Uric acid: a modulator of prostate cells and activin sensitivity

Inhibin subunit beta B (INHBB): an emerging role in tumor progression

The gene inhibin subunit beta B (INHBB) encodes the inhibin βB subunit, which is involved in forming protein members of the transforming growth factor-β (TGF-β) superfamily. The TGF-β superfamily is extensively involved in cell proliferation, differentiation, adhesion, movement, metabolism, communication, and death. Activins and inhibins, which belong to the TGF-β superfamily, were first discovered in ovarian follicular fluid. They were initially described as regulators of pituitary follicle-stimulating hormone (FSH) secretion both in vivo and in vitro. Later studies found that INHBB is expressed not only in reproductive organs such as the ovary, uterus, and testis but also in numerous other organs, including the brain, spinal cord, liver, kidneys, and adrenal glands. This wide distribution implies its involvement in the normal physiological functions of various organs; however, the mechanisms underlying these functions have not yet been fully elucidated. Recent studies suggest that INHBB plays a significant, yet complex role in tumorigenesis. It appears to have dual effects, promoting tumor progression in some contexts while inhibiting it in others, although these roles are not yet fully understood. In this paper, we review the different expression patterns, functions, and mechanisms of INHBB in normal and tumor tissues to illustrate the research prospects of INHBB in tumor progression.

Allopurinol and prostate cancer survival in a Finnish population-based cohort

BACKGROUND

Allopurinol is gout medication that inhibits uric acid formation. Its possible anti-carcinogenic properties have been under research in past years. Studies based on Taiwanese registries showed that long term allopurinol use might reduce prostate cancer (PCa) incidence. However, our studies based on Finnish registries did not support those findings. In this study, we evaluate whether allopurinol use is associated with prostate cancer-specific survival (CSS) or overall survival (OS) in a Finnish population-based cohort.

METHODS

The study cohort was originally enrolled for the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC). We included all newly diagnosed PCa cases during 1996-2015, 9252 men in total. Information on allopurinol purchases was from the national prescription registry of the Social Insurance Institution of Finland. Information about deaths, treatments, and use of other medications was obtained from registries, and tumor stage and PSA at diagnosis from medical records. Follow-up started at diagnosis, and we analysed separately two endpoints: PCa-specific death and overall death. We used an extended Cox regression with adjustment for age at diagnosis, Charlson comorbidity index, FinRSPC trial arm, use of other drugs and EAU PCa risk group.

RESULTS

During a median follow-up of 9.86 years, 2942 deaths occurred, including 883 from PCa. There was no difference in CSS between allopurinol user and non-users, but allopurinol users had lower OS (multivariable-adjusted hazard ratio 1.77; 95% CI: 1.57-2.00). However, this decrease in OS was mitigated along with increasing intensity of allopurinol use.

CONCLUSIONS

We found no marked difference in CSS by allopurinol use. Allopurinol users had lower OS but there were no significant differences by duration or intensity of allopurinol use. Allopurinol use may not have anticancer effects against prostate cancer; instead, it may be a surrogate for metabolic problems causing shorter OS among men with PCa.

Targeting benign prostate hyperplasia treatments: AR/TGF-β/NOX4 inhibition by apocynin suppresses inflammation and proliferation

INTRODUCTION

Apocynin (Apo), an NADPH oxidase (NOX) inhibitor, has been widely used to treat various inflammatory diseases. However, the therapeutic effects of Apo on benign prostatic hyperplasia (BPH), a multifactorial disease associated with chronic inflammation and hormone imbalance, remain unknown.

OBJECTIVES

The link between androgen signaling, reactive oxygen species (ROS), and prostate cell proliferation may contribute to the pathogenesis of BPH; therefore, the aim of this study was to identify the specific signaling pathway involved and to demonstrate whether the anti-oxidant Apo plays a role in the prevention and treatment of BPH.

METHODS

Ingenuity pathway analysis and si-RNA transfection were conducted to demonstrate the androgen receptor (AR) and NOX4 linkage in BPH. Pathological markers of BPH were measured by H&E staining, immunoblotting, ELISA, qRT-PCR, and immunofluorescence to examine the effect of Apo. Rats stimulated with testosterone and BPH-1 cells were used as BPH models.

