The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Koichi Omori - One of the best experts on this subject based on the ideXlab platform.
-
bioengineered trachea using autologous chondrocytes for regeneration of Tracheal Cartilage in a rabbit model
Laryngoscope, 2013Co-Authors: Mika Nomoto, Tatsuo Nakamura, Yukio Nomoto, Yasuhiro Tada, Akiko Tani, Koshi Otsuki, Ryo Suzuki, Koichi OmoriAbstract:Objectives/Hypothesis In this study, a bioengineered trachea composed of autologous chondrocytes was developed, and its effect on cartilaginous regeneration was evaluated by implantation into Tracheal defects in rabbits. Study Design Prospective controlled trial in an animal model. Methods The Tracheal prosthesis used in this study was composed of polypropylene (the frame) and collagen sponge (the scaffold). Chondrocytes were harvested from the costal Cartilage of rabbits and seeded into the Tracheal prosthesis. The bioengineered trachea, consisting of the Tracheal prosthesis with chondrocytes, was implanted into surgically created Tracheal defects of rabbits in the bioengineered group, and a Tracheal prosthesis without chondrocytes was implanted in the control group. Results After implantation, the presence of regenerated Cartilage was observed in the bioengineered trachea but not in the Tracheal prosthesis without chondrocytes. Conclusions It was confirmed in this study that the implanted chondrocytes proliferated in an appropriate portion of the Tracheal defect and that the partially resected Tracheal Cartilage was repaired with regenerated cartilaginous tissue into a ring-shaped form as a whole. These results demonstrate the feasibility of cartilaginous regeneration using a bioengineered trachea with autologous chondrocytes Laryngoscope, 123:2195–2201, 2013 Level of Evidence NA
-
evaluation of the use of induced pluripotent stem cells ipscs for the regeneration of Tracheal Cartilage
Cell Transplantation, 2013Co-Authors: Mitsuyoshi Imaizumi, Tatsuo Nakamura, Yukio Nomoto, Yuka Sato, Takashi Sugino, Masao Miyake, Ikuo Wada, Koichi OmoriAbstract:The treatment of laryngoTracheal stenosis remains a challenge as treatment often requires multistaged procedures, and successful decannulation sometimes fails after a series of operations. Induced ...
-
a tissue engineering approach for stenosis of the trachea and or cricoid
Acta Oto-laryngologica, 2010Co-Authors: Shinichi Kanemaru, Tatsuo Nakamura, Shigeru Hirano, Koichi Omori, Hiroo Umeda, Masaru Yamashita, Atsushi Suehiro, Toshiki Maetani, Juichi ItoAbstract:AbstractConclusion: This new regenerative therapy shows great potential for the treatment of stenosis of the trachea and/or cricoids (STC). Objectives: To estimate the potential of tissue-engineered artificial trachea (AT) for treatment of STC in clinical applications. We previously reported that AT was a useful material for implantation into a Tracheal defect after resection of cancer. There are many causes of stenosis of the respiratory tract and STC is particularly difficult to treat. Methods: The AT was a spiral stent composed of Marlex mesh made of polypropylene and covered with collagen sponge made from porcine skin. Three patients with STC were treated by this tissue-engineering method. All of them suffered from STC caused by long endoTracheal intubations. They underwent a two-stage operation. In the first operation, after resection of the stenotic regions, the edge of the Tracheal Cartilage was sutured to the edge of the skin. The Tracheal lumen was exposed and a T-shaped cannula was inserted into...
-
cricoid regeneration using in situ tissue engineering in canine larynx for the treatment of subglottic stenosis
Annals of Otology Rhinology and Laryngology, 2004Co-Authors: Koichi Omori, Tatsuo Nakamura, Hisayoshi Kojima, Shinichi Kanemaru, Akhmar Magrufov, Yasuyuki Hiratsuka, Yasuhiko ShimizuAbstract:The purpose of the present study was to evaluate the efficacy of cricoid regeneration via in situ tissue engineering in a canine larynx for the treatment of subglottic stenosis. As the tissue scaffold, a Marlex mesh tube coated by collagen sponge was used for a rigid airway framework and for tissue regrowth around the tube. On 5 dogs, the larynx was exposed and the anterior third of the cricoid Cartilage was resected. The tube was anastomosed to the lower edge of the thyroid Cartilage and to the first Tracheal Cartilage. By postoperative endoscopic examination at 3 to 7 months, no airway obstruction was observed in any of the dogs. There was granulation tissue in 2 dogs and slight mesh exposure in 1 dog, but they were asymptomatic. Confluent regeneration of the epithelium over the scaffold and good incorporation of the scaffold mesh into the host tissue were observed after surgery.
