Increased Expression of Sox9 during Balance of BMSCs/Chondrocyte Bricks in Platelet-Rich Plasma Promotes Construction of a Stable 3-D Chondrogenesis Microenvironment for BMSCs

Hydrogel Based on Chitosan/Gelatin/Poly(Vinyl Alcohol) for In Vitro Human Auricular Chondrocyte Culture

Three-dimensional (3D) hydrogels provide tissue-like complexities and allow for the spatial orientation of cells, leading to more realistic cellular responses in pathophysiological environments. There is a growing interest in developing multifunctional hydrogels using ternary mixtures for biomedical applications. This study examined the biocompatibility and suitability of human auricular chondrocytes from microtia cultured onto steam-sterilized 3D Chitosan/Gelatin/Poly(Vinyl Alcohol) (CS/Gel/PVA) hydrogels as scaffolds for tissue engineering applications. Hydrogels were prepared in a polymer ratio (1:1:1) through freezing/thawing and freeze-drying and were sterilized by autoclaving. The macrostructure of the resulting hydrogels was investigated by scanning electron microscopy (SEM), showing a heterogeneous macroporous structure with a pore size between 50 and 500 μm. Fourier-transform infrared (FTIR) spectra showed that the three polymers interacted through hydrogen bonding between the amino and hydroxyl moieties. The profile of amino acids present in the gelatin and the hydrogel was determined by ultra-performance liquid chromatography (UPLC), suggesting that the majority of amino acids interacted during the formation of the hydrogel. The cytocompatibility, viability, cell growth and formation of extracellular matrix (ECM) proteins were evaluated to demonstrate the suitability and functionality of the 3D hydrogels for the culture of auricular chondrocytes. The cytocompatibility of the 3D hydrogels was confirmed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, reaching 100% viability after 72 h. Chondrocyte viability showed a high affinity of chondrocytes for the hydrogel after 14 days, using the Live/Dead assay. The chondrocyte attachment onto the 3D hydrogels and the formation of an ECM were observed using SEM. Immunofluorescence confirmed the expression of elastin, aggrecan and type II collagen, three of the main components found in an elastic cartilage extracellular matrix. These results demonstrate the suitability and functionality of a CS/Gel/PVA hydrogel as a 3D support for the auricular chondrocytes culture, suggesting that these hydrogels are a potential biomaterial for cartilage tissue engineering applications, aimed at the regeneration of elastic cartilage.

Different Sources of Bone Marrow Mesenchymal Stem Cells: A Comparison of Subchondral, Mandibular, and Tibia Bone-derived Mesenchymal Stem Cells

BACKGROUND

Stem cell properties vary considerably based on the source and tissue site of mesenchymal stem cells (MSCs). The mandibular condyle is a unique kind of craniofacial bone with a special structure and a relatively high remodeling rate. MSCs here may also be unique to address specific physical needs.

OBJECTIVE

The aim of this study was to compare the proliferation and multidirectional differentiation potential among MSCs derived from the tibia (TMSCs), mandibular ramus marrow (MMSCs), and condylar subchondral bone (SMSCs) of rats in vitro.

METHODS

Cell proliferation and migration were assessed by CCK-8, laser confocal, and cell scratch assays. Histochemical staining and real-time PCR were used to evaluate the multidirectional differentiation potential and DNA methylation and histone deacetylation levels.

RESULTS

The proliferation rate and self-renewal capacity of SMSCs were significantly higher than those of MMSCs and TMSCs. Moreover, SMSCs possessed significantly higher mineralization and osteogenic differentiation potential. Dnmt2, Dnmt3b, Hdac6, Hdac7, Hdac9, and Hdac10 may be instrumental in the osteogenesis of SMSCs. In addition, SMSCs are distinct from MMSCs and TMSCs with lower adipogenic differentiation and chondrogenic differentiation potential. The multidirectional differentiation capacities of TMSCs were exactly the opposite of those of SMSCs, and the results of MMSCs were intermediate.

CONCLUSION

This research offers a new paradigm in which SMSCs could be a useful source of stem cells for further application in stem cell-based medical therapies due to their strong cell renewal and osteogenic capacity.

