Prostate tissue composition and response to finasteride in men with symptomatic benign prostatic hyperplasia

PURPOSE: We sought to quantify prostate tissue changes induced by finasteride and to identify a predictor of finasteride response in men with symptomatic benign prostatic hyperplasia (BPH) via a randomized, placebo controlled, double-blind clinical trial. MATERIALS AND METHODS: Men with symptomatic BPH (52 to 78 years old) were randomly assigned to 6 months of treatment with finasteride (26) or placebo (15). Outcome measures were clinical (urinary symptom score and flow rate), chemical (serum prostate specific antigen and dihydrotestosterone levels), volumetric (transrectal ultrasound, and magnetic resonance imaging for whole and zonal prostate volumes) and histological (morphometry of prostate sextant biopsies, separated into inner and outer gland segments, to measure the percent epithelium, stroma and glandular lumen). RESULTS: In the finasteride group we found a suggestion of decreasing symptom scores and increasing flow rates (not significant) with significant decreases (p < 0.01) in prostate specific antigen (48%), dihydrotestosterone (74%) and prostate volume (21%). Finasteride treatment induced a 55% decrease in inner gland epithelium (p < 0.01) with little effect on stroma or lumina. We also found a linear correlation between pretreatment inner gland epithelial content and prostate volume decrease induced by the drug (tau = 0.58, p = 0.01). CONCLUSIONS: Finasteride treatment results in a major suppression of prostate epithelium, which is most pronounced in the inner gland. Moreover, a finasteride induced prostate volume decrease was predictable by quantification of epithelial tissues of the inner gland. These data lend additional support to the emerging concept of transition zone primacy in symptomatic BPH.     

Plasma androsterone/epiandrosterone sulfates as markers of 5 alpha-reductase activity: effect of finasteride in normal men

Plasma androsterone/epiandrosterone sulfates, dehydroepiandrosterone sulfate, dihydrotestosterone, testosterone, androstenedione, and cortisol were measured in three normal adult men before and following finasteride administration (5 mg/day). Plasma androsterone/epiandrosterone sulfates and dihydrotestosterone declined in parallel to 50% of basal levels with little change in either dehydroepiandrosterone sulfate, cortisol, or androstenedione. The results suggest that the direct measurement of plasma androsterone/epiandrosterone sulfates by enzyme-linked immunosorbent assay provide similar information to plasma dihydrotestosterone and therefore provide a simple alternative for the assessment of 5 alpha-reductase activity.     

Drug treatment of prostatic carcinoma

The basis for the medical treatment of prostate cancer is inhibition of the influence of testosterone on the prostate. Surgical castration is in 1997 still the gold standard; it reduces the testosterone level by 90% and the level of dihydrotestosterone (the active metabolite) by 60%. In the eighties luteinising hormone releasing hormone (LH-RH) analogues were introduced to avoid the psychological burden of castration. After an initial stimulation (the flare-up) testosterone decreases to castrate level within 3 weeks. Recently (non-steroidal) anti-androgens, competitive inhibitors of dihydrotestosterone on receptor level were introduced. There are also drugs which inhibit the conversion of testosterone to dihydrotestosterone: 5 alpha-reductase inhibitors. Non-steroidal anti-androgens and 5 alpha-reductase inhibitors do not decrease the testosterone level and therefore cause less loss of libido and energy than castration. Combination of (chemical) castration and anti-androgens is called maximum androgen blockade. This treatment has limited additional value in proportion to the increase in side effects and costs. A new form of treatment is intermittent androgen blockade. With this strategy growth of hormone-insensitive cells in the prostate, which is considered the main determinant of the poor prognosis, might be delayed with reduction of side effects and costs. The role of imidazoles is still investigated; the role of cytotoxic drugs is mainly palliative.     

