Regeneration Of Articular Cartilage Defects Research Articles

Regenerative Medicine: where their origin makes species meet

The articular cartilage of joints serves diverse functions, including absorbing shock, transmitting force, and enabling low-friction joint motion. Regeneration of articular cartilage defects remains, however, a significant challenge in both human and veterinary orthopaedic practice. Ex vivo and in vivo models play a crucial role in translating novel potential regenerative treatments from bench to bedside. However, in view of the predictive power of these models and the One Medicine concept that proclaim that there should be no dividing lines between human and animal medicine to learn, it is important to understand the similarities as well as differences in the cartilage tissue between species. To this aim, osteochondral cores of the femoral condyles were studied in 58 different mammalian species ranging from mouse to elephant. Interestingly, while biochemical composition remained relatively constant, cartilage thickness and cellularity were similar underscoring the importance of the equine species as a model for human orthopaedic interventions. Nevertheless, political ambition and societal pressure are now asking for a drastically reduction of animal experimentation and have further spiked the development of more predictive in vitro and ex vivo models. In addition to a range of more sophisticated in vitro assays, this has now also provided an ex vivo osteochondral defect model that can be generated based on equine donor tissue. Although such models better represent the situation in the native tissue and can be used to assess (osteo)chondral repair strategies, they still lack some important aspects of the in vivo (patho)physiological (inflammatory) environment, as well as the exposure to mechanical loading. This illustrates the challenges that we still face in translating these novel approaches from bench to bedside.

Research advance in chondrogenic differentiation of adipose-derived stem cells

Articular cartilage lesions due to injury or other pathology are often difficult to heal, and the outcomes of the clinical treatment widely used today are far from satisfaction. Adipose-derived stem cells (ADSCs) are multipotent stem cells from adipose tissue. Tissue engineering based on the ability of ADSCs to differentiate into chondrocytes provides a new idea for the repair and regeneration of articular cartilage defects. The method for inducing the differentiation of ADSCs into chondrocytes in vitro who have been quite well established, which mainly include the use of growth factors and scaffolds to mimic the in vivo microenvironment, thereby promoting the differentiation of ADSCs into chondrocytes.

Similar regeneration of articular cartilage defects with autologous & allogenic chondrocytes in a rabbit model.

Background & objectives:Articular cartilage defects in the knee have a very poor capacity for repair due to avascularity. Autologous chondrocyte transplantation (ACT) is an established treatment for articular cartilage defects. Animal studies have shown promising results with allogenic chondrocyte transplantation since articular cartilage is non-immunogenic. In addition to being economical, allogenic transplantation has less morbidity compared to ACT. This study was undertaken to compare ACT with allogenic chondrocyte transplantation in the treatment of experimentally created articular cartilage defects in rabbit knee joints.Methods:Cartilage was harvested from the left knee joints of six New Zealand white rabbits (R1-R6). The harvested chondrocytes were cultured to confluence and transplanted onto a 3.5 mm chondral defect in the right knees of 12 rabbits [autologous in 6 rabbits (R1-R6) and allogenic in 6 rabbits (R7-R12)]. After 12 wk, the rabbits were euthanized and histological evaluation of the right knee joints were done with hematoxylin and eosin and safranin O staining. Quality of the repair tissue was assessed by the modified Wakitani histological grading scale.Results:Both autologous and allogenic chondrocyte transplantation resulted in the regeneration of hyaline/mixed hyaline cartilage. The total histological scores between the two groups showed no significant difference.Interpretation & conclusions:Allogenic chondrocyte transplantation seems to be as effective as ACT in cartilage regeneration, with the added advantages of increased cell availability and reduced morbidity of a single surgery.

Cartilage Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells in Three-Dimensional Silica Nonwoven Fabrics

