Long-term inhibition of 5-alpha reductase and aromatase changes the cellular and extracellular compartments in gerbil ventral prostate at different postnatal ages

Prostatic morphological changes throughout life: Cytochemistry as a tool to reveal tissue aging markers

The prostate undergoes normal or pathological morphological changes throughout life. An understanding of these changes is fundamental for the comprehension of aging-related pathological processes such as benign prostatic hyperplasia (BPH) and cancer. In the present study, we show some of these morphological changes, as well as histochemical techniques like Weigert's resorcin-fuchsin method, Picrosirius Red, and Gömöri's reticulin for use as tools in the study of prostate tissue under light microscopy. For this purpose, prostates of the Mongolian gerbil (n = 9), an experimental model that develops BPH spontaneously, were analyzed at three life stages: young (1 month old), adult (3 months old), and old (15 months old). The results showed that fibrillar components such as collagen, and reticular and elastic fibers, change throughout life. In young animals, the prostate has cuboidal epithelium surrounded by thin layers of smooth muscle, continuous collagen fibers, winding reticular fibers, and sporadic elastic fibers. With adulthood, the epithelium becomes columnar, encircled by compacted muscle cells among slender collagen fibers, elongated reticular fibers, and linear elastic fibers. In aging individuals, the prostate's epithelium stratifies, surrounded by thick muscle layers among dense collagen fibers, disordered reticular fibers, and elastic fibers in different planes. We also identified a few accumulations of lipid droplets and lipofuscin granules in adult animals and high accumulation in old animals evidenced by Oil red O and Gömöri-Halmi techniques, respectively. The histochemical techniques presented here have been demonstrated to be useful and accessible tools in prostate studies. RESEARCH HIGHLIGHTS: Cytochemical techniques to study prostate morphology. The prostate changes with age.

Aging effects in adrenal cortex of male Mongolian gerbil: A model for endocrine studies

The adrenal gland produces steroid hormones that act in the homeostasis of organisms. During aging, alterations in the hormonal balance affect the adrenal glands, but these have not yet been fully described due to the lack of adequate animal models. The adrenal gland of the Mongolian gerbil has a morphology similar to the primate's adrenal gland, which makes it a possible animal model for endocrine studies. Therefore, the current study aimed to study the morphophysiology of the adrenal gland under the effect of aging. For this purpose, males Meriones unguiculatus, aged three, six, nine, twelve, and fifteen months were used. Morphometric, immunohistochemical, and hormonal analyses were performed. It was observed that during aging the adrenal gland presents hypertrophy of the fasciculata and reticularis zones. Lipofuscin accumulation was observed during aging, in addition to changes in proliferation, cell death, and cell receptors. The analyses also showed that the gerbil presents steroidogenic enzymes and the production of steroid hormones, such as DHEA, like that found in humans. The data provide the first comprehensive assessment of the morphophysiology of the Mongolian gerbil adrenal cortex during aging, indicating that this species is a possible experimental model for studies of the adrenal gland and aging.

Prenatal exposure to finasteride promotes sex-specific changes in gerbil prostate development

Finasteride is a drug that is widely used in the treatment of benign prostatic hyperplasia, hair loss and even as a chemotherapeutic agent in the treatment of prostatic adenocarcinoma. However, its use is known to cause several side effects in adults and it can also cause changes in the embryonic development of the male prostate, which is a cause for concern given the possibility of the accumulation of finasteride in the environment. Nevertheless, no studies have investigated the effects of finasteride on the development of the prostate in females, which occurs in several species of mammals. To evaluate the effects of intrauterine exposure to finasteride (500μgkg-1 day-1) on postnatal prostate development in the Mongolian gerbil in the present study, we used immunohistochemistry, immunofluorescence, serological analysis and three-dimensional reconstruction techniques. Differences were observed in the effects of finasteride on periductal smooth muscle and cell proliferation between the sexes, as well as intersex differences in the presence of the androgen receptor, which was elevated in males, and the oestrogen receptor ERα, which was increased in females. Together, the data indicate that the female prostate has its own hormone dynamics and that there are sex-specific differences in the way in which the female prostate reacts to prenatal exposure to finasteride.

