Lower urinary tract symptoms and erectile dysfunction: epidemiology and treatment in the aging man

Effects of Omega-3 Fatty Acids on Erectile Dysfunction in a Rat Model of Atherosclerosis-induced Chronic Pelvic Ischemia

The aim of this study was to investigate whether the omega-3 fatty acids help to improve erectile function in an atherosclerosis-induced erectile dysfunction rat model. A total of 20 male Sprague-Dawley rats at age 8 weeks were divided into three groups: Control group (n = 6, untreated sham operated rats), Pathologic group (n = 7, untreated rats with chronic pelvic ischemia [CPI]), and Treatment group (n = 7, CPI rats treated with omega-3 fatty acids). For the in vivo study, electrical stimulation of the cavernosal nerve was performed and erectile function was measured in all groups. Immunohistochemical antibody staining was performed for transforming growth factor beta-1 (TGF-β1), endothelial nitric oxide synthase (eNOS), and hypoxia inducible factor 1-alpha (HIF-1α). In vivo measurement of erectile function in the Pathologic group showed significantly lower values than those in the Control group, whereas the Treatment group showed significantly improved values in comparison with those in the Pathologic group. The results of western blot analysis revealed that systemically administered omega-3 fatty acids ameliorated the cavernosal molecular environment. Our study suggests that omega-3 fatty acids improve intracavernosal pressure and have a beneficial role against pathophysiological consequences such as fibrosis or hypoxic damage on a CPI rat model, which represents a structural erectile dysfunction model.

[Genetic aspects of erectile dysfunction]

BACKGROUND

Erectile dysfunction (ED) is a common disorder in man that influences the quality of life of the patient and his partner. Known risk factors for ED comprise diabetes, coronary artery disease, hypertension but also lifestyle modifications such as smoking, diminished physical activity as well as obesity. In this manuscript the current scientific literature about genetics and erectile dysfunction is reviewed.

MATERIALS AND METHODS

A literature search using the databank PubMed covering the topics genetics and erectile dysfunction was performed and relevant papers selected for presentation.

RESULTS

Several aspects of genetics and ED are described in the current literature. Association studies of candidate polymorphisms and ED risk in comparison to healthy controls is a major area of research. Another topic is the genome-wide search for candidate polymorphisms with erectile dysfunction. The paper closes with the presentation of the pharmacogenomic analysis of treatment response to phosphodiesterase-5 inhibitors.

DISCUSSION

The heterogeneous results of genetic association studies are possibly due to small sample sizes of the study population and/or due to ethnic differences of the analyzed populations. This underlines the need for validation of this data in larger prospective multinational multicenter studies.

Prevalence and factors associated with uncomplicated storage and voiding lower urinary tract symptoms in community-dwelling Australian men

PURPOSE

To determine the prevalence of, and associated risk factors for, voiding and storage lower urinary tract symptoms (LUTS) in a population-based sample of Australian men.

METHODS

Data were collected from 1,103 men randomly selected, community-dwelling men, as part of the Florey Adelaide Male Ageing Study, after exclusion of men with prostate or bladder cancer or prior surgery to either organ. The presence of LUTS was assessed using the International Prostate Symptom Score. Urine flow was measured via flow meter. Demographic, clinical, and bio-psychosocial data were collected by questionnaire.

RESULTS

The prevalence of total, storage, and voiding LUTS was 18.1, 28.0 and 12.6%, respectively. The most common storage symptoms were frequency (12.3%), nocturia (9.9%) and urgency (8.1%), and voiding symptoms were weak stream (8.5%), intermittency (5.4%), incomplete emptying (5.1%) and straining (2.4%). There were linear associations between storage LUTS and increased abdominal fat mass, plasma glucose and low HDL cholesterol (components of the metabolic syndrome), obstructive sleep apnoea (OSA) risk, and retirement. Voiding symptoms were associated with a previous diagnosis of benign prostatic enlargement (BPH), mean peak urine flow, total energy intake, elevated risk of OSA, erectile dysfunction, physician-diagnosed thyroid dysfunction and higher household income.

