ANTIHYPERTENSIVE DRUGS INDUCE STRUCTURAL REMODELING OF THE PENILE VASCULATURE

Review of the current information on erectile dysfunction in hypertensive males with 40 years of age or older

Hypertension (HT) is a prevalent disease, which origin frequently remains undetermined. Antihypertensive treatment (AHT) has been linked with erectile dysfunction (ED), mainly in middle-aged and older males. On the other side, some drugs used in AHT seem to be themselves associated with ED as a secondary effect. This led to the search of coadjuvant therapies for hypertensive patients with ED, considering that both illnesses cause high physical, psychological and economic burden. While the association between AHT and ED has been approached several times, the direct association between blood pressure and ED remains unclear. This review aims to summarize the current knowledge on the relationship between HT, AHT and ED specifically in males with age ≥40 years.

A prospective study of the effect of antihypertensive medications on the sexual functions of hypertensive adult male patients

Background:

The potential for antihypertensive medications to produce deleterious adverse effects on sexual functions among hypertensive adult male patients has been widely reported, such adverse effects may limit drug adherence and compliance.

Aim:

The aim of this study was to assess the effect of antihypertensive medication use on sexual functions among hypertensive adult male patients.

Methodology:

The study was carried out at the outpatient clinic of a Nigerian University Teaching Hospital. A total of one hundred and fifty-nine recruited hypertensive adult male patients that were being managed at the center over a 3-month period between January 2017 and April 2017 participated in the study; provided they satisfied the inclusion and exclusion criteria for enrolment.

Results:

The respondents were between 30 and 98 years of age, (mean of 59 ± 11.1 years). Blood pressure recorded was during their initial medical diagnosis for hypertension. Systolic blood pressure recorded was between 128 and 194 mmHg (mean of 162 ± 16.4 mmHg), while their diastolic blood pressure was between 78 and 120 mmHg (mean of 95 ± 10.7 mmHg). The highest occurrence of sexual dysfunctions was associated with calcium-channel blockers in 32 (20.1%) patients, followed by diuretics in 27 (17.0%) and, angiotensin-converting enzyme inhibitors in 20 (12.6%) patients.

Conclusion:

Calcium channel blockers caused the highest occurrence of sexual dysfunctions.

This prospective study assessed the effect of antihypertensive medications on sexual functions among hypertensive adult male patients attending the medical outpatient clinic of a Nigerian University Teaching Hospital. A total of 159 patients who consented to the study and had been attending the clinic regularly for at least 6-month were enrolled. The respondents aged 30–98 years (mean 59 ± 11.1 years). Antihypertensive medication-associated sexual dysfunctions among the patients were observed in descending order as follows: calcium channel blockers in 32 (20.1%), diuretics in 27 (17.0%), Angiotensin converting enzyme inhibitors in 20 (12.6%), centrally acting antihypertensives in 11 (6.9%), beta receptor blockers in 8 (5.0%), vasodilators in 2 (1.3%), combined alpha- and beta-receptor blockers in 2 (1.3%) and alpha receptor blockers in 1 (0.6%). Antihypertensive medical prescriptions should reflect a balance between efficacy and tendency to cause sexual dysfunctions.

Haemorrhoids are associated with erectile dysfunction: a population-based study

Haemorrhoids are associated with regional vascular abnormalities and rectal pain, which are hypothesized to increase the risk of erectile dysfunction (ED); however, few studies have investigated the association between ED and haemorrhoids. This case-control study aimed to estimate the association between haemorrhoids and ED by using a population-based data in Taiwan. We identified 6,310 patients with ED as cases and randomly selected 31,550 controls. Conditional logistic regression was performed to compute the odds ratio (OR) for having been previously diagnosed with haemorrhoids between cases and controls. The results show that haemorrhoids were found to be present among 1,572 (24.9%) cases and 4,491 (14.20%) controls. The OR for prior haemorrhoids among cases was 1.90 (95% CI = 1.78-2.03) when compared with controls after adjusting for monthly income, geographical location, hypertension, diabetes, coronary heart disease, hyperlipidemia, obesity and alcohol abuse/alcohol dependence syndrome. Younger cases demonstrated a higher risk for prior haemorrhoids when compared with controls. In particular, the adjusted OR among cases <30 years old was 3.71 (95% CI = 2.74-5.02) when compared with controls. We concluded that there was an association between ED and a prior diagnosis of haemorrhoids.

Hyperthyroidism and erectile dysfunction: a population-based case-control study

Dysthyroidism has been highlighted as a common endocrine disorder associated with erectile dysfunction (ED); however, to date, no large-scale population-based study has investigated the association between hyperthyroidism and ED. This case-control study aimed to explore the association between ED and hyperthyroidism using a population-based data set. In total, 6310 adult patients who received new diagnoses of ED were recruited as cases together with 18 930 matched enrollees with no history of ED who served as controls. Conditional logistic regressions were conducted to explore the association between ED and having been previously diagnosed with hyperthyroidism. In total, 569 (2.3%) of the 25 240 sampled subjects had been diagnosed with hyperthyroidism before the index date; hyperthyroidism was found in 207 (3.3%) cases and 362 (1.90%) controls. After adjusting for potential confounding factors, the odds ratio (OR) of prior hyperthyroidism among cases was 1.64 (95% confidence interval=1.37-1.96, P<0.001) than that of controls. No association was detected between prior hyperthyroidism and ED for the 18-30, 30-39 and >70 age groups. Subjects aged between 60 and 69 years had the highest ORs for prior hyperthyroidism among cases when compared to controls (OR=1.84; 95% confidence interval=1.20-2.84; P<0.001). Our study further confirms the existence of an association between ED and prior hyperthyroidism.

Varicocele is associated with erectile dysfunction: a population-based case-control study

INTRODUCTION

While many studies have been conducted investigating the efficacy of varicocele treatment on fertility, the literature is comparatively sparse concerning the association between varicocele, varicocelectomy, and erectile dysfunction (ED).

AIM

This study aimed to estimate the associations between varicocele, varicocelectomy, and ED using a population-based dataset.

