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PubMed2001

Polymorphonuclear leukocyte adhesion to articular cartilage is inhibited by cartilage surface macromolecules.

The present studies deal with polymorphonuclear neutrophil (PMN) adhesion inhibitory properties of cartilage surface proteoglycans. Normal human PMN were used in adhesion experiments with bovine cartilage surfaces exposed to neutrophil elastase and reconstituted with fibronectin (Fn) or on plastic-bound Fn. An extract of cartilage surface small proteoglycans (SE) and purified fibromodulin (FM), decorin (DCN), biglycan (BGN), and aggrecan (AGN) on the surface of normal cartilage were used to test for inhibition of Fn-dependent cell adhesion. The PMN did not adhere to intact articular cartilage surfaces, whereas significant adhesion was measured using cartilage explants digested with elastase and reconstituted with Fn. Incubation of elastase-treated, Fn-reconstituted cartilage with 45 microg/ml SE inhibited PMN adhesion by 50.7 +/- 5.8% (P < 0.0001). Addition of 50 microg/ml purified FM to the reconstituted articular surfaces inhibited cell adhesion by 71.2 +/- 13.9% (P < 0.0001). Inhibition of PMN adhesion to plastic-bound Fn was seen with 1.7 microg/ml SE (20.4 +/- 8.0%). Maximal inhibition of 67.4 +/- 14.8% (P < 0.01) was obtained with 17.0 microg/ml SE. With FM, concentrations of 4.3 microg/ml resulted in 34.7 25.2 inhibition (P < 0.001), and maximal inhibition of 66.3 16.2% (P < 0.01) was obtained with 43.0 microg/ml. Similar results were obtained with purified bovine DCN and BGN. The main component of cartilage matrix, AGN, failed to inhibit cell adhesion significantly. The results indicate that macromolecules normally present on articular cartilage surfaces act as a barrier to PMN adhesion. Since cartilage surface proteins are susceptible to breakdown by proteases from synovial fluid inflammatory cells, we postulate that the degradation of this barrier may be responsible for increasing PMN adhesion and subsequent cartilage damage in inflammatory arthritis.

Aggrecans↗
PubMed2005

The effect of detachment of the articular cartilage from its calcified zone on the cartilage microstructure, assessed by 2H-spectroscopic double quantum filtered MRI.

Most studies on articular cartilage properties have been conducted after detachment of the cartilage from the bone. In the present work we investigated the effect of detachment on collagen fiber architecture. We used one-dimensional (2)H double quantum filtered MRI on cartilage bone plugs equilibrated in deuterated saline. The quadrupolar splittings observed in the different zones were related to the degree of order and the density of the collagen fibers. The method is non-destructive, allowing for measurements on the same plug without the need for fixation, dehydration, sectioning and decalcification. Detachment of the radial from the calcified zone resulted in swelling of the cartilage plug in physiological saline and a concomitant decrease in the quadrupolar splitting. The effect of mechanical pressure on the (2)H quadrupolar splittings for the detached cartilage and for the calcified zone-bone plugs were compared with those of the same zones in the intact cartilage-bone plug. The splitting in the radial zone of the detached cartilage collapsed at much smaller loads compared to the intact cartilage-bone plug. The effect of the load on the size of the cartilage was also greater for the detached plug. These results indicate that anchoring of the cartilage to the bone through the calcified zone plays an important role in retaining the order of the collagen fibers. The water (2)H quadrupolar splitting in intact and proteoglycan-depleted cartilage was the same, indicating that the proteoglycans do not contribute to the ordering of the collagen fibers.

Animals↗
PubMed2001

Bilaminar pattern of tibial condyle cartilage layer on the fat-suppressed 3D gradient echo images: artifact or structural and biochemical difference in composition of cartilage?

