Vasculogenic erectile dysfunction: beyond the haemodynamic changes

Comparison of preoperative penile elastographic ultrasound findings and pathological tissue results of patients implemented with penile prosthesis

OBJECTIVE

Histopathological analysis of the relationship between penile elastography and erectile dysfunction.

MATERIAL AND METHOD

12 patients who applied to our clinic for erectile dysfunction in the last 1 year and accepted this study were included. Preoperative two-dimensional shear wave elastography imaging was performed in 12 patients and recorded in the Pascal (kPa) unit. Approximately 0.5 × 0.5 × 0.5 cm tissue samples were taken from the right and left cavernous tissue during penile prosthesis implantation operation. Tissue samples were sent to the pathology department. The percentage of the area covered by muscle fibers and elastic fibers in the corpus cavernosum was noted semi-quantitatively (ratio of muscle fibers and cavernous body elastic fiber score). All data obtained were compared with each other.

RESULTS

Cavernous body elastic fiber score data(Grouped Score 1, 2 and 3) and percentage of cavernous body muscle fibers data (Grouped %10, %20, %30… %100) were compared with Shear wave elastography data (kPa). The results were not statistically significant according to the Kruskal Wallis Test. Cavernous body elastic fiber score and the percentage of cavernous body muscle fibers were also compared, it was not statistically significant according to the Kruskal Wallis test and Spearman's correlation test.

CONCLUSIONS

Penile shear wave elastography can be used clinically to quantitatively assess the amount of smooth muscle cells and elastic fibers in the penis, but it deserves to be studied with a larger number of patients and a more specific interpretation of the pathology preparation.

Blood Pressure, Sexual Activity, and Erectile Function in Hypertensive Men: Baseline Findings from the Systolic Blood Pressure Intervention Trial (SPRINT)

INTRODUCTION

Erectile function, an important aspect of quality of life, is gaining increased research and clinical attention in older men with hypertension.

AIM

To assess the cross-sectional association between blood pressure measures (systolic blood pressure [SBP]; diastolic blood pressure [DBP]; and pulse pressure [PP]) and (i) sexual activity and (ii) erectile function in hypertensive men.

METHODS

We performed analyses of 1,255 male participants in a larger randomized clinical trial of 9,361 men and women with hypertension aged ≥50 years.

MAIN OUTCOME MEASURES

The main outcome measures were self-reported sexual activity (yes/no) and erectile function using the 5-item International Index of Erectile Function (IIEF-5).

RESULTS

857 participants (68.3%) reported being sexually active during the previous 4 weeks. The mean (SD) IIEF-5 score for sexually active participants was 18.0 (5.8), and 59.9% of the sample reported an IIEF-5 score <21, suggesting erectile dysfunction (ED). In adjusted logistic regression models, neither SBP (adjusted odds ratio = 0.998; P = .707) nor DBP (adjusted odds ratio = 1.001; P = .929) was significantly associated with sexual activity. In multivariable linear regression analyses in sexually active participants, lower SBP (β = -0.04; P = .025) and higher DBP (β = 0.05; P = .029) were associated with better erectile function. In additional multivariable analyses, lower PP pressure was associated with better erectile function (β = -0.04; P = .02).

CLINICAL IMPLICATIONS

Blood pressure is an important consideration in the assessment of erectile function in men with hypertension.

STRENGTHS & LIMITATIONS

Assessments of blood pressure and clinical and psychosocial variables were performed using rigorous methods in this multi-ethnic and geographically diverse sample. However, these cross-sectional analyses did not include assessment of androgen or testosterone levels.

CONCLUSIONS

Erectile dysfunction was highly prevalent in this sample of men with hypertension, and SBP, DBP, and PP were associated with erectile function in this sample. Foy CG, Newman JC, Berlowitz DR, et al. Blood Pressure, Sexual Activity, and Erectile Function in Hypertensive Men: Baseline Findings from the Systolic Blood Pressure Intervention Trial (SPRINT). J Sex Med 2019;16:235-247.

