Showing papers on "Cartilage published in 1979"
TL;DR: The aggregation defect was rapidly reversible and aggregates were again normal size 2 weeks after removal of a cast that had been worn for 6 weeks.
Abstract: Healthy adult dogs were studied for a defect in proteoglycan aggregation by immobilizing one limb for varying periods of time. Immobilization for 6 days resulted in a 41% reduction in proteoglycan synthesis by articular cartilage from the restrained knee compared with the contralateral control knee. After 3 weeks of immobilization, proteoglycan aggregation was no longer demonstrable in cartilage from the constrained limb. The aggregation defect was rapidly reversible and aggregates were again normal size 2 weeks after removal of a cast that had been worn for 6 weeks.
298 citations
TL;DR: Evidence is presented that the catabolic factor is a protein, and a quantitative assay for the factor, for which the cartilage of bovine nasal septum is used, is described.
Abstract: Porcine synovium in organ culture produces a factor that causes chondrocytes to degrade their matrix. A quantitative assay for the factor, for which the cartilage of bovine nasal septum is used, is described. Evidence is presented that the catabolic factor is a protein.
237 citations
TL;DR: Eighty-five patients who had patellar spongialization and were followed from 6--36 months (average 15 months) are reported, with 79% reporting good or excellent results.
Abstract: Spongialization is an extension of the concept of Pridie for resurfacing damaged joints. The diseased cartilage is excised and the subchondral plate completely removed exposing the cancellous bone or "spongiosa" from which a new fibrous tissue surface can grow. The technique is particularly applicable to a localized lesion of the patella. Eighty-five patients who had patellar spongialization and were followed from 6--36 months (average 15 months) are reported, with 79% reporting good or excellent results. Provided that there was severe cartilage damage in each case, the early results are better than with either patellectomy or "shaving" of the diseased cartilage.
190 citations
TL;DR: These measurements showed that the deformations of femiral-head articular cartilage under load in the intact joint are non-uniform and increase greatly with age, which implies changes in the fundamental mechanical properties of the cartilage with age.
Abstract: Using a new roentgenographic technique for measuring cartilage deformation in intact joint specimens, twenty-eight normal human hip joints from subjects twenty-five to eighty-five years old were loaded with a force of five times body weight in a testing machine. The initial unloaded thickness of the articular cartilage of the femoral head and the changes in thickness of this cartilage under load were measured roentgenographically at seven to twelve sites on each femoral head. These measurements showed that the deformations of femiral-head articular cartilage under load in the intact joint are non-uniform and increase greatly with age. In twelve specimens measurements were also made of the increase in cartilage deformation with time when the load of five times body weight was maintained on the joint. A single osteoarthrotic joint was also studied. The experimental findings imply changes in the fundamental mechanical properties of the cartilage with age, which probably result from age-related alterations in cartilage microstructure and chemical composition.
157 citations
TL;DR: The observations reported here suggest that initial cell plating densities may provide environmental conditions deterministic to a particular limb phenotype, and relating differential vascularization and nutrient flow to the determination of limb phenotypes in vivo is presented.
137 citations
TL;DR: This chapter discusses large scale preparation of chondrocytes, which is one type of cell of the cartilage, which are useful for the analysis of proteoglycan synthesis and collagen synthesis.
Abstract: Publisher Summary This chapter discusses large scale preparation of chondrocytes, which is one type of cell of the cartilage. Chondrocytes are useful for the analysis of proteoglycan synthesis and collagen synthesis. The metabolic effects of polypeptide growth factors, hormones, and vitamins on chondrocytes are also studied. Chondrocytes are obtainable in large numbers from bovine and human sources. A source of large numbers of human chondrocytes is the costal cartilage obtained from children undergoing surgical correction of pectus excavatum, a disorder in which rib cartilage is deformed. These chondrocytes are particularly easy to isolate because the perichondrium, muscle, and connective tissue are removed from the cartilage during surgery. Chondrocytes cannot be maintained indefinitely in culture flasks once they become confluent because the synthesis of the sulfated proteoglycans leads to a sharp decrease in the pH of the media. A major problem in chondrocyte culture is the possibility of contamination by fibroblasts arising from the perichondrium. Cartilage in vivo contains Type II collagen that is genetically distinct from the Type I collagen found in skin, bone, and tendon.
