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PubMedDate not supplied

Macroscopically normal cartilage from the human osteoarthritic femoral head. II. Measurement of cartilage thickness and cell density.

Cell density and thickness of macroscopically "normal" cartilage from 32 osteoarthritic (OA) femoral heads removed surgically have been studied by using histomorphometry. The results have been interpreted with special reference to qualitative aspects of regions analyzed at a microscopic level. OA cartilage with a microscopically normal appearance have a normal cell content and thickness except for the region adjacent to the zone of cartilage cleavage where a significant reduction in superficial cell density was found. OA cartilage showing middle tissue layer lesions such as unmasked fibers was characterized by an almost normal cellularity but a significantly increased tissue thickness.

Cartilage↗
PubMed1995

Interleukin-4, an inhibitor of cartilage breakdown in bovine articular cartilage explants.

OBJECTIVE: To determine the ability of interleukin-4 (IL-4) to inhibit the degradation of proteoglycan in bovine articular cartilage explants stimulated by human interleukin-1 (IL-1 alpha), tumor necrosis factor (TNF-alpha), a combination of TNF-alpha and IL-1 alpha, and lipopolysaccharide (LPS). METHODS: 35SO4 radiolabelled bovine radiocarpal cartilage explants were treated with IL-1 alpha, TNF-alpha, TNF-alpha plus IL-1 alpha, or LPS, plus various concentrations of IL-4 for 72 h. Proteoglycan released to the media was analyzed by scintillation counting and composite gel electrophoresis. Media samples were also analyzed by Western immunoblotting for metalloproteinases and TIMP. RESULTS: IL-4 significantly reduced the cartilage proteoglycan degradation induced by IL-1 alpha, TNF-alpha, TNF-alpha plus IL-1 alpha, or LPS (50% inhibitory concentration, IC50 for IL-4 ranged from about 15 to 50 ng/ml). Western blotting showed that media stromelysin levels were increased by IL-1 alpha, TNF-alpha, and LPS, but that IL-4 had no observable effect. Composite gel electrophoresis demonstrated quantitative and qualitative differences in proteoglycan degradation after IL-4 treatment. CONCLUSION: IL-4 has a potent inhibitory effect on cartilage degradation after stimulation with IL-1 alpha, TNF-alpha, TNF-alpha plus IL-1 alpha, or LPS. These results suggest that IL-4 should be investigated further for therapeutic value as a chondroprotective agent for the treatment of arthritis.

Animals↗
PubMed1982

[Transplantation of isolated chondrocytes in articular cartilage defects. Regeneration of adult hyaline cartilage with fetal chondrocytes].

Viability and proliferative capacity of the chondrocytes are particularly important for a successful cartilage graft. This can be demonstrated by a new in vitro colony-forming assay. Only fetal or neonatal chondrocytes are considered to be applicable according to these criteria. Single cell suspensions prepared from articular cartilage can be transplanted without technical problems. In animal experiments articular cartilage regenerated after transplantation of neonatal chondrocytes, whereas only connective tissue was found in controls.

Adult↗
PubMed2005

Long-term in vivo stability of rabbit nasal septal cartilage following laser cartilage reshaping: a pilot investigation.

BACKGROUND AND OBJECTIVES: To evaluate the long-term effect of laser cartilage reshaping on rabbit nasal septal cartilage viability and mechanical integrity in an in vivo model. STUDY DESIGN/MATERIALS AND METHODS: In vivo animal investigation. Rabbit septal cartilage specimens were laser (Nd:YAG, lambda = 1.32 mum, spot size 5.4-mm diameter, 10 W, 10 seconds, 50 Hz PPR) reshaped and subsequently reimplanted into an interscapular subcutaneous pocket. Specimens were harvested at 8 and 12 months and evaluated using photography, flow cytometry, and histology. RESULTS: Grossly, specimens showed alteration in the physical integrity with varying degrees of tissue resorption. The non-irradiated control specimens demonstrated significantly increased stiffness. Histologically, there was marked depletion of the extracellular matrix and an overall reduction in tissue mass in laser irradiated tissues. However, flow cytometry data identified viable chondrocytes in laser-irradiated specimens that were identical to those observed in controls. CONCLUSIONS: Study results demonstrate that the rabbit nasal septal cartilage model can be effectively used to study laser reshaping, however alternative recipient sites with perichondrial lining, such as the pinna, may provide a more realistic physiologic environment for reshaped graft tissue. The dosimetry used in this pilot study likely led to significant thermal injury. Study results underscore the importance of elucidating the optimal laser dosimetry required to initiate permanent shape change while minimizing thermal damage.

