Interleukin-18 may lead to benign prostatic hyperplasia via thrombospondin-1 production in prostatic smooth muscle cells

The Effects of Caloric Restriction on Inflammatory Targets in the Prostates of Aged Rats

Numerous animal models have demonstrated that caloric restriction (CR) is an excellent tool to delay aging and increase the quality of life, likely because it counteracts age-induced oxidative stress and inflammation. The aging process can affect the prostate in three ways: the onset of benign prostatic hyperplasia, prostatitis, and prostate cancer. In this study, we used 14 aged male Sprague Dawley rats, which were allocated into two groups, at the age of 18 months old. One group was fed ad libitum (a normal diet (ND)), and the other group followed a caloric restriction diet with a 60% decrease in intake. The rats were sacrificed at the age of 24 months. By immunohistochemical (IHC) and Western blot (WB) analyses, we studied the variations between the two groups in immune inflammation and fibrosis-related markers in aged prostate tissues. Morphological examinations showed lower levels of prostatic hyperplasia and fibrosis in the CR rats vs. the ND rats. The IHC results revealed that the prostates of the CR rats exhibited a lower immune proinflammatory infiltrate level and a reduced expression of the NLRP3 inflammasome pathway, together with significantly reduced expressions of mesenchymal markers and the profibrotic factor TGFβ1. Finally, by WB analysis, we observed a reduced expression of ERα, which is notoriously implicated in prostate stromal proliferation, and increased expressions of SOD1 and Hsp70, both exerting protective effects against oxidative stress. Overall, these data suggest that CR brings potential benefits to prostatic tissues as it reduces the physiological immune-inflammatory processes and the tissue remodeling caused by aging.

Intrinsic and extrinsic factors causing hyperplasia of the prostate

Prostatic hyperplasia is very common in elderly men and is a typical disease that reduces quality of life. Histologically, hyperplasia of the prostate gland causes obstruction at the bladder outlet, resulting in symptoms such as a weak urine stream. Various factors have been considered to cause histological enlargement of the prostate, but the underlying cause is still unknown. The factors that cause prostate hyperplasia can be broadly classified into intrinsic and extrinsic ones. Extrinsic factors include things that we directly come into contact with such as bacteria and food. On the other hand, intrinsic factors are those that cause changes in functions originally provided in the body due to some cause, including extrinsic factors, such as chronic inflammation and an imbalance of sex hormones. A large number of reports have been made to date regarding the etiology of prostatic hyperplasia, although they have not yet clarified the fundamental cause(s). The various factors currently known should be outlined for future research. Should it be possible to prevent this highly prevalent prostatic hyperplasia which is mainly cause of dcreasing quality of life, there is no doubt that it would be a huge contribution to humanity.

Tissue immunoexpression of IL-6 and IL-18 in aging men with BPH and MetS and their relationship with lipid parameters and gut microbiota-derived short chain fatty acids

Recent studies indicate that inflammation is one of the causes of the development of benign prostatic hyperplasia (BPH). Inflammation may result from past infections, metabolic disorders, but also from the state of functioning of the intestinal microbiota. The aim of the study was to assess whether the diagnostic lipid parameters for metabolic syndrome and short-chain fatty acids (SCFAs) are related to the immunoexpression of interleukins in prostate tissue with benign hyperplasia. The study involved 103 men with BPH, who were divided into two groups depending on the presence of MetS. We analysed tissue immunoexpression of two proinflammatory interleukins: IL-6, which is known to be involved in the development of BPH, and IL-18, which has not been analysed so far. The results of our study indicate that men with BPH + MetS in the stroma of the prostate have a significantly higher overall percentage of IL-6+ cells compared to men without MetS (p = 0.034). The analysis of IL-18 immunoexpression in prostate tissue indicated that in men with BPH + MetS, the glandular part of the prostate had a significantly higher percentage of cells with strong IL-18 expression (p = 0.040). We also noticed a relationship between tissue expression of IL-6 and IL-18 and lipid parameters (TG and HDL). We conclude that lipid disorders occurring in men with BPH increase inflammation in the prostate gland. Moreover, it has also been demonstrated for the first time that, indirectly, through SCFAs, the gut microbiota can act to prevent or create an inflammatory microenvironment in the prostate gland.

Association of the inflammatory potential of diet and lower urinary tract symptoms among men in the United States

BACKGROUND

Inflammation is crucial in the pathogenesis of lower urinary tract symptoms (LUTS) in men. Diet modulates inflammation. Therefore, diet could be a modifiable factor in male LUTS prevention and treatment. We aimed to investigate the association between dietary inflammatory potential and male LUTS.

