Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CARTILAGE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,261 records · Page 70Linked to original sources
PubMed2005

MR imaging of articular cartilage at 1.5T and 3.0T: comparison of SPGR and SSFP sequences.

OBJECTIVE: To compare articular cartilage signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and thickness measurements on a 1.5 T and a 3.0 T magnetic resonance (MR) scanner using three-dimensional spoiled gradient recalled echo (3D-SPGR) and two 3D steady-state free precession (SSFP) sequences. METHODS: Both knees of five volunteers were scanned at 1.5 T and at 3.0 T using a transmit-receive quadrature extremity coil. Each examination consisted of a sagittal 3D-SPGR sequence, a sagittal fat suppressed 3D-SSFP (FS-SSFP) sequence, and a sagittal Dixon 3D-SSFP sequence. For quantitative analysis, we compared cartilage SNR and CNR efficiencies, as well as average cartilage thickness measurements. RESULTS: For 3D-SPGR, cartilage SNR efficiencies at 3.0 T increased compared to those at 1.5 T by a factor of 1.83 (range: 1.40-2.09). In comparison to 3D-SPGR, the SNR efficiency of FS-SSFP increased by a factor of 2.13 (range: 1.81-2.39) and for Dixon SSFP by a factor of 2.39 (range: 1.95-2.99). For 3D-SPGR, CNR efficiencies between cartilage and its surrounding tissue increased compared to those at 1.5 T by a factor of 2.12 (range: 1.75-2.47), for FS-SSFP by a factor 2.11 (range: 1.58-2.80) and for Dixon SSFP by a factor 2.39 (range 2.09-2.83). Average cartilage thicknesses of load bearing regions were not different at both field strengths or between sequences (P>0.05). Mean average cartilage thickness measured in all knees was 2.28 mm. CONCLUSION: Articular cartilage imaging of the knee on a 3.0 T MR scanner shows increased SNR and CNR efficiencies compared to a 1.5 T scanner, where SSFP-based techniques show the highest increase in SNR and CNR efficiency. There was no difference between average cartilage thickness measurements performed at the 1.5 T and 3.0 T scanners or between the three different sequences.

Adult↗
PubMed2005

Promotion of the intrinsic damage-repair response in articular cartilage by fibroblastic growth factor-2.

OBJECTIVE: To identify the effect of fibroblastic growth factor-2 (FGF-2) on the intrinsic damage-repair response in articular cartilage in vitro. METHODS: Articular equine cartilage explants, without subchondral bone, had a single impact load of 500 g applied from a height of 2.5 cm. Explants were then cultured in 0, 12, 25, 50 or 100 ng/ml FGF-2 for up to 28 days. Unimpacted discs served as controls for each time-point. Histological and immunohistochemical techniques were used to quantify and characterise the response of putative chondrocyte progenitor cells (CPC) to damage and FGF-2 treatment. RESULTS: FGF-2 significantly accelerated the appearance and increased the numbers of de novo repair cells identified histologically at the cartilage surface. The response was affected by the dose of FGF-2. The repair cells were shown to be chondrocytes by their expression of collagen types II, IX/XI, but not of type I collagen. In addition, these cells, and those underlying the articular surface, were shown to be immunopositive for Notch-1 and PCNA, markers for proliferating cartilage progenitor cells. CONCLUSIONS: The results of this study indicate that, following single impact load, CPC can be stimulated in mature articular cartilage in vitro. These CPC and the cells arising from them appear to represent the cartilage's response to damage. The timing of the appearance of CPC and their overall numbers can be significantly increased by FGF-2, providing further evidence for an important role for FGF-2 in modulating cartilage repair. These results indicate that further study into the mechanisms of repair in mature cartilage using this in vitro model are vital in understanding the repair capacity of mature cartilage.

Animals↗
PubMed2005

Fibroblast growth factor-18 stimulates chondrogenesis and cartilage repair in a rat model of injury-induced osteoarthritis.