An experimental study: evaluating the tissue structure of penis with 2D-ShearWave™ Elastography

The aim of this study was to investigate the feasibility of two-dimensional-ShearWave™ Elastography (2D-SWE) on evaluating the change of tissue structure of penis. Twenty healthy male Sprague Dawley rats were divided into penis-developed group (PDG, 52 weeks) and penis-underdeveloped group (PUDG, 5 weeks). The ultrafast ultrasound device-Aixplorer® (SuperSonic Imagine) was used for 2D-SWE imaging of the penis, the measurement index was shear wave stiffness (SWS, kPa). All rat penises were cut off immediately after ultrasonic examination. After paraffin embedding, slicing and hematoxylin-eosin staining, the tissue structure of the penis was observed under light microscope. SWS of all rat penises were measured successfully. The results showed that SWS of PDG was significantly lower than PUDG (P=0.008). At the same time, the pathological results found that there were significant differences in the tissue structures (sinusoids, smooth muscle cells and fibrocytes) of the penises between the two groups. These results suggest that there are significant differences in SWS between different tissue structures of penis. 2D-SWE is expected to be used on the etiological diagnosis of erectile dysfunction by serving as a new noninvasive method of evaluating the change of tissue structure of penis.

Melatonin Improves Erectile Function in Rats With Chronic Lower Body Ischemia

INTRODUCTION

Arterial occlusive disease is the leading cause of erectile dysfunction (ED). Using an established rat model we wanted to characterize the changes caused by atherosclerosis-induced chronic ischemia on penile structures and erectile function.

AIM

To investigate the effect of melatonin on these parameters.

METHODS

Adult male Sprague-Dawley rats were divided into control, arterial injury (AI) and AI with melatonin treatment groups. AI and AI-melatonin groups underwent endothelial injury of the iliac arteries and received a 2% cholesterol diet following AI surgery for 8 weeks. AI-melatonin group rats received melatonin (20 mg/kg/day) orally for 8 weeks after AI. The control group received a regular diet. After 8 weeks, erectile function was tested. Corpus cavernosum (CC) tissues were processed for pharmacological and immunohistochemical studies, histological examination, and Western blotting.

MAIN OUTCOME MEASURES

Apomorphine test was performed to evaluate erectile function. Organ bath study was performed to measure the CC-contraction induced by KCl and phenylephrine, and relaxation induced by electrical field stimulation (EFS) and sodium nitroprusside (SNP).

RESULTS

The number of erectile responses was significantly lower in the AI group (2.5 ± 0.5/hour) than in the control (5.0 ± 0.7/hour) and in the melatonin-treated groups (5.0 ± 0.3/hour). The responses to phenylephrine were lower in the AI-groups than in the controls, but there were no differences between control and AI-melatonin groups. SNP-induced relaxation in the AI-melatonin group was higher than in the AI, but lower than in control group. The EFS-elicited relaxation responses in the AI group were significantly lower than in the control and AI-melatonin groups. Compared to controls, CC tissues from the AI group showed significantly higher collagen content, and lower protein expression of eNOS and nNOS, and increased expression of iNOS. These changes were reduced or prevented by melatonin treatment.

CONCLUSION

Treatment with melatonin reduced/prevented functional and morphological changes induced by chronic ischemia on penile structure and function.

The role of interventional radiology in the diagnosis and management of male impotence

Erectile dysfunction (ED) is defined as the persistent inability to reach or maintain penile rigidity enough for sexual satisfaction. Nearly 30% of the men between ages 40 and 70 years are affected by ED. A variety of pathologies, including neurological, psychological, or endocrine disorders and drug side effects, may incite ED. A commonly identified cause of ED is vascular disease. Initial diagnostic workup includes a detailed physical examination and laboratory tests. Whilst duplex ultrasound is considered the first-line diagnostic modality, intra-arterial digital subtraction angiography is still considered the "gold standard" for the diagnosis of arteriogenic impotence. Percutaneous endovascular treatment may be offered in patients with vasculogenic ED that has failed to respond to oral medical therapy as an alternative to penile prosthesis or open surgical repair. In arteriogenic ED balloon angioplasty of the aorto-iliac axis, and in veno-occlusive ED, percutaneous venous ablation using various embolization materials has been reported to be safe and to improve sexual performance. Recently, the ZEN study investigated the safety and feasibility of drug-eluting stents for the treatment of arteriogenic ED attributed to internal pudendal artery stenosis with promising preliminary results. This manuscript highlights the role of interventional radiology in the diagnosis and minimally invasive treatment of male impotence.

