Pronounced biomaterial dependency in cartilage regeneration using nonexpanded compared with expanded chondrocytes

We aimed to investigate freshly isolated compared with culture-expanded chondrocytes with respect to early regenerative response, cytokine production and cartilage formation in response to four commonly used biomaterials.

Chondrocytes were both directly and after expansion to passage 2, incorporated into four biomaterials: Polyactive™, Beriplast®, HyStem® and a type II collagen gel. Early cartilage matrix gene expression, cytokine production and glycosaminoglycan (GAG) and DNA content in response to these biomaterials were evaluated.

HyStem induced more GAG production, compared with all other biomaterials (p ≤ 0.001). Nonexpanded cells did not always produce more GAGs than expanded chondrocytes, as this was biomaterial-dependent. Cytokine production and early gene expression were not predictive for final regeneration.

For chondrocyte-based cartilage treatments, the biomaterial best supporting cartilage matrix production will depend on the chondrocyte differentiation state and cannot be predicted from early gene expression or cytokine profile.