Regeneration Of Cartilage Defects Research Articles

Exosomes loaded a smart bilayer-hydrogel scaffold with ROS-scavenging and macrophage-reprogramming properties for repairing cartilage defect

Enhancing the regeneration of cartilage defects remains challenging owing to limited innate self-healing as well as acute inflammation arising from the overexpression of reactive oxygen species (ROS) in post-traumatic microenvironments. Recently, stem cell-derived exosomes (Exos) have been developed as potential cell-free therapy for cartilage regeneration. Although this approach promotes chondrogenesis, it neglects the emerging inflammatory microenvironment. In this study, a smart bilayer-hydrogel dual-loaded with sodium diclofenac (DC), an anti-inflammatory drug, and Exos from bone marrow-derived mesenchymal stem cells was developed to mitigate initial-stage inflammation and promote late-stage stem-cell recruitment and chondrogenic differentiation. First, the upper-hydrogel composed of phenylboronic-acid-crosslinked polyvinyl alcohol degrades in response to elevated levels of ROS to release DC, which mitigates oxidative stress, thus reprogramming macrophages to the pro-healing state. Subsequently, Exos are slowly released from the lower-hydrogel composed of hyaluronic acid into an optimal microenvironment for the stimulation of chondrogenesis. Both in vitro and in vivo assays confirmed that the dual-loaded bilayer-hydrogel reduced post-traumatic inflammation and enhanced cartilage regeneration by effectively scavenging ROS and reprogramming macrophages. The proposed platform provides multi-staged therapy, which allows for the optimal harnessing of Exos as a therapeutic for cartilage regeneration.

Cartilage regeneration using transforming growth factor-beta 3-loaded injectable crosslinked hyaluronic acid hydrogel.

Cartilage defects can be difficult to heal, potentially leading to complications such as osteoarthritis. Recently, a tissue engineering approach that uses scaffolds and growth factors has been proposed to regenerate new cartilage tissues. Herein, we investigated the application of hyaluronic acid (HA) gel loaded with transforming growth factor-beta 3 (TGF-β3) for enhanced cartilage regeneration. We assessed the clinical conditions required to efficiently enhance the ability of the modified HA gel to repair defective cartilage. Based on our findings, the prepared HA gel exhibited good physicochemical and mechanical properties and was non-toxic and non-inflammatory. Moreover, HA gel-loaded TGF-β3 (HAT) had improved biocompatibility and promoted the synthesis of cartilage-specific matrix and collagen, further improving its ability to repair defects. The application of HAT resulted in an initial burst release of HA, which degraded slowly in vivo. Finally, HAT combined with microfracture-inducing bone marrow stem cells could significantly improve the cartilage microenvironment and regeneration of cartilage defects. Our results indicate that HA is a suitable material for developing growth factor carriers, whereas HAT is a promising candidate for cartilage regeneration. Furthermore, this differentiated strategy provides a rapid and effective clinical approach for next-generation cartilage regeneration.

Injectable decellularized cartilage matrix hydrogel encapsulating urine-derived stem cells for immunomodulatory and cartilage defect regeneration

Reconstruction of complex cartilage defects has remained a great challenge for tissue engineering due to the lack of stem cells and chronic inflammation within the joint. In this study, we have developed an injectable pig cartilage-derived decellularized extracellular matrix (dECM) hydrogels for the repair of cartilage defects, which has shown sound biocompatibility and immunomodulatory capacity both in vitro and in vivo. The dECM hydrogels can enhance the chondrogenic differentiation of human urine-derived stem cells (USCs). As shown by in vitro experiment, the USCs in the dECM hydrogels have survived, proliferated, and produced a mass of cartilage-specific extracellular matrix containing collagen II and aggrecan. And the USCs-laden dECM hydrogels have shown the capacity to promote the secretion of extracellular matrix, modulate the immune response and promote cartilage regeneration in the rat model for cartilage defect.