Topical treatment of genital warts in men, an open study of podophyllotoxin cream compared with solution

In benign prostatic hyperplasia (BPH), basic fibroblast growth factor (bFGF) is found to have a regional distribution, with concentrations in the periurethral zone (where the primitive fibrostromal nodule originates) higher than those of the peripheral subcapsular zone. The aim of the present investigation was to verify whether androgens and epidermal growth factor (EGF) are uniformly distributed from the periurethral to the peripheral zone or whether they show regional differences. Tissue samples, removed by transvesical resection from nine untreated BPH patients, sectioned in periurethral, subcapsular, and intermediate zones, were examined. In the periurethral zone, dihydrotestosterone (DHT), testosterone, and EGF, determined by radioimmunoassay (RIA) techniques after purification on Celite microcolumns and Sep-pak C18 cartridge, showed values significantly higher (mean +/- SD: 1121 +/- 482 pg, 250 +/- 129 pg, and 6.89 +/- 3.28 ng/mg DNA, respectively; P < 0.01) than those of the subcapsular zone (489 +/- 190 pg, 114 +/- 70 pg, and 3.40 +/- 1.90 ng/mg DNA, respectively). A positive linear correlation between EGF, testosterone, and DHT was also observed. The regional distribution of EGF, testosterone, and DHT was similar to that found for bFGF: the highest levels of these factors in the periurethral region allow us to hypothesize on their possible involvement in the rewakening of mesenchymal tissue, leading to the formation of the primitive fibrostromal nodule and then to BPH development.     

Lovastatin-induced apoptosis in prostate stromal cells

Benign prostatic hyperplasia (BPH) is a common disease of aging men. Current medical treatment for this condition is only partially effective, therefore many patients must undergo surgery for symptomatic relief. BPH is caused by an increase in prostate epithelial and stromal cells, especially the latter. Since BPH stromal cells have a long life span and are not very responsive to androgen withdrawal, cultured BPH stromal cells were used to explore the feasibility of pharmacologically inducing apoptosis in these cells. We obtained BPH tissue during surgery, and stromal cells were isolated and maintained in culture. After cells achieved confluence, we induced apoptosis with the HMGCoA reductase inhibitor, lovastatin (30 micromol/L). The effects of testosterone (100 micromol/L), dihydrotestosterone (DHT; 100 micromol/L) and finasteride (100 micromol/L) on lovastatin-induced apoptosis were studied on cells grown in media containing charcoal stripped serum. Similarly, we examined the effect of the cholesterol pathway metabolites, mevalonic acid (30 micromol/L), geranyl geraniol (30 micromol/L), farnesol (10 micromol/L), squalene (30 micromol/L) and 7-ketocholesterol (3 micromol/L) on lovastatin-induced apoptosis. We demonstrated apoptosis by DNA laddering in agarose gels, by fluorescence microscopy following acridine orange staining, and by flow cytometry after end-labeling of DNA strand breaks with biotin-16-dUTP using deoxynucleotidyl exotransferase (TdT). Lovastatin at 30 micromol/L, but not at lower concentrations, induced apoptosis in BPH prostate stromal cells. This was seen (by flow cytometry) in 16.6 +/- 7.3% (mean +/- SD) of BPH cells treated with lovastatin at 72 h vs. 2.5 +/- 1.2% of cells treated with ethanol. Lovastatin-induced apoptosis was not increased in stripped serum or by the addition finasteride, and was not inhibited by testosterone or DHT. Only mevalonate and geranyl geraniol, prevented lovastatin-induced apoptosis whereas farnesol, squalene, or 7-ketocholesterol did not. We conclude that lovastatin can induce apoptosis in BPH stromal cells in vitro, and this is not affected by androgen withdrawal or stimulation. It is unlikely that lovastatin, per se, will be an effective treatment for BPH in vivo, but it does provide a means for inducing apoptosis in vitro. Understanding the apoptotic process in BPH stromal cells ultimately may lead to new therapeutic strategies for BPH.     

Comparative rates of androgen production and metabolism in Caucasian and Chinese subjects

