Summary

Biomechanical evaluation of tissue-engineered cartilage restoration and cell therapy treatments in a GMP translational large animal model

Abstract

Introduction

The chondral lesion and osteoarthritis are conditions associated with an economic burden, since if left untreated may cause changes in the biomechanics of the joint and result in several injuries considered highly disabling to the individual. Mesenchymal Stromal Cells (MSCs) have the immunomodulatory capacity and paracrine signaling that are useful for tissue bioengineering to treat bone and cartilage injuries. The articular cartilage is a viscoelastic material that can undergone structural and compositional changes; therefore, it is important to assess the physical properties of the tissue through mechanical evaluation. The differential of this study is that the cell culture process was carried out under Good Manufacturing Practices (GMP) conditions for use in humans. Objective: This study aims to describe biomechanical analysis for cartilage restoration by tissue engineering and cell therapy treatments in a GMP translational large animal model Methods: A controlled experimental study in fourteen Brazilian miniature pigs was performed, using scaffold-free Tissue Engineering Construct (TEC) from dental pulp and synovial MSCs with 6 months follow-up. To compare the cartilage with and without TEC, three stress-strain cycles were performed in the indentation test, followed by maximum compression, as well as Finite Element (FE) model using ANSYS R17.2 to simulate the osteochondral block and characterize its properties Results: Indentation and maximum compression tests assessed the properties of the solid matrix and mechanical proprieties of the tissue repair in control and treatment groups. The indentation response showed the hysteresis phenomenon evidencing the viscoelastic property of the articular cartilage. The Young Modulus (YM) determined at 5% strain were 0.72 ± 0.47 and 1.23 ± 0.82 for the control and treatment groups, respectively, with statistical significance (p < 0.05). The FE analysis showed the force distribution in the osteochondral block Conclusion: The proposed method allowed feasible and capable evaluation of the physical properties of the articular cartilage restoration. A higher YM value in the treated group might indicate superior repair. The FE model allowed for better visualization of the structure when undergoing compression.