Induction of atypical prostatic hyperplasia in rats by sympathomimetic stimulation

Effects of Taraxaci Herba (Dandelion) on Testosterone Propionate-Induced Benign Prostatic Hyperplasia in Rats

Benign prostatic hyperplasia (BPH) is the non-malignant enlargement of the prostate, associated with lower urinary tract symptoms (LUTSs). Taraxaci Herba (TH), commonly known as dandelion, has traditionally been utilized in East Asia to treat symptoms related to LUTSs. Based on this traditional use, our study aimed to explore the inhibitory effects of TH on BPH progression using a testosterone propionate-induced rat model. To induce BPH, male Sprague Dawley rats were castrated and injected subcutaneously with testosterone propionate (3 mg/kg/day) for 28 days. Concurrently, TH extract was administered orally at doses of 100 and 300 mg/kg/day throughout the four-week period of testosterone propionate injections. The TH extract significantly reduced both the absolute and relative weights of the prostate, along with histopathological changes in the gland. Moreover, it lowered serum levels of testosterone and dihydrotestosterone and reduced the expression of the androgen receptor in the prostate. Additionally, the TH extract modulated the protein expressions of Bax and Bcl-2, which are key regulators of apoptosis in prostate cells. Collectively, our findings suggest that TH inhibits BPH development partially by modulating androgen signaling and inducing apoptosis within the prostate.

S100A4 modulates cell proliferation, apoptosis and fibrosis in the hyperplastic prostate

Benign prostatic hyperplasia (BPH) is one of the most common diseases in elderly men worldwide that may result in lower urinary tract symptoms (LUTS). At present, the specific pathophysiological mechanism for BPH/LUTS LUTS remains unclear. S100 calcium binding protein A4 (S100A4), a member of the calcium binding protein family, regulates a variety of biological processes including cell proliferation, apoptosis and fibrosis. The aim of the current study was to explore and clarify the possible role of S100A4 in BPH/LUTS. The human prostate stromal cell line (WPMY-1), rat prostate epithelial cells, human prostate tissues and two BPH rat models were employed in this study. The expression and localization of S100A4 were detected by quantitative real time PCR (qRT-PCR), immunofluorescence microscopy, Western blotting and immunohistochemistry analysis. Also, S100A4 knockdown or overexpression cell models were constructed and a BPH rat model was induced with testosterone propionate (T) or phenylephrine (PE). The BPH animals were treated with Niclosamide, a S100A4 transcription inhibitor. Results demonstrated that S100A4 was mainly localized in human prostatic stroma and rat prostatic epithelium, and showed a higher expression in BPH. Knockdown of S100A4 induced cell apoptosis, cell proliferation arrest and a reduction of tissue fibrosis markers. Overexpression of S100A4 reversed the aforementioned changes. We also demonstrated that S100A4 regulated proliferation and apoptosis mainly through the ERK pathway and modulated fibrosis via Wnt/β-catenin signaling. In conclusion, our novel data demonstrate that S100A4 could play a crucial role in BPH development and may be explored as a new therapeutic target of BPH.

YAP1 Recognizes Inflammatory and Mechanical Cues to Exacerbate Benign Prostatic Hyperplasia via Promoting Cell Survival and Fibrosis

Chronic prostatic inflammation promotes cell survival and fibrosis, leading to benign prostatic hyperplasia (BPH) with aggravated urinary symptoms. It is investigated whether yes-associated protein 1 (YAP1), an organ size controller and mechanical transductor, is implicated in inflammation-induced BPH. The correlation between YAP1 expression and fibrosis in human and rat BPH specimens is analyzed. Furthermore, the effects of YAP1 activation on prostatic cell survival and fibrosis, as well as the underlying mechanism, are also studied. As a result, total and nuclear YAP1 expression, along with downstream genes are significantly upregulated in inflammation-associated human and rat specimens. There is a significant positive correlation between YAP1 expression and the severity of fibrosis or clinical performance. YAP1 silencing suppresses cell survival by decreasing cell proliferation and increasing apoptosis, and alleviates fibrosis by reversing epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) deposition in prostatic BPH-1 and WPMY-1 cells. Mechanistically, inflammatory stimulus and rigid matrix stiffness synergistically activate the RhoA/ROCK1 pathway to provoke cytoskeleton remodeling, thereby promoting YAP1 activation to exacerbate BPH development. Overall, inflammation-triggered mechanical stiffness reinforcement activates the RhoA/ROCK1/F-actin/YAP1 axis, thereby promoting prostatic cell survival and fibrosis to accelerate BPH progression.

The neuroscience of cancer

The nervous system regulates tissue stem and precursor populations throughout life. Parallel to roles in development, the nervous system is emerging as a critical regulator of cancer, from oncogenesis to malignant growth and metastatic spread. Various preclinical models in a range of malignancies have demonstrated that nervous system activity can control cancer initiation and powerfully influence cancer progression and metastasis. Just as the nervous system can regulate cancer progression, cancer also remodels and hijacks nervous system structure and function. Interactions between the nervous system and cancer occur both in the local tumour microenvironment and systemically. Neurons and glial cells communicate directly with malignant cells in the tumour microenvironment through paracrine factors and, in some cases, through neuron-to-cancer cell synapses. Additionally, indirect interactions occur at a distance through circulating signals and through influences on immune cell trafficking and function. Such cross-talk among the nervous system, immune system and cancer-both systemically and in the local tumour microenvironment-regulates pro-tumour inflammation and anti-cancer immunity. Elucidating the neuroscience of cancer, which calls for interdisciplinary collaboration among the fields of neuroscience, developmental biology, immunology and cancer biology, may advance effective therapies for many of the most difficult to treat malignancies.

Inhibition of Human Prostate and Bladder Smooth Muscle Contraction, Vasoconstriction of Porcine Renal and Coronary Arteries, and Growth-Related Functions of Prostate Stromal Cells by Presumed Small Molecule Gαq/11 Inhibitor, YM-254890

Introduction: Lower urinary tract symptoms (LUTS) involve benign prostatic hyperplasia (BPH) and overactive bladder (OAB). Standard-of-care medical treatment includes α1-blockers and antimuscarinics for reduction of prostate and detrusor smooth muscle tone, respectively, and 5α-reductase inhibitors (5-ARI) to prevent prostate growth. Current medications are marked by high discontinuation rates due to unfavourable balance between efficacy and treatment-limiting side effects, ranging from dry mouth for antimuscarinics to cardiovascular dysregulation and a tendency to fall for α1-blockers, which results from hypotension, due to vasorelaxation. Agonist-induced smooth muscle contractions are caused by activation of receptor-coupled G-proteins. However, little is known about receptor- and organ-specific differences in coupling to G-proteins. With YM-254890, a small molecule inhibitor with presumed specificity for Gαq/11 became recently available. Here, we investigated effects of YM-254890 on prostate, bladder and vascular smooth muscle contraction, and on growth-related functions in prostate stromal cells.

