Erectile Hydraulics: Maximizing Inflow While Minimizing Outflow

Role of mechanotransduction mediated by YAP/TAZ in the treatment of neurogenic erectile dysfunction with low-intensity pulsed ultrasound

BACKGROUND

Erectile dysfunction (ED) and weakness of the penis are processes related to hemodynamic alteration. Low-intensity pulsed ultrasound (LIPUS), as a new mechanical modality for the treatment of ED, deserves to be explored in depth for the biomechanical mechanisms it exerts.

OBJECTIVE

The aim of this study was to explore the role of YAP/TAZ-mediated mechanotransduction in mechanical therapy for the treatment of neurogenic erectile dysfunction (NED).

MATERIALS AND METHODS

Forty-two male SD rats (12 w old) were randomly divided into sham-operated (n = 14), bilateral cavernous nerve injury (BCNI, n = 14), and LIPUS-treated (n = 14) groups. Intracavernosal pressure/mean arterial pressure (ICP/MAP) was measured 14 and 28 days after treatment. Penile tissue specimens were collected for pathological examination, and the changes in YAP, TAZ, connective tissue growth factor (CTGF), CYR61, LATS1, and p38 mitogen-activated protein kinase expression levels were assessed by Western blot, real-time quantitative polymerase chain reaction (RT-qPCR) and immunological staining.

RESULTS

Compared with BCNI, LIPUS significantly improved ICP/MAP levels and enhanced histopathological changes. The penile expression levels of YAP, TAZ, CTGF, and CYR61 were significantly downregulated in the BCNI group (p < 0.01), and LIPUS upregulated the expression levels of these proteins (p < 0.05). The expression levels of p-LATS1 and LATS1 were not significantly different among the groups (p > 0.05). Interestingly, the expression level of p-p38/p38 significantly increased in BCNI rats (p < 0.05), which was reversed by LIPUS treatment (p < 0.05). However, the p38 inhibitor SB203580 did not change the expression of YAP/TAZ in rat primary smooth muscle cells or mouse MOVAS cells (p > 0.05).

DISCUSSION AND CONCLUSION

LIPUS can effectively improve penile erectile function in NED rats. The underlying mechanism may be related to the regulation of YAP/TAZ-mediated mechanotransduction. However, the upstream regulatory signal may differ from the classical Hippo pathway.

Mechanism associated with changes in male reproductive functions during ageing process

Ageing is a natural process with physiological changes in different body parts and has been associated with decreased reproductive capacity. Factors such as imbalance in the antioxidant defence system, vascular diseases, diabetes mellitus, accessory reproductive glands infection, obesity as well as buildup of toxic substances play a role in age-related male reproductive malfunction. Age is inversely proportional to volume of semen, sperm count, sperm progressive motility, sperm viability, normal sperm morphology. The observed negative correlation between ageing and semen indices contributes to male infertility and reproductive decline. Normal levels of ROS, plays crucial role in facilitating sperm function, such as capacitation, hyper-activation, acrosome reaction as well as sperm-oocyte fusion; however, a substantial elevation in the endogenous level of ROS, especially in reproductive tissues, usually instigates destruction of sperm cells and heightened male infertility. Contrarily, antioxidants, such as vitamins C and E, beta-carotene, and micronutrients like zinc and folate, have been found by researchers to facilitate normal semen quality and male reproductive function. Furthermore, the role of hormonal imbalance as a result of the compromised hypothalamic-pituitary-gonadal axis, Sertoli and Leydig cells disorder, and nitric oxide-medicated erectile dysfunction during ageing cannot be undermined.

Comparative Transcriptome Analyses of Geriatric Rats Associate Age-Related Erectile Dysfunction With a lncRNA-miRNA-mRNA Regulatory Network

BACKGROUND

The key regulatory roles of long non-coding RNAs (lncRNAs) in age-related erectile dysfunction (A-ED) are unknown.

AIM

This study aimed to identify putative lncRNAs that regulate age-related erectile dysfunction via transcriptome analyses, and to predict their specific regulatory routes via bioinformatics methods.

METHODS

22 geriatric male SD rats were divided into age-related erectile dysfunction (A-ED) and negative control (NC) groups after evaluations of intracavernous pressure (ICP). By comparative analysis of transcriptomes of cavernosal tissues from both groups, we identified differentially expressed lncRNAs, miRNAs, and mRNAs. Seven differentially expressed lncRNAs were selected and further verified by quantitative real-time polymerase chain reactions (RT-qPCR). The construction of the lncRNA-miRNA-mRNA network, the Gene Ontology (GO) term enrichment, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed in Cytoscape.