Animals↗
PubMedDate not supplied

The porcine and lagomorph septal cartilages: models for tissue engineering and morphologic cartilage research.

Interest in reconstruction and modification of the facial cartilaginous frameworks using advanced technology and instrumentation is growing rapidly. Despite this maturing interest, no animal model has been established to provide morphologic cartilage tissue with similar characteristics to human septum in suitable quantities. The objective of this study was to characterize porcine and lagomorph (rabbit) nasal septal cartilage tissue. Both models share great similarity with their human counterpart and provide a low-cost, high-volume, and easily obtained source of bulk cartilage tissue. We present a technique for harvesting intact septal cartilages from these species, and characterize select cellular, metabolic, and physical properties using pulse-chase radiolabeling, flow cytometry, and mechanical analysis. Our selective evaluation of key tissue properties establishes these species as appropriate animal models for nasal septal cartilaginous surgery.

Animals↗
PubMed1997

Small fragments of cartilage oligomeric matrix protein in synovial fluid and serum as markers for cartilage degradation.

We determined the tissue distribution of cartilage oligomeric matrix protein (COMP) in man and evaluated COMP in synovial fluid (SF) and serum. COMP was purified from human articular cartilage. Polyclonal antibodies were used to detect COMP in tissue cryosections and protein extracts. COMP was determined quantitatively and qualitatively in SF and serum by competitive enzyme-linked immunosorbent assay and immunoblotting. Knee joint SF was taken from nine cadaveric and six living controls, 52 patients with osteoarthritis (OA), 85 patients with rheumatoid arthritis (RA) and 60 patients with other forms of inflammatory arthritis. The degradative potential of SF on native COMP was tested in vitro. The highest concentrations of COMP were measured in articular cartilage and meniscus, the lowest in rib and trachea. Compared with controls, the concentrations of COMP in SF and serum were elevated in 36 and 50% of the patients. A total of 84% of patients with RA and 60% of patients with other forms of inflammatory arthritis showed significant amounts of low-molecular-weight COMP fragments (50-70 kDa) in SF. In contrast, SF fragments were present in only 21% of the OA patients. Furthermore, 13% of SF taken from patients with RA or other forms of inflammatory arthritis were able to degrade COMP in vitro. Using inhibitors, the involvement of serine proteinases could be demonstrated in only 8% of the cases. Based on these results, the absolute levels of COMP in SF and serum, and its fragmentation pattern in SF, seem to be promising as markers of joint tissue metabolism.

Adult↗
PubMed1978

Effect of cartilage bone-marrow extract on articular cartilage collagen formation.

Cartilage bone-marrow extract has stimulated the collagen formation of articular as well as sternal cartilage collagen in chick embryo. Collagen biosynthesis has been stimulated also in other investigated tissues, i.e. in cornea and sclera of chick embryo as well as in sponge granuloma of rats, where mainly formation of collagen type I was stimulated. Glycosaminoglycans formation has also been increased after administration of cartilage bone-marrow extract.

Animals↗
PubMed1995

Cartilage and bone metabolism in rheumatoid arthritis. Differences between rapid and slow progression of disease identified by serum markers of cartilage metabolism.