Postnatal exposure to finasteride causes different effects on the prostate of male and female gerbils

The development and maintenance of prostate function depend on a fine balance between oestrogen and androgen levels. Finasteride inhibits 5α-reductase, which is responsible for the conversion of testosterone into its most active form, dihydrotestosterone. Enzymes that metabolize these hormones have a highly relevant role in both the normal prostate metabolism and in the occurrence of pathological conditions. There are few studies on the impact of finasteride on male prostate development and fewer studies on the female prostate and possible intersexual differences. Therefore, we treated male and female gerbils from 7 to 14 days in postnatal life with a high dose of finasteride (500 μg/kg/day); the prostate complexes were then removed and submitted to immunohistochemistry, immunofluorescence and three-dimensional reconstruction. In addition, hormonal serum dosages were administered. Treatment with finasteride resulted in an increased thickness of the periductal smooth musculature in the prostate of both male and female gerbils, such as well as a reduction in the thickness of developing prostate alveoli in both sexes. In addition, intersexual differences were observed as increased epithelial proliferation and decreases in the number of developing alveoli in females. Together, the data indicate that postnatal exposure to finasteride causes greater changes in the female gerbil prostate than in the male.

Short-term exposure to chrysin promotes proliferative responses in the ventral male prostate and female prostate of adult gerbils

Chrysin (5,7-dihydroxyflavone) is a bioactive compound found in different fruits, vegetables, honey and propolis. This flavone has been suggested for the treatment of reproductive dysfunction, mainly because of its antioxidant and hormonal properties. However, the effects of this polyphenol on the prostate are still poorly understood. The purpose of this study was to evaluate the effects of short-term chrysin exposure on the ventral male and female prostates of adult gerbils. To evaluate the androgenic potential of chrysin, gerbils were also exposed to testosterone. Male and female gerbils were exposed to chrysin (50 mg/kg/day, orally) or testosterone cypionate (1 mg/kg/week, subcutaneously) for 3, 7 and 21 days. Prostates were dissected for morphological, stereological and immunohistochemical analyses. Serum levels of testosterone and 17β-estradiol were measured by ELISA. Serum testosterone levels were not increased by chrysin supplementation in males or females. However, only females treated with chrysin for 21 days showed an increase in estradiol levels. Increased androgen receptor immunoreactivity, higher proliferation rates and glandular hyperplasia were observed in male and female prostates for all chrysin treatment times. Additionally, increased oestrogen receptor alpha immunoreactivity was observed in all chrysin-treated females. Although chrysin and testosterone promoted similar morphological changes in the gerbil prostate, chrysin supplementation was less deleterious to prostate health, since it resulted in lower incidence of hyperplasia and an absence of neoplastic foci.

Fibrillar collagen genes are not coordinately upregulated with TGF β1 expression in finasteride-treated prostate

Benign prostatic hyperplasia (BPH) is the most common cause of lower urinary tract symptoms (LUTS) in older men. In this regard, recent studies have attempted to define the relationships between prostatic fibrosis, LUTS, and increased expression of transforming growth factor β1 (TGF β1) in BHP. Therapeutic approaches for BPH such as 5-α-reductase inhibitors and alpha-adrenergic blocking agents increase TGF β1 expression in the prostatic tissue. Here, we investigated the effects of the 5-α-reductase inhibitor-finasteride-on rat ventral prostate tissue, especially with regard to the tissue distribution and gene expression of fibrillar collagens. Adult Wistar rats (n = 15) were treated with finasteride (25 mg/kg/day) by subcutaneous injection for 7 and 30 days. Age-matched, vehicle-treated (n = 15) adult Wistar rats were used as control. Finasteride treatment reduced prostate size and increased the area of types I and III collagen fibers in the prostatic stroma. As expected, TGF β1 mRNA expression was upregulated by finasteride treatment. However, COL1A1 and COL3A1 mRNA expressions decreased after both 7 and 30 days of finasteride treatment, suggesting that finasteride treatment promotes prostate parenchyma and stroma changes, which lead to the observed types I and III collagen remodeling without de novo collagen synthesis. The upregulation of TGF β1 mRNA and protein associated with the 5-α-reductase inhibitor is more closely related to epithelial and stromal cell death pathways than to prostatic fibrosis.