RESULTS

AR and NOX4 network-mediated oxidative stress was upregulated in the BPH model. Next, we examined the effects of Apo on oxidative stress and chronic prostatic inflammation in BPH mouse models. In a testosterone-induced BPH rat model, Apo alleviated pathological prostate enlargement and suppressed androgen/AR signaling. Apo suppressed the upregulation of proinflammatory markers and promoted the expression of anti-oxidant factors. Furthermore, Apo regulated the TGF-β/Glut9/activin pathway and macrophage programming. In BPH-1 cells, Apo suppressed AR-mediated proliferation and upregulation of TGFB and NOX4 expression by alleviating oxidative stress. Apo activated anti-oxidant and anti-inflammatory systems and regulated macrophage polarization in BPH-1 cells. AR knockdown partially abolished the beneficial effects of Apo in prostate cells, indicating AR-dependent effects of Apo.

CONCLUSION

In contrast with existing BPH therapies, Apo may provide a new application for prostatic disease treatment, especially for BPH, by targeting the AR/TGF-β/NOX4 signaling pathway.

Increased Risk of Benign Prostate Hyperplasia (BPH) in Patients with Gout: A Longitudinal Follow-Up Study Using a National Health Screening Cohort

A previous study reported a high risk of benign prostatic hyperplasia (BPH) in patients with gout. This study intended to evaluate the risk of BPH in gout patients. A total of 514,866 Korean National Health Insurance Service-Health Screening Cohorts were retrieved from 2002 to 2019. Among these individuals, 14,961 gout patients and 58,764 control participants were matched based on demographic factors. The incidence of BPH during the follow-up periods was collected for both the gout and control groups. The risk of BPH was analyzed using stratified Cox proportional hazard models, and hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. Secondary analyses were conducted based on demographic factors and comorbidities. The incidence of BPH was 23.40% in gout patients and 20.70% in control participants. In the adjusted model, the HR of BPH was 1.13-fold higher in gout patients than in the control group (95% CI = 1.09-1.18). Compared with the ≥60-year-old group, the <60-year-old group demonstrated a higher HR for BPH in gout patients (1.19 [1.13-1.24] vs. 1.07 [1.01-1.13]). The risk of BPH in gout patients was consistent according to various comorbidities. Patients with gout demonstrated a greater risk of BPH than participants without gout. The young adult population had a higher risk of BPH related to gout.

Association of serum uric acid levels with benign prostatic hyperplasia in US men: results from NHANES 2005-2008

BACKGROUND

The relationship between uric acid (UA) and benign prostatic hyperplasia (BPH) is controversial and has rarely been studied in American populations.

METHODS

Data from two cycles of the National Health and Nutrition Examination Surveys, comprising data from 2005 to 2008, were used. The majority of BPH were identified by self-report. We investigated the relationship between UA and BPH using univariate and multivariate logistic regression analyses.

RESULTS

2,845 participants were enrolled in the study, including 531 participants with BPH and 2,314 controls. After fully adjusting for all confounders, the risk of developing BPH was reduced by 18% for every 100 μmol/L increase in UA (OR = 0.82, 95% CI: 0.69-0.97, p = 0.023). Participants in the highest quartile of UA were found to have a reduced likelihood of developing BPH (ORQ4vs1 = 0.61, 95% CI: 0.41-0.91) in comparison to those in the lowest quartile of UA. Subgroup analyses found that among those younger than 60 years, non-Hispanic whites, former smokers, heavy drinkers, those without diabetes, or those with hypertension, high UA remained negatively associated with BPH.

CONCLUSIONS

The above results suggest that UA may be a potential protective factor for BPH, but the mechanism needs to be further explored.

Association between serum uric acid and prostate cancer mortality in androgen deprivation therapy: A population-based cohort study

OBJECTIVE

This population-based study examined the association between baseline uric acid (UA) and prostate cancer (PCa)-related mortality amongst PCa patients receiving androgen deprivation therapy (ADT).

METHODS

Adults with PCa who received ADT in Hong Kong between December 1999 and March 2021 were identified. Patients with missing baseline UA were excluded. Patients were followed up until September 2021. The outcome was PCa-related mortality.

RESULTS

Altogether, 4126 patients (median follow-up 3.1[interquartile range 1.4-6.0] years) were included. A J-shaped association was observed between baseline UA level and PCa-related mortality risk, with a direct association in those with mean(0.401 mmol/L) or above-mean baseline UA levels (hazard ratio (HR) per standard deviation-increase 1.35 [95% confidence interval 1.21,1.51], p < 0.001), and an inverse association in those with below-mean baseline UA levels (HR 0.78[0.67,0.92], p = 0.003). The former remained significant on competing risk regression, but not the latter.

