Growth factor, cytokine, and vitamin D receptor polymorphisms and risk of benign prostatic hyperplasia in a community-based cohort of men

Effects of poloxamer-based thermo-sensitive sol-gel agent on urethral stricture after transurethral resection of the prostate for benign prostatic hyperplasia: a multicentre, single-blinded, randomised controlled trial

OBJECTIVE

To evaluate the effectiveness of poloxamer-based thermo-sensitive sol-gel instillation, after transurethral resection of the prostate (TURP), for preventing urethral stricture.

PATIENTS AND METHODS

In all, 198 patients underwent TURP for benign prostatic hyperplasia. Recruited patients were randomly divided into two groups: groups A and B. Patients in Group A (100 patients, experimental group) received poloxamer-based thermo-sensitive sol-gel instillation and patients in the Group B (98 patients, control group) received lubricant instillation after TURP. Each patient was evaluated at 4 (V1), 12 (V2), and 24 weeks (V3) after TURP. The effectiveness of poloxamer-based thermo-sensitive sol-gel instillation was evaluated based on the International Prostate Symptom Score (IPSS), IPSS-Quality of Life (QoL), Overactive bladder questionnaire (OAB-q), maximum urinary flow rate (Q_max ), post-void residual urine volume (PVR), and cystoscopy.

RESULTS

Amongst the initial 198 participants, 80 patients in Group A and 83 in Group B completed the study. There were no significant differences in IPSS-QoL and OAB-q between the groups. However, Q_max was significantly different between groups A and B, at a mean (SD) of 18.92 (9.98) vs 15.58 (9.24) mL/s (P = 0.028) at 24 weeks after TURP. On cystoscopic examination, urethral stricture after TURP was found in two of the 80 patients in Group A and 10 of 83 in Group B (P = 0.023).

CONCLUSIONS

Poloxamer-based thermo-sensitive sol-gel instillation after TURP lowered the incidence of urethral stricture.

Association of Circulating 25(OH)D and Lower Urinary Tract Symptoms: A Four-Year Prospective Study among Elderly Chinese Men

The role of vitamin D in relation to lower urinary tract symptoms (LUTS) remains inconclusive. This four-year longitudinal study aims to explore the association of circulating 25(OH)D and LUTS in elderly Chinese men. Two thousand Chinese men aged 65 and older were recruited from a local community, of which 1998 (99.9%) at baseline and 1564 (78.2%) at four-year follow-up reported data on LUTS, and 988 of the randomly chosen subpopulation were assayed for serum 25(OH)D by radioimmunoassay at baseline. LUTS were evaluated by a validated International Prostate Symptoms Scale (IPSS). Data on demographic characteristics, lifestyle factors, health, and medications were collected. Serum parathyroid and sex steroid hormones and genotypes of vitamin D receptors were assayed. The association of serum 25(OH)D and LUTS was examined by using multivariable regression models. Serum 25(OH)D was not significantly associated with the changes of IPSS or the risk of LUTS in overall participants. However, among men with 25(OH)D ≤ 60 nmol/L, each 10 nmol/L increase of 25(OH)D over 0 nmol/L was significantly associated with 1.3 lower points of IPSS or a 51.6% decreased risk for moderate/severe LUTS four years later. Adjustment for serum androstenedione (p = 0.019) and dehydropiandrosterone (p = 0.037) attenuated the associations. Our study suggested that among individuals with low vitamin D status, the increase of the 25(OH)D level may be associated with a lowered risk of LUTS.

Association of variants in genes related to the immune response and obesity with BPH in CLUE II

BACKGROUND

Chronic inflammation and obesity may contribute to the genesis or progression of BPH and BPH-associated lower urinary tract symptoms (LUTS). The influence of variants in genes related to these states on BPH has not been studied extensively. Thus, we evaluated the association of 17 single-nucleotide polymorphisms (SNPs) in immune response genes (IL1B, IL6, IL8, IL10, TNF, CRP, TLR4 and RNASEL) and genes involved in obesity, including insulin regulation (LEP, ADIPOQ, PPARG and TCF7L2), with BPH.

