Chronic inflammation in the pathogenesis of benign prostatic hyperplasia

Proteomic analysis of patient tissue reveals PSA protein in the stroma of benign prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) is an age-related disease frequently associated with lower urinary tract symptoms (LUTS) that involves hyperplasia of both epithelial and stromal cells. Stromal fibrosis is a distinctive feature of BPH, but the exact mechanisms underlying this phenomenon are poorly understood.

METHODS

In the current study, proteomics analyses were utilized to identify proteins altered in the BPH stromal compartment from patients with symptomatic BPH. Stromal cells were isolated from histological nodules of BPH by laser capture microdissection (LCM) and subjected to liquid chromatography/mass spectrometry.

RESULTS

Proteins identified included several stromal-specific proteins involved in extracellular matrix (ECM) remodeling, focal adhesion, and cellular junctions. Additionally, the proteomics array identified the presence of luminal epithelial secretory protein PSA. Immunostaining, ELISA, and in situ hybridization analyses of BPH tissues verified the presence of PSA protein but absence of PSA mRNA in the stromal compartment. E-cadherin was down-regulated in BPH epithelial cells compared to normal adjacent tissues, suggesting that alteration of cellular junctions could contribute to the presence of luminal epithelial secreted proteins PSA and KLK2 in the stromal compartment.

CONCLUSIONS

The above findings suggest that the presence of secreted proteins PSA and KLK2 from prostate luminal epithelial cells in BPH stroma is a hallmark of BPH nodules, which could in part be due to alterations in cellular junction proteins and/or increased epithelial barrier permeability. Elucidating the cause and consequence of these secreted proteins in the stromal compartment of BPH may lead to new understanding of BPH pathogenesis as well as approaches to prevent and/or treat this common disease.

Surgical intervention for symptomatic benign prostatic hyperplasia is correlated with expression of the AP-1 transcription factor network

BACKGROUND

Approximately one-third of patients fail medical treatment for benign prostatic hyperplasia and associated lower urinary tract symptoms (BPH/LUTS) requiring surgical intervention. Our purpose was to establish a molecular characterization for patients undergoing surgical intervention for LUTS to address therapeutic deficiencies.

METHODS

Clinical, molecular, and histopathological profiles were analyzed in 26 patients undergoing surgery for severe LUTS. Incidental transitional zone nodules were isolated from 37 patients with mild symptoms undergoing radical prostatectomy. Clinical parameters including age, prostate volume, medication, prostate specific antigen, symptom score, body mass index, and incidence of diabetes were collected. Multivariate logistic regression analysis with adjustments for potential confounding variables was used to examine associations between patient clinical characteristics and molecular targets identified through molecular profiling.

RESULTS

Compared to incidental BPH, progressive symptomatic BPH was associated with increased expression of the activating protein-1 transcription factor/chemokine network. As expected, inverse correlations were drawn between androgen receptor levels and age, as well as between 5α-reductase inhibitor (5ARI) treatment and tissue prostate specific antigen levels; however, a novel association was also drawn between 5ARI treatment and increased c-FOS expression.

CONCLUSIONS

This study provides molecular evidence that a network of pro-inflammatory activating protein-1 transcription factors and associated chemokines are highly enriched in symptomatic prostate disease, a profile that molecularly categorizes with many other chronic autoimmune diseases. Because 5ARI treatment was associated with increased c-FOS expression, future studies should explore whether increased activating protein-1 proteins are causal factors in the development of symptomatic prostate disease, inflammation or resistance to traditional hormonal therapy.

Inhibitory effects by ayurvedic plants on prostate enlargement induced in rats

Background:

Ayurveda recommends several plants and plant preparation for conditions of urogenital disorders as per its principles. Objectives: Ayurvedic plants Tamala (Cinnamomum tamala); Daruhalad (Berberis aristata); Ativish (Aconitum heterophyllum) were studied for mechanisms of prostatic hyperplasia induced in rats.

Materials and Methods:

Prostatic enlargement was induced in castrated rats by testosterone injection s.c. for 21 days and simultaneously plants were dosed orally daily. On day 22 rats were sacrificed and prostate was removed; weight and volume of prostate was measured; histopathology performed. Inflammation was induced by injecting carrageenan in rat hind paw and inhibition was studied by measuring rat paw oedema at different time points.

Results:

Tamala showed significant effect where it reduced prostatic enlargement and improved hyperplastic changes, while Daruhalad and Ativisha did not show any significant effect. All of them showed mild to moderate anti-inflammatory activity.

Conclusion:

Study concludes that Tamala may benefit in prostate disorder by virtue of inhibition of androgen mechanisms in prostate and modulating inflammatory mediators in prostate. Daruhalad and Ativisha did not show any effect in this model of prostate enlargement while the anti-inflammatory effect may propose one of the useful properties when included in various formulations.

Low intraprostatic DHT promotes the infiltration of CD8+ T cells in BPH tissues via modulation of CCL5 secretion

Clinical studies suggested thatandrogen might be associated with infiltrating T cells in prostate of benign prostatic hyperplasia (BPH) patients, but detail of T-cell subset and mechanism still remained unclear. The present study tested the hypothesis that intraprostatic 5α-dihydrotestosterone (DHT) exerts effects on T cells recruitment by BPH epithelial cells. Prostate tissues from 64 cases of BPH patients after transurethral resection of prostate (TURP) were divided into 2 groups: (1) no medication history; (2) administration of 5α-reductase type II inhibitor-finasteride 5 mg daily for at least 6 months before surgery. Group 2 presented significantly higher CD8+ T cells infiltration than group 1, but no changes in CD4+ T cells (immunohistochemistry and flow cytometry). In vitro study more CD8+ T cell migrated to the prostate tissue lysates from group 2 and BPH-1 cells in low DHT condition. Transcription of chemokine (C-C motif) Ligand 5 (CCL5) mRNA in BPH-1 cells and chemokine (C-C motif) receptor 5 (CCR5) mRNA in CD8+ T cells were upregulated in low DHT condition (q-PCR). CCL5 expression was also identified to be higher in group 2 prostate tissues by IHC. This study suggested that intraprostatic DHT may participate in regulating inflammatory response which was induced by human prostatic epithelial cell, via modulating CCL5 secretion.

Benign prostatic hyperplasia: a new metabolic disease?

BACKGROUND

Benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS) are conditions extremely prevalent in the aging male. Although androgens are involved in prostate growth during developmental age, their role in the pathogenesis of BPH/LUTS is debated. Recent data indicate that low testosterone and high estradiol favor disease progression. In addition, the role of other determinants, such as metabolic syndrome or prostate inflammation, is emerging.

AIM

We reviewed the evidence regarding the pathogenesis of BPH/LUTS with particular attention to metabolic influence.

MATERIALS AND METHODS

A review of published evidence was performed using Medline.

RESULTS

Available evidence shows that a three-hit hypothesis can be drawn. An overt, or even a subclinical, bacterial or viral infection could induce prostatic inflammation (first hit) that could be autosustained or exacerbated by the presence of an altered metabolism and in particular by hypercholesterolemia (second hit). Hypogonadism and/or hyperestrogenism could act as a third hit, favoring the maintenance of this inflammatory state. The combined action of all three hits, or even two of them, may result in overexpression of Toll-like receptors (TLRs), transformation of prostatic cells into antigen-presenting cells and activation of resident human prostate-associated lymphoid tissue ending in overproduction of growth factors which, in turn, will induce prostate remodeling and further prostate enlargement. The mechanical obstruction, along with the direct action of the unfavorable metabolic and hormonal milieu on the bladder neck, helps in generating LUTS.

CONCLUSION

Inflammation, dyslipidemia and altered sex-steroid milieu mutually concur in determining BPH/LUTS.

Increased risk of benign prostate hyperplasia in sleep apnea patients: a nationwide population-based study

Background

Sleep apnea (SA) is a common sleep disorder characterized by chronic intermittent hypoxia (IH). Chronic IH induces systemic inflammatory processes, which can cause tissue damage and contribute to prostatic enlargement. The purpose of this study was to evaluate the association between benign prostate hyperplasia (BPH) and SA in a Taiwanese population.

