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P A J Brama - One of the best experts on this subject based on the ideXlab platform.
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Composition, structure and tensile biomechanical properties of Equine Articular Cartilage during growth and maturation
Scientific Reports, 2018Co-Authors: Joonas Oinas, P A J Brama, Heikki J Helminen, A P Ronkainen, Lassi Rieppo, Mikko Finnila, Jarkko T Iivarinen, P. R. Weeren, R. K. Korhonen, S. SaarakkalaAbstract:Articular Cartilage undergoes structural and biochemical changes during maturation, but the knowledge on how these changes relate to Articular Cartilage function at different stages of maturation is lacking. Equine Articular Cartilage samples of four different maturation levels (newborn, 5-month-old, 11-month-old and adult) were collected ( N = 25). Biomechanical tensile testing, Fourier transform infrared microspectroscopy (FTIR-MS) and polarized light microscopy were used to study the tensile, biochemical and structural properties of Articular Cartilage, respectively. The tensile modulus was highest and the breaking energy lowest in the newborn group. The collagen and the proteoglycan contents increased with age. The collagen orientation developed with age into an arcade-like orientation. The collagen content, proteoglycan content, and collagen orientation were important predictors of the tensile modulus ( p
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influence of different exercise levels and age on the biochemical characteristics of immature Equine Articular Cartilage
Equine Veterinary Journal, 2010Co-Authors: P A J Brama, Ruud A Bank, J M Tekoppele, P. R. Weeren, A BarneveldAbstract:Summary This study aimed to examine whether biochemical characteristics of juvenile Articular Cartilage are changing during the first year post partum and whether they can be influenced by exercise at young age. Water, glycosaminoglycan (GAG), DNA, total collagen, hydroxylysine and hydroxylysylpyridinoline (HP) content were measured in Articular Cartilage of 43 foals that were subdivided into 3 groups (n = 15, 14 and 14) which were subjected to different exercise regimens from one week after birth to age 5 months. At the age of 5 months all foals were weaned and 8 foals were selected randomly from each exercise group and subjected to euthanasia. The remaining foals (n = 19) were grouped and subjected to a similar exercise regimen for an additional 6 months. Differences were tested by student's t test (P<0.01). No effect of exercise on the water or DNA content was found. GAG content increased with increasing exercise in the 5 months group. These differences had disappeared after 6 months of similar exercise. No influence of exercise could be demonstrated on any of the collagen parameters. When comparing 5 months with 11 months group, all parameters except hydroxylysine changed significantly during these 6 months. Water, DNA and GAG content decreased during maturation. Collagen and HP content increased. It is hypothesised that juvenile Equine Articular Cartilage may be seen as a dynamic, continuously remodelling tissue that is gradually taking on the biochemical characteristics it will have during the rest of the life of the animal. Moderate exercise does not influence the collagen component of the extracellular matrix. It has a beneficial, but reversible, effect on the glycosaminoglycan component.
