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David L Butler - One of the best experts on this subject based on the ideXlab platform.
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effect of scaffold material construct length and Mechanical Stimulation on the in vitro stiffness of the engineered tendon construct
Journal of Biomechanics, 2008Co-Authors: Victor S Nirmalanandhan, Natalia Juncosamelvin, Jason T Shearn, Cindi Gooch, David L ButlerAbstract:Abstract Introducing mesenchymal stem cell (MSC)-seeded collagen constructs into load-protected wound sites in the rabbit patellar and Achilles tendons significantly improves their repair outcome compared to natural healing of the unfilled defect. However, these constructs would not be acceptable alternatives for repairing complete tendon ruptures because they lack the initial stiffness at the time of surgery to resist the expected peak in vivo forces thereafter. Since the stiffness of these constructs has also been shown to positively correlate with the stiffness of the subsequent repairs, improving initial stiffness by appropriate selection of in vitro culture conditions would seem crucial. In this study we examined the individual and combined effects of collagen scaffold type, construct length, and Mechanical Stimulation on in vitro implant stiffness. Two levels each of scaffold material (collagen gel vs. collagen sponge), construct length (short vs. long), and Mechanical Stimulation (stimulated vs. non-stimulated) were examined. Our results indicate that all three treatment factors influenced construct linear stiffness. Increasing the length of the construct had the greatest effect on the stiffness compared to introducing Mechanical Stimulation or changing the scaffold material. A significant interaction was also found between length and Stimulation. Of the eight groups studied, longer, stimulated, cell–sponge constructs showed the highest in vitro linear stiffness. We now plan in vivo studies to determine if higher stiffness constructs generate higher stiffness repairs 12 weeks after surgery and if in vitro construct stiffness continues to correlate with in vivo repair parameters like linear stiffness.
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Mechanical Stimulation of tendon tissue engineered constructs effects on construct stiffness repair biomechanics and their correlation
Journal of Biomechanical Engineering-transactions of The Asme, 2007Co-Authors: Jason T Shearn, Natalia Juncosamelvin, Gregory P Boivin, Marc T Galloway, Wendy Goodwin, Cynthia Gooch, Michael G Dunn, David L ButlerAbstract:: The objective of this study was to determine how in vitro Mechanical Stimulation of tissue engineered constructs affects their stiffness and modulus in culture and tendon repair biomechanics 12 weeks after surgical implantation. Using six female adult New Zealand White rabbits, autogenous tissue engineered constructs were created by seeding mesenchymal stem cells (0.1 x 10(6) cells/ml) in collagen gel (2.6 mg/ml) and combining both with a collagen sponge. Employing a novel experimental design strategy, four constructs from each animal were Mechanically stimulated (one 1 Hz cycle every 5 min to 2.4% peak strain for 8 h/day for 2 weeks) while the other four remained unstretched during the 2 week culture period. At the end of incubation, three of the Mechanically stimulated (S) and three of the nonstimulated (NS) constructs from each animal were assigned for in vitro Mechanical testing while the other two autogenous constructs were implanted into bilateral full-thickness, full-length defects created in the central third of rabbit patellar tendons (PTs). No significant differences were found in the in vitro linear stiffnesses between the S (0.15+/-0.1 N/mm) and NS constructs (0.08+/-0.02 N/mm; mean+/-SD). However, in vitro Mechanical Stimulation significantly increased the structural and material properties of the repair tissue, including a 14% increase in maximum force (p=0.01), a 50% increase in linear stiffness (p=0.001), and 23-41% increases in maximum stress and modulus (p=0.01). The S repairs achieved 65%, 80%, 60%, and 40% of normal central PT maximum force, linear stiffness, maximum stress, and linear modulus, respectively. The results for the S constructs exceed values obtained previously by our group using the same animal and defect model, and to our knowledge, this is the first study to show the benefits of in vitro Mechanical Stimulation on tendon repair biomechanics. In addition, the linear stiffnesses for the construct and repair were positively correlated (r=0.56) as were their linear moduli (r=0.68). Such in vitro predictors of in vivo outcome hold the potential to speed the development of tissue engineered products by reducing the time and costs of in vivo studies.
