Plasma levels of endothelin-1, angiotensin II, nitric oxide and prostaglandin E2 in the venous and cavernosal blood of patients with erectile dysfunction

Cardiometabolic Disorder and Erectile Dysfunction

Erectile dysfunction (ED), which is defined as the inability to attain and maintain a satisfactory penile erection to sufficiently permit sexual intercourse, is a consequence and also a cause of cardiometabolic disorders like diabetes mellitus, systemic hypertension, central obesity, and dyslipidemia. Although there are mounting and convincing pieces of evidence in the literature linking ED and cardiometabolic disorders, impairment of nitric oxide-dependent vasodilatation seems to be the primary signaling pathway. Studies have also implicated the suppression of circulating testosterone, increased endothelin-1, and hyperactivation of Ang II/ATIr in the pathogenesis of ED and cardiometabolic disorders. This study provides comprehensive details of the association between cardiometabolic disorders and ED and highlights the mechanisms involved. This would open areas to be explored as therapeutic targets in the management of ED and cardiometabolic disorders. It also provides sufficient evidence establishing the need for the management of cardiometabolic disorders as an adjunct therapy in the management of ED.

Association between neutrophil to lymphocyte ratio and erectile dysfunction among US males: a population-based cross-sectional study

Objective

The purpose of the study was to investigate the relationship between neutrophil-to-lymphocyte ratio (NLR) and erectile dysfunction (ED) in adult American males using a large database.

Methods

We adopted a series of statistical analyses of the relationship between NLR indices and ED prevalence among participants in the 2001-2004 National Health and Nutrition Examination Survey (NHANES) database using the R software.

Results

The study included a total of 3012 participants, of whom 570 (18.9%) presented with ED. NLR levels were 2.13 (95% CI: 2.08,2.17) in those without ED and 2.36 (95% CI: 2.27,2.45) in those with ED. After adjusting for confounding variables, NLR levels were higher in patients with ED, (β, 1.21, 95% CI, 1.09-1.34, P < 0.001). In addition, a U-shaped relationship between NLR and ED was observed after controlling for all confounders. A more significant correlation (β, 1.35, 95% CI, 1.19 to 1.53, P < 0.001) existed to the right of the inflection point (1.52).

Conclusion

The results of the large cross-sectional study showed a statistically significant association between the occurrence of ED and NLR, a simple, inexpensive, and readily available parameter of inflammation, in US adults. Further studies are still needed in the future to validate and replicate our findings and to investigate the specific mechanisms involved.

Efficacy of Yougui pill combined with Buzhong Yiqi decoction in alleviating the sexual dysfunction in female rats through modulation of the gut microbiota

CONTEXT

Yougui pill combined with Buzhong Yiqi decoction (YPBYD) is used to relieve sexual dysfunction in clinical practice.

OBJECTIVE

To investigate changes in microbial composition caused by sexual dysfunction and identify dominant bacteria related to YPBYD treatment.

MATERIALS AND METHODS

Female Sprague-Dawley rats were randomly divided into four groups (n = 6): one group underwent Sham operation (Sham group), while three groups underwent ovariectomy (one model and two treatment groups). The ovariectomized (OVX) rats received oestradiol benzoate (250 µg/kg/week) or YPBYD (3.6 mL/d) via oral gavage for 4 weeks. Vaginal smear assay was performed; the serum levels of cyclic adenosine monophosphate (cAMP) and oestradiol (E2) were measured, followed by collection of stool samples for 16S rRNA sequencing.

RESULTS

After YPBYD treatment, the levels of E2 and cAMP in OVX rats significantly increased (E2: from 20.45 ± 1.60 ng/L to 24.38 ± 1.70 ng/L; cAMP: from 261.41 ± 9.21 pg/mL to 373.75 ± 17.37 pg/mL). OVX treatment decreased diversity of gut microbiota and YPBYD treatment restored gut microbiota composition. Compared with Sham group, the abundance of Romboutsia significantly increased, while those of Proteobacteria and Staphylococcus markedly decreased in OVX group (all p < 0.05); meanwhile, the abundance of these microbes showed an opposite trend after YPBYD treatment. These microbiotas were involved in tyrosine and tryptophan biosynthesis and fatty acid metabolism.

DISCUSSION AND CONCLUSIONS

These findings are the first to indicate YPBYD can alleviate female sexual dysfunction by modulating gut microbiota in OVX rats, which will help enhance the understanding on potential mechanism of YPBYD against sexual dysfunction.

