The endothelial-erectile dysfunction connection: an essential update

Abnormal endothelial function in ED patients with normal nocturnal penile tumescence and rigidity: is it the role of psychogenic factors?

Underlying endothelial dysfunction (EnD) may present in the early stage of ED or psychogenic ED. We retrospectively evaluated 191 ED patients with effective nocturnal penile tumescence and rigidity (NPTR) recording, including detailed medical and psychosexual history, International Index of Erectile Function-5 and vascular parameter. All patients were allocated into psychogenic and organic groups according to the NPTR test. Brachial artery flow-mediated dilation (FMD) was used to diagnose EnD, and ED patients were classified into two groups: non-EnD (FMD10) and EnD (FMD<10). General and vascular parameters were compared between psychogenic and organic groups, and non-EnD and EnD groups with ED were compared in terms of NPTR parameters. In all, 48.7% and 51.3% patients were diagnosed as psychogenic and organic ED, respectively. 73.1% of the psychogenic patients had EnD and 39.8% organic patients had normal endothelial function. In all parameters, only the FMD value showed significant difference between psychogenic and organic ED groups (8.26±2.57 vs 9.16±2.76, P=0.020). No statistical difference was founded in NPTR parameters between non-EnD and EnD groups (P>0.05). In conclusion, NPTR cannot effectively identify the underlying vasculogenic ED from psychogenic ED. Psychogenic causes may cause or aggravate EnD in these ED patients with normal NPTR.

Does radical nephrectomy increase the risk of erectile dysfunction compared with partial nephrectomy? A cohort analysis

Study Type - Therapy (prospective cohort) Level of Evidence 2b What's known on the subject? and What does the study add? Erectile dysfunction (ED) is a form of endothelial dysfunction that is prevalent in patients with chronic kidney disease (CKD). We hypothesized that partial nephrectomy (PN) would limit development of ED compared with radical nephrectomy (RN), primarily due to renal function preservation, and found that patients undergoing RN had significantly higher de novo ED compared with a contemporary, well-matched cohort undergoing PN; in addition to RN, hypertension, CKD and diabetes mellitus were associated with developing ED. To our knowledge, this is the first study demonstrating an increased risk of ED after RN compared with PN.

OBJECTIVES

•  To evaluate prevalence and risk factors for development of erectile dysfunction (ED) in patients who underwent radical nephrectomy (RN) and partial nephrectomy (PN). •  ED is a form of endothelial dysfunction that is prevalent in patients with chronic kidney disease (CKD). PN confers superior renal functional preservation compared with RN; however, the impact on ED is unclear.

METHODS

•  This was a retrospective study of 432 patients (264 RN/168 PN, mean age 58 years, mean follow-up 5.8 years) who underwent surgery for renal tumours between January 1998 and December 2007. •  The primary outcome was rate of de novo ED postoperatively. Secondary outcomes included development of CKD (estimated GFR < 60 mL/min/1.73 m(2) ) and response to phosphodiesterase-5 inhibitors. •  Multivariate analysis was performed to determine risk factors for de novo ED postoperatively.

RESULTS

•  RN and PN groups had similar demographics and comorbidities. •  Tumour size (cm) was larger for RN (RN 7.0 vs PN 3.7, P < 0.001) and more preoperative ED existed in PN vs RN (P= 0.042). No differences were observed for preoperative CKD, hyperlipidaemia and diabetes mellitus. •  Postoperatively, higher rates of de novo ED (29.5% vs 9.5%, P < 0.001) and CKD (33.0% vs 9.8%, P < 0.001) developed in RN vs PN cohorts, respectively. •  Of men with ED, 63% responded to phosphodiesterase inhibitors, without significant difference between the two groups (P= 0.896). •  Multivariate analysis demonstrated de novo ED to be associated with RN (odds ratio [OR] 3.56, P < 0.001), hypertension (OR 2.32, P= 0.014), preoperative (OR 8.77, P < 0.001) and postoperative (OR 2.64, P= 0.001) CKD, and postoperative diabetes mellitus (OR 2.93, P < 0.001).

CONCLUSIONS

•  Patients undergoing RN had significantly higher de novo ED compared with a contemporary, well-matched cohort undergoing PN. In addition to RN, hypertension, CKD and diabetes mellitus were associated with developing ED. •  Further investigation on effects of surgically induced nephron loss on ED is requisite.

Defining the impact of vascular risk factors on erectile function recovery after radical prostatectomy

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Erectile function recovery after radical prostatectomy is affected by surgical technique and patient factors. Age and preoperative erectile function are the 2 patient factors that have been consistently shown to impact postoperative erectile function. The presence of vascular risk factors preoperatively seems to negatively impact erectile function recovery after radical prostatectomy independently from age, preoperative erectile function and surgical technique.