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functional adaptation of Equine Articular Cartilage the formation of regional biochemical characteristics up to age one year
Equine Veterinary Journal, 2010Co-Authors: P A J Brama, Ruud A Bank, J M Tekoppele, A Barneveld, P R Van WeerenAbstract:Biochemical heterogeneity of Cartilage within a joint is well known in mature individuals. It has recently been reported that heterogeneity for proteoglycan content and chondrocyte metabolism in sheep develops postnatally under the influence of loading. No data exist on the collagen network in general or on the specific situation in the horse. The objective of this study was to investigate the alterations in Equine Articular Cartilage biochemistry that occur from birth up to age one year, testing the hypothesis that the molecular composition of Equine Cartilage matrix is uniform at birth and biochemical heterogeneity is formed postnatally. Water content, DNA content, glycosaminoglycan content (GAG) and biochemical characteristics of the collagen network (collagen content, hydroxylysine content and hydroxylysylpyridinoline [HP] crosslinks) were measured in immature Articular Cartilage of neonatal (n = 16), 5-month-old foals (n = 16) and yearlings (n = 16) at 2 predefined differently loaded sites within the metacarpophalangeal joint. Statistical differences between sites were analysed by ANOVA (P<0.01), and age correlation was tested by Pearson's product moment correlation analysis (P<0.01). In neonatal Cartilage no significant site differences were found for any of the measured biochemical parameters. This revealed that the horse has a biochemically uniform joint (i.e. the Cartilage) at birth. In the 5-month-old foals and yearlings, significant site differences, comparable to those in the mature horse, were found for DNA, GAG, collagen content and hydroxylysine content. This indicates that functional adaptation of Articular Cartilage to weight bearing for these biochemical parameters takes place during the first months postpartum. Water content and HP crosslinks showed no difference between the 2 sites from neonatal horses, 5-month-old animals and yearlings. At both sites water, DNA and GAG decreased during maturation while collagen content, hydroxylysine content and HP crosslinks increased. We propose that a foal is born with a uniform biochemical composition of Cartilage in which the functional adaptation to weight bearing takes place early in life. This adaptation results in biochemical and therefore biomechanical heterogeneity and is thought to be essential to resist the different loading conditions to which Articular Cartilage is subjected during later life. As collagen turnover is extremely low at mature age, an undisturbed functional adaptation of the collagen network of Articular Cartilage at a young age may be of significant importance for future strength and resistance to injury.
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changes in collagen fibril network organization and proteoglycan distribution in Equine Articular Cartilage during maturation and growth
Journal of Anatomy, 2009Co-Authors: Mika M Hyttinen, Heikki J Helminen, Jaakko Holopainen, Rene P Van Weeren, E C Firth, P A J BramaAbstract:The aim of this study was to record growth-related changes in collagen network organization and proteoglycan distribution in intermittently peak-loaded and continuously lower-level-loaded Articular Cartilage. Cartilage from the proximal phalangeal bone of the Equine metacarpophalangeal joint at birth, at 5, 11 and 18 months, and at 6–10 years of age was collected from two sites. Site 1, at the joint margin, is unloaded at slow gaits but is subjected to high-intensity loading during athletic activity; site 2 is a continuously but less intensively loaded site in the centre of the joint. The degree of collagen parallelism was determined with quantitative polarized light microscopy and the parallelism index for collagen fibrils was computed from the Cartilage surface to the osteochondral junction. Concurrent changes in the proteoglycan distribution were quantified with digital densitometry. We found that the parallelism index increased significantly with age (up to 90%). At birth, site 2 exhibited a more organized collagen network than site 1. In adult horses this situation was reversed. The superficial and intermediate zones exhibited the greatest reorganization of collagen. Site 1 had a higher proteoglycan content than site 2 at birth but here too the situation was reversed in adult horses. We conclude that large changes in joint loading during growth and maturation in the period from birth to adulthood profoundly affect the architecture of the collagen network in Equine Cartilage. In addition, the distribution and content of proteoglycans are modified significantly by altered joint use. Intermittent peak-loading with shear seems to induce higher collagen parallelism and a lower proteoglycan content in Cartilage than more constant weight-bearing. Therefore, we hypothesize that the formation of mature Articular Cartilage with a highly parallel collagen network and relatively low proteoglycan content in the peak-loaded area of a joint is needed to withstand intermittent stress and shear, whereas a constantly weight-bearing joint area benefits from lower collagen parallelism and a higher proteoglycan content.
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effect of loading on the organization of the collagen fibril network in juvenile Equine Articular Cartilage
Journal of Orthopaedic Research, 2009Co-Authors: P A J Brama, Heikki J Helminen, Jaakko Holopainen, Rene P Van Weeren, E C Firth, Mika M HyttinenAbstract:We investigated the effects of exercise-induced loading on the collagen network of Equine Articular Cartilage. Collagen fibril architecture at a site (1) subjected to intermittent high-intensity loading was compared with that of an adjacent site (2) sustaining continuous low-level load. From horses exposed to forced exercise (CONDEX group) or not (PASTEX group), the spatial parallelism of fibrils and the orientation angle between fibrils and the surface at depths 9 µm apart through Cartilage from surface to tidemark were determined using polarized light microscopy, and expressed as parallelism index (PI) and orientation index (OI). PI was significantly higher in site 2 than 1 in CONDEX and PASTEX groups. PI was significantly higher in forced exercised horses at site 2 but not site 1. OI was significantly greater (more perpendicular to the surface) in the superficial and deep Cartilage of site 2 than 1 in both CONDEX and PASTEX groups. Superficial zone OI was higher in exercised horses at site 1 but not at site 2. Exercise increased collagen parallelism and affected orientation. The site differences in OI indicate that Benninghoff's classic predominantly perpendicular arcades appear not to be a consistent architectural feature, but adapt to local forces sustained. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Mika M Hyttinen - One of the best experts on this subject based on the ideXlab platform.
