Cocultures of Adult and Juvenile Chondrocytes Compared With Adult and Juvenile Chondral Fragments

Abstract

Background The use of allogenic juvenile chondrocytes or autologous chondral fragments has shown promising laboratory results for the repair of chondral lesions. Hypothesis/Purpose The purpose of the study was to evaluate in vitro the extracellular matrix production of mixed adult/juvenile cultures of both chondrocytes (part 1) and minced cartilage fragments (part 2). The authors hypothesized that juvenile chondrocytes would not affect matrix production when mixed with adult chondrocytes or cartilage fragments. Study design Controlled laboratory study. Methods Cartilage sources consisted of three adult and three juvenile (human) donors. In part 1, per each donor, juvenile chondrocytes were mixed with adult chondrocytes in five different proportions: 100, 50, 25, 12.5 and 0 %. Three-dimensional cultures in low melt agarose were performed. At 6 weeks, biochemical and histological analyses were performed. In part 2, isolated adult, isolated juvenile, and mixed three-dimensional cultures (1:1) were performed with chondral fragments (<1mm), both with low melt agarose and a hyaluronic acid scaffold. At 2 and 6 weeks, cultures were evaluated with biochemical and histological analyses. Results Part 1: biochemical and histological analyses showed that isolated juvenile cultures performed significantly better than mixed and isolated adult cultures. No significant differences were noted between mixed cultures (1:1) and isolated adult cultures. Part 2: biochemical and histological results at 6 weeks showed that mixed cartilage fragment cultures performed better than isolated adult cultures in terms of PG/DNA ratio (p=0.014), percentage of safranin-O positive cells (p=0.012), Bern score (p=0.001), and Collagen type II. No statistical difference was noted between juvenile and mixed cultures. Conclusion Extracellular matrix production of juvenile chondrocytes is inhibited by adult chondrocytes. The addition of juvenile cartilage fragments to adult fragments improves matrix production, with a positive interaction between the two sources. Clinical relevance Even if the underlying mechanisms are still unknown, this study describes the behavior of juvenile/adult co-cultures using both chondrocytes and cartilage fragments, with potential for new research and clinical applications.

Autologous cartilage fragments in a composite scaffold for one stage osteochondral repair in a goat model

“…This neoformed tissue was mostly originating from the migrated chondrocytes and showed features similar to those of articular cartilage, such as the overall predominance of collagen type II staining. These in vitro results are consistent with two previously published studies by Bonasia et al (2011), in which adult and juvenile chondral fragments were cultured on a hyaluronic acid scaffold, and Lu et al (2006). In the latter, human and bovine cartilage fragments were used both in explant cultures and in a heterotopic implant in SCID mice, after being seeded in scaffolds made of polyglycolide/ non-woven felt or polyglycolide/polycaprolactone foam reinforced with polydiaxanone mesh, with a coating of fibrin glue.…”

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