A model for studying human articular cartilage integration in vitro

Abstract

One of the major obstacles hindering cartilage repair is the integration of the reparative cartilage with the recipient cartilage. The purpose of this study was to develop an in vitro model that can be conveniently applied to simulate and improve the integration of tissue engineered cartilage with native articular cartilage. This model, a cartilage integration construct, consists of a cartilage explant and isolated chondrocytes. The explant was anchored to agarose gel on a culture plate as agarose gelation at 4 degrees C to seal the gap between the bottom of the explant and culture plate surface. Isolated chondrocytes were added and confined in the defect created in the center of the explant. After 4 weeks of culture, neocartilage containing proteoglycans and type II collagen was formed. Minimal integration occurred between the neocartilage and the cartilage explant, resembling the failure of cartilage integration manifested in experimental and clinical cartilage repair. In this model, agarose gel anchors the explant onto culture plate by altering temperatures and effectively prevents "leakage" of the isolated chondrocytes from the defect of the explant. This model provides a convenient simulation of the cartilage integration process in vitro and has applications in studies of cartilage integration and cartilage tissue engineering.

Chondrocyte Migration Affects Tissue-Engineered Cartilage Integration by Activating the Signal Transduction Pathways Involving Src, PLCγ1, and ERK1/2

“…The reason that might explain the fact was that the cell density in this model was well above the previously determined high density, for example, 4 · 10 5 /cm 2 , which retained the chondrocyte phenotype. 13 Additionally, Src, PLCg1, or ERK1/2 pathways had no relationship with chondrocyte apoptosis or inflammation in our in vitro integration model.…”

“…13 Articular cartilage was aseptically harvested from the femoropatellar joints of young pigs (7 months old). Cartilage rings (Ø 6 · 2 mm thickness) with a 3-mm inner hole were created as cartilage explants.…”

A novel in vitro bovine cartilage punch model for assessing the regeneration of focal cartilage defects with biocompatible bacterial nanocellulose

“…This was underlined by: 1) smooth adaptation of the BNC to the defect edges in the 'host' cartilage cylinder, likely based on the enormous water binding and swelling capacity of BNC and generally considered a prerequisite for successful cartilage regeneration [86,87]; 2) emigration/seeding of the BNC with resident, phenotypically stable chondrocytes without any signs of toxicity, indicating a high biocompatibility of the material; 3) substantial de novo deposition of cartilage-specific matrix onto and into the BNC scaffold, contributing to the sealing of the defect; and 4) initial signs of lateral integration/bonding of the BNC (in)to the edges of the cartilage defect, indicated by the so-called 'cartilage flow phenomenon' and also regarded as pivotal for defect regeneration in vivo . These findings are in agreement with the known biocompatibility of BNC as a scaffold material in general [11,12,88-90] and, in particular, its capacity to support the growth of vital, metabolically active chondrocytes [20].…”

Repair of Cartilage Defects in Arthritic Tissue with Differentiated Human Embryonic Stem Cells

“…Furthermore, unlike more regenerative systems, such as skin and bone in which new tissues integrate with surrounding old tissue, grafted and newly regenerated cartilage does not bond well with preexisting mature cartilage. [3][4][5][6] Surgical attempts to generate tissue resembling native cartilage have included microfracture, matrix scaffolds, and osteochondral grafting. 7 Cell-replacement approaches, such as autologous chondrocyte transplantation are attractive for promoting repair and regeneration in lesions of cartilage.…”