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Mechanical Stimulation increases collagen type i and collagen type iii gene expression of stem cell collagen sponge constructs for patellar tendon repair
Tissue Engineering, 2007Co-Authors: Natalia Juncosamelvin, Karl S Matlin, Robert W Holdcraft, Victor S Nirmalanandhan, David L ButlerAbstract:Our group has shown that Mechanical Stimulation increases the stiffness of stem cell-collagen sponge constructs at 14 days in culture and subsequent rabbit patellar tendon repairs at 12 weeks postsurgery. What remains unclear is which genes might be responsible for this increase in stiffness. Therefore, the objective of this study was to determine how a tensile stimulus affects the gene expression of stem cell-collagen sponge constructs used to repair rabbit central patellar tendon defects. Tissue-engineered constructs were created by seeding mesenchymal stem cells (MSCs) from 10 adult rabbits at 0.14 x 10(6) cells/construct in type I collagen sponges. Half of the constructs were Mechanically stimulated once every 5 min for 8 h/d to a peak strain of 2.4% for 2 weeks. The other half remained in an incubator without Mechanical Stimulation for 2 weeks. After 14 days in culture, half of the stimulated and nonstimulated constructs were prepared to determine the expression of collagen type I, collagen type III, decorin, fibronectin, and glyceraldehyde-3-phosphate dehydrogenase genes using real-time quantitative reverse transcriptase polymerase chain reaction. The remaining constructs were Mechanically tested to determine their Mechanical properties. Two weeks of in vitro Mechanical Stimulation significantly increased collagen type I and collagen type III gene expression of the stem cell-collagen sponge constructs. Stimulated constructs showed 3 and 4 times greater collagen type I (p = 0.0001) and collagen type III gene expression (p = 0.001) than nonstimulated controls. Stimulated constructs also had 2.5 times the linear stiffness and 4 times the linear modulus of nonstimulated constructs. However, Mechanical Stimulation did not significantly increase decorin or fibronectin gene expression (p = 0.2) after 14 days in culture. This study shows that Mechanical Stimulation of cell-sponge constructs produces similar increases in the expression of 2 structural genes, as well as linear stiffness and linear modulus.
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effects of Mechanical Stimulation on the biomechanics and histology of stem cell collagen sponge constructs for rabbit patellar tendon repair
Tissue Engineering, 2006Co-Authors: Natalia Juncosamelvin, Victor S Nirmalanandhan, Jason T Shearn, Gregory P Boivin, Marc T Galloway, Cynthia Gooch, John R West, Gino Bradica, David L ButlerAbstract:The objective of this study was to determine how Mechanical Stimulation affects the biomechanics and histology of stem cell-collagen sponge constructs used to repair central rabbit patellar tendon defects. Autogenous tissue-engineered constructs were created for both in vitro and in vivo analyses by seeding mesenchymal stem cells from 10 adult rabbits at 0.14x10(6) cells/construct in type I collagen sponges. Half of these constructs were Mechanically stimulated once every 5 min for 8 h/day to a peak strain of 4% for 2 weeks. The other half remained in an incubator without Mechanical Stimulation for 2 weeks. Samples allocated for in vitro testing revealed that Mechanically stimulated constructs had 2.5 times the linear stiffness of nonstimulated constructs. The remaining paired constructs for in vivo studies were implanted in bilateral full-thickness, full-length defects in the central third of rabbit patellar tendons. Twelve weeks after surgery, repair tissues were assigned for bioMechanical (7 pairs) and histologic (3 pairs) analyses. Maximum force, linear stiffness, maximum stress, and linear modulus for the stimulated (vs. nonstimulated) repairs averaged 70% (vs. 55%), 85% (vs. 55%), 70% (vs. 50%), and 50% (vs. 40%) of corresponding values for the normal central third of the patellar tendons. The average force-elongation curve for the Mechanically stimulated repairs also matched the corresponding curve for the normal patellar tendons, up to 150% of the peak in vivo force values recorded in a previous study. Construct and repair linear stiffness and linear modulus were also positively correlated (r = 0.6 and 0.7, respectively). Histologically both repairs showed excellent cellular alignment and mild staining for decorin and collagen type V, and moderate staining for fibronectin and collagen type III. This study shows that Mechanical Stimulation of stem cell-collagen sponge constructs can significantly improve tendon repair biomechanics up to and well beyond the functional limits of in vivo loading.
