing chondrogenic differentiation of bone marrow derived MSCs in vivo. This scSOX9 protein can be administered into osteoarthritic joints by intra-articular injection. This one-step, cell-free supplement of exogenous SOX9 may harness the regenerative potential of the intrinsic MSCs within the joint cavity to stimulate cartilage regeneration in OA.

Potential and recent advances of microcarriers in repairing cartilage defects

Articular cartilage regeneration is one of the challenges faced by orthopedic surgeons. Microcarrier applications have made great advances in cartilage tissue engineering in recent years and enable cost-effective cell expansion, thus providing permissive microenvironments for cells. In addition, microcarriers can be loaded with proteins, factors, and drugs for cartilage regeneration. Some microcarriers also have the advantages of injectability and targeted delivery. The application of microcarriers with these characteristics can overcome the limitations of traditional methods and provide additional advantages. In terms of the transformation potential, microcarriers have not only many advantages, such as providing sufficient and beneficial cells, factors, drugs, and microenvironments for cartilage regeneration, but also many application characteristics; for example, they can be injected to reduce invasiveness, transplanted after microtissue formation to increase efficiency, or combined with other stents to improve mechanical properties. Therefore, this technology has enormous potential for clinical transformation. In this review, we focus on recent advances in microcarriers for cartilage regeneration. We compare the characteristics of microcarriers with other methods for repairing cartilage defects, provide an overview of the advantages of microcarriers, discuss the potential of microcarrier systems, and present an outlook for future development.

Translational potential of this article

We reviewed the advantages and recent advances of microcarriers for cartilage regeneration. This review could give many scholars a better understanding of microcarriers, which can provide doctors with potential methods for treating patients with cartilage injure.

Zinc chloride affects chondrogenesis via VEGF signaling

Insulin mimetics, including zinc containing compounds, have previously been shown to influence chondrogenesis as it relates to healing of fractures in various preclinical models. However, the mechanism by which these compounds drive chondrogenic differentiation is yet undefined. Here, via next-generation sequencing (NGS) and in vitro functional validation, we show that Zinc Chloride (ZnCl₂) induces expression of both chondrogenic genes (Sox9, Runx1, collagen) as well as genes associated with VEGF-mediated signal transduction, including VEGF receptors 1 and 2 and their ligands; VEGF-A and VEGF-B. Noticeably, although insulin was able to also induce expression of these pro-angiogenic and pro-chondrogenic genes, the impact of insulin on expression of VEGF receptor and ligand genes was marginal when compared to that of ZnCl_2. Furthermore, while the VEGFR antagonist, Axitinib, was able to attenuate the pro-chondrogenic effects of both insulin and ZnCl₂; a reduction in gene and protein expression was most profoundly observed when the antagonist was applied to cells treated with ZnCl_2. Taken together, these data suggest an important role for the VEGF-mediated signal transduction pathways in the positive effects observed when applying zinc-based compounds as adjuvants for chondrogenesis-mediated fracture healing. In this regard, further mechanistic evaluation of ZnCl₂ and other zinc-containing insulin mimetics may support rational design of therapies targeted for disease indications associated with impaired fracture healing.

Long-term durable repaired cartilage induced by SOX9 in situ with bone marrow-derived mesenchymal stem cells

Background: Microfracture is a common procedure for cartilage repair, but it often produces inferior fibrocartilage. We previously reported that a super positively charged SOX9 (scSOX9) promoted hyaline-like cartilage regeneration by inducing bone marrow derived mesenchymal stem cell differentiation into chondrocytes in vivo. Here we examined the long-term efficacy of cartilage repair induced by microfracture with scSOX9 by assessing the biomechanical property of the repaired cartilage. Methods: A cartilage defect was created at the right femoral trochlear groove in New Zealand female rabbits and microfracture was performed. The scSOX9 protein was administered at the site of microfracture incorporated in a collagen membrane. Results: At 12 and 24 weeks, scSOX9 treatment induced hyaline-like cartilage while collagen-membrane alone induced fibrocartilage and mutant scSOX9-A76E poorly induced cartilage repair. The cartilage matrix in scSOX9-treated group showed highly enriched proteoglycan content. Consistent with the histological feature and the thickness of the repaired cartilage, the mechanical property of scSOX9-induced cartilage was also similar to that of normal cartilage. Conclusion: This long-term in vivo study demonstrated that in combination with microfracture, scSOX9 was able to induce reparative tissue with features of hyaline cartilage which was durable in long-term. This technology has the potential to translate into clinical use for cartilage repair to prevent progression to osteoarthritis.