Methods: Contractions of human prostate and detrusor tissues, porcine renal and coronary arteries were induced in an organ bath. Proliferation (EdU assay), growth (colony formation), apoptosis and cell death (flow cytometry), viability (CCK-8) and actin organization (phalloidin staining) were studied in cultured human prostate stromal cells (WPMY-1).

Results: Contractions by α1-adrenergic agonists, U46619, endothelin-1, and neurogenic contractions were nearly completely inhibited by YM-254890 (30 nM) in prostate tissues. Contractions by cholinergic agonists, U46619, endothelin-1, and neurogenic contractions were only partly inhibited in detrusor tissues. Contractions by α1-adrenergic agonists, U46619, endothelin-1, and neurogenic contractions were strongly, but not fully inhibited in renal arteries. Contractions by cholinergic agonists were completely, but by U46619 and endothelin-1 only strongly inhibited, and neurogenic contractions reduced by half in coronary arteries. YM-254890 had no effect on agonist-independent contractions induced by highmolar (80 mM) potassium chloride (KCl). Neurogenic detrusor contractions were fully sensitive to tetrodotoxin. In WPMY-1 cells, YM-254890 caused breakdown of actin polymerization and organization, and obvious, but clearly limited decreases of proliferation rate, colony formation and viability, and slightly increased apoptosis.

Conclusion: Intracellular post-receptor signaling pathways are shared by Gαq-coupled contractile receptors in multiple smooth muscle-rich organs, but to different extent. While inhibition of Gαq/11 causes actin breakdown, anti-proliferative effects were detectable but clearly limited. Together this may aid in developing future pharmaceutical targets for LUTS and antihypertensive medication.

Concentration-dependent alpha1-Adrenoceptor Antagonism and Inhibition of Neurogenic Smooth Muscle Contraction by Mirabegron in the Human Prostate

Introduction: Mirabegron is available for treatment of storage symptoms in overactive bladder, which may be improved by β₃-adrenoceptor-induced bladder smooth muscle relaxation. In addition to storage symptoms, lower urinary tract symptoms in men include obstructive symptoms attributed to benign prostatic hyperplasia, caused by increased prostate smooth muscle tone and prostate enlargement. In contrast to the bladder and storage symptoms, effects of mirabegron on prostate smooth muscle contraction and obstructive symptoms are poorly understood. Evidence from non-human smooth muscle suggested antagonism of α₁-adrenoceptors as an important off-target effect of mirabegron. As α₁-adrenergic contraction is crucial in pathophysiology and medical treatment of obstructive symptoms, we here examined effects of mirabegron on contractions of human prostate tissues and on proliferation of prostate stromal cells.

Methods: Contractions were induced in an organ bath. Effects of mirabegron on proliferation, viability, and cAMP levels in cultured stromal cells were examined by EdU assays, CCK-8 assays and enzyme-linked immunosorbent assay.

Results: Mirabegron in concentrations of 5 and 10 μM, but not 1 µM inhibited electric field stimulation-induced contractions of human prostate tissues. Mirabegron in concentrations of 5 and 10 µM shifted concentration response curves for noradrenaline-, methoxamine- and phenylephrine-induced contractions to the right, including recovery of contractions at high concentrations of α₁-adrenergic agonists, increased EC₅₀ values, but unchanged E_max values. Rightshifts of noradrenaline concentration response curves and inhibition of EFS-induced contractions were resistant to L-748,337, l-NAME, and BPIPP. 1 µM mirabegron was without effect on α₁-adrenergic contractions. Endothelin-1- and U46619-induced contractions were not affected or only inhibited to neglectable extent. Effects of mirabegron (0.5–10 µM) on proliferation and viability of stromal cells were neglectable or small, reaching maximum decreases of 8% in proliferation assays and 17% in viability assays. Mirabegron did not induce detectable increases of cAMP levels in cultured stromal cells.

Conclusion: Mirabegron inhibits neurogenic and α₁-adrenergic human prostate smooth muscle contractions. This inhibition may be based on antagonism of α₁-adrenoceptors by mirabegron, and does not include activation of β₃-adrenoceptors and requires concentrations ranging 50-100fold higher than plasma concentrations reported from normal dosing. Non-adrenergic contractions and proliferation of prostate stromal cells are not inhibited by mirabegron.

Animal models of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) and associated lower urinary tract symptoms are common clinical concerns that affect aging men all over the world. The underlying molecular and cellular mechanisms remain elusive. Over the past few years, a number of animal models of BPH, including spontaneous model, BPH-induction model, xenograft model, metabolic syndrome model, mechanical obstruction model, and transgenic model, have been established that may provide useful tools to fill these critical knowledge gaps. In this review, we therefore outlined the present status quo for animal models of BPH, comparing the pros and cons with respect to their ability to mimic the etiological, histological, and clinical hallmarks of BPH and discussed their applicability for future research.

Quantification of neural and hormonal receptors at the prostate of long-term sexual behaving male rats after lesion of pelvic and hypogastric nerves

Prostate function is regulated by androgens and a neural control via the pelvic and hypogastric nerves. As such, this sexual gland contains receptors for acetylcholine and noradrenaline, although it is unknown whether the expression of these receptors is affected by sexual behavior and even less by denervation of the gland. Thus, the purpose of this work was to evaluate the effect of repeated sexual behavior on the expression of noradrenaline, acetylcholine, and androgen receptors at the prostate, and how they are affected by denervation. To achieve this, we used sexually experienced males denervated at the pelvic or hypogastric nerves, or both. The messenger (mRNA) and protein for androgen, noradrenergic, and cholinergic receptors were evaluated. The weight of the gland and the levels of serum testosterone were also measured. We found that: (1) sexual behavior was not affected by denervation; (2) blood testosterone levels increased due to sexual behavior but such increase is prevented by denervation; (3) the weight of the ventral prostate increased with sexual behavior but was not affected by denervation; (4) AR messenger levels increased with sexual behavior but were not altered by denervation; (5) the messenger for noradrenergic and cholinergic receptors decreased after denervation, and those for muscarinic receptors increased, and (6) only AR protein decreased after denervation of both nerves, while those for other receptors remained unchanged. In summary, we show that the three receptors have different regulatory mechanisms, and that only androgen receptors are regulated by both autonomic systems.

The protective effect of Sophora japonica on prostatic hypertrophy and inflammation in rat

The atypical adenomatous hyperplasia (AAH) is invariably an incidental histological change, with no clinical findings specific for its diagnosis, and the mean patient age at diagnosis is 64-70 years. The incidence of AAH varies between 1.5 and 19.6% of transurethral resections and in up to 33% of radical prostatectomies. Herbal medicines are becoming a popular option in the treatment of prostatic-related diseases, such as date palm pollen and saw palmetto in the treatment of prostatic hyperplasia. A testosterone/citral-induced AAH in Wistar rat model was used to evaluate the protective effect of Sophora japonica fruit extract (SFE). The present study suggests that SFE has an ameliorating effect on the prostatic hypertrophy and inflammation through its effect on clusterin, IGF, IL-6, IL-8, TNF-α, and TGF-β1 expression. In addition, the administration of SFE ameliorated the inflammatory score, and histopathological changes in AAH-induced rats in a dose-dependent manner. The treatment with SFE reduced the number of prostatic acini in AAH rat model and decreased the production of pro-inflammatory cytokines. The fruit extract of S. japonica was characterized by determination total phenol content (60.3 mg of gallic acid equivalent/g of dry extract), total flavonoid content (97.9 mg quercetin equivalent/g of dry extract) and the major isoflavonoid sophoricoside (302.9 ± 2.6 µg/g of the extract). In conclusion, SFE has an ameliorating effect on the prostatic hypertrophy and inflammation. This effect may be attributed to the ability of SFE to decrease the production of pro-inflammatory cytokines, TNF-α, IL-1β and IGF-1 as well as an increase in TGF-β1.

