Stearic acid methyl ester ​promotes migration of mesenchymal stem cells and accelerates cartilage defect repair

Biomimetic Injectable Hydrogel Based on Methacrylate-Modified Silk Fibroin Embedded with Kartogenin for Superficial Cartilage Regeneration

The weak regeneration ability of chondrocytes is one of the main reasons that limit the therapeutic effect of clinical cartilage injury. Injectable hydrogels are potential scaffolds for cartilage tissue engineering with advantages such as minimally invasive surgery, porous structure, and drug sustained-release ability. At present, many biomaterials have been developed for the repair of deep cartilage defects. However, cartilage injury often begins on the surface, which requires us to propose a treatment strategy suitable for superficial cartilage injury repair. In this study, we fabricated a biomimetic injectable hydrogel based on methacrylate-modified silk fibroin (SilMA) embedded with kartogenin (KGN). The SilMA/KGN hydrogels have good biohistocompatibility and the ability to promote cartilage differentiation. In addition, SEM results show that it has a porous structure conducive to cell adhesion and proliferation. Most importantly, it has demonstrated remarkable superficial cartilage repair ability in vivo, showing potential in cartilage tissue engineering.

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.

Randomized control trial of mesenchymal stem cells versus hyaluronic acid in patients with knee osteoarthritis - A Hong Kong pilot study

Objective

This pilot study evaluated the efficacy of autologous bone marrow-derived mesenchymal stem cells (BM-MSCs) versus hyaluronic acid (HA) in surgically naïve patients with knee osteoarthritis (OA).

Methods

Single-centre, single-blind randomized study of patients with knee OA. Twenty patients were randomized into groups of 10 each for intra-articular injection of cultured BM-MSCs (6 ​ml of BM-MSCs at 1 ​× ​10⁶ ​cells/mL) or HA (6 ​ml). Clinical assessments of pain, quality of life, radiographic imaging, and magnetic resonance imaging (MRI) compositional change were performed at baseline and 12 months follow-up.

Results

Compared with HA, BM-MSCs injection resulted in significant improvement in qualify of life and reduction in pain as reflected by visual analogue scale (VAS) pain score, Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, and 36-Item Short Form Survey (SF-36) score collectively. T2-relaxation time tended to decrease more in the BM-MSCs group with a 38 ​± ​24.0% reduction in 6 out of 10 BM-MSC participants; while there was only a 12 ​± ​7.9% reduction in 4 out of 10 HA participants at the end of follow-up. The remaining participants showed either no response or had relaxation time increased on MRI assessment.

Conclusions

This pilot study found that autologous BM-MSCs significantly reduced pain, improved functional assessment score, and improved quality of life parameters comparing with HA at one year follow-up. Further clinical trial with larger sample size and longer follow up duration is warranted.

The Translational Potential of this Article

This pilot RCT demonstrated the feasibility and potential effectiveness of BM-MSCs advanced therapy for patients with knee OA compared to HA injection. Further multi-center clinical trial with a larger sample size and longer follow up duration in accordance with latest regulatory guidelines is warranted to ascertain the long term safety and effectiveness of MSCs therapy for cartilage regeneration in OA.

Registration

The study was registered in the Centre for Clinical Research Biostatistics - Clinical Trials Registry (CUHK_CCT00469).

Autologous Oxygen-Releasing Nano-Biomimetic Scaffold with Chondrocytes Promotes Joint Repair After Trauma