CONCLUSIONS

A J-shaped relationship between baseline UA level and PCa-related mortality risk was identified. This study was mainly limited by potential unmeasured and residual confounders. Further validation studies are warranted.

Investigating the Anti-inflammatory Effect of Allopurinol on the Prevention of Prostate Cancer

Introduction Gout is a form of arthritis that arises from the accumulation of uric acid in the bloodstream. Allopurinol, a medication that reduces uric acid levels, has also been shown to have anti-inflammatory effects. Research in this area seems to have mixed results. Furthermore, limited research has examined the relationship between gout treated with Allopurinol and its possible protective factors against prostate cancer. The purpose of this study was to examine the relationship between Allopurinol use and prostate cancer, controlling for demographic and metabolic factors. Methods Information was collected from the National Health and Nutrition Examination Survey (NHANES) dataset of the Centers for Disease Control and Prevention (CDC). Logistic regression analysis was employed to establish the correlation between the usage of Allopurinol and the occurrence of prostate cancer while considering variables such as weight, hypertension, hyperlipidemia, race, educational level, and marital status. The research received approval from the review board of the Physician's Journal of Medicine. Results We found no significant association between Allopurinol use and prostate cancer, controlling for covariates. Age was found to have a positive association with prostate cancer. Marriage was found to have a negative association with prostate cancer. Conclusion The results of this study did not find a significant association between Allopurinol use and the risk of prostate cancer. However, this study adds to the limited body of research examining the relationship between gout, Allopurinol, and prostate cancer and suggests that further research is needed in this area. Overall, while Allopurinol has been shown to have anti-inflammatory effects and is used to treat gout, its use does not appear to have a significant impact on the risk of developing prostate cancer.

Activin B and Activin C Have Opposing Effects on Prostate Cancer Progression and Cell Growth

Current prognostic and diagnostic tests for prostate cancer are not able to accurately distinguish between aggressive and latent cancer. Members of the transforming growth factor-β (TGFB) family are known to be important in regulating prostate cell growth and some have been shown to be dysregulated in prostate cancer. Therefore, the aims of this study were to examine expression of TGFB family members in primary prostate tumour tissue and the phenotypic effect of activins on prostate cell growth. Tissue cores of prostate adenocarcinoma and normal prostate were immuno-stained and protein expression was compared between samples with different Gleason grades. The effect of exogenous treatment with, or overexpression of, activins on prostate cell line growth and migration was examined. Activin B expression was increased in cores containing higher Gleason patterns and overexpression of activin B inhibited growth of PNT1A cells but increased growth and migration of the metastatic PC3 cells compared to empty vector controls. In contrast, activin C expression decreased in higher Gleason grades and overexpression increased growth of PNT1A cells and decreased growth of PC3 cells. In conclusion, increased activin B and decreased activin C expression is associated with increasing prostate tumor grade and therefore have potential as prognostic markers of aggressive prostate cancer.

Alpha-mangostin counteracts hyperuricemia and renal dysfunction by inhibiting URAT1 renal transporter in insulin resistance rat model

Background

Alpha-mangostin (AM) has been shown to have hypoglycemic activity. This study aimed to analyze the effects of AM at a dose of 100 mg/kg and 200 mg/kg to alleviate hyperuricemia and renal dysfunction on high-fat/high-glucose diet and low dose streptozotocin (HF/HG/STZ) injection-induced IR rat model. IR was induced in male Wistar rats by giving a HF/HG diet for 11 weeks and single injection of STZ (35 mg/kg, i.p.), then divided randomly into IR rats, IR rats treated with AM 100 and 200 mg/kgBW given by gavage for 8 weeks. At the end of the 11th week, all rats were killed, and the kidneys were taken to be analyzed for urate transporters 1 (URAT1) and glucose transporters 9 (GLUT9). We also assessed serum uric acid, proteinuria, BUN, creatinine clearance, HOMA-IR, and fasting blood glucose (FBG).

Results

We have found the significant increase in HOMA-IR and FBG levels of the IR rats, in comparison with its control groups, which were decreased significantly after AM administration at both doses. URAT1 and GLUT9 mRNA and protein expressions in kidney in the IR + AM at both doses groups also decreased compared those in the IR without treatment group, though the decrease in GLUT9 did not appear to be statistically significant. Consequently, hyperuricemia and renal dysfunction were attenuated by AM treatment at both doses.

