Steroid hormones and the pathogenesis of benign prostatic hyperplasia

Relationship between serum total testosterone and prostate volume in aging men

Total testosterone levels decline with age, while prostate volume and the prevalence of benign prostatic hyperplasia increase with age. We sought to investigate the correlation of serum testosterone levels with prostate volume in aging men. We analyzed clinical data obtained from 416 ostensibly healthy men who underwent routine health check-ups and recruited and collected data from these subjects 4 years later. We analyzed the correlation between prostate volume and relevant factors, as well as the correlation between changes in prostate volume and low testosterone over a 4-year period. Men with low testosterone had significantly larger prostate volume than those in the normal testosterone group (26.86 ± 8.75 vs. 24.06 ± 6.77 P = 0.02), and subjects with low testosterone had significantly higher levels of obesity-related factors, including waist circumference, body mass index, and insulin (all P < 0.001). After adjustment for age, testosterone level was negatively correlated with prostate volume (P = 0.004), and prostate volume and 4-year changes in prostate volume were associated with low testosterone. With increased testosterone level, prostate volume showed a significant linear decreasing trend. These findings provide evidence of the relationship between testosterone and prostate volume. Additional large studies are needed to confirm these preliminary results.

Efficacy and safety of dutasteride compared with finasteride in treating males with benign prostatic hyperplasia: A meta-analysis of randomized controlled trials

The present study was an updated meta-analysis that aimed to confirm the efficacy and safety of dutasteride (0.5 mg) and finasteride (5 mg) in treating males with benign prostatic hyperplasia (BPH) over a treatment period of at least 6 months. Randomized controlled trials were retrieved using the MEDLINE, EMBASE and the Cochrane controlled trials register databases. The references of the associated articles were also searched. A systematic review was performed by using the preferred reporting items for systematic reviews and meta-analyses. The data were analyzed with RevMan v5.3.0. A total of six articles including 2,041 participants were studied. The analysis demonstrated a significantly greater decrease in international prostate symptom score [IPSS; mean difference (MD), -0.86; 95% CI, -1.62 to -0.11; P=0.02] and prostate-specific antigen (PSA; MD, -0.13; 95% CI, -0.26 to -0.01; P=0.03) in the dutasteride group compared with that in the finasteride group, whereas no significant differences were observed in prostate volume (PV; P=0.64), maximum urine flow rate (Qmax; P=0.29) and post-void residual volume (PVRV; P=0.14). With regard to safety assessment, including any adverse event (P=0.66), decreased libido (P=0.39) and impotence (P=0.17), there was no significant difference between dutasteride and finasteride. In conclusion, in patients with BPH, dutasteride produced a greater decrease in IPSS and PSA compared with finasteride, whereas no significant differences were identified in PV, Qmax and PVRV. The two drugs appeared to have similar rates of adverse effects, particularly with regard to sexual dysfunction.

Meta-analysis of the efficacy and safety of combination of tamsulosin plus dutasteride compared with tamsulosin monotherapy in treating benign prostatic hyperplasia

Background

We performed a meta-analysis to confirm the efficacy and safety of the combination of tamsulosin plus dutasteride compared with tamsulosin monotherapy in treating benign prostatic hyperplasia (BPH) during a treatment cycle of at least 1 year.

Methods

Randomized controlled trials were searched by using MEDLINE, EMBASE, and the Cochrane Controlled Trials Register. Systematic review was carried out using the Preferred Reporting Items for Systematic Reviews and Meta-analyses. The data was evaluated and statistically analyzed by using RevMan version 5.3.0.

Results

Five studies including 4348 patients were studied. The analysis found that the combination group was significantly greater effect in international prostate symptom score (mean difference [MD], − 1.43; 95% confidence interval [CI], − 2.20 to − 0.66; P = 0.0003), prostate volume (MD, − 10.13; 95% CI, − 12.38 to − 7.88; P < 0.00001), transitional zone volume (MD, − 3.18; 95% CI, − 3.57 to − 2.79; P<0.0001), maximum urine flow rate (MD, 1.05; 95% CI, 0.82 to 1.29; P < 0.00001), prostate specific antigen (MD, − 0.54; 95% CI, − 0.80 to − 0.29; P < 0.0001) and post-void residual volume (MD, − 3.85; 95% CI, − 4.95 to − 2.76; P < 0.00001) compared with the tamsulosin group. In terms of safety, including adverse events (odds ratio [OR], 2.06; 95% CI, 1.34 to 3.17; P = 0.001), erectile dysfunction (OR, 2.24; 95% CI, 1.73 to 2.92; P < 0.00001), ejaculation disorder (OR, 3.37; 95% CI, 1.97 to 5.79; P < 0.0001), retrograde ejaculation (OR, 2.30; 95% CI, 1.08 to 4.93; P = 0.03), decreased libido (OR, 2.25; 95% CI, 1.53 to 3.31; P < 0.0001) and loss of libido (OR, 3.38; 95% CI, 1.94 to 5.88; P<0.0001), the combination group showed poor tolerance than the tamsulosin group with the exception of dizziness (OR, 1.16; 95% CI, 0.75 to 1.80; P = 0.50). The combination group significantly reduced the risk of clinical progression than the tamsulosin group especially in incidence of BPH-related symptom progression (OR, 0.56; 95% CI, 0.46 to 0.67; P < 0.00001) and acute urinary retention (OR, 0.61; 95% CI, 0.38 to 0.98; P = 0.04).