OBJECTIVE: Osteoarthritis (OA) is the most common form of arthritis and a primary cause of disability, however, there are no treatments that can slow disease progression or repair damaged joint cartilage. Fibroblast growth factor-18 (FGF18) has been reported to have significant anabolic effects on cartilage. We therefore examined its effects on repair of cartilage damage in a rat meniscal tear model of OA. DESIGN: Surgical damage to the meniscus in rats leads to joint instability and significant damage to the articular cartilage at 3 weeks post-surgery. At this time, animals received bi-weekly intra-articular injections of FGF18 for 3 weeks, and the knee joints were then harvested for histologic examination. RESULTS: FGF18-induced dose-dependent increases in cartilage thickness of the tibial plateau, due to new cartilage formation at the articular surface and the joint periphery. The generation of new cartilage resulted in significant reductions in cartilage degeneration scores. The highest dose of FGF18 also induced an increase in chondrophyte size and increased remodeling of the subchondral bone. CONCLUSIONS: The results of this study demonstrate that FGF18 can stimulate repair of damaged cartilage in a setting of rapidly progressive OA in rats.

Animals↗
PubMed2005

Variation of cell and matrix morphologies in articular cartilage among locations in the adult human knee.

OBJECTIVE: Understanding of articular cartilage physiology, remodelling mechanisms, and evaluation of tissue engineering repair methods requires reference information regarding normal structural organization. Our goals were to examine the variation of cartilage cell and matrix morphology in different topographical areas of the adult human knee joint. METHODS: Osteochondral explants were acquired from seven distinct anatomical locations of the knee joints of deceased persons aged 20-40 years and prepared for analysis of cell, matrix and tissue morphology using confocal microscopy and unbiased stereological methods. Differences between locations were identified by statistical analysis. RESULTS: Medial femoral condyle cartilage had relatively high cell surface area per unit tissue volume in the superficial zone. In the transitional zone, meniscus-covered lateral tibia cartilage showed elevated chondrocyte densities compared to the rest of the knee while lateral femoral condyle cartilage exhibited particularly large chondrocytes. Statistical analyses indicated highly uniform morphology throughout the radial zone (lower 80% of cartilage thickness) in the knee, and strong similarities in cell and matrix morphologies among cartilage from the femoral condyles and also in the mediocentral tibial plateau. Throughout the adult human knee, the mean matrix volume per chondron was remarkably constant at approximately 224,000 microm(3), corresponding to approximately 4.6 x 10(6) chondrons per cm(3). CONCLUSIONS: The uniformity of matrix volume per chondron throughout the adult human knee suggests that cell-scale biophysical and metabolic constraints may place limitations on cartilage thickness, mechanical properties, and remodelling mechanisms. Data may also aid the evaluation of cartilage tissue engineering treatments in a site-specific manner. Results indicate that joint locations which perform similar biomechanical functions have similar cell and matrix morphologies; findings may therefore also provide clues to understanding conditions under which focal lesions leading to osteoarthritis may occur.

Adult↗
PubMed2005

Altered cartilage mechanics and histology in knee osteoarthritis: relation to clinical assessment (ICRS Grade).