In cartilage tissue engineering, three-dimensional (3D) scaffolds provide native extracellular matrix (ECM) environments that induce tissue ingrowth and ECM deposition for in vitro and in vivo tissue regeneration. In this report, we investigated 3D silica nonwoven fabrics (Cellbed®) as a scaffold for mesenchymal stem cells (MSCs) in cartilage tissue engineering applications. The unique, highly porous microstructure of 3D silica fabrics allows for immediate cell infiltration for tissue repair and orientation of cell–cell interaction. It is expected that the morphological similarity of silica fibers to that of fibrillar ECM contributes to the functionalization of cells. Human bone marrow-derived MSCs were cultured in 3D silica fabrics, and chondrogenic differentiation was induced by culture in chondrogenic differentiation medium. The characteristics of chondrogenic differentiation including cellular growth, ECM deposition of glycosaminoglycan and collagen, and gene expression were evaluated. Because of the highly interconnected network structure, stiffness, and permeability of the 3D silica fabrics, the level of chondrogenesis observed in MSCs seeded within was comparable to that observed in MSCs maintained on atelocollagen gels, which are widely used to study the chondrogenesis of MSCs in vitro and in vivo. These results indicated that 3D silica nonwoven fabrics are a promising scaffold for the regeneration of articular cartilage defects using MSCs, showing the particular importance of high elasticity.

Repair of articular cartilage in rabbit osteochondral defects promoted by extracorporeal shock wave therapy

This study investigated the stimulative effect of extracorporeal shock wave therapy (ESWT) on the articular cartilage regeneration in the rabbit osteochondral defect model for the first time. An osteochondral defect, 3 mm in diameter and 3 mm in depth, was drilled in the patellar groove at the distal end of each femur in 24 mature New Zealand rabbits. The right patellar defects received 500 impulses of shock waves of \(1.2 \hbox { mJ}/\hbox {mm}^{2}\) (at 14 kV) at 1 week after surgery and were designated as the experimental samples; the left patellar defects served as control. At 4, 8, and 12 weeks after ESWT, cartilage repair was evaluated macroscopically and histologically using a semiquantitative grading scale. The total scores of the macroscopic evaluation at 4, 8, and 12 weeks in the experimental group were superior to those in the control group (statistical significance level \(P < 0.05\)). As to the total scores of the histologic evaluation, the experimental group showed a tendency toward a better recovery than the control group at 4 weeks (\(0.05 < P < 0.1\)). At 8 and 12 weeks the differences between the experimental and control groups became mild and had no significance on statistical analysis. These findings suggested that regeneration of articular cartilage defects might be promoted by ESWT, especially at the early stage. The easy and safe ESWT is potentially viable for clinical application.

Reparation of chondral defects in rabbits by autologous and allogenous chondrocytes seeded on collagen/hyaluronan scaffold or suspended in fibrin glue

Abstract The topic of the study was to verify in vivo survival of in vitro cultured autologous and allogenous chondrocytes suspended in a fibrin glue Beriplast® or seeded on Collagen type I-Hyaluronan (Col type I-HYA) scaffolds for the regeneration of articular cartilage defects in rabbits. The study was carried out on 15 domestic rabbits randomly assigned to five groups (n = 3 in each) with different treatments of artificially created chondral defects (ChD´s). These defects were made in a non-load-bearing area of medial condyle of the distal femur, and were treated as follows: 1st and 3rd group: the ChD´s were filled with autologous or allogenous chondrocytes seeded on Col type I-HYA scaffolds, respectively. The scaffolds were fixed to the ChD´s by fibrin glue Beriplast®; 2nd and 4th group: the ChD´s were filled with a suspension of autologous or allogenous chondrocytes in fibrin glue Beriplast®, respectively, and they were immediately covered by unseeded Col type I-HYA scaffolds; Control group: the ChD´s were left to heal spontaneously without any treatment. Macroscopical, histological and immunohistochemical analyses of the ChD´s were performed 12 months after the treatment. In all treated groups, the chondrocytes were capable to proliferate and produce the cartilage extracellular matrix, including proteoglycans and type II collagen, as compared to the control “untreated” group. On the other hand, the production of hyaline-like cartilage tissue confirmed that both therapeutic methods using autologous chondrocytes can be applied successfully for the treatment of chondral defects in rabbits.

Enhanced migration of human bone marrow stromal cells in modified collagen hydrogels

Collagen I hydrogels are widely used as scaffolds for regeneration of articular cartilage defects. We hypothesised that ingrowth might be improved by removing the superficial layer of a compressed hydrogel. The control group consisted of the original unmodified product. The migration of human bone marrow stromal cells (hBMSCs) into the hydrogel was evaluated by confocal microscopy. We quantified the DNA concentration of the hydrogel for each group and time point and evaluated the chondrogenic differentiation of cells. After one week, the detectable amount of cells at the depth of 26-50 μm was significantly higher in the modified matrix (MM) than in the non-modified matrix (NM) (p = 0.011). The maximum depth of penetration was 75 μm (NM) and 200 μm (MM). After three weeks, the maximum depth of penetration was 175 μm (NM) and 200 μm (MM). Likewise, at a depth of 0-25 μm the amount of detectable cells was significantly higher in the MM group (p = 0.003). After 14 days, the concentration of DNA was significantly higher in the samples of the MM than in the control group (p = 0.000). Staining of histological sections and labelling with collagen II antibodies showed that a chondrogenic differentiation of cells in the scaffold can occur during in vitro cultivation. Removing the superficial layer is essential to ensuring proper ingrowth of cells within the compressed hydrogel. Compressed hydrogels contribute better to cartilage regeneration after surface modification.