Our study assesses the role of a scaffold constructed by co-culture of autologous oxygen-releasing biomimetic scaffold (AONS) and chondrocytes in joint repair after trauma. A composite scaffold structure was used and a scaffold constructed of AONS and chondrocytes was transplanted into SD rats to create models of patellar cartilage fracture and hip osteochondral fracture, respectively followed by analysis of cell proliferation by immunofluorescence method, osteogenesis-related gene expression by RT-PCR, chondrocytes apoptosis by TUNEL staining. The blank control group and AONS composite chondrocytes have significant differences in apoptosis and cell proliferation of two fracture types (P <0.05). The autologous oxygen-releasing nanometers at 4 and 8 weeks showed a significant difference in the number of PCNA and TUNEL cells between biomimetic scaffold and chondrocytes in two groups (P < 0.05). The AONS and chondrocytes were effective for two types of fractures at 1, 4 and 8 weeks. The expression of various markers of intrachondral osteogenesis was decreased and the markers of hip osteochondral fracture were increased significantly (P < 0.05). Joint recovery was better than patellar cartilage fractures. The AONS composite chondrocyte scaffold promotes repair of patellar cartilage fractures and hip osteochondral fractures with a better effect on hip osteochondral fractures.

Modulation of Functional Characteristics of Mesenchymal Stromal Cells by Acellular Preparation of Porcine Hemoglobin

Exploring the potential usage of the acellular preparation of porcine hemoglobin (PHb) isolated from slaughterhouse blood as a cell culture media component, we have tested its effects on the functional characteristics of stromal cells of mesodermal origin. Human peripheral blood mesenchymal stromal cells (PB-MSCs) were used in this study as a primary cell model system, along with three mouse cell lines (ATDC5, MC3T3-E1, and 3T3-L1), which represent more uniform model systems. We investigated the effect of PHb at concentrations of 0.1, 1, and 10 μM on these cells’ proliferation, cycle, and clonogenic and migratory potential, and found that PHb’s effect depended on both the cell type and its concentration. At the lowest concentration used (0.1 μM), PHb showed the least evident impact on the cell growth and migration; hence, we analyzed its effect on mesenchymal cell multilineage differentiation capacity at this concentration. Even under conditions that induce a specific type of MSC differentiation (cultivation in particular differentiation media), PHb modulated chondrogenic, osteogenic, and adipogenic differentiation, making it a potential candidate for a supplement of MSC culture. Through a model of porcine hemoglobin, these findings also contribute to improving the knowledge of extracellular hemoglobin’s influence on MSCs >in vivo.

Local delivery of FTY720 induces neutrophil activation through chemokine signaling in an oronasal fistula model

Purpose

Cleft palate repair surgeries lack a regenerative reconstructive option and, in many cases, develop complications including oronasal fistula (ONF). Our group has developed a novel murine phenocopy of ONF to study the oral cavity wound healing program. Using this model, our team previously identified that delivery of FTY720 on a nanofiber scaffold had a unique immunomodulatory effect directing macrophages and monocytes into a pro-regenerative state during ONF healing. Here, the objective of this study was to determine the effects of local biomaterial-based FTY720 delivery in the ONF model on the early bulk gene expression and neutrophil phenotypic response within the regenerating tissue.

Methods

Using a mouse model of ONF formation, a palate defect was created and was treated with FTY720 nanofiber scaffolds or (blank) vehicle control nanofibers. At 1 and 3 days post-implantation, ONF oral mucosal tissue from the defect region was collected for RNA sequencing analysis or flow cytometry. For the RNA-seq expression profiling, intracellular pathways were assessed using the KEGG Pathway database and Gene Ontology (GO) Terms enrichment interactive graph. To assess the effects of FTY720 on different neutrophil subpopulations, flow cytometry data was analyzed using pseudotime analysis based on Spanning-tree Progression Analysis of Density-normalized Events (SPADE).

Results

RNA sequencing analysis of palate mucosa injured tissue identified 669 genes that were differentially expressed (DE) during the first 3 days of ONF wound healing after local delivery of FTY720, including multiple genes in the sphingolipid signaling pathway. Evaluation of the DE genes at the KEGG Pathway database also identified the inflammatory immune response pathways (chemokine signaling, cytokine-cytokine receptor interaction, and leukocyte transendothelial migration), and the Gene Ontology enrichment analysis identified neutrophil chemotaxis and migration terms. SPADE dendrograms of CD11b⁺Ly6G⁺ neutrophils at both day 1 and day 3 post-injury showed significantly distinct subpopulations of neutrophils in oral mucosal defect tissue from the FTY720 scaffold treatment group compared to the vehicle control group (blank). Increased expression of CD88 and Vav1, among other genes, were found and staining of the ONF area demonstrated increased VAV1 staining in FTY720‐treated healing oral mucosa.

