Prostatitis and male infertility

Infertility is a pressing reproductive health issue in modern society, with male factors accounting for approximately 50% of all cases. However, most research on male infertility has primarily focused on the testis, often ignoring the critical role of the prostate. As the largest male reproductive gland, the prostate plays a vital role in semen quality. Prostatic fluid, a major component of semen, significantly influences sperm function and overall male fertility. Prostatitis, the most common prostate disorder among men, particularly with advancing age, can severely impair reproductive health. This article aims to explore the fundamental physiological functions of the prostate, the etiology of prostatitis, and its impact on sperm health. It also discusses potential treatment strategies for prostatitis. Through this review, we hope to deepen understanding of the prostate's crucial role in male infertility.

Insights from bidirectional Mendelian randomization: Evaluating the influence of circulating inflammatory cytokines on prostatitis

Research on prostatitis has primarily focused on inflammatory cytokines in semen or prostatic secretions, with relatively few studies investigating circulating inflammatory cytokines. To explore the relationship between prostatitis and circulating inflammatory cytokines, this study employed bidirectional two-sample Mendelian randomization (MR) to assess the potential associations between prostatitis and 91 circulating inflammatory cytokines. We performed bidirectional MR to explore causal links between 91 circulating inflammatory cytokines and prostatitis. Data were sourced from 14,824 individuals of European ancestry and the Finngen database for prostatitis. The inverse variance-weighted (IVW) method was the primary tool, complemented by MR-Egger, weighted median, weighted mode, and MR-PRESSO to enhance result robustness. Heterogeneity and pleiotropy evaluations were conducted, and GO/KEGG enrichment analyses were used to explore the biological pathways linked to these inflammatory factors and prostatitis. The MR results revealed that Interleukin-10 receptor A (IL-10RA), Natural Killer Cell Receptor 2B4 (CD244), and urokinase-type plasminogen activator (uPA) were identified as risk factors for prostatitis (IVWIL-10RA: OR = 1.242, 95% CI: 1.043-1.478, P = .015; IVWCD244: OR = 1.143, 95% CI: 1.002-1.305, P = .047; IVWuPA: OR = 1.141, 95% CI: 1.009-1.290, P = .035). Conversely, Interleukin-12B (IL-12B) exhibited a protective effect against prostatitis (IVWIL-12B: OR = 0.909, 95% CI: 0.842-0.981, P = .014). Moreover, reverse MR analysis results indicate that prostatitis decreases plasma levels of chemokine (C-C motif) ligand 23 (CCL23), IL-5, and TNF-related activation-induced cytokine (TRANCE) (IVWCCL23: OR = 0.949, 95% CI: 0.906-0.993, P = .025; IVWIL-5: OR = 0.938, 95% CI: 0.890-0.988, P = .016; IVWTRANCE: OR = 0.947, 95% CI: 0.905-0.992, P = .021). This bidirectional MR study identified potential causal links between 7 circulating inflammatory cytokines and prostatitis, offering insights into its pathogenesis and potential targets for future therapies.

Chronic prostatitis/chronic pelvic pain syndrome impairs erectile function by inducing apoptosis in a rat model of experimental autoimmune prostatitis

Over the years, numerous epidemiological studies have shown that chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) promotes erectile dysfunction. Nonetheless, the precise underlying mechanism remains to be fully clarified. The objective of this research was to identify crucial signaling pathways responsible for CP/CPPS-induced erectile dysfunction. Thirty 8-week-old male Sprague‒Dawley rats were randomly assigned to either the CP/CPPS model group or the control group. The CP/CPPS rat model was established through subcutaneous injection of a combination of rat prostate protein and Freund's adjuvant. Penile erectile function assessment was conducted 45 days after immunization through electrical stimulation of the cavernous nerve. RNA sequencing of the corpus cavernosum of the penis was then performed using the Kyoto Encyclopedia of Genes and Genomes and protein‒protein interaction network analysis. Western blotting was performed on the cavernous tissue. Cell apoptosis assays, cell counting kit-8 assays, cell cloning assays, and Western blotting were conducted on rat endothelial cells. Erectile function was significantly lower in the CP/CPPS model group than in the control group (p < 0.001). Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that differentially expressed genes were predominantly enriched in the apoptosis pathway. Moreover, an increase in apoptosis in the rat corpus cavernosum, along with a decrease in the protein expression of CD31 (p = 0.0089) and eNOS (p = 0.0069) following CP/CPPS induction, was observed. In a protein‒protein interaction network, Pitx2 was recognized as a central gene. The role of Pitx2 in regulating apoptosis was demonstrated in experiments using rat endothelial cell lines, and it was found to be regulated by the Wnt/β-catenin pathway. This study highlights the occurrence of cavernous endothelial cell apoptosis in CP/CPPS-induced erectile dysfunction, and the potential mechanism of apoptosis may involve inhibition of the Wnt/β-catenin/Pitx2 pathway.

