Alterations of M 2,3 -Muscarinic Receptor Protein and mRNA Expression in the Bladder of the Fructose Fed Obese Rat

Association between the American Heart Association's new "Life Essentials 8" metrics and urgency urinary incontinence and nocturia

BACKGROUND

Despite its widespread adoption in cardiovascular research, the application of LE8 in other health conditions, particularly urgency urinary incontinence (UUI) and nocturia, has not been thoroughly investigated. Our study used the Life's Essential 8 (LE8) score to evaluate the relationship between cardiovascular health (CVH) and urge urinary incontinence and nocturia in adults.

METHODS

This analysis utilized data from the National Health and Nutrition Examination Survey (NHANES) spanning 2011-2018. We used the LE8 score as the independent variable, and UUI and nocturia as the dependent variables. Multivariable logistic regression was conducted to explore the association between the LE8 score and the occurrence of UUI and nocturia.

RESULTS

The study included 12,566 adults aged 20 and older. After adjusting for potential confounders, a higher LE8 score was inversely associated with the risk of UUI (OR = 0.38; 95% CI: 0.27-0.52, p < 0.0001) and nocturia (OR = 0.53; 95% CI: 0.44-0.65, p < 0.0001).

CONCLUSION

This cross-sectional study revealed an inverse relationship between the LE8 score and the likelihood of both UUI and nocturia.

Pathophysiology of Overactive Bladder and Pharmacologic Treatments Including β3-Adrenoceptor Agonists -Basic Research Perspectives

Overactive bladder (OAB) is a symptom-based syndrome defined by urinary urgency, frequency, and nocturia with or without urge incontinence. The causative pathology is diverse; including bladder outlet obstruction (BOO), bladder ischemia, aging, metabolic syndrome, psychological stress, affective disorder, urinary microbiome, localized and systemic inflammatory responses, etc. Several hypotheses have been suggested as mechanisms of OAB generation; among them, neurogenic, myogenic, and urothelial mechanisms are well-known hypotheses. Also, a series of local signals called autonomous myogenic contraction, micromotion, or afferent noises, which can occur during bladder filling, may be induced by the leak of acetylcholine (ACh) or urothelial release of adenosine triphosphate (ATP). They can be transmitted to the central nervous system through afferent fibers to trigger coordinated urgency-related detrusor contractions. Antimuscarinics, commonly known to induce smooth muscle relaxation by competitive blockage of muscarinic receptors in the parasympathetic postganglionic nerve, have a minimal effect on detrusor contraction within therapeutic doses. In fact, they have a predominant role in preventing signals in the afferent nerve transmission process. β3-adrenergic receptor (AR) agonists inhibit afferent signals by predominant inhibition of mechanosensitive Aδ-fibers in the normal bladder. However, in pathologic conditions such as spinal cord injury, it seems to inhibit capsaicin-sensitive C-fibers. Particularly, mirabegron, a β3-agonist, prevents ACh release in the BOO-induced detrusor overactivity model by parasympathetic prejunctional mechanisms. A recent study also revealed that vibegron may have 2 mechanisms of action: inhibition of ACh from cholinergic efferent nerves in the detrusor and afferent inhibition via urothelial β3-AR.

Correlation Between Insulin Resistance and Urinary Incontinence in Female Patients with Type 2 Diabetes Mellitus

INTRODUCTION AND HYPOTHESIS

Patients with type 2 diabetes mellitus (T2DM) are at a high risk of developing urinary incontinence; however, its pathogenesis is unclear. The purpose of this study is to explore the relationship between insulin resistance and urinary incontinence and its severity in female patients with T2DM.

METHODS

A total of 366 women with T2DM aged ≥18 years were enrolled in this study. Insulin resistance was evaluated by the homeostasis model insulin resistance (HOMA-IR) index and urinary incontinence was assessed by the International Consultation on Incontinence Questionnaire Short Form (ICIQ-SF). All subjects were divided into four groups according to HOMA-IR quartiles. Logistic regression analysis was performed to investigate the relationship between insulin resistance and urinary incontinence and its severity.

RESULTS

Among the 366 patients, 186 (50.8%) had urinary incontinence. The prevalence of urinary incontinence increased significantly with HOMA-IR quartiles (p < 0.001). Adjusted logistic regression analysis showed that compared with HOMA-IR ≤ 1.76, 2.81 ≤ HOMA-IR ≤ 4.27 was associated with a significantly increased risk of moderate incontinence (OR = 2.197, 95% CI 1.031-4.683, p = 0.041), and HOMA-IR ≥ 4.28 was associated with a significantly increased risk of severe incontinence (OR = 5.699, 95% CI 1.685-19.276, p = 0.005). Binary logistic regression analysis showed that HOMA-IR was the independent risk factor for urinary incontinence (p < 0.001).

CONCLUSIONS

Higher levels of insulin resistance are associated with urinary incontinence and its severity in female patients with type 2 diabetes mellitus.

Association between lower urinary tract symptoms and polycystic ovary syndrome

OBJECTIVE

The aim of this study was to analyze the association between lower urinary tract symptoms and polycystic ovary syndrome.

METHODS

A total of 180 women were enrolled in this prospective study. Demographic data, body mass index, waist circumference, modified Ferriman-Gallwey scores, biochemical parameters, ultrasonographic findings, and maximum urinary flow rate (Q max) were analyzed. In addition, the Beck Depression Inventory, Beck Anxiety Inventory, and Bristol Female Lower Urinary Tract Symptom Scored Form questionnaires were evaluated for each subject.

RESULTS

The mean age of patients was calculated as 23.78±3.04 years, which was similar for both groups (p=0.340). Body mass index, waist circumference, Beck Depression Inventory, Beck Anxiety Inventory, Bristol Female Lower Urinary Tract Symptom Scored Form, and modified Ferriman-Gallwey scores were significantly higher in group 2 (p<<0.001). Hyperandrogenism, lipid profile, and glucose metabolism disorders were more frequent in group 2 (p<<0.05). Bladder capacity (Q max), bladder wall thickness, and post-void residual volume values were similar in both groups (p>>0.05).

CONCLUSION

In our study, a close relationship was observed between polycystic ovary syndrome and lower urinary tract symptoms. In this context, we think that a detailed urinary system evaluation of women with polycystic ovary syndrome is extremely important.