OBJECTIVE: Substantial changes in articular cartilage composition and mechanical properties occur during the development of osteoarthritis (OA). While softening in the initial stage is reported and sometimes used as an indicator of early OA, there is a lack of data relating the macroscopic appearance of cartilage to its mechanical and histological properties in all stages of degeneration. Knowledge about the mechanical quality of the tissue is important for diagnostic reasons and the understanding of the development of OA. DESIGN: The cartilage areas of 21 osteoarthritic human cadaver tibia plateaus were classified using the International Cartilage Repair Society (ICRS) system. A material testing device determined the Young's modulus of the cartilage by unconfined compression. Histological analysis used haematoxylin and eosin staining and Safranin-O staining for the evaluation of the Mankin score. RESULTS: A correlation between increasing ICRS Grade and stiffness reduction was found (R2=0.69). Stiffness values were for ICRS Grades 1, 2 and 3: E1=0.50+/-0.14 MPa, E2=0.37+/-0.13 MPa and E3=0.28+/-0.12 MPa, respectively. The histological evaluation confirmed the ICRS classification (R2=0.74). A moderate correlation between Mankin score and cartilage stiffness was observed (R2=0.47). CONCLUSIONS: The results indicate a relation between structural, mechanical and histological changes in all stages of the degeneration. With increasing ICRS Grade the cartilage stiffness, which is primarily influenced by the integrity of the extracellular matrix, decreases. Therefore, methods of stiffness determination such as indentation may be used to characterize cartilage in all stages of OA. However, the data suggest that differentiating between healthy cartilage and ICRS Grade 1 may be difficult using mechanical testing alone.

Aged↗
PubMed2005

Cyclical articular joint loading leads to cartilage thinning and osteopontin production in a novel in vivo rabbit model of repetitive finger flexion.

OBJECTIVE: An in vivo rabbit model of repetitive joint flexion and loading was used to characterize the morphological effects of cyclical loading on articular cartilage. DESIGN: The forepaw digits of eight anesthetized New Zealand White adult female rabbits were repetitively flexed at 1 Hz with a mean peak digit load of 0.42 N for 2 h per day for 60 cumulative hours. Metacarpophalangeal joints were collected from loaded and contra-lateral control limbs, fixed, decalcified, embedded, and thin-sectioned. Serial sections were stained for histology or for immunohistochemistry. Morphometric data including the mean thicknesses of the uncalcified cartilage and of the calcified cartilage were collected from digital photomicrographs of safranin O-stained sections. The number of cells stained with anti-osteopontin antibody was counted. RESULTS: We observed a decrease in uncalcified cartilage mean thickness with no significant change in calcified cartilage thickness. We also observed a significant increase in the number of cells positive for osteopontin (OPN) in the uncalcified cartilage. These changes occurred without overt cartilage surface degeneration. CONCLUSIONS: Cyclical loading leads to changes at the tissue and cellular levels in articular cartilage. These changes are suggestive of tidemark advancement and may indicate a reactivation of cartilage mineralization steps analogous to endochondral ossification. This novel in vivo rabbit model of repetitive flexion and loading can be used to investigate the effects of cyclical loading on articular joints.

Animals↗
PubMed2005

Opposing cartilages in the patellofemoral joint adapt differently to long-term cruciate deficiency: chondrocyte deformation and reorientation with compression.

OBJECTIVE: The purposes of this study were to quantify patellofemoral histology in the feline knee 67 months post-anterior cruciate ligament transection (ACL-T) and to apply an in situ static load of physiological magnitude to the articular cartilage and evaluate the resulting cartilage and chondrocyte deformation. DESIGN: Six cats were sacrificed 67+/-6 months post-unilateral ACL-T. Static compression was applied to the cartilage surfaces of the patellofemoral joint using a cylindrical metal indentor. After fixation, full thickness osteochondral blocks were harvested and sections cut from not-indented and indented areas. Chondrocyte shape, orientation and volumetric fraction as well as cartilage thickness were evaluated. RESULTS: Experimental and contralateral patellae were histologically different compared to normal with thickened cartilage, rounded superficial chondrocytes, and uneven proteoglycan staining throughout. In contrast, no differences were apparent in 10 of the 12 femoral groove samples. The structural reorganisation of the experimental patellae cartilage that occurred with load was also different compared to normal. Specifically, the indentation shape was deeper and had steeper sides and the realignment of deep zone cells at angles of 45 degrees and 135 degrees observed in normal cartilage was no longer apparent in the experimental tissue. CONCLUSIONS: Two directly articulating cartilage surfaces of the feline patellofemoral joint have completely contrasting responses to long-term ACL-T. We speculate that this could be a result of the different nature of the loads experienced by the two surfaces (intermittent vs constant) and/or the differences in the histology and material properties of the two tissues in their normal state, and/or an inherent difference in the biological response capabilities of the articular cartilages.

