Bacteria in the chronic prostatitis-chronic pelvic pain syndrome: molecular approaches to critical research questions

Targeting Ferroptosis Attenuates Inflammation, Fibrosis, and Mast Cell Activation in Chronic Prostatitis

Purpose

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a common urological disorder. Although ferroptosis is closely associated with inflammation, oxidative stress, and neuropathic pain, its role in CP/CPPS has not yet been elucidated. Therefore, we sought to explore the role and mechanism of ferroptosis in the prostatitis development.

Methods

The experimental autoimmune prostatitis (EAP) was established through intradermal immunization of prostate extract. Iron chelator deferoxamine (DFO) and free radical scavenger edaravone (EDA) were applied to evaluate the effects of ferroptosis inhibition on oxidative stress, ferroptosis, inflammation, fibrosis, and mast cell activation in the context of CP/CPPS.

Results

Increased generation of lipid peroxidation products (ROS and MDA) and decreased activities of antioxidant enzymes (SOD and CAT) suggested an aberrant oxidative stress status in EAP model. Elevated iron concentration was observed in the EAP model. Meanwhile, we discovered significant biological performances associated with ferroptosis in CP/CPPS, including the downregulation of the system Xc^-/GPX4 axis and the upregulation of the ACSL4/LPCAT3 axis. EAP rats performed serious leukocyte infiltration, advanced inflammatory grade, and abnormal expression of inflammatory mediators. Abundant collagen deposition, enhanced RhoA, ROCK1, and α-SMA protein levels indicated that EAP rats were prone to suffer from stromal fibrosis compared with control group. An elevated number of degranulated mast cells and corresponding marker TPSB2 represented that mast cell-sensitized pain was amplified in the EAP model. Furthermore, reduction of NRF2/HO-1 indicated a vulnerability of EAP towards ferroptosis response. However, application of DFO and EDA had partially reversed the adverse influences mentioned above.

Conclusion

We first demonstrated that ferroptosis might be a crucial factor of chronic prostatitis progression. Inhibition of ferroptosis using DFO and EDA represented a promising approach for treating prostatitis by ameliorating inflammation, fibrosis, and mast cell activation.

Male Lower Urinary Tract Dysfunction: An Underrepresented Endpoint in Toxicology Research

Lower urinary tract dysfunction (LUTD) is nearly ubiquitous in men of advancing age and exerts substantial physical, mental, social, and financial costs to society. While a large body of research is focused on the molecular, genetic, and epigenetic underpinnings of the disease, little research has been dedicated to the influence of environmental chemicals on disease initiation, progression, or severity. Despite a few recent studies indicating a potential developmental origin of male LUTD linked to chemical exposures in the womb, it remains a grossly understudied endpoint in toxicology research. Therefore, we direct this review to toxicologists who are considering male LUTD as a new aspect of chemical toxicity studies. We focus on the LUTD disease process in men, as well as in the male mouse as a leading research model. To introduce the disease process, we describe the physiology of the male lower urinary tract and the cellular composition of lower urinary tract tissues. We discuss known and suspected mechanisms of male LUTD and examples of environmental chemicals acting through these mechanisms to contribute to LUTD. We also describe mouse models of LUTD and endpoints to diagnose, characterize, and quantify LUTD in men and mice.

Interventions to chronic prostatitis/Chronic pelvic pain syndrome treatment. Where are we standing and what's next?

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a frustrating syndrome. The pathogenesis and state of the art treatment of CP/CPPS are not known. A wide variety of therapies including anti-inflammatories, antibiotics, alpha-blockers, neuropathic pain modulators, and 5α-reductase inhibitors are in practice. These treatment strategies focus on alleviating symptoms in specific domains without treating root-cause and therapeutic outcome is far from satisfactory. We review the literature on current pharmacological treatments for CP/CPPS in detail and suggest future perspectives to modify the treatment strategies. We suggest that introducing novel treatment strategies such as gene editing, and T_regs expressing chimeric receptors may improve the treatment outcomes by inducing immune tolerance and controlling expression of pro-inflammatory cytokines.

Role of gram-positive bacteria in chronic pelvic pain syndrome (CPPS)

INTRODUCTION

Chronic pelvic pain syndrome (CPPS) is a complex disorder that affects a large proportion of all men. A limited understanding of its etiology and pathogenesis is reflected by the absence of effective therapies. Although CPPS is deemed clinically non-infectious with no well-defined etiological role for microbes, bacteria is readily isolated from both healthy and patient prostate secretion and urine samples. Our laboratory has previously demonstrated that a specific gram-negative bacterial isolate can induce CPPS-like symptoms in mice. Here we aimed to expand on these findings examining the role of gram-positive patient-derived bacteria in CPPS.

METHODS

A retrospective analysis of bacterial cultures from CPPS patients from a single center was performed. Gram-positive bacteria were isolated from the expressed prostatic secretion (EPS) of three CPPS-patients (pain inducers, PI) and one from a healthy volunteer (non-pain inducer, NPI). These bacteria were inoculated intra-urethrally in two mouse backgrounds and analyzed for their ability to induce tactile allodynia, voiding dysfunction, and colonize the murine prostate. Host immune responses to bacterial instillation were analyzed by flow cytometry.

