Effect of tadalafil on chronic pelvic pain and prostatic inflammation in a rat model of experimental autoimmune prostatitis

NLRP3-mediated IL-1β in regulating the imbalance between Th17 and Treg in experimental autoimmune prostatitis

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a urinary disorder that affects youthful to middle-aged men most frequently. It has been revealed that Th17/Treg imbalance is a crucial factor in the pathophysiological mechanisms behind this disease. However, this imbalance's mechanisms are unknown. In the experimental autoimmune prostatitis (EAP) mouse model, the NLRP3 inflammasome was turned on, IL-1β levels went up. Moreover, there exists a discernible positive association between the upsurge in IL-1β and the perturbation of Th17/Treg equilibrium. Additionally, we have revealed that IL-1β plays a vital role in promoting the differentiation of Naïve CD4+ T cells into the Th17 cells and enhances the conversion of Treg cells into Th17 cells. Further studies revealed that IL-1β promotes STAT3 phosphorylation, which is what causes Treg cells to become Th17 cells. All data strongly suggest that the NLRP3 inflammatory influence Th17 cell development and the conversion of Treg cells into Th17 cells through IL-1β, disrupting the Th17/Treg balance and exacerbating EAP inflammation. In this article, we provide new theories for the pathogenesis of CP/CPPS and propose new prevention and therapy methods.

Extracorporeal Shockwave Therapy Alleviates Inflammatory Pain by Down-Regulating NLRP3 Inflammasome in Experimental Chronic Prostatitis and Chronic Pelvic Pain Syndrome

PURPOSE

To evaluate the anti-inflammatory and antioxidative effects of extracorporeal shockwave therapy (ESWT) on prostatitis and explore the mechanism of alleviating pain.

MATERIALS AND METHODS

For in vitro testing, RWPE-1 cells were randomly divided into 5 groups: (1) RWPE-1 group (normal control), (2) LPS group (lipopolysaccharide inducing inflammation), (3) 0.1ESWT group (treated by 0.1 mJ/mm² energy level), (4) 0.2ESWT group (treated by 0.2 mJ/mm² energy level), and (5) 0.3ESWT group (treated by 0.3 mJ/mm² energy level). After ESWT was administered, cells and supernatant were collected for ELISA and western blot. For in vivo testing, Sprague-Dawley male rats were randomly divided into 3 groups: (1) normal group, (2) prostatitis group, and (3) ESWT group (n=12 for each). Prostatitis was induced by 17 beta-estradiol and dihydrotestosterone (DHT) administration. Four weeks after ESWT, the pain index was assessed for all groups and prostate tissues were collected for immunohistochemistry, immunofluorescence, apoptosis analysis and, western blot.

RESULTS

Our in vitro studies showed that the optimal energy flux density of ESWT was 0.2 mJ/mm². In vivo, ESWT ameliorated discomfort in rats with prostatitis and inflammation symptoms were improved. Compared to normal rats, overexpressed NLRP3 inflammasomes triggered apoptosis in rats with prostatitis and this was improved by ESWT. TLR4-NFκB pathway was overactive after experimental prostatitis, compared to normal and ESWT groups, and prostatitis induced alterations in BAX/BAK pathway were inhibited by ESWT.

CONCLUSIONS

ESWT improved CP/CPPS by reducing NLRP3 inflammasome and ameliorated apoptosis via inhibiting BAX/BAK pathway in a rat model. TLR4 may play a key role in bonding NLRP3 inflammasome and BAX/BAK pathways. ESWT might be a promising approach for the treatment of CP/CPPS.

HA/CD44 Regulates the T Helper 1 Cells Differentiation by Activating Annexin A1/Akt/mTOR Signaling to Drive the Pathogenesis of EAP

CD44 partcipates in multiple inflammatory reactions. Here, we aimed to investigate the role of CD44 and the ligand, hyaluronan (HA), on chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) pathogenesis. We found that CD44 was universally expressed in CD4+ lymphocytes in the peripheral blood of CP/CPPS patients. After silencing CD44 expression or delivering 4-methylumbelliferone (4-MU), the pain severity and prostatic inflammation were significantly relieved. In vitro assay found that HA/CD44 was able to regulate T helper 1 (Th1) cells differentiation, the deficiency of which diminished experimental autoimmune prostatitis (EAP) susceptibility. Bioinformatic analysis suggested that after HA or 4-MU treatment, mTOR signaling was significantly altered, and these results were confirmed by subsequent Western blotting assay. Besides, mass spectrometry and co-immunoprecipitation assays found that CD44 was able to interact with Annexin A1 (ANX A1), and this kind of interaction stabilized ANX A1 protein and maintained the activation of Akt/mTOR pathway. Meanwhile, HA-treatment-enhanced prostatic inflammation, Th1 cell differentiation, and Akt/mTOR pathway activation were reversed after silencing the expression of ANX A1 using shANX A1-lentivirus. The present study systematically investigates the functional role of HA/CD44 in CP/CPPS and identifies novel mechanisms for HA/CD44 promoting Th1 cell differentiation. Targeting the HA/CD44/ANX A1/Akt/mTOR signaling represents novel potential therapeutic strategies for patients with CP/CPPS.

