Expression of cavernous transforming growth factor-beta1 and its Type II Receptor in patients with erectile dysfunction

Caveolin-1 scaffolding domain-derived peptide enhances erectile function by regulating oxidative stress, mitochondrial dysfunction, and apoptosis of corpus cavernosum smooth muscle cells in rats with cavernous nerve injury

AIM

Increased corpus cavernosum smooth muscle cells (CCSMCs) apoptosis in the penis due to cavernous nerve injury (CNI) is a crucial contributor to erectile dysfunction (ED). Caveolin-1 scaffolding domain (CSD)-derived peptide has been found to exert potential antiapoptotic properties. However, whether CSD peptide can alleviate CCSMCs apoptosis and ED in CNI rats remains unknown. The study aimed to determine whether CSD peptide can improve bilateral CNI-induced ED (BCNI-ED) by enhancing the antiapoptotic processes of CCSMCs.

MAIN METHODS

Fifteen 10-week-old male Sprague-Dawley (SD) rats were randomly classified into three groups: sham surgery (Sham) group and BCNI groups that underwent saline or CSD peptide treatment respectively. At 3 weeks postoperatively, erectile function was assessed and the penis tissue was histologically examined. Furthermore, an in vitro model of CCSMCs apoptosis was established using transforming growth factor-beta 1 (TGF-β1) to investigate the mechanism of CSD peptide in treating BCNI-ED.

KEY FINDINGS

In BCNI rats, CSD peptide significantly prevented ED and decreased oxidative stress, the Bax/Bcl-2 ratio, and the levels of caspase3. TGF-β1-treated CCSMCs exhibited severe oxidative stress, mitochondrial dysfunction, and apoptosis. However, CSD peptide partially reversed these alterations.

SIGNIFICANCE

Exogenous CSD peptide could improve BCNI-ED by inhibiting oxidative stress, the Bax/Bcl-2 ratio, and caspase3 expression in penile tissue. The underlying mechanism might involve the regulatory effects of CSD peptide on oxidative stress, mitochondrial dysfunction, and apoptosis of CCSMCs following CNI. This study highlights CSD peptide as an effective therapy for post-radical prostatectomy ED (pRP-ED).

Caveolin-1 scaffolding domain peptide prevents corpus cavernosum fibrosis and erectile dysfunction in bilateral cavernous nerve injury-induced rats

BACKGROUND

Corpus cavernosum (CC) fibrosis significantly contributes to post-radical prostatectomy erectile dysfunction (pRP-ED). Caveolin-1 scaffolding domain (CSD)-derived peptide has gained significant concern as a potent antagonist of tissue fibrosis. However, applying CSD peptide on bilateral cavernous nerve injury (BCNI)-induced rats remains uninvestigated.

AIM

The aim was to explore the therapeutic outcome and underlying mechanism of CSD peptide for preventing ED in BCNI rats according to the hypothesis that CSD peptide may exert beneficial effects on erectile tissue and function following BCNI through limiting collagen synthesis in CC smooth muscle cells (CCSMCs) and CC fibrosis.

METHODS

After completing a random assignment of male Sprague Dawley rats (10 weeks of age), BCNI rats received either saline or CSD peptide treatment, as opposed to sham-operated rats. The evaluations of erectile function (EF) and succedent collection and histological and molecular biological examinations of penile tissue were accomplished 3 weeks postoperatively. In addition, the fibrotic model of CCSMCs was used to further explore the mechanism of CSD peptide action in vitro.

OUTCOMES

The assessments of EF, SMC/collagen ratio, α-smooth muscle actin, caveolin-1 (CAV1), and profibrotic indicators expressions were conducted.

RESULTS

BCNI rats exhibited significant decreases in EF, SMC/collagen ratio, α-SMA, and CAV1 levels, and increases in collagen content together with transforming growth factor (TGF)-β1/Smad2 activity. However, impaired EF, activated CC fibrosis, and Smad2 signaling were attenuated after 3 weeks of CSD peptide treatment in BCNI rats. In vitro, TGF-β1-induced CCSMCs underwent fibrogenetic transformation characterized by lower expression of CAV1, higher collagen composition, and phosphorylation of Smad2; then, the delivery of CSD peptide could significantly block CCSMC fibrosis by inactivating Smad2 signaling.

CLINICAL IMPLICATIONS

Based on available evidence of CSD peptide in the prevention of ED in BCNI rats, this study can aid in the development and clinical application of CSD peptide targeting pRP-ED.

