Biological reconstruction of the joint: Concepts of articular cartilage regeneration and their scientific basis

Arthroscopic Implantation of a Cell-Free Bilayer Scaffold for the Treatment of Knee Chondral Lesions: A 2-Year Prospective Study

OBJECTIVE

The main objective of this study is to assess the safety and clinical efficacy of a cell-free bilayer scaffold (MaioRegen Chondro+ by Fin-Ceramica) in patients affected by chondral knee lesions of different origin and localization.

DESIGN

Thirty-one patients with focal chondral lesions of the knee were arthroscopically treated with MaioRegen Chondro+. All patients were prospectively evaluated for a minimum of 2 years using the International Knee Documentation Committee (IKDC) Questionnaire and the Tegner Activity Scale. Cartilage repair was assessed based on the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) 2.0 score at 12 months. Follow-up at 36 months was available for 25 out of 31 patients.

RESULTS

From baseline to 6-, 12-, and 24-month follow-up, IKDC score significantly improved by 19.5 ± 7.27 (95% confidence interval [CI]: 16.9-22.2, P < 0.001), 30.8 ± 7.63 (95% CI: 28.0-33.6, P < 0.001), and 36.2 ± 8.00 points (95% CI: 33.3-39.2, P < 0.001), respectively. Tegner scores documented a substantial clinical improvement as early as 12 months after surgery (change of -0.6 ± 0.62; 95% CI: -0.8 to -0.4, P < 0.001), reaching the preinjury values. There was a statistically significant increase in the MOCART scores (P < 0.001). Comparable results were observed regardless of preintervention demographic characteristics, lesion site or etiology, or the number of treated sites. Notably, the significant clinical benefit was maintained in a subset of patients who reached 3-year follow-up. No adverse events were reported in the entire analyzed population.

CONCLUSION

MaioRegen Chondro+ is a safe and effective device for the treatment of knee chondral lesions, enabling a significant clinical improvement for at least 2 years.

NGF-BMSC-SF/CS composites for repairing knee joint osteochondral defects in rabbits: evaluation of the repair effect and potential underlying mechanisms

BACKGROUND

With the rapid growth of the ageing population, chronic diseases such as osteoarthritis have become one of the major diseases affecting the quality of life of elderly people. The main pathological manifestation of osteoarthritis is articular cartilage damage. Alleviating and repairing damaged cartilage has always been a challenge. The application of cartilage tissue engineering methods has shown promise for articular cartilage repair. Many studies have used cartilage tissue engineering methods to repair damaged cartilage and obtained good results, but these methods still cannot be used clinically. Therefore, this study aimed to investigate the effect of incorporating nerve growth factor (NGF) into a silk fibroin (SF)/chitosan (CS) scaffold containing bone marrow-derived mesenchymal stem cells (BMSCs) on the repair of articular cartilage defects in the knees of rabbits and to explore the possible underlying mechanism involved.

MATERIALS AND METHODS

Nerve growth factor-loaded sustained-release microspheres were prepared by a double emulsion solvent evaporation method. SF/CS scaffolds were prepared by vacuum drying and chemical crosslinking. BMSCs were isolated and cultured by density gradient centrifugation and adherent culture. NGF-SF/CS-BMSC composites were prepared and implanted into articular cartilage defects in the knees of rabbits. The repair of articular cartilage was assessed by gross observation, imaging and histological staining at different time points after surgery. The repair effect was evaluated by the International Cartilage Repair Society (ICRS) score and a modified Wakitani score. In vitro experiments were also performed to observe the effect of different concentrations of NGF on the proliferation and directional differentiation of BMSCs on the SF/CS scaffold.

RESULTS

In the repair of cartilage defects in rabbit knees, NGF-SF/CS-BMSCs resulted in higher ICRS scores and lower modified Wakitani scores. The in vitro results showed that there was no significant correlation between the proliferation of BMSCs and the addition of different concentrations of NGF. Additionally, there was no significant difference in the protein and mRNA expression of COL2a1 and ACAN between the groups after the addition of different concentrations of NGF.

CONCLUSION

NGF-SF/CS-BMSCs improved the repair of articular cartilage defects in the knees of rabbits. This repair effect may be related to the early promotion of subchondral bone repair.

Cartilage tissue engineering using decellularized biomatrix hydrogel containing TGF-β-loaded alginate microspheres in mechanically loaded bioreactor

Physiochemical tissue inducers and mechanical stimulation are both efficient variables in cartilage tissue fabrication and regeneration. In the presence of biomolecules, decellularized extracellular matrix (ECM) may trigger and enhance stem cell proliferation and differentiation. Here, we investigated the controlled release of transforming growth factor beta (TGF-β1) as an active mediator of mesenchymal stromal cells (MSCs) in a biocompatible scaffold and mechanical stimulation for cartilage tissue engineering. ECM-derived hydrogel with TGF-β1-loaded alginate-based microspheres (MSs) was created to promote human MSC chondrogenic development. Ex vivo explants and a complicated multiaxial loading bioreactor replicated the physiological conditions. Hydrogels with/without MSs and TGF-β1 were highly cytocompatible. MSCs in ECM-derived hydrogel containing TGF-β1/MSs showed comparable chondrogenic gene expression levels as those hydrogels with TGF-β1 added in culture media or those without TGF-β1. However, constructs with TGF-β1 directly added within the hydrogel had inferior properties under unloaded conditions. The ECM-derived hydrogel group including TGF-β1/MSs under loading circumstances formed better cartilage matrix in an ex vivo osteochondral defect than control settings. This study demonstrates that controlled local delivery of TGF-β1 using MSs and mechanical loading is essential for neocartilage formation by MSCs and that further optimization is needed to prevent MSC differentiation towards hypertrophy.