Implantation of platelet-rich fibrin and cartilage granules facilitates cartilage repair in the injured rabbit knee: preliminary report

Autologous chondrocyte implantation has become the current principal procedure for cell-based cartilage repair.1,2 However, the disadvantages of autologous chondrocyte implantation include the necessity to perform two surgical procedures: isolation of the chondrocytes from a tissue sample that has been extracted from the patient, which is time-consuming, and implantation of the harvested chondrocytes after expansion in vitro,3 which has the potential to induce chondrocyte leakage.4 Platelet-rich fibrin (PRF) is a new generation of platelet concentrate that, without anticoagulant, activates the platelets of a blood sample and induces degranulation and cytokine release.5 The preparation of PRF is simple and can be completed during one procedure. In dental procedures, when a cystic cavity is filled with PRF, the physiological healing period can be reduced to two months instead of the usual 6 to 12 months.6 The aim of this study was to investigate the regeneration of articular cartilage defects of the knee following the implantation of PRF with cartilage granules in a one-step procedure in rabbits using T2-map magnetic resonance imaging (MRI) and histology to assess the rabbits' response to the procedure.

Spatiotemporal control of proliferation and differentiation of bone marrow–derived mesenchymal stem cells recruited using collagen hydrogel for repair of articular cartilage defects

Articular cartilage has a poor healing capacity, and cartilage regeneration is not always warranted to achieve healing. On the other hand, collagen scaffolds have been shown to support regeneration of articular cartilage defects in animal models, whereas bone morphogenetic protein-2 (BMP-2) is known to cause chondrogenic differentiation of marrow-derived mesenchymal stem cells (MSCs). The purpose of this study was to evaluate the effectiveness of intra-articular administration of BMP-2 into bone marrow-derived MSCs recruited to defects using original collagen hydrogel in rabbits at various time points. Full-thickness defects were created in both knees, then collagen hydrogels were transplanted, and BMP-2 was supplied for 1-week periods, as follows. BMP-2 was administered immediately after the operation for 1 week (BMP0-1 group), and BMP-2 was administered between weeks 1 and 2 after the operation (BMP1-2 group). BMP2 was administered between weeks 2 and 3 (BMP2-3 group). Specimens were then obtained, and bromodeoxyuridine (BrdU)-positive cells were enumerated and histologic grading was also performed. In addition, the gene expression analysis was performed using quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) assays. Enumeration of BrdU-positive cells showed a significant increase in the BMP0-1 group compared with the other groups. Similarly, histologic scores in the BMP0-1 group were superior for up to 8 weeks. Finally, RT-PCR findings revealed that immediate BMP-2 administration enhanced chondrogenic differentiation.

Regeneration of articular cartilage defects in the temporomandibular joint of rabbits by fibroblast growth factor-2: a pilot study

The purpose of this study was to investigate the therapeutic usefulness of fibroblast growth factor-2 (FGF-2) in rabbit temporomandibular joints (TMJ) with osteoarthritis. A 10-mm 3 defect was bored in the surface of the mandibular condyle head. The animals were divided into four groups: two test groups in which the defect was filled with lyophilized collagen containing 0.1 or 1.0 μg of FGF-2, and two control groups, in which the defects were filled with lyophilized collagen without FGF-2 or left empty. The defective sites were examined under a light microscope 3 weeks after surgery. Initiation of cartilage formation was observed in the defects filled with 0.1 μg of FGF-2, but only a small amount of cartilage was found in the defects of the 1.0-μg FGF-2- treated group. In the control groups, soft-tissue repair only or no tissue repair was found. In vivo, a dose of 0.1 μg of FGF-2 can stimulate articular cartilage restoration in defects of the TMJ in rabbits, although determining the effective concentration range of FGF-2 may be difficult. The present results suggest that an optimum concentration of FGF-2 could restore defects of TMJ articular cartilage clinically.