Conclusion

The combination of tamsulosin plus dutasteride provides a preferable therapeutic effect for BPH with a higher incidence of sexual side effects, but combination-therapy can markedly reduce risk of BPH-related symptom progression and acute urinary retention relative to tamsulosin monotherapy.

A possible relationship between serum sex hormones and benign prostatic hyperplasia/lower urinary tract symptoms in men who underwent transurethral prostate resection

In this study, we examined the relationship between sex hormone levels and lower urinary tract symptoms (LUTS) in men with benign prostatic hyperplasia (BPH) who underwent transurethral surgery. The study was conducted in 158 patients who came to our hospital for surgery. Clinical conditions were assessed by body mass index (BMI), digital rectal examination, International Prostate Symptom Score (IPSS) and transrectal ultrasound (TRUS). The levels of sex hormones (including total testosterone (TT), estradiol (E₂), progesterone (P), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and prolactin (PRL)) and prostate-specific antigen (PSA) were reviewed. Correlations were determined through statistical analysis. The mean age was 72.06 ± 8.68 years. The total IPSS was significantly associated with the TT level (r = −0.21, P= 0.01). Other sex hormone levels were not correlated with total IPSS. However, some ratios such as E₂/TT (r = 0.23, P= 0.00) and FSH/LH (r = −0.17, P = 0.04) were associated with total IPSS. Further analysis showed that the nocturia was associated with age (r = 0.16, P= 0.04), BMI (r = 0.21, P = 0.01), and TT (r = −0.19, P= 0.02). Moreover, we divided the patients into two subgroups based on IPSS severity (<20 or ≥20). The mean TT level was in the normal range, but it was significantly related to the presence of severe LUTS. In summary, our study has shown that the severity of LUTS is associated with TT, E₂/TT and FSH/LH in men who underwent prostate surgery. Increasing nocturia was observed in lower testosterone patients. Additional larger studies are needed to elucidate the potential mechanisms.

Do baseline estrogen and testosterone affect lower urinary tract symptoms (LUTS) prior to or after pharmacologic treatment with tadalafil?

Little is known about how total testosterone and estradiol-17β influence lower urinary tract symptoms (LUTS) in men with benign prostatic hypertrophy (BPH). We analyzed data from a subset of men aged ≥18 years randomized to tadalafil 5 mg once-daily or placebo who had ≥6 month history of LUTS and an International Prostate Symptom Score (IPSS)≥13 enrolled in one of three randomized, placebo-controlled tadalafil clinical trials (N = 958). Three specific aims were addressed, as follows: (i) To characterize enrolled men by treatment randomization and testosterone level; (ii) to assess cross-sectional associations of estradiol-17β, testosterone, and LUTS prior to treatment with tadalafil; and, (iii) to assess longitudinal associations between baseline estradiol-17β and testosterone and improvements or worsening of LUTS during a 12-week period of tadalafil or placebo administration. LUTS were assessed by total IPSS, IPSS voiding sub-score (IPSS-V) and IPSS storage sub-score (IPSS-S) for cross-sectional analyses, and change in total IPSS (ΔIPSS), ΔIPSS-V, and ΔIPSS-S between baseline and 12-week visit for longitudinal analyses. Correlation analyses and linear regression examined associations. Baseline testosterone was not significantly associated with IPSS. In contrast, estradiol-17β was inversely correlated with IPSS (r = -0.08; p < 0.05) and IPSS-S (r = -0.14; p < 0.05). Tadalafil treatment resulted in greater IPSS improvements in men with lower baseline estradiol-17β versus those with higher baseline estradiol-17β. Lower baseline estradiol-17β was significantly associated with modestly improved ΔIPSS-V (p = 0.04) and Δtotal IPSS (p = 0.05) but not with ΔIPSS-S, following treatment which may substantiate the role of bladder dysfunction because of nerve and smooth muscle changes in the bladder in addition to benign prostatic enlargement in LUTS. Circulating baseline testosterone did not predict ΔIPSS. Men with lower baseline estradiol-17β levels showed greater responsiveness to tadalafil 5 mg treatment than those with higher baseline estradiol-17β levels when responsiveness was measured using total IPSS and IPSS-V.

Proteomic analysis of patient tissue reveals PSA protein in the stroma of benign prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) is an age-related disease frequently associated with lower urinary tract symptoms (LUTS) that involves hyperplasia of both epithelial and stromal cells. Stromal fibrosis is a distinctive feature of BPH, but the exact mechanisms underlying this phenomenon are poorly understood.

METHODS

In the current study, proteomics analyses were utilized to identify proteins altered in the BPH stromal compartment from patients with symptomatic BPH. Stromal cells were isolated from histological nodules of BPH by laser capture microdissection (LCM) and subjected to liquid chromatography/mass spectrometry.