STRENGTHS AND LIMITATIONS

This study provides data to suggest that CSD peptide protects against BCNI-induced deleterious alterations in EF and CC tissues. However, the available evidence still does not fully clarify the detailed mechanism of action of CSD peptide.

CONCLUSION

Administration of CSD peptide significantly retarded collagen synthesis in CCSMCs, limited CC fibrosis, and prevented ED via confrontation of TGF-β1/Smad signaling in BCNI rats.

Genes Predisposing to Erectile Dysfunction and Management: A Review

Background: The burden of erectile dysfunction (ED) is rising worldwide due to unresponsiveness of some affected individuals to existing drugs and treatment strategies. Fortunately, improvement in biological techniques has led to the understanding that some cases of the disorder may have a genetic etiology, which, when fully understood, may lead to improved treatment.

Objective: This review articulated established ED candidate genes and pathophysiology to assist researchers and medical practitioners to formulate effective drugs and treatment procedures.

Methods: The Google search engine was used to retrieve relevant information on the topic from reputable academic databases, including PubMed, Medline, Google Scholar, Scopus, and SpringerLink.

Results: The search discovered 10 ED candidate genes, which are SIM1, SLC6A4, 5-HTTLPR, TGFB1, DAT1, MC4R, NOS3, GNB3, AR, and MTHFR. Polymorphisms or mutations in these genes may disrupt erectile activities of the hypothalamus, neurotransmitters such as dopamine, serotonin, and nitric oxide as well as relaxation of penile tissues. Clinical presentations of ED include loss of erection, weak vaginal penetration, premature ejaculation, and anejaculation. Each gene has a distinct mechanism, which, if targeted in the affected may reverse the disorder or reduce the effects.

Conclusion: Some cases of ED are genetic, which, when fully understood, may give an insight into new treatment procedures or improve on the current ones. Medical practitioners are advised to formulate treatment procedures that target the affected gene (s) in individuals.

Apelin-13 Protects Corpus Cavernosum Against Fibrosis Induced by High-Fat Diet in an MMP-Dependent Mechanism

BACKGROUND

An increased fibrosis of the corpora cavernosa is a prevalent process that underlies most cases of erectile dysfunction. Apelin, an endogenous circulating peptide, has been documented as an important effector on cardiovascular homeostasis, controlling vascular function and reducing fibrosis in multiple pathological conditions. Recently, initial studies have shown that Apelin, acting through the APJ receptor, also modulates penile erection, however, the role of this system on penile structure and intracorporal collagen remodeling has not been investigated yet.

AIMS

Here we sought to investigate the effect of chronic Apelin treatment on the corpus cavernosum structure of hyperchOlesterolemic mice.

METHODS

Apolipoprotein gene-deleted (ApoE^-/-) mice were fed with a Western diet for 11 weeks and received Apelin-13 (2 mg/kg/day) or vehicle during the last 3 weeks. Penile samples were obtained for histological and biochemical analyses to assess the intracorporal collagen content and key proteins expression. Furthermore, the effect of Apelin-13 was evaluated in cultured NIH3T3 mouse fibroblasts stimulated with TGF-β.

OUTCOME

Local expression of Apelin-13 in mouse corpus cavernosum and its protective effect against fibrosis.

RESULTS

Apelin and APJ receptor were expressed (gene and protein) within the corpus cavernosum of ApoE^-/- mice, indicating a local modulation of the Apelin system. Interestingly, 3 weeks of Apelin-13 treatment strongly reduced intracavernosal collagen content. In addition, Apelin-13 enhanced total matrix metalloproteinase (MMP) activity in the mice penis, which was associated with an increased protein expression of MMP-1, MMP-3, MMP-8, and MMP-9, while tissue inhibitor of metalloproteinase were unaltered. These beneficial actions were not associated with changes in nNOS or eNOS protein expression, intracavernosal reactive oxygen species content, or atherosclerotic plaque deposition. Additionally, in cultured fibroblast, Apelin-13 inhibited TGF-β-induced fibroblast to myofibroblast differentiation and collagen production, possibly through the activation of ERK1/2 kinase.

CLINICAL TRANSLATION

These results point out Apelin/APJ system as a potential target to treat intracavernosal fibrosis-related disorders.