RESULTS

From comparative transcriptome analyses of A-ED and NC groups, 69, 29, and 364 differentially expressed lncRNAs, miRNAs, and mRNAs were identified respectively. Differentially expressed lncRNAs were culled to seven, which were all verified by qPCR. Three of these lncRNAs (ENSRNOT00000090050, ENSRNOT00000076482, and ENSRNOT00000029245) were used to build regulatory networks, of which only ENSRNOT00000029245 was successful. Moreover, GO and KEGG analyses demonstrated that these lncRNAs possibly regulated muscle myosin complex, muscle cell cellular homeostasis, and ultimately erectile function in rats through PI3K-Akt, fluid shear stress, and atherosclerosis pathways.

CONCLUSION

Our study identified differentially expressed lncRNAs, miRNAs, and mRNAs through comparisons of transcriptomes of geriatric rats. An identified lncRNA verified by qPCR, was used to construct a lncRNA-miRNA-mRNA regulatory network. LncRNA ENSRNOT00000029245 possibly regulated downstream mRNAs through this regulatory network, leading to apoptosis in the cavernous tissue, fibrosis, and endothelial dysfunction, which ultimately caused ED. These findings provide seminal insights into the molecular biology of aging-related ED, which could spur the development of effective therapeutics.

Prevalence of Erectile Dysfunction and Associated Factors among Hypertensive Patients Attending Governmental Health Institutions in Gondar City, Northwest Ethiopia: A Cross-Sectional Study

Introduction

Erectile dysfunction is a common sexual problem affecting men with hypertension. It may result in withdrawal from sexual engagement, decreased work productivity, psychosocial problems including poor self-esteem and depression, and reduction in quality of life for both the affected men and their female partners.

Objective

This study was aimed to determine the prevalence of erectile dysfunction and associated factors among hypertensive patients attending governmental health institutions in Gondar city, Northwest Ethiopia.

Materials and Methods

An institutional-based cross-sectional study was conducted on 423 hypertensive men randomly selected using a systematic random sampling technique. Erectile dysfunction was assessed using the International Index of Erectile Function-5 tool. Sociodemographic, clinical, and behavioral factors were also collected using pretested interviewer-administered questionnaires. Data were entered into EpiData version 4.6 and analyzed using Stata-14. Binary logistic regression was performed to identify factors associated with erectile dysfunction. The level of significance was computed at a p value ≤ 0.05.

Results

The mean age of the study participants was 58.84 ± 13.52 years. The prevalence of erectile dysfunction among hypertensive men was 46.34% (95% CI: 41.61, 51.12). About 28% of them had a mild form of erectile dysfunction while nearly 6% had severe forms. Age above 60 years (AOR = 3.8, 95% CI: 1.62, 6.55), stage II hypertension (AOR = 3.5, 95% CI: 1.63, 5.74), hypertension duration >10 years (AOR = 2.5, 95% CI:1.12, 4.19), comorbidity (AOR = 1.7, 95% CI: 1.04, 3.15), depression (AOR = 2.35, 95% CI: 1.31, 4.21), and being physically active (AOR = 0.48, 95% CI: 0.28, 0.83) were factors significantly associated with erectile dysfunction.

Conclusion

Nearly half of the study participants had some form of erectile dysfunction, indicating the presence of a high burden of the problem. Assessment of hypertensive men for erectile dysfunction should be part of routine medical care.

Communication about physical activity to reduce vascular erectile dysfunction - A qualitative interview study among men in cardiac rehabilitation

BACKGROUND

Physical activity, a core intervention in cardiac rehabilitation, can reduce vascular erectile dysfunction (ED). ED is a common sensitive problem for men with cardiac diseases, decreasing their quality of life. Cardiac health professionals rarely provide information about ED or its relation to physical activity. Developing health professionals' communicative component of the complex intervention 'Physical Activity to reduce Vascular Erectile Dysfunction' (PAVED) is important. Understanding the receiver needs is essential in designing a complex intervention.

AIM

To elucidate men's perspectives on cardiac health professionals' communication about PAVED.

ETHICAL ISSUES

An Institutional Data Protection Agency approved the study.

METHODS

An interpretive data-driven thematic analysis was applied to individual, qualitative semi-structured interviews with 20 Danish men attending cardiac rehabilitation.

RESULTS

The men wanted health professionals' communicating about ED, as it was perceived as a major problem diminishing masculinity and tabooed by health professionals. Men wanted help for self-help, which may be possible with the aid of competent health professionals' communication about how to prevent, reduce and cope with ED - including information about PAVED. The men wanted health professionals' communication about ED in various contexts: general information in groups, sexual counselling for individuals and couples and written material.