Methods

The study population was identified from Taiwan’s National Health Insurance Research Database (NHIRD) and contained 202 SA patients and 1010 control patients. The study cohort consisted of men aged ≥30 years who were newly diagnosed with SA between January 1997 and December 2005. Each patient was monitored for 5 years from the index date for the development of BPH. A Cox regression analysis was used to calculate the hazard ratios (HRs) for BPH in the SA and control patients.

Results

During the 5-year follow-up, 18 SA patients (8.9%) and 32 non-SA control patients (3.2%) developed BPH. The adjusted HR for BPH was 2.35-fold higher in the patients with SA than in the control patients (95% confidence interval (CI) 1.28–4.29, P<.01). We further divided the SA patients into 4 age groups. After adjusting for potential confounding factors, the highest adjusted HR for BPH in the SA patients compared with the control patients was 5.59 (95% CI = 2.19–14.31, P<.001) in the patients aged between 51 and 65 years.

Conclusion

Our study results indicate that patients with SA are associated with increased longitudinal risk of BPH development, and that the effects of SA on BPH development are age-dependent.

Age-related histological and zinc content changes in adult nonhyperplastic prostate glands

To clarify age-related histological and Zn content changes in nonhyperplastic adult prostate glands, a quantitative morphometric and energy-dispersive X-ray fluorescence analyses were performed. The prostates were obtained from autopsies of 63 subjects aged 21-70 years who died mainly from trauma. It was found that histologically normal prostate tissue undergoes substantial changes throughout aging. These changes are reflected in an increase of the percent volume of the glandular lumen for the third to fifth decades, reaching a maximum for the decade 41-50 years. Over the same period, the percent volume of the stroma remains steady, but the percent volume of epithelium decreases, approximately, linearly with age. The percent volume of glandular lumen (reflects the volume of prostatic fluid) in the prostate gland of men aged 41 to 50 years is 1.5-fold higher than that in men aged 21 to 30 years, but the epithelium/lumen (prostatic fluid) ratio is approximately twofold lower. This suggests that accumulation of the prostatic fluid develops from 30 to 50 years of age. This accumulation of the prostatic fluid results in an increase of the Zn mass fraction in the prostate. In turn, when the intraprostatic Zn level exceeds a certain level by the end of the fifth decade, it begins to work as a trigger for different factors, all of which increase the proliferation of stromal cells. Deductions from these results allow possible partial explanations of both relevant prostatic aging mechanisms and the effects of dietary interventions using supplementary Zn.

Benign prostatic hyperplasia: a new metabolic disease of the aging male and its correlation with sexual dysfunctions

Metabolic syndrome (MetS) is a well-recognized cluster of cardiovascular (CV) risk factors including obesity, hypertension, dyslipidemia, and hyperglycaemia, closely associated with an increased risk of forthcoming cardiovascular disease and type 2 diabetes mellitus. Emerging evidence indicates that benign prostate hyperplasia (BPH) and its related lower urinary tract symptoms (LUTS) represent other clinical conditions frequently observed in subjects with MetS. Several modifiable factors involved in MetS determinism, such as inadequate diet, lack of physical exercise, and smoking and drinking behaviours are emerging as main contributors to the development of BPH. The pathogenetic mechanisms underlying the connection between MetS and BPH have not been completely clarified. MetS and its components, hypogonadism, and prostate inflammation probably play an important role in inducing BPH/LUTS. Although historically considered as a "normal" consequence of the aging process, BPH/LUTS should now be faced proactively, as a preventable disorder of the elderly. Type of diet and level of physical activity are now considered important factors affecting prostate health in the aging male. However, whether physical exercise, weight loss, and modifications of dietary habit can really alter the natural history of BPH/LUTS remains to be determined. Further research is advisable to better clarify these points.

Opposite effects of tamoxifen on metabolic syndrome-induced bladder and prostate alterations: a role for GPR30/GPER?

BACKGROUND

BPH and LUTS have been associated to obesity, hypogonadism, and metabolic syndrome (MetS). MetS-induced prostate and bladder alterations, including inflammation and tissue remodeling, have been related to a low-testosterone and high-estrogen milieu. In addition to ERs, GPR30/GPER is able to mediate several estrogenic non-genomic actions.

METHODS

Supplementing a subgroup of MetS rabbits with tamoxifen, we analyzed the in vivo effects on MetS-induced prostate and bladder alterations. The effects of selective ER/GPER ligands and GPER silencing on prostate inflammation were also studied in vitro using hBPH cells.

RESULTS

ERα, ERβ, and PR expression was upregulated in MetS bladder, where tamoxifen decreased ERα and PR expression, further stimulating ERβ. In addition, tamoxifen-dosing decreased MetS-induced overexpression of inflammatory and tissue remodeling genes. In prostate, sex steroid receptors, pro-inflammatory and pro-fibrotic genes were upregulated in MetS. However, tamoxifen did not affect them and even increased COX-2. In hBPH cells, 17β-estradiol increased IL-8 secretion, an effect blunted by co-treatment with GPER antagonist G15 but not by ER antagonist ICI 182,780, which further increased it. GPER agonist G1 dose-dependently (IC50  = 1.6 nM) induced IL-8 secretion. In vitro analysis demonstrated that GPER silencing reverted these stimulatory effects.

CONCLUSIONS

GPER can be considered the main mediator of estrogen action in prostate, whereas in bladder the mechanism appears to rely on ERα, as indicated by in vivo experiments with tamoxifen dosing. Limiting the effects of the MetS-induced estrogen action via GPER could offer new perspectives in the management of BPH/LUTS, whereas tamoxifen dosing showed potential benefits in bladder.

Prostate volume and growth during testosterone replacement therapy is related to visceral obesity in Klinefelter syndrome

OBJECTIVE

Klinefelter syndrome (KS) is a chromosomal alteration characterized by increased risk of metabolic syndrome, mainly caused by visceral obesity. In the last years, obesity has been studied as a potential risk factor for prostate disease and recently a link has been demonstrated between visceral adiposity with prostate volume. The aim of this study was to analyze the relationship between obesity and prostate volume and growth during testosterone therapy in KS subjects.

DESIGN AND METHODS

We evaluated reproductive hormones, metabolic parameters, anthropometric measures, PSA, and prostate volume in 121 naïve non-mosaic KS patients and 60 age-matched healthy male controls. Fifty-six KS hypogonadic subjects were treated with testosterone-gel 2% and reevaluated after 18 months of treatment.

RESULTS

Prostate volume in KS was positively related to waist circumference (WC). The KS group with WC ≥94 cm had significantly higher prostate volume, BMI, insulin plasma levels, homeostasis model assessment index, total cholesterol, triglycerides, and glycemia with respect to the KS group with WC <94 cm. After testosterone replacement therapy, only hypogonadic KS men with WC ≥94 cm had a statistically significant increase in prostate volume. Furthermore, in untreated KS subjects, prostate volume showed a statistically significant increase after 18 months of follow-up only in subjects with WC ≥94 cm.

CONCLUSIONS

This study showed that visceral obesity, insulin resistance, and lipid and glucose metabolism alterations are associated with prostate volume and growth during testosterone replacement therapy in KS, independently from androgen or estrogen levels. These latter findings might provide the basis for a better management and follow-up of KS subjects.

PDE5 inhibitors blunt inflammation in human BPH: a potential mechanism of action for PDE5 inhibitors in LUTS

BACKGROUND

Metabolic syndrome (MetS) and benign prostate hyperplasia (BPH)/low urinary tract symptoms (LUTS) are often comorbid. Chronic inflammation is one of the putative links between these diseases. Phosphodiesterase type 5 inhibitors (PDE5i) are recognized as an effective treatment of BPH-related LUTS. One proposed mechanism of action of PDE5 is the inhibition of intraprostatic inflammation. In this study we investigate whether PDE5i could blunt inflammation in the human prostate.