127 citations
TL;DR: Using lesion incidence and a scoring system which provided an overall estimation of both gross and microscopic findings, the arthropathic index was higher in dogs receiving pipemidic acid, thus demonstrating the greater arthropATHogenic potential of this chemical.
127 citations
TL;DR: In the late stages of the arthritis there was a progressive decrease in the rate of glycosaminoglycan synthesis and a relative decrease in chrondroitin sulphate synthesis compared with keratan sulphates synthesis, and these decreases were highly correlated with the histological grade.
Abstract: Biochemical changes and in vitro rates of glycosaminoglycan synthesis were studied in thirty-seven samples of human articular cartilage from nineteen osteoarthritic and four normal control patients who were fifty to seventy-five years old. The samples were compared on the basis of histological grade of the arthritis, and subgroups based on the duration of disease, synovial pathological changes, joint studied, and sex were also compared. The osteoarthritic samples showed a progressive loss of glycosaminoglycans in the cartilage as the histological grade increased. In the early stages of the disease there was an increase in the chondroitin sulphate content as well as in the rate of glycosaminoglycan synthesis in several cases when the values for the osteoarthritic articular-cartilage samples were compared with those for the age-matched controls. In the late stages there was a progressive decrease in the rate of glycosaminoglycan synthesis and a relative decrease in chrondroitin sulphate synthesis compared with keratan sulphate synthesis, and these decreases were highly correlated with the histological grade.
111 citations
TL;DR: Proteoglycans were extracted from bovine tracheal cartilage by high-speed homogenization, the use of dissociative solvents being avoided, indicating an interaction with cartilage matrix protein-proteoglycan complex.
Abstract: Proteoglycans were extracted from bovine tracheal cartilage by high-speed homogenization, the use of dissociative solvents being avoided. The homogenate was fractionated by gel chromatography, sucrose-density-gradient centrifugation and ion-exchange chromatography. A previously unrecognized protein, cartilage matrix protein, was identified by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. It cofractionated with the proteoglycans in all systems, indicating an interaction. The cartilage matrix protein-proteoglycan complex was dissociated by treatment with 4M-guanidinium chloride. The complex again formed when the guanidine was removed. The cartilage matrix protein has a mol.wt. of more than 200000. On reduction it yields subunits with a mol.wt. of approx. 60000.
107 citations
TL;DR: The demonstrated ability of 0.5 M GuHCl to extract large amounts of PG from osteoarthritic cartilage will allow study of cartilage proteoglycans in their native nondissociated state and is consistent with a disorder of link protein, hyaluronic acid, or PG subunit hyaluonic acid binding sites.
Abstract: Size distribution of cartilage proteoglycans (PG) extracted from control and osteoarthritic rabbit knees after partial meniscectomy was analyzed. In normal control knees, about 30% of PG molecules were in aggregate form and average sedimentation constant was 60S. No aggregates were found in osteoarthritic cartilage, whether ulcer, rim about ulcer, or distant normal-appearing cartilage was examined. Weight average sedimentation constants for PG subunits were similar to controls, 15S. Up to 70% of guanidinium-extractable PG could be extracted from osteoarthritic cartilage by using 0.5M guanidine HC1 (GuHCl); sedimentation characteristics of extracted PG were similar to those using 4.0M GuHCl. Absence of aggregates is consistent with a disorder of link protein, hyaluronic acid, or PG subunit hyaluronic acid binding sites. Absence of subunit degradation was an enexpected finding. The demonstrated ability of 0.5 M GuHCl to extract large amounts of PG from osteoarthritic cartilage will allow study of cartilage proteoglycans in their native nondissociated state.
106 citations
TL;DR: The view that a significant component of cartilage breakdown may be chondrocyte-mediated is supported, as well as the interaction of living synovium with live cartilage.