Conclusion

After considering all findings, AM might be a potential candidate to ameliorate IR-induced hyperuricemia and renal dysfunction at least in part by modulating the renal URAT1.

Higher Levels of Serum Uric Acid Have a Significant Association with Lower Incidence of Lower Urinary Tract Symptoms in Healthy Korean Men

Gout has been correlated with the risk of incident benign prostatic hyperplasia. In line with increasing prevalence of hyperuricemia, the aim of this study was to investigate the relationship between serum uric acid (SUA) level and the incidence of lower urinary tract symptoms (LUTS) among clinically healthy middle-aged men. We performed a cohort study in 101,091 Korean men without LUTS at baseline who completed health checkups between 2011 and 2016. LUTS were evaluated using the International Prostate Symptom Score, where a score ≥ 8 was defined as significant LUTS. Men were divided into six groups according to their SUA levels in mg/dL (<5.5, 5.5−6.4, 6.5−7.4, 7.5−8.4, 8.5−9.4, and ≥9.5). Throughout the follow-up—encompassing a total of 358,982.6 person years—13,424 people had significant LUTS (37.3 per 1000 person years for incidence rate). The multivariable models demonstrated that the highest level of SUA (≥9.5 mg/dL) was related to the lowest risk of significant LUTS compared with the reference category (<5.5 mg/dL) (0.77 (95% CI 0.59−0.99) for adjusted HR). In this large cohort composed of middle-aged men, higher SUA levels were related to a reduced risk of LUTS. This result suggests another potential role of SUA in restraining LUTS. Additional studies are needed to explain the underlying biological mechanisms of this phenomenological relationship.

Is there relationship between serum uric acid levels and lower urinary tract symptoms, prostate volume, and PSA in men without cancer? A prospective population-based study

There are conflicting results about uric acid (UA) effect on the prostate. We investigated the relationship between UA and PSA, free PSA, prostate volume and international prostate symptoms score (IPSS) in benign prostate hyperplasia (BPH). This study was conducted in BPH men without cancer who were referred for annual health workup (N = 910) from 2017 to 2020. The mean ages were 67.28 ± 9.2 years. UA was positively related to IPSS and PSA (r = 0.210, p = .023 and r = 0.156, p = .041 respectively) and also negatively related to free/total PSA ratio (r = -0.332, p = .01) but not related to prostate volume (r = 0.036, p = .696). After adjustment for age, BMI and prostate volume, there were significant relationships between hyperuricaemia and PSA, free/total PSA ratio, and IPSS (95% CI: 0.254-1.645, OR = 0.647, p = .039; 95% CI: 0.076-0.899, OR = 0.270, p = .033 and 95% CI: 1.011-3.386, OR = 1.851, p = .038 respectively). These results should be considered during the general assessment of the patients with BPH. The findings raise the possible hypothesis of relationship between serum UA with IPSS and PSA which should be investigated by future studies.

The modulatory effects of cinnamaldehyde on uric acid level and IL-6/JAK1/STAT3 signaling as a promising therapeutic strategy against benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a widespread disorder in elderly men. Cinnamaldehyde, which is a major constituent in the essential oil of cinnamon, has been previously reported to reduce xanthine oxidase activity, in addition to its anti-inflammatory, anti-oxidant, and anti-proliferative activities. Our study was designed to investigate the potential modulatory effects of cinnamaldehyde on testosterone model of BPH in rats through reduction of uric acid level, and suppression of IL-6/JAK1/STAT3 signaling pathway. Cinnamaldehyde (40 and 75 mg/kg) was orally administered to male Wistar rats for 3 weeks, and concurrently with testosterone (3 mg/kg, s.c.) from the second week. Cinnamaldehyde ameliorated the elevation in prostatic weight and index compared to rats treated with testosterone only, that was also confirmed by alleviation of histopathological changes in prostate architecture. The protective mechanisms of cinnamaldehyde were elucidated through inhibition of xanthine oxidase activity and reduced uric acid level. That was accompanied by reduction of the pro-inflammatory cytokines; interleukin-6 (IL-6), IL-1β, tumor necrosis factor-alpha (TNF-α), and the nuclear translocation of the transcription factor NF-κB p65, that could be attributed also to the enhanced anti-oxidant defense by cinnamaldehyde. The protein expression of JAK1, which is IL-6 receptor linked protein, was reduced with subsequently reduced activation of STAT3 protein. That eventually suppressed the formation of the proliferation protein cyclin D1, while elevated Bax/Bcl2 ratio. It can be concluded that reducing uric acid level through xanthine oxidase inhibition and suppression of the inflammatory signaling cascade; IL-6/JAK1/STAT3; by cinnamaldehyde could be a novel and promising therapeutic approach against BPH.