Serum concentrations of specific cartilage and bone molecules reflecting tissue turnover were measured in two well-defined patient groups with early rheumatoid arthritis with distinctly different disease outcome to see if early differences in their levels are prognostic of the rate of joint destruction. Compared with a matched normal population, increased concentrations of cartilage oligomeric matrix protein (COMP) were found in all patients who developed rapid hip joint destruction. In contrast, levels of a putative marker of cartilage aggrecan synthesis, the chondroitin sulfate epitope 846, were increased only in patients with slow joint destruction. Levels of bone sialoprotein (BSP) were increased in both groups, as were levels of the C-propeptide of type II procollagen (CPII), a marker of collagen II synthesis. The increased concentrations of the 846 epitope in patients with slow joint destruction suggest increased aggrecan synthesis. The low levels of the 846 epitope in patients with rapid joint destruction, concomitant with elevated levels of CPII, suggest a selective increase in collagen synthesis. The elevated BSP levels indicate an increased bone turnover in both groups. Thus elevated serum levels of COMP may indicate an unfavorable prognosis for rapid joint destruction, whereas elevated 846 epitope indicates a more favorable prognosis.

Adult↗
PubMed2004

[Tissue engineered cartilage for biological repair of cartilage defects].

Recent developments in tissue engineering techniques in cartilage repair were discussed. Recently, the novel two-step method, the alginate-recovered-chondrocyte method (ARC method), which does not require the aid of an exogenous synthetic matrix, was developed. The first step of this method consists of culturing phenotypically stable chondrocytes under conditions optimal for the formation of a proteoglycan-rich cell-associated matrix (CM) in alginate beads. Then, the cells with their CM are recovered from the alginate and allowed to rapidly integrate into a solid mass of tissue on a culture insert with a porous membrane. The use of a growth factor, recombinant human osteogenic protein-1 (OP-1) maximized the formation of tissue engineered cartilaginous tissue from adult human articular cartilage. Using the ARC method, the enhancement of matrix formation by OP-1 will produce a larger volume of tissue-engineered cartilage to cover large defects.

Activin Receptors, Type I↗
PubMedDate not supplied

Local hyperthermia and cartilage breakdown: histochemical and metabolic studies on rabbit articular cartilage in vitro.

The hypothesis that local hyperthermia generated in inflamed joints may cause damage to the articular cartilage was tested in vitro using histochemical and isotopic methods. We found that this could be the case. Incubation temperatures above 38 degrees C in experiments of longer duration and 39 degrees C during shorter incubation times induced a loss of metachromasia, decreased rates of synthesis, and increased degradation of cartilage matrix macromolecules. It is postulated that local synovial hyperthermia might partly account for the cartilage degeneration that frequently occurs in rheumatoid arthritis as a result of a decreased synthesis and increased catabolism of matrix macromolecules.

Animals↗
PubMed1999

Correlation of laminated MR appearance of articular cartilage with histology, ascertained by artificial landmarks on the cartilage.

The object of this study was to correlate the laminae of articular cartilage on magnetic resonance (MR) imaging with histologic layers. T1- and fast spin-echo T2-weighted images of articular cartilage with artificial landmarks were obtained under high gradient echo strength (25 mT/m) conditions and a voxel size of 78 x 156 x 2000 microm. Images were also obtained with a) changed frequency-encoding directions; b) changed readout gradient strength; and c) a varied number of phase-encoding steps. T2 mapping was performed with angular variations. Artificial landmarks allowed accurate comparison between the laminae on MR images and the histologic zones. No alterations of the laminae were noted by changing the frequency gradient direction. Altering readout gradient strengths did not show a difference in the thickness of the laminae, and increasing the phase-encoding steps resulted in a more distinct laminated appearance, ruling out chemical shift, susceptibility, and truncation artifacts. The T2 mapping profile showed an anisotropic angular dependency from the magic angle effect. In conclusion, the laminated appearance of articular cartilage on spin-echo and fast spin-echo MR images correlated with the histologic zones rather than MR artifacts.

Animals↗
PubMed1979

Articular cartilage preservation and storage. II. Mechanical indentation testing of viable, stored articular cartilage.