-
Vibratory analysis of the neoglottis after surgical intervention of cricopharyngeal myotomy and implantation of Tracheal Cartilage.
Archives of otolaryngology--head & neck surgery, 1999Co-Authors: Shigeru Hirano, Hisayoshi Kojima, Kazuhiko Shoji, Ken Ichi Kaneko, Ichiro Tateya, Ryo Asato, Koichi OmoriAbstract:Objective To examine the effect of a new surgical intervention, consisting of cricopharyngeal myotomy and Tracheal cartilaginous implantation on the anterior wall of the esophagus, for tracheoesophageal shunt and esophageal phonation. Design We examined the vibration of the neoglottis of tracheoesophageal shunt and esophageal speakers after total laryngectomy using a high-speed video camera (frame rate, 1000 per second). Patients Twenty-one alaryngeal patients were involved: 13 who had undergone the present procedure and 8 who had not. Results The regularity of neoglottal vibration and the degree of neoglottal closure were significantly (P Conclusions Cricopharyngeal myotomy was useful for avoiding reconstructed esophageal spasm, and Tracheal cartilaginous implantation was effective for maintaining a wide subneoglottal space. This combination of procedures is useful for obtaining optimal vibration of the neoglottis in tracheoesophageal shunt and esophageal speakers.
Debora Sinner - One of the best experts on this subject based on the ideXlab platform.
-
notum attenuates wnt β catenin signaling to promote Tracheal Cartilage patterning
Developmental Biology, 2018Co-Authors: Bradley Gerhardt, John Snowball, Manoj Ambalavanan, Lauren Leesman, Kaulini Burra, Rachel Rosenzweig, Natalie Guzman, Debora SinnerAbstract:Tracheobronchomalacia (TBM) is a common congenital disorder in which the cartilaginous rings of the trachea are weakened or missing. Despite the high prevalence and clinical issues associated with TBM, the etiology is largely unknown. Our previous studies demonstrated that Wntless (Wls) and its associated Wnt pathways are critical for patterning of the upper airways. Deletion of Wls in respiratory endoderm caused TBM and ectopic Trachealis muscle. To understand mechanisms by which Wls mediates Tracheal patterning, we performed RNA sequencing in prechondrogenic Tracheal tissue of Wlsf/f;ShhCre/wt embryos. Chondrogenic Bmp4, and Sox9 were decreased, while expression of myogenic genes was increased. We identified Notum, a deacylase that inactivates Wnt ligands, as a target of Wls induced Wnt signaling. Notum's mesenchymal ventral expression in prechondrogenic trachea overlaps with expression of Axin2, a Wnt/β-catenin target and inhibitor. Notum is induced by Wnt/β-catenin in developing trachea. Deletion of Notum activated mesenchymal Wnt/β-catenin and caused Tracheal mispatterning of Trachealis muscle and Cartilage as well as Tracheal stenosis. Notum is required for Tracheal morphogenesis, influencing mesenchymal condensations critical for patterning of Tracheal Cartilage and muscle. We propose that Notum influences mesenchymal cell differentiation by generating a barrier for Wnt ligands produced and secreted by airway epithelial cells to attenuate Wnt signaling.
