Cartilaginous Tissue (cartilaginous + tissue)

Distribution by Scientific Domains

Selected Abstracts

Ultrastructural and histochemical study on gills and skin of the Senegal sole, Solea senegalensis

J. M. Arellano
Summary This study was undertaken to identify the normal ultrastructural features of gills and skin of the Senegal sole, Solea senegalensis, for a comparative measure to morphological alterations caused by environmental stressors such as reduced water quality and diseases. In the Senegal sole skin, four morphologically distinct layers were identified: cuticle, epidermis, dermis and hypodermis. The epidermis was composed of stratified epithelium containing three cellular layers: the outermost or mucosa layer, the middle or fusiform layer and the stratum germinativum or the basal layer. In the mucosa, two mucous cell types were differentiated: type A cells containing several round vesicles of different electron density and type B cells containing mucosomes of uniform electron density. Senegal sole have five pairs of gill arches, each containing two rows of well-developed and compactly organized primary filaments and secondary lamellae. Fingerprint-like microridges were observed on the surface of epithelial cells. The branchial lamellae epithelium consisted of different cell types: pavement, mucous and chloride. Between the chloride cells and the larger pavement cells, accessory cells were observed. Complexes of tight junctions and desmosomes were frequently observed between adjacent chloride and epithelial cells. Neutral mucosubstances and/or glycoconjugates were observed in the epidermis, dermis and hypodermis of S. senegalensis skin. Proteins rich in different amino acids, such as arginine and cysteine, reacted negatively or weakly positive in the epidermis, dermis and hypodermis. In gills, some mucous cells responded weakly positive to periodic acid-Schiff (PAS) reaction but were strongly stained with Alcian Blue at pH 0.5, 1 and 2.5. When Alcian Blue pH 2.5,PAS reaction was performed, most mucous cells were stained blue (carboxylated mucins) and some mucocytes stained purple, indicating a combination of neutral and acid mucins. Proteins rich in cysteine-bound sulphydryl (-SH-) and cystine disulphide (-S-S-) groups were strongly detected in branchial and epidermal mucous cells, whereas lysine, tyrosine and arginine containing proteins showed very weak staining in both epidermal and branchial mucous cells. Protein reactions were strongly positive in the pillar cells, except for those rich in tryptophan, whereas the branchial cartilaginous tissue did not show an important reaction. The performed lipid reactions were negative in goblet and chloride cells. It is concluded from this study that ultrastructural and cytohistochemical features of the Senegal sole skin and gills may serve as control structures in both natural and aquaculture systems to monitor or detect environmental stress responses at the histological level. [source]

Formation of cartilage repair tissue in articular cartilage defects pretreated with microfracture and covered with cell-free polymer-based implants,

Christoph Erggelet
Abstract The aim of our study was to evaluate the mid-term outcome of a cell-free polymer-based cartilage repair approach in a sheep cartilage defect model in comparison to microfracture treatment. Cell-free, freeze-dried implants (chondrotissue®) made of a poly-glycolic acid (PGA) scaffold and hyaluronan were immersed in autologous serum and used for covering microfractured full-thickness articular cartilage defects of the sheep (n,=,4). Defects treated with microfracture only served as controls (n,=,4). Six months after implantation, cartilage implants and controls were analyzed by immunohistochemical staining of type II collagen, histological staining of proteoglycans, and histological scoring. Histological analysis showed the formation of a cartilaginous repair tissue rich in proteoglycans. Histological scoring documented significant improvement of repair tissue formation when the defects were covered with the cell-free implant, compared to controls treated with microfracture. Immunohistochemistry showed that the cell-free implant induced cartilaginous repair tissue and type II collagen. Controls treated with microfracture showed marginal formation of a mixed-type repair tissue consisting of cartilaginous tissue and fibro-cartilage. Covering of microfractured defects with the cell-free polymer-based cartilage implant is suggested to be a promising treatment option for cartilage defects and improves the regeneration of articular cartilage. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1353,1360, 2009 [source]

Transgene-activated mesenchymal cells for articular cartilage repair: a comparison of primary bone marrow-, perichondrium/periosteum- and fat-derived cells