METHODS

Evaluation of the effect of tadalafil and vardenafil on secretion of interleukin 8 (IL-8, a surrogate marker of prostate inflammation) by human myofibroblast prostatic cells (hBPH) exposed to different inflammatory stimuli. We preliminary evaluate histological features of prostatic inflammatory infiltrates in BPH patients enrolled in a randomized, double bind, placebo controlled study aimed at investigating the efficacy of vardenafil (10 mg/day, for 12 weeks) on BPH/LUTS.

RESULTS

In vitro treatment with tadalafil or vardenafil on hBPH reduced IL-8 secretion induced by either TNFα or metabolic factors, including oxidized low-density lipoprotein, oxLDL, to the same extent as a PDE5-insensitive PKG agonist Sp-8-Br-PET-cGMP. These effects were reverted by the PKG inhibitor KT5823, suggesting a cGMP/PKG-dependency. Treatment with tadalafil or vardenafil significantly suppressed oxLDL receptor (LOX-1) expression. Histological evaluation of anti-CD45 staining (CD45 score) in prostatectomy specimens of BPH patients showed a positive association with MetS severity. Reduced HDL-cholesterol and elevated triglycerides were the only MetS factors significantly associated with CD45 score. In the MetS cohort there was a significant lower CD45 score in the vardenafil-arm versus the placebo-one.

Metabolic syndrome correlates with peri-urethral fibrosis secondary to chronic prostate inflammation: evidence of a link in a cohort of patients undergoing radical prostatectomy

OBJECTIVES

To investigate the pathological relationship between metabolic syndrome and peri-urethral fibrosis status secondary to chronic prostate inflammation.

METHODS

Peri-urethral prostate tissue from 80 consecutive patients who underwent retropubic radical prostatectomy for prostate cancer was analyzed. Patients were divided in two groups according to whether or not they had a diagnosis of metabolic syndrome. A 16-peri-urethral core bench biopsy was carried out on each radical prostatectomy specimen to evaluate the extent of peri-urethral inflammatory infiltrate, and collagen and elastin amount. Spearman's correlation analysis was used to test the association between variables. Furthermore, the data were used to define a bivariate logistic regression model in which the presence (>50% collagen amount for each patients) or absence (≤50% collagen amount) of fibrosis was analyzed after adjusting for clinical and pathological variables.

RESULTS

A significant difference was found between the two groups in terms of International Prostatic Symptoms Score (P < 0.05) and urodynamics findings (all P < 0.05). Patients with metabolic syndrome showed a more extended inflammatory infiltrate and higher peri-urethral collagen amount, along with a lower peri-urethral elastin amount (all P < 0.05). A positive correlation was observed between inflammation, International Prostatic Symptoms Score, Bladder Outlet Obstruction Index and collagen amount, whereas inflammation was inversely correlated with elastin amount. On multivariate logistic regression analysis, prostate inflammation and metabolic syndrome were the only independent predictors of peri-urethral fibrosis (OR 1.73, 1.52, respectively).

CONCLUSIONS

The present findings suggest that metabolic syndrome might represent an independent risk factor for prostate inflammation and fibrotic changes secondary to inflammation within the peri-urethral prostatic tissue.

Risks and benefits of late onset hypogonadism treatment: an expert opinion

Late-onset hypogonadism (LOH) is a syndromic condition that has a well-recognized association with sexual and reproductive failure. LOH is frequently associated with chronic conditions including cardiovascular diseases (CVD), obesity, osteoporosis, HIV infection, renal failure, and obstructive pulmonary diseases. Despite this evidence, in patients with these conditions, LOH is still only rarely investigated and testosterone replacement therapy (TRT) rarely considered. In this paper, we critically reviewed the available evidence on LOH treatment focusing on possible risks and benefits. Medical therapy of LOH should be individualized depending on the etiology of the disease and the patient's expectations. The fear of prostate cancer and the risk of erythrocytosis probably represent the main limitations of TRT in aging men. However, TRT in healthy older men in near physiological doses does not appear to incur serious adverse events, although regular monitoring of prostate-specific antigen and hematocrit levels is required. Available evidence also suggests that TRT might ameliorate central obesity and glycometabolic control in patients with metabolic syndrome and type 2 diabetes. In addition, TRT has been associated with an increase in bone mineral density in men with osteoporosis, with an improvement in lean body mass in subjects with human immunodeficiency virus infection or chronic obstructive pulmonary disease, as well as with peripheral oxygenation in patients with chronic kidney diseases. Despite this evidence, however, it should be recognized that the results of these trials were heterogeneous and limited by small sample sizes. Hence, further research is required regarding the long-term benefits and adverse effects of TRT in LOH.

Mechanisms of synergism between antagonists of growth hormone-releasing hormone and antagonists of luteinizing hormone-releasing hormone in shrinking experimental benign prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) affects aging men. Combined therapy with antagonists of growth hormone-releasing hormone (GHRH) and of luteinizing hormone-releasing hormone (LHRH or GnRH) induces prostate shrinkage in rat models. We investigated the mechanisms of action of this combination on cell cycle traverse and expression of prostatic genes.

METHODS

Effects of GHRH antagonist, JMR-132 (40 µg/day), the LHRH antagonist, cetrorelix (0.625 mg/kg), and their combination were evaluated on testosterone-induced benign prostatic hyperplasia in male Wistar rats. Influence of JMR-132, cetrorelix, and their combinations on cell viability was assessed by MTS assay in BPH-1 human prostate epithelial cells and WPMY-1 normal prostate stromal cells. Cell cycle was analyzed by laser flow cytometry. Real-time PCR arrays were performed.

RESULTS

The combination of antagonists caused marked shrinkage of rat prostate (29.5%). In vitro, JMR-132 plus cetrorelix (both 5µM) produced synergistic (57.4%) inhibition of growth of BPH-1 cells, but a lesser inhibition (46%) of WPMY-1 cells. Co-treatment of with JMR-132 plus cetrorelix induced a significant increase of BPH-1 cells blocked in S-phase plus cells with lower G0 /G1 and G2 /M DNA content. Significant changes in expression of >40 gene transcripts related to growth factors, inflammatory cytokines, and signal transduction were identified.

CONCLUSIONS

GHRH antagonist and LHRH antagonist combination potentiates rat prostate weight reduction and synergistically inhibits of growth of BPH-1 leading to cell cycle arrest in S-phase. These effects were lesser in normal stromal prostate cell line, WPMY-1. Our findings suggest that GHRH antagonists could be useful for BPH therapy, possibly in combination with LHRH antagonists.

Fat boosts, while androgen receptor activation counteracts, BPH-associated prostate inflammation

BACKGROUND

Metabolic syndrome (MetS) and benign prostate hyperplasia (BPH) are often comorbid. Chronic inflammation, a determinant pathogenic factor for BPH, is a putative link between the two conditions.

METHODS

In a multi-center cohort of BPH patients (n = 244) who underwent prostatectomy, we evaluated whether MetS is associated with prostatic inflammation in BPH specimens. In addition, we investigated the in vitro inflammatory effects of metabolic insults on human prostatic myofibroblastic cells (hBPH).

RESULTS

Inflammatory infiltrates score (IS) in prostatectomy specimens showed a step-wise association with the number of MetS factors present (P = 0.001). After adjusting for age, reduced HDL cholesterol, and elevated triglycerides were the only factors significantly associated with IS. Increased IS was also significantly associated with hypogonadism. In an age- and testosterone (T)-adjusted model, dyslipidemia was still associated with IS. To investigate whether metabolic factors could directly trigger prostate inflammation, we performed preliminary studies in myofibroblastic hBPH. Among the different factors, oxidized low-density lipoprotein (oxLDL) showed the highest secretion of IL-8 (>10-fold)-a surrogate marker of prostate inflammation--as well as IL-6, and bFGF. Co-treatment with DHT significantly inhibited oxLDL-induced secretion of IL-8, whilst an AR-antagonist, bicalutamide, reversed DHT effects. DHT suppresses oxLDL receptor (LOX-1) expression.