-
endodermal wnt signaling is required for Tracheal Cartilage formation
Developmental Biology, 2015Co-Authors: John Snowball, Manoj Ambalavanan, Jeffrey A Whitsett, Debora SinnerAbstract:Tracheobronchomalacia is a common congenital defect in which the walls of the trachea and bronchi lack of adequate Cartilage required for support of the airways. Deletion of Wls, a cargo receptor mediating Wnt ligand secretion, in the embryonic endoderm using ShhCre mice inhibited formation of Tracheal-bronchial cartilaginous rings. The normal dorsal-ventral patterning of Tracheal mesenchyme was lost. Smooth muscle cells, identified by Acta2 staining, were aberrantly located in ventral mesenchyme of the trachea, normally the region of Sox9 expression in Cartilage progenitors. Wnt/β-catenin activity, indicated by Axin2 LacZ reporter, was decreased in Tracheal mesenchyme of Wls(f/f);Shh(Cre/+) embryos. Proliferation of chondroblasts was decreased and reciprocally, proliferation of smooth muscle cells was increased in Wls(f/f);Shh(Cre/+) Tracheal tissue. Expression of Tbx4, Tbx5, Msx1 and Msx2, known to mediate Cartilage and muscle patterning, were decreased in Tracheal mesenchyme of Wls(f/f);Shh(Cre/+) embryos. Ex vivo studies demonstrated that Wnt7b and Wnt5a, expressed by the epithelium of developing trachea, and active Wnt/β-catenin signaling are required for Tracheal chondrogenesis before formation of mesenchymal condensations. In conclusion, Wnt ligands produced by the Tracheal epithelium pattern the Tracheal mesenchyme via modulation of gene expression and cell proliferation required for proper Tracheal Cartilage and smooth muscle differentiation.
Hiroyasu Yokomise - One of the best experts on this subject based on the ideXlab platform.
-
widespread and early Tracheal Cartilage regeneration by synchronous slow release of b fgf and bmp 2
Asaio Journal, 2009Co-Authors: Hitoshi Igai, Sung Soo Chang, Masashi Gotoh, Yasumichi Yamamoto, Masaya Yamamoto, Yasuhiko Tabata, Hiroyasu YokomiseAbstract:Our previous studies have demonstrated that slow release of basic fibroblast growth factor (b-FGF) or bone morphogenetic protein 2 (BMP-2) induces Cartilage regeneration. In the present study, we investigated whether synchronous slow release of b-FGF and BMP-2 would induce more widespread and earlie
-
Tracheal Cartilage regeneration and new bone formation by slow release of bone morphogenetic protein bmp 2
Asaio Journal, 2008Co-Authors: Hitoshi Igai, Sung Soo Chang, Masashi Gotoh, Yasumichi Yamamoto, Masaya Yamamoto, Yasuhiko Tabata, Hiroyasu YokomiseAbstract:We investigated the efficiency of bone morphogenetic protein (BMP)-2 released slowly from gelatin sponge for Tracheal Cartilage regeneration. A 1-cm gap was made in the mid-ventral portion of each of 10 consecutive Tracheal Cartilages. In the control group (n = 4), the resulting gap was left untreated. In the gelatin group (n = 4), plain gelatin was implanted in the gap. In the BMP-2 group (n = 4), gelatin containing 100 microg BMP-2 was implanted. We euthanatized all dogs in each group at 1, 3, 6, and 12 months after the implantation, respectively, and then examined the implant site macro- and microscopically. In the BMP-2 group, regenerated fibrous Cartilage and newly formed bone were observed at 1 and 12 months. Regenerated Cartilage was observed at the ends of the host Cartilage stumps, with newly formed bone in the middle portion. The gaps were filled with regenerated Cartilage and newly formed bone. At 3 and 6 months, regenerated Cartilage, but not newly formed bone, was evident. The regenerated Cartilage was covered with perichondrium and showed continuity with the host Cartilage. We succeeded in inducing Cartilage regeneration and new bone formation in canine trachea by slow release of 100 microg BMP-2 from gelatin.
-
Tracheal Cartilage regeneration by slow release of basic fibroblast growth factor from a gelatin sponge
The Journal of Thoracic and Cardiovascular Surgery, 2007Co-Authors: Hitoshi Igai, Sung Soo Chang, Yasumichi Yamamoto, Masaya Yamamoto, Yasuhiko Tabata, Hiroyasu YokomiseAbstract:Objective We investigated whether implantation of a gelatin sponge, releasing basic fibroblast growth factor slowly (b-FGF) into a Tracheal Cartilage defect, would induce regeneration of autologous Tracheal Cartilage. Methods We created a 1-cm defect in the midventral portion of each of 10 consecutive cervical Tracheal Cartilage rings in 12 experimental dogs. In the control group (n = 4), the resulting defects were left untreated. In the gelatin group (n = 4), empty gelatin sponges were implanted in the defects. In the basic fibroblast growth factor group (n = 4), gelatin sponges incorporating 100 μg of b-FGF solution were implanted in the defects. We killed the 4 dogs in each group at 1, 3, 6, and 12 months after implantation, respectively, and examined the implant sites macro- and microscopically. Results In the control and gelatin groups, no regenerated Cartilage was observed in the Tracheal Cartilage defects, and the width of the gap between the host Cartilage stumps had shrunk. In the b-FGF group, regenerated Cartilage was observed in all dogs. The proportion of the defect in the host Cartilage occupied by regenerated Cartilage was 13%, 84%, 75%, and 69% at 1, 3, 6, and 12 months, respectively. The regenerated Cartilage was fibrous Cartilage covered with perichondrium, which grew from the host perichondrium and showed continuity with the host Cartilage stumps. Conclusions Implantation of a gelatin sponge slowly releasing basic fibroblast growth factor induces Tracheal Cartilage regeneration, which subsequently fills a large proportion of experimentally created Tracheal Cartilage defects within 12 months after implantation.
