Showing papers on "Cartilage published in 1983"

Structure of proteoglycans from different layers of human articular cartilage.

Abstract: Full-depth plugs of adult human articular cartilage were cut into serial slices from the articular surface and analysed for their glycosaminoglycan content. The amount of chondroitin sulphate was highest in the mid-zone, whereas keratan sulphate increased progressively through the depth. Proteoglycans were isolated from each layer by extraction with 4M-guanidinium chloride followed by centrifugation in 0.4M-guanidinium chloride/CsCl at a starting density of 1.5 g/ml. The efficiency with which proteoglycans were extracted depended on slice thickness, and extraction was complete only when cartilage from each zone was sectioned at 20 microns or less. When thick sections (250 microns) were extracted, hyaluronic acid was retained in the tissue. Most of the proteoglycans, extracted from each layer under optimum conditions, could interact with hyaluronic acid to form aggregates, although the extent of aggregation was less in the deeper layers. Two pools of proteoglycan were identified in all layers by gel chromatography (Kav. 0.33 and 0.58). The smaller of these was rich in keratan sulphate and protein, and gradually increased in proportion through the cartilage depth. Chondroitin sulphate chain size was constant in all regions. The changes in composition and structure observed were consistent with the current model for hyaline-cartilage proteoglycans and were similar to those observed with increasing age in human articular cartilage.

The effects of indirect blunt trauma on adult canine articular cartilage.

Abstract: In order to determine the effect of subfracture loads on articular cartilage, we impacted twelve adult canine patellofemoral joints utilizing a drop-tower with two different force-levels The joints were examined with light and electron microscopy at two, four, and six weeks after impaction In ten additional animals a single knee was impacted and they were analyzed biochemically at similar time-periods, using the contralateral joint as a control In all impacted specimens changes were observed in the zone of calcified cartilage, represented by an increase in cellular clones, vascular invasion, and proteoglycan content of the matrix Ultrastructural evaluation of the superficial and deep radial zones of the articular cartilage revealed loss of the cellular processes and territorial matrices of chondrocytes in both layers Ruthenium-red staining of impacted samples revealed a 40 per cent decrease in proteoglycan associated with collagen fibers in the extraterritorial matrix An increase in collagen-fiber width was observed in the four and six-week groups The earliest changes in articular cartilage included activation of the zone of calcified cartilage as well as ultrastructural alterations in the superficial and radial zones Biochemical analysis revealed an increase in water content and hexuronic acid at two weeks These changes occurred at a subfracture level in the absence of surface disruption CLINICAL RELEVANCE: These animal experiments indicate that adult articular cartilage may show significant alterations in its histological, biochemical, and ultrastructural characteristics without disruption of the articular surface This model of articular cartilage "contusion" may represent a corollary to the joint damage that is observed following direct blunt trauma transmitted across articular surfaces without radiographic evidence of fracture The possibility that this form of injury may be the precursor of chondromalacic changes in patellar or femoral cartilage merits further study

Shark Cartilage Contains Inhibitors of Tumor Angiogenesis

Abstract: Shark cartilage contains a substance that strongly inhibits the growth of new blood vessels toward solid tumors, thereby restricting tumor growth. The abundance of this factor in shark cartilage, in contrast to cartilage from mammalian sources, may make sharks an ideal source of the inhibitor and may help to explain the rarity of neoplasms in these animals.

Matrix Vesicles in Atherosclerotic Calcification

Abstract: Matrix vesicles, small extracellular membranous structures, are known to be the initial loci of calcification of cartilage, bone, and dentin. Calcification is an important complication of atherosclerosis. Using histologic, ultrastructural, and cytochemical techniques, the present study has demonstrated that matrix vesicle-like structures are involved in the calcification of atherosclerotic lesions, as well as in arterial medial calcification. In aortas from autopsied humans and from rabbits and chickens on atherogenic diets, the matrix vesicles appear to be derived from intimal and medial cellular components, mainly smooth muscle cells.

The morphology of the calcification front in articular cartilage. Its significance in joint function

Abstract: Biochemical and histochemical studies have indicated that there is specific cellular activity in the region of the calcification front of articular cartilage implying that a regulation process takes place there. Using scanning and transmission electron microscopy and light microscopy to examine tissue sections of both undecalcified and decalcified articular cartilage in the region of the calcification front, we have looked at its morphology with particular reference to its cellular control. Our observations show that physiological calcification is an active process under cellular control and is related to the presence of extracellular membrane-bound matrix vesicles.