The Neural Regulation of Cancer

The nervous system is intimately involved in physiological processes from development and growth to tissue homeostasis and repair throughout the body. It logically follows that the nervous system has the potential to play analogous roles in the context of cancer. Progress toward understanding the crucial role of the nervous system in cancer has accelerated in recent years, but much remains to be learned. Here, we highlight rapidly evolving concepts in this burgeoning research space and consider next steps toward understanding and therapeutically targeting the neural regulation of cancer.

Neuronal Activity in Ontogeny and Oncology

The nervous system plays a central role in regulating the stem cell niche in many organs, and thereby pivotally modulates development, homeostasis, and plasticity. A similarly powerful role for neural regulation of the cancer microenvironment is emerging. Neurons promote the growth of cancers of the brain, skin, prostate, pancreas, and stomach. Parallel mechanisms shared in development and cancer suggest that neural modulation of the tumor microenvironment may prove a universal theme, although the mechanistic details of such modulation remain to be discovered for many malignancies. We review here what is known about the influences of active neurons on stem cell and cancer microenvironments across a broad range of tissues, and we discuss emerging principles of neural regulation of development and cancer.

D-004 ameliorates phenylephrine-induced urodynamic changes and increased prostate and bladder oxidative stress in rats

BACKGROUND

Lower urinary tract symptoms (LUTS) in patients with benign prostatic hyperplasia (BPH) mainly depend on alpha1-adrenoreceptors (α1-ADR) stimulation, but a link with oxidative stress (OS) is also involved. D-004, a lipid extract of Roystonea regia fruits, antagonizes ADR-induced responses and produces antioxidant effects. The objective of this study was to investigate whether D-004 produce antioxidant effects in rats with phenylephrine (PHE)-induced urodynamic changes.

METHODS

Rats were randomized into eight groups (ten rats/group): a negative vehicle control and seven groups injected with PHE: a positive control, three treated with D-004 (200, 400 and 800 mg/kg) and three others with tamsulosin (0.4 mg/kg), grape seed extract (GSE) (250 mg/kg) and vitamin E (VE) (250 mg/kg), respectively.

RESULTS

Effects on urinary total volume (UTV), volume voided per micturition (VM), malondialdehyde (MDA) and carbonyl groups (CG) concentrations in prostate and bladder homogenates were study outcomes. While VM and UTV lowered significantly in the positive control as compared to the negative control group, the opposite occurred with prostate and bladder MDA and CG values. D-004 (200-800 mg/kg) increased significantly both VM and UTV, lowered significantly MDA in prostate and bladder homogenates, and reduced GC levels only in the prostate. Tamsulosin increased significantly VM and UTV, but unchanged oxidative variables. GSE and VE unchanged the UTV, whereas VE, not GSE, modestly but significantly attenuated the PHE-induced decrease of VM.

CONCLUSIONS

Single oral administration of D-004 (200-800 mg/kg) was the only treatment that ameliorated the urodynamic changes and reduced increased oxidative variables in the prostate of rats with PHE-induced prostate hyperplasia.

Immunomodulatory effect of red onion (Allium cepa Linn) scale extract on experimentally induced atypical prostatic hyperplasia in Wistar rats

Red onion scales (ROS) contain large amounts of flavonoids that are responsible for the reported antioxidant activity, immune enhancement, and anticancer property. Atypical prostatic hyperplasia (APH) was induced in adult castrated Wistar rats by both s.c. injection of testosterone (0.5 mg/rat/day) and by smearing citral on shaved skin once every 3 days for 30 days. Saw palmetto (100 mg/kg) as a positive control and ROS suspension at doses of 75, 150, and 300 mg/kg/day were given orally every day for 30 days. All medications were started 7 days after castration and along with testosterone and citral. The HPLC profile of ROS methanolic extract displayed two major peaks identified as quercetin and quercetin-4′-β-O-D-glucoside. Histopathological examination of APH-induced prostatic rats revealed evidence of hyperplasia and inflammation with cellular proliferation and reduced apoptosis Immunohistochemistry showed increased tissue expressions of IL-6, IL-8, TNF-α, IGF-1, and clusterin, while TGF-β1 was decreased, which correlates with the presence of inflammation. Both saw palmetto and RO scale treatment have ameliorated these changes. These ameliorative effects were more evident in RO scale groups and were dose dependent. In conclusion, methanolic extract of ROS showed a protective effect against APH induced rats that may be attributed to potential anti-inflammatory and immunomodulatory effects.

Age-related changes in the innervation of the prostate gland: implications for prostate cancer initiation and progression

The adult prostate gland grows and develops under hormonal control while its physiological functions are controlled by the autonomic nervous system. The prostate gland receives sympathetic input via the hypogastric nerve and parasympathetic input via the pelvic nerve. In addition, the hypogastric and pelvic nerves also provide sensory inputs to the gland. This review provides a summary of the innervation of the adult prostate gland and describes the changes which occur with age and disease. Growth and development of the prostate gland is age dependent as is the occurrence of both benign prostate disease and prostate cancer. In parallel, the activity and influence of both the sympathetic and parasympathetic nervous system changes with age. The influence of the sympathetic nervous system on benign prostatic hyperplasia is well documented and this review considers the possibility of a link between changes in autonomic innervation and prostate cancer progression.

Silodosin inhibits noradrenaline-activated transcription factors Elk1 and SRF in human prostate smooth muscle

Background

The transcription factors Elk1 and serum response factor (SRF) are central regulators of cell cycle and phenotype in various cell types. Elk1 is activated by phosphorylation (serine-383), while activation of SRF requires its co-factor, myocardin. Activation of Elk1 and SRF results in binding to specific DNA sequences in promoter regions, and may be induced by adrenergic receptor activation in different organs.

Objective

To examine the effects of adrenergic stimulation on Elk1 and SRF in the human prostate and the ability of the highly selective α1A-adrenoceptor antagonist, silodosin, on transcription factor activation.

Methods

Prostate tissue was obtained from patients undergoing radical prostatectomy. Expression of Elk1, SRF, and myocardin was estimated by Western blot and immunohistochemistry. Colocalizations were studied by double immunofluorescence staining. Noradrenaline- (NA-) and phenylephrine- (PE-) induced phosphorylation of Elk1 was assessed by Western blot analysis using a phospho-specific antibody. NA-induced activation of Elk1 and SRF was investigated by electrophoretic mobility shift assay (EMSA).