CD8 T cells are dispensable for experimental autoimmune prostatitis induction and chronic pelvic pain development

Introduction

Chronic Pelvic Pain Syndrome or Chronic Prostatitis (CPPS/CP) is the most prevalent urologic affliction among young adult men. It is a challenging condition to treat, which significantly decreases patient quality of life, mostly because of its still uncertain aetiology. In that regard, an autoimmune origin is a prominent supported theory. Indeed, studies in patients and in rodent models of Experimental Autoimmune Prostatitis (EAP) have provided compelling evidence suggesting a key role of CD4 Th1 cells in disease pathogenesis. However, the implication of other prominent effectors of the immune system, such as CD8 T cells, has yet to be studied.

Methods

We herein analyzed the induction of prostatitis and the development of chronic pelvic pain in EAP using CD8 T cell-deficient animals.

Results

We found similarly elevated PA-specific immune responses, with high frequencies of specific IFNg+CD4+ and IL17+CD4+ T cells in prostate draining lymph nodes from PA-immunized either CD8 KO or wild type animals with respect to controls. Moreover, these peripheral immune responses were paralleled by the development of significant chronic pelvic pain, and accompanied by prostate histological lesions, characterized by hemorrhage, epithelial cell desquamation, marked periglandular leukocyte infiltration, and increased collagen deposition in both, PA-immunized CD8 KO and wild type animals. As expected, control animals did not develop prostate histological lesions.

Discussion

Our results indicate that CD8 T cells do not play a major role in EAP pathogenesis and chronic pelvic pain development. Moreover, our results corroborate the previous notion that a CD4 Th1 associated immune response drives the induction of prostate tissue inflammation and the development of chronic pelvic pain.

Benign prostatic hyperplasia - A novel autoimmune disease with a potential therapy consequence?

Benign prostatic hyperplasia (BPH) is considered as an age-related disease of men with an unknown etiopathophysiology. Chronic inflammation has been proposed as one of the major pathophysiological mechanisms. There is growing evidence for the involvement of autoimmune responses in an inflammatory setting in the prostate. Patients with autoimmune diseases show a significantly elevated prevalence of BPH. Conventional therapy options for BPH are limited, rendering surgery the ultimate alternative. However, immunosuppression via tumor necrosis factor alpha blocker appears to reduce symptoms in patients with BPH and concurrent autoimmune disease due to the reduction of epithelial hyperplasia and macrophage-induced inflammation. New diagnostic options using HEp-2 cells with overexpression of LEDGF/p75 or mitochondrial DNA as autoimmune targets could be used to identify BPH patients with autoimmune responses. Given the presumed involvement of autoimmune responses in BPH and the efficacy of immunosuppression in reducing BPH symptoms, BPH or subvariants of BPH may be candidates for a new autoimmune disease in males.

Genetically elevated bioavailable testosterone level was associated with the occurrence of benign prostatic hyperplasia

BACKGROUND

Recent studies identified several risk factors of benign prostatic hyperplasia (BPH), including dyslipidemia, type 2 diabetes mellitus, hypertension, and obesity. But they were not so reliable and some studies contradicted with one another. Hence, a reliable method is urgently needed to explore exact factors that facilitated BPH development.