STRENGTH & LIMITATIONS

These results provide the first evidence of the Apelin system's positive role on erectile tissue structure/remodeling. Nevertheless, additional functional study addressing erectile response would bring extended validation regarding the relevance of such effect.

CONCLUSION

These results suggest a local modulation of the Apelin system within the corpus cavernosum. Remarkably, Apelin-13 reduced intracavernosal fibrosis in hypercholesterolemic mice by: (i) enhancing MMPs expression and activity; and (ii) inhibiting fibroblast differentiation into myofibroblast. Altogether, these results suggest an essential protective role of Apelin, indicating Apelin/APJ system as a promising candidate for the development of fibrosis-associated erectile dysfunction treatments. Sturny M, Anguenot L Costa-Fraga FP, et al. Apelin-13 Protects Corpus Cavernosum Against Fibrosis Induced by High-Fat Diet in an MMP-Dependent Mechanism. J Sex Med 2021;18:875-888.

Simvastatin alleviated diabetes mellitus-induced erectile dysfunction in rats by enhancing AMPK pathway-induced autophagy

BACKGROUND

Diabetes mellitus-induced erectile dysfunction is a common diabetic complication, and new therapeutics and the pathogenesis of diabetes mellitus-induced erectile dysfunction need to be investigated.

OBJECTIVES

The aim was to investigate the pathogenesis of diabetes mellitus-induced erectile dysfunction and the pharmacological mechanism of simvastatin treatment in diabetes mellitus-induced erectile dysfunction model rats.

MATERIALS AND METHODS

A total of 86 male Sprague Dawley rats aged 8 weeks old were used in this study. The rats were divided into three groups: control (normal), diabetes mellitus-induced erectile dysfunction (streptozotocin-injected), and diabetes mellitus-induced erectile dysfunction + simvastatin (sim). Each group was subdivided into two subgroups for in vitro and in vivo analyses. A bioinformatics method was used to detect differences in gene expression in the corpus cavernosum between normal and diabetes mellitus-induced erectile dysfunction rats. Erectile function was measured by a cavernous nerve electrostimulation test. Corpus cavernosum fibrosis was assessed by Masson staining and Western blotting. Immunofluorescence and Western blotting were performed to explore the differential expression of autophagy-related genes and the AMPK-SKP2-CARM1 pathway genes in rat cavernous smooth muscle cells and the corpus cavernosum. The autophagosomes of the corpus cavernosum tissue were observed by transmission electron microscopy.

RESULTS

Autophagy-related genes and pathways (the AMPK and FoxO pathway) were identified by bioinformatics analysis and confirmed at the protein level. Simvastatin, an AMPK agonist, was used to treat diabetes mellitus-induced erectile dysfunction rats for 8 weeks, demonstrating that erectile function was improved for 80.5% (P < .05) of rats. Corpus cavernosum fibrosis was alleviated (P < .05), and autophagy was further enhanced (P < .05); these results might be partially caused by AMPK-SKP2-CARM1 pathway activation (P < .05).

DISCUSSION AND CONCLUSION

Simvastatin could enhance protective autophagy by activating the AMPK-SKP2-CARM1 pathway to improve erectile function in diabetes mellitus-induced erectile dysfunction rats.

Transplantation of adipose-derived stem cells overexpressing inducible nitric oxide synthase ameliorates diabetes mellitus-induced erectile dysfunction in rats

Background

Erectile dysfunction is a major complication of diabetes mellitus. Adipose-derived stem cells (ADSCs) have attracted much attention as a promising tool for the treatment of diabetes mellitus-induced erectile dysfunction (DMED). Inducible nitric oxide synthase (iNOS) plays an important role in protecting penile tissues from fibrosis. The aim of this study was to determine the efficacy of ADSCs overexpressing iNOS on DMED in rats.

Methods

ADSCs were isolated and infected with adenovirus overexpressing iNOS (named as ADSCs-iNOS). The expression of iNOS was detected using western blot analysis and real-time PCR. Rats were randomly assigned into five groups: control group, DMED group, ADSCs group, ADSCs-EGFP group and ADSCs-iNOS group. 5 × 10⁵ cells were given once via the intracorporal route. Two weeks after treatment, erectile function was assessed by electrical stimulation of the cavernous nerve. Penile tissues were obtained and evaluated at histology level.

