Repair of Articular Cartilage Defects With Cultured Chondrocytes on Polysulphonic Membrane: Experimental Studies in Rabbits

Role of autologous chondrocyte transplantation in articular cartilage defects: An experimental study

INTRODUCTION

Injuries of articular cartilage (AC) have very limited potential to heal, because they are avascular and this may subsequently lead to secondary arthrosis. Autologous cultured chondrocytes transplantation is can be used to create hyaline or hyaline-like repair in a cartilage defect area. The purpose of this study was to repair artificially created full-thickness AC defects in 20 rabbit knee joints with autologous cultured chondrocytes.

MATERIALS AND METHODS

An AC defect of 3 mm was created on the lateral condyle of both tibiae. The defect was filled with autologous chondrocytes cultured in vitro and fixed with fibrin, at a later stage on the left side. The right knee acted as a control. The rabbits were sacrificed after 3, 6, and 12 weeks of transplantation and the reparative tissues were analyzed macroscopically and histologically.

RESULTS

Histological scores of the cultured autologous chondrocyte transplanted knees were significantly better than the control knees at 3, 6, and 12 weeks following the transplantation. Integration of repaired tissue with adjacent cartilage, hyaline characteristics of repaired tissue, maturity of cartilage, and cellularity increases with duration and is significant in chondrocytes-transplanted defects compared to control. The histological scores also become better with increasing duration of followup.

CONCLUSION

Transplantation of autologous chondrocytes cultured in vitro and fixed with fibrin is effective in repairing AC defects.

Knee chondral injuries: clinical treatment strategies and experimental models

Articular cartilage has a very limited capacity to repair and as such premature joint degeneration is often the end point of articular injuries. Patients with chondral injury have asymptomatic periods followed by others in which discomfort or pain is bearable. The repair of focal cartilage injuries requires a precise diagnosis, a completed knee evaluation to give the correct indication for surgery proportional to the damage and adapted to each patient. Many of the surgical techniques currently performed involve biotechnology. The future of cartilage repair should be based on an accurate diagnosis using new MRI techniques. Clinical studies would allow us to establish the correct indications and surgical techniques implanting biocompatible and biodegradable matrices with or without stem cells and growth factors. Arthroscopic techniques with the design of new instruments can facilitate repair of patella and tibial plateau lesions.

Preclinical animal models in single site cartilage defect testing: a systematic review

OBJECTIVE

Review the literature for single site cartilage defect research and evaluate the respective strengths and weaknesses of different preclinical animal models.

METHOD

A literature search for animal models evaluating single site cartilage defects was performed. Variables tabulated and analyzed included animal species, age and number, defect depth and diameter and study duration. Cluster analyses were then used to separate animals with only distal femoral defects into similar groups based on defect dimensions. Representative human studies were included allowing comparison of common clinical lesions to animal models. The suitability of each species for single site cartilage defect research and its relevance to clinical human practice is then discussed.

RESULTS

One hundred thirteen studies relating to single site cartilage defects were reviewed. Cluster analysis included 101 studies and placed the murine, laprine, ovine, canine, porcine and caprine models in group 1. Group 2 contained ovine, canine, porcine, caprine and equine models. Group 3 contained only equine models and humans. Species in each group are similar with regard to defect dimensions. Some species occur in multiple groups reflecting utilization of a variety defect sizes. We report and discuss factors to be considered when selecting a preclinical animal model for single site cartilage defect research.

DISCUSSION

Standardization of study design and outcome parameters would help to compare different studies evaluating various novel therapeutic concepts. Comparison to the human clinical counterpart during study design may help increase the predictive value of preclinical research using animal models and improve the process of developing efficacious therapies.

Anabolic and catabolic function of chondrocyte ex vivo is reflected by the metabolic processing of type II collagen

OBJECTIVE

The aim of the present study was to investigate collagen metabolism after anabolic and catabolic stimulation of chondrocytes ex vivo.

DESIGN

Metabolic activities in ex vivo bovine cartilage explants were stimulated with insulin-like growth factor I (IGF-I) or a combination of tumor necrosis factor alpha (TNFalpha) and oncostatin M (OSM). Supernatants were assessed for changes in biochemical markers, N-terminal propeptide of type II (PIINP) collagen and fragments of C-telopeptide of type II collagen (CTX-II). Matrix metalloproteinases (MMP) were added to metabolic inactivated cartilage and evaluated by the two biochemical markers for formation or degradation, respectively. Finally, urinary CTX-II and PIINP were evaluated for assessment of type II collagen turnover in patients with rheumatoid arthritis (RA).

RESULTS

In the bovine articular cartilage explants, IGF-I induced an increase in PIINP level up to 4.8+/-1.1[ng/ml]/mg cartilage whereas CTX-II remained below 0.1+/-0.1[ng/ml]/mg cartilage. In the catabolic stimulated explants both PIINP and CTX-II were released to the supernatant, reaching concentrations of 9.0+/-1.4 and 9.1+/-2.2[ng/ml]/mg cartilage, respectively. RA patients had significantly lower serum concentrations of PIINP (3.4+/-3.7 ng/ml) compared with those healthy individuals (18.7+/-12.41 ng/ml, P<0.001). In contrast, RA patients had significantly higher urinary CTX-II (0.8+/-0.8 mg/mmol) compared to the healthy controls (0.1+/-0.08 mg/mmol, P=0.004).

CONCLUSIONS

This study is the first to demonstrate that precursors and degradation products of type II collagen released into the supernatant can effectively reflect the anabolic and catabolic activities of stimulated cartilage explants.