A study of the early changes of the level of calcitonin gene-related Peptide and histopathology of penises of rats with experimentally induced type I diabetes mellitus by streptozocin

Introduction

Diabetes mellitus (DM) is a multiorgan disease that leads to neurovascular complications that disturb the normal erectile function.

Aim

The aim of the current work was to study the early changes occurring in the level of calcitonin gene-related peptide (CGRP) and histopathological changes in penile tissues of uncontrolled diabetic rats.

Materials and Methods

This study was carried on 50 adult male Sprague-Dawley rats divided into two main groups: group I (control, n = 10) and group II (diabetic, n = 40). Type I DM was induced by a single intraperitoneal injection of streptozotocin (60 mg/kg). The tissue level of CGRP and histopathological examination of rat penises were assessed at 2, 4, 6, and 8 weeks after induction of DM.

Results

CGRP was higher in the diabetic group at 4, 6, and 8 weeks than in the control group. However, endothelial changes and decreased smooth muscles mass started only 2 weeks after induction of DM.

Conclusion

Deterioration of histopathological features of the uncontrolled diabetic rats corporeal tissues is time dependent. Furthermore, vascular changes seem to precede the neurological changes. El-Kamshoushi AAM, Abdallah WI, Helal SF, El Azhary NM, and Hassan EM. A study of the early changes of the level of calcitonin gene-related peptide and histopathology of penises of rats with experimentally induced type I diabetes mellitus by streptozocin. Sex Med 2013;1:21–29.

Therapeutic angiogenesis as a potential future treatment strategy for erectile dysfunction

The cavernous endothelium plays a crucial role in regulating the tone of the underlying smooth muscle and physiologic penile erection. Recently, the link between erectile dysfunction (ED) and cardiovascular disease was unveiled, and the main etiology of ED was found to be vasculogenic. Although oral phosphodiesterase-5 inhibitors are generally effective for men with ED, such therapies do not cure underlying vasculopathy in the corpus cavernosum tissue. This review addresses current preclinical protein, gene, and cell or stem cell therapies for enhancing cavernous endothelial regeneration and restoring erectile function.

Does regular consumption of green tea influence expression of vascular endothelial growth factor and its receptor in aged rat erectile tissue? Possible implications for vasculogenic erectile dysfunction progression

Erectile dysfunction (ED) is a highly prevalent disease affecting millions of men worldwide with a tendency for widespread increase. ED is now considered an early manifestation of atherosclerosis and, consequently, a precursor of systemic vascular disease. Atherosclerosis and ED share potentially modifiable risk factors, as smoking or high-fat food intake, but it is unclear how regular consumption of anti-oxidant rich drinks, which exhibit recognised anti-atherosclerotic features, affects ED progression. The objective of this study was to evaluate the modulating effects of chronic consumption of catechin-rich beverages on the vascular structure of the rat corpus cavernosum, and how this could contribute to delay or prevention of the onset of ED. Male Wistar rats aged 12 months were treated with green tea (GT) or a green tea extract solution (GTE) as the only liquid source for 6 months. Consumption of GT and GTE led to decreased plasma androgen levels without any significant change in plasma lipid levels. A reduction in corpus cavernosum intracellular storage of lipids, associated with decreased expression of vascular endothelial growth factor (VEGF) and its receptor VEGFR2 in endothelial cells, was observed. Taken together, these results suggest diminished atherosclerotic progression in cavernous tissue. However, functional studies will be necessary to elucidate if catechin-rich beverages are useful compounds in the prevention of deleterious vascular events associated with ED. It was also demonstrated that regular consumption of catechins reduces atherosclerotic progression and mortality due to cardiovascular disease. The results reported here suggest diminished atherosclerotic progression in cavernous tissue in aged rats following chronic ingestion of catechin-rich beverages.

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.

High cholesterol feeding in C57/Blc6 mice alters expression within the VEGF receptor-ligand family in corporal tissue

INTRODUCTION

Angiogenesis, the growth and proliferation of blood vessels from existing vascular structures, is mediated by many cytokine growth factors and receptors, among the most important are the vascular endothelial growth factor (VEGF) family.

AIM

Decreases in VEGF receptor signaling have been linked to abnormalities in vasoreactivity in corporal tissue, but it is unknown if alterations in the VEGF ligands and/or receptors contribute to this process.

