Erectile dysfunction as a cardiovascular risk factor in patients with diabetes

Cardiovascular/Stroke Risk Assessment in Patients with Erectile Dysfunction-A Role of Carotid Wall Arterial Imaging and Plaque Tissue Characterization Using Artificial Intelligence Paradigm: A Narrative Review

PURPOSE

The role of erectile dysfunction (ED) has recently shown an association with the risk of stroke and coronary heart disease (CHD) via the atherosclerotic pathway. Cardiovascular disease (CVD)/stroke risk has been widely understood with the help of carotid artery disease (CTAD), a surrogate biomarker for CHD. The proposed study emphasizes artificial intelligence-based frameworks such as machine learning (ML) and deep learning (DL) that can accurately predict the severity of CVD/stroke risk using carotid wall arterial imaging in ED patients.

METHODS

Using the PRISMA model, 231 of the best studies were selected. The proposed study mainly consists of two components: (i) the pathophysiology of ED and its link with coronary artery disease (COAD) and CHD in the ED framework and (ii) the ultrasonic-image morphological changes in the carotid arterial walls by quantifying the wall parameters and the characterization of the wall tissue by adapting the ML/DL-based methods, both for the prediction of the severity of CVD risk. The proposed study analyzes the hypothesis that ML/DL can lead to an accurate and early diagnosis of the CVD/stroke risk in ED patients. Our finding suggests that the routine ED patient practice can be amended for ML/DL-based CVD/stroke risk assessment using carotid wall arterial imaging leading to fast, reliable, and accurate CVD/stroke risk stratification.

SUMMARY

We conclude that ML and DL methods are very powerful tools for the characterization of CVD/stroke in patients with varying ED conditions. We anticipate a rapid growth of these tools for early and better CVD/stroke risk management in ED patients.

Autonomic neuropathy and urologic complications in diabetes

Diabetic autonomic neuropathy affects the entire autonomic nervous system and can lead to dysfunction of the cardiovascular, gastrointestinal, and genitourinary organ systems. Genitourinary dysfunction associated with diabetic autonomic neuropathy includes diabetic bladder dysfunction, sexual dysfunction, and recurrent urinary tract infections. Urological complications in diabetes mellitus are very common; in fact, genitourinary complications are more common than diabetic neuropathy or nephropathy. While several studies have reported on genitourinary dysfunction in individuals with diabetes, UroEDIC, an ancillary study to the Diabetes Control and Complications Trial (DCCT) and its observational follow up, the Epidemiology of Diabetes Interventions and Complications study (EDIC), comprehensively characterized the association between urologic complications and cardiovascular autonomic neuropathy. UroEDIC demonstrated significant associations between autonomic neuropathy and urologic complications in type 1 diabetes, specifically erectile dysfunction, female sexual dysfunction, and lower urinary tract symptoms. In this narrative review, we review the current literature on urological complications in diabetes.

Is the History of Erectile Dysfunction a Reliable Risk Factor for New Onset Acute Myocardial Infarction? A Systematic Review and Meta-Analysis

Acute myocardial infarction (AMI) occurs as a manifestation of coronary atherosclerotic disease. The occurrence of erectile dysfunction (ED) following AMI is well documented and this association and pathophysiology is often interrelated. Few studies have objectively assessed the diagnostic value of ED as a risk factor for AMI, in general. In this review, we aimed to better outline the diagnostic predictability of ED as a precursor for 'first/new onset' AMI. This review was performed using selective search terms, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. The Cochrane, Embase, PubMed, Scopus and Web of Science databases were searched (September 2018). Selected studies were further assessed for relevance and quality (Critical Appraisal Skills Program tool-Oxford). Four studies [573 participants; mean 143 (SD ± 76.3604) and median 141 participants] were eligible for analysis. Meta-analysis of the studies resulted in a pooled sensitivity of 51.36% (95% CI: 47.37-55.33%). For the single study which reported true negative and false positive cases, a specificity of 76.53% (95% CI: 68.57-83.00%) was calculated. The results of this systematic review and meta-analysis suggest that a history of ED should be used as a risk factor for new onset AMI.