METHODS

The study was based on Mendelian randomization (MR) design. All participants were from the most recent genome-wide association studies (GWAS) with large sample size. The causal associations between nine phenotypes (total testosterone level, bioavailable testosterone level, sex hormone-binding globulin, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, type 2 diabetes mellitus, hyper-tension, and body mass index) and BPH outcome were estimated. Two sample MR, bidirectional MR, and multivariate MR (MVMR) were performed.

RESULTS

Increase in bioavailable testosterone level was able to induce BPH based on nearly all combination methods [beta (95% confidence interval (CI)): 0.20 (0.06-0.34) for inverse variance weighted (IVW)]. The other traits seemed to interact with testosterone level and did not cause BPH generally. Higher triglycerides level was likely to raise bioavailable testosterone level [beta (95% CI): 0.04 (0.01-0.06) for IVW]. In MVMR model, bioavailable testosterone level was still associated with BPH occurrence [beta (95% CI) 0.27 (0.03-0.50) for IVW].

CONCLUSIONS

We for the first time validated the central role of bioavailable testosterone level in the pathogenesis of BPH. The complex associations between other traits and BPH should be further investigated.

Resveratrol could attenuate prostatic inflammation in rats with Oestradiol-induced chronic prostatitis

To evaluate the effect of resveratrol in rats with chronic prostatitis, 24 rats were randomly divided into the negative control, vehicle-treated and resveratrol groups. The rats in the vehicle-treated group and the resveratrol group were injected subcutaneously with 17-β-oestradiol (0.25 mg/kg) daily for 6 weeks while the rats in the control group were injected with equivalent normal saline. From the 45th day, the rats in the resveratrol group were given resveratrol (10 mg/kg) by gavage per day while the rest rats were given normal saline. After 55 days, all the rats were sacrificed and the prostatic tissue was removed. Morphological changes were examined by light microscope after H&E staining. The expressions of IL-6, IL-8 and TNF-α were determined through ELISA and immunohistochemical staining. As a result, significant inflammatory cell infiltration and fibroblastic hyperplasia were observed in prostatic stroma in the vehicle-treated group compared with the negative control group, as well as the high expression of IL-6, IL-8 and TNF-α. After resveratrol treatment, inflammatory cell infiltration and fibroblastic hyperplasia were shown prominently reduced. Meanwhile, the expression of IL-6, IL-8 and TNF-α was significantly suppressed. For conclusion, resveratrol could attenuate the prostatic inflammation and downregulate the expression of IL-6, IL-8 and TNF-α in rat with oestradiol-induced chronic prostatitis.

Experimental autoimmune prostatitis: different antigens induction and antigen-specific therapy

PURPOSE

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) has uncertain etiology and lacks effective treatment. Autoimmunity is an important pathogeny, and experimental autoimmune prostatitis (EAP) models have long been used for studying CP/CPPS. This review presents the detailed current knowledge of EAP models based on evaluation criteria aspects to provide a tool for model selection in pathogenesis studies and therapeutic drug screening.

METHODS

We extensively searched the published literature on CP/CPPS and different antigen-induced EAP models focusing on the histopathology, clinical-related phenotypes, and biochemical indicators. We also cover the changes in the prostate function and other organs in EAP. Finally, we try to get some insights about antigen-based therapeutic approaches for CP/CPPS.

RESULTS

Several inciting autoantigens were reported in EAP, including male accessory gland extracts, prostate extracts (PE), prostatic steroid-binding protein, prostatic spermine-binding protein (p25), prostatic acid phosphatase, seminal vesicle secretory protein 2, and T2 peptide. All of these models mimicked histological prostatitis, however only p25- and T2-induced models developed both pelvic pain and voiding behaviors. PE immunization is the most widely used method. Diminished fertility and mental health disorders can be found in PE model. Oral and intravenous T2 peptide have been studied for antigen-specific therapy and achieved preliminary progress in EAP models.

CONCLUSIONS

PE-induced model is the most commonly used, while T2- or p25-model could serve as a promising CP/CPPS model. Antigen-specific therapy in CP/CPPS deserves further study.