Clinically apparent prostate cancer occurs more commonly among Caucasians living in Western countries than in Chinese in the Far East. Prior studies demonstrated diminished facial and body hair and lower levels of plasma 3 alpha-androstanediol glucuronide and androsterone glucuronide in Chinese than in Caucasian men. Based upon these findings, investigators postulated that Chinese men could have diminished 5 alpha-reductase activity with a resultant decrease in prostate tissue dihydrotestosterone levels and clinically apparent prostate cancer. An alternative hypothesis suggests that decreased 3 alpha-androstanediol glucuronide and androsterone glucuronide levels might reflect reduced production of androgenic ketosteroid precursors as a result of genetic or environmental factors. The present study examined 5 alpha-reductase activity, androgenic ketosteroid precursors, and the influence of genetic and environmental/dietary factors in groups of Chinese and Caucasian men. We found no significant differences in the ratios of 5 beta-:5 alpha-reduced urinary steroids (a marker of 5 alpha-reductase activity) between Chinese subjects living in Beijing, China, and Caucasians living in Pennsylvania. To enhance the sensitivity of detection, we used an isotopic kinetic method to directly measure 5 alpha-reductase activity and found no difference in testosterone to dihydrotestosterone conversion ratios between groups. Then, addressing the alternative hypothesis, we found that the Caucasian subjects excreted significantly higher levels of individual and total androgenic ketosteroids than did their Chinese counterparts. To distinguish genetic from environmental/dietary factors as a cause of these differences, we compared Chinese men living in Pennsylvania and a similar group living in Beijing, China. We detected a reduction in testosterone production rates and total plasma testosterone and sex hormone-binding levels, but not in testosterone MCRs in Beijing Chinese as a opposed to those living in Pennsylvania. Comparing Pennsylvania Chinese with their Caucasian counterparts, we detected no significant differences in total testosterone, free and weakly bound testosterone, sex hormone-binding globulin levels, and testosterone production rates. Taken together, these studies suggest that environmental/dietary, but not genetic, factors influence androgen production and explain the differences between Caucasian and Chinese men.     

Regulation of epidermal growth factor receptor by androgens in human endometrial cells in culture

Women with polycystic ovaries (PCO) have a thicker endometrium than women with normal ovaries. This cannot be due to unopposed oestrogen, as it occurs in ovulatory cycles. Androgens may be involved, as these are raised in women with PCO. The effects of steroids are partly mediated by growth factors and their receptors. The aim of this study was to investigate the effect of androgens on epidermal growth factor (EGF) receptor in human endometrium. Endometrium was enzymatically dispersed and glands and stromal cells separated. Cells were incubated in Ham's F10 medium supplemented with 5% charcoal-stripped fetal calf serum and either androgens or vehicle. Specific binding of [125I]-labelled EGF was measured. Testosterone and dihydrotestosterone (DHT) (10 micromol/l) increased EGF receptor concentration (control 100 +/- 9%, testosterone 196 +/- 23% control; control 100 +/- 1%, DHT 244 +/- 6% control) but did not alter receptor affinity. The effect of testosterone was inhibited by the anti-androgen hydroxyflutamide, but not by the antioestrogen ICI182780 nor the aromatase inhibitor 4-hydroxyandrostenedione. EGF receptor levels were increased by androstenediol (control 100 +/- 2%, androstenediol 120 +/- 10% control) but not by androstanediol, dehydroepiandrosterone (DHA), DHA sulphate or androstenedione. Testosterone and DHT increased EGF receptor concentrations in glandular epithelium (control 100 +/- 24%, testosterone 147 +/- 5%, DHT 185 +/- 30% control). These data suggest that androgens may have an effect on the endometrium via an increase in EGF receptor concentrations.     

Dielectric behavior of non-spherical cells in culture

OBJECTIVE: To determine whether histological analysis of six multiple random biopsies of the gland or analysis of only one biopsy provides a good estimate of the different components of the hyperplastic gland compared with the results obtained from tissue specimens (reference values). MATERIALS AND METHODS: The various components of prostate tissue obtained from 30 men undergoing suprapubic adenomectomy were investigated. The histological analysis was performed on multiple tissue specimens reflecting adenoma (reference values) and on one and six biopsies performed at random on the enucleated material of the hyperplastic gland. Immunohisto chemistry using anti-actin as a label of smooth muscle and specific histological staining coupled with computer-assisted quantitative morphometric analysis was used to ascertain the histological composition of the prostate. RESULTS: The mean ( +/- SD) area densities obtained from tissue specimens were 34.1 +/- 5%, 32.4 +/- 6.9%, 17.6 +/- 4.5% and 15.9 +/- 5.5% of smooth muscular and fibrous tissue, and epithelium and glandular lumen, respectively. The mean ratio of stromal to epithelial hyperplasia averaged 4.05 +/- 1.73. Both one and six biopsies gave a good estimate of fibrous tissue and glandular epithelium, but the percentage of smooth muscles was overestimated and the percentage of glandular lumen was underestimated. There was a significant relation between the prostate area densities of glandular epithelium (r = -0.41, P < 0.05), the percentage area density of prostate smooth muscle (r = 0.43, P < 0.05), and the weight of enucleated adenoma. No correlation was found with prostate-specific antigen (PSA). CONCLUSION: It seems feasible to propose medical treatment of benign prostatic hyperplasia (BPH) based on the histological composition of the prostate gland. One biopsy, reflecting in good proportions the nature of the adenoma, would be used to provide insight into the pathogenesis and therapy of BPH.     