Mature rabbit articular cartilage in the form of distal femoral condyles, composite osteoarticular structures, were incubated in the presence of alpha-tocopherol (200 micrograms/ml) over a period of time. Indentation testing and 35S uptake indicate preservation of sustained load carrying capacity and viability, respectively, in the presence of alpha-tocopherol for up to 30 days in organ culture. Condylar cartilage stored in the absence of alpha-tocopherol as well as frozen cartilage demonstrated progressive inability to resist sustained loading over time. Nonoptimal synthetic function apparently occurred in these latter two groups when compared to alpha-tocopherol stored material.

Animals↗
PubMed1987

Immunity to cartilage proteoglycans in BALB/c mice with progressive polyarthritis and ankylosing spondylitis induced by injection of human cartilage proteoglycan.

Intraperitoneal injection of human fetal cartilage proteoglycan (depleted of chondroitin sulfate) in Freund's complete or incomplete adjuvant induces a chronic erosive polyarthritis and spondylitis in all female BALB/c mice. This occurrence is strain-specific but not haplotype-specific, and it is sex-related. The development of the arthritis is associated with the natural presence of cellular immunity to the immunizing antigen and to chondroitinase ABC-treated mouse cartilage proteoglycan. In addition, relatively more antibody to the immunizing proteoglycan is elicited in arthritic mice, and antibodies are produced that cross-react with native mouse proteoglycan. This combination of immune responses is not observed in mice that do not develop arthritis. Associated with the arthritis is the development of cytotoxicity to mouse chondrocytes and, in some animals, of rheumatoid factor, immune deposits in joint tissues and kidneys, and the production of autoantibodies to mouse type II collagen. These observations might be related to our earlier demonstration that immunity to human cartilage proteoglycan is observed in some patients with ankylosing spondylitis.

Adult↗
PubMed1988

Evidence that a humoral immune response to autologous cartilage proteoglycan can participate in the induction of cartilage pathology.

We examined antiproteoglycan antibodies as an autoimmune response for induction of synovitis. This hypothesis was studied by monitoring humoral antiproteoglycan antibody following IgG induction of experimental immune synovitis, localization in the articular cartilage of an autologous immune response, and loss of proteoglycan from cartilage following intravenous administration of antiproteoglycan monoclonal antibodies. The data support the hypothesis that autoimmunity to cartilage macromolecules may play a role in the etiopathogenesis of arthritis.

Animals↗
PubMed2004

Synthesis of proteoglycan 4 by chondrocyte subpopulations in cartilage explants, monolayer cultures, and resurfaced cartilage cultures.

OBJECTIVE: To quantify the levels of proteoglycan 4 (PRG4) expression by subpopulations of chondrocytes from superficial, middle, and deep layers of normal bovine calf cartilage in various culture systems. METHODS: Bovine calf articular cartilage discs or isolated cells were used in 1 of 3 systems of chondrocyte culture: explant, monolayer, or transplant, for 1-9 days. PRG4 expression was quantified by enzyme-linked immunosorbent assay of spent medium and localized by immunohistochemistry at the articular surface and within chondrocytes in explants and cultured cells. RESULTS: Superficial chondrocytes secreted much more PRG4 than did middle and deep chondrocytes in all cultures. The pattern of PRG4 secretion into superficial culture medium varied with the duration of culture, decreasing with time in explant culture (from approximately 25 microg/cm(2)/day on days 0-1 to approximately 3 microg/cm(2)/day on days 5-9), while increasing in monolayer culture (from approximately 1 pg/cell/day on days 0-1 to approximately 7 pg/cell/day on days 7-9) and tending to increase in transplant culture (reaching approximately 2 microg/cm(2)/day by days 7-9). In all of the culture systems, inclusion of ascorbic acid stimulated PRG4 secretion, and the source of PRG4 was immunolocalized to superficial cells. CONCLUSION: The results described here indicate that the phenotype of PRG4 secretion by chondrocytes in culture is generally maintained, in that PRG4 is expressed to a much greater degree by chondrocytes from the superficial zone than by those from the middle and deep zones. The marked up-regulation of PRG4 synthesis by ascorbic acid may have implications for cartilage homeostasis and prevention of osteoarthritic disease. Transplanting specialized cells that secrete PRG4 to a surface may impart functional lubrication and be generally applicable to many tissues in the body.