T2 Peptide Represents a Major Autoantigen Epitope in Experimental Autoimmune Prostatitis

Chronic prostatitis/chronic pelvic pain syndromes (CP/CPPS) is a clinical tricky problem due to its enigmatic etiology, low cure rate, and high recurrence rate. The research on its pathogenesis has never stopped. In this experimental autoimmune prostatitis (EAP) model, male C57BL/6 mice were subcutaneously immunized with prostate extracts in an adequate adjuvant. For mice in the antibody intervention group, anti-T2 polyclonal antibodies were intraperitoneally injected during the induction of EAP. Animals were periodically monitored for pelvic pain. Hematoxylin and eosin staining was used to assess prostate inflammation. Tumor necrosis factor-α (TNF-α) levels in serum were measured by ELISA kits. The immunized animals developed prostatitis as a consequence of the immune response against prostate antigens. Pelvic pain thresholds were gradually decreased and TNF-α expression significantly increased. T2 plays an important role in the disease since polyclonal antibodies to T2 greatly ameliorated symptoms in animals induced for EAP. T2 peptide may represent the major autoantigen epitope in EAP, which could serve for a better understanding of the etiology of CP/CPPS.

The Anti-Inflammatory and Antioxidative Effects of Ningmitai Capsule in the Experimental Autoimmune Prostatitis Rat Model

Objective

Ningmitai (NMT) capsule has been widely prescribed for the treatment of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), but the mechanism remains unclear. This study aims to evaluate the therapeutic effects of the NMT capsule in the experimental autoimmune prostatitis (EAP) rat models and explore its possible mechanisms.

Methods

A total of fifty male Sprague Dawley rats were used in this study. Prostate extract was obtained for the induction of EAP rat models. The EAP rats were randomly divided into the model group, NMT low-dose group (0.45 g/kg/d), NMT medium-dose group (0.90 g/kg/d), and NMT high-dose group (1.80 g/kg/d), with six rats per group. Three NMT treatment groups were administered with the NMT capsule by gavage for 30 days. HE staining was used for histopathological analyses of prostate tissues. Western blotting was used to measure the expression of proinflammatory factors IL-1β and TNF-α. The MDA level was detected to reflect the level of oxidative stress. The bilateral dorsal root ganglia of T3/L1 to S4 were dissected to measure the substance P expression.

Results

EAP rat models were successfully constructed, in which extensive infiltration of inflammatory cells was found. Treatment of NMT capsule for 30 days and the infiltration of inflammatory cells were significantly mitigated (P < 0.05), especially in the NMT medium-dose group and NMT high-dose group. Moreover, the expression of IL-1β and the level of MDA were significantly decreased (P < 0.05). In addition, NMT treatment could significantly alleviate substance P expression in dorsal root ganglia.

Conclusion

Our findings demonstrate that the NMT capsule can alleviate inflammatory response and oxidative stress and reduce the production of substance P in EAP rats. This provides a theoretical basis for the clinical application of NMT capsule for CP/CPPS treatment.

Search for Novel Diagnostic Biomarkers of Prostate Inflammation-Related Disorders: Role of Transglutaminase Isoforms as Potential Candidates

Investigations on prostate inflammation-related disorders, including acute and chronic prostatitis, chronic pelvic pain syndrome, benign prostate hyperplasia (BPH), and prostate cancer (PCa), are still ongoing to find new, accurate, and noninvasive biomarkers for a differential diagnosis of those pathological conditions sharing some common macroscopic features. Moreover, an ideal biomarker should be useful for risk assessment of prostate inflammation progression to more severe disorders, like BPH or PCa, as well as for monitoring of treatment response and prognosis establishment in carcinoma cases. Recent literature evidence highlighted that changes in the expression of transglutaminases, enzymes that catalyze transamidation reactions leading to posttranslational modifications of soluble proteins, occur in prostate inflammation-related disorders. This review focuses on the role specifically played by transglutaminases 4 (TG4) and 2 (TG2) and suggests that both isoenzymes hold a potential to be included in the list of candidates as novel diagnostic biomarkers for the above-cited prostate pathological conditions.