CONCLUSIONS

Our data suggest that fats and insulin could have a detrimental effect on prostate health, boosting inflammation, a key pathogenic factor in BPH. Conversely, beneficial effects of DHT in counteracting lipid- and insulin-induced prostatic alterations, suggest that T-via its conversion into DHT-may have unexpected beneficial effects on prostate health.

Correlation between benign prostatic hyperplasia and inflammation

PURPOSE OF REVIEW

This review aims to evaluate the available evidence on the role of prostatic inflammation in the pathogenesis and progression of benign prostatic hyperplasia (BPH).

RECENT FINDINGS

Although there is still no evidence of a causal relation, accumulating evidence suggests that inflammation may contribute to the development of BPH and lower urinary tract symptoms (LUTS). Inflammatory infiltrates are frequently observed in prostate tissue specimens from men with BPH and the presence or degree of inflammation has been found to be correlated with prostate volume and weight. The inflammatory injury may contribute to cytokine production by inflammatory cells driving local growth factor production and angiogenesis in the prostatic tissue. This proinflammatory microenvironment is closely related to BPH stromal hyperproliferation and tissue remodeling with a local hypoxia induced by increased oxygen demands by proliferating cells which supports chronic inflammation as a source of oxidative stress leading to tissue injury in infiltrating area.

SUMMARY

Although the pathogenesis of BPH is not yet fully understood and several mechanisms seem to be involved in the development and progression, recent studies strongly suggest that BPH is an immune inflammatory disease. The T-cell activity and associated autoimmune reaction seem to induce epithelial and stromal cell proliferation. Further understanding of the role of inflammation in BPH and clinical detection of this inflammation will expand the understanding of BPH pathogenesis and its histologic and clinical progression, allow risk stratification for patients presenting with BPH-related LUTS, and suggest novel treatment strategies.

Future direction in pharmacotherapy for non-neurogenic male lower urinary tract symptoms

BACKGROUND

The pathophysiology of male lower urinary tract symptoms (LUTS) is highly complex and multifactorial. The shift in perception that LUTS are not sex or organ specific has not been followed by significant innovations regarding the available drug classes.

OBJECTIVE

To review pathophysiologic mechanisms and clinical and experimental data related to the development of new pharmacologic treatments for male LUTS.

EVIDENCE ACQUISITION

The PubMed database was used to identify articles describing experimental and clinical studies of pathophysiologic mechanisms contributing to male LUTS and, supported by them, new pharmacotherapies with clinical or experimental evidence in the field.

EVIDENCE SYNTHESIS

Several pathologic processes (eg, androgen signaling, inflammation, and metabolic factors) and targets (eg, the urothelium, prostate, interstitial cells, detrusor, neurotransmitters, neuromodulators, and receptors) have been implicated in male LUTS. Some newly introduced drugs, such as phosphodiesterase type 5 inhibitors and β3-adrenergic agonists, have just started broad use in clinical practice. Drugs with potential benefit, such as vitamin D3 receptor analogs, gonadotropin-releasing hormone antagonists, cannabinoids, and drugs injected into the prostate, have been evaluated in experimental studies and have progressed to clinical trials. However, safety and efficacy data for these drugs are still scarce. Some compounds with interesting profiles have only been tested in experimental settings (eg, transient receptor potential channel blockers, Rho-kinase inhibitors, purinergic receptor blockers, and endothelin-converting enzyme inhibitors).

CONCLUSIONS

New pathophysiologic mechanisms of male LUTS are described that lead to the continuous development of new pharmacotherapies. To date, few drugs have been added to the current armamentarium, and several are in various phases of clinical or experimental investigation.

Androgen receptor roles in the development of benign prostate hyperplasia

Benign prostate hyperplasia (BPH) is a major cause of lower urinary tract symptoms, with an increased volume of transitional zone and associated with increased stromal cells. It is known that androgen/androgen receptor (AR) signaling plays a key role in development of BPH, and that blockade of this signaling decreases BPH volume and can relieve lower urinary tract symptoms, but the mechanisms of androgen/AR signaling in BPH development remain unclear, and the effectiveness of current drugs for treating BPH is still limited. The detailed mechanisms of androgen/AR signaling need to be clarified, and new therapies are needed for better treatment of BPH patients. This review focuses on roles of AR in epithelial and stromal cells in BPH development. In epithelial cells, AR may contribute to BPH development via epithelial cell-stromal cell interaction with alterations of epithelial-mesenchymal transition, leading to proliferation of stromal cells. Data from several mouse models with selective knockout of AR in stromal smooth-muscle cells and/or fibroblasts indicate that the AR in stromal cells can also promote BPH development. In prostatic inflammation, AR roles in infiltrating macrophages and epithelial and stromal cells have been linked to BPH development, which has led to discovery of new therapeutic targets. For example, targeting AR with the novel AR degradation enhancer, ASC-J9 offers a potential therapeutic approach against BPH development.

The use of a single daily dose of tadalafil to treat signs and symptoms of benign prostatic hyperplasia and erectile dysfunction

A strong and independent association between lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH) and erectile dysfunction (ED) has been widely evidenced in several clinical epidemiologic studies. Preclinical animal models have provided a great deal of information on potential common pathogenic mechanisms underlying these two clinical identities. Although the efficacy of the most commonly used treatments for LUTS/BPH is well defined, the negative impact of these treatments on sexual function – in particular, on ED – has triggered the search for new treatment options. In this regard, a new role for phosphodiesterase type 5 inhibitors in the treatment of LUTS/BPH and ED has been claimed. Tadalafil is one of the most extensively investigated phosphodiesterase type 5 inhibitors for this new indication. All evidence reported to date suggests that tadalafil 5 mg once daily is a safe and effective treatment option for both LUTS/BPH and ED.

Vitamin D receptor as a therapeutic target for benign prostatic hyperplasia

The bioactive form of vitamin D, 1α, 25-dihydroxyvitamin D3 (1α, 25(OH)2D3), is a secosteroid hormone that binds to the vitamin D receptor (VDR), a member of the nuclear receptor super-family expressed in many cell types, and modulates a variety of biological functions. 1α, 25(OH)2D3 is essential for bone and mineral homeostasis, but also regulates growth and differentiation of multiple cell types, and displays immunoregulatory and anti-inflammatory activities. The antiproliferative, prodifferentiative, antibacterial, immunomodulatory and anti-inflammatory properties of synthetic VDR agonists could be exploited to treat a variety of chronic inflammatory and autoimmune diseases, including benign prostatic hyperplasia (BPH). It has been hypothesized that VDR may influence both the risk of a variety of diseases and their occurrence and prognosis. However, earlier studies investigating the associations between specific VDR polymorphisms and various diseases often show controversial results. We performed a systematic review of the current literature on vitamin D and BPH using the PubMed and Web of Knowledge databases. The aim of this review is to summarize the current knowledge on the utility of the VDR gene regarding prostate growth as well as the pathogenesis and treatment of BPH, a complex syndrome characterized by a static component related to prostate overgrowth, a dynamic component responsible for urinary storage symptoms, and an inflammatory component. Despite the massive advances in recent decades, further research is needed to fully characterize the exact underlying mechanisms of VDR action on BPH and to comprehend how these cellular changes translate into clinical development in physical concert.

Mechanism of action of phosphodiesterase type 5 inhibition in metabolic syndrome-associated prostate alterations: an experimental study in the rabbit

BACKGROUND

Phosphodiesterase type 5 (PDE5) inhibitors improve benign prostatic hyperplasia (BPH)-related lower urinary tract symptoms (LUTS), often associated with metabolic syndrome (MetS). This study investigated the effects of PDE5 inhibition in the prostate of rabbits fed a high fat diet (HFD) for 12 weeks. HFD-rabbits develop the most important features of human MetS (glucose intolerance, dyslipidemia, increased abdominal adiposity, and hypertension), along with hypogonadism and LUT abnormalities (prostate and bladder inflammation/tissue remodeling).