RESULTS

Proteins identified included several stromal-specific proteins involved in extracellular matrix (ECM) remodeling, focal adhesion, and cellular junctions. Additionally, the proteomics array identified the presence of luminal epithelial secretory protein PSA. Immunostaining, ELISA, and in situ hybridization analyses of BPH tissues verified the presence of PSA protein but absence of PSA mRNA in the stromal compartment. E-cadherin was down-regulated in BPH epithelial cells compared to normal adjacent tissues, suggesting that alteration of cellular junctions could contribute to the presence of luminal epithelial secreted proteins PSA and KLK2 in the stromal compartment.

CONCLUSIONS

The above findings suggest that the presence of secreted proteins PSA and KLK2 from prostate luminal epithelial cells in BPH stroma is a hallmark of BPH nodules, which could in part be due to alterations in cellular junction proteins and/or increased epithelial barrier permeability. Elucidating the cause and consequence of these secreted proteins in the stromal compartment of BPH may lead to new understanding of BPH pathogenesis as well as approaches to prevent and/or treat this common disease.

Gene Expression Profiling Reveals Regulation of ERK Phosphorylation by Androgen-Induced Tumor Suppressor U19/EAF2 in the Mouse Prostate

U19/EAF2 is regulated by androgens in the prostate and capable of regulating transcriptional elongation of RNA Pol II via interaction with the ELL family proteins. Inactivation of U19/EAF2 induces tumorigenesis in multiple organs; however the mechanism of U19/EAF2 tumor suppression remains unclear. To elucidate potential mechanisms of U19/EAF2 action, we performed cDNA microarray analysis and identified 164 mRNA transcripts regulated by U19/EAF2 in the mouse ventral prostate. Bioinformatics analysis indicated that U19/EAF2 knockout activates the RAS-BRAF-ERK signaling pathway, which is known to play important roles in carcinogenesis. qPCR verified increased expression of BRAF mRNA, and immunostaining and Western blot analysis demonstrated increased expression of p-ERK at the protein level suggested U19/EAF2 knockout activates this important pathway. These findings indicate that loss of EAF2 up-regulates transcription of RAS cascade genes including Grb2, PI3K, and BRAF, leading to elevated p-ERK levels, which may represent a major functional role of U19/EAF2 in the prostate. Furthermore, these observations suggest that U19/EAF2 is a key player in crosstalk between androgen receptor and the RAS-BRAF-ERK signaling pathway.

Relationship of sex hormones and nocturia in lower urinary tract symptoms induced by benign prostatic hyperplasia

OBJECTIVE

The study sought to clarify the relationship between sex hormone levels and lower urinary tract symptoms (LUTS) in patients with benign prostate hyperplasia.

METHODS

Between 2007 and 2010, serum total testosterone (TT), free testosterone, and estradiol were prospectively measured in patients who were transferred to our university hospital. The 924 subjects were divided into two groups. Group I (n = 646) were treated with an alpha blocker only and group II (n = 278) were treated with an alpha blocker + a 5-alpha reductase inhibitor over 3 months before their visit. Clinical conditions were assessed by digital rectal examination, prostate-specific antigen, International Prostate Symptom Score (IPSS), transrectal ultrasonography and maximum urinary flow rate and postvoid residual urine.

RESULTS

The mean age was 69.65 ± 6.56 years. The total IPSS and subscore (storage symptom) was significantly associated with age (p < 0.001/p < 0.05) and the TT level (p < 0.05/p < 0.05). TT level was significantly decreased in patients with ≥ 4 episodes of nocturia. The TT level was significantly related to the presence of severe LUTS (p < 0.05).

CONCLUSIONS

Endogenous testosterone may have a beneficial effect on lower urinary tract function and that a high frequency of nocturia may induce testosterone deficiency.

Significant association between serum dihydrotestosterone level and prostate volume among Taiwanese men aged 40-79 years

INTRODUCTION

We evaluated the association between serum sex hormone levels and prostate volume in Taiwanese men.

METHODS

A cross-sectional study was conducted in 505 men (aged 40-79 years, mean age 58 years). Serum total testosterone (TT), free testosterone (FT), dihydrotestosterone (DHT) and estradiol (E2) levels were measured. Total prostate volume (TPV) and transition zone volume (TZV) were measured by transrectal ultrasonography. Body mass index (BMI), DHT/TT and E2/TT were calculated. Correlations were determined using univariate and multivariate regression analyses.

RESULTS

Apart from DHT, an age-dependent change of sex hormone levels were observed. On univariate analyses, age, BMI, serum DHT level and DHT/TT ratio, as well as serum E2 level and E2/TT ratio, but not serum TT and FT levels showed a significant association with prostate volume. On multivariate analysis, however, only serum DHT level and DHT/TT ratio remained significant. Logistic regression analysis showed that the odds ratios (95% confidence interval) of the second, third, and fourth quartiles of serum DHT levels for benign prostatic hyperplasia (defined as TPV ≥ 20 ml) risk were 2.06 (1.21-3.51), 2.66(1.56-4.53) and 7.15(4.0-12.6), respectively (p < 0.001).

CONCLUSIONS

Higher serum DHT level and DHT/TT ratio were associated with larger prostate volume and higher prevalence of BPH in Taiwanese men.

Role of insulin and testosterone in prostatic growth: who is doing what?

