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PDE5 Expression (pde5 + expression)
Selected AbstractsCharacterization of Phosphodiesterase Type 5 Expression and Functional Activity in the Human Male Lower Urinary TractTHE JOURNAL OF SEXUAL MEDICINE, Issue 1pt1 2010Benedetta Fibbi MD ABSTRACT Introduction., Phosphodiesterase type 5 (PDE5) inhibitors ameliorate low urinary tract (LUT) symptoms in men with ED and symptomatic benign prostatic hyperplasia (BPH). PDE5 is highly expressed in rat and human bladder, where it regulates cyclic guanosine monophosphate (cGMP) degradation, muscle tone, and proliferation. Aim., To investigate PDE5 tissue distribution and activity in human LUT tissues (urethra, prostate, and bladder). Main Outcome Measures., PDE5 expression and activity were analyzed and compared within the same BPH patient in LUT tissues and in smooth muscle cells (SMCs) cultured from urethra, prostate, and bladder. Methods., In LUT tissues, PDE5 was localized by immunohistochemistry and mRNA expression by quantitative real-time polymerase chain reaction. Proliferation assay was used as readout of PDE5 activity, evaluated as ability of vardenafil to increase the antiproliferative effect of different nitric oxide (NO)/cGMP pathway activators [the PDE5-resistant cGMP analog Sp-8-Br-PET-cGMPS, the NO donor sodium nitroprusside (SNP), and the soluble guanylate cyclase (sGC) stimulator BAY 41-8543]. Results., In all the LUT tissues, PDE5 was immunolocalized in blood vessels and in muscular fibres, but not in epithelium. PDE5 mRNA expression was higher in urethra and bladder than in prostate SMC. The antiproliferative effect of Sp-8-Br-PET-cGMPS was similar in all LUT SMC. In prostatic SMC, SNP and BAY 41-8543 show a dose-dependent antiproliferative effect that resulted marginally enhanced by vardenafil. Conversely, in urethra and bladder SMC the antiproliferative effect of SNP and BAY 41-8543 was lower than in prostatic SMC, but it was significantly enhanced by vardenafil. In urethral and bladder cells vardenafil half-maximal response inhibiting concentration was in the subnanomolar range, whereas in prostate cells it resulted significantly higher. Conclusions., The highest expression and biological activity of PDE5 was found in bladder. However, a consistent PDE5 expression and activity was also found in prostatic urethra. In contrast, the prostate gland showed the lowest PDE5 abundance and cultures derived from this tissue were less sensitive to vardenafil. Fibbi B, Morelli A, Vignozzi L, Filippi S, Chavalmane A, De Vita G, Marini M, Gacci M, Vannelli GB, Sandner P, and Maggi M. Characterization of phosphodiesterase type 5 expression and functional activity in the human male lower urinary tract. J Sex Med 2010;7:59,69. [source] ORIGINAL RESEARCH,BASIC SCIENCE: Cavernous Neurotomy in the Rat is Associated with the Onset of an Overt Condition of HypogonadismTHE JOURNAL OF SEXUAL MEDICINE, Issue 5 2009Linda Vignozzi MD ABSTRACT Background., Most men following radical retropubic prostatectomy (RRP) are afflicted by erectile dysfunction (ED). RRP-related ED occurs as a result of surgically elicited neuropraxia, leading to histological changes in the penis, including collagenization of smooth muscle and endothelial damage. Aim., To verify whether hypogonadism could contribute to the pathogenesis of RRP-ED. Methods., Effects of testosterone (T), alone or in association with long-term tadalafil (Tad) treatment in a rat model of bilateral cavernous neurotomy (BCN). Main Outcome Measures., Penile tissues from rats were harvested for vasoreactivity studies 3 months post-BCN. Penile oxygenation was evaluated by hypoxyprobe immunostaining. Phosphodiesterase type 5 (PDE5), endothelial nitric oxide synthase (eNOS), and neuronal nitric oxide synthase (nNOS) mRNA expression were quantified by Real Time quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results., In BCN rats, we observed the onset of an overt condition of hypogonadism, characterized by reduced T plasma level, reduced ventral prostate weight, reduced testis function (including testis weight and number of Leydig cells), with an inadequate compensatory increase of luteinizing hormone. BCN induced massive penile hypoxia, decreased muscle/fiber