METHODS

This study used data from the Longitudinal Health Insurance Database 2000 in Taiwan. A total of 32,856 cases and 98,568 randomly selected controls were included in this study. Conditional logistic regression analyses were used to examine associations between ED and having been previously diagnosed with varicocele or having underwent a varicocelectomy.

MAIN OUTCOME MEASURE

The odds of prior varicocele or having underwent a varicocelectomy between cases and controls.

RESULTS

Of the sampled patients, the prevalence of prior varicocele was 3.3% and 1.2% for cases and controls, respectively (P < 0.001). Conditional logistic regression analysis suggested that the odds ratio (OR) of being previously diagnosed with varicocele for cases was 3.09 (95% confidence interval [CI] = 2.67-3.49) when compared with controls after adjusting for monthly income, geographic location, hypertension, diabetes, coronary heart disease, hyperlipidemia, hypogonadism, obesity, and alcohol abuse/alcohol dependence syndrome. Furthermore, cases were 1.92 (95% CI = 1.52-2.43) times more likely to have undergone a varicocelectomy than controls. Furthermore, subjects aged between 18 and 29 had the highest ORs for prior varicocele among cases when compared with controls (OR = 5.20; 95% CI = 3.27-8.28).

CONCLUSION

This investigation succeeded in identifying an association between both varicocele and ED. We also realized that varicocele patients who underwent a varicocelectomy had lower magnitudes of association with ED than those who did not.

Migraine and erectile dysfunction: Evidence from a population-based case-control study

Background: This case-control study aimed to estimate the association between erectile dysfunction (ED) and migraines using a nationwide population-based database in Taiwan.

Methods: The data used for this matched case-control study were retrieved from the Taiwan Longitudinal Health Insurance Database 2000. We identified 5763 patients with ED as the cases and randomly selected 17,289 patients as the controls. Conditional logistic regression was used to calculate the odds ratios (OR) for prior migraine between cases and controls.

Results: After adjusting for hypertension, diabetes, hyperlipidaemia, renal disease, coronary heart disease, obesity, and alcohol abuse/alcohol dependence syndrome, conditional logistic regression revealed that among ED patients the odds of having been previously diagnosed with migraines was 1.63 (95% CI, 1.39–1.91) that of the control group. This risk was more pronounced in younger groups, with the highest risk being detected among those aged between 30 and 39 years. After adjusting for the above mentioned comorbidities, ED patients aged between 30 and 39 years were found to be at 1.98 (95% CI, 1.67–2.23) times the risk of controls for having been previously diagnosed with migraines.

Conclusion: We conclude that ED is associated with having been previously diagnosed with migraines, particularly in younger populations.

Mechanisms of penile erection and basis for pharmacological treatment of erectile dysfunction

Erection is basically a spinal reflex that can be initiated by recruitment of penile afferents, both autonomic and somatic, and supraspinal influences from visual, olfactory, and imaginary stimuli. Several central transmitters are involved in the erectile control. Dopamine, acetylcholine, nitric oxide (NO), and peptides, such as oxytocin and adrenocorticotropin/α-melanocyte-stimulating hormone, have a facilitatory role, whereas serotonin may be either facilitatory or inhibitory, and enkephalins are inhibitory. The balance between contractant and relaxant factors controls the degree of contraction of the smooth muscle of the corpora cavernosa (CC) and determines the functional state of the penis. Noradrenaline contracts both CC and penile vessels via stimulation of α₁-adrenoceptors. Neurogenic NO is considered the most important factor for relaxation of penile vessels and CC. The role of other mediators, released from nerves or endothelium, has not been definitely established. Erectile dysfunction (ED), defined as the "inability to achieve or maintain an erection adequate for sexual satisfaction," may have multiple causes and can be classified as psychogenic, vasculogenic or organic, neurologic, and endocrinologic. Many patients with ED respond well to the pharmacological treatments that are currently available, but there are still groups of patients in whom the response is unsatisfactory. The drugs used are able to substitute, partially or completely, the malfunctioning endogenous mechanisms that control penile erection. Most drugs have a direct action on penile tissue facilitating penile smooth muscle relaxation, including oral phosphodiesterase inhibitors and intracavernosal injections of prostaglandin E₁. Irrespective of the underlying cause, these drugs are effective in the majority of cases. Drugs with a central site of action have so far not been very successful. There is a need for therapeutic alternatives. This requires identification of new therapeutic targets and design of new approaches. Research in the field is expanding, and several promising new targets for future drugs have been identified.

Impact of systemically active neurohumoral factors on the erectile response of the rat

INTRODUCTION

Mean arterial pressure (MAP) and specific regulation of penile blood flow are the primary determinants of an erection. While this concept is well recognized, the differential relationship between systemically acting vasoactive factors on arterial pressure and erectile responses is not well described.

AIM

The aim of this study was to determine how the modification of systemic levels of neurohumoral factors impacts on the magnitude and efficiency of the erectile response.

MAIN OUTCOME MEASURES

The main outcome measures for this study are changes in MAP and intracavernosal pressure (ICP) following electrostimulation of the cavernous nerve.

METHODS

Anesthetized adult, male Sprague-Dawley rats were catheterized for measuring MAP (carotid), ICP, and drug administration (vena cava). Erections were induced via cavernous nerve electrostimulation. Vasoactive drug infusions were used to produce changes in MAP levels including: hexamethonium, angiotensin II (ANGII)±hexamethonium, methoxamine±hexamethonium, losartan, MAHMA NONOate, and terbutaline.

RESULTS

In general, ICP and MAP were linearly correlated regardless of treatment. Hexamethonium markedly dropped MAP and proportionately decreased the magnitude of the erectile response. ANGII or methoxamine given to hexamethonium-pretreated or untreated rats increased MAP similarly, but produced contrasting effects on erectile responses. ANGII-induced pressor responses were associated with increased erectile responses whereas all methoxamine treatments markedly decreased erectile responses. Depressor changes with losartan or terbutaline, but not MAHMA NONOate, also impacted negatively on the efficiency of the erectile responses at lower arterial pressures.

CONCLUSIONS

In general, the magnitude of the erectile responses was found to be dependent upon the level of MAP, although the mechanism by which arterial pressure was changed impacted substantially on the characteristics of the relationship. The major finding was that circulation-wide α-adrenoceptor stimulation was extremely deleterious to erectile responses whereas global stimulation of ANG II receptors was actually proerectile. Overall, the results indicate that neurohumoral specificity in systemic hemodynamic control is also critical in establishing the optimal erectile environment in rats.