Previous studies have demonstrated increased incidence of benign prostatic hyperplasia in insulin-resistant individuals. In addition to androgens, prostatic growth is sensitive to the peptide growth factors including insulin. Experimental studies employing intervention of selective β-cell toxin streptozotocin and castration suggest that depletion of either insulin or testosterone results in the severe prostatic atrophy (>80%). Exogenous testosterone and diet-induced experimental hyperinsulinemia induces prostatic enlargement in rats. Further, hyperinsulinemia sensitizes prostate towards the growth promoting effect of testosterone, and testosterone augments prostatic growth even in the hypoinsulinemic rats. However, in castrated rats diet-induced hyperinsulinemia fails to promote prostatic growth. Based on these evidences it is hypothesized that in the presence of testosterone insulin plays an important role in the prostatic growth. The epidemiological reports witnessing increased incidences of prostatic enlargement in men with metabolic syndrome, which are known to have increased level of insulin, provides a validating clue to the hypothesis. Further, the hypothesis suggests that targeting insulin signaling pathway could be a new objective for the treatment of prostatic enlargement.

PTPIP51 mRNA and protein expression in tissue microarrays and promoter methylation of benign prostate hyperplasia and prostate carcinoma

BACKGROUND

Protein tyrosine phosphatase interacting protein 51 (PTPIP51) shows a tissue-specific expression pattern and is associated with cellular differentiation and apoptosis in several mammalian tissues. Overexpression of the full-length protein enhances apoptosis. It is also expressed in various carcinomas. In this study the expression of PTPIP51 and its in vitro interaction partners was investigated in human benign prostate hyperplasia (BPH) and in prostate carcinoma (PCa).

METHODS

Tissue microarrays of human BPH and PCa were analyzed by immunohistochemistry. For polymerase chain reaction (PCR), cryo samples of BPH and PCa were used. Bisulfite DNA treatment, followed by sequencing of PCR products was performed in order to analyze CpGs methylation within the promoter region of the PTPIP51 gene.

RESULTS

PTPIP51 mRNA and protein expression was detected in prostatic epithelia of BPH and in tumor cells of PCa, respectively, and within smooth muscle cells of the stromal compartment. A stronger expression was present in nerve fibers, particularly in PCa, in immune cells and in smooth muscle and endothelial cells of vessels of BPH and PCa. On mRNA levels, a slightly elevated expression of PTPIP51 was observed in the PCa group as tested by real-time quantitative PCR analyses. Methylation experiments revealed that at least 70% of methylated CpGs in the CpG island of the PTPIP51 gene promoter region were identified in BPH samples. In contrast, a loss of methylation has been found in the PCa group.

CONCLUSION

The promoter methylation status of PTPIP51 seems to influence the expression of PTPIP51, which was seen as elevated in the PCa.

Effects of mepartricin, a polyene macrolide antibiotic, on estrogen-induced hyperplastic growth of the dorsolateral prostate and seminal vesicle in immature castrated rats

OBJECTIVE

To investigate the effects of mepartricin, a polyene macrolide antibiotic, on estrogen-induced hyperplastic prostate and seminal vesicle (SV) growth in castrated rats.

MATERIAL AND METHODS

Immature rats aged 3 weeks were castrated and left untreated for 1 week. Then, 17beta-estradiol benzoate (E(2)-BA) was subcutaneously injected at a dose of 10 microg/day twice weekly, and mepartricin was orally administered at doses of 2.5, 5 and 10 mg/kg once daily for 3 weeks. The weights and hydroxyproline contents of the prostate and SV, the activity of growth factors (GFs) in the dorsolateral prostate (DLP) and the serum estrogen level were measured. Histological examination of the prostate and SV was also performed.

RESULTS

Mepartricin dose-dependently suppressed the increase in the serum estrogen level, the weights and hydroxyproline contents of the DLP and SV and the elevation of GF activity in the DLP induced by E(2)-BA treatment. Histological examination also revealed that treatment with mepartricin reduced collagen accumulation and thickening of the smooth muscle layer in the DLP and SV, and proliferation of the glandular epithelium in the DLP.

CONCLUSIONS

These results suggest that mepartricin suppresses hyperplastic growth of the DLP and SV induced by estrogen in immature castrated rats, the underlying mechanism being a reduction in the serum estrogen level, thereby suppressing stromal cell proliferation and activation.

Relationship of serum sex-steroid hormones and prostate volume in African American men

BACKGROUND

Previous epidemiologic investigations of the associations of sex-steroid hormones and benign prostatic hyperplasia (BPH) have focused on predominately white populations. The objective of this study was to evaluate potential associations of body mass index (BMI), cigarette smoking, use of alcohol, and endogenous sex-steroid hormones with prostate volume in a population-based sample of African American (AA) men, ages 40-79 yr.

METHODS

A total of 369 AA men without clinical evidence of prostate cancer were identified in the Flint Men's Health Study by using a population-based sampling procedure. All subjects underwent a complete urologic evaluation that included prostate volume determination by transrectal ultrasonography and serum assays for androgens and estrogens.

