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 1,279 records · Page 71Linked to original sources
PubMed2005

[Cartilage tissue engineering: state-of-the-art and future approaches].

Lesions of the articular cartilage have a large variety of causes among which traumatic damage, osteoarthritis and osteochondritis dissecans are the most frequent. Returning damaged cartilage in articular joints back to a functionally normal state has been a major challenge for orthopaedic surgeons. This interest results in large part because cartilage defects cannot adequately heal themselves. Current techniques used in orthopaedic practice to repair cartilage give variable and unpredictable results. Bone marrow stimulation techniques such as abrasion arthroplasty, drilling and microfracture produce mostly fibrocartilage. Autologous osteochondral transplant systems (mosaicplasty) have shown encouraging results. Autologous chondrocyte transplantation has led to a hyaline articular cartilage repair but little is known about the predictability and reliability of the procedure. The rapidly emerging field of tissue engineering promises creation of viable substitutes for failing cartilage tissue. Current tissue engineering approaches are mainly focused on the restoration of pathologically altered tissue structure based on the transplantation of cells in combination with supportive matrices and molecules. Among natural and synthetic matrices, collagen and polysaccharidic biomaterials have been extensively used with promising results. Recently, interest has switched to the use of mesenchymal stem cells instead of chondrocytes. Tissue engineering offers the possibility to treat localised cartilage lesions. Genetic engineering techniques using genetically modified chondrocytes offer also the opportunity to treat diffuse cartilage lesions occurring in osteoarthritis or inflammatory joint diseases. Electroporation is specially a reliable and inexpensive technique that shares with electrochemotherapy an ability to target the chondrocytes despite the barrier effect of the extracellular matrix without viral vectors. The authors review recent research achievements and highlight the potential clinical applications of new technologies in the treatment of patients with cartilage injuries.

Animals↗
PubMed2003

Magnetic resonance imaging of hyaline cartilage regeneration in neocartilage graft implantation.

BACKGROUND: The purpose of this study was to investigate the regenerative potential of hyaline cartilage in a neocartilage graft implant with the aid of MR cartilage imaging using a rabbit model. METHODS: Surgical osteochondral defects were created in the femoral condyles of 30 mature New Zealand rabbits. The findings of neocartilage in autologous cartilage grafts packed into osteochondral defects were compared with control group of no implant to the osteochondral defect. The outcome of the implantations was correlated with histologic and MR cartilage imaging findings over a 3-month interval. RESULTS: Neocartilage grafts packed into osteochondral defects showed regeneration of hyaline cartilage at the outer layer of the implant using MR cartilage imaging. Fibrosis of fibrocartilage developed at the outer layer of the autologous cartilage graft together with an inflammatory reaction within the osteochondral defect. CONCLUSION: This animal study provides evidence of the regenerative ability of hyaline cartilage in neocartilage transplants to repair articular cartilage.

Animals↗
PubMed2005

Triticeous cartilage: prevalence on panoramic radiographs and diagnostic criteria.

OBJECTIVES: To determine (1) the prevalence of calcified triticeous cartilage on panoramic radiographs of subjects older than 40 years of age, (2) the age and sex distribution of the subjects who have calcified triticeous cartilage, and (3) if the shape of triticeous cartilage differs from that of calcified carotid atheroma. STUDY DESIGN: In this retrospective study, triticeous cartilages were diagnosed from 847 panoramic radiographs. The shapes of triticeous cartilages and calcified carotid atheromas were determined using SigmaScan software. RESULTS: Prevalence of triticeous cartilage was 5.0% in males and 12.0% in females. The prevalence was 9.3% in the 40- to 60-year-old group (n=464) and 7.8% in the group older than 60 years (n=383). The triticeous cartilages were oval with smooth borders, whereas calcified carotid atheromas were mostly linear. CONCLUSIONS: Calcified triticeous cartilage was more prevalent in females. The prevalence was not age dependent. Shape, outline, and location of the triticeous cartilage can help in differentiating it from a carotid atheroma.

Adult↗
PubMed2001

Role of activatory Fc gamma RI and Fc gamma RIII and inhibitory Fc gamma RII in inflammation and cartilage destruction during experimental antigen-induced arthritis.