Effects of different diets used to induce obesity/metabolic syndrome on bladder function in rats

Preclinical and human studies on the relationship between obesity/metabolic syndrome (MetS) and lower urinary tract dysfunction (LUTD) are inconsistent. We compared the temporal effects of feeding four different diets used to induce obesity/MetS, including 60% fructose, 2% cholesterol +10% lard, 30% fructose + 20% lard, or 32.5% lard diet, up to 42 wk, on metabolic parameters and bladder function in male Sprague-Dawley rats. Rats fed a 30% fructose + 20% lard or 32.5% lard diet consumed less food (grams), but only the 32.5% lard diet group took in more calories. Feeding rats a 60% fructose or 30% fructose + 20% lard diet led to glucose intolerance and increased blood pressure. Higher body weight and increased cholesterol levels were observed in the rats maintained on a 2% cholesterol +10% lard diet, whereas exposure to a 32.5% lard diet affected most of the above parameters. Voiding behavior measurement showed that voiding frequency and the total voided volume were lower in the experimental diet groups except for the 30% fructose + 20% lard group. The mean voided volume was lower in the 30% fructose + 20% lard and 32.5% lard groups compared with the control group. Cystometric analysis revealed a decreased bladder capacity, mean voided volume, intermicturition interval, and compliance in the 32.5% lard diet group. In conclusion, experimental diets including 60% fructose, 30% fructose + 20% lard, or 2% cholesterol + 10% lard diet differently affected physiological and metabolic parameters and bladder function to a limited extent, while exposure to a 32.5% lard diet had a greater impact.

Metabolic Syndrome and Overactive Bladder Syndrome May Share Common Pathophysiologies

Metabolic syndrome (MetS) is defined by a group of cardiovascular risk factors, including impaired glucose tolerance, central obesity, hypertension, and dyslipidemia. Overactive bladder (OAB) syndrome consists of symptoms such as urinary urgency, frequency, and nocturia with or without urge incontinence. The high prevalences of metabolic syndrome (MetS) and overactive bladder (OAB) worldwide affect quality of life and cause profound negative impacts on the social economy. Accumulated evidence suggests that MetS might contribute to the underlying mechanisms for developing OAB, and MetS-associated OAB could be a subtype of OAB. However, how could these two syndromes interact with each other? Based on results of animal studies and observations in epidemiological studies, we summarized the common pathophysiologies existing between MetS and OAB, including autonomic and peripheral neuropathies, chronic ischemia, proinflammatory status, dysregulation of nutrient-sensing pathways (e.g., insulin resistance at the bladder mucosa and excessive succinate intake), and the probable role of dysbiosis. Since the MetS-associated OAB is a subtype of OAB with distinctive pathophysiologies, the regular and non-specific medications, such as antimuscarinics, beta-3 agonist, and botulinum toxin injection, might lead to unsatisfying results. Understanding the pathophysiologies of MetS-associated OAB might benefit future studies exploring novel biomarkers for diagnosis and therapeutic targets on both MetS and OAB.

Tadalafil ameliorates bladder overactivity by restoring insulin-activated detrusor relaxation via the bladder mucosal IRS/PI3K/AKT/eNOS pathway in fructose-fed rats

The pathophysiologies of metabolic syndrome (MS) and overactive bladder (OAB) might overlap. Using fructose-fed rats (FFRs) as a rodent model of MS we investigated the effects of tadalafil (a phosphodiesterase type 5 inhibitor) on the dysregulated insulin signalling in the bladder mucosa and bladder overactivity. Micturition behaviour was evaluated. Concentration-response curves on detrusor relaxation to insulin stimulation were examined. Expression and phosphorylation of proteins in the insulin signalling pathway were evaluated by Western blotting. Levels of detrusor cGMP and urinary nitrite and nitrate (NOx) were measured. We observed FFRs exhibited metabolic traits of MS, bladder overactivity, and impaired insulin-activated detrusor relaxation in organ bath study. A high-fructose diet also impeded insulin signalling, reflected by overexpression of IRS1/pIRS1^Ser307 and pIRS2^Ser731 and downregulation of PI3K/pPI3K^Tyr508, AKT/pAKT^Ser473, and eNOS/peNOS^Ser1177 in the bladder mucosa, alongside decreased urinary NOx and detrusor cGMP levels. Tadalafil treatment restored the reduced level of mucosal peNOS, urinary NOx, and detrusor cGMP, improved the insulin-activated detrusor relaxation, and ameliorated bladder overactivity in FFRs. These results suggest tadalafil may ameliorate MS-associated bladder overactivity by restoring insulin-activated detrusor relaxation via molecular mechanisms that are associated with preservation of IR/IRS/PI3K/AKT/eNOS pathway in the bladder mucosa and cGMP production in the bladder detrusor.

Study on the pathophysiological mechanism responsible for lower urinary tract symptoms associated with prostate cancer using an animal model

OBJECTIVES

To investigate the pathophysiological mechanism leading to lower urinary tract symptoms in prostate cancer (PCa) by using an animal model.

METHODS

An orthotopic PCa model in mice was established by injection of human DU145 cells into the prostate gland lateral lobe of NOD.CB17-Prkdc^scid /NcrCrlBltw (NOD-SCID) mice. Cancer growth was quantified by a luciferase-based in vivo imaging system (IVIS) serially every 7 days. Comparisons were made for urodynamic parameters, bladder histology, and biological markers until the sixth week. Bladder wall structural changes were assessed by the bladder wall thickness and degree of fibrosis. Biomarker expressions in bladder tissue including muscarinic acetylcholine receptor 2 (M₂ ), transient receptor potential cation channel subfamily V member 4 (TRPV4), BCL2-associated X protein (Bax), and caspase3 were evaluated by immunohistochemical staining and immunofluorescence confocal laser scanning microscopy.

RESULTS

DU145 cell growth in the prostate was successfully monitored by a luciferase-based IVIS. after orthotopic injection. Using our injection technique, no anatomical obstruction of the bladder outlet and urethra was noted up to 6 weeks after injection. The presence of PCa induced changes in urinary bladder histology, biomarkers, and urodynamic parameters. Cystometry showed features of detrusor overactivity with increased voiding frequency and high-amplitude voiding contractions from the fourth week onward. Histological analyses 4 weeks after DU145 injection demonstrated detrusor thickening and bladder wall fibrosis. Immunohistochemistry showed increased expressions of bladder M₂ , TRPV4, Bax, and caspase3 in the PCa mice as early as in the first or second week.

CONCLUSIONS

PCa can induce bladder microenvironment changes involving neural receptors and biological mediators leading to histological and functional alterations even in the absence of overt anatomical obstruction.