Abstract: 1. The destruction of articular cartilage in human rheumatoid and other arthritides is the result of diverse mechanical, inflammatory and local cellular factors. A tissue-culture model for studying cartilage–synovial interactions that may be involved in the final common pathway of joint destruction is described. 2. Matrix breakdown was studied in vitro by using bovine nasal-cartilage discs cultivated in contact with synovium. Synovia were obtained from human and animal sources. Human tissue came from patients with ‘classical’ rheumatoid arthritis, and animal tissue from rabbits with antigen-induced arthritis. 3. Cartilage discs increased their proteoglycan content 2–3-fold during 8 days in culture. Proteoglycan was also released into culture medium, approx. 70% arising from cartilage breakdown. 4. Synovial explants from human rheumatoid and rabbit antigen-induced arthritis produced equivalent stimulation of proteoglycan release. After an initial lag phase, the breakdown rate rose abruptly to a maximum, resulting in a 2-fold increase of proteoglycan accumulation in culture medium after 8–10 days. 5. High-molecular-weight products shed into culture media were characterized chromatographically and by differential enzymic digestion. Proteoglycan–chondroitin sulphate accounted for 90% of the released polyanion, and its partial degradation in the presence of synovial explants was consistent with limited proteolytic cleavage. 6. Rheumatoid synovium applied to dead cartilage increased the basal rate of proteoglycan release. Living cartilage was capable of more extensive autolysis, even in the absence of synovium. However, optimal proteoglycan release required the interaction of living synovium with live cartilage. These findings support the view that a significant component of cartilage breakdown may be chondrocyte-mediated.
TL;DR: It is concluded that the structural integrity of the proteoglycan macromolecule is essential for its effect on cell adhesion.
Abstract: Proteoglycan was isolated from cartilage and freed from contaminating glycoproteins and hyaluronic acid. The macromolecule consists of a protein core covalently linked to a number of glycosaminoglycan side chains, namely chondroitin sulphate and keratan sulphate. This proteoglycan retards the attachment of a variety of cell types to tissue culture plastic and to collagen. Glycosaminoglycans alone, have no significant effect on rates of attachment. Similarly, trypsinized proteoglycan is without effect. It is concluded that the structural integrity of the proteoglycan macromolecule is essential for its effect on cell adhesion.
TL;DR: The tesserate pattern of endoskeletal calcification has been investigated in jaws, gill arches, vertebral arches and fins of the sharks Carcharhinus menisorrah, Triaenodon obesus and Negaprion brevirostris by techniques of light and electron microscopy.
Abstract: The tesserate pattern of endoskeletal calcification has been investigated in jaws, gill arches, vertebral arches and fins of the sharks Carcharhinus menisorrah, Triaenodon obesus and Negaprion brevirostris by techniques of light and electron microscopy. Individual tesserae develop peripherally at the boundary between cartilage and perichondrium. An inner zone, the body, is composed of calcified cartilage containing viable chondrocytes separated by basophilic contour lines which have been called Liesegang waves or rings. The outer zone of tesserae, the cap, is composed of calcified tissue which appears to be produced by perichondrial fibroblasts more directly, i.e., without first differentiating as chondroblasts. Furthermore, the cap zone is penetrated by acidophilic Sharpey fibers of collagen. It is suggested that scleroblasts of the cap zone could be classified as osteoblasts. If so, the cap could be considered a thin veneer of bone atop the calcified cartilage of the body of a tessera. By scanning electron microscopy it was observed that outer and inner surfaces of tesserae differ in appearance. Calcospherites and hydroxyapatite crystals similar to those commonly seen on the surface of bone are present on the outer surface of the tessera adjacent to the perichondrium. On the inner surface adjoining hyaline cartilage, however, calcospherites of variable size are the predominant surface feature. Transmission electron microscopy shows calcification in close association with coarse collagen fibrils on the outer side of a tessera, but such fibrils are absent from the cartilaginous matrix along the under side of tesserae. Calcified cartilage as a tissue type in the endoskeleton of sharks is a primitive vertebrate characteristic. Calcification in the tesserate pattern occurring in modern Chondrichthyes may be derived from an ancestral pattern of a continuous bed of calcified cartilage underlying a layer of perichondral bone, as theorized by Orvig (1951); or the tesserate pattern in these fish may itself be primitive.
TL;DR: Naproxen, a prostaglandin synthetase inhibitor which is an effective antiinflammatory agent in laboratory animals and humans, was evaluated as an inhibitor of connective tissue destruction in this model by use of radiologic and histopathologic analyses.