Synovium-Derived Mesenchymal Stem Cells in Combination with Low Molecular Weight Hyaluronic Acid for Cartilage Repair

Regeneration of damaged articular cartilage remains one of the most complex and unresolved problems in traumatology and orthopedics. In this study, we investigated whether intra-articular injection of synovium-derived mesenchymal stem cells (SD-MSCs) with low molecular weight hyaluronic acid (LMWHA) could promote the regeneration of damaged cartilage in rabbits. To answer this question, rabbits' SD-MSCs were harvested, expanded in culture, and characterized by CFU assay and a multilineage differentiation test. For in vivo study, we created a defect within the cartilage layer without destroying subchondral bone. Two weeks after the cartilage defect, SD-MSCs (2×106 cells) were suspended in 0.5% LMWHA and injected into the left knee, and hyaluronic acid (HA) solution alone was placed into the right knee. Cartilage regeneration in experimental and control groups was evaluated macroscopically and histologically at Days 30, 60, and 90. The results of the study showed an early process of cartilage regeneration in the defect area on Day 30 after intra-articular MSCs-HA injection. Histological studies revealed that cartilage defect was covered by a thin layer of spindle-shaped undifferentiated cells and proliferated chondroblasts, in contrast to a single HA injection, which did not induce cartilage regeneration. On Day 60, we observed that the size of the cartilage defect after MSCs-HA injection significantly decreased, compared to one after HA injection. On Day 90, the cartilage defect in a knee treated with MSCs-HA was fully regenerated and was similar to intact cartilage. Thus, the combined application of the MSCs, HA, and chondroinductive proteins have a high therapeutic effect on cartilage defect regeneration in rabbits.

A Preclinical Study of Bone Marrow Buffy Coat Components and Cartilage Regeneration

Background: Autologous bone marrow buffy coat transplantation possesses obvious advantages in the therapy of cartilage defects. However, there is no definite research on the specific effective components of bone marrow buffy coat and their mechanism of cartilage regeneration. Moreover, bone marrow buffy coat is difficult to fix onto the damaged cartilage area. We evaluated the composition of Buffy coat and the combined use of hyaluronic acid (HA) as a scaffold material for repairing cartilage defects. Methods and Materials: We extracted the bone marrow from the anterior superior iliac crest of the rabbit, centrifuged it to obtain buffy coat, and analyzed the components of buffy coat by enzyme-linked immunosorbent assay (ELISA). Buffy coat+fibrinogen/HA group, mesenchymal stem cell (MSC)+fibrinogen/HA group, MSC+ Transforming Growth Factorβ(TGF-β)+ fibrinogen/HA group were culturedin vitroand observed by staining. In addition, we made damage to the femoral condyle of rabbits and divided them into groups: HA group, buffy coat group, buffy coat with HA group. Each group was assessed for cartilage regeneration by visual observation, histological at 4 weeks and 8 weeks, and biochemical analysis at 8 weeks postoperatively. One-way ANOVA and LSD were used for statistical analysis. Results: Buffy coat have a variety of growth factors, inflammatory factors, and anti-inflammatory factors that stimulate the MSCs’ regeneration. Buffy coat can differentiate into cartilage without TGF-βstimulationin vitro. The cartilage regeneration ability of buffy coat and buffy coat+HA is strong, and the combination of buffy coat and gel scaffold HA can make cartilage formation ability more stablein vivo. Conclusion: MSC and cytokines in buffy coat synergistically promote cartilage regeneration. Gel scaffold HA enhances the effect of buffy coat on cartilage attachment and regeneration of cartilage defects.

Size dependent regeneration capacity of functionalized Capra ear-derived micro-tissue scaffolds for treatment of cartilage defects

Regeneration of cartilage still possesses considerable challenge in orthopedic treatment owing to avascular nature and lack of self-healing ability of the tissue. In this context, cartilage defect recovery via engineered functional micro tissue delivery is an emerging trend in musculoskeletal therapeutics. This work explores the efficacy of Capra ear-derived functionalized micro-tissues (FMTs) for regeneration of cartilage defects. For this study, a novel and inexpensive NaOH-based decellularization method was developed and optimized to obtain complete removal of cells without deteriorating the matrix structure of Capra ear cartilage. The decellularized matrix was then processed to generate micro-scaffolds (MSs) with different size distributions. It was established that among those size groups, MSs having 100 µm average size were most effective for adherence, cell proliferation and differentiation. It was assessed that the loose fibrous structure of smaller scaffolds was able to induce chondrogenic differentiation. Further, a frugal system was devised for performing hanging culture on the MSs with adipose tissue derived mesenchymal stem cells (ADMSCs) to generate functionalized micro tissues (FMTs). Finally, FMTs were implanted in rabbit auricular cartilage defects to evaluate their healing efficacy. Histology, FTIR and microCT studies revealed that the implanted FMTs were able to regenerate the defect within 60 days. Thus, this work establishes that the functionalized micro tissues derived from decellularized capra ear cartilage can potentially be used for cartilage regeneration, and the efficacy of regeneration depends on the size along with the fibrous structure of the scaffolds.