STUDY LIMITATIONS

Recruitment was done from a Danish municipality's cardiac rehabilitation, and the transferability of the results may be limited to similar contexts.

CONCLUSION

Erectile dysfunction was experienced as a major biopsychosocial problem for the men and their partners. The men had a need for health professionals' communication about sexuality, ED and information about PAVED as well as about prevention, reduction and management of ED. The men had a need for professional communication about sexual health.

Serum lipocalin-2 and carotid artery intima-media thickness in relation to obesity in eugonadal males over forty with venogenic erectile dysfunction

Obesity is a risk factor for erectile dysfunction and atherosclerosis. Lipocalin-2 is an adipocytokine with proinflammatory properties involved in several disorders with metabolic alterations. Our aim was to study the relation of serum lipocalin-2 and carotid artery intima-media thickness (CIMT) to obesity in erectile dysfunction. Serum lipocalin-2 and CIMT were measured in 25 obese and 25 nonobese eugonadal patients over forty with venogenic erectile dysfunction and 25 healthy controls. Their relation to different patient- and disease-related parameters was studied. Results revealed lipocalin-2 to be significantly higher in obese compared with nonobese patients and with controls, and in nonobese patients compared with controls. CIMT was lower in controls compared with both obese and nonobese patients. In obese and nonobese patients, lipocalin-2 was positively correlated with disease duration, body mass index, waist circumference and end-diastolic velocity. Lipocalin-2 was negatively correlated with the short form of the international index of erectile function scores in both groups. In conclusion, the elevated lipocalin-2 in obese and to a lesser extent in nonobese patients and its association with disease severity points to its potential value as a diagnostic marker and a possible therapeutic target that could ameliorate the metabolic derangement associated with erectile dysfunction.

Aging and erectile function

The authors review and discuss numerous factors that influence erectile function and their interactions, based on the published literature. Of critical importance are vascular nitric oxide; nutrition; exercise; weight control and maintaining insulin sensitivity; early treatment of hypertension with attention to effects on erectile function; avoiding sources of oxidative stress such as obesity and smoking; reducing inflammation (e.g. from gingivitis); improving pelvic floor muscle strength; and inhibiting cyclic GMP break-down. The described interventions act on different aspects of erectile biochemistry and physiology. Therefore, combining multiple therapeutic approaches will yield maximum benefits for erectile and vascular and general health.

Standardization of penile hemodynamic evaluation through color duplex-doppler ultrasound

INTRODUCTION

The vascular evaluation of the erectile function through Color Duplex-Doppler Ultrasound (CDDU) of the penis can benefit the therapeutic decision-making process. Unfortunately, there is no standard procedure for CDDU conduction, a fact that results in high result-interpretation variability.

OBJECTIVE

The aims of this review are to promote greater standardization during CDDU of the penis and discuss the fundamental principles for its accurate conduction.

METHODS

CDDU is initially conducted with the penis in the flaccid state; the whole penis must be assessed (images at B mode) with a high-frequency linear transducer (7.5-18 MHz). Intracavernous injection of vasodilating agents (prostaglandin E1, papaverine, phentolamine) is performed to induce a rigid erection. Serial measurements at different times should be taken during the CDDU session and penile rigidity must be assessed in each evaluation.

RESULTS

It is important to monitor the erection response after the vasoactive agent (hardness scale), and scanning during the best-quality erection should be contemplated. Manual self-stimulation, audiovisual sexual stimulation (AVSS), and vasoactive agent re-dosing protocols must be taken into account to reduce the influence of psychogenic factors and to help the patient to get the hardest erection possible. Such measurements contribute to the maximal relaxation of the erectile tissue, so the hemodynamic parameters are not underestimated.

CONCLUSIONS

CDDU is a relevant specialized tool to assess patients with erectile dysfunction; therefore, this guideline will help to standardize and establish uniformity in its conduction and interpretation, taking into consideration the complexity and heterogeneity of CDDU evaluations of the penis.

Coexistence of vasculogenic erectile dysfunction and peripheral artery disease

Erectile dysfunction (ED) is the most common sexual problem experienced by men. The incidence increases with age and causes significant negative impacts on self-esteem, intimate relationships, mental health, and may be a powerful prognostic indicator for underlying vascular disease. The purpose of this clinical column is to provide an overview of the pathophysiology, evaluation, and management of vasculogenic ED in a patient with peripheral artery disease. There is very little research focused on the coexistence of these two disease conditions.