Adaptation, Physiological↗
PubMed2005

A predominantly articular cartilage-associated gene, SCRG1, is induced by glucocorticoid and stimulates chondrogenesis in vitro.

OBJECTIVE: Cartilage tissue engineering using multipotential human mesenchymal stem cells (hMSCs) is a promising approach to develop treatment for degenerative joint diseases. A key requirement is that the engineered tissues maintain their hyaline articular cartilage phenotype and not proceed towards hypertrophy. It is noteworthy that osteoarthritic articular cartilage frequently contains limited regions of reparative cartilage, suggesting the presence of bioactive factors with regenerative activity. Based on this idea, we recently performed cDNA microarray analysis to identify genes that are strongly expressed only in articular cartilage and encode secreted gene products. One of the genes that met our criteria was SCRG1. This study aims to analyze SCRG1 function in cartilage development using an in vitro mesenchymal chondrogenesis system. METHODS: Full-length SCRG1 cDNA was subcloned into pcDNA5 vector, and transfected into hMSCs and murine C3H10T1/2 mesenchymal cells, placed in pellet cultures and micromass cultures, respectively. The cultures were analyzed by reverse transcription-polymerase chain reaction for the expression of SCRG1 and cartilage marker genes, and by histological staining for cartilage phenotype. RESULTS: Induction of SCRG1 expression was seen during in vitro chondrogenesis, and was dependent on dexamethasone (DEX) known to promote chondrogenesis. Immunohistochemistry revealed that SCRG1 protein was localized to the extracellular matrix. Forced expression of SCRG1 in hMSCs suppressed their proliferation, and stimulated chondrogenesis in C3H10T1/2 cells, confirmed by reduced collagen type I and elevated collagen type IIB expression. CONCLUSION: These results suggest that SCRG1 is involved in cell growth suppression and differentiation during DEX-dependent chondrogenesis. SCRG1 may be of utility in gene-mediated cartilage tissue engineering.

Aged↗
PubMed2005

Quantitative imaging of proteoglycan in cartilage using a gadolinium probe and microCT.

OBJECTIVE: Micro-computed tomography (microCT) imaging has the potential to allow the three-dimensional (3D) visualization of cartilage morphology. However, cartilage intensity on a microCT image is weak because cartilage does not strongly attenuate X-rays. This work was designed to demonstrate that exposure of cartilage to charged gadolinium compounds modifies the intensity to allow an improved visualization of cartilage morphology and the determination of proteoglycan content. DESIGN: Trypsin was used to deplete proteoglycan in bovine nasal cartilage disks. Disks were then exposed to Gd(3+), gadopentetate (Gd-DTPA(2-)), or gadoteridol (Gd-HP-DO3A), and imaged with microCT. The intensities of the disks were measured from the images and compared to the actual proteoglycan content determined with a dimethylmethylene blue assay. RESULTS: Treatment of naïve disks with 200 mM Gd(3+) for 24h at room temperature produced a 2.8-fold increase in intensity on microCT images. Similar treatment with 200 mM Gd-DTPA(2-) produced a 1.4-fold increase. After 2h of trypsin treatment at room temperature, the intensities of cartilage disks exposed to 20 0mM Gd(3+) decreased by 12%. Conversely, the intensities of trypsin-treated disks exposed to 200 mM Gd-DPTA(2-) increased by 15%. Trypsin treatment caused a 4% increase in the intensities of disks exposed to neutral Gd-HP-DO3A. The correlation between proteoglycan content and the microCT intensity of cartilage treated with Gd(3+) was very good (r(2)=0.81). CONCLUSIONS: Gadolinium and microCT allow an improved 3D visualization of cartilage and quantification of its proteoglycan content.

