title: Reduced flow after tubularized incised plate urethroplasty--increased fibrogenesis, elastin fiber loss or neither?
abstract: OBJECTIVE
  Low urinary flow rates are common after tubularized incised plate urethroplasty but the etiology remains unclear and may be related to low urethral compliance due to abnormal collagen concentrations and/or fewer elastic fibers in the healed urethral plate. We hypothesized that inserting a preputial mucosal graft over the dorsal raw area after the midline incision may avoid scarring and improve urethral compliance.
  
  
  METHODS
  Adult rabbits were submitted to tubularized incised plate urethroplasty with or without inlay preputial graft according to a previously described protocol. Tissular concentrations of collagens I, III, IV, VI, VIII and XIII were measured. Histomorphometric analysis was used to quantify elastic fibers in the urethra. Tubularized incised plate urethroplasty with and without inlay preputial graft was compared to normal rabbit urethras (controls).
  
  
  RESULTS
  mRNA concentrations for collagens I, II and XIII were similar between controls and operated rabbits. The proportions between collagens I and III were 1.05, 0.87 and 1.21, respectively, in controls and animals undergoing tubularized incised plate urethroplasty with and without inlay preputial graft. mRNA concentrations for collagen IV and collagens VI/VIII tended to be higher and lower, respectively, in the operated urethras, despite showing statistical significance only for collagen VIII in animals undergoing tubularized incised plate urethroplasty with inlay preputial graft vs controls (p=0.02). The operated animals did not demonstrate a reduced number of elastic fibers in the urethral tissues compared to controls.
  
  
  CONCLUSIONS
  Elastic fiber number and distribution were similar between tubularized incised plate urethroplasty cases and controls, suggesting that decreased concentrations of elastic fibers do not explain the reduced urethral compliance after tubularized incised plate urethroplasty. The raw area determined by the dorsal urethral incision regenerated after standard tubularized incised plate urethroplasty, while cicatrization with fibrosis occurred in correspondence to the grafted areas after tubularized incised plate urethroplasty with inlay preputial graft.
authors: Center for Experimental Surgery, Postgraduate Program in Surgical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Department of Surgery, Division of Pediatric Surgery and Pediatric Urology, Federal Fluminense University and Servidores do Estado Hospital, Rio de Janeiro, Brazil. Electronic address: lisieux@uol.com.br.
authors: Lisieux Eyer
authors: LE
authors: Jesus
authors: Center for Experimental Surgery, Postgraduate Program in Surgical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Alberto
authors: A
authors: Schanaider
authors: Division of Developmental and Stem Cell Biology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors: Tyler
authors: T
authors: Kirwan
authors: Division of Developmental and Stem Cell Biology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors: Karen J
authors: KJ
authors: Aitken
authors: Department of Pathology, Federal Fluminense University and Servidores do Estado Hospital, Rio de Janeiro, Brazil.
authors: Maria L R
authors: ML
authors: Caldas
authors: Department of Pathology, Federal Fluminense University and Servidores do Estado Hospital, Rio de Janeiro, Brazil.
authors: Elissa
authors: E
authors: Fonseca
authors: Division of Pediatric Urology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors: Alexander
authors: A
authors: Marchenko
authors: Division of Pediatric Urology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; Division of Developmental and Stem Cell Biology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors: Darius J
authors: DJ
authors: Bagli
authors: Division of Pediatric Urology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors: João L
authors: JL
authors: Pippi-Salle
mesh_terms: D000818:Animals; D003094:Collagen / Q000378:metabolism; D004195:Disease Models, Animal; D004547:Elastic Tissue / Q000378:metabolism / Q000473:pathology; D004548:Elasticity; D005355:Fibrosis / Q000473:pathology; D008297:Male; D011817:Rabbits; D019651:Plastic Surgery Procedures / Q000379:methods*; D016038:Skin Transplantation; D013524:Surgical Flaps; D014521:Urethra / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D014563:Urodynamics / Q000502:physiology*; D013521:Urologic Surgical Procedures, Male / Q000379:methods*
chemical_list: D003094:Collagen
keywords: collagen; elastin; hypospadias; skin transplantation; urethra