Evaluation of Age- and Radical-Prostatectomy Related Changes in Male Pelvic Floor Anatomy Based on Magnetic Resonance Imaging and 3-Dimensional Reconstruction

Purpose

Puborectalis muscles (PRM) and ischiocavernosus muscles (ICM) play important roles in urinary continence and male erectile functions. Understanding of anatomy and surgical-injury related changes to these muscles is critical to monitor changes in continence or erectile function. Anatomical description of these muscles has undergone revisions because these conclusions were derived from cadavers. Our objectives were to: (i) elucidate male pelvic muscles by in-vivo magnetic resonance imaging (MRI) and 3-dimensional (3-D) reconstruction of these images and (ii) compare PRM and ICM thickness in healthy volunteers and symptomatic patients.

Materials and Methods

Healthy young male (mean age, 25 years; n=5), older male (age, 65–70 years; n=5), and post-prostatectomy patients with erectile dysfunction and urinary incontinence (age, 65–70 years; n=5) were scanned on a 3T-magnetic resonance scanner. Images were acquired from slices above urinary bladder base to urethra entry into penis. Pelvic bone, bladder/urethra, corpus cavernosum, ICM, PRM, and prostate were segmented. 3-D models of each structure were generated and assembled into composite images, and ICM and PRM thicknesses were calculated.

Results

We successfully reconstructed 3-D male pelvic floor anatomy including ICM, PRM, bladder, urethra, bulbospongiosus, corpus cavernosa, prostate and bones from the two groups. We documented significant reduction in PRM and ICM thickness in older men.

Conclusions

This is perhaps the first 3-D reconstruction of male pelvic floor structures based on in-vivo MRI in healthy and symptomatic patients. Observed reduction in PRM and ICM thickness is possibly due to age-related atrophy.

Association between Frailty and Erectile Dysfunction among Chinese Elderly Men

Objective

This study is aimed at assessing association between frailty and erectile dysfunction among Chinese elderly men.

Methods

This community-based study was conducted with a sample of 341 Chinese elderly men (aged 60 to 83 years old) in Fuyang City (Anhui Province, China). Each of the participants completed a standard questionnaire, including demographics (age, height, weight, yearly income, educational status, comorbidity, lifestyle factors, etc.), medical and sexual history, and the Chinese version of Tilburg Frailty Indicator (TFI) and International Index of Erectile Function-5 (IIEF-5) for assessing frailty and erectile dysfunction (ED).

Results

The prevalence of ED and frailty in Chinese elderly men was 77.13% and 68.04%, respectively. Compared with the non-ED group, the ED group had increased age, spouse's age, BMI, prevalence of diabetes, and scores of TFI and lower yearly income, educational levels, and ratio of irregular intercourse (less than once per week) (all P < 0.05). Multivariate analysis indicated that age (OR: 0.860, 95% CI: 0.763-0.969), diabetes (OR: 0.330, 95% CI: 0.165-0.661), irregular intercourse (OR: 3.416, 95% CI: 1.874-6.229), and scores of TFI (OR: 0.906, 95% CI: 0.846-0.970) were regarded as independent risk factors for ED (all P < 0.05). And after adjusting for age, the TFI score had a negative significant association with the IIEF score (r = −0.134, P = 0.013).

Conclusion

This study confirmed the strong associations between ED and frailty among elderly men. Sexual health care for elderly men with ED should be assessed and taken addressed on the multidimensional assessments of frailty.

Muscles of the trunk and pelvis are responsive to testosterone administration: data from testosterone dose-response study in young healthy men

Testosterone dose-dependently increases appendicular muscle mass. However, the effects of testosterone administration on the core muscles of the trunk and the pelvis have not been evaluated. The present study evaluated the effects of testosterone administration on truncal and pelvic muscles in a dose-response trial. Participants were young healthy men aged 18-50 years participating in the 5α-Reductase (5aR) Trial. All participants received monthly injections of 7.5 mg leuprolide acetate to suppress endogenous testosterone production and weekly injections of 50, 125, 300, or 600 mg of testosterone enanthate and were randomized to receive either 2.5 mg dutasteride (5aR inhibitor) or placebo daily for 20 weeks. Muscles of the trunk and the pelvis were measured at baseline and the end of treatment using 1.5-Tesla magnetic resonance imaging. The dose effect of testosterone on changes in the psoas major muscle area was the primary outcome; secondary outcomes included changes in paraspinal, abdominal, pelvic floor, ischiocavernosus, and obturator internus muscles. The association between changes in testosterone levels and muscle area was also assessed. Testosterone dose-dependently increased areas of all truncal and pelvic muscles. The estimated change (95% confidence interval) of muscle area increase per 100 mg of testosterone enanthate dosage increase was 0.622 cm² (0.394, 0.850) for psoas; 1.789 cm² (1.317, 2.261) for paraspinal muscles, 2.530 cm² (1.627, 3.434) for total abdominal muscles, 0.455 cm² (0.233, 0.678) for obturator internus, and 0.082 cm² (0.003, 0.045) for ischiocavernosus; the increase in these volumes was significantly associated with the changes in on-treatment total and free serum testosterone concentrations. In conclusion, core muscles of the trunk and pelvis are responsive to testosterone administration. Future trials should evaluate the potential role of testosterone administration in frail men who are predisposed to falls and men with pelvic floor dysfunction.