CONCLUSIONS

The close association of storage LUTS with the metabolic syndrome, and of both storage and voiding LUTS with OSA, suggest that these conditions should be considered in men presenting with LUTS.

Emerging gene and stem cell therapies for the treatment of erectile dysfunction

Erectile dysfunction is a prevalent condition that leads to significant morbidity and distress, not just for affected men but also for their partners. Very few currently available treatments ameliorate the underlying causes of the disorder and 'cure' the disease state. Much recent effort has been focused on the development of gene and cell-based approaches to rectify the molecular and tissue defects responsible for ED. Gene therapy has been investigated in animal models as a means to restore normal function to the penis; at this time, however, only one human trial has been published in the peer-reviewed literature. Recent gene therapy studies have focused on the modulation of enzymes associated with the NOS/cGMP pathway, and supplementation of trophic factors, peptides and potassium channels. Stem cell therapy has been a topic of interest in more recent years but there are currently very few published reports in animal models and none in human men. Although stem cell therapy offers the potential for restoration of functional tissues, legitimate concerns remain regarding the long-term fate of stem cells. The long-term safety of both gene and stem cell therapy must be thoroughly investigated before large-scale human studies can be considered.

Silodosin: an orally active selective α1-adrenoceptor antagonist for benign prostatic hyperplasia

α1-adrenoceptor antagonists play a central role in the treatment of uncomplicated symptomatic benign prostatic hyperplasia, frequently in combination with the 5-α-reductase inhibitors such as finasteride and dutasteride. Clinically useful examples include alfuzosin, doxazosin, tamsulosin and terazosin. These can be subdivided into nonselective (doxazosin and terazosin) and uroselective (alfuzosin and tamsulosin) agents. In general, these agents appear to be equieffective. However, they can be distinguished on the basis of their adverse event profiles. Such adverse events include those due to their vasodilatory effects (dizziness, orthostatic hypotension and rhinitis), genitourinary effects (ejaculatory dysfunction) and nonspecific effects (e.g., asthenia, malaise and gastrointestinal upset). A new α1A-adrenoceptor antagonist, silodosin, has recently been approved. In most ways, it is similar to tamsulosin in its pharmacodynamic effects in vitro and in vivo (in both animals and humans). Limited clinical trial data have shown silodosin to significantly improve lower urinary tract symptoms associated with benign prostatic hyperplasia and quality of life, with effects sustainable for at least 1 year. Its adverse-event profile reflects that seen with other uroselective α-adrenoceptor antagonists with the exception of a relatively high-incidence rate of ejaculatory dysfunction (22 vs 2% with tamsulosin and 28 vs 1% with placebo). This article reviews the preclinical and clinical data concerning silodosin and introduces the reader to this new drug for the treatment of benign prostatic hyperplasia.

NO netting, health and stress – Studying wellness from a net perspective

On the nature of wellness, stress, netting and the radical gas nitric oxide (NO). The multi-complex role of NO resulted in its discoverers receiving a Nobel award, its presence everywhere and volatility makes it a suitable candidate to be a main signal in an instantaneous communication network. Such network, with the capacity of tight physiological monitoring, enables assets distributions in the body. A model is presented suggesting that an inter-cellular communication network coordinates the various bodily functions. Radical gases like nitric oxide (NO) are signals in this net and its usability affects health and indicates wellness. From this netting point of view, stress is the sense of flow interruption or blockage of the information stream. Such flow interruption affects also physiological functions and can explain the association between stress and many ailments. It is suggested that netting is a prerequisite route of wellness, enabling bodily unconscious managerial decisions. This vital diffusive network is extremely labile and potentially could contain the interplay of consciousness and unconsciousness effected by activities such as yoga or guided imagery. Vast data from studies on NO signals, health and the relaxation/stress processes have already been accumulated. Integration of these data supports this novel look of an NO network as a coordinator. Interactions between stress and health are discussed in net perspective and include basic concepts of some integrative health approaches. Studying the nature of such communication network and of NO may suggest new ways to reduce stress and approach wellness.

