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Christopher R. Chapple - One of the best experts on this subject based on the ideXlab platform.
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Tissue engineered Buccal Mucosa for urethroplasty: Progress and future directions
Advanced Drug Delivery Reviews, 2014Co-Authors: Nadir I. Osman, Christopher Hillary, Anthony J. Bullock, Sheila Macneil, Christopher R. ChappleAbstract:Abstract Purpose Autologous Buccal Mucosa is commonly utilized in the surgical treatment of urethral strictures. Extensive strictures require a larger quantity of tissue, which may lead to donor site morbidity. This review assesses progress in producing tissue engineered Buccal Mucosa as an alternative graft material. Results Few clinical studies have introduced cells onto biological or synthetic scaffolds and implanted resulting constructs in patients. The available studies show that Buccal Mucosa cells on acellular human dermis or on collagen matrix lead to good acute stage tissue integration. Urothelial cells on a synthetic substrate also perform well. However while some patients do well many years post-grafting, others develop stricture recurrence. Acellular biomaterials used to treat long urethral defects in animals commonly lead to fibrosis. Conclusions Tissue engineered Buccal Mucosa shows promise as a substitute for native tissue. The fibrosis which occurs months post-implantation may reflect the underlying disease process recurring in these patients.
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tissue engineered Buccal Mucosa urethroplasty clinical outcomes
European Urology, 2008Co-Authors: Sheila Macneil, S Bhargava, Jacob M Patterson, Richard Inman, Christopher R. ChappleAbstract:Abstract Introduction Whilst Buccal Mucosa is the most versatile tissue for urethral replacement, the quest continues for an ideal tissue replacement for the urethra when substantial tissue transfer is needed. Previously we described the development of autologous tissue-engineered Buccal Mucosa (TEBM). Here we report clinical outcomes of the first human series of its use in substitution urethroplasty. Methodology Five patients with urethral stricture secondary to lichen sclerosus (LS) awaiting substantial substitution urethroplasty elected to undergo urethroplasty using TEBM, with full ethics committee support. Buccal Mucosa biopsies (0.5cm) were obtained from each patient. Keratinocytes and fibroblasts were isolated and cultured, seeded onto sterilised donor de-epidermised dermis, and maintained at air–liquid interface for 7–10 d to obtain full-thickness grafts. These grafts were used for urethroplasty in a one-stage ( n =2) or a two-stage procedure ( n =3). Follow-up was performed at 2 and 6 wk, at 3, 6, 9, and 12 mo, and every 6 mo thereafter. Results Follow-up ranged from 32 to 37 mo (mean, 33.6). The initial graft take was 100%, as assessed by visual inspection. Subsequently, one patient had complete excision of the grafted urethra and one required partial graft excision, for fibrosis and hyperproliferation of tissue, respectively. Three patients have a patent urethra with the TEBM graft in situ, although all three required some form of instrumentation. Conclusions Whilst TEBM may in the future offer a clinically useful autologous urethral replacement tissue, in this group of patients with LS urethral strictures, it was not without complications, namely fibrosis and contraction in two of five patients.
S Bhargava - One of the best experts on this subject based on the ideXlab platform.
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tissue engineered Buccal Mucosa urethroplasty clinical outcomes
European Urology, 2008Co-Authors: Sheila Macneil, S Bhargava, Jacob M Patterson, Richard Inman, Christopher R. ChappleAbstract:Abstract Introduction Whilst Buccal Mucosa is the most versatile tissue for urethral replacement, the quest continues for an ideal tissue replacement for the urethra when substantial tissue transfer is needed. Previously we described the development of autologous tissue-engineered Buccal Mucosa (TEBM). Here we report clinical outcomes of the first human series of its use in substitution urethroplasty. Methodology Five patients with urethral stricture secondary to lichen sclerosus (LS) awaiting substantial substitution urethroplasty elected to undergo urethroplasty using TEBM, with full ethics committee support. Buccal Mucosa biopsies (0.5cm) were obtained from each patient. Keratinocytes and fibroblasts were isolated and cultured, seeded onto sterilised donor de-epidermised dermis, and maintained at air–liquid interface for 7–10 d to obtain full-thickness grafts. These grafts were used for urethroplasty in a one-stage ( n =2) or a two-stage procedure ( n =3). Follow-up was performed at 2 and 6 wk, at 3, 6, 9, and 12 mo, and every 6 mo thereafter. Results Follow-up ranged from 32 to 37 mo (mean, 33.6). The initial graft take was 100%, as assessed by visual inspection. Subsequently, one patient had complete excision of the grafted urethra and one required partial graft excision, for fibrosis and hyperproliferation of tissue, respectively. Three patients have a patent urethra with the TEBM graft in situ, although all three required some form of instrumentation. Conclusions Whilst TEBM may in the future offer a clinically useful autologous urethral replacement tissue, in this group of patients with LS urethral strictures, it was not without complications, namely fibrosis and contraction in two of five patients.
Sheila Macneil - One of the best experts on this subject based on the ideXlab platform.
