vardenafil-dihydrochloride and Urinary-Bladder--Overactive

Phosphodiesterase type 5 inhibitors (PDE5-Is) improve storage symptoms in benign prostatic hyperplasia patients, despite a lack of effect on peak urinary flow rate. Moreover, vardenafil improves urodynamic parameters in spinal cord-injured (SCI) patients with neurogenic detrusor overactivity (NDO). SCI rats also display NDO characterized by nonvoiding contractions (NVCs) during bladder filling, resulting in an increased bladder afferent nerve firing (BANF).. We postulated that vardenafil could improve urodynamic parameters by reducing BANF. The effect of vardenafil has been investigated on intravesical pressure by cystometry experiments while recording BANF in response to bladder filling.. Complete T7-T8 spinalization was performed in 15 female adult Sprague-Dawley rats (250-275 g).. At 21-29 d postspinalization, fine filaments were dissected from the L6 dorsal roots and placed across a bipolar electrode. Bladder afferent nerve fibers were identified by electrical stimulation of the pelvic nerve and bladder distension. SCI rats were decerebrated before cystometry experiments. Bladders were filled to determine the maximal bladder filling volume (BFV) for each rat. Then, after bladder stabilization at 75% of maximal BFV, saline (n=7) or vardenafil 1 mg/kg (n=8) was delivered intravenously. NVCs and BANF were recorded for 45 min.. In all SCI rats, BANF was already present and regular at resting conditions (26.2±4.1 spikes per second). During bladder filling, intravesical pressure (IVP) slowly increased with transient NVCs superimposed. Concomitantly, BANF progressively increased up to 2.4-fold at maximal BFV (2.08±0.24 ml). After stabilization at submaximal BFV, BANF was increased by 186±37%. Vardenafil injection induced an immediate decrease in NVCs compared to saline (p<0.001) and BANF (52% decrease vs 28% in saline after 45 min; p<0.001).. Systemic vardenafil reduced both NVCs and BANF in unanesthetized, decerebrate, SCI rats. These findings provide new insights into the mechanism of action by which PDE5-Is improve storage symptoms in SCI patients.

Topics: Animals; Decerebrate State; Disease Models, Animal; Female; Imidazoles; Neurons, Afferent; Phosphodiesterase 5 Inhibitors; Piperazines; Pressure; Rats; Rats, Sprague-Dawley; Spinal Cord Injuries; Spinal Nerve Roots; Sulfones; Triazines; Urinary Bladder; Urinary Bladder, Overactive; Vardenafil Dihydrochloride

In human bladder, phosphodiesterase type 5 (PDE5) is present not only in the muscular wall but also in the vascular beds, suggesting a role for PDE5 inhibitors in favoring bladder blood flow and tissue oxygenation.. To investigate whether acute administration of vardenafil could affect bladder oxygenation in spontaneously hypertensive rats (SHR), an animal model of naturally occurring overactive bladder.. The effect of vardenafil on hypoxia-induced alterations was studied in vivo in SHR by acute dosing (10 mg/kg, 90 minutes before sacrifice) and in vitro in human bladder smooth muscle cells (hBCs).. Bladder oxygenation was detected using the hypoxyprobe immunostaining. The expression of some hypoxia markers (vascular endothelial growth factor [VEGF] and endothelin-1 type B [ETB] receptor) was also evaluated by immunohistochemistry and Western blot. Gene expression in hBC was quantified by real-time reverse transcription-polymerase chain reaction.. Rat bladder PDE5 immunopositivity was detected in the muscular wall and in the endothelial and smooth muscle cells of blood vessels. In SHR bladder, a significant increase of hypoxic cells, VEGF, and ETB expression was observed when compared with their normotensive counterpart Wistar Kyoto rats (WKY). Vardenafil treatment dramatically decreased hypoxyprobe staining, as well as VEGF and ETB expression in SHR bladder up to WKY level. Accordingly, in SHR bladder, vardenafil administration significantly blunted relaxation induced by the selective ETB agonist IRL-1620. In hBCs, experimental hypoxia significantly induced gene expression of hypoxia markers (carbonic anhydrase IX and VEGF), which was not changed by simultaneous treatment with vardenafil. Conversely, the hypoxia-related induction of smooth muscle-specific genes (alphaSMA, SM22alpha, and desmin) was significantly reduced by vardenafil.. SHR showed bladder hypoxia which was significantly reduced by acute vardenafil treatment. Thus, besides relaxing muscular wall, PDE5 inhibition may positively affect urinary vesicle blood perfusion.