RESULTS

PI strains (Staphylococcus haemolyticus 2551, Enterococcus faecalis 427, and Staphylococcus epidermidis 7244) induced and maintained tactile allodynia responses (200% increase above baseline) for 28 days in NOD/ShiLtJ mice. Conversely the healthy subject derived strain (Staphylococcus epidermidis NPI) demonstrated no significant pelvic allodynia induction. Intra-urethral inoculation of the four bacterial strains into C57BL/6 mice did not induce significant increases in pain responses. Infected NOD/ShiLtJ displayed significant voiding dysfunction compared to their control counterparts. Colony counts of prostate tissues from both NOD/ShiLtJ and C57BL/6 mice at day 28 demonstrated that bacterial strains colonized equally well, including NPI. We also determined that mechanistically, the patient-isolates induced prostate inflammation specifically involving T-cells and monocytes.

CONCLUSIONS

Gram-positive isolates from CPPS patients showed enhanced ability to induce tactile allodynia compared to a single taxonomically similar gram-positive strain isolated from a healthy control. Responses were shown to be dependent on host genetic background and not on colonization differences between strains.

Multi-factors including Inflammatory/Immune, Hormones, Tumor-related Proteins and Nutrition associated with Chronic Prostatitis NIH IIIa+b and IV based on FAMHES project

Chronic prostatitis (CP) is a complex disease. Fragmentary evidence suggests that factors such as infection and autoimmunity might be associated with CP. To further elucidate potential risk factors, the current study utilized the Fangchenggang Area Male Health and Examination Survey (FAMHES) project; where 22 inflammatory/immune markers, hormone markers, tumor-related proteins, and nutrition-related variables were investigated. We also performed baseline, regression, discriminant, and receiver operating characteristic (ROC) analyses. According to NIH-Chronic Prostatitis Symptom Index (NIH-CPSI), participants were divided into chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS, pain ≥ 4; divided into IIIa and IIIb sub-groups) and non-CPPS (pain = 0; divided into IV and normal sub-groups). Analyses revealed osteocalcin as a consistent protective factor for CP/CPPS, NIH-IIIb, and NIH-IV prostatitis. Further discriminant analysis revealed that ferritin (p = 0.002) and prostate-specific antigen (PSA) (p = 0.010) were significantly associated with NIH-IIIa and NIH-IV prostatitis, respectively. Moreover, ROC analysis suggested that ferritin was the most valuable independent predictor of NIH-IIIa prostatitis (AUC = 0.639, 95% CI = 0.534–0.745, p = 0.006). Together, our study revealed inflammatory/immune markers [immunoglobulin E, Complement (C3, C4), C-reactive protein, anti-streptolysin, and rheumatoid factors], hormone markers (osteocalcin, testosterone, follicle-stimulating hormone, and insulin), tumor-related proteins (carcinoembryonic and PSA), and a nutrition-related variable (ferritin) were significantly associated with CP or one of its subtypes.

Bacterial Prostatitis: Bacterial Virulence, Clinical Outcomes, and New Directions

Four prostatitis syndromes are recognized clinically: acute bacterial prostatitis, chronic bacterial prostatitis, chronic prostatitis/chronic pelvic pain syndrome, and asymptomatic prostatitis. Because Escherichia coli represents the most common cause of bacterial prostatitis, we investigated the importance of bacterial virulence factors and antimicrobial resistance in E. coli strains causing prostatitis and the potential association of these characteristics with clinical outcomes. A structured literature review revealed that we have limited understanding of the virulence-associated characteristics of E. coli causing acute prostatitis. Therefore, we completed a comprehensive microbiological and molecular investigation of a unique strain collection isolated from healthy young men. We also considered new data from an animal model system suggesting certain E. coli might prove important in the etiology of chronic prostatitis/chronic pelvic pain syndrome. Our human data suggest that E. coli needs multiple pathogenicity-associated traits to overcome anatomic and immune responses in healthy young men without urological risk factors. The phylogenetic background and accumulation of an exceptional repertoire of extraintestinal pathogenic virulence-associated genes indicate that these E. coli strains belong to a highly virulent subset of uropathogenic variants. In contrast, antibiotic resistance confers little added advantage to E. coli strains in these healthy outpatients. Our animal model data also suggest that certain pathogenic E. coli may be important in the etiology of chronic prostatitis/chronic pelvic pain syndrome through mechanisms that are dependent on the host genetic background and the virulence of the bacterial strain.