METHODS

Gene expression was evaluated by quantitative RT-PCR. Prostate morphological changes and oxygenation were evaluated by immunohistochemistry.

RESULTS

HFD prostates showed increased PDE5 expression, suggesting a peculiar sensitivity of prostate to the action of PDE5 inhibitors during MetS. Accordingly, prostate PDE5 mRNA was negatively associated to plasma testosterone/estradiol ratio, whose reduction characterizes MetS, and positively with the expression in prostate of several genes exploring pathogenetic processes for BPH/LUTS, such as inflammation, leukocyte infiltration, and fibrosis/myofibroblast activation. Most of these genes was up-regulated by HFD, and significantly reduced by PDE5 inhibition, through either chronic (12 weeks) or, at a lower extent, acute (1-week) tadalafil dosing. Tadalafil was also able to reduce blood pressure and visceral fat in HFD rabbits, without changing any other MetS parameter. Interestingly, 1-week tadalafil administration to HFD rabbits, significantly blunted prostate inflammation (increased CD45 immunopositivity), fibrosis (reduced muscle/fiber ratio) and hypo-oxygenation, thus suggesting a potential curative effect of PDE5 inhibition on MetS-related prostate alterations.

CONCLUSIONS

Our data provide the experimental evidences to support the multiple potentiality of PDE5 inhibitors as a useful therapeutic tool in LUTS.

Effects of flavocoxid, a dual inhibitor of COX and 5-lipoxygenase enzymes, on benign prostatic hyperplasia

BACKGROUND AND PURPOSE

Inflammation plays a key role in the development of benign prostatic hyperplasia (BPH). Eicosanoids derived from the COX and 5-lipoxygenase (5-LOX) pathways are elevated in the enlarging prostate. Flavocoxid is a novel flavonoid-based 'dual inhibitor' of the COX and 5-LOX enzymes. This study evaluated the effects of flavocoxid in experimental BPH.

EXPERIMENTAL APPROACH

Rats were treated daily with testosterone propionate (3 mg·kg(-1)  s.c.) or its vehicle for 14 days to induce BPH. Animals receiving testosterone were randomized to receive vehicle (1 mL·kg(-1) , i.p.) or flavocoxid (20 mg·kg(-1) , i.p.) for 14 days. Histological changes, eicosanoid content and mRNA and protein levels for apoptosis-related proteins and growth factors were assayed in prostate tissue. The effects of flavocoxid were also tested on human prostate carcinoma PC3 cells.

KEY RESULTS

Flavocoxid reduced prostate weight and hyperplasia, blunted inducible expression of COX-2 and 5-LOX as well as the increased production of PGE(2) and leukotriene B(4) (LTB(4) ), enhanced pro-apoptotic Bax and caspase-9 and decreased the anti-apoptotic Bcl-2 mRNA. Flavocoxid also reduced EGF and VEGF expression. In PC3 cells, flavocoxid stimulated apoptosis and inhibited growth factor expression. Flavocoxid-mediated induction of apoptosis was inhibited by the pan-caspase inhibitor, Z-VAD-FMK, in PC3 cells, suggesting an essential role of caspases in flavocoxid-mediated apoptosis during prostatic growth.

CONCLUSION AND IMPLICATIONS

Our results show that a 'dual inhibitor' of the COX and 5-LOX enzymes, such as flavocoxid, might represent a rational approach to reduce BPH through modulation of eicosanoid production and a caspase-induced apoptotic mechanism.

The role of inflammatory mediators in the development of prostatic hyperplasia and prostate cancer

Benign prostatic hyperplasia and prostate cancer remain the most prevalent urologic health concerns affecting elderly men in their lifetime. Only 20% of benign prostatic hyperplasia and prostate cancer cases coexist in the same zone of the prostate and require a long time for initiation and progression. While the pathogenesis of both diseases is not fully understood, benign prostatic hyperplasia and prostate cancer are thought to have a multifactorial etiology, their incidence and prevalence are indeed affected by age and hormones, and they are associated with chronic prostatic inflammation. At least 20% of all human malignancies arise in a tissue microenvironment dominated by chronic or recurrent inflammation. In prostate malignancy, chronic inflammation is an extremely common histopathologic finding; its origin remains a subject of debate and may in fact be multifactorial. Emerging insights suggest that prostate epithelium damage potentially inflicted by multiple environmental factors such as infectious agents, dietary carcinogens, and hormones triggers procarcinogenic inflammatory processes and promotes cell transformation and disease development. Also, the coincidence of chronic inflammation and tumorigenesis in the peripheral zone has recently been linked by studies identifying so-called proliferative inflammatory atrophy as a possible precursor of prostatic intraepithelial neoplasia and prostate cancer. This paper will discuss the available evidence suggesting that chronic inflammation may be involved in the development and progression of chronic prostatic disease, although a direct causal role for chronic inflammation or infection in prostatic carcinogenesis has yet to be established in humans. Further basic and clinical research in the area, trying to understand the etiology of prostatic inflammation and its signaling pathway may help to identify new therapeutic targets and novel preventive strategies for reducing the risk of developing benign and malignant tumors of the prostate.

Metabolic syndrome and lower urinary tract symptoms: the role of inflammation

BACKGROUND

Epidemiological data indicate that lower urinary tract symptoms (LUTS)/BPH can be associated with metabolic syndrome (MetS). Chronic inflammation has been proposed as a candidate mechanism at the crossroad between these two clinical entities.Aim of study is to examine the correlation among pre-operatory LUTS/BPH severity, MetS features and inflammatory infiltrates in prostatectomy specimens.

METHODS

A total of 271 consecutive men treated with simple prostatectomy were retrospectively selected for this study in two tertiary referral centers for LUTS/BPH. Prostate diameters and volume were measured by transrectal ultrasound, LUTS scored by International Prostate Symptom Score (IPSS) and obstruction by uroflowmetry. The International Diabetes Federation and American Heart Association and the National Heart, Lung and Blood Institute was used to define MetS. The inflammatory infiltrate was investigated combining anatomic location, grade and extent of flogosis into the overall inflammatory score (IS); the glandular disruption (GD) was used as a further marker.

RESULTS

Eighty-six (31.7%) men were affected by MetS. Prostatic volume and anterior-posterior (AP) diameter were positively associated to the number of MetS components. Among MetS determinants, only dyslipidaemia (increased serum triglycerides and reduced serum high-density lipoprotein) was associated with an increased risk of having a prostatic volume >60 cm(3) (hazard ratio (HR) = 3.268, P < 0.001). A significant positive correlation between the presence of MetS and the IS was observed. MetS patients presented lower uroflowmetric parameters as compared with those without MetS (Maximum flow rate (Q(max)): 8.6 vs 10.1, P = 0.008 and average flow rate (Q(ave)): 4.6 vs 5.3, P = 0.033, respectively), and higher obstructive urinary symptoms score (P = 0.064). A positive correlation among both IS-GD and IPSS Score was also observed (adjusted r = 0.172, P = 0.008 and adjusted r = 0.128, P = 0.050).

CONCLUSIONS

MetS is associated with prostate volume, prostatic AP diameter and intraprostatic IS. The significantly positive association between MetS and prostatic AP diameter could support the observation that MetS patients presented lower uroflowmetric parameters. In conclusion, MetS can be regarded as a new determinant of prostate inflammation and BPH progression.

Inhibitors of 5α-reductase-related side effects in patients seeking medical care for sexual dysfunction

BACKGROUND

Despite their efficacy in the treatment of benign prostatic hyperplasia (BPH) the popularity of inhibitors of 5α-reductase (5ARI) is limited by their association with adverse sexual side effects. However, the real impact of 5ARI on sex hormones and sexual function is controversial.

AIM

To investigate the role of 5ARI therapy on hormonal parameters and sexual function in men already complaining of sexual problems.