Growth hormone stimulates the proliferation of cultured chondrocytes from rabbit ear and rat rib growth cartilage

Abstract: The effect of growth hormone (GH) on various growth processes is generally considered to be indirect, mediated by GH-dependent plasma factors--somatomedins--which are produced mainly in the liver In vitro, somatomedins stimulate a number of processes that apparently are associated with cell growth It has been difficult, however, to induce skeletal growth by the administration of somatomedins in vivo Daily injections of a partially purified somatomedin preparation failed to induce accumulated longitudinal bone growth using the intravital marker tetracycline or by measuring the nose-to-tail length Administration of insulin-like growth factor I (IGF I) which is probably identical to somatomedin C, to hypophysectomized rats has been reported to increase the width of the epiphyseal plate But although this suggests an in vivo effect of IGF I on longitudinal bone growth, such an effect has not been directly demonstrated Recently, we reported that local administration of human GH (hGH) into the proximal cartilage growth plate of the tibia of hypophysectomized rats stimulated longitudinal bone growth on the side injected with the hormone Furthermore, we have identified specific binding sites for hGH in cultured chondrocytes from rabbit ear and epiphyses Here, we show that hGH, but not the structurally related polypeptides ovine prolactin or human prolactin, stimulates DNA synthesis in chondrocytes from rabbit ear and from rat rib growth plate, cultured in a chemically defined medium without the addition of serum Our results suggest that GH directly initiates proliferation in mammalian chondrocytes

The origins of osteochondromas and enchondromas. A histopathologic study.

Abstract: Histopathologic sections of large pieces of tissue obtained from both surgical and postmortem specimens of osteochondromas and enchondromas were analyzed to elucidate the pathogenesis of these two lesions. The osteochondroma is derived from aberrant cartilaginous epiphyseal growth plate tissue, which proliferates autonomously and separates from the normal growth plate near its edge. As growth progresses, the aberrant tissue remains in a subperiosteal location, where it may either disappear through remodeling or proliferate as an early osteochondroma perpendicular to the orientation of the growth plate from which it was derived. The enchondroma also is derived from the actively proliferating cartilaginous tissue of growth plates. For unknown reasons certain groups of chondrocytes do not proceed to undergo hypertrophy and death. As a result, a column of uncalcified cartilage extends from the underside of the growth plate into the region in which all other cartilaginous tissue has been remodeled into primary bone. The bridge to the plate may either remain intact or become interrupted by normal bone. An isolated group of chondrocytes may (1) be walled off from normal tissue by lamellar bone; (2) undergo calcification and secondary osseous remodeling, either in part or in total; or (3) proliferate as an intraosseous chondroma (benign enchondroma). A similar but not identical process of enchondroma formation may occur in fibrous dysplasia of bone, systemic growth plate dysplasias similar to achondroplasia, and osteogenesis imperfecta.

Collagenolytic activity and collagen matrix breakdown of the articular cartilage in the Pond-Nuki dog model of osteoarthritis.

Abstract: Recent reports on the Pond-Nuki model of osteoarthritis in the dog have provided evidence for partial disruption of the collagen network. The possibility of collagenase involvement in these localized changes was studied. Animals were killed 2, 4, 8, and 12 weeks after surgery. The left knee served as a sham-operated control. Cartilages from femoral condyles were processed for light and electron microscopy and assayed for collagenolytic activity by a direct tissue assay, based on the measurement of digestion of endogenous cartilage collagen. Animals killed at 2 and 4 weeks showed fibrillation and mild erosion of femoral condyles, which usually progressed to ulceration by 8 and 12 weeks. Electron microscopy demonstrated fiber disruption of the mid-zone perilacunar collagen as early as 2 weeks after the operation. Total collagenolytic activity, measured after activation by aminophenylmercuric acetate, was significantly higher in decreased cartilage than in controls of 2, 4, and 8 weeks; the peak value was at 4 weeks. Collagenase was shown, by its specific action on type I collagen, to be present at 2 and 4 weeks; however, other metalloproteases may also contribute to the digestion. The correlation between increased collagenolytic activity and the early osteoarthritic changes in cartilage suggests a role of this enzyme activity in the disease process.

Hypertrophic repair of articular cartilage in experimental osteoarthrosis.