Tissue Kallikrein Protects Rat Prostate against the Inflammatory Damage in a Chronic Autoimmune Prostatitis Model via Restoring Endothelial Function in a Bradykinin Receptor B2-Dependent Way

Objective

The aim of this study was to investigate whether tissue kallikrein (KLK1) can protect the prostate from inflammatory damage and the mechanism involved in it.

Methods

A total of 50 male Wistar rats were used in this study. Initially, 20 rats were sacrificed to obtain the prostate antigen to induce experimental autoimmune prostatitis (EAP), and the remaining 30 rats were randomly divided into 5 experimental groups (normal control group (NC group), NC+KLK1 group (NCK group), EAP group, EAP+KLK1 group (EAPK group), and EAP+KLK1+HOE140 group (EAPKH group); n = 6). It should be explained that KLK1 mainly exerts its biological effects through bradykinin, and HOE140 is a potent and selective bradykinin receptor B2 (BDKRB2) antagonist. EAP was induced by intradermal injection of 15 mg/ml prostate antigen and complete Freund's adjuvant on days 0, 14, and 28. KLK1 was injected via tail vein at a dose of 1.5 × 10⁻³ PAN U/kg once a day, and HOE140 was administered by intraperitoneal injection at 20 μg/kg once every two days. Rats were sacrificed on day 42. The RNA and protein of the rat prostate were extracted to analyze the expression differences of KLK1, as well as the inflammation-, fibrosis-, and oxidative stress-related genes. The inflammatory cell infiltration and microvessel density of the prostate were also analyzed by pathological examination. In addition, pathological analysis was performed on prostate samples from patients undergoing benign prostate hyperplasia (BPH) surgery.

Results

The expression of KLK1 in the prostate decreased in the EAP group as well as BPH patients with obvious inflammation. KLK1 administration significantly inhibited inflammatory cell infiltration and reduced the production of inflammatory cytokines in the EAPK group. Prostate samples from the EAP group showed increased infiltration of T cells and macrophages, as well as gland atrophy, hypoxia, fibrosis, and angiogenesis. KLK1 administration upregulated endothelial nitric oxide synthase (eNOS) expression and suppressed oxidative stress, as well as transforming growth factor β1 (TGF-β) signaling pathways and the proangiogenic vascular endothelial growth factor (VEGF) in the EAPK group. However, in the EAPKH group in which HOE140 blocked BDKRB2, the beneficial effects of KLK1 were all cancelled. In addition, KLK1 intervention in normal rats had no obvious side effects.

Conclusion

The KLK1 expression is inhibited in the inflamed prostates of humans and rats. Exogenous KLK1 restored endothelial function via a BDKRB2-dependent way and then played a role in improving microcirculation and exerted anti-inflammatory, antifibrotic, and antioxidative stress effects in the rat chronic-inflamed prostate.

Association between the presence of bacteria in prostate tissue and histopathology in biopsies from men not complaining of lower urinary tract symptoms

OBJECTIVE

To investigate the presence of bacteria in prostate tissue, and relationships between the bacteria and histopathological findings.

METHODS

Samples were collected from prostate biopsy patients with no obvious lower urinary tract symptoms (LUTS). Detection and identification of bacterial species in the prostate tissues were performed with PCR for 16SrDNA and DNA sequencing. Histopathology was also evaluated. LUTS and lower urinary tract function were assessed by questionnaires, uroflowmetry, and ultrasonography.

RESULTS

DNA was extracted from 97 prostate biopsies, with 5 bacterial species detected among samples from 7 patients (7.2%). The stroma-to-gland ratio in the prostate tissues from patients with bacteria was lower than in those without bacteria (p < 0.01). Glandular epithelial hyperplasia was also identified in the prostates harboring bacteria. International Prostate Symptom Score (IPSS), IPSS-quality of life (IPSS-QOL), Overactive Bladder Symptom Score (OABSS), maximum flow rate, urine volume by uroflowmetry, and post-voided residual urine were not significantly different when comparing patients with and without bacteria in their prostate samples.

CONCLUSIONS

The present study demonstrated that 7.2% of men without obvious LUTS had bacteria in their prostate tissues. The presence of such bacteria might induce glandular hyperplasia and contribute to pathological changes in the early stages of benign prostate enlargement before affecting LUTS.