Results

Immunoreactivity for Elk1, SRF, and myocardin was observed in stromal cells of tissues from each patient. In fluorescence stainings, SRF colocalized with myocardin and α-smooth muscle actin (αSMA). Stimulation of prostate tissues with PE (10 µM) or NA (30 µM) increased the phosphorylation of Elk1 at serine-383. NA-induced Elk1 activation was confirmed by EMSA, where a NA-induced binding of Elk1 to the DNA sequence TTTGCAAAATGCAGGAATTGTTTTCACAGT was observed. Similarly, NA caused SRF binding to the SRF-specific DNA sequence CCATATTAGGCCATATTAGG. Application of silodosin (3 µM) to prostate tissues reduced the activity of Elk1 and SRF in NA-stimulated tissues.

Conclusions

Silodosin blocks the activation of the two transcription factors, Elk1 and SRF, which is induced by noradrenaline in the human prostate. A role of α1-adrenoceptors beyond smooth muscle contraction may be considered, which includes a function in transcriptional regulation.

Inhibition of adrenergic human prostate smooth muscle contraction by the inhibitors of c-Jun N-terminal kinase, SP600125 and BI-78D3

BACKGROUND AND PURPOSE α(1) -Adrenoceptor-induced contraction of prostate smooth muscle is mediated by calcium- and Rho kinase-dependent mechanisms. In addition, other mechanisms, such as activation of c-jun N-terminal kinase (JNK) may be involved. Here, we investigated whether JNK participates in α(1)-adrenoceptor-induced contraction of human prostate smooth muscle. EXPERIMENTAL APPROACH Prostate tissue was obtained from patients undergoing radical prostatectomy. Effects of the JNK inhibitors SP600125 (50 µM) and BI-78D3 (30 µM) on contractions induced by phenylephrine, noradrenaline and electric field stimulation (EFS) were studied in myographic measurements. JNK activation by noradrenaline (30 µM) and phenylephrine (10 µM), and the effects of JNK inhibitors of c-Jun phosphorylation were assessed by Western blot analyses with phospho-specific antibodies. Expression of JNK was studied by immunohistochemistry and fluorescence double staining. KEY RESULTS The JNK inhibitors SP600125 and BI-78D3 reduced phenylephrine- and noradrenaline-induced contractions of human prostate strips. In addition, SP600125 reduced EFS-induced contraction of prostate strips. Stimulation of prostate tissue with noradrenaline or phenylephrine in vitro resulted in activation of JNK. Incubation of prostate tissue with SP600125 or BI-78D3 reduced the phosphorylation state of c-Jun. Immunohistochemical staining demonstrated the expression of JNK in smooth muscle cells of human prostate tissue. Fluorescence staining showed that α(1A)-adrenoceptors and JNK are expressed in the same cells. CONCLUSIONS AND IMPLICATIONS Activation of JNK is involved in α(1)-adrenoceptor-induced prostate smooth muscle contraction. Models of α(1)-adrenoceptor-mediated prostate smooth muscle contraction should include this JNK-dependent mechanism.

Fibrosis-related gene expression in the prostate is modulated by doxazosin treatment

AIMS

To gain new insights into the molecular mechanisms of action of doxazosin, we investigated the prostatic stroma ultrastructure and the expression of genes involved with fibrosis, such as collagen type I and III (COL1A1 and COL3A1, respectively) and TGF-beta 1, in the rat ventral prostate.

MAIN METHODS

Adult Wistar rats were treated with doxazosin (25mg/kg/day), and the ventral prostates were excised at 7 and 30days after treatment. Untreated rats were controls. Ventral prostates were subjected to ultrastructural, immunohistochemical, biochemical and molecular analyses.

KEY FINDINGS

Doxazosin-treated prostates showed thickened bundles of collagen fibrils, activated fibroblasts, enlarged neurotransmitter vesicles and increased tissue immunostaining for collagen type I and type III when compared to untreated prostates. After 7 and 30days of doxazosin treatment mRNA expression of COL1A1 and COL3A1 was significantly increased and reduced, respectively, compared to the control group. TGF-beta 1 mRNA and protein levels were increased after 7days of doxazosin treatment, whereas only mRNA levels remained increased after 30days of treatment.

SIGNIFICANCE

Our data suggest that relaxation of smooth muscle cells by alpha-blockers interferes with the mechanical dynamics of the prostatic stroma extracellular matrix components, generating a pro-fibrotic effect probably via the TGF-beta 1 signaling pathway. Long term treatment with doxazosin may also lead to a reduced turnover of extracellular matrix components. Our results add to a better understanding of the molecular mechanisms behind the effects of alpha-blockade on prostatic histoarchitecture and the response to treatment for benign prostatic hyperplasia.

Anti-inflammatory and antiproliferative activities of date palm pollen (Phoenix dactylifera) on experimentally-induced atypical prostatic hyperplasia in rats

BACKGROUND

Atypical prostatic hyperplasia (APH) is a pseudoneoplastic lesion that can mimic prostate adenocarcinoma because of its cytologic and architectural features. Suspension of date palm pollen (DPP) is an herbal mixture that is widely used in folk medicine for male infertility. The aim of the present study was to evaluate the effect of DPP suspension and extract on APH-induced rats.

METHODS

APH was induced in adult castrated Wistar rats by both s.c. injection of testosterone (0.5 mg/rat/day) and smearing citral on shaved skin once every 3 days for 30 days. Saw palmetto (100mg/kg), DPP suspension (250, 500 and 1000 mg/kg), and lyophilized DPP extract (150,300 and 600 mg/kg) were given orally daily for 30 days. All medications were started 7 days after castration and along with testosterone and citral.

RESULTS

The histopathological feature in APH-induced prostate rats showed evidence of hyperplasia and inflammation. Immunohistochemical examination revealed that the expressions of IL-6, IL-8, TNF-α, IGF-1 and clusterin were increased, while the expression of TGF-β1 was decreased that correlates with presence of inflammation. Moreover, histopathological examination revealed increased cellular proliferation and reduced apoptosis in ventral prostate. Both saw palmetto and DPP treatment has ameliorated these histopathological and immunohistochemical changes in APH-induced rats. These improvements were not associated with reduction in the prostatic weight that may be attributed to the persistence of edema.

CONCLUSION

DPP may have a potential protective effect in APH-induced Wistar rats through modulation of cytokine expression and/or upregulation of their autocrine/paracrine receptors.

Etiopathogenesis of benign prostatic hypeprlasia

Benign prostatic hyperplasia (BPH) is the most common condition affecting men older than 50 years of age. It affects about 10 percent of men under the age of 40, and increases to about 80 percent by 80 years of age. BPH is a hyperplastic process of the fibromuscular stromal and glandular epithelial elements of the prostate. Aging and the presence of the functional testes are the two established risk factors for the development of BPH. The etiopathogenesis of BPH is still largely unresolved, but multiple partially overlapping and complementary theories have been proposed, all of which seem to be operative at least to some extent. This review is focused on recent progress in this area and on the growing consensus for the important mechanisms underlying the etiology and pathogenesis of BPH.

