Androgen and estrogen receptors in the human corpus cavernosum penis: immunohistochemical and cell culture results

Androgen Receptor Signaling is Similar in Human Corpus Cavernosum in Men with Different Serum Testosterone Levels

BACKGROUND

Testosterone (T) plays an important role in male reproductive function and tissue development. Normal serum T levels vary between 300 and 1000 ng/dl. It is not known, however, if varying serum T levels alter androgen receptor (AR) signaling in tissue.

OBJECTIVE

To measure AR signaling levels in human corpus cavernosal tissue in males with different serum T levels.

DESIGN, SETTING, AND PARTICIPANTS

Participants were selected from a group of males undergoing surgical management for erectile dysfunction (ED; penile prosthesis placement). T levels were measured 1 week before surgery and a sample of corpus cavernosal tissue was procured during surgery. The tissue was homogenized, measured for protein concentration, and used for western blot analysis. VEGF was selected as an AR marker and actin was used for protein normalization.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

VEGF and actin expression levels were analyzed using western blot analysis and ImageJ was used for quantification of antibody expression.

RESULTS AND LIMITATIONS

AR signaling was measured in terms of VEGF expression. Above a T level of 200 ng/dl, there was no significant difference found in VEGF expression. Only one patient had a T level less than 200 ng/dl, limiting the generalizability of these results. In addition, all patients had a history of ED, and controls (patients without ED) were not included in the study.

CONCLUSIONS

Above a serum T level of 200 ng/dl, there was no significant difference in AR signaling. This finding suggests that there could be a saturation level present in corpus cavernosal tissue that is approximately 200 ng/dl.

PATIENT SUMMARY

Serum testosterone levels above a certain threshold may not be necessary for biological functions. Instead, it is most likely that there is an approximate serum testosterone level that fully saturates tissue androgen receptors and results in peak function in men.

Physiological roles of hydrogen sulfide in mammalian cells, tissues and organs

H2S belongs to the class of molecules known as gasotransmitters, which also includes nitric oxide (NO) and carbon monoxide (CO). Three enzymes are recognized as endogenous sources of H2S in various cells and tissues: cystathionine g-lyase (CSE), cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (3-MST). The current article reviews the regulation of these enzymes as well as the pathways of their enzymatic and non-enzymatic degradation and elimination. The multiple interactions of H2S with other labile endogenous molecules (e.g. NO) and reactive oxygen species are also outlined. The various biological targets and signaling pathways are discussed, with special reference to H2S and oxidative posttranscriptional modification of proteins, the effect of H2S on channels and intracellular second messenger pathways, the regulation of gene transcription and translation and the regulation of cellular bioenergetics and metabolism. The pharmacological and molecular tools currently available to study H2S physiology are also reviewed, including their utility and limitations. In subsequent sections, the role of H2S in the regulation of various physiological and cellular functions is reviewed. The physiological role of H2S in various cell types and organ systems are overviewed. Finally, the role of H2S in the regulation of various organ functions is discussed as well as the characteristic bell-shaped biphasic effects of H2S. In addition, key pathophysiological aspects, debated areas, and future research and translational areas are identified A wide array of significant roles of H2S in the physiological regulation of all organ functions emerges from this review.

Culture and purification of SD rat corpus cavernosum endothelial cells by enzymatic digestion combined with mechanical extrusion and fixed-point digestion

To explore a new method of in vitro culture and purification of rat corpus cavernosum endothelial cells (CCECs). Male Sprague-Dawley rats' penile tissue were digested with elastase or collagenase combined with mechanical extrusion to isolate and culture the CCECs. The fixed-point digestion method was used to purify the primary cells. High-purity CCECs were successfully isolated. Following the digestion of the primary CCECs by elastase or collagenase coupled with mechanical extrusion, the cells were paving stone- and cobblestone-shaped over 10 days. The cell purity yielded in the second generation (P2) CCECs after using the fixed-point digestion method was significantly high. Compared with primary CCECs extracted by elastase digestion combined with the mechanical extrusion method, CCECs cultured by collagenase digestion yielded higher purity and a more stable morphology after fixed-point digestion and purification. Immunofluorescence staining of the third generation CCECs and the expression results of endothelial cell-associated marker antibodies CD31 and VWF were positive, and flow cytometry showed the purity of CCECs was 96.9%. Enzymatic digestion combined with mechanical extrusion and fixed-point digestion is a simple, economical method for in vitro culture and purification of CCECs, which is conducive to studying the pathophysiological mechanisms of endothelial dysfunction and erectile dysfunction.