METHODS

We used two cycles of National Health and Nutrition Examination Survey (NHANES) with self-report LUTS data. We calculated the dietary inflammatory index (DII) based on a 24 h diet recall and evaluated male LUTS. Clinical LUTS was defined as two or more coexisting symptoms. We used univariate and multivariate logistic regression models, the smooth curve fitting to analyze the relationship between clinical LUTS and the DII score. Subgroup analyses were conducted.

RESULTS

We observed a positive non-linear relationship between clinical LUTS and DII. We found that when DII was higher than the inflection point 2.39, a 1-unit increase in DII was associated with 26.1% higher adjusted odds of clinical LUTS. Subgroup analyses showed that the DII score was only positively correlated with clinical LUTS risk in non-drinkers, smokers, and non-obese people (DII >2.39).

CONCLUSIONS

Inflammation might be the key mechanism bridging dietary consumption to male LUTS. Excessive pro-inflammatory food intake (DII >2.39) warrants special vigilance, especially for non-drinkers, smokers, and non-obese men.

Serum omentin-1 level in patients with benign prostatic hyperplasia

Backgroud

To evaluate the relationship between omentin-1 and benign prostatic hyperplasia (BPH). BPH is the most common urological disease in elderly men worldwide. Lower serum omentin-1 levels were reported to be negatively associated with the incidence of inflammation, diabetes, obesity and metabolic syndrome, which all play a role in the development of BPH. To the best of our knowledge, the relationship between omentin-1 and BPH has not been investigated previously.

Methods

A total of 70 males participated in this study, including forty patients diagnosed with BPH and thirty healthy males. The anthropometric measurements and the biochemical parameters were measured in this study. We evaluated serum omentin-1 levels and the correlation with those data. We also test the gene expression of IL-8, IL-18 in BPH group using the TURP tissues.

Results

The serum omentin-1 levels were lower in the BPH patients than in the control group (27.95 ± 4.18 versus 32.03 ± 5.46, p < 0.001). The general characteristics and biochemical parameters were investigated, and a negative correlation was found between serum omentin-1 levels and BMI in the BPH group (r = − 0.391, p = 0.013) as well as the whole group (r = − 0.457, p < 0.001). Multiple-factor binary regression analysis revealed that serum omentin-1was a protective factor of BPH development. Furthermore, lower serum omentin-1 levels were associated with higher mRNA expression of IL-8 or IL-18 in the BPH group.

Conclusion

Omentin-1 may suppress the development of BPH and Lower serum omentin-1 levels in BPH patients might associated with higher prostate volume and higher IL-8 and IL-18 expression levels in their prostatic cells.

To protect or adversely affect? The dichotomous role of the NLRP1 inflammasome in human disease

NLRP1 is an inflammasome forming pattern recognition receptor (PRR). When activated by pathogen- and damage- associated molecular patterns (PAMPS/DAMPS), NLRP1 inflammasome formation leads to inflammation through the production of proinflammatory cytokines IL-18 and IL-1β. As with other inflammasome forming NLR family members, NLRP1 also regulates cell death processes, termed pyroptosis. The domain structure of NLRP1 differs between mice and humans, making it possible for the function of the inflammasome to differ between species and adds complexity to the study of this NLR family member. In humans, mutations in both coding and non-coding regions of the NLRP1 gene are linked to a variety of diseases. Likewise, interruption of NLRP1 inhibitors or changes in the prevalence of NLRP1 activators can also impact disease pathobiology. Adding to its complexity, the NLRP1 inflammasome plays a dichotomous role in human diseases, functioning to either attenuate or augment miscellaneous biological processes in a tissue specific manner. For example, NLRP1 plays a protective role in the gastrointestinal tract by modulating the microbiome composition; however, it augments neurological disorders, cardio-pulmonary diseases, and cancer through promoting inflammation. Thus, it is critical that the role of NLRP1 in each of these disease processes be robustly defined. In this review, we summarize the current research landscape to provide a better understanding of the mechanisms associated with NLRP1 function and dysfunction in human disease pathobiology. We propose that a better understanding of these mechanisms will ultimately result in improved insight into immune system dysfunction and therapeutic strategies targeting inflammasome function in multiple human diseases.