A signaling network in phenylephrine-induced benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is an age-related disease of unknown etiology characterized by prostatic enlargement and coinciding with distinctive alterations in tissue histomorphology. To identify the molecular mechanisms underlying the development of BPH, we conducted a DNA microarray study using a previously described animal model in which chronic alpha(1)-adrenergic stimulation by repeated administration of phenylephrine evokes histomorphological changes in the rat prostate that resemble human BPH. Bioinformatic tools were applied to microarray data obtained from prostate tissue to construct a network model of potentially relevant signal transduction pathways. Significant involvement of inflammatory pathways was demonstrable, including evidence for activation of a TGF-beta signaling cascade. The heterodimeric protein clusterin (apolipoprotein J) was also identified as a prominent node in the network. Responsiveness of TGF-beta signaling and clusterin gene and protein expression were confirmed independently of the microarray data, verifying some components of the model. This is the first attempt to develop a comprehensive molecular network for histological BPH induced by adrenergic activation. The study also implicated clusterin as a novel biochemical target for therapy.

Inhibition of monoamine oxidase A promotes secretory differentiation in basal prostatic epithelial cells

Monoamine oxidase A (MAO-A) expression is associated with high-grade prostate cancer. Immunohistochemistry showed that MAO-A is also expressed in the basal epithelial cells of normal prostate glands. Using cultured primary prostatic epithelial cells as a model, we showed that MAO-A prevents basal epithelial cells from differentiating into secretory cells. Under differentiation-promoting conditions, clorgyline, an irreversible MAO-A inhibitor, induced secretory cell-like morphology and repressed expression of cytokeratin 14, a basal cell marker. More importantly, clorgyline induced mRNA and protein expression of androgen receptor (AR), a hallmark of secretory epithelial cells. In clorgyline-treated cells, androgen induced luciferase activity controlled by the promoter of prostate-specific antigen, an AR target gene, in a dose-dependent manner. This activity was blocked by the AR antagonist Casodex, showing that AR is functional. In turn, androgen decreased MAO-A expression in clorgyline-treated, secretory-like cells. Our results demonstrated that cultured basal epithelial cells have the potential to differentiate into secretory cells, and that inhibition of MAO-A is a key factor in promoting this process. Increased expression of MAO-A in high-grade prostate cancer may be an important contributor to its de-differentiated phenotype, raising the possibility that MAO-A inhibition may restore differentiation and reverse the aggressive behavior of high-grade cancer.

Effect of Prolactin and Bromocriptine on the Population of Prostate Neuroendocrine Cells from Intact and Cyproterone Acetate-Treated Rats: Stereological and Immunohistochemical Study

This work deals with the quantification of serotonin-immunoreactive prostate neuroendocrine cells (NECs) in rats exposed to prolactin in normal, cyproterone acetate-exposed, and bromocriptine-exposed animals to establish the possible influence of prolactin with or without androgenic blockade on this cell population. Thirty male peripubertal Sprague-Dawley rats were grouped as controls (CT) and those treated with cyproterone acetate (CA), cyproterone acetate plus prolactin, cyproterone acetate plus bromocriptine, prolactin (PL), and bromocriptine (BC). The volume of ductal epithelium (Vep) and total number (NSER) of the NECs serotonin-immunoreactive were measured. NECs were detected in the periurethral ducts. Compared to CT, Vep was increased in PL and BC and NSER was decreased in CA and increased in the prolactin or bromocriptine groups. The androgenic blockade decreases NSER in rat prostate; PL induces in normal and cyproterone acetate-treated rats the increase of NSER; and BC exerts a local effect over the prostate similar to that described for PL.

The altered homeostatic theory: A hypothesis proposed to be useful in understanding and preventing ischemic heart disease, hypertension, and diabetes – including reducing the risk of age and atherosclerosis

Evidence will be presented to support the usefulness of the altered homeostatic theory in understanding basic pathogenetic mechanisms of ischemic heart disease (IHD), hypertension, and diabetes, and in improving prevention of these disorders. The theory argues that: IHD, hypertension, and diabetes share the same basic pathogenesis; risk factors favor a sympathetic homeostatic shift; preventative factors favor a parasympathetic homeostatic shift; risk and preventative factors oppose each other through a dynamic risk/prevention balance; and prevention should be based on improving the risk/prevention balance. Prevention based on improving the risk/prevention balance should be more effective, as this method is regarded as reflecting more accurately basic pathogenetic mechanisms. As example, the theory argues that the risk of supposedly nonmodifiable risk factors as age and the risk of relatively nonmodifiable atherosclerosis can be reduced significantly. The possible validity of the altered homeostatic theory was tested by a study based on multiple associations. Findings support a common pathogenesis for IHD, hypertension, and diabetes based on a sympathetic homeostatic shift, and the usefulness of prevention based on improving the risk/prevention balance by using standard pharmaceutical and lifestyle preventative measures. The same set of multiple and diverse risk factors favored IHD, hypertension, and diabetes, and the same set of multiple and diverse pharmaceutical and lifestyle preventative measures prevented these disorders. Also, the same set of preventative agents generally improved cognitive function and bone density, and reduced the incidence of Alzheimer's disease, atrial fibrillation, and cancer. Unexpectedly, evidence was developed that four major attributes of sympathetic activation represent four major risk factors; attributes of sympathetic activation are a tendency toward thrombosis and vasoconstriction, lipidemia, inflammation, and hyperglycemia, and corresponding risk factors are endothelial dysfunction (which expresses thrombosis/vasoconstriction and epitomizes this tendency), dyslipidemia, inflammation, and insulin resistance. These findings, plus other information, provide evidence that dyslipidemia acts mainly as a marker of risk of IHD, rather than being the basic mechanism of this disorder. However, prevention generally is based solely on improvement of dyslipidemia; basing prevention on dyslipidemia relatively underemphasizes the importance of other significant risk factors and, by certifying its validity, discourages alternate pathogenetic approaches. Also, development of myocardial infarction is approached differently. It seems generally accepted that dyslipidemia results rather automatically in infarction through the sequence of atherosclerosis, atherosclerotic complications, and thrombosis. In contrast, distinction is made between development of atherosclerosis and acute induction of infarction--where atherosclerosis is only one of multiple risk factors.