RESULTS

After age adjustment, BMI (weight (kg)/height (m)2) was positively correlated with increasing levels of androstanediol glucuronide (AG), estradiol (E2), estrone sulfate (E1S), and the ratios of E2:total testosterone (TT) and E2:free testosterone (FT); however, increasing BMI was negatively correlated with androstenedione (AD), FT, TT, and sex hormone-binding globulin (SHBG). Multivariable regression models demonstrated that prostate volume increased with age (P < 0.001) and BMI (P = 0.02) and decreased with increasing levels of SHBG (P = 0.01). Larger prostatic volumes were also marginally associated with increasing levels of TT (P = 0.058).

CONCLUSION

Circulating serum levels of SHBG and endogenous sex-steroid hormones are correlated with prostate volume and potentially impact the natural history of BPH. However, longitudinal studies are needed to demonstrate the temporal relationships of hormones and growth factors in the pathogenesis of BPH in AA men.

Impact of radical prostatectomy and TURP on the hypothalamic-pituitary-gonadal hormone axis

OBJECTIVES

To assess the impact of prostate cancer (PCa) and benign prostatic hyperplasia (BPH) on the hypothalamic-pituitary hormone axis, we determined the endocrine changes after radical prostatectomy (RP) and transurethral resection of the prostate (TURP) for BPH and in a group of men with BPH followed up conservatively.

METHODS

Patients with PCa before RP (n = 49), those who underwent TURP for BPH (n = 51), and men with lower urinary tract symptoms for whom a wait-and-see strategy was chosen (n = 46) were included. Serum levels of total testosterone, luteinizing hormone, and follicle-stimulating hormone were determined at baseline and 6 and 12 months later in all patients.

RESULTS

No significant endocrine changes were observed in the wait-and-see and TURP groups 6 and 12 months after baseline. In contrast, luteinizing hormone increased from 5.2 to 8.9 mIU/mL (P = 0.0004) and follicle-stimulating hormone from 5.7 to 9.3 mIU/mL (P = 0.0003) 12 months after RP. The rise of total testosterone from 3.9 to 4.4 ng/mL failed to reach statistical significance (P = 0.18). Patients with Gleason score 2 to 6 PCa had higher testosterone values (4.2 ng/mL) at baseline than did those with Gleason score 7 to 10 PCa (2.2 ng/mL, P < 0.05). Although 12 months after RP no changes in testosterone were observed in the low Gleason score group, the testosterone levels more than doubled in those with high-grade tumors. The increases in luteinizing hormone and follicle-stimulating hormone at 12 months, however, were comparable in both groups.

CONCLUSIONS

Our findings suggest a significant impact of PCa on the hypothalamic-pituitary axis that is more profound in high-grade cancer. Such an effect was not demonstrable for the transition zone in BPH.

Pharmacokinetics and pharmacodynamics of TF-505, a novel nonsteroidal 5alpha-reductase inhibitor, in normal subjects treated with single or multiple doses

AIMS

To assess the tolerability, pharmacokinetics and pharmacodynamics of a novel nonsteroidal and noncompetitive inhibitor of type I and type II 5alpha-reductases, (-)-(S)-4-[1-[4-[1-(4-isobutylphenyl) butoxy]benzoyl]indolizin-3-yl]butyric acid (TF-505), after single and multiple oral doses in healthy volunteers.

METHODS

In the single-dose study, six young adult males in each dose group received 25 mg or 50 mg of TF-505, and six older males (>or= 40 years) in each dose group received 75 mg or 100 mg of TF-505. The subjects were given the drug in ascending dose and in the fasting state. Six subjects also received 50 mg of TF-505 after breakfast in a two-period crossover manner. In the multiple-dose study, six older males in each dose group received 12.5 mg or 25 mg TF-505 after breakfast daily for 7 days. Plasma concentrations of TF-505, dihydrotestosterone (DHT) and testosterone were measured. The pharmacokinetics of TF-505 were analysed by a compartment model with first-order absorption, first-order elimination and a lag time. Pharmacokinetic and pharmacodynamic relationships were evaluated by indirect response modelling with inhibition of input.

RESULTS

Maximum plasma concentration (Cmax) and the area under the concentration-time curve (AUC) increased proportionately after the single dose up to 50 mg and with the multiple doses. Linearity was not detected between 75 and 100 mg of TF-505. Dose dependency was also noted for the effect of TF-505 on DHT concentrations following single doses up to 50 mg and multiple doses. Plasma DHT concentrations decreased maximally to 58.2, 49.5, 54.2 and 49.8% of basal values at 8-12 h after single administration of 25, 50, 75 and 100 mg TF-505, respectively, and to 60.5 and 49.4% at the 7th and 5th dose following multiple doses of 12.5 and 25 mg TF-505, respectively. The predicted effect curves matched the observed data when the indirect response model was applied to the time course of the suppressant effect of TF-505 on plasma DHT concentrations after both the single and multiple studies. Fifty percent inhibitory concentrations (IC50) of 0.82, 1.48, 1.31 and 0.88 micro g ml(-1), zero-order rate constants for the onset of plasma DHT concentration changes (kin) of 17.8, 17.4, 17.0 and 10.7% h(-1) and first-order rate constants for increase in plasma DHT concentrations to basal values (kout) of 0.17, 0.16, 0.17 and 0.10 h(-1) for the single study at doses of 25, 50, 75 and 100 mg, respectively, were attained. In the multiple-dose study, IC50s were 1.74 and 1.49 micro g ml(-1) for the 12.5 and 25 mg doses, respectively. No serious adverse events related to TF-505 were observed.