Abstract: Section of the anterior cruciate ligament has been performed in the knee of 11 mature dogs. The macroscopically normal cartilage from patella and femoral trochlea of animals killed from 2 to 32 weeks after operation was used for histological, histomorphometrical, and biochemical analysis. Previously undescribed degenerative lesions of the superficial matrix were observed, and there was evidence for secondary healing of these lesions. An early and progressive decrease in superficial cell density and a later progressive increase in cartilage thickness without any change in the cell density of the middle and deep cartilage layers was found. A slight increase in water content with no reduction in glycosaminoglycan content was observed. The results suggest that joint laxity results initially in superficial degenerative changes and later in hypertrophic regenerative changes due to cell proliferation and increased matrix synthesis. Hypertrophic remodeling of articular cartilage in response to abnormal mechanical stresses is postulated.

Morphologic observations in the early phase of the cartilage-pannus junction

Abstract: The early phase of cartilage destruction by active cellular pannus in rheumatoid joints was observed under light and electron microscopy. In the early phase of pannus formation, cartilage was covered by several layers of fibroblast-like cells. This was also the case at the advancing edge of the pannus. Invasion of the cartilage by macrophage-like cells has been observed to start beneath this layer. Observations under electron microscope demonstrated that the main cells participating in the cartilage destruction at the cartilage-pannus junction were either fibroblast-like or macrophage-like cells, and suggested the possibility that these two types of cells were derived from synovial type A and type B cells. Morphologic observations also suggested a possibility of transformation of the fibroblast-like cell into the macrophage-like cell at the cartilage-pannus junction.

Growth of Cultured Cells Using Collagen as Substrate

Abstract: Publisher Summary This chapter discusses the growth of cultured cells using collagen as substrate. Collagen is a major constituent of the extracellular matrix in vivo and is used as a substrate for cultured cells. Collagen is a component of extracellular matrices and basement membrane. Collagen occurs in four chemically and genetically distinct forms: type I, found in bone, tendon, and skin; type II, found in cartilage and eye; type III, associated with type I in skin, blood vessels, and smooth muscle; and type IV, found in basement membranes. Collagen used as a substrate in culture work, in the form of either thin film of dried collagen or hydrated collagen gel, usually consists of type I found in acid extract of rat tail. Collagen enhances the growth of cultured cells more than the conventional plastic or glass culture dish. High adhesion collagen substrate enhances neuronal survival and neuritic outgrowth while slowing down non-neuronal proliferation. Three-dimensional expression of cultured mammary epithelial cells in the collagen gel matrix provides conditions such as those found in vivo for the study of mammogenesis, lactogenesis, and carcinogenesis. This culture system may be applied to the studies of transformation, morphology, and cloning of mammary epithelium, proliferation, and differentiation.

S-100 protein in tumors of cartilage and bone. An immunohistochemical study.

Abstract: Using the peroxidase-antiperoxidase (PAP) immunohistochemical method, S-100 protein was found in well-differentiated chondrocytes of chondroma, chondroblastoma, mesenchymal chondrosarcoma, and osteosarcoma. It was not detected in osteoma, osteoblastoma, giant cell tumor, and Ewing's tumor. The presence of S-100 protein in tumorous chondrocytes and chondroblasts suggests that this protein may be a marker of chondrocyte origin and should not be considered a specific marker for nerve tissue.

In vivo effect of aspirin on canine osteoarthritic cartilage

Abstract: The in vivo effect of aspirin on degeneration of knee cartilage in a canine model of osteoarthritis was examined. When dogs were fed aspirin daily after anterior cruciate ligament transection, the degeneration of articular cartilage in the unstable knee was more marked 9 weeks later than that in the operated knee of dogs which did not receive aspirin. Compared with samples from the contralateral knees, the thickness of articular cartilage in the operated knees of aspirin-fed dogs was reduced, while it was increased in the operated knees of dogs not fed aspirin. In addition, the proteoglycan (uronic acid) content and the augmentation of proteoglycan synthesis in cartilage from the unstable knee were significantly lower when the dogs were fed aspirin than when they were not, and Safranin-O staining of the matrix was less intense. However, cartilage from the contralateral knees of aspirin-fed dogs was histochemically and biochemically normal in every respect. When metatarsal bones, with their overlying articular cartilage intact, were cultured in the presence of 10−4M and 10−5M salicylate, net glycosaminoglycan synthesis was suppressed by 25% and 15%, respectively. These concentrations of salicylate had previously been shown to have no effect on glycosaminoglycan metabolism in normal cartilage from the weightbearing region of the femoral condyle. Since the uronic acid content of metatarsal cartilage is lower than that of femoral cartilage, and that of osteoarthritic femoral cartilage is lower than that of normal femoral cartilage, the present results are consistent with the concept that cartilage is more permeable to aspirin when its matrix is depleted of proteoglycans.