Effect of D-004, a Lipid Extract from the Cuban Royal Palm Fruit, on Atypical Prostate Hyperplasia Induced by Phenylephrine in Rats

BACKGROUND AND OBJECTIVE

Benign prostatic hyperplasia (BPH) is a non-malignant enlargement of the prostate that results in obstructive lower urinary tract symptoms. Saw palmetto (Serenoa repens), the dwarf American palm (Arecaceae family), is commonly used to treat BPH. The Cuban royal palm (Roystonea regia) also belongs to the Arecaceae family, and 200-400mg of D-004, a lipid extract from its fruits, administered orally for 14 days has been shown to prevent testosterone- but not dihydrotestosterone-induced prostatic hyperplasia in rats. D-004 (125-250 microg/mL) added to preparations of rat vas deferens caused a marked, dose-dependent and significant inhibition of noradrenaline-induced smooth muscle contraction, a response mediated through alpha(1)-adrenoceptors, and was more effective in these respects than Saw palmetto. However, the in vivo effects of D-004 and Saw palmetto on the hypertensive response induced by noradrenaline were modest (albeit significant), and neither treatment affected resting blood pressure or heart rate in rats. The differential effects of D-004 in in vitro and in vivo models could be related to a differential affinity for adrenoceptor subtypes or to different bioavailabilities in vascular and urogenital targets. Phenylephrine injected into rodents induces prostatic hyperplasia with all the characteristic morphological changes of the condition but does not result in enlargement of the prostate. Therefore, this phenylephrine-induced change in rat prostate tissue is called atypical prostatic hyperplasia. It serves as an in vivo model of prostatic hyperplasia induced by stimulation of alpha(1)-adrenoceptors. The objective of this study was to determine whether D-004 can inhibit induction of atypical prostatic hyperplasia by phenylephrine in rats.

METHODS

Rats were randomly distributed into five groups (ten rats/group). One group was a negative control and received oral vehicle only. The other four groups were injected subcutaneously with phenylephrine (2 mg/kg): of these groups, one was a positive control receiving the vehicle, and the other three groups were treated with D-004 or Saw palmetto (both 400 mg/kg) or tamsulosin 0.4 mg/kg. All active treatments were given orally for 28 days. After completion of treatment, rats were placed unrestrained in metabolic cages and micturition studies were performed. The rats were later killed and their prostates removed and weighed. Prostate samples were processed for histological study, with histological changes being assessed according to a scoring system. Bodyweight was measured at baseline and at weekly intervals.

RESULTS

Histological examination of positive control rats revealed features of atypical prostatic hyperplasia, with piling-up, papillary and cribiform patterns and budding-out of epithelial cells. Micturition assessment revealed that phenylephrine significantly lowered both the total volume of urine in 1 hour and the volume per micturition; the latter was considered the main efficacy variable. D-004 and Saw palmetto extracts significantly prevented this reduction in volume per micturition by 70.5% and 68.6%, respectively, while tamsulosin totally abolished the reduction in micturition induced by phenylephrine (100% inhibition). Tamsulosin, D-004 and Saw palmetto significantly reduced the histological changes of atypical prostatic hyperplasia induced by phenylephrine by 73.1%, 61.2% and 50.0%, respectively.

CONCLUSIONS

Administration of D-004 resulted in marked and significant prevention of phenylephrine-induced impairment of micturition and histological changes in rat prostate. These findings indicate that, in vivo, D-004 effectively opposes these responses to phenylephrine, which are mediated through urogenital alpha(1)-adrenoceptors. In this respect, D-004 was moderately more effective than Saw palmetto, a phytotherapeutic standard used to treat BPH, but less effective than tamsulosin, a selective alpha(1A)-adrenoceptor antagonist.

Differentiated rabbit prostatic stromal cells in primary culture display functional α1A-adrenoceptors

AIMS

BPH is characterized by uncontrolled proliferation and increased contractility of prostatic smooth muscle cells. The activation of alpha1-adrenoceptors (alpha1-AR) seems involved in the latter event, but the lack of in vitro models expressing these receptors has hampered a more specific characterization of their role. In order to do so, we attempted to develop a new model of rabbit cultured prostatic stromal cells (PSC) in a non-proliferative and differentiated state.

METHODS

The expression of cytoskeletal and stromal markers was confirmed by immunohistochemistry on primary cultured PSC. Alpha1-AR subtype expression was assessed by RT-PCR, while receptor coupling to the ERK1/ERK2 and calcium pathways was studied by Western Blot and Fura-2 calcium imaging, respectively.

RESULTS

Cells grown under non-proliferative conditions displayed a differentiated phenotype, with expression of contractile cytoskeletal and stromal proteins. Furthermore, the alpha1A-AR was shown to activate ERK1/ERK2 as well as calcium signaling.

CONCLUSION

These results emphasize the interest of this model for the characterization of PSC adrenergic regulation, in particular through the little-known alpha1A-AR.

Quantitative and immunohistochemical evaluation of PCNA, androgen receptors, apoptosis, and Glutathione-S-Transferase P1 on preneoplastic changes induced by cadmium and zinc chloride in the rat ventral prostate

BACKGROUND

This study was directed to evaluate the immunoexpression of markers for cell proliferation, apoptosis, nuclear androgen receptors, and Glutathione-S-Transferase P1 (GSTP1), in preneoplastic changes induced by cadmium chloride (Cd) and cadmium plus zinc chloride (Cd + Zn) in rat prostate.

METHODS

The following parameters were calculated in ventral prostate of normal rats and rats that received Cd or Cd + Zn in drinking water during 24 months: numerical densities of columnar, basal, and GSTP1 immunoreactive epithelial cells; percentages of cells immunoreactive to: PCNA, (LI(PCNA)), androgen receptors (LI(AR)), and of apoptotic cells.

RESULTS

The LI(PCNA) was significantly increased in the animals exposed to Cd + Zn, whereas the numerical densities of both columnar (N(V) columnar cells), and GSTP1 immunoreactive (N(V) GSTP1+) cells were significantly increased in the animals treated with metals in comparison with the controls. No significant differences between the two sources of dysplasias (Cd and Cd + Zn) respecting to LI(PCNA), N(V) columnar cells, and N(V) GSTP1+ were observed. The two types of dysplasias considered together showed a significant increase for the N(V) basal, N(V) columnar, and N(V) GSTP1+ cells in comparison with normal acini of treated and controls. The percentage of apoptotic nuclei did not show significant differences among the three groups studied.

CONCLUSIONS

(1) The zinc has little influence in the development of the dysplastic changes of the rat prostate mediated by cadmium. (2) The decrease of apoptosis has little influence in the development of dysplasia. (3) GSTP1 could play a role in the response to the oxidative stress in the dysplastic changes caused by cadmium.

Effect of neurokinins on canine prostate cell physiology

BACKGROUND

Sensory peptide neurotransmitters have been implicated as significant regulators of prostate growth. This study was designed to evaluate the role of neurokinins in proliferation, differentiation, and contraction of canine prostate cells in culture.

METHODS

NK1, NK2, and NK3 receptor subtypes were localized in canine prostate tissue by immunocytochemistry and ligand binding studies. Functional effects of neurokinin agonists were tested on cell differentiation (expression of smooth muscle actin (SMA)), proliferation (MTS assay), and contraction of canine prostate cells in culture.

RESULTS

Immunocytochemical staining of canine prostate sections revealed strong stromal staining for NK1 together with weak stromal staining for NK2 and even weaker staining for NK3. Furthermore, there was overlapping localization of NK1 receptors, substance P (SP), and calcitonin gene-regulated peptide (CGRP) in prostate tissue sections. SP caused concentration-dependent increase in SMA expression that was attenuated in a concentration-dependent manner by YM-44778, a non-selective antagonist for neurokinin receptors, but not by either the NK2 antagonist (SR-48968) nor by the NK3 antagonist (SB-223412). SP and neurokinin A (NKA) also caused a modest contraction of stromal cells in collagen gels. NKA stimulated proliferation of prostate epithelial cells without any apoptotic effect, which was attenuated by SR-48968. Surprisingly, in binding studies NK3 appeared to be the most abundant neurokinin receptor subtype, although functional studies failed to reveal significant coupling of this receptor.