Changes critical to persistent lowering of arterial pressure in spontaneously hypertensive rat occur early in antihypertensive treatment

OBJECTIVES

Angiotensin-converting enzyme inhibition (ACEI) in adult spontaneously hypertensive rats (SHRs) produces reductions in mean arterial pressure (MAP) and vascular structure that persist after treatment cessation. This study used an intermittent treatment strategy to determine the time course of changes in MAP, vascular resistance properties, and the tissue levels of endothelin.

METHODS

Adult SHRs were treated with enalapril and low sodium diet for three 2-week treatment cycles, each separated by 2-week washout periods. MAP was measured via radiotelemetry. Hindlimb structurally based vascular resistance properties were assessed after two treatment cycles. Endothelin was measured in mesenteric vessels, renal cortex and medulla in untreated SHR (Con), and at day 10 of the first and third treatment cycles.

RESULTS

Treatment produced a persistent reduction in MAP; however, the magnitude of change in the 'off-treatment' level decreased following successive treatments (cycle 1: -15 ± 1.7%, cycle 2: -8 ± 1.9%, and cycle 3: -1 ± 1.7%). Reduction in hindlimb vascular structure after two cycles of treatment was not different from that previously observed after one cycle. Endothelin levels were significantly elevated during the third cycle in renal medulla (Con: 797 ± 102 pg/g tissue, cycle 1: 767 ± 81 pg/g tissue, cycle 3: 1097 ± 205 pg/g tissue) and mesenteric vessels (Con: 711 ± 226 pg/g tissue, cycle 1: 696 ± 231 pg/g tissue, cycle 3: 1063 ± 741 pg/g tissue). Concomitant treatment with an endothelin antagonist did not impact arterial pressure.

CONCLUSION

These findings demonstrate that during ACEI treatment, most of the changes that confer persistent changes in MAP and vascular structure occur within the first 2 weeks. Elevation in endothelin levels is likely unrelated to arterial pressure.

Anatomy, physiology, and pathophysiology of erectile dysfunction

INTRODUCTION

Significant scientific advances during the past 3 decades have deepened our understanding of the physiology and pathophysiology of penile erection. A critical evaluation of the current state of knowledge is essential to provide perspective for future research and development of new therapies.

AIM

To develop an evidence-based, state-of-the-art consensus report on the anatomy, physiology, and pathophysiology of erectile dysfunction (ED).

METHODS

Consensus process over a period of 16 months, representing the opinions of 12 experts from seven countries.

MAIN OUTCOME MEASURE

Expert opinion was based on the grading of scientific and evidence-based medical literature, internal committee discussion, public presentation, and debate.

RESULTS

ED occurs from multifaceted, complex mechanisms that can involve disruptions in neural, vascular, and hormonal signaling. Research on central neural regulation of penile erection is progressing rapidly with the identification of key neurotransmitters and the association of neural structures with both spinal and supraspinal pathways that regulate sexual function. In parallel to advances in cardiovascular physiology, the most extensive efforts in the physiology of penile erection have focused on elucidating mechanisms that regulate the functions of the endothelium and vascular smooth muscle of the corpus cavernosum. Major health concerns such as atherosclerosis, hyperlipidemia, hypertension, diabetes, and metabolic syndrome (MetS) have become well integrated into the investigation of ED.

CONCLUSIONS

Despite the efficacy of current therapies, they remain insufficient to address growing patient populations, such as those with diabetes and MetS. In addition, increasing awareness of the adverse side effects of commonly prescribed medications on sexual function provides a rationale for developing new treatment strategies that minimize the likelihood of causing sexual dysfunction. Many basic questions with regard to erectile function remain unanswered and further laboratory and clinical studies are necessary.

Sexual dysfunction: the 'prima ballerina' of hypertension-related quality-of-life complications

Sexual dysfunction is currently considered a serious quality-of-life-related health problem, exerting a major impact on patients' and their sexual partners' life. Available data indicate that essential hypertension is a risk factor for sexual dysfunction, as male and female sexual dysfunction is more prevalent in hypertensive patients than normotensive individuals. Several mechanisms have been implicated in the pathogenesis of sexual dysfunction in hypertensive patients, and major determinants include severity and duration of hypertension, age, and antihypertensive therapy. Female sexual dysfunction, although more frequent than its male counterpart, remains largely under-recognized. Older antihypertensive drugs (diuretics, beta-blockers, centrally acting) exert negative results, whereas newer drugs have either neutral (calcium antagonists, angiotensin-converting enzyme inhibitors) or beneficial effects (angiotensin receptor blockers). Erectile dysfunction is related to ischemic heart disease and might be an 'early therapeutic window' of asymptomatic coronary artery disease. It seems of utmost importance for every physician treating hypertensive patients to become familiar with sexual dysfunction (through better education and specific seminars) for the proper management of these patients.

Effects of ACE inhibition and beta-blockade on female genital structures in spontaneously hypertensive rats

INTRODUCTION AND AIM

This study evaluated the possible differences between an angiotensin converting enzyme (ACE) inhibitor and a beta-blocker concerning their potential protective role on female external genitalia in spontaneously hypertensive rats (SHR).

MAIN OUTCOME MEASURES

Morphological changes in the clitoris after antihypertensive treatments.

METHODS

For 6 months, SHR received no treatment; SHR + ramipril (RAM), SHR + atenolol (AT), and control Wistar Kyoto (WKY) rats received no treatment. Clitorises were processed for immunohistochemistry using anti-alpha-smooth muscle actin (alpha-SMA), anti-collagen I and III, anti-transforming growth factor beta(1) (TGFbeta(1)), and anti-endothelial nitric oxide synthase (eNOS) antibodies.