Natalia Juncosamelvin - One of the best experts on this subject based on the ideXlab platform.
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effect of scaffold material construct length and Mechanical Stimulation on the in vitro stiffness of the engineered tendon construct
Journal of Biomechanics, 2008Co-Authors: Victor S Nirmalanandhan, Natalia Juncosamelvin, Jason T Shearn, Cindi Gooch, David L ButlerAbstract:Abstract Introducing mesenchymal stem cell (MSC)-seeded collagen constructs into load-protected wound sites in the rabbit patellar and Achilles tendons significantly improves their repair outcome compared to natural healing of the unfilled defect. However, these constructs would not be acceptable alternatives for repairing complete tendon ruptures because they lack the initial stiffness at the time of surgery to resist the expected peak in vivo forces thereafter. Since the stiffness of these constructs has also been shown to positively correlate with the stiffness of the subsequent repairs, improving initial stiffness by appropriate selection of in vitro culture conditions would seem crucial. In this study we examined the individual and combined effects of collagen scaffold type, construct length, and Mechanical Stimulation on in vitro implant stiffness. Two levels each of scaffold material (collagen gel vs. collagen sponge), construct length (short vs. long), and Mechanical Stimulation (stimulated vs. non-stimulated) were examined. Our results indicate that all three treatment factors influenced construct linear stiffness. Increasing the length of the construct had the greatest effect on the stiffness compared to introducing Mechanical Stimulation or changing the scaffold material. A significant interaction was also found between length and Stimulation. Of the eight groups studied, longer, stimulated, cell–sponge constructs showed the highest in vitro linear stiffness. We now plan in vivo studies to determine if higher stiffness constructs generate higher stiffness repairs 12 weeks after surgery and if in vitro construct stiffness continues to correlate with in vivo repair parameters like linear stiffness.
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Mechanical Stimulation of tendon tissue engineered constructs effects on construct stiffness repair biomechanics and their correlation
Journal of Biomechanical Engineering-transactions of The Asme, 2007Co-Authors: Jason T Shearn, Natalia Juncosamelvin, Gregory P Boivin, Marc T Galloway, Wendy Goodwin, Cynthia Gooch, Michael G Dunn, David L ButlerAbstract:: The objective of this study was to determine how in vitro Mechanical Stimulation of tissue engineered constructs affects their stiffness and modulus in culture and tendon repair biomechanics 12 weeks after surgical implantation. Using six female adult New Zealand White rabbits, autogenous tissue engineered constructs were created by seeding mesenchymal stem cells (0.1 x 10(6) cells/ml) in collagen gel (2.6 mg/ml) and combining both with a collagen sponge. Employing a novel experimental design strategy, four constructs from each animal were Mechanically stimulated (one 1 Hz cycle every 5 min to 2.4% peak strain for 8 h/day for 2 weeks) while the other four remained unstretched during the 2 week culture period. At the end of incubation, three of the Mechanically stimulated (S) and three of the nonstimulated (NS) constructs from each animal were assigned for in vitro Mechanical testing while the other two autogenous constructs were implanted into bilateral full-thickness, full-length defects created in the central third of rabbit patellar tendons (PTs). No significant differences were found in the in vitro linear stiffnesses between the S (0.15+/-0.1 N/mm) and NS constructs (0.08+/-0.02 N/mm; mean+/-SD). However, in vitro Mechanical Stimulation significantly increased the structural and material properties of the repair tissue, including a 14% increase in maximum force (p=0.01), a 50% increase in linear stiffness (p=0.001), and 23-41% increases in maximum stress and modulus (p=0.01). The S repairs achieved 65%, 80%, 60%, and 40% of normal central PT maximum force, linear stiffness, maximum stress, and linear modulus, respectively. The results for the S constructs exceed values obtained previously by our group using the same animal and defect model, and to our knowledge, this is the first study to show the benefits of in vitro Mechanical Stimulation on tendon repair biomechanics. In addition, the linear stiffnesses for the construct and repair were positively correlated (r=0.56) as were their linear moduli (r=0.68). Such in vitro predictors of in vivo outcome hold the potential to speed the development of tissue engineered products by reducing the time and costs of in vivo studies.