ET-1 as a Sex-Specific Mechanism Impacting Age-Related Changes in Vascular Function

Aging is a primary risk factor for cardiovascular disease (CVD), which is the leading cause of death in developed countries. Globally, the population of adults over the age of 60 is expected to double by the year 2050. CVD prevalence and mortality rates differ between men and women as they age in part due to sex-specific mechanisms impacting the biological processes of aging. Measures of vascular function offer key insights into cardiovascular health. Changes in vascular function precede changes in CVD prevalence rates in men and women and with aging. A key mechanism underlying these changes in vascular function is the endothelin (ET) system. Studies have demonstrated sex and sex hormone effects on endothelin-1 (ET-1), and its receptors ETA and ETB. However, with aging there is a dysregulation of this system resulting in an imbalance between vasodilation and vasoconstriction. Thus, ET-1 may play a role in the sex differences observed with vascular aging. While most research has been conducted in pre-clinical animal models, we describe more recent translational data in humans showing that the ET system is an important regulator of vascular dysfunction with aging and acts through sex-specific ET receptor mechanisms. In this review, we present translational evidence (cell, tissue, animal, and human) that the ET system is a key mechanism regulating sex-specific changes in vascular function with aging, along with therapeutic interventions to reduce ET-mediated vascular dysfunction associated with aging. More knowledge on the factors responsible for the sex differences with vascular aging allow for optimized therapeutic strategies to attenuate CVD risk in the expanding aging population.

Endothelial Dysfunction and Ischemia-Modified Albumin Levels in Males with Diabetic and Nondiabetic Erectile Dysfunction

In this study, we aimed to determine endothelial dysfunction and ischemia-modified albumin (IMA) levels in patients diagnosed with erectile dysfunction (ED) and to examine the relationship between these and diabetes disease. 86 male patients (46 patients with diabetes, age: $51.5\pm 9.2$ and 40 patients with nondiabetes (control group), age: $54.78\pm 12.2$ ) were included in the study. IMA, a new indicator of tissue ischemia and oxidative stress, was checked. Superoxide dismutase (SOD) activity, another oxidative stress indicator, was examined. Endothelin-1 (ET-1), one of the parameters of endothelial dysfunction, was measured. Additionally, endothelial function was evaluated with flow-mediated vasodilatation (FMD). Student’s $t$ -test was used for statistical evaluation. $p$ values less than 0.05 were considered statistically significant. SOD activity was significantly lower in the diabetic group than in the control group, and ET-1 was significantly higher ( $p<0.001$ ). IMA was found to be significantly higher in the diabetic group than the control group ( $p<0.001$ ). FMD was significantly lower in diabetic group compared to the control group ( $p<0.002$ ). According to our findings, the co-occurrence of erectile dysfunction and diabetes demonstrates a complex condition that includes endothelial dysfunction, oxidative stress, and tissue ischemia. When the correlation of indicators, which are markers, was examined, the severity of the co-occurrence of diabetes and erectile dysfunction was again demonstrated.

Hypertension and Erectile Dysfunction: Breaking Down the Challenges

A diagnostic of hypertension increases the risk of erectile dysfunction (ED); likewise, ED can be an early sign of hypertension. In both cases, there is evidence that endothelial dysfunction is a common link between the 2 conditions. During hypertension, the sustained and widespread release of procontractile factors (e.g., angiotensin II, endothelin 1, and aldosterone) impairs the balance between vasoconstrictors and vasodilators and, in turn, detrimentally impacts vascular and erectile structures. This prohypertensive state associates with an enhancement in the generation of reactive oxygen species, which is not compensated by internal antioxidant mechanisms. Recently, the innate immune system, mainly via Toll-like receptor 4, has also been shown to actively contribute to the pathophysiology of hypertension and ED not only by inducing oxidative stress but also by sustaining a low-grade inflammatory state. Furthermore, some drugs used to treat hypertension can cause ED and, consequently, reduce compliance with the prescribed pharmacotherapy. To break down these challenges, in this review, we focus on discussing the well-established as well as the emerging mechanisms linking hypertension and ED with an emphasis on the signaling network of the vasculature and corpora cavernosa, the vascular-like structure of the penis.

Spondias mombim L. (Anacardiaceae): Chemical fingerprints, inhibitory activities, and molecular docking on key enzymes relevant to erectile dysfunction and Alzheimer's diseases

Due to the exceptional wide range in biochemical activities of natural plant products, Spondias mombim L. are attaining a new height because they present great prospects for drug advancement. This research was designed to analyze the pharmaceutical properties of S. mombim L. ethyl acetate fraction (SMEAF) on key enzymes relevant to erectile and cognitive dysfunction. SMEAF inhibitory activities of the specified enzymes were determined spectrophotometrically. Chemical profile of SMEAF were assessed by HPLC/MS analysis. Thereafter, molecular docking of the studied enzymes with chlorogenic acid, lutein, and zeaxanthin were carried out using PATCHDOCK. SMEAF had remarkable enzyme inhibitory effects against phosphodiesterase-5 (PDE-5), arginase, angiotensin I-converting enzyme (ACE), cholinesterase, monoamine oxidase A (MAO), ecto-5' nucleotidase (E-NTDase), tyrosinase, and stimulated sodium-potassium ATPase (Na+/K+-ATPase) activities. HPLC/MS analysis revealed that phenolics and carotenoids were major components in these fraction notably, chlorogenic acid, lutein, and zeaxanthin. Our results suggested that SMEAF could be explored as phytopharmaceuticals. PRACTICAL APPLICATIONS: Spondias mombim L. are cooked as green vegetable with enormous medicinal value probably due to its polyphenols with potent antioxidant activity. Furthermore, the leaves could also be useful for therapeutic purposes against erectile dysfunction and central nervous system disorders.