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changes in collagen fibril network organization and proteoglycan distribution in Equine Articular Cartilage during maturation and growth
Journal of Anatomy, 2009Co-Authors: Mika M Hyttinen, Heikki J Helminen, Jaakko Holopainen, Rene P Van Weeren, E C Firth, P A J BramaAbstract:The aim of this study was to record growth-related changes in collagen network organization and proteoglycan distribution in intermittently peak-loaded and continuously lower-level-loaded Articular Cartilage. Cartilage from the proximal phalangeal bone of the Equine metacarpophalangeal joint at birth, at 5, 11 and 18 months, and at 6–10 years of age was collected from two sites. Site 1, at the joint margin, is unloaded at slow gaits but is subjected to high-intensity loading during athletic activity; site 2 is a continuously but less intensively loaded site in the centre of the joint. The degree of collagen parallelism was determined with quantitative polarized light microscopy and the parallelism index for collagen fibrils was computed from the Cartilage surface to the osteochondral junction. Concurrent changes in the proteoglycan distribution were quantified with digital densitometry. We found that the parallelism index increased significantly with age (up to 90%). At birth, site 2 exhibited a more organized collagen network than site 1. In adult horses this situation was reversed. The superficial and intermediate zones exhibited the greatest reorganization of collagen. Site 1 had a higher proteoglycan content than site 2 at birth but here too the situation was reversed in adult horses. We conclude that large changes in joint loading during growth and maturation in the period from birth to adulthood profoundly affect the architecture of the collagen network in Equine Cartilage. In addition, the distribution and content of proteoglycans are modified significantly by altered joint use. Intermittent peak-loading with shear seems to induce higher collagen parallelism and a lower proteoglycan content in Cartilage than more constant weight-bearing. Therefore, we hypothesize that the formation of mature Articular Cartilage with a highly parallel collagen network and relatively low proteoglycan content in the peak-loaded area of a joint is needed to withstand intermittent stress and shear, whereas a constantly weight-bearing joint area benefits from lower collagen parallelism and a higher proteoglycan content.
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effect of loading on the organization of the collagen fibril network in juvenile Equine Articular Cartilage
Journal of Orthopaedic Research, 2009Co-Authors: P A J Brama, Heikki J Helminen, Jaakko Holopainen, Rene P Van Weeren, E C Firth, Mika M HyttinenAbstract:We investigated the effects of exercise-induced loading on the collagen network of Equine Articular Cartilage. Collagen fibril architecture at a site (1) subjected to intermittent high-intensity loading was compared with that of an adjacent site (2) sustaining continuous low-level load. From horses exposed to forced exercise (CONDEX group) or not (PASTEX group), the spatial parallelism of fibrils and the orientation angle between fibrils and the surface at depths 9 µm apart through Cartilage from surface to tidemark were determined using polarized light microscopy, and expressed as parallelism index (PI) and orientation index (OI). PI was significantly higher in site 2 than 1 in CONDEX and PASTEX groups. PI was significantly higher in forced exercised horses at site 2 but not site 1. OI was significantly greater (more perpendicular to the surface) in the superficial and deep Cartilage of site 2 than 1 in both CONDEX and PASTEX groups. Superficial zone OI was higher in exercised horses at site 1 but not at site 2. Exercise increased collagen parallelism and affected orientation. The site differences in OI indicate that Benninghoff's classic predominantly perpendicular arcades appear not to be a consistent architectural feature, but adapt to local forces sustained. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