Role of Glucose-Lowering Medications in Erectile Dysfunction

Erectile dysfunction (ED) is a long-term complication of type 2 diabetes (T2D) widely known to affect the quality of life. Several aspects of altered metabolism in individuals with T2D may help to compromise the penile vasculature structure and functions, thus exacerbating the imbalance between smooth muscle contractility and relaxation. Among these, advanced glycation end-products and reactive oxygen species derived from a hyperglycaemic state are known to accelerate endothelial dysfunction by lowering nitric oxide bioavailability, the essential stimulus of relaxation. Although several studies have explained the pathogenetic mechanisms involved in the generation of erectile failure, few studies to date have described the efficacy of glucose-lowering medications in the restoration of normal sexual activity. Herein, we will present current knowledge about the main starters of the pathophysiology of diabetic ED and explore the role of different anti-diabetes therapies in the potential remission of ED, highlighting specific pathways whose activation or inhibition could be fundamental for sexual care in a diabetes setting.

Histologic Findings in Surgical Pathology Specimens From Individuals Taking Feminizing Hormone Therapy for the Purpose of Gender Transition: A Systematic Scoping Review

CONTEXT.—

Transgender women experience health disparities in all areas of medicine. Within surgical pathology, knowledge gaps relating to the concepts of transgender care exist. Medical transition for transgender women and transfeminine persons may involve hormone therapy and/or surgery to feminize the body. Understanding the common histologic changes in specimens from feminizing surgeries, as well as other specimens from patients on feminizing hormone therapy, will aid surgical pathologists in providing better care to this unique patient population.

OBJECTIVE.—

To summarize histologic findings in surgical pathology specimens from transgender women taking feminizing hormones.

DATA SOURCES.—

A systematic review of the OVID Medline and PubMed databases was performed to identify all studies describing histologic findings in surgical pathology specimens from transgender women from 1946 to 2019.

CONCLUSIONS.—

Much of the literature to date describing histologic findings in transgender women comes from the examination of genitourinary specimens removed during feminizing surgeries. Common benign changes associated with feminizing hormone therapy include the development of acini and lobules in the breast, testicular tubular changes, and squamous metaplasia of the prostate and urethra. Neoplastic cases include breast adenocarcinoma and fibroepithelial lesions, testicular germ cell tumors, prostatic adenocarcinoma, anal squamous cell carcinoma, pituitary adenomas, and meningiomas. Additional studies assessing the findings in other organ systems as well as population-based studies assessing rates of neoplasia are needed. However, future research relies on engagement within the surgical pathology community as well as collaboration with clinicians and patients to achieve optimal results.

Markers of Prenatal Androgen Exposure Correlate With Online Sexual Compulsivity and Erectile Function in Young Men

Pornography addiction and sexual dysfunction are increasingly prevalent in young men. Previous studies suggest that prenatal androgen exposure plays a role in addiction and sexual functionality. Here, we tested whether lower second-to-fourth finger length ratio (2D:4D) and later age at spermarche, both putative indicators of higher androgen levels in utero, correlate with online sexual compulsivity (OSC scale of ISST), erectile function (IIEF-5), and ejaculatory control (PEPA) in 4,370 young men (age IQR: 25-26 years) of the Cohort Study on Substance Use Risk Factors. Statistical analyses revealed that lower 2D:4D correlated with higher scores on the OSC scale. Moreover, higher age at spermarche correlated with higher OSC scores and decreased erectile function. Interestingly, OSC severity, but not the frequency of pornography use, correlated negatively with erectile function and ejaculatory control. This is the first study to associate two independent proxies of prenatal testosterone level with OSC. These findings provide novel insight into intrauterine predisposition of sexual behavior and related sexual function in adulthood.