Jung Park
Abstract Background Adult primary mesenchymal cells of different origin which can be obtained with minor donor site morbidity are considered for articular cartilage repair. This study aims at a comparison of their chondrogenic potential. Methods Mesenchymal cells were isolated from perichondrium/periosteum, bone marrow or fat of adult rats and found to be positive for the stem-cell-related antigens Sca-1, c-Kit, CD10, CD13 and CD90 by reverse transcription polymerase chain reaction (RT-PCR). Chondrogenic differentiation was induced by applying recombinant bone morphogenetic protein-2 (BMP-2) or adenoviral vectors carrying BMP-2 cDNA, followed by micromass culture. The stimulated cells were characterized by RT-PCR, cell proliferation and apoptosis assays. Expression of aggrecan, collagen type I, II, IX and X and alkaline phosphatase genes was analyzed by RT-PCR, immunofluorescence and immunohistochemistry in comparison with unstimulated control cells. Adenovirally stimulated cells were transplanted into mechanically generated partial-thickness cartilage lesions in the patellar groove of the rat femur. Quality and integration of the repair tissues were assessed by histochemical and immunohistochemical methods. Results Stimulation with BMP-2 or AdBMP-2 led to an up-regulation of cartilage-specific gene expression in all three cell populations studied, most rapidly and prominently in the perichondrial/periosteal cells, which showed a 3200-fold increase of type II collagen mRNA and reached the highest absolute levels of type II and IX collagen transcripts after stimulation. Similar results were obtained for the bone marrow stromal cells (BMSC), while the respective transcript levels in fat stromal cells declined after an initial more than 30-fold elevation. Following transplantation in vivo, AdBMP-2-infected perichondrial/periosteal cells produced a proteoglycan-rich, type II collagen-positive matrix with only faint staining for type I collagen. The repair tissue originating from AdBMP-2-infected BMSC showed less intense type II collagen staining, but a relatively proteoglycan-rich matrix, weakly positive for type I collagen. Transgene-activated fat stromal cells formed rather fibrous tissue mainly composed of type I collagen. Unstimulated cells of the three different populations gave only rise to fibrous tissue. Conclusions Perichondrium/periosteum-derived cells and BMSC seem superior to cells isolated from fat with respect to forming hyaline cartilaginous tissue. A chondrogenic stimulus, e.g. by transfer of BMP-2 cDNA, appears to be required for initiation and support of chondrogenic differentiation. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Shear stress magnitude and duration modulates matrix composition and tensile mechanical properties in engineered cartilaginous tissue

Christopher V. Gemmiti
Abstract Cartilage tissue-engineering strategies aim to produce a functional extracellular matrix similar to that of the native tissue. However, none of the myriad approaches taken have successfully generated a construct possessing the structure, composition, and mechanical properties of healthy articular cartilage. One possible approach to modulating the matrix composition and mechanical properties of engineered tissues is through the use of bioreactor-driven mechanical stimulation. In this study, we hypothesized that exposing scaffold-free cartilaginous tissue constructs to 7 days of continuous shear stress at 0.001 or 0.1,Pa would increase collagen deposition and tensile mechanical properties compared to that of static controls. Histologically, type II collagen staining was evident in all construct groups, while a surface layer of type I collagen increased in thickness with increasing shear stress magnitude. The areal fraction of type I collagen was higher in the 0.1-Pa group (25.2,±,2.2%) than either the 0.001-Pa (13.6,±,3.8%) or the static (7.9,±,1.5%) group. Type II collagen content, as assessed by ELISA, was also higher in the 0.1-Pa group (7.5,±,2.1%) compared to the 0.001-Pa (3.0,±,2.25%) or static groups (3.7,±,3.2%). Temporal gene expression analysis showed a flow-induced increase in type I and type II collagen expression within 24,h of exposure. Interestingly, while the 0.1-Pa group showed higher collagen content, this group retained less sulfated glycosaminoglycans in the matrix over time in bioreactor culture. Increases in both tensile Young's modulus and ultimate strength were observed with increasing shear stress, yielding constructs possessing a modulus of nearly 5,MPa and strength of 1.3,MPa. This study demonstrates that shear stress is a potent modulator of both the amount and type of synthesized extracellular matrix constituents in engineered cartilaginous tissue with corresponding effects on mechanical function. Biotechnol. Bioeng. 2009; 104: 809,820 © 2009 Wiley Periodicals, Inc. [source]

Application of polyethyleneimine-modified scaffolds to the regeneration of cartilaginous tissue