Characterization of age-related penile microvascular hemodynamic impairment using laser speckle contrast imaging: possible role of increased fibrogenesis

Current technology for penile hemodynamic evaluations in small animals is invasive and has limitations. We evaluated a novel laser speckle contrast imaging (LSCI) technique to determine age‐related changes in penile microvascular perfusion (PMP) and tested the role of cavernosal muscle (CC) fibrosis mediated by Wnt‐TGF β1 signaling pathways in a mouse model. Ten young (2–3 months) and old (24–28 months) wild‐type C57BL6 male mice were subjected to PMP measured using a LSCI system. Penile blood flow (PBF, peak systolic velocity, PSV) was also measured using a color Doppler ultrasound for comparison. Measurements were made before and after injection of vasoactive drugs: prostaglandin E₁ (PGE₁) and acetylcholine (ACh). CC was processed for immunohistochemical studies for markers of endothelium and fibrosis. Protein levels were quantified by Western blot.PMP and PBF increased significantly from baseline after injection of vasoactive drugs. Peak PMP after PGE₁ and ACh was higher in young mice (225.0 ± 12.0 and 211.3 ± 12.1 AU) compared to old (155.9 ± 7.1 and 162.6 ± 5.1 AU, respectively). PSV after PGE₁ was higher in young than old mice (112.7 ± 8.5 vs. 78.2 ± 4.6 mm/sec). PSV after ACh was also higher in young (112.7 ± 5.6 mm/sec) than older mice (69.2 ± 7.1 mm/sec). PMP positively correlated with PSV (r = 0.867, P = 0.001). Immunostaining and Western blot showed increased protein expression of all fibrosis markers with aging. LSCI is a viable technique for evaluating penile hemodynamics. Increased cavernosal fibrosis may cause impaired penile hemodynamics and increased incidence of erectile dysfunction in older men.

Physical Activity to Improve Erectile Function: A Systematic Review of Intervention Studies

Introduction

The leading cause of erectile dysfunction (ED) is arterial dysfunction, with cardiovascular disease as the most common comorbidity. Therefore, ED is typically linked to a web of closely interrelated cardiovascular risk factors such as physical inactivity, obesity, hypertension, and metabolic syndrome. Physical activity (PA) has proved to be a protective factor against erectile problems, and it has been shown to improve erectile function for men affected by vascular ED. This systematic review estimated the levels of PA needed to decrease ED for men with physical inactivity, obesity, hypertension, metabolic syndrome, and/or manifest cardiovascular diseases.

Aim

To provide recommendations of levels of PA needed to decrease ED for men with physical inactivity, obesity, hypertension, metabolic syndrome, and/or cardiovascular diseases.

Methods

In accord with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review was performed of research articles specifically investigating PA as a possible treatment of ED. The review included research on ED from physical inactivity, obesity, hypertension, metabolic syndrome, and/or cardiovascular diseases. All available studies from 2006 through 2016 were checked for the predetermined inclusion and exclusion criteria to analyze the levels of PA needed to decrease ED.

Results

10 articles met the inclusion criteria, all suggesting various levels of PA needed to decrease ED for men with relevant risk factors for ED. The results of the review provided sufficient research evidence for conclusions regarding the levels of PA necessary to decrease ED.

Conclusion

Recommendations of PA to decrease ED should include supervised training consisting of 40 minutes of aerobic exercise of moderate to vigorous intensity 4 times per week. Overall, weekly exercise of 160 minutes for 6 months contributes to decreasing erectile problems in men with ED caused by physical inactivity, obesity, hypertension, metabolic syndrome, and/or cardiovascular diseases.