Expression profile of endothelin receptors (ETA and ETB) and microRNAs-155 and -199 in the corpus cavernosum of rats submitted to chronic alcoholism and diabetes mellitus

Recent evidence shows that chronic ethanol consumption increases endothelin (ET)-1 induced sustained contraction of trabecular smooth muscle cells of the corpora cavernosa in corpus cavernosum of rats by a mechanism that involves increased expression of ETA and ETB receptors. Our goal was to evaluate the effects of alcohol and diabetes and their relationship to miRNA-155, miRNA-199 and endothelin receptors in the corpus cavernosum and blood of rats submitted to the experimental model of diabetes mellitus and chronic alcoholism. Forty-eight male Wistar rats were divided into four groups: control (C), alcoholic (A), diabetic (D), and alcoholic-diabetic (AD). Samples of the corpus cavernosum were prepared to study the protein expression of endothelin receptors by immunohistochemistry and expression of miRNAs-155 and -199 in serum and the cavernous tissue. Immunostaining for endothelin receptors was markedly higher in the A, D, and AD groups than in the C group. Moreover, a significant hypoexpression of the miRNA-199 in the corpus cavernosum tissue from the AD group was observed, compared to the C group. When analyzing the microRNA profile in blood, a significant hypoexpression of miRNA-155 in the AD group was observed compared to the C group. The miRNA-199 analysis demonstrated significant hypoexpression in D and AD groups compared to the C group. Our findings in corpus cavernosum showed downregulated miRNA-155 and miRNA-199 levels associated with upregulated protein expression and unaltered mRNA expression of ET receptors suggesting decreased ET receptor turnover, which can contribute to erectile dysfunction in diabetic rats exposed to high alcohol levels.

Role of endothelin receptors and relationship with nitric oxide synthase in impaired erectile response in diabetic rats

To evaluate the protective role of bosentan (BOS), an endothelin-1 (ET-1) receptor antagonist, and to show the changes in rats with experimentally induced diabetic erectile dysfunction (ED), a total of 24 albino Wistar rats were allocated into four groups. Group 1 was the healthy group and Group 2 had diabetes mellitus (DM) induced by intraperitoneal injection of 60 mg kg^-1 streptozotocin (STZ). Following the establishment of DM, Group 3 and Group 4 were treated with oral BOS doses of 50 mg kg^-1 and 100 mg kg^-1 , respectively, for 60 days. At the end of the treatment, we evaluated yawning and erection response to apomorphine treatment and then the animals were sacrificed. ET-1, eNOS, iNOS, tumour necrosis factor (TNF)-α, ET-RA and ET-RB mRNA expressions were analysed in cavernosal tissue. It was observed that yawning and erection response decreased in the diabetic group; however, both of these improved with BOS treatment. While ET-1, TNF-α and iNOS gene expressions increased, eNOS, ET-RA and ET-RB gene expressions decreased in the DM group compared to the healthy group. DM has a negative impact on cavernosal tissue blood flow through activating vasoconstrictor mediators in cavernosal tissue. BOS regulates significantly eNOS, iNOS and TNF-α expressions in a dose-dependent manner.

The Investigation of Relationship between Coronary Artery Ectasia, Benign Prostatic Enlargement, and Lower Urinary Tract Symptoms

OBJECTIVE

To investigate benign prostatic enlargement (BPE) and lower urinary tract symptoms (LUTS) in patients with coronary artery ectasia (CAE). The relation between CAE, BPE, and LUTS has not been studied so far.

METHODS

We investigated BPE and LUTS symptoms in 47 men with CAE, 45 men with coronary artery disease (CAD), and 47 male controls with normal coronary arteries. LUTS was evaluated by the International Prostate Symptom Score (IPSS). BPE was evaluated with transabdominal ultrasonography. CAD was defined as myocardial infarction and angiographically diagnosed coronary disease. CAE was defined as being without any stenotic lesions with a visual assessment of the coronary arteries showing a luminal dilatation ≥1.5 fold of the adjacent normal coronary segments.

RESULTS

Prostate volume was higher in CAE and CAD patients compared with that of the control subjects, respectively (41.0 ± 10.4 vs 33.5 ± 9.4 cm(3); 39.1 ± 10.3 vs 33.5 ± 9.4 cm(3); P = .0001); total IPSS was higher in CAD and CAE patients compared with that of the control subjects (P = .0001). Postmictional residual urine volume was higher in CAE and CAD patients compared with that of the control subjects (P = .002).

CONCLUSION

We showed that patients with CAE have higher prostate volume, IPSS, and postmictional residual urine volume compared with those of controls with normal coronary angiograms. This study proposes that BPE, LUTS, and CAE maybe different disorders to a common vascular pathology and endothelial dysfunction. This study showed that BPE and LUTS were frequently seen in CAE at least as much as in CAD. Therefore, LUTS and BPE should be kept in mind for CAE patients in follow-ups.

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.