The purpose of this study was to examine if an unusual bilaminar pattern of lateral tibial condyle cartilage layer on the fat-suppressed three-dimensional (3D) spoiled gradient echo sequence is artifactual or correlates with structural and/or biochemical composition of cartilage. The laminar appearance of the lateral tibial condyle cartilage layer was studied on fat-suppressed 3D spoiled gradient echo MR images of the knee joint in 67 patients (mean age: 28y) performed at 1.0 Tesla. After i.v. administration of gadopentetate dimeglumine, diffusion of the contrast media into cartilage layer was qualitatively analysed over time on inversion recovery spin echo images of knee joints of five asymptomatic volunteers (mean age: 25y). In a patient with osteosarcoma and total knee replacement, MR examination of cartilage layer of lateral tibial plateau was compared with histologic specimens stained with Safranin-O, demonstrating proteoglycan distribution in cartilage. The retrospective analysis of 67 knee joints revealed a bilaminar appearance of lateral tibial condyle cartilage layer in the gradient echo images in the majority of cases (81%) with a statistically significant tendency to a trilaminar pattern in patients older than 20 years. With i.v. contrast administration, the contrast enhancement was only observed in the superficial zone of tibial cartilage layer. Histologic specimens in one patient demonstrated a good correlation between thickness of proteoglycan-free and proteoglycan-rich laminae of lateral tibial condyle on Safranin-O staining with hyperintense and hypointense zones, respectively, on corresponding fat-suppressed 3D spoiled gradient echo images (correlation coefficient of 0.87). Bilaminar pattern of tibial condyle cartilage layer on fat-suppressed 3D spoiled gradient echo images in younger subjects is not an artifact or an intrachondral lesion, but it may represent a regional difference in composition of extracellular cartilage matrix possibly produced by a highly-oriented collagen fiber structure associated with a high concentration of proteoglycans in the middle and deep portion of the cartilage layer.

Adolescent↗
PubMed2003

Templates of the cartilage layers of the patellofemoral joint and their use in the assessment of osteoarthritic cartilage damage.

OBJECTIVE: To develop a methodology for generating templates that represent the normal human patellofemoral joint (PFJ) topography and cartilage thickness, based on a statistical average of healthy joints. Also, to determine the cartilage thickness in the PFJs of patients with osteoarthritis (OA) and develop a methodology for comparing an individual patient's thickness maps to the normal templates in order to identify regions that are most likely to represent loss of cartilage thickness. DESIGN: The patella and femur surfaces of 14 non-arthritic human knee joints were quantified using either stereophotogrammetry or magnetic resonance imaging. The surfaces were aligned, scaled, and averaged to create articular topography templates. Cartilage thicknesses were measured across the surfaces and averaged to create maps of normal cartilage thickness distribution. In vivo thickness maps of articular layers from 33 joints with OA were also generated, and difference maps were created depicting discrepancies between the patients' cartilage thickness maps and the normative template. RESULTS: In the normative template, the surface-wide mean+/-SD (maximum) of the cartilage thickness was 2.2+/-0.4mm (3.7mm) and 3.3+/-0.6mm (4.6mm) for the femur and patella, respectively. It was demonstrated that difference maps could be used to identify regions of thinner-than-normal cartilage in patients with OA. Patients were shown to have statistically greater regions of thin cartilage over their articular layers than the normal joints. On average, patients showed deficits in cartilage thickness in the lateral facet of the patella, in the anterior medial and lateral condyles, and in the lateral trochlea of the femur. CONCLUSIONS: This technique can be useful for in vivo clinical evaluation of cartilage thinning in the osteoarthritic patellofemoral joint.

Adult↗
PubMed2003

Experimental model for cartilage tissue engineering to regenerate the zonal organization of articular cartilage.

OBJECTIVE: Regeneration of the zonal organization of articular cartilage may be an important advancement for cartilage tissue engineering. The first goal of this study was to validate our surgical technique as a method to selectively isolate chondrocytes from different zones of bovine articular cartilage. The second goal was to confirm that chondrocytes from different zones would have different proliferative and metabolic activities in two-dimensional (2-D) and 3-D cultures. Finally, to regenerate the zonal organization, we sought to make multi-layered constructs by encapsulating chondrocytes from different zones of articular cartilage. DESIGN: Cartilage slices were removed from three (upper, middle, and lower) zones of articular cartilage of young bovine legs. Histology and biochemical composition of the cartilage slices were analyzed to confirm that they had been obtained from the proper zone. Growth kinetics and gene expression in monolayer culture and matrix formation in photopolymerizing hydrogels were evaluated. Multi-layered photopolymerizing hydrogels were constructed with chondrocytes from each zone of native cartilage encapsulated. Cell viability and maintenance of the cells in the respective layer were evaluated using the Live/Dead Viability kit and cell tracking protocols, respectively. After 3 weeks, the multi-layered constructs were harvested for histologic examination including immunohistochemistry for type II collagen. RESULTS: Analysis of histology and biochemical composition confirmed that the cartilage slices had been obtained from the specific zone. Chondrocytes from different zones differed in growth kinetics and gene expression in monolayer and in matrix synthesis in 3-D culture. Cells encapsulated in each of the three layers of the hydrogel remained viable and remained in the respective layer in which they were encapsulated. After 3-week culture, each zone of multi-layered constructs had similar histologic findings to that of native articular cartilage. CONCLUSION: We present this as an experimental model to regenerate zonal organization of articular cartilage by encapsulating chondrocytes from different layers in multi-layered photopolymerizing gels.