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Mechanical Stimulation increases collagen type i and collagen type iii gene expression of stem cell collagen sponge constructs for patellar tendon repair
Tissue Engineering, 2007Co-Authors: Natalia Juncosamelvin, Karl S Matlin, Robert W Holdcraft, Victor S Nirmalanandhan, David L ButlerAbstract:Our group has shown that Mechanical Stimulation increases the stiffness of stem cell-collagen sponge constructs at 14 days in culture and subsequent rabbit patellar tendon repairs at 12 weeks postsurgery. What remains unclear is which genes might be responsible for this increase in stiffness. Therefore, the objective of this study was to determine how a tensile stimulus affects the gene expression of stem cell-collagen sponge constructs used to repair rabbit central patellar tendon defects. Tissue-engineered constructs were created by seeding mesenchymal stem cells (MSCs) from 10 adult rabbits at 0.14 x 10(6) cells/construct in type I collagen sponges. Half of the constructs were Mechanically stimulated once every 5 min for 8 h/d to a peak strain of 2.4% for 2 weeks. The other half remained in an incubator without Mechanical Stimulation for 2 weeks. After 14 days in culture, half of the stimulated and nonstimulated constructs were prepared to determine the expression of collagen type I, collagen type III, decorin, fibronectin, and glyceraldehyde-3-phosphate dehydrogenase genes using real-time quantitative reverse transcriptase polymerase chain reaction. The remaining constructs were Mechanically tested to determine their Mechanical properties. Two weeks of in vitro Mechanical Stimulation significantly increased collagen type I and collagen type III gene expression of the stem cell-collagen sponge constructs. Stimulated constructs showed 3 and 4 times greater collagen type I (p = 0.0001) and collagen type III gene expression (p = 0.001) than nonstimulated controls. Stimulated constructs also had 2.5 times the linear stiffness and 4 times the linear modulus of nonstimulated constructs. However, Mechanical Stimulation did not significantly increase decorin or fibronectin gene expression (p = 0.2) after 14 days in culture. This study shows that Mechanical Stimulation of cell-sponge constructs produces similar increases in the expression of 2 structural genes, as well as linear stiffness and linear modulus.
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effects of Mechanical Stimulation on the biomechanics and histology of stem cell collagen sponge constructs for rabbit patellar tendon repair
Tissue Engineering, 2006Co-Authors: Natalia Juncosamelvin, Victor S Nirmalanandhan, Jason T Shearn, Gregory P Boivin, Marc T Galloway, Cynthia Gooch, John R West, Gino Bradica, David L ButlerAbstract:The objective of this study was to determine how Mechanical Stimulation affects the biomechanics and histology of stem cell-collagen sponge constructs used to repair central rabbit patellar tendon defects. Autogenous tissue-engineered constructs were created for both in vitro and in vivo analyses by seeding mesenchymal stem cells from 10 adult rabbits at 0.14x10(6) cells/construct in type I collagen sponges. Half of these constructs were Mechanically stimulated once every 5 min for 8 h/day to a peak strain of 4% for 2 weeks. The other half remained in an incubator without Mechanical Stimulation for 2 weeks. Samples allocated for in vitro testing revealed that Mechanically stimulated constructs had 2.5 times the linear stiffness of nonstimulated constructs. The remaining paired constructs for in vivo studies were implanted in bilateral full-thickness, full-length defects in the central third of rabbit patellar tendons. Twelve weeks after surgery, repair tissues were assigned for bioMechanical (7 pairs) and histologic (3 pairs) analyses. Maximum force, linear stiffness, maximum stress, and linear modulus for the stimulated (vs. nonstimulated) repairs averaged 70% (vs. 55%), 85% (vs. 55%), 70% (vs. 50%), and 50% (vs. 40%) of corresponding values for the normal central third of the patellar tendons. The average force-elongation curve for the Mechanically stimulated repairs also matched the corresponding curve for the normal patellar tendons, up to 150% of the peak in vivo force values recorded in a previous study. Construct and repair linear stiffness and linear modulus were also positively correlated (r = 0.6 and 0.7, respectively). Histologically both repairs showed excellent cellular alignment and mild staining for decorin and collagen type V, and moderate staining for fibronectin and collagen type III. This study shows that Mechanical Stimulation of stem cell-collagen sponge constructs can significantly improve tendon repair biomechanics up to and well beyond the functional limits of in vivo loading.
Victor S Nirmalanandhan - One of the best experts on this subject based on the ideXlab platform.