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effect of loading on the organization of the collagen fibril network in juvenile Equine Articular Cartilage
Journal of Orthopaedic Research, 2009Co-Authors: P A J Brama, Heikki J Helminen, Jaakko Holopainen, Rene P Van Weeren, E C Firth, Mika M HyttinenAbstract:We investigated the effects of exercise-induced loading on the collagen network of Equine Articular Cartilage. Collagen fibril architecture at a site (1) subjected to intermittent high-intensity loading was compared with that of an adjacent site (2) sustaining continuous low-level load. From horses exposed to forced exercise (CONDEX group) or not (PASTEX group), the spatial parallelism of fibrils and the orientation angle between fibrils and the surface at depths 9 microm apart through Cartilage from surface to tidemark were determined using polarized light microscopy, and expressed as parallelism index (PI) and orientation index (OI). PI was significantly higher in site 2 than 1 in CONDEX and PASTEX groups. PI was significantly higher in forced exercised horses at site 2 but not site 1. OI was significantly greater (more perpendicular to the surface) in the superficial and deep Cartilage of site 2 than 1 in both CONDEX and PASTEX groups. Superficial zone OI was higher in exercised horses at site 1 but not at site 2. Exercise increased collagen parallelism and affected orientation. The site differences in OI indicate that Benninghoff's classic predominantly perpendicular arcades appear not to be a consistent architectural feature, but adapt to local forces sustained.
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influence of exercise and joint topography on depth related spatial distribution of proteoglycan and collagen content in immature Equine Articular Cartilage
Equine Veterinary Journal, 2009Co-Authors: P A J Brama, Heikki J Helminen, Jaakko Holopainen, E C Firth, P. R. Weeren, Mika M HyttinenAbstract:Summary Reasons for performing study: There is ample evidence on topographical heterogeneity of the principal biochemical components of Articular Cartilage over the surface of the joint and the influence of loading thereon, but no information on depth-related zonal variation in horses. Objectives: To study depth-related zonal variation in proteoglycan (PG) and collagen content in Equine Articular Cartilage. Methods: Two techniques (safranin-O densitometry and Fourier transform infrared spectroscopy) were applied to sections of Articular Cartilage from the proximal phalangeal bone of the metacarpophalangeal joint of 18-month-old Thoroughbreds that had been raised at pasture from age 0–18 months without (PASTEX) and with (CONDEX) additional exercise. Two sites were investigated: site 1 at the joint margin that is unloaded at rest or at slow gaits, but subjected to high-intensity loading during athletic activity; and site 2, a continuously, but less intensively, loaded site in the centre of the joint. Results: Proteoglycan values increased from the surface to the deep layers of the Cartilage, collagen content showed a reverse pattern. PG content was significantly higher at site 2 in both PASTEX and CONDEX animals without an effect of exercise. In the PASTEX animals collagen content was significantly higher at site 1, but in the CONDEX group the situation was reversed, due to a significant exercise effect on site 1, leading to a reduced collagen content. Conclusions: Collagen and PG content gradients agree with findings in other species. The observations on PG levels suggest that the exercise level was not strenuous. The collagen results in the PASTEX group confirmed earlier findings, the lower levels at site 1 in the CONDEX group being possibly due to an advancement of the physiological maturation process of collagen remodelling. Potential relevance: This study confirms earlier observations that even moderate variations in exercise level in early age may have significant effects on the collagen network of Articular Cartilage.
Heikki J Helminen - One of the best experts on this subject based on the ideXlab platform.