IgG-containing immune complexes, which are found in most RA joints, communicate with hematopoietic cells using three classes of Fc receptors(Fc gamma RI, -II, -III). In a previous study we found that if a chronic T-cell-mediated antigen-induced arthritis (AIA) was elicited in knee joints of FcR gamma-chain-deficient mice that lack functional Fc gamma RI and Fc gamma RIII, joint inflammation was comparable but severe cartilage destruction was absent. We now examined the individual role of the stimulatory Fc gamma RI and Fc gamma RIII and inhibitory Fc gamma RII in inflammation and functional cartilage damage in knee joints with AIA using Fc gamma RI-, Fc gamma RII-, and Fc gamma RIII-deficient mice. Three weeks after immunization with the antigen-methylated bovine serum albumin (BSA), cellular (T-cell responses as measured by lymphocyte proliferation) immunity raised against mBSA was comparable in all groups examined. Humoral (total IgG, IgG1, IgG2a, and IgG2b levels) immunity against mBSA was comparable in Fc gamma RI-/- and Fc gamma RIII-/- but higher in Fc gamma RII-/- if compared to controls. Joint swelling as measured by (99m)Tc uptake at days 1, 3, and 7 was similar in Fc gamma RI-/- and Fc gamma RIII-/- mice and significantly higher in Fc gamma RII-/-. Chronic inflammation and cartilage damage (depletion of proteoglycans, metalloproteinase (MMP)-induced neoepitopes, and matrix erosion) was studied histologically in total knee joint sections stained with hematoxylin or safranin-O. Histologically, at day 7 after AIA induction, exudate and infiltrate in the knee joint was similar in Fc gamma RI-/- and Fc gamma RIII-/- and significantly higher (230% and 340%) in Fc gamma RII-/- mice if compared to controls. Aggrecan breakdown in cartilage caused by MMPs and, which is related to severe irreversible cartilage erosion, was further studied by immunolocalization of MMP-mediated neoepitopes (VDIPEN) and image analysis. MMP-induced neoepitopes determined in various cartilage layers (tibia and femur) were primarily inhibited in Fc gamma RI-/- (79 to 87% and 87 to 88%, respectively) and comparable in Fc gamma RIII-/-. VDIPEN neoepitopes were much higher (82 to 122% and 200 to 250%, respectively) in Fc gamma RII-/- mice. Initial depletion of proteoglycans was similar (60 to 100%) in all groups. In the chronic phase, cartilage matrix erosion in the lateral and medial tibia was significantly elevated in Fc gamma RII-/- (222% and 186%, respectively) but not in Fc gamma RI-/- or Fc gamma RIII-/- mice. These results suggest that during T-cell-mediated AIA, Fc gamma RI and Fc gamma RIII act in concert in acute and chronic inflammation whereas Fc gamma RI is the dominant FcR involved in severe cartilage destruction. Fc gamma RII is a crucial inhibiting factor in acute and chronic inflammation and cartilage erosion.

Amino Acid Sequence↗
PubMed2003

Short-term exposure of cartilage to blood results in chondrocyte apoptosis.

Studies have shown that joint bleeding leads to cartilage degradation independent of concurrent synovitis. We hypothesized that the blood-induced cartilage damage is because of increased chondrocyte apoptosis after short-term exposure of whole blood or isolated mononuclear cells plus red blood cells to cartilage. Human cartilage tissue samples were co-cultured for 4 days with whole blood (50% v/v) or with mononuclear cells plus red blood cells (50% v/v equivalents). Cartilage matrix proteoglycan synthesis ((35)SO(4)(2-) incorporation) was determined after 4 days as well as at day 16 (after a 12-day recovery period in the absence of any additions). To test the involvement of apoptosis a specific caspase-3 inhibitor (acDEVDcho, 0 to 500 micro mol/L) as well as a pan-caspase inhibitor (zVADfmk, 0 to 500 micro mol/L) were added. Chondrocyte apoptosis was evaluated by immunohistochemical staining of single-strand DNA and by terminal dUTP nick-end labeling. Cartilage co-cultured with whole blood as well as mononuclear cells plus red blood cells induced a long-term inhibition of proteoglycan synthesis (74% and 78% inhibition on day 16, respectively). Immunohistochemistry showed a threefold increase in apoptotic chondrocytes in cultures with 50% whole blood as well as with mononuclear cells plus red blood cells. Both the specific caspase-3 inhibitor and the pan-caspase inhibitor partially restored proteoglycan synthesis in the cartilage after blood exposure. This effect was accompanied by a decrease in the number of apoptotic chondrocytes. These data suggest that a single joint hemorrhage (a 4-day exposure of cartilage to 50% v/v blood) results in induction of chondrocyte apoptosis, responsible for the observed inability of the chondrocytes to restore the proteoglycan synthesis during recovery from a short-term exposure to blood. This reduced restoration could eventually lead to cartilage degeneration and ultimately joint destruction.

