Dedifferentiated Human Articular Chondrocytes Redifferentiate to a Cartilage-Like Tissue Phenotype in a Poly(ε-Caprolactone)/Self-Assembling Peptide Composite Scaffold.

Lourdes Recha-Sancho,Farshid Guilak,Jordi Abellà,Carlos Semino,Franklin Moutos

doi:10.3390/ma9060472

Abstract

Adult articular cartilage has a limited capacity for growth and regeneration and, with injury, new cellular or biomaterial-based therapeutic platforms are required to promote repair. Tissue engineering aims to produce cartilage-like tissues that recreate the complex mechanical and biological properties found in vivo. In this study, a unique composite scaffold was developed by infiltrating a three-dimensional (3D) woven microfiber poly (ε-caprolactone) (PCL) scaffold with the RAD16-I self-assembling nanofibers to obtain multi-scale functional and biomimetic tissue-engineered constructs. The scaffold was seeded with expanded dedifferentiated human articular chondrocytes and cultured for four weeks in control and chondrogenic growth conditions. The composite constructs were compared to control constructs obtained by culturing cells with 3D woven PCL scaffolds or RAD16-I independently. High viability and homogeneous cell distribution were observed in all three scaffolds used during the term of the culture. Moreover, gene and protein expression profiles revealed that chondrogenic markers were favored in the presence of RAD16-I peptide (PCL/RAD composite or alone) under chondrogenic induction conditions. Further, constructs displayed positive staining for toluidine blue, indicating the presence of synthesized proteoglycans. Finally, mechanical testing showed that constructs containing the PCL scaffold maintained the initial shape and viscoelastic behavior throughout the culture period, while constructs with RAD16-I scaffold alone contracted during culture time into a stiffer and compacted structure. Altogether, these results suggest that this new composite scaffold provides important mechanical requirements for a cartilage replacement, while providing a biomimetic microenvironment to re-establish the chondrogenic phenotype of human expanded articular chondrocytes.

Highlights

Articular cartilage is an avascular tissue with a highly specialized extracellular matrix (ECM)architecture and composition that allows it to withstand the mechanical requirements of the diarthrodial joint [1]
As a previous step a simple wettability assay was performed on PCL scaffold measuring the contact angle formed with water (Figure 1A) and RAD16-I at 0.5% (Figure 1B)
The fiber architecture of the woven PCL scaffolds and PCL/RAD composite scaffold were assessed by scanning electron microscope (SEM) (Figure 1C–F)

Summary

Introduction

Architecture and composition that allows it to withstand the mechanical requirements of the diarthrodial joint [1]. The principal function of cartilage is to withstand mechanical loads while allowing low friction movements of joints over millions of cycles of loading [2]. Chondrocytes are the only resident cells in articular cartilage and, are responsible for synthesizing and maintaining the complex ECM [3]. Cartilage shows little or no capacity for self-repair, and cartilage defects generated by trauma or injury can result in long-term pain and loss of joint function. New strategies for cartilage repair are required and tissue engineering has emerged as a potential source to generate cartilage-like structures through the use of cells and biomaterials [6,7]

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Conclusion