Extracellular Protease Inhibition Alters the Phenotype of Chondrogenically Differentiating Human Mesenchymal Stem Cells (MSCs) in 3D Collagen Microspheres

Mesenchymal Stem/Stromal Cells Microencapsulation for Cell Therapy

Cell microencapsulation is one of the most studied strategies to overcome the challenges associated with the implementation of mesenchymal stem/stromal cells (MSCs) in vivo. This approach isolates/shields donor MSCs from the host immune system using a semipermeable membrane that allows for the diffusion of gases, nutrients, and therapeutics, but not host immune cells. As a result, microencapsulated MSCs survive and engraft better after infusion, and they can be delivered specifically to the targeted site. Additionally, microencapsulation enables the co-culture of MSCs with different types of cells in a three-dimensional (3D) environment, allowing for better cellular interaction. Alginate, collagen, and cellulose are the most popular materials, and air jet extrusion, microfluidics, and emulsion are the most used techniques for MSC cell encapsulation in the literature. These materials and techniques differ in the size range of the resultant microcapsules and their compatibility with the applied materials. This review discusses various materials and techniques used for the microencapsulation of MSCs. We also shed light on the recent findings in this field, the advantages and drawbacks of using encapsulated MSCs, and the in vivo translation of the microencapsulated MSCs in cell therapy.

Innovative bioinks for 3D bioprinting: Exploring technological potential and regulatory challenges

The field of three dimensional (3D) bioprinting has witnessed significant advancements, with bioinks playing a crucial role in enabling the fabrication of complex tissue constructs. This review explores the innovative bioinks that are currently shaping the future of 3D bioprinting, focusing on their composition, functionality, and potential for tissue engineering, drug delivery, and regenerative medicine. The development of bioinks, incorporating natural and synthetic materials, offers unprecedented opportunities for personalized medicine. However, the rapid technological progress raises regulatory challenges regarding safety, standardization, and long-term biocompatibility. This paper addresses these challenges, examining the current regulatory frameworks and the need for updated guidelines to ensure patient safety and product efficacy. By highlighting both the technological potential and regulatory hurdles, this review offers a comprehensive overview of the future landscape of bioinks in bioprinting, emphasizing the necessity for cross-disciplinary collaboration between scientists, clinicians, and regulatory bodies to achieve successful clinical applications.

[Advantages and prospects of cell derived decellularized extracellular matrix as tissue engineering scaffolds]

OBJECTIVE

To review the application of cell derived decellularized extracellular matrix (CDM) in tissue engineering.

METHODS

The literature related to the application of CDM in tissue engineering was extensively reviewed and analyzed.

RESULTS

CDM is a mixture of cells and their secretory products obtained by culturing cells in vitro for a period of time, and then the mixture is treated by decellularization. Compared with tissue derived decellularized extracellular matrix (TDM), CDM can screen and utilize pathogen-free autologous cells, effectively avoiding the possible shortcomings of TDM, such as immune response and limited sources. In addition, by selecting the cell source, controlling the culture conditions, and selecting the template scaffold, the composition, structure, and mechanical properties of the scaffold can be controlled to obtain the desired scaffold. CDM retains the components and microstructure of extracellular matrix and has excellent biological functions, so it has become the focus of tissue engineering scaffolds.

CONCLUSION

CDM is superior in the field of tissue engineering because of its outstanding adjustability, safety, and high bioactivity. With the continuous progress of technology, CDM stents suitable for clinical use are expected to continue to emerge.

3D Bioprinting of Biomimetic Alginate/Gelatin/Chondroitin Sulfate Hydrogel Nanocomposites for Intrinsically Chondrogenic Differentiation of Human Mesenchymal Stem Cells

3D-printed hydrogel scaffolds biomimicking the extracellular matrix (ECM) are key in cartilage tissue engineering as they can enhance the chondrogenic differentiation of mesenchymal stem cells (MSCs) through the presence of active nanoparticles such as graphene oxide (GO). Here, biomimetic hydrogels were developed by cross-linking alginate, gelatin, and chondroitin sulfate biopolymers in the presence of GO as a bioactive filler, with excellent processability for developing bioactive 3D printed scaffolds and for the bioprinting process. A novel bioink based on our hydrogel with embedded human MSCs presented a cell survival rate near 100% after the 3D bioprinting process. The effects of processing and filler concentration on cell differentiation were further quantitatively evaluated. The nanocomposited hydrogels render high MSC proliferation and viability, exhibiting intrinsic chondroinductive capacity without any exogenous factor when used to print scaffolds or bioprint constructs. The bioactivity depended on the GO concentration, with the best performance at 0.1 mg mL-1. These results were explained by the rational combination of the three biopolymers, with GO nanoparticles having carboxylate and sulfate groups in their structures, therefore, biomimicking the highly negatively charged ECM of cartilage. The bioactivity of this biomaterial and its good processability for 3D printing scaffolds and 3D bioprinting techniques open up a new approach to developing novel biomimetic materials for cartilage repair.

Cell-Derived Matrix: Production, Decellularization, and Application of Wound Repair

Chronic nonhealing wounds significantly reduce patients' quality of life and are a major burden on healthcare systems. Over the past few decades, tissue engineering materials have emerged as a viable option for wound healing, with cell-derived extracellular matrix (CDM) showing remarkable results. The CDM's compatibility and resemblance to the natural tissue microenvironment confer distinct advantages to tissue-engineered scaffolds in wound repair. This review summarizes the current processes for CDM preparation, various cell decellularization protocols, and common characterization methods. Furthermore, it discusses the applications of CDM in wound healing, including skin defect and wound repair, angiogenesis, and engineered vessels, and offers perspectives on future developments.