Exosomes derived from hypoxia preconditioned mesenchymal stem cells laden in a silk hydrogel promote cartilage regeneration via the miR-205–5p/PTEN/AKT pathway

Tissue engineering has promising prospects for cartilage regeneration. However, there remains an urgent need to harvest high quality seed cells. Bone marrow mesenchymal cells (BMSCs), and in particular their exosomes, might promote the function of articular chondrocytes (ACs) via paracrine mechanisms. Furthermore, preconditioned BMSCs could provide an enhanced therapeutic effect. BMSCs naturally exist in a relatively hypoxic environment (1%–5% O2); however, they are usually cultured under higher oxygen concentrations (21% O2). Herein, we hypothesized that hypoxia preconditioned exosomes (H-Exos) could improve the quality of ACs and be more conducive to cartilage repair. In our study, we compared the effects of exosomes derived from BMSCs preconditioned with hypoxia and normoxia (N-Exos) on ACs, demonstrating that H-Exos significantly promoted the proliferation, migration, anabolism and anti-inflammation effects of ACs. Furthermore, we confirmed that hypoxia preconditioning upregulated the expression of miR-205–5p in H-Exos, suggesting that ACs were promoted via the miR-205–5p/PTEN/AKT pathway. Finally, an injectable silk fibroin (SF) hydrogel containing ACs and H-Exos (SF/ACs/H-Exos) was utilized to repair cartilage defects and effectively promote cartilage regeneration in vivo. The application of SF/ACs/H-Exos hydrogel in cartilage regeneration therefore has promising prospects. Statement of significanceCartilage tissue engineering (CTE) has presented a promising prospect. However, the quality of seed cells is an important factor affecting the repair efficiency. Our study demonstrates for the first time that the exosomes derived from hypoxia preconditioned BMSCs (H-Exos) effectively promote the proliferation, migration and anabolism of chondrocytes and inhibit inflammation through miR-205–5p/PTEN/AKT pathway. Furthermore, we fabricated an injectable silk fibrion (SF) hydrogel to preserve and sustained release H-Exos. A complex composed of SF hydrogel, H-Exos and chondrocytes can effectively promote the regeneration of cartilage defects. Therefore, this study demonstrates that hypoxia pretreatment could optimize the therapeutic effects of BMSCs-derived exosomes, and the combination of exosomes and SF hydrogel could be a promising therapeutic method for cartilage regeneration.

In situ regeneration of nasal septal defects using acellular cartilage enhanced with platelet-derived growth factor

Nasal septum defects can currently only be reconstructed using autologous cartilage grafts. In this study, we examine the reconstruction of septal cartilage defects in a rabbit model using porcine decellularized nasal septal cartilage (DNSC) functionalized with recombinant platelet-derived growth factor-BB (PDFG-BB). The supportive function of the transplanted DNSC was estimated by the degree of septum deviation and shrinkage using magnetic resonance imaging (MRI). The biocompatibility of the transplanted scaffolds was evaluated by histology according to international standards. A study group with an autologous septal transplant was used as a reference. In situ regeneration of cartilage defects was assessed by histological evaluation 4 and 16 weeks following DNSC transplantation. A study group with non-functionalized DNSC was introduced for estimation of the effects of PDFG-BB functionalization. DNSC scaffolds provided sufficient structural support to the nasal septum, with no significant shrinkage or septal deviations as evaluated by the MRI. Biocompatibility analysis after 4 weeks revealed an increased inflammatory reaction of the surrounding tissue in response to DNSC as compared to the autologous transplants. The inflammatory reaction was, however, significantly attenuated after 16 weeks in the PDGF-BB group whereas only a slight improvement of the biocompatibility score was observed in the untreated group. In situ regeneration of septal cartilage, as evidenced by the degradation of the DNSC matrix and production of neocartilage, was observed in both experimental groups after 16 weeks but was more pronounced in the PDFG-BB group. Overall, DNSC provided structural support to the nasal septum and stimulated in situ regeneration of the cartilage tissue. Furthermore, PDFG-BB augmented the regenerative potential of DNSC and enhanced the healing process, as demonstrated by reduced inflammation after 16 weeks.