Apoptosis↗
PubMed2001

The fate of mechanically induced cartilage in an unloaded environment.

According to mechanobiologic theories, persistent intermittent mechanical stimulation is required to maintain differentiated cartilage. In a rat model for bone repair, we studied the fate of mechanically induced cartilage after unloading. In three groups of rats, regenerating mesenchymal tissue was submitted to different loading conditions in bone chambers. Two groups were immediately killed after loading periods of 3 or 6 weeks (the 3-group and the 6-group). The third group was loaded for 3 weeks and then kept unloaded for another 3 weeks (the (3 + 3)-group). Cartilage was found in all loaded groups. Without loading, cartilage does not appear in this model. In the 3-group there was no clear ongoing endochondral ossification, the 6-group showed ossification in 2 out of 5 cartilage containing specimens, and in the (3 + 3)-group all cartilage was undergoing ossification. These results suggest a tendency of the cartilage to be maintained also under unloaded conditions until it is reached by bone that can replace it through endochondral ossification.Additional measurements showed less amount of new bone in the loaded specimens. In most of the loaded specimens in the 3-group, necrotic bone fragments were seen embedded in the fibrous tissue layer close to the loading piston, indicating that bone tissue had been resorbed due to the hydrostatic compressive load. In some specimens, a continuous cartilage layer covered the end of the specimen and seemed to protect the underlying bone from pressure-induced resorption. We suggest that one of the functions of the cartilage forming in the compressive loaded parts of a bone callus is to protect the surrounding bone callus from pressure-induced fluid flow leading to resorption.

Animals↗
PubMed2002

Mechanically induced electrical potentials of articular cartilage.

While there is increasing evidence that chondrocytes are affected by mechanically induced stimuli, endogenous force-related electrical potentials within articular cartilage have been so far observed only in-vitro. Using a porcine ex-vivo model (German Land Race), 8 knee joints were explanted and exposed to mechanical force (up to 800 N) using a special device. Electrodes were inserted into the cartilage matrix. With an amplifier and an A/D transducer the changes of electrical voltage between the electrodes as well as those of the force were recorded online and simultaneously on a computer. Additionally, we located one pair of electrodes on the surface of the cartilage tissue to detect electrical fields outside the cartilage tissue. In relation to the applied force we observed that electrical potentials derived from inside and outside the articular cartilage showed a correspondence. When an alternating force with an amplitude of 360 N and a frequency of about 0.2 Hz was periodically applied, we measured peak amplitudes ranging from 2.1 to 5.5 mV within the cartilage tissue with electrical negativity within the weight bearing area of the cartilage tissue. The measured voltages depended on the applied force, the location of the electrodes, and on anatomical variations. We found an almost linear relation between the magnitude of the applied force and the recorded voltage. With the help of the electrodes located outside and within the cartilage tissue, we were able to show that force dependent fields are generated inside the cartilage. There are several theories explaining the origin of these electrical phenomena, many of them focusing on the negative charges of the proteoglycans in relation to the flow of interstitial fluid and ions under compression. However, the consequences of these phenomena are yet not clear.

Animals↗
PubMed2002

Osmotic loading to determine the intrinsic material properties of guinea pig knee cartilage.