Prenatal testosterone exposure as a model for the study of endocrine-disrupting chemicals on the gerbil prostate

The development of the prostate depends on a precise androgenic control, so sensible interferences may predispose this gland to develop prostatic diseases during life. These aspects are of interest and preoccupation, since human beings are exposed to a growing number of endocrine-disrupting chemicals with androgenic potential. Therefore, our aim was to evaluate the prostates of adult gerbils exposed to testosterone during intrauterine life. Serological, morphological, morphometric-stereologic, immunohistochemical and three-dimensional reconstruction analyses were used. We found that the testosterone effects were dose-dependent and more harmful to females, leading to the development of masculine characteristics, evidenced by an increased anogenital distance, and absence of vaginal opening and the ectopic development of prostatic tissue. Moreover, premalignant lesions, such as prostatic intraepithelial neoplasia, were observed in addition to inflammatory foci in the prostate. The results showed that the prenatal exposure to testosterone may affect the reproductive system, disrupting developmental processes and increasing susceptibility to the development of prostatic diseases in the Mongolian gerbil.

Finasteride in Hidradenitis Suppurativa: A "Male" Therapy for a Predominantly "Female" Disease

OBJECTIVE

Hidradenitis suppurativa is associated with obesity and metabolic syndrome, and a hormonal component has been implicated. Finasteride is an anti-androgenic agent used for benign prostatic hypertrophy, androgenic alopecia, and, in females, hirsutism. Finasteride is an inhibitor of type II5 alpha-reductase that reduces dihydrotestosterone levels and appears to alter end-organ sensitivity of the folliculopilosebaceous unit. The objective is to review the use of finasteride for hidradenitis suppurativa.

DESIGN

Review of the literature.

SETTING

Clinical treatment of patients with hidradenitis suppurativa. Measurement/participants: Five publications described the use for hidradenitis suppurativa. Four global case reports cited 13 individual patients, four male and nine female. Females included three adolescent patients and a child aged seven with precocious puberty. In the United States, finasteride in obese male adults was mentioned to be helpful.

RESULTS

Oral finasteride, as monotherapy or additional therapy was utilized for advanced hidradenitis suppurativa. The outcomes were largely favorable, with complete resolution in three patients. A latency period was evident in a majority. Limited, or continuous use for up to six years, was detailed. Response to reintroduction was successful. A benign safety profile with excellent tolerability was described. Teratogenicity of finasteride was addressed and contraception advocated in female patients. Sexual adverse effects were not ascertained.

CONCLUSION

In hidradenitis suppurativa, finasteride could be considered in adults of both sexes as well as in select female children and adolescents, particularly those with concurrent metabolic and hormonal alterations present. Finasteride provides another highly effective, durable, relatively safe, and inexpensive option in the treatment of hidradenitis suppurativa.

Absence of effects on the rat sperm quality after subacute exposure to low doses of fungicide prochloraz

Prochloraz (PCZ) is a fungicide and androgen-receptor antagonist used worldwide in horticulture and agriculture. Pre- and perinatal exposure to this pesticide during sexual differentiation is deleterious for male offspring. Since data on the effects of PCZ on epididymal functions are scarce, and because sperm maturation occurs in this organ, the present investigation aimed to determine whether low PCZ doses administered to rats during the phase of sperm transit through the epididymis might affect the morphophysiology of this organ and sperm quality. Adult male Wistar rats were assigned to 4 different groups: 0 (control, vehicle) or 10, 15, or 30 mg/kg bw/d PCZ diluted in corn oil administered orally for 4 consecutive days. Morphofunctional parameters of the male reproductive tract, hormone concentrations, sperm evaluations, and fertility and histopathologic analysis of testis and epididymis were assessed. There were no statistically significant differences between treated and control groups in relation to all evaluated parameters. Data demonstrated show that PCZ exposure for a brief 4-d exposure and low doses did not produce reproductive toxicity or compromise sperm quality in adult rats.