Intracavernosal Adeno-Associated Virus-Mediated S100A1 Gene Transfer Enhances Erectile Function in Diabetic Rats by Promoting Cavernous Angiogenesis via VEGF-A/VEGFR2 Signaling

INTRODUCTION

Novel therapeutic targets for diabetes-induced erectile dysfunction (DED) are urgently needed. Previous studies have proved that S100A1, a small Ca²⁺-binding protein, is a pluripotent regulator of cardiovascular pathophysiology. Its absence is associated with endothelial dysfunction, the central event linking cardiovascular changes in diabetes. However, the role of S100A1 in DED remains unknown.

AIM

To explore the effect and underlying mechanisms of S100A1 in restoring erectile function in type I diabetic rat model.

METHODS

Diabetes was induced by intraperitoneal injection of streptozotocin and then screened by apomorphine (APO) to confirm erectile dysfunction. Rats that met the criteria of penile erection were marked as APO-positive; otherwise, the result was APO-negative. In experiment 1, S100A1 gene expression alterations in the corpus cavernosum in moderate and established stages of DED were analyzed. In experiment 2, S100A1 and control GFP gene were delivered into the corpus cavernosum in APO-negative rats by adeno-associated virus (AAV) serotype 9. Erectile function was assessed at 4 weeks after gene therapy.

MAIN OUTCOME MEASURES

Erectile response, histologic and molecular alterations.

RESULTS

S100A1 protein was localized to the area surrounding the cavernosal sinusoids in the penis, and it was gradually downregulated synchronized with the progression of DED. Compared with an injection of AAV-GFP, a single injection of AAV-S100A1 significantly restored erectile function in diabetic rats. S100A1 overexpression significantly upregulated the expression of endogenous VEGF-A, promoted VEGFR2 internalization, and subsequently triggered the protein kinase B-endothelial nitric oxide synthase pathway in diabetic erectile tissues. Marked increases in nitric oxide and endothelial content were noted in AAV-S100A1-treated diabetic rats.

CLINICAL IMPLICATIONS

Local S100A1 overexpression may be an alternative therapy for DED and should be further investigated by future clinical studies.

STRENGTH & LIMITATIONS

This is the first study demonstrating the angiogenic role of S100A1 in DED, but does not preclude the contribution of the effects of S100A1 in other tissues such as the neuronal tissue on the functional effects observed in erectile responses.

CONCLUSION

The decreased expression of S100A1 during hyperglycemia might be important in the development of erectile dysfunction. S100A1 may play a potential role in restoring erectile function in rats with DED through modulating cavernous angiogenesis. Yu Z, Zhang Y, Tang Z, et al. Intracavernosal Adeno-Associated Virus-Mediated S100A1 Gene Transfer Enhances Erectile Function in Diabetic Rats by Promoting Cavernous Angiogenesis via VEGF-A/VEGFR2 Signaling. J Sex Med 2019;16:1344-1354.

The predictive value of red cell distribution width on erectile dysfunction

Red cell distribution width (RDW), one of the biomarkers used to measure vascular ageing, is known to correspond with cardiovascular diseases. As coronary artery disease and erectile dysfunction (ED) are both caused by the same shared pathophysiology, in this study, we compared the RDW values of men diagnosed with ED and those of healthy controls. Ninety-nine patients who were diagnosed with ED were included in the study. The control group consists of 100 men who presented to our outpatient clinic. Patients' fasting blood glucose, triglyceride, total cholesterol and LDL cholesterol levels were significantly higher in men diagnosed with ED. While the mean RDW value was 13.49 ± 1.52 in men with ED, it was 12.91 ± 1.13 in the control group. When RDW values were compared between the two groups, the RDW values of men with ED were found to be statistically significantly higher. Multivariate analyses showed that only the patients' body mass index, fasting blood sugar, triglyceride (TG), low-density lipoprotein cholesterol, high-density lipoprotein cholesterol levels (HDL-C), TG/HDL-C ratio and RDW levels' relationship with ED was statistically significant. Although some studies have shown that RDW may be related to some diseases such as cardiovascular diseases and cancer, this appears to be the first study demonstrating a relationship between RDW and ED. RDW can be utilised as a predictor for the determination of the presence and monitoring of the severity of ED.