OBJECTIVE

To examine whether vascular risk factors (VRFs) affect erectile function (EF) recovery after radical prostatectomy (RP).

PATIENTS AND METHODS

From our prospective database we identified patients with clinically localised prostate cancer who had undergone RP and had preoperative information on EF and VRFs (hypertension, hypercholesterolaemia, diabetes mellitus, coronary artery disease [CAD], and cigarette smoking), surgeon-graded nerve-sparing status, and EF data collected between 24 and 30 months after RP.

RESULTS

In all, 984 patients were included in the analyses. The frequency of the VRFs was as follows: hypertension (38%), hypercholesterolaemia (36%), diabetes mellitus (7%), CAD (5%), and cigarette smoking (37%). On univariate analysis, EF between 24 and 30 months was associated with age (r = 0.37, P < 0.001), EF before RP (r = 0.41, P < 0.001), NSS (r = 0.35, P < 0.001), and VRFs (0-2 vs >3 VRFs; r = 0.15, P = 0.003). On multivariable analysis all variables remained statistically significant, and accounted for 28% of the total variance in EF between 24 and 30 months after RP.

CONCLUSIONS

The presence of VRFs seems to adversely affect EF recovery after RP independently of other factors. This observation might be useful for improving patient counselling before treatment and to support the development of new treatment strategies for erectile dysfunction after RP.

New insights into hypertension-associated erectile dysfunction

PURPOSE OF REVIEW

Erectile dysfunction is recognized as a quality-of-life disorder that needs to be treated. Currently, it is estimated to affect as many as 30 million American men. Thirty percent of hypertensive patients complain of erectile dysfunction. The understanding of common mechanisms involved in the cause of erectile dysfunction associated with hypertension, and the investigation of antihypertensive drugs that impact erectile dysfunction, will provide important tools toward identifying new therapeutic targets that will improve the quality of life for patients in these conditions.

RECENT FINDINGS

Hypertension and erectile dysfunction are closely intertwined diseases, which have endothelial dysfunction as a common base. During hypertension and/or erectile dysfunction, disturbance of endothelium-derived factors can lead to an increase in vascular smooth muscle (VSM) contraction. Hypertension can lead to erectile dysfunction as a consequence of high blood pressure (BP) or due to antihypertensive treatment. However, growing evidence suggests erectile dysfunction is an early sign for hypertension. Also, some phosphodiesterase-5 inhibitors used to treat erectile dysfunction can improve BP, but the link between these conditions has not been totally understood.

SUMMARY

This review will discuss the interplay between hypertension and erectile dysfunction, exploring newest insights regarding hypertension-associated erectile dysfunction, as well as the effect of antihypertensive drugs in erectile dysfunction patients.

Scaffoldless tissue engineering of stem cell derived cavernous tissue for treatment of erectile function

INTRODUCTION

As one-third of erectile dysfunction (ED) patients do not respond to phosphodiesterase-5 inhibitors, there is great demand for new therapeutic options. Adipose tissue-derived stem cells (ADSCs) represent an ideal source for new ED treatment.

AIM

To test if ADSCs can be differentiated into smooth muscle cells (SMCs) and endothelial cells (ECs), if these differentiated cells can be used to engineer cavernous tissue, and if this engineered tissue will remain for long time after implantation and integrate into corporal tissue.

METHOD

Rat ADSCs were isolated and differentiated into SMC and ECs. The differentiated cells were labeled with 5-ethynyl-2-deoxyuridine (EdU) and used to construct cavernous tissue. This engineered tissue was implanted in penises of normal rats. The rats were sacrificed after 1 and 2 months; penis and bone marrow were collected to assess cell survival and inclusion in the penile tissues.

MAIN OUTCOME MEASURES

The phenotype conversion was checked using morphology, immunocytochemistry (immunohistochemistry [IHC]), and Western blot for SMC and EC markers. The cavernous tissue formation was assessed using rat EC antibody (RECA), calponin, and collagen. The implanted cell survival and incorporation into penis were evaluated with hematoxylin and eosin, Masson's trichrome, and IHC (RECA, calponin, and EdU).

RESULTS

The phenotype conversion was confirmed with positive staining for SMC and EC markers and Western blot. The formed tissue exhibited architecture comparable to penile cavernous tissue with SMC and ECs and extracellular matrix formation. The implanted cells survived in significant numbers in the penis after 1 and 2 months. They showed proof of SMC and EC differentiation and incorporation into penile tissue.