The relationship between histological prostatitis and lower urinary tract symptoms and sexual function

This prospective analysis assessed the effect of histological prostatitis on lower urinary tract functions and sexual function. The patients were separated into two groups as histologically observed prostatitis (Group A) and no prostatitis (Group B) according to the biopsy outcomes. International prostate symptom score, international index of erectile function-5 scores, maximal and average flow rate, and residual urine volumes were compared statistically between groups. There was no significant difference (P>0.05) in baseline age (t=0.64), body mass index value (t=0.51), prostate volume (t=0.87), prostate-specific antigen levels (t=0.43), maximal (t=0.84) and average flow rate (t=0.59), and post-void residual urine volume (t=0.71). Mean international prostate symptom score in patients with prostatitis was numerically but not significantly higher than that in those without prostatitis (t=0.794, P=0.066). Mean international index of erectile function-5 score in the prostatitis group was significantly lower than that in those without prostatitis (t=1.854, P=0.013). Histological prostatitis notably affected sexual function of patients and may serve as a major risk factor for sexual dysfunction while having little effect on lower urinary tract symptoms.

The role of inflammatory cytokines and ERK1/2 signaling in chronic prostatitis/chronic pelvic pain syndrome with related mental health disorders

Mental health disorders(MHD) in chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) have been widely studied. However, the underlying role of inflammatory cytokines and their associated signaling pathways have not been investigated. Here, we report the potential role of cytokines and associated signaling pathways in CP/CPPS patients with MHD and in a CP/CPPS animal model. CP/CPPS patients (n = 810) and control subjects (n = 992) were enrolled in this case-control multicenter study, and serum cytokine levels were measured. Male Sprague-Dawley rats received multiple intracutaneous injections of an immuno-agent along with a pertussis-diphtheria-tetanus triple vaccine for autoimmune CP/CPPS development. The results revealed that, in CP/CPPS patients with significant MHD, elevated IL-1α, IL-1β, IL-4, IL-13, and TNF-α serum levels were observed. The above five cytokines in CP/CPPS rats were significantly elevated in prostate tissue (p < 0.05), and IL-1β levels were elevated in serum and cerebrospinal fluid. In behavioral tests, CP/CPPS rats showed anxiety- and depression-like symptoms, and impaired spatial and associative memory performance (p < 0.05). In the CP/CPPS group, ERK1/2 phosphorylation levels were increased in the amygdala and nucleus accumbens, and decreased in the hippocampus, but not caudate nucleus. Thus, prostate-derived cytokines, especially IL-1β, cross the blood brain barrier and may lead to enhanced ERK1/2 signaling in several brain areas, possibly underlying induction of CP/CPPS-related MHD.

Influence of E. coli-induced prostatic inflammation on expression of androgen-responsive genes and transforming growth factor beta 1 cascade genes in rats

BACKGROUND

Prostatic inflammation is reportedly associated with the development of prostatic hyperplasia. We investigated the effects of prostatic inflammation on expression levels of androgen-responsive genes and growth factors in the rat prostate.

METHODS

Prostatic inflammation was induced by Escherichia coli (strain 1677) injection (0.2 ml of 1 × 10(8) CFU/ml) into the prostatic urethra of male Sprague-Dawley rats, and ventral lobes of the prostate were harvested on day 84. Rats were given 10 mg/kg celecoxib during the last month in the COX-2 inhibitor treated group. Histopathology and multiplex enzyme-linked immunosorbent assay (ELISA) for inflammation-related proteins were performed. Glandular epithelial cells and stromal regions were separately isolated using laser-capture microdissection (LCM). Real-time RT-PCR was performed to examine mRNA levels of androgen-responsive genes in the epithelium and tumor growth factor-β1 (TGF-β1) cascade genes in the stroma.