Erectile dysfunction

Erectile dysfunction is a common clinical entity that affects mainly men older than 40 years. In addition to the classical causes of erectile dysfunction, such as diabetes mellitus and hypertension, several common lifestyle factors, such as obesity, limited or an absence of physical exercise, and lower urinary tract symptoms, have been linked to the development of erectile dysfunction. Substantial steps have been taken in the study of the association between erectile dysfunction and cardiovascular disease. Erectile dysfunction is a strong predictor for coronary artery disease, and cardiovascular assessment of a non-cardiac patient presenting with erectile dysfunction is now recommended. Substantial advances have occurred in the understanding of the pathophysiology of erectile dysfunction that ultimately led to the development of successful oral therapies, namely the phosphodiesterase type 5 inhibitors. However, oral phosphodiesterase type 5 inhibitors have limitations, and present research is thus investigating cutting-edge therapeutic strategies including gene and cell-based technologies with the aim of discovering a cure for erectile dysfunction.

Biochemical and genetic markers of erectile dysfunction

Erectile dysfunction (ED) is a very common pathology, affecting over 150 million men worldwide. The pathogenesis is typically multifactorial, involving a kaleidoscope of organic, endocrine, and psychogenic factors. In general, ED is divided into organic and psychogenic impotence, but most men with organic etiologies have an associated psychogenic component. Given the high frequency of this pathology, the identification of biochemical and genetic correlates and/or markers is of pivotal interest not only for treating preciously these patients and preventing serious psychological consequences but also for the high risk for occult cardiovascular disease (CVD) that often accompanies or follows this pathology. A variety of cardiovascular risk factors have been associated with both the onset and the severity of ED, including markers of endothelial function, thrombosis, and especially dyslipidemia, so that their measurement should now be considered as an important part of the increased global cardiometabolic risk profile in patients with ED. While nitric oxide (NO), asymmetric dimethylarginine (ADMA), and endothelin (ET) hold some promises as biochemical markers of both CVD and ED, there are several technical and clinical drawbacks that make their measurement overall meaningless in the clinical practice. As regards genetic polymorphisms, controversial results have been provided so far. Although some genetic markers were consistently associated with ED, other studies failed to demonstrate significant associations, highlighting a substantial bias in standardization of methodologies and patient enrolment. Nevertheless, further research in this area should be encouraged, since the first promising evidence that gene therapy might be effective to restore the decline in ED has been provided in the animal model.

Is there a link between soft drinks and erectile dysfunction?

This review focuses on the potential role of soft drinks, particularly the sugar component, in the pathogenesis of erectile dysfunction (ED). We analyzed the hypothetical link between metabolic disorders, induced by sweetened soft drinks overconsumption, and ED. High caloric intake, high refined-carbohydrates, and high fructose corn syrup (HFCS) content and less satiety are main factors responsible for metabolic disorders contributing to ED development. Regular diet mistakes among human males, such as soft drink consumption, may lead to slow and asymptomatic progression of ED, finally resulting in full claimed manifestation of ED.

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

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

Markers of erectile dysfunction

With the development and marketing of oral pharmacotherapy that is both noninvasive and successful in treating erectile dysfunction (ED), the quest to identify markers of organic ED lost ground. Indeed, the multi-factorial nature of ED may have led many researchers to conclude that searching for a universal marker of ED was futile. However, the realization that ED is strongly correlated with the overall health of men, and may act as a predictor for the development of cardiovascular disease (CVD) and diabetes, has stimulated interest in identifying genes that can distinguish organic ED. In addition, the potential ability to suggest to the patient that ED is reversible (i.e., psychogenic) with a simple test would be of significance to both the physician and patient, as well as for reimbursement issues for therapy by insurance companies. Such a marker may also act as a non-subjective measure of the degree of ED and the efficacy of treatment. This review discusses the importance of identifying such markers and recent work identifying potential markers in human patients.

Future sexual medicine physiological treatment targets

INTRODUCTION

Sexual function in men and women incorporates physiologic processes and regulation of the central and peripheral nervous systems, the vascular system, and the endocrine system. There is need for state-of-the-art information as there is an evolving research understanding of the underlying molecular biological factors and mechanisms governing sexual physiologic functions.

AIM

To develop an evidence-based, state-of-the-art consensus report on the current knowledge of the major cellular and molecular targets of biologic systems responsible for sexual physiologic function.

METHODS

State-of-the-art knowledge representing the opinions of seven experts from four countries was developed in a consensus process over a 2-year period.

MAIN OUTCOME MEASURES

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

RESULTS

Scientific investigation in this field is needed to increase knowledge and foster development of the future line of treatments for all forms of biological-based sexual dysfunction. This article addresses the current knowledge of the major cellular and molecular targets of biological systems responsible for sexual physiologic function. Future treatment targets include growth factor therapy, gene therapy, stem and cell-based therapies, and regenerative medicine.

CONCLUSIONS

Scientific discovery is critically important for developing new and increasingly effective treatments in sexual medicine. Broad physiologic directions should be vigorously explored and considered for future management of sexual disorders.