Differentiation of Equine Mesenchymal Stem Cells into Cells of Osteochondral Lineage: Potential for Osteochondral Tissue Engineering

Damage to the hyaline cartilage of the joint surface and osteochondral fractures are key factors leading to the development of osteoarthritis in racehorses, representing a significant cause of racehorse retirement. To tissue-engineer an osteochondral unit that is suitable for joint repair, incorporation of a zone of calcified cartilage should be considered so as to mimic its in vivo counterpart. To date, equine mesenchymal stem cells (eMSCs) have been reported to have multilineage differentiation potential. Yet the generation of a zone of calcified cartilage using eMSCs has not been reported. This work is an initial attempt to generate a zone of calcified cartilage using eMSCs as the single source of cells and collagen as the scaffolding material. Main advantages of using eMSCs over equine deep zone chondrocytes for the generation of a zone of calcified cartilage include no donor site morbidity and their ease of expansion in culture. Initially, we fabricated cartilage-like tissues and bone-like tissues in vitro by differentiating eMSCs towards chondrogenic and osteogenic lineages for 21 days, respectively. We then aggregated the cartilage-like and bone-like tissues together with a layer of undifferentiated eMSCs-collagen gel in between to generate a 3-layer osteochondral unit. A zone of calcified cartilage was found between the cartilage-like and bone-like layers after a 14-day culture in chondrogenic differentiation medium. These results provide a solution towards tissue engineering of equine osteochondral units with interfacial zone without using chondrocytes harvested from the deep zone of healthy articular cartilage, and contribute to the future development of osteochondral tissue engineering strategies for human cartilage injuries in the long run.

Towards Biomanufacturing of Cell-Derived Matrices

Cell-derived matrices (CDM) are the decellularised extracellular matrices (ECM) of tissues obtained by the laboratory culture process. CDM is developed to mimic, to a certain extent, the properties of the needed natural tissue and thus to obviate the use of animals. The composition of CDM can be tailored for intended applications by carefully optimising the cell sources, culturing conditions and decellularising methods. This unique advantage has inspired the increasing use of CDM for biomedical research, ranging from stem cell niches to disease modelling and regenerative medicine. However, while much effort is spent on extracting different types of CDM and exploring their utilisation, little is spent on the scale-up aspect of CDM production. The ability to scale up CDM production is essential, as the materials are due for clinical trials and regulatory approval, and in fact, this ability to scale up should be an important factor from the early stages. In this review, we first introduce the current CDM production and characterisation methods. We then describe the existing scale-up technologies for cell culture and highlight the key considerations in scaling-up CDM manufacturing. Finally, we discuss the considerations and challenges faced while converting a laboratory protocol into a full industrial process. Scaling-up CDM manufacturing is a challenging task since it may be hindered by technologies that are not yet available. The early identification of these gaps will not only quicken CDM based product development but also help drive the advancement in scale-up cell culture and ECM extraction.

ChondroGELesis: Hydrogels to harness the chondrogenic potential of stem cells

The extracellular matrix is a highly complex microenvironment, whose various components converge to regulate cell fate. Hydrogels, as water-swollen polymer networks composed by synthetic or natural materials, are ideal candidates to create biologically active substrates that mimic these matrices and target cell behaviour for a desired tissue engineering application. Indeed, the ability to tune their mechanical, structural, and biochemical properties provides a framework to recapitulate native tissues. This review explores how hydrogels have been engineered to harness the chondrogenic response of stem cells for the repair of damaged cartilage tissue. The signalling processes involved in hydrogel-driven chondrogenesis are also discussed, identifying critical pathways that should be taken into account during hydrogel design.

Cell-derived matrices (CDM)-Methods, challenges and applications

Extracellular matrix (ECM) provides both physical support and bioactive signals such as growth factors and cytokines to cells at their microenvironment or niche. Engineering the matrix niche becomes an important approach to study or manipulate cellular fate. This work presents an overview on the reconstitution of the ECM niche through a wide range of approaches ranging from coating culture dish with ECM molecules to decellularization of native tissues. In particular, we focused on reconstituting the complex ECM niche through cell-derived matrix (CDM) by reviewing the methodological approaches used in our group to derive ECM from mature cells such as chondrocytes and nucleus pulposus cells (NPCs), undifferentiated stem cells such as mesenchymal stem cells (MSCs), as well as MSCs undergoing chondrogenic and osteogenic differentiation, in 2D or 3D models. Specific attention has also been given to key factors that should be considered in various applications and challenges in relation to the CDM. Last but not the least, a few future perspectives and their significance have been proposed.

Clinical efficacy and safety of mesenchymal stem cell transplantation for osteoarthritis treatment: A meta-analysis

Purpose

The aim of this study was to evaluate the therapeutic efficacy and safety of mesenchymal stem cells (MSCs) for the treatment of patients with knee osteoarthritis (OA).

Materials

We performed a meta-analysis of relevant published clinical studies. An electronic search was conducted for randomized controlled trials (RCTs) of MSC-based therapy in knee OA. The visual analogue scale (VAS), International Knee Documentation Committee (IKDC) form, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lequesne algofunctional indices (Lequesne), Lysholm knee scale (Lysholm), Tegner activity scale (Tegner) and adverse events (AEs) were evaluated.

Results

Eleven eligible trials with 582 knee OA patients were included in the present meta-analysis. We demonstrated that MSC treatment could significantly decrease VAS and increase IKDC scoresafter a 24-month follow-up compared with controls (P<0.05). MSC therapy also showed significant decreases in WOMAC and Lequesne scores after the 12-month follow-up (P<0.01). Analysis of Lysholm (24-month) and Tegner (12- and 24-month) scores also demonstrated favorable results for MSC treatment (P<0.05).

Conclusion

Overall, MSC transplantation treatment was shown to be safe and has great potential as an efficacious clinical therapy for patients with knee OA.