The Role of Androgen Signaling in Male Sexual Development at Puberty

Puberty is characterized by major changes in the anatomy and function of reproductive organs. Androgen activity is low before puberty, but during pubertal development, the testes resume the production of androgens. Major physiological changes occur in the testicular cell compartments in response to the increase in intratesticular testosterone concentrations and androgen receptor expression. Androgen activity also impacts on the internal and external genitalia. In target cells, androgens signal through a classical and a nonclassical pathway. This review addresses the most recent advances in the knowledge of the role of androgen signaling in postnatal male sexual development, with a special emphasis on human puberty.

Pharmacology and perspectives in erectile dysfunction in man

Penile erection is a perfect example of microcirculation modulated by psychological factors and hormonal status. It is the result of a complex neurovascular process that involves the integrative synchronized action of vascular endothelium; smooth muscle; and psychological, neuronal, and hormonal systems. Therefore, the fine coordination of these events is essential to maintain penile flaccidity or allow erection; an alteration of these events leads to erectile dysfunction (ED). ED is defined as the consistent or recurrent inability of a man to attain and/or maintain a penile erection sufficient for sexual activity. A great boost to this research field was given by commercialization of phosphodiesterase-5 (PDE5) inhibitors. Indeed, following the discovery of sildenafil, research on the mechanisms underlying penile erection has had an enormous boost, and many preclinical and clinical papers have been published in the last 10 years. This review is structured to provide an overview of the mediators and peripheral mechanism(s) involved in penile function in men, the drugs used in therapy, and the future prospective in the management of ED. Indeed, 30% of patients affected by ED are classified as "nonresponders," and there is still an unmet need for therapeutic alternatives. A flowchart suggesting the guidelines for ED evaluation and the ED pharmacological treatment is also provided.

Expression of androgen, estrogen, and progesterone hormone receptors in the penile tissues of children with different types of hypospadias

OBJECTIVE:

Androgen (AR), Estrogen (ER) and Progesterone (PR) hormones play an important role in the prenatal and postnatal development of urogenital tract and especially the penis. The expressions of AR, ER and PR receptors in penile tissues in children with hypospadiases had also been shown previously. In this leading study, to demonstrate of the sex hormone receptor expression in cases with different types of hypospadias were aimed.

METHODS:

This study was designed in children operated due to hypospadiases without DSD. Biopsy samples of 3 mm’s were obtained from three different sytes as the lateral parameatal tissue and the anterior corner of the prepuce, and inner layer of posterior prepuce. The presence of AR, ER and PR receptors was investigated immunehistochemically.

RESULTS:

Mean age was 5.4 years in 18 children with hypospadiases; in totally 33 specimens were taken in 5 subcoronal as 5 specimens, and 7 penile as 15 specimens, and 6 penoscrotal as 13 specimens. According to sytes of samples; 13 samples were from lateral para-meatal tissues, and 13 were from anterior corners of prepuces, and 7 were from inner layers of posterior prepuces. In regard to receptor expression; ER and AR receptors were positive in 29 (87.8%) and 12 (36.4%) respectively; PR receptors were negative.

CONCLUSION:

This study emphasized the dominant expression of estrogen receptors in penile tissues of children with hypospadias. Although there was not a manifest correlation of androgen receptors absence in regard to the severity of hypospadias patients, there was a marked estrogen receptors presence in penile tissues. These findings suggest that the disrupted androgen and estrogen receptor interaction and/or balance could play a role during the development of external genitalia in hypospadias patients. Progesterone receptor was not present and therefore the active role in the postnatal development of hypospadias is still debatable.

Genomic and non-genomic effects of androgens in the cardiovascular system: clinical implications

The principle steroidal androgens are testosterone and its metabolite 5α-dihydrotestosterone (DHT), which is converted from testosterone by the enzyme 5α-reductase. Through the classic pathway with androgens crossing the plasma membrane and binding to the androgen receptor (AR) or via mechanisms independent of the ligand-dependent transactivation function of nuclear receptors, testosterone induces genomic and non-genomic effects respectively. AR is widely distributed in several tissues, including vascular endothelial and smooth muscle cells. Androgens are essential for many developmental and physiological processes, especially in male reproductive tissues. It is now clear that androgens have multiple actions besides sex differentiation and sexual maturation and that many physiological systems are influenced by androgens, including regulation of cardiovascular function [nitric oxide (NO) release, Ca²⁺ mobilization, vascular apoptosis, hypertrophy, calcification, senescence and reactive oxygen species (ROS) generation]. This review focuses on evidence indicating that interplay between genomic and non-genomic actions of testosterone may influence cardiovascular function.