Updates on therapies for chronic prostatitis/chronic pelvic pain syndrome

Prostatitis comprises of a group of syndromes that affect almost 50% of men at least once in their lifetime and makeup the majority of visits to the Urology Clinics. After much debate, it has been divided into four distinct categories by National Institutes of Health namely (1) acute bacterial prostatitis; (2) chronic bacterial prostatitis; (3) chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) which is further divided into inflammatory and non-inflammatory CP/CPPS; and (4) asymptomatic inflammatory prostatitis. CP/CPPS has been a cause of great concern for both patients and physicians because of the lack of presence of thorough information about the etiological factors along with the difficult-to-treat nature of the syndrome. For the presented manuscript an extensive search on PubMed was conducted for CP/CPPS aimed to present an updated review on the evaluation and treatment options available for patients with CP/CPPS. Several diagnostic criteria’s have been established to diagnose CP/CPPS, with prostatic/pelvic pain for at least 3 mo being the major classifying symptom along with the presence of lower urinary tract symptoms and/or ejaculatory pain. Diagnostic tests can help differentiate CP/CPPS from other syndromes that come under the heading of prostatitis by ruling out active urinary tract infection and/or prostatic infection with uropathogen by performing urine cultures, Meares-Stamey Four Glass Test, Pre- and Post-Massage Two Glass Test. Asymptomatic inflammatory prostatitis is confirmed through prostate biopsy done for elevated serum prostate-specific antigen levels or abnormal digital rectal examination. Researchers have been unable to link a single etiological factor to the pathogenesis of CP/CPPS, instead a cluster of potential etiologies including atypical bacterial or nanobacterial infection, autoimmunity, neurological dysfunction and pelvic floor muscle dysfunction are most commonly implicated. Initially monotherapy with anti-biotics and alpha adrenergic-blockers can be tried, but its success has only been observed in treatment naïve population. Other pharmacotherapies including phytotherapy, neuromodulatory drugs and anti-inflammatories achieved limited success in trials. Complementary and interventional therapies including acupuncture, myofascial trigger point release and pelvic floor biofeedback have been employed. This review points towards the fact that treatment should be tailored individually for patients based on their symptoms. Patients can be stratified phenotypically based on the UPOINT system constituting of Urinary, Psychosocial, Organ-specific, Infectious, Neurologic/Systemic and symptoms of muscular Tenderness and the treatment algorithm should be proposed accordingly. Treatment of CP/CPPS should be aimed towards treating local as well as central factors causing the symptoms. Surgical intervention can cause significant morbidity and should only be reserved for treatment-refractory patients that have previously failed to respond to multiple drug therapies.

Prostatic inflammation enhances basal-to-luminal differentiation and accelerates initiation of prostate cancer with a basal cell origin

Chronic inflammation has been shown to promote the initiation and progression of diverse malignancies by inducing genetic and epigenetic alterations. In this study, we investigate an alternative mechanism through which inflammation promotes the initiation of prostate cancer. Adult murine prostate epithelia are composed predominantly of basal and luminal cells. Previous studies revealed that the two lineages are largely self-sustained when residing in their native microenvironment. To interrogate whether tissue inflammation alters the differentiation program of basal cells, we conducted lineage tracing of basal cells using a K14-CreER;mTmG model in concert with a murine model of prostatitis induced by infection from the uropathogenic bacteria CP9. We show that acute prostatitis causes tissue damage and creates a tissue microenvironment that induces the differentiation of basal cells into luminal cells, an alteration that rarely occurs under normal physiological conditions. Previously we showed that a mouse model with prostate basal cell-specific deletion of Phosphatase and tensin homolog (K14-CreER;Pten(fl/fl)) develops prostate cancer with a long latency, because disease initiation in this model requires and is limited by the differentiation of transformation-resistant basal cells into transformation-competent luminal cells. Here, we show that CP9-induced prostatitis significantly accelerates the initiation of prostatic intraepithelial neoplasia in this model. Our results demonstrate that inflammation results in a tissue microenvironment that alters the normal prostate epithelial cell differentiation program and that through this cellular process inflammation accelerates the initiation of prostate cancer with a basal cell origin.

Eliminating sedimentation for the treatment of chronic pelvic pain syndrome

The aim of this study was to evaluate the curative effects of eliminating sedimentation inside the prostate via manipulation for the treatment of chronic pelvic pain syndrome (CPPS) using the National Institutes of Health (NIH)-chronic prostatitis symptom index (CPSI) scores. According to the prostatitis classification standard of the NIH, 721 patients with CPPS were divided into groups IIIA and IIIB by prostatic fluid routine examination (EPSRt) and treated using manipulation. The treatment was performed once per 3 days for 3–5 min and 10 treatments were considered to be a period. The EPSRt and NIH-CPSI scores were tested before and at the end of each period following treatment. After 3 treatment periods, the effectiveness and total effectiveness rates of the IIIA group were 72.3 and 15.9%, respectively and those of the IIIB group were 71.8 and 16.3%, respectively. Statistical analysis showed no significant differences between the curative effects in the two groups (P>0.05). The NIH-CPSI scores of the two groups were significantly improved following each treatment period (P<0.01). Eliminating sedimentation using manipulation dispersed the blockage, discharged the turbidity and cleared the gland, leading to the elimination of sedimentation and the relief of sinus hyperemia around the prostate, which significantly improved the clinical symptoms of CPPS and the quality of life of the patients.