Bladder Dysfunction in an Obese Zucker Rat: The Role of TRPA1 Channels, Oxidative Stress, and Hydrogen Sulfide

Purpose

This study investigates whether functionality and/or expression changes of transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential ankyrin 1 (TRPA1) channels, oxidative stress, and hydrogen sulfide (H₂S) are involved in the bladder dysfunction from an insulin-resistant obese Zucker rat (OZR).

Materials and Methods

Detrusor smooth muscle (DSM) samples from the OZR and their respective controls, a lean Zucker rat (LZR), were processed for immunohistochemistry for studying the expression of TRPA1 and TRPV1 and the H₂S synthase cystathionine beta-synthase (CBS) and cysthathionine-γ-lyase (CSE). Isometric force recordings to assess the effects of TRPA1 agonists and antagonists on DSM contractility and measurement of oxidative stress and H₂S production were also performed.

Results

Neuronal TRPA1 expression was increased in the OZR bladder. Electrical field stimulation- (EFS-) elicited contraction was reduced in the OZR bladder. In both LZR and OZR, TRPA1 activation failed to modify DSM basal tension but enhanced EFS contraction; this response is inhibited by the TRPA1 blockade. In the OZR bladder, reactive oxygen species, malondialdehyde, and protein carbonyl contents were increased and antioxidant enzyme activities (superoxide dismutase, catalase, GR, and GPx) were diminished. CSE expression and CSE-generated H₂S production were also reduced in the OZR. Both TRPV1 and CBS expressions were not changed in the OZR.

Conclusions

These results suggest that an increased expression and functionality of TRPA1, an augmented oxidative stress, and a downregulation of the CSE/H₂S pathway are involved in the impairment of nerve-evoked DSM contraction from the OZR.

Role of corticotropin-releasing factor on bladder function in rats with psychological stress

Stress-related peptide corticotropin-releasing factor (CRF) and CRF-related peptides are distributed in the peripheral viscera such as the bladder. We investigated the contribution of psychological stress (PS) and CRF on bladder function. Male rats received sham stress (SS) or PS using a communication box method for 120 min every day for 7 days. One group of rats received the intraperitoneal CRF-R1 antagonist antalarmin for 7 days during stress exposure. Mean voided volume per micturition was significantly lower in PS rats compared to SS rats, which was antagonized by antalarmin treatment. Increases in plasma and bladder CRF, and mRNA expressions of bladder CRF, CRF-R1, and M2/3 muscarinic receptors, were found in PS rats. CRF did not influence bladder contraction in itself; however, stress increased the response of muscarinic contraction of bladder strips. These changes were antagonized by antalarmin treatment. In conclusion, PS reinforces M3 receptor-mediated contractions via CRF-R1, resulting in bladder storage dysfunction.

Translational insights on developmental origins of metabolic syndrome: Focus on fructose consumption

Metabolic syndrome (MetS) is a highly prevalent complex trait despite recent advances in pathophysiology and pharmacological treatment. MetS can begin in early life by so-called the developmental origins of health and disease (DOHaD). The DOHaD concept offers a novel approach to prevent MetS through reprogramming. High fructose (HF) intake has been associated with increased risk of MetS. HF diet becomes one of the most commonly used animal model to induce MetS. This review discusses the maternal HF diet induced programming process and reprogramming strategy to prevent MetS of developmental origin, with an emphasis on: (1) an overview of metabolic effects of fructose consumption on MetS; (2) insight from maternal HF animal models on MetS-related phenotypes; (3) impact of HF consumption induces organ-specific transcriptome changes; and (4) application of reprogramming strategy to prevent maternal HF consumption-induced MetS. Research into the preventions and treatments of MetS that begin early in life will have a lifelong impact and profound savings in disease burden and financial costs.

Risk factors and factors affecting the severity of overactive bladder symptoms in Korean women who use public health centers

Objective

To investigate the prevalence, risk factors of overactive bladder (OAB) and the factors affecting the severity of OAB symptoms.

Methods

A total 822 interviews with women aged 18–80 years who visited public health centers were conducted between April 2014 and April 2015. The questionnaire was composed of 16 questions about urinary symptoms, 14 questions about self-treatment and the use of complementary and alternative medicine, and 21 questions about socio-demographic characteristics. The diagnostic criterion for OAB is a total OAB symptom score of 3 and more, with an urgency score of 2 or more. To know the risk factors and factors affecting the severity of OAB, the multivariate logistic regression analysis was performed.

Results

One hundred fifty-seven participants (19.3%) were diagnosed with OAB, of whom 10.7%, 8.1%, and 0.7% had mild, moderate, and severe OAB symptoms, respectively. In addition, the prevalence of OAB increased with age. Among all the participants, 39.1% had stress incontinence, among them 32.7% had OAB as well. The significant risk factors of OAB were identified as age, current smoking, hyperlipidemia, cardiovascular and renal disease, whereas, the factors affecting the severity of OAB were age, current smoking, and hyperlipidemia.

Conclusion

Those who have risk factors and factors affecting severity of OAB should be educated to increase OAB awareness and act of urinary health promotion.

Single onabotulinumtoxinA 200U dose improved clinical symptoms but not urothelial dysfunction in neurogenic detrusor overactivity due to spinal cord injury

OBJECTIVE

To evaluate the changes in urothelial dysfunction protein expressions in bladder after onabotulinumtoxin injection and correlate that with clinical outcomes in spinal cord injury (SCI) patients.

METHODS

Twenty-six patients with neurogenic detrusor overactivity (NDO) and urinary incontinence due to suprasacral SCI were treated with onabotulinumtoxinA 200U detrusor injection. Urodynamic studies and bladder biopsies were obtained at baseline, 3, and 6 months after treatment. Biopsy tissues were investigated for E-cadherin, zonula occludens-1 (ZO-1), mast cell activity, and urothelial cell apoptosis, sensory protein expression including purinergic receptor P2X3, endothelial NOS, inducible NOS, β3-adrenoceptors, and muscarinic receptors M2 and M3. Differences in functional protein expression between controls and SCI patients and between successful and failed treatment groups were analyzed.

RESULTS

SCI patients had significantly lower E-cadherin, higher mast cell activity, increased apoptosis, decreased M3 and eNOS expressions than the controls at baseline. Of the 26 patients, 17 (65%) showed improvement in bladder capacity by >50% at 3 months; however, improvement declined by 6 months after treatment. The urothelial expression of E-cadherin and ZO-1 increased at 3 months but had declined at 6 months. The urothelial sensory protein expression did not change significantly after treatment. M3 receptor density was significantly decreased in SCI patients at baseline and patients with treatment success 3 months after injection (p = 0.01).