Melatonin attenuates prostatic inflammation and pelvic pain via Sirt1-dependent inhibition of the NLRP3 inflammasome in an EAP mouse model

BACKGROUND

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a common male genitourinary system disease. As a neuroendocrine hormone, melatonin possesses a variety of biological functions, among which its anti-inflammatory effects have recently drawn substantial attention. The purpose of the current research was to study the effect of melatonin on CP/CPPS and the underlying mechanisms using a mouse model of experimental autoimmune prostatitis (EAP).

METHODS

The EAP mouse model was successfully established by subcutaneously injecting a mixture of prostate antigen and complete Freund's adjuvant. On Day 42, hematoxylin-eosin staining was used to evaluate the histological appearance of prostate tissues. Chronic pelvic pain development was assessed by suprapubic allodynia. The levels of inflammation-related cytokines, such as interferon-γ, interleukin (IL)-17, and IL-1β, were detected by enzyme-linked immunosorbent assay. Then, we explored the anti-inflammatory effects of melatonin on CP/CPPS by Western blotting and immunohistochemical staining, by measuring the expression of silent information regulator 1 (Sirt1) and NLRP3 inflammasome-related proteins in EAP mice.

RESULTS

The EAP model mice exhibited severe diffuse leukocyte infiltration and significantly increased pelvic pain compared to the control mice. In the melatonin treatment group, the histological appearance of the prostate tissues, pelvic pain development, and the levels of proinflammatory cytokines were significantly alleviated compared to the EAP + dimethyl sulfoxide group. Furthermore, we found that the protective effects of melatonin were achieved through activation of the Sirt1 pathway and downregulation of the NLRP3 inflammasome.

CONCLUSIONS

The results indicated that melatonin could attenuate prostate inflammation and pelvic pain by inhibiting the NLRP3 inflammasomes signaling pathway through the activation of Sirt1 in mice with EAP, and these efforts should provide a promising therapeutic strategy for CP/CPPS.

IL-6/STAT3 pathway is involved in the regulation of autophagy in chronic non-bacterial prostatitis cells, and may be affected by the NLRP3 inflammasome

Studies have shown that the cytokine IL-6 plays an important role in the occurrence and development of chronic non-bacterial prostatitis (CNP), but the specific mechanism by which this cytokine regulates CNP is still unclear. At the same time, relevant research have also shown that autophagy is involved in regulating the occurrence and development of inflammation. The possible mechanisms are IL-6/STAT3 signaling pathway and NLRP3 inflammasome. On the basis of establishing the CNP model in rats, we found that IL-6 can regulate autophagy of CNP cells and is associated with the STAT3 pathway and NLRP3 inflammasome. Our results indicate that IL-6 is involved in the regulation of autophagy signaling pathways in CNP. IL-6/STAT3 signaling pathway can suppress cell autophagy pathway in CNP; And the NLRP3 inflammasome may regulate CNP cell autophagy by regulating the IL-6/STAT3 pathway. These findings may provide a new theoretical basis for the pathogenesis of CNP, as well as new ideas and new targets for the treatment and prevention of CNP.

The PDE5 inhibitor udenafil ameliorates nonalcoholic fatty liver disease by improving mitochondrial function

Nonalcoholic fatty liver disease (NAFLD) refers to a series of diseases, including simple steatosis, caused by the excessive accumulation of fat in hepatocytes, nonalcoholic steatohepatitis with inflammation and fibrosis, and more advanced forms of cirrhosis. The pathogenic mechanisms underlying fatty liver and the progression from simple fatty liver to hepatitis and cirrhosis remain unclear. One potentially unifying mechanism may be a dysregulation of free fatty acid oxidation. The oversupply of fatty acids to the liver can result in mitochondrial dysfunction leading to the accumulation of lipids in the liver. Interestingly, there have been several reports showing that inhibitors of phosphodiesterase 5 (PDE5) can increase mitochondrial biogenesis, preserve mitochondrial function in vitro. And, we have recently demonstrated that the phosphodiesterase type 5 inhibitor udenafil improves insulin sensitivity by increasing mitochondrial function in adipocytes. In this study, we aimed to examine the effects of the PDE5 inhibitor udenafil on NAFLD in the ob/ob mouse model. Treatment of ob/ob mice for 6 weeks with udenafil reduced fat mass and fasting glucose. Importantly, udenafil caused a reduction in lipid accumulation in the liver of these mice, including hepatic triglyceride (TG) and cholesterol levels. Mechanistically, udenafil decreased the proinflammatory cytokines in the liver. Also, udenafil increased the levels in the liver of the important lipolytic enzymes and the levels of several mitochondrial β-oxidation related genes. Similar effects were seen in udenafil treated primary hepatocytes. We believe that our study makes a significant contribution to the literature because the results from our study suggest that udenafil may be an effective treatment for NAFLD by improving mitochondrial function.