Vibrational spectroscopy of liquid biopsies for prostate cancer diagnosis

Background:

Screening for prostate cancer with prostate specific antigen and digital rectal examination allows early diagnosis of prostate malignancy but has been associated with poor sensitivity and specificity. There is also a considerable risk of over-diagnosis and over-treatment, which highlights the need for better tools for diagnosis of prostate cancer. This study investigates the potential of high throughput Raman and Fourier Transform Infrared (FTIR) spectroscopy of liquid biopsies for rapid and accurate diagnosis of prostate cancer.

Methods:

Blood samples (plasma and lymphocytes) were obtained from healthy control subjects and prostate cancer patients. FTIR and Raman spectra were recorded from plasma samples, while Raman spectra were recorded from the lymphocytes. The acquired spectral data was analysed with various multivariate statistical methods, principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and classical least squares (CLS) fitting analysis.

Results:

Discrimination was observed between the infrared and Raman spectra of plasma and lymphocytes from healthy donors and prostate cancer patients using PCA. In addition, plasma and lymphocytes displayed differentiating signatures in patients exhibiting different Gleason scores. A PLS-DA model was able to discriminate these groups with sensitivity and specificity rates ranging from 90% to 99%. CLS fitting analysis identified key analytes that are involved in the development and progression of prostate cancer.

Conclusions:

This technology may have potential as an alternative first stage diagnostic triage for prostate cancer. This technology can be easily adaptable to many other bodily fluids and could be useful for translation of liquid biopsy-based diagnostics into the clinic.

Phosphoribosyl pyrophosphate synthetases 2 knockdown inhibits prostate cancer progression by suppressing cell cycle and inducing cell apoptosis

Phosphoribosyl pyrophosphate synthetases 2 (PRPS2) protein function as nucleotide synthesis enzyme that plays vital roles in cancer biology. However, the expression profile and function of PRPS2 in prostate cancer (PCa) remain to be identified. Here we investigated the expression of PRPS2 protein in human PCa and paired normal tissues by immunohistochemistry, meanwhile the regulatory effects on cell proliferation, apoptosis and growth of xenograft tumors in nude mice were evaluated in PCa cells with PRPS2 depletion. Moreover, the signaling pathways were also explored by western blot analysis and quantitative polymerase chain reaction assays. We found that PRPS2 was dramatically upregulated in prostate adenocarcinoma tissues in comparison with normal tissues, and that increased PRPS2 was linked intimately to advanced clinical stage and pT status. Functional experiments showed that knockdown of PRPS2 significantly suppressed cell growth both in vitro and in vivo. In addition, depletion of PRPS2 induced G₁ phase cell cycle arrest and elevated cell apoptosis. Silencing of PRPS2 resulted in the decreased expression of Bcl‑2 and cyclinD1 and increased levels of Bax, cleavage of caspases‑3, caspases‑9 and PARP. Furthermore, we also detected PRPS2 expression was significantly induced after DHT treatment, which implied the important role of PRPS2 in oncogenesis of PCa. Taken together, our findings elucidated that PRPS2 may be a potential novel candidate for PCa therapy.

Hyperuricaemic UrahPlt2/Plt2 mice show altered T cell proliferation and defective tumor immunity after local immunotherapy with Poly I:C