Injectable Mussel‐Inspired highly adhesive hydrogel with exosomes for endogenous cell recruitment and cartilage defect regeneration

In the early stage of osteoarthritis (OA), cartilage degradation in the surface region leads to superficial cartilage defect. However, enhancing the regeneration of cartilage defect remains a great challenge for existing hydrogel technology because of the weak adhesion to wet tissue. In the present study, an injectable mussel-inspired highly adhesive hydrogel with exosomes was investigated for endogenous cell recruitment and cartilage defect regeneration. The hydrogel with high bonding strength to the wet surface was prepared using a crosslinked network of alginate-dopamine, chondroitin sulfate, and regenerated silk fibroin (AD/CS/RSF). Compared with commercial enbucrilate tissue adhesive, the AD/CS/RSF hydrogel provided a comparative lap shear strength of 120 kPa, with a similar gelation time and a higher capacity for maintaining adhesive strength. The AD/CS/RSF/EXO hydrogel with encapsulated exosomes recruited BMSCs migration and inflation, promoted BMSCs proliferation and differentiation. Most importantly, the AD/CS/RSF/EXO hydrogel accelerated cartilage defect regeneration in situ, and extracellular matrix remodeling after injection in rat patellar grooves. The exosomes released by the hydrogels could recruit BMSCs into the hydrogel and neo-cartilage via the chemokine signaling pathway. Our findings reveal an injectable and adhesive hydrogel for superficial cartilage regeneration, which is a promising approach for minimally treating cartilage defect with arthroscopic assistance.

Chitosan hydrogel/3D-printed poly(ε‐caprolactone) hybrid scaffold containing synovial mesenchymal stem cells for cartilage regeneration based on tetrahedral framework nucleic acid recruitment

Articular cartilage (AC) injury repair has always been a difficult problem for clinicians and researchers. Recently, a promising therapy based on mesenchymal stem cells (MSCs) has been developed for the regeneration of cartilage defects. As endogenous articular stem cells, synovial MSCs (SMSCs) possess strong chondrogenic differentiation ability and articular specificity. In this study, a cartilage regenerative system was developed based on a chitosan (CS) hydrogel/3D-printed poly(ε‐caprolactone) (PCL) hybrid containing SMSCs and recruiting tetrahedral framework nucleic acid (TFNA) injected into the articular cavity. TFNA, which is a promising DNA nanomaterial for improving the regenerative microenvironment, could be taken up into SMSCs and promoted the proliferation and chondrogenic differentiation of SMSCs. CS, as a cationic polysaccharide, can bind to DNA through electrostatic action and recruit free TFNA after articular cavity injection in vivo. The 3D-printed PCL scaffold provided basic mechanical support, and TFNA provided a good microenvironment for the proliferation and chondrogenic differentiation of the delivered SMSCs and promoted cartilage regeneration, thus greatly improving the repair of cartilage defects. In conclusion, this study confirmed that a CS hydrogel/3D-printed PCL hybrid scaffold containing SMSCs could be a promising strategy for cartilage regeneration based on chitosan-directed TFNA recruitment and TFNA-enhanced cell proliferation and chondrogenesis.

Effect of quercetin on chondrocyte phenotype and extracellular matrix expression

Due to the poor repair ability of cartilage tissue, regenerative medicine still faces great challenges in the repair of large articular cartilage defects. Quercetin is widely applied as a traditional Chinese medicine in tissue regeneration including liver, bone and skin tissues. However, the evidence for its effects and internal mechanisms for cartilage regeneration are limited. In the present study, the effects of quercetin on chondrocyte function were systematically evaluated by CCK8 assay, PCR assay, cartilaginous matrix staining assays, immunofluorescence assay, and western blotting. The results showed that quercetin significantly up-regulated the expression of chondrogenesis genes and stimulated the secretion of GAG (glycosaminoglycan) through activating the ERK, P38 and AKT signalling pathways in a dose-dependent manner. Furthermore, in vivo experiments revealed that quercetin-loaded silk protein scaffolds dramatically stimulated the formation of new cartilage-like tissue with higher histological scores in rat femoral cartilage defects. These data suggest that quercetin can effectively stimulate chondrogenesis in vitro and in vivo, demonstrating the potential application of quercetin in the regeneration of cartilage defects.