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Tissue engineered Buccal Mucosa for urethroplasty: Progress and future directions
Advanced Drug Delivery Reviews, 2014Co-Authors: Nadir I. Osman, Christopher Hillary, Anthony J. Bullock, Sheila Macneil, Christopher R. ChappleAbstract:Abstract Purpose Autologous Buccal Mucosa is commonly utilized in the surgical treatment of urethral strictures. Extensive strictures require a larger quantity of tissue, which may lead to donor site morbidity. This review assesses progress in producing tissue engineered Buccal Mucosa as an alternative graft material. Results Few clinical studies have introduced cells onto biological or synthetic scaffolds and implanted resulting constructs in patients. The available studies show that Buccal Mucosa cells on acellular human dermis or on collagen matrix lead to good acute stage tissue integration. Urothelial cells on a synthetic substrate also perform well. However while some patients do well many years post-grafting, others develop stricture recurrence. Acellular biomaterials used to treat long urethral defects in animals commonly lead to fibrosis. Conclusions Tissue engineered Buccal Mucosa shows promise as a substitute for native tissue. The fibrosis which occurs months post-implantation may reflect the underlying disease process recurring in these patients.
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tissue engineered Buccal Mucosa urethroplasty clinical outcomes
European Urology, 2008Co-Authors: Sheila Macneil, S Bhargava, Jacob M Patterson, Richard Inman, Christopher R. ChappleAbstract:Abstract Introduction Whilst Buccal Mucosa is the most versatile tissue for urethral replacement, the quest continues for an ideal tissue replacement for the urethra when substantial tissue transfer is needed. Previously we described the development of autologous tissue-engineered Buccal Mucosa (TEBM). Here we report clinical outcomes of the first human series of its use in substitution urethroplasty. Methodology Five patients with urethral stricture secondary to lichen sclerosus (LS) awaiting substantial substitution urethroplasty elected to undergo urethroplasty using TEBM, with full ethics committee support. Buccal Mucosa biopsies (0.5cm) were obtained from each patient. Keratinocytes and fibroblasts were isolated and cultured, seeded onto sterilised donor de-epidermised dermis, and maintained at air–liquid interface for 7–10 d to obtain full-thickness grafts. These grafts were used for urethroplasty in a one-stage ( n =2) or a two-stage procedure ( n =3). Follow-up was performed at 2 and 6 wk, at 3, 6, 9, and 12 mo, and every 6 mo thereafter. Results Follow-up ranged from 32 to 37 mo (mean, 33.6). The initial graft take was 100%, as assessed by visual inspection. Subsequently, one patient had complete excision of the grafted urethra and one required partial graft excision, for fibrosis and hyperproliferation of tissue, respectively. Three patients have a patent urethra with the TEBM graft in situ, although all three required some form of instrumentation. Conclusions Whilst TEBM may in the future offer a clinically useful autologous urethral replacement tissue, in this group of patients with LS urethral strictures, it was not without complications, namely fibrosis and contraction in two of five patients.
Young-wook Choi - One of the best experts on this subject based on the ideXlab platform.
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Ex Vivo Permeability Characteristics of Porcine Buccal Mucosa to Drugs with Various Polarity
Journal of Korean Pharmaceutical Sciences, 2005Co-Authors: Jae-hwi Lee, Yoon-jin Lee, Mi-kyeong Yoon, Young-wook ChoiAbstract:The aim of this study was to analyze characteristics of the barrier function of excised porcine Buccal Mucosa to the test compounds, estradiol, propranolol HCI, melatonin, and mannitol with a wide range of partition coefficient values. The permeability of melatonin was measured through frozen, stored, and fresh porcine Buccal Mucosa to examine the impact of storage conditions on the permeability of porcine Buccal Mucosa. The results demonstrated that the ex vivo permeability of the porcine Buccal Mucosa was greater for more lipophilic solutes, which was consistent with a series of molecules transported by passive transepithelial diffusion. The melatonin permeation profiles through frozen, stored, and fresh Mucosa illustrated that damage was incurred by the freezing process of the Mucosal tissue, leading to loss of the barrier function and thereby an increased permeation coefficient. It can be observed that the influence of compound lipophilicity on the association of the compounds with Buccal Mucosa was clear. The relationship between permeation coefficient and Log P values for the four compounds investigated demonstrated a proportional relationship, further confirming the importance of the lipophilicity of a compound to permeate the Buccal Mucosa. These results showed that the ex vivo porcine Buccal Mucosa model is a suitable tool to screen oral Mucosal permeability.
Jette Jacobsen - One of the best experts on this subject based on the ideXlab platform.
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Ex Vivo Correlation of the Permeability of Metoprolol Across Human and Porcine Buccal Mucosa
Journal of Pharmaceutical Sciences, 2014Co-Authors: Emil Meng-lund, Eva Marxen, Birgitte Hyrup, Anne Marie Lynge Pedersen, Rene Holm, Anette Mullertz, Jette JacobsenAbstract:ABSTRACT The pH partition theory proposes a correlation between fraction of unionized drug substance and permeability. The aim of this study was to compare the permeability of metoprolol and mannitol in ex vivo human and porcine Buccal Mucosa models at varying pH to validate whether the porcine permeability model is predictive for human Buccal absorption. Human ( n = 9-10) and porcine ( n = 6-7) Buccal Mucosa were mounted in a modified Ussing chamber, and the kinetics of metoprolol and mannitol transport was assessed for a period of 5.5 h with the pH values of donor medium set at 7.4, 8.5, and 9.0. In addition, hematoxylin-eosin and Alcian blue-van Gieson were used as tissue stains to evaluate the histology and the presence of acidic polysaccharides (e.g., mucins), respectively. The permeability of metoprolol was decreased in human Buccal Mucosa by almost twofold when compared with porcine Buccal Mucosa with a positive correlation ( r 2 = 0.96) between the permeability assessed in porcine and human Buccal Mucosa. There was no change in the degree of either epithelial swelling or desquamation when treating with the pH 9.0 donor medium for 5.5 h. These data suggest that Buccal Mucosa from pigs can be used to predict human Buccal absorption.