-
regeneration of canine Tracheal Cartilage by slow release of basic fibroblast growth factor from gelatin sponge
Asaio Journal, 2006Co-Authors: Hitoshi Igai, Taku Okamoto, Sung Soo Chang, Noriyuki Misaki, Masashi Gotoh, Yasumichi Yamamoto, Masaya Yamamoto, Yasuhiko Tabata, Hiroyasu YokomiseAbstract:: We investigated the efficiency of basic fibroblast growth factor (b-FGF) released from a gelatin sponge in the regeneration of Tracheal Cartilage. A 1-cm gap was made in the midventral portion of each of 10 consecutive cervical Tracheal Cartilages (rings 4 to 13) in 15 experimental dogs. In the control group (n = 5), the resulting gap was left blank. In the gelatin group (n = 5), a gelatin sponge alone was implanted in the gap. In the b-FGF group (n = 5), a gelatin sponge containing 100 mug b-FGF solution was implanted in the gap. We euthanatized one of the five dogs in each group at 1 month after implantation and one at 3 months and examined the implant sites macroscopically and microscopically. In the control and gelatin groups, no regenerated Cartilage was observed in the Tracheal Cartilage gap at 1 or 3 months. The distances between the Cartilage stumps had shrunk. In the b-FGF group, fibrous Cartilage had started to regenerate from both host Cartilage stumps at 1 month. At 3 months, regenerated fibrous Cartilage filled the gap and had connected each of the stumps. The regenerated Cartilage was covered with regenerated perichondrium originating from the host perichondrium. Shrinkage of the distance between the host Cartilage stumps was not observed in the b-FGF group. We succeeded in inducing Cartilage regeneration in the gaps in canine Tracheal Cartilage rings by using the slow release of b-FGF from a gelatin sponge. The regenerated Cartilage induced by b-FGF was fibrous Cartilage.
-
slow release of bone morphogenetic protein 2 from a gelatin sponge to promote regeneration of Tracheal Cartilage in a canine model
The Journal of Thoracic and Cardiovascular Surgery, 2004Co-Authors: Taku Okamoto, Masashi Gotoh, Yasumichi Yamamoto, Chenglong Huang, Tatsuo Nakamura, Yasuhiko Shimizu, Yasuhiko Tabata, Hiroyasu YokomiseAbstract:Abstract Objectives We investigated whether bone morphogenetic protein 2, released slowly from a gelatin sponge, could induce Cartilage regeneration in a canine model of tracheomalacia and evaluated the long-term results. Methods A 1 × 5-cm gap was made in the anterior cervical trachea by removing 5-cm long strips of 10 sequential cartilagines. In the control group (n = 5), the gaps were left untreated. In the gelatin sponge group (n = 5), a gelatin sponge soaked in a buffer solution was implanted in each defect. In the bone morphogenetic protein group (n = 5), a gelatin sponge soaked in a buffer solution containing 12 μg bone morphogenetic protein 2 was implanted in each defect. Results Tracheomalacia was observed in the control and gelatin sponge groups but not in the bone morphogenetic protein group. No regenerated Cartilage was detected in the control or gelatin sponge groups, even 6 months after surgery. In contrast, regenerated Cartilage, which had developed from the host perichondrium, was observed around the stumps of the resected cartilagines in the bone morphogenetic protein group. This regenerated Cartilage maintained the integrity of the internal lumen for longer than 6 months. A compressive fracture test revealed that the Tracheal Cartilage in the bone morphogenetic protein group was significantly more stable than that in the gelatin sponge and control groups ( P = .0015 and P = .0001, respectively). Conclusions In this canine model of tracheomalacia, Cartilage regeneration was induced around the stumps of Tracheal cartilagines by bone morphogenetic protein 2 released slowly from a gelatin sponge. This regenerated Cartilage was not reabsorbed for longer than 6 months and was strong enough to maintain the integrity of the internal lumen of the trachea.