Multiple PDE5Is use as a marker of decreased overall men's health: A real-life study

Erectile dysfunction (ED) is considered a sentinel marker for poor general men’s health status. Severe ED has been associated with poor response to phosphodiesterase type 5 inhibitors (PDE5Is) therapy. We sought to assess the association of multiple PDE5Is prescription with the overall patients’ health status. Socio-demographic and clinical variables from 939 consecutive white–European, heterosexual, sexually-active men seeking medical help for ED at same tertiary-referral academic outpatient clinic were analyzed. Health-significant comorbidities were scored with the Charlson Comorbidity Index (CCI). Patients have been stratified into naïve and non-naïve according to their history of previous prescriptions of any PDE5I. Every patient completed the International Index of Erectile Function (IIEF) questionnaire. Logistic regression models tested the association between patients’ baseline characteristics (thus including previous PDE5Is prescriptions) and the overall health status. Overall, 328 (35%) patients were non-naïve for PDE5Is. Of them, 172 (52%), 99 (30%), and 57 (17%) had been prescribed with 1, 2 or 3 different PDE5Is, respectively. Naïve and non-naïve patients did not differ in terms of age, BMI, baseline ED severity; conversely, non-naïve patients had a higher CCI score. At logistic MVA, the number of PDE5Is prescriptions emerged as an independent predictor of a higher burden of comorbidities regardless of ED severity; the higher the number of PDE5Is prescriptions, the higher the CCI score (OR 1.69, 2.49, and 2.90 for 1, 2 or 3 previous PDE5Is, respectively), after accounting for age, BMI, baseline ED severity and cigarette smoking. More than a third of patients seeking medical help for ED at a single tertiary-referral center were non-naïve for PDE5Is. The increasing number of previous prescriptions of PDE5Is emerged as a worrisome marker of a poorer overall men’s health status regardless of ED severity.

Implanted Muscle-Derived Stem Cells Ameliorate Erectile Dysfunction in a Rat Model of Type 2 Diabetes, but Their Repair Capacity Is Impaired by Their Prior Exposure to the Diabetic Milieu

INTRODUCTION

Muscle-derived stem cells (MDSCs) and other SCs implanted into the penile corpora cavernosa ameliorate erectile dysfunction in type 1 diabetic rat models by replenishing lost corporal smooth muscle cells (SMCs) and decreasing fibrosis. However, there are no conclusive data from models of type 2 diabetes (T2D) and obesity.

AIM

To determine whether MDSCs from obese Zucker (OZ) rats with T2D at an early stage of diabetes (early diabetic SCs isolated and cultured in low-glucose medium [ED-SCs]) counteract corporal veno-occlusive dysfunction and corporal SMC loss or lipo-fibrosis when implanted in OZ rats at a late stage of diabetes and whether MDSCs from these OZ rats with late diabetes (late diabetic SCs isolated and cultured in high-glucose medium [LD-SC]) differ from ED-SCs in gene transcriptional phenotype and repair capacity.

METHODS

ED-SCs and LD-SCs were compared by DNA microarray assays, and ED-SCs were incubated in vitro under high-glucose conditions (ED-HG-SC). These three MDSC types were injected into the corpora cavernosa of OZ rats with late diabetes (OZ/ED, OZ/LD, and OZ/ED-HG rats, respectively). Untreated OZ and non-diabetic lean Zucker rats functioned as controls. Two months later, rats were subjected to cavernosometry and the penile shaft and corporal tissues were subjected to histopathology and DNA microarray assays.

MAIN OUTCOME MEASURES

In vivo erectile dysfunction assessment by Dynamic Infusion Cavernosometry followed by histopathology marker analysis of the penile tissues.

RESULTS

Implanted ED-SCs and ED-HG-SCs improved corporal veno-occlusive dysfunction, counteracted corporal decreases in the ratio of SMCs to collagen and fat infiltration in rats with long-term T2D, and upregulated neuronal and endothelial nitric oxide. LD-SCs acquired an inflammatory, pro-fibrotic, oxidative, and dyslipidemic transcriptional phenotype and failed to repair the corporal tissue.

CONCLUSION

MDSCs from pre-diabetic rats injected into the corpora cavernosa of rats with long-term T2D improve corporal veno-occlusive dysfunction and the underlying histopathology. In contrast, MDSCs from rats with long-term uncontrolled T2D are imprinted by the hyperglycemic and dyslipidemic milieu with a noxious phenotype associated with an impaired tissue repair capacity. SCs affected by diabetes could lack tissue repair efficacy as autografts and should be reprogrammed in vitro or substituted by SCs from allogenic non-diabetic sources.