MATERIALS AND METHODS

A consecutive series of 3837 men (mean age 63.5±12.8 yr) attending our outpatient clinic for sexual dysfunction was retrospectively studied. Several clinical, biochemical, and instrumental (penile color doppler ultrasound) factors were evaluated.

RESULTS

Among the patients studied, 78.7% reported erectile dysfunction, 51.1% hypoactive sexual desire (HSD), 86.7% perceived reduced sleep-related erections (PR-SRE) and 19.1% premature ejaculation. The use of 5ARI was associated with an increased risk of HSD and PR-SR whereas no relationship was found with erectile dysfunction and ejaculation disturbances. Subjects using 5ARI also more frequently had gynecomastia along with reduced SHBG and higher calculated free testosterone levels. All these associations were confirmed in a case-control study comparing 5ARI users with age-body mass index-smoking status and total testosterone-matched controls.

CONCLUSIONS

Our data indicates that use of 5ARI in men with sexual dysfunction does not significantly exacerbate pre-existing ejaculatory or erectile difficulties, but can further impair their sexual life by reducing sexual drive and spontaneous erection.

Testosterone and farnesoid X receptor agonist INT-747 counteract high fat diet-induced bladder alterations in a rabbit model of metabolic syndrome

In the male, metabolic syndrome (MetS) is associated to an increased risk of benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). A recently established rabbit model of high fat diet (HFD)-induced MetS showed hypogonadism and the presence of prostate gland alterations, including inflammation, hypoxia and fibrosis. The present study investigated whether HFD-induced MetS might also alter bladder structure and function. Testosterone and the farnesoid X receptor (FXR) agonist INT-747, were evaluated for possible effects on HFD bladder. MetS rabbits develop bladder alterations, including fibrosis (reduced muscle/fiber ratio), hypoxia [2-fold increase as compared to regular diet (RD) group], low-grade inflammation (increased leukocyte infiltration and inflammatory markers) and RhoA/ROCK hyperactivity. Bladder strips from HFD rabbits, pre-contracted with carbachol, showed an overactive response to the selective ROCK inhibitor Y-27632. All these HFD-induced bladder alterations were partially blunted by testosterone and almost completely reverted by INT-747. Both treatments prevented some MetS features (glucose intolerance and visceral fat increase), thus suggesting that their effects on bladder could be ascribed to an improvement of the metabolic and/or hypogonadal state. However, a pathogenetic role for hypogonadism has been ruled out as GnRH analog-induced hypogonadal rabbits, fed a regular diet, did not show any detectable bladder alterations. In addition, INT-747 did not revert the MetS-induced hypogonadal state. FXR mRNA was highly expressed in rabbit bladder and positively associated with visceral fat increase. A direct effect of INT-747 on bladder smooth muscle was further suggested by inhibition of RhoA/ROCK-mediated activity by in vitro experiments on isolated cells. In conclusion, HFD-related MetS features are associated to bladder derangements, which are ameliorated by testosterone or INT-747 administration. INT-747 showed the most marked effects in counteracting MetS-related RhoA/ROCK overactivity, thus opening novel therapeutic opportunities for this drug.

Urodynamic effects of transrectal intraprostatic Ona botulinum toxin A injections for symptomatic benign prostatic hyperplasia

OBJECTIVE

To investigate urodynamic, symptomatic, and histologic effects of intraprostatic injection with Ona botulinum toxin A for benign prostatic hyperplasia.

METHODS

Patients >55 years with symptomatic benign prostatic hyperplasia failing medical therapy were treated. Inclusion criteria were International Prostate Symptom Score >7, prostate volume 30-50 cm(3), and urodynamic bladder outlet obstruction >Schäfer grade 2. A transrectal intraprostatic injection of 200 IU Ona botulinum toxin A was given. Filling cystometry and pressure flow studies were performed at 3, 6, and 12 months post injection. International Prostate Symptom Score, International Prostate Symptom Score quality of life, prostate-specific antigen, and prostate volume were measured up until 12 months; prostate biopsies before and after Ona botulinum toxin A injection were done for histology and cell proliferation.

RESULTS

Fifteen men (mean age 64.9 years) were included. Ona botulinum toxin A injection was well tolerated with few complications. Postvoid residual improved (170 to 80 mL), but maximum flow rate and bladder outlet resistance parameters did not change during follow-up. International Prostate Symptom Score and International Prostate Symptom Score quality of life improved (22 to 13 and 5 to 2, respectively), whereas prostate-specific antigen and prostate volume remained unaltered. Cell proliferation did not decrease and in 37% and 64% of pre- and posttreatment biopsies, respectively, some degree of prostatitis was found. Ten of 15 patients eventually underwent transurethral prostate resection because of persisting symptoms.

CONCLUSION

Intraprostatic Ona botulinum toxin A for symptomatic benign prostatic hyperplasia did not affect urodynamic outcomes, except for postvoid residual. Although symptom scores improved, we were not able to show change in prostate volume, prostate-specific antigen, or histologic outcomes. A placebo effect of intraprostatic Ona botulinum toxin A could not be ruled out.

The response of the prostate to circulating cholesterol: activating transcription factor 3 (ATF3) as a prominent node in a cholesterol-sensing network

Elevated circulating cholesterol is a systemic risk factor for cardiovascular disease and metabolic syndrome, however the manner in which the normal prostate responds to variations in cholesterol levels is poorly understood. In this study we addressed the molecular and cellular effects of elevated and suppressed levels of circulating cholesterol on the normal prostate. Integrated bioinformatic analysis was performed using DNA microarray data from two experimental formats: (1) ventral prostate from male mice with chronically elevated circulating cholesterol and (2) human prostate cells exposed acutely to cholesterol depletion. A cholesterol-sensitive gene expression network was constructed from these data and the transcription factor ATF3 was identified as a prominent node in the network. Validation experiments confirmed that elevated cholesterol reduced ATF3 expression and enhanced proliferation of prostate cells, while cholesterol depletion increased ATF3 levels and inhibited proliferation. Cholesterol reduction in vivo alleviated dense lymphomononuclear infiltrates in the periprostatic adipose tissue, which were closely associated with nerve tracts and blood vessels. These findings open new perspectives on the role of cholesterol in prostate health, and provide a novel role for ATF3, and associated proteins within a large signaling network, as a cholesterol-sensing mechanism.

Antiinflammatory effect of androgen receptor activation in human benign prostatic hyperplasia cells

Progression of benign prostatic hyperplasia (BPH) involves chronic inflammation and immune dysregulation. Preclinical studies have demonstrated that prostate inflammation and tissue remodeling are exacerbated by hypogonadism and prevented by testosterone supplementation. We now investigated whether, in humans, hypogonadism was associated with more severe BPH inflammation and the in vitro effect of the selective androgen receptor agonist dihydrotestosterone (DHT) on cultures of stromal cells derived from BPH patients (hBPH). Histological analysis of inflammatory infiltrates in prostatectomy specimens from a cohort of BPH patients and correlation with serum testosterone level was performed. Even after adjusting for confounding factors, hypogonadism was associated with a fivefold increased risk of intraprostatic inflammation, which was also more severe than that observed in eugonadal BPH patients. Triggering hBPH cells by inflammatory stimuli (tumor necrosis factor α, lipopolysaccharide, or CD4(+)T cells) induced abundant secretion of inflammatory/growth factors (interleukin 6 (IL6), IL8, and basic fibroblast growth factor (bFGF)). Co-culture of CD4(+)T cells with hBPH cells induced secretion of Th1 inducer (IL12), Th1-recruiting chemokine (interferon γ inducible protein 10, IP10), and Th2 (IL9)- and Th17 (IL17)-specific cytokines. Pretreatment with DHT inhibited NF-κB activation and suppressed secretion of several inflammatory/growth factors, with the most pronounced effects on IL8, IL6, and bFGF. Reduced inflammatory cytokine production by T-cells, an increase in IL10, and a significant reduction of T cells proliferation suggested that DHT exerted a broad anti inflammatory effect on testosterone cells [corrected]. In conclusion, our data demonstrate that DHT exerts an immune regulatory role on human prostatic stromal cells, inhibiting their potential to actively induce and/or sustain autoimmune and inflammatory responses.