Animals↗
PubMed2006

Mechanical properties of articular cartilage covered by the meniscus.

OBJECTIVE: To investigate the mechanical properties and morphological characteristics of articular cartilage on the tibial plateau of human knees, including the region covered by the meniscus. DESIGN: Using a 1-mm diameter flat-ended cylindrical probe to apply a constant load (0.6 MPa) at specific sites on the tibial plateau, the mechanical properties of articular cartilage were studied using seven cadaver knees. Comparison was made between data obtained by the cartilage covered by the meniscus and that not covered. This was done for both the medial and lateral plateaus. Histological sections of the articular cartilage were also performed to study differences between cartilage from these regions of the tibial plateau. RESULTS: Compared to cartilage that was not covered by the meniscus, the articular cartilage beneath the meniscus showed a significantly (P<0.05) larger modulus by as much as 70%, and was less thick by about 40%. Also, the subchondral bone quantity and calcified layer thickness were observed to be significantly lesser in the regions covered by the meniscus. CONCLUSIONS: Our findings revealed a significant difference between the mechanical properties and associated structures of articular cartilage in the region covered by the meniscus compared with the articular cartilage not covered by the meniscus.

Aged↗
PubMed2006

Quantification of ankle articular cartilage topography and thickness using a high resolution stereophotography system.

OBJECTIVE: To describe the topography and to measure thicknesses, surface areas and volumes in the cartilage layers of the ankle. METHODS: Twelve cadaveric ankle joints were disarticulated and the cartilage surfaces of each bone were imaged with a highly accurate (+/-2 microm) stereophotography system (ATOS). The cartilage was then dissolved and the subchondral bone imaged. The geometric data were then used to measure the quantitative parameters in each cartilage layer. RESULTS: The mean cartilage volume across the 12 specimens ranged from 0.32+/-0.08 ml for the fibula to 2.44+/-0.48 ml for the talus. The mean thickness of both the talar (1.1+/-0.18 mm) and tibial (1.16+/-0.14 mm) cartilage was significantly thicker than the fibula (0.85+/-0.13 mm). The talus had the greatest mean maximum cartilage thickness (2.38+/-0.4 mm). CONCLUSIONS: The reported stereophotographic technique may be used as an independent gold standard for validation of the accuracy of quantitative cartilage measurements made using magnetic resonance imaging. The thickness distribution maps show that the thickest articular cartilage occurs over the talar shoulders where osteochondral lesions commonly occur and not in the centre of the talar dome as commonly believed.

Aged↗
PubMed2006

Disorders of acetabular labrum and articular cartilage in hip dysplasia: evaluation using isotropic high-resolutional CT arthrography with sequential radial reformation.

OBJECTIVE: Acetabular labral tear may predispose to adjacent articular cartilage disorder and hip osteoarthritis in patients with hip dysplasia. We evaluated the diagnostic ability of isotropic computed tomography (CT) arthrography with radial reformation technique for detection of acetabular labral and articular cartilage disorders, and evaluate those interactions in hip dysplasia. METHODS: Forty-one hips in 29 patients with hip dysplasia received CT arthrography with isotropic spatial resolution of 0.5mm. After processing of multiplanar radial reformation over the whole acetabular circumference, frequencies of labral tear and acetabular cartilage disorder were evaluated at six divided zones of the weight-bearing areas. Of the 41 hips, 20 hips underwent arthroscopic examinations, and sensitivity, specificity and accuracy for detecting labral tear and acetabular cartilage disorder by CT arthrography were calculated using the arthroscopic findings as the standard of reference. RESULTS: The sensitivity, specificity and accuracy of CT arthrography were 97%/87%/92% for labral tear and 88%/82%/85% for acetabular cartilage disorder, respectively, using arthroscopic findings as the reference. The CT arthrography showed significantly higher frequency of labral and acetabular cartilage disorders at the anterior zones. Those zones with labral tear had significantly higher frequency of adjacent cartilage disorder than zones without labral tear. CONCLUSIONS: Isotropic CT arthrography with radial reformation technique allowed simultaneous, accurate assessment of labral and cartilage disorders in the whole acetabular circumference. Our findings indicated that labral tear is closely associated with adjacent cartilage disorder in hip dysplasia.