Comparative matched-pair cohort analysis of the short-term clinical outcomes of mesenchymal stem cells versus hyaluronic acid treatments through intra-articular injections for knee osteoarthritis

Purpose

Intra-articular injection of hyaluronic acid (HA) has shown promises in reducing pain and improving physical function in knee osteoarthritis (OA). Recently, cell-based therapies using mesenchymal stem cells (MSCs) have emerged as potential treatments. However, few studies have compared the treatment outcomes between MSCs and HA. This study aimed to compare the clinical and radiological outcomes of intra-articular injections of MSCs versus HA in patients with knee OA.

Methods

A cohort of 209 patients with knee OA were retrospectively screened for those who underwent intra-articular injections using MSCs or HA. Thirty MSC-treated patients (MSC group) were pair-matched with thirty HA-treated patients (HA group) based on gender and age. Clinical outcomes were evaluated using the visual analog scale (VAS), International Knee Documentation Committee (IKDC) rating system, and Lysholm scoring system. Radiological evaluation was assessed using the Kellgren-Lawrence (K-L) grading system.

Results

MSC treatment yielded consistent significant improvements in VAS, IKDC and Lysholm scores. In the HA group, VAS scores significantly decreased at 1 month, slightly increased at 3 months, and increased significantly from 3 months to 1 year after injection. The IKDC and Lysholm scores improved significantly until 3 months, but gradually worsened thereafter. Significantly greater improvements in VAS (P = 0.041), IKDC (P = 0.014), and Lysholm (P = 0.020) scores were observed in the MSC group compared to those in the HA group at 1-year post-treatment. The K-L grade worsened in a few patients, especially those in the HA group, albeit no significant difference.

Conclusions

MSC group showed better VAS, IKDC, and Lysholm scores at 1-year post-treatment, compared to the HA group, although earlier clinical improvements were superior in the HA group for the initial 3 months.

Level of Evidence

Therapeutic study, Level III.

The combination of microfracture with induction of Wnt / β- Catenin pathway, leads to enhanced cartilage regeneration

INTRODUCTION

Microfracture does not lead to complete healing of full-thickness cartilage defects. The aim of this study was to evaluate the effect of modifying Wnt/β-catenin signaling following microfracture, on the restoration of a full-thickness cartilage defect in a rabbit model. The modification of the canonical Wnt pathway was achieved through per os administration of lithium carbonate, which is an intracellular inhibitor of glycogen synthase kinase 3-β (Gsk3-β) and therefore induces Wnt/β-catenin signaling.

MATERIALS AND METHODS

Full-thickness cartilage defects of 4 mm in diameter were created in the patellar groove of the right femurs of 18 male New Zealand white rabbits. The rabbits were divided into three groups of six (n = 6) based on post-surgery treatment differences, as follows: microfracture only (group 1), microfracture plus lithium carbonate 7 mM in the drinking water for 1 week (group 2), microfracture plus lithium carbonate 7 mM in the drinking water for 4 weeks (group 3). All animals were sacrificed 9 weeks after surgery. The outcome was assessed histologically, by using the International Cartilage Repair Society (ICRS) visual histological scale. Immunohistochemistry for type II collagen was also conducted.

RESULTS

Statistical analysis of the histological ICRS scores showed that group 3 was significantly superior to group 1 in four out of six ICRS categories, while group 2 was superior to 1 in only two out of six.

CONCLUSION

The combination of microfracture and systematic administration of lithium carbonate 7 mM for 4 weeks shows statistically significant superiority in four out of six ICRS categories compared with microfracture only for the treatment of full-thickness cartilage defects in a rabbit experimental model.

Synovium-Derived Mesenchymal Stem Cell Transplantation in Cartilage Regeneration: A PRISMA Review of in vivo Studies

Articular cartilage damaged through trauma or disease has a limited ability to repair. Untreated, focal lesions progress to generalized changes including osteoarthritis. Musculoskeletal disorders including osteoarthritis are the most significant contributor to disability globally. There is increasing interest in the use of mesenchymal stem cells (MSCs) for the treatment of focal chondral lesions. There is some evidence to suggest that the tissue type from which MSCs are harvested play a role in determining their ability to regenerate cartilage in vitro and in vivo. In humans, MSCs derived from synovial tissue may have superior chondrogenic potential. We carried out a systematic literature review on the effectiveness of synovium-derived MSCs (sMSCs) in cartilage regeneration in in vivo studies in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Twenty studies were included in our review; four examined the use of human sMSCs and 16 were conducted using sMSCs harvested from animals. Most studies reported successful cartilage repair with sMSC transplantation despite the variability of animals, cell harvesting techniques, methods of delivery, and outcome measures. We conclude that sMSC transplantation holds promise as a treatment option for focal cartilage defects. We believe that defining the cell population being used, establishing standardized methods for MSC delivery, and the use of objective outcome measures should enable future high quality studies such as randomized controlled clinical trials to provide the evidence needed to manage chondral lesions optimally.