CONCLUSIONS

Our results suggest that, at least in vitro, neurokinins have modest effects on canine prostate epithelial cell proliferation, stromal differentiation, and contraction.

Phenylephrine-induced neurogenic prostatitis facilitates the promotion of PIN-like lesions in rats

BACKGROUND

Atypical prostate hyperplasia, resembling PIN lesions in men, together with chronic inflammatory exudates, have been reported after chronic administration of phenylephrine (PE). The present study aims to characterize the evolution of the expression of typical leukocyte markers immunohistochemically as correlated to the promotion of PIN lesions.

METHODS

Adolescent rats received injections of PE (subcutaneously) (10 mg/kg BW/per day) and were euthanized 3, 8 hr, 1, 3, 7, 14 days thereafter. The dissected prostates were fixed in formalin, and paraffin embedded sections were cut and immunoreacted.

RESULTS

PE exerted a time related bi-phasic effect on the rat prostate. A first inflammatory reaction phase took place at 3-8 hr post injection characterized by vascular dilatation, congestion, edema, and massive leukocytic infiltrate, mainly of ED1+ cells. At 24 hr, the amount of ED1+ cells decreased approaching the equivalent values of ED2+, CD8+ cells, and mastocytes. Their values remained relatively high for the rest of the experimental period. A second phase of proliferative changes, consisting of healing fibrosis as well as dysplastic epithelial lesions, similar to human PIN lesions, appeared on the 7th day.

CONCLUSIONS

Neuro-immune interactions promote prostatic fibrosis and dysplastic changes; these being preceded by an acute and transient inflammatory reaction.

Therapeutic Approaches Targeting Prostate Cancer Progression Using Novel Voltage-Gated Ion Channel Blockers

The early detection and treatment of prostate cancer have increased survival and improved clinical outcomes. The nature of the disease and pathologic understaging result in a high proportion of patients developing locally recurrent disease or distant metastases. The development of prostate cancer the time from tumor initiation and progression to invasive carcinoma often begins in men in the fourth or fifth decades of life and extends across decades. This prolonged window highlights the tremendous clinical impact that early intervention with therapeutic agents that selectively target the invasive and metastatic potential of the prostate cancer cell could have on patient survival and quality of life. Our research is currently focused on the development and testing of novel voltage-gated ion channel blockers. The expression of voltage-gated sodium channels (VGSCs) was recently associated with the metastatic behavior of prostate cancer cells. In these studies, VGSC blockers altered prostate cancer cell morphology and arrested prostate cancer cell migration. Clinically, one of the most widely used sodium channel blockers is phenytoin. We have used rational drug design based on the phenytoin binding site in a VGSC to make novel sodium channel blockers with enhanced activity and minimal acute toxicity. Our initial studies in vitro demonstrate enhanced binding of the compounds to the sodium channel and increased inhibition of prostate cancer cell growth in culture and in soft agarose compared with phenytoin. These derivatives are currently being tested for their antitumor activity in human prostate cancer xenografts.

Rapid proliferation of prostatic epithelial cells in spontaneously hypertensive rats: a model of spontaneous hypertension and prostate hyperplasia

Spontaneously hypertensive rats (SHRs), a commonly used model of genetic hypertension, exhibit features of glandular hyperplasia of the ventral prostate, including the narrowing of acini with epithelial protrusions into the lumen and the piling up of epithelial cells. These rats also have frequent urinary voiding. In order to define the fundamental processes that lead to prostatic hyperplasia in SHRs, we compared the proliferation rate of their prostatic epithelial cells (PECs) in primary culture and in vivo to that of Wistar-Kyoto rats (WKYs), their normotensive controls. In vitro, primary cultures of SHR PECs had a shorter doubling time than those of WKY (3.3 vs 8.0 days) and showed higher levels of bromodeoxyuridine (BrdU) incorporation into DNA. In vivo, the BrdU incorporation seen 48 hours following injection was observed primarily in areas of epithelial piling up, which are seen in SHRs but not in WKYs. We concluded that prostate hyperplasia in SHRs results from a genuine increase in the proliferation rate of PECs and that this rapid proliferation is a fundamental feature of SHR PECs, maintained both in vivo and in vitro. Thus, SHRs can serve as a model for glandular hyperplasia of the prostate, resulting from a genetic tendency for an increased rate of cell proliferation.

Mechanistic investigation of the adrenergic induction of ventral prostate hyperplasia in mice

BACKGROUND

The norepinephrine (NE) analog phenylephrine has previously been shown to induce atypical prostate hyperplasia in rats. The objective of the present study was to provide further insight into the mechanism of phenylephrine-induced prostate growth.

METHODS

Adult male C57/BL6 mice were given daily subcutaneous injection of phenylephrine, isoproterenol, or phenylephrine in combination with BMY7378, cyclazosin, RS100329, or yohimbine, and the effects on ventral prostate histology, and proliferative and apoptotic indices determined. Phenylephrine was also administered in combination with testosterone in castrated mice.

RESULTS

Atypical prostatic hyperplasia characterized by piling up and/or papillary infolding of epithelial cells with concomitant stromal smooth muscle hyperplasia was seen in adult mice given subcutaneous injection of phenylephrine daily for 26 days. Phenylephrine induced hyperplasia was more severe proximally and was associated with significantly reduced rates of apoptosis (but no change in cell proliferation) in both stromal and epithelial compartments. Only the alpha(1A)-adrenoceptor selective subtype antagonist RS100329 abrogated the phenylephrine-induced hyperplasia. Using selective antibodies, the alpha(1A-1)-adrenoceptor subtype was predominantly localized to the stromal compartments of the mouse and rat ventral prostates. The effects of phenylephrine were mediated independent of testicular androgens.

CONCLUSIONS

Prostatic hyperplasia in mice occurs as a consequence of subchronic administration of the sympathomimetic phenylephrine. Response to phenylephrine is mediated by the alpha(1A)-adrenoceptor, which predominates in the stroma of the rodent ventral prostate. Conceivably, therefore, phenylephrine could directly modulate prostate stromal growth, and indirectly modulate epithelial growth in a paracrine fashion. We cannot, however, rule out the contribution of other indirect effects such as hypoxia/reperfusion or effects on intermediary metabolism.

Determination of percent area density of epithelial and stromal components in development of prostatic hyperplasia in spontaneously hypertensive rats

OBJECTIVES

To determine the percent area density of epithelial and stromal components in the development of prostatic hyperplasia in spontaneously hypertensive (SH) rats.

