In vitro chondrogenic commitment of human Wharton's jelly stem cells by co-culture with human articular chondrocytes

Cross Talk Between Cells and the Current Bioceramics in Bone Regeneration: A Comprehensive Review

The conventional approach for addressing bone defects and stubborn non-unions typically involves the use of autogenous bone grafts. Nevertheless, obtaining these grafts can be challenging, and the procedure can lead to significant morbidity. Three primary treatment strategies for managing bone defects and non-unions prove resistant to conventional treatments: synthetic bone graft substitutes (BGS), a combination of BGS with bioactive molecules, and the use of BGS in conjunction with stem cells. In the realm of synthetic BGS, a multitude of biomaterials have emerged for creating scaffolds in bone tissue engineering (TE). These materials encompass biometals like titanium, iron, magnesium, and zinc, as well as bioceramics such as hydroxyapatite (HA) and tricalcium phosphate (TCP). Bone TE scaffolds serve as temporary implants, fostering tissue ingrowth and the regeneration of new bone. They are meticulously designed to enhance bone healing by optimizing geometric, mechanical, and biological properties. These scaffolds undergo continual remodeling facilitated by bone cells like osteoblasts and osteoclasts. Through various signaling pathways, stem cells and bone cells work together to regulate bone regeneration when a portion of bone is damaged or deformed. By targeting signaling pathways, bone TE can improve bone defects through effective therapies. This review provided insights into the interplay between cells and the current state of bioceramics in the context of bone regeneration.

Transplantation of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Improves Cartilage Repair in a Rabbit Model

The aim of this study was to investigate the therapeutic efficacy and safety of transplanting human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) in the treatment of cartilage injury. First, the articular cartilage defect model in rabbits was constructed. Then, the identified hUCB-MSCs and rabbit bone marrow stem cells (rBM-MSCs) were transplanted into the bone defect, respectively, and the cartilage repair effect was observed by hematoxylin-eosin (HE) staining and immunohistochemistry. Besides, the glycosaminoglycan (GAG) content and biomechanics of the restoration area were also evaluated. In our study, hUCB-MSCs and rBM-MSCs exhibited typical MSC characteristics, with positive expressions of CD73, CD105, and CD90 and negative for CD45, CD34, CD14, and HLA-DR. After the transplantation of hUCB-MSCs and rBM-MSCs, the overall quality of cartilage tissue was significantly improved, and the recipients did not show significant side effects in general. However, the expression of matrix metalloproteinase-13 (MMP-13) in the de novo tissues of the hUCB-MSCs and rBM-MSCs groups was both increased, indicating that the novel tissues may have some potential osteoarthritic changes. In conclusion, our results suggest the therapeutic effect of hUCB-MSCs transplantation in cartilage regeneration, providing a promising future in the clinical treatment of cartilage injury.

Human Stem Cell Based Tissue Engineering for In Vivo Cartilage Repair: A Systematic Review

Pure chondral defects represent the most clinically significant articular cartilage injuries. To inform the development of clinically suitable tissue-engineering strategies for chondral repair using cells from a human patient, the combination of human stem cells (HSCs), biomaterial scaffolds, and growth factors has been widely harnessed in preclinical animal models. Due to the large heterogeneity in study designs and outcome reporting in such studies, we aimed to systematically review literature pertaining to HSC based tissue engineering strategies in animal models of chondral repair such that trends may be identified and the utility of HSCs in chondral repair can be elucidated. An extensive search strategy was carried out through PubMed, MEDLINE, and EMBASE databases to identify relevant studies. Initially the title and abstract of 787 studies were screened after which inclusion and exclusion criteria sorted 56 studies for full-text evaluation. Following full text review, a final number of 22 articles were included. Out of 22 included studies, 16 used scaffold implantation, 2 used cell pellet implantation, and 4 used intra-articular injection to administer HSCs to the region of chondral defects. HSC-containing implants outperformed scaffold-only or untreated control groups in both large and small animals for chondral regeneration. Umbilical cord mesenchymal stem cells and hyaluronic acid-containing scaffolds emerged as popular stem cell and scaffold choices, respectively. However, the short analysis timepoints post cell implantation was a key limitation in many studies. This review highlights the versatility of HSCs in achieving chondral regeneration in vivo and the enhancement of chondral repair through the selection of appropriate three-dimensional scaffolds and growth factors which are essential to support cell growth, attachment, migration, and extracellular matrix synthesis. Considerable heterogeneity exists in outcome reporting, and only one article reported biomechanical evaluation of neocartilage. Standardized outcome reporting systems that include comprehensive biomechanical testing protocols should be utilized in future in vivo studies of cartilage tissue engineering as the biomechanical quality of neocartilage is of great functional significance.