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Composition, structure and tensile biomechanical properties of Equine Articular Cartilage during growth and maturation
Scientific Reports, 2018Co-Authors: Joonas Oinas, P A J Brama, Heikki J Helminen, A P Ronkainen, Lassi Rieppo, Mikko Finnila, Jarkko T Iivarinen, P. R. Weeren, R. K. Korhonen, S. SaarakkalaAbstract:Articular Cartilage undergoes structural and biochemical changes during maturation, but the knowledge on how these changes relate to Articular Cartilage function at different stages of maturation is lacking. Equine Articular Cartilage samples of four different maturation levels (newborn, 5-month-old, 11-month-old and adult) were collected ( N = 25). Biomechanical tensile testing, Fourier transform infrared microspectroscopy (FTIR-MS) and polarized light microscopy were used to study the tensile, biochemical and structural properties of Articular Cartilage, respectively. The tensile modulus was highest and the breaking energy lowest in the newborn group. The collagen and the proteoglycan contents increased with age. The collagen orientation developed with age into an arcade-like orientation. The collagen content, proteoglycan content, and collagen orientation were important predictors of the tensile modulus ( p
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changes in collagen fibril network organization and proteoglycan distribution in Equine Articular Cartilage during maturation and growth
Journal of Anatomy, 2009Co-Authors: Mika M Hyttinen, Heikki J Helminen, Jaakko Holopainen, Rene P Van Weeren, E C Firth, P A J BramaAbstract:The aim of this study was to record growth-related changes in collagen network organization and proteoglycan distribution in intermittently peak-loaded and continuously lower-level-loaded Articular Cartilage. Cartilage from the proximal phalangeal bone of the Equine metacarpophalangeal joint at birth, at 5, 11 and 18 months, and at 6–10 years of age was collected from two sites. Site 1, at the joint margin, is unloaded at slow gaits but is subjected to high-intensity loading during athletic activity; site 2 is a continuously but less intensively loaded site in the centre of the joint. The degree of collagen parallelism was determined with quantitative polarized light microscopy and the parallelism index for collagen fibrils was computed from the Cartilage surface to the osteochondral junction. Concurrent changes in the proteoglycan distribution were quantified with digital densitometry. We found that the parallelism index increased significantly with age (up to 90%). At birth, site 2 exhibited a more organized collagen network than site 1. In adult horses this situation was reversed. The superficial and intermediate zones exhibited the greatest reorganization of collagen. Site 1 had a higher proteoglycan content than site 2 at birth but here too the situation was reversed in adult horses. We conclude that large changes in joint loading during growth and maturation in the period from birth to adulthood profoundly affect the architecture of the collagen network in Equine Cartilage. In addition, the distribution and content of proteoglycans are modified significantly by altered joint use. Intermittent peak-loading with shear seems to induce higher collagen parallelism and a lower proteoglycan content in Cartilage than more constant weight-bearing. Therefore, we hypothesize that the formation of mature Articular Cartilage with a highly parallel collagen network and relatively low proteoglycan content in the peak-loaded area of a joint is needed to withstand intermittent stress and shear, whereas a constantly weight-bearing joint area benefits from lower collagen parallelism and a higher proteoglycan content.
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effect of loading on the organization of the collagen fibril network in juvenile Equine Articular Cartilage
Journal of Orthopaedic Research, 2009Co-Authors: P A J Brama, Heikki J Helminen, Jaakko Holopainen, Rene P Van Weeren, E C Firth, Mika M HyttinenAbstract:We investigated the effects of exercise-induced loading on the collagen network of Equine Articular Cartilage. Collagen fibril architecture at a site (1) subjected to intermittent high-intensity loading was compared with that of an adjacent site (2) sustaining continuous low-level load. From horses exposed to forced exercise (CONDEX group) or not (PASTEX group), the spatial parallelism of fibrils and the orientation angle between fibrils and the surface at depths 9 µm apart through Cartilage from surface to tidemark were determined using polarized light microscopy, and expressed as parallelism index (PI) and orientation index (OI). PI was significantly higher in site 2 than 1 in CONDEX and PASTEX groups. PI was significantly higher in forced exercised horses at site 2 but not site 1. OI was significantly greater (more perpendicular to the surface) in the superficial and deep Cartilage of site 2 than 1 in both CONDEX and PASTEX groups. Superficial zone OI was higher in exercised horses at site 1 but not at site 2. Exercise increased collagen parallelism and affected orientation. The site differences in OI indicate that Benninghoff's classic predominantly perpendicular arcades appear not to be a consistent architectural feature, but adapt to local forces sustained. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