Budding process during the organogenesis of the ventral prostatic lobe in Mongolian gerbil

The prostate is a mammalian gland that shows a complex process of organogenesis. Here, a morphological study to characterize the organogenesis of the ventral prostate lobe in male gerbils was conducted. The urogenital sinus (UGS) was dissected out and processed for paraffin embedding. Histological sections were subjected to cytochemical, immunofluorescence, immunohistochemical, and three-dimensional reconstruction techniques. We found that the first ventral buds emerged from the ventral urethral epithelium between the days 20 and 21 of prenatal life, reaching the ventral mesenchymal pad and initiating the branching process on the first day of postnatal life. The buds presented a V-shaped elongation, suggesting that the smooth muscle layer (SML) plays an important role during budding events. Indeed, whereas the androgen receptor (AR) was preferentially found in the UGS mesenchyme (UGM), estrogen receptor alpha (ERα) was localized in both the UGM and in the emerging buds. This study characterized the morphological aspects of the budding process in a different rodent from rat and mice, serving as a new model for future studies on developmental biology of the prostate.

5α-reductases in human physiology: an unfolding story

OBJECTIVE

5α-reductases are a family of isozymes expressed in a wide host of tissues including the central nervous system (CNS) and play a pivotal role in male sexual differentiation, development and physiology.

METHODS

A comprehensive literature search from 1970 to 2011 was made through PubMed and the relevant information was summarized.

RESULTS

5α reductases convert testosterone, progesterone, deoxycorticosterone, aldosterone and corticosterone into their respective 5α-dihydro-derivatives, which serve as substrates for 3α-hydroxysteroid dehydrogenase enzymes. The latter transforms these 5α-reduced metabolites into a subclass of neuroactive steroid hormones with distinct physiological functions. The neuroactive steroid hormones modulate a multitude of functions in human physiology encompassing regulation of sexual differentiation, neuroprotection, memory enhancement, anxiety, sleep and stress, among others. In addition, 5α -reductase type 3 is also implicated in the N-glycosylation of proteins via formation of dolichol phosphate. The family of 5α-reductases was targeted for drug development to treat pathophysiological conditions, such as benign prostatic hyperplasia and androgenetic alopecia. While the clinical use of 5α-reductase inhibitors was well established, the scope and the magnitude of the adverse side effects of such drugs, especially on the CNS, is still unrecognized due to lack of knowledge of the various physiological functions of this family of enzymes, especially in the CNS.

CONCLUSION

There is an urgent need to better understand the function of 5α-reductases and the role of neuroactive steroids in human physiology in order to minimize the potential adverse side effects of inhibitors targeting 5α-reductases to treat benign prostatic hyperplasia and androgenic alopecia.

Structural and ultrastructural evidence for telocytes in prostate stroma

The prostate comprises a glandular epithelium embedded within a fibromuscular stroma. The stroma is a complex arrangement of cells and extracellular matrix (ECM) components in addition to growth factors, regulatory molecules, remodelling enzymes, blood vessels, nerves and immune cells. The principal sources of ECM components are fibroblasts and smooth muscle cells (SMC), which synthesize the structural and regulatory components of the ECM. Telocytes (TCs) were recently described as a novel stromal cell type that exhibited characteristic features. The aim of this study was to confirm the presence of TCs in prostate stromal tissue of gerbils, as the stromal compartment of this gland is a dynamic microenvironment. We used transmission electron microscopy (TEM), light microscopy and immunohistochemistry methods to provide morphological evidence for the presence of TCs. Cells that resembled TCs were observed in gerbil prostatic stroma. These cells had small cellular bodies with very thin and extremely long cellular processes. They were found primarily in the subepithelial area and also at the periphery of SMC layers. TCs also exhibited moniliform processes, caveolae and nuclei surrounded by small amounts of cytoplasm. Close contacts between TC podomers were evident, particularly in the adjacent epithelial compartment. This morphological evidence supported the presence of TCs in the gerbil prostatic stroma, which we report for the first time.