Persistent erectile dysfunction in men exposed to the 5α-reductase inhibitors, finasteride, or dutasteride

Importance

Case reports describe persistent erectile dysfunction (PED) associated with exposure to 5α-reductase inhibitors (5α-RIs). Clinical trial reports and the manufacturers’ full prescribing information (FPI) for finasteride and dutasteride state that risk of sexual adverse effects is not increased by longer duration of 5α-RI exposure and that sexual adverse effects of 5α-RIs resolve in men who discontinue exposure.

Objective

Our chief objective was to assess whether longer duration of 5α-RI exposure increases risk of PED, independent of age and other known risk factors. Men with shorter 5α-RI exposure served as a comparison control group for those with longer exposure.

Design

We used a single-group study design and classification tree analysis (CTA) to model PED (lasting ≥90 days after stopping 5α-RI). Covariates included subject attributes, diseases, and drug exposures associated with sexual dysfunction.

Setting

Our data source was the electronic medical record data repository for Northwestern Medicine.

Subjects

The analysis cohorts comprised all men exposed to finasteride or dutasteride or combination products containing one of these drugs, and the subgroup of men 16–42 years old and exposed to finasteride ≤1.25 mg/day.

Main outcome and measures

Our main outcome measure was diagnosis of PED beginning after first 5α-RI exposure, continuing for at least 90 days after stopping 5α-RI, and with contemporaneous treatment with a phosphodiesterase-5 inhibitor (PDE₅I). Other outcome measures were erectile dysfunction (ED) and low libido. PED was determined by manual review of medical narratives for all subjects with ED. Risk of an adverse effect was expressed as number needed to harm (NNH).

Results

Among men with 5α-RI exposure, 167 of 11,909 (1.4%) developed PED (persistence median 1,348 days after stopping 5α-RI, interquartile range (IQR) 631.5–2320.5 days); the multivariable model predicting PED had four variables: prostate disease, duration of 5α-RI exposure, age, and nonsteroidal anti-inflammatory drug (NSAID) use. Of 530 men with new ED, 167 (31.5%) had new PED. Men without prostate disease who combined NSAID use with >208.5 days of 5α-RI exposure had 4.8-fold higher risk of PED than men with shorter exposure (NNH 59.8, all p < 0.002). Among men 16–42 years old and exposed to finasteride ≤1.25 mg/day, 34 of 4,284 (0.8%) developed PED (persistence median 1,534 days, IQR 651–2,351 days); the multivariable model predicting PED had one variable: duration of 5α-RI exposure. Of 103 young men with new ED, 34 (33%) had new PED. Young men with >205 days of finasteride exposure had 4.9-fold higher risk of PED (NNH 108.2, p < 0.004) than men with shorter exposure.

Conclusion and relevance

Risk of PED was higher in men with longer exposure to 5α-RIs. Among young men, longer exposure to finasteride posed a greater risk of PED than all other assessed risk factors.

Androgens modulate male-derived endothelial cell homeostasis using androgen receptor-dependent and receptor-independent mechanisms

BACKGROUND

Sex-related differences in the role of androgen have been reported in cardiovascular diseases and angiogenesis. Moreover, androgen receptor (AR) has been causally involved in the homeostasis of human prostate endothelial cells. However, levels of expression, functionality and biological role of AR in male- and female-derived human endothelial cells (ECs) remain poorly characterized. The objectives of this work were (1) to characterize the functional expression of AR in male- and female-derived human umbilical vein endothelial cell (HUVEC), and (2) to specifically analyze the biological effects of DHT, and the role of AR on these effects, in male-derived HUVECs (mHUVECs).