Abstract: The Freund's adjuvant-injected rat shares a number of features with the arthritis patient, viz the presence of a proliferative synovitis, joint swelling, and cartilage and bone erosion. Naproxen, a prostaglandin synthetase inhibitor which is an effective antiinflammatory agent in laboratory animals and humans, was evaluated as an inhibitor of connective tissue destruction in this model by use of radiologic and histopathologic analyses. Sixteen days after rats were injected with Freund's complete adjuvant, marked joint swelling was noted. On day 17, vehicle or naproxen, 7 mg/kg/day, was administered orally. Twenty-eight days later vehicle-treated animals demonstrated the following pathologic changes in their hindpaws; swelling, cartilage loss, large amounts of pannus within the joint spaces, osteoporosis, bone erosions, periosteal new bone formation, heterotopic ossification, and bony ankylosis. Rats treated 28 days with naproxen had significantly milder disease than the vehicle controls. The incidence of severe juxtaarticular bone destruction was 10/10 in the vehicle controls versus 2/10 of the drug-treated group (P less than 0.01). A comparable reduction in cartilage erosion, incidence of pannus, and new bone formation was noted in the drug-treated group. These effects may relate to an inhibition of prostaglandin biosynthesis; prostaglandins have been shown to: 1) stimulate collagenase secretion from macrophages, 2) stimulate bone resorption in vivo and in vitro, and 3) diminish proteoglycan synthesis in cartilage.
TL;DR: Osteophyte proteoglycan metabolism differed from other osteoarthritic lesions, and differences in the metabolism of femoral and tibial articular cartilage were observed.
Abstract: Estradiol valerate did not ameliorate experimentally induced osteoarthritis in the rabbit. Both normal and osteoarthritic cartilage were susceptible to estradiol suppression of proteoglycan synthesis. Protoeglycan concentration was not diminished with estradiol, suggesting estradiol suppression of proteoglycan catabolism. The severity of osteoarthritis was unchanged despite markedly decreased proteoglycan catabolism. The severity of osteoarthritis was unchanged despite markedly decreased protoeglycan synthesis in the estrogen treated animals. Osteophyte proteoglycan metabolism differed from other osteoarthritic lesions. Differences in the metabolism of femoral and tibial articular cartilage were observed.
TL;DR: The hydrodynamic size of newly synthesized proteoglycan aggregates and of disaggregated proteoglycans was unaffected by sodium salicylate, while higher concentrations of the drug increased the rate of degradation.
Abstract: In osteoarthritis, diminished aggregation of articular cartilage proteoglycans affects tissue biomechanics. Since salicylates are commonly employed in treatment of osteoarthritis, we examined the effect of sodium salicylate on proteoglycan metabolism and aggregation in normal canine articular cartilage. At salicylate concentrations of 10(-3)M, 5 X 10(-3)M and 10(-2)M, net proteoglycan synthesis in normal canine articular cartilage was 73%, 42% and 16% respectively, of control levels. Catabolism of glycosaminoglycans in the presence of 10(-3)M salicylate (which corresponds to a serum salicylate level of 20-25 mg %) was the same as that in control cartilage, while higher concentrations of the drug increased the rate of degradation. The hydrodynamic size of newly synthesized proteoglycan aggregates and of disaggregated proteoglycans was unaffected by sodium salicylate.
TL;DR: Application of tissue culture techniques to the storage of articular cartilage made it possible to preserve cartilage slice explants in a viable, biochemically "normal" state.
Abstract: Articular cartilage slice explants were stored under various conditions, including freezing-thawing at various rates by using dimethyl sulfoxide (DMSO) as a cryoprotective agent, incubating in standard tissue culture medium (MEM Eagle:NCTC 135:15% fetal calf serum) in 5% CO2 and air at 4 degrees, 21 degrees, and 37 degrees C, and incubating in standard tissue culture medium containing 200 micrograms/ml alpha-tocopherol (vitamin E) at 37 degrees C after first ascertaining a dose-response curve of vitamin E. Results indicated that articular cartilage slice explants did not survive freezing or storage at 4 degrees and 21 degrees C as measured by 35S uptake. When stored at 37 degrees C in standard tissue culture in 5% CO2 and air, the slice explants remained viable for up to 60 days. The addition of alpha-tocopherol to the medium resulted in significantly less release of previously incorporated 35Sin stored cartilage slices and significantly less reduction of the amount of hexosamine present in the stored explants. alpha-Tocopherol in the medium also preserved safranin O staining. Thus, the application of tissue culture techniques to the storage of articular cartilage made it possible to preserve cartilage slice explants in a viable, biochemically "normal" state.