CONCLUSION

A single injection of onabotulinumtoxinA 200U improved clinical symptoms but did not significantly alter urothelial sensory protein expression. The results imply that a single 200U onabotulinumtoxinA dose might not be adequate for urothelial dysfunction in NDO. IRB: TCGH 098-53.

Improvement in bladder dysfunction after bladder transplantation of amniotic fluid stem cells in diabetic rats

To examine the effects of human amniotic fluid stem cells (hAFSCs) transplantation on bladder function and molecular changes in diabetic rats, 60 female Sprague-Dawley rats were used for study. Three groups were assigned including sham control rats, streptozotocin (STZ, 60 mg/kg)-induced diabetic rats and STZ-induced diabetic rats plus bladder hAFSCs transplantation. Compared to controls, diabetic rats had decreased body weight but increased bladder weight. Cystometries showed non-voiding contraction, residual volume, voided volume and intercontraction interval increased significantly in diabetic rats at week 4 and 12 after DM induction, but improved after hAFSCs transplantation. The immunoreactivities and mRNAs of nerve growth factor (NGF) decreased significantly in diabetic bladder at week 4 and 12 after DM induction, but recovered after hAFSCs transplantation. The immunoreactivities and mRNAs of M2 and M3 muscarinic receptor increased significantly in diabetic bladder at week 4 after DM induction but recovered after hAFSCs transplantation. The immunoreactivity of 8-hydroxy-20-deoxyguanosine increased significantly in diabetic bladder at week 4 and 12 after DM induction but reduced after hAFSCs transplantation. The present study showed bladder dysfunction in STZ-induced diabetic rats could be improved by hAFSCs transplantation into bladder, which may be related to the recovery of bladder NGF and muscarinic receptors.

Effect of a Carbohydrate-Rich Diet on Rat Detrusor Smooth Muscle Contractility: An Experimental Study

OBJECTIVES

We aimed to investigate the effect of a carbohydrate-rich diet on detrusor contractility in rats.

MATERIALS AND METHODS

Sprague-Dawley rats were randomized into two groups. The control group received regular food and water. The study group received carbohydrate-rich diet for six weeks. The rats' detrusor muscle was isolated for pharmacological and histopathological examinations.

RESULTS

In the control and study groups, mean body weights were 431.5 ± 27.6 g and 528.0 ± 36.2 g, respectively (p < 0.001). Electrical stimulation of the detrusor strips of the control group resulted in gradual contraction. A decreased contractile response was shown in the study group. Acetylcholine in 10-7-10-3 molar concentration produced a decreased contractile response in the study group, compared to the control group (p < 0.01). The study group showed marked subepithelial and intermuscular fibrosis in the bladder.

CONCLUSION

Carbohydrate-rich diet causes marked subepithelial and extracellular fibrosis and changes in contractility in the detrusor within a six-week period. Changes have higher costs in therapeutic choices and correction of these changes remains difficult. Putting an end to carbohydrate-rich diet would seem to be more cost-effective than dealing with the effects of consuming it in high proportions which should be the national policy worldwide.

Changes of Bladder M1,3 Muscarinic Receptor Expression in Rats Fed with Short-Term/Long-Term High-Fat Diets

OBJECTIVES

To investigate the effect of high-fat diet (HFD) on bladder M_1,3 muscarinic receptor expression and contractile function in the rat.

METHODS

Eight-week-old male rats were divided into two groups including one with HFD for 8 weeks (short-term) and the other for 24 weeks (long-term). Each group was compared to age-matched rats fed with normal chow as controls. The body weight, food intake amount and blood biochemistry were monitored. Bladder muscle contractile responses to acetylcholine (0.1-10 μM), bethanechol (10 μM) and KCl (50 mM) were studied in an organ bath set-up. Bladder M₁ and M₃ muscarinic receptor protein expressions were measured by Western blotting analysis.

RESULTS

Increase in body weight as well as blood triglyceride, cholesterol and sugar levels compared to controls were noted in both 8- and 24-week HFD rats. Eating appetite change with increased food and water intakes was noted in the HFD rats. Significantly decreased bladder contractile responses to acetylcholine and bethanechol were shown in both HFD groups. On the other hand, decreased bladder contractile response to KCl was demonstrated in the 24-week group but not the 8-week group. The expressions of bladder M₁ and M₃ muscarinic receptor proteins were significantly and progressively decreased by HFD feeding from 8 to 24 weeks.

CONCLUSIONS

High-fat diet induces obesity and polyphagia in rats. Short-term and long-term HFD feeding decrease rat bladder M₁ and M₃ receptor expressions as well as contractile responses to the agonistic stimulation. In addition, bladder muscle dysfunction develops after long-term HFD feeding.

Sulforaphane Improves Ischemia-Induced Detrusor Overactivity by Downregulating the Enhancement of Associated Endoplasmic Reticulum Stress, Autophagy, and Apoptosis in Rat Bladder

Atherosclerosis-associated pelvic ischemia has been reported to be a risk factor for bladder dysfunction and subsequent lower urinary tract symptoms (LUTS) in the elderly population. However, the molecular mechanisms of this association remain unclear. We hypothesized that stress-induced cellular responses might play a role in the pathogenesis of ischemia-induced bladder dysfunction. In the present study, the animal model of bladder ischemia was induced by bilateral partial arterial occlusion (BPAO) in rats. We found that BPAO significantly induced the presence of detrusor overactivity (DO) and upregulated the expression of several molecular reactions, including biomarkers in endoplasmic reticulum stress (78 kDa glucose-regulated protein, GRP78 and C/EBP-homologous protein, CHOP), autophagy (Beclin-1, p62 and LC3 II) and apoptosis (caspase 3). BPAO also disturbed the Kelch-like ECH-associated protein 1–nuclear factor erythroid-2-related factor 2 (Keap1–Nrf2) pathways. These responses might collectively alter muscarinic and purinergic signaling and contribute to the presence of DO in the ischemic bladder. Therapeutically, treatment with neither a muscarinic nor purinergic receptor antagonist restored bladder function. Interestingly, sulforaphane effectively attenuated ischemia-enhanced endoplasmic reticulum stress, autophagy and apoptosis in the bladder, subsequently ameliorated ischemia-induced bladder dysfunction and might emerge as a novel strategy to protect the bladder against ischemia-induced oxidative damage.