CONCLUSIONS

TF-505 was well tolerated in healthy male volunteers. Accumulation of TF-505 in plasma was not observed during multiple dosing. The indirect response model described the relationships between pharmacokinetics and pharmacodynamics of TF-505. Such modelling is expected to yield an appropriate dosage regimen in subsequent clinical trials.

Regulation of male sex hormone levels by soy isoflavones in rats

Several studies have suggested that soybean intake is associated with a lower risk of prostate cancer. However, the mechanism of prostate cancer prevention by soybeans remains unclear. Because prostate cancer is reported to have an association with an increased level of dihydrotestosterone (DHT) and soybean isoflavones are known to inhibit 5 alpha-reductase, which is involved in the conversion of testosterone to DHT, the effects of soybean extract and isoflavones on the plasma levels of male sex hormones were investigated using male rats. In Experiment I, Sprague-Dawley rats were fed diets with and without soy flour; in Experiment II, rats were fed diets containing 2% soy methanol extract or 0.2% semipurified isoflavones or a control diet. The study showed a reduction of plasma DHT along with an increase in total plasma androgen in rats fed soy flour or semipurified isoflavones for 1 wk. These results suggest that soy isoflavone intake may reduce plasma DHT level.

Risk factors for clinical benign prostatic hyperplasia in a community-based population of healthy aging men

We defined risk factors for a clinical diagnosis of benign prostatic hyperplasia (BPH) among subjects of the population-based Massachusetts Male Aging Study. In 1987-89 1709 men aged 40-70 provided baseline risk factor data and were followed for a mean of 9 years; 1019 men without prostate cancer provided follow-up data. We classified men with clinical BPH at follow-up if they reported (1) frequent or difficulty urinating and were told by a health professional that they had an enlarged or swollen prostate or (2) if they reported having surgery for BPH. At follow-up the prevalence of clinical BPH was 19.4%, increasing from 8.4% of men aged 38-49 years to 33.5% of men aged 60-70 years (P < 0.001 for trend). Elevated free PSA levels (age- and total PSA-adjusted OR, top vs. bottom quartile ng/mL 4.4, 95% CI 1.9-10.5), heart disease (age-adjusted OR 2.1, CI 1.3-3.3), and use of beta-blocker medications (OR 1.8, CI 1.1-3.0) increased odds for BPH, while current cigarette smoking (OR 0.5, CI 0.3-0.8) and high levels of physical activity (top vs. bottom quartile kcals/day OR 0.5, CI 0.3-0.9) decreased odds of BPH. All but the medication effects persisted in fully adjusted multivariable models. Total or fat calorie intake, sexual activity level, alcohol intake, body mass index, waist-hip ratio, diastolic blood pressure, a history of diabetes, hypertension, vasectomy, or serum levels of androgens or estrogens did not individually predict clinical BPH. We conclude that physical exercise and cigarette smoking appear to protect against development of clinical BPH. Elevated free PSA levels predict clinical BPH independent of total PSA levels. Risk associated with heart disease does not appear to be due solely to detection bias or to effects of heart disease medications. A wide variety of other characteristics appear to have no influence on risk for clinical BPH.

Effects of mepartricin on estradiol and testosterone serum levels and on prostatic estrogen, androgen and adrenergic receptor concentrations in adult rats

The effects induced by oral administration of 0, 5 and 20 mg of meparticin kg(-1)of body weight for 28 days (group 1, 2 and 3, respectively) upon prostatic estrogen, androgen, alpha(1)- and beta-adrenergic receptor concentrations and on estradiol and testosterone serum levels in adult male rats were studied. The effects produced by mepartricin treatments on the weight and dimension of the gland were investigated. Both mepartricin dosages induced significant decreases (P< 0.05) of the absolute and relative weights and of the dimensions of the prostate. A significant dose-dependent decrease (P< 0.05) in estradiol serum levels was observed in treated rats, whereas no significant modifications were found in testosterone serum levels. As far as prostatic steroid receptor concentrations were concerned, a significant (P< 0.05) decrease in estrogen receptor number was observed in both treated groups, whilst a significant increase (P< 0.05) of androgen receptor concentrations was recorded only in rats treated with 20 mg mepartricin kg(-1). Conversely, a dose-dependent up-regulation of both prostatic alpha(1)- and beta-AR was found. Data obtained suggest that the prostatic alpha(1)-AR expression may be strongly influenced by estrogen deprivation (mepartricin treatment), therefore the combination of estrogen suppression (mepartricin) and adrenergic suppression (alpha(1)-AR blockers) may be suggested as a possible pharmacotherapeutic strategy for the treatment of benign prostatic hyperplasia.

Ornithine decarboxylase activity and its gene expression are increased in benign hyperplastic prostate

BACKGROUND

Ornithine decarboxylase (ODC) is the first key enzyme in the polyamine biosynthesis pathway. Polyamine is believed to participate in cellular proliferation and differentiation. To study the relationship between ODC and the pathogenesis of benign prostatic hyperplasia (BPH), the polyamine levels, ODC activities, and expression of ODC mRNA in benign hyperplastic and normal human prostates were assayed.