Adjuvant therapies for the enhancement of microfracture technique in cartilage repair

The classic technique of microfracture does not promote hyaline cartilage restoration. Subchondral bone perforations lead to the formation of a clot containing pluripotent progenitor cells and finally the cartilage defect is filled by fibrocartilage tissue. Researchers have focused on enhancing the quality of the newly formed tissue in cartilage defects after microfracture arthroscopic surgery. Adjuvant treatments are categorized in four main groups: scaffolds, pharmaceutical agents, growth factors and combinations of the aforementioned. Several experimental studies utilize pharmaceutical or biological agents in combination with microfracture, to improve the quality of the regenerated cartilage. The mechanism of action of the agents used is either to exert a chondroprotective effect on the newly formed fibrocartilage tissue, or to induce the recruitment of mesenchymal stem cells towards chondrogenesis instead of osteogenesis during microfracture repair. Additionally, scaffolds have been used for both release of the biological agents and mechanical support of the newly formed blood clot. This review highlights current data regarding the combination of microfracture technique with adjuvant treatments in order to ameliorate the final outcome.

Articular cartilage regeneration and tissue engineering models: a systematic review

INTRODUCTION

Cartilage regeneration and restoration is a major topic in orthopedic research as cartilaginous degeneration and damage is associated with osteoarthritis and joint destruction. This systematic review aims to summarize current research strategies in cartilage regeneration research.

MATERIALS AND METHODS

A Pubmed search for models investigating single-site cartilage defects as well as chondrogenesis was conducted and articles were evaluated for content by title and abstract. Finally, only manuscripts were included, which report new models or approaches of cartilage regeneration.

RESULTS

The search resulted in 2217 studies, 200 of which were eligible for inclusion in this review. The identified manuscripts consisted of a large spectrum of research approaches spanning from cell culture to tissue engineering and transplantation as well as sophisticated computational modeling.

CONCLUSIONS

In the past three decades, knowledge about articular cartilage and its defects has multiplied in clinical and experimental settings and the respective body of research literature has grown significantly. However, current strategies for articular cartilage repair have not yet succeeded to replicate the structure and function of innate articular cartilage, which makes it even more important to understand the current strategies and their impact. Therefore, the purpose of this review was to globally summarize experimental strategies investigating cartilage regeneration in vitro as well as in vivo. This will allow for better referencing when designing new models or strategies and potentially improve research translation from bench to bedside.

Umbilical Cord-Derived Mesenchymal Stromal Cells (MSCs) for Knee Osteoarthritis: Repeated MSC Dosing Is Superior to a Single MSC Dose and to Hyaluronic Acid in a Controlled Randomized Phase I/II Trial

Knee osteoarthritis (OA) is a leading cause of pain and disability. Although conventional treatments show modest benefits, pilot and phase I/II trials with bone marrow (BM) and adipose‐derived (AD) mesenchymal stromal cells (MSCs) point to the feasibility, safety, and occurrence of clinical and structural improvement in focal or diffuse disease. This study aimed to assess the safety and efficacy of the intra‐articular injection of single or repeated umbilical cord‐derived (UC) MSCs in knee OA. UC‐MSCs were cultured in an International Organization for Standardization 9001:2015 certified Good Manufacturing Practice‐type Laboratory. Patients with symptomatic knee OA were randomized to receive hyaluronic acid at baseline and 6 months (HA, n = 8), single‐dose (20 × 10⁶) UC‐MSC at baseline (MSC‐1, n = 9), or repeated UC‐MSC doses at baseline and 6 months (20 × 10⁶ × 2; MSC‐2, n = 9). Clinical scores and magnetic resonance images (MRIs) were assessed throughout the 12 months follow‐up. No severe adverse events were reported. Only MSC‐treated patients experienced significant pain and function improvements from baseline (p = .001). At 12 months, Western Ontario and Mc Master Universities Arthritis Index (WOMAC‐A; pain subscale) reached significantly lower levels of pain in the MSC‐2‐treated group (1.1 ± 1.3) as compared with the HA group (4.3 ± 3.5; p = .04). Pain Visual Analog scale was significantly lower in the MSC‐2 group versus the HA group (2.4 ± 2.1 vs. 22.1 ± 9.8, p = .03) at 12 months. For total WOMAC, MSC‐2 had lower scores than HA at 12 months (4.2 ± 3.9 vs. 15.2 ± 11, p = .05). No differences in MRI scores were detected. In a phase I/II trial (NCT02580695), repeated UC‐MSC treatment is safe and superior to active comparator in knee OA at 1‐year follow‐up. stem cells translational medicine2019;8:215&224