Long-term treatment with the beta-3 adrenoceptor agonist, mirabegron ameliorates detrusor overactivity and restores cyclic adenosine monophosphate (cAMP) levels in obese mice

AIMS

To evaluate the effects of the beta-3 adrenoceptor agonist, mirabegron in a mouse model of detrusor overactivity induced by obesity.

METHODS

C57BL/6 male mice were fed with standard chow or high-fat diet for 12 weeks. Lean and obese mice were treated orally with mirabegron (10 mg/kg/day) from the last 2 weeks of diet. Cystometric evaluations, functional assays, protein expression for phosphodiesterase type 4 (PDE4), and cyclic adenosine monophosphate (cAMP) measurement were carried out.

RESULTS

In obese mice the body weight, epididymal fat mass, fasting glucose, and low-density lipoprotein (LDL) levels were higher (P < 0.001) than in the lean mice. A reduction of 34% and 54% and an increase of 35% in the epididimal fat, LDL, and HDL levels (P < 0.05), respectively, were observed in the obese group treated with mirabegron, whereas no changes were seen in the lipid profile from lean mice. Obese group showed irregular micturition pattern, characterized by significant increases in frequency and non-void contractions. Carbachol, potassium chloride, and electrical-field stimulation induced detrusor smooth muscle (DSM) contractions, which were greater in bladders from obese mice than from lean mice. Two-week treatment with mirabegron restored all the contractile response alterations in the DSM. Basal intracellular levels of cAMP were reduced (68%), whereas PDE4 protein expression was increased (54%) in bladder from obese mice. Mirabegron restored the cAMP levels in obese bladder, without changing the PDE4 expression.

CONCLUSION

Mirabegron was able to completely restore the urinary alterations seen in the bladder from obese mice.

Maternal Fructose Exposure Programs Metabolic Syndrome-Associated Bladder Overactivity in Young Adult Offspring

Maternal fructose exposure (MFE) programs the development of metabolic syndrome (MetS) in young adult offspring. Epidemiological data indicate that MetS may increase the risks of overactive bladder (OAB) symptoms. However, it remains unknown whether MFE programs MetS-associated bladder dysfunction in adult offspring. Using Sprague-Dawley rats, we investigated the effects of MFE during pregnancy and lactation on developmental programming of MetS-associated bladder dysfunction. In addition, next generation sequencing technology was used to identify potential transcripts involved in the programmed bladder dysfunction in adult male offspring to MFE. We found that MFE programmed the MetS-associated OAB symptoms (i.e., an increase in micturition frequency and a shortened mean inter-contractile interval) in young adult male offspring, alongside significant alterations in bladder transcripts, including Chrm2, Chrm3, P2rx1, Trpv4, and Vipr2 gene expression. At protein level, the expressions of M₂-, M₃-muscarinic and P2X₁ receptor proteins were upregulated in the MFE bladder. Functionally, the carbachol-induced detrusor contractility was reduced in the MFE offspring. These data suggest that alterations in the bladder transcripts and impairment of the bladder cholinergic pathways may underlie the pathophysiology of programmed bladder dysfunction in adult offspring to MFE.

Impaired Excitatory Neurotransmission in the Urinary Bladder from the Obese Zucker Rat: Role of Cannabinoid Receptors

Metabolic syndrome (MS) is a known risk factor for lower urinary tract symptoms. This study investigates whether functional and expression changes of cannabinoid CB₁ and CB₂ receptors are involved in the bladder dysfunction in an obese rat model with insulin resistance. Bladder samples from obese Zucker rat (OZR) and their respective controls lean Zucker rat (LZR) were processed for immunohistochemistry and western blot for studying the cannabinoid receptors expression. Detrusor smooth muscle (DSM) strips from LZR and OZR were also mounted in myographs for isometric force recordings. Neuronal and smooth muscle CB₁ and CB₂ receptor expression and the nerve fiber density was diminished in the OZR bladder. Electrical field stimulation (EFS) and acetylcholine (ACh) induced frequency- and concentration-dependent contractions of LZR and OZR DSM. ACh contractile responses were similar in LZR and OZR. EFS-elicited contractions, however, were reduced in OZR bladder. Cannabinoid receptor agonists and antagonists failed to modify the DSM basal tension in LZR and OZR In LZR bladder, EFS responses were inhibited by ACEA and SER-601, CB₁ and CB₂ receptor agonists, respectively, these effects being reversed by ACEA plus the CB₁ antagonist, AM-251 or SER-601 plus the CB₂ antagonist, AM-630. In OZR bladder, the inhibitory action of ACEA on nerve-evoked contractions was diminished, whereas that SER-601 did not change EFS responses. These results suggest that a diminished function and expression of neuronal cannabinoid CB₁ and CB₂ receptors, as well as a lower nerve fiber density is involved in the impaired excitatory neurotransmission of the urinary bladder from the OZR.

Ba-Wei-Die-Huang-Wan (Hachimi-jio-gan) can ameliorate cyclophosphamide-induced ongoing bladder overactivity and acidic adenosine triphosphate solution-induced hyperactivity on rats prestimulated bladder

ETHNOPHARMACOLOGICAL RELEVANCE

Ba-Wei-Die-Huang-Wan (BWDHW) is the traditional Chinese medicine formula containing eight ingredients, namely Rehmannia glutinosa (Gaetn.) DC., root, steamed & dried; Cornus officinalis Siebold & Zucc., fructus, dried; Dioscorea oppositifolia L., root, dried; Alisma plantago-aquatica, subsp. orientale (Sam.) Sam., tuber, dried; Poria cocos (Fr.) Wolf., sclerotium, dried; Paeonia×suffruticosa Andrews, bark, dried; Cinnamomum cassia (Nees & T.Nees) J. Presl, bark, dried; Aconitum carmichaeli Debeaux, lateral root, dried & processed. It has been used for diabetes and urinary frequency treatments.

AIM OF THE STUDY

We investigate effects of BWDHW on cyclophosphamide (CYP)-induced ongoing bladder overactivity and acidic adenosine triphosphate (ATP) solution-induced hyperactivity on rat's prestimulated bladder.

MATERIAL AND METHODS

Female Wistar rats were injected with intraperitoneal CYP (100mg/kg) or saline respectively. Rats were treated with BWDHW (90mg/kg/day) or vehicle for the next five days. After treatments animals were evaluated both in metabolic cage model and then by cystometry. Acidic ATP solution (5mM, pH 3.3) was instilled to provoke bladder hyperactivity. Bladder mucosa and muscle proteins were assessed by Western blotting.