Relation Between Erectile Dysfunction and Silent Myocardial Ischemia in Diabetic Patients: A Multidetector Computed Tomographic Coronary Angiographic Study

INTRODUCTION

Erectile dysfunction (ED) can precede coronary artery disease. In addition, silent myocardial ischemia (SMI) is more common in diabetic patients and is a strong predictor of cardiac events and death.

AIM

To evaluate the presence of SMI in patients with diabetes and ED using multidetector computed tomographic coronary angiography (MDCT-CA).

METHODS

This study evaluated patients with diabetes and ED without any history of cardiac symptoms or signs. Erectile function was evaluated with the Sexual Health Inventory for Men score, erection hardness score (EHS), and maximal penile circumferential change by an erectometer. MDCT-CA was used for the detection of coronary artery stenosis.

MAIN OUTCOME MEASURES

Sexual Health Inventory for Men score, EHS, maximal penile circumferential change, and coronary artery stenosis by MDCT-CA.

RESULTS

Of 20 patients (mean age = 61.45 ± 10.7 years), MDCT-CA showed coronary artery stenosis in 13 (65%) in the form of one-vessel disease (n = 6, 30%), two-vessel disease (n = 2, 10%), and three-vessel disease (n = 5, 25%). Fifty percent of patients showed at least 50% vessel lumen obstruction of the left anterior descending coronary artery, which was the most commonly affected vessel (55%). Fifteen percent (3 of 20) of patients had greater than 90% stenosis, and two of them underwent an immediate coronary angioplasty with stenting to prevent myocardial infarction. Maximum coronary artery stenosis was positively correlated with age (P = 0.016, r = 0.529) and negatively correlated with EHS (P = .046, r = -0.449). Multivariate regression analysis using age and EHS showed that age was the only independent predictor of SMI (P = .04).

CONCLUSION

MDCT-CA can be a useful tool to identify SMI in diabetic patients with ED, especially in those of advanced age and/or with severe ED.

Molecular mechanisms associated with diabetic endothelial-erectile dysfunction

Erectile dysfunction (ED) is a common complication of diabetes, affecting up to 75% of all diabetic men. Although the aetiology of diabetic ED is multifactorial, endothelial dysfunction is recognized as a mainstay in the pathophysiology of the disease. Endothelial dysfunction is induced by the detrimental actions of high glucose levels and increased oxidative stress on endothelial cells that make up the vascular lining. Besides directly injuring the endothelium, diabetes might also hamper vascular repair mechanisms of angiogenesis and vasculogenesis. These states exacerbate and maintain endothelial dysfunction, impairing vasorelaxation events and cavernosal blood perfusion, which are crucial for normal erectile function.

PnPP-19, a Synthetic and Nontoxic Peptide Designed from a Phoneutria nigriventer Toxin, Potentiates Erectile Function via NO/cGMP

PURPOSE

We designed a peptide, PnPP-19, comprising the potential active core of the Phoneutria nigriventer native toxin PnTx2-6. We investigated its role on erectile function, and its toxicity and immunogenicity.

MATERIALS AND METHODS

Erectile function was evaluated by the intracavernous pressure-to-mean arterial pressure ratio during electrical field stimulation on rat pelvic ganglia. Cavernous strips were contracted with phenylephrine and relaxation was induced by electrical field stimulation with or without PnPP-19 (10(-8) M). Activity on sodium channels was evaluated by electrophysiological screening of transfected channels on Xenopus oocytes and dorsal root ganglion cells. Antibodies were detected by indirect enzyme-linked immunosorbent assay in mice previously treated with the peptide. Histopathological studies were performed with mouse organs treated with different doses of PnPP-19.

RESULTS

PnPP-19 was able to potentiate erection at 4 and 8 Hz in vivo and ex vivo. It showed no toxicity and low immunogenicity in mice, and did not affect sodium channels or rat hearts. PnPP-19 increased cyclic guanosine monophosphate levels at 8 Hz. This effect was inhibited by L-NAME (10(-4) M). Erectile function was partially inhibited by 7-nitroindazole (10(-5) M), a selective inhibitor of neuronal nitric oxide synthase.