METHODS

Polyamine contents and ODC activities in tissue extracts were determined by reverse-phase high-performance liquid chromatography and spectrophotometric procedures, respectively. The ODC mRNA levels were assayed by Northern blot analysis.

RESULTS

The contents of putrescine, spermidine, and spermine in BPH tissues were 2.2, 3.4, and 6.0 times higher than those in normal tissues, respectively; the ODC activity of BPH tissue was about 3.2 times higher than in normal tissue; the expression level of ODC mRNA in the BPH tissues was greater than that of normal tissues.

CONCLUSIONS

The findings imply that 1) the increased ODC activity and polyamine content in prostatic tissue may correlate with the pathogenesis of BPH, and 2) the high level of ODC activity is induced by the overexpression of ODC mRNA.

Endocrine status in elderly men with lower urinary tract symptoms: correlation of age, hormonal status, and lower urinary tract function. The Prostate Study Group of the Austrian Society of Urology

OBJECTIVES

To correlate endocrine parameters in elderly men with lower urinary tract symptoms (LUTS) to patient age and clinical parameters such as prostate volume, prostate-specific antigen (PSA) levels, and uroflowmetry and to compare the clinical and endocrinologic parameters in men with or without hypogonadism.

METHODS

Men (40 years old or older) with untreated LUTS as defined by an International Prostate Symptom Score (IPSS) of 7 or greater due to benign prostatic hyperplasia were included in this study and underwent the following investigations: IPSS, free uroflow study, postvoid residual volume, transrectal ultrasound for assessment of prostate volume, serum PSA determination, and an endocrine study, including testosterone, human luteinizing hormone, human follicle-stimulating hormone, prolactin, dehydroepiandrostendione-sulphate (DHEA-S), and prolactin.

RESULTS

Three hundred twelve men (mean age 62.8 +/- 10.6 years, range 40 to 91) were analyzed. The serum levels of estradiol (correlation coefficient [r] = 0.19), human luteinizing hormone (r = 0.32), human follicle-stimulating hormone (r = 0.19), and DHEA-S (r = -0.39) correlated (P <0.05) with age; no such correlation was seen for testosterone (r = 0.04; P0.05) or prolactin (r = 0.09; P0.05). Estradiol (but not testosterone) correlated (r = 0.17, P = 0.01) with prostate volume. The peak flow rate and PSA did not correlate with any endocrinologic parameter. Hypogonadism (serum testosterone less than 3.0 ng/mL) was detected in 22.1% of patients and had no impact on clinical (IPSS, peak flow rate, prostate volume, and PSA level) or endocrine (human luteinizing hormone, human follicle-stimulating hormone, estradiol, prolactin, and DHEA-S) parameters.

CONCLUSIONS

A number of age-related endocrine changes are seen in elderly men with LUTS. Hypogonadism is seen in approximately one fifth of elderly men with LUTS, but in our study it had no impact on symptom status, PSA level, prostate volume, uroflowmetry, or endocrine parameters.

Effects of mepartricin, a polyene macrolide agent, on fecal excretion and serum concentration of estrogen and number of prostatic estrogen receptors in immature rats

BACKGROUND

Mepartricin, an antifungal agent, was investigated for effects on fecal excretion and serum concentration of sex steroids and the number of sex steroid prostatic receptors in immature rats.

METHODS

Mepartricin was orally administered at 2.5, 5, and 10 mg/kg once daily for 2 weeks. Fecal estrogen and testosterone excretions, serum estrogen, testosterone and luteinizing hormone concentrations, and numbers of prostatic estrogen and androgen receptors were assayed. Prostate weight was also monitored.

RESULTS

Fecal estrogen excretion showed a dose-dependent increase, which was significant for the two higher dosages. Conversely, the serum estrogen concentration and prostatic estrogen receptors were significantly decreased. No significant changes in fecal testosterone excretion, serum testosterone and luteinizing hormone concentrations, and prostatic androgen receptors were observed. Prostate weight was significantly reduced at 5 mg/kg, but we did not observe dose-dependency.

CONCLUSIONS

Mepartricin increases fecal excretion of estrogen by binding with it in the intestinal tract, which results in reducing the serum estrogen concentration and number of prostatic estrogen receptors.

Effect of exogenous testosterone on prostate volume, serum and semen prostate specific antigen levels in healthy young men

PURPOSE

We investigate and define the effects of exogenous testosterone on the normal prostate.

MATERIALS AND METHODS

A total of 31 healthy volunteers 21 to 39 years old were randomized to receive either 100, 250 or 500 mg. testosterone via intramuscular injection once a week for 15 weeks. Baseline measurements of serum testosterone, free testosterone and prostate specific antigen (PSA) were taken at week 1. Semen samples were also collected for PSA content and prostate volumes were determined by transrectal ultrasound before testosterone injection. Blood was then drawn every other week before each testosterone injection for the 15 weeks, every other week thereafter until week 28 and again at week 40. After the first 15 weeks semen samples were again collected, and prostate volumes were determined by repeat transrectal ultrasound.

RESULTS

Free and total serum testosterone levels increased significantly in the 250 and 500 mg. dose groups. No significant change occurred in the prostate volume or serum PSA levels at any dose of exogenous testosterone. Total semen PSA levels decreased following administration of testosterone but did not reach statistical significance.