RESULTS

Immunohistochemical analyses of tissue microarrays from benign human tissues confirmed expression of AR in ECs from several androgen-regulated and non-androgen-regulated human organs. Functional expression of AR was validated in vitro in male- and female-derived HUVECs using quantitative RT-PCR, immunoblotting and AR-mediated transcriptional activity assays. Our results indicated that functional expression of AR in male- and female-derived HUVECs was heterogeneous, but not sex dependent. In parallel, we analyzed in depth the biological effects of DHT, and the role of AR on these effects, on proliferation, survival and tube formation capacity in mHUVECs. Our results indicated that DHT did not affect mHUVEC survival; however, DHT stimulated mHUVEC proliferation and suppressed mHUVEC tube formation capacity. While the effect of DHT on proliferation was mediated through AR, the effect of DHT on tube formation did not depend on the presence of a functional AR, but rather depended on the ability of mHUVECs to further metabolize DHT.

CONCLUSIONS

(1) Heterogeneous expression of AR in male- and female-derived HUVEC could define the presence of functionally different subpopulations of ECs that may be affected differentially by androgens, which could explain, at least in part, the pleiotropic effects of androgen on vascular biology, and (2) DHT, and metabolites of DHT, generally thought to represent progressively more hydrophilic products along the path to elimination, may have differential roles in modulating the biology of human ECs through AR-dependent and AR-independent mechanisms, respectively.

Molecular mechanisms associated with diabetic endothelial-erectile dysfunction

Erectile dysfunction (ED) is a common complication of diabetes, affecting up to 75% of all diabetic men. Although the aetiology of diabetic ED is multifactorial, endothelial dysfunction is recognized as a mainstay in the pathophysiology of the disease. Endothelial dysfunction is induced by the detrimental actions of high glucose levels and increased oxidative stress on endothelial cells that make up the vascular lining. Besides directly injuring the endothelium, diabetes might also hamper vascular repair mechanisms of angiogenesis and vasculogenesis. These states exacerbate and maintain endothelial dysfunction, impairing vasorelaxation events and cavernosal blood perfusion, which are crucial for normal erectile function.

Hydrogen Sulfide and Urogenital Tract

In this chapter the role played by H2S in the physiopathology of urogenital tract revising animal and human data available in the current relevant literature is discussed. H2S pathway has been demonstrated to be involved in the mechanism underlying penile erection in human and experimental animal. Both cystathionine-β synthase (CBS) and cystathionine-γ lyase (CSE) are expressed in the human corpus cavernosum and exogenous H2S relaxes isolated human corpus cavernosum strips in an endothelium-independent manner. Hydrogen sulfide pathway also accounts for the direct vasodilatory effect operated by testosterone on isolated vessels. Convincing evidence suggests that H2S can influence the cGMP pathway by inhibiting the phosphodiesterase 5 (PDE-5) activity. All these findings taken together suggest an important role for the H2S pathway in human corpus cavernosum homeostasis. However, H2S effect is not confined to human corpus cavernosum but also plays an important role in human bladder. Human bladder expresses mainly CBS and generates in vitro detectable amount of H2S. In addition the bladder relaxant effect of the PDE-5 inhibitor sildenafil involves H2S as mediator. In conclusion the H2S pathway is not only involved in penile erection but also plays a role in bladder homeostasis. In addition the finding that it involved in the mechanism of action of PDE-5 inhibitors strongly suggests that modulation of this pathway can represent a therapeutic target for the treatment of erectile dysfunction and bladder diseases.

Androgens modulate endothelial function and endothelial progenitor cells in erectile physiology

The incidence of erectile dysfunction (ED) increases with age and cardiovascular disease risk factors, such as hypertension, hyperlipidemia, insulin resistance, obesity, and diabetes. These risk factors are thought to contribute to endothelial dysfunction and atherosclerosis, thus contributing to the pathophysiology of ED. The role of the endothelium in regulating erectile physiology is well established. However, the role of androgens in modulating endothelial function and endothelial repair mechanisms subsequent to vascular injury in erectile tissue remains a subject of intensive research. The clinical and preclinical evidence discussed in this review suggests that androgens regulate endothelial function and also play an important role in the development and maturation of endothelial progenitor cells (EPCs), which are thought to play a critical role in repair of endothelial injury in vascular beds. In this review, we discuss the data available on the effects of androgens on endothelial function and EPCs in the repair of vascular injury. Indeed, more research is needed to fully understand the molecular and cellular basis of androgen action in regulating the development, differentiation, maturation, migration, and homing of EPCs to the site of injury. A better understanding of these processes will be critical to the development of new therapeutic approaches to the treatment of vascular ED.

