Scaffold-free approach produces neocartilage tissue of similar quality as the use of HyStem\u2122 and Hydromatrix\u2122 scaffolds

Janne H Ylärinne,Chengjuan Qu,Mikko J Lammi

doi:10.1007/s10856-017-5870-2

Abstract

Numerous biomaterials are being considered for cartilage tissue engineering, while scaffold-free systems have also been introduced. Thus, it is important to know do the scaffolds improve the formation of manufactured neocartilages. This study compares scaffold-free cultures to two scaffold-containing ones. Six million bovine primary chondrocytes were embedded in HyStem™ or HydroMatrix™ scaffolds, or suspended in scaffold-free chondrocyte culture medium, and then loaded into agarose gel supported culture well pockets. Neocartilages were grown in the presence of hypertonic high glucose DMEM medium for up to 6 weeks. By the end of culture periods, the formed tissues were analyzed by histological staining for proteoglycans (PGs) and type II collagen, gene expression measurements of aggrecan, Sox9, procollagen α1(II), and procollagen α2(I) were performed using quantitative RT-PCR, and analyses of PG contents and structure were conducted by spectrophotometric and agarose gel electrophoretic methods. Histological stainings showed that the PGs and type II collagen were abundantly present in both the scaffold-free and the scaffold-containing tissues. The PG content gradually increased following the culture period. However, the mRNA expression levels of the cartilage-specific genes of aggrecan, procollagen α1(II) and Sox9 gradually decreased following culture period, while procollagen α2(I) levels increased. After 6-week-cultivations, the PG concentrations in neocartilage tissues manufactured with HyStem™ or HydroMatrix™ scaffolds, and in scaffold-free agarose gel-supported cell cultures, were similar to native cartilage. No obvious benefits could be seen on the extracellular matrix assembly in HyStem™ or HydroMatrix™ scaffolds cultures.Graphical abstract

Highlights

Today, tissue engineering is considered to offer great possibilities for the field of regenerative medicine, and researchers working on various disciplines of the regenerative medicine show great interest on it worldwide
The day, six million chondrocytes were seeded into the agarose gel wells in HyStemTM or HydroMatrixTM scaffolds, or as a control without the scaffold
The control and the HyStemTM samples were discshaped and smoothest on the surface, whereas the tissues grown in the HydroMatrixTM scaffolds were more often irregularly shaped, and their surfaces were not as smooth as in the control ones

Summary

Introduction

Tissue engineering is considered to offer great possibilities for the field of regenerative medicine, and researchers working on various disciplines of the regenerative medicine show great interest on it worldwide. The principle of the tissue engineering is to regenerate neotissues by using cells, biomaterials and/or signaling 59 Page 2 of 8. Articular cartilage is basically quite simple tissue in its structure and function. It seems to be one of the most ideal candidates for the tissue engineering approaches [3]. There are no standardized methods available at present to reproducibly succeed in the regeneration of a perfect functional articular cartilage in vitro. The problem lies in the ability to create a correct fine structure of the tissue extracellular matrix. It is relatively easy to grow a cartilage-like tissue in laboratory conditions, but usually the tissues lacks a zonal organization and resilience of the true articular cartilage [4, 5]

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