RESULTS

Hematoxylin and eosin staining showed that mild inflammation was distributed diffusely throughout the prostate. Polymorphonuclear cells infiltrated the slightly edematous stroma, but no morphological changes were observed in the epithelium. Immunohistochemically, expression of androgen receptor and TGF-β1 in addition to IL-6 and cyclooxigenase-2 (COX-2) were enhanced in the E. coli inoculated rats. All of these factors were suppressed in the celecoxib-treated rats. Upregulation of IL-1α, IL-1β, IL-6, and RANTES in the E. coli-inoculated rats was normalized by celecoxib treatment. Significant upregulation of androgen receptor and androgen-responsive genes such as Eaf2, ELL2, FKBP5, calreticulin, and ornithine decarboxylase was observed in the LCM-dissected epithelium. Also TGF-β1 and its downstream cascade genes such as Hic-5, collagen 1, and fibronectin were upregulated significantly in the LCM-dissected stroma. The COX-2 inhibitor treatment suppressed upregulation of these genes.

CONCLUSIONS

Prostatic inflammation changed the expression of androgen-responsive genes in the epithelium and TGF-β1 cascade genes in the stroma. Activation of TGF-β1 cascade genes in the inflamed stroma, as well as altered androgen-responsive gene expression in the epithelium, might be involved in the development of BPH. Prostate 75:381-389, 2015. © 2014 Wiley Periodicals, Inc.

Histopathological classification criteria of rat model of chronic prostatitis/chronic pelvic pain syndrome

OBJECTIVE

A variety of murine models of experimental prostatitis that mimic the phenotype of human chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) have been developed. However, there is still a lack of explicit diagnosis criteria about those animal model. Our study is to establish histopathological classification criteria, which will be conducive to evaluate the animal models.

METHODS

We firstly established a rat model of experimental autoimmune prostatitis that is considered a valid model for CP/CPPS. For modelling, male Sprague-Dawley rats were immunized with autologous prostate tissue homogenate supernatant emulsified with complete Freund's adjuvant by subcutaneous injection into abdominal flank and simultaneously immunized with pertussis-diphtheria-tetanus vaccine by intraperitoneal injection. Three immunizations were administered semimonthly. At the 45th day, animals were killed, and prostate tissues were examined for morphology.

RESULTS

Histologically, the prostate tissues were characterized by lymphoproliferation, atrophy of acini, and chronic inflammatory cells infiltration in the stromal connective tissue around the acini or ducts. Finally, we built histopathological classification criteria incorporating inflammation locations (mesenchyme, glands, periglandular tissues), ranges (focal, multifocal, diffuse), and grades (grade I-IV). To verify the effectiveness and practicability of the histopathological classification criteria, we conducted the treatment study with one of the alpha blockers, tamsulosin.

CONCLUSION

The histopathological classification criteria of rat model of CP/CPPS will serve for further research of the pathogenesis and treatment strategies of the disease.

Immunotherapy for prostate cancer: lessons from responses to tumor-associated antigens

Prostate cancer (PCa) is the most common cancer in men and the second most common cause of cancer-related death in men. In recent years, novel therapeutic options for PCa have been developed and studied extensively in clinical trials. Sipuleucel-T is the first cell-based immunotherapeutic vaccine for treatment of cancer. This vaccine consists of autologous mononuclear cells stimulated and loaded with an immunostimulatory fusion protein containing the prostate tumor antigen prostate acid posphatase. The choice of antigen might be key for the efficiency of cell-based immunotherapy. Depending on the treatment strategy, target antigens should be immunogenic, abundantly expressed by tumor cells, and preferably functionally important for the tumor to prevent loss of antigen expression. Autoimmune responses have been reported against several antigens expressed in the prostate, indicating that PCa is a suitable target for immunotherapy. In this review, we will discuss PCa antigens that exhibit immunogenic features and/or have been targeted in immunotherapeutic settings with promising results, and we highlight the hurdles and opportunities for cancer immunotherapy.

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.

Strain-specific induction of experimental autoimmune prostatitis (EAP) in mice

BACKGROUND

Prostatitis, a clinical syndrome characterized by pelvic pain and inflammation, is common in adult males. Although several induced and spontaneous murine models of prostatitis have been explored, the role of genetic background on induction has not been well-defined.