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effect of loading on the organization of the collagen fibril network in juvenile Equine Articular Cartilage
Journal of Orthopaedic Research, 2009Co-Authors: P A J Brama, Heikki J Helminen, Jaakko Holopainen, Rene P Van Weeren, E C Firth, Mika M HyttinenAbstract:We investigated the effects of exercise-induced loading on the collagen network of Equine Articular Cartilage. Collagen fibril architecture at a site (1) subjected to intermittent high-intensity loading was compared with that of an adjacent site (2) sustaining continuous low-level load. From horses exposed to forced exercise (CONDEX group) or not (PASTEX group), the spatial parallelism of fibrils and the orientation angle between fibrils and the surface at depths 9 microm apart through Cartilage from surface to tidemark were determined using polarized light microscopy, and expressed as parallelism index (PI) and orientation index (OI). PI was significantly higher in site 2 than 1 in CONDEX and PASTEX groups. PI was significantly higher in forced exercised horses at site 2 but not site 1. OI was significantly greater (more perpendicular to the surface) in the superficial and deep Cartilage of site 2 than 1 in both CONDEX and PASTEX groups. Superficial zone OI was higher in exercised horses at site 1 but not at site 2. Exercise increased collagen parallelism and affected orientation. The site differences in OI indicate that Benninghoff's classic predominantly perpendicular arcades appear not to be a consistent architectural feature, but adapt to local forces sustained.
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influence of exercise and joint topography on depth related spatial distribution of proteoglycan and collagen content in immature Equine Articular Cartilage
Equine Veterinary Journal, 2009Co-Authors: P A J Brama, Heikki J Helminen, Jaakko Holopainen, E C Firth, P. R. Weeren, Mika M HyttinenAbstract:Summary Reasons for performing study: There is ample evidence on topographical heterogeneity of the principal biochemical components of Articular Cartilage over the surface of the joint and the influence of loading thereon, but no information on depth-related zonal variation in horses. Objectives: To study depth-related zonal variation in proteoglycan (PG) and collagen content in Equine Articular Cartilage. Methods: Two techniques (safranin-O densitometry and Fourier transform infrared spectroscopy) were applied to sections of Articular Cartilage from the proximal phalangeal bone of the metacarpophalangeal joint of 18-month-old Thoroughbreds that had been raised at pasture from age 0–18 months without (PASTEX) and with (CONDEX) additional exercise. Two sites were investigated: site 1 at the joint margin that is unloaded at rest or at slow gaits, but subjected to high-intensity loading during athletic activity; and site 2, a continuously, but less intensively, loaded site in the centre of the joint. Results: Proteoglycan values increased from the surface to the deep layers of the Cartilage, collagen content showed a reverse pattern. PG content was significantly higher at site 2 in both PASTEX and CONDEX animals without an effect of exercise. In the PASTEX animals collagen content was significantly higher at site 1, but in the CONDEX group the situation was reversed, due to a significant exercise effect on site 1, leading to a reduced collagen content. Conclusions: Collagen and PG content gradients agree with findings in other species. The observations on PG levels suggest that the exercise level was not strenuous. The collagen results in the PASTEX group confirmed earlier findings, the lower levels at site 1 in the CONDEX group being possibly due to an advancement of the physiological maturation process of collagen remodelling. Potential relevance: This study confirms earlier observations that even moderate variations in exercise level in early age may have significant effects on the collagen network of Articular Cartilage.
David D. Frisbie - One of the best experts on this subject based on the ideXlab platform.