Gerbild H, Larsen CM, Graugaard C, Areskoug Josefsson K. Physical Activity to Improve Erectile Function: A Systematic Review of Intervention Studies. Sex Med 2018;6:75–89.

Effects of age on fertility and sexual function

As paternal age increases in the developed world, more attention has been given to the effects of age on male reproductive and sexual function. Although the biologic potential for reproductive continues for most of a man's life, changes in sperm production do occur. In addition, erectile function changes with age, caused by the same factors that lead to other vascular disease.

Physical activity and prevalence of erectile dysfunction in Japanese patients with type 2 diabetes mellitus: The Dogo Study

Aims/Introduction

To date, there is no evidence regarding the association between physical activity (PA) and erectile dysfunction (ED) among Japanese patients with type 2 diabetes mellitus. We investigated this issue among Japanese patients with type 2 diabetes mellitus.

Materials and Methods

Study participants were 460 male Japanese patients with type 2 diabetes mellitus. The definitions of exercise habit, walking habit and fast walking were based on a self‐administered questionnaire regarding PA behavior. Participants were classified into one of four PA levels based on the number of ‘Yes’ answers to the three questions in the questionnaire: (i) lowest; (ii) lower; (iii) moderate; and (iv) higher. Severe ED and moderate‐to‐severe ED were based on Sexual Health Inventory for Men score <8 and <12, respectively.

Results

The prevalence of moderate‐to‐severe ED, severe ED, exercise habit, walking habit, and fast walking was 64.6, 51.1, 36.3, 41.3 and 37.6%, respectively. Walking habit was independently inversely associated with moderate‐to‐severe ED and severe ED. Exercise habit was independently inversely associated with severe ED, but not moderate‐to‐severe ED. Higher PA was independently inversely associated with moderate‐to‐severe ED and severe ED (adjusted odds ratio 0.42, 95% confidence interval 0.21–0.85; and adjusted odds ratio 0.38, 95% CI: 0.19–0.73, respectively). There was a statistically significant inverse exposure–response relationship between the PA level and moderate‐to‐severe ED and severe ED (P for trend = 0.02 and 0.005), respectively.

Conclusions

PA might be inversely associated with ED in Japanese patients with type 2 diabetes mellitus.

The Wonders of Phosphodiesterase-5 Inhibitors: A Majestic History

The Nobel Prize winning discovery of nitric oxide (NO) in 1986 was the starting point for a new innovation in drug discovery. NO acting as a mediator at different physiological systems is believed to be involved in many physiological and pathological conditions through the formation of the second messenger cyclic guanosine monophosphate (cGMP). cGMP-dependent vasodilation effect of NO is important in regulating pulmonary and systemic pressures, maintaining penis erection, preventing atherosclerosis, preventing platelet aggregation, and protecting and controlling cardiac functions. The main enzyme involved in the termination of cGMP effects is phosphodiesterase enzyme 5 (PDE-5), which is overexpressed in ventricular hypertrophy and heart failure. A milestone in drug discovery was the selective inhibitors of PDE-5 that developed to be a multibillion dollar blockbuster in drug market. PDE-5 inhibitors are approved for the treatment of erectile dysfunctions (EDs), pulmonary hypertension, and benign prostatic hypertrophy. They are also under clinical trials for their cardiac protection against damage induced by ischemia or heart failure. This review article is an update about the pharmacotherapeutics of PDE-5 inhibitors and the majestic history that led to their discovery. The information reported in this review was obtained from the electronic sources of different databases such as PubMed Central, Google Scholar, and Scopus. Keywords used for search included cGMP (mechanisms and functions), EDs (drugs used), nitric oxide, and PDE-5 inhibitors (clinical applications). A total of 165 articles were studied, of which 45 articles were referred to in this review.

Lifestyle modifications and erectile dysfunction: what can be expected?

Erectile dysfunction (ED) is a common medical disorder whose prevalence is increasing worldwide. Modifiable risk factors for ED include smoking, lack of physical activity, wrong diets, overweight or obesity, metabolic syndrome, and excessive alcohol consumption. Quite interestingly, all these metabolic conditions are strongly associated with a pro-inflammatory state that results in endothelial dysfunction by decreasing the availability of nitric oxide (NO), which is the driving force of the blood genital flow. Lifestyle and nutrition have been recognized as central factors influencing both vascular NO production, testosterone levels, and erectile function. Moreover, it has also been suggested that lifestyle habits that decrease low-grade clinical inflammation may have a role in the improvement of erectile function. In clinical trials, lifestyle modifications were effective in ameliorating ED or restoring absent ED in people with obesity or metabolic syndrome. Therefore, promotion of healthful lifestyles would yield great benefits in reducing the burden of sexual dysfunction. Efforts, in order to implement educative strategies for healthy lifestyle, should be addressed.