Effect of Eriocalyxin B on prostatic inflammation and pelvic pain in a mouse model of experimental autoimmune prostatitis

BACKGROUND

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a common disease in males. Eriocalyxin B (EriB), a natural diterpenoid purified from Isodon eriocalyx var. laxiflora, was previously reported to have antitumor effects via multiple immune-related pathways. In this study, we investigated the effect of EriB on CP/CPPS using a mouse model of experimental autoimmune prostatitis (EAP) and explored its potential mechanisms.

METHODS

The EAP model was established in nonobese diabetic mice by intradermal injecting a mixture of prostate antigens and Complete Freund's Adjuvant on days 0 and 28. Then, EAP mice received daily intraperitoneal injections of EriB (5 or 10 mg/kg/d) for 14 days, from days 28 to 42 (EAP+EriB5 or EAP+EriB10 groups). The histopathological appearance of the prostate tissues was evaluated. Chronic pelvic pain development was assessed by cutaneous allodynia. Inflammatory cytokines were measured by enzyme-linked immunosorbent assay tests. We then explored anti-inflammatory potential mechanisms of EriB by studying the effects of PI3K inhibitor wortmannin (EAP+EriB10+Wort group) and NF-κB inhibitor SC75741 (EAP+EriB10+SC group) on prostate inflammation and pelvic pain using this model.

RESULTS

Histological analyses revealed significant prostate inflammation in EAP mice compared with control mice. Significantly increased pelvic pain was detected in EAP mice (P < .05). Compared with the EAP+Veh group, chronic pain development, histological appearance, and cytokine levels demonstrated that EriB could alleviate the severity of EAP in a dose-dependent manner though upregulation of the PI3K/Akt/mTOR pathway and downregulation of the NF-κB pathway. Further mechanism research demonstrated that the PI3K/AKT/mTOR pathway could be blocked by wortmannin, but was not affected by SC75741. In addition, the NF-κB pathway could be further inhibited by SC75741 compared with the EAP+EriB10+Veh group. However, wortmannin could reactivate the NF-κB pathway, indicating that the PI3K/AKT/mTOR pathway negatively regulates the NF-κB pathway during EriB treatment.

CONCLUSIONS

The results of the present study suggested that EriB could alleviate the severity of prostatic inflammation and pelvic pain in an EAP mouse model. These findings may broaden the value of EriB as a promising candidate for the treatment of CP/CPPS.

Aliskiren, tadalafil, and cinnamaldehyde alleviate joint destruction biomarkers; MMP-3 and RANKL; in complete Freund's adjuvant arthritis model: Downregulation of IL-6/JAK2/STAT3 signaling pathway

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease, which is accompanied by progressive joint damage and disability. The intolerability of conventional antirheumatic drugs by some patients necessitates the search for effective antirheumatic agents having better tolerability. In the current work, we aimed to investigate the efficacy of cinnamaldehyde, tadalafil, and aliskiren as potential antirheumatic candidates and to explore their modulatory effects on joint destruction, inflammatory response, and intracellular signaling. Arthritis was induced in female Wistar rats by complete Freund's adjuvant (CFA) 0.4 ml s.c. on days 1, 4, and 7. Treated groups received their respective drugs, starting from day 13, daily for 3 weeks. Methotrexate and prednisolone were the standard antirheumatic drugs, while cinnamaldehyde, tadalafil, and aliskiren were the test agents. Treatment with cinnamaldehyde, tadalafil, or aliskiren reduced serum levels of rheumatoid factor, and pro-inflammatory cytokines; tumor necrosis factor-alpha and interleukin-6 (IL-6), along with elevated level of IL-10 which is an anti-inflammatory cytokine. Besides, cartilage and bone destruction biomarkers; matrix metalloproteinase-3 (MMP-3) and receptor activator of nuclear factor-kappa B ligand (RANKL); were significantly reduced after treatment with the test agents, which was further confirmed by histopathological investigation. The elevated protein expressions of phosphorylated-Janus kinase 2 (p-JAK2), phosphorylated-signal transducer and activator of transcription 3 (p-STAT3), and inducible nitric oxide synthase (iNOS) in articular tissue were markedly attenuated after treatment with cinnamaldehyde, tadalafil, or aliskiren, while that of endothelial nitric oxide synthase (eNOS) was greatly enhanced. In addition, oxidative stress and inflammatory markers such as malondialdehyde, nitric oxide, and myeloperoxidase were reduced in joint tissue after treatment with the test agents, while glutathione content was elevated. Furthermore, the renin inhibitor aliskiren produced effects close to those of the normal and methotrexate, the gold standard antirheumatic drug, in most of the measured parameters.