CONCLUSIONS

The results showed the ability of ADSCs to differentiate into SMC and ECs and form cavernous tissue. The implanted tissue can survive and integrate into the penile tissues. The cavernous tissue made of ADSCs forms new technology for improvement of in vivo stem cell survival and ED treatment.

Aerobic physical activity improves endothelial function in the middle-aged patients with erectile dysfunction

OBJECTIVE

Physical activity (PhA) has proven to be a protective factor for normal erectile function. The aim of this study was to evaluate the effects of a standard protocol of aerobic PhA on quality of erectile dysfunction (ED) in patients with arterial ED.

MATERIALS AND METHODS

Fifty patients (48-62 years) were selected and underwent to standard protocol of aerobic PhA: 150 min of moderate intensity aerobic activity per week (group A). Twenty patients, matched aged, with vascular ED who did not accept to undergo the standard PhA's protocol, represented the control group. All patients were evaluated, by IIEF-5 questionnaire administration, penile eco color doppler and flow-cytometric analysis for detection of serum concentrations of original immunophenotype endothelial progenitor cells (EPCs) = CD45neg/CD34pos/CD144pos and endothelial microparticles (EMPs) = CD45neg/CD34neg/CD144pos.

RESULTS

After 3 months, group A showed IIEF 5 score and peak systolic velocity significantly higher (p < 0.05) compared to controls, and significantly lower values (p < 0.05) of acceleration time, in addition serum concentrations of EPCs and EMPs were significantly lower (p < 0.05) in group A compared to controls.

CONCLUSIONS

PhA improves quality of arterial ED, without other pharmacological approach, probably by reduced endothelial apoptosis. This study characterises the study of endothelial dysfunction by new cell circulating markers.

Arterial erectile dysfunction: reliability of new markers of endothelial dysfunction

OBJECTIVE

Blood endothelial progenitor cells (EPC) and microparticles (EMP) have been proposed as markers of endothelial dysfunction. Aim of this study was to evaluate a new immunophenotype of EPC and EMP in patients with arterial erectile dysfunction (AED) compared to psychogenic erectile dysfunction (PED).

MATERIALS AND METHODS

One hundred patients (63.2±2.6 yr) with AED were enrolled in this study. Their EPC and EMP concentrations were compared to those of 40 patients with PED (64.2±2.7 yr). EPC (CD45(neg)/CD34(pos)/ CD144(pos)) and EMP (CD45(neg)/CD144(pos)/AnnexinV(pos)) blood concentrations were evaluated by flow cytometry.

RESULTS

Patients with AED had significantly higher blood pressure, triglycerides, homeostasis model assessment index of insulin resistance, and cavernous artery acceleration time and intima-media thickness than PED; whereas international index of erectile function 5 score, HDL-cholesterol, and cavernous artery peak systolic velocity was lower than PED. Both EPC and EMP were significantly higher in patients with AED compared to patients with PED.

CONCLUSIONS

Patients with AED showed worse metabolic parameters, cavernous artery parameters, and higher EPC and EMP compared to patients with PED. This suggests that AED is an expression of endothelial dysfunction and that EPC and EMP may be considered predictors of endothelial dysfunction in patients with AED.

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.

Comparing effects of a low-energy diet and a high-protein low-fat diet on sexual and endothelial function, urinary tract symptoms, and inflammation in obese diabetic men

INTRODUCTION

Abdominal obesity and type 2 diabetes mellitus are associated with sexual and endothelial dysfunction, lower urinary tract symptoms (LUTS), and chronic systemic inflammation.

AIM

To determine the effects of diet-induced weight loss and maintenance on sexual and endothelial function, LUTS, and inflammatory markers in obese diabetic men.

MAIN OUTCOME MEASURES

Weight, waist circumference (WC), International Index of Erectile Function (IIEF-5) score, Sexual Desire Inventory (SDI) score, International Prostate Symptom Scale (IPSS) score, plasma fasting glucose and lipids, testosterone, sex hormone binding globulin (SHBG), inflammatory markers (high-sensitivity C-reactive protein [CRP] and interleukin-6 [IL-6]) and soluble E-selectin, and brachial artery flow-mediated dilatation (FMD) were measured at baseline, 8 weeks, and 52 weeks.

METHODS

Over 8 weeks, 31 abdominally obese (body mass index ≥ 30 kg/m(2) , WC ≥ 102 cm), type 2 diabetic men (mean age 59.7 years) received either a meal replacement-based low-calorie diet (LCD) ∼1,000 kcal/day (N = 19) or low-fat, high-protein, reduced-carbohydrate (HP) diet (N = 12) prescribed to decrease intake by ∼600 kcal/day. Subjects continued on, or were switched to, the HP diet for another 44 weeks.