Exosomes Derived from Runx2-Overexpressing BMSCs Enhance Cartilage Tissue Regeneration and Prevent Osteoarthritis of the Knee in a Rabbit Model

Objectives. Osteoarthritis is the leading disease of joints worldwide. Osteoarthritis may be treated by exosomes derived from Runx2-overexpressed bone marrow mesenchymal stem cells (R-BMSCs-Exos). R-BMSCs-Exos would promote the proliferation, migration, and phenotypic maintenance of articular chondrocytes. Methods. BMSCs were transfected with and without Runx2. Exosomes derived from BMSCs and R-BMSCs (BMSCs-Exos and R-BMSCs-Exos) were isolated and identified. Proliferation, migration, and phenotypic maintenance were determined in vitro and compared between groups. The mechanism for activation of Yes-associated protein (YAP) was investigated using small interfering RNA (siRNA). The exosomes’ preventive role was determined in vivo using Masson trichrome and immunohistochemical staining. Results. R-BMSCs-Exos enhance the proliferation, migration, and phenotypic maintenance of articular chondrocytes based on the YAP being activated. R-BMSCs-Exos prevent knee osteoarthritis as studied in vivo through a rabbit model. Conclusions. Findings emphasize the efficacy of R-BMSCs-Exos in preventing osteoarthritis. Potential source of exosomes is sorted out for the advantages and shortcomings. The exosomes are then modified based on the molecular mechanisms to address their limitations. Such exosomes derived from modified cells have the role in future therapeutics.

Berberine encapsulated in exosomes derived from platelet-rich plasma promotes chondrogenic differentiation of the Bone Marrow Mesenchymal Stem Cells via the Wnt/β-catenin pathway

Cartilage regenerative medicine, wherein the stem cells from adults exert a crucial role, has high potential in the treatment of defective articular cartilage. Recently, Bone marrow mesenchymal stem cells (BMSCs) are being increasingly recognized as an alternative source of adult stem cells, which are capable of differentiating into several cell types (e.g., adipocytes, chondrocytes, and osteoblasts). However, their proliferative properties and tendency to dedifferentiate restrict their use in clinical settings. Recently, a possible bioactive material PRP-exos (exosomes derived from platelet-rich plasma), has emerged, which can effectively facilitate the differentiation and proliferation of cells. Recent studies have reported that berberine (Ber), known to have anti-inflammatory properties, plays a role in osteogenesis. Since biological molecules are used in combinations, we attempted to assess the effect of Exos-Ber (PRP-exos in combination with Ber) on the chondrogenic differentiation of BMSCs in vitro. In this study, Exos-Ber was observed to promote the proliferation of BMSCs and cause their chondrogenic differentiation in vitro. Additionally, Exos-Ber could promote the migration of BMSCs and increase the protein expression of the chondrogenic genes (Collagen II, SOX9, Aggrecan). After treatment with Exos-Ber, significant induction of β-catenin expression was observed, which could be repressed successfully by adding β-catenin inhibitor XAV-939. Interestingly, the repression of the Wnt/β-catenin axis also resulted in reduced gene expression levels of Collagen II, SOX9, and Aggrecan. These observations indicated that Exos-Ber facilitated the differentiation of chondrogenic BMSCs by modulating the Wnt/β-catenin axis, which offers innovative insights into the reconstruction of cartilage.

An injectable hydroxypropyl-β-cyclodextrin cross-linked gelatin-based hydrogel loaded bone mesenchymal stem cell for osteogenic and in vivo bone regeneration of femoral head necrosis

An injectable hydroxypropyl-β-cyclodextrin (HPβCD) cross-linking of gelatin (Gel) based hydrogel was embedded with BMSC in vivo bone regeneration of femoral head necrosis. This HPβCD-Gel hydrogel possesses quick gelation within 6 min; a high-water uptake resulted in faster biodegradation, high swelling, and a 3D porous network that strengthened its mechanical, surface, and morphological properties. The results indicated that BMSC showed high cell viability (>90%) during measurement; HPβCD-Gel hydrogels induced BMSC differentiation into osteocytes within 14 days more efficiently than the osteogenic medium. The HPβCD-Gel/BMSC hydrogels that were injected into the necrosis site of the femoral head in the vessels were measured for 2 weeks. In addition, the vessel density and mean vessel diameters increased in the next 2-8 weeks followed by increased new bone formation, according to the in vivo analysis. Overall, our findings show that this method is a promising strategy for improving femoral head necrosis bone regeneration.