Collectively, these findings led to the assumption that the downregulation of IL-6/JAK2/STAT3 signaling by cinnamaldehyde, tadalafil, and aliskiren could alleviate joint destruction by MMP-3 and RANKL, reduce iNOS, and enhance eNOS expressions. Moreover, aliskiren could be a promising therapeutic agent for RA, because of its ability to normalize most of the measured parameters after CFA-induced arthritis.

Comparison of cernitin pollen extract vs tadalafil therapy for refractory chronic prostatitis/chronic pelvic pain syndrome: A randomized, prospective study

AIMS

To compare the efficacy of cernitin pollen extract (cernitin) or tadalafil for treating persistent chronic pelvic pain despite α1-blocker monotherapy in men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and lower urinary tract symptoms (LUTS).

METHODS

A total of 100 patients with refractory CP/CPPS despite ongoing α1-blocker monotherapy were randomized to receive add-on therapy with either cernitin (4 capsules/day) or tadalafil (5 mg/d) for 12 weeks. At week 12, changes from baseline in the patients' CP/CPPS, LUTS, and voiding function, as assessed using the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI), the International Prostate Symptom Score (IPSS), and uroflowmetry, respectively, were compared between the groups.

RESULTS

The final analysis included 42 and 45 patients in the cernitin and tadalafil groups, respectively. Although the NIH-CPSI total, NIH-CPSI pain sub-score, and NIH-CPSI quality of life sub-score significantly improved in both groups, the cernitin (vs tadalafil) group showed significantly greater improvements in the NIH-CPSI total score (-6.8 vs -4.6; P = .02) and NIH-CPSI pain sub-score (-4.1 vs -1.5; P < .001). Half (50%) of the patients in the cernitin group showed a reduction greater than 50% in their NIH-CPSI pain sub-score; in the tadalafil group, only four patients (8.9%) showed ≥50% improvement (P < .001). In contrast, the improvement in LUTS was significantly superior in the tadalafil group.

CONCLUSION

Both cernitin and tadalafil significantly ameliorated chronic pelvic pain in patients with refractory CP/CPPS. The add-on of cernitin was more effective than tadalafil for pelvic pain and discomfort.

Phosphodiesterase type 5 inhibitor therapy provides sustained relief of symptoms among patients with chronic pelvic pain syndrome

Background

Chronic prostatitis/chronic pelvic pain syndrome type III (CP/CPPS) is associated with pelvic pain, sexual dysfunction and irritative voiding. Sustained symptom relief has proven difficult with alpha blockers, antibiotics, and nonsteroidal anti-inflammatory drugs (NSAIDs). Phosphodiesterase type 5 (PDE5) inhibitors (PDE5is) have the potential to alleviate bladder urgency, relax the pelvic floor, and correct underlying erectile dysfunction; however, few studies have investigated the application of PDE5i’s to CP/CPPS. The purpose of this study was to assess the effect of long-term PDE5i therapy on symptoms among patients with diagnosed CP/CPPS.

Methods

A group of patients older than 18 years diagnosed with CP/CPPS presenting from 2009 to 2018 were followed prospectively while they were being prescribed off-label PDE5i therapy for symptoms. National Institute of Health chronic prostatitis symptom index (CPSI) scores before PDE5i therapy initiation and after at least 3 months were utilized to assess impact on symptoms.

Results

A total of 25 patients (mean age 44.4±12.9 years) met study criteria. The mean duration of PDE5i therapy was 1.3±1.6 years. Continued use of daily PDE5is was associated with significant decreases in total CPSI, pain, urinary symptom and quality of life scores [total CPSI: −12.8, standard deviation (SD) 9.5; pain: −6.1, SD 4.1; urinary symptoms: −2.4, SD 2.1; quality of life: −4.5, SD 3.9; P<0.001].

Conclusions

This prospective data suggests that PDE5i therapy is associated with durable decreases in CP/CPPS symptoms past 3 months.

Inflammation is a target of medical treatment for lower urinary tract symptoms associated with benign prostatic hyperplasia

Purpose

To review the role of a persistent prostatic inflammatory status (PIS) in the development and progression of benign prostatic hyperplasia (BPH) associated with lower urinary tract symptoms (LUTS) and which medical therapies approved for LUTS/BPH may reduce persistent PIS.

Methods

Literature search in PubMed up to July 2019.

