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At least 127 records · Page 7Linked to original sources
PubMed1976

Metabolic recovery of articular cartilage after intra-articular injections of glucocorticoid.

The recovery of adult rabbit articular cartilage after nine weekly intra-articular injections of hydrocortisone acetate was investigated using biochemical, autoradiographic, and tracer methods. After the cessation of steroid injections, the rates of synthesis of proteoglycans and collagen increased by up to 900 per cent. The increase occurred because of accelerated metabolism of existing cells and an increase (caused by mitosis) in the number of functioning chondrocytes. The proteoglycan concentration only returned to normal values after six months.

Animals↗
PubMed1991

Osteoarthritis of the trapeziometacarpal joint: the pathophysiology of articular cartilage degeneration. II. Articular wear patterns in the osteoarthritic joint.

An anatomic and radiographic study of the osteoarthritic trapeziometacarpal joint was conducted on 27 surgical specimens harvested during basal joint arthroplasty. Surface wear patterns were analyzed by hyaline cartilage staining, and relative involvement of trapezium and metacarpal was calculated as the trapezium/metacarpal eburnation ratio. Eburnation occurred only on facing trapeziometacarpal surfaces in contact areas of the palmar compartment. Metacarpal degeneration began at the palmar joint margin adjacent to the beak ligament and extended dorsally, while trapezial degeneration originated on the central palmar slope and spread centrifugally with more advanced disease. Eburnation consistently involved a greater surface area on the trapezium than on the metacarpal in a ratio of nearly 3:1. A decreasing trapezium/metacarpal eburnation ratio correlated closely with worsening radiographic stage. These observations suggest translation of metacarpal on trapezium in the production of arthritic surface lesions and support a hypothesis of pathologic joint instability as the cause of trapeziometacarpal osteoarthritis.

Carpal Bones↗
PubMed1984

Embryonic chick cartilage collagens. Differences in the low-Mr species present in sternal cartilage and tibiotarsal articular cartilage.

The collagenous polypeptides present in embryonic chick sternal and tibiotarsal cartilages have been solubilised by digestion with pepsin and separated by salt fractionation. Type II collagen, 1 alpha 2 alpha 3 alpha collagen, and two polypeptides (apparent molecular mass 150 and 42 kDa), which were reducible to a number of smaller peptides, were extracted from both tissues. However, also present in the peptic digests of tibiotarsal cartilages was a major non-reducible highly-soluble polypeptide of 45 kDa. This short-chain collagen is apparently identical to the pepsinized product of G collagen (Mr 59 000), a major low-Mr procollagen-like species previously detected in chick chondrocyte cultures.

Amino Acids↗
PubMed1996

Delayed articular cartilage slough: two cases resulting from holmium:YAG laser damage to normal articular cartilage and a review of the literature.

We present two cases referred from other physicians with chondral damage and cartilage slough secondary to use of the holmium:YAG laser during knee arthroscopy. The first patient had a partial lateral meniscectomy, which was done with a 20-W Ho:YAG laser. The patient never fully recovered and underwent a second arthroscopy that revealed full-thickness cartilage defects of the lateral femoral condyle. The second patient had debridement of Outerbridge grade III changes of the lateral tibial plateau and patella, as well as a partial lateral meniscectomy using a Ho:YAG laser. The patient developed recurrent symptoms, and when a second arthroscopy was performed, new degenerative changes to the lateral femoral condyle were noted with large areas of cartilage loss. A careful look needs to be taken at the limited use of lasers until further randomized prospective studies are carried out comparing patient outcomes, cost, and long-term complications.

Adult↗
PubMed2003

Mechanical anisotropy of the human knee articular cartilage in compression.

Articular cartilage exhibits anisotropic mechanical properties when subjected to tension. However, mechanical anisotropy of mature cartilage in compression is poorly known. In this study, both confined and unconfined compression tests of cylindrical cartilage discs, taken from the adult human patello-femoral groove and cut either perpendicular (normal disc) or parallel (tangential disc) to the articular surface, were utilized to determine possible anisotropy in Young's modulus, E, aggregate modulus, Ha, Poisson's ratio, v and hydraulic permeability, k, of articular cartilage. The results indicated that Ha was significantly higher in the direction parallel to the articular surface as compared with the direction perpendicular to the surface (Ha = 1.237 +/- 0.486 MPa versus Ha = 0.845 +/- 0.383 MPa, p = 0.017, n = 10). The values of Poisson's ratio were similar, 0.158 +/- 0.148 for normal discs compared with 0.180 +/- 0.046 for tangential discs. Analysis using the linear biphasic model revealed that the decrease of permeability during the offset compression of 0-20 per cent was higher (p = 0.015, n = 10) in normal (from 25.5 x 10(-15) to 1.8 x 10(-15) m4/N s) than in tangential (from 12.3 x 10(-15) to 1.3 x 10(-15) m4/N s) discs. Based on the results, it is concluded that the mechanical characteristics of adult femoral groove articular cartilage are anisotropic also during compression. Anisotropy during compression may be essential for normal cartilage function. This property has to be considered when developing advanced theoretical models for cartilage biomechanics.

