Behavior of human articular chondrocytes derived from nonarthritic and osteoarthritic cartilage in a collagen matrix.

The purpose of this study was to evaluate the morphologic and biochemical behavior and activity of human chondrocytes taken from nonarthritic and osteoarthritic cartilage and seeded on a three-dimensional matrix consisting of collagen types I, II, and III. Human articular chondrocytes were isolated from either nonarthritic or osteoarthritic cartilage of elderly subjects, and from nonarthritic cartilage of an adolescent subject, seeded on collagen matrices, and cultured for 12 h, 7 days, and 14 days. Histological analysis, immunohistochemistry, and biochemical assays for glycosaminoglycans (GAGs) and DNA content were performed for cell-seeded and unseeded matrices. Chondrocytes of nonarthritic cartilage revealed a larger number of spherical cells, consistent with a chondrocytic phenotype. The biochemical assay showed a net increase in GAG content in nonarthritic chondrocytes, whereas almost no GAGs were seen in osteoarthritic cells. The DNA results suggest that more osteoarthritic cells than chondrocytes from nonarthritic cartilage attached to the matrix within the first week. Human articular chondrocytes isolated from osteoarthritic cartilage seem to have less bioactivity after expansion and culture in a sponge consisting of type I, II, and III collagen compared with chondrocytes from nonarthritic cartilage.

Characteristics of ovine articular chondrocytes in a three-dimensional matrix consisting of different crosslinked collagen.

The purpose of this study was to evaluate the (ultra-) morphology, biochemical behavior, and activity of ovine chondrocytes seeded on a matrix consisting of three types of collagen (I, II, III) with two different degrees of UV crosslinking. Ovine articular chondrocytes were isolated from stifle joints and seeded on both types of UV-crosslinked collagen matrices, as well as on non-crosslinked sponges, and cultured for 12 h, 7 days, 14 days, and 21 days. Histological analysis, electron microscopy, biochemical assays for glycosaminoglycans, and real-time quantitative PCR for collagens were performed for cell-seeded and unseeded matrices. There was no dramatic difference in the morphology and bioactivity of the cells; however, concerning handling characteristics and integrative stability, both types of crosslinked sponges were superior to non-crosslinked constructs. The results demonstrate that ovine articular chondrocytes express their phenotype in a sponge consisting of collagen; furthermore, because of mechanical reasons, non-crosslinked matrices cannot be recommended for implantation in vivo.

Different behavior of meniscal cells in collagen II/I,III and Hyaff-11 scaffolds in vitro.

The purpose of this study was to evaluate the behavior of ovine meniscal cells seeded on biomaterials made from collagen and hyaluronan, respectively. Ovine meniscal cells were isolated from the medial menisci of stifle joints, expanded in monolayer culture, and seeded on scaffolds made of collagen type II and I/III and a hyaluronan derivative (Hyaff-11). The samples were cultured for 12 h and 7, 14, 21, and 28 days. Histological analysis, electron microscopy, biochemical assays for glycosaminoglycans (GAGs) and DNA, and reverse transcriptase polymerase chain reaction analysis for collagens were performed. The cells attached well to both biomaterials and produced tissue-specific proteins, such as GAG and collagen type I, over a period of 28 days. Differences between the biomaterials were seen with respect to cell distribution, cell morphology, and the dynamics of GAG synthesis. The results show that ovine meniscal cells express their phenotype in both biomaterials. In terms of biology, collagen and hyaluronan are both suitable for tissue engineering in meniscal regeneration. It remains to be determined which scaffold possesses adequate biomechanical properties for successful in vivo application.