title: Additive effects of the Rho kinase inhibitor Y-27632 and vardenafil on relaxation of the corpus cavernosum tissue of patients with erectile dysfunction and clinical phosphodiesterase type 5 inhibitor failure.
abstract: OBJECTIVE
  To evaluate the expression of the Rho/Rho-associated protein kinase (ROCK) pathway in the corpus cavernosum of patients with severe erectile dysfunction (ED) compared with healthy human corpus cavernosum, and to test the functional effects of two Rho kinase inhibitors (RKIs) on erectile tissue of patients with severe ED, which did not respond to phosphodiesterase type 5 inhibitors (PDE5Is).
  
  
  METHODS
  Human corpus cavernosum samples were obtained after consent from men undergoing penile prosthesis implantation (n = 7 for organ bath experiments, n = 17 for quantitative PCR [qPCR]). Potent control subjects (n = 5) underwent penile needle biopsy. qPCR was performed for the expression of RhoA and ROCK subtypes 1 and 2. Immunohistochemistry staining against ROCK and α smooth muscle actin (αSMA) was performed on the corpus cavernosum of patients with ED. Tissue strips were precontracted with phenylephrine and incubated with 1 μm of the PDE5I vardenafil or with DMSO (control). Subsequently, increasing concentrations of the RKIs azaindole or Y-27632 were added, and relaxation of tissue was quantified.
  
  
  RESULTS
  The expression of ROCK1 was unchanged (P > 0.05), while ROCK2 (P < 0.05) was significantly upregulated in patients with ED compared with controls. ROCK1 and ROCK2 protein colocalized with αSMA, confirming the presence of this kinase in cavernous smooth muscle cells and/or myofibroblasts. After incubation with DMSO, 10 μm azaindole and 10 μm Y-27632 relaxed precontracted tissues with 49.5 ± 7.42% (P = 0.1470 when compared with vehicle) and 85.9 ± 10.3% (P = 0.0016 when compared with vehicle), respectively. Additive effects on relaxation of human corpus cavernosum were seen after preincubation with 1 μm vardenafil.
  
  
  CONCLUSIONS
  The RKI Y-27632 causes a significant relaxation of corpus cavernosum in tissue strips of patients with severe ED. The additive effect of vardenafil and Y-27632 shows that a combined inhibition of Rho-kinase and phosphodiesterase type 5 could be a promising orally administered treatment for severe ED.
authors.affiliation: Department of Urology, University Hospitals Leuven, Leuven, Belgium.|Department of Urology, Jessa Hospital, Hasselt University, Hasselt, Belgium.|Department of Development and Regeneration, Cluster Organ Systems, Faculty of Medicine, Group Biomedical Sciences, KU Leuven, Leuven, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Uvin
authors.affiliation: Department of Urology, University Hospitals Leuven, Leuven, Belgium.|Department of Development and Regeneration, Cluster Organ Systems, Faculty of Medicine, Group Biomedical Sciences, KU Leuven, Leuven, Belgium.
authors.forename: Maarten
authors.initials: M
authors.lastname: Albersen
authors.affiliation: Physiology Group, University of Hasselt, Hasselt, Belgium.
authors.forename: Ine
authors.initials: I
authors.lastname: Bollen
authors.affiliation: Physiology Group, University of Hasselt, Hasselt, Belgium.
authors.forename: Maarten
authors.initials: M
authors.lastname: Falter
authors.affiliation: Department of Urology, University Hospitals Leuven, Leuven, Belgium.|Department of Development and Regeneration, Cluster Organ Systems, Faculty of Medicine, Group Biomedical Sciences, KU Leuven, Leuven, Belgium.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Weyne
authors.affiliation: Jessa Hospital, University Biobank Limburg, Hasselt, Belgium.
authors.forename: Loes
authors.initials: L
authors.lastname: Linsen
authors.affiliation: Bayer HealthCare, Global Drug Discovery, Wuppertal, Germany.|Institute of Pharmacology, Hannover Medical School, Hannover, Germany.
authors.forename: Hanna
authors.initials: H
authors.lastname: Tinel
authors.affiliation: Bayer HealthCare, Global Drug Discovery, Wuppertal, Germany.|Institute of Pharmacology, Hannover Medical School, Hannover, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Sandner
authors.affiliation: Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
authors.forename: Trinity J
authors.initials: TJ
authors.lastname: Bivalacqua
authors.affiliation: Department of Urology, University Hospitals Leuven, Leuven, Belgium.|Department of Development and Regeneration, Cluster Organ Systems, Faculty of Medicine, Group Biomedical Sciences, KU Leuven, Leuven, Belgium.
authors.forename: Dirk J M K
authors.initials: DJ
authors.lastname: De Ridder
authors.affiliation: Department of Urology, University Hospitals Leuven, Leuven, Belgium.|Department of Development and Regeneration, Cluster Organ Systems, Faculty of Medicine, Group Biomedical Sciences, KU Leuven, Leuven, Belgium.
authors.forename: Frank
authors.initials: F
authors.lastname: Van der Aa
authors.affiliation: Physiology Group, University of Hasselt, Hasselt, Belgium.
authors.forename: Bert
authors.initials: B
authors.lastname: Brône
authors.affiliation: Department of Urology, University Hospitals Leuven, Leuven, Belgium.|Department of Urology, Jessa Hospital, Hasselt University, Hasselt, Belgium.
authors.forename: Koenraad
authors.initials: K
authors.lastname: Van Renterghem
mesh_terms: D000577:Amides / Q000494:pharmacology*; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007172:Erectile Dysfunction / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010413:Penis / Q000187:drug effects*; D058986:Phosphodiesterase 5 Inhibitors / Q000627:therapeutic use*; D011725:Pyridines / Q000494:pharmacology*; D017211:Treatment Failure; D000069058:Vardenafil Dihydrochloride / Q000494:pharmacology*; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors*
chemical_list: D000577:Amides; D004791:Enzyme Inhibitors; D058986:Phosphodiesterase 5 Inhibitors; D011725:Pyridines; C108830:Y 27632; D000069058:Vardenafil Dihydrochloride; D054460:rho-Associated Kinases
keywords: Rho kinase inhibitor; Rho/Rho associated protein kinase (ROCK) pathway; Y-27632; corpus cavernosum; erectile dysfunction; phosphodiesterase type 5 inhibitor