RESULTS

SHR + RAM and SHR + AT presented significantly lower blood pressure in both groups vs. untreated SHR. Compared with WKY, alpha-SMA was increased in the arteries and in the cavernous spaces of the clitoris together with a marked increase in wall/lumen ratio in clitoral vessels in untreated SHR. All these alterations were diminished in SHR + AT (P < 0.01). SHR + RAM presented differences with respect to SHR + AT in the reduction of these variables. TGFbeta(1) expression in the vessel wall from the clitoris and collagen I and III deposition in the interstitium from the clitoris in untreated SHR were significantly more (P < 0.01) than in WKY. While SHR + AT showed a mild decrease in these variables, SHR + RAM presented a significant reduction (P < 0.01) in TGFbeta(1) expression interstitial fibrosis and in both types of collagens. Positive immunostaining of eNOS in the sinusoidal endothelium from the clitoris was less (P < 0.01) in untreated SHR (3.4 +/- 1.3%) and SHR + AT (5.1 +/- 1.2%) than in SHR + RAM (17.2 +/- 1.6%) and WKY (15.9 +/- 1.7%). Untreated SHR and SHR + AT presented more surrounding connective tissue at the perineurium in the clitoris (P < 0.01) than SHR + RAM.

CONCLUSION

ACE inhibition provided a considerable protective role on the female external genitalia structures in SHR by a mechanism that may be, at least in part, independent of the degree of blood pressure lowering.

Evidence that the vasodilator angiotensin-(1-7)-Mas axis plays an important role in erectile function

The vasodilator/antiproliferative peptide angiotensin-(1-7) [ANG-(1-7)] is released into the corpus cavernosum sinuses, but its role in erectile function has yet to be defined. In this study, we sought to determine whether ANG-(1-7) and its receptor Mas play a role in erectile function. The ANG-(1-7) receptor Mas was immunolocalized in rat corpus cavernosum by confocal microscopy. Infusion of ANG-(1-7) into corpus cavernosum at a rate of 15.5 pmol x kg(-1) x min(-1) potentiated the elevation of the corpus cavernosum pressure induced by electrical stimulation of the major pelvic ganglion (MPG) in rats. The facilitatory effect of ANG-(1-7) was completely blunted by the specific ANG-(1-7) receptor blocker A-779 and N(omega)-nitro-L-arginine methyl ester. Nitric oxide (NO) release in the corpus cavernosum was evaluated with the fluorescent dye 4-amino-5 methylamino-2',7'-difluorofluorescein diacetate. Electrical stimulated-release of NO in rat corpus cavernosum was potentiated by ANG-(1-7). Furthermore, incubation of rat and mouse corpus cavernosum strips with ANG-(1-7) at 10 nmol/l resulted in an increase of NO release. This effect was completely abolished in mas-deficient mice. More importantly, genetic deletion of Mas resulted in compromised erectile function as demonstrated by penile fibrosis and severely depressed response to electrical stimulation of the MPG. Furthermore, the attenuated erectile function of DOCA-salt hypertensive rats was fully restored by ANG-(1-7) administration. Together these data provide strong evidence for a key role of the ANG-(1-7)-Mas axis in erectile function.

Sexual function in hypertensive patients receiving treatment

In many forms of erectile dysfunction (ED), cardiovascular risk factors, in particular arterial hypertension, seem to be extremely common. While causes for ED are related to a broad spectrum of diseases, a generalized vascular process seems to be the underlying mechanism in many patients, which in a large portion of clinical cases involves endothelial dysfunction, ie, inadequate vasodilation in response to endothelium-dependent stimuli, both in the systemic vasculature and the penile arteries. Due to this close association of cardiovascular disease and ED, patients with ED should be evaluated as to whether they may suffer from cardiovascular risk factors including hypertension, cardiovascular disease or silent myocardial ischemia. On the other hand, cardiovascular patients, seeking treatment of ED, must be evaluated in order to decide whether treatment of ED or sexual activity can be recommended without significantly increased cardiac risk. The guideline from the first and second Princeton Consensus Conference may be applied in this context. While consequent treatment of cardiovascular risk factors should be accomplished in these patients, many antihypertensive drugs may worsen sexual function as a drug specific side-effect. Importantly, effective treatment for arterial hypertension should not be discontinued as hypertension itself may contribute to altered sexual functioning; to the contrary, alternative antihypertensive regimes should be administered with individually tailored drug regimes with minimal side-effects on sexual function. When phosphodiesterase-5 inhibitors, such as sildenafil, tadalafil and vardenafil, are prescribed to hypertensive patients on antihypertensive drugs, these combinations of antihypertensive drugs and phosphodiesterase 5 are usually well tolerated, provided there is a baseline blood pressure of at least 90/60 mmHg. However, there are two exceptions: nitric oxide donors and α-adrenoceptor blockers. Any drug serving as a nitric oxide donor (nitrates) is absolutely contraindicated in combination with phosphodiesterase 5 inhibitors, due to significant, potentially life threatening hypotension. Also, α-adrenoceptor blockers, such as doxazosin, terazosin and tamsulosin, should only be combined with phosphodiesterase 5 inhibitors with special caution and close monitoring of blood pressure.

Valsartan treatment reverses erectile dysfunction in diabetic rats

In order to investigate the effect of angiotensin receptor blockage (ARB) for the treatment on diabetic erectile dysfunction (ED), we used male Sprague-Dawley rats injected with 65 mg/kg streptozotocin to induce diabetes mellitus. The diabetic rats with ED were selected by hypodermic injection of apomorphine (APO) after 8 weeks of model setting. All rats were divided into four groups: G1 (normal control rats), G2 (diabetic rats treated with normal saline), G3 (diabetic rats treated with valsartan) and G4 (diabetic rats treated with spironolactone). After treatment with drugs for 8 weeks, the rate of erection for each group was evaluated after the injection of APO. The intracavernous pressure (ICP) of each rat was then recorded before and after the electrostimulation of the major pelvic ganglion. The rates of erection and the ICP after electrostimulation for diabetic rats treated with valsartan were significantly higher than that in diabetic rats treated with normal saline and spironolactone. The ARB may be an effective therapy for diabetics with ED.

Increased intracavernosal pressure response in hypertensive rats after chronic hemin treatment

INTRODUCTION

Erectile dysfunction (ED) is increased in prevalence in patients with arterial hypertension. Whether upregulation of heme oxygenase (HO) expression could improve penile erection has been unknown.