TL;DR: Conclusively cartilage formation from grafted rib perichondrium is achieved in the knee joints of adult dogs, but it does not resist considerable pressure forces.
Abstract: The cartilaginous potential of the perichondri-um has earlier been utilized to reconstruct articular cartilage in unloaded joints in adult rabbits. The present work in adult dogs has been performed to find out if the perichondrium can be used for the same purpose in joints subjected to pressure. In 13 knee joints the articular cartilage of the patella was excised completely and the resected surface was covered with an autologous perichon-drial graft taken from the rib cartilage. After 3 weeks of immobilization the dogs were allowed to run freely until sacrifice 2 to 17 months later. In all 13 cases regeneration of cartilage took place. Within 8 months the regenerated cartilage showed no or only very slight degenerative signs but from 12 months and later such changes were common. In control cases where the resected surface was left without any graft no cartilage at all was found. Conclusively cartilage formation from grafted rib perichondrium is achieved in the knee joints of adult dogs, but it does not re...
TL;DR: Wear of high-density polyethylene on bone and cartilage has resulted in a large volume of plastic particles being shed into the two knees and two hips studied, making revision impossible.
Abstract: Wear of high-density polyethylene on bone and cartilage has resulted in a large volume of plastic particles being shed into the two knees and two hips studied. The giant-cell foreign-body reaction of the synovium may not be sufficient to cope with the amount of debris presented and the destruction of the endosteal bone in one hip, caused by the wear particles and movement of the prosthesis, has made revision impossible. Articulation of high-density polyethylene against bone or cartilage either by design or by the failure of alignment of the component must be avoided.
TL;DR: Rabbit perichondrium from the rib appeared to have a greater cartilaginous potential than that from the ear both in vivo and in vitro.
Abstract: In an experimental study the cartilaginous potential of the rabbit ear perichondrium has been compared with that of the rib in vivo and in vitro. Perichondrium was transferred as free autologous grafts to the subcutaneous tissue on the scalp and as loose bodies into the knee joint. The presence of cartilage in the grafts was examined after six weeks. In vitro explants of rabbit perichondrium from the ear and the rib were maintained in an organ culture system. The presence of cartilage was analyzed after one to three weeks. Rabbit perichondrium from the rib appeared to have a greater cartilaginous potential than that from the ear both in vivo and in vitro. Chondrogenesis in perichondrium was demonstrated in vitro.
TL;DR: It appears that the link-protein is not structurally related to the proteoglycan or the hyaluronic acid-binding region, and it is feasible to quantitatively determine its substructures by using the antisera described above.
Abstract: Antibodies were raised in rabbits by injection of cartilage proteoglycan monomers, isolated hyaluronic acid-binding region, polysaccharide-peptides prepared by trypsin digestion of proteoglycans and link-protein. The rabbits injected with the proteoglycan monomers made antibodies reacting with the intact proteoglycan. The antiserum contained antibodies specific for, and also reacting with, the isolated hyaluronic acid-binding region and the keratan sulphate-rich region. In addition there were probably antibodies reacting with other structures of the proteoglycan monomer. When isolated hyaluronic acid-binding region was used for immunization the antibodies obtained reacted specifically with the hyaluronic acid-binding region. The antibodies obtained from rabbits immunized with the polysaccharide-peptides reacted with the proteoglycan monomers and showed a reaction identical with that of the chondroitin sulphate-peptides isolated after trypsin digestion of proteoglycans. The antibodies prepared with the link-protein as the antigen reacted only with the link-protein and not with any preparation from the proteoglycan monomer. Neither did any of the antisera raised against the proteoglycan monomer or its substructures react with the link-protein. Separately it was shown that the peptide 'maps' prepared from trypsin digests of the link-protein and the hyaluronic acid-binding region were different. Therefore it appears that the link-protein is not structurally related to the proteoglycan or the hyaluronic acid-binding region. Digestion of proteoglycan monomers or isolated hyaluronic acid-binding region with trypsin did not destroy the antigenic sites of the hyaluronic acid-binding region. In contrast trypsin digests of previously reduced and alkylated preparations did not react with the anti-(hyaluronic acid-binding region). The trypsin digests, however, reacted with both the antibodies directed against the chondroitin sulphate-peptides and those against the keratan sulphate-peptides. Trypsin digestion of the link-proteins destroyed the antigenic site and the reactivity with the antibodies. By combining immunoassay of proteoglycan preparations before and after trypsin digestion it is feasible to quantitatively determine its substructures by using the antisera described above.
