Research progress on osteochondral tissue engineering / 生物医学工程学杂志

Osteochondral defects is a common clinical joint disease. The complexity of cartilage-bone interface and the poor self-repair capacity of cartilage are both reasons for current relatively limited clinical treatments. The introduction of tissue engineering provides a new treatment method for osteochondral repair. This paper reviews three main elements of cartilage-bone tissue engineering: seed cell source and culture method, cytokines regulation and synergistic effect, and scaffold components and type. We mainly focused on current status quo and future progress of cartilage-bone repair scaffolds. This paper provides some reference for the further development of osteochondral tissue engineering.

Demineralized cancellous bone seeded with allogeneic chondrocytes for repairing articular osteochondral defects in rabbits / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effect of demineralized cancellous bone (DCB) seeded with allogeneic chondrocytes for repairing articular osteochondral defects in rabbits.</p><p><b>METHODS</b>Articular chondrocytes were isolated from a 1-month-old male New Zealand rabbit for primary culture. The passage 1 chondrocytes were seeded onto prepared rabbit DCB scaffold to construct tissue-engineered cartilage and cultured for 2 weeks. Full-thickness articular osteochondral defects (3 mm both in diameter and depth) were created on both sides of the femoral medial condyles in 30 New Zealand white rabbits (age 4- 5 months). In 20 of the rabbits, the defects were filled with the tissue-engineered cartilage on the right side (group A) and with DCB only on the left side (group B); the remaining 10 rabbits did not receive any implantation in the defects to serve as the control (group C). At 1, 3, and 6 months after the implantation, tissue samples were collected from the defects for macroscopic observation and histological examination with Toluidine blue (TB) and collagen type Ⅱ staining. The effect of defect repair using the tissue-engineered cartilage was assessed at 6 months based on the histological scores.</p><p><b>RESULTS</b>The prepared DCB had a spongy 3D structure with open and interconnected micropores of various sizes and showed good plasticity and mechanical strength. DCB began to degrade within 1 month after implantation and was totally absorbed at 3 months. At 6 months after implantation, the defects filled with the chondrocyte-seeded DCB were repaired mainly by hyaline-like cartilage tissues, which were well integrated to the adjacent cartilage without clear boundaries and difficult to recognize. The chondrocytes were located in the lacunate and arranged in vertical columns in the deep repaired tissue, where matrix proteoglycans and collagen type Ⅱ were distributed homogeneously close to the normal cartilage. The subchondral bone plate was reconstructed completely. The defects implanted with DCB only were filled with fibrocartilage tissue, as compared with fibrous tissue in the control defects. The histological scores in group A were significantly superior to those in group B and C ( < 0.05), but the scores for subchondral bone plate reconstruction were comparable between groups A and B at 6 months.</p><p><b>CONCLUSIONS</b>DCB is a good scaffold material for preparing tissue-engineered cartilage, and chondrocyte- seeded DCB can repair articular osteochondral defects by inducing the generation of hayline-like cartilage.</p>

The Effects of Substrates and Hydrostatic Pressure on Differentiation of Mesenchymal Stem Cell / 대한정형외과연구학회지

PURPOSE: This study investigated the potential of dual differentiation of stem cells into osteo- and chodrogenesis depending on scaffold type even in the same environment. MATERIALS AND METHODS: For the part of the cartilage tissue section, MSCs were suspended in alginate solution and bead droplets were made using 23G syringe. For the bone tissue section, PCL/HA scaffolds were made using the bio-plotting system followed by seeding mesenchymal stem cells (MSCs) onto the scaffolds. Scaffolds with MSCs were cultured in cocktail media containing osteogenic and chondrogenic growth factors for up to 21 days. To provide mechanical environments which articular cartilage experiences in-vivo, intermittent hydrostatic pressure (IHP) was engaged. Various cellular responses were assessed: the quantitative analysis of DNA contents, GAG contents, ALP activities and immunofluorescence. RESULTS: We found that IHP promoted MSCs differentiation into the targeted cell types. That is, MSCs in alginate scaffolds were able to be differentiated into chondrocytes, while those onto PCL/HA scaffolds were able to be differentiated into osteoblasts. CONCLUSION: Depending on the scaffold characteristics MSCs can be differentiated into bone cells or chondrocytes. This technique can provide a cue for the treatment of osteochondral defects utilizing tissue engineering.

The Effects of Substrates and Hydrostatic Pressure on Differentiation of Mesenchymal Stem Cell / 대한정형외과연구학회지

PURPOSE: This study investigated the potential of dual differentiation of stem cells into osteo- and chodrogenesis depending on scaffold type even in the same environment. MATERIALS AND METHODS: For the part of the cartilage tissue section, MSCs were suspended in alginate solution and bead droplets were made using 23G syringe. For the bone tissue section, PCL/HA scaffolds were made using the bio-plotting system followed by seeding mesenchymal stem cells (MSCs) onto the scaffolds. Scaffolds with MSCs were cultured in cocktail media containing osteogenic and chondrogenic growth factors for up to 21 days. To provide mechanical environments which articular cartilage experiences in-vivo, intermittent hydrostatic pressure (IHP) was engaged. Various cellular responses were assessed: the quantitative analysis of DNA contents, GAG contents, ALP activities and immunofluorescence. RESULTS: We found that IHP promoted MSCs differentiation into the targeted cell types. That is, MSCs in alginate scaffolds were able to be differentiated into chondrocytes, while those onto PCL/HA scaffolds were able to be differentiated into osteoblasts. CONCLUSION: Depending on the scaffold characteristics MSCs can be differentiated into bone cells or chondrocytes. This technique can provide a cue for the treatment of osteochondral defects utilizing tissue engineering.

An experimental intraarticular implantation of woven carbon fiber pad into osteochondral defect of the femoral condyle in rabbit

The defects of the articular cartilage structure are not replaced unless the subchondral plate has been breached. However, following the creation of a defect in the subchondral plate, the area is filled in with a fibrous tissue which gradually transforms to hyaline cartilage. The porous nontoxic materials of both biologic and synthetic origin have reportedly been used as matrices for repairing bone and cartilage. Following implantation, carbon fibre, chemically inert and well-tolerated by the body, induces a proliferation of ordered fibrous tissue. We implanted carbon fiber pads in osteochondral defects in rabbits. Those repairs were compared to control holes with no implants. The pads appeared to induce the gross appearance of a restored joint surface, mechanically strong to loading for periods from 2 to 6 weeks. Also, carbon fiber pads promoted the healing of the osteochondral defects in the rabbit femoral condyle, supplying well-organized cartilagenous tissue over repaired subchondral bone. The use of carbon fiber pads as implant material is suggested for the restoration of articular surface in osteoarthritis and osteochondritis dissecans.