Animals↗
PubMed1992

Pathogenic importance of fibronectin in the superficial region of articular cartilage as a local factor for the induction of pannus extension on rheumatoid articular cartilage.

To identify the local factors in cartilage that are responsible for the induction of pannus invasion, a 14 day organ culture study in which rheumatoid synovium was grown in contact with cartilage pieces was carried out. Rheumatoid synovium preferentially extended over hyaluronidase treated cartilage pieces, but detached from untreated pieces. Rheumatoid synovium extended over hyaluronidase treated cartilage surfaces containing fibronectin more extensively than over surfaces treated with hyaluronidase only. Extension over hyaluronidase treated cartilage surfaces containing immune complexes was small. The adherence of synovial cells to hyaluronidase treated cartilage slices in vitro was specifically inhibited by the synthetic peptide, Gly-Arg-Gly-Asp-Ser-Pro, which is the adhesive portion of the fibronectin molecule. Furthermore, synovial fibroblast-like cellular extension, morphologically similar to rheumatoid pannus, was observed in the organ culture experiments in which rheumatoid synovium grew over hyaluronidase treated cartilage surfaces containing fibronectin. Synovial tissue extension over fibronectin coated surfaces was inhibited when hyaluronic acid and chondroitin-4-sulphate, major components of cartilage proteoglycans, were present on the cartilage surface. These findings suggest that fibronectin present in the superficial region of cartilage potentiates rheumatoid synovial extension and proteoglycans and immune complexes inhibit rheumatoid synovial extension. It is likely that fibronectin deposited on the eroded surface of articular cartilage induces pannus formation in rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1989

Immunohistochemical detection and immunochemical analysis of type II collagen degradation in human normal, rheumatoid, and osteoarthritic articular cartilages and in explants of bovine articular cartilage cultured with interleukin 1.

Articular cartilage destruction and loss of function in arthritic diseases involves proteolytic degradation of the connective tissue matrix. We have investigated the degradation of cartilage collagen by developing immunochemical methods that permit the identification and analysis of type II collagen degradation in situ. Previously, a technique to specifically identify type II collagen degradation in situ in articular cartilage did not exist. These methods utilize a polyclonal antiserum (R181) that specifically reacts with unwound alpha-chains and CNBr-derived peptides, alpha 1(II)CB11 and alpha 1(II)CB8, of human and bovine type II collagens. The experimental approach is based on the fact that when fibrillar collagens are cleaved the helical collagen molecule unwinds, exposing hidden epitopes. Here we demonstrate the use of R181 in studying type II collagen degradation in bovine articular cartilage that has been cultured with or without IL-1 and in human normal, rheumatoid, and osteoarthritic articular cartilages. Compared to cartilages either freshly isolated or cultured without IL-1, bovine cartilage cultured with IL-1 for 3-5 d showed an increase in both pericellular and intercellular immunohistochemical staining. Extracts of these cartilages contained type II collagen alpha chains that were increased in amount after culture with IL-1 for 11 d. In addition, culture with IL-1 resulted in the appearance of alpha chain fragments of lower molecular weight. All human arthritic tissues examined showed areas of pronounced pericellular and territorial staining for collagen degradation as compared with non-diseased tissues, indicating that chondrocytes are responsible in part for this degradation as compared with non-diseased tissues. In most cases rheumatoid cartilage was stained most intensely at the articular surface and in the deep and mid-zones, whereas osteoarthritic cartilage usually stained more in the superficial and mid-zones, but less intensely. Distinct patterns of sites of collagen degradation reflect differences in collagen destruction in these diseases, suggesting possible different sources of chondrocyte activation. These experiments demonstrate the application of immunological methods to detect collagen degradation and demonstrate an increase of collagen degradation in human arthritides and in IL-1-treated viable bovine cartilage.

Animals↗
PubMed1994

A "coupled" subchondral bone-articular cartilage tissue culture system for the study of cartilage proteoglycan metabolism.