Few methods exist to study cartilage mechanics in small animal joints due to the difficulties associated with handling small tissue samples. In this study, we apply an osmotic loading method to quantify the intrinsic material properties of articular cartilage in small animal joints. Cartilage samples were studied from the femoral condyle and tibial plateau of two-month old guinea pigs. Swelling strains were measured using confocal fluorescence scanning microscopy in samples subjected to osmotic loading. A histochemical staining method was developed and calibrated for quantification of negative fixed charge density in guinea pig cartilage. Site-matched swelling strain data and fixed charge density values were then used with a triphasic theoretical model for cartilage swelling to determine the uniaxial modulus of the cartilage solid matrix. Moduli obtained in this study (7.2 MPa femoral condyle; 10.8 MPa, tibial plateau) compare well with previously reported values for the tensile moduli of human and other animal cartilages determined from uniaxial tension experiments. This study provides the first available data for material properties and fixed charge density in cartilage from the guinea pig knee and suggests a promising method for tracking changes in cartilage mechanics in small animal models of degeneration.

Animals↗
PubMed1997

Non-invasive determination of cartilage thickness throughout joint surfaces using magnetic resonance imaging.

Data on articular cartilage thickness in the living are important for the design for computer models, aimed at preoperatively assessing the effect of surgical procedures on joint contact and load transmission, and for the calculation of cartilage material properties from its deformational behavior as determined during arthroscopy. A non-invasive method for measuring cartilage thickness in living subjects is, however, not available. A technique based on magnetic resonance imaging has therefore been tested for assessing articular cartilage thickness throughout joint surfaces. The accuracy is determined by comparing cartilage thickness maps obtained from three patellar specimens with a fat-suppressed three-dimensional gradient-echo sequence (resolution 2 x 0.31 x 0.31 mm) to those obtained with CT arthrography, A-mode ultrasound and anatomical sections. The distribution patterns are quantitatively compared using image analysis. The highest agreement was obtained for MRI and the sections (50% identical pixels), but all techniques yielded very similar results. On average, MR slightly underestimated the cartilage thickness compared with CT and the sections, and overestimated it compared with ultrasound. No evidence of differences in the degree of similarity could be detected in areas of thin and thick cartilage. We conclude that, if the resolution and accuracy of the method presented are considered acceptable, MRI is available for repeatable determination of topographical maps of articular cartilage thickness in living subjects. These data can be used to determine joint contact and stress in computer models and to calculate cartilage material properties in vivo.

Adult↗
PubMed1999

Sonographic imaging of normal and osteoarthritic cartilage.

OBJECTIVES: This study was undertaken to describe representative sonographic features of normal and osteoarthritic cartilage. METHODS: Sonographic evaluation was performed with real-time ultrasound equipment, using 7.5-, 10-, 13-, 15-, and 20-MHz transducers. Normal and osteoarthritic cartilage has been studied in healthy subjects and in patients with osteoarthritis. RESULTS: Ultrasonography allows a safe, quick, and careful evaluation of both normal and osteoarthritic cartilage. A spectrum of images ranging from loss of cartilage transparency to marked narrowing of the cartilage layer can be depicted clearly in patients with osteoarthritis. Loss of clarity of the cartilaginous band and loss of the normal sharpness of the synovial space-cartilage interface are the earlier features of cartilage damage. CONCLUSIONS: Although the value of ultrasonography in the evaluation of articular cartilage remains to be determined, this imaging method can be regarded as a useful bedside procedure for initial diagnostic screening of osteoarthritic femoral condylar cartilage.

Cartilage, Articular↗
PubMed1983

Structural changes during development in bovine fetal epiphyseal cartilage.