Adult↗
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↗
PubMed2006

Autologous cartilage implantation for full thickness articular cartilage defects of the knee.

BACKGROUND: Treatments for managing articular cartilage defects of the knee, including drilling and abrasion arthroplasty, are not always effective. When they are, long-term benefits may not be maintained and osteoarthritis may develop, resulting in the need for a total knee replacement. An alternative is the surgical implantation of healthy cartilage cells into damaged areas (autologous cartilage implantation). OBJECTIVES: To determine the effectiveness of autologous cartilage implantation (ACI) in people with full thickness articular cartilage defects of the knee. SEARCH STRATEGY: We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (15 December 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2005), MEDLINE (1966 to December 2005), CINAHL (1982 to December Week 2, 2004), EMBASE (1988 to 2005 Week 50), SPORTDiscus (1830 to January 2005) and the National Research Register Issue 3, 2005. SELECTION CRITERIA: Randomised and quasi-randomised trials comparing ACI with any other type of treatment (including no treatment or placebo) for symptomatic cartilage defects of the medial or lateral femoral condyle, femoral trochlea or patella. DATA COLLECTION AND ANALYSIS: Two review authors selected studies for inclusion independently. We assessed study quality based on adequacy of the randomisation process, adequacy of the allocation concealment process, potential for selection bias after allocation and level of masking. Data was not pooled due to clinical and methodological heterogeneity in the studies. MAIN RESULTS: We included four randomised controlled trials (266 participants). One trial of ACI versus mosaicplasty reported statistically significant results for ACI at one year, but only in a post-hoc subgroup analysis of participants with medial condylar defects; 88% had excellent or good results with ACI versus 69% with mosaicplasty. A second trial of ACI versus mosaicplasty found no statistically significant difference in clinical outcomes at two years. There was no statistically significant difference in outcomes at two years in a trial comparing ACI with microfracture. In addition, one trial of matrix-guided ACI versus microfracture did not contain enough long-term results to reach definitive conclusions. AUTHORS' CONCLUSIONS: The use of ACI and other chondral resurfacing techniques is becoming increasingly widespread. However, there is at present no evidence of significant difference between ACI and other interventions. Additional good quality randomised controlled trials with long-term functional outcomes are required.

Cartilage, Articular↗
PubMed1990

Biochemical analysis of normal articular cartilage in horses.

Articular cartilage specimens from the distal articular surface of 32 radiocarpal bones from 24 2- to 5-year-old horses were analyzed. The total collagen content was determined on the basis of the 4-hydroxyproline content, using a colorimetric method. A method for estimating the proportions of types-I and -II collagen by measuring spectrophotometric densities of specific cyanogen bromide peptide bands from mixtures of types-I and -II collagen on sodium dodecyl sulfate-polyacrylamide gels was used. The cyanogen bromide peptides representative of each collagen types-I and -II were identified. The peptide ratios were then computed for each of several standards of type-I and -II mixtures. A standard curve was derived from the correlation between these ratios and the corresponding proportions of type-II collagen in standard mixtures. Galactosamine and glucosamine content (hexosamines) were measured by ion chromatography. The galactosamine-to-glucosamine ratio, chondroitin sulfate and keratan sulfate values, and total glycosaminoglycan content were derived from the measured hexosamine content. The total collagen content averaged 556 mg/g (55.6 mg/100 mg) of tissue (dry weight, [dw]). Type-II collagen was the major collagen type in normal articular cartilage specimens. The ratio of the area under the alpha 1 (II)CB10 peak to the area under the alpha 1 (I)CB 7,8 + alpha 1 (II)CB11 peak was a second-order polynomial function of the proportion of type-II collagen in the specimens. The mean galactosamine and glucosamine content were 20.6 mg/g and 7.9 mg/g (dw), respectively. The mean galactosamine-to-glucosamine ratio was 3.74 +/- 0.62.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

Immunofluorescence localization of type-M collagen in articular cartilage.

Normal mammalian articular cartilage has been found to contain several collagenous peptide chains in addition to type-II collagen. We now report the distribution in adult pig cartilage of one of these new peptides, type-M collagen, using type-specific antibodies. Type M is primarily located in the pericellular environment of the cells in the deeper zones of the articular cartilage. The distribution is shown to be distinct from that of type-II collagen. This finding suggests that type-M collagen may play an important role in the metabolism of articular cartilage.