Anatomy, physiology, and pathophysiology of erectile dysfunction

INTRODUCTION

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

AIM

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

METHODS

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

MAIN OUTCOME MEASURE

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

RESULTS

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

CONCLUSIONS

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

Erectile dysfunction, microangiopathy and UKPDS risk in type 2 diabetes

BACKGROUND

Erectile dysfunction (ED) is a frequent comorbidity in patients with type 2 diabetes mellitus (T2DM), and is now increasingly considered a surrogate marker of endothelial dysfunction as well as a sentinel predictor of new-onset macroangiopathic events. Less attention, however, has been directed at the potential association of ED and microangiopathy in hyperglycaemic states.

METHODS

We analyzed 221 consecutive male T2DM outpatients in whom ED was assessed by the International Index of Erectile Function (IIEF-5) questionnaire. ED(+) patients (IIEF-5 1-20; n=83) were compared with an age-matched ED(-) cohort (IIEF-5 21-25; n=51), with similar diabetes duration, in terms of cardiovascular (CV) risk factors, micro-/macroangiopathy and the United Kingdom Prospective Diabetes Study (UKPDS) risk score.

RESULTS

Mean age and diabetes duration were 58 and 10 years, respectively. IIEF-5 score (1 S.D) was 23 (1) in ED(-) vs 11 (6) in ED(+). Anamnestic impotence and erectogenic drug use were reported by 52% and 36%, respectively, of ED(+) vs 12% and 8%, respectively, of ED(-) (P<0.0002 and P<0.0001, respectively). The metabolic syndrome prevalence (88% vs 64%; P=0.002) and central adiposity markers (waist, waist/height and visceral fat) were all significantly higher in ED(+). HbA(1c) was similar in both groups: 7.5% (1.3%), and there were also no significant differences in smoking, blood pressure, HOMA insulin sensitivity, cholesterol and glomerular filtration rate. However, prevalences of retinopathy, polyneuropathy and elevated albuminuria, and the composite endpoint of peripheral artery disease, transient ischaemic attacks and/or stroke, were markedly increased in ED(+) (all P<0.05). No differences were observed in coronary artery disease prevalence or in the UKPDS 10-year CV risk between the two ED groups.

CONCLUSION

IIEF-5-defined ED in men with T2DM is associated with a marked increase in the metabolic syndrome, central adiposity and microangiopathy. These data suggest that diagnosing ED in T2DM warrants detailed screening and monitoring for microangiopathy in target organs.

The endothelial cell in health and disease: its function, dysfunction, measurement and therapy

Endothelial cells have numerous endocrine functions and contribute to a variety of processes, including penile erection and vasodilation. Endothelial dysfunction is associated with cardiovascular risk factors and has been implicated in the pathogenesis of atherosclerosis and ED. This study reviews endothelial function, in addition to endothelial dysfunction and its role in atherosclerosis and ED. Measurement of endothelial function is reviewed, including catheter-based methods, venous occlusion plethysmography, high-frequency ultrasound, peripheral arterial tonometry, digital pulse amplitude tonometry, digital thermal monitoring, the L-arginine test and measurement of compounds released by endothelial cells. Therapy and medications that improve endothelial function are reviewed. As the scientific community learns more about the importance of the endothelium, it is increasingly important for the clinician to understand endothelial function, dysfunction, measurement of endothelial function and therapies that affect this remarkable cell type.

Regulation of peripheral blood flow in complex regional pain syndrome: clinical implication for symptomatic relief and pain management

BACKGROUND

During the chronic stage of Complex Regional Pain Syndrome (CRPS), impaired microcirculation is related to increased vasoconstriction, tissue hypoxia, and metabolic tissue acidosis in the affected limb. Several mechanisms may be responsible for the ischemia and pain in chronic cold CPRS.

DISCUSSION

The diminished blood flow may be caused by either sympathetic dysfunction, hypersensitivity to circulating catecholamines, or endothelial dysfunction. The pain may be of neuropathic, inflammatory, nociceptive, or functional nature, or of mixed origin.

SUMMARY

The origin of the pain should be the basis of the symptomatic therapy. Since the difference in temperature between both hands fluctuates over time in cold CRPS, when in doubt, the clinician should prioritize the patient's report of a persistent cold extremity over clinical tests that show no difference. Future research should focus on developing easily applied methods for clinical use to differentiate between central and peripheral blood flow regulation disorders in individual patients.

No recovery of cold complex regional pain syndrome after transdermal isosorbide dinitrate: a small controlled trial

The microcirculation appears to be impaired in cold chronic complex regional pain syndrome (CRPS). This double-blind, placebo-controlled, randomized trial investigated the effect of the nitric oxide (NO) donor isosorbide dinitrate (ISDN) on the peripheral blood flow in patients with chronic CRPS. Twenty-four patients received 1% ISDN in Vaseline or a placebo ointment applied to the dorsum of the affected hand four times daily for 10 weeks. The patients participated in a physical therapy program to improve activity. The primary outcome measure was blood distribution in the affected extremity, which was determined by measuring the skin temperature using videothermography. We also measured NO and endothelin-1 concentrations in blister fluid, pain using the visual analog scale, and activity limitations using an upper limb activity monitor and the Disabilities of Arm Shoulder and Hand Questionnaire. ISDN failed to produce a significant improvement in temperature asymmetry in chronic cold CRPS patients, and it did not result in the expected reduction in pain and increase in activity compared with placebo either. There may be other central or peripheral factors contributing to the disturbed vasodynamics in cold chronic CRPS that are not influenced by NO substitution. This study does not show an improvement of the regional blood distribution by ISDN in the involved extremity of patients with cold-type CRPS.