Acetabulum↗
PubMed2006

Evaluation of cartilage repair in the distal femur after autologous chondrocyte transplantation using T2 relaxation time and dGEMRIC.

OBJECTIVES: To investigate the potential of combining T2 relaxation time and delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) measurements after autologous chondrocyte transplantation (ACT). MATERIALS AND METHODS: T2 and dGEMRIC maps were measured in the sagittal and coronal directions in 12 patients 10-15 months after ACT surgery. Grafts were assessed for bulk full thickness, superficial and deep tissue T2 and dGEMRIC values, and were compared to control cartilage. RESULTS: All ACT grafts showed filling of the repair area to the level of or above the articular surface. Matrix of the grafts lacked the classical laminar structure and appeared more heterogenous on T2 maps than control cartilage. As compared to control cartilage, ACT grafts showed significantly longer T2 values for bulk tissue as well as for the superficial 50% and deep 50% of tissue except for superficial cartilage in the coronal direction. dGEMRIC assessment in the sagittal and coronal directions did not show a significant difference between bulk, superficial or deep tissue as compared to the control cartilage. Superficial and deep ACT tissue did not differ statistically in terms of their T2 or dGEMRIC values. CONCLUSIONS: These preliminary results suggest that, according to T2 measurements, ACT repair tissue at 10-15 months differs from normal cartilage and probably lacks the preferential collagen arrangement of normal cartilage, while according to dGEMRIC a varying degree of proteoglycan replenishment takes place. Combining these two quantitative magnetic resonance imaging techniques enables a more comprehensive characterization of cartilage repair than before.

Adult↗
PubMed2006

Different effects of high molecular weight sodium hyaluronate and NSAID on the progression of the cartilage degeneration in rabbit OA model.

OBJECTIVE: We examined the effects of nonsteroidal anti-inflammatory drug (NSAID) and intra-articular injections of sodium hyaluronate (HA) on cartilage degeneration in rabbit knee osteoarthritis (OA) model induced by partial meniscectomy. METHODS: Loxoprofen sodium (LOX) was used as the NSAID, administered p.o. once daily for 14 days at a dose of 4 mg/kg, starting from the day of meniscectomy. Suvenyl(SVE) was used as the high molecular weight HA, injected intra-articularly into injured knee every 3 days from the day of surgery. The effect on pain was assessed by an Incapacitance Tester, and the damage of cartilage was evaluated by visual assessment and histopathology at 14 days after the surgery. RESULTS: Hind paw weight bearing on the injured paw decreased time-dependently in the control group. In other three groups, the decrease of hind paw weight distribution was suppressed, demonstrating an analgesic effect. Visible damage and histopathological findings of cartilage degeneration were evident in the cartilages of the control group at day 14. In the SVE group, the damaged cartilage area decreased and cartilage degeneration was ameliorated. In contrast, in the LOX group, the cartilage degeneration was augmented compared with the control group. And, this exacerbated cartilage degeneration induced by LOX was reversed by the concomitant use of SVE. CONCLUSION: Our data show that the treatment with high molecular weight HA from earlier stage is strongly recommended to preserve the structure of cartilage.

Adjuvants, Immunologic↗
PubMed2006

Effects of estrogen on chondrocyte proliferation and collagen synthesis in skeletally mature articular cartilage.