CONCLUSIONS

PnPP-19 potentiates erection in vivo and ex vivo via the nitric oxide/cyclic guanosine monophosphate pathway. It does not affect sodium channels or rat hearts and shows no toxicity and low immunogenicity. These findings make it a promising candidate as a novel drug in the therapy of erectile dysfunction.

Circulating endothelial progenitor cells in type 1 diabetic patients with erectile dysfunction

Circulating endothelial progenitor cells (EPCs) are bone marrow-derived stem cells able to migrate to sites of damaged endothelium and differentiate into endothelial cells, thereby contributing to vascular repair. Recent studies demonstrated a reduction of EPCs in patients with diabetes mellitus or erectile dysfunction (ED). The aim of this study was to evaluate the circulating levels of different EPCs phenotypes and their relation with testosterone levels in young type 1 diabetic patients with ED. We studied 118 consecutively type 1 diabetic patients and 60 age-matched healthy controls. Erectile function was assessed by completing the International Index of Erectile Function (IIEF-5) and EPCs levels by flow cytometry. Testosterone concentrations were evaluated in all the study population. We identified 38 diabetic patients with ED (Group 1) and 80 patients without ED (Group 2). CD34+KDR+CD133+ cells were significantly lower in patients in Group 1 as compared with those in Group 2 [median and interquartile range, n/10(6) events, 12 (6-16) vs. 18 (13-22), P < 0.001)]. In all participants in the study, there was a significant correlation between circulating CD34+KDR+CD133+ cells and testosterone levels (r = 0.410, P < 0.001), which was highest in Group 1, intermediate in Group 2, and lowest in Group 3 (controls). There was a significant correlation between IIEF-5 score and both CD34+KDR+ (r = 0.459, P = 0.003) and CD34+KDR+CD133+ (r = 0.316, P = 0.050) cells among patients of Group 1, as well as between testosterone levels and most of the EPCs phenotypes. Finally, multivariate regression analysis identified levels of circulating CD34+KDR+ cells as an independent risk factor for ED (β-coefficient 0.348, P = 0.007). In conclusion, type 1 diabetic patients with ED show reduced levels of CD34+KDR+CD133+ cells, whose number correlates with IIEF. Further studies are needed to fully understand the exact mechanisms by which testosterone regulates vascular homeostasis.

Endocrine evaluation of erectile dysfunction

Erectile dysfunction is highly prevalent, affecting up to half of men in their 50-70s, and has been variably associated to a variety of causes including unhealthy lifestyles, such as smoking or overweight, or comorbidities such as hypertension, diabetes mellitus, and neurological disorders. General interest toward ED has exploded since the introduction of phosphodiesterase type 5 inhibitors-oral drugs that are widely accepted as the first line treatment in patients suffering from this conditions. In the last decade, the time lapse between first symptoms of sexual disorders and seeking of medical advice has greatly reduced. Unfortunately, none of the PDE5i has been proven curative, but rather acts as a symptomatic treatment. The availability of very active and safe drugs, however, diminished the space for diagnosis and search of etiological treatments. This is particularly true for the several endocrinopathies associated with ED. A number of epidemiological data support an inverse relationship between sexual health and testosterone levels, and it is well accepted that testosterone deficiency is a good marker of sexual and physical frailty. However, several other hormones, including LH, prolactin, TSH, and FT4 are involved in sexual functioning and should be investigated in a proper work-out of ED. Existing guidelines provide information almost entirely focusing on late-onset hypogonadism and therapeutic strategies; this mini-review aims to provide a wider spectrum of the diagnostic endocrine work-out of ED patients unrevealing the complexity of conditions, overt or subclinical, which can affect ED.

The effect of statins on erectile dysfunction: a meta-analysis of randomized trials

INTRODUCTION

Erectile dysfunction (ED) is common in older men, especially those with comorbidities such as diabetes and atherosclerotic disease, conditions where statins are frequently prescribed.

AIM

To examine the effect of statin therapy on ED using the five-item version of the International Inventory of Erectile Function (IIEF).

METHODS

We performed a random-effects meta-analysis of studies identified by a systematic search of MEDLINE, Web of Knowledge, the Cochrane Database, and ClinicalTrials.gov. Examination of the 186 retrieved citations resulted in the selection of 11 randomized trials for inclusion in the meta-analysis.

MAIN OUTCOME MEASURES

Change in the IIEF score.