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effect of scaffold material construct length and Mechanical Stimulation on the in vitro stiffness of the engineered tendon construct
Journal of Biomechanics, 2008Co-Authors: Victor S Nirmalanandhan, Natalia Juncosamelvin, Jason T Shearn, Cindi Gooch, David L ButlerAbstract:Abstract Introducing mesenchymal stem cell (MSC)-seeded collagen constructs into load-protected wound sites in the rabbit patellar and Achilles tendons significantly improves their repair outcome compared to natural healing of the unfilled defect. However, these constructs would not be acceptable alternatives for repairing complete tendon ruptures because they lack the initial stiffness at the time of surgery to resist the expected peak in vivo forces thereafter. Since the stiffness of these constructs has also been shown to positively correlate with the stiffness of the subsequent repairs, improving initial stiffness by appropriate selection of in vitro culture conditions would seem crucial. In this study we examined the individual and combined effects of collagen scaffold type, construct length, and Mechanical Stimulation on in vitro implant stiffness. Two levels each of scaffold material (collagen gel vs. collagen sponge), construct length (short vs. long), and Mechanical Stimulation (stimulated vs. non-stimulated) were examined. Our results indicate that all three treatment factors influenced construct linear stiffness. Increasing the length of the construct had the greatest effect on the stiffness compared to introducing Mechanical Stimulation or changing the scaffold material. A significant interaction was also found between length and Stimulation. Of the eight groups studied, longer, stimulated, cell–sponge constructs showed the highest in vitro linear stiffness. We now plan in vivo studies to determine if higher stiffness constructs generate higher stiffness repairs 12 weeks after surgery and if in vitro construct stiffness continues to correlate with in vivo repair parameters like linear stiffness.
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Mechanical Stimulation increases collagen type i and collagen type iii gene expression of stem cell collagen sponge constructs for patellar tendon repair
Tissue Engineering, 2007Co-Authors: Natalia Juncosamelvin, Karl S Matlin, Robert W Holdcraft, Victor S Nirmalanandhan, David L ButlerAbstract:Our group has shown that Mechanical Stimulation increases the stiffness of stem cell-collagen sponge constructs at 14 days in culture and subsequent rabbit patellar tendon repairs at 12 weeks postsurgery. What remains unclear is which genes might be responsible for this increase in stiffness. Therefore, the objective of this study was to determine how a tensile stimulus affects the gene expression of stem cell-collagen sponge constructs used to repair rabbit central patellar tendon defects. Tissue-engineered constructs were created by seeding mesenchymal stem cells (MSCs) from 10 adult rabbits at 0.14 x 10(6) cells/construct in type I collagen sponges. Half of the constructs were Mechanically stimulated once every 5 min for 8 h/d to a peak strain of 2.4% for 2 weeks. The other half remained in an incubator without Mechanical Stimulation for 2 weeks. After 14 days in culture, half of the stimulated and nonstimulated constructs were prepared to determine the expression of collagen type I, collagen type III, decorin, fibronectin, and glyceraldehyde-3-phosphate dehydrogenase genes using real-time quantitative reverse transcriptase polymerase chain reaction. The remaining constructs were Mechanically tested to determine their Mechanical properties. Two weeks of in vitro Mechanical Stimulation significantly increased collagen type I and collagen type III gene expression of the stem cell-collagen sponge constructs. Stimulated constructs showed 3 and 4 times greater collagen type I (p = 0.0001) and collagen type III gene expression (p = 0.001) than nonstimulated controls. Stimulated constructs also had 2.5 times the linear stiffness and 4 times the linear modulus of nonstimulated constructs. However, Mechanical Stimulation did not significantly increase decorin or fibronectin gene expression (p = 0.2) after 14 days in culture. This study shows that Mechanical Stimulation of cell-sponge constructs produces similar increases in the expression of 2 structural genes, as well as linear stiffness and linear modulus.