ratio, nNOS, eNOS, PDE5 expression, increased sensitivity to the nitric oxide donor, sodium nitroprusside (SNP), and reduced the relaxant response to acetylcholine (Ach), as well as unresponsiveness to acute Tad dosing. In BCN rats, chronic Tad-administration normalizes penile oxygenation, smooth muscle loss, PDE5 expression, SNP sensitivity, and the responsiveness to the acute Tad administration. Chronic Tad treatment was ineffective in counteracting the reduction of nNOS and eNOS expression, along with Ach responsiveness. T supplementation, in combination with Tad, reverted some of the aforementioned alterations, restoring smooth muscle content, eNOS expression, as well as the relaxant response of penile strips to Ach, but not nNOS expression. Conclusion., BCN was associated with hypogonadism, probably of central origin. T supplementation in hypogonadal BCN rats ameliorates some aspects of BCN-induced ED, including collagenization of penile smooth muscle and endothelial dysfunction, except surgically induced altered nNOS expression.Vignozzi L, Filippi S, Morelli A, Marini M, Chavalmane A, Fibbi B, Silvestrini E, Mancina R, Carini M, Vannelli GB, Forti G, and Maggi M. Cavernous neurotomy in the rat is associated with the onset of an overt condition of hypogonadism. J Sex Med 2009;6:1270,1283. [source] ORIGINAL RESEARCH: Phosphodiesterase Type 5 Regulation in the Penile Corpora CavernosaTHE JOURNAL OF SEXUAL MEDICINE, Issue S3 2009Ching-Shwun Lin PhD ABSTRACT Introduction., Penile detumescence depends on the hydrolysis of cyclic guanosine monophosphate (cGMP) by phosphodiesterase type 5 (PDE5). It is hoped that a review of publications relevant to the regulation of PDE5 in the penis will be helpful to both scientists and clinicians who are interested in the sciences of erectile function/dysfunction. Aims., The aim of this article is to comprehensively review the mechanisms by which PDE5 activity and expression in the penis are regulated. All published studies relevant to PDE5 regulation in the penis or penile cells will be reviewed. Methods., Entrez (PubMed) was used to search for publications relevant to the topics of this review. Keywords used in the searches included vascular, cavernous, penis, smooth muscle, signaling molecules, erection, priapism, and PDE5. Articles that are dedicated to the study of erectile function/dysfunction were prioritized for citation. Results., Regulation of PDE5 can occur at both protein and gene levels. At protein level, PDE5 is activated by phosphorylation and/or allosteric cGMP binding. Deactivation is carried out by protein phosphatase 1 and thus linked to the Rho-kinase signaling pathway. Cleavage of PDE5 into an inactive form has been shown as carried out by caspase-3. At the gene level, PDE5 expression is regulated at two alternative promoters, PDE5A and PDE5A2, both of which are positively regulated by cyclic adenosine monophosphate and cGMP. Downregulation of PDE5 has been observed in the penis of castrated animals; however, proof of androgen regulation of PDE5 gene requires examination of the smooth muscle content. Hyperoxia and hypoxia, respectively, regulate PDE5 expression positively and negatively. Hypoxic downregulation of PDE5 is a possible mechanism for the development of priapism. Conclusions., PDE5 can be regulated at protein and gene levels. In the penis, changes of PDE5 activity have been linked to its phosphorylation status, and downregulation of PDE5 expression has been associated with hypoxia. Lin CS. PDE5 regulation in the penile corpora nervosa. J Sex Med 2009;6(suppl 3):203,209. [source] The Ontogenetic Expression Pattern of Type 5 Phosphodiesterase Correlates with Androgen Receptor Expression in Rat Corpora CavernosaTHE JOURNAL OF SEXUAL MEDICINE, Issue 2 2009Eleonora Carosa MD ABSTRACT Introduction., The mechanisms controlling erection in animals and in humans are mainly age-dependent. However, the ontogenesis of the biochemical machinery of erection is largely unknown. Aim., The aim of this article was to study the expression pattern of androgen receptor (AR) and the major cyclic guanosine monophosphate-hydrolyzing enzyme present in the corpora cavernosa, type 5 phosphodiesterase (PDE5), in the rat penis during development. Methods., AR