RESULTS

IIEF increased by 3.4 points (95% CI 1.7-5.0, P = 0.0001) with statins compared to control. This effect remained statistically significant after multiple sensitivity analyses, including analysis for publication bias, a cumulative meta-analysis, and 11 repeated analyses with each study omitted sequentially. The increase in IIEF with statins was approximately one-third to one-half of that previously reported with phosphodiesterase-5 inhibitors and larger than the effect of lifestyle modification. Metaregression showed an increase in benefit with decreasing lipophilicity. The average age of participants and the degree of LDL cholesterol lowering did not alter the effect on IIEF.

CONCLUSION

Statins cause a clinically relevant improvement of erectile function as measured by the five-item version of the IIEF.

Pharmacologic therapy for erectile dysfunction and its interaction with the cardiovascular system

Phosphodiesterase (PDE) enzymes are widely distributed throughout the body, having numerous effects and functions. The PDE type 5 (PDE5) inhibitors are widely used to treat erectile dysfunction (ED). Recent, intense preclinical and clinical research with PDE5 inhibitors has shed light on new mechanisms and has revealed a number of pleiotropic effects on the cardiovascular (CV) system. To date, PDE5 inhibition has been shown to be effective for the treatment of idiopathic pulmonary arterial hypertension, and both sildenafil and tadalafil are approved for this indication. However, current or future PDE5 inhibitors have the potential of becoming clinically useful in a variety of CV conditions such as heart failure, coronary artery disease, and hypertension. The present review discusses recent findings regarding pharmacologic treatment of ED and its interaction with the CV system and highlights current and future clinical applications beyond ED.

Sexual dysfunction as a marker of cardiovascular disease in males with 50 or more years of type 1 diabetes

OBJECTIVE

Vascular dysfunction is a major contributor to diabetes complications. It is also the primary physiologic cause of erectile dysfunction and considered an independent predictor of cardiovascular disease (CVD) in males over age 40 years. A cohort of individuals with 50 or more years of type 1 diabetes, Joslin Medalists, have low rates of small but not large vessel complications. This study aims to identify the prevalence and longitudinal association of sexual dysfunction (SD) with CVD in Joslin Medalists.

RESEARCH DESIGN AND METHODS

Description and association of self-assessment of SD in males of the Medalist cohort by self-reported sexual problems with CVD. SD is validated through the use of the abbreviated International Index of Erectile Dysfunction (IIEF).

RESULTS

Of 301 males in the Medalist Study, 69.8% reported a history of SD. Unadjusted risk factors included elevated glycated hemoglobin (HbA1c) (P=0.02), elevated BMI (P=0.03), higher total cholesterol (P=0.02), lower HDL (P<0.01), and increased levels of interleukin-6 (P=0.03). SD was independently associated with CVD (age-, HbA1c-, and BMI-adjusted OR 1.9 [95% CI 1.0-3.5]). In adjusted analyses, retinal, neural, and renal complications were not associated (P>0.05) with SD. Current report of SD (IIEF score≤17) in a subset of Medalists was significantly correlated with self-reported longitudinal SD.

CONCLUSIONS

SD in those with extreme-duration type 1 diabetes is independently associated with CVD, representing a large-vessel pattern. The findings suggest that SD may predict CVD in those with type 1 diabetes of long duration. These individuals have also been found to be relatively free of microvascular complications.

Is erectile dysfunction a reliable indicator of general health status in men?

Introduction

Erectile dysfunction (ED) is a common risk factor in men and its incidence increases with age. Ageing and older men frequently have comorbidities such as cardiovascular diseases (CVD), diabetes mellitus (DM), hypertension, chronic obstructive pulmonary disease and dyslipidaemia; likewise, they concurrently refer to a clinician for impairments in sexual function, mostly for ED. The association of ED and other organic, multi-organic or even systemic diseases is widely described, with a specific emphasis on the fact that they often share common pathophysiological factors and mechanisms. Thus we reviewed previous reports assessing the role of ED as a sentinel marker of overall men’s health.

