Urètre

L'urètre (orthographié parfois urèthre) est le canal de sortie de la vessie. Il a une fonction excrétrice dans les deux sexes (sortie de l’urine) et de plus chez l’homme une fonction reproductrice (passage du sperme). Urétral (ou uréthral) est l’adjectif correspondant (noter le changement d’accent sur le e). Le sphincter de l'urètre est le muscle qui permet le contrôle volontaire sur la miction. Il ne faut pas confondre l’urètre et l’uretère, qui est le conduit qui part des reins et transporte l'urine vers la vessie. Anatomie Urètre féminin Chez la femme, l’urètre est très court (environ ), pour un diamètre de environ, et débouche sur la vulve entre le clitoris et l’ouverture du vagin par le méat urinaire. Son extrémité distale est appelée ostium urétral. De part et d’autre s’abouchent les glandes para-urétrales ou glandes de Skene. Il est divisé en deux parties, séparées par le muscle urétrovaginal :

l’urètre pelvien, engainé par le sphincter de la vessie

In-vivo performance of high-density collagen gel tubes for urethral regeneration in a rabbit model

Peter Frey, Jeffrey Alan Hubbell, Lionel Ambroise Micol

Congenital malformations or injuries of the urethra can be treated using existing autologous tissue, but these procedures are sometimes associated with severe complications. Therefore, tissue engineering may be advantageous for generating urethral grafts. We evaluated engineered high-density collagen gel tubes as urethral grafts in 16 male New Zealand white rabbits. The constructs were either acellular or seeded with autologous smooth muscle cells, isolated from an open bladder biopsy. After the formation of a urethral defect by excision, the tissue-engineered grafts were interposed between the remaining urethral ends. No catheter was placed postoperatively. The animals were evaluated at 1 or 3 months by contrast urethrography and histological examination. Comparing the graft caliber to the control urethra at 3 months, a larger caliber was found in the cell-seeded grafts (96.6% of the normal caliber) than in the acellular grafts (42.3%). Histology of acellular and cell-seeded grafts did not show any sign of inflammation, and spontaneous regrowth of urothelium could be demonstrated in all grafts. Urethral fistulae, sometimes associated with stenosis, were observed, which might be prevented by urethral catheter application. High-density collagen gel tubes may be clinically useful as an effective treatment of congenital and acquired urethral pathologies. (C) 2012 Elsevier Ltd. All rights reserved.

Elsevier2012

Engineered acellular collagen scaffold for endogenous cell guidance, a novel approach in urethral regeneration

Peter Frey, Jeffrey Alan Hubbell, Hans Mattias Larsson, Kalitha Pinnagoda, Elif Vardar, Ganesh Vythilingam

The treatment of congenital malformations or injuries of the urethra using existing autologous tissues can be associated with post-operative complications. Using rat-tail collagen, we have engineered an acellular high-density collagen tube. These tubes were made of 2 layers and they could sustain greater burst pressures than the monolayered tubes. Although it remains a weak material this 2 layered tube could be sutured to the native urethra. In 20 male New Zealand white rabbits, 2 cm long grafts were sutured in place after subtotal excision of the urethra. This long-term study was performed in Lausanne (Switzerland) and in Kuala Lumpur (Malaysia). No catheter was placed post-operatively. All rabbits survived the surgical implantation. The animals were evaluated at 1, 3, 6, and 9 months by contrast voiding cysto-urethrography, histological examination and immunohistochemistry. Spontaneous re population of urothelial and smooth muscle cells on all grafts was demonstrated. Cellular organization increased with time, however, 20% of both fistula and stenosis could be observed post-operatively. This off-the shelf scaffold with a promising urethral regeneration has a potential for clinical application. Statement of Significance In this study we have tissue engineered a novel cell free tubular collagen based scaffold and used it as a urethral graft in a rabbit model. The novelty of our technique is that the tube can be sutured. Testing showed better burst pressures and the grafts could then be successfully implanted after a urethral excision. This long term study demonstrated excellent biocompatibility of the 2 cm graft and gradual regeneration with time, challenging the current literature. Finally, the main impact is that we describe an off-the-shelf and cost-effective product with comparable surgical outcome to the cellular grafts. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Elsevier Sci Ltd2016

Engineered acellular collagen scaffold for endogenous cell guidance, a novel approach in urethral regeneration

Peter Frey, Jeffrey Alan Hubbell, Hans Mattias Larsson, Kalitha Pinnagoda, Elif Vardar, Ganesh Vythilingam

Elsevier Sci Ltd2016

In-vivo performance of high-density collagen gel tubes for urethral regeneration in a rabbit model

Engineered acellular collagen scaffold for endogenous cell guidance, a novel approach in urethral regeneration

Urethra reconstructions in rabbits using tubular collagen scaffolds seeded with labeled bladder smooth muscle cells

In-vivo performance of high-density collagen gel tubes for urethral regeneration in a rabbit model

Engineered acellular collagen scaffold for endogenous cell guidance, a novel approach in urethral regeneration

Urethra reconstructions in rabbits using tubular collagen scaffolds seeded with labeled bladder smooth muscle cells