Effects of extracellular matrix on the morphology and behaviour of rabbit auricular chondrocytes in culture

A preclinical evaluation of an autologous living hyaline-like cartilaginous graft for articular cartilage repair: a pilot study

In this pilot study, an autologous synthetic scaffold-free construct with hyaline quality, termed living hyaline cartilaginous graft (LhCG), was applied for treating cartilage lesions. Implantation of autologous LhCG was done at load-bearing regions of the knees in skeletally mature mini-pigs for 6 months. Over the course of this study, significant radiographical improvement in LhCG treated sites was observed via magnetic resonance imaging. Furthermore, macroscopic repair was effected by LhCG at endpoint. Microscopic inspection revealed that LhCG engraftment restored cartilage thickness, promoted integration with surrounding native cartilage, produced abundant cartilage-specific matrix molecules, and re-established an intact superficial tangential zone. Importantly, the repair efficacy of LhCG was quantitatively shown to be comparable to native, unaffected cartilage in terms of biochemical composition and biomechanical properties. There were no complications related to the donor site of cartilage biopsy. Collectively, these results imply that LhCG engraftment may be a viable approach for articular cartilage repair.

Effects of intermittent hydrostatic pressure magnitude on the chondrogenesis of MSCs without biochemical agents under 3D co-culture

Without using biochemical agents, in this study, we sought to investigate the potential of controlling the differentiation of mesenchymal stem cells (MSCs) into a specific cell type through the use of 3D co-culturing and mechanical stimuli. MSCs and primary cultured chondrocytes were separately encapsulated into alginate beads, and the two types of beads were separated by a membrane. For the investigation a computer-controllable bioreactor was designed and used to engage intermittent hydrostatic pressure (IHP). Five different magnitudes (0.20, 0.10, 0.05, 0.02 MPa and no stimulation) of IHP were applied. The stimulation pattern was the same for all groups: 2 h/day for 7 days starting at 24 h after seeding; 2 and 15 min cycles of stimulating and resting, respectively. Biochemical (DNA and GAG contents), histological (Alcian blue), and RT-PCR (Col II, SOX9, AGC) analyses were performed on days 1, 5, 10, and 20. The results from these analyses showed that stimulation with higher magnitudes of IHP (≥0.10 MPa) were more effective on the proliferation and differentiation of co-cultured MSCs. Together, these data demonstrate the potential of using mechanical stimulation and co-culturing for the proliferation and differentiation of MSCs, even without biochemical agents.

Functionalization of dynamic culture surfaces with a cartilage extracellular matrix extract enhances chondrocyte phenotype against dedifferentiation

Culture on silicone rubber surfaces has been shown to partially overcome the chondrocyte dedifferentiation characteristic of standard culture on rigid polystyrene. These methods typically involve functionalization of culture surfaces with proteins. Collagen type I is often used, but more cartilage-specific proteins may be more appropriate for chondrocytes. To explore this hypothesis, a twofold experimental design was applied. First, chondrocytes were cultured in rigid Petri dishes coated with silicone rubber ("static silicone" or SS culture) functionalized with either cartilage extracellular matrix (ECM) extract or collagen type I. Second, chondrocytes were cultured on monotonically expanded high extension silicone rubber dishes ("continuous expansion" or CE culture) functionalized with ECM extract and compared to cells grown in SS culture. There were no differential effects of surface functionalization with the ECM extract vs. collagen type I on chondrocyte morphology, viability, proliferation or apoptosis in SS culture. However, chondrocyte growth on the ECM extract was associated with significantly reduced collagen types I and X gene expression and significantly increased glycosaminoglycan (GAG) secretion. After 3 passages (P3) on ECM-coated SS culture, chondrocyte phenotype and GAG secretion was enhanced compared to cells passaged on collagen type I. Pellet cultures from P3 SS culture displayed enhanced collagen type II content when ECM extract was used for functionalization rather than collagen type I. In CE culture with ECM functionalization, chondrocyte dedifferentiation was significantly inhibited vs. SS cultures, as evidenced by both gene expression and pellet cultures. Functionalization of extendable culture surfaces with cartilage ECM extract therefore supports enhanced preservation of chondrocyte phenotype.

Maintenance of cartilaginous gene expression on extracellular matrix derived from serially passaged chondrocytes during in vitro chondrocyte expansion

The loss of cartilaginous phenotype during in vitro expansion culture of chondrocytes is a major barrier for the application of cartilage tissue engineering. The use of matrices mimicking the in vivo extracellular matrix (ECM) microenvironment is anticipated to be an efficient method to suppress chondrocyte phenotype loss. In this study, we developed several types of ECM derived from serially passaged chondrocytes for use as cell-culture substrata and compared their effects on chondrocyte functions. Primary bovine chondrocytes and serially passaged chondrocytes (at passages 2 and 6) were cultured on tissue-culture polystyrene. After culture, the cellular components were selectively removed from the ECM deposited by the cells. The remaining ECM proteins were used as cell-culture substrata. The composition of the deposited ECM depended on the culture stage of the serially passaged chondrocytes used for the ECM production. The deposited ECM supported the adhesion and proliferation of chondrocytes. The effects of the ECM on the chondrocyte dedifferentiation during in vitro passage culture differed dramatically depending on the phenotype of the chondrocytes used to produce the ECM. The primary chondrocyte-derived ECM delayed the chondrocyte dedifferentiation during in vitro passage culture and is a good candidate for chondrocyte subculture for tissue engineering.

Role of poly-L-lysine-coated plates and fetal calf serum concentration in sheep chondroprogenitor cell culturing

Conventional methods for differentiation of chondroprogenitor cells on plastic plates face several problems that hinder the application of this method for the treatment of chondrogenic injury. This work focused on the effect of poly-L-lysine (PLL)-coated plastic surfaces and fetal calf serum concentration on the chondroprogenitor cells. In the present study, cartilage was isolated from the articular cartilages of sheep and the cells were seeded on PLL-coated plates in various serum concentrations. Histochemical analysis was used to determine chondrogenic differentiation of the cells. According to our results, the cells formed three-dimensional masses and chondrogenic cells. In the present investigation, the best culture conditions for maximum proliferation of isolated cells were examined. Taken together, the results indicated that PLL may have some effect on the adhesive properties of chondroprogenitor cells and could be used for cartilage engineering.