Bioengineered chondrocyte sheets may be potentially useful for the treatment of partial thickness defects of articular cartilage.
ABSTRACT Some treatments for full thickness defects of articular cartilage, such as cultured chondrocyte transplantation, have already been done. However, to overcome osteoarthritis, we must further study the partial thickness defect of articular cartilage. It is much more difficult to repair a partial thickness defect because few repairing cells can address such injured sites. We herein show that bioengineered layered chondrocyte sheets using temperature-responsive culture dishes may be a potentially useful treatment for partial thickness defects. We evaluated the property of these sheets using real-time PCR and histological findings, and allografted these sheets to evaluate the effect of treatment using a rabbit partial model. In conclusion, layered chondrocyte sheets were able to maintain the cartilageous phenotype, and could be attached to the sites of cartilage damage which acted as a barrier to prevent a loss of proteoglycan from these sites and to protect them from catabolic factors in the joint.
- SourceAvailable from: nih.gov[show abstract] [hide abstract]
ABSTRACT: Expression of the chitinase 3-like protein HC-gp39 (human cartilage glycoprotein 39) is associated with conditions of increased matrix turnover and tissue remodelling. High levels of this protein have been found in sera and synovial fluids of patients with inflammatory and degenerative arthritis. In order to assess the role of HC-gp39 in matrix degradation induced by inflammatory cytokines, we have examined its effect on the responses of connective tissue cells to TNF-alpha (tumour necrosis factor-alpha) and IL-1 (interleukin-1) with respect to activation of signalling pathways and production of MMPs (matrix metalloproteases) and chemokines. Stimulation of human skin fibroblasts or articular chondrocytes with IL-1 or TNF-alpha in the presence of HC-gp39 resulted in a marked reduction of both p38 mitogen-activated protein kinase and stress-activated protein kinase/Jun N-terminal kinase phosphorylation, whereas nuclear translocation of nuclear factor kappaB proceeded unimpeded. HC-gp39 suppressed the cytokine-induced secretion of MMP1, MMP3 and MMP13, as well as secretion of the chemokine IL-8. The suppressive effects of HC-gp39 were dependent on phosphoinositide 3-kinase activity, and treatment of cells with HC-gp39 resulted in AKT-mediated serine/threonine phosphorylation of apoptosis signal-regulating kinase 1. This process could therefore be responsible for the down-regulation of cytokine signalling by HC-gp39. These results suggest a physiological role for HC-gp39 in limiting the catabolic effects of inflammatory cytokines.Biochemical Journal 07/2004; 380(Pt 3):651-9. · 4.65 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Although cardiac myocytes adherent to tissue culture polystyrene (TCPS) dishes retain the spontaneous beating, the pulsatile amplitude is highly limited compared to that in vivo. One of the main reasons for the limited pulsation may be the interface between the cells and the TCPS surfaces. Release of these cells from rigid TCPS surfaces may augment their pulsatile amplitude. With this perspective, we have developed a novel cell manipulation technique to detach cultured cardiac myocytes from rigid surfaces and to rescue higher pulsatile amplitude of the cells using temperature-responsive culture dishes and discuss the possibility of improving this heart tissue model. Primary cardiac myocytes were cultured on the slightly hydrophobic dish surfaces grafted with a temperature-responsive polymer, poly(N-isopropylacrylamide). Cells adhered and proliferated, forming confluent cardiac myocyte sheets in a fashion similar to those on ungrafted TCPS dishes. Decrease in culture temperature resulted in surface change of the polymer from slight hydrophobic to highly hydrophilic due to extensive hydration of the grafted polymer on the dishes. This results in release of cardiac myocyte sheets from the dishes without enzymatic or EDTA treatment. When no support was used, the detached cardiac myocyte sheets shrank to one-tenth size, which ceased their pulsation. When chitin membranes were used to support the confluent sheets to prevent cell shrinkage, the detached cell sheets could be transferred and readily adhered onto another virgin TCPS dishes. These transferred cell sheets preserved the similar cell morphology and pulsation to those before the detachment. When polyethylene meshes were used to support cell sheet transfer, detached cardiac myocyte sheets partially attached to the mesh threads. Then, the constructs were inverted and placed in another culture dish to prevent direct association to dish surfaces. Moreover, the cardiac myocyte sheets were reorganized to heart tissue-like structures by the unisotropic contraction orientated by the mesh threads, and the pulsatile amplitude increased more than 10 times higher. This technique would bring about new insight in tissue engineering as well as cultured heart model.Tissue Engineering 05/2001; 7(2):141-51. · 4.07 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Recent progress in cell transplantation therapy to repair impaired hearts has encouraged further attempts to bioengineer 3-dimensional (3-D) heart tissue from cultured cardiomyocytes. Cardiac tissue engineering is currently pursued utilizing conventional technology to fabricate 3-D biodegradable scaffolds as a temporary extracellular matrix. By contrast, new methods are now described to fabricate pulsatile cardiac grafts using new technology that layers cell sheets 3-dimensionally. We apply novel cell culture surfaces grafted with temperature-responsive polymer, poly(N-isopropylacrylamide) (PIPAAm), from which confluent cells detach as a cell sheet simply by reducing temperature without any enzymatic treatments. Neonatal rat cardiomyocyte sheets detached from PIPAAm-grafted surfaces were overlaid to construct cardiac grafts. Layered cell sheets began to pulse simultaneously and morphological communication via connexin43 was established between the sheets. When 4 sheets were layered, engineered constructs were macroscopically observed to pulse spontaneously. In vivo, layered cardiomyocyte sheets were transplanted into subcutaneous tissues of nude rats. Three weeks after transplantation, surface electrograms originating from transplanted grafts were detected and spontaneous beating was macroscopically observed. Histological studies showed characteristic structures of heart tissue and multiple neovascularization within contractile tissues. Constructs transplanted into 3-week-old rats exhibited more cardiomyocyte hypertrophy and less connective tissue than those placed into 8-week-old rats. Long-term survival of pulsatile cardiac grafts was confirmed up to 12 weeks. These results demonstrate that electrically communicative pulsatile 3-D cardiac constructs were achieved both in vitro and in vivo by layering cardiomyocyte sheets. Cardiac tissue engineering based on this technology may prove useful for heart model fabrication and cardiovascular tissue repair. The full text of this article is available at http://www.circresaha.org.Circulation Research 03/2002; 90(3):e40. · 11.86 Impact Factor