METHODS

BPH cases (N = 568) and age-frequency matched controls (N=568) were selected from among adult male CLUE II cohort participants who responded in 2000 to a mailed questionnaire. BPH was defined as BPH surgery, use of BPH medications or symptomatic BPH (American Urological Association Symptom Index Score ⩾ 15). Controls were men who had not had BPH surgery, did not use BPH medications and whose symptom score was ⩽ 7. Age-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression.

RESULTS

None of the candidate SNPs was statistically significantly associated with BPH. However, we could not rule out possible weak associations for CRP rs1205 (1082C>T), ADIPOQ rs1501299 (276C>A), PPARG rs1801282 (-49C>G) and TCF7L2 rs7903146 (47833T>C). After summing risk alleles, men with ⩾ 4 had an increased BPH risk compared with those with ⩽ 1 (OR, 1.78; 95% CI, 1.10-2.89; P(trend) = 0.006).

CONCLUSIONS

SNPs in genes related to immune response and obesity, especially in combination, may be associated with BPH.

Meta-analysis of vitamin D receptor gene polymorphisms and benign prostatic hyperplasia risk

The association between vitamin D receptor (VDR) gene polymorphisms and risk of benign prostatic hyperplasia (BPH) has been investigated in numerous publications, but published results remain inconclusive. Hence, we conducted this meta-analysis to derive a more precise conclusion. Four polymorphisms (Taq-I, Bsm-I, Apa-I, and Fok-I) of the VDR gene with risk of BPH from six case-control studies and one cohort study involving 2,248 individuals were identified from PubMed and China National Knowledge Internet databases up to November 20, 2013 (updated on March 5, 2014). After data extraction, the meta-analysis was performed using Comprehensive Meta-Analysis software. All four VDR polymorphisms were not associated with the risk of BPH [Taq-I: OR 0.61, 95 % CI (0.38-1.24) for tt vs. TT; Bsm-I: OR 1.27, 95 % CI (0.96-1.69) for bb vs. BB; Apa-I: OR 1.26, 95 % CI (0.64-2.46) for aa vs. AA; Fok-I: OR 0.95, 95 % CI (0.60-1.50) for ff vs. FF]. Subgroup analysis according to ethnicity for Taq-I polymorphism also showed that the polymorphism was not associated with risk of BPH for either Caucasians [OR 0.74, 95 % CI (0.31-1.78) for tt vs. TT] or Asians [OR 0.35, 95 % CI (0.11-1.11) for tt vs. TT]. However, results of this meta-analysis should be treated with caution because this meta-analysis has several limitations. We propose to conduct a high-quality study with large sample size to further identify the association between VDR gene polymorphisms and BPH susceptibility.

Involvement of fibroblast growth factor receptor genes in benign prostate hyperplasia in a Korean population

Fibroblast growth factors (FGFs) and their receptors (FGFRs) have been implicated in prostate growth and are overexpressed in benign prostatic hyperplasia (BPH). In this study, we investigated whether single nucleotide polymorphisms (SNPs) of the FGFR genes (FGFR1 and FGFR2) were associated with BPH and its clinical phenotypes in a population of Korean men. We genotyped four SNPs in the exons of FGFR1 and FGFR2 (rs13317 in FGFR1; rs755793, rs1047100, and rs3135831 in FGFR2) using direct sequencing in 218 BPH patients and 213 control subjects. No SNPs of FGFR1 or FGFR2 genes were associated with BPH. However, analysis according to clinical phenotypes showed that rs1047100 of FGFR2 was associated with prostate volume in BPH in the dominant model (GA/AA versus GG, P = 0.010). In addition, a significant association was observed between rs13317 of FGFR1 and international prostate symptom score (IPSS) in the additive (TC versus CC versus TT, P = 0.0022) and dominant models (TC/CC versus TT, P = 0.005). Allele frequency analysis also showed significant association between rs13317 and IPSS (P = 0.005). These results suggested that FGFR genes could be related to progression of BPH.