Collagen Type I and Type II Expression Evaluation on Cartilage Defect Regeneration Treated with Dwikora–Ferdiansyah–Lesmono–Purwati (DFLP) Scaffold Supplemented with Adipose–Derived Stem Cells (ASCs) or Secretome: An In-Vivo Study

Abstract Cell-based therapies such as Scaffold, stem cells, and secretome, are one of the alternatives to enhance the regeneration of hyaline-like cartilage in cases of cartilage defects. This study is an in-vivo experiment using animal models, in which we apply a composite of DFLP (Dwikora-Ferdiansyah-Lesmono-Purwati) Scaffold and Adipose-Derived Stem Cells (ASCs) or Secretome to an injury model on the distal femoral trochlea of New Zealand White Rabbits. The animals were divided into four groups: (1) control (K); (2) Scaffold only (S); (3) Scaffold + ASCs (SA); (4) Scaffold + Secretome (SS). Animals were terminated in the 12th week, and an immunohistochemistry (IHC) evaluation for Collagen type I and II were done. Statistical analysis shows that collagen type I IHC between groups shows no significant difference (p = 0.546). Collagen type II IHC shows significant difference between groups (p = 0,016). The findings in this study showed that Scaffold + ASCs group and Scaffold + Secretome have better collagen type II expression compared to the control group. DFLP Scaffold composite with ASCs or Secretome shows potential for cartilage regeneration therapy by increasing type II collagen expression as in hyaline-like cartilage which may be used for regenerative therapy for cartilage defects. Keywords : DFLP Scaffold; Adipose-Derived Stem Cells (ASCs); Secretome; Collagen Type I; Collagen Type IICorrespondence : ianperbowo@me.com

Injectable Therapeutic Organoids Using Sacrificial Hydrogels

SummaryOrganoids are becoming widespread in drug-screening technologies but have been used sparingly for cell therapy as current approaches for producing self-organized cell clusters lack scalability or reproducibility in size and cellular organization. We introduce a method of using hydrogels as sacrificial scaffolds, which allow cells to form self-organized clusters followed by gentle release, resulting in highly reproducible multicellular structures on a large scale. We demonstrated this strategy for endothelial cells and mesenchymal stem cells to self-organize into blood-vessel units, which were injected into mice, and rapidly formed perfusing vasculature. Moreover, in a mouse model of peripheral artery disease, intramuscular injections of blood-vessel units resulted in rapid restoration of vascular perfusion within seven days. As cell therapy transforms into a new class of therapeutic modality, this simple method—by making use of the dynamic nature of hydrogels—could offer high yields of self-organized multicellular aggregates with reproducible sizes and cellular architectures.

Rapid Cartilage Regeneration of Spheroids Composed of Human Nasal Septum-Derived Chondrocyte in Rat Osteochondral Defect Model.

Cell-based therapies have been studied for articular cartilage regeneration. Articular cartilage defects have little treatments because articular cartilage was limited regenerative capacity. Damaged articular cartilage is difficult to obtain a successful therapeutic effect. In additionally these articular cartilage defects often cause osteoarthritis. Chondrocyte implantation is a widely available therapy used for regeneration of articular cartilage because this tissue has poor repair capacity after injury. Human nasal septum-drived chondrocytes (hNCs) from the septum show greater proliferation ability and chondrogenic capacity than human articular chondrocytes (hACs), even across different donors with different ages. Moreover, the chondrogenic properties of hNCs can be maintained after extensive culture expansion. In this study, 2 dimensional (2D) monolayer cultured hNCs (hNCs-2D) and 3 dimensional (3D) spheroids cultured hNCs (hNCs-3D) were examined for chondrogenic capacity in vitro by PCR and immunofluorescence staining for chondrogenic marker, cell survival during cultured and for cartilage regeneration ability in vivo in a rat osteochondral defect model. hNCs-3D showed higher viability and more uniform morphology than 3D spheroids cultured hACs (hACs-3D) in culture. hNCs-3D also showed greater expression levels of the chondrocyte-specific marker Type II collagen (COL2A1) and sex-determining region Y (SRY)-box 9 (SOX9) than hNCs-2D. hNCs-3D also expressed chondrogenic markers in collagen. Specially, in the osteochondral defect model, implantation of hNCs-3D led to greater chondrogenic repair of focal cartilage defects in rats than implantation of hNCs-2D. These data suggest that hNCs-3D are valuable therapeutic agents for repair and regeneration of cartilage defects.