Aging and the environment affect gamete and embryo potential: can we intervene?

Optimal maturation of the oocyte depends on its environment and determines embryo competence, because the embryonic genome is not active until the cleavage stage and new mitochondria are not produced until blastulation. Adverse environmental factors include aging, andropause, oxidative stress, obesity, smoking, alcohol, and psychologic stress, whereas androgen supplementation, a prudent diet, exercise, nutritional supplements, and psychologic interventions have beneficial effects. Mitochondrial function and energy production deteriorate with age, adversely affecting ovarian reserve, chromosome segregation, and embryo competence. In aging mice, the mitochondrial cofactor coenzyme Q10 reverses most of these changes. Early human experience has been encouraging, although only a small study using a shorter duration of intervention compared with the murine model has been carried out. Mitochondrial metabolic stress can result in an abnormal compensatory increase in mitochondrial DNA, which can be assessed in biopsied blastomeres of trophectoderm as a predictive biomarker of implantation failure. Psychologic stress may reduce oocyte competence by shifting blood flow away from the ovary as part of the classic "fight or flight" physiologic response, and methods to reduce stress or the body's reaction to stress improve pregnancy success. Enhancing oocyte competence is a key intervention that promises to reduce the number of euploid embryos failing to produce viable deliveries.

The association between physical activity and sexual dysfunction in patients with diabetes mellitus of European and South Asian origin: The Oxford Sexual Dysfunction Study

Background

The present study aims to evaluate the relationship between physical activity and sexual dysfunction amongst an ethnic South Asian population living in the United Kingdom and compare the association with that of the native Caucasian population.

Methods

Twenty-five general practitioner clinics from eight primary care trusts in the United Kingdom collaborated in the Oxford Sexual Dysfunction Study. In each practice, a sample of diabetic and non-diabetic patients of European/Europid and South Asian origin were invited for the study. Erectile dysfunction (ED) was assessed using a five-item version of the International Index of Erectile Function. Premature ejaculation (PE) was diagnosed using the premature ejaculation diagnostic tool. Libido was assessed by asking participants to grade their desire for sexual activity. Physical activity during the past week was assessed using the short version of the International Physical Activity Questionnaire (IPAQ). A binary logistic regression analysis was performed in all adults, Europids and South Asians with ‘presence of ED’ as the dichotomous dependent variable (0 = ED absent; 1 = ED present) and age, diabetes status, physical activity, ethnicity, current smoking and use of antihypertensive medications as the independent variables.

Results

Sample size was 510, and mean age was 56.9 ± 9.7 years. There were 63.9 % (n = 326) Europid males in the study population. The prevalence of ED was 64.5 % and it was significantly higher in men with diabetes than in those without diabetes (84.4 vs. 49.0 %, p < 0.001). The overall prevalence of PE was 28.8 %, (with diabetes 32.6 %, without diabetes 25.8 %; p = 0.109). Reduced libido was reported by 26.9 % of study participants (with diabetes 32.8 %, without diabetes 22.0 %; p < 0.01). The median (IQR) total physical activity of the study population was 2373 (3612) MET-min/week. In the IPAQ categorical score, 36.8 % (n = 184/434) males were ‘highly active’, and 17.8 % (n = 89/434) were ‘inactive’. In all adults, age (OR: 1.06), South Asian ethnicity (OR: 1.40), physical inactivity (OR: 1.62) and presence of diabetes (OR: 3.90) all were associated with significantly increased risk of developing ED. A similar result was observed in Europids but not in South Asians.

Conclusions

Erectile dysfunction was associated with physical inactivity, mainly in Europid males, irrespective of diabetes status. This association was not observed in South Asian males with or without diabetes.

The Circle of Lifestyle and Erectile Dysfunction

INTRODUCTION

Erectile dysfunction (ED) has been significantly associated with many chronic conditions including obesity, the metabolic syndrome, hypogonadism, diabetes mellitus, cardiovascular disease (CVD), lower urinary tract symptoms, and psychiatric/psychological disorders. ED is also a well-established predictor of CVD.

AIM

This review will focus on the association of ED with cardiovascular, metabolic, and cognitive conditions and discuss the effects of managing lifestyle factors in order to reduce the burden of ED and consequently outcomes in patients with chronic conditions.

METHODS

A literature search using Medline, PubMed (U.S. National Library of Medicine and the National Institutes of Health), and abstracts from scientific meetings was performed from 1990.