Enhanced chondrogenesis in a coculture system with genetically manipulated dedifferentiated chondrocytes and ATDC5 cells

Articular cartilage repair after injury is a great challenge worldwide due to its nerveless and avascular features. Tissue engineering is proposed as a promising alternative for cartilage regeneration. In this study, an adenoviral vector carrying the transforming growth factor-β3 (TGF-β3) gene was constructed and introduced into dedifferentiated chondrocytes, which were then cocultured with ATDC5 cells in an alginate hydrogel system. The results showed that the experimental groups exhibited better cell viability and higher levels of cartilage-related genes than the control groups. In this coculture system, the chondrogenic differentiation of ATDC5 cells was effectively induced by TGF-β3 and other latent cytokines that were produced by the transfected chondrocytes. Thus, this method can avoid the degradation of exogenous TGF-β3, and it can protect ATDC5 cells during virus transfection to maintain cell viability and chondrogenic differentiation capability. Taken together, this study provides fresh insights for applying this genetically manipulated coculture system to cartilage repair in the future.

Biosynthesis, characterization and evaluation of the supportive properties and biocompatibility of DBM nanoparticles on a tissue-engineered nerve conduit from decellularized sciatic nerve

In this study, we examined the supporting effects of nano-demineralized bone matrix on the cultivation of Wharton's jelly stem cells on acellularized nerve scaffold. Demineralized bone matrix nanoparticles were prepared and characterized by several experiments. Decellularized sciatic nerve scaffolds were prepared and their efficiency was evaluated using histological stainings and biomechanical testing. Results of histological staining indicated that the integrity of the extra cellular matrix components was preserved. Also, the growth and viability of WJSCs on the scaffolds were significantly higher in DBM nanoparticle groups. We conclude that supportive properties of nano-DBM groups showed better cell viability and a suitable microenvironment for proliferation, retention, and adhesion of cells compared with other groups.

Co-culture of hWJMSCs and pACs in double biomimetic ACECM oriented scaffold enhances mechanical properties and accelerates articular cartilage regeneration in a caprine model

Background

The dedifferentiation of chondrocytes and the unstable chondrogenic differentiation status of pluripotent mesenchymal stem cells (MSCs) are immense issues in cell-based articular cartilage repair and regenerative strategies. Here, to improve the cartilage characteristics of seed cells, a double biomimetic acellular cartilage extracellular matrix (ACECM)-oriented scaffold was used to mimic the cartilage microenvironment for human umbilical cord Wharton’s jelly-derived MSCs (hWJMSCs) and primary cartilage cells (pACs) to regenerate hyaline cartilage.

Methods

A double biomimetic ACECM-oriented scaffold was created from the cartilage extracellular matrix of pig articular cartilage using pulverization decellularization freeze-drying procedures. hWJMSCs and pACs were co-cultured at ratios of 50:50 (co-culture group, ACCC), 0:100 (ACAC group) and 100:0 (ACWJ group) in the ACECM-oriented scaffold, and the co-culture system was implanted in a caprine model for 6 months or 9 months to repair full-thickness articular cartilage defects. The control groups, which had no cells, comprised the blank control (BC) group and the ACECM-oriented scaffold (AC) group. Gross morphology and magnetic resonance imaging (MRI) as well as histological and biomechanical evaluations were used to characterize the cartilage of the repair area.

Results

Relative to the control groups, both the gross morphology and histological staining results demonstrated that the neotissue of the ACCC group was more similar to native cartilage and better integrated with the surrounding tissue. Measurements of glycosaminoglycan content and Young’s modulus showed that the repair areas had more abundant cartilage-specific content and significantly higher mechanical strength in the ACCC group than in the control groups, especially at 9 months. On MRI, the T2-weighted signal of the repair area was homogeneous, and the oedema signal disappeared almost completely in the ACCC group at 9 months. HLA-ABC immunofluorescence staining demonstrated that hWJMSCs participated in the repair and regeneration of articular cartilage and escaped surveillance and clearance by the caprine immune system.

Conclusion

The structure and components of double biomimetic ACECM-oriented scaffolds provided a cartilage-like microenvironment for co-cultured seed cells and enhanced the biomechanics and compositions of neotissue. This co-culture system has the potential to overcome the dedifferentiation of passage chondrocytes and the unstable chondrogenic differentiation status of MSCs.

Expanded Differentiation Capability of Human Wharton's Jelly Stem Cells Toward Pluripotency: A Systematic Review

Human Wharton's jelly stem cells (HWJSC) can be efficiently isolated from the umbilical cord, and numerous reports have demonstrated that these cells can differentiate into several cell lineages. This fact, coupled with the high proliferation potential of HWJSC, makes them a promising source of stem cells for use in tissue engineering and regenerative medicine. However, their real potentiality has not been established to date. In the present study, we carried out a systematic review to determine the multilineage differentiation potential of HWJSC. After a systematic literature search, we selected 32 publications focused on the differentiation potential of these cells. Analysis of these studies showed that HWJSC display expanded differentiation potential toward some cell types corresponding to all three embryonic cell layers (ectodermal, mesodermal, and endodermal), which is consistent with their constitutive expression of key pluripotency markers such as OCT4, SOX2, and NANOG, and the embryonic marker SSEA4. We conclude that HWJSC can be considered cells in an intermediate state between multipotentiality and pluripotentiality, since their proliferation capability is not unlimited and differentiation to all cell types has not been demonstrated thus far. These findings support the clinical use of HWJSC for the treatment of diseases affecting not only mesoderm-type tissues but also other cell lineages. Impact statement Human Wharton's jelly stem cells (HWJSC) are mesenchymal stem cells that are easy to isolate and handle, and that readily proliferate. Their wide range of differentiation capabilities supports the view that these cells can be considered pluripotent. Accordingly, HWJSC are one of the most promising cell sources for clinical applications in advanced therapies.