TL;DR: A quantitative comparison of cartilage differentiation was made between micromass cell cultures prepared with cells from different locations within prechondrogenic chick wing buds, finding that a stage 23–24 wing bud contains two classes of cells, each characterized by a bias for either cartilage or muscle differentiation, and a third class of uncharacterized mesenchymal cells.
TL;DR: An experimental study in adult rabbits to find out whether the cartilage forming capacity of the perichondrium could be utilized in reconstruction of articular cartilage found regeneration of cartilage occurred in 12 out of 14 grafted rabbits.
Abstract: An experimental study in adult rabbits has been performed to find out whether the cartilage forming capacity of the perichondrium could be utilized in reconstruction of articular cartilage. The normal articular cartilage of the glenoid surface of the humero-scapular joint was completely removed. Auricular perichondrium was grafted to cover the exposed bony surface with the active chondrogenic layer of the perichondrial graft facing the joint cavity. The joint was not immobilized but the operated limb was amputated at wrist level to avoid weight bearing. The animals were sacrificed at different time intervals ranging from 1 to 17 weeks. In 12 out of 14 grafted rabbits regeneration of cartilage occurred. In 6 of 10 control cases where no perichondrium was grafted to cover the resected surface no cartilage was found. In the other 4, only small areas of mature cartilage were seen, probably remnants of the original articular cartilage.
TL;DR: The results reveal the local influence of insoluble collagenous bone matrix on proliferation of mesenchymal cells and imply a role for this extracellular matrix in anchorage-dependent events in cell growth and differentiation.
Abstract: THE importance of collagens in growth and differentiation1,2 and in cell adhesion3 is well documented. We have previously shown that cell-free, demineralised, collagenous bone matrix induces the formation of cartilage, bone and bone marrow4–6. One of the early responses to implanted collagenous matrix is the appearance of connective tissue mesenchymal cells adjacent to the implanted matrix before their differentiation into cartilage. We present here direct evidence that collagenous bone matrix is a local mitogen for connective tissue cells. We find that the collagenous bone matrix is a potent inducer of ornithine decarboxylase (EC 4.1.1.17, ODC), an enzyme involved in polyamine biosynthesis7 and considered as an early marker of cell proliferation8. These studies have been corroborated by incorporation of 3H-thymidine into acid-precipitable material and by autoradiography. Our results reveal the local influence of insoluble collagenous bone matrix on proliferation of mesenchymal cells and imply a role for this extracellular matrix in anchorage-dependent9 events in cell growth and differentiation.
TL;DR: Perichondrial grafts are the newest frontier in cartilage transplantation, supplying the capacity for neochondrogenesis while providing architectural support in reconstruction of the nose, the auditory canal, or the temporomandibular joint.
TL;DR: Human articular cartilage was obtained post mortem from the lateral femoral condyles of 30 subjects aged from under 1 to 70 years and changes with age were observed in GAG concentration and in the proportion of individual GAG.
Abstract: Human articular cartilage was obtained post mortem from the lateral femoral condyles of 30 subjects aged from under 1 to 70 years. Cryostat sections taken 0--100 micrometers and 900--100 micrometers deep to the cartilage surface were exhaustively extracted to recover the glycosaminoglycans (GAG). After fractionation by cellulose acetate electrophoresis and enzyme depolymerisation individual GAG were determined by alcian blue -0.05 M MgCl2 and disaccharide microassay procedures. Changes with age were observed in GAG concentration and in the proportion of individual GAG. Large alterations occurred during the period of skeletal growth (0--16y). At birth GAG formed about 50% of the dry weight of cartilage, a value that decreased to about 15% in adult cartilage. Chondroitin sulphates (ChS) formed the principal GAG of articular cartilage and accounted for almost all of the GAG of the infant material. The ChS decreased with age and were partially replaced by keratan sulphate (KS), so the KS eventually comprised 12% of the GAG. Hyaluronic acid (HA) was identified and was found to increase linearly with age to form 6% by weight of the cartilage GAG by 60y.