Vitamin D receptor as a therapeutic target for benign prostatic hyperplasia

The bioactive form of vitamin D, 1α, 25-dihydroxyvitamin D3 (1α, 25(OH)2D3), is a secosteroid hormone that binds to the vitamin D receptor (VDR), a member of the nuclear receptor super-family expressed in many cell types, and modulates a variety of biological functions. 1α, 25(OH)2D3 is essential for bone and mineral homeostasis, but also regulates growth and differentiation of multiple cell types, and displays immunoregulatory and anti-inflammatory activities. The antiproliferative, prodifferentiative, antibacterial, immunomodulatory and anti-inflammatory properties of synthetic VDR agonists could be exploited to treat a variety of chronic inflammatory and autoimmune diseases, including benign prostatic hyperplasia (BPH). It has been hypothesized that VDR may influence both the risk of a variety of diseases and their occurrence and prognosis. However, earlier studies investigating the associations between specific VDR polymorphisms and various diseases often show controversial results. We performed a systematic review of the current literature on vitamin D and BPH using the PubMed and Web of Knowledge databases. The aim of this review is to summarize the current knowledge on the utility of the VDR gene regarding prostate growth as well as the pathogenesis and treatment of BPH, a complex syndrome characterized by a static component related to prostate overgrowth, a dynamic component responsible for urinary storage symptoms, and an inflammatory component. Despite the massive advances in recent decades, further research is needed to fully characterize the exact underlying mechanisms of VDR action on BPH and to comprehend how these cellular changes translate into clinical development in physical concert.

Outcomes and quality of life issues in the pharmacological management of benign prostatic hyperplasia (BPH)

BACKGROUND

Benign prostatic hyperplasia (BPH) is a common disease of the aging male population. BPH treatment includes a variety of pharmacological and surgical interventions. The goal of this paper is to review the natural history of BPH, outcomes of pharmacological management, effects on quality of life (QoL), future pharmacotherapies, and associated patient-focused perspectives.

MATERIALS AND METHODS

Medline searches for the keywords benign prostatic hyperplasia, BPH, alpha blockers, 5 alpha-reductase, and quality of life were performed. Relevant literature was reviewed and analyzed.

RESULTS

Alpha blockers, 5 alpha-reductase inhibitors, and phytotherapy are the three categories of pharmaceutical interventions currently available for BPH. Various clinical trials have shown that alpha blockers and 5 alpha-reductase inhibitors are safe, efficacious, and improve QoL in patients with BPH. The evidence for phytotherapeutics is not as convincing. The current armamentarium of pharmaceutical interventions are encompassed in these three classes of medications. New pharmacotherapies based on novel mechanisms are on the horizon.

CONCLUSION

There are a variety of safe and efficacious medical therapies available for the management of BPH and it is important for the practicing physician to have an understanding of these pharmacotherapies and their potential impact on the patient. There is not enough evidence to make a recommendation regarding phytotherapy use. New classes of drugs for BPH will likely find their way into routine use.

Association of IL10, IL10RA, and IL10RB polymorphisms with benign prostate hyperplasia in Korean population

Cytokines such as interleukin 10 (IL10) may play an important role in the process of inflammation. The aim of this study was to analyze the association between IL10, IL10RA and IL10RB single nucleotide polymorphisms (SNPs), and benign prostate hyperplasia (BPH) in Korean population. All patients with BPH were divided into two groups according to international prostate symptom score (IPSS), prostate specific antigen (PSA) level, Q(max), and prostate volume. We selected two IL10 SNPs (rs1518111 and rs1554286), three IL10RA SNPs (rs2256111, rs4252243, and rs2228054), and two IL10RB SNPs (rs999788 and rs2834167). Genotypes of seven SNPs were determined through direct sequencing. The G/G genotype of IL10RB polymorphism (rs2834167) was associated with a high PSA level compared with the A/G + A/A genotypes (P = 0.009). Of IL10 SNP, the A/A genotype of rs1518111 and T/T genotype of rs1554286 were associated with small prostate volume, respectively (P = 0.011, P = 0.014). Moreover, the T/T genotype of IL10RB polymorphism (rs999788) was associated with high prostatic volume compared with the T/C + C/C genotypes (P = 0.033). The linkage disequilibrium (LD) blocks were formed in IL10 and IL10RA. However, haplotypes in the LD block were not associated with BPH. It is concluded that there is a strong association between the IL10 and IL10RB SNPs, and BPH in Korean population.