Current evidence suggests that interactions between the subchondral bone and the articular cartilage of mammalian diarthrodial joints may occur through the action of bone-associated peptide factors. However, there is no suitable organ culture model for studying these interactions. This study defines a long-term tissue culture system where the articular cartilage is coupled to the adjacent subchondral bone obtained from the proximal ends of bovine metacarpals. Autoradiography done over 3 mo., by utilizing [35S]SO4 incorporation into cartilage proteoglycan (PG) and a procedure for cutting non-decalcified bone, demonstrated similar numbers of silver grains over chondrocytes in all cartilage zones, including the bone-cartilage interface. Newly synthesized PG (NSPG) from the cartilage of the "coupled" system over a 3-wk period was primarily of large hydrodynamic size (Kav of 0.34). Comparable bovine articular and nasal cartilage slice systems, incubated for short periods of time, yielded similar and somewhat larger NSPG, respectively. Labeled chondroitin sulphate PG accumulating in the medium of primary chondrocyte monolayer cultures, derived from the cartilage of the coupled system at 0, 1, 2, and 3 wk, revealed two polydisperse subpopulations (Kav of 0.30 to 0.38 and 0.51 to 0.68). We conclude that this coupled bone-cartilage system is viable for prolonged periods, is suitable for studies on the metabolism of articular cartilage PGs, and seems to have some advantages over the cultured articular cartilage slice system.

Animals↗
PubMedDate not supplied

The stimulation of mononuclear cells from patients with rheumatoid arthritis to degrade articular cartilage is not modulated by cartilage itself.

OBJECTIVE: To study the modulation of mononuclear cell (MNC) activity in patients with rheumatoid arthritis (RA) by constituents released from human articular cartilage, which may be present in vivo during early events of the disease, when articular cartilage is not only mildly damaged. METHODS: In an attempt to stimulate RA MNC, cells were co-cultured with healthy or mildly damaged articular cartilage tissue. In addition, because of the reported cross-reactivity between cartilage constituents and mycobacterial heat-shock protein (hsp60), RA MNC sensitized with hsp60 were also co-cultured with cartilage tissue. Activation of the RA MNC was assessed by analysing the production of catabolic factors involved in joint damage. For this purpose culture supernatants of the treated RA MNC, comprising the catabolic factors, were added to freshly isolated articular cartilage explants. As a read out for catabolic activity, proteoglycan (PG) turnover by the explants was determined. RESULTS: Spontaneous activity of untreated RA MNC caused inhibition of PG synthesis and increased PG release upon addition of their culture supernatants to the cartilage explants. This MNC activity was not enhanced by the constituents released from healthy or mildly damaged cartilage tissue, whereas sensitization of RA MNC with hsp60 resulted in a 40% enhanced inhibition of PG synthesis. However, even under these pre-activated conditions no reactivity towards the cartilage constituents could be observed. CONCLUSION: Cartilage constituents released from mildly damaged cartilage tissue, as may be present during the early events of RA. do not modulate the catabolic activity of RA MNC.

Adult↗
PubMed2004

Ultrasonography and articular cartilage defects in the knee: an in vitro evaluation of the accuracy of cartilage thickness and defect size assessment.

The purpose of this cadaver study was to test the accuracy of ultrasonography in measuring cartilage thickness, and the extent and depth of induced cartilage defects on the medial and lateral femoral condyles of the knee in a clinically relevant setting. With the knees maximally flexed, cartilage thickness was measured at 24 marked sites in four knees with a 10 MHz probe. The areas of measurement were then excised and the thickness measured with a calliper gauge. In another seven cadaver knees, 21 cartilage defects were produced. The defect diameter varied from 4 to 8 mm. The depths of the defects were either a partial cartilage defect (grade 2), a defect to intact subchondral bone (grade 3), or a defect involving subchondral bone (grade 4) (classification by ICRS). The limits of agreement between ultrasonography and calliper gauge measurement for cartilage thickness were chi(diff)+/-2SD(diff)=0.0+/-0.4 mm. For cartilage defect diameter, the limits of agreement between ultrasonography and the slide ruler measurement were chi(diff)+/-2SD(diff)=-0.2+/-1.0 mm. For the depths of the lesions there was a 100% agreement between radiologist and actual lesion depth for the classification into International Cartilage Repair Society (ICRS) grades 2, 3, and 4. Our conclusion is that ultrasonography is capable of measuring accurately both cartilage thickness and the extent and depth of induced cartilage defects in a cadaver model.