Results

The cause of histologically defined persistent PIS or chronic prostatic inflammation is multifactorial. It is evident in many men with LUTS/BPH, particularly in older men and in men with a large prostate volume or more severe (storage) LUTS. Additionally, persistent PIS is associated with an increased risk of acute urinary retention and symptom worsening. Of medical therapies approved for LUTS/BPH, the current evidence for a reduction of persistent PIS is greatest for the hexanic extract of Serenoa repens (HESr). This treatment relieves LUTS to the same extent as α₁-adrenoceptor antagonists and short-term 5α-reductase inhibitors. Limited evidence is available on the effect of other mainstream LUTS/BPH treatments on persistent PIS.

Conclusions

Persistent PIS plays a central role in both the development and progression of LUTS/BPH. In men with LUTS/BPH who have a high chance of harbouring persistent PIS, HESr will not only improve LUTS, but also reduce (underlying) inflammation. Well-designed clinical studies, with a good level of evidence, are required to better evaluate the impact of BPH/LUTS medical therapies on persistent PIS.

Electronic supplementary material

The online version of this article (10.1007/s00345-020-03106-1) contains supplementary material, which is available to authorized users.

[Experimental rodent models of chronic prostatitis: effect of phosphodiesterase 5 inhibitor on chronic pelvic-pain-related behavior]

Chronic prostatitis / chronic pelvic pain syndrome (CP/CPPS) is commonly diagnosed in men younger than 50 years old. It is characterized by pelvic pain, voiding symptoms and sexual dysfunction. The considerable discomfort or pain experienced has a negative impact on the quality of life of patients and is a huge economic burden because of the high recurrence rate and the low cure rate. Appropriate animal models are essential for the development of new drugs for the treatment of CP/CPPS, and several rodent models induced by different methods and over different time frames have been established. This article reviews studies of three in vivo rodent models of prostatitis, namely, chemical-induced, autoimmune-induced and hormone-associated models reported by us and other investigators. Recent clinical investigation has suggested that tadalafil improves the International Prostatic Symptom Score and the total National Institutes of Health Chronic Prostatitis Symptom Index score of patients with benign prostatic hyperplasia with CP/CPPS, which enables us to investigate the effect of tadalafil on the pelvic-pain-related behavior and prostatic inflammation in two of these prostatitis model types, experimental autoimmune prostatitis (EAP) and hormone/castration-induced prostatitis (HCP). Both models showed the pelvic-pain-related behavior and prostatic inflammation that are characteristic of chronic prostatitis. In EAP, tadalafil suppressed both the pelvic-pain-related behavior and the prostatic inflammation. In HCP, tadalafil suppressed the pelvic-pain-related behavior. These results mimic the clinical findings. Therefore EAP and HCP are suitable for the evaluation of the potency of drugs for the treatment of CP/CPPS.

A phosphodiesterase 5 inhibitor, tadalafil, suppresses stromal predominance and inflammation in a rat model of nonbacterial prostatitis

BACKGROUND

Chronic inflammation is thought to be a major causative factor for the development of benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). Tadalafil, a phosphodiesterase type 5 inhibitor (PDE5-I), which has been used for the treatment of BPH-LUTS in daily practice, is known to act at several urinary organs. In this study, focused on the prostate, we examined the effect of tadalafil on the pathological changes and inflammatory factors in a rat nonbacterial prostatitis (NBP) model.

METHODS

Forty ten-month-old male Wistar rats were divided into nonbacterial prostatitis (NBP), NBP with tadalafil treatment (NBP-tadalafil), control, and control treated with tadalafil (control-tadalafil) groups (n = 10 per group). The NBP and NBP-tadalafil groups were castrated and then received daily subcutaneous 17β-estradiol for 30 days. The control-tadalafil and NBP-tadalafil groups were administered daily oral tadalafil for 30 days. All rats were then sacrificed and pathological changes and inflammatory factors were assessed in the prostatic tissues.

RESULTS

In the NBP group, the stroma-to-epithelium (S/E) ratio in the ventral prostate was significantly higher than in the control group (P < 0.001). In the NBP-tadalafil group, the S/E ratio was significantly lower than in the NBP group (P < 0.001). The macrophage levels and the extent of T-cell infiltration in the NBP-tadalafil group were significantly lower than in the NBP group (P < 0.005; P < 0.001, respectively). Compared with the NBP group, tissue concentrations of inflammatory cytokines, such as tumor necrosis factor-α, interleukin-8, and interleukin-1β, were significantly downregulated in the NBP-tadalafil group (P < 0.01; P < 0.05; P < 0.005, respectively).

CONCLUSIONS

Tadalafil suppressed stromal predominance and showed anti-inflammatory effects in a rat NBP model in association with downregulation of inflammatory cytokines.