Th1-Th17 cells contribute to the development of uropathogenic Escherichia coli-induced chronic pelvic pain

The etiology of chronic prostatitis/chronic pelvic pain syndrome in men is unknown but may involve microbes and autoimmune mechanisms. We developed an infection model of chronic pelvic pain in NOD/ShiLtJ (NOD) mice with a clinical Escherichia coli isolate (CP-1) from a patient with chronic pelvic pain. We investigated pain mechanisms in NOD mice and compared it to C57BL/6 (B6) mice, a strain resistant to CP-1-induced pain. Adoptive transfer of CD4+ T cells, but not serum, from CP-1-infected NOD mice was sufficient to induce chronic pelvic pain. CD4+ T cells in CP-1-infected NOD mice expressed IFN-γ and IL-17A but not IL-4, consistent with a Th1/Th17 immune signature. Adoptive transfer of ex-vivo expanded IFN-γ or IL-17A-expressing cells was sufficient to induce pelvic pain in naïve NOD recipients. Pelvic pain was not abolished in NOD-IFN-γ-KO mice but was associated with an enhanced IL-17A immune response to CP1 infection. These findings demonstrate a novel role for Th1 and Th17-mediated adaptive immune mechanisms in chronic pelvic pain.

Prevalence and associated factors for four sexually transmissible microorganisms in middle-aged men receiving general prostate health checkups: a polymerase chain reaction-based study in Korea

PURPOSE

To investigate the prevalence of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Mycoplasma genitalium (MG), and Ureaplasma urealyticum (UU) in first-voided urine samples and to determine the factors associated with positivity for sexually transmissible microorganisms in healthy, middle-aged Korean men.

MATERIALS AND METHODS

Five hundred fifty-one men who came to the hospital for a general prostate health checkup were tested between August 2011 and December 2011. PCR assays for CT, NG, MG, and UU were done with first-voided urine samples and the prevalence of microorganism positivity and association with several clinical parameters were evaluated.

RESULTS

The mean age of the men studied was 50.8±4.7 years. Among the 551 men, 72 (13.1%) had a positive result for at least one microorganism; one (0.2%) had two different species. The overall prevalence of asymptomatic sexually transmitted infections was 11.1% (61/551). The prevalence rates of CT, NG, MG, and UU infection in the general population were 0.4% (2/551), 0.0% (0/551), 1.0% (6/551), and 11.8% (65/551), respectively. CT-positive patients had a lower mean age than did CT-negative patients. There were no significant differences in symptoms by positivity of each microorganism.

CONCLUSIONS

We checked the prevalence rates of four microorganisms, the proportion of symptomatic people, and the association of microbes, age, and symptoms, as the baseline data for Korean middle-aged men. In this population, CT, NG, MG, and UU infections do not seem to be symptomatic. However, the potential role of CT in young men and of UU in middle-aged men with a high rate of detection should be studied continuously as a source of opportunistic infection.

Acute bacterial inflammation of the mouse prostate

BACKGROUND

Prostatic inflammation is gaining increasing attention as a potential etiologic factor in prostate cancer, benign prostatic hyperplasia, lower urinary tract symptoms, and CPPS. This study was performed to address the need for a well characterized model of acute prostatic inflammation that may be used to study the effect of acute inflammation on epithelial and stromal cell proliferation, voiding behavior, and neurovascular physiology.

METHODS

Uropathogenic E. coli 1677 was instilled transurethrally into adult C57BL/6J male mice. Prostates were analyzed at 1, 2, 3, 5, 7, or 14 days post-instillation and compared to saline-instilled and naïve controls. Time course and severity of inflammation were characterized by the quantity and type of inflammatory infiltrate present, hemorrhage, proliferation, and reactive hyperplasia. RT-PCR was performed to characterize inflammatory mediators including IL-1α, IL-1β, IL-1RA, IL-18, IL-6, IL-10, IL-8, TNFα, and COX-2.

RESULTS

Inflammation was evident in all lobes of the prostate with the DLP most severely affected. Infection consistently led to a significant increase in neutrophils and macrophages in the early stages of prostate infection, followed by lymphocytic inflammation at the later time points. Inflammation was accompanied by induction of several inflammatory genes, including IL-1 family members, IL-6, and COX-2, and induced a significant increase in epithelial proliferation and reactive hyperplasia in all three prostate lobes.

CONCLUSIONS

Transurethral inoculation of uropathogenic E. coli 1677 reliably infects the mouse prostate, produces a significant inflammatory response, and induces quantifiable epithelial proliferation and reactive hyperplasia.

Investigating the biological and clinical significance of human dysbioses

Culture-independent microbiological technologies that interrogate complex microbial populations without prior axenic culture, coupled with high-throughput DNA sequencing, have revolutionized the scale, speed and economics of microbial ecological studies. Their application to the medical realm has led to a highly productive merger of clinical, experimental and environmental microbiology. The functional roles played by members of the human microbiota are being actively explored through experimental manipulation of animal model systems and studies of human populations. In concert, these studies have appreciably expanded our understanding of the composition and dynamics of human-associated microbial communities (microbiota). Of note, several human diseases have been linked to alterations in the composition of resident microbial communities, so-called dysbiosis. However, how changes in microbial communities contribute to disease etiology remains poorly defined. Correlation of microbial composition represents integration of only two datasets (phenotype and microbial composition). This article explores strategies for merging the human microbiome data with multiple additional datasets (e.g. host single nucleotide polymorphisms and host gene expression) and for integrating patient-based data with results from experimental animal models to gain deeper understanding of how host-microbe interactions impact disease.