Aged↗
PubMed2003

[Value of autologous transplantation of osteo-chondral paste in reconstruction of experimental cartilage defects. Part II. Microscopic analysis of integration with surrounding cartilage, structural integrity and subchondral bone reconstruction in repair tissue].

INTRODUCTION: A limited ability of the cartilage to heal after trauma was the reason to start research on new methods concerning better cartilage reconstruction. The aim of the study was evaluation of repair tissue integration with surrounding cartilage, its structural integrity and subchondral bone reconstruction after osteo-chondral paste transplantation. MATERIAL AND METHODS: Full thickness defect (IV degree--ICRS scale) on distal rabbit femur joint surface was made. Three groups were specified: A--defect with paste graft (cartilage and contiguous bone collected from joint surface, crushed into homogenous paste; B--defect with the paste graft covered with periosteum; C--defect left unfilled. The follow-up periods were established at 4, 8, 12 weeks. Repair tissue was evaluated microscopically according to modified O'Driscoll scale. RESULTS: Newly formed tissue was well integrated with surrounding cartilage in group A (paste graft). That trade of repair tissue in group A was much better than in other groups, especially in late observations. Structural integrity of tissue filling the defect was similar to integrity of normal cartilage in groups A and C, but tissue formed in group C didn't represent a hyaline-like cartilage character. In all the examined groups reconstruction of subchondral bone exhibited similar rate. 12 weeks from the procedure, around 80% of subchondral bone was rebuilt. The obtained results indicate, that osteo-chondral paste autologous transplantation in cartilage defects treatment effects with forming well integrated (structurally and with surrounding cartilage) cartilage tissue, of almost complete subchondral bone rebuilding.

Animals↗
PubMed1983

Isozymes of glycogen phosphorylase in human cartilage and cartilage tumors.

Isozyme patterns of glycogen phosphorylase in normal fetal and adult human cartilage and benign and malignant cartilage tumors were investigated by means of polyacrylamide gel disc electrophoresis. In both normal cartilage and cartilage tumors four distinct bands were observable: these were of the liver, liver-like and fetal types and of a hybrid type between the muscle and fetal types judging by their mobilities in the small-pore gels containing 0.01% and 0.1% glycogen. The isozyme pattern of benign cartilage tumors was almost identical with that of normal cartilage. In normal fetal and adult cartilage and benign cartilage tumors, the liver and liver-like types were predominant, whereas in malignant cartilage tumors they were minor and the fetal type was predominant. These results indicate fetal deviation of phosphorylase isozymes in malignant transformation of cartilage cells.

Adult↗
PubMed1998

Cartilage-derived morphogenetic proteins and cartilage morphogenesis.

Cartilage morphogenesis is a prerequisite for skeletal development and maintenance. The morphogenesis of cartilage determines the shape of bones, and joints including articular cartilage, ligaments, and tendon. This article reviews the recent advances in cartilage-derived morphogenetic proteins (CDMPs) and related bone morphogenetic proteins (BMPs). Cartilage-derived morphogenetic proteins (CDMPs) are related to BMPs and are critical for cartilage and joint morphogenesis. Cartilage morphogenesis is a multistep cascade that includes factors for initiation, promotion, and maintenance of cartilage phenotype. The extracellular matrix of cartilage consists of a constellation of macromolecules such as collagens, proteoglycans, and glycoproteins. Morphogens bind to extracellular matrix components and assemble a morphogenetic scaffold. Recent advances in CDMPs may aid in articular cartilage repair and regeneration.

Animals↗
PubMed2002

Bone morphogenetic proteins promote cartilage differentiation and protect engineered artificial cartilage from fibroblast invasion and destruction.