The potential aggressiveness of synovial tissue in rheumatoid arthritis.

Abstract: Operation specimens of articular tissue from about 8000 patients with clinically evident rheumatoid arthritis have been studied by light microscopy and in 583 cases by electron microscopy over a period of several years. We examined the tissue in closest contact with eroded cartilage. In approximately 70 per cent. of cases this was a fibrous pannus of compact collagenous connective tissue with few fibrocytes; in approximately 25 per cent. of cases a pannus, consisting of loose granulation tissue, moderately rich in collagen fibres, fibroblasts, and small blood vessels; in approximately 5 per cent. of cases, however, we found, that the zone in close contact consisted of uniform layers of immature-looking synovial cells with large nuclei. These immature-looking cells encroach on the cartilage from the junction of synovium with the articular cartilage. The development of these aggressive cell structures seemed to be preceded by a fibrinous inflammatory exudate. The cells contain lysosomal enzymes which are able to destroy prcteoglycans and collagen fibres and could therefore be the basis of erosion of cartilage. The cell structures seem to be short-lived and they are avascular at least initially. Most of the cells seem to die within a few days. The remaining cells assume the appearance of fibroblasts and form the later pannus. The cell content decreases as the pannus gets older. It is suggested that the destruction of articular cartilage takes place only during the short time in which these aggressive cell structures are present. The erosive synovial cells may however reappear during the intermittent course of the disease, after episodes of quiescence and acute inflammation.

Closure of osteochondral lesions using chondral fragments and fibrin adhesive.

Abstract: In 75 knee joints of 46 adult rabbits osteochondral defects of 4 mm diameter were placed by a drill reaching the cancellous bone. Twenty-three defects were left untreated, or closed by collagen foam or fibrin adhesive, or a combination of both. Fifty-two defects were closed with very small autologous cartilage fragments and a special fibrin adhesive. The adhesive differed from commercially supplied types by digested alpha chain of fibrinogen for increase in concentration, and by the addition of alpha-2-macroglobulin as protease-inhibitor. In most cases small pieces of collagen foam were added for hemostasis. In the first group of 23 joints observed over up to 40 weeks, no hyaline cartilage was found histologically in any of the defects. In the second group a rapid proliferation of chondrocytes appeared with development of hyaline cartilage with alcianblue-positive matrix. It resembled juvenile cartilage in its histologic appearance and with regard to the induction of ossification. The phenomenon is interpreted as a "second adolescence" of the adult cartilage induced by the rich nutritional and oxygen supply from the cancellous vessels, which resembles the environmental conditions before the forming of subchondral cortical bone at the end of the growth period. This method enabled us to achieve a complete closure of defects by hyaline cartilage on the very level of the surrounding articular surface.

Interaction of polymorphonuclear leukocytes with immune complexes trapped in rheumatoid articular cartilage

Abstract: When rheumatoid articular cartilage samples were incubated with normal polymorphonuclear leukocytes (PMN) in vitro, large numbers of PMN were seen attached to the articular surface. As observed by electron microscopy, significant numbers of these cells invaded the cartilage tissue and phagocytosed amorphous material which presumably contained immune complexes. In control cartilage from osteoarthritic, pyogenic, and normal subjects, only a few PMN were attached to the articular surface after incubation with PMN. These results demonstrate that immune complexes trapped in the superficial region of the rheumatoid articular cartilage may play an important role in the destruction of cartilage by the release of lysosomal enzymes from PMN.

in vitro transformation of chondroprogenitor cells into osteoblasts and the formation of new membrane bone

Abstract: Mandibular condyles of fetal mice 19 to 20 days in utero were kept in an organ culture system for up to 10 days. After 2 days in culture the cartilage of the mandibular condyle appeared to have maintained all its inherent structural characteristics, including its various cell layers: chondroprogenitor, chondroblastic, and hypertrophic. After 5 days in culture no chondroblasts could be seen and, instead, the entire cartilage was occupied by hypertrophic chondrocytes. At the same time, the mesenchymal cells at the chondroprogenitor zone differentiated with osteoblasts which produced osteoid. Light microscopic examinations showed that the newly formed osteoid did not stain with acidic toluidine blue or with alcian blue, but stained intensively with the van Gieson stain and with Periodic acid-Schiff (PAS). The osteoid reacted with antibodies against type I collagen but not with antibodies against type II collagen. Electron microscopic examinations showed that the mineralization appeared to be associated with collagen fibers in bone rather than with matrix vesicles in the cartilage. The process of bone formation progressed with time and by the 10th day new bone replaced almost the entire cartilage, thus forming an expanded layer of membrane bone. This in vitro system represents an experimental model whereby undifferentiated precursor cells transform into osteoblasts with the subsequent formation of a typical membrane bone.