Tatsuo Nakamura - One of the best experts on this subject based on the ideXlab platform.
-
bioengineered trachea using autologous chondrocytes for regeneration of Tracheal Cartilage in a rabbit model
Laryngoscope, 2013Co-Authors: Mika Nomoto, Tatsuo Nakamura, Yukio Nomoto, Yasuhiro Tada, Akiko Tani, Koshi Otsuki, Ryo Suzuki, Koichi OmoriAbstract:Objectives/Hypothesis In this study, a bioengineered trachea composed of autologous chondrocytes was developed, and its effect on cartilaginous regeneration was evaluated by implantation into Tracheal defects in rabbits. Study Design Prospective controlled trial in an animal model. Methods The Tracheal prosthesis used in this study was composed of polypropylene (the frame) and collagen sponge (the scaffold). Chondrocytes were harvested from the costal Cartilage of rabbits and seeded into the Tracheal prosthesis. The bioengineered trachea, consisting of the Tracheal prosthesis with chondrocytes, was implanted into surgically created Tracheal defects of rabbits in the bioengineered group, and a Tracheal prosthesis without chondrocytes was implanted in the control group. Results After implantation, the presence of regenerated Cartilage was observed in the bioengineered trachea but not in the Tracheal prosthesis without chondrocytes. Conclusions It was confirmed in this study that the implanted chondrocytes proliferated in an appropriate portion of the Tracheal defect and that the partially resected Tracheal Cartilage was repaired with regenerated cartilaginous tissue into a ring-shaped form as a whole. These results demonstrate the feasibility of cartilaginous regeneration using a bioengineered trachea with autologous chondrocytes Laryngoscope, 123:2195–2201, 2013 Level of Evidence NA
-
evaluation of the use of induced pluripotent stem cells ipscs for the regeneration of Tracheal Cartilage
Cell Transplantation, 2013Co-Authors: Mitsuyoshi Imaizumi, Tatsuo Nakamura, Yukio Nomoto, Yuka Sato, Takashi Sugino, Masao Miyake, Ikuo Wada, Koichi OmoriAbstract:The treatment of laryngoTracheal stenosis remains a challenge as treatment often requires multistaged procedures, and successful decannulation sometimes fails after a series of operations. Induced ...
-
a tissue engineering approach for stenosis of the trachea and or cricoid
Acta Oto-laryngologica, 2010Co-Authors: Shinichi Kanemaru, Tatsuo Nakamura, Shigeru Hirano, Koichi Omori, Hiroo Umeda, Masaru Yamashita, Atsushi Suehiro, Toshiki Maetani, Juichi ItoAbstract:AbstractConclusion: This new regenerative therapy shows great potential for the treatment of stenosis of the trachea and/or cricoids (STC). Objectives: To estimate the potential of tissue-engineered artificial trachea (AT) for treatment of STC in clinical applications. We previously reported that AT was a useful material for implantation into a Tracheal defect after resection of cancer. There are many causes of stenosis of the respiratory tract and STC is particularly difficult to treat. Methods: The AT was a spiral stent composed of Marlex mesh made of polypropylene and covered with collagen sponge made from porcine skin. Three patients with STC were treated by this tissue-engineering method. All of them suffered from STC caused by long endoTracheal intubations. They underwent a two-stage operation. In the first operation, after resection of the stenotic regions, the edge of the Tracheal Cartilage was sutured to the edge of the skin. The Tracheal lumen was exposed and a T-shaped cannula was inserted into...