Association of Pro/Anti-inflammatory Cytokine Gene Polymorphisms with Benign Prostate Hyperplasia Risk

Benign prostate hyperplasia (BPH) is a common condition in aged men and result from prolong chronic inflammation in prostate gland. Cytokines are important molecules responsible for inflammation. Single nucleotide polymorphisms (SNPs) in promoter region of cytokine genes have been shown to alter the level of cytokines. Hence we evaluated the association of pro-inflammatory and anti-inflammatory cytokine SNPs in a North Indian cohort of BPH patients. We observed that IL-1B -511 CT + TT genotypes conferred protective effect for susceptibility to BPH (OR 0.39, P 0.001). Our results also demonstrated that TNF-A -1031 C allele to be associated with risk for BPH (OR 1.89, P < 0.0001). Moreover, we also observed twofold risk for IL-10 -1082 cytokine gene polymorphism (OR 1.96, P 0.048). No association was observed with risk of BPH for IFN-G +874, IL-1 RN VNTR, IL-6 -174, IL-10 -819 and TGF-B +28. Our findings of IL-1B -511, TNF-A -1031 and IL-10 -1082 suggested that these variants play important role in susceptibility to BPH. Future studies in large cohort of different ethnicity BPH groups are warranted to establish definite associations with other cytokine gene polymorphisms as well.

Attenuated proliferation and trans-differentiation of prostatic stromal cells indicate suitability of phosphodiesterase type 5 inhibitors for prevention and treatment of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is characterized by tissue overgrowth and stromal reorganization primarily due to cellular proliferation and fibroblast-to-myofibroblast trans-differentiation. To evaluate the potential of phosphodiesterase type 5 (PDE5) inhibitors like tadalafil for prevention and treatment of BPH, we analyzed the role of the nitric oxide/cyclic GMP (cGMP)/PDE5 pathway for cellular proliferation and TGFbeta1-induced fibroblast-to-myofibroblast trans-differentiation in primary prostate stromal cells. Inhibition by tadalafil of PDE5, which is mainly expressed in the stromal compartment of the prostate, reduced proliferation of primary prostate stromal cells and to a lesser extent of primary prostate basal epithelial cells. Attenuated proliferation due to elevated intracellular cGMP levels was confirmed by inhibition of the cGMP-dependent protein kinase G by its inhibitor KT2358. Moreover, tadalafil strongly attenuated TGFbeta1-induced fibroblast-to-myofibroblast trans-differentiation. The inhibitory effect on trans-differentiation was also observed after small interfering RNA-mediated PDE5 knockdown. As confirmed by the MAPK kinase 1 inhibitor PD98059, this effect was mediated via MAPK kinase 1 signaling. We conclude that BPH patients might benefit from adjuvant therapies with PDE5 inhibitors that inhibit stromal enlargement due to cell proliferation, as well as TGFbeta1-induced trans-differentiation processes.

Increased expression of NKX3.1 in benign prostatic hyperplasia

OBJECTIVES

To establish the role of the NKX3.1 gene in the development of benign prostatic hyperplasia by comparing the expression of NKX3.1 in messenger ribonucleic acid (mRNA) and protein levels in young adult prostate and BPH tissues.

METHODS

Normal prostate tissue samples (n = 4) were obtained from prostate biopsies of patients less than 40 years of age who underwent diagnostic cystoscopy for microscopic hematuria. Benign prostatic hyperplasia tissues (n = 12) were obtained from patients who underwent transurethral prostate resection for bladder outlet obstruction. The RNAs isolated from these tissue samples were analyzed with quantitative reverse transcriptase polymerase chain reaction; the proteins were analyzed with Western blotting and immunohistochemistry.

RESULTS

The mean NKX3.1 mRNA transcript expression was 19.17 +/- 3.05 vs 1.24 +/- 1.32 in BPH and normal tissues, respectively, and NKX3.1 protein expression of BPH was approximately 2.4-fold higher than in normal prostate tissue. Reverse transcriptase polymerase chain reaction and Western blot analyses revealed that NKX3.1 gene expression in BPH patient tissues were higher compared with normal prostate tissues. Immunohistochemistry results indicated that most of the BPH tissues stained diffusely, and there was no BPH tissue that lacked NKX3.1 expression.

CONCLUSIONS

NKX3.1 expression is elevated in BPH tissues when compared with normal tissues, which may be important in the development of BPH.