Results

We found that ADSCs-iNOS had significantly higher expression of iNOS at mRNA and protein levels and generated more nitric oxide (NO). ADSCs-iNOS reduced collagen I and collagen IV expression of corpus cavernosum smooth muscle cells (CCSMCs) in cell co-culture model. Transforming growth factor-β1 expression in CCSMCs reduced following co-culture with ADSCs-iNOS. Injection of ADSCs-iNOS significantly ameliorated DMED in rats and decreased collagen/smooth muscle cell ratio of penile tissues. Moreover, elevated NO and cyclic guanosine monophosphate concentrations were detected in penile tissues of ADSCs-iNOS group.

Conclusion

Taken together, ADSCs-iNOS significantly improved erectile function of DMED rats. The therapeutic effect may be achieved by increased NO generation and the suppression of collagen I and collagen IV expression in the CCSMCs to decrease penile fibrosis.

Serum Biomarkers of Erectile Dysfunction in Diabetes Mellitus: A Systematic Review of Current Literature

INTRODUCTION

Erectile dysfunction (ED) is a common complication in patients with diabetes mellitus (DM). However, the utility of serum biomarkers as clinical surrogates for the development and/or progression of ED is unknown.

AIM

To summarize the current literature for serum biomarkers for ED in DM and emphasize areas for future research.

MAIN OUTCOME MEASURES

Human subject data demonstrating the utility of serum markers for the development and progression of ED in patients with DM.

METHODS

We performed a systematic PubMed-Medline search in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement using Medical Subject Headings (MeSH) for articles published from January 1, 2000 through December 31, 2016 of serum biomarkers for development or progression of ED in patients with DM using erectile dysfunction [MeSH] AND (biomarkers [MeSH] or inflammation mediators [MeSH] or intercellular signaling peptides and proteins [MeSH] or cell adhesion molecules [MeSH]). A thorough review of these studies was completed.

RESULTS

Of the 327 abstracts screened, 12 full-text studies were assessed and 1 study was excluded. Eleven studies assessing serum biomarkers for ED in patients with DM were included in this review. The most studied serum biomarkers for ED in men with DM included endothelial dysfunction markers such as serum E-selectin, endothelial progenitor cells, and endothelial microparticles and specific markers of inflammation such as interleukin-10, ratio of tumor necrosis factor-α to interleukin-10, and reactive oxygen species such as nitric oxide and malondialdehyde. Reliable serum biomarkers will enable earlier diagnosis and objective monitoring of disease progression and responses to treatment in patients with ED.

CONCLUSION

Serum biomarkers for ED in men with DM are very limited. Future longitudinal studies with uniform patient characteristics are needed to evaluate the potential clinical use of serum biomarkers in men with DM for the development and progression of ED. Patel DP, Craig JR, Myers JB, et al. Serum Biomarkers of Erectile Dysfunction in Diabetes Mellitus: A Systematic Review of Current Literature. Sex Med Rev 2017:5:339-348.

Research in pharmacotherapy for erectile dysfunction

Although oral phosphodiesterase-5 (PDE5) inhibitors are generally accepted as an effective therapy for erectile dysfunction (ED), men with ED from diabetes or radical prostatectomy respond poorly to these drugs. Many researchers have tried to develop novel therapeutics that target alternative molecular pathways. A group of therapeutics belongs to centrally acting agents that target dopamine and melanocortin receptors. The other one is the peripherally acting agents that target soluble guanylate cyclase, Rho-kinase pathway, and Maxi-K channel, etc. Also, a variety of preclinical studies by the application of biotherapies in the concept of therapeutic angiogenesis or neural regeneration as well as anti-fibrosis to regenerate damaged erectile tissue have been reported. This article will address the current therapeutic targets for ED under clinical or preclinical development, including pharmacotherapy and biotherapy which comprises protein therapy and gene therapy. In spite of numerous clinical trials that target alternative pathways, these agents have yet to reach the market. The results from preclinical studies targeting therapeutic angiogenesis, neural regeneration, and anti-fibrosis are promising.