METHODS

The ventral lobes of prostates obtained from male SH rats and their normotensive counterparts, Wistar Kyoto (WKY) rats, were examined histopathologically at 15, 29, 40, and 54 weeks of age (5 SH and WKY rats each at each age group). The degree of prostatic hyperplasia was evaluated with a score-chart protocol, histoscore. The percent area density of epithelium and stroma of the ventral prostate were determined using a computerized image analysis system.

RESULTS

Definite lesions of hyperplastic changes were demonstrated in the ventral prostate of SH rats from 15 to 54 weeks. In comparison with WKY rats, SH rats showed a significantly increased degree of prostatic hyperplasia as reflected by the histoscore values. Furthermore, the histoscore of the ventral prostate of SH rats increased with age (from 21.7 +/- 0.7 at 15 weeks to 26.1 +/- 0.4 at 54 weeks). The percent area density of epithelium and stroma were significantly increased in SH rats, and the ratio of stroma to epithelium ranged from 1:2.94 to 1:3.50 in SH rats but was maintained at 1:1.15 to 1:1.19 in WKY rats during the observation period.

CONCLUSIONS

The hyperplastic changes of the ventral prostate may develop with advancing age in SH rats. The development of prostatic hyperplasia may result from both epithelial and stromal proliferation and may be predominantly expressed as a glandular type in SH rats.

Does the prostatic vascular system contribute to the development of benign prostatic hyperplasia?

Benign prostatic hyperplasia (BPH) is a disease condition characterized by abnormal prostate growth in conjunction with distinct lower urinary tract symptoms. This paper considers the extent to which the prostatic vascular system contributes to normal prostate growth control as well as whether abnormal blood flow patterns in the aging prostate gland might lead to hypoxia-stimulated prostate growth. This relationship is posited from accumulated research that suggests the prostatic vascular system is a primary androgen action target and other research demonstrating the diverse effects of hypoxia in eliciting cell death or cell growth responses. This hypothesis is further supported by the coincidental clinical finding that the presence of cardiovascular disease conditions are among the general risk factors for the development of BPH, and that cardiovascular-active drugs can be used for the treatment of BPH symptoms. This hypothesis has major implications for our understanding of the etiology of BPH, as well as for the development of new and better treatments for this extremely common condition.

Evaluation of the adequacy of published studies of low-dose effects of bisphenol A on the rodent prostate for use in human risk assessment

Studies conducted in our laboratories and by others found no consistent correlation between prostate size, prostate pathology, or the development of prostate cancer under a variety of experimental conditions. Furthermore, an evaluation of eight published studies that were conducted in mice and rats following in utero exposure by oral treatment of dams with low levels of bisphenol A (BPA) and that focused on the prostate identified several discrepancies that affect their adequacy for use in human risk assessment. For example, there was inadequate reporting of the purity of BPA and the animal supplier used, and housing of offspring was not the same among the studies. In addition, there were differences between studies with mice and rats in exposure regimen, route of exposure, and numbers of dams or pups used per BPA dose group. Poor inter- and intraspecies correlation (i.e., mouse to rat or between mouse or rat strains) further complicates the ability to use results from these studies to predict potential prostate effects in humans. Thus, we conclude that a finding of increased prostate weight in rodent studies with perinatal exposure in the absence of associated pathologic and/or functional changes is meaningless and not indicative of a potential adverse effect in humans.

Cadmium chloride-induced dysplastic changes in the ventral rat prostate: an immunohistochemical and quantitative study

BACKGROUND

Cadmium chloride is an environmental toxic that might be implicated in human prostate carcinogenesis. The study was directed: 1) to evaluate the immunoexpression of markers for cell proliferation, apoptosis, and resistance to apoptosis, and 2) to estimate the size of premalignant cell population in the preneoplastic changes induced in ventral prostates of rats treated with cadmium chloride administered in drinking water.

METHODS

The following parameters were calculated in the ventral prostatic lobe of normal rats and rats that received cadmium in drinking water during 18 months: total volume, epithelial volume, total number of epithelial cells, numerical density of epithelial cells, percentage of cells that immunostained to the proliferating cell nuclear antigen (PCNA), percentage of apoptotic cells (evaluated by a DNA fragmentation method), and absolute volume and volume fraction of immunostaining to bcl-2.

RESULTS

The percentage of PCNA immunoreactive nuclei, the bcl-2 expression, and the numerical density of epithelial cells were significantly (P < 0.05) increased in the dysplastic prostatic acini of treated rats in comparison with the normal acini of treated rats and control animals. The percentage of apoptotic nuclei from ventral dysplastic acini was significantly (P < 0.05) decreased in comparison with that of normal acini. A negative correlation between proliferation and apoptosis was found in dysplastic lesions.

CONCLUSIONS

Prostate epithelial dysplasia induced in rats by cadmium presents an increased proliferative activity and high expression of bcl-2 protein, as was described in human prostate intraepithelial neoplasia. However, the rate of apoptosis in rat dysplasia was importantly decreased, in contrast to that observed in some human preneoplastic changes. This decrease might be related to the increase of bcl-2 expression.

Tyrosine kinase A, autonomic and transmitter receptors, but not innervation, are upregulated in the aging rat prostate

In the mature rat ventral prostate, epithelial proliferation is accompanied by significant upregulation of tyrosine kinase A, alpha1B and muscarinic acetylcholine M2 receptors as well as the synaptic vesicle-associated membrane proteins synaptobrevin and SV2 as compared with immature prostate tissue. The adrenergic receptors beta1, alpha2A and alpha1 were also up-regulated and translocated in mature rat prostate tissue. Expression of the Schwann cell/axonal marker S100 remained unchanged. These results are suggestive of a marked increase in metabolic activity, calcium influx and autonomic receptor expression in the aging prostate. These changes were not accompanied by an increase in the number of axons.

Serum and semen prostate specific antigen concentrations are different in young spinal cord injured men compared to normal controls

PURPOSE

Recent investigations have indicated that factors within the seminal plasma may contribute to the condition of low sperm motility in men with spinal cord injury. To determine whether the prostate gland functions normally in these men we chose prostate specific antigen (PSA) as a marker of prostatic function, and compared serum and semen concentrations in spinal cord injured and healthy noninjured men.

MATERIALS AND METHODS

The study included 21 spinal cord injured men (mean age 33.3+/-1.2 years) and 22 noninjured normal men (mean age 30.3+/-1.5 years). Blood was obtained from subjects following at least 24 hours of abstinence from ejaculation and serum PSA was determined by modified enzyme immunoassay. Antegrade ejaculates from all subjects were frozen to -80 C, exactly 15 minutes after collection. Seminal plasma PSA was determined using Hybritech Tandem MP assay.

RESULTS

Mean serum PSA concentration was 1.20+/-0.19 ng./ml. in spinal cord injured and 0.69+/-0.07 ng./ml. in noninjured men (p<0.02). Mean seminal plasma PSA concentration was 0.59+/-0.11 mg./ml. in spinal cord injured and 1.29+/-0.15 mg./ml. in noninjured men (p<0.001).

CONCLUSIONS

Our findings of elevated serum and decreased seminal plasma PSA concentrations indicate that prostatic secretory dysfunction is present in men with spinal cord injury.