Legg-Calvé-Perthes disease. Histochemical and ultrastructural observations of the epiphyseal cartilage and physis.

Abstract: Biopsy specimens of the lateral aspect of the femoral head and neck were obtained from five children with Legg-Calve-Perthes disease and were studied using histochemistry and electron microscopy. Beneath the normal articular cartilage there was a thick zone of hyaline (epiphyseal) cartilage containing sharply demarcated areas of hypercellular and fibrillated cartilage with prominent blood vessels. The fibrillated cartilage was strongly positive to alcian blue, weakly positive to periodic acid-Schiff, and positive to aniline blue. The interterritorial matrix in the hypercellular areas was weakly positive to both alcian blue and periodic acid-Schiff. Ultrastructural examination of these areas revealed many irregularly oriented large collagen fibrils and variable amounts of proteoglycan granules. These results suggest that in the fibrillar areas there are: (1) a high proteoglycan content, (2) a decrease in structural glycoproteins, and (3) a different size of collagen fibrils from that of normal epiphyseal cartilage. The hypercellular areas had a decrease in proteoglycans, glycoproteins, and collagen. The lateral physeal margin was often irregular, with a marked reduction of collagen and proteoglycan granules, and contained numerous large lipid inclusions. CLINICAL RELEVANCE: The abnormal areas in the epiphyseal cartilage of patients with Legg-Calve-Perthes disease have different histochemical and structural properties from normal cartilage and from fibrocartilage. This suggests that the disease could be a localized expression of a generalized, transient disorder of epiphyseal cartilage that is responsible for delayed skeletal maturation. The cartilage lesions are similar to those seen in the vertebral plates in patients with juvenile kyphosis. Whether the epiphyseal cartilage abnormalities are primary or are secondary to ischemia remains uncertain; however, it appears that the collapse and necrosis of the femoral head could result from the breakdown and disorganization of the matrix of the epiphyseal cartilage, followed by abnormal ossification.

Bacterial lipopolysaccharides induce in vitro degradation of cartilage matrix through chondrocyte activation.

Abstract: The present studies demonstrate that bacterial lipopolysaccharides (LPS) induce cartilage matrix degradation in live explants in organ culture. Quintuplicate bovine nasal fibrocartilage explants cultured for 8 d with three different purified LPS preparations derived from Escherichia coli and Salmonella typhosa at concentrations ranging from 1.0 to 25.0 micrograms/ml resulted in matrix proteoglycan depletion of 33.3 +/- 5.8 to 92.5 +/- 2.0% (medium control depletion 17.7 +/- 0.7 to 32.4 +/- 1.4%). Matrix degradation depended on the presence of live chondrocytes because frozen-thawed explants incubated with LPS failed to show any proteoglycan release. Moreover, the addition of Polymyxin B (25 micrograms/ml) to live explants incubated with LPS abolished matrix release, whereas Polymyxin B had no effect on the matrix-degrading activity provided by blood mononuclear cell factors. A highly purified Lipid A preparation induced matrix degradation at a concentration of 0.01 micrograms/ml. Cartilage matrix collagen and proteoglycan depletion also occurred with porcine articular cartilage explants (collagen release: 18.3 +/- 3.5%, medium control: 2.1 +/- 0.5%; proteoglycan release: 79.0 +/- 5.9%, medium control: 28.8 +/- 4.8%). Histochemical analysis of the cultured explants confirmed the results described above. Gel chromatography of the proteoglycans released in culture indicated that LPS induced significant degradation of the high molecular weight chondroitin sulfate-containing aggregates. These findings suggest that bacterial products may induce cartilage damage by direct stimulation of chondrocytes. This pathogenic mechanism may play a role in joint damage in septic arthritis and in arthropathies resulting from the presence of bacterial products derived from the gastrointestinal tract.

Age-related changes in the structure of proteoglycan link proteins present in normal human articular cartilage.

Abstract: Link proteins were identified immunologically in human articular-cartilage protein preparations from various individuals. Irrespective of age, all cartilages contained three link proteins of mol.wts. 48000, 44000 and 41000. However, with increasing age, multiple additional components of mol.wts. 26000-30000 were commonly observed under conditions where disulphide bonds were reduced.