and PDE5 expression was tested on ribonucleic acids (RNAs) and proteins extracted from the whole penis or from primary cultures of smooth muscle cells obtained from the corpora cavernosa of 3- (rCC3), 20- (rCC20), and 60- (rCC60) day-old rats. Rat corpus cavernosum cells were characterized by immunocytochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR). Main Outcome Measures., Expression of PDE5 and AR messenger RNA (mRNA) and protein have been measured by RT-PCR and Western blot, respectively. Results., A significant increase in PDE5 mRNA expression was observed with RT-PCR from prepuberty to adulthood (0.5 ± 0.06 vs. 1.6 ± 0.046 arbitrary units [a.u.]P = 0.049). This age-dependent increase was mirrored by the increase in PDE5 protein expression found when comparing neonatal to adult corpus cavernosum smooth muscle cells (1.5 ± 0.26 vs. 4.9 ± 0.59 a.u. P = 0.0038) and the further 1.6-fold increase from rCC20 to rCC60 (4.9 ± 0.59 vs. 8.0 ± 0.8 a.u. P = 0.0024). This is the first demonstration of the ontogenetic profile of PDE5 expression in corpus cavernosum smooth muscle. As it has been demonstrated that androgens control PDE5 expression and that PDE5 inhibitors need an optimal androgenic milieu to act perfectly on erection, the expression of AR protein in rat corpus cavernosum cells was then tested by Western blot. A 7.0-fold increase was observed in primary cultured cells from 3 to 60 days old (1.4 ± 0.38 vs. 9.8 ± 1.3 a.u. P = 0.0052). Conclusion., The increase in ARs during rat penile development parallels that of PDE5 RNA and protein, thus suggesting a positive effect of androgens on PDE5 expression. Carosa E, Rossi S, Giansante N, Gravina GL, Castri A, Dolci S, Botti F, Morelli A, Di Luigi L, Pepe M, Lenzi A, and Jannini EA. The ontogenetic expression pattern of type 5 phosphodiesterase correlates with androgen receptor expression in rat corpora cavernosa. J Sex Med 2009;6:388,396. [source] Chronic inhibition of nitric-oxide synthase induces hypertension and erectile dysfunction in the rat that is not reversed by sildenafilBJU INTERNATIONAL, Issue 1 2010Serap Gur Study Type , Aetiology (case control) Level of Evidence 3b OBJECTIVE To evaluate the effect of N(G)-nitro- l -arginine methyl ester (L-NAME)-induced hypertension (HT) on erectile function in the rat and determine if the phosphodiesterase (PDE)-5 inhibitor, sildenafil, can reverse the effects of nitric oxide (NO) deficiency, as HT is a risk factor for erectile dysfunction (ED) and the NO synthase (NOS) inhibitor L-NAME induces NO-deficient HT. MATERIALS AND METHODS Thirty-six adult Sprague-Dawley male rats were divided into three groups, i.e. a control, L-NAME-HT (40 mg/rat/day in the drinking water for 4 weeks), and sildenafil-treated L-NAME-HT (1.5 mg/rat/day sildenafil, by oral gavage concomitantly with L-NAME). The erectile response expressed as a ratio of intracavernosal pressure (ICP)/mean arterial pressure (MAP), evaluated after electrical stimulation of the right cavernous nerve. The isometric tension of corpus cavernosum smooth muscle (CCSM) was measured in organ-bath experiments. NOS expression was determined immunohistochemically for neuronal (n)NOS and by Western blot analysis for endothelial (e) and inducible (i) NOS protein. cGMP levels were evaluated by enzyme-linked immunosorbent assay. RESULTS The erectile response was diminished in the HT group. Nitrergic and endothelium-dependent relaxation was reduced, while the relaxation response to sodium nitroprusside and contractile response to phenylephrine were not altered in CCSM from L-NAME-treated rats. HT rats showed decreased expression of nNOS, whereas eNOS and iNOS protein expression was increased. Sildenafil partly restored endothelial and molecular changes in CCSM from HT rats, but did not reverse the decreased erectile response, even as cGMP levels returned to normal levels. CONCLUSIONS Sildenafil treatment did not correct the ED in L-NAME-treated HT rats. Under sustained high blood pressure, up-regulation of PDE5 expression failed to reverse the depletion of neuronal NO and/or impaired nNOS activity. However, endothelium-dependent relaxation was restored. Drug targeting of neuronal dysfunction might delay the onset of ED in HT. [source] | ||||||||||