1066 COMBINATIONS OF SGC STIMULATORS AND PDE5 INHIBITORS AS NEW TREATMENT OPTION FOR DIFFICULT TO TREAT ED PATIENTS WITH INSUFFICIENT RESPONSE TO PDE5 INHIBITOR THERAPY

Laboratory of Regenerative Sexual Medicine, Incheon, South Korea, 2Korea Advanced Institute of Science and Technology (KAIST), Dept. of Biological Sciences and Laboratory for Vascular Biology, Daejeon, South Korea Introduction & Objectives: Men with diabetic erectile dysfunction (ED) often have severe endothelial dysfunction and respond poorly to oral phosphodiesterase-5 inhibitors. Therefore, cavernous endothelial regeneration is a promising strategy for curing diabetic ED. In the present study, we examined whether and how adipose tissue-derived stromal vascular fraction (AD-SVF) promotes cavernous endothelial regeneration and restoring erectile function in diabetic animals. Materials & Methods: Eight-week-old C57BL/6J mice were used and diabetes was induced by intraperitoneal injection of streptozotocin. AD-SVF was isolated from epididymal adipose tissues of green fluorescence protein transgenic mice. At 8 weeks after induction of diabetes, the animals were divided into 6 groups: controls, diabetic mice, and diabetic mice treated with a single intracavernous injection of PBS or AD-SVF (1 × 104 cells, 1 × 105 cells, or 3 × 105 cells/20 μl, respectively). Two weeks later, erectile function was measured by cavernous nerve stimulation. The penis was stained with antibodies to CD31, CD34, phosphohistone H3, phosphoeNOS, and vascular endothelial growth factor-A (VEGF-A). Penis specimens from a separate group of animals were used for cGMP quantification. Results: The highest erectile response was noted in diabetic mice at a concentration of 1 × 105 cells, which reached up to 82% of the control values. Local delivery of AD-SVF significantly increased cavernous endothelial cell proliferation, eNOS phosphorylation, and cGMP expression compared with that in untreated and PBStreated diabetic group. Intracavernous injection of AD-SVF increased cavernous VEGF-A expression and induced recruitment of CD34(+)CD31(-) progenitor cells. Some AD-SVF underwent differentiation into cavernous endothelial cells. Conclusions: These findings indicate that AD-SVF induces recovery of cavernous endothelial integrity and erectile function predominantly by the provision of trophic factors, and in part by direct incorporation and differentiation of injected AD-SVF. The results support the concept of cavernous endothelial regeneration by use of an AD-SVF as a curative therapy for diabetic ED. Source of Funding: This study was supported by a grant of the Korea Healthcare technology R&D Project, Ministry for Health, Welfare & Family Affairs, Republic of Korea (Jun-Kyu Suh, A084511).

1066

Combinations of sGC stimulators and PDE5 inhibitors as new treatment option for difficult to treat ED patients with insufficient response to PDE5 inhibitor therapy

