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Introduction: Prior consensus meetings have addressed the relationship between phosphodiesterase type 5 (PDE5) inhibition and cardiac health. Given significant accumulation of new data in the past decade, a fourth consensus conference on this topic was convened in Pasadena, California, on March 10 and 11, 2023., Objectives: Our meeting aimed to update existing knowledge, assess current guidelines, and make recommendations for future research and practice in this area., Methods: An expert panel reviewed existing research and clinical practice guidelines., Results: Key findings and clinical recommendations are the following: First, erectile dysfunction (ED) is a risk marker and enhancer for cardiovascular (CV) disease. For men with ED and intermediate levels of CV risk, coronary artery calcium (CAC) computed tomography should be considered in addition to previous management algorithms. Second, sexual activity is generally safe for men with ED, although stress testing should still be considered for men with reduced exercise tolerance or ischemia. Third, the safety of PDE5 inhibitor use with concomitant medications was reviewed in depth, particularly concomitant use with nitrates or alpha-blockers. With rare exceptions, PDE5 inhibitors can be safely used in men being treated for hypertension, lower urinary tract symptoms and other common male disorders. Fourth, for men unresponsive to oral therapy or with absolute contraindications for PDE5 inhibitor administration, multiple treatment options can be selected. These were reviewed in depth with clinical recommendations. Fifth, evidence from retrospective studies points strongly toward cardioprotective effects of chronic PDE5-inhibitor use in men. Decreased rates of adverse cardiac outcomes in men taking PDE-5 inhibitors has been consistently reported from multiple studies. Sixth, recommendations were made regarding over-the-counter access and potential risks of dietary supplement adulteration. Seventh, although limited data exist in women, PDE5 inhibitors are generally safe and are being tested for use in multiple new indications., Conclusion: Studies support the overall cardiovascular safety of the PDE5 inhibitors. New indications and applications were reviewed in depth., (© The Author(s) 2024. Published by Oxford University Press on behalf of The International Society of Sexual Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The Princeton Consensus (Expert Panel) Conference is a multispecialty collaborative symposium dedicated to optimizing sexual function and preserving cardiovascular health. The Fourth Princeton Consensus Conference was convened on March 10-11, 2023, at the Huntington Medical Research Institutes in Pasadena, California. Princeton panels I to III addressed the clinical management of men with erectile dysfunction (ED) who also had cardiovascular disease. Thirteen years since Princeton III, Princeton IV builds on previous foundations in several key areas. Mounting evidence supports the need for providers to treat men with ED as being at risk for cardiac events until proven otherwise. Algorithms for the diagnosis and treatment of ED are updated with new recommendations for coronary artery calcium scoring for advanced cardiovascular risk stratification. Optimization of oral phosphodiesterase type 5 inhibitors in the treatment of men with ED and cardiovascular disease is thoroughly explored, including recent evidence of potential cardioprotective effects of these drugs., (Copyright © 2024 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.)

Background: In 1999, 1 year after the approval of the first oral phosphodiesterase type 5 (PDE5) inhibitor for the treatment of erectile dysfunction (ED), the first Princeton Consensus Conference was held to address the clinical management of men with ED who also had cardiovascular disease. These issues were readdressed in the second and third conferences. In the 13 years since the last Princeton Consensus Conference, the experience with PDE5 inhibitors is more robust, and recent new data have emerged regarding not only safety and drug-drug interactions, but also a potential cardioprotective effect of these drugs., Aim: In March 2023, an interdisciplinary group of scientists and practitioners met for the fourth Princeton Consensus Guidelines at the Huntington Medical Research Institutes in Pasadena, California, to readdress the cardiovascular workup of men presenting with ED as well as the approach to treatment of ED in men with known cardiovascular disease., Method: A series of lectures from experts in the field followed by Delphi-type discussions were developed to reach consensus., Outcomes: Consensus was reached regarding a number of issues related to erectile dysfunction and the interaction with cardiovascular health and phosphodiesterase-5 inhibitors., Results: An algorithm based on recent recommendations of the American College of Cardiology and American Heart Association, including the use of computed tomography coronary artery calcium scoring, was integrated into the evaluation of men presenting with ED. Additionally, the issue of nitrate use was further considered in an algorithm regarding the treatment of ED patients with coronary artery disease. Other topics included the psychological effect of ED and the benefits of treating it; the mechanism of action of the PDE5 inhibitors; drug-drug interactions; optimizing use of a PDE5 inhibitors; rare adverse events; potential cardiovascular benefits observed in recent retrospective studies; adulteration of dietary supplements with PDE5 inhibitors; the pros and cons of over-the-counter PDE5 inhibitors; non-PDE5 inhibitor therapy for ED including restorative therapies such as stem cells, platelet-rich plasma, and shock therapy; other non-PDE5 inhibitor therapies, including injection therapy and penile prostheses; the issue of safety and effectiveness of PDE5 inhibitors in women; and recommendations for future studies in the field of sexual dysfunction and PDE5 inhibitor use were discussed., Clinical Implications: Algorithms and tables were developed to help guide the clinician in dealing with the interaction of ED and cardiovascular risk and disease., Strengths and Limitations: Strengths include the expertise of the participants and consensus recommendations. Limitations included that participants were from the United States only for this particular meeting., Conclusion: The issue of the intersection between cardiovascular health and sexual health remains an important topic with new studies suggesting the cardiovascular safety of PDE5 inhibitors., (© The Author(s) 2023. Published by Oxford University Press on behalf of The International Society of Sexual Medicine.)

Human placental stem cells (PSCs) enhance histological and functional recovery in a rodent erectile dysfunction (ED) model. We tested the hypothesis that bioactive factors secreted by PSC (i.e., the secretome) mediate functional recovery and that acellular-conditioned media (CM) from PSC culture (PSC-CM) could be used independently to facilitate functional and histological recovery. To identify factors relative to efficacy of PSC, a comparison of CM from PSC and three additional human stem cell populations was performed. CM from human PSC, amniotic fluid stem cells (AFSCs), adipose-derived stem cells (ADSC), and human umbilical vein endothelial cells (HUVECs) was assayed using a semi-quantitative human cytokine antibody array. Male rats, after surgically created ED by neurovascular injury, were randomly divided into four groups: vehicle control (phosphate-buffered saline [PBS]), PSC, PSC-CM, and serum-free media control (SFM) as control. Functional data on intracorporal and mean arterial pressure were obtained, and histological architecture was examined 6 weeks after single injection. PSCs were found to secrete at least 27 cytokines and growth factors at a significantly higher level than the other three cell types. Either single injection of PSC-CM or PSC significantly improved erectile functional recovery and histological architecture compared with SFM or PBS. Injection of the secretome isolated from human PSC improves erectile functional recovery and histological structure in a rat model of neurovascular injury-induced ED. Further characterization of the unique protein expression within the PSC-CM may help to identify the potential for a novel injectable cell-free therapeutic for applicable patients., (© 2020 John Wiley & Sons, Ltd.)

Human stem cell therapy for type 2 diabetes/obesity (T2D/O) complications is performedwith stem cell autografts, exposed to the noxious T2D/O milieu, often with suboptimal results.We showed in the Obese Zucker (OZ) rat model of T2D/O that when their muscle-derived stemcells (MDSC) were from long-term T2D/O male rats, their repair ecacy for erectile dysfunctionwas impaired and were imprinted with abnormal gene- and miR-global transcriptional signatures(GTS). The damage was reproduced in vitro by short-term exposure of normal MDSC to dyslipidemicserum, causing altered miR-GTS, fat infiltration, apoptosis, impaired scratch healing, and myostatinoverexpression. Similar in vitro alterations occurred with their normal counterparts (ZF4-SC) fromthe T2D/O rat model for female stress urinary incontinence, and with ZL4-SC from non-T2D/O leanfemale rats. In the current work we studied the in vitro eects of cholesterol and Na palmitate aslipid factors on ZF4-SC and ZL4-SC. A damage partially resembling the one caused by the femaledyslipidemic serum was found, but diering between both lipid factors, so that each one appears tocontribute specifically to the stem cell damaging eects of dyslipidemic serum in vitro and T2D/Oin vivo, irrespective of gender. These results also confirm the miR-GTS biomarker value forMDSC damage.

Female stress urinary incontinence (FSUI) is prevalent in women with type 2 diabetes/obesity (T2D/O), and treatment is not optimal. Autograph stem cell therapy surprisingly has poor efficacy. In the male rat model of T2D/O, it was demonstrated that epigenetic changes, triggered by long-term exposure to the dyslipidemic milieu, led to abnormal global transcriptional signatures (GTS) of genes and microRNAs (miR), and impaired the repair capacity of muscle-derived stem cells (MDSC). This was mimicked in vitro by treatment of MDSC with dyslipidemic serum or lipid factors. The current study aimed to predict whether these changes also occur in stem cells from female 12 weeks old T2D/O rats, a model of FSUI. MDSCs from T2D/O (ZF4-SC) and normal female rats (ZL4-SC) were treated in vitro with either dyslipidemic serum (ZFS) from late T2D/O 24 weeks old female Zucker fatty (ZF) rats, or normal serum (ZLS) from 24 weeks old female Zucker lean (ZL) rats, for 4 days and subjected to assays for fat deposition, apoptosis, scratch closing, myostatin, interleukin-6, and miR-GTS. The dyslipidemic ZFS affected both female stem cells more severely than in the male MDSC, with some gender-specific differences in miR-GTS. The changes in miR-GTS and myostatin/interleukin-6 balance may predict in vivo noxious effects of the T2D/O milieu that might impair autograft stem cell (SC) therapy for FSUI, but this requires future studies.

Some trials have shown an overall benefit of low-intensity extracorporeal shockwave therapy (LI-ESWT) for erectile dysfunction, while others have been unable to find differences between LI-ESWT and sham treatment. In the absence of definitive evidence, patients should only be offered LI-ESWT in an investigational setting or on an off-label basis with a thorough understanding of the risks and benefits., (Copyright © 2019. Published by Elsevier B.V.)

Objective: To determine the long-term therapeutic effect amongst three human cell types on erectile function recovery in a rat model of dual neurovascular-injury erectile dysfunction (NVED)., Materials and Methods: A dual NVED model was established in athymic rats by crushing the bilateral cavernous nerves and ligating the bilateral internal pudendal neurovascular bundles. At the time of defect creation, three different types of human cell populations (2.5 × 10 6  cells/0.2 mL: umbilical vein endothelial cells, adipose-derived stem cells, and amniotic fluid-derived stem cells) were injected intracavernously into the penile tissue. Saline injection (0.2 mL) served as a control group. Erectile function and histomorphological analyses of penile tissues were assessed 12 weeks after defect creation and cell or saline injection., Results: The ratio of intracavernous pressure to mean arterial pressure (functional indicator) was significantly higher in the cell therapy groups compared to the saline-injected control group (P < 0.05). Immunofluorescence staining showed more cells expressing biomarkers of endothelial, smooth muscle, and nerve cells within the penile tissue in the cell therapy groups when compared to the control group., Conclusions: Cell therapy enhanced erectile function and ameliorated the histological changes 12 weeks after pelvic neurovascular injury in vivo, indicating that cell therapy may improve the long-term outcomes in neurogenic, myogenic and vascular tissue regeneration in the treatment of NVED., (© 2018 The Authors BJU International © 2018 BJU International Published by John Wiley & Sons Ltd.)

Multiple studies have evaluated the use of PDE5 inhibitors in penile rehabilitation following nerve-sparing prostatectomy. These studies have evaluated the use of various pharmacologic agents as well as various approaches to treatment (on-demand vs. rehabilitative). Most of these studies relied on self-reported outcomes to determine efficacy of the therapy which could allow response bias to affect their results. The aim of this study was to evaluate the effects of nightly sildenafil citrate therapy during penile rehabilitation, using nocturnal penile rigidity (RigiScan(™), Gotop Medical, Inc., St. Paul, MN, USA) in addition to the IIEF-EF. Patients with localized prostate cancer and normal erectile function prior to nsRP were randomized to take either nightly 50 mg sildenafil citrate or placebo starting the night following surgery. Both groups were allowed on-demand sildenafil citrate. Erectile function was evaluated at 2 weeks, 3, 6, 9 and 12 months post-operatively, with a final assessment made at 13 months, following a 1 month drug washout. At all time points, self-reported (IIEF-EF) and objective (RigiScan(™)) measures were obtained and evaluated. About 74 of 97 randomized patients completed the study. On completion, 40% of patients in each group had normal erectile function based on RigiScan(™) (p = 1.0). Additionally, no statistical differences were seen using the IIEF-EF domain (32.4% of placebo, 29% of treatment; p = 0.79). Multivariable analysis showed no significant differences in erectile function based on treatment intervention. Results did show that African-American men in this cohort were at higher risk for lower RigiScan(™) scores over time (OR: 0.48, p = 0.0399). This study demonstrates that nightly sildenafil citrate does not provide a therapeutic benefit for recovery of erectile function post-prostatectomy when compared to on-demand dosing using both self-reported as well as objective measures. Differences in objective recovery parameters based on patients' race/ethnicity warrant further investigation., (© 2015 American Society of Andrology and European Academy of Andrology.)

Introduction: Erectile dysfunction (ED) is the most common sexual disorder that men report to healthcare providers, and is the male sexual dysfunction that has been most investigated. Current treatments for ED focus on relieving the symptoms of ED and therefore tend to provide a temporary solution rather than a cure or reversing the cause. Recently, therapies based on stem cells (SCs) have had an increasing attention for their potential to restore erectile function. Preclinical studies showed that these cells might reverse the pathophysiological changes leading to ED, rather than treating the symptoms of ED. This review is intended to provide an overview of contemporary reports on the use of SCs to treat ED., Methods: We made an extensive search for reports on SC-based therapy for the management of ED, published in English between 1966 and 2013, using the search engines SciVerse-sciencedirect, SciVerse-scopus, Google Scholar and Pubmed, with the search terms 'erectile dysfunction', 'stem cells', 'multipotent stromal cells', 'adipose (tissue) derived stem cells', 'bone-marrow derived stem cells', 'animal model', 'diabetes', 'ageing', 'Peyronie's Disease' and 'cavernous nerve injury'., Results: Fifty-four papers were identified and contributed, either as an original research report or review thereof, to this review. Several preclinical studies addressed SC-based therapies for the recovery of erectile function caused by a variety of both chronic and acute conditions. Overall, these studies showed beneficial effects of SC therapy, while evidence on the mechanisms of action of SC therapy varied between studies. One clinical trial investigated the short-term effects of SC therapy in diabetic patients with ED. Two more clinical trials are currently recruiting patients., Conclusions: The rapidly expanding and highly promising body of preclinical work on SC-based medicine providing a potential cure for ED, rather than merely symptom relief, is indicative of the increasing interest in regenerative options for sexual medicine over the past decade. Clinical trials are currently recruiting patients to test the preclinical results in men with ED.

Peyronie's disease (PD) is caused by progressive fibrotic scarring of the tunica albuginea resulting in curvature or other deformities of the erect penis. The severity of penile curvature or other deformity may contribute to a man's inability to have intercourse (sexual disability), due to difficulty with penetration, partner pain or emotional stress. To determine whether the degree of curvature or type of penile deformity predicts sexual disability among men with PD. This cross-sectional analysis of consecutive men evaluated for PD at a single tertiary referral center used a PD-specific questionnaire to evaluate risk factors for sexual disability in men with PD, who did not have erectile dysfunction (ED). Multivariate logistic regression was used to determine the clinical predictors of sexual disability. Sexual disability as defined by the inability to have penetrative intercourse. A total of 202 men were evaluated and 88 men with ED were excluded. Sexual disability was associated with relationship problems, penile curvature and penile length loss in bivariate, but not multivariate analysis. We found that although many of the demographic, medical and sexual function domains were significant predictors of inability to have sex, the only significant predictor of sexual disability in multivariate analysis was curvature>60° (odds ratio 3.23 95%CI 1.08-9.67). PD can be sexually disabling in many men without ED. Severe penile curvature is a robust independent predictor of the ability to have intercourse. Other penile deformities fail to predict sexual disability. This is important for counseling patients with newly diagnosed PD and those who are considering medical or surgical intervention.

Inhibition of phosphodiesterase-5 (PDE5) is a well-known mechanism for the effective treatment of erectile dysfunction (ED). Androgen supplementation has also been prescribed for treating ED. However, it has been widely accepted that androgen can upregulate PDE5 expression, and thus creating a paradox in which a positive regulator of erectile function (androgen) could possibly increase the level of a negative regulator (PDE5). To solve this paradox, we conducted a systematic search of the PubMed and a non-systematic search of the Internet using PDE5, erectile, penis, testosterone and androgen as keywords. The retrieved papers were analyzed for data concerning the expression and regulation of PDE5 by androgens. Human and rat PDE5A gene sequences were retrieved from GenBank and computer-analyzed. The results showed that a putative androgen-response element (ARE) was reported in a study of human PDE5A gene promoter, and this prompted a separate study on whether androgen regulates PDE5 expression. The positive outcome in the latter study has since been cited in 17 review and editorial articles as the underlying mechanism for androgen's therapeutic effects on ED. In addition, five other research studies also reached the same conclusion. On the other hand, two independent studies on the genome-wide searches for androgen-regulated genes did not find PDE5A as a candidate. Sequence analysis conducted in this study also failed to find ARE in rat PDE5A gene. Two independent studies on Leydig cells also failed to find positive regulation of PDE5 expression by androgen. Two other studies found concomitant reduction of cavernous smooth muscle and PDE5 expression in castrated rats. One of these studies also found no effect of androgen on PDE5 expression in cultured cavernous smooth muscle cells. Thus, it appears that reduced PDE5 expression in castrated animals is due to reduced smooth muscle content and that PDE5A gene is not directly regulated by androgens.

In erectile dysfunction (ED) research, monocultures of cavernous endothelial cells (CECs) and smooth muscle cells (CSMCs) have been reported, but a CEC-CSMC coculture system is still lacking. In the present study, we wished to investigate the feasibility of setting up such a system and test whether it can be used for diabetic ED research. Cavernous tissues were obtained from patients undergoing surgery for penile prosthesis. CSMCs were isolated by explant culture and verified by calponin staining. CECs were isolated by binding to CD31 antibody, followed by magnetic capture. These CECs were nearly 100% pure endothelial cells as determined by flow cytometric analysis for endothelial markers CD31, vWF and eNOS. Functional analyses, that is, low-density lipoprotein (LDL) uptake and capillary tube formation, also confirmed their endothelial phenotype. When cocultured with CSMCs, CECs formed capillary-like structures, and based on the extent of this capillary-like network, it was determined that a ratio of 1:4 in cell number between CECs and CSMCs was better than ratios of 1:1 and 1:9. It was also found that direct contact between CECs and CSMCs was necessary and a coculture period of 3 weeks was optimal. Autologous CSMCs were better than allogeneic CSMCs, and fibroblasts were completely incompetent. When treated with high glucose (25 mM), the CEC-CSMC coculture expressed significantly lower level of CD31 but significantly higher level of collagen-IV (Col-IV), and the diameter of the capillaries increased significantly, when compared with normal glucose (5 mM)-treated cocultures. These data are consistent with previously observed changes in the cavernous tissues of diabetic patients and thus suggest that the coculture system could be utilized for diabetic ED research.

The intracavernous (i.c.) injection of stem cells (SCs) has been shown to improve erectile function in various erectile dysfunction (ED) animal models. However, the tissue distribution of the injected cells remains unknown. In this study we tracked i.c.-injected adipose-derived stem cells (ADSCs) in various tissues. Rat paratesticular fat was processed for ADSC isolation and culture. The animals were then subject to cavernous nerve (CN) crush injury or sham operation, followed by i.c. injection of 1 million autologous or allogeneic ADSCs that were labeled with 5-ethynyl-2-deoxyuridine (EdU). Another group of rats received i.c. injection of EdU-labeled allogeneic penile smooth muscle cells (PSMCs). At 2 and 7 days post injection, penises and femoral bone marrow were processed for histological analyses. Whole femoral bone marrows were also analyzed for EdU-positive cells by flow cytometry. The results show that ADSCs exited the penis within days of i.c. injection and migrated preferentially to bone marrow. Allogenicity did not affect the bone marrow appearance of ADSCs at either 2 or 7 days, whereas CN injury reduced the number of ADSCs in bone marrow significantly at 7 but not 2 days. The significance of these results in relation to SC therapy for ED is discussed.

There is strong evidence from multiple epidemological studies that lower urinary tract symptoms (LUTS) and erectile dysfunction (ED) are correlated, independent of age or comorbidities as diabetes or hypertension. Although a direct causal relationship is not established yet, four pathophysiological mechanisms can explain the relationship. These include alteration in nitric oxide bioavailability, α1-adrenergic receptor hyperactivity, pelvic atherosclerosis and sex hormones. This association has different clinical implications on the management of both disorders. Men seeking care for one condition should always be screened for complaints of the other condition. Sexual function should be assessed and discussed with the patient when choosing the appropriate management strategy for LUTS, as well as when evaluating the patient's response to treatment. Multiple large clinical trials have shown an improvement in LUTS after phosphodiesterase-5 (PDE5)-inhibitor treatment. PDE5 inhibitors show promise as a future treatment for LUTS, either in conjunction with existing therapies or as a primary treatment. There may be a potential therapeutic role for testosterone in LUTS treatment in cases of testosterone deficiency that needs to be investigated. Much further investigation is required, but it is evident that the association between LUTS and ED is fundamental for future therapies and possible preventative strategies.

Optoelectronic tweezers was used to manipulate human spermatozoa to determine whether their response to OET predicts sperm viability among non-motile sperm. We review the electro-physical basis for how live and dead human spermatozoa respond to OET. The maximal velocity that non-motile spermatozoa could be induced to move by attraction or repulsion to a moving OET field was measured. Viable sperm are attracted to OET fields and can be induced to move at an average maximal velocity of 8.8 ± 4.2 µm s(-1), while non-viable sperm are repelled to OET, and are induced to move at an average maximal velocity of -0.8 ± 1.0 µm s(-1). Manipulation of the sperm using OET does not appear to result in increased DNA fragmentation, making this a potential method by which to identify viable non-motile sperm for assisted reproductive technologies.

Peyronie's disease is a fibrotic disorder of the tunica albuginea of the penis resulting in varying degrees of penile curvature and sexual dysfunction. Diagnosis of the disorder is made by detailed sexual history and focused physical examination. A wide range of medical treatments has been employed to treat the disorder. Verapamil treatment administered by intraplaque injection is supported by generally consistent randomized controlled trials (RCT). Some RCT evidence exists to support the use of colchicine, potaba, L-carnitine and liposomal superoxide dismutase. Future studies of medical efficacy should focus on improving RCT design, implementation and results reporting to improve the quality of evidence generated by each study. The surgical treatment of Peyronie's disease is a viable and recommended alternative for men with compromised sexual function due to severe curvature or lesions causing penile instability. The choice of corrective procedure should be tailored to each patient after a detailed evaluation of disease severity and sexual function.

Introduction: Peyronie's disease (PD) occurs in 3-9% of all men. Little is known regarding the specific psychological or emotional disruptions to sexuality associated with PD., Aim: Our primary aim was to identify risk factors associated with psychosocial difficulties in men with PD., Methods: This cross-sectional study enrolled patients from a single clinical practice. Detailed medical histories, physical examinations, and a PD-specific questionnaire were used to define clinical characteristics. Odds ratios (ORs) were used as a measure of association., Main Outcome Measures: Emotional and relationship problems were determined by "yes" or "no" answers to two specific questions., Results: The mean age of all PD patients (N = 245) was 54.4 years (range 19.4-75.6); 62% were married, and 59% presented within 2 years of disease onset. The overall prevalence of emotional and relationship problems attributable to PD was 81% and 54%, respectively. Among men who had relationship problems, the prevalence of emotional problems was 93%. In men with emotional problems due to PD, relationship issues were observed in 62%. Multivariable analysis revealed that emotional difficulties (OR 6.9, P < 0.001) and ability to have intercourse (OR 0.4, P = 0.004) were independently associated with relationship problems. Relationship problems (OR 8.0, P < 0.001) and loss of penile length (OR 2.7, P = 0.02) were significant independent predictors of emotional problems after adjustment for the ability to maintain erections, low libido, and penile pain., Conclusions: Among men with PD, there is a very high prevalence of emotional and relationship problems. Loss of penile length and inability to have intercourse are strong predictors of these problems and as such make ideal targets for intervention. Medical and surgical therapies may enhance quality of life through their ability to improve sexual function. Further research will characterize the ways in which individual symptoms affect emotional and psychological well-being.

Introduction: There are no validated scales for assessing the psychosocial impact of Peyronie's disease (PD), which affects approximately 5-10% of men over age 50., Aim: To develop a psychometrically valid outcome measure for assessing psychosocial and sexual consequences of PD. To conduct a qualitative study of men with PD and age-matched controls, and design a new patient-reported outcome measure of PD., Methods: An expert advisory panel identified relevant topics and conceptual areas to be addressed based on clinical experience and literature reviews. A conceptual model was developed to serve as a discussion guide for qualitative interviews with geographically and ethnically diverse PD subjects and controls. Interviews were conducted in a focus-group format by a trained interviewer and were recorded and transcribed for qualitative analysis according to grounded theory concepts., Main Outcome Measure: Focus-group interviews., Results: Focus-group interviews were conducted with 64 men (28 PD patients, 36 controls) in 13 separate focus groups over a 3-month period. Blinded analysis of the interview transcripts identified four core domains: (i) physical appearance and self-image; (ii) sexual function and performance; (iii) PD-related pain and discomfort; and (iv) social stigmatization and isolation. Based on feedback from participants and experts, a new outcome questionnaire was developed to assess core domain responses in a structured, self-report format., Conclusions: This qualitative study helped to refine and broaden the focus of the conceptual model for further assessment. It also confirmed that PD has a major impact on sexual and psychological function in these patients.

Endothelial dysfunction (EtD) has emerged as a critical master pathway in the pathogenesis of both vascular disease and erectile dysfunction (ED). Drugs that have been developed for vascular diseases and/or found to have beneficial endothelial effects may be helpful in the management of ED. In this manuscript we summarize the current state of the art with respect to endothelial active drugs and discuss the evidence supporting their use in the management of ED. Pubmed query for the terms Endothelial dysfunction, erectile dysfunction, pharmaceuticals, "endothelium", "function", "pharmaceutical", "eNOS", "erectile dysfunction" and "erectile function" was conducted. Relevant articles were reviewed and summarized. A variety of cardiovascular medications have mechanisms of action that involve the endothelium. Examples include HMG-CoA Reductase inhibitors ("statins"), Angiotensin Converting Enzyme Inhibitors (ACEI), Angiotensin Receptor blockers (ARB), Endothelin Receptor Antagonists (ERA), certain beta blockers, and some oral hypoglycemics. Some of these drugs have been found to improve penile erection, although an endothelium dependent mechanism has not been conclusively demonstrated in all studies. Drugs that improve endothelial function in the cavernous arteries and the erectile tissues of the corpora cavernosa hold great promise in treating or at least minimizing the vascular damage that contributes to ED. ACEI and ARB appear to hold great promise in this regard, while statins and oral hypoglycemics may play a potentially useful role as adjunctive therapy for ED. Improvements in endothelial function may help reverse ED in some cases, which would be a marked improvement over management with currently available "on demand" ED therapies.

Purpose: The Cross-National Survey on Men's Health Issues was a population based, international survey of men using the health care systems of participating countries. The prevalence of erectile dysfunction (ED) and its correlation with patient age, overall health and comorbidities were assessed., Materials and Methods: Men who were 20 to 75 years old in the United States, Germany, United Kingdom, France, Italy and Spain were recruited to participate in the study. During visits to physician offices participants completed a screening questionnaire about their overall health, and problems with prostate, urination and penile erection. Men who reported ED completed a followup questionnaire., Results: A cohort of 28,691 men completed the screening questionnaire and provided their age. Respondents in the oldest age group (70 to 75 years) were at 14-fold higher relative risk for ED than respondents in the youngest age group (20 to 29 years). ED correlated positively with poor overall health, and prostate and urinary problems. The prevalence of comorbid conditions increased with ED severity. Only a small percent of men with ED (2% to 8%) were using nitrates for comorbid cardiac disorders. Approximately 10% to 20% of men were on beta-blockers., Conclusions: The results of this survey are consistent with those of other population based reports showing a high correlation between ED prevalence and patient age, and ED and lower urinary tract symptoms. The prevalence of comorbidities, such as vascular conditions, increased with ED severity, which may indicate that ED is a prognostic marker of overall health and an important medical condition.

Transforming growth factor beta (TGF-beta) has been implicated in many chronic fibrotic conditions such as pulmonary and hepatic fibrosis. Inhibition of TGF-beta activity can prevent the development of chronic hepatitis and mesangial proliferative glomerulonephritis. We postulated that TGF-beta might play a role in the pathogenesis of Peyronie's disease (a localized connective tissue disorder that primarily affects the tunica albuginea and adjacent erectile tissue of the penis). Tissue from the tunica albuginea of thirty-five Peyronie's patients (study group) and from eight patients without Peyronie's disease who had undergone penile prosthesis surgery for organic impotence (control group) were subjected to histological study using Hart and Trichrome stains and Western blotting for the detection of TGF-beta protein expression. TGF-beta1 protein expression was detected in 30 patients (85.7%), while only 8 (22.8%) and 6 (17.1%) patients showed TGF-beta2 and TGF-beta3 protein expression, respectively. All tissue from Peyronie's patients showed a variety of histological changes of the tunica, ranging from chronic inflammatory cellular infiltration to complete calcification and ossification of the tissues. The most prominent changes observed were focal or diffused ellastosis, fenestration, and disorganization of the collagen bundles. One patient in the control group showed fibrosis of the tunica albuginea and protein expression of TGF-beta1 and TGF-beta2. This patient had undergone surgery for the revision of his prosthesis twice. However, the other seven patients showed normal histologic patterns of the tunica albuginea and no protein expression for TGF-beta1, TGF-beta2, or TGF-beta3. In conclusion, TGF-beta1 protein expression is significantly associated with Peyronie's disease and may be a direct cause for its development. This finding may be of help in the prevention and treatment of this disease.

The purpose of this work was to study the effect of insulin-like growth factor 1 (IGF-1) and its binding protein (IGFBP-3) on the recovery of erectile function in a rat model for neurogenic impotence. In all, 28 male Sprague-Dawley rats were divided into four groups: seven underwent a sham operation; seven underwent bilateral cavernous nerve freezing (control group); seven underwent bilateral cavernous nerve freezing followed by intraperitoneal injection of IGF-1; and seven underwent bilateral cavernous nerve freezing followed by intraperitoneal injection of IGFBP-3. Erectile response was assessed by cavernous nerve electrostimulation at 3 months, and samples of penile tissue were evaluated histochemically for nitric oxide synthase (NOS)-containing fibers. In the sham and IGF-1 group, there were significantly higher maximal intracavernous pressures compared to the IGFBP-3 complex and the control group. Correspondingly in the cavernosum, there were significantly more NOS-containing nerve fibers in the sham and IGF-1 groups. In conclusion, administration of IGF-1 can facilitate the regeneration of NOS-containing nerve fibers in penile tissue and enhance the recovery of erectile function after bilateral cavernous nerve cryoablation. The reverse effect was noted with the IGFBP-3 complex injection.

Trauma to the cavernous nerve is a known cause of erectile dysfunction, with lengthy and often incomplete recovery. Using rat models, we have previously shown that injury to the cavernous nerves or ligation of pudendal arteries causes a significant decrease of neuronal nitric oxide synthase (nNOS) in the dorsal nerve of the penis and intracavernosal tissue as well as loss of erectile response to neurostimulation. Intracavernous injection of vascular endothelial growth factor or brain-derived neurotrophic factor facilitates the recovery of nNOS and erectile function. Studies are underway to elucidate the molecular mechanism of cavernous nerve regeneration and the potential of using growth factors to enhance the recovery of erectile function in patients after radical pelvic surgery. International Journal of Impotence Research (2004) 16, S38-S39. doi:10.1038/sj.ijir.3901214

Despite availability of outcome measures and scales for assessing erectile dysfunction (ED) treatment efficacy, guidelines are not available for assessing broader therapeutic outcomes or defining treatment failure in ED. An International Consensus Advisory Panel was convened to develop guidelines, definitions and a new algorithm for evaluating treatment effectiveness in ED. These new guidelines are recommended for use in both research and clinical practice. A multidisciplinary, international panel, consisting of 11 senior researchers and clinicians, was convened to address pertinent issues concerning therapeutic outcome assessment for ED. The panel utilized a modified Delphi method of consensus development and proposed a new model for outcomes assessment. This model is inherently testable, using existing instruments and current methods of assessment. Following a comprehensive literature review and discussion, the Panel recommended adoption of a new treatment effectiveness conceptual framework or theoretical model for assessing therapeutic outcomes in ED. Treatment effectiveness is presumed to be a combined function of two other factors, treatment response and treatment satisfaction. Treatment response is based on the combined assessment of efficacy and tolerability, and treatment satisfaction on the combined assessment of patient and partner satisfaction. Taken together, these two domains define an overall domain of treatment effectiveness. This therapeutic index would be derived by independently assessing treatment efficacy and satisfaction by means of event logs, questionnaires or the more typical patient interview methods. In conclusion, the Ad Hoc Advisory Consensus Panel recommends adoption of a new framework or conceptual model for conducting ED outcome trials or clinical research. The concept of 'treatment effectiveness' is proposed as a new 'umbrella concept' or distal outcome to be evaluated.

The physiology of erection has received intense clinical and basic research scrutiny over the past two decades. This massive effort has led to a much clearer understanding of the macroscopic aspects of erection as well as identification of the prominent features of the etiology of erectile dysfunction (ED). However, it is clear that the devil is in the details of the erectile process. Therefore, to truly understand the precise mechanistic basis for erection and ED, much more still must be learned about how the biochemical cascades in the corporal smooth muscle cells are integrated to produce a normal erection, or how they are altered to result in ED. The ultimate goal of these basic research and clinical efforts will be to provide a rational scientific basis for mechanism-based, patient-specific therapies for ED. This article reviews fundamental aspects of the physiology of erection and summarizes the most recent information available concerning the putative biochemical correlates of these physiologic events., (Copyright 2004 Humana Press Inc.)

We hypothesize that downregulation of sex hormone receptors (androgen, estrogen and progesterone receptors) is involved in aging-related erectile dysfunction. To test this hypothesis, we investigated the expression of sex hormone receptors in penile crura of aging rats. A total of 40 rats were divided into four groups based on age (6, 12, 18 and 24 months), and the erectile function was analyzed by the measurement of intracavernous pressure. Gene and protein expressions of sex hormone receptors were analyzed by RT-PCR and immunostaining, respectively. The mean intracavernous pressures of 6-, 12-, 18- and 24-month-old rats were 110.1, 89.6, 73.5 and 42.7 cm H(2)O, respectively. Gene and protein expressions for androgen receptor, estrogen receptor-beta and progesterone receptor were present in similar levels in 6-, 12- and 18-month-old rat crura, but significantly lower or absent in 24-month-old crura. This is the first study to demonstrate that downregulation of sex hormone receptors in aging rat crura is associated with erectile dysfunction.

Objective: To test the effect of wogonin on cellular proliferation and expression of monocyte chemoattractant protein 1 (MCP-1) in cells derived from normal and diseased tunica albuginea (TA), as related to Peyronie's disease (PD)., Materials and Methods: Cells with characteristics of fibroblasts were isolated from three tissue sources. Those from the plaque of patients with PD were designated as P cells, those from the adjacent, normal-appearing tissue as C cells, and those from the TA of patients without PD as N cells. These cells were treated with wogonin at doses of 0, 10, 20 and 40 micromol/L for 24 h or treated at a fixed dose of 40 micromol/L for 1, 8 and 24 h. Cell proliferation was assayed with a commercial kit, MCP-1 mRNA expression by reverse transcription-polymerase chain reaction, and secreted MCP-1 by enzyme-linked immunosorbent assay., Results: Wogonin suppressed cell proliferation in a dose-dependent manner; the effect was more pronounced against P cells at 8 and 24 h. Wogonin down-regulated MCP-1 mRNA expression, especially in P cells. Wogonin suppressed the level of secreted MCP-1 by 59-88%. P cells, which secreted far more MCP-1 than N and C cells at 1 h, were suppressed by 88%. C cells were the least suppressed at all three times., Conclusions: Wogonin suppressed the proliferation, the expression of MCP-1 mRNA, and the expression of secreted MCP-1 in TA-derived cells. In most cases, the effect of wogonin was greatest against cells derived from the plaque. Wogonin appears to be a worthy candidate for preclinical trials in men with PD.

Priapism is a condition first described by Tripe in 1845. It has been defined as a pathological condition of penile erection that persists beyond or is unrelated to sexual stimulation. Two variants of priapism have been well described. The ischemic priapism (also known as low-flow priapism) and nonischemic priapism (or high flow priapism) have unique and distinct causes. It is important to distinguish these two conditions as the treatment for each is different. This review will focus on the two types of priapism and the appropriate diagnostic work-up for each. As well, the medical and surgical treatment options for these two conditions will be described in detail. A third entity known as stuttering priapism will also be discussed as will its unique treatment alternatives.

Objective: To investigate the feasibility of using a ganglial culture system to screen various growth factors as potential therapeutic agents for pelvic nerve injuries., Materials and Methods: The major pelvic ganglia (MPG) were isolated from male rats and attached to culture dishes with the aid of Matrigel (Becton Dickinson, Mountain View, CA, USA). Alternatively, the dorso-caudal region (DCR) of MPG, from which the cavernous nerves originate, was dissected and then attached to a Matrigel-coated coverslip. The MPG or DCR was cultured in serum-free medium supplemented with phosphate-buffered saline (PBS, control), 50 ng/mL of vascular endothelial growth factor (VEGF), 20 ng/mL of a neurotrophin (BDNF, NT3, or NT4), or combinations of these growth factors. After 2 days of incubation, the ganglial tissues with their outgrowing nerve fibres were stained for the expression of NADPH-diaphorase, tyrosine hydroxylase (TH) and acetylcholinesterase (AChE). The length and staining intensity of nerve fibres were analysed., Results: The outgrowing fibres were significantly longer in MPG treated with any of the four tested growth factors than in PBS-treated MPG. The combination of VEGF and NT3 induced the best fibre growth. Improvements to the culturing conditions allowed a histological examination of the outgrowing fibres for the expression of nitric oxide synthase (NOS), TH and AChE. VEGF and BDNF were equally capable of inducing NOS- and TH-expressing fibres. BDNF was much weaker than VEGF for inducing AChE-expressing fibres., Conclusions: This improved culturing system is potentially useful for screening nerve-regenerating factors; VEGF had neurotrophic effects comparable with BDNF, NT3, or NT4.

Objective: To test the hypothesis that an intracavernosal injection with brain-derived neurotrophin factor (BDNF) and vascular endothelial growth factor (VEGF) can facilitate nerve regeneration and recovery of erectile function after cavernosal nerve injury., Materials and Methods: The study included 25 Sprague-Dawley rats; four had a sham operation, seven bilateral nerve crushing with no further intervention, and 14 bilateral nerve crushing with either an immediate (seven) or delayed for 1 month (seven) intracavernosal injection with BDNF+VEGF. Erectile function was assessed by cavernosal nerve electrostimulation at 3 months, and neural regeneration by NADPH-diaphorase staining and tyrosine hydroxylase (TH) staining of penile tissue and major pelvic ganglia (MPG)., Results: After nerve crushing, the functional evaluation at 3 months showed a lower mean (SD) intracavernosal pressure (ICP) with cavernosal nerve stimulation, at 33.9 (15.3) cmH2O, than in the sham group, at 107.8 (18.1) cmH2O. With an immediate injection with BDNF+VEGF the ICP was significantly higher than in the controls, at 67.8 (38.5) cmH2O. Even delayed injection with BDNF+VEGF improved the ICP, to 78.0 (21.8) cmH2O. Histological analysis of specimens stained for NADPH and TH showed a significant change in the morphology of terminal branches of the cavernosal and dorsal nerves, and the staining quality of the neurones in the MPG. The number of positively stained nerve fibres tended to revert to normal after treatment with BDNF+VEGF., Conclusion: An intracavernosal injection with BDNF+VEGF appears to both prevent degeneration and facilitate regeneration of neurones containing neuronal nitric oxide synthase in the MPG, dorsal nerve and intracavernosal tissue. Therefore it might have therapeutic potential for enhancing the recovery of erectile function after radical pelvic surgery.

Inhibition of cGMP-specific phosphodiesterase type 5 (PDE5) has been shown to improve penile erection in patients with erectile dysfunction. We have reported previously the cloning of three PDE5 isoforms from human penile tissues. Here we report the cloning of two PDE5 isoforms from rat penile tissues. The similarity between rat and human PDE5A1-specific sequences were 68 and 88% at the nucleotide and amino-acid levels, respectively. Like the bovine and canine PDE5A1 sequences, the rat PDE5A1 sequence lacks the polyglutamine tract that appears to be unique to the human PDE5A1 sequence. The similarity between rat and human PDE5A2-specific sequences were 64 and 100% at the nucleotide and amino-acid levels, respectively. The equivalent of human PDE5A3-specific sequence was identified in the rat PDE5A gene; however, repeated efforts to clone the putative rat PDE5A3 isoform were not successful. Expression of PDE5A1 and A2 mRNA in various tissues was examined by Northern blotting and reverse transcription-polymerase chain reaction. Results from the two experimental procedures were largely in good agreement and indicated that PDE5A1 and A2 mRNA were expressed in a tissue-specific manner with PDE5A2 being the dominant isoform. International Journal of Impotence Research (2003) 15, 129-136. doi:10.1038/sj.ijir.3900983

Purpose: To our knowledge the relationship between the underlying etiology of erectile dysfunction and its impact on health related quality of life has not been studied. Such a study is important for men with prostate cancer, as the potential negative quality of life impact of erectile dysfunction may affect clinical decision making in newly diagnosed disease. We compare health related quality of life in impotent men with prostate cancer to that of impotent men without prostate cancer using the Exploratory and Comprehensive Evaluation of Erectile Dysfunction (ExCEED, TAP Pharmaceutical Products, Inc., Lake Forest, Illinois) data base, which is a multicenter, observational disease registry of men with erectile dysfunction., Materials and Methods: The cohort included 168 men in ExCEED who had baseline health related quality of life measurement. Of these men 47 reported a history of prostate cancer while 121 did not. Appropriate univariate and multivariate analyses were performed comparing health related quality of life outcomes between impotent men with and without prostate cancer., Results: Men with erectile dysfunction and prostate cancer had worse sexual self-efficacy, erectile function, intercourse satisfaction and orgasmic function than those with erectile dysfunction without prostate cancer (all p <0.001). However, men with erectile dysfunction and prostate cancer experienced less psychological impact of erectile dysfunction on sexual experience (p = 0.05) and emotional life (p = 0.03) than those with erectile dysfunction without prostate cancer. The findings regarding the psychological impact of erectile dysfunction persisted in multivariate linear regression models., Conclusions: Men with erectile dysfunction and prostate cancer appear to have better disease specific health related quality of life than those with erectile dysfunction and no history of prostate cancer. This finding has important ramifications for clinicians when counseling patients newly diagnosed with prostate cancer and also when treating patients who present with erectile dysfunction of various etiologies.

Penile veno-occlusive dysfunction (venogenic erectile dysfunction) is a common cause of erectile dysfunction (ED). We investigated whether vascular endothelial growth factor (VEGF) can be used to prevent and reverse venogenic ED in a rat model. Pharmacological cavernosometry was developed and validated using adult male rats with either arteriogenic or venogenic ED. Castrated animals were treated with intracavernous VEGF as either a recombinant protein (C+VEGF) or adeno-associated virus (AAV)-mediated VEGF gene therapy (C+VEGF gene) in an attempt to prevent the development of venogenic ED. Other animal groups received testosterone replacement (C+testosterone) or intracavernous AAV-LacZ gene (C+LacZ). Animals with documented venogenic ED were treated with intracavernous VEGF in an attempt to reverse their ED. Functional analysis (pharmacological infusion cavernosometry) was performed following treatment. Penile specimens were harvested for immunohistochemistry and electron microscopic evaluation. Castrated rats showed a decrease in papaverine-induced intracavernous pressure and an increase in maintenance and drop rates during pharmacological cavernosometry. These changes were prevented by systemic testosterone and intracavernous VEGF or AAV-VEGF therapy. Moreover, intracavernous VEGF was able to reverse the venogenic ED produced by castration. The quantity of penile smooth muscle detected by alpha actin staining decreased after castration but not in the C+T, C+VEGF, or C+VEGF gene groups. Transmission electron microscopy revealed atrophy of penile smooth muscle cells and nerves in the castrated rats. In VEGF-treated rats, regeneration of smooth muscle and nerves as well as endothelial cell hypertrophy and hyperplasia were the prominent features. In our animal model, systemic testosterone replacement or intracavernous VEGF (protein and VEGF gene) prevented the veno-occlusive dysfunction in castrated animals. In rats with established venous leakage, VEGF treatment reversed the cavernosometric findings of leakage. Intracavernous injection of either VEGF protein or VEGF gene may be a preferred therapy to preserve erectile function in patients in whom testosterone therapy is contraindicated.

Peyronie's disease is a medically and surgically challenging condition to manage. Most surgical techniques to correct the penile deformity often shorten the penis and do not address the issue of hourglass deformity when present. We describe our indications, rationale and technique for the use of a saphenous vein graft after a curvature correcting plaque incision. In reviewing multiple series, this approach yields similar results-incidence of residual curvature: 4-20%, decreased potency: 5-20%, penile shortening: 17-40%. While harvesting the vein would require a second incision, the use of autologous vein appears to be associated with the least amount of intracavernosal fibrosis. We propose that saphenous vein is currently the best material available for tunical patching. The technique and results of circular venous grafting for patients with severe penile shortening secondary to Peyronie's disease is also discussed.

Purpose: Neurogenic impotence is a common complication after radical pelvic surgery, irradiation or perineal trauma. Neuronal transplantation is a new frontier for treating neurological disorders. We investigated whether the major pelvic ganglion can survive and become functional after being implanted into the corpus cavernosum in adult rats., Materials and Methods: Adult male rats (13) were divided into 3 groups and sacrificed at 3 time points, namely 30 (4), 60 (5) and 90 (4) days. All rats underwent excision of the right major pelvic ganglion and left cavernous nerve. The right ganglion was implanted into the right crus of the penis. Electrostimulation was applied to the left major pelvic ganglion and cavernous nerve (1.5 mA.) and right crus (10 mA.) at sacrifice. The crural region and left ganglion were then excised for immunostaining of neuronal nitric oxide synthase (nNOS), protein gene product 9.5 and growth associated protein 43. Image analysis was used to calculate the area stained in pixels. Electron microscopy of the implanted area was performed to assess neuronal survival., Results: Although the degree varied, all neuronal implants survived after transplantation. The response to electrostimulation was insufficient to produce erection. No difference was noted among the areas of nNOS staining when specimens from the 3 time points were compared. The area of expression of nNOS, protein gene product 9.5 and growth associated protein 43 was larger in the implanted area than in the surrounding cavernous tissue. Under electron microscopy most surviving implants showed normal ultrastructure, although areas of fibrotic replacement were seen in several implants., Conclusions: Our results show that the autotransplanted major pelvic ganglion expresses nNOS, protein gene product 9.5 and growth associated protein 43, and survived up to 90 days after implantation into the corpus cavernosum. Further studies with fetal neuronal tissue seem warranted.

Objective: To identify genes that are affected by vascular endothelial growth factor (VEGF), as an intracavernosal injection with VEGF improved the recovery of erectile function in a rat model of arteriogenic impotence, specifically examining the three nitric oxide synthase (NOS) genes, nNOS, eNOS, and iNOS., Materials and Methods: Male rats had their pudendal arteries ligated or underwent a sham operation. They were then treated by an intracavernosal injection with 4 microg of VEGF in phosphate-buffered saline (PBS) or PBS alone. At 6 and 24 h after treatment electrostimulation was applied to the cavernosal nerve and the intracorporal pressure measured. The erectile tissue was then harvested for RNA isolation and cryo-sectioning. The isolated RNA was used for microarray and reverse transcription-polymerase chain reaction (RT-PCR) analyses, and the tissue sections for immunohistochemical analysis., Results: Microarray analysis detected nNOS, eNOS and iNOS at very low expression levels in PBS-treated rats; expression levels were higher for eNOS and iNOS in all VEGF-treated rats. These results were further confirmed by RT-PCR analysis. Immunohistochemical analysis identified the cavernosal endothelium and smooth muscle as the tissue types where eNOS and iNOS were up-regulated, respectively., Conclusions: This is the first report of the induction of both eNOS and iNOS in the penis after intracavernosal VEGF. These events may help support a significant recovery of erectile function after interrupting the blood supply to the penis.

Objective: To investigate protein kinase G-I (PKG-I) expression and activation in cavernosal smooth muscle cells (CSMC) of young and old rats., Materials and Methods: PKG-I expression in rat penis was examined by immunohistochemical staining, reverse transcription-polymerase chain reaction, and Western blot analysis. CSMC isolated from young (16-week-old) and old (28-month-old) rats were grown as monolayer cell cultures and treated with different dosages of cAMP or cGMP for different periods. Their proteins were then analysed for the expression of vasodilator-stimulated phosphoprotein (VASP), phosphorylated VASP (at serine 239), PKG-I, and protein kinase A (PKA)., Results: PKG-I expression was detected in the vascular and CSMC of the rat penis. There was little or no difference in the level of PKG-I expression between young and old rats. Treatment of CSMC with different dosages of cAMP or cGMP did not change the expression levels of VASP throughout the entire test period (up to 24 h). In contrast, the level of VASP phosphorylation at S239, i.e. the level of PKG-I activation, depended on the dosages of cAMP and cGMP and on the duration of treatment. Prolonged treatment (24 h) with either cAMP or cGMP resulted in down-regulation of both PKG-I and PKA. While cAMP and cGMP produced very similar results in nearly every aspect, there was a difference in one test, in which cGMP produced much less activated PKG-I than cAMP in the CSMC of 28-month-old-rats., Conclusions: For the first time we provide evidence for PKG-I activation in CSMC. Both cAMP and cGMP were capable of activating PKG-I in CSMC. Age seemed to compromise the ability of PKG-I in response to cGMP.

Sildenafil improves erectile function by inhibiting the cGMP-catalytic activity of phosphodiesterase type V (PDE5). We used rapid amplification of cDNA Ends-polymerase chain reaction (RACE-PCR) to isolate three PDE5 isoforms from human corpus cavernosum. Semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis on eight human cavernous tissue samples showed that all samples expressed the PDE5A1 at a lower level than the PDE5A2 isoform. Five samples expressed the PDE5A3 isoform at various levels while the other three did not. Analysis on non-penile tissues showed that all tissues expressed the A1 and A2 isoforms while only those that have substantial amounts of smooth muscle expressed the A3 isoform. Cloning and sequencing of the PDE5A gene showed that the isoform-specific 5'-ends of the PDE5 mRNAs are encoded from three alternative first exons arranged in the order of A1-A3-A2. Promoter activities were detected upstream from the A1-specific exon and in the intron preceding the A2-specific exon. The upstream PDE5A promoter is expected to direct the expression of all three PDE5 isoforms while the intronic PDE5A2 promoter only the A2 isoform. Both promoters were upregulated by increasing concentrations of either cAMP or cGMP. Several transcription factor AP2 and Sp1-binding sequences identified in the promoters are likely to be the mediators of cAMP/cGMP-responsiveness.

Penile erection is a neurovascular event modulated by psyche and hormones. Erectile dysfunction (ED) has been classified as psychogenic, arteriogenic, neurogenic, endocrinologic, and cavernosal, based on the organs that are involved in penile erection. Among these types, neurogenic ED may be the most common, probably because a deficiency of neurotransmitters is the final common pathway in many diseases and conditions. This review discusses the physiology, pathophysiology, diagnosis, and treatment of erectile function and dysfunction, as well as strategies for future research.

Protein kinase G-I (PKG-I) activation is essential for vascular relaxation; however, its quantitative analysis in intact cells has been difficult. To overcome this difficulty, a monoclonal antibody, VASP-16C2, was recently developed that detects phosphorylated serine residue 239 of vasodilator-stimulated phosphoprotein (VASP), a substrate of PKG-I. In this study, we used this antibody to examine (i) possible functional differences between the alpha and beta isoforms of PKG-I, (ii) ability of cAMP to activate PKG-I, as compared to cGMP, the principal PKG-I-activating cyclic nucleotide, and (iii) time course and levels of PKG-I activation in vascular smooth muscle cells (VSMC) of young and old rats. We created COS-7 cell clones that overexpressed PKG-Ialpha or PKG-Ibeta, treated them with cAMP or cGMP, and analyzed their cell lysates for reactivity with VASP-16C2. The results showed that PKG-Ialpha phosphorylated VASP at a higher level than PKG-Ibeta, and cAMP was slightly weaker than cGMP in PKG-I activation. VSMC of young rats responded to cAMP or cGMP stimulation in a dose-dependent manner with increasing levels of PKG-I activation. The response was detected within 10 min and continued for at least 24 h. In contrast, VSMC of old rats showed no PKG-I activation during the first hour of cAMP or cGMP stimulation and, at 24 h these cells showed only low-level PKG-I activation. We propose that the reduced PKG-I activation may explain why vascular relaxation is decreased in older individuals., (Copyright 2001 Academic Press.)

Purpose: Because decreased trabecular smooth muscle content is reportedly associated with vasculogenic impotence in men, we performed a rodent study to investigate the effect of aging on trabecular smooth muscle content and caveolin-1 protein expression in penile smooth muscle cells., Materials and Methods: In 6 young (age 3 months) and 6 old (age 24 months) rats erectile function was evaluated by cavernous nerve stimulation. At sacrifice penile tissue samples were collected for Western blot analysis, Masson's trichrome staining, caveolin-1 immunostaining and electron microscopy. The percent of smooth muscle in the trabecular tissue was assessed by computer assisted image analysis., Results: In the aged rats mean intracavernous pressure plus or minus standard deviation was decreased (70 +/- 8.8 versus 107 +/- 12.3 cm. water) and the latency period was increased (7.8 +/- 1.2 versus 4.5 +/- 0.5 seconds) significantly compared to values in the young rats (p <0.001). The mean ratio of trabecular smooth muscle-to-connective tissue was also significantly altered in old versus young rats (27% +/- 2.9% versus 42.1% +/- 5.1%, p <0.001). Immunostaining for caveolin-1 was noted in each group in the sarcolemma of smooth muscle cells and endothelium of trabecular sinusoids but the staining pattern was less intense and the percent of smooth muscle positive for caveolin-1 was decreased in aged versus young rats (17.9% +/- 2.5% versus 27.5% +/- 3.6%, p <0.001). Moreover, young trabecular smooth muscle cells had more caveolae in the sarcolemma on electron microscopy and a higher expression of caveolin-1 protein on Western blot analysis. In contrast, higher endothelial nitric oxide synthase protein expression was noted in the penile tissue of old rats., Conclusions: In these aged rats the decreased ratio of trabecular smooth muscle-to-collagen and the reduced expression of caveolin-1 may contribute to erectile dysfunction.

Penile arterial insufficiency is one of the most common causes of ED. We have established a traumatic arteriogenic insufficiency rat model by the ligation of the pudendal arteries. To simulate both acute and chronic traumatic injuries, five ligation periods (6 h, 3 days, 7 days, 3 weeks, and 6 weeks) were chosen. By electrostimulation of the cavernous nerve, the intracavernous pressure was determined to be between 20 and 40-cm H(2)O for the ligated rats compared to around 100-cm H(2)O for the control rats. The erectile tissue in the corpus cavernosum of these rats was then subjected to microarray analysis, in which an array that contains cDNA fragments representing 1176 rat genes was used. The results demonstrated that normal rat corpus cavernosum expressed approximately 200 genes at detectable levels and that ligation produced differential expression of approximately 25 genes, depending on the duration of ligation. The most highly ligation-induced gene was apolipoprotein D (ApoD), with peak expression in the 3- and 7-day ligated rats. Three of the insulin-like growth factor binding proteins (IGFBP-1, 3, and 5) were upregulated in all ligated rats. IGFBP-6, which was one of the most highly expressed genes in the normal corpus cavernosum, was down-regulated in all ligated rats. Cysteine proteases of the cathepsin family were also differentially expressed between control and ligated rats, with cathepsin K being down-regulated most. A few genes were upregulated only in the 6-week ligated rats, including angiotensin-converting enzyme. Finally, VEGF, whose induction has been identified in many other ischemic tissues, was not induced in corpus cavernous tissue of ligated rats., (Copyright 2001 Academic Press.)

Purpose: We investigated whether cavernous smooth muscle cells secrete vascular endothelial growth factor (VEGF), how they respond to VEGF and how age affects their ability to secrete and respond to VEGF., Materials and Methods: Corpus cavernous tissues were isolated from rats of various ages and grown as monolayer cell cultures. Smooth muscle identity was determined by immunofluorescence staining. Secreted VEGF was measured with a VEGF enzyme-linked immunosorbent assay kit. Cell proliferation was assayed with a cell titer kit. Cell migration was measured with Transwell chambers. VEGF receptor (VEGFR) messenger RNA and proteins were identified by reverse transcription-polymerase chain reaction and immunoblotting, respectively., Results: Cavernous smooth muscle cells from young (age 1 week) and old (age 28 months) rats secreted the least amounts of VEGF and those from 16-week-old rats secreted the most. VEGF stimulated the growth of cavernous smooth muscle cells at an optimal concentration of 12.5 ng./ml. At this concentration cavernous smooth muscle cells from 11-week-old and 28-month-old rats showed the highest and lowest growth rates, respectively. The optimal VEGF concentration for cavernous smooth muscle cell migration was 10 ng./ml. At this concentration cells from 4-week-old and 28-month-old rats showed the highest and lowest migratory rates, respectively. The expression of VEGFR-1 appeared to parallel the VEGF regulated growth rates of these cells. VEGFR-2 was undetectable in cavernous smooth muscle cells., Conclusions: Cavernous smooth muscle cells from rats of different ages secreted different amounts of VEGF and showed different abilities to respond to VEGF. Cavernous smooth muscle cells responded to VEGF in terms of cell proliferation and migration. Cavernous smooth muscle cells from rats of different ages expressed different levels of VEGFR-1 but did not express VEGFR-2.