The effect of prostate tissue inflammation in benign prostatic hyperplasia on enhancer of zeste homolog 2 ribonucleic acid expression

BACKGROUND AND OBJECTIVES

Enhancer of zeste homolog 2 (EZH2) has been recently found to regulate several genes involved in immunoresponse and autocrine inflammation network. The aim of the study was to quantitate EZH2 messenger ribonucleic acid (mRNA) expression, evaluate its relation to conditions of prostatitis associated with benign prostatic hyperplasia (BPH), and correlate it with the levels of the inflammatory marker interlukin 6 (IL-6).

DESIGN AND SETTING

Cross-sectional study in Middle Eastern men with BPH and prostatitis or BPH only.

PATIENTS AND METHODS

Transrectal ultrasound-guided prostate biopsies were collected from 106 patients suspected of having prostate cancer; however, the histology revealed BPH. Upon further pathological examination, 56 of these cases were identified as BPH with prostatitis and classified as: acute prostatitis (n=13); active chronic prostatitis (n=32); and, chronic inactive prostatitis (n=12). Serum IL-6 levels and EZH2 mRNA expression were measured and compared between patient groups.

RESULTS

EZH2 mRNA was overexpressed in BPH with prostatitis patients compared to BPH only patients (P<.0001). BPH with active chronic prostatitis had higher EZH2 expression than BPH with acute or chronic inactive prostatitis compared to BPH only (P=.05 and .73, respectively). EZH2 mRNA expression showed a negative correlation with IL-6 concentrations in BPH with prostatitis patients (rs=-0.31, P=.02). EZH2 overexpression was associated with an increased risk of having BPH with prostatitis (crude odds ratio 0.20, 95% CI 0.06-0.65, P=.0076).

CONCLUSIONS

EZH2 mRNA expression correlates positively with prostatitis conditions associated with BPH and negatively with serum IL-6 levels. This supports the possible involvement of EZH2 mRNA overexpression in the development of prostate inflammation, and its new regulatory role in suppressing the expression of some inflammatory network genes.

The anti-inflammatory and anti-nociceptive activities of Patrinia villosa and its mechanism on the proinflammatory cytokines of rats with pelvic inflammation

This study explores the anti-inflammatory and anti-nociceptive activities of Patrinia villosa, a Chinese medicinal plant, and to explore its effects on the proinflammatory cytokines of the rats with pelvic inflammation model. The animals were randomly divided into Patrinia villosa group (PV group), dexamethasone group (DEX group), and model-control group (CON group) to perform an ear edema test, a carrageenin-induced paw edema test, a cotton pellet-induced granuloma formation test, and an acetic acid-induced writhing test. The model rats with pelvic inflammation were established, and the serum levels of interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-α) in each group was detected with the Enzyme-Linked ImmunoSorbent Assay (ELISA). The results of the ear edema test, carrageenin-induced paw edema test, cotton pellet-induced granuloma formation test, and acetic acid-induced writhing test all showed that Patrinia villosa had strong anti-inflammatory and anti-nociceptive effects. In the experiment using model rats with pelvic inflammation, we found that the serum levels of IL-6, IL-8 and TNF-α in PV and DEX group were all significantly lower than those of the CON group, and the serum levels of IL-6 and IL-8 in PV group were significantly lower than those of the DEX group. Patrinia villosa, with its strong anti-inflammatory and anti-nociceptive activities, can be used to treat pelvic inflammation and to relieve the associated pain.

Effect of prostatitis on lower urinary tract symptoms: retrospective analysis of prostate biopsy tissue

Purpose

Most patients, even some urologists, assume that prostate volume is the most important prognostic factor for lower urinary tract symptoms (LUTS). In some cases, however, prostatic inflammation is a more important factor in LUTS than is prostate volume. For this reason, comparison of the impact on LUTS of inflammation and prostate volume is an attractive issue.

Materials and Methods

From January 2000 to May 2009, 1,065 men aged between 47 and 91 years (who underwent transrectal ultrasound-guided prostate needle biopsy and transurethral prostatectomy) were retrospectively investigated. Components such as age, serum prostate-specific antigen (PSA) level, prostate volume, and the presence of prostatitis were investigated through independent-sample t-tests, chi-square tests, and univariate and multivariate analyses.

Results

Chi-square tests between prostatitis, prostate volume, serum PSA, and severe LUTS showed that prostate volume (R=0.173; p=0.041) and prostatitis (R=0.148; p<0.001) were related to LUTS. In particular, for a prostate volume under 50 ml, prostatitis was a stronger risk factor than was prostate volume. Among the multivariate predictors, prostatitis (odds ratio [OR]: 1.945; p<0.001) and prostate volume (OR, 1.029; p<0.001) were found to be aggravating factors of LUTS.

Conclusions

For patients with prostate volume less than 50 ml, prostatitis was found to be a more vulnerable factor for LUTS. For those with prostate volume over 50 ml, on the other hand, the volume itself was a more significant risk factor than was prostatitis. In conclusion, the presence of prostatitis is one of the risk factors for LUTS with increased prostate volume.

Testosterone protects from metabolic syndrome-associated prostate inflammation: an experimental study in rabbit

Metabolic syndrome (MetS) and benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS) are often associated. One of their common denominators is hypogonadism. However, testosterone supplementation is limited by concerns for potential prostatic side effects. The objective was to determine whether MetS-associated prostate alterations are prevented by testosterone supplementation. We used a previously described animal model of MetS, obtained by feeding male rabbits a high-fat diet (HFD) for 12 weeks. Subsets of HFD rabbits were treated with testosterone or with the farnesoid X receptor agonist INT-747. Rabbits fed a standard diet were used as controls. HFD-animals develop hypogonadism and all the MetS features: hyperglycemia, glucose intolerance, dyslipidemia, hypertension, and visceral obesity. In addition, HFD-animals show a prostate inflammation. Immunohistochemical analysis demonstrated that HFD-induced prostate fibrosis, hypoxia, and inflammation. The mRNA expression of several proinflammatory (IL8, IL6, IL1β, and TNFα), T lymphocyte (CD4, CD8, Tbet, Gata3, and ROR γt), macrophage (TLR2, TLR4, and STAMP2), neutrophil (lactoferrin), inflammation (COX2 and RAGE), and fibrosis/myofibroblast activation (TGFβ, SM22α, αSMA, RhoA, and ROCK1/ROCK2) markers was significantly increased in HFD prostate. Testosterone, as well as INT-747, treatment prevented some MetS features, although only testosterone normalized all the HFD-induced prostate alterations. Interestingly, the ratio between testosterone and estradiol plasma level retains a significant, negative, association with all the fibrosis and the majority of inflammatory markers analyzed. These data highlight that testosterone protects rabbit prostate from MetS-induced prostatic hypoxia, fibrosis, and inflammation, which can play a role toward the development/progression of BPH/LUTS.

Role of interleukins, IGF and stem cells in BPH

The condition known as benign prostatic hyperplasia may be defined as a benign enlargement of the prostate gland resulting from a proliferation of both benign epithelial and stromal elements. It might also be defined clinically as a constellation of lower urinary tract symptoms (LUTSs) in aging men. The purpose of this review is to consider the ways in which inflammatory cytokines belonging to the interleukin family, members of the IFG family, and stem cells may contribute to the development and progression of BPH-LUTS. This might occur in three mechanisms: One, interleukin signaling, IFG signaling and stem cells may contribute to reactivation of developmental growth mechanisms in the adult prostate leading to tissue growth. Two, given that epidemiologic studies indicate an increased incidence of BPH-LUTS in association with obesity and diabetes, IFG signaling may provide the mechanistic basis for the effect of diabetes and obesity on prostate growth. Three, expression of interleukins in association with inflammation in the prostate may induce sensitization of afferent fibers innervating the prostate and result in increased sensitivity to pain and noxious sensations in the prostate and bladder and heightened sensitivity to bladder filling.