The effects of fibrin–icariin nanoparticle loaded in poly (lactic-co-glycolic) acid scaffold as a localized delivery system on chondrogenesis of human adipose-derived stem cells

Background:Nowadays, cartilage tissue engineering is the best candidate for regeneration of cartilage defects. This study evaluates the effect of fibrin/icariin (ICA) nanoparticles (F/I NPs) on chondrogenesis of stem cells.Materials and Methods:F/I NPs were characterized by Dynamic Light Scattering DLS. Poly (lactic-co-glycolic) acid (PLGA)-F/I NP scaffold was fabricated and assessed by scanning electron microscope. Human adipose-derived stem cells (hADSCs) were seeded on scaffold and induced for chondrogenesis. After 14 days, cell viability and gene expression were analyzed by the 3-(4, 5- dimethylthiazol-2yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. MTT assay and real-time polymerase chain reaction (RT-PCR).Results:The size and surface charge of F/I NP were about 28–30 nm and − 17, respectively. The average of pore size of PLGA and PLGA–fibrin/ICA was 230 and 340 μm, respectively. Cell viability of differentiated cells in P/F group was higher than others significantly (P ≤ 0.05). Furthermore, quantitative RT-PCR analysis demonstrated that ICA upregulated cartilaginous-specific gene expression. Furthermore, the results of the expression of type I collagen revealed that ICA downregulated this gene significantly (P < 0.01).Conclusions:The results indicated that F/I NP could be a potential factor for chondrogenesis of stem cells and downregulation of fibrocartilage marker.

Tough hydrogel with enhanced tissue integration and in situ forming capability for osteochondral defect repair

Articular cartilage repair still remains a major challenge in today's clinical practice due to its poor self-healing capacity. Therefore, it is essential to develop a promising strategy to achieve a one-step cartilage repair for patients suffering from joint diseases and traumas. Inspired by the complex composition and microscopic architecture of native articular cartilage, an injectable hydrogel (M-O-G) with tough mechanical property and strong tissue adhesiveness is developed. All hydrogel material compositions are natural polymers or their derivatives resemble the normal cartilage extracellular matrix (ECM). This hydrogel showed superior tunable mechanical properties (mechanical strength ≈270kPa, compressibility ≈70%) and rapid recovery ability. Moreover, it exhibited strong adhesiveness and enhanced integration with tissues. Further studies demonstrated that the hydrogel had good biocompatibility and superior performance in cartilage defect regeneration. Thus, the presented hydrogel is a promising biomaterial for clinical cartilage regeneration and other biomedical applications.

Cartilage Tissue Engineering Via Icariin and Adipose-derived Stem Cells in Fibrin Scaffold.

Background:Nowadays, cartilage tissue engineering is the best candidate for regeneration of cartilage defects. This study evaluates the function of herbal extracts icariin (ICA), the major pharmacological constituent of herba Epimedium, compared with transforming growth factor β3 (TGFβ3) to prove its potential effect for cartilage tissue engineering.Materials and Methods:ICA, TGFβ3, and TGFβ3 + ICA were added fibrin-cell constructions derived from adipose tissue stem cells. After 14 days, cell viability analyzed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H- tetrazolium bromide assay and the expression of cartilage genes was evaluated with real-time polymerase chain reaction (RT-PCR).Results:The results showed ICA, TGFβ3, and TGFβ3 + ICA increased the rate of proliferation and viability of cells; but there were no significant differences between them (P > 0.05). Furthermore, quantitative RT-PCR analysis demonstrated that cooperation of ICA with TGFβ3 showed a better effect in expression of cartilaginous specific genes and increased Sox9, type II collagen, and aggrecan expression significantly. Furthermore, the results of the expression of type I and X collagens revealed that TGFβ3 increased the expression of them (P < 0.01); However, treatment with ICA + TGFβ3 down regulated the expression of these genes significantly.Conclusion:The results indicated ICA could be a potential factor for chondrogenesis and in cooperation with TGFβ3 could reduce its hypertrophic effects and it is a promising factor for cartilage tissue engineering.