Discussion

ED is considered an important sentinel marker for CVD. Numerous studies have highlighted the predictive role of ED for subsequent CV events in patients with a silent history of coronary artery disease. Indeed, ED might be considered as a clinical manifestation of a generalised vascular disease, and it should provoke clinicians to check for CVDs in those patients complaining of impaired erectile function. This concept appears to be even more important for men with DM, where ED has already been shown to have a significant predictive ability for major vascular complications. Moreover, data from large population-based studies showed that ED is a significant predictor of all-cause mortality, in addition to CV outcomes. The severity of erectile function is assessed with the International Index of Erectile Function-Erectile Function domain score, and this has emerged as a proxy for men’s general health status, as assessed with the Charlson Comorbidity Index score.

Conclusions

Patients complaining of ED should be evaluated with a comprehensive medical and sexual history, and a thorough physical examination, regardless of their age, considering ED as an opportunity to screen for the presence of health-threatening concomitant comorbidities.

A systematic review of the association between erectile dysfunction and cardiovascular disease

CONTEXT

Erectile dysfunction (ED) is considered a vascular impairment that shares many risk factors with cardiovascular disease (CVD). A correlation between ED and CVD has been hypothesized, and ED has been proposed as an early marker of symptomatic CVD.

OBJECTIVE

To analyze the relationship between ED and CVD, evaluating the pathophysiologic links between these conditions, and to identify which patients would benefit from cardiologic assessment when presenting with ED.

EVIDENCE ACQUISITION

A systematic literature review searching Medline, Embase, and Web of Science databases was performed. The search strategy included the terms erectile dysfunction, cardiovascular disease, coronary artery disease, risk factors, pathophysiology, atherosclerosis, low androgen levels, inflammation, screening, and phosphodiesterase type 5 inhibitors alone or in combination. We limited our search to studies published between January 2005 and May 2013.

EVIDENCE SYNTHESIS

Several studies reported an association between ED and CVD. The link between these conditions might reside in the interaction between androgens, chronic inflammation, and cardiovascular risk factors that determines endothelial dysfunction and atherosclerosis, resulting in disorders of penile and coronary circulation. Because penile artery size is smaller compared with coronary arteries, the same level of endothelial dysfunction causes a more significant reduction of blood flow in erectile tissues compared with that in coronary circulation. Thus ED could be an indicator of systemic endothelial dysfunction. From a clinical standpoint, because ED may precede CVD, it can be used as an early marker to identify men at higher risk of CVD events. ED patients at high risk of CVD should undergo detailed cardiologic assessment and receive intensive treatment of risk factors.

CONCLUSIONS

ED and CVD should be regarded as two different manifestations of the same systemic disorder. ED usually precedes CVD onset, and it might be considered an early marker of symptomatic CVD.

Chronic treatment with taurine ameliorates diabetes-induced dysfunction of nitric oxide-mediated neurogenic and endothelium-dependent corpus cavernosum relaxation in rats

This study was aimed to examine the effect of chronic taurine treatment on corpus cavernosum dysfunction in diabetic rats and to investigate possible underlying mechanisms. Thirty male rats were randomized to three groups of 10 each, including control, diabetic, and taurine-treated diabetic. Diabetes was induced in rats by streptozotocin (STZ, single intraperitoneal dose of 50 mg/kg body weight). Taurine was administered orally for 12 weeks (1% w/v in drinking water) from the day on which STZ was injected. At the end of the 12th week, strips of corpus cavernosum were suspended in an organ bath system for functional studies. Nitric oxide (NO)-mediated endothelium-dependent and neurogenic corpus cavernosum relaxation were evaluated by acetylcholine (ACh, 0.1-100 μm) and electrical field stimulation (EFS, 30 V, 5 ms, 2-32 Hz), respectively. The expressions of endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (p-eNOS) (Ser-1177), neuronal nitric oxide synthase (nNOS), NADPH oxidase subunit gp91(phox) , Rho A, and Rho kinase in corpus cavernosum were semi-quantitatively assessed by immunohistochemistry. Induction of diabetes resulted in significant inhibition of NO-mediated endothelium-dependent and neurogenic corpus cavernosum relaxation. Furthermore, eNOS, p-eNOS, and nNOS expressions decreased significantly in diabetic rats compared to controls, while gp91(phox) , RhoA and Rho kinase expressions increased significantly. The diminished relaxation response to ACh and EFS as well as diabetes-related changes in expressions of these proteins in corpus cavernosum of diabetic rats was significantly improved by taurine. Taurine treatment improves NO-mediated relaxations of corpus cavernosum in diabetic rats probably by inhibiting NADPH oxidase/Rho kinase pathways.