The endothelial-erectile dysfunction connection: an essential update

INTRODUCTION

The endothelial monolayer plays a crucial role in the vasodilation and hemodynamic events involved in erection physiology. Due to its relevant functions, a close link has been established between endothelial integrity and erectile dysfunction (ED). Endothelial dysfunction is induced by the detrimental actions of vascular risk factors (VRFs), identified as common correlates for the development of cardiovascular disease and ED. It is currently recognized that ED is the early harbinger of a more generalized vascular systemic disorder, and, therefore, an evaluation of endothelial health in ED patients should be of prime relevance. Several noninvasive methods for endothelial function assessment have been proposed, including the Penile Nitric Oxide Release Test (PNORT).

AIM

To highlight the most recent gathered knowledge on basic and clinical mechanisms underlying loss of cavernosal endothelial function promoted by VRFs and to discuss local and systemic methods for endothelial function assessment in ED individuals, focusing on the PNORT.

MAIN OUTCOME MEASURES

A complete revision on the novel basic and clinical links between endothelial and ED.

METHODS

A systematic review of the literature regarding the aforementioned issues.

RESULTS

Risk factor-associated cavernosal endothelial dysfunction is mostly induced by unifying mechanisms, including oxidative stress and impaired endothelial nitric oxide functional activities, which present clinically as ED. Several techniques to evaluate endothelial dysfunction were revised, with advantages and limitations debated, focusing on our detailed expertise using the PNORT method.

CONCLUSIONS

The established endothelial-erectile dysfunction connection was thoroughly revised, from basic mechanisms to the clinical importance of endothelial dysfunction assessment as diagnosis for generalized vascular disease. Further studies are required to disclose efficient approaches to repair disabled endothelium and both restore and prevent endothelial dysfunction.

Losartan, an Angiotensin type I receptor, restores erectile function by downregulation of cavernous renin-angiotensin system in streptozocin-induced diabetic rats

INTRODUCTION

The high incidence of erectile dysfunction (ED) in diabetes highlights the need for good treatment strategies. Recent evidence indicates that blockade of the angiotensin type I receptor (AT1) may reverse ED from various diseases.

AIM

To explore the role of cavernous renin-angiotensin system (RAS) in the pathogenesis of diabetic ED and the role of losartan in the treatment of diabetic ED.

METHODS

The AT1 blocker (ARB) losartan (30 mg/kg/d) was administered to rats with streptozocin (65 mg/kg)-induced diabetes. Erectile function, cavernous structure, and tissue gene and protein expression of RAS in the corpora cavernosa were studied.

MAIN OUTCOME MEASURE

We sought to determine the changes of cavernous RAS in the condition of diabetes and after treatment with losartan.

RESULTS

RAS components (angiotensinogen, [pro]renin receptor, angiotensin-converting enzyme [ACE], and AT1) were expressed in cavernosal tissue. In diabetic rats, RAS components were upregulated, resulting in the increased concentration of angiotensin II (Ang II) in the corpora. A positive feedback loop for Ang II formation in cavernosum was also identified, which could contribute to overactivity of cavernous RAS in diabetic rats. Administration of losartan blocked the effect of Ang II, downregulated the expression of AT1 and Ang II generated locally, and partially restored erectile function (losartan-treated group revealed an improved intracavernous pressure/mean systemic arterial pressure ratio as compared with the diabetic group (0.480 +/- 0.031 vs. 0.329 +/- 0.020, P < 0.01). However, losartan could not elevate the reduced smooth muscle/collagen ratio in diabetic rats.

CONCLUSIONS

The cavernous RAS plays a role in modulating erectile function in corpora cavernosa and is involved in the pathogenesis of diabetic ED. ARB can restore diabetic ED through downregulating cavernous RAS.

DOCA-salt treatment enhances responses to endothelin-1 in murine corpus cavernosum

The penis is kept in the flaccid state mainly via a tonic activity of norepinephrine and endothelins (ETs). ET-1 is important in salt-sensitive forms of hypertension. We hypothesized that cavernosal responses to ET-1 are enhanced in deoxycorticosterone acetate (DOCA)-salt mice and that blockade of ETA receptors prevents abnormal responses of the corpus cavernosum in DOCA-salt hypertension. Male C57BL/6 mice were unilaterally nephrectomized and treated for 5 weeks with both DOCA and water containing 1% NaCl and 0.2% KCl. Control mice were uninephrectomized and received tap water with no added salt. Animals received either the ETA antagonist atrasentan (5 mg x day(-1) x kg(-1) body weight) or vehicle. DOCA-salt mice displayed increased systolic blood pressure (SBP), and treatment with atrasentan decreased SBP in DOCA-salt mice. Contractile responses in cavernosal strips from DOCA-salt mice were enhanced by ET-1, phenylephrine, and electrical field stimulation (EFS) of adrenergic nerves, whereas relaxations were not altered by IRL-1620 (an ETB agonist), acetylcholine, sodium nitroprusside, and EFS of nonadrenergic noncholinergic nerves. PD59089 (an ERK1/2 inhibitor), but not Y-27632 (a Rho-kinase inhibitor), abolished enhanced contractions to ET-1 in cavernosum from DOCA-salt mice. Treatment of DOCA-salt mice with atrasentan did not normalize cavernosal responses. In summary, DOCA-salt treatment in mice enhances cavernosal reactivity to contractile, but not to relaxant, stimuli, via ET-1/ETA receptor-independent mechanisms.