Effect of alcohol on chronic pelvic pain and prostatic inflammation in a mouse model of experimental autoimmune prostatitis

BACKGROUND

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a prevalent disease of the urogenital system. Alcohol has been reported to be closely related to CP/CPPS. Thus, we intended to verify the role of alcohol in CP/CPPS and determine the underlying mechanism.

METHODS

We induced experimental autoimmune prostatitis (EAP) mouse model by intradermally injecting a mixture of prostate antigens (PAgs) and complete Freund's adjuvant on days 0 and 28. Mice were treated with alcohol (control-alcohol and EAP-alcohol groups) or vehicle (control-vehicle, and EAP-vehicle groups) from day 32 to 42. Forty-two days after PAg injection, the pathological appearance of the prostate tissues was evaluated, and histological analyses of the prostate were performed. Chronic pelvic pain was assessed by applying von Frey filaments to the lower abdomen. Proinflammatory cytokines were detected by enzyme-linked immunosorbent assay tests. Then, we explored the effects of the NLRP3 inhibitor MCC950 on chronic pelvic pain and prostatic inflammation in this model.

RESULTS

Histological analyses showed diffuse inflammation in the stromal tissues that were characterized by severe infiltration of neutrophils and mononuclear cells in mice in the EAP-alcohol group compared with EAP-vehicle group. Chronic pain tests showed that the response frequency was significantly increased using a von Frey filament at forces of 0.4, 1.0, and 4.0 g in EAP-alcohol group compared with EAP-vehicle (P < .05). The levels of proinflammatory cytokines, including interferon (IFN)-γ, tumor necrosis factor (TNF)-α, IL-17, and IL-1β were all significantly elevated in EAP-alcohol group compared with the EAP-vehicle group (P < .05). However, between the control-alcohol and control-vehicle groups, chronic pain tests, histological assays, and cytokine determinations showed no differences. Furthermore, our results demonstrated that MCC950 could decrease the expression level of NLRP3 inflammasome-related proteins including NLRP3, ASC, and caspase-1. The chronic pain tests, histological assays, and cytokine determinations showed that MCC950 could attenuate the chronic pain and prostatic inflammation through the inhibition of the NLRP3 inflammasome.

CONCLUSIONS

This study indicated that alcohol could aggravate the severity of prostatic inflammation in EAP model though activating the NLRP3 inflammasome. Furthermore, the role of MCC950 in inhibiting NLRP3 inflammasome and decreasing IL-1β secretion to alleviate EAP severity may show that it is a promising therapeutic agent for CP/CPPS.

Benign Prostatic Hyperplasia and Lower Urinary Tract Symptoms: What Is the Role and Significance of Inflammation?

PURPOSE OF REVIEW

The purpose of this review is to summarize the role and significance of inflammation as a putative additional factor contributing to lower urinary tract symptoms and the progression of benign prostatic hyperplasia. We review (1) the histologic definition of prostatic inflammation and its prevalence, (2) the effects inflammation in the prostate including on risk of acute urinary retention, and (3) the effects of systemic inflammation on the prostate and on voiding.

RECENT FINDINGS

Inflammation is a highly prevalent finding in the prostate, both on a histological and biochemical level. Men with inflammation have higher IPSS scores and increased prostate size; however, these differences appear to be imperceptibly small. Men with inflammation do experience a significantly increased risk of developing acute urinary retention, an event that is associated with significant morbidity. Recently, attempts have been made to identify more specific biochemical markers of local inflammation, and to identify regional patterns of inflamed tissue within the prostate which may be associated with higher IPSS scores, accelerated progression, and AUR. The effects of systemic inflammatory states, most notably MetS, and their role in LUTS have also been examined. Inflammation is a common finding in prostates of aging men, but its contribution to lower urinary tract symptoms and benign prostatic hyperplasia progression appears to be small when considered as a clinically relevant entity. Advances in the understanding of different forms of inflammation, and their impact when experienced in different locations within the prostate, may refine this knowledge. Systemic inflammation affects voiding, including in the absence of a prostate, but again significant effects of systemic inflammation on the prostate itself are also difficult to demonstrate. Prostatic inflammation is associated with a significantly increased risk of acute urinary retention.

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.

Voiding behavior and chronic pelvic pain in two types of rat nonbacterial prostatitis models: Attenuation of chronic pelvic pain by repeated administration of tadalafil

BACKGROUND

Experimental autoimmune prostatitis (EAP) and prostatitis induced by 17β-estradiol treatment combined with castration (hormone/castration-induced prostatitis; HCP) are the most commonly used rodent models of nonbacterial prostatitis. We studied the effect of the phosphodiesterase 5 inhibitor tadalafil on chronic pelvic pain in two such models in rats.