Sandner P.1, Hartmann J.1, Janitschek A.1, Schulte K.1, Heinig R.2, Boettcher M.F.2 1 Bayer Schering Pharma, Dept. of Common Mechanism Research, Wuppertal, Germany, 2Bayer Schering Pharma, Dept. of Clinical Pharmacology, Wuppertal, Germany Introduction & Objectives: Due to low endogenous NO/cGMP levels, a significant subset of the general ED-population exhibits an insufficient response to PDE5i therapy. Stimulators of the soluble guanylate cyclase (sGC) are less NO/cGMPdependent and might be superior in this population. This study investigated the effects of the sGC stimulator BAY 60-4552 alone and combined with the PDE5i vardenafil in the conscious rabbit ED model, in a setting in which PDE5i were ineffective. Materials & Methods: Conscious male chinchilla rabbits (3-4kg) were orally (po) treated with the test compounds or vehicle via gavage, followed by intravenous (iv) injection of the NO-donor sodium nitro-prusside (SNP) in the ear vein, 90 minutes after oral applications. The SNP injections were done in a high dose setting (0.2mg/ kg iv) and a low dose setting (0.02mg/kg iv), corresponding to the general EDpopulation and the PDE5 insufficient responder ED-population, respectively. Penile length was quantified in 5 minutes intervals after SNP injection. Blood pressure and heart rate were monitored via telemetric implants. Results: Under high NO/cGMP conditions the sGC stimulator BAY 60-4552 (3, 10mg/kg po) dose-dependently induced erections in the conscious rabbit similar to that of vardenafil. Under low NO/cGMP conditions, the sGC stimulator BAY 60-4552 (3, 10mg/kg po) induced still significant erections whereas PDE5i were ineffective. However, BAY 60-4552 (3, 10mg/kg po) caused a dose dependent hypotension. Combining a therapeutic dose of Vardenafil (1.0 po) with a low dose of the sGC stimulator BAY 60-4552 (0.1, 0.3 mg/kg po) resulted in substantial penile erections under low NO/cGMP conditions. These combinations elicited only a minor hypotensive effect similar to that of vardenafil. Conclusions: The combination of the sGC stimulator BAY 60-4552 with vardenafil caused significant erections under low NO/cGMP conditions when PDE5i were ineffective. These combinations were well tolerated and caused haemodynamic changes similar to those of PDE5i. Thus, the combination of BAY 60-4552 with vardenafil could become the first effective and safe treatment option for ED patients with insufficient response to PDE5 inhibitor therapy.

1067

Impact of periprostatic implantation of bone marrow-derived, mesenchymal stem cells on the recovery of penile erection in a rat model of cavernous nerve injury

You D.1, Jang M.J.2, Lee J.3, Lee C.1, Cheon S.H.4, Park S.4, Jeong I.G.1, Ahn T.Y.1, Kim C.S.1

Asan Medical Center, University of Ulsan College of Medicine, Dept. of Urology, Seoul, South Korea, 2Asan Medical Center, Cell Therapy Center, Seoul, South Korea, 3Asan Institute for Life Sciences, Asan Medical Center, Laboratory of Cell Therapy and Stem Cell Biology, Seoul, South Korea, 4Ulsan University Hospital, Dept. of Urology, Ulsan, South Korea 1

Introduction & Objectives: Post-prostatectomy erectile dysfunction is a common complication of radical prostatectomy (RP) and it decreases the quality of life of the patient. It typically results from injury to the cavernous nerve (CN) which courses along the posterolateral aspects of the prostate and provides most of the autonomic input to the erectile tissue. We evaluated the effect of periprostatic implantation of mesenchymal stem cells (MSC) on the recovery of penile erection in a rat model of CN injury. Materials & Methods: Forty, eight-week-old, male Sprague-Dawley rats were randomly divided into four groups (ten rats per group) as follows: 1) only laparotomy (sham group); 2) bilateral CN dissection (BCND) and 0.1 mol/L phosphate-buffered saline instillation (injured control group); 3) BCND and fibrin glue instillation (fibrin glue group); and 4) BCND and periprostatic implantation of MSC with fibrin glue (MSC group). Four week following implantation, systemic arterial pressure (AP) and intracavernosal pressure (ICP) were recorded. To compare erectile function among the groups, the maximal ICP (ICPmax) was divided by the simultaneous AP (ICPmax/AP). After the function evaluation, the penis and bilateral prostate lobes of each rat were harvested and cryopreserved in liquid nitrogen for cGMP expression analysis and observation of nanoparticle-tagged MSC, respectively. Results: Mean ICPmax/AP ± S.E.M was significantly decreased in the injured control and fibrin glue groups (23.2% ± 7.1 and 24.4% ± 5.3, respectively) compared with that of the sham group (64.2% ± 5.0)(p=0.001 and p<0.001, respectively). Mean ICPmax/AP of the MSC group (41.5% ± 4.2) was lower than that of the sham group (p=0.005), although it was higher than those of the injured control and fibrin glue groups (p=0.010 and p=0.023, respectively). Mean cGMP ± S.E.M was decreased in the injured control and fibrin glue groups (5.27 fmol/mg ± 0.26 and 5.03 fmol/mg ± 0.22, respectively) compared with that of the sham group (5.87 fmol/mg ± 0.19)(p=0.126 and p=0.029, respectively). Mean cGMP of the MSC group (5.86 fmol/mg ± 0.25) was similar to that of the sham group (p=0.905). From the harvested prostate, merging of DAPI (4',6-diamidino-2-phenylindole) and nanoparticle was identified, indicating the presence of viable MSC. In addition, several MSCs were stained with S100β antibody, a marker of neuroglial cells. Conclusions: Following the periprostatic implantation of MSC in a rat model with CN injury, the recovery of penile erection was noted. The possible mechanism might include the differentiation of MSC into neuroglial cells and resulting in inhibiting demyelination of the CN and assisting in axonal regeneration.