OBJECTIVE: An important role in joint and cartilage homeostasis in adults has been demonstrated recently for morphogenetic factors of the transforming growth factor beta family. Therefore, this study was undertaken to investigate the potential of bone morphogenetic proteins (BMPs) in chondrocyte differentiation using current technologies of tissue engineering. METHODS: Complementary DNAs of recombinant human BMPs 2, 4, 5, 6, and 7 were transfected into primary bovine articular chondrocytes. Transgenic chondrocytes were assembled 3-dimensionally in alginate or in bioresorbable co-polymer fleeces of vicryl and polydioxanon embedded in low-melting-point agarose. Redifferentiation and formation of cartilage tissue in vitro or after subcutaneous transplantation into nude mice were assayed by semiquantitative reverse transcriptase-polymerase chain reaction, histology, and in situ hybridization, and findings were compared with those in unmodified or control-transfected primary chondrocytes. RESULTS: Compared with other BMPs and control vector, BMP-7 induced a decrease in type I collagen expression in artificial cartilage, while transcription of the cartilage-specific type II collagen remained stable. In transplantation experiments, BMP-7 transgenic cartilage revealed the greatest amount of matrix synthesis, and BMP-7 was the only morphogen to suppress the infiltrative response of mouse fibroblastic cells into engineered cartilage, thereby preventing transplant destruction. CONCLUSION: Cartilage differentiation and matrix maturation are promoted by BMPs in cartilage engineering. The inhibitory effect of BMP-7 on a nonspecific infiltrative response in immunocompromised nude mice further suggests that individual morphogens not only may contribute to cartilage maturation, but also may protect it from nonspecific inflammation and invasive destruction. These properties advance BMPs as promising tools for engineering of cartilaginous joint bioprostheses and as candidate biologic agents or genes for cartilage stabilization in arthritis.

Animals↗
PubMed1983

Ultrastructure of cartilage from young adult sea lamprey, Petromyzon marinus L: a new type of vertebrate cartilage.

Ultrastructural observations of cartilage from adult sea lamprey, Petromyzon marinus, reveal a highly cellular cartilage with an unusual extracellular matrix. The avascular cartilage is surrounded by a vascular perichondrium, which consists of dense connective tissue containing fibroblasts, collagen fibrils, and microfibrils. The cells (chondrocytes) vary in morphology in different parts of the cartilage in a way that may reflect their state of activity. Chondrocytes within the peripheral cartilage contain tubulo-vesicular structures along the cell surface, an extensive lamellar rough endoplasmic reticulum, and a well-developed Golgi complex with associated vesicles and vacuoles. The presence of material within the Golgi elements that resembles components of the extracellular matrix suggests the involvement of the peripheral chondrocytes in the synthesis and secretion of the matrix components. Chondrocytes within the central cartilage are hypertrophied and contain a pale cytoplasm with a reduced number of organelles that are widely spaced throughout the cell. The appearance of the organelles within these cells suggests that they are not as actively involved in the production of the matrix as those of the peripheral cartilage. The extracellular matrix consists of a dense network of randomly arranged, branched, noncollagenous matrix fibrils 15-40 nm in diameter and varying amounts of electron-dense matrix granules. Due to the unique nature of its extracellular matrix, the cartilage of the lamprey cannot be likened to any of the known vertebrate cartilages and, therefore, must be considered a new type of vertebrate cartilage.

Animals↗
PubMed2002

Specific enzymatic treatment of bovine and human articular cartilage: implications for integrative cartilage repair.

OBJECTIVE: Chondrocyte death in articular cartilage wound edges and the subsequent lack of matrix-producing cells in the interface area are considered to be a major cause of impaired cartilage wound healing and poor integrative cartilage repair. This study was undertaken to investigate whether enzymatic matrix digestion can be used to stimulate integrative cartilage repair via a mechanism of local increase in the amount of vital chondrocytes in cartilage wound edges. METHODS: Full-thickness bovine articular cartilage samples were cultured in vitro for 14 days in standard medium. Samples were either left untreated or treated for 48 hours with 0.3% hyaluronidase or 30 units/ml highly purified collagenase VII. Nuclear and cytoplasmic changes were analyzed to determine cell viability, and the number of vital chondrocytes in wound edges was determined. Subsequently, we investigated whether increased chondrocyte density in the lesion edges resulted in better wound healing. Finally, full-thickness human tibial plateau cartilage explants were tested with similar enzyme treatment protocols to determine the clinical value of our results. RESULTS: In bovine explants a rapid onset of chondrocyte death was observed in wound edges in all treatment groups. This led to low chondrocyte density in a band of 0-150 microm from the lesion edges in untreated and hyaluronidase-treated explants. Treatment with 30 units/ml collagenase resulted in a significant increase in chondrocyte density in this area. The integration experiments demonstrated improved integration of the lesion edges after treatment with collagenase. In human articular cartilage an increase in chondrocyte density at the lesion edges could also be achieved, but only when proteoglycans were depleted from the wound edges prior to collagenase treatment. CONCLUSION: Treatment with highly purified collagenase improves integrative cartilage repair, possibly by increasing the cell density at cartilage wound edges.