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Adult Bone Marrow Stromal Cell-Based Tissue-Engineered Aggrecan Exhibits Ultrastructure and Nanomechanical Properties Superior to Native Cartilage
2016Co-Authors: -y. H. Lee, David D. Frisbie, Anna Plaas, Paul W Kopesky, John D Kisiday, Ph. D. B, Ph. D. C, Ph. D. DAbstract:Objective—To quantify the structural characteristics and nanomechanical properties of aggrecan produced by adult bone marrow stromal cells (BMSCs) in peptide hydrogel scaffolds and compare to aggrecan from adult Articular Cartilage. Design—Adult Equine BMSCs were encapsulated in 3D-peptide hydrogels and cultured for 21 days with TGF-β1 to induce chondrogenic differentiation. BMSC-aggrecan was extracted and compared with aggrecan from age-matched adult Equine Articular Cartilage. Single molecules of aggrecan were visualized by atomic force microcopy-based imaging and aggrecan nanomechanical stiffness was quantified by high resolution force microscopy. Population-averaged measures of aggrecan hydrodynamic size, core protein structures and CS sulfation compositions were determined by size-exclusion chromatography, Western analysis, and fluorescence-assisted carbohydrate electrophoresis (FACE). Results—BMSC-aggrecan was primarily full-length while Cartilage-aggrecan had many fragments. Single molecule measurements showed that core protein and GAG chains of BMSC-aggrecan were markedly longer than those of Cartilage-aggrecan. Comparing full-length aggrecan of both species, BMSC-aggrecan had longer GAG chains, while the core protein trace lengths were similar. FAC
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adult bone marrow stromal cell based tissue engineered aggrecan exhibits ultrastructure and nanomechanical properties superior to native Cartilage
Osteoarthritis and Cartilage, 2010Co-Authors: Hsuyi Lee, Alan J Grodzinsky, David D. Frisbie, Anna Plaas, Paul W Kopesky, John D Sandy, John D Kisiday, Christine OrtizAbstract:Summary Objective To quantify the structural characteristics and nanomechanical properties of aggrecan produced by adult bone marrow stromal cells (BMSCs) in peptide hydrogel scaffolds and compare to aggrecan from adult Articular Cartilage. Design Adult Equine BMSCs were encapsulated in 3D-peptide hydrogels and cultured for 21 days with TGF-β1 to induce chondrogenic differentiation. BMSC-aggrecan was extracted and compared with aggrecan from age-matched adult Equine Articular Cartilage. Single molecules of aggrecan were visualized by atomic force microcopy-based imaging and aggrecan nanomechanical stiffness was quantified by high resolution force microscopy. Population-averaged measures of aggrecan hydrodynamic size, core protein structures and CS sulfation compositions were determined by size-exclusion chromatography, Western analysis, and fluorescence-assisted carbohydrate electrophoresis (FACE). Results BMSC-aggrecan was primarily full-length while Cartilage-aggrecan had many fragments. Single molecule measurements showed that core protein and GAG chains of BMSC-aggrecan were markedly longer than those of Cartilage-aggrecan. Comparing full-length aggrecan of both species, BMSC-aggrecan had longer GAG chains, while the core protein trace lengths were similar. FACE analysis detected a ∼1:1 ratio of chondroitin-4-sulfate to chondroitin-6-sulfate in BMSC-GAG, a phenotype consistent with aggrecan from skeletally-immature Cartilage. The nanomechanical stiffness of BMSC-aggrecan was demonstrably greater than that of Cartilage-aggrecan at the same total sGAG (fixed charge) density. Conclusions The higher proportion of full-length monomers, longer GAG chains and greater stiffness of the BMSC-aggrecan makes it biomechanically superior to adult Cartilage-aggrecan. Aggrecan stiffness was not solely dependent on fixed charge density, but also on GAG molecular ultrastructure. These results support the use of adult BMSCs for cell-based Cartilage repair.
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Effects of dosage titration of methylprednisolone acetate and triamcinolone acetonide on interleukin-1-conditioned Equine Articular Cartilage explants in vitro.