-
cricoid regeneration using in situ tissue engineering in canine larynx for the treatment of subglottic stenosis
Annals of Otology Rhinology and Laryngology, 2004Co-Authors: Koichi Omori, Tatsuo Nakamura, Hisayoshi Kojima, Shinichi Kanemaru, Akhmar Magrufov, Yasuyuki Hiratsuka, Yasuhiko ShimizuAbstract:The purpose of the present study was to evaluate the efficacy of cricoid regeneration via in situ tissue engineering in a canine larynx for the treatment of subglottic stenosis. As the tissue scaffold, a Marlex mesh tube coated by collagen sponge was used for a rigid airway framework and for tissue regrowth around the tube. On 5 dogs, the larynx was exposed and the anterior third of the cricoid Cartilage was resected. The tube was anastomosed to the lower edge of the thyroid Cartilage and to the first Tracheal Cartilage. By postoperative endoscopic examination at 3 to 7 months, no airway obstruction was observed in any of the dogs. There was granulation tissue in 2 dogs and slight mesh exposure in 1 dog, but they were asymptomatic. Confluent regeneration of the epithelium over the scaffold and good incorporation of the scaffold mesh into the host tissue were observed after surgery.
-
slow release of bone morphogenetic protein 2 from a gelatin sponge to promote regeneration of Tracheal Cartilage in a canine model
The Journal of Thoracic and Cardiovascular Surgery, 2004Co-Authors: Taku Okamoto, Masashi Gotoh, Yasumichi Yamamoto, Chenglong Huang, Tatsuo Nakamura, Yasuhiko Shimizu, Yasuhiko Tabata, Hiroyasu YokomiseAbstract:Abstract Objectives We investigated whether bone morphogenetic protein 2, released slowly from a gelatin sponge, could induce Cartilage regeneration in a canine model of tracheomalacia and evaluated the long-term results. Methods A 1 × 5-cm gap was made in the anterior cervical trachea by removing 5-cm long strips of 10 sequential cartilagines. In the control group (n = 5), the gaps were left untreated. In the gelatin sponge group (n = 5), a gelatin sponge soaked in a buffer solution was implanted in each defect. In the bone morphogenetic protein group (n = 5), a gelatin sponge soaked in a buffer solution containing 12 μg bone morphogenetic protein 2 was implanted in each defect. Results Tracheomalacia was observed in the control and gelatin sponge groups but not in the bone morphogenetic protein group. No regenerated Cartilage was detected in the control or gelatin sponge groups, even 6 months after surgery. In contrast, regenerated Cartilage, which had developed from the host perichondrium, was observed around the stumps of the resected cartilagines in the bone morphogenetic protein group. This regenerated Cartilage maintained the integrity of the internal lumen for longer than 6 months. A compressive fracture test revealed that the Tracheal Cartilage in the bone morphogenetic protein group was significantly more stable than that in the gelatin sponge and control groups ( P = .0015 and P = .0001, respectively). Conclusions In this canine model of tracheomalacia, Cartilage regeneration was induced around the stumps of Tracheal cartilagines by bone morphogenetic protein 2 released slowly from a gelatin sponge. This regenerated Cartilage was not reabsorbed for longer than 6 months and was strong enough to maintain the integrity of the internal lumen of the trachea.
Peter D Pare - One of the best experts on this subject based on the ideXlab platform.
-
ultrastructure and tensile properties of human Tracheal Cartilage
Journal of Biomechanics, 1997Co-Authors: Clive R Roberts, Jeffrey K Rains, Peter D Pare, David C Walker, Barry Wiggs, J L BertAbstract:Abstract The Cartilage of the walls of the trachea and bronchi acts to keep these airways open despite intrathoracic pressure differences during breathing that would otherwise collapse them and limit air flow. Changes in biomechanical properties and composition of airway Cartilage may contribute to altered lung function in obstructive lung diseases. To investigate the relationship between collagen organization and equilibrium tensile modulus within the structure of airway Cartilage, we used scanning electron microscopy (SEM), histochemistry and equilibrium tensile testing to analyze Tracheal Cartilage from 10 humans aged 17–81 yr. We show that the surfaces of Tracheal Cartilage matrix are collagen-rich and surround a proteoglycan-rich core. Collagen fibrils in the superficial zones are oriented in the plane of the Cartilage surface. In deeper layers of the Cartilage, collagen fibrils are oriented less regularly. Equilibrium tensile modulus of 100 μm thick strips of Cartilage was measured and was found to decrease with depth; from 13.6±1.5 MPa for the ablumenal superficial zone to 4.6±1.7 MPa in the middle zone (means±S.D., n=10, p ). Stress–strain curves were linear for strains up to 10% with minimal residual strain. This is consistent with a model in which collagen fibres in the outer layers of the Cartilage resist tensile forces, and hydrated proteoglycans in the central zone resist compression forces as the Cartilage crescent bends.
