Cell-seeded tubularized scaffolds for reconstruction of long urethral defects

A preclinical study

Hazem Orabi, Tamer Aboushwareb, Yuanyuan Zhang, James J. Yoo, Anthony Atala

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

Background: The treatment options for patients requiring repair of a long segment of the urethra are limited by the availability of autologous tissues. We previously reported that acellular collagen-based tubularized constructs seeded with cells are able to repair small urethral defects in a rabbit model. Objective: We explored the feasibility of engineering clinically relevant long urethras for surgical reconstruction in a canine preclinical model. Design, setting, and participants: Autologous bladder epithelial and smooth muscle cells from 15 male dogs were grown and seeded onto preconfigured collagen-based tubular matrices (6 cm in length). The perineal urethral segment was removed in 21 male dogs. Urethroplasties were performed with tubularized collagen scaffolds seeded with cells in 15 animals. Tubularized constructs without cells were implanted in six animals. Serial urethrography and three-dimensional computed tomography (CT) scans were performed pre- and postoperatively at 1, 3, 6, and 12 mo. The animals were euthanized at their predetermined time points (three animals at 1 mo, and four at 3, 6, and 12 mo) for analyses. Outcome measurements and statistical analysis: Statistical analysis of CT imaging and histology was not needed. Results and limitations: CT urethrograms showed wide-caliber urethras without strictures in animals implanted with cell-seeded matrices. The urethral segments replaced with acellular scaffolds collapsed. Gross examination of the urethral implants seeded with cells showed normal-appearing tissue without evidence of fibrosis. Histologically, an epithelial cell layer surrounded by muscle fiber bundles was observed on the cell-seeded constructs, and cellular organization increased over time. The epithelial and smooth muscle phenotypes were confirmed using antibodies to pancytokeratins AE1/AE3 and smooth muscle-specific desmin. Formation of an epithelial cell layer occurred in the unseeded constructs, but few muscle fibers formed. Conclusions: Cell-seeded tubularized collagen scaffolds can be used to repair long urethral defects, whereas scaffolds without cells lead to poor tissue development and strictures. This study demonstrates that long tissue-engineered tubularized urethral segments may be used for urethroplasty in patients.

Original languageEnglish
Pages (from-to)531-538
Number of pages8
JournalEuropean Urology
Volume63
Issue number3
DOIs
StatePublished - Mar 1 2013
Externally publishedYes

Fingerprint

Urethra
Collagen
Tomography
Smooth Muscle
Pathologic Constriction
Epithelial Cells
Dogs
Muscles
Desmin
Smooth Muscle Myocytes
Canidae
Histology
Urinary Bladder
Fibrosis
Rabbits
Phenotype
Antibodies
Therapeutics

Keywords

  • Cell-seeded tubularized urethra reconstruction
  • Stricture repair
  • Tissue-engineered urethra
  • Urethra

ASJC Scopus subject areas

  • Urology

Cite this

Cell-seeded tubularized scaffolds for reconstruction of long urethral defects : A preclinical study. / Orabi, Hazem; Aboushwareb, Tamer; Zhang, Yuanyuan; Yoo, James J.; Atala, Anthony.

In: European Urology, Vol. 63, No. 3, 01.03.2013, p. 531-538.

Research output: Contribution to journalArticle

Orabi, Hazem ; Aboushwareb, Tamer ; Zhang, Yuanyuan ; Yoo, James J. ; Atala, Anthony. / Cell-seeded tubularized scaffolds for reconstruction of long urethral defects : A preclinical study. In: European Urology. 2013 ; Vol. 63, No. 3. pp. 531-538.
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abstract = "Background: The treatment options for patients requiring repair of a long segment of the urethra are limited by the availability of autologous tissues. We previously reported that acellular collagen-based tubularized constructs seeded with cells are able to repair small urethral defects in a rabbit model. Objective: We explored the feasibility of engineering clinically relevant long urethras for surgical reconstruction in a canine preclinical model. Design, setting, and participants: Autologous bladder epithelial and smooth muscle cells from 15 male dogs were grown and seeded onto preconfigured collagen-based tubular matrices (6 cm in length). The perineal urethral segment was removed in 21 male dogs. Urethroplasties were performed with tubularized collagen scaffolds seeded with cells in 15 animals. Tubularized constructs without cells were implanted in six animals. Serial urethrography and three-dimensional computed tomography (CT) scans were performed pre- and postoperatively at 1, 3, 6, and 12 mo. The animals were euthanized at their predetermined time points (three animals at 1 mo, and four at 3, 6, and 12 mo) for analyses. Outcome measurements and statistical analysis: Statistical analysis of CT imaging and histology was not needed. Results and limitations: CT urethrograms showed wide-caliber urethras without strictures in animals implanted with cell-seeded matrices. The urethral segments replaced with acellular scaffolds collapsed. Gross examination of the urethral implants seeded with cells showed normal-appearing tissue without evidence of fibrosis. Histologically, an epithelial cell layer surrounded by muscle fiber bundles was observed on the cell-seeded constructs, and cellular organization increased over time. The epithelial and smooth muscle phenotypes were confirmed using antibodies to pancytokeratins AE1/AE3 and smooth muscle-specific desmin. Formation of an epithelial cell layer occurred in the unseeded constructs, but few muscle fibers formed. Conclusions: Cell-seeded tubularized collagen scaffolds can be used to repair long urethral defects, whereas scaffolds without cells lead to poor tissue development and strictures. This study demonstrates that long tissue-engineered tubularized urethral segments may be used for urethroplasty in patients.",
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AB - Background: The treatment options for patients requiring repair of a long segment of the urethra are limited by the availability of autologous tissues. We previously reported that acellular collagen-based tubularized constructs seeded with cells are able to repair small urethral defects in a rabbit model. Objective: We explored the feasibility of engineering clinically relevant long urethras for surgical reconstruction in a canine preclinical model. Design, setting, and participants: Autologous bladder epithelial and smooth muscle cells from 15 male dogs were grown and seeded onto preconfigured collagen-based tubular matrices (6 cm in length). The perineal urethral segment was removed in 21 male dogs. Urethroplasties were performed with tubularized collagen scaffolds seeded with cells in 15 animals. Tubularized constructs without cells were implanted in six animals. Serial urethrography and three-dimensional computed tomography (CT) scans were performed pre- and postoperatively at 1, 3, 6, and 12 mo. The animals were euthanized at their predetermined time points (three animals at 1 mo, and four at 3, 6, and 12 mo) for analyses. Outcome measurements and statistical analysis: Statistical analysis of CT imaging and histology was not needed. Results and limitations: CT urethrograms showed wide-caliber urethras without strictures in animals implanted with cell-seeded matrices. The urethral segments replaced with acellular scaffolds collapsed. Gross examination of the urethral implants seeded with cells showed normal-appearing tissue without evidence of fibrosis. Histologically, an epithelial cell layer surrounded by muscle fiber bundles was observed on the cell-seeded constructs, and cellular organization increased over time. The epithelial and smooth muscle phenotypes were confirmed using antibodies to pancytokeratins AE1/AE3 and smooth muscle-specific desmin. Formation of an epithelial cell layer occurred in the unseeded constructs, but few muscle fibers formed. Conclusions: Cell-seeded tubularized collagen scaffolds can be used to repair long urethral defects, whereas scaffolds without cells lead to poor tissue development and strictures. This study demonstrates that long tissue-engineered tubularized urethral segments may be used for urethroplasty in patients.

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KW - Stricture repair

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KW - Urethra

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