Effects of osteochondral defect size on cartilage regeneration using a double-network hydrogel

BackgroundThere has been increased interest in one-step cell-free procedures to avoid the problems related to cell manipulation and its inherent disadvantages. We have studied the chondrogenic induction ability of a PAMPS/PDMAAm double-network (DN) gel and found it to induce chondrogenesis in animal osteochondral defect models. The purpose of this study was to investigate whether the healing process and the degree of cartilage regeneration induced by the cell-free method using DN gel are influenced by the size of osteochondral defects.MethodsA total of 63 mature female Japanese white rabbits were used in this study, randomly divided into 3 groups of 21 rabbits each. A 2.5-mm diameter osteochondral defect was created in the femoral trochlea of the patellofemoral joint of bilateral knees in Group I, a 4.3-mm osteochondral defect in Group II, and a 5.8-mm osteochondral defect in Group III. In the right knee of each animal, a DN gel plug was implanted so that a vacant space of 2-mm depth was left above the plug. In the left knee, we did not conduct any treatment to obtain control data. Animals were sacrificed at 2, 4, and 12 weeks after surgery, and gross and histological evaluations were made.ResultsThe present study demonstrated that all sizes of the DN gel implanted defects as well as the 2.5mm untreated defects showed cartilage regeneration at 4 and 12 weeks. The 4.3-mm and 5.8-mm untreated defects did not show cartilage regeneration during the 12-week period. The quantitative score reported by O’Driscoll et al. was significantly higher in the 4.3-mm and 5.8-mm DN gel-implanted defects than the untreated defects at 4 and 12 weeks (p < 0.05). The 2.5-mm and 4.3-mm DN gel implanted defects maintained relatively high macroscopic and histological scores for the 12-week implantation period, while the histological score of the 5.8-mm DN gel implanted defect had decreased somewhat but statistically significantly at 12 weeks (p = 0.0057).ConclusionsThe DN gel induced cartilage regeneration in defects between 2.5 and 5.8 mm, offering a promising device to establish a cell-free cartilage regeneration therapy and applicable to various sizes of osteochondral defects.

In vivo repair of full-thickness cartilage defect with human iPSC-derived mesenchymal progenitor cells in a rabbit model.

Cell-based tissue engineering has the potential to restore cartilage defects. Induced pluripotent stem cells (iPSCs) are regarded as an alternative cell source in regenerative medicine. The purpose of the present study was to evaluate the use of mesenchymal stem cells (MSCs) derived from human iPSCs (hiPSCs) for the regeneration of cartilage defects in a rabbit model. Cartilage defects were made in the patellar grooves of New Zealand white rabbits. The rabbits were then divided into three groups according to implantation: Control group, scaffold implantation group and scaffold/hiPSCs-MSCs (experimental) group. MSCs were generated from hiPSCs via a step of embryoid body formation. Following flow cytological analysis, the hiPSCs-MSCs were plated onto poly(lactic-co-glycolide) and then transplanted into the cartilage defects in the experimental group. Six rabbits from each group were sacrificed at each time point. The outcome was assessed macroscopically and histologically at 3 and 6 weeks post-surgery. At 3 and 6 weeks, the experimental group showed more cartilage defect filling compared with the control and scaffold implantation groups. At 3 weeks, the experimental group showed much more repair tissue in the cartilage defect, although no cartilage-like tissue was observed. At 6 weeks, cartilage-like tissue was observed in the experimental group but not in the control or scaffold implantation groups. No teratoma formation was observed in any of the groups. The results indicate that iPSCs have the potential to repair cartilage defects in vivo. Therefore, iPSCs could be a new cell source for cartilage defect repair.

An in situ photocrosslinkable platelet rich plasma - Complexed hydrogel glue with growth factor controlled release ability to promote cartilage defect repair.

In this study, we have developed a photocrosslinkable platelet rich plasma (PRP) - complexed hydrogel glue (HNPRP) for cartilage regeneration. The in situ formed HNPRP hydrogel glue showed not only the controlled release ability of growth factors, but also strong tissue adhesiveness, which could resolve the current problems in clinical application of PRP. Furthermore, HNPRP hydrogel glue could promote integrative hyaline cartilage regeneration, and its reparative efficacy for cartilage defect was better than thrombin activated PRP gel. This study provided not only an effective repair material for cartilage regeneration, but also developed an advanced method for PRP application.