Intracellular regulation of 17 beta-hydroxysteroid dehydrogenase type 2 catalytic activity in A431 cells

There is growing evidence that various isoforms of 17 beta-hydroxysteroid dehydrogenase (17-HSD) are regulated at the level of catalysis in intact cells. A number of investigators have proposed that the NAD(P)/NAD(P)H ratio may control the direction of reaction. In a previous study, we obtained evidence that A431 cells, derived from an epidermoid carcinoma of the vulva, are enriched in 17-HSD type 2, a membrane-bound isoform reactive with C18 and C19 17 beta-hydroxysteroids and 17-ketosteroids. The present investigation was undertaken to confirm the presence of 17-HSD type 2 in A431 cells and to assess intracellular regulation of 17-HSD at the level of catalysis by comparing the activity of homogenates and microsomes with that of cell monolayers. Northern blot analysis confirmed the presence of 17-HSD type 2 mRNA. Exposure of cells to epidermal growth factor resulted in an increase in type 2 mRNA and, for microsomes, increases in maximum velocity (Vmax) with no change in Michaelis constant (Km) for testosterone and androstenedione, resulting in equivalent increases in the Vmax/Km ratio consistent with the presence of a single enzyme. Initial velocity data and inhibition patterns were consistent with a highly ordered reaction sequence in vitro in which testosterone and androstenedione bind only to either an enzyme-NAD or an enzyme-NADH complex respectively. Microsomal dehydrogenase activity with testosterone was 2- to 3-fold higher than reductase activity with androstenedione. In contrast, although cell monolayers rapidly converted testosterone to androstenedione, reductase activity with androstenedione or dehydroepiandrosterone (DHEA) was barely detectable. lactate but not glucose, pyruvate or isocitrate stimulated the conversion of androstenedione to testosterone by monolayers, suggesting that cytoplasmic NADH may be the cofactor for 17-HSD type 2 reductase activity with androstenedione. However, exposure to lactate did not result in a significant change in the NAD/NADH ratio of cell monolayers. It appears that within A431 cells 17-HSD type 2 is regulated at the level of catalysis to function almost exclusively as a dehydrogenase. These findings give further support to the concept that 17-HSD type 2 functions in vivo principally as a dehydrogenase and that its role as a reductase in testosterone formation by either the delta 4 or delta 5 pathway is limited.     

MR566A and MR566B, new melanin synthesis inhibitors produced by Trichoderma harzianum. I. Taxonomy, fermentation, isolation and biological activities

Epitestosterone, a C19-steroid with anti-androgenic activity, was determined in the plasma of 234 boys and men from the ages of 6-86 years, and in the prostate tissue of 15 men 55-82 years of age. It was documented that, while in adulthood the concentration of epitestosterone is about ten times lower than the concentration of testosterone, in the pre-pubertal period the level of epitestosterone is similar or even higher than that of testosterone. In the hyperplastic prostate tissue the content of epitestosterone is comparable to that of androstenedione, it is about twice as high as the content of testosterone and approximately half that of the content of dihydrotestosterone. At least in the case of pre-pubertal boys and in the prostatic tissue it is therefore possible to include epitestosterone into consideration as a regulatory factor for the androgen-dependent events.     