Is the Current Practice Providing an Integrated Approach to the Management of LUTS and ED in Primary Care? An Audit and Literature Review

INTRODUCTION

Lower urinary tract symptoms (LUTS) and erectile dysfunction (ED) are highly prevalent in aging men. A common pathophysiology is hypothesized to explain causal link. However, prevalence of ED in patients with LUTS remains underdiagnosed, as we believe general practitioners (GPs) do not inquire about ED in men presenting with LUTS.

AIM

Our goal to find out if LUTS and ED were dealt with in an integrated fashion in primary care.

METHODS

One hundred consecutive patients with LUTS attending the prostate assessment clinic anonymously completed a locally developed, qualitatively validated questionnaire and sexual health inventory for men.

MAIN OUTCOME MEASURES

(i) Prevalence of concomitant ED in men presenting with LUTS; (ii) proportion of GPs enquiring about ED; (iii) patients with LUTS + ED who were offered treatment in primary care; and (iv) patients who sought treatment on review in secondary care.

RESULTS

The age of patients was 39-86 years. Fifty-four percent admitted to ED: 66% >/=60 years, and 28% </=60 years had ED. Mean international prostate symptom score in both LUTS +/- ED groups was 16. There was a direct correlation between severity of LUTS and ED. Only 13/54 (24%) admitted ED to their GP. Of the patients, 15.4% received treatment, but 90.9% untreated patients were interested in therapy. Seventy-one percent stated definite reasons for inability to discuss their ED. GPs inquired about ED in only 9.2%. Overall, 66.6% wanted their ED addressed.

CONCLUSIONS

Fifty-four percent of the patients with LUTS also admitted to ED. Patients with more severe LUTS had more severe ED. More than 75% of patients did not report coexistent ED. GPs inquired about ED in only <10% of patients and offered no therapy to more than 80%. Sixty-seven percent of LUTS patients were interested in receiving treatment for ED when offered. A more integrated approach is desired to address the prevalence of ED in patients presenting with LUTS in order to offer them a comprehensive management in primary care.

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.

Antisense and Short Hairpin RNA (shRNA) Constructs Targeting PIN (Protein Inhibitor of NOS) Ameliorate Aging-Related Erectile Dysfunction in the Rat

INTRODUCTION

Over-expression of penile neuronal nitric oxide synthase (PnNOS) from a plasmid ameliorates aging-related erectile dysfunction (ED), whereas over-expression of the protein inhibitor of NOS (PIN), that binds to nNOS, increases ED.

AIM

To improve this form of gene therapy for ED by comparing the electrical field response of short hairpin RNA (shRNA) for PIN with that of antisense PIN RNA.

MAIN OUTCOME MEASURE

Both shRNA and antisense RNA gene therapy vectors increased intracavernosal pressure in aged rats.

METHODS

PIN small interfering RNA (siRNA), and plasmid constructs for cytomegalovirus promoter plasmid vector (pCMV-PIN), pCMV-PIN antisense RNA, pSilencer2.1-U6-PIN-shRNA; and pSilencer2.1-U6-randomer-shRNA were prepared and validated by transfection into HEK293 cells, determining the effects on PIN expression by Western blot. Plasmid constructs were then injected, followed by electroporation, into the penile corpora cavernosa of aged (20-month-old) Fisher 344 rats and, 1 month later, the erectile response was measured by intracavernosal pressure increase following electrical field stimulation (EFS) of the cavernosal nerve. PIN was estimated in penile tissue by Western blot and real-time reverse transcriptase-polymerase chain reaction. Cyclic guanosine monophosphate (cGMP) measurements were conducted by competitive enzyme immunoassay (EIA). Immunohistofluorescence detected PIN in corporal tissue sections.

RESULTS

In cell culture, PIN siRNA and plasmid-expressed pU6-PIN-shRNA effectively reduced PIN expression from pCMV-PIN. pSilencer2.1-U6-PIN-shRNA corrected the impaired erectile response to EFS in aged rats and raised it above the value for young rats, more efficiently than pCMV-PIN antisense RNA. PIN mRNA expression in the penis was decreased by >70% by the shRNA but remained unaffected by the antisense RNA, whereas PIN protein expression was reduced in both cases, particularly in the dorsal nerve. PIN antisense increased cGMP concentration in treated tissue by twofold.