1068

Inhibition of collagen deposition in corpus caversnosa using human mesenchymal stem cells for the repair of erectile dysfunction in rats with cavernous nerve injury

Song Y.S.1, Lee H.J.2, Doo S.W.1, Yang W.J.1, Lee S.J.3, Kim S.U.2, Ryu J.K.4, Suh J.K.4 1 Soonchunhyang University College of Medicine, Dept. of Urology, Seoul, South Korea, 2Chungang University College of Medicine, Medical Research Institute, Seoul, South Korea, 3Kyunghee University College of Medicine, Dept. of Urology, Seoul, South Korea, 4Inha University College of Medicine, Dept. of Urology, Incheon, South Korea Introduction & Objectives: Collagen deposition in corpus caversnosa may be developed after cavernous nerve injury. Transplantation of mesenchymal stem cells is used for the inhibition of collagen deposition in lung and liver. This study was performed to investigate the inhibition of collagen deposition in corpus caversnosa using human mesenchymal stem cells for the repair of erectile dysfunction in rats with cavernous nerve injury. Materials & Methods: hMSCs were prepared, confirmed. Their pleuripotental differentiation was examined. Eight week old male Sprague-Dawley rats were divided into 3 groups of 10 each, including group 1=sham operation, group 2= cavernous nerve injury, group 3= hMSCs treatment after cavernous nerve injury. Immediately after the cavernous nerve injury in group 3, 1×106 hMSCs hMSCs was injected into the cavernous nerve injured corpus cavernosa. Erectile response was assessed by cavernosal nerve stimulation at 2, 4 weeks including intracavernous pressure/mean arterial pressure(ICP/MAP), total ICP/MAP, Slope/MAP. Thereafter, penile tissue samples were harvested and immunohistochemical and Masson’s trichrome staining was performed. Each slide was inspected microscopically and the mean percent collagen area was examined. Results: hMSCs were confirmed by the stem cell markers and capable of differentiation into osteocytes using alkaline phosphatase staining and Von Kossa staining, chondrocytes using Toluidine blue staining, and adipocytes using oil red O staining in vitro. The mean percent collagen area of corpus caversnosa in sham group was 7.4±1.1. It increased in group 2(13.7±0.2) and recovered in group 3(9.6± 1.1) at 2 weeks after injection of hMSCs(P<0.05). It increased in group 2(14.3±1.4) and recovered in group 3(8.8± 3.0) at 4 weeks after injection of hMSCs(P<0.05). At 2, 4 weeks, the group with cavernous nerve injury had significantly lower ICP/ MAP, total ICP/MAP, Slope/MAP in 1 or 5 V electrical stimulation than the group without cavernous nerve injury(p<0.05). The group transplanted with hMSCs

Eur Urol Suppl 2011;10(2):329