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effects of Mechanical Stimulation on the biomechanics and histology of stem cell collagen sponge constructs for rabbit patellar tendon repair
Tissue Engineering, 2006Co-Authors: Natalia Juncosamelvin, Victor S Nirmalanandhan, Jason T Shearn, Gregory P Boivin, Marc T Galloway, Cynthia Gooch, John R West, Gino Bradica, David L ButlerAbstract:The objective of this study was to determine how Mechanical Stimulation affects the biomechanics and histology of stem cell-collagen sponge constructs used to repair central rabbit patellar tendon defects. Autogenous tissue-engineered constructs were created for both in vitro and in vivo analyses by seeding mesenchymal stem cells from 10 adult rabbits at 0.14x10(6) cells/construct in type I collagen sponges. Half of these constructs were Mechanically stimulated once every 5 min for 8 h/day to a peak strain of 4% for 2 weeks. The other half remained in an incubator without Mechanical Stimulation for 2 weeks. Samples allocated for in vitro testing revealed that Mechanically stimulated constructs had 2.5 times the linear stiffness of nonstimulated constructs. The remaining paired constructs for in vivo studies were implanted in bilateral full-thickness, full-length defects in the central third of rabbit patellar tendons. Twelve weeks after surgery, repair tissues were assigned for bioMechanical (7 pairs) and histologic (3 pairs) analyses. Maximum force, linear stiffness, maximum stress, and linear modulus for the stimulated (vs. nonstimulated) repairs averaged 70% (vs. 55%), 85% (vs. 55%), 70% (vs. 50%), and 50% (vs. 40%) of corresponding values for the normal central third of the patellar tendons. The average force-elongation curve for the Mechanically stimulated repairs also matched the corresponding curve for the normal patellar tendons, up to 150% of the peak in vivo force values recorded in a previous study. Construct and repair linear stiffness and linear modulus were also positively correlated (r = 0.6 and 0.7, respectively). Histologically both repairs showed excellent cellular alignment and mild staining for decorin and collagen type V, and moderate staining for fibronectin and collagen type III. This study shows that Mechanical Stimulation of stem cell-collagen sponge constructs can significantly improve tendon repair biomechanics up to and well beyond the functional limits of in vivo loading.
Winghoi Cheung - One of the best experts on this subject based on the ideXlab platform.
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Mechanical Stimulation enhanced estrogen receptor expression and callus formation in diaphyseal long bone fracture healing in ovariectomy induced osteoporotic rats
Osteoporosis International, 2016Co-Authors: Simon Kwoonho Chow, Kwoksui Leung, Jianghui Qin, An Yun Guo, Minghui Sun, Ling Qin, Winghoi CheungAbstract:Summary Estrogen receptor (ER) in ovariectomy-induced osteoporotic fracture was reported to exhibit delayed expression. Mechanical Stimulation enhanced ER-α expression in osteoporotic fracture callus at the tissue level. ER was also found to be required for the effectiveness of vibrational Mechanical Stimulation treatment in osteoporotic fracture healing.
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Mechanical Stimulation enhanced estrogen receptor expression and callus formation in diaphyseal long bone fracture healing in ovariectomy induced osteoporotic rats
Osteoporosis International, 2016Co-Authors: Simon Kwoonho Chow, Kwoksui Leung, Jianghui Qin, An Yun Guo, Minghui Sun, Ling Qin, Winghoi CheungAbstract:Estrogen receptor (ER) in ovariectomy-induced osteoporotic fracture was reported to exhibit delayed expression. Mechanical Stimulation enhanced ER-α expression in osteoporotic fracture callus at the tissue level. ER was also found to be required for the effectiveness of vibrational Mechanical Stimulation treatment in osteoporotic fracture healing. Estrogen receptor(ER) is involved in Mechanical signal transduction in bone metabolism. Its expression was reported to be delayed in osteoporotic fracture healing. The purpose of this study was to investigate the roles played by ER during osteoporotic fracture healing enhanced with Mechanical Stimulation. Ovariectomy-induced osteoporotic SD rats that received closed femoral fractures were divided into five groups, (i) SHAM, (ii) SHAM-VT, (iii) OVX, (iv) OVX-VT, and (v) OVX-VT-ICI, where VT stands for whole-body vibration treatment and ICI for ER antagonization by ICI 182,780. Callus formation and gene expression were assessed at 2, 4, and 8 weeks postfracture. In vitro osteoblastic differentiation, mineralization, and ER-α expression were assessed. The delayed ER expression was found to be enhanced by vibration treatment. Callus formation enhancement was shown by callus morphometry and micro-CT analysis. Enhancement effects by vibration were partially abolished when ER was modulated by ICI 182,780, in terms of callus formation capacity at 2–4 weeks and ER gene and protein expression at all time points. In vitro, ER expression in osteoblasts was not enhanced by VT treatment, but osteoblastic differentiation and mineralization were enhanced under estrogen-deprived condition. When osteoblastic cells were modulated by ICI 182,780, enhancement effects of VT were eliminated. Vibration was able to enhance ER expression in ovariectomy-induced osteoporotic fracture healing. ER was essential in Mechanical signal transduction and enhancement in callus formation effects during osteoporotic fracture healing enhanced by vibration. The enhancement of ER-α expression by Mechanical Stimulation was not likely to be related to the increased expression in osteoblastic cells but rather to the systemic enhancement in recruitment of ER-expressing progenitor cells through increased blood flow and neo-angiogenesis. This finding might explain the observed difference in Mechanical sensitivity of osteoporotic fracture to Mechanical Stimulation.