Conclusion

Treatment of oral mucosal defects using FTY720 scaffolds is a promising new immunotherapy to improve healing outcomes and reducing ONF formation during cleft palate surgical repair. Local delivery of FTY720 nanofiber scaffolds during ONF healing significantly shifted early gene transcription associated with immune cell recruitment and modulation of the immune microenvironment results in distinct neutrophil subpopulations in the oral mucosal defect tissue that provides a critical shift toward pro-regenerative immune signaling.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40883-021-00208-z.

Bilayered scaffold with 3D printed stiff subchondral bony compartment to provide constant mechanical support for long-term cartilage regeneration

BACKGROUND/OBJECTIVE

We seek to figure out the effect of stable and powerful mechanical microenvironment provided by Ti alloy as a part of subchondral bone scaffold on long-term cartilage regeneration.Methods: we developed a bilayered osteochondral scaffold based on the assumption that a stiff subchondral bony compartment would provide stable mechanical support for cartilage regeneration and enhance subchondral bone regeneration. The subchondral bony compartment was prepared from 3D printed Ti alloy, and the cartilage compartment was created from a freeze-dried collagen sponge, which was reinforced by poly-lactic-co-glycolic acid (PLGA).

RESULTS

In vitro evaluations confirmed the biocompatibility of the scaffold materials, while in vivo evaluations demonstrated that the mechanical support provided by 3D printed Ti alloy layer plays an important role in the long-term regeneration of cartilage by accelerating osteochondral formation and its integration with the adjacent host tissue in osteochondral defect model at rabbit femoral trochlea after 24 weeks.

CONCLUSION

Mechanical support provided by 3D printing Ti alloy promotes cartilage regeneration by promoting subchondral bone regeneration and providing mechanical support platform for cartilage synergistically.

TRANSLATIONAL POTENTIAL STATEMENT

The raw materials used in our double-layer osteochondral scaffolds are all FDA approved materials for clinical use. 3D printed titanium alloy scaffolds can promote bone regeneration and provide mechanical support for cartilage regeneration, which is very suitable for clinical scenes of osteochondral defects. In fact, we are conducting clinical trials based on our scaffolds. We believe that in the near future, the scaffold we designed and developed can be formally applied in clinical practice.

Cyasterone accelerates fracture healing by promoting MSCs migration and osteogenesis

Background

Mesenchymal Stem Cells (MSCs) therapy has become a new coming focus of clinical research in regenerative medicine. However, only a small number of implanted MSCs could successfully reach the injured areas. The previous studies have shown that fracture healing time is inversely proportional to concentration of MSCs in injured tissue.

Methods

The migration and osteogenesis of MSCs were assessed by transwell assay and Alizarin Red S staining. Levels of gene and protein expression were checked by qPCR and Western Blot. On the other hand, the enhanced migration ability of MSCs induced by Cyasterone was retarded by CXCR4 siRNA. In addition, the rat model of femoral fracture was established to evaluate the effect of Cyasterone on fracture healing. What's more, we also checked the effect of Cyasterone on mobilisation of MSCs in vivo.

Results

The results showed that Cyasteron increased the number of MSCs in peripheral blood. The concentrations of SDF-1α in serum at different time points were determined by ELISA assay. Micro-CT and histological analysis were used to evaluate the fractured femurs.Our results showed that Cyasterone could promote the migration and osteogenesis capacities of MSCs. The fractured femurs healed faster with treatment of Cyasterone. Meanwhile, Cyasterone could significantly increase the level of SDF-1α in rats with femur fracture.

Conclusion

Cyasterone could promote migration and osteogenesis of MSCs, and most importantly, it could accelerate bone fracture healing.

Translational Potential statement: These findings provide evidence that Cyasterone could be used as a therapeutic reagent for MSCs mobilisation and osteogenesis. What's more, it could acclerate fracture healing.