High fat-induced obesity associated with insulin-resistance increases FGF-2 content and causes stromal hyperplasia in rat ventral prostate

Obesity affects sex hormone secretion, which can negatively influence prostatic structure, homeostasis, and disease. This investigation aimed to evaluate the repercussions of obesity induced by a high-fat diet on the rat prostate, with or without treatment with the aromatase inhibitor, Letrozole. Adult Wistar rats were fed a high-fat diet (20% saturated fat, O) for 15 weeks to induce obesity or received a balanced diet (4% fat, C). Then, a group of C and O rats were daily treated with Letrozole (1 mg/kg b.w. per day) for 2 weeks (CL and OL, respectively). Subsequently, ventral prostate was processed for analysis by transmission electron microscopy, immunohistochemistry, and Western blotting. Obesity decreased 70% of the testosterone plasma level. The prostate showed epithelial atrophy and dilated acini in the intermediate portion and epithelial wrinkling in the distal tips. The relative frequency of smooth muscle α-actin in the O group increased by 67%. Ultrastructurally, epithelial cells in obese animals presented altered secretory organelles, lipid droplets, and thicker subjacent fibromuscular layer. Letrozole treatment caused a partial restoration of the prostatic changes caused by obesity. Obesity increased the prostatic content of fibroblast growth factor-2 (FGF-2) by 150%, and Letrozole treatment increased this protein even more in the control and obese groups. This investigation shows that obesity provokes structural and ultrastructural changes in the epithelium of rat prostate; these changes might affect gland homeostasis and physiology. The epithelial and smooth muscle cell hyperplasia and increased FGF-2 expression observed in this experimental model of obesity/insulin-resistance might explain the high frequency of benign prostatic hyperplasia in insulin-resistant men.

Incomplete recovery of erectile function in rat after discontinuation of dual 5-alpha reductase inhibitor therapy

AIM

The association of 5-alpha reductase inhibitor (5ARI) therapy and sexual dysfunction has been reported. Some patients claim persistent erectile dysfunction despite long-term discontinuation of 5ARI treatment. The aim of this study was to assess erectile function after cessation of 5ARI therapy using a rat model.

METHODS

Twenty-six adult male Sprague-Dawley rats were randomized into three groups: (i) control (N = 10); (ii) 8-week dutasteride treatment (0.5 mg/rat/day, in drinking water, N = 8); and (iii) 6-week dutasteride treatment followed by a 2-week washout period (N = 8). The experiments were performed after 8 weeks from the initiation of treatment in all groups. In vivo erectile activity and in vitro contractile and relaxant responses of cavernosal smooth muscle were investigated.

RESULTS

In vivo erectile activity (intracavernosal pressure [ICP]/mean arterial pressure [MAP] and total ICP) in treatment groups were significantly decreased compared with controls (ICP/MAP: P < 0.001 for 2.5 v, 5 v, and 7.5 v; total ICP: P < 0.001 for 5 v and P < 0.01 for 7.5 v). Acetylcholine-induced relaxations were diminished in treatment groups (P < 0.05). Relaxant responses to electrical field stimulation (EFS) were decreased in the 8-week treatment group (P < 0.05) but were similar to controls in the washout group. Sodium nitroprusside (SNP)-induced endothelium-independent relaxations were reduced in the 8-week dutasteride treatment group (P < 0.01), while these responses were restored in the washout group. The contractile responses to the alpha1-adrenergic agonist phenylephrine were decreased in treatment groups compared with controls (P < 0.01). Direct neurogenic contractile responses in the dutasteride groups were significantly lower than controls between 1 and 15 Hz frequencies (but not at 20 Hz) and washout partially restored the responses at 10 and 15 Hz.

CONCLUSION

Discontinuation of dutasteride improved the relaxant responses to EFS and SNP, while cholinergic and adrenergic responses remained depressed. Our findings suggest a time-dependent detriment of dutasteride on erectile function. The withdrawal/washout effect of 5ARIs on parameters of human sexual function warrants further investigation.