Coculture of hWJMSCs and pACs in Oriented Scaffold Enhances Hyaline Cartilage Regeneration In Vitro

Seed cells of articular cartilage tissue engineering face many obstacles in their application because of the dedifferentiation of chondrocytes or unstable chondrogenic differentiation status of pluripotent stem cells. To overcome mentioned dilemmas, a simulation of the articular cartilage microenvironment was constructed by primary articular cartilage cells (pACs) and acellular cartilage extracellular matrix- (ACECM-) oriented scaffold cocultured with human umbilical cord Wharton's jelly-derived mesenchymal stem cells (hWJMSCs) in vitro. The coculture groups showed more affluent cartilage special matrix ingredients including collagen II and aggrecan based on the results of histological staining and western blotting and cut down as many pACs as possible. The RT-PCR and cell viability experiments also demonstrated that hWJMSCs were successfully induced to differentiate into chondrocytes when cultured in the simulated cartilage microenvironment, as confirmed by the significant upregulation of collagen II and aggrecan, while the cell proliferation activity of pACs was significantly improved by cell-cell interactions. Therefore, compared with monoculture and chondrogenic induction of inducers, coculture providing a simulated native articular microenvironment was a potential and temperate way to regulate the biological behaviors of pACs and hWJMSCs to regenerate the hyaline articular cartilage.

Progress of co-culture systems in cartilage regeneration

INTRODUCTION

Cartilage tissue engineering has rapidly developed in recent decades, exhibiting promising potential to regenerate and repair cartilage. However, the origin of a large amount of a suitable seed cell source is the major bottleneck for the further clinical application of cartilage tissue engineering. The use of a monoculture of passaged chondrocytes or mesenchymal stem cells results in undesired outcomes, such as fibrocartilage formation and hypertrophy. In the last two decades, co-cultures of chondrocytes and a variety of mesenchymal stem cells have been intensively investigated in vitro and in vivo, shedding light on the perspective of co-culture in cartilage tissue engineering.

AREAS COVERED

We summarize the recent literature on the application of heterologous cell co-culture systems in cartilage tissue engineering and compare the differences between direct and indirect co-culture systems as well as discuss the underlying mechanisms.

EXPERT OPINION

Co-culture system is proven to address many issues encountered by monocultures in cartilage tissue engineering, including reducing the number of chondrocytes needed and alleviating the dedifferentiation of chondrocytes. With the further development and knowledge of biomaterials, cartilage tissue engineering that combines the co-culture system and advanced biomaterials is expected to solve the difficult problem regarding the regeneration of functional cartilage.

Human umbilical cord Wharton's jelly mesenchymal stem cells combined with an acellular cartilage extracellular matrix scaffold improve cartilage repair compared with microfracture in a caprine model

OBJECTIVE

As a novel and promising seed cell, human umbilical cord Wharton's jelly mesenchymal stem cells (hWJMSCs) are widely applied in tissue engineering. However, whether hWJMSCs can better repair and regenerate the articular cartilage in big animals than microfracture (MF, a predominant clinical treatment strategy for damaged cartilage) is unclear. Evaluation of the validity, and safety of hWJMSCs in a caprine model with a full-thickness femoral condyle articular cartilage defect, compared with MF is required.

METHODS

After cultivation and identification, hWJMSCs were seeded in an acellular cartilage extracellular matrix (ACECM)-oriented scaffold to construct cell-scaffold complex. Six goats with full-thickness femoral condyle articular cartilage defects were randomized to MF (microfracture group, MFG) and cell-scaffold complexes (experimental group, EG). At 2 and 4 weeks, joint fluid was used to assess immuno-inflammatory responses. At 6 and 9 months, all goats were euthanized for assessment of morphology, and magnetic resonance imaging (MRI), histology staining, and evaluation of the elasticity modulus and glycosaminoglycan (GAG) contents of the repaired regions.

RESULTS

There were no significant differences between the two groups in immuno-inflammatory parameters. MRI demonstrated higher-quality cartilage and complete subchondral bone at defect sites in the EG at 9 months. Histological staining showed that extracellular cartilage, cartilage lacuna and collagen type II levels were higher in the EG compared to the MFG, while the EG exhibited a higher elasticity modulus.

CONCLUSIONS

The hWJMSCs-ACECM scaffold complex achieved better quality repair and regeneration of hyaline cartilage without cartilage-inducing factor, while retaining the structure and functional integrity of the subchondral bone, compared with MF.