Uropathogenic Escherichia coli induces chronic pelvic pain

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a debilitating syndrome of unknown etiology often postulated, but not proven, to be associated with microbial infection of the prostate gland. We hypothesized that infection of the prostate by clinically relevant uropathogenic Escherichia coli (UPEC) can initiate and establish chronic pain. We utilized an E. coli strain newly isolated from a patient with CP/CPPS (strain CP1) and examined its molecular pathogenesis in cell culture and in a murine model of bacterial prostatitis. We found that CP1 is an atypical isolate distinct from most UPEC in its phylotype and virulence factor profile. CP1 adhered to, invaded, and proliferated within prostate epithelia and colonized the prostate and bladder of NOD and C57BL/6J mice. Using behavioral measures of pelvic pain, we showed that CP1 induced and sustained chronic pelvic pain in NOD mice, an attribute not exhibited by a clinical cystitis strain. Furthermore, pain was observed to persist even after bacterial clearance from genitourinary tissues. CP1 induced pelvic pain behavior exclusively in NOD mice and not in C57BL/6J mice, despite comparable levels of colonization and inflammation. Microbial infections can thus serve as initiating agents for chronic pelvic pain through mechanisms that are dependent on both the virulence of the bacterial strain and the genetic background of the host.

Treatment of chronic prostatitis in Chinese men

The aim of this study is to assess the status of treatment of chronic prostatitis (CP) in Chinese men. A population-based cross-sectional survey was performed, in which 15 000 men aged between 15 and 60 years were randomly selected to receive a questionnaire designed to assess National Institutes of Health Chronic Prostatitis Symptoms Index (NIH-CPSI) status, therapeutic efficacy and 28 other items. A total of 12 743 men (84.95%) completed the questionnaire, of whom 1 071 (8.4%) were identified as having prostatitis-like symptoms and 517 (4.5%) were diagnosed with CP according to NIH-CPSI criteria and prostatitis-like symptomatology. Of the CP patients, 372 (65%) underwent long-term routine treatment 12 times per year. Additionally, 217 (72.8%) patients received antibiotic therapy and 215 (79.3%) men showed therapeutic effects. The treatment cost USD 1 151 (8 059 yuan) per person per year on average. Most CP patients received routine treatment, in most cases with antibiotics. Treatment was costly and most CP patients were not satisfied with its effectiveness. Antibacterial treatment might have been effective primarily in patients with bacterial disease.

Applied chemistry of natural DNA

Recently, natural DNA has emerged as an appealing biomacromolecule for functional materials. It is abundant and renewable, and possesses the well known double helix structure that promises many unique properties difficult to find in other polymers. Natural DNA has been applied in electronic, optical and biomaterials, as a catalyst for enantioselective reactions, and as a material for cleaning the environment. Most of the applications are based on combining DNA with other chemicals or nanoparticles by electrostatic binding, intercalation or groove binding. In this critical review article, recent developments in utilizing natural DNA are reviewed by focusing on three basic properties of DNA: the electrostatic property as a polyelectrolyte, selective affinity for small molecules, and biocompatibility (128 references).

Mechanisms in prostatitis/chronic pelvic pain syndrome

PURPOSE

We reviewed the current literature on mechanisms involved in the pathogenesis of prostatitis/chronic pelvic pain syndrome (CPPS).

MATERIALS AND METHODS

A literature review for the years 1966 to 2003 was performed using the MEDLINE database of the United States National Library of Medicine.

RESULTS

National Institutes of Health categories I and II prostatitis result from identifiable prostatic infections, whereas patients with category IV are asymptomatic. The majority of symptomatic cases are category III or chronic prostatitis (CP)/CPPS. The etiology of CP/CPPS is unknown. The traditional marker of inflammation, namely white blood cells in prostatic fluids, does not correlate with the predominant symptom of pelvic pain. An imbalance toward increased proinflammatory and decreased anti-inflammatory cytokines has been implicated and a few studies have shown some correlation of this with pelvic pain. The imbalance in some men may result from polymorphisms at the cytokine loci. An autoimmune process may be involved and experimental evidence indicates that this can be under hormonal influence. Recent findings include possible defects in the androgen receptor. The prostate may not even be the source of the symptoms. Pelvic pain also correlates with the neurotrophin nerve growth factor implicated in neurogenic inflammation and central sensitization. Finally, psychological stress may produce measurable biochemical changes and influence the other processes. The role of normal prostatic bacterial flora in inciting the inflammatory response has also been reconsidered.

CONCLUSIONS

The symptoms of CP/CPPS appear to result from an interplay between psychological factors and dysfunction in the immune, neurological and endocrine systems.