MAIN OUTCOME MEASURES

We sought to determine changes in vasoreactivity and the expression of the family of VEGF ligands and receptors in corporal tissue with cholesterol feeding in C57BL6 mice. Methods. Twenty-four mice (N = 8/group) were fed a normal diet (Group 1) or a 1.25% high cholesterol diet for 4 (Group 2) or 12 (Group 3) weeks. Isometric tension studies were performed on corporal strips and dose response curves were generated to evaluate endothelium-dependent and endothelium-independent vasoreactivities. Levels of VEGF-A, B, C, D, VEGF receptors (VEGFRs) were detected by PCR (polymerase chain reaction) and/or western blot/enzyme-linked immunosorbent assay (ELISA). Endothelial and smooth muscle cell contents were determined by immunohistochemistry.

RESULTS

At 4 weeks there was a small but significant decrease in endothelium-dependent vasoreactivity. Both mRNA and protein levels of VEGFR-1 were decreased, while VEGF-B was increased in Group 2 vs. Group 1, with no change in VEGF-A or endothelial cell content. By 12 weeks, decreases in both endothelium-dependent and endothelium-independent vasoreactivity were evident with decrease in most VEGF ligands (except VEGF-B), receptors, and receptor signaling.

CONCLUSIONS

Cholesterol feeding in C57BL6 mice results in alterations in the VEGF receptor-ligand family that may initially serve to limit the degree of vascular injury but these adaptations fail with the continuation of cholesterol feeding.

Physiological regulation of penile arteries and veins

Recent experimental evidence suggests that arterial insufficiency precedes the structural and functional changes in corpora cavernosa (CC) leading to organic erectile dysfunction (ED). The present review gives an overview of the physiological factors involved in the regulation of penile vasculature. Sympathetic nerves maintain flaccidity and tonically released noradrenaline induces vasoconstriction of both arteries and veins through alpha(1)- and alpha(2)-postsynaptic receptors and downregulates its own release and that of nitric oxide (NO) through alpha(2)-presynaptic receptors. The sympathetic cotransmitter neuropeptide Y (NPY) modulates noradrenergic vasoconstriction in penile small arteries by both enhancing and depressing noradrenaline contractions through Y(1)- and Y(2)-postsynaptic and a NO-independent atypical endothelial receptor, respectively. Activation of alpha(1)-adrenoceptors involves both Ca(2+) influx through L-type and receptor-operated Ca(2+) channels (ROC) and Ca(2+) sensitization mechanisms mediated by protein kinase C (PKC), tyrosine kinases (TKs) and Rho kinase (RhoK). In addition, RhoK can regulate Ca(2+) entry in penile arteries upon receptor stimulation. Vasodilatation of penile arteries and large veins during erection is mediated by neurally released NO. The subsequent increased arterial inflow to the cavernosal sinoids and shear stress on the endothelium lining penile arteries activates endothelial NO production through Akt phosphorylation of endothelial NO synthase (eNOS). NO stimulates guanylate cyclase and increased cyclic guanin 3'-monophosphate (cGMP) levels in turn activate protein kinase G (PKG), which enhances K(+) efflux through Ca(2+)-activated (K(Ca)) and voltage-dependent Ca(2+) (K(v)) channels in penile arteries and veins, respectively. PKG-mediated decrease in Ca(2+) sensitivity and its regulation by RhoK remains to be clarified in penile vasculature. Phosphodiesterase type 5 (PDE5) inhibitors are potent vasodilators of penile resistance arteries and increase the content and effects of basally released endothelial NO. Endothelium-dependent relaxations of penile small arteries also include an endothelium-derived hyperpolarizing factor (EDHF)-type response, which is impaired in diabetes and hypertension-associated ED. Locally produced contractile and relaxant prostanoids regulate penile venous and arterial tone, respectively. The latter activates prostaglandin I (IP) and prostaglandin E (EP) receptors coupled to adenylate cyclase and to the increase of cyclic adenosine monophosphate (cAMP) levels, which in turn stimulates K(+) efflux through ATP-sensitive K(+) (K(ATP)) channels. There is a crosstalk between the cGMP and cAMP signaling pathways in penile small arteries. Relevant issues such as the mechanisms underlying the excitation-secretion coupling of the endothelial cells, as well as those involved in cell proliferation and vascular remodeling of the penile vasculature remain to be elucidated. In addition, only few studies have investigated the changes in structure and function of penile arteries in cardiovascular risk situations leading to ED.