Sedimentation coefficients of approximately 150 S show that proteoglycan aggregates from bovine fetal epiphyseal cartilage are exceptionally large. To determine the structural basis for the unusually large size of these proteoglycan aggregates, identify changes in proteoglycan structure with changing developmental age, and provide a basis for demonstrating the structural modifications which may occur in growth plate proteoglycan aggregates during endochondral ossification, we examined the molecular architecture and dimensions of fetal epiphyseal proteoglycans by electron microscopy. The eight bovine epiphyseal cartilages studied ranged in fetal age from 168 to 241 days. Proteoglycans were extracted in 4 M guanidinium hydrochloride containing protease inhibitors and isolated by equilibrium density gradient centrifugation under associative and dissociative conditions. Electron micrographs were made from monolayer preparations of proteoglycan-cytochrome c mixtures on nitrocellulose support films. The overall molecular architecture of the proteoglycan aggregates from fetal epiphyseal cartilages was similar to that of aggregates from other cartilages and showed a single, unbranched central hyaluronic acid filament to which many proteoglycan monomers were attached. However, the dimensions of the fetal proteoglycans differed strikingly from those of proteoglycans from mature cow nasal or immature calf nasal cartilage. Specifically, proteoglycan aggregates from bovine fetal epiphyseal cartilage showed: (a) longer hyaluronic acid central filaments; (b) greater numbers of proteoglycan monomers per aggregate; (c) closer spacing of proteoglycan monomers along the hyaluronic acid central filament; and (d) longer proteoglycan monomer core proteins. Proteoglycan monomers bound to hyaluronate consisted of two segments: (1) a peripheral thick segment, composed of the chondroitin sulfate chains condensed along the peripheral portion of the protein core, which corresponds to the chondroitin sulfate-rich region; and, (2) a central thin segment, devoid of visible glycosaminoglycan chains, which attaches directly to the hyaluronic acid central filament and contains the hyaluronic acid binding region and a portion of the keratan sulfate-rich region. The contribution of the thin segment to total monomer length decreased as total monomer length increased. Thus, in longer monomers the thick segment contributed more to total monomer length and the thin segment contributed less. Both the thin and thick segments of monomers from fetal epiphyseal cartilage were longer than the corresponding segments of calf nasal cartilage and mature bovine nasal cartilage monomers.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1999

Effects of estrogen on the condylar cartilage of the rat mandible in organ culture.

PURPOSE: The effects of estrogen on bone have been well documented. However, very little is known about the regulatory role of estrogen on cartilage and, in particular, the secondary cartilage of the mandibular condyle. The aims of this study were to determine whether estrogen receptors are present in the condylar cartilage of the rat mandible and to assess the effect of varying 17beta-estradiol (E2) concentrations on the proteoglycan content of this tissue. MATERIALS AND METHODS: Mandibular condyles of 16 female Sprague-Dawley rats were resected. Eighteen of these condyles were divided into three groups and the condylar cartilage was removed and placed in organ culture for 4 days with media containing different concentrations of estrogen: 10(-11) mol/L, 10(-8) mol/L, and 10(-6) mol/L. The cartilage then was analyzed for proteoglycan content along with six specimens not passed through the organ culture. Six intact mandibular condyles also were resected and placed in organ culture with the same varying E2 concentrations, and the condylar cartilage was analyzed for estrogen receptors along with two condyles not passed through the culture system. RESULTS: Estrogen receptors were evenly distributed within the chondroblastic and hypertrophic zones in the control group and the group with 10(-11) mol/L E2. With E2 concentrations of 10(-8) mol/L and 10(-6) mol/L, there was a qualitative decrease in hypertrophic chondroblasts, thickness of the condylar cartilage, and a significant decrease in proteoglycan content. CONCLUSIONS: This study shows the presence of estrogen receptors in the secondary cartilage of the rat mandibular condyle. Estrogen has the potential to cause a decrease in extracellular matrix and thickness of this cartilage.

Analysis of Variance↗
PubMed2003

Speed of sound in normal and degenerated bovine articular cartilage.

The unknown and variable speed of sound may impair accuracy of the acoustic measurement of cartilage properties. In this study, relationships between the speed of sound and cartilage composition, mechanical properties and degenerative state were studied in bovine knee and ankle cartilage (n = 62). Further, the effect of speed variation on the determination of cartilage thickness and stiffness with ultrasound (US) indentation was numerically simulated. The speed of sound was significantly (n = 32, p < 0.05) dependent on the cartilage water content (r = -0.800), uronic acid content (per wet weight, r = 0.886) and hydroxyproline content (per wet weight, r = 0.887, n = 28), Young's modulus at equilibrium (r = 0.740), dynamic modulus (r = 0.905), and degenerative state (i.e., Mankin score) (r = -0.727). In addition to cartilage composition, mechanical and acoustic properties varied significantly between different anatomical locations. In US indentation, cartilage is indented with a US transducer. Deformation and thickness of tissue are calculated using a predefined speed of sound and used in determination of dynamic modulus. Based on the simulations, use of the mean speed of sound of 1627 m/s (whole material) induced a maximum error of 7.8% on cartilage thickness and of 6.2% on cartilage dynamic modulus, as determined with the US indentation technique (indenter diameter 3 mm). We believe that these errors are acceptable in clinical US indentation measurements.