Role of androgen and vitamin D receptors in endothelial cells from benign and malignant human prostate

Forty years ago, Judah Folkman (Folkman. N Engl J Med 285: 1182-1186, 1971) proposed that tumor growth might be controlled by limiting formation of new blood vessels (angiogenesis) needed to supply a growing tumor with oxygen and nutrients. To this end, numerous "antiangiogenic" agents have been developed and tested for therapeutic efficacy in cancer patients, including prostate cancer (CaP) patients, with limited success. Despite the lack of clinical efficacy of lead anti-angiogenic therapeutics in CaP patients, recent published evidence continues to support the idea that prostate tumor vasculature provides a reasonable target for development of new therapeutics. Particularly relevant to antiangiogenic therapies targeted to the prostate is the observation that specific hormones can affect the survival and vascular function of prostate endothelial cells within normal and malignant prostate tissues. Here, we review the evidence demonstrating that both androgen(s) and vitamin D significantly impact the growth and survival of endothelial cells residing within prostate cancer and that systemic changes in circulating androgen or vitamin D drastically affect blood flow and vascularity of prostate tissue. Furthermore, recent evidence will be discussed about the expression of the receptors for both androgen and vitamin D in prostate endothelial cells that argues for direct effects of these hormone-activated receptors on the biology of endothelial cells. Based on this literature, we propose that prostate tumor vasculature represents an unexplored target for modulation of tumor growth. A better understanding of androgen and vitamin D effects on prostate endothelial cells will support development of more effective angiogenesis-targeting therapeutics for CaP patients.

Controversies on clitoroplasty

A review of the literature regarding the current state of knowledge of the anatomic and physiologic features of the female clitoris was conducted. Based on this evaluation, operations on the clitoris were reviewed. The anatomic and physiologic reconstruction problems of surgical techniques for female pseudohermaphroditism that have previously been reported were reviewed. The author suggests that clitoroplasty is essential for patients with ambiguous genitalia, but the decision regarding the correct procedure, taking into account anatomic and physiologic success, can be controversial. This may be because of unclear anatomic and physiologic definitions, even for healthy people. As a temporary solution, more conservative procedures for maximally effective treatment are suggested.

Morphology of the external genitalia of the adult male and female mice as an endpoint of sex differentiation

Adult external genitalia (ExG) are the endpoints of normal sex differentiation. Detailed morphometric analysis and comparison of adult mouse ExG has revealed 10 homologous features distinguishing the penis and clitoris that define masculine vs. feminine sex differentiation. These features have enabled the construction of a simple metric to evaluate various intersex conditions in mutant or hormonally manipulated mice. This review focuses on the morphology of the adult mouse penis and clitoris through detailed analysis of histologic sections, scanning electron microscopy, and three-dimensional reconstruction. We also present previous results from evaluation of "non-traditional" mammals, such as the spotted hyena and wallaby to demonstrate the complex process of sex differentiation that involves not only androgen-dependent processes, but also estrogen-dependent and hormone-independent mechanisms.

Testosterone, endothelial health, and erectile function

Experimental and clinical studies have reported that testosterone has a critical role in the maintenance of homeostatic and morphologic corpus cavernosum components, essential for normal erectile physiology. Although the exact mechanisms mediated by testosterone in erectile function are still under investigation, recent research has suggested an important role in the regulation of endothelial cell (EC) biological functions. Besides stimulating the production of EC mediators, testosterone is also thought to promote the vasculogenic reendothelialization process, mediated by bone marrow-derived endothelial progenitor cells. Additionally, testosterone seems to modulate other erectile tissue components, including trabecular smooth muscle cells, nerve fibers, and tunica albuginea structure, all essential for the erectile process. This paper summarizes current data regarding testosterone-induced cellular and molecular mechanisms that regulate penile tissue components, focusing particularly on the role of testosterone in endothelial health and erectile function.