Tadalafil Treatment Improves Inflammation, Cognitive Function, And Mismatch Negativity Of Patients With Low Urinary Tract Symptoms And Erectile Dysfunction

Patients with Benign prostatic hyperplasia, low urinary tract symptoms, and erectile dysfunction (BPH/LUTS-ED) present chronic inflammation. We studied in patients with BPH/LUTS-ED the effect of tadalafil treatment (5 mg/day) on changes in peripheral inflammation, cognitive function, and the auditory evoked potential, “mismatch negativity” (MMN). Nine patients with BPH/LUTS-ED and 12 controls performed psychometric tests, MMN. IL-6, IL-17, IL-18, cGMP and CD4⁺CD28⁻ autoreactive T-cells were measured in blood. Patients with BPH/LUTS-ED performed psychometric tests, MMN, and blood extraction at baseline and after tadalafil treatment. Patients with BPH/LUTS-ED showed increased CD4⁺CD28⁻ autoreactive T-cells (p < 0.05), and higher levels of pro-inflammatory interleukins IL-6 (p < 0.001), IL-17 and IL-18 (p < 0.05), compared to controls. Patients got lower scores than controls in psychometric tests assessing mental processing speed and attention (p < 0.05), and showed lower amplitude (p < 0.01) and area (p < 0.05) of MMN wave than controls. Inflammatory, psychometric and electrophysiological parameters were normalized after tadalafil treatment. In conclusion, there is a pro-inflammatory environment in blood in patients with BPH/LUTS-ED which would induce cognitive impairment and alter MMN. Phosphodiesterase-5 inhibition with tadalafil exerts anti-inflammatory effects and ameliorates cognitive function and MMN parameters. Tadalafil could be a promising candidate for chronic treatment in other inflammatory pathologies associated with mild cognitive impairment.

Growth hormone-releasing hormone antagonists reduce prostatic enlargement and inflammation in carrageenan-induced chronic prostatitis

BACKGROUND

Inflammation plays a key role in the etiology of benign prostatic hyperplasia (BPH) through multiple pathways involving the stimulation of proliferation by cytokines and growth factors as well as the induction of the focal occurrence of epithelial-to-mesenchymal transition (EMT). We have previously reported that GHRH acts as a prostatic growth factor in experimental BPH and in autoimmune prostatitis models and its blockade with GHRH antagonists offer therapeutic approaches for these conditions. Our current study was aimed at the investigation of the beneficial effects of GHRH antagonists in λ-carrageenan-induced chronic prostatitis and at probing the downstream molecular pathways that are implicated in GHRH signaling.

METHODS

To demonstrate the complications triggered by recurrent/chronic prostatic inflammation in Sprague-Dawley rats, 50 μL 3% carrageenan was injected into both ventral prostate lobes two times, 3 weeks apart. GHRH antagonist, MIA-690, was administered 5 days after the second intraprostatic injection at 20 μg daily dose for 4 weeks. GHRH-induced signaling events were identified in BPH-1 and in primary prostate epithelial (PrEp) cells at 5, 15, 30, and 60 min with Western blot.

RESULTS

Inflammation induced prostatic enlargement and increased the area of the stromal compartment whereas treatment with the GHRH antagonist significantly reduced these effects. This beneficial activity was consistent with a decrease in prostatic GHRH, inflammatory marker COX-2, growth factor IGF-1 and inflammatory and EMT marker TGF-β1 protein levels and the expression of multiple genes related to EMT. In vitro, GHRH stimulated multiple pathways involved in inflammation and growth in both BPH-1 and PrEp cells including NFκB p65, AKT, ERK1/2, EGFR, STAT3 and increased the levels of TGF-β1 and Snail/Slug. Most interestingly, GHRH also stimulated the transactivation of the IGF receptor.

CONCLUSIONS

The study demonstrates that GHRH antagonists could be beneficial for the treatment of prostatic inflammation and BPH in part by inhibiting the growth-promoting and inflammatory effects of locally produced GHRH.

Inflammatory mediators in the development and progression of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is the most common urological disease in elderly men. Epidemiological data suggest a causal link between this condition and prostatic inflammation. The prostate is an immune-competent organ characterized by the presence of a complex immune system. Several stimuli, including infectious agents, urinary reflux, metabolic syndrome, the ageing process, and autoimmune response, have been described as triggers for the dysregulation of the prostatic immune system via different molecular pathways involving the development of inflammatory infiltrates. From a pathophysiological standpoint, subsequent tissue damage and chronic tissue healing could result in the development of BPH nodules.