AIMS

To correlate altered expression profiles of HO-1 and soluble guanylyl cyclase (sGC) in penile tissues with low intracavernosal pressure (ICP) in adult spontaneously hypertensive rats (SHR); and to investigate therapeutic effect of hemin-induced upregulation of HO-1 in penile tissues on ED developed in adult SHR.

METHODS AND MAIN OUTCOME MEASURES

Intracavernosal pressure changes after electrical stimulation were monitored in adult SHR and age-matched normotensive Sprague-Dawley (SD) rats after chronic administration of either hemin or hydralazine. Expression levels of HO-1, HO-2, sGC, and phosphodiesterase type 5 (PDE5) were examined with Western blot.

RESULTS

Frequency-dependent ICP changes were reduced in adult SHR. Three weeks after hemin treatment, high blood pressure of SHR was normalized and ICP responses to electrical stimulations in SHR were significantly increased to the level of normotensive rats. Hydralazine-treated SHR had normalized blood pressure but unaltered low ICP response. Expression of HO-1 and sGC was upregulated and that of PDE5 downregulated in hemin-treated, but not hydralazine-treated, SHR.

CONCLUSIONS

Decreased erectile responses in adult SHR can be improved through chronic hemin treatment. Prolonged upregulation of HO-1 and sGC as well as lowered expression of PDE5 may at least partially explain the effect of hemin treatment on ICP. Upregulation of HO-1 may represent a novel therapeutic approach to treat ED.

Relationship between chronic tadalafil administration and improvement of endothelial function in men with erectile dysfunction: a pilot study

Men with erectile dysfunction (ED) frequently have a disproportionate burden of comorbid vascular disorders including atherosclerotic disease. We investigated whether scheduled tadalafil is better than on-demand (OD) in improving endothelium-dependent vasodilatation of cavernous arteries in men with ED and whether this effect is also exerted on markers of endothelial function. We did an open-label, randomized, crossover study including 20 male outclinic patients aged 18 years or older (mean age 54 years) who had at least a 3-month history of ED of any severity or etiology. Tadalafil (20 mg) on alternate days (ADs) or OD was administered for 4 weeks. Primary end points were variations of basal inflow (peak systolic velocity (PSV)) and flow-mediated dilatation (FMD) of cavernous arteries compared with baseline at penile Duplex ultrasound. Secondary end points were variations of Q13-SIEDY scores regarding morning erections and of markers of endothelial function, that is, vascular cell adhesion molecule (VCAM), intercellular cell adhesion molecule, endothelin-1 (ET-1), insulin and C-reactive protein (CRP). PSVs and FMD were higher after AD treatment when compared with OD and baseline, respectively (P=0.0001), and improvements were maintained from 2 weeks after discontinuation (P<0.005). Patients receiving tadalafil AD experienced a significant improvement of morning erections as compared to AD treatment (P<0.0001); ET1, VCAM and CRP showed a robust decrease after chronic vs OD regimes (P<0.05), with concomitant increase in insulin levels (P<0.05), without any variation in blood pressure and other laboratory parameters. Chronic but not OD tadalafil improves endothelial function with sustained effects from its discontinuation. Chronic treatment also produces a dramatic increase in morning erections, which determines better oxygenation to the penis, thus providing a rationale for vascular rehabilitation.

Physiology of penile erection and pathophysiology of erectile dysfunction

This article reviews the physiology of penile erection, the components of erectile function, and the pathophysiology of erectile dysfunction. The molecular and clinical under-standing of erectile function continues to gain ground at a particularly fast rate. Advances in gene discovery have aided greatly in working knowledge of smooth muscle relaxation/contraction pathways. The understanding of the nitric oxide pathway has aided not only in the molecular understanding of the tumescence but also greatly in the therapy of erectile dysfunction.

Impact of antihypertensive treatments on erectile responses in aging spontaneously hypertensive rats

OBJECTIVE

We previously demonstrated that brief, aggressive antihypertensive therapy recovered erectile function in 40-week-old spontaneously hypertensive rats (SHR). The present study examined the impact of antihypertensive and testosterone treatments on erectile function in aging SHR.

DESIGN AND METHODS

Centrally initiated erections were determined in response to apomorphine throughout. At 30 and 49 weeks, SHR were treated for 2 weeks with enalapril or hydralazine. A third more aggressive treatment (68 weeks) involved enalapril or losartan plus a low salt diet or a triple therapy (hydralazine, nifedipine, hydrochlorothiazide). In a separate study, cross-over kidney transplantations were performed between untreated and losartan-treated SHR. Arterial pressure was assessed post-transplantation using radio-telemetric transducers.

RESULTS

There was an age-related decrease in erections between 30 and 68 weeks (3.1 +/- 0.79 versus 0.2 +/- 0.38) that was not improved by testosterone administration. Early treatment with enalapril or hydralazine did not prevent this decline, although the second treatment resulted in significant improvements (enalapril, 0.8 +/- 0.70; hydralazine, 0.8 +/- 0.41 versus control, 0.3 +/- 0.60). A 2-week aggressive antihypertensive treatment at 68 weeks increased erections approximately two-fold, with the previously treated rats receiving triple therapy having markedly improved erectile responses (0.2 +/- 0.53 versus 1.1 +/- 1.67). In the transplantation study, previously losartan-treated SHR given an untreated kidney had higher arterial pressure but twice the number of erections in comparison with the SHR with lower arterial pressure resulting from transplanting a treated kidney.

CONCLUSIONS

Aggressive antihypertensive treatments may be more beneficial in improving erectile function in aged SHR, via an effect that appears to be tissue specific, and not based on changes in blood pressure.

Prevalence of erectile dysfunction among 7689 patients with diabetes or hypertension, or both

OBJECTIVES

To survey the presence of, and attitudes toward, erectile dysfunction (ED) among patients with hypertension and/or diabetes mellitus who sought general medical care for any reason.

METHODS

The abbreviated five-item version of the International Index of Erectile Function (IIEF-5) was used to determine the presence of ED. A patient questionnaire was used to assess attitudes about ED.