RESULTS

As compared to the controls, the CYP group showed significantly decreased mean cystometric intercontractile interval and increased micturition frequency, whereas the CYP/BWDWH group did not. The CYP group had significant protein overexpression in mucosal M2, M3, P2X2, and P2X3 receptors as well as detrusor M2 and M3 receptors. However, the CYP/BWDWH group had insignificant changes from controls. In the provoking test, the control/BWDHW and CYP/BWDHW groups were less affected by acidic ATP stimulation of intercontractile interval changes than the control group. Compared to the control group, the control/BWDHW group showed significantly lower mucosal P2X3 protein expression and the CYP group showed significant mucosal TRPV1 protein upregulation after the provoking test.

CONCLUSION

BWDHW treatment can ameliorate CYP-induced ongoing bladder overactivity and suppress mucosal P2X2, P2X3, M2, and M3 receptor protein overexpression, as well as detrusor M2 and M3 receptor protein overexpression. BWDHW pretreatment can reduce acidic ATP solution-provoked hyperactivity by preventing TRPV1 receptor overexpression in CYP-treated bladder mucosa and inhibiting P2X3 receptor overexpression in naïve bladder mucosa.

Urothelial Dysfunction and Chronic Inflammation in Diabetic Patients with Overactive Bladder

OBJECTIVES

To investigate urothelial dysfunction, suburothelial inflammation, and muscarinic receptor expression in diabetic patients with overactive bladder (OAB).

METHODS

A total 19 patients with OAB and diabetes mellitus (DM), 14 OAB patients without DM, and 10 healthy control subjects were enrolled in the study. Immunofluorescence staining of E-cadherin, zonula occludens-1 (ZO-1), tryptase (mast cell activation), and apoptosis tests on the bladder urothelium and suburothelium were performed. Tissue muscarinic receptor M2, M3, and purinergic receptor P2X3 levels were measured by Western blotting. Video urodynamic studies were analyzed in relation to immunofluorescence and western blotting results.

RESULTS

The mean age of the controls, OAB patients without and with DM were comparable (62.9 ± 6.9, 58.4 ± 21.3, and 68.9 ± 11.3 years, respectively, P = 0.25). E-cadherin and mast cell expression in the bladder urothelium samples of the DM-OAB group and the OAB group without DM differed significantly from those of the control group (all P < 0.05). However, immunofluorescence analyses including E-cadherin, mast cells, apoptotic cell counts, and ZO-1 were comparable between OAB patients with and without DM. In addition, M3 muscarinic protein expression in the bladders of OAB patients with and without DM was significantly higher than that in the control subjects. The video urodynamic parameters did not correlate with the immunofluorescence data, M2 and M3 muscarinic receptor data, or P2X3 protein expression.

CONCLUSION

Urothelial dysfunction and chronic suburothelial inflammation may contribute to the pathogeneses of OAB. However, DM does not aggravate the severity of urothelial inflammation in OAB patients.

Therapeutic modulation of urinary bladder function: multiple targets at multiple levels

Storage dysfunction of the urinary bladder, specifically overactive bladder syndrome, is a condition that occurs frequently in the general population. Historically, pathophysiological and treatment concepts related to overactive bladder have focused on smooth muscle cells. Although these are the central effector, numerous anatomic structures are involved in their regulation, including the urothelium, afferent and efferent nerves, and the central nervous system. Each of these structures involves receptors for—and the urothelium itself also releases—many mediators. Moreover, hypoperfusion, hypertrophy, and fibrosis can affect bladder function. Established treatments such as muscarinic antagonists, β-adrenoceptor agonists, and onabotulinumtoxinA each work in part through their effects on the urothelium and afferent nerves, as do α1-adrenoceptor antagonists in the treatment of voiding dysfunction associated with benign prostatic hyperplasia; however, none of these treatments are specifically targeted to the urothelium and afferent nerves. It remains to be explored whether future treatments that specifically act at one of these structures will provide a therapeutic advantage.

Tadalafil effect on metabolic syndrome-associated bladder alterations: an experimental study in a rabbit model

INTRODUCTION

Metabolic syndrome (MetS) and lower urinary tract symptoms (LUTS) are often associated. Bladder detrusor hyper-contractility-a major LUTS determinant-is characterized by increased Ras homolog gene family, member A/Rho-associated protein kinase (RhoA/ROCK) signaling, which is often upregulated in MetS.

AIM

This study investigated the effects of tadalafil dosing on RhoA/ROCK signaling in bladder, in a rabbit model of high-fat diet (HFD)-induced MetS.

METHODS

Adult male rabbits feeding a HFD for 12 weeks. A subset of HFD animals was treated with tadalafil (2 mg/kg/day, 1 week: the last of the 12 weeks) and compared with HFD and control (feeding a regular diet) rabbits.

MAIN OUTCOME MEASURES

In vitro contractility studies to evaluate the relaxant effect of the selective ROCK inhibitor, Y-27632, in carbachol precontracted bladder strips. Evaluation of RhoA activation by its membrane translocation. Immunohistochemistry for ROCK expression has been performed to evaluate ROCK expression in bladder from the different experimental groups. mRNA expression of inflammation, pro-fibrotic markers by quantitative RT-PCR has been performed to evaluate the effect of tadalafil on MetS-induced inflammation and fibrosis within the bladder. The in vitro effect of tadalafil on RhoA/ROCK signaling in bladder smooth muscle cells was evaluated by using chemotaxis assay.

RESULTS

Bladder strips from HFD rabbits showed hyper-responsiveness to Y-27632, indicating RhoA/ROCK overactivity in HFD bladder compared with matched controls. Accordingly, the fraction of activated (translocated to the membrane) RhoA as well as ROCK expression are increased in HFD bladder. Tadalafil dosing normalized HFD-induced bladder hypersensitivity to Y-27632, by reducing RhoA membrane translocation and ROCK overexpression. Tadalafil dosing reduced mRNA expression of inflammatory, pro-fibrotic, and hypoxia markers. A direct inhibitory effect of tadalafil on RhoA/ROCK signaling in bladder smooth muscle cell was demonstrated by using chemotaxis assay. Pre-treatment with tadalafil inhibited both basal and PDGF-induced migration of bladder smooth muscle cells.