Hyperuricaemia is associated with various metabolic dysfunctions including obesity, type 2 diabetes mellitus, hypertension and in general metabolic syndrome, which are all associated with increased risk of cancer. However, the direct association between elevated uricemia and cancer mortality still remains unclear. In this study, we used a mouse model of hyperuricemia, the Urah^plt2/plt2 (PLT2) mouse, to investigate the effect of high uric acid levels on anti-tumor immune responses and tumor growth. In normo-uricaemic C57BL/6 mice injected with B16 melanomas, immunotherapy by treatment with Poly I:C at the tumor site delayed tumor growth compared to PBS treatment. In contrast, Poly I:C-treated hyper-uricaemic PLT2 mice were unable to delay tumor growth. Conventional and monocyte-derived dendritic cells in the tumor-draining lymph nodes (dLN) of C57BL/6 and PLT2 mice were similarly increased after Poly I:C immunotherapy, and expressed high levels of CD40 and CD86. CD8⁺ T cells in the tumor-dLN and tumor of both WT and PLT2 mice were also increased after Poly I:C immunotherapy, and were able to secrete increased IFNγ upon in vitro restimulation. Surprisingly, tumor-specific CD8⁺ T cells in dLN were less abundant in PLT2 mice compared to C57BL/6, but showed a greater ability to proliferate even in the absence of cognate antigen. These data suggest that hyperuricaemia may affect the functionality of CD8⁺ T cells in vivo, leading to dysregulated T cell proliferation and impaired anti-tumor activity.

Comparison of serum uric acid levels between prostate cancer patients and a control group

Introduction

The aim of this study is to investigate whether the uric acid levels, measured in the serum of patients with a new prostate cancer diagnosis, differ from those in the healthy subjects.

Material and methods

The study included 117 patients who applied to our clinic due to a high prostate specific antigen (PSA) with prostate cancer diagnosis from 2013–2016 and 114 patients applying in the same period for other reasons. The serum uric acid levels and inflammatory markers like c-reactive protein (CRP) and neutrophil count were compared between the groups.

Results

The age distribution of the patients in the prostate cancer and control group was 67.6 ±9.4 and 62 ±8.5 years, respectively. The uric acid levels were identified as 5.05 ±1.14 and 6.04 ±1.12 in the prostate cancer and control group, respectively. Additionally, inflammatory markers like CRP and neutrophil count were identified to be high in the prostate cancer group (p <0.05).

Conclusions

The uric acid levels measured in serum of patients with a prostate cancer diagnosis were reduced compared to the control group and inflammatory markers were found to be increased. Low serum uric acid levels and increased inflammatory markers were determined as risk factors for prostate cancer.

Risk of incident benign prostatic hyperplasia in patients with gout: a retrospective cohort study

BACKGROUND

This retrospective cohort study evaluated the association between gout and the risk of benign prostatic hyperplasia among men by using data from Taiwan's National Health Insurance Research Database.

METHODS

Population-based representative insurance (outpatient and inpatient) claims data of 29,269 patients with gout and 29,269 matched patients without gout (1:1 ratio) for the period of 1997-2010 in Taiwan were identified. The association between gout and benign prostatic hyperplasia was evaluated using the Cox proportional hazards model. The associations of age by gout and gout phenotypes with benign prostatic hyperplasia risk were estimated.

RESULTS

Patients with gout had a higher incidence rate of benign prostatic hyperplasia than those in the matched gout-free group (19.62 vs. 10.11 events per 1000 person-years). Compared with the gout-free group, the adjusted hazard ratios (HRs) (95% confidence intervals (CIs)) for benign prostatic hyperplasia were 1.30 (1.24-1.36). The gout-to-benign prostatic hyperplasia association was modified by age (P_interaction < 0.0001) in gout patients the age groups of 20-40 years (adjusted HR 2.74, P < 0.0001) and 41-60 years (adjusted HR 1.39, P < 0.0001) but not in the age group of >60 years (adjusted HR 1.07, P = 0.063). Compared with gouty tophi, a higher risk of benign prostatic hyperplasia was noted in gouty nephropathy (adjusted HR 1.30, 95% CI 1.12-1.50).

CONCLUSIONS

Our results suggest that male gout is positively related to benign prostatic hyperplasia, particularly in young gout patients and those with gouty nephropathy.

Allopurinol and risk of benign prostatic hyperplasia in a Finnish population-based cohort

BACKGROUND

Metabolic syndrome and obesity are linked with hyperuricemia, and it has also been proposed that oxidative stress associated with hyperuricemia may promote benign prostatic hyperplasia (BPH). However, it is currently unknown whether use of antihyperuricemic medication is associated with risk of developing BPH. We studied the association between BPH and use of antihyperuricemic allopurinol in a Finnish population-based cohort.