RESULTS

We surveyed 7689 patients (mean +/- SD age 58.9 +/- 9.2 years), including 6719 (87%) in a stable sexual relationship. In patients with hypertension alone (n = 3906) and diabetes alone (n = 2377), ED was reported by 2379 (61%) and 1603 (67%) and was present in 2634 (67%) and 1677 (71%), respectively, as defined by an IIEF-5 score of less than 21. The corresponding mean scores were 12.0 (+/-4.6) and 11.5 (+/-4.6) in patients with ED and 20.5 (+/-3.6) and 20.2 (+/-3.8) in those without ED. Prevalence was affected by disease characteristics and history, and the number and type of antihypertensive medications. ED was reported by 924 (78%) of 1186 patients with both diseases and was present in 917 (77%) according to the IIEF-5 score. Overall, ED was reported by 5063 patients (66%) with hypertension and/or diabetes, was present in 5391 (70%) according to the IIEF-5 score, and increased in prevalence with age. ED was fairly to very bothersome in 4027 (80%) but untreated in 3312 (65%), of whom 2278 (69%) wanted treatment. Most of those wanting treatment would have welcomed discussion with their physician (1861 [82%] of 2278), and most wanted their physician to broach the subject (1292 [69%] of 1861).

CONCLUSIONS

Our study results have shown that patients with diabetes and/or hypertension have a high prevalence of bothersome untreated ED and want their general practitioner to initiate a discussion and provide treatment.

Are men with erectile dysfunction more likely to have hypertension than men without erectile dysfunction? A naturalistic national cohort study

PURPOSE

: We examined whether men with erectile dysfunction (ED) are more likely to have hypertension than men without ED in a managed care setting.

MATERIALS AND METHODS

: We used a naturalistic cohort design to compare hypertension prevalence rates in 285,436 men with ED to that in 1,584,230 men without ED from 1995 through 2001. We also used a logistic regression model to isolate the effect of ED on the likelihood of hypertension after controlling for subject age, census regions and 9 concurrent diseases. The ED and the nonED cohort came from a nationally representative, managed care claims database that covers 51 health plans and 28 million members in the United States. Finally, the prevalence rate difference between members with and without ED, and the OR of having hypertension were calculated.

RESULTS

: The hypertension prevalence rate was 41.2% in men with ED and 19.2% in men without ED. After controlling for subject age, census region and 9 concurrent diseases the OR was 1.383 (p <0.0001), which implies that the odds for men with ED to have hypertension were 38.3% higher than the odds for men without ED.

CONCLUSIONS

: Men with ED were more likely to have hypertension than men without ED. This evidence supports the hypothesis that ED shares common risk factors with hypertension. It also suggests that men with ED and clinicians could use ED as an alerting signal to detect and treat undiagnosed hypertension earlier.

Ultrastructural comparison of penile cavernous tissue between hypertensive and normotensive rats

Our aim was to compare the ultrastructure of penile cavernous tissue in the spontaneous hypertensive rat (SHR) and normotensive rat, and study the relation of blood pressure with erectile function. After injection of apomorphine (APO), penile erectile frequency in 16-week-old SHR (group A) and Wistar-Kyoto rat (WKY) (group B) was observed and noted. The ultrastructure of the penile cavernous tissue was studied by scanning electron microscope and transmission electron microscope. The mean blood pressures were significantly higher in group A than in group B (P=0; 171.20+/-10.94 and 117.60+/-12.38, n=5, for group A and group B, respectively). After treatment of the two groups with APO, the erectile frequency in group A was significantly less than in group B (P=0.007; 0.40+/-0.55 and 2.40+/-1.14, n=5, for group A and group B, respectively). Significant ultrastructural pathological changes were observed in the tunica albuginea and penile cavernous tissue of SHR. The elastic fibers were decreased and the collagen fibers of the sinusoid were increased in group A. The tunica albuginea thickness (mean+/-s.d.) was 100.20+/-7.22 microm and 126.00+/-7.65 microm in group A and group B, respectively. The tunica albuginea of group A was significantly thinner than that in B (P=0.001). Some endothelial cells and smooth muscle cells exhibited damaged mitochondria, and endoplasmic reticulums and Schwann cells were degenerated in group A. Although the function of penile erection might be affected by a secondary effect related to endothelial dysfunction of hypertension, these ultrastructural pathological changes of the penile cavernous tissue might also be one of the important mechanisms of erectile dysfunction caused by hypertension.

Long‐Term Effect of Inhibition of the Angiotensin‐Converting Enzyme (ACE) on Cavernosal Perfusion in Men with Atherosclerotic Erectile Dysfunction: A Pilot Study

INTRODUCTION

Impaired perfusion of the corpora cavernosa is considered an important causal factor of erectile dysfunction (ED) in the aging male with atherosclerosis. Aim. On the basis of this notion, we hypothesized that inhibition of angiotensin-converting enzyme (ACE) may have a structural beneficial effect on cavernosal perfusion and subsequently on erectile function in men with impaired cavernosal perfusion.

METHODS

A total of 59 men with atherosclerotic ED (mean age, 60.0 +/- 6.8 years) and impaired cavernosal perfusion, as demonstrated with penile-pharmaco duplex ultrasonography, were randomized between an ACE inhibitor and placebo treatment arm. The minimum period of intervention was 26 weeks (26-46 weeks). The goal of the study was to demonstrate an improvement of (i) cavernosal arterial perfusion demonstrated by a decrease of blood flow velocity waveform; and (ii) erectile function in the erection domain of the International Index of Erectile Function.

RESULTS

Cavernosal perfusion improved significantly (paired samples t-test, P < 0.05) in both study arms, but the improvement did not differ significantly (anova, P > 0.05) between both arms. The number of sexually active men increased, and the severity of ED decreased in both groups.

CONCLUSION

Although a persisting improvement of cavernosal perfusion by at least a 6 month-administration of an ACE inhibitor in men with advanced atherosclerotic ED could not be demonstrated in this pilot study, the beneficial effect on cavernosal perfusion, sexual activity, and erectile function in all participants of this study is remarkable. This pilot study warrants a follow-up study in sexually more active men with ED and less advanced atherosclerosis to show that ACE inhibition may result in persisting improvement of cavernosal perfusion.

