Differentiation Of Human Chondrocytes Research Articles

Precipitant induced porosity augmentation of polystyrene preserves the chondrogenicity of human chondrocytes.

Cells constantly sense and receive chemical and physical signals from neighboring cells, interstitial fluid, and extracellular matrix, which they integrate and translate into intracellular responses. Thus, the nature of the surface on which cells are cultured in vitro plays an important role for cell adhesion, proliferation, and differentiation. Autologs chondrocyte implantation is considered the treatment of choice for larger cartilage defects in the knee. To obtain a sufficient number of chondrocytes for implantation multiple passaging is often needed, which raises concerns about the changes in the chondrogenic phenotype. In the present study, we analyzed the effect at cellular and molecular level of precipitant induced porosity augmentation (PIPA) of polystyrene surfaces on proliferation and differentiation of human chondrocytes. Human chondrocytes were isolated from healthy patients undergoing anterior cruciate ligament reconstruction and cultured on PIPA modified polystyrene surfaces. Microscopical analysis revealed topographically arranged porosity with micron pores and nanometer pits. Chondrocytes cultured on PIPA surfaces revealed no difference in cell viability and proliferation, but gene- and protein expressions of collagen type II were pronounced in the first passage of chondrocytes when compared to chondrocytes cultured on control surfaces. Additionally, an analysis of 40 kinases revealed that chondrocytes expanded on PIPA caused upregulated PI3K/mTOR pathway activation and inhibition of mTORC1 resulted in reduced sGAG synthesis. These findings indicate that PIPA modified polystyrene preserved the chondrogenicity of expanded human chondrocytes at gene and protein levels, which clinically may be attractive for the next generation of cell-culture surfaces for ex vivo cell growth. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 3073-3081, 2016.

Untersuchung der Toxizität von Polyvinyl-Pyrrolidon-Jod an fibroblastären Zellen (BALB-3T3) und primären humanen Knorpelzellen

Povidone-iodine (polyvinyl-pyrrolidone-iodine complex, PVP-iodine, CAS 25655-41-8) is a commonly used antiseptic because of its broad spectrum of antimicrobial effect and its comparatively low allergic risk. It is also used for open joint lavage. Animal and organ culture studies provide controversial results about the risk of cartilage damage due to povidone-iodine. There is a paucity of in vitro study data concerning the effect of povidone-iodine on chondrocyte cultures are still missing. The aim of this study was therefore to investigate the effect of different concentrations and exposition times of povidone-iodine on cell growth and differentiation of human chondrocytes. Using of a vitality test (MTT) and a proliferation assay (BrdU) in the fibroblast-like cell line BALB3T3, suitable concentrations and incubation times were identified to investigate the influence of povidone-iodine on proteoglycan synthesis and DNA synthesis of primary human chondrocytes. Concentrations of up to 1% povidone-iodine had no significant effect on proteoglycan and DNA synthesis of chondrocytes after incubation for 30 min. An incubation time of 24 h did not inhibit DNA- and proteoglycan synthesis, until a concentration of 0.2% povidone-iodine was used. DNA synthesis rate was impaired after 10 min incubation with 0.2% and fully inhibited with 1% povidone iodine. BALB3T3 reacted more sensitively than chondrocytes. Vitality and proliferation rate were fully inhibited at a concentration of 0.5% after the same exposition time. However, cells recovered 24 h after 30 min incubation with 0.5% povidone-iodine. After incubation with 5% povidone iodine cells did not recover. From the results it can be concluded that low concentrations of povidone-iodine (< 1%) and short incubation times (< 30 min) have no damaging influence on chondrocytes. Previous studies have reported the antimicrobial effectiveness of low concentrations of povidone-iodine on the reduction of tissue damage by microorganisms. Data from previus studies and the current findings from this investigation support the clinical use of povidone-iodine at low concentrations and short incubation times for antiseptic treatment of cartilage tissues.

Bone and calcium update; bone research update. Molecular mechanisms regulating chondrocyte differentiation and hypertrophy

Chondrocyte differentiation process is composed of multiple steps. During the process, hypertrophy of chondrocyte is controlled by various factors including Indian hedgehog (Ihh) and parathyroid hormone related peptide (PTHrP) . PTHrP signals regulate HDAC4-MEF2C axis in chondrocyte. Recently, several co-factors have been found to interact with Sox9. Function of chondrocyte-specific microRNA has been determined. Several types of Cre transgenic mice are available to express Cre at various steps during chondrocyte differentiation. Using these mice, gene functions at specific steps of chondrocyte differentiation are analyzed by generating conditional knockout mice and conditional transgenic mice. It may be possible in future to induce chondrocytes from skin fibroblasts of patients with genetic cartilage diseases by using iPS cell technology, and to analyze molecular mechanism that control differentiation of human chondrocytes.

In vitro culture of human chondrocytes (1): A novel enhancement action of ferrous sulfate on the differentiation of human chondrocytes.

Chondrogenic differentiation of mesenchymal cells is generally thought to be initiated by the inductive action of specific growth factors and depends on intimate cell-cell interactions. The aim of our investigation was to characterize the influences of basic fibroblast growth factor (bFGF) and ferroussulfate (FeSO(4)) on proliferation and differentiation of human articular chondrocytes (HAC). This is the first report of the effects of FeSO(4) on chondrogenesis of HAC. Multiplied chondrocytes of hip and shoulder joints were cultured in chondrocyte growth medium supplemented with bFGF, FeSO(4), or both bFGF + FeSO(4) for4weeks. A 20 mul aliquot of a cell suspension containing2 x 10(7) cells ml(-1) was delivered onto each well of 24-well tissue culture plates. Cells cultured with the growth medium only was used as a control. Alamar blue and alcian blue staining were done to determine the chondrocyte proliferation and differentiation, respectively, after 4 weeks. The samples exposed to bFGF, FeSO(4), and combination of both indicated sufficient cell proliferation similar to the control level. Differentiations of the HAC exposed to bFGF, FeSO(4),and bFGF + FeSO(4) were 1.2-, 2.0-, and 2.2-fold of the control, respectively. Therefore, chondrocyte differentiation was significantly enhanced by the addition of FeSO(4) andbFGF + FeSO(4). The combined effects of bFGF and FeSO(4) were additive, rather than synergistic. These results suggest that treatment with ferrous sulfate alone or in combination with basic fibroblast growth factor etc, is a powerful tool to promote the differentiation of HAC for the clinical application.