RESULTS

At 8 weeks, weight and WC decreased by ∼10% and ∼5% with the LCD and HP diet, respectively. Both diets significantly improved plasma glucose, low-density lipoprotein (LDL), SHBG, IIEF-5, SDI and IPSS scores, and endothelial function (increased FMD, reduced soluble E-selectin). Erectile function, sexual desire, and urinary symptoms improved by a similar degree with both diets. CRP and IL-6 decreased with the HP diet. At 52 weeks, reductions in weight, WC, and CRP were maintained. IIEF-5, SDI, and IPSS scores improved further.

CONCLUSIONS

Diet-induced weight loss induces rapid improvement of sexual, urinary, and endothelial function in obese diabetic men. A high-protein, carbohydrate-reduced, low-fat diet also reduces systemic inflammation and sustains these beneficial effects to 1 year.

Dysfunction of the endothelial-platelet pathway in patients with erectile dysfunction before and after daily treatment with tadalafil

Platelet activation results from the exposure of receptors on the surface of the platelet to specific structures on the vessel wall. The aim of this study was to assess the serum concentrations of apoptotic endothelial microparticles (EMPa) and the vitronectin receptor (VR) in patients with erectile dysfunction (ED) before and after treatment with tadalafil. This study included 50 patients with arterial ED. EMPa and VR levels were measured by using flow cytometry. The CD45(neg)-CD144(pos)-annexin V(Pos) events were defined as EMPa, and the CD51(pos)-CD61(pos) events were defined as VR. Patients with ED were evaluated before and after daily treatment with 5 mg tadalafil for 90 days. Patients with arterial ED had serum concentrations of EMPa and VR significantly higher than the control group at baseline. After tadalafil, the serum concentrations of EMPa and VR of the patients with arterial ED were significantly lower than before treatment, but significantly higher than controls. Patients with arterial ED expressed higher levels of both EMPa that are associated with dysfunction of the arterial endothelial pathway and VR-expressing platelet-endothelial elements. Chronic treatment with tadalafil reduced endothelial apoptosis in these patients and also reduced VR expression.

Prevalence and detection rate of underlying disease in men with erectile dysfunction receiving phosphodiesterase type 5 inhibitors in the United Kingdom: a retrospective database study

AIM

To determine the rate of newly detected underlying disease in men receiving their first (index) phosphodiesterase type 5 inhibitor (PDE5i) prescription.

METHODS

This non-interventional, retrospective study used anonymised patient records from UK general practices identified from the THIN database. Records of men aged ≥ 18 years, who received an index PDE5i prescription between January 1999 and June 2008 and with a continuous medical history (≥ 60 months) before the index prescription were included. Primary end-points were the prevalence of underlying disease prior to the index prescription and to establish the detection rate, defined as cumulative incidence of such a diagnosis in the 3 months following the index prescription. Assessments included comparison with age-matched controls, comparison with identical time periods immediately before and 1 year after, index prescription, and changes over time during the study period. Descriptive statistics, analysis of proportions and multivariate logistic regression analysis were used.

RESULTS

Among the 24,708 patients receiving a PDE5i, the prevalence of any underlying diagnosis before the index prescription was 70.23%; prevalence of vasculogenic disease was highest (48.20%). The detection rate of any underlying disease was 11.53%, and again highest for vasculogenic disease (4.07%). Compared with an age-matched control population, the additional detection rate of an unknown underlying disease at PDE5i prescription was 45 for hypertension, 61 for hypercholesterolaemia, 38 for diabetes and 5 for hypogonadism per 10,000 men.

CONCLUSION

Only a minority of men with erectile dysfunction have a previously undiagnosed important underlying disease that is uncovered at the time of an initial PDE5i prescription by a GP.

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.

Hydrogen sulfide and erectile function: a novel therapeutic target

Hydrogen sulfide (H(2)S) is a gaseous transmitter involved in the control of vascular homeostasis. H(2)S is formed endogenously from L-cysteine or L-methionine by two enzymes, cystathionine beta-synthase (CBS) and cystathionine gamma-lyase (CSE), and normally circulates in blood. Studies from the past few years have demonstrated the involvement of H(2)S in erectile mechanisms in animal and human tissues. Exogenous H(2)S relaxes human and animal tissues in vitro and increases intracavernous pressure in experimental animal models. Electrical field stimulation studies on animal and human tissues have demonstrated that endogenous H(2)S is involved in the physiological control of penile tone. In humans, both CBS and CSE are widely expressed on trabecular muscle, implying that the smooth muscle component is the major source of H(2)S. Thus, the L-cysteine-H(2)S pathway may represent a promising target for development of new therapeutics for erectile dysfunction.