TL;DR: It is suggested that fibroblasts may act as effector cells in producing collagenase and degrading collagen in response to soluble factors released by macrophages under the control of lymphocyte factors.
Abstract: Rabbit bone-marrow macrophages and fibroblasts were cultured, independently or together, with pieces of 35S-labelled cartilage or at the surface of dried [14C]collagen gels. Each type of cell, cultivated alone, rapidly degraded the proteoglycan of cartilage, but only the fibroblasts degraded collagen. The co-culture of both types of cell had no consistent effect on the rate of proteoglycan degradation, but it stimulated the rate of collagen degradation. In parallel, the accumulation of collagenase in the culture fluid was enhanced but not that of neutral proteinase. Coinditioned media from macrophage cultures added to cultures of fibroblasts had the same effect as the living macrophages in stimulating the production of collagenase. Their action was itself enhanced when the macrophages had been activated by concanavalin A-stimulated spleen-cell factors. These data suggest that fibroblasts may act as effector cells in producing collagenase and degrading collagen in response to soluble factors released by macrophages under the control of lymphocyte factors.
Journal Article•
TL;DR: The present studies indicate that in the growth of cartilage canals the cartilage is removed by chondroclasts which stem from the primitive connective tissue cells of the perichondrium which provide the osteoblasts which establish the secondary centre of ossification.
Abstract: The present studies indicate that in the growth of cartilage canals the cartilage is removed by chondroclasts which stem from the primitive connective tissue cells of the perichondrium. Besides fusing to form multinucleated chondroclasts, these cells also provide the osteoblasts which establish the secondary centre of ossification. The growing tips of the blood vessels within the canals are also fashioned from these primitive connective tissue cells as they invade the microhaemorrhages at the ends of the canals. This is an identical procedure to that found in the vascular invasion of the primary growth plate. The cartilage canals are clearly useful sites in which to study the development of osteoclasts and chondroclasts from more primitive (osteoprogenitor) cells.
TL;DR: The results support the belief that in a clinical setting it is important to preserve perichondrium because it facilitates growth of new cartilage and bone and suggests that when autogenous tissue is to be used for subcutaneous augmentation, it is best to use crushed or uncrushed cartilage or uncRushed bone because they remain viable.
Abstract: • This study evaluated autografts of bone and cartilage, uncrushed and crushed, in the perichondrial space of the ear and subcutaneously in the paraspinal region in rabbits six weeks and six months after transplantation. The results support the belief that in a clinical setting it is important to preserve perichondrium because it facilitates growth of new cartilage. This study suggests that when autogenous tissue is to be used for subcutaneous augmentation, it is best to use crushed or uncrushed cartilage or uncrushed bone because they remain viable. In the perichondrial space, crushed and uncrushed cartilage grafts not only remain viable but also induce growth of new cartilage and bone. Autogenouscrushedbone does not survive in the perichondrial space of the rabbit ear. (Arch Otolaryngol105:75-80, 1979)
TL;DR: The view that a significant component of cartilage breakdown may be chondrocyte-mediated is supported, as well as the interaction of living synovium with live cartilage.
Abstract: The effects of hydrocortisone, indomethacin, and gold thiomalate on proteoglycan release were assessed in bovine nasal cartilage-rheumatoid synovium cocultures. Of the three agents, only hydrocortisone consistently inhibited both basal and synovium-stimulated cartilage breakdown. Hydrocortisone responsivity was a direct function of the degradative capacity of synovial specimens, and this was equally well demonstrated both in patients receiving long-term therapy and those given perioperative glucocorticoid therapy. The data are consistent with significant hydrocortisone inhibition of lysosomal enzyme-mediated degradation of cartilage.