Kwoksui Leung - One of the best experts on this subject based on the ideXlab platform.
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Mechanical Stimulation enhanced estrogen receptor expression and callus formation in diaphyseal long bone fracture healing in ovariectomy induced osteoporotic rats
Osteoporosis International, 2016Co-Authors: Simon Kwoonho Chow, Kwoksui Leung, Jianghui Qin, An Yun Guo, Minghui Sun, Ling Qin, Winghoi CheungAbstract:Summary Estrogen receptor (ER) in ovariectomy-induced osteoporotic fracture was reported to exhibit delayed expression. Mechanical Stimulation enhanced ER-α expression in osteoporotic fracture callus at the tissue level. ER was also found to be required for the effectiveness of vibrational Mechanical Stimulation treatment in osteoporotic fracture healing.
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Mechanical Stimulation enhanced estrogen receptor expression and callus formation in diaphyseal long bone fracture healing in ovariectomy induced osteoporotic rats
Osteoporosis International, 2016Co-Authors: Simon Kwoonho Chow, Kwoksui Leung, Jianghui Qin, An Yun Guo, Minghui Sun, Ling Qin, Winghoi CheungAbstract:Estrogen receptor (ER) in ovariectomy-induced osteoporotic fracture was reported to exhibit delayed expression. Mechanical Stimulation enhanced ER-α expression in osteoporotic fracture callus at the tissue level. ER was also found to be required for the effectiveness of vibrational Mechanical Stimulation treatment in osteoporotic fracture healing. Estrogen receptor(ER) is involved in Mechanical signal transduction in bone metabolism. Its expression was reported to be delayed in osteoporotic fracture healing. The purpose of this study was to investigate the roles played by ER during osteoporotic fracture healing enhanced with Mechanical Stimulation. Ovariectomy-induced osteoporotic SD rats that received closed femoral fractures were divided into five groups, (i) SHAM, (ii) SHAM-VT, (iii) OVX, (iv) OVX-VT, and (v) OVX-VT-ICI, where VT stands for whole-body vibration treatment and ICI for ER antagonization by ICI 182,780. Callus formation and gene expression were assessed at 2, 4, and 8 weeks postfracture. In vitro osteoblastic differentiation, mineralization, and ER-α expression were assessed. The delayed ER expression was found to be enhanced by vibration treatment. Callus formation enhancement was shown by callus morphometry and micro-CT analysis. Enhancement effects by vibration were partially abolished when ER was modulated by ICI 182,780, in terms of callus formation capacity at 2–4 weeks and ER gene and protein expression at all time points. In vitro, ER expression in osteoblasts was not enhanced by VT treatment, but osteoblastic differentiation and mineralization were enhanced under estrogen-deprived condition. When osteoblastic cells were modulated by ICI 182,780, enhancement effects of VT were eliminated. Vibration was able to enhance ER expression in ovariectomy-induced osteoporotic fracture healing. ER was essential in Mechanical signal transduction and enhancement in callus formation effects during osteoporotic fracture healing enhanced by vibration. The enhancement of ER-α expression by Mechanical Stimulation was not likely to be related to the increased expression in osteoblastic cells but rather to the systemic enhancement in recruitment of ER-expressing progenitor cells through increased blood flow and neo-angiogenesis. This finding might explain the observed difference in Mechanical sensitivity of osteoporotic fracture to Mechanical Stimulation.