New classification of anomalous venous drainage using caverno-computed tomography in men with erectile dysfunction

INTRODUCTION

Venous leak evaluation remains a challenge in many ED patients. Adequate anatomical evaluation may help with optimizing therapeutic strategies.

AIM

Propose a new classification of venous leakage using multidetector computed tomography (MDCT) cavernography, after contrast media intracavernous injection (ICI), under pharmacological stimulation.

METHODS

Thirty-eight patients gave informed consent for the study: 34 complained of ED, unsatisfied with treatment and suspected to have cavernovenous leak; four having morphological anomalies and needing surgery. Patient's clinical history, including age, vascular risk factors, penile nitric oxide release test, Doppler ultrasound and previous treatments were evaluated. MDCT consisted in: 1-ICI of 1 mL of vasoactive medications containing papaverine, chlorydrate (20 mg), urapidil chlorydrate (2.75 mg) and alprostadil (10 mcg); 2-ICI of 20-60 cc of diluted contrast media (1/3) using 20 cc of Ioprimide (300 mg/mL); 3-Spiral MDCT acquisition and three-dimensional volume rendering.

MAIN OUTCOMES MEASURES

Erection degree was assessed using the erection hardness score (EHS); venous drainage was analyzed and deep, superficial veins (SVs), and caverno-spongious communications identified. MDCT findings were compared with clinical data.

RESULTS

The deep dorsal vein (DDV) was opacified in 58% of patients and the SV in 50%. Cavernospongious communications were visible in 18.4%. Sixteen percent presented no visible drainage. A new classification of venous drainage anomalies is proposed: A-No visible drainage (N = 8); B-DDV and preprostatic plexus opacification (N = 11); C-Exclusive SV opacification (N = 10); D-Opacification of both SV and DDV (N = 9). All patients (with one exception) in group A quoted 4 at the EHS vs. none in the others groups (P < 0.0001, exact Fisher test). One patient in group A needed venous drainage due to prolonged erection.

CONCLUSIONS

MDCT after ICI contrast media was able to differentiate between various venous pathways in men with venous origin ED, leading to a new anatomical classification. Absence of leakage was associated with normal erection under pharmacological stimulation.

The effect of non-dipper pattern of hypertension on erectile dysfunction

BACKGROUND

The purpose of this study was to evaluate the relationship between erectile dysfunction (ED) and non-dipper pattern in hypertensive patients.

METHODS

A total of 750 consecutive patients with essential hypertension, who had been evaluated with ambulatory BP monitoring, were screened for this study. One hundred and thirty-two male patients (age range 28-54 years) who had fulfilled the inclusion and exclusion criteria were included in the final analysis. Dipper and non-dipper patterns were detected and sexual function was assessed by the self-administered questionnaire of the International Index of Erectile Function (IIEF).

RESULTS

There was no significant difference between the two groups regarding the number of medications taken and the proportion of each class of antihypertensive medications. Mean age, body mass index, lipid profiles, rate of smoking were similar between the two groups. IIEF score was significantly higher in non-dippers than dippers (p= 0.009). Non-dipping was also found to be an independent determinant for ED.

CONCLUSION

The result of the present study further suggests that non-dipping is a risk indicator for early deterioration of erectile function in hypertensive patients.

Nitric oxide-induced vasorelaxation in response to PnTx2-6 toxin from Phoneutria nigriventer spider in rat cavernosal tissue

INTRODUCTION

Priapism is one of several symptoms observed in accidental bites by the spider Phoneutria nigriventer. The venom of this spider is comprised of many toxins, and the majority has been shown to affect excitable ion channels, mainly sodium (Na(+) ) channels. It has been demonstrated that PnTx2-6, a peptide extracted from the venom of P. nigriventer, causes erection in anesthetized rats and mice.

AIM

We investigated the mechanism by which PnTx2-6 evokes relaxation in rat corpus cavernosum.

MAIN OUTCOME MEASURES

PnTx2-6 toxin potentiates nitric oxide (NO)-dependent cavernosal relaxation.