METHODS

Using a standard methodology for the induction of experimental autoimmune prostatitis (EAP), we investigated both acute and chronic inflammation on several murine genetic backgrounds.

RESULTS

In our colony, nonobese diabetic (NOD) mice evinced spontaneous prostatitis that was not augmented by immunization with rat prostate extract (RPE). In contrast, the standard laboratory strain Balb/c developed chronic inflammation in response to RPE immunization. Development of EAP in other strains was variable.

CONCLUSIONS

These data suggest that Balb/c mice injected with RPE may provide a useful model for chronic prostatic inflammation.

T cells localized to the androgen-deprived prostate are TH1 and TH17 biased

BACKGROUND

T cells infiltrate the prostates of prostate cancer patients undergoing neoadjuvant androgen deprivation. These prostate-infiltrating T cells have an oligoclonal phenotype, suggesting the development of an antigen-specific T-cell response. We hypothesized that androgen deprivation might elicit a prostate tissue-specific T-cell response that could potentially be combined with other immune-active therapies, and consequently sought to investigate the nature and timing of this T-cell response following castration.

METHODS

We investigated the phenotype and cytokine expression of T cells at various time points in the prostates of Lewis rats following surgical castration, and used adoptive transfer of prostate-infiltrating lymphocytes (PILs) to determine whether the infiltration by T cells was mediated by effects of castration on the prostate or lymphocytes.

RESULTS

Prostate T-cell infiltration shortly after castration was T(H) 1 biased up to approximately 30 days, followed by a predominance of T(H) 17-type cells, which persisted until at least 90 days post castration. PILs from sham-treated or castrate rats localized to the prostates of castrate animals.

CONCLUSIONS

These observations suggest castration elicits a time-dependent prostate-specific T-cell infiltration, and this infiltration is likely mediated by effects of castration on prostate tissue rather than T-cells. These findings have implications for the timing of immunotherapies combined with androgen deprivation as treatments for prostate cancer.

HDAC inhibitor MS-275 attenuates the inflammatory reaction in rat experimental autoimmune prostatitis

BACKGROUND

Experimental autoimmune prostatitis (EAP) is an autoimmune inflammatory disease of male sex accessory glands and is characterized by a cellular and humoral prostate-specific autoimmune response. EAP shares important clinical and immunological features with human chronic prostatitis and chronic pelvic pain syndrome. MS-275, a potent histone deacetylase inhibitor, has promising anti-inflammatory activities and might be a new agent in the therapy of prostate inflammation.

METHODS

EAP rats were treated with MS-275 (5 mg/kg, i.p.) once daily. Using immunohistochemistry and PCR assay, we determined immune cellular responses and infiltration into the prostate glands, and changes of mRNA levels of representative inflammatory molecules in prostate tissue. Changes in Foxp3(+) CD4(+) cell populations of lymph nodes and peripheral blood were analyzed by flow cytometry. Additionally, direct anti-inflammatory effects of MS-275 were investigated in vitro with a macrophage cell line.

RESULTS

MS-275 treatment significantly reduced the local accumulation of immune cells and mRNA levels of representative pro-inflammatory molecules in prostate tissue. Furthermore, MS-275 treatment increased percentage of Foxp3(+) CD4(+) Treg cells in lymph nodes and their proportion to CD4(+) cells in peripheral blood, and induced a relative increase of ED2(+) macrophage numbers in EAP prostate. Additional in vitro study showed that MS-275 induced a switch of macrophages from classic M1 to anti-inflammatory M2 phenotype.

CONCLUSIONS

In summary, our data demonstrated that MS-275 could effectively suppress inflammatory reaction in EAP, through suppressing immune cells and pro-inflammatory molecules, and inducing anti-inflammatory immune cells and molecules, which may suggest MS-275 as a potential candidate for treatment of inflammatory prostatitis.

Elevated body mass index correlates with higher seminal plasma interleukin 8 levels and ultrasonographic abnormalities of the prostate in men attending an andrology clinic for infertility

BACKGROUND

Obesity is associated with a systemic, low-grade inflammatory state. Although the relationship between obesity and semen parameters or prostate diseases has been previously investigated, the association between body mass index (BMI), prostate inflammatory diseases and color- Doppler ultrasound (CDU) of the male genital tract (MGT) has been poorly studied.