Assisted reproductive medicine: current Islamic bioethical rules

Thermo-dependent changes in the secondary structure of the epithelium and stroma of benign prostatic hyperplasia (BPH) were investigated by Fourier transform infrared (FT-IR) microspectroscopy combined with differential scanning calorimetry (DSC). This microscopic FT-IR/DSC system was used to simulate transurethral thermotherapy for BPH in vitro. The results indicate that thermal-induced conversion from an alpha helix to a beta structure was found in the epithelium and stroma of BPH. However, this thermal-induced conversion behavior in the stroma was less sensitive than that in the epithelium during thermal treatment. The different thermal response between the epithelium and stroma of BPH might be due to the different constitutions of the epithelium and stroma of BPH.     

Prostate-specific antigen and its complexes with alpha 1-antichymotrypsin in the plasma of patients with prostatic disease

OBJECTIVE: To improve the specificity and sensitivity of the prostate-specific-antigen (PSA) assay for the distinction between prostate cancer and benign prostate hyperplasia (BPH). METHODS: Two sensitive immunoassays, one that measures free PSA and PSA complexed to alpha 1-antichymotrypsin (alpha 1-ACT) with the same efficiency (PSAag assay) and another that specifically measures the complex between PSA and alpha 1-ACT, have been designed to measure the PSA forms in the plasma of 84 patients with prostate disease and in the seminal plasma from 60 healthy individuals. RESULTS: The proportion of plasma PSA in complex with alpha 1-ACT was significantly higher in the 34 patients with prostate cancer (89 +/- 12%, mean +/- SD; median, 91%) than in the 50 patients with BPH (71 +/- 12%; 73%) and did not correlate with the total amount of PSA. Normal seminal plasma (n = 60) had 2.1 +/- 0.6 mg/ml PSA, 175 +/- 62 microns/ml alpha 1-ACT and 9.6 +/- 3.4 micrograms/ml PSA: alpha 1-ACT complex. CONCLUSION: These results confirm that PSA: alpha 1-ACT may be a good marker for a differential diagnosis of carcinoma of the prostate and BPH.     

Localization and expression of the alpha1A-1, alpha1B and alpha1D-adrenoceptors in hyperplastic and non-hyperplastic human prostate

PURPOSE: To determine the expression and localization of the alpha1A-1, alpha1B and alpha1D-adrenoceptor (AR) subtypes in hyperplastic and non-hyperplastic human prostate tissue. MATERIALS AND METHODS: The expression of the alpha1-AR subtypes was examined at the mRNA level by quantitative solution hybridization, and at the protein level by immunohistochemistry using subtype selective antibodies. RESULTS: While the overall level of alpha1-AR mRNA was not significantly different between hyperplastic and non-hyperplastic tissue, there were significant differences in the ratio of the alpha1-AR subtypes expressed in the two tissue types. The most significant finding from these studies was the reduced expression of the alpha1b-AR mRNA in both glandular and stromal hyperplasia. By immunohistochemistry, the alpha1A-1-AR was detected in the stroma and not in the glandular epithelium. The alpha1B-AR was localized predominantly in the epithelium and was weakly present in the stroma. Lower levels of the alpha1B-AR were detected in the hyperplastic prostatic epithelium. The alpha1D-AR was detected in areas of stroma and was abundantly present in blood vessels. CONCLUSIONS: The alpha1A-1-, alpha1B- and alpha1D-AR subtypes are differentially localized in human prostate, and the expression levels of all three subtypes are altered in BPH. Alterations in a1-AR subtype expression (particularly the alpha1B-AR) in BPH cannot be solely attributed to changes in tissue morphometry resulting from hyperplasia and may be of significance in the pathogenesis of BPH.     

Localization by in situ hybridization of steroid 5alpha-reductase isozyme gene expression in the human prostate and preputial skin