Human polymer-based cartilage grafts for the regeneration of articular cartilage defects

The use of autologous chondrocyte implantation (ACI) and its further development combining autologous chondrocytes with bioresorbable matrices may represent a promising new technology for cartilage regeneration in orthopaedic research. Aim of our study was to evaluate the applicability of a resorbable three-dimensional polymer of pure polyglycolic acid (PGA) for the use in human cartilage tissue engineering under autologous conditions. Adult human chondrocytes were expanded in vitro using human serum and were rearranged three-dimensionally in human fibrin and PGA. The capacity of dedifferentiated chondrocytes to re-differentiate was evaluated after two weeks of tissue culture in vitro and after subcutaneous transplantation into nude mice by propidium iodide/fluorescein diacetate (PI/FDA) staining, scanning electron microscopy (SEM), gene expression analysis of typical chondrocyte marker genes and histological staining of proteoglycans and type II collagen. PI/FDA staining and SEM documented that vital human chondrocytes are evenly distributed within the polymer-based cartilage tissue engineering graft. The induction of the typical chondrocyte marker genes including cartilage oligomeric matrix protein (COMP) and cartilage link protein after two weeks of tissue culture indicates the initiation of chondrocyte re-differentiation by three-dimensional assembly in fibrin and PGA. Histological analysis of human cartilage tissue engineering grafts after 6 weeks of subcutaneous transplantation demonstrates the development of the graft towards hyaline cartilage with formation of a cartilaginous matrix comprising type II collagen and proteoglycan. These results suggest that human polymer-based cartilage tissue engineering grafts made of human chondrocytes, human fibrin and PGA are clinically suited for the regeneration of articular cartilage defects.

Treatment of posttraumatic and focal osteoarthritic cartilage defects of the knee with autologous polymer-based three-dimensional chondrocyte grafts: 2-year clinical results

Autologous chondrocyte implantation (ACI) is an effective clinical procedure for the regeneration of articular cartilage defects. BioSeed®-C is a second-generation ACI tissue engineering cartilage graft that is based on autologous chondrocytes embedded in a three-dimensional bioresorbable two-component gel-polymer scaffold. In the present prospective study, we evaluated the short-term to mid-term efficacy of BioSeed-C for the arthrotomic and arthroscopic treatment of posttraumatic and degenerative cartilage defects in a group of patients suffering from chronic posttraumatic and/or degenerative cartilage lesions of the knee. Clinical outcome was assessed in 40 patients with a 2-year clinical follow-up before implantation and at 3, 6, 12, and 24 months after implantation by using the modified Cincinnati Knee Rating System, the Lysholm score, the Knee injury and Osteoarthritis Outcome Score, and the current health assessment form (SF-36) of the International Knee Documentation Committee, as well as histological analysis of second-look biopsies. Significant improvement (p < 0.05) in the evaluated scores was observed at 1 and/or 2 years after implantation of BioSeed-C, and histological staining of the biopsies showed good integration of the graft and formation of a cartilaginous repair tissue. The Knee injury and Osteoarthritis Outcome Score showed significant improvement in the subclasses pain, other symptoms, and knee-related quality of life 2 years after implantation of BioSeed-C in focal osteoarthritic defects. The results suggest that implanting BioSeed-C is an effective treatment option for the regeneration of posttraumatic and/or osteoarthritic defects of the knee.

Articular cartilage repair of rabbit chondral defect: promoted by creation of periarticular bony defect

This study investigated the stimulatory effect of bone healing on cartilage regeneration. Full-thickness osteochondral defects, 5 mm wide × 3mm deep, were created in the patellar groove of the right distal end of the femur in 60 mature Japanese white rabbits. The bone defect was made in the medial condyle of the ipsilateral tibia in the experimental group. The control group had only a chondral defect in the patellar groove. At 4, 8, and 12 weeks after surgery, cartilage repair was evaluated macroscopically and histologically using a semiquantitative grading scale. The mean scores of the gross and histological evaluation grade in the experimental group were significantly superior to those in the control group at 8 and 12 weeks (P < 0.05). These findings suggested that regeneration of articular cartilage defects might be promoted by creation of a periarticular bony defect.

S6-2 - Regeneration of articular cartilage defects

S6-2 - Regeneration of articular cartilage defects