CONCLUSION

pSilencer2.1-U6-PIN-shRNA gene therapy was more effective than the antisense PIN mRNA in ameliorating ED in the aged rat, thereby suggesting that PIN is indeed a physiological inhibitor of nNOS and nitrergic neurotransmission in the penis.

Long-Term Continuous Treatment with Sildenafil Ameliorates Aging-Related Erectile Dysfunction and the Underlying Corporal Fibrosis in the Rat1

Aging-related erectile dysfunction is characterized by a loss of smooth muscle cells (SMCs) and fibrosis in the corpora cavernosa, and functionally by corporal veno-occlusive dysfunction (CVOD). Phosphodiesterase 5 (PDE5A) inhibitors, in part via upregulating inducible nitric oxide synthase (NOS2A), have antifibrotic properties in penile tissues. We aimed to determine whether in the aged rat the chronic long-term treatment with sildenafil ameliorates corporal SMC loss and fibrosis, stimulates NOS2A induction, and corrects the associated CVOD. Aged male rats (20 mo old) received sildenafil in their drinking water (20 mg/kg per day) or plain water for 45 days, and untreated young rats (5 mo old) served as controls (n = 8 per group). CVOD was assessed by dynamic infusion cavernosometry (DIC). Collagen:SMC (Masson trichrome) and collagen III:I (picrosirius red) ratios, SMC content (alpha-smooth muscle actin [ACTA2]), cell proliferation (proliferating nuclear antigen [PCNA]), apoptotic death (TUNEL), and NOS2A induction were measured by histochemistry and immunohistochemistry followed by quantitative image analysis. Collagen content was determined by hydroxyproline assay, and transforming growth factor beta-1 (TGFB1); xanthine oxidoreductase (XDH); ACTA2; NOS2A; and the Rho kinase inhibitor protein tyrosine phosphatase, nonreceptor type 11 (PTPN11), and activator, VAV, were measured by quantitative Western blot. In the aged rats treated with sildenafil, the erectile response by DIC was normalized, and the corporal SMC:collagen ratio and SMC number were increased. In addition, sildenafil reduced the corporal collagen content without affecting the collagen III:I ratio, increased the PCNA:apoptosis ratio, and stimulated NOS2A induction, although there was no effect on XDH, TGFB1, PTPN11, or VAV levels. These data show that long-term PDE5A treatment corrected CVOD in the aged rat and partially reversed the aging-related fibrosis and loss of SMC in the corpora cavernosa without affecting TGFB1 or PTPN11 levels, which are markers of oxidative stress. It may be speculated that similar effects may be achieved with this paradigm in men.

Management of sildenafil treatment failures

PURPOSE OF REVIEW

Although oral type 5 phosphodiesterase inhibitors are considered as first-line therapy for the majority of causes of erectile dysfunction, because of their high efficacy, ease of use, and acceptable safety profile, there are some who fail to respond, mainly because of end-organ failure. This communication reviews the management of sildenafil failures in light of recent advances.

RECENT FINDINGS

Sildenafil failures can be attributed to either lack of efficacy or side effects; issues may involve the physician, patient, and his partner. Physicians may contribute to sildenafil failure and discontinuation because of inadequate instructions, lack of adequate follow-up, suboptimal dosing, lack of adequate trial, and insufficient clarification about safety issues. Studies have demonstrated that progression of endothelial dysfunction and diminished cavernosal smooth-muscle content are recognized organic factors which cause end-organ dysfunction and ultimately treatment failure.

SUMMARY

Proper counseling, medication optimization, and modifying associated risk factors can provide success in men who had initially failed sildenafil therapy for erectile dysfunction. Other treatment modalities that may be considered when sildenafil failure occurs include vacuum devices, intraurethral, and intracavernosal administration of vasoactive drugs alone or combined with sildenafil. Penile prosthesis implantation is considered as a last resort, if all first-line and second-line therapies fail.