PURPOSE: The synthesis of dihydrotestosterone is catalyzed by steroid 5alpha-reductase isozymes, designated as types 1 and 2. Controversial results have been reported on the identification of the cell types expressing each isozyme in the human prostate and genital skin. The objective of the present study was to clearly identify at the cellular level the cells containing each type of 5alpha-reductase isozyme. MATERIALS AND METHODS: We used for the first time an in situ hybridization technique involving use of [35S]-labeled oligonucleotide probes to determine the cell type expression patterns of the two 5alpha-reductase isozymes in human prostate and preputial skin. RESULTS: In the prostate, hybridization with types 1 and 2 5alpha-reductase antisense probes led to a positive reaction in both epithelial and stromal cells, while the sense probes did not generate any signal. The silver grain counts for both isozymes revealed a higher labeling in the epithelial cells. In fact, the ratio epithelial cells/stroma was around 2 for both 5alpha-reductase types 1 and 2. In the preputial skin, 5alpha-reductase type 1 was found to be highly expressed in all the layers of the epidermis with the exception of the stratum corneum while a lower labeling was observed in some fibroblasts as well as in the secretory cells of sebaceous glands and excretory duct cells of sweat glands. Type 2 5alpha-reductase showed a very similar pattern of distribution. CONCLUSION: It appears that, in two human tissues, the two 5alpha-reductase isozymes mRNAs are expressed by the same cell types. This new observation should help clarify the physiological role of each type of 5alpha-reductase isozyme.     

Antigen retrieval in cryostat tissue sections and cultured cells by treatment with sodium dodecyl sulfate (SDS)

BACKGROUND: Steroid 5 alpha-reductase is essential for the intracellular accumulation of dihydrotestosterone (DHT), which mediates androgen effects on target tissue. METHODS: In the present study, we describe the differential expression and cellular localization of 5 alpha-reductase 1 and 2 isoenzymes in the human prostate, and untreated and hormone-resistant prostatic carcinomas. The secretory epithelium of normal and hyperplastic glands showed strong nuclear 5 alpha-reductase 1 reactivity. Accordingly, the DHT forming 5 alpha-reductase process in secretory luminal cell types may be mediated predominantly by the type 1 isoenzyme. The androgen-independent basal cell layer variably expressed type 1 and 2 isoenzymes in nuclear and cytoplasmatic compartments. This suggests that circulating androgens are involved to control the basal cell layer, which represents the proliferative compartment of the human prostate. RESULTS: When compared with benign prostate tissue, increased 5 alpha-reductase reactivity was detected in prostate cancer, particularly in high-grade tumors and androgen-insensitive states of the disease. In cancerous lesions, the type 1 isoenzyme tended to shift to the cytoplasm, while the nuclear staining remained unchanged or slightly increased. Referring to the type 2 isoenzyme, increased cytoplasmatic and nuclear enzyme activity was detected in malignant cells when compared with adjacent benign prostate tissue. Even endocrine differentiated tumor cells that consistently lacked the nuclear androgen receptor variably expressed 5 alpha-reductase immunoreactivity. CONCLUSIONS: Although the functional significance of the differential subcellular localization of type 1 and 2 isoenzymes is currently unknown, the present data suggest that prostate cancer retains the DHT forming 5 alpha-reductase process in high-grade lesions and recurrent disease. Accordingly, circulating androgens may be still significant in these hormone-refractory malignancies.     

Prognostic significance of tumour markers in endometrial cancer

BACKGROUND: Steroid 5 alpha-reductase is implicated in the pathogenesis of benign prostatic hyperplasia (BPH). We studied the in vitro and in vivo effects of FR146687, a new inhibitor of 5 alpha-reductase. METHODS: Two isozymes of rat and human 5 alpha-reductases were expressed in 293 cells. In vivo effects of drugs were evaluated on rat and dog prostates. Castrated immature rats were injected with testosterone propionate (TP) or 5 alpha-dihydrotestosterone propionate (DHTP) to induce growth of the ventral prostates. Testosterone and 5 alpha-dihydrotestosterone (DHT) contents in rat and dog prostates were measured by gas chromatography-mass spectrophotometry (GC-MS). RESULTS: FR146687 showed noncompetitive inhibition in both isozymes and no inhibitory effects on other steroid oxidoreductases. In mature rats and castrated immature rats treated with TP, FR146687 dose-dependently reduced ventral prostate and seminal vesicle weight at doses above 0.1 mg/kg, while castrated immature rats treated with DHTP were not affected by FR146687. FR146687 showed more potent reduction of rat prostates than finasteride. DHT concentration in the prostates was significantly reduced when FR146687 was administered to rats and beagles. CONCLUSIONS: FR146687 is a dual inhibitor for 5 alpha-reductase isozymes and significantly reduced the growth and DHT content in the prostate.