Chronic Rhinosinusitis Associated with Erectile Dysfunction: A Population-Based Study

Few studies have investigated the relationship between chronic rhinosinusitis (CRS) and erectile dysfunction (ED). This case-control study aimed to investigate the association between CRS and the risk of ED in a large national sample. Tapping Taiwan's National Health Insurance Research Database, we identified people 30 years or older with a new primary diagnosis of CRS between 1996 and 2007. The cases were compared with sex- and age-matched controls. We identified 14 039 cases and recruited 140 387 matched controls. Both groups were followed up in the same database until the end of 2007 for instances of ED. Of those with CRS, 294 (2.1%) developed ED during a mean (SD) follow-up of 3.20 (2.33) years, while 1 661 (1.2%) of the matched controls developed ED, mean follow up 2.97 (2.39) years. Cox regression analyses were performed adjusting for sex, age, insurance premium, residence, hypertension, hyperlipidemia, diabetes, obesity, coronary heart disease, chronic kidney disease, chronic obstructive pulmonary disease, asthma, allergic rhinitis, arrhythmia, ischemic stroke, intracerebral hemorrhage, and medications. CRS was revealed to be an independent predictor of ED in the fully adjusted model (HR = 1.51; 95% CI = 1.33-1.73; P < 0.0001).

Sonic hedgehog delivery from self-assembled nanofiber hydrogels reduces the fibrotic response in models of erectile dysfunction

Erectile dysfunction (ED) is a serious medical condition in which current treatments are ineffective in prostatectomy and diabetic patients, due to injury to the cavernous nerve (CN), which causes irreversible remodeling of the penis (decreased smooth muscle and increased collagen), through a largely undefined mechanism. We propose that sonic hedgehog (SHH) and neural innervation, are indispensable regulators of collagen in the penis, with decreased SHH protein being an integral component of the fibrotic response to loss of innervation. We examined collagen abundance and morphology in control (Peyronie's), prostatectomy and diabetic patients, and in rat models of penile development, CN injury, SHH inhibition and under regenerative conditions, utilizing self-assembling peptide amphiphile (PA) nanofiber hydrogels for SHH delivery. Collagen abundance increased in penis of ED patients. In rats, collagen increased with CN injury in a defined time frame independent of injury severity. An inverse relationship between SHH and collagen abundance was identified; SHH inhibition increased and SHH treatment decreased penile collagen. SHH signaling in the pelvic ganglia (PG)/CN is important to maintain CN integrity and when inhibited, downstream collagen induction occurs. Collagen increased throughout penile development and with age, which is important when considering how to treat fibrosis clinically. These studies show that SHH PA treatment reduces collagen under regenerative post-prostatectomy conditions, indicating broad application for ED prevention in prostatectomy, diabetic and aging patients and in other peripheral nerve injuries. The PA nanofiber protein vehicle may be widely applicable as an in vivo delivery tool.

STATEMENT OF SIGNIFICANCE

We use self-assembling peptide amphiphiles (PA) as biological delivery vehicles to prevent cavernous nerve (CN) injury induced erectile dysfunction (ED). These versatile hydrogels were molecularly pre-programmed for sonic hedgehog (SHH) protein delivery, either from an injectable solution with fast, in situ assembly into a soft hydrogel, or by highly aligned monodomain nanofiber bundles. We used PAs to examine a novel neuronal component to collagen regulation and the role of SHH in the fibrotic response to CN injury. SHH perturbation in the penis or the CN, selectively impacts collagen, with SHH inhibition increasing and SHH treatment suppressing collagen. These results suggest that SHH treatment by PA has translational potential to suppress collagen induction and remodelling, an irreversible component of ED development.

Impact of nasal polyposis on erectile dysfunction

BACKGROUND

Our male patients with chronic rhinosinusitis with nasal polyposis (NP) declare a better sexual function after functional endoscopic sinus surgery (FESS) with polypectomy. This study was planned to conduct the first prospective, controlled trial evaluating the possible relation between erectile dysfunction (ED) and NP by subjective and objective parameters.

METHODS

Thirty-three male patients with NP and thirty randomly selected male control subjects were evaluated. All subjects underwent assessments of nasal endoscopy, rhinomanometry, body mass index (BMI), Epworth Sleepiness Scale, full in-laboratory polysomnograpy and serum levels of glucose, thyroid hormones, lipid profile, and testosterone. ED was evaluated by the erectile function domain of the International Index of Erectile Function (IIEF-EF) subjectively and nocturnal penile tumescence (NPT) objectively. The NP group was reassessed 6 months after FESS.

RESULTS

The mean age, BMI, and laboratory tests of the patients and the control subjects had no significant difference. The well-recognized risk factors for ED were eliminated. Preoperative evaluation of the patients revealed that ED was present in 34 and 24% of the patients by IIEF-EF and NPT, respectively, which was significantly higher than the control group (p = 0.009 and p = 0.018, respectively). There was a significant improvement of ED in the assessment of IIEF-EF and NPT postoperatively (p = 0.014 and p = 0.037, respectively).