-
mechanical properties of human Tracheal Cartilage
Journal of Applied Physiology, 1992Co-Authors: Jeffrey K Rains, Clive R Roberts, J L Bert, Peter D PareAbstract:Biomechanical changes in airway Cartilage could influence the mechanics of maximal expiratory flow and cough and the degree of shortening of activated airway smooth muscle. We examined the tensile stiffness of small samples of human Tracheal Cartilage rings in specimens obtained at autopsy from 10 individuals who ranged in age from 17 to 81 yr. The tensile properties of the Cartilage were compared with its content of water (%water), glycosaminoglycans (chondroitin sulfate equivalents, mg/mg dry wt), and hydroxyproline content (mg hydroxyproline/mg dry weight). The average values for tensile stiffness ranged between 1 and 15 MPa and increased significantly with increasing age [tensile stiffness = 0.19 x (age in yr) + 2.02; r = 0.83, P less than 0.05]. The outermost layer of Cartilage was the most stiff in all individuals, and the deeper layers were progressively less stiff. Water content and hydroxyproline content both decreased with increasing age. Thus tensile stiffness correlated inversely with water content and hydroxyproline content [tensile stiffness = -0.83 x (%water) + 16.4; r = 0.82, P less than .05 and tensile stiffness = -342 x (hydroxyproline content) + 25; r = 0.87, P less than 0.05]. Total tissue content of glycosaminoglycans did not change with age, although changes in glycosaminoglycan type and proteoglycan structure with increasing age have been described. We conclude that there are age-related changes in the biomechanical properties and biochemical composition of airway Cartilage that could influence airway dynamics.
-
composition changes in human Tracheal Cartilage in growth and aging including changes in proteoglycan structure
American Journal of Physiology-lung Cellular and Molecular Physiology, 1991Co-Authors: Clive R Roberts, Peter D PareAbstract:High-buoyant-density proteoglycans were extracted and purified from Tracheal Cartilage obtained from nine individuals aged 1-58 yr. Cartilage from young individuals contained one major species of extractable aggregating proteoglycan and very little link protein. Link protein concentration relative to proteoglycan was observed to increase during the first 14 years of life, consistent with the increased formation of proteoglycan aggregates that are stabilized by link protein, as the process of Tracheal Cartilage growth and airway lumen widening ends. With increasing age after maturity, two further populations of proteoglycans became more abundant; these were characterized by higher mobility in composite agarose-polyacrylamide gel electrophoresis. The ability of the proteoglycans to associate with hyaluronan decreased with increasing age, although members of each of the three proteoglycan species contained functional hyaluronan-binding domains. Link proteins showed evidence of increasing proteolysis with age. Hydroxyproline content of the Cartilage decreased with age; total tissue glycosaminoglycan and water contents showed no significant changes. Altered proteoglycan charge density, proteoglycan size, and aggregation properties, as well as changes in distribution of proteoglycans, may contribute to the changes in Cartilage biomechanics that are associated with age-dependent changes in human lung function.
-
a method for estimating the young s modulus of complete Tracheal Cartilage rings
Journal of Applied Physiology, 1991Co-Authors: Rodney K Lambert, J L Bert, E M Baile, R H Moreno, Peter D PareAbstract:Cartilage is primarily responsible for maintaining the stability of the large airways; yet very little is known about the mechanical properties of airway Cartilage. This work establishes a technique whereby average values for the equilibrium modulus of excised Tracheal Cartilage rings can be obtained. An apparatus was designed to apply preset deformations to a Tracheal segment and to monitor the deforming force. Segments of four human tracheae obtained postmortem and containing three rings were mounted in the apparatus after being stripped of posterior membrane. The load-deformation behavior was analyzed with a model on the basis of thin curved beam theory. Agreement between predicted deformed shapes and those observed was good in three of the four cases and in the case of a short length of longitudinally split rubber tube. The technique is suitable for comparing mechanical properties of Cartilage before and after an intervention.