Autoimmune prostatitis: state of the art

The prostate is one of the main male sex accessory glands and the target of many pathological conditions affecting men of all ages. Pathological conditions of the prostate gland range from infections, chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) of a still unknown aetiology to benign hyperplasia and cancer. CP/CPPS is one of the most prevalent diseases in the urologic clinic and affects men younger than 50 years old. A significant advance in the understanding of CP/CPPS was made when an autoimmune response against prostate antigens was revealed in a considerable number of patients. During the last 30 years, extensive work has been done regarding the development and characterization of different rodent models of experimental autoimmune prostatitis (EAP). It has been demonstrated that tolerance to prostate antigens can be disrupted in some strains of rats and mice and cellular and humoral responses to prostate antigens are elicited. A Th1 pattern has been described and the cellular response seems to be the major pathogenic mechanism involved. Immune cells infiltrate the gland and induce prostate lesions. The genetic background and hormonal imbalance are factors that could contribute to the onset of the disease in susceptible young males. Moreover, spontaneous autoimmune prostatitis could also occur with advanced age in susceptible strains. In this review, we summarize the current knowledge regarding rodent models of EAP and the immunological alterations present in CP/CPPS patients. We also discuss the reliability of these experimental approaches as genuine tools for the study of human disease.

Association between the presence of bacterial 16S RNA in prostate specimens taken during transurethral resection of prostate and subsequent risk of prostate cancer (Sweden)

OBJECTIVE

To study bacterial 16S RNA in archival prostate samples from 352 patients with benign prostate hyperplasia (BPH) and evaluate whether the presence of bacterial DNA was different in those who later developed prostate cancer (n = 171) and in the matched controls that did not progress to cancer (n = 181).

METHODS

16S DNA PCR followed by cloning and sequencing the positive samples.

RESULTS

In 96/352 (27%) of the prostate tissue specimens 16S RNA were detected. Sequence analysis revealed Propionibacterium acnes as the predominant microorganism (23% of 16S RNA positive patients). The second most frequent isolate-Escherichia coli was found in 12 (12%) patients. The other isolates included Pseudomonas sp. (3 patients), Actinomyces sp. (2), Streptococcus mutans (1), Corynebacterium sp. (2), Nocardioides sp. (1), Rhodococcus sp. (1) Veillonella sp. (2). In P. acnes positive samples 62% exhibited severe histological inflammation versus 50% in the bacteria-negative group (p = 0.602). The presence of P. acnes in the prostate was associated with prostate cancer development (OR 2.17, 95% CI 0.77-6.95).

CONCLUSIONS

This study has revealed P. acnes as the most common bacteria in the prostate in BPH. Further studies are needed to clarify its role in contributing to the development of prostatic inflammation and prostate cancer.

Chronic bacterial infection and inflammation incite reactive hyperplasia in a mouse model of chronic prostatitis

BACKGROUND

Chronic inflammation is postulated to contribute to prostate carcinogenesis. We developed a mouse model of chronic prostatitis to test whether infection-induced chronic inflammation would incite reactive changes in prostatic epithelium.

METHODS

Prostate tissues harvested from either phosphate-buffered saline (PBS) or E. coli-infected mice were evaluated for histological changes and immunostained for markers of oxidative stress and epithelial cell proliferation.

RESULTS

As compared to PBS-treated controls, mice infected with E. coli bacteria for 5 days showed foci of uniformly acute inflammation in the glandular lumen and a persistent inflammation at 12 weeks post-inoculation in the stroma. Prostatic glands showing varying degrees of atypical hyperplasia and dysplasia had stronger staining for oxidative DNA damage and increased epithelial cell proliferation than normal prostatic glands.

CONCLUSIONS

These data demonstrate that chronic inflammation induces reactive hyperplasia associated with oxidative stress injury and support the proposed linkage among inflammation, oxidative DNA damage, and prostate carcinogenesis.

Role of bacteria in chronic prostatitis/chronic pelvic pain syndrome

Throughout the past century, we have refined our understanding of prostatitis, moving from using a primarily clinical definition to considering it as a complex inflammatory condition. The inconsistency in identifying uropathogens in patients with symptoms of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) has led to controversy in therapeutic management. There is compelling evidence that the normal prostate has minimal inflammation and no bacteria. Clinicians using the Meares/Stamey criteria identified uropathogens localized to the prostate in only 6% to 8% of CP/CPPS patients. This suggests that bacteria may have a role in less than 10% of men with CP/CPPS. That some patients respond to antimicrobials could suggest that eradication of bacteria reduces symptoms. However, the beneficial effect of antimicrobial drugs may not be due to their antibacterial action, but to their anti-inflammatory action. The normal prostate shows minimal inflammation, but only 50% of CP/CPPS patients exhibit prostatic leukocytosis. Prudence demands that we examine the function of the white blood cells--the cytokines produced. Several basic science advances allowed new avenues of research regarding the detection of molecular evidence of causative uropathogens. New research brings new controversy and unexpected findings, but further refines our understanding of the immune system and the CP/CPPS disease process.

Mouse model for acute bacterial prostatitis in genetically distinct inbred strains

OBJECTIVES

Prostatitis is a common urologic disease seen in adult men. As many as 50% of men will experience an episode of prostatitis in their lifetime, and 2% to 3% of men will have bacterial prostatitis. Because the pathogenic mechanisms of prostatitis remain unclear, we developed a reproducible mouse model of bacterial prostatitis in which to study the etiology and host factors associated with infection susceptibility.