Yung-Chih Kuo
Abstract In this study, we analyzed the physicochemical and biophysical properties of three-dimensional scaffolds modified using polyethyleneimine (PEI) and applied these scaffolds to the cultivation of bovine knee chondrocytes (BKCs). PEI was crosslinked in the bulk or on the surface of the ternary scaffolds comprising polyethylene oxide, chitin and chitosan. The results revealed that when the concentration of PEI was less than 300 ,g/mL, the cytotoxicity of a scaffold was on the same order in the two method of modification. An increase in the concentration of PEI favored the adhesion of BKCs. When the amount of PEI in scaffolds is fixed, the surface-modified scaffolds exhibited a higher adhesion efficiency of BKCs than the bulk-modified scaffolds. For the regeneration of cartilaginous components, a higher amount of PEI in a scaffold yielded larger amounts of proliferated BKCs, secreted glycosaminoglycans, and produced collagen. In addition, the formation of neocartilage in the surface-modified scaffolds was more effective than that in the bulk-modified scaffolds. These tissue-engineered scaffolds, modified by an appropriate concentration of PEI, can be potentially applied to cartilage repair in clinical trials. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source]

Expression of extracellular matrix molecules typical of articular cartilage in the human scapholunate interosseous ligament

S. Milz
Abstract The scapholunate interosseous ligament (SLIL) connects the scaphoid and lunate bones and plays a crucial role in carpal kinematics. Its rupture leads to carpal instability and impairment of radiocarpal joint function. As the ligament is one of the first structures affected in rheumatoid arthritis, we conducted an immunohistochemical study of cadaveric tissue to determine whether it contains known autoantigens for rheumatoid arthritis. We immunolabelled the ligament from one hand in 12 cadavers with monoclonal antibodies directed against a wide range of extracellular matrix (ECM) molecules associated with both fibrous and cartilaginous tissues. The labelling profile has also enabled us to comment on how the molecular composition of the ligament relates to its mechanical function. All regions of the ligament labelled for types I, III and VI collagens, chondroitin 4 and 6 sulphates, keratan sulphate, dermatan sulphate, versican, tenascin and cartilage oligomeric matrix protein (COMP). However, both entheses labelled strongly for type II collagen, aggrecan and link protein and were distinctly fibrocartilaginous. In some regions, the ligament attached to bone via a region of hyaline cartilage that was continuous with articular cartilage. Labelling for cartilage molecules in the midsubstance was most evident dorsally. We conclude that the SLIL has an ECM which is typical of other highly fibrocartilaginous ligaments that experience both tensile load and shear. The presence of aggrecan, link protein, COMP and type II collagen could explain why the ligament may be a target for autoantigenic destruction in some forms of rheumatoid arthritis. [source]

Transcriptional profiling and biochemical analysis of mechanically induced cartilaginous tissues in a rat model

Kristy T. Salisbury Palomares
Objective To characterize patterns of molecular expression that lead to cartilage formation in vivo in a postnatal setting, by profiling messenger RNA expression across the time course of mechanically induced chondrogenesis. Methods Retired breeder Sprague-Dawley rats underwent a noncritical-sized transverse femoral osteotomy. Experimental animals (n = 45) were subjected to bending stimulation (60° cyclic motion in the sagittal plane for 15 minutes/day) of the osteotomy gap beginning on day 10 after the operation. Control animals (n = 32) experienced continuous rigid fixation. Messenger RNA isolated on days 10, 17, 24, and 38 after surgery was analyzed using a microarray containing 608 genes involved in skeletal development, tissue differentiation, fracture healing, and mechanotransduction. The glycosaminoglycan (GAG) content in the stimulated tissues was compared with that in native articular cartilage as a means of assessing the progression of chondrogenic development of the tissues. Results The majority of the 100 genes that were differentially expressed were up-regulated in response to mechanical stimulation. Many of these genes are associated with articular cartilage development and maintenance, diarthrodial joint development, cell adhesion, extracellular matrix synthesis, signal transduction, and skeletal development. Quantitative real-time polymerase chain reaction results were consistent with the microarray findings. The GAG content of the stimulated tissues increased over time and was no different from that of articular cartilage on day 38 after surgery. Conclusion Our findings indicate that mechanical stimulation causes up-regulation of genes that are principally involved in joint cavity morphogenesis and critical to articular cartilage function. Further study of this type of stimulation may identify key signaling events required for postnatal hyaline cartilage formation. [source]