Animals↗
PubMed1993

Altered Golgi apparatus in hydrostatically loaded articular cartilage chondrocytes.

OBJECTIVES: Articular cartilage proteoglycan content is controlled by joint loading. This study aimed to elucidate the role of hydrostatic pressure in this regulation. METHODS: Primary cultures of chondrocytes from bovine articular cartilage, grown on coverslips, were subjected to 5, 15, or 30 MPa hydrostatic pressure, applied continuously or cyclically at 0.125 or 0.05 Hz. The Golgi apparatus was visualised either by a fluorochrome coupled wheat germ agglutinin or by transmission electron microscopy. Proteoglycan synthesis was studied by the incorporation of sulphur-35 labelled sulphate. RESULTS: After 30 MPa continuous hydrostatic pressure, the Golgi apparatus was observed in a compact form with a concomitant decrease in proteoglycan synthesis. The normal stacked appearance of the Golgi apparatus was no more visible in the electron microscopy preparation of the pressurised chondrocytes. This effect was reversible and was also noticed after 15 MPa continuous load, though to a minor extent. Cyclic pressures (5-30 MPa) caused no apparent change in the Golgi apparatus. The shape of some cells changed to a more retracted form after 30 MPa continuous pressure. Nocodazole, which causes disassembly of the microtubules, blocked the compacting influence of pressurisation on the Golgi apparatus, and reduced proteoglycan synthesis to about half of the control level. CONCLUSIONS: The packing of the Golgi apparatus is dependent on microtubules and may contribute to the inhibition of proteoglycan synthesis observed in articular cartilage subjected to high hydrostatic pressure.

Animals↗
PubMed1988

Thrombospondin is present in articular cartilage and is synthesized by articular chondrocytes.

Thrombospondin, a multifunctional adhesive glycoprotein originally identified in platelets, was isolated and identified from an extract of ovine articular cartilage. Immunoreactive material from a cartilage extract comigrated on gel electrophoresis with purified human platelet thrombospondin. When articular chondrocytes were cultured in the presence of 35S-methionine, metabolically labeled thrombospondin was immunoprecipitated from the culture medium and cell layer extract. These results demonstrate that thrombospondin is present in articular cartilage and is synthesized by articular chondrocytes.

Animals↗
PubMed2006

Disassembly of the vimentin cytoskeleton disrupts articular cartilage chondrocyte homeostasis.

Articular cartilage functions in dissipating forces applied across joints. It comprises an extracellular matrix containing primarily collagens, proteoglycans and water to maintain its functional properties, and is interspersed with chondrocytes. The chondrocyte cytoskeleton comprises actin microfilaments, tubulin microtubules and vimentin intermediate filaments. Previous studies have determined the contribution of actin and tubulin in regulating the synthesis of the extracellular matrix components aggrecan and type II collagen. The contribution of vimentin to extracellular matrix biosynthesis in any cell type has not previously been addressed. Therefore the aim of this study was to assess the role of vimentin in cartilage chondrocyte metabolism. Vimentin intermediate filaments were disrupted in high-density monolayer articular chondrocyte cultures using acrylamide for 7 days. De novo protein and collagen synthesis were measured by adding [3H]-proline, and sulphated glycosaminoglycan (sGAG) synthesis measured by adding [35S]-sulphate to cultures. Vimentin disruption resulted in decreased collagen synthesis, whilst sGAG synthesis was unaffected. In addition, there was a significant reduction in type II collagen and aggrecan gene transcription suggesting that the effects observed occur at both the transcriptional and translational levels. A 3-day cold chase demonstrated a significant inhibition of collagen and sGAG degradation; the reduction in collagen degradation was corroborated by the observed reduction in both pro-MMP 2 expression and activation. We have demonstrated that an intact vimentin intermediate filament network contributes to the maintenance of the chondrocyte phenotype and thus an imbalance favouring filament disassembly can disturb the integrity of the articular cartilage, and may ultimately lead to the development of pathologies such as osteoarthritis.

Acrylamide↗
PubMed1977

Surface ultrastructure of rheumatoid articular cartilage.