Equine veterinary journal, 2010Co-Authors: Julie E. Dechant, David D. Frisbie, Gayle W. Trotter, Gary M Baxter, C. Wayne McilwraithAbstract:Summary Reasons for performing study: Osteoarthritis is a frequent sequela of joint disease, especially with severe injuries or if attempts at therapy are unsuccessful. Negative and positive effects of corticosteroid treatment of Articular Cartilage have been demonstrated by in vitro and in vivo studies. Objectives: To assess the metabolic effects of varying dosages of methylprednisolone acetate (MPA) and triamcinolone acetonide (TA) on interleukin-1α (IL-1) conditioned Equine Cartilage explants. Our hypothesis was that lower dosages of corticosteroids would be less detrimental to Cartilage metabolism than higher dosages. TA would be less detrimental to Cartilage metabolism than MPA. Methods: Treatment groups included Articular Cartilage explants with no IL-1 (control), IL-1 alone, and IL-1 plus 10, 5, 1 and 0.5 mg/ml MPA or 1.2, 0.6, 0.12 and 0.06 mg/ml TA. Explants were labelled with 35SO4 priorto the beginning and end of the experiment to assess glycosaminoglycan (GAG) degradation and synthesis, respectively. Total GAG content in media and explants and total Cartilage DNA were also analysed. Results: MPA and TA reduced GAG synthesis compared to control and IL-1 alone. The highest dosage of MPA (10 mg/ml) reduced GAG synthesis less than lower dosages of MPA and all dosages of TA Compared to IL-1 alone, all dosages of TA and lower dosages of MPA increased GAG degradation. MPA at 10 mg/ml reduced GAG degradation. Both MPA and TA increased media GAG content compared to control and IL-1 explants. Total Cartilage GAGs were unchanged with MPA, but reduced with TA, compared with IL-1 alone. Total Cartilage DNA was decreased with MPA and increased with TA compared to IL-1 and control explants. Conclusions: MPA and TA did not counteract the negative effects of IL-1 and did not maintain Cartilage metabolism at control levels. Lower dosages of MPA and TA were not less detrimental to Cartilage metabolism than higher dosages. TA did not appear to be less harmful than MPA on Cartilage metabolism. The results of this study differ from the findings of comparable in vivo studies. Potential relevance: The low numbers of horses used in this study limits extrapolation of these findings to the Equine population; however, this study also questions the clinical relevance of this in vitro model.
Christine Ortiz - One of the best experts on this subject based on the ideXlab platform.
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adult bone marrow stromal cell based tissue engineered aggrecan exhibits ultrastructure and nanomechanical properties superior to native Cartilage
Osteoarthritis and Cartilage, 2010Co-Authors: Hsuyi Lee, Alan J Grodzinsky, David D. Frisbie, Anna Plaas, Paul W Kopesky, John D Sandy, John D Kisiday, Christine OrtizAbstract:Summary Objective To quantify the structural characteristics and nanomechanical properties of aggrecan produced by adult bone marrow stromal cells (BMSCs) in peptide hydrogel scaffolds and compare to aggrecan from adult Articular Cartilage. Design Adult Equine BMSCs were encapsulated in 3D-peptide hydrogels and cultured for 21 days with TGF-β1 to induce chondrogenic differentiation. BMSC-aggrecan was extracted and compared with aggrecan from age-matched adult Equine Articular Cartilage. Single molecules of aggrecan were visualized by atomic force microcopy-based imaging and aggrecan nanomechanical stiffness was quantified by high resolution force microscopy. Population-averaged measures of aggrecan hydrodynamic size, core protein structures and CS sulfation compositions were determined by size-exclusion chromatography, Western analysis, and fluorescence-assisted carbohydrate electrophoresis (FACE). Results BMSC-aggrecan was primarily full-length while Cartilage-aggrecan had many fragments. Single molecule measurements showed that core protein and GAG chains of BMSC-aggrecan were markedly longer than those of Cartilage-aggrecan. Comparing full-length aggrecan of both species, BMSC-aggrecan had longer GAG chains, while the core protein trace lengths were similar. FACE analysis detected a ∼1:1 ratio of chondroitin-4-sulfate to chondroitin-6-sulfate in BMSC-GAG, a phenotype consistent with aggrecan from skeletally-immature Cartilage. The nanomechanical stiffness of BMSC-aggrecan was demonstrably greater than that of Cartilage-aggrecan at the same total sGAG (fixed charge) density. Conclusions The higher proportion of full-length monomers, longer GAG chains and greater stiffness of the BMSC-aggrecan makes it biomechanically superior to adult Cartilage-aggrecan. Aggrecan stiffness was not solely dependent on fixed charge density, but also on GAG molecular ultrastructure. These results support the use of adult BMSCs for cell-based Cartilage repair.