Pathophysiology of Erectile Dysfunction

INTRODUCTION

Multiple regulatory systems are involved in normal erectile function. Disruption of psychological, neurological, hormonal, vascular, and cavernosal factors, individually, or in combination, can induced erectile dysfunction (ED). The contribution of neurogenic, vascular, and cavernosal factors was thoroughly reviewed by our committee, while psychological and hormonal factors contributing to ED were evaluated by other committees.

AIM

To provide state of the art knowledge on the physiology of ED.

METHODS

An international consultation in collaboration with the major urology and sexual medicine associations assembled over 200 multidisciplinary experts from 60 countries into 17 committees. Committee members established specific objectives and scopes for various male and female sexual medicine topics. The recommendations concerning state-of-the-art knowledge in the respective sexual medicine topic represent the opinion of experts from five different continents developed in a process over a 2-year period. Concerning the pathophysiology of ED committee, there were seven experts from five different countries.

MAIN OUTCOME MEASURE

Expert opinion was based on the grading of evidence-based medical literature, widespread internal committee discussion, public presentation, and debate.

RESULTS

The epidemiology and classification of neurogenic ED was reviewed. The evidence for the association between vascular ED and atherosclerosis/hypercholesterolemia, hypertension and diabetes was evaluated. In addition, the pathophysiological mechanisms implicated in vascular ED were defined, including: arterial remodeling, increased vasoconstriction, impaired neurogenic vasodilatation, and impaired endothelium-dependent vasodilatation. The possible mechanisms underlying the association between chronic renal failure and ED were also evaluated as well as the evidence supporting the association of ED with various classes of medications.

CONCLUSIONS

A better understanding of how diseases interfere with the physiological mechanisms that regulate penile erection has been achieved over the last few years, which helps establish a strategy for the prevention and treatment of ED.

Persistent Lowering of Pressure by Transplanting Kidneys From Adult Spontaneously Hypertensive Rats Treated With Brief Antihypertensive Therapy

Kidney function is critical in determining the level of arterial pressure and in the pathogenesis of hypertension. Important evidence comes from studies in which the level of blood pressure is dictated by the donor when kidneys are transplanted between genetically hypertensive and normotensive rats. We have hypothesized that pharmacotherapy modifies specific properties of the kidney, particularly the vasculature, such that after kidney transplantation, there are persistent changes in the level of arterial pressure. Consistent with previous studies, a 2-week aggressive treatment of adult (15 weeks) spontaneously hypertensive rats with an angiotensin-converting enzyme inhibitor (enalapril) combined with a low-salt diet induced a persistent change in the kidney and a decrease in arterial pressure (18%). These persistent changes in arterial pressure could be completely transferred to untreated adult spontaneously hypertensive rats by kidney transplantation (ie, pressure in untreated rats was decreased after transplantation of a kidney donated from a previously treated rat). Further, the importance of kidney-specific changes was demonstrated by finding that the treatment-induced lowering of arterial pressure was completely reversed by transferring an untreated kidney into a previously treated rat. The specific treatment-induced changes to the kidney included a decrease in structurally based renal vascular resistance that was similar to the persistent lowering of arterial pressure. These data provide evidence for a link between the treatment-induced changes in kidney vascular structure and the persistent lowering of arterial pressure. The findings also suggest that a key pharmacotherapeutic target in hypertension should be kidney-specific changes, such as renal vascular structure.

Candesartan cilexetil protects cavernous tissue in spontaneously hypertensive rats

In previous experiments, our group demonstrated morphological changes in erectile tissue from male spontaneously hypertensive rats (SHR). The present study was performed to determine whether an angiotensin II receptor blocker could protect cavernous tissue (CT) from these structural alterations in SHR. Male SHR and Wistar-Kyoto (WKY) rats were studied during 4 months. Rats were divided into three groups: SHR (n=10), SHR with candesartan cilexetil (n=10) and WKY rats (n=10). Candesartan cilexetil 7.5 mg/kg/day was administered orally throughout the study. CT was processed for pathology studies. The amount of (1) cavernous smooth muscle (CSM), (2) vascular smooth muscle (VSM), (3) collagen type III, and the rat endothelial cell antibody (RECA-1)/tunica media ratio in cavernous arteries were evaluated. SHR with candesartan cilexetil showed a lower blood pressure, a lower percentage of CSM, smaller VSM area, with a higher RECA-1/media ratio, and a lower percentage of collagen type III, when compared to untreated SHR. In addition, SHR showed a positive correlation between systolic blood pressure (SBP) and CSM amount (r=0.91; P<0.01), and SBP and the percentage of collagen type III (r=0.88; P<0.01); these correlations were not observed either in SHR treated with candesartan cilexetil or in WKY rats. We conclude that candesartan cilexetil provides a significant protective role against morphologic changes in vessels as well as in cavernous spaces of the erectile tissue, caused by high blood pressure, in SHR.

Time course of vascular structural changes during and after short-term antihypertensive treatment

The present study characterized the persistent changes (ie, off-treatment) resulting from short-term antihypertensive treatments on mean arterial pressure (MAP) and structurally based vascular resistance. Rats were treated for 14 days with enalapril (30 mg x kg(-1) x d(-1)) with regular (ENAL, 0.4%) or low salt (ELS, 0.04%) diets, or a triple therapy (Triple: hydralazine 45 mg x kg(-1) x d(-1), hydrochlorothiazide 100 mg/L, and nifedipine 200 mg/d). MAP was continuously recorded via radiotelemetry. Structurally based hindlimb vascular resistance properties (resistance at maximum dilation [Max Dil]; resistance at maximum constriction [Max Con]) were assessed after 14-day enalapril treatment and 2 to 3 weeks after all drugs were withdrawn. Aortic urokinase plasminogen activator (uPA) activity was measured by zymography after 14 days of ELS. All treatments induced a significant, persistent decrease in the off-treatment MAP (ENAL downward arrow 12+/-4.6%, ELS downward arrow 16+/-2.6%, Triple downward arrow 5+/-4.17%). During treatment (14 days) the enalapril group had significant changes in the index of medial bulk (Max Con downward arrow 15+/-2.6%), but only minimal changes in lumen properties (Max Dil downward arrow 3+/-6.5%, NS). After stopping therapy, vascular properties at Max Dil were significantly decreased only in the 2 enalapril groups (ENAL downward arrow 15+/-7.9%, P<0.05; ELS downward arrow 9+/-6.0%, P<0.05; Triple downward arrow 2+/-9.8%, NS), whereas Max Con was significantly decreased in all groups (ENAL downward arrow 12+/-8.0%, ELS downward arrow 16+/-6.1%, Triple downward arrow 7+/-5.4%). At 14 days of ELS treatment, there was increased aortic uPA activity (1.6-fold). The findings reveal that various short-term antihypertensive treatments can produce persistent long-term changes in MAP and vascular structure. Further, the magnitude of the depressor response may be as important in inducing persistent changes as is the removal of angiotensin II.