Adult↗
PubMed2005

Cartilage glycosaminoglycan loss in the acute phase after an anterior cruciate ligament injury: delayed gadolinium-enhanced magnetic resonance imaging of cartilage and synovial fluid analysis.

OBJECTIVE: To examine the glycosaminoglycan (GAG) content in cartilage and that in synovial fluid and determine whether they are associated, in patients with an acute anterior cruciate ligament (ACL) injury. METHODS: Twenty-four patients (14 of whom were male) with a mean age of 27 years (range 17-40 years) were assessed with delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage an average of 3 weeks after an ACL rupture and compared with 24 healthy volunteers. Two hours after an intravenous injection of Gd-DTPA(2-) (0.3 mmoles/kg body weight), quantitative measurements of the T1 relaxation time (T1(Gd) [T1 relaxation time in the presence of Gd-DTPA]) were made in lateral and medial femoral weight-bearing cartilage. In the patients, synovial fluid was aspirated immediately before the MRI, and GAG was analyzed using dye precipitation with Alcian blue. RESULTS: Fifteen of the 24 patients had an isolated bone bruise in the lateral femoral condyle, where the cartilage T1(Gd) was shorter than that in the controls (mean +/- SD 385 +/- 83 msec and 445 +/- 41 msec, respectively; P = 0.004), consistent with decreased GAG content. However, the T1(Gd) was also decreased in the medial femoral cartilage, where bone bruises were rare (376 +/- 76 msec in patients versus 428 +/- 38 msec in controls; P = 0.006). The mean +/- SD synovial fluid GAG concentration in patients was 157 +/- 86 mug/ml and showed a positive correlation with the T1(Gd) (r = 0.49, P = 0.02). CONCLUSION: This study indicates that an ACL injury causes posttraumatic edema of the lateral femoral cartilage but initializes a generalized biochemical change within the knee that leads to GAG loss from both lateral and medial femoral cartilage. In cartilage with a high GAG content (long T1(Gd)), more GAG is released into the synovial fluid, suggesting that cartilage quality is a factor to consider when interpreting cartilage biomarkers of metabolism.

Adolescent↗
PubMed2004

Investigations into growth and differentiation in the cartilage of the condylar process in the domestic pig. A quantitative study of endochondral cartilage growth and cell distribution.

AIM: The aim of this study was to examine the extent to which the ratio of the endochondral growth components cell volume increase to matrix production was subject to age-dependent and animal-specific changes per cell in the condylar cartilage of the domestic pig. In addition, it was to be investigated whether the cell distribution in the condylar cartilage and thus the tissue differentiation changes as one aspect of the aging process and whether the differentiation differs from that of primary hyaline cartilage. MATERIAL AND METHODS: The tissue specimens available were hematoxylin/eosin-stained section series from the cartilage of the condylar process of six domestic pigs (0-24 months) of the genus Suis scrofa. Using a special squared measuring grid in the optical path of a microscope, the following histomorphometric primary parameters were ascertained in the cartilage zones under investigation: the average section area of the cartilage cells and the number of cut cells per unit area. From these figures, the cell volume and the extracellular matrix volume per cell were calculated using the stereological calculation algorithm for ellipsoids of revolution in accordance with Weibel and Gomez. Quantitative analysis of the cell distribution pattern was based on two methods used in stochastic geometry: calculation of the dispersion index DI, and performance of the chi(2) adaptation test. RESULTS: It was shown that, in this species of experimental animal, the relative proportion of cell volume increase in the complete process of endochondral growth is predominant until the juvenile stage at 11 months. In late puberty, volume gain as a result of matrix synthesis then exceeds cell volume increase. Comparisons with other stereological growth studies show that the investigated ratio in the condylar cartilage of the domestic pig has a similar aging behavior to that in the rat. By contrast, the matrix synthesis is predominant in the monkey. The cell clustering typical of mature hyaline cartilage in other joints was not observed at any stage in the development of the condylar cartilage. This suggests that the differentiation process is adapted in a special way to the stress-strain relationship in the temporomandibular joint. CONCLUSION: The methods used successfully in the present study for measuring and evaluating uninfluenced cartilage growth in the condylar process of the domestic pig is suitable for more extensive basic studies into the influence of orthodontic treatment on joint development.

Aging↗