PURPOSE: Estrogen has been shown to have a modulating effect on cartilage thickness. This investigation was performed to determine the effects of estrogen supplementation on cartilage thickness, cellular proliferation, and type II and X collagen production in skeletally mature rat cartilage, both in an organ culture and cell culture system. MATERIALS AND METHODS: Mandibular condyles were harvested from 8-week-old female Sprague Dawley rats and placed into tissue culture plates containing culture media with or without 17beta-estradiol supplementation. Organ cultures were labeled with 5-bromo-2'-deoxyuridine on culture day 2 or 4 to determine the effects of estrogen supplementation on the cellular mitotic index. Histomorphometric analysis of the organ culture sections was used to determine the thickness (microm) of the various cartilage zones, as well as the total cartilage thickness following estrogen exposure. Type X collagen was immunohistochemically identified in the ECM of hypertrophic chondrocytes using a rabbit anti-rat collagen type X antibody raised against the NCl domain. The reaction was visualized with an avidin-biotin peroxidase detection system (Vector Laboratories, Burlingame, CA). In a separate experiment, articulating cartilage chondrocytes were harvested by collagenase digestion and cultured at 5 x 10(5) cells per 35 mm tissue culture plate. Second subculture chondrocytes were divided into 2 groups: controls and [10(-8) M] 17beta-estradiol (E(2)-10(-8) M) and grown to confluence. The cell cultures were used to establish growth curves for each group using cell counts at 2-day intervals. RESULTS: In the organ culture experiment, 17beta-estradiol-treated condyles had a significant decrease in total cartilage thickness after 4 days in culture (P < .05). Estrogen supplementation resulted in a significant reduction in the mitotic index as early as culture day 2 (P < .05). Type X collagen deposition into the extracellular matrix was visibly increased in the hypertrophic chondrocyte zone for the estrogen-supplemented group on experimental days 2 and 4 compared with the control group. In the cell culture system, 17beta-estradiol [10(-8) M] decreased chondrocyte proliferation during logarithmic growth (P < .05) and at confluence (P < .05). CONCLUSION: These data show that estrogen decreased cartilage thickness by inhibition of chondrocyte proliferation and increased chondrocyte maturation. These observed effects showed the potential role of estrogen in the modulation of skeletally mature cartilage.

Animals↗
PubMed2005

Dual transduction of insulin-like growth factor-I and interleukin-1 receptor antagonist protein controls cartilage degradation in an osteoarthritic culture model.

This study evaluated the potential of gene induced synoviocyte expression of a combination of insulin-like growth factor-I (AdIGF-I) and interleukin-1 receptor antagonist protein (AdIL-1Ra) to control articular cartilage degradation in vitro. Cartilage explants and synovial membrane were harvested from young mature horses. Synovial monolayers were established and either (1) maintained as untransduced controls; (2) transduced with AdIGF-I at 200 MOI in 500 microl serum-free medium; (3) transduced with AdIL-1Ra at 100 MOI; or (4) transduced with a combination of AdIGF-I (200 MOI) and AdIL-1Ra (100 MOI). Following transduction, cartilage explants were exposed to the synovial monolayer medium using co-culture inserts. Cultures were maintained for 6 days in either serum-free medium or medium containing 10 ng/ml recombinant human interleukin-1beta. At termination, synovial cell RNA was isolated for real-time PCR analysis, and cartilage explants were collected for H&E and toluidine blue staining, immunohistochemistry for type II collagen and IGF-I, in situ localization of IGF-I and type II collagen gene expression, and biochemical assays. Synovial monolayers were readily transduced with both AdIGF-I and AdIL-1Ra. IGF-I and IL-1Ra protein were secreted at beneficial levels throughout the experiment, having peak concentrations of 94.6 ng/ml and 33.0 ng/ml, respectively. Transduction with IGF-I promoted cartilage production of proteoglycan and type II collagen, suggesting a beneficial role for healing injured cartilage. Transduction with IL-1Ra decreased the synovial expression of IL-1alpha and IL-1beta and matrix metalloproteinases, indicating a mechanism for prevention of matrix degradation. The beneficial effects of the combination of anabolic growth factors and catabolic blockers were evident in improved preservation of proteoglycan content of cartilage explants exposed to the depleting effects of IL-1. These results show that gene therapy combining anabolic growth factors to stimulate matrix synthesis and catabolic blockers to prevent matrix degradation by IL-1, protects and causes partial restoration of cartilage matrix, and suggest a potential benefit of combination gene therapy for cartilage healing.