Topics: Animals; Cells, Cultured; Cyclic Nucleotide Phosphodiesterases, Type 5; Drug Administration Schedule; Gene Expression Regulation, Enzymologic; Hypoxia; Imidazoles; Immunoenzyme Techniques; Male; Muscle, Smooth; Oxygen Consumption; Piperazines; Prostatic Hyperplasia; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptor, Endothelin B; RNA, Messenger; Sulfones; Triazines; Urinary Bladder; Urinary Bladder, Overactive; Vardenafil Dihydrochloride; Vascular Endothelial Growth Factor A; Vasodilator Agents

Phosphodiesterase type 5 inhibitors (PDE5i), the most widely used drugs for erectile dysfunction, could also improve lower urinary tract symptoms, essentially due to overactive bladder (OAB), a condition hypothesized to be a result of an increased RhoA/Rho-kinase (ROCK) signaling. Phosphorylation/inactivation of RhoA by cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG) activity has been described in vascular smooth muscle.. The aim of this paper was to investigate whether vardenafil-induced cGMP accumulation reduces RhoA/ROCK signaling in bladder.. Spontaneously hypertensive rats (SHRs), a strain genetically prone to develop OAB, were treated with vardenafil (10 mg/kg/day) for 2 weeks. Wistar-Kyoto rats (WKY) were used as control. In vitro experiments were performed in human bladder smooth muscle cells (hBCs).. Urodynamic parameters were registered in vivo in anesthetized WKY and SHRs. RhoA/ROCK activity in bladder was evaluated by molecular and functional studies in tissues and cells.. The intercontraction interval and bladder capacity, and were decreased in SHRs and restored by vardenafil. The in vitro relaxant effect of the ROCK inhibitor Y-27632 was higher in bladder strips from SHR than from WKY and reduced by vardenafil. Nomega-nitro-L-arginine-methyl-ester (a NO-synthase inhibitor, 40 mg/kg/day during the last week of the 2-week treatment with vardenafil) partially antagonized vardenafil effect on Y-27632 responsiveness. Vardenafil prevented RhoA membrane translocation/activation, decreased ROCK activity, and increased cGMP levels in vivo (rat) and in vitro (hBCs). Exposing hBCs to vardenafil increased Ser(188) RhoA phosphorylation, to the same extent as the PDE5-insensitive PKG agonist Sp-8-Br-PET-cGMP. Moreover, vardenafil inhibited several RhoA-dependent functions in hBCs, including smooth muscle gene transcription and endothelin-1-induced migration. These effects were reverted by the PKG inhibitor KT 5823, further suggesting a cGMP/PKG-dependency. In hBCs, vardenafil was active in the low nanomolar range.. This is the first study demonstrating that the effect of vardenafil on OAB could be partially determined by a cGMP-dependent RhoA/ROCK signaling inhibition.

Topics: Animals; Blotting, Western; Cyclic GMP; Hypertension; Imidazoles; Muscle Contraction; Muscle, Smooth; Phosphodiesterase 5 Inhibitors; Phosphodiesterase Inhibitors; Piperazines; Rats; Reverse Transcriptase Polymerase Chain Reaction; rho-Associated Kinases; rhoA GTP-Binding Protein; Signal Transduction; Sulfones; Triazines; Urinary Bladder, Overactive; Urodynamics; Vardenafil Dihydrochloride