Persistent lowering of arterial pressure after continuous and intermittent therapy

OBJECTIVE

The present study investigates the impact of antihypertensive treatment on persistent reduction of arterial pressure after cessation of drug treatment.

DESIGN AND METHODS

Specifically, adult spontaneously hypertensive rats (SHR) were treated for 6 weeks with inhibitors of the renin-angiotensin system (RAS), or combination therapy (hydralazine, nifedipine, hydrochlorothiazide) and following a 14-week 'drug holiday', were re-treated for 4 weeks. Mean arterial pressure (MAP) was continuously monitored via radiotelemetry.

RESULTS

Comparison in the first off-treatment period revealed that RAS inhibitor drugs produced a 16-18% persistent lowering of arterial pressure, whereas the triple therapy induced a 10% lowering of MAP relative to untreated SHR. The drug re-challenge induced a further 9% reduction in the 'off'-treatment level of MAP such that in all treatment groups MAP was reduced by more than 30 mmHg compared with controls.

CONCLUSIONS

This study provides new evidence that combination therapy, not directly targeting the RAS, can be efficacious in persistently reducing MAP off-treatment. Furthermore, we demonstrated that the 6-week treatment with RAS inhibitors induced equivalent persistent changes as a 10-week treatment. That is, the additional 4 weeks of continuous therapy was ineffective in further altering the off-treatment MAP. In contrast, with the intermittent treatment protocol (the 14-week 'drug holiday') a further effect on persistent lowering of MAP was regained. These findings suggest continuous long-term treatment with antihypertensive drugs may not be the most effective means of reversing underlying circulatory abnormalities and that the introduction of a drug holiday may be beneficial.

Erectile dysfunction in spontaneously hypertensive rats: pathophysiological mechanisms

Hypertensive men have a higher prevalence of erectile dysfunction (ED) than the general population. Experimental evidence of ED in hypertensive animals is scarce. This study evaluates the erectile function of spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto rats (WKY) in vivo by the increase in intracavernosal pressure after electrical stimulation of the cavernous nerve (CN) and by isometric tension studies on corporal strips. Frequency-dependent erectile responses to CN stimulations were reduced in SHR. Phenylephrine induced lower corporal contractions in SHR although pD2 values were similar to WKY. Endothelium-dependent relaxations to ACh were impaired significantly in SHR, and indomethacin improved these relaxations in both WKY and SHR, the latter thus reaching values similar to WKY. Corporal relaxations to sodium nitroprusside were enhanced in SHR. Thus a dysfunctional alpha-adrenergic contraction of the corporal smooth muscle, an increased cyclooxygenase-dependent constrictor tone, and/or a defect in endothelium-dependent reactivity are associated with the altered erectile mechanisms in SHR. Drugs targeting endothelial dysfunction may delay the occurrence of ED as a complication of hypertension.

Captopril treatment reverses erectile dysfunction in male stroke prone spontaneously hypertensive rats

The involvement of antihypertensive therapy in the pathology of hypertension associated male erectile dysfunction is unclear. Stroke prone spontaneously hypertensive rats (SHRSP) were treated chronically with the angiotensin converting enzyme (ACE) inhibitor captopril or placebo, normotensive rats served as controls. Mean arterial and intracavernosal pressure were measured during the induction of erection by autonomic ganglion stimulation. SHRSP-placebo treated rats were hypertensive and had a blunted erectile response. Captopril treatment returned both the blood pressure and erectile response to control levels. Therefore, ACE inhibitor therapy may not be responsible for the erectile dysfunction observed in treated hypertensive subjects.

[Aging and urology: is impotence the first symptom of aging?]

The clinical expression of ageing involves several organs with variable degrees of precociousness or intensity based on the apparatus or system. An early event in the ageing process may be the occurrence of asymptomatic, and difficult to recognise, periurethral hyperplastic nodules. On the contrary, such an obvious symptom and clinical entity as erectile dysfunction may become a highly relevant herald of ageing. And this will be more so if it appears in coincidence with widespread cardiovascular disease, specially if manifest through hypertension and ischaemic heart disease. The action of the urologist faced with a patient who asks for help for his erectile dysfunction cannot be limited to the evaluation of a simple organ disease.

Interactions between drugs for erectile dysfunction and drugs for cardiovascular disease

The association of erectile dysfunction (ED) and cardiovascular disease is well-documented in the literature and both conditions share risk factors. Therefore, it is difficult to distinguish the effect of underlying disease and adverse effects of the drugs and/or interactions between ED drugs and drugs implemented for cardiovascular disease. The known interactions of systemic administered drugs for ED with drugs for cardiovascular disease are mainly pharmacodynamic. Thus, nitrates enhance the production of cyclic GMP and combined with phosphodiesterase type-5 inhibitors this can lead to severe hypotension. The same is the case for the treatment with phentolamine in patients treated with beta-adrenoceptor antagonists. Due to increased partial thromboplastin time, the risk of bleeding is enhanced for intracavernous alprostadil injection in heparin-treated patients. Pharmacokinetic interactions of clinical importance have been described for ED drugs with other therapeutic groups such as sildenafil with the antifungal drug, ketoconazole, and apomorphine with the antiparkinson drug, entacapon. Although sildenafil and antihypertensive dihydropyridines like amlodipine are metabolized by the same cytochrome P450 enzyme, CYP3A4 in the liver, the combination of these drugs does not exhibit a synergistic blood pressure lowering action. Unfortunately documentation concerning drug interactions is often poor and occasional.