Animals↗
PubMed1998

Evaluation of acoustical parameter sensitivity to age-related and osteoarthritic changes in articular cartilage using 50-MHz ultrasound.

The current study reports the sensitivity of acoustical parameters estimated at high frequency to the osteoarthritic morphological and structural changes in patellar cartilage in rat knees. Osteoarthritis (OA) was induced by a single intra-articular injection of mono-iodo-acetic acid in right knees. OA patellas and their contralateral controls were excised at regular intervals after injection and were examined in vitro with a scanning acoustical microscope operating with a poly(vinylidene di-fluoride) (PVDF) 80-MHz focused transducer. Cartilage thickness was estimated using B-scan images. The quantitative analysis of the radiofrequency signal backscattered by the cartilage was performed using integrated reflection coefficient (IRC) and apparent integrated backscatter (AIB), which were estimated in the 20-60-MHz frequency range. One week after injection, a cartilage thickness decrease was detected (-6%, on average) that preceded the significant hypertrophy (20.1%) that occurred 2 weeks after injection and could be due to tissue repair. From 1 week to 3 weeks after injection, the IRC of OA patellas was significantly lower than that of control patellas. The IRC difference increased with time from -3.3 +/- 2.4 dB at 1 week to -8.4 +/- 1.7 dB at 3 weeks. An AIB decrease was observed with time for both OA and control patellas (-2.9 to -4.2 dB per week). An AIB difference between OA and control patellas was detected from 1 week to 3 weeks after injection. This difference decreased with time. IRC variation reflects a change in acoustical impedance of the superficial layer of the cartilage and could be linked to a change in constituent content and/or to a disruption of fibers of the collagen network that led to the fibrillation of the cartilage surface. AIB variation reflects a change in shape, size and/or density of the scatterers and could be related to changes in the constituent content and in the organization of the matrix in the internal layer of the cartilage. IRC and AIB could provide information about the structural modifications of the cartilage due to osteoarthritis or to cartilage maturation.

Aging↗
PubMed1998

Immunohistochemical analysis of several proteolytic enzymes as parameters of cartilage degradation.

Osteoarthritis is the most common joint disease in humans. It is characterized by a gradual loss of extracellular matrix components of articular cartilage such as collagen and proteoglycan. Presently, however, emphasis is placed on enzymes exerting a strong influence on cartilage degradation. These enzymes include matrix metalloproteinases (MMP), their specific inhibitors (TIMP) and the plasminogen activator/inhibitor system. We applied monoclonal antibodies against MMP-1, -2, -3, -9 and their inhibitors TIMP-1/-2, as well as against urokinase-plasminogen activator u-PA and its inhibitor PAI to investigate their influence on articular cartilage degradation in patients with varusgonarthritis. We examined the cartilage of the lateral and medial compartments of 20 tibia plateaus, which can present with slight and severe cartilage degradations at the same time. In doing so, we tried to show whether or not immunohistological detection of enzymes could serve as a parameter for chondral degradation. The strongest immunoreaction for all enzymes was noted in the superficial layer of articular cartilage both medially and laterally. Between medial and lateral compartments, however, there were striking differences in the immunoreaction intensity of chondrocytes for MMP-1 and -3 as well as for TIMP-1 and u-PA. We noted that in cartilage with more advanced degradation, the immunoreaction for these enzymes was significantly higher in medial than in lateral compartments (p < 0.05). At the immunohistological level, a direct correlation between the grade of cartilage degradation and immunoreaction intensity was found. Our results corroborate the assumption that the expression of certain matrix-degradating enzymes serves as a parameter for the grade of cartilage degradation.

Aged↗
PubMed2001

Enhanced matrix synthesis and in vitro formation of cartilage-like tissue by genetically modified chondrocytes expressing BMP-7.