MAIN OUTCOME MEASURES

Main outcome measures were improvements in sexual function.

RESULTS

A total of 59 reviews on the topic were evaluated.

CONCLUSIONS

Targeting several lifestyle factors associated with CVD/metabolic/cognitive disorders, e.g., smoking, alcohol consumption, obesity, and physical activity, can have significant benefits, leading to an improvement in ED as well as testosterone levels and consequently CVD. Kirby M. The circle of lifestyle and erectile dysfunction. Sex Med Rev 2015;3:169-182.

A Toll-Like Receptor 1/2 Agonist Augments Contractility in Rat Corpus Cavernosum

INTRODUCTION

Activation of the innate immune Toll-like receptor 2 (TLR2) initiates inflammation and has been implicated in vascular dysfunction. Increased contraction and decreased relaxation responses in the penile vasculature lead to erectile dysfunction, a condition associated with inflammation. However, whether TLR2 activation plays a role in penile vascular function has not been established.

AIM

We hypothesized that activation of the TLR 1/2 heterodimer (TLR1/2) augments contractile and impairs relaxation responses of corpus cavernosum and that these perturbations of vascular function are mediated by low nitric oxide (NO) availability and enhanced activity of the RhoA/Rho-kinase pathway.

METHODS

Contraction and relaxation responses were measured in rat cavernosal strips using a myograph after incubation with a TLR1/2-activating ligand Pam3 CSK4 (Pam3), the TLR1/2 inhibitor CuCPT 22 (CuCPT), and inhibitors of NO synthase (LNAME) and Rho-kinase (Y27632). TLR2 protein expression was assessed by immunohistochemistry.

MAIN OUTCOME MEASURES

Cumulative concentration response curves, sensitivity (pEC50), and maximal response (Emax ) of cavernosal strips to vasodilatory and vasocontractile agonists were compared between treatments.

RESULTS

Pam3-treated cavernosal strips exhibited greater pEC50 and higher Emax to phenylephrine (PE) than control tissues. Inhibition of NO synthase increased Emax to PE in Pam3-treated cavernosal strips. Pam3 treatment reduced relaxation to Y27632 compared with control tissues. Inhibition of TLR1/2 activation with CuCPT returned the augmented contraction to PE and the decreased relaxation to Y27632 of Pam3-treated cavernosal strips to control values.

CONCLUSIONS

The TLR1/2 heterodimer mediates augmented contraction and reduced relaxation in rat cavernosal strips. Thus, TLR1/2 activation antagonizes vascular responses crucial for normal erectile function and implicates immune activation in vasculogenic erectile dysfunction. Immune signaling via TLR2 may offer novel targets for treating inflammation-mediated vascular dysfunction in the penis.

DPP-4 inhibition improves a sexual condition?

Erectile dysfunction (ED) is a condition of persistent inability to achieve or maintain an erection sufficient for satisfactory sexual intercourse. The etiology of ED is predominantly vascular, explained by nitric oxide metabolism disturbances being in the background. Nitric oxide enhancing drugs like phosphodiesterase 5 inhibitors, which delay the breakdown of nitric oxide, are widely used, but still without complete success. Restauration of endogenous nitric oxide production focused on improving endothelial dysfunction could be a more effective way of treatment, addressing also other vessels in the body and preventing more serious cardiovascular disease. Endothelial progenitor cells are bone marrow-derived cells found also in human circulation, and may under circumstances be embedded into the vascular intima leading to improvements in nitric oxide production and thus in endothelial function in many organs, including the penis. In this article we hypothesize the potential role of DPP-4 inhibitors, a novel class of antidiabetic drugs in increasing the number of circulating endothelial progenitor cells. Speculated mechanisms include several substrates for DPP-4 inhibitors: GLP-1, SDF-1α, substance P, and PACAP. As DPP-4 inhibitors show favorable safety profiles and do not cause hypoglycemia, they seem to be an attractive treatment option, at least in diabetic patients, and could become a part of vascular regenerative pharmacotherapy, ameliorating also symptoms related to erectile dysfunction. Since erectile dysfunction may precede other cardiovascular vascular events, because the penile arteries are smaller in size and therefore more susceptible to decreased nitric oxide production, treating this condition with an agent affecting positively also other blood vessels could help in preventing other cardiovascular events, including myocardial infarction and stroke. However, caution is required, because DPP-4 inhibitors are a heterogenous class of drugs, with variations regarding strength and duration of action, as well as selectivity and cardiovascular safety profile, which may affect properties other than those important in glucocontrol.