CONCLUSIONS

Tadalafil dosing reduced RhoA/ROCK signaling and smooth muscle overactivity in an animal model of MetS-associated bladder alterations. Our findings suggest a novel mechanism of action of tadalafil in alleviating LUTS in MetS patients.

Alterations in peripheral purinergic and muscarinic signaling of rat bladder after long-term fructose-induced metabolic syndrome

PURPOSE

We explored the pathophysiologic mechanisms of long-term fructose-induced lower urinary tract symptoms (LUTS) in rats.

METHODS

Male Wistar rats were fed with fructose for 3 or 6 months. Biochemical and transcystometric parameters were compared between fructose-fed and age-matched normal-diet rats. Pelvic nerve and external urethral sphincter-electromyogram activity recordings were performed to investigate fructose effects on neural control of bladders. Mitochondrial structure, ATP and acetylcholine content and purinergic and muscarinic cholinergic receptors were examined. Cytosolic cytochrome C staining by Western blot and immunocytochemistry for mitochondrial injury and PGP 9.5 stain for nerve density were also determined.

RESULTS

The fructose-fed rats with higher plasma triglyceride, LDL and fasting glucose levels displayed LUTS with increased frequency and suppressed voiding contractile amplitude in phase 1 and phase 2 duration versus normal-diet control. Fructose feeding altered the firing types in pelvic afferent and efferent nerves and external urethral sphincter-electromyogram activity. Increased mast cell number, disrupted and swollen mitochondria, increased cytosolic cytochrome C stain and expression and decreased nerve density in bladder smooth muscle layers appeared in the fructose-fed rats. Fructose feeding also significantly reduced ATP and acetylcholine content and enhanced protein expression of postsynaptic P(2)X(1), P(2)X(2) and P(2)X(3) purinergic receptors and M(2) and M(3) muscarinic cholinergic receptors expression in the smooth muscles of urinary bladder.

CONCLUSION

Long-term fructose feeding induced neuropathy and myopathy in the urinary bladders. Impaired mitochondrial integrity, reduced nerve density, ATP and acetylcholine content and upregulation of purinergic and muscarinic cholinergic receptors expression may contribute to the bladder dysfunction of fructose-fed animals.

Association of insulin resistance with overactive bladder in female patients

PURPOSE

Metabolic syndrome and obesity have been advocated to be risk factors for the development of overactive bladder (OAB). Additionally, insulin resistance is the underlying mechanism of metabolic syndrome. We aimed to investigate the association of insulin resistance with overactive bladder in female patients.

METHODS

We prospectively conducted the study in our urology department. Female patients aged between 30 and 76 years old applied to our policlinics with or without OAB symptoms were enrolled. One hundred and twenty-two patients with OAB and 62 age-matched controls without OAB were included into the study. Fasting serum insulin, glucose, high-density lipoprotein (HDL-c), and triglycerides levels were measured. Insulin resistance value was obtained via the homeostasis model assessment of insulin resistance (HOMA-IR) calculator. The chi-square and Mann-Whitney U tests were used to compare differences in variables.

RESULTS

Serum insulin level was found higher in female patients with OAB (11.5±6.2 µU/mL) relative to controls (6.4±2.1 µU/mL), statistically significant (P=0.036). In addition, HOMA-IR was significantly found higher in the OAB group, 2.86 (0.76 to 17.04) in comparison to controls, 1.32 (0.67 to 224), P=0.018. High-density lipoprotein cholesterol levels (HDL-c) were significantly found lower in females with OAB.

CONCLUSIONS

Insulin resistance can be associated to overactive bladder and may play significant role in pathogenesis.

Impact of diabetes mellitus on bladder uroepithelial cells

Diabetic bladder dysfunction (DBD), a prevalent complication of diabetes mellitus (DM), is characterized by a broad spectrum of symptoms including urinary urgency, frequency, and incontinence. As DBD is commonly diagnosed late, it is important to understand the chronic impact of DM on bladder tissues. While changes in bladder smooth muscle and innervation have been reported in diabetic patients, the impact of DM on the specialized epithelial lining of the urinary bladder, the urothelium (UT), is largely unknown. Quantitative polymerase chain reaction analysis and electron microscopy were used to evaluate UT gene expression and cell morphology 3, 9, and 20 wk following streptozotocin (STZ) induction of DM in female Sprague-Dawley rats compared with age-matched control tissue. Desquamation of superficial (umbrella) cells was noted at 9 wk DM, indicating a possible breach in barrier function. One causative factor may be metabolic burden due to chronic hyperglycemia, suggested by upregulation of the polyol pathway and glucose transport genes in DM UT. While superficial UT repopulation occurred by 20 wk DM, the phenotype was different, with significant upregulation of receptors associated with UT mechanosensation (transient receptor potential vanilloid subfamily member 1; TRPV1) and UT autocrine/paracrine signaling (acetylcholine receptors AChR-M2 and -M3, purinergic receptors P2X(2) and P2X(3)). Compromised barrier function and alterations in UT mechanosensitivity and cell signaling could contribute to bladder instability, hyperactivity, and altered bladder sensation by modulating activity of afferent nerve endings, which appose the urothelium. Our results show that DM impacts urothelial homeostasis and may contribute to the underlying mechanisms of DBD.

Role of PKC and CaV1.2 in detrusor overactivity in a model of obesity associated with insulin resistance in mice

Obesity/metabolic syndrome are common risk factors for overactive bladder. This study aimed to investigate the functional and molecular changes of detrusor smooth muscle (DSM) in high-fat insulin resistant obese mice, focusing on the role of protein kinase C (PKC) and Ca(v)1.2 in causing bladder dysfunction. Male C57BL/6 mice were fed with high-fat diet for 10 weeks. In vitro functional responses and cystometry, as well as PKC and Ca(v)1.2 expression in bladder were evaluated. Obese mice exhibited higher body weight, epididymal fat mass, fasting glucose and insulin resistance. Carbachol (0.001-100 µM), α,β-methylene ATP (1-10 µM), KCl (1-300 mM), extracellular Ca(2+) (0.01-100 mM) and phorbol-12,13-dibutyrate (PDBu; 0.001-3 µM) all produced greater DSM contractions in obese mice, which were fully reversed by the Ca(v)1.2 blocker amlodipine. Cystometry evidenced augmented frequency, non-void contractions and post-void pressure in obese mice that were also prevented by amlodipine. Metformin treatment improved the insulin sensitivity, and normalized the in vitro bladder hypercontractility and cystometric dysfunction in obese mice. The PKC inhibitor GF109203X (1 µM) also reduced the carbachol induced contractions. PKC protein expression was markedly higher in bladder tissues from obese mice, which was normalized by metformin treatment. The Ca(v)1.2 channel protein expression was not modified in any experimental group. Our findings show that Ca(v)1.2 blockade and improvement of insulin sensitization restores the enhanced PKC protein expression in bladder tissues and normalizes the overactive detrusor. It is likely that insulin resistance importantly contributes for the pathophysiology of this urological disorder in obese mice.