METHODS

Rat cavernosal strips were incubated with bretylium (3 × 10(-5) M) and contracted with phenylephrine (PE; 10(-5) M). Relaxation responses were evoked by electrical field stimulation (EFS) or sodium nitroprusside (SNP) before and after 4 minutes of incubation with PnTx2-6 (10(-8) M). The effect of PnTx2-6 on relaxation induced by EFS was also tested in the presence of atropine (10(-6) M), a muscarinic receptor antagonist, N-type Ca(2+) channel blockers (ω-conotoxin GVIA, 10(-6) M) and sildenafil (3 × 10(-8) M). Technetium99m radiolabeled PnTx2-6 subcutaneous injection was administrated in the penis.

RESULTS

Whereas relaxation induced by SNP was not affected by PnTx2-6, EFS-induced relaxation was significantly potentiated by this toxin as well as PnTx2-6 plus SNP. This potentiating effect was further increased by sildenafil, not altered by atropine, however was completely blocked by the N-type Ca(2+) channels. High concentrated levels of radiolabeled PnTx2-6 was specifically found in the cavernosum tissue, suggesting PnTx2-6 is an important toxin responsible for P. nigriventer spider accident-induced priapism.

CONCLUSION

We show that PnTx2-6 slows Na(+) channels inactivation in nitrergic neurons, allowing Ca(2+) influx to facilitate NO/cGMP signalling, which promotes increased NO production. In addition, this relaxation effect is independent of phosphodiesterase enzyme type 5 inhibition. Our data displays PnTx2-6 as possible pharmacological tool to study alternative treatments for erectile dysfunction.

Increased risk of stroke among men with erectile dysfunction: a nationwide population-based study

INTRODUCTION

Previous cross-sectional studies have suggested that erectile dysfunction (ED) represents an independent risk factor for future cardiovascular events. However, very few studies have attempted to examine the association between ED and subsequent stroke.

AIM

The aim of this study is to estimate the risk of stroke during a 5-year follow-up period after the first ambulatory care visit for the treatment of ED using nationwide, population-based data and a retrospective case-control cohort design in Taiwan.

METHODS

This study used data sourced from the "Longitudinal Health Insurance Database." The study cohort comprised 1,501 patients who received a principal diagnosis of ED between 1997 and 2001 and 7,505 randomly selected subjects as the comparison cohort. Each patient (N = 9,006) was then individually tracked for 5 years from their index ambulatory care visit to identify those who had diagnosed episodes of stroke.

MAIN OUTCOME MEASURE

Stratified Cox proportional hazard regressions were performed as a means of comparing the 5-year stroke-free survival rate for the two cohorts.

RESULTS

Of the sampled patients, 918 (10.2%) developed stroke within the 5-year follow-up period, that is, 188 individuals (12.5% of the patients with ED) from the study cohort and 730 individuals (9.7% of patients in the comparison cohort) from the comparison cohort. The log-rank test indicated that patients with ED had significantly lower 5-year stroke-free survival rates than those in the comparison cohort (P < 0.001). After adjusting for the patient's monthly income, geographical location, hypertension, diabetes, coronary heart disease, peripheral vascular disease, atrial fibrillation, and hyperlipidemia, patients with ED were more likely to have a stroke during the 5-year follow-up period than patients in the comparison cohort (hazard ratio = 1.29, 95% confidence interval = 1.08 - 1.54, P < 0.01).

CONCLUSIONS

These results suggest that ED is a surrogate marker for future stroke in men.

Erectile dysfunction and risk of clinical cardiovascular events: a meta-analysis of seven cohort studies

INTRODUCTION

For many years, erectile dysfunction (ED) has been considered as a complication of cardiovascular disease (CVD) or regarded as a late consequence of generalized arterial disease. However, a growing body of evidence suggests that ED is an early manifestation of atherosclerosis and a precursor to systemic vascular disease.

AIM

We conducted a meta-analysis to evaluate the association between ED and the risk of CVD events.

METHODS

Relevant studies published between January 1966 and September 2009 were identified by searching Medline, Embase, and The Cochrane Library. Studies were selected using a prior defined criteria. The strength of the relationship between ED and CVD events was assessed by adjusted relative risks (RRs).

MAIN OUTCOME MEASURES

The adjusted RRs of CVD events.

RESULTS

A total of 45,558 participants from seven cohort studies (eight full-text articles) were identified in this meta-analysis. The studies provided adjusted RRs estimates for ED subjects comparing with health subjects, leading to a pooled adjusted RR of 1.47 (95% confidence interval [CI], 1.29-1.66, P < 0.001; P for heterogeneity = 0.152; I(2)  = 36.2%) for CVD events. The risks of CVD, all-cause mortality and myocardial infarction were 1.41 (95% CI, 1.22-1.64 P < 0.001), 1.23 (95% CI, 1.02-1.48; P = 0.034), and 1.43 (95% CI, 1.10-1.85 P = 0.007), respectively. The overall adjusted RR decreased significant from 1.63 (<7 years) to 1.37 (≥ 7 years) along with the elongation of follow-up.