AIM

To evaluate the association between BMI and CDU features of the MGT, signs and symptoms of prostate inflammation, semen parameters.

MATERIALS/SUBJECTS AND METHODS

We studied 222 men seeking medical care for couple infertility. According to the World Health Organization classification, subjects were divided into 3 groups: normal weight (no.=131, BMI=18.5-24.9 kg/m2), overweight (no.=71, BMI=25.0-29.9 kg/m2), obese (no.=20, BMI≥30.0 kg/m2). All patients underwent simultaneous testosterone evaluation and seminal analysis, including interleukin 8 (sIL-8), along with scrotal and transrectal CDU, before and after ejaculation. Prostatitis symptoms were evaluated by National Institutes of Health- Chronic Prostatitis Symptom Index questionnaire.

RESULTS

After adjusting for age and testosterone levels, higher BMI was significantly related to higher prostate volume and several CDU features of the prostate, including macro-calcifications, inhomogeneity, higher arterial peak systolic velocity (the latter adjusted also for blood pressure), but not with abnormalities of testis, epididymis, seminal vesicles. Furthermore, higher BMI and BMI class were significantly related to higher sIL-8, a reliable surrogate marker of prostate inflammatory diseases, even after adjustment for age. Conversely, no associations among BMI, clinical symptoms of prostatitis or semen parameters were observed.

CONCLUSIONS

Subjects with higher BMI might develop CDU and biochemical signs suggestive of prostate inflammation, although not clinically overt.

The controversial relationship between benign prostatic hyperplasia and prostate cancer: the role of inflammation

CONTEXT

Prostate cancer (PCa) is the most common cancer in the adult male, and benign prostatic hyperplasia (BPH) represents the most frequent urologic diagnosis in elderly males. Recent data suggest that prostatic inflammation is involved in the pathogenesis and progression of both conditions.

OBJECTIVE

This review aims to evaluate the available evidence on the role of prostatic inflammation as a possible common denominator of BPH and PCa and to discuss its possible clinical implication for the management, prevention, and treatment of both diseases.

EVIDENCE ACQUISITION

The National Library of Medicine Database was searched for the following Patient population, Intervention, Comparison, Outcome (PICO) terms: male, inflammation, benign prostatic hyperplasia, prostate cancer, diagnosis, progression, prognosis, treatment, and prevention. Basic and clinical studies published in the past 10 yr were reviewed. Additional references were obtained from the reference list of full-text manuscripts.

EVIDENCE SYNTHESIS

The histologic signature of chronic inflammation is a common finding in benign and malignant prostate tissue. The inflammatory infiltrates are mainly represented by CD3(+) T lymphocytes (70-80%, mostly CD4), CD19 or CD20 B lymphocytes (10-15%), and macrophages (15%). Bacterial infections, urine reflux, dietary factors, hormones, and autoimmune response have been considered to cause inflammation in the prostate. From a pathophysiologic standpoint, tissue damage associated with inflammatory response and subsequent chronic tissue healing may result in the development of BPH nodules and proliferative inflammatory atrophy (PIA). The loss of glutathione S-transferase P1 (GSTP1) may be responsible in patients with genetic predisposition for the transition of PIA into high-grade intraepithelial neoplasia (HGPIN) and PCa. Although there is growing evidence of the association among inflammatory response, BPH, and PCa, we can only surmise on the immunologic mechanisms involved, and further research is required to better understand the role of prostatic inflammation in the initiation of BPH and PCa. There is not yet proof that targeting prostate inflammation with a pharmacologic agent results in a lower incidence and progression or regression of either BPH or PCa.

CONCLUSIONS

Evidence in the peer-reviewed literature suggested that chronic prostatic inflammation may be involved in the development and progression of chronic prostatic disease, such as BPH and PCa, although there is still no evidence of a causal relation. Inflammation should be considered a new domain in basic and clinical research in patients with BPH and PCa.