METHODS

Male BALB/c, C3H/HeJ, C3H/HeOuJ, C57BL/6J, and (BALB/c x C3H/HeJ)F1 mice 13 weeks old were inoculated intraurethrally with 2 x 10(6) or 2 x 10(8) Escherichia coli. Control mice were inoculated with phosphate-buffered saline. The animals were killed at 5 days after inoculation to assess the intensities of the bladder and prostate infections.

RESULTS

Significant bladder or prostate infections were not present in the BALB/c, C57BL/6J, or (BALB/c x C3H/HeJ)F1 mice at either inoculum dose. In contrast, both C3H/HeJ and C3H/HeOuJ mice developed high bladder infections and severe, acute prostatitis at both doses. Control mice infected with phosphate-buffered saline had no bladder or prostate infections. The P values were less than 0.01 for the comparison of bladder and prostate colony-forming units between C3H/HeJ or C3H/HeOuJ and BALB/c, C57BL/6J, or F1 mice.

CONCLUSIONS

The strain-dependent differences in susceptibility indicate that genetic factors may play a major role in the etiology of bacterial prostatitis. Because F1 mice did not develop significant bladder and prostate infections, similar to the BALB/c parents, it appears that infection susceptibility is a recessive trait. The availability of this model will allow us to investigate the immunology, genetics, and histopathologic features of bacterial infection of the prostate.

Reduced semen quality in chronic prostatitis patients that have cellular autoimmune response to prostate antigens

BACKGROUND

The relationship between chronic prostatitis and fertility has been controversial for many years. We have previously shown the presence of a cellular autoimmune response against prostate antigens in a group of chronic prostatitis patients. Our main goal was to investigate whether chronic prostatitis (either caused by an infection or an autoimmune response to the prostate gland) could have a deleterious effect on semen quality.

METHODS

Forty-four patients diagnosed as suffering from chronic prostatitis were included and divided into groups according to the presence of infection and/or cellular autoimmune response against prostate antigens. Healthy normal individuals were included as controls. Measurements for sperm concentration, motility, morphology, prostate and seminal vesicle markers, antisperm antibodies, white blood cells and pro-inflammatory cytokines were performed accordingly.

RESULTS

The most severe abnormalities were seen in patients with no evident infection and an autoimmune response against prostate antigens. Moreover, significantly increased levels of pro-inflammatory cytokines were detected in seminal plasma from these patients.

CONCLUSIONS

This study shows that chronic prostatitis patients with cellular autoimmune response to prostate antigens present important alterations in their semen quality parameters. We speculate that an autoimmune response against prostate antigens and the inflammatory process involved may affect male fertility.

An epidemiological study of patients with chronic prostatitis

OBJECTIVE

To assess possible causes, clinical symptoms and improvements in treatment for chronic prostatitis in China.

PATIENTS AND METHODS

The study comprised 3000 patients with chronic prostatitis (aged 20-59 years), selected from urological clinics at province, city and county levels in Anhui (a province in mid-eastern China). Anonymous questionnaires were distributed which included 29 items to ascertain patient age, height, weight, educational background, personality, career, disease course, treatment status, prostatic fluid test and score of the National Institute of Health Chronic Prostatitis Symptom Index (NIH-CPSI).

RESULTS

In all, 2498 valid questionnaires were collected (response rate 83.3%); 78.2% of the patients were aged <40 years and there were fewer patients in groups of increasing age. Discomfort and pain in the pelvis was reported by 52.3%, pain on urination by 23.0%, sexual discomfort by 21.8%, urinary frequency by 65.8%, and voiding discomfort by 74.4%; 34.9% of men were satisfied with their previous treatment.

CONCLUSION

In China there are fewer patients with chronic prostatitis as age increases. The main symptoms were voiding dysfunction, e.g. frequent urination. The prevalence of pain, e.g. on urination, was significantly less than documented in other parts of the world. Most patients had used antibiotics to treat their prostatitis; generally the effect of treating prostatitis was unsatisfactory.

Mechanisms in prostatitis/chronic pelvic pain syndrome

PURPOSE

We reviewed the current literature on mechanisms involved in the pathogenesis of prostatitis/chronic pelvic pain syndrome (CPPS).

MATERIALS AND METHODS

A literature review for the years 1966 to 2003 was performed using the MEDLINE database of the United States National Library of Medicine.

RESULTS

National Institutes of Health categories I and II prostatitis result from identifiable prostatic infections, whereas patients with category IV are asymptomatic. The majority of symptomatic cases are category III or chronic prostatitis (CP)/CPPS. The etiology of CP/CPPS is unknown. The traditional marker of inflammation, namely white blood cells in prostatic fluids, does not correlate with the predominant symptom of pelvic pain. An imbalance toward increased proinflammatory and decreased anti-inflammatory cytokines has been implicated and a few studies have shown some correlation of this with pelvic pain. The imbalance in some men may result from polymorphisms at the cytokine loci. An autoimmune process may be involved and experimental evidence indicates that this can be under hormonal influence. Recent findings include possible defects in the androgen receptor. The prostate may not even be the source of the symptoms. Pelvic pain also correlates with the neurotrophin nerve growth factor implicated in neurogenic inflammation and central sensitization. Finally, psychological stress may produce measurable biochemical changes and influence the other processes. The role of normal prostatic bacterial flora in inciting the inflammatory response has also been reconsidered.