METHODS

EAP was induced by intradermal injection of rat prostate antigen and complete Freund's adjuvant on Days 0 and 28. HCP was induced by castration followed by daily subcutaneous injection of 17β-estradiol for 30 days. On Day 42 after antigen injection in the EAP model and Day 30 after castration in the HCP model, we investigated voiding behavior, pelvic pain (measured by applying von Frey filaments to the lower abdomen), and inflammatory changes, including changes in histopathology and IL-1β, CCL2, and CCL3 mRNA levels. We investigated the effect of repeated administration of tadalafil on chronic pelvic pain in both models.

RESULTS

In the EAP model, we observed inflammation in the ventral prostate, while in the HCP model, we observed inflammation in the lateral lobe of the prostate. Neither model showed any change in voiding behavior. As well as in the EAP model, in which chronic pelvic pain was observed, we found for the first time that HCP led to a significant increase in chronic pelvic pain. Repeated treatment with tadalafil attenuated the chronic pelvic pain in both models.

CONCLUSIONS

Chronic pelvic pain was induced in both EAP and HCP models. Tadalafil significantly attenuated the chronic pelvic pain in both models.

Chronic pelvic pain and prostate inflammation in rat experimental autoimmune prostatitis: Effect of a single treatment with phosphodiesterase 5 inhibitors on chronic pelvic pain

BACKGROUND

Experimental autoimmune prostatitis (EAP) is most often used as a nonbacterial model of chronic prostatitis/chronic pelvic pain. We investigated the development of chronic pelvic pain and inflammatory changes in rat EAP and examined the effect of a single treatment with phosphodiesterase 5 (PDE5) inhibitors on the chronic pelvic pain.

METHODS

EAP was induced in rats by intradermal injection of rat prostate antigen and complete Freund's adjuvant on days 0 and 28. On day 42, after antigen injection, prostatic inflammatory changes, including the mRNA and protein levels of cytokines/chemokines, were measured and histological analysis of the prostate was performed. Pelvic pain was measured by applying von Frey filaments to the lower abdomen. To confirm that this model is appropriate for evaluating pelvic pain, we tested two drugs, celecoxib and pregabalin, which are clinically used for the treatment of prostatitis-related pain. Subsequently, we examined the effects of single treatments with three phosphodiesterase 5 inhibitors, including tadalafil, on pelvic pain in this model.

RESULTS

On day 42, after antigen injection, the mRNA levels of 44 of 84 kinds of cytokines/chemokines and their receptors increased significantly in EAP rats, as did the protein levels of seven of 23 kinds of cytokines/chemokines. Histological analysis revealed inflammation characterized by neutrophils and/or mononuclear cells in the glandular and stromal tissue of the ventral prostate from rats in the EAP group. Some animals in this group showed fibrosis and hemorrhage in the stromal tissue. Pelvic pain had developed in EAP rats, which was attenuated by a single treatment with celecoxib or pregabalin, suggesting that EAP is an appropriate model for prostatitis-related pain. A single treatment with any of the three PDE5 inhibitors tested attenuated the chronic pelvic pain.

CONCLUSIONS

Prostatitis leads to inflammatory changes in the prostate, which may contribute to the development and maintenance of chronic pelvic pain. PDE5 inhibitors, including tadalafil, may have the ability to block chronic pelvic pain.

Once-daily 5 mg tadalafil oral treatment for patients with chronic prostatitis/chronic pelvic pain syndrome

Background:

Chronic prostatitis/chronic pelvic pain syndrome (IIIB CP/CPPS) is a condition of unclear aetiology. Many approaches have been used without satisfactory results. The aim of this study is to evaluate the efficacy of once-daily 5 mg tadalafil in pain control and improving quality of life in patients affected by CP/CPPS.

Methods:

Twenty patients affected by chronic prostatitis according EAU (European Association of Urology) guidelines were evaluated for once-daily 5 mg tadalafil; 14 patients were eligible for the study. The validated Italian version of the NIH Chronic Prostatitis Symptom Index (NIH-CPSI) and the International Prostatic Symptom Score (IPSS) questionnaires were submitted to all the patients. Every patient underwent uroflowmetry and ultrasound prostatic volume at the beginning and at the end of the study.

Results:

All 14 patients eligible for the study reported an improvement of symptoms during therapy: statistically significant differences were reported in terms of NIH-CPSI (p < 0.000002) and IPSS (p < 0.0001) during follow-up evaluations. No statistically significant improvement of uroflowmetry parameters was reported during the treatment.

Conclusions:

In our study the daily use of 5 mg tadalafil improves symptoms and quality of life in patients affected by CP/CPPS after 4 weeks of therapy. A larger population of patients is needed to confirm the efficacy of this therapy in CP/CPPS.