Sensory dysfunction of bladder mucosa and bladder oversensitivity in a rat model of metabolic syndrome

Purpose

To study the role of sensory dysfunction of bladder mucosa in bladder oversensitivity of rats with metabolic syndrome.

Materials and Methods

Female Wistar rats were fed a fructose-rich diet (60%) or a normal diet for 3 months. Based on cystometry, the fructose-fed rats (FFRs) were divided into a group with normal detrusor function or detrusor overactivity (DO). Acidic adenosine triphosphate (ATP) solution (5mM, pH 3.3) was used to elicit reflex micturition. Cystometric parameters were evaluated before and after drug administration. Functional proteins of the bladder mucosa were assessed by western blotting.

Results

Compared to the controls, intravesical acidic ATP solution instillation induced a significant increase in provoked phasic contractions in both FFR groups and a significant decrease in the mean functional bladder capacity of group DO. Pretreatment with capsaicin for C-fiber desentization, intravesical liposome for mucosal protection, or intravenous pyridoxal 5-phosphate 6-azophenyl-2′,4′-disulfonic acid for antagonized purinergic receptors can interfere with the urodynamic effects of intravesical ATP in FFRs and controls. Over-expression of TRPV1, P2X₃, and iNOS proteins, and down-regulation of eNOS proteins were observed in the bladder mucosa of both fructose-fed groups.

Conclusions

Alterations of sensory receptors and enzymes in the bladder mucosa, including over-expression of TRPV1, P2X₃, and iNOS proteins, can precipitate the emergence of bladder phasic contractions and oversensitivity through the activation of C-afferents during acidic ATP solution stimulation in FFRs. The down-regulation of eNOS protein in the bladder mucosa of FFRs may lead to a failure to suppress bladder oversensitivity and phasic contractions. Sensory dysfunction of bladder mucosa and DO causing by metabolic syndrome are easier to elicit bladder oversensitivity to certain urothelium stimuli.

Neuroprotection of green tea catechins on surgical menopause-induced overactive bladder in a rat model

OBJECTIVE

A rat model of ovariectomy-induced voiding dysfunction has been established, which mimicked the urge incontinence in postmenopausal women. Previous studies have identified strong anti-inflammatory/antioxidant properties of green tea and its associated polyphenols. The aim of this study was to evaluate whether the green tea extract, epigallocatechin gallate (EGCG), could prevent an ovariectomy-induced overactive bladder.

METHODS

The study included 48 female Sprague-Dawley rats, which were divided into four groups. After bilateral ovariectomy during the following 6-month period, 12 rats received an intraperitoneal injection of saline, 24 rats received either a low-dose (1 μM kg(-1) d(-1)) or a high-dose (10 μM kg(-1) d(-1)) EGCG intraperitoneal injection. The sham group consisted of twelve rats that were not ovariectomized. In vivo isovolumetric cystometrograms were performed in all groups before the animals were euthanized. The immunofluorescence study used neurofilament stains to evaluate intramural nerve damage. Western immunoblots and real-time polymerase chain reaction were performed to determine M2 and M3 muscarinic cholinergic receptors (MChRs) at both protein and messenger RNA (mRNA) expressions.

RESULTS

Long-term ovariectomy significantly increased non-voiding contractions, whereas treatment with EGCG significantly attenuated the frequency of non-voiding contractions. Ovariectomy significantly decreased the numbers of neurofilament and increased M2 and M3 MChR protein and mRNA expressions. Treatment with EGCG restored the amount of neurofilament staining and decreased M2 and M3 MChR protein and mRNA overexpressions.

CONCLUSIONS

This study confirmed that ovary hormone deficiency induced overactive bladder dysfunction via intramural nerve damage and muscarinic receptor overexpression. EGCG prevented ovariectomy-induced bladder dysfunction through neuroprotective effects in a dose-dependent fashion.

Metabolic syndrome in female patients with overactive bladder

OBJECTIVE

To investigate the relevance of metabolic syndrome in the etiopathogenesis of overactive bladder in female patients. It has been shown that obesity has been associated with overactive bladder (OAB), and the metabolic syndrome and insulin resistance have been related to the annual growth rates of prostate and lower urinary tract symptoms.

METHODS

Female patients applying to our policlinics with OAB symptoms or other urologic complaints were enrolled in the study. The International Diabetes Federation criteria were used for the definition of the metabolic syndrome. The chi-square, Student t, and Mann-Whitney U tests and logistic regression analyses were used to compare differences in the variables.

RESULTS

The metabolic syndrome was diagnosed in 201 (64%) of 313 patients with OAB and 73 (35%) of 208 patients without OAB. The difference was statistically significant (P=.002). A larger waist circumference, greater body mass index, low high-density lipoprotein level, and incidence of hypertension were significantly greater statistically in the OAB group than in the controls.

CONCLUSION

The metabolic syndrome correlates highly with OAB in female patients. The metabolic syndrome can be an etiologic pathway for the onset of symptoms.

Urological aspects of the metabolic syndrome

The metabolic syndrome is common in countries with Western lifestyles. It comprises a number of disorders-including insulin resistance, hypertension and obesity-that all act as risk factors for cardiovascular diseases. Urological diseases have also been linked to the metabolic syndrome. Most established aspects of the metabolic syndrome are linked to benign prostatic hyperplasia (BPH) and prostate cancer. Fasting plasma insulin, in particular, has been linked to BPH and incident, aggressive and lethal prostate cancer. The metabolic syndrome has also been shown to be associated with nonprostatic urological conditions such as male hypogonadism, nephrolithiasis, overactive bladder and erectile dysfunction, although data on these conditions are still sparse. Overall, the results of studies on urological aspects of the metabolic syndrome seem to indicate that BPH and prostate cancer could be regarded as two new aspects of the metabolic syndrome, and that an increased insulin level is a common underlying aberration that promotes both BPH and clinical prostate cancer. Urologists need to be aware of the effect that the metabolic syndrome has on urological disorders and should transfer this knowledge to their patients.