CONCLUSIONS

Despite significant elevations in serum total and free testosterone, healthy young men do not demonstrate increased serum or semen PSA levels, or increased prostate volume in response to exogenous testosterone injections.

Comparison of phytotherapy (Permixon) with finasteride in the treatment of benign prostate hyperplasia: a randomized international study of 1,098 patients

BACKGROUND

Controversy regarding the relative efficacy of treatments for the relief of the symptoms of benign prostatic hyperplasia (BPH).

METHODS

This was a 6-month double-blind randomized equivalence study that compared the effects of a plant extract (320 mg Permixon) with those of a 5 alpha-reductase inhibitor (5 mg finasteride) in 1,098 men with moderate BPH using the International Prostate Symptom Score (IPSS) as the primary end-point.

RESULTS

Both Permixon and finasteride decreased the IPSS (-37% and -39%, respectively), improved quality of life (by 38 and 41%), and increased peak urinary flow rate (+25% and +30%, P = 0.035), with no statistical difference in the percent of responders with a 3 ml/sec improvement. Finasteride markedly decreased prostate volume (-18%) and serum PSA levels (-41%); Permixon improved symptoms with little effect on volume (-6%) and no change in PSA levels. Permixon fared better than finasteride in a sexual function questionnaire and gave rise to less complaints of decreased libido and impotence.

CONCLUSIONS

Both treatments relieve the symptoms of BPH in about two-thirds of patients but, unlike finasteride, Permixon has little effect on so-called androgen-dependent parameters. This suggests that other pathways might also be involved in the symptomatology of BPH.

Effect of prostatic growth factor, basic fibroblast growth factor, epidermal growth factor, and steroids on the proliferation of human fetal prostatic fibroblasts

To study the relationship between androgen metabolism and the pathogenesis of benign prostatic hypertrophy, we purified a growth factor from benign hyperplastic tissue of human prostates and assayed the proliferative responses of human fetal prostatic fibroblasts to the purified growth factor (hPGF), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), dihydrotestosterone (DHT), and estradiol (E2). Prostatic tissue extracts were fractionated using heparin-Sepharose chromatography. The fraction that eluted with 1.3-1.7 M NaCl contained the majority of mitogenic activity. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS/PAGE) of the lyophilyzed active fraction showed a band at 17,000 daltons. Human prostatic fibroblasts were isolated from fetal prostate and tested for their proliferative responses to hPGF, bFGF, EGF, DHT, and E2. hPGF, as well as bFGF and EGF, did increase tritiated thymidine incorporation into the cultured fibroblasts. DHT(10(-7) M) had a significant stimulatory effect on cell growth in serum-free media after 6 days of culture. E2(10-7 M) had no effect on cell proliferation. The combination of DHT and E2 showed no synergistic effect. We conclude that our purified hPGF, bFGF, and EGF promote cell growth directly, DHT indirectly, while E2 does not. The effect of DHT appears to be mediated via the increased production and/or secretion of growth factor(s). Possibly, the bFGF-like hPGF purified from human benign hyperplastic prostatic tissue is such a mediator.

Determination of oenothein B as the active 5-alpha-reductase-inhibiting principle of the folk medicine Epilobium parviflorum

Several extracts from Epilobium parviflorum, a plant used in Central Europe for the treatment of prostate disorders, were evaluated in a biochemical assay with 5-alpha-reductase. The aqueous extract displaying inhibition of the enzyme was analyzed, the fraction responsible for this activity was purified, and the active compound identified as a macrocyclic tannin, oenothein B (1).

Effects on the endocrine system of long-term treatment with the non-steroidal anti-androgen Casodex in patients with benign prostatic hyperplasia

OBJECTIVE

To study the hormonal changes resulting from long-term use of the non-steroidal anti-androgen Casodex.

PATIENTS AND METHODS

A randomized, placebo-controlled study was carried out on 27 patients with benign prostatic hyperplasia (BPH). Fourteen patients received Casodex 50 mg daily for 24 weeks and 13 received a placebo. The patients were followed up for a further 24-week period.

RESULTS

Serum concentrations of luteinizing hormone (LH) increased by an average of 40% while follicle-stimulating hormone (FSH) remained unchanged. Testosterone increased by 35%, oestradiol by 29% and oestrone by 23%; all changes were statistically significant. Levels of androstenedione and dihydrotestosterone increased by 11% and 15%, respectively, but these increases did not reach statistical significance. A non-significant increase was also observed for sex hormone-binding globulin. The hormonal changes were reversible upon discontinuation of therapy. Prolactin and dehydroepiandrosterone-sulphate levels did not change.

CONCLUSION

This study indicates that Casodex, due to competitive inhibition of central androgen receptors, increases LH secretion, thus causing increased production and increased metabolism of testosterone.

The detachment cascade during metastasis

The cause of detachment of tumour cells during metastasis is still one of the most intriguing questions of tumour propagation. A hypothesis is suggested herein for lysis of extracellular matrix that could ultimately lead to the detachment and spreading of malignant cells. According to this theory a certain optimal estrogen level initiates a series of enzymatic activations that culminate in detachment and spreading of tumour cells.