Bone morphogenic protein-7 (BMP-7) supports ectopic cartilage and bone formation, is expressed in normal articular cartilage, and increases matrix synthesis in chondrocytes. Based on this knowledge, we hypothesized that an adenovirus (Ad) vector encoding human BMP-7 could be used to modify chondrocytes genetically to improve their capacity for cartilage repair. An adenovirus vector encoding BMP-7 (AdBMP-7) was constructed and its bioactivity confirmed by ectopic bone formation assay. AdBMP-7 modification of bovine chondrocytes induced expression of BMP-7 mRNA and bioactive protein, resulting in an increase in incorporation of 35SO4- into proteoglycan, 3H-proline uptake into protein, and the expression of the cartilage-specific matrix genes, aggrecan and type II collagen. An in vitro model of chondrocyte transplantation was used to demonstrate the feasibility of using genetically modified chondrocytes to enhance formation of cartilage-like tissue. When transplanted onto cartilage explants and maintained in vitro for 3 weeks, chondrocytes modified with AdBMP-7 formed 1.9-fold thicker tissue than chondrocytes modified with a control vector (P < 0.001). This tissue was positive for type II collagen and proteoglycan but negative for type X collagen and demonstrated a cartilage-like morphology. These observations suggest that Ad-mediated transfer of BMP-7 gene to chondrocytes enhances the chondrocyte-specific matrix synthesis and their capacity to form cartilage-like tissue, thus representing a strategy that may improve cell-based cartilage repair.

Adenoviridae↗
PubMed2002

Altered swelling behavior of femoral cartilage following joint immobilization in a canine model.

Periods of reduced joint loading have been shown to induce changes in the biochemical composition. metabolism and mechanics of articular cartilage. In this study, changes in cartilage swelling behavior were studied following a 4-week period of joint immobilization, using a recently developed osmotic loading technique [J. Biomech, 32 (1999) 401-408]. The magnitude and distribution of swelling strains were measured in cartilage-bone samples equilibrated in physiological and hypotonic saline, relative to a hypertonic reference NaCl solution. Physicochemical parameters (glycosaminoglycan fixed charge density and water volume fraction) were determined in site-matched cartilage samples. The experimental data for swelling strains, fixed charge density and water volume fraction were used with a triphasic mechano-chemical theory [J. Biomech. Eng. 113 (1991) 245-258] to determine the effect of joint immobilization on the tensile modulus of the cartilage solid matrix. Four weeks of immobilization resulted in a significant increase in the magnitude of swelling-induced strains, and a significant decrease in fixed charge density in cartilage, as compared with the contralateral controls. Joint immobilization also resulted in decreases in values for the modulus of cartilage, as compared with the contralateral controls. Our results suggest that 4 weeks of joint immobilization had a significant effect on cartilage mechanical function that may be linked to collagen changes in the cartilage extracellular matrix.

Animals↗
PubMed1985

Effect of electrocautery on fresh human articular cartilage.

The use of high energy devices has been suggested for intra-articular surgery. Experimental studies have been performed using the laser and electrocautery. However, clinical application has primarily been with the use of the electrocautery. Electrosurgery is currently being used for lateral retinacular release as well as meniscal surgery. Inadvertent damage to articular cartilage may occur, especially during meniscal resection. The objective of the current study is to assess the effect of the Concept electrocautery with the meniscal cutting electrode on fresh human articular cartilage. Twenty fresh tibial plateaus removed at the time of total knee arthroplasty were subjected to electrocautery currents ranging from 25 to 82.5 W. The articular cartilage was stained with hematoxylin and eosin. The extent of cartilage necrosis was quantitated as a percentage of the thickness of the articular cartilage. A dose response curve was developed. The extent of articular cartilage necrosis with the electrocautery setting of 20 (24.4 W) commonly used for meniscal resection resulted in only an 11.4%-injury to the articular cartilage. At the manufacturer's recommended setting of 24 (27 W), a 16% depth of laceration of the articular cartilage may be anticipated. We conclude that the lowest current setting possible should be utilized for meniscal surgery and the risk of articular cartilage damage from inadvertent injury is not excessive.

Cartilage, Articular↗