Vasodilative effect of isosorbide dinitrate ointment in complex regional pain syndrome type 1

BACKGROUND

In complex regional pain syndrome type 1 (CRPS1) vascular changes occur from the initial, inflammatory event onto the trophic signs during chronicity of the disease, resulting in blood flow disturbances and marked temperature changes. Pharmacotherapeutic treatment is generally inadequate.

AIM

To determine whether local application of the nitric oxide donor isosorbide dinitrate (ISDN) could cause vasodilation and thereby improve tissue blood distribution in the affected extremity.

METHODS

In a pilot study, 5 female patients with CRPS1 in one hand were treated with ISDN ointment 4 times daily during 10 weeks. As a primary objective videothermography was used to monitor changes in blood distribution in both the involved and contralateral extremities.

RESULTS

Patients treated with ISDN showed an increase of 4 degrees C to 6 degrees C in mean skin temperature of the cold CRPS1 hands, reaching values similar to that of the contralateral extremities within 2 to 4 weeks time, suggesting normalization of blood distribution. This was confirmed by an improvement in skin color. In 3 patients the Visual Analog Scale pain declined, whereas in the other 2 patients the Visual Analog Scale pain was unchanged over time.

CONCLUSIONS

In this pilot study, topical application of ISDN seems to be beneficial to improve symptoms for patients with cold type CRPS1, but further study is needed.

Inflammation, Metabolic Syndrome, Erectile Dysfunction, and Coronary Artery Disease: Common Links

OBJECTIVE

Erectile dysfunction (ED) may be the early clinical manifestation of a generalized vascular disease and carries an independent risk for cardiovascular events. Low-grade subclinical inflammation affects endothelial function and is involved in all stages of the atherosclerotic process. This review identifies potential pathophysiologic links among low-grade inflammation, ED, metabolic syndrome, and coronary artery disease (CAD) and presents the clinical implications in terms of ED diagnosis, assessment of patient risk, and therapy.

METHODS

A comprehensive evaluation was performed for available published data in full-length papers that were identified in MedLine up to July 2007.

RESULTS

Studies support an association between metabolic syndrome, ED, and increased inflammatory state. Increased circulating levels of inflammatory and endothelial-prothrombotic compounds are related to the presence and severity of ED. Specific inflammatory biomarkers and their combination appear to have the potential to aid ED diagnosis or exclusion. ED and CAD may confer a similar unfavorable impact on the inflammatory and prothrombotic state, whereas ED adds an incremental activation on top of CAD; these findings have important implications for cardiovascular risk. Lifestyle and risk factor modification, as well as pharmacologic therapy, are associated with anti-inflammatory effects.

CONCLUSIONS

Low-grade systemic inflammation could be an important element of the association between metabolic syndrome, ED, and CAD. Its individualized assessment may be a valuable tool for ED diagnosis, risk assessment, and rationalized therapeutic approach especially in patients with ED who have metabolic syndrome and carry an intermediate risk for future cardiovascular events.

Ageing-related corpora veno-occlusive dysfunction in the rat is ameliorated by pioglitazone

OBJECTIVE

To determine whether ageing-related changes in the penile corpora cavernosa, namely corporal veno-occlusive dysfunction (CVOD), loss of smooth muscle cells (SMCs), and excessive collagen deposition, can be ameliorated by the peroxisome proliferator-activated receptor gamma (PPARgamma) agonist pioglitazone, in a rat model of ageing as we have shown in a rat model of type 2 diabetes.

MATERIALS AND METHODS

Male Fischer 344 rats (16-18 months old) were fed chow containing 0%, 0.001% or 0.02% pioglitazone for 2 or 4.5 months, using 5 month old rats as 'young' controls. Functional changes were determined by dynamic-infusion cavernosometry (DIC). Histological changes were assessed by histochemistry and immunohistochemistry followed by quantitative image analysis and/or quantitative Western blot. Reactive oxygen species were estimated in blood.

RESULTS

Pioglitazone at both doses reduced the high DIC 'drop rate' present in the untreated aged groups to the level seen in the young rats. The papaverine response was increased to young control levels by short-term high-dose pioglitazone and the long-term low-dose treatment, but not by the short-term low-dose treatment. Pioglitazone at all doses and durations of treatment failed to reverse the decreased corporal SMC/collagen ratio and SMC content, oxidative stress, or the elevated contents of collagen, or transforming growth factor beta1, seen in the aged penis, but did reduce the collagen III/I ratio, and at a high dose increased apoptosis. Both treatments inhibited the Rho-kinase system, by increasing Src homology region 2-containing protein tyrosine phosphatase and reducing Vav. PPARgamma were detected in corporal SMCs.