CONCLUSIONS

The symptoms of CP/CPPS appear to result from an interplay between psychological factors and dysfunction in the immune, neurological and endocrine systems.

Acute and chronic prostatitis

In summary, prostatitis is a complex syndrome that spans a spectrum from acute prostatitis with a straightforward presentation to CP-CPPS with a complex array of symptoms. The identification of prostatic or pelvic pain becomes a requirement for the diagnosis of CP-CPPS. The NIH system of prostatitis categorization is a refinement of the traditional classification of prostatitis by Drach et al, which was based on the localization test of Meares and Stamey. The NIH categorization system allows for a framework to define the disease process, and the NIH-CPSI was created to quantify the symptoms of chronic prostatitis. Integral to the classification of prostatitis is the presence or absence of inflammation, determined by looking for leukocytes in the EPS, seminal fluid, and VB3 specimens. In addition, the role of bacteria as a cause in category III prostatitis continues to be debated. Future research into using inflammatory markers (eg, tumor necrosis factor-alpha, interleukin-2) and using PCR to identify the presence of bacteria may further refine the pathophysiology of prostatitis. The mainstream treatment of chronic prostatitis involves antimicrobials, non-steroidal anti-inflammatory medications, and alpha-blockers. The potential role of asymptomatic category IV chronic prostatitis in the etiology of prostate cancer may be delineated further with future research.

Where do we stand with chronic prostatitis? An update

Chronic prostatitis remains a difficult management problem, which reflects the fact that its aetiology remains incompletely understood. It is a common condition that is characterized by protracted symptoms and high morbidity. Although lacking a reliable diagnostic test, antibiotic therapy remains the mainstay of treatment in the majority of cases.

Anaerobic seminal fluid micro-flora in chronic prostatitis/chronic pelvic pain syndrome patients

We investigated the seminal micro-flora of 116 men. Eighty-four men had chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), and 34 of them were also leukocytospermic. Thirty-two asymptomatic men formed the control group. Micro-organisms were found in all of the 116 seminal fluid specimens. More than 20 different micro-organisms were found in both groups. Neisseria gonorrhoeae and Chlamydia trachomatis were not found. A high frequency of anaerobic bacteria was found in all groups (68-79%), and in most of the specimens, anaerobic micro-organisms were equal to or outnumbered the aerobic strains. We found 1-8 different micro-organisms in each semen sample, the total count of micro-organisms ranged from 10(2) to 10(7)/mL of semen. Both parameters were significantly higher in leukocytospermic CP/CPPS (NIH IIIA category) patients (median=5 different micro-organisms; total median count 5 x 10(4)) than in the control group (median=3 different micro-organisms; total median count 10(3)). In the CP/CPPS patients, the prevalence and/or count of some opportunistic bacteria was higher than in the control group. To show that the micro-organisms do not originate from the urethra, first voided urine was also investigated in 17 prostatitis patients and 15 controls. One patient had significantly fewer micro-organisms (median 1 vs. 4) and a lower total count of micro-organisms (median 10(2) vs. 10(4)/mL) in the first-catch urine than in the seminal fluid. We found only one third of the micro-organisms to be similar in urine and semen while anaerobic bacteria and some aerobic opportunists were infrequent in urine. Semen is a suitable specimen for the diagnosis of prostatitis.

Chronic prostatitis

PURPOSE OF REVIEW

This review covers recent developments in the classification, epidemiology, aetiology, diagnosis and treatment of patients diagnosed with chronic prostatitis (NIH classification types II, IIIa/IIIb and IV prostatitis) in the period of review (2001-2002).

RECENT FINDINGS

Recent studies highlight some of the problems with the 1995 NIH classification. Epidemiological studies have confirmed that "prostatitis" is common, with a prevalence of 10-15%. Associations of prostatitis include benign prostatic hyperplasia, sexually transmitted disease, lower urinary tract symptoms, stress, and reduced sunlight exposure. Elevated levels of cytokines in the seminal plasma and prostatic secretions have been detected in men with chronic prostatitis compared with normal individuals, suggesting an active inflammatory process in the male genital tract. This inflammatory reaction may be mediated by an adaptive immune response directed against a genital tract antigen(s) (autoimmunity). Increased levels of bacterial 16S ribosomal DNA in the prostates of men with chronic prostatitis compared with controls are compatible with the notion that a bacterial inflammatory event initiates an auto-immune process; however, the role of bacteria in the continuation of symptoms is unknown.

SUMMARY

The aetiology of chronic pelvic pain syndrome is still not certain, although an auto-immune process is favoured. Further research is required to determine the putative auto-antigen, the immune responses of patients, the role of bacteria in the inflammatory process, and the patients' pain response to genitourinary insults. As yet no diagnostic tests (other than to eliminate other pathology) and few treatments for chronic prostatitis can be recommended on the basis of scientific evidence.