CONCLUSIONS

There is evidence of an increased risk of CVD events for patients with ED. Patients who are discovered to have ED are supposed to be thoroughly assessed for cardiovascular risk and occult systemic vascular disease.

Nebivolol dilates human penile arteries and reverses erectile dysfunction in diabetic rats through enhancement of nitric oxide signaling

INTRODUCTION

Traditional beta-blockers have sometimes been associated with erectile dysfunction (ED). Nebivolol is a cardioselective β(1)-adrenoceptor antagonist that promotes vasodilation through a nitric oxide (NO)-dependent mechanism.

AIM

We evaluated the effects of nebivolol on the NO/cyclic guanosine monophosphate (cGMP) signaling pathway, on erectile function and dysfunction, and in human penile vascular tissues.

METHODS

Erectile response to cavernosal nerve electrical stimulation in control and diabetes-induced ED rats were evaluated, along with serum nitrite/nitrate (NOx) concentration and plasma/tissue cGMP levels. Endothelium-dependent and sildenafil-induced relaxation of isolated human corpus cavernosum (HCC) and human penile resistance arteries (HPRA) were also determined.

MAIN OUTCOME MEASURES

The effects of nebivolol on erectile function and dysfunction and on NO/cGMP-mediated responses.

RESULTS

Treatment with nebivolol significantly potentiated erectile response in control rats, regardless of its effects on blood pressure. Nebivolol increased NOx and plasma cGMP by 3-fold and 2.75-fold, respectively, and significantly augmented the elevation of plasma cGMP produced by sildenafil. Nebivolol enhanced endothelium-dependent and sildenafil-induced relaxations of HCC tissue, and produced endothelium-dependent vasodilation of HPRA. Nebivolol, but not atenolol, significantly improved erectile response in diabetic rats (51.6%, 53.2%, and 87.1% of response at 3 Hz in nondiabetic rats, for vehicle-treated, atenolol-treated, and nebivolol-treated diabetic rats, respectively); after sildenafil administration, ED was completely reversed in nebivolol-treated diabetic rats (69.6% and 112% for diabetic rats treated with sildenafil and nebivolol plus sildenafil, respectively). Accordingly, nebivolol restored systemic NOx levels and cGMP content in penile tissue from these animals.

CONCLUSIONS

Nebivolol in vivo activated the NO/cGMP pathway, enhanced erectile response and reversed ED in diabetic rats. Moreover, nebivolol in vitro potentiated NO/cGMP-mediated relaxation of human erectile tissues. These effects may account for the low incidence of ED in nebivolol-treated hypertensive patients. Nebivolol therefore may have utility in the treatment of ED, particularly ED associated with diabetes.

Plasma Chitotriosidase Activity and Arteriogenic Erectile Dysfunction: Association with the Presence, Severity, and Duration

Introduction. Plasma chitotriosidase (ChT) activity is associated with the presence of atherosclerosis and is a new cardiovascular risk marker. Although available evidence supports its role in atherogenesis, there is a lack of an obvious correlation between plasma ChT activity and erectile dysfunction (ED). Aim. Our aim was to investigate the association of the level of serum ChT activity with ED. Main Outcome Measures. Erectile function was assessed using Sexual Health Inventory for Men (SHIM). Serum fasting lipid profile (plasma total cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol, and triglycerides); sex hormones (luteinizing hormone, follicle-stimulating hormone, prolactin, total testosterone, and estradiol); and thyroid-stimulating hormone were measured. Plasma ChT activity, as well as K(m), V(max), optimum pH, and heat stability of the ChT were also assessed. Penile duplex ultrasound examination before and after intracavernous injection of 20 microg prostaglandin E1 (PGE(1)), pudendal nerve conduction tests and sensory-evoked potential studies were done to identify patients with arteriogenic ED. Intima-media thickness (IMT) and plaque formation of common carotid artery were determined bilaterally using B-mode ultrasonography. Methods. A total of 124 normolipidemic patients with ED and 120 healthy controls were recruited for this study. Results. Serum ChT activity in patients with ED (116 +/- 18 nmol/h/mL) was significantly higher than in normal control subjects (51 +/- 12 nmol/h/mL) (P < 0.001). There was a significant positive correlation between plasma ChT activity and (i) severity of ED and (ii) duration of ED (r = 0.68, P = 0.004; and r = 0.62, P = 0.01 respectively).We also found that all ChT kinetic parameters assessed (K(m), V(max), and optimum pH) in plasma of ED patients were significantly different from those of normal controls (all P < 0.001). The results of heat stability analysis, demonstrated that plasma ChT activity in the normal individuals was more stable than in the patients with arteriogenic ED (P < 0.001). A significant correlation was seen between the plasma ChT activity and the mean common carotid IMT (r = 0.78, P = 0.002). Moreover, a significant correlation was seen between the severity of ED and mean common carotid IMT (r = 0.74, P = 0.003). We did not address chitotriosidase genotype. Conclusions. Our results indicate that plasma ChT activity is increased in normolipidemic patients with arteriogenic ED, suggesting its possible role in the pathophysiology of arteriogenic ED. The clinical significance of this increase should be assessed in further studies. Safarinejad MR, and Safarinejad SH. Plasma chitotriosidase activity and arteriogenic erectile dysfunction: Association with the presence, severity, and duration. J Sex Med **;**:**-**.