Metabolic syndrome and benign prostatic hyperplasia: evidence of a potential relationship, hypothesized etiology, and prevention

Benign prostatic hyperplasia (BPH) is highly prevalent in older men and causes substantial adverse effects on health. The pathogenesis of this disease is not totally clear. Recent reports have suggested a possible relationship between metabolic syndrome (MetS) and BPH. Single components of MetS (obesity, dyslipidemia, hypertension, and insulin resistance) as well as the syndrome itself may predispose patients to a higher risk of BPH and lower urinary tract symptoms (LUTS). This may stem from changes in insulin resistance, increased autonomic activity, impaired nitrergic innervation, increased Rho kinase activity, pro-inflammatory status, and changes in sex hormones that occur in association with MetS. However, the exact underlying mechanisms that regulate the potential relationship between MetS and BPH/LUTS still need to be clarified. Increased physical activity and dietary strategies may help in decreasing the incidence of MetS and its impact on BPH/LUTS. However, differences in the definitions used to address the examined predictors and endpoints preclude the possibility of arriving at definitive conclusions.

Dedifferentiation of prostate smooth muscle cells in response to bacterial LPS

BACKGROUND

Prostate smooth muscle cells (SMCs) are strongly involved in the development and progression of benign prostatic hyperplasia and prostate cancer. However, their participation in prostatitis has not been completely elucidated. Thus, we aimed to characterize the response of normal SMC to bacterial lipopolysaccharide (LPS).

METHODS

Primary prostate SMCs from normal rats were stimulated with LPS (0.1, 1, or 10 µg/ml) for 24 or 48 hr. The phenotype was evaluated by electron microscopy, immunofluorescence, and Western blot of SMCα-actin (ACTA2), calponin, vimentin, and tenascin-C, while the innate immune response was assessed by immunodetection of TLR4, CD14, and nuclear NF-κB. The secretion of TNFα and IL6 was determined using ELISA.

RESULTS

Bacterial LPS induces SMCs to develop a secretory phenotype including dilated rough endoplasmic reticulum cisternae with well-developed Golgi complexes. Furthermore, SMCs displayed a decrease in ACTA2 and calponin, and an increase in vimentin levels after LPS challenge. The co-expression of ACTA2 and vimentin, together with the induction of tenascin-C expression indicate that a myofibroblastic-like phenotype was induced by the endotoxin. Moreover, LPS elicited a TLR4 increase, with a peak in NF-κB activation occurring after 10 min of treatment. Finally, LPS stimulated the secretion of IL6 and TNFα.

CONCLUSIONS

Prostate SMCs are capable of responding to LPS in vitro by dedifferentiating from a contractile to a miofibroblastic-like phenotype and secreting cytokines, with the TLR4 signaling pathway being involved in this response. In this way, prostate SMCs may contribute to the pathophysiology of inflammatory diseases by modifying the epithelial-stromal interactions.

Androgen regulation of prostate cancer: where are we now?

BACKGROUND

Androgens play an essential role in the development and differentiation of the prostate gland; their contribution to pathological conditions, such as benign prostatic hyperplasia and prostate cancer (PC), remains unclear.

AIM

We reviewed relationships between androgens and the prostate both in physiological and pathological conditions.

MATERIAL AND METHODS

A systematic search of published evidence was performed using Medline (1969 to September 2010).

RESULTS

Androgen-dependency of prostate growth is evident only in the hypogonadal condition, but not in the eugonadal state (the "saturation hypothesis"). There is unequivocal evidence that reducing androgen signaling to the hypogonadal range can reduce PC growth and patient symptoms. At physiological testosterone concentration there is no link between androgen levels and PC risk. In addition, different strategies of androgen deprivation (ADT) for advanced PC are only palliative and rarely cure patients. Preliminary evidence indicates that a low androgen milieu is associated with tumor aggressiveness. Transition to androgen-independence is complex and involves both selection and outgrowth of preexisting androgen resistant clones, as well as adaptative upregulation of genes that help the cancer cells to survive and grow after ADT. Because androgens are essential for the regulation of fat distribution, insulin sensitivity, and lipid and bone metabolism, recent publications have highlighted the concept that ADT may also be involved with an increase in overall, as well as cardiovascular, morbidity and mortality.

CONCLUSIONS

While ADT still represents a cornerstone for the palliative therapy of a small fraction of aggressive PC, a "misuse and/or abuse" of ADT should be avoided.

Tadalafil for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia: pathophysiology and mechanism(s) of action

BACKGROUND

The PDE5 inhibitor tadalafil is investigation for the treatment of lower urinary tract symptoms (LUTS) in men with benign prostatic hyperplasia (BPH). Several clinical studies of tadalafil and other PDE5 inhibitors have reported significant symptom reduction but limited urinary flow rate improvement. This manuscript reviews the published literature describing the pathophysiology of male LUTS, with an emphasis on mechanisms that may be modulated or improved by phosphodiesterase type 5 (PDE5) inhibition.

METHODS

Literature (through March 2010) was obtained via Medline searches and from the individual reviewers files. Articles were selected for review based on describing in vitro, preclinical, or clinical studies of pathological processes contributing to LUTS, or possible effects of PDE5 inhibition in the lower urinary tract.

RESULTS

Major mechanisms contributing to LUTS include: reduced nitric oxide/cyclic guanosine monophosphate signaling; increased RhoA kinase pathway activity; autonomic overactivity; increased bladder afferent activity; and pelvic ischemia. Tadalafil and other PDE5 inhibitors have demonstrated beneficial effects on smooth muscle relaxation, smooth muscle and endothelial cell proliferation, nerve activity, and tissue perfusion that may impact LUTS in men.

CONCLUSIONS

The pathophysiology of male LUTS is complex and not completely understood. LUTS may occur independently of BPH or secondary to BPH but in both cases involve obstructive or irritative mechanisms with substantial pathophysiological overlap. While the precise mechanism remains unclear, inhibition of PDE5 seems to have an effect on several pathways that may impact LUTS.

Comprehensive identification and modified-site mapping of S-nitrosylated targets in prostate epithelial cells

Background

Although overexpression of nitric oxide synthases (NOSs) has been found associated with prostate diseases, the underlying mechanisms for NOS-related prostatic diseases remain unclear. One proposed mechanism is related to the S-nitrosylation of key regulatory proteins in cell-signaling pathways due to elevated levels of NO in the prostate. Thus, our primary objective was to identify S-nitrosylated targets in an immortalized normal prostate epithelial cell line, NPrEC.

Methodology/Principal Findings

We treated NPrEC with nitroso-cysteine and used the biotin switch technique followed by gel-based separation and mass spectrometry protein identification (using the LTQ-Orbitrap) to discover S-nitrosylated (SNO) proteins in the treated cells. In parallel, we adapted a peptide pull-down methodology to locate the site(s) of S-nitrosylation on the protein SNO targets identified by the first technique. This combined approach identified 116 SNO proteins and determined the sites of modification for 82 of them. Over 60% of these proteins belong to four functional groups: cell structure/cell motility/protein trafficking, protein folding/protein response/protein assembly, mRNA splicing/processing/transcriptional regulation, and metabolism. Western blot analysis validated a subset of targets related to disease development (proliferating cell nuclear antigen, maspin, integrin β4, α-catenin, karyopherin [importin] β1, and elongation factor 1A1). We analyzed the SNO sequences for their primary and secondary structures, solvent accessibility, and three-dimensional structural context. We found that about 80% of the SNO sites that can be mapped into resolved structures are buried, of which approximately half have charged amino acids in their three-dimensional neighborhood, and the other half residing within primarily hydrophobic pockets.

Conclusions/Significance

We here identified 116 potential SNO targets and mapped their putative SNO sites in NPrEC. Elucidation of how this post-translational modification alters the function of these proteins should shed light on the role of NO in prostate pathologies. To our knowledge, this is the first report identifying SNO targets in prostate epithelial cells.