Morphometric-stereological and functional epididymal alterations and a decrease in fertility in rats treated with finasteride and after a 30-day post-treatment recovery period

OBJECTIVE

To evaluate morphometric-stereological changes in the epididymal caput, sperm quality, and fertility parameters in rats treated with finasteride and after a 30-day post-treatment recovery period.

DESIGN

Experimental study in a research laboratory.

SETTING

Reproductive biology research laboratory.

ANIMAL(S)

Male and female Sprague Dawley rats.

INTERVENTION(S)

Treatment with finasteride (5 mg/kg/day) for 56 days followed by 30 days without treatment.

MAIN OUTCOME MEASURE(S)

Serum hormone analyses, morphometric-stereological and ultrastructural evaluation of the epididymal caput, sperm transit time, natural mating, in utero insemination, sperm membrane integrity, and fertility parameters.

RESULT(S)

Serum dihydrotestosterone levels in the finasteride group decreased by ~40% compared with that of control rats. Ultrastructural analysis revealed significant reductions in several morphometric-stereological parameters of the epididymal caput. All parameters recovered significantly in the post-treatment period. There was no alteration in daily sperm production in the finasteride group. However, significant reductions in sperm transit time, motility, sperm membrane integrity, and fertility parameters were observed in rats treated with finasteride.

CONCLUSION(S)

Treatment with finasteride caused morphometric-stereological and functional changes in the epididymis and in sperm function that led to a reduction in fertility parameters. A 30-day post-treatment recovery period was insufficient to restore normal sperm motility, sperm transit time, and some fertility parameters.

Increased androgen receptor and remodeling in the prostatic stroma after the inhibition of 5-alpha reductase and aromatase in gerbil ventral prostate

Prostate require high levels of steroidogenic enzymes such as 5alpha-reductase (5alpha-r) and Aromatase (Aro) for the formation of active steroids. Dihydrotestosterone (DHT), the prostate dominant androgen, is converted from testosterone (T) by the action of 5alpha-r. Aro provides an alternative pathway for estrogen, via T aromatization. Since prostatic maintenance is dependent on both reciprocal stromal-epithelial interaction and regulation by steroids, this study aimed to elucidate what the absence of 5alpha-r and Aro enzymes provokes in the prostate microenvironment after their long-term inhibition. Data obtained 1 day after the 30 consecutive days of enzymatic inhibition with Finasteride (5alpha-r inhibitor) and Letrozole (Aro inhibitor) demonstrated a marked stromal remodeling, with an increased deposition of extracellular matrix (ECM) proteins besides androgen receptor (AR) overexpression in the three phases of postnatal development analyzed. The subepithelial area of acini from ventral prostate presented collagen and reticular fibers accumulation, besides various altered and active fibroblasts. The AR content immunostaining was elevated after enzymatic inhibition therapy, mainly in the nuclei of epithelial cells. Similar data were observed in the ventral prostates even 21 days after the end of treatments. Results obtained following the long-term inhibition of 5alpha-r and Aro are relevant and highlight the actions of these enzymes as crucial not only for the maintenance of tissue architecture and ECM arrangement but also for androgen and AR function. The long-term absence of their action imposes a novel situation on the prostate from which its normal physiology could not be restored by the conclusion of the treatments.

Modulação androgênica e estrogênica na próstata: uma abordagem em modelos experimentais de roedores com enfoque na biologia estrutural

O sistema endócrino é uma complexa rede de glândulas e hormônios que regulam muitas das funções do corpo, incluindo crescimento, desenvolvimento e maturação, como as vias de ação de muitos órgãos. A próstata é um importante alvo dos hormônios e sua maturidade funcional e seu desenvolvimento são influenciados pelos níveis de esteroides. O presente grupo de pesquisa tem estudado os potenciais efeitos dos agentes esteroides sobre a próstata masculina e feminina do gerbilo da Mongólia (Meriones unguiculatus), utilizando métodos morfológicos e imuno-histoquímicos. Os resultados têm revelado a próstata do gerbilo da Mongólia como uma importante ferramenta para estudos da ação dos hormônios esteroides e seus antagonistas.