CONCLUSIONS

Pioglitazone ameliorated ageing-related CVOD, possibly by a PPARgamma-mediated inhibition of Rho-kinase and not by a protective effect on the corporal smooth muscle.

Peripheral Mechanisms of Erectile Dysfunction in a Rat Model of Chronic Cocaine Use

OBJECTIVE

To evaluate the peripheral mechanisms of erectile dysfunction (ED) in a rat model of triple-binge cocaine administration.

METHODS

Adult male Sprague-Dawley rats (n=24) were divided into two groups: group 1, control rats receiving vehicle (saline); group 2, rats receiving binge cocaine injections. After completion of triple-binge cocaine or saline injections, both groups underwent an in vivo, neurogenic-mediated erectile response protocol to assess intracavernosal pressure (ICP). Penile endothelin-A and -B receptors (ET(A)R and ET(B)R), plasma levels of big endothelin-1 (big-ET-1), and endothelial nitric oxide synthase (eNOS) protein expression were assessed. To analyze nitric oxide (NO) production, we measured plasma nitrate-nitrite levels and quantitated myeloperoxidase (MPO) activity in cavernosal tissues to determine reactive oxygen species generation. Endothelium-dependent and -independent relaxation responses were evaluated in vitro. Data were analyzed with Student t test.

RESULTS

Triple-binge cocaine administration caused significantly decreased erectile responses as measured by ICP in vivo. Plasma big-ET-1 levels were significantly increased in the triple-binge cocaine treatment group compared with control animals. In the penis, triple-binge cocaine administration significantly increased ET(A)R expression compared with saline controls, while ET(B)R expression was not altered. Cocaine-treated rats had significantly decreased eNOS expression and NO production. The activity of tissue MPO was significantly increased in the cocaine group compared with control rats. Organ bath studies demonstrated that triple-binge cocaine resulted in a 64% reduction in maximal relaxation compared with the control group.

CONCLUSION

This study demonstrates that triple-binge cocaine administration significantly reduces erectile function in rats. The pathophysiologic mechanisms that are likely involved include increased plasma big-ET-1 levels, increased penile ET(A)R expression, increased penile MPO activity, and reduced penile eNOS expression.

Circulating Monocyte Oxidative Activity is Increased in Patients With Type 2 Diabetes and Erectile Dysfunction

PURPOSE

We investigated the relationship between oxidative stress and diabetic erectile dysfunction.

MATERIALS AND METHODS

A total of 23 patients with a mean +/- SD age of 56.7 +/- 5.6 years, a history of type 2 diabetes for 10.0 +/- 8.3 years and erectile dysfunction, as tested by the International Index of Erectile Function questionnaire, but without vascular and neurological complications, and 15 age matched patients with diabetes without erectile dysfunction were recruited. Circulating monocyte oxidative activity by cytofluorometry, and endothelin-1, intercellular adhesion molecule-1, plasminogen activator inhibitor-1 by enzyme linked immunosorbent assay were evaluated in all patients in the study.

RESULTS

Monocyte free radical production, and total and low density lipoprotein cholesterol were higher in patients with than in those without erectile dysfunction (p <0.03, <0.02 and <0.05, respectively). In all patients the International Index of Erectile Function score inversely correlated with low density lipoprotein (p <0.05), while in patients with erectile dysfunction it negatively correlated with age (p <0.03), body mass index (p <0.02), endothelin-1 (p <0.02) and intercellular adhesion molecule-1 (p <0.05). Endothelin-1, intercellular adhesion molecule-1 and plasminogen activator inhibitor-1 were not different in patients with diabetes with and without erectile dysfunction.

CONCLUSIONS

In men with type 2 diabetes who have erectile dysfunction but are asymptomatic for cardiovascular disease oxidative activation of monocytes is increased and it is related to other risk factors of endothelial dysfunction.

Valsartan treatment reverses erectile dysfunction in diabetic rats

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

Increased endothelin-1 and diminished nitric oxide levels in blister fluids of patients with intermediate cold type complex regional pain syndrome type 1

Background

In complex regional pain syndrome type 1 (CRPS1) pro-inflammatory mediators and vascular changes play an important role in the sustained development and outcome of the disease. The aim of this study was to determine the involvement of vasoactive substances endothelin-1 (ET-1) and nitric oxide (NO) during early chronic CRPS1.

Methods

Included were 29 patients with CRPS 1 who were diagnosed during the acute stage of their disease and observed during follow-up visits. Disease activity and impairment were determined and artificial suction blisters were made on the CRPS1 and the contralateral extremities for measurements of IL-6, TNF-α, ET-1 and nitrate/nitrite (NOx).

Results

The levels of IL-6, TNF-α and ET-1 in blister fluid in the CRPS1 extremity versus the contralateral extremity were significantly increased and correlated with each other, whereas NOx levels were decreased.

Conclusion

The NOx/ET-1 ratio appears to be disturbed in the intermediate stage of CRPS, resulting in vasoconstriction and consequently in a diminished tissue blood distribution.