Autophagy deactivation is associated with severe prostatic inflammation in patients with lower urinary tract symptoms and benign prostatic hyperplasia

Autophagy is a conserved evolutionary process that allows cells to maintain macromolecular synthesis and energy homeostasis during starvation and stressful conditions. We prospectively evaluated the relationship between autophagy and prostatic inflammation in a series of transurethral prostatic resection samples. Inflammatory infiltrates were defined according to the standardized classification of chronic prostatitis of the National Institute of Health. The inflammatory score (IS score) was calculated. High IS score was defined as ≥7. Each sample was stained for anti-LC3B and for anti-P62/SQSTM1 and scored. High p62 or LC3B percentage was defined as >25%, whereas low was defined as <25% of cells with dots. We analyzed 94 specimens. Overall, 18/94 (19%) showed no sign of prostatic inflammation, whereas 76/94 (81%) presented inflammatory infiltrates. Inflammation was mild in 61/76 (80%), moderate/severe in 15/76 (20%). Patients with high p62 percentage were 62/94 (66%) while 32 (34%) showed low p62 percentage. Patients with high LC3B percentage were 37/94 (39%) while 57(61%) showed low LC3B percentage. Overall 42/94 (44%) patients presented a high p62 percentage and concomitant a low LC3B percentage. IS score was significantly higher in patients with a with high p62 percentage (median IS 7 (6/8) vs 5 (3/7); p= 0.04) and in patients with a low LC3B percentage (median IS 7 (6/8) vs 5 (3/7); p= 0.004) when compared to patients with a low p62 percentage or a high LC3B percentage respectively. On multivariate analysis, p62 (OR: 10.1, 95%CI: 2.6-38.6; p= 0,001) and LC3B expression (OR: 0.319; 95%CI: 0.112-0.907; p= 0.032) were independent predictors of a high IS. Here we present the first evidence of autophagy deregulation in prostatic inflammation. These results raise many questions about the mechanisms mediating the autophagy dysfunction and the links to prostatic inflammation that need to be addressed.

Inflammasomes in the urinary tract: a disease-based review

Inflammasomes are supramolecular structures that sense molecular patterns from pathogenic organisms or damaged cells and trigger an innate immune response, most commonly through production of the proinflammatory cytokines IL-1β and IL-18, but also through less understood mechanisms independent of these cytokines. Great strides have been made in understanding these structures and their dysfunction in various inflammatory diseases, lending new insights into urological and renal problems. From a clinical perspective, benign urinary pathology almost universally involves the inflammatory process, and understanding how inflammasomes translate etiological conditions (diabetes, obstruction, stones, urinary tract infections, etc.) into acute and chronic inflammatory responses is critical to understanding these diseases at a molecular level. To date, inflammasome components have been found in the bladder, prostate, and kidney and have been shown to be activated in response to several infectious and noninfectious insults. In this review, we summarize what is known regarding inflammasomes in both the upper and lower urinary tract and describe several common disease states where they potentially play critical roles.

Inflammasomes are important mediators of prostatic inflammation associated with BPH

Background

There is mounting evidence to support the role of inflammation in benign prostate hyperplasia (BPH), and a recent study reported expression of inflammasome derived cytokine IL-18 in prostate biopsy of BPH patients. Here we examined the expression of inflammasome-derived cytokines and activation of nucleotide-binding oligomerization domain-like receptor with pyrin domain protein 1 (NLRP) 1 inflammasome in a rat model of prostatic inflammation relevant to BPH.

Methods

Prostatic inflammation was experimentally induced in three-month-old male Sprague–Dawley rats by intraprostatic injection (50 μL) of either 5 % formalin or saline (sham) into the ventral lobes of prostate. 7 days later, prostate and bladder tissue was harvested for analysis of inflammasome by Western blot, immunohistochemistry and downstream cytokine production by Milliplex.

Results

Expression of interleukins, CXC and CC chemokines were elevated 2-15 fold in formalin injected prostate relative to sham. Significant expression of NLRP1 inflammasome components and caspase-1 in prostate were associated with significant elevation of pro and cleaved forms of IL-1β (25.50 ± 1.16 vs 3.05 ± 0.65 pg/mg of protein) and IL-18 (1646.15 ± 182.61 vs 304.67 ± 103.95 pg/mg of protein). Relative to prostate tissue, the cytokine expression in bladder tissue was much lower and did not involve inflammasome activation.

Conclusions

Significant upregulation of NLRP1, caspase-1 and downstream cytokines (IL-18 and IL-1β) suggests that a NLRP1 inflammasome is assembled and activated in prostate tissue of this rat model. Recapitulation of findings from human BPH specimens suggests that the inflammasome may perpetuate the inflammatory state associated with BPH. Further clarification of these pathways may offer innovative therapeutic targets for BPH-related inflammation.