Animals↗
PubMed2005

Cartilage degeneration in post-collapse cases of osteonecrosis of the human femoral head: altered mechanical properties in tension, compression, and shear.

Osteonecrosis, or avascular necrosis, is a painful and debilitating condition characterized by progressive joint degeneration subsequent to collapse of necrotic regions of trabecular bone. A clear understanding of the mechanism of cartilage degeneration in osteonecrosis is critical to the development of treatment strategies aimed at sparing the femoral head. An analysis of 13 post-collapse osteonecrotic (ON) human femoral heads was performed relative to 24 non-ON controls to determine quantitatively the biomechanical and histological properties of post-collapse osteonecrotic cartilage. Cartilage mechanical properties were measured in tension, compression, and shear at different sites on the femoral head and correlated to histologic measures of cartilage degeneration using a semi-quantitative grading scale. Decreasing cartilage tensile strength correlated with histologic evidence of degeneration in the ON group; however, less correlation was noted with shear and compressive properties. After statistical correction for the more severe histologic degeneration in the ON group, the non-ON samples were found to exhibit significantly smaller loss angles during shear testing, while samples from the ON group were found to have greater tensile strength. Similarly, the ON group was found to exhibit significantly greater proteoglycan loss while the non-ON group showed significantly increased surface fibrillation. This study provides evidence that the changes occurring in post-collapse cases of osteonecrosis may involve mechanisms other than those typically attributed to osteoarthritic degeneration. One potential explanation is that decreased loading of cartilage overlying collapsed ON lesions leads to proteoglycan loss similar to that occurring with cartilage disuse. Unlike degenerative changes, some articular cartilage changes caused by disuse may be reversible. The presence of reversible changes would likely increase the chances of success of head sparing treatment strategies that rely on the viability and mechanical integrity of the articular cartilage.

Adult↗
PubMed2006

Histologic evaluation of intracordal autologous cartilage injection in the paralyzed canine vocal fold at two and three years.

OBJECTIVE: Intracordal injection for vocal fold augmentation is easy and simple and does not require a cervical skin incision. We reported previously on the 1-year results of injected autologous auricular cartilage for volumetric augmentation in paralyzed canine vocal cord. This study evaluates the long-term histomorphologic results of injected autologous auricular cartilage for the augmentation of the paralyzed canine vocal fold at 2 and 3 years. STUDY DESIGN AND SETTING: A prospective trial of autologous cartilage augmentation of vocal cord in animal model. Five dogs were operated on. A piece of auricular cartilage was harvested from the ear and minced into tiny chips with a scalpel. Fat was harvested from inguinal area and minced with a scalpel. The minced cartilage and fat-paste (0.2 ml) was injected using a pressure syringe into the paralyzed thyroarytenoid muscle using direct laryngoscopy. Three animals were sacrificed at 2 years, two at 3 years. Each subject underwent laryngectomy and serial coronal sections of paraffin blocks from the posterior vocal fold were made. RESULTS: There was no significant complications perioperatively or postoperatively. The injected cartilage that seemed to have lost viability existed in the vocalis muscles until 36 months. Fibrotic change was exhibited in the surrounding injected cartilage. There were no differences between 2 and 3 years in histomorphologic results of the injected cartilage. CONCLUSION: The autologous auricular cartilage graft is well tolerated and may be a very effective material for long-term volumetric augmentation in the paralyzed vocal cord. EBM RATING: C-4.

Animals↗