METHODS

The study cohort consisted of 74,754 men originally identified for the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC). Information on gout and BPH medication usage (5α-reductase inhibitors, 5ARIs) during 1996-2014 was obtained from the National medication reimbursement database. Information on BPH diagnoses from in- and outpatient hospital visits and BPH-related surgery was obtained from the National Health Care Registry. Men with a record of BPH at baseline was excluded. We used Cox regression to analyze risk of starting BPH medication, having a recorded diagnosis or undergoing BPH surgery by allopurinol use with adjustment for age and simultaneous use of statins, antidiabetic or antihypertensive drugs and aspirin or other NSAIDs. Medication use was analyzed as a time-dependent variable to minimize immortal time bias.

RESULTS

Men using allopurinol had a decreased risk for all three BPH endpoints: BPH medication (HR 0.81; 95% CI 0.75-0.88), BPH diagnosis (HR 0.78; 95% CI 0.71-0.86) and BPH-related surgery (HR 0.67; 95% CI 0.58-0.76) after multivariable adjustment. The risk association did not change by cumulative use. The risk decrease disappeared after 1-2 years lag time. Only BMI modified the risk association; the risk decrease was observed only among men with BMI above the median (27.3 kg/m²); p for interaction <0.05 for each endpoint.

CONCLUSIONS

We found that allopurinol use is associated with lowered risk of BPH medication, diagnosis and surgery. A possible explanation could be antioxidative effects of urate-lowering allopurinol.

Recent advances on uric acid transporters

Uric acid is the product of purine metabolism and its increased levels result in hyperuricemia. A number of epidemiological reports link hyperuricemia with multiple disorders, such as kidney diseases, cardiovascular diseases and diabetes. Recent studies also showed that expression and functional changes of urate transporters are associated with hyperuricemia. Uric acid transporters are divided into two categories: urate reabsorption transporters, including urate anion transporter 1 (URAT1), organic anion transporter 4 (OAT4) and glucose transporter 9 (GLUT9), and urate excretion transporetrs, including OAT1, OAT3, urate transporter (UAT), multidrug resistance protein 4 (MRP4/ABCC4), ABCG-2 and sodium-dependent phosphate transport protein. In the kidney, uric acid transporters decrease the reabsorption of urate and increase its secretion. These transporters’ dysfunction would lead to hyperuricemia. As the function of urate transporters is important to control the level of serum uric acid, studies on the functional role of uric acid transporter may provide a new strategy to treat hyperuricemia associated diseases, such as gout, chronic kidney disease, hyperlipidemia, hypertension, coronary heart disease, diabetes and other disorders. This review article summarizes the physiology of urate reabsorption and excretion transporters and highlights the recent advances on their roles in hyperuricemia and various diseases.

Long-term allopurinol use decreases the risk of prostate cancer in patients with gout: a population-based study

BACKGROUND

Clinical observations indicated an increased risk of developing prostate cancer in gout patients. Chronic inflammation is postulated to be one crucial mechanism for prostate carcinogenesis. Allopurinol, a widely used antigout agent, possesses potent anti-inflammation capacity. We elucidated whether allopurinol decreases the risk of prostate cancer in gout patients.

METHODS

We analyzed data retrieved from Taiwan National Health Insurance Database between January 2000 and December 2012. Patients diagnosed with gout during the study period with no history of prostate cancer and who had never used allopurinol were selected. Four allopurinol use cohorts (that is, allopurinol use (>365 days), allopurinol use (181-365 days), allopurinol use (91-180 days) and allopurinol use (31-90 days)) and one cohort without using allopurinol (that is, allopurinol use (No)) were included. The study end point was the diagnosis of new-onset prostate cancer. Multivariable Cox proportional hazards regression and propensity score-adjusted Cox regression models were used to estimate the association between the risk of prostate cancer and allopurinol treatment in gout patients after adjusting for potential confounders.

RESULTS

A total of 25 770 gout patients (aged between 40 and 100 years) were included. Multivariable Cox regression analyses revealed that the risk of developing prostate cancer in the allopurinol use (>365 days) cohort was significantly lower than the allopurinol use (No) cohort (adjusted hazard ratio (HR)=0.64, 95% confidence interval (CI)=0.45-0.9, P=0.011). After propensity score adjustment, the trend remained the same (adjusted HR=0.66, 95% CI=0.46-0.93, P=0.019).

CONCLUSIONS

Long-term (more than 1 year) allopurinol use may associate with a decreased risk of prostate cancer in gout patients.