The association of glomerular filtration rate and erectile dysfunction with severity of coronary artery disease in patients presenting with chest pain

BACKGROUND

The most common cause of death in patients with chronic kidney disease is cardiovascular. Coexistence of reduced estimated glomerular filtration rate (eGFR) and erectile dysfunction (ED) may predate severe underlying coronary artery disease (CAD). The aim of this study was to evaluate the predictive value of presence and severity of ED and reduced estimated eGFR in the risk stratification of CAD in patients with chest pain.

METHODS

Two hundred and sixty-five consecutive male patients with chest pain were included. All patients underwent exercise stress test (EST), of whom those with positive EST underwent coronary angiography. eGFR was calculated and sexual health inventory for men (SHIM) form was applied to evaluate ED. The relation between SHIM scores, eGFR and the number of arteries with significant lesions was evaluated.

RESULTS

Of the 265 male patients, 105 had positive EST while the remaining 160 patients had negative EST. ED was present in 62 patients (38.8%) in the EST (-) group and in 64 patients (61%) in the EST (+) group (P = 0.000). In the EST (+) group, coronary angiography (CAG) revealed normal coronary anatomy or insignificant coronary lesions in 19 (18%), one-vessel disease in 45 (43%), two-vessel disease in 22 (21%) and three-vessel disease in 19 (18%) patients, respectively. The lowest ED prevalence (36.8%) was seen in patients who had normal coronary anatomy or insignificant coronary lesions while the highest prevalence was in those with three-vessel disease (89.5%). When eGFR were taken into account, there was a significant difference between the groups as well (107.2 ± 19.2 ml/min in the EST (-) group versus 94.1 ± 20.0 ml/min in the EST (+) group; P = 0.001).

CONCLUSION

The presence and severity of ED and reduced eGFR are associated with the severity of underlying CAD in patients presenting with chest pain, and they could be implemented in the risk stratification of these patients.

Erectile dysfunction as a predictor for subsequent atherosclerotic cardiovascular events: findings from a linked-data study

INTRODUCTION

In spite of the mounting interest in the nexus between erectile dysfunction (ED) and cardiovascular (CV) diseases, there is little published information on the role of ED as a predictor for subsequent CV events.

AIM

This study aimed to investigate the role of ED as a predictor for atherosclerotic CV events subsequent to the manifestation of ED. Method. The investigation involved the retrospective study of data on a cohort of men with ED linked to hospital morbidity data and death registrations. By using the linked data, the incidence rates of atherosclerotic CV events subsequent to the manifestation of ED were estimated in men with ED and no atherosclerotic CV disease reported prior to the manifestation of ED. The risk of subsequent atherosclerotic CV events in men with ED was assessed by comparing these incidence rates with those in the general male population.

MAIN OUTCOME MEASURE

Standardized incidence rate ratio (SIRR), comparing the incidence of atherosclerotic CV events subsequent to the manifestation of ED in a cohort of 1,660 men with ED to the incidence in the general male population.

RESULTS

On the basis of hospital admissions and death registrations, men with ED had a statistically significantly higher incidence of atherosclerotic CV events (SIRR 2.2; 95% confidence interval 1.9, 2.4). There were significantly increased incidence rate ratios in all age groups younger than 70 years, with a statistically highly significant downward trend with increase of age (P < 0.0001) across these age groups. Younger age at first manifestation of ED, cigarette smoking, presence of comorbidities and socioeconomic disadvantage were all associated with higher hazard ratios for subsequent atherosclerotic CV events.

CONCLUSIONS

The findings show that ED is not only significantly associated with but is also strongly predictive of subsequent atherosclerotic CV events. This is even more striking when ED presents at a younger age.