Androgen deprivation induces rapid involution and recovery of human prostate vasculature

The response of the prostate tissue microenvironment to androgen deprivation (AD) represents a critical component in the treatment of benign prostatic hyperplasia and prostate cancer (CaP). Primary xenografts of human benign and CaP tissue transplanted to immunocompromized SCID mice were used to characterize the response of the prostate vasculature during the initial 14 days of AD. Microvessel density and vascular lumen diameter in the prostate xenografts decreased rapidly after AD, reached a nadir on days 2-4, and recovered between days 4 and 14. The number of apoptotic endothelial cells peaked on day 2 after AD and decreased to precastration levels over days 4-7. Leakage of vascular contents in the interstitial space was apparent between days 1 and 3 after AD; however, the vascular permeability barrier reestablished between days 7 and 14. Expression of vascular endothelial growth factor (VEGF)-A, VEGF receptor-2, and basic fibroblast growth factor protein increased in endothelial cells between days 2 and 4 after AD, which preceded vascular recovery and appeared to be a direct and specific response of the endothelial cells to AD. Lack of comparable upregulation of these genes in primary cultures of human prostate endothelial cells in response to AD suggests a role for paracrine signaling mediated through stromal or epithelial cells. VEGF-A expression by prostate endothelial cells appears to represent a key facilitator of the vascular rebound in human prostate tissue induced by removal of circulating testicular androgens.

Estrogen stimulates female biliary epithelial cell interleukin-6 expression in mice and humans

Females are more susceptible than males to several biliary tract diseases. Interleukin-6 (IL-6) is critical to triggering autoimmune reactions and contributes substantially to biliary epithelial cell (BEC) barrier function and wound repair, and estrogen differentially regulates IL-6 expression in various cell types. We hypothesized that estrogen might stimulate BEC IL-6 production. Exposure to physiologic levels of estradiol, in vitro, increased female mouse BEC (mBEC) IL-6 messenger RNA (mRNA) and protein expression, but either inhibited or had no effect on male mBECs. Female mBECs expressed higher concentrations of estrogen receptor-alpha (ERalpha) mRNA and protein and were also more dependent on estradiol for survival, in vitro. In vivo, elevated estrogen during estrous cycling in mice, and estrogen treatment of mice harboring an ERalpha(+) human cholangiocarcinoma resulted in increased BEC IL-6 mRNA and tumor viability, respectively. Both responses could be blocked by an ERalpha antagonist. Human cholangiocarcinoma cell lines differentially expressing ERalpha were treated with specific ERalpha and ERbeta agonists/antagonists to further test the relationship between estrogen stimulation, ERalpha expression, and IL-6 production. Results show that ERalpha, and not the underlying BEC sex, was responsible for estrogen-induced IL-6 production. Estrogen-induced proliferation of ERalpha-expressing cholangiocarcinoma was blocked by anti-IL-6 antibodies, indicating that at least some of the estrogen-trophic effects are mediated via IL-6. Finally, an association between ERalpha, IL-6, and phosphorylated signal transducer and activator of transcription 3 (pSTAT3) signaling was shown in female-predominant polycystic livers using immunohistochemical analyses, including multiplex quantum dot labeling.

CONCLUSION

Estrogens stimulate IL-6 production in non-neoplastic female BECs and in neoplastic BECs expressing ERalpha. An association between these signaling pathways was demonstrated for female-predominant polycystic livers and might also influence autoimmune hepatitis, primary biliary cirrhosis, and cholangiocarcinogenesis.

Normal morphology and hormone receptor expression in the male California sea lion (Zalophus californianus) genital tract

Histomorphology and estrogen alpha (ER alpha), and progesterone receptor (PR) expression were evaluated in free-ranging stranded male California sea lions (Zalophus californianus). Hormone receptor expression was evaluated using an immunohistochemical technique with monoclonal antibodies. Estrogen and PRs were identified in the efferent ductules, prostate gland, corpus cavernosa, corpus spongiosium, penile urethra, and in the epithelium and stroma of both the penis and prepuce. In some tissues, ER alpha expression was more intense in the stroma, emphasizing the importance of the stroma in hormone-mediated growth and differentiation of reproductive organs. To our knowledge, this is the first study to localize ER alpha and PR to the epithelium of the glans penis. The results of this investigation add to the general knowledge of male California sea lion reproduction and suggest that estrogens could have a role in the function of the male reproductive tract.

The ontogenetic expression pattern of type 5 phosphodiesterase correlates with androgen receptor expression in rat corpora cavernosa

INTRODUCTION

The mechanisms controlling erection in animals and in humans are mainly age-dependent. However, the ontogenesis of the biochemical machinery of erection is largely unknown.

