title: Tadalafil effect on metabolic syndrome-associated bladder alterations: an experimental study in a rabbit model.
abstract: BACKGROUND
  Metabolic syndrome (MetS) and lower urinary tract symptoms (LUTS) are often associated. Bladder detrusor hyper-contractility-a major LUTS determinant-is characterized by increased Ras homolog gene family, member A/Rho-associated protein kinase (RhoA/ROCK) signaling, which is often upregulated in MetS.
  
  
  OBJECTIVE
  This study investigated the effects of tadalafil dosing on RhoA/ROCK signaling in bladder, in a rabbit model of high-fat diet (HFD)-induced MetS.
  
  
  METHODS
  Adult male rabbits feeding a HFD for 12 weeks. A subset of HFD animals was treated with tadalafil (2 mg/kg/day, 1 week: the last of the 12 weeks) and compared with HFD and control (feeding a regular diet) rabbits.
  
  
  METHODS
  In vitro contractility studies to evaluate the relaxant effect of the selective ROCK inhibitor, Y-27632, in carbachol precontracted bladder strips. Evaluation of RhoA activation by its membrane translocation. Immunohistochemistry for ROCK expression has been performed to evaluate ROCK expression in bladder from the different experimental groups. mRNA expression of inflammation, pro-fibrotic markers by quantitative RT-PCR has been performed to evaluate the effect of tadalafil on MetS-induced inflammation and fibrosis within the bladder. The in vitro effect of tadalafil on RhoA/ROCK signaling in bladder smooth muscle cells was evaluated by using chemotaxis assay.
  
  
  RESULTS
  Bladder strips from HFD rabbits showed hyper-responsiveness to Y-27632, indicating RhoA/ROCK overactivity in HFD bladder compared with matched controls. Accordingly, the fraction of activated (translocated to the membrane) RhoA as well as ROCK expression are increased in HFD bladder. Tadalafil dosing normalized HFD-induced bladder hypersensitivity to Y-27632, by reducing RhoA membrane translocation and ROCK overexpression. Tadalafil dosing reduced mRNA expression of inflammatory, pro-fibrotic, and hypoxia markers. A direct inhibitory effect of tadalafil on RhoA/ROCK signaling in bladder smooth muscle cell was demonstrated by using chemotaxis assay. Pre-treatment with tadalafil inhibited both basal and PDGF-induced migration of bladder smooth muscle cells.
  
  
  CONCLUSIONS
  Tadalafil dosing reduced RhoA/ROCK signaling and smooth muscle overactivity in an animal model of MetS-associated bladder alterations. Our findings suggest a novel mechanism of action of tadalafil in alleviating LUTS in MetS patients.
authors.affiliation: Sexual Medicine and Andrology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy.
authors.forename: Linda
authors.initials: L
authors.lastname: Vignozzi
authors.forename: Sandra
authors.initials: S
authors.lastname: Filippi
authors.forename: Paolo
authors.initials: P
authors.lastname: Comeglio
authors.forename: Ilaria
authors.initials: I
authors.lastname: Cellai
authors.forename: Annamaria
authors.initials: A
authors.lastname: Morelli
authors.forename: Elena
authors.initials: E
authors.lastname: Maneschi
authors.forename: Erica
authors.initials: E
authors.lastname: Sarchielli
authors.forename: Mauro
authors.initials: M
authors.lastname: Gacci
authors.forename: Marco
authors.initials: M
authors.lastname: Carini
authors.forename: Gabriella Barbara
authors.initials: GB
authors.lastname: Vannelli
authors.forename: Mario
authors.initials: M
authors.lastname: Maggi
mesh_terms: D000577:Amides / Q000494:pharmacology; D000818:Animals; D002243:Carbolines / Q000494:pharmacology*; D059305:Diet, High-Fat; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008297:Male; D024821:Metabolic Syndrome / Q000188:drug therapy* / Q000235:genetics; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D011725:Pyridines / Q000494:pharmacology; D011817:Rabbits; D015398:Signal Transduction / Q000187:drug effects; D000068581:Tadalafil; D015854:Up-Regulation; D001745:Urinary Bladder Diseases / Q000188:drug therapy*; D064804:Urological Agents / Q000494:pharmacology*; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors
chemical_list: D000577:Amides; D002243:Carbolines; D004791:Enzyme Inhibitors; D011725:Pyridines; D064804:Urological Agents; C108830:Y 27632; D000068581:Tadalafil; D054460:rho-Associated Kinases
keywords: LUTS; Metabolic Syndrome; OAB; Prostatic Enlargement; Rabbit Bladder; RhoA/ROCK Signaling; Tadalafil