Animals↗
PubMed1984

Labeling of articular cartilage surface with cationized ferritin: aged human normal and osteoarthritic cartilage.

The labeling of the articular surface with cationized ferritin (CF), an electron-dense marker, visualizes the anionic sites and may disclose abnormal penetration of the large CF molecule into the subsurface layers. Various areas of cartilage selected by unaided eye examination were taken from femoral heads excised in three cases of osteoarthritis and two cases of hip fracture. The fragments were examined by optical microscopy and by electron microscopy after labeling with CF. The labeling with and the penetration of CF were correlated with the morphological features of the surface. The surfaces belonging to the erosion border were disrupted and the CF penetrated approximately 2 microns into the matrix along the collagen fibers and in areas containing a patchy dense material. Prefixation with Karnovsky's fixative prevents CF penetration. The fragments taken at a distance from the erosion border showed at electron microscopical examination either an intact appearance of the surface that was labeled without penetration or a disrupted surface with penetration of the label. The osteophytes and the regeneration buds surface were labeled showing little or no penetration. The fragments from cartilage of hip fractures had either an intact surface regularly labeled or a slightly or moderately disrupted surface with moderate penetration of CF. The penetration of large molecules of CF in damaged cartilage demonstrates important permeability changes that may be significant for the pathogenetic mechanism of osteoarthritis. Similar permeability changes were previously shown in mice femoral heads treated in vitro with collagenase or trypsin and labeled with CF.

Age Factors↗
PubMed1987

Chondrons in cartilage: ultrastructural analysis of the pericellular microenvironment in adult human articular cartilages.

A combination of scanning and transmission electron microscopy was used to investigate the morphology and ultrastructure of normal human articular cartilage sampled from adult amputation specimens. This study confirms our previous observations on canine articular cartilage, which showed middle and deep layer chondrocytes surrounded by a pericellular matrix and enclosed within a pericellular capsule composed of filamentous and fine fibrillar materials. Pores in the "felt-like" organization of the capsular weave progressively decreased in size from the inner to the outer border of the capsule. Matrix vesicles were found embedded within the capsular weave and distributed throughout the territorial matrix. It is suggested that the chondrocyte, its pericellular matrix, and capsule together constitute the "chondron," a primary functional and metabolic unit of cartilage that acts hydrodynamically to protect the integrity of the chondrocyte and its pericellular microenvironment during compressive loading.

Adult↗
PubMed1994

Cross-validation of cyanogen bromide-peptide ratios to measure the proportion of type II collagen in pepsin digests of equine articular cartilage, meniscus, and cartilage repair tissue.

Collagen type I and type II were purified from equine flexor tendon and articular cartilage, respectively. Equal amounts of these collagens were cleaved with cyanogen bromide, and 11 mixtures containing increasing proportions of type II collagen were separated in seven identical sodium dodecyl sulfate-polyacrylamide gels. The density of bands was measured in wet gels and the peak areas were used to form six ratios of peptide bands that had polynomial relationships with the known proportions of type I and type II collagen in the mixtures. Calibration curves for determining the proportion of type II collagen in the mixtures were constructed using ratios and combinations of ratios of peak areas. Cross-validation was used to identify calibration curves with the smallest squared prediction error or squared average prediction error for all combinations of ratios. Ratios of peak areas of each one of the seven gels were treated, in turn, as the "unknown," and a prediction was carried out using these unknowns and the ratios from the other six gels. Two ratios had the smallest squared average prediction error and calibration curves were computed for these ratios with all seven gels. These curves were used to estimate the proportion of type II collagen in the pepsin-soluble and the pepsin-resistant fractions of articular cartilage inner and outer meniscus, and cartilage repair tissue. Cross-validation enabled selection of the cyanogen bromide-peptide ratios for calibration curves that resulted in the most accurate estimation of the proportion of type II collagen in pepsin digests of tissues.

Animals↗