Six rheumatoid articular cartilage specimens, which appeared grossly normal and were shown to be free of pannus when examined under the light microscope, were examined electron microscopically. For comparison, normal-appearing cartilage specimens from 2 patients with meniscus injury and 2 with degenerative joint disease (DJD) were also examined. In all cases the normal-appearing joint surface of rheumatoid cartilage was abnormal. Amorphous-appearing material was present to a depth varying between 6 and 25 micron. Some of this material had the appearance of fibrin deposited at the cartilage surface, but much appeared to represent breakdown products of the cartilage matrix, i.e. degraded collagen and proteoglycan. DJD cartilage did not show similar changes. The findings suggest that the surface of rheumatoid articular cartilage, even when grossly normal in appearance, is degraded by enzymes either present in the synovial fluid or released by polymorphonuclear cells in close contact with the cartilage surface.

Adult↗
PubMed2000

The deformation behavior and viscoelastic properties of chondrocytes in articular cartilage.

Chondrocytes in articular cartilage utilize mechanical signals in conjunction with other environmental factors to regulate their metabolic activity. However, the sequence of biomechanical and biochemical events involved in the process of mechanical signal transduction has not been fully deciphered. A fundamental step in determining the role of various factors in regulating chondrocyte activity is to characterize accurately the biophysical environment within the tissue under physiological conditions of mechanical loading. Microscopic imaging studies have revealed that chondrocytes as well as their nuclei undergo shape and volume changes in a coordinated manner with deformation of the tissue matrix. Through micromechanical experiments, it has been shown that the chondrocyte behaves as a viscoelastic solid material with a mechanical stiffness that is several orders of magnitude lower than that of the cartilage extracellular matrix. These properties seem to be due to the structure of the chondrocyte cytoskeleton, and in part, the viscoelastic properties of the cell nucleus. The mechanical properties of the pericellular matrix that immediately surrounds the chondrocyte significantly differ from those of the chondrocyte and the extracellular matrix, suggesting that the pericellular matrix plays an important role in defining the mechanical environment of the chondrocyte. These experimentally measured values for chondrocyte and cartilage mechanical properties have been used in combination with theoretical constitutive modeling of the chondrocyte within articular cartilage to predict the non-uniform and time-varying stress-strain and fluid flow environment of the cell. The ultimate goal of these studies has been to elucidate the sequence of biomechanical and biochemical events through which mechanical stress influences chondrocyte activity in both health and in disease.

Animals↗
PubMed2005

Regeneration of articular cartilage.

Loss of articular cartilage from the ends of bones forming diarthrodial joints can be the source of profound pain and disability, and eventually lead to complete degeneration of the joint, necessitating total joint replacement. Until a few years ago, there seemed little hope of treating such defects. Novel surgical procedures and cell therapies have recently been found, however, to stimulate the formation of reparative tissue resulting in the relief of pain and restoration of function, at least for a limited time period. Moreover, studies of the healing of chondral defects in animal models have revealed that there is some potential for regeneration of this connective tissue. The introduction of certain biomaterial scaffolds along with selected surgical procedures and cell therapies has been demonstrated in animal studies to facilitate the cartilage reparative process and now offers the promise of extending the longevity of clinical treatments of cartilage defects. Collectively these findings provide the basis for the rational development of approaches for the more complete regeneration of articular cartilage, and demonstrate that meaningful clinical outcomes can be achieved even if complete regeneration is not achieved.

Animals↗
PubMed2000

Use of recombinant human osteogenic protein-1 for the repair of subchondral defects in articular cartilage in goats.

The objective of this pilot study was to examine in vivo the potential of recombinant human osteogenic protein-1 (rhOP-1, also called bone morphogenetic protein-7, BMP-7) for treatment of subchondral lesions by induction of new hyaline cartilage formation. Subchondral left knee defects in 17 mature goats were treated with fresh coagulated blood mixed with (1) rhOP-1 combined with collagen (OP-1 device, 400 microgram/mL); (2) rhOP-1 alone (OP-1 peptide, 200 microgram/mL); (3) OP-1 device with small particles of autologous ear perichondrium; (4) OP-1 peptide with small particles of autologous ear perichondrium; or (5) autologous ear perichondrium alone (controls). rhOP-1 was combined with either collagen (OP-1 device) or not (OP-1 peptide). The defects were closed with a periosteal flap. The formation of cartilage tissue was studied by histologic and biochemical evaluation at 1, 2, and 4 months after implantation. One and 2 months after implantation there were no obvious differences between control and rhOP-1-treated defects. Four months after implantation, only one out of three controls (without rhOP-1) showed beginning signs of cartilage formation while all four rhOP-1-treated defects were completely or partly filled with cartilage. A significant linear relationship was found between rhOP-1 concentration and the total amount of aggrecan in the defects. These results suggest that implantation of rhOP-1 promotes cartilage formation in subchondral defects in goats at 4 months after implantation. Therefore, rhOP-1 could be a novel factor for regeneration of cartilage in articular cartilage defects.

Animals↗