AIM

The aim of this article was to study the expression pattern of androgen receptor (AR) and the major cyclic guanosine monophosphate-hydrolyzing enzyme present in the corpora cavernosa, type 5 phosphodiesterase (PDE5), in the rat penis during development.

METHODS

AR and PDE5 expression was tested on ribonucleic acids (RNAs) and proteins extracted from the whole penis or from primary cultures of smooth muscle cells obtained from the corpora cavernosa of 3- (rCC3), 20- (rCC20), and 60- (rCC60) day-old rats. Rat corpus cavernosum cells were characterized by immunocytochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR).

MAIN OUTCOME MEASURES

Expression of PDE5 and AR messenger RNA (mRNA) and protein have been measured by RT-PCR and Western blot, respectively.

RESULTS

A significant increase in PDE5 mRNA expression was observed with RT-PCR from prepuberty to adulthood (0.5 +/- 0.06 vs. 1.6 +/- 0.046 arbitrary units [a.u.]P = 0.049). This age-dependent increase was mirrored by the increase in PDE5 protein expression found when comparing neonatal to adult corpus cavernosum smooth muscle cells (1.5 +/- 0.26 vs. 4.9 +/- 0.59 a.u. P = 0.0038) and the further 1.6-fold increase from rCC20 to rCC60 (4.9 +/- 0.59 vs. 8.0 +/- 0.8 a.u. P = 0.0024). This is the first demonstration of the ontogenetic profile of PDE5 expression in corpus cavernosum smooth muscle. As it has been demonstrated that androgens control PDE5 expression and that PDE5 inhibitors need an optimal androgenic milieu to act perfectly on erection, the expression of AR protein in rat corpus cavernosum cells was then tested by Western blot. A 7.0-fold increase was observed in primary cultured cells from 3 to 60 days old (1.4 +/- 0.38 vs. 9.8 +/- 1.3 a.u. P = 0.0052).

CONCLUSION

The increase in ARs during rat penile development parallels that of PDE5 RNA and protein, thus suggesting a positive effect of androgens on PDE5 expression.

Lower urinary tract symptoms and its potential relation with late-onset hypogonadism

The study of the health status of the aging male takes presently a more integrative approach and it appears that ailments typical of male aging, such as lower urinary tract symptoms (LUTS), (visceral) obesity, metabolic syndrome and erectile failure are significantly interrelated. A common denominator of the above ailments is lower-than-normal testosterone levels occurring in a significant proportion of elderly men. This review addresses the potential connections between LUTS and late-onset hypogonadism. In animal studies there appear to be androgen and estrogen receptors in the urothelium and smooth muscle cells of the urethra and bladder of the rat and rabbit, as well as in the neurons in the autonomic ganglia of the prostatic plexus of the male rat. Upon castration electrically evoked relaxations of the smooth muscle of the prostatic urethra were decreased. There is a Rho-kinase activation/endothelin pathway; possibly involved in the increased smooth muscle activity found in both LUTS/benign prostate hyperplasia. Nitric oxide (NO) appears to have a smooth muscle relaxing effect in the urogenital organs. Studies in humans have convincingly shown that phosphodiestererase inhibitors have a beneficial effect on LUTS. More intervention studies should be undertaken to test the clinical validity of the theoretically plausible interrelationship between LUTS and late-onset hypogonadism.

Androgen receptor is causally involved in the homeostasis of the human prostate endothelial cell

Androgen deprivation causes a reduction of blood flow in the prostate gland that precedes temporally apoptosis of the epithelium. The acute response of prostate endothelial cells to androgen deprivation suggested they represent a primary target for androgen. However, rat prostate endothelial cells were reported not to express androgen receptor (AR), and the role of the androgen axis in human prostate endothelial cell (HPEC) homeostasis was poorly characterized. In this study AR expression was detected in HPEC in vivo in clinical specimens of benign prostate and prostate cancer, and AR function as a transcription factor was demonstrated in HPEC in primary xenografts of human benign prostate tissue transplanted into severe combined immunodeficient mice by iv administration of adenoviral mouse mammary tumor virus-driven luciferase expression vector. AR expression and functionality were maintained in vitro in