CONCLUSION

ED was determined in a high percentage of patients with NP and significantly ameliorated after FESS. NP might present a risk factor in the development of ED.

Testosterone, endothelial health, and erectile function

Experimental and clinical studies have reported that testosterone has a critical role in the maintenance of homeostatic and morphologic corpus cavernosum components, essential for normal erectile physiology. Although the exact mechanisms mediated by testosterone in erectile function are still under investigation, recent research has suggested an important role in the regulation of endothelial cell (EC) biological functions. Besides stimulating the production of EC mediators, testosterone is also thought to promote the vasculogenic reendothelialization process, mediated by bone marrow-derived endothelial progenitor cells. Additionally, testosterone seems to modulate other erectile tissue components, including trabecular smooth muscle cells, nerve fibers, and tunica albuginea structure, all essential for the erectile process. This paper summarizes current data regarding testosterone-induced cellular and molecular mechanisms that regulate penile tissue components, focusing particularly on the role of testosterone in endothelial health and erectile function.

Erectile tissue molecular alterations with aging: differential activation of the p42/44 MAP Kinase pathway

Erectile dysfunction (ED) is a common problem in aged men; however, the molecular events involved in aging ED remain unclear. To better characterize the effects of aging in the penis, we evaluated cavernosal tissue remodeling capability and the downstream activation of the intracellular signaling mediator mitogen-activated protein p42/44 kinase (p42/44 MAPK). We used male Wistar rats, which were divided in groups of 2, 6, 12, 18, and 24 months old. Penile tissues were harvested and processed for protein isolation and immunohistochemical analysis. Cavernosal viability was assessed by TUNEL assay, and proliferation was analyzed by immunohistochemical detection of proliferating cell nuclear antigen (PCNA). Immunolocalization of the activated form of p42/44 MAPK was evaluated by immunofluorescence, and changes in its phosphorylation status were quantified by western blotting. p42/44 phosphorylation profile was also assessed in situ in human young and elderly cavernosal samples. With the advancement of age, experimental cavernosal tissue remodeling was affected by an age-dependent unbalance between the rate of apoptosis and proliferation, in all erectile components. Moreover, this turnover alteration was accompanied by significant modifications in the activation profile of the downstream effector p42/44 MAPK. In the youngest corporeal samples, p42/44 was mostly activated at perivascular sites, potentially mediating cell survival/proliferation. However, in elderly experimental erectile tissue, p42/44 phosphorylation shifted to trabecular fibroblasts, indicating a potential role in extracellular matrix (ECM) production. More importantly, the same differential pattern of p42/44 activation was observed in human young and aged cavernosal fragments, suggesting a distinct function of this protein with aging. We provided evidence for the first time that with the advancement of age, there is a differential activation of p42/44 MAPK in cavernosal tissue, which may promote ECM expansion and fibrosis, therefore compromising erectile function in the elderly.

The mouse as a model for the study of penile erection: moving towards a smaller animal

We evaluated erectile haemodynamics in mice and characterized the corpus cavernosum morphologically. Four-month-old male BALB/c mice and Sprague-Dawley rats were used. The following stimulation parameters were tested to achieve maximal erectile responses: voltage, 1-6 V; frequency, 6-24 Hz; pulse width, 1 msec; duration, 1 min (n = 7 per group). In a separate group of mice and rats (n = 10 per group), we measured systemic arterial pressure by use of either a 24-gauge angiocatheter or smaller calibre PE-10 tubing. Cavernous tissues from mice, rats or patients with psychogenic erectile dysfunction were stained for factor VIII, alpha-actin and Masson trichrome. Electrical stimulation of the cavernous nerve in mice produced voltage-dependent erectile responses of up to 5 V, with the highest response at a frequency of 12 Hz. The maximal intracavernous pressure recorded at this stimulation parameter was comparable with that in rats. A PE-10 catheter was more reliable for measuring systemic arterial pressure in mice than was a 24-gauge angiocatheter, and the values recorded were similar between mice and rats. The content of endothelial cells, smooth muscle cells and collagen was similar between mice and rats. However, the cavernous tissue of both animals contained lesser amounts of smooth muscle cells and greater amounts of collagen than that of humans (p < 0.01). These results suggest that the mouse is a useful and technically feasible model for the study of penile erection and has functional and structural properties similar to those of rats.

Correlates of erectile dysfunction in moderate-to-severe chronic obstructive pulmonary disease patients

OBJECTIVE AND BACKGROUND

Erectile dysfunction (ED) has important negative effects on male quality of life and self-esteem. The aim of this study was to acquire an insight into the sexual status of COPD patients.

METHODS

Ninety-five male patients aged 48-75 years, with moderate-to-severe stable COPD, and 30 age-matched subjects with normal pulmonary function were included. After clinical evaluation and measurement of serum sex hormones and TNF-alpha concentration, subjects were asked to answer the International Index of Erectile Function (IIEF) questionnaire as a method to diagnose and classify ED.

RESULTS

Varying degrees of ED were detected in 87% of COPD patients and 83% of controls. Although the total percentages of subjects with various severities of ED seemed similar, moderate and severe ED was 57% in COPD group and 20% in control subjects, suggesting a more severe course of ED in COPD patients. ED score of COPD patients was not correlated with age, smoking burden, duration of COPD, FEV1%, PaO2, PaCO2, serum dehydroepiandrosterone-sulphate, testosterone or estradiol levels. When patients were subgrouped according to severity of ED, serum TNF-alpha concentration, used as a marker of systemic inflammatory status in COPD, was significantly higher in patients with moderate-to-severe ED compared with mild-moderate ED.

CONCLUSION

The present study showed that ED is frequent and more severe in COPD patients than age-matched controls. Chronic systemic inflammation is likely to play a role in ED in COPD; the role of TNF-alpha should be evaluated further. Patients with COPD need comprehensive management including a detailed sexual evaluation.

Peak systolic velocity in patients with arterial erectile dysfunction and peripheral arterial disease

The aim of this study is to evaluate whether penile peak systolic velocity (PSV) varies in patients with erectile dysfunction (ED) due to artery insufficiency associated with abnormalities in other arterial districts or not. To accomplish this, cavernous artery PSV was determined 10, 20 and 30 min after intracavernously administering alprostadil by means of echo-color Doppler to a total of 65 consecutive patients (age range 52-78 years). In all, 18 patients had ED alone (group A) and served as controls, 15 had ED plus atheroma plaques and/or marked intima-media thickness of the common carotid artery (group B); 17 had ED plus lower limb artery abnormalities; 17 had ED plus carotid and lower limb artery abnormalities (group D). Group B and C patients had a similar PSV, which turned out to be significantly lower than that in group A. Group D patients had the lowest PSV, which proved to be significantly lower than that in groups A, B and C. This study shows that a more generalized peripheral atherosclerotic process is associated with a severer penile artery insufficiency. Therefore, ED patients with a severe arterial insufficiency should undergo an extensive echo-duplex examination.

Incidence of extragenital vascular disease in patients with erectile dysfunction of arterial origin

This research was carried out to evaluate the prevalence of carotid and/or lower limb artery abnormalities in patients with arterial erectile dysfunction (ED). To this end, patients with ED (Andrology Unit) or suspected peripheral atherosclerosis (Angiology Unit) underwent an independent and parallel echo-Duplex examination. The Andrology Unit examined 167 patients with ED of different etiologies: 52 of them had penile artery insufficiency and consequently their carotids and lower limb arteries had to be evaluated by means of echo-Doppler. In all, 36 out of the 46 patients with nonarterial organic ED and 22 out of the 69 patients with nonorganic ED underwent the same evaluation and served as controls. The Angiology Unit enrolled 457 ED patients who initially underwent echo-Doppler for suspected carotid and/or arterial leg atherosclerosis and subsequently dynamic echo-Doppler. Isolated penile artery insufficiency was found in 23.1 and 25% of the patients evaluated in the Angiology and Andrology Units, respectively. The remaining patients were shown to have ED associated with an atheroma or marked intima-media thickness of the carotid vessels and/or of leg arteries. The frequency of penile arterial insufficiency and of carotid and/or lower limb artery abnormalities was significantly higher (P < 0.01) compared to that found in patients with ED of nonarterial organic or psychogenic origin. Both Units found that the frequency of penile artery insufficiency and carotid or lower limb artery abnormalities was significantly higher than that of penile artery insufficiency alone or plus both carotid and lower limb artery abnormalities. This study showed that penile artery insufficiency is associated with carotid and/or lower limb artery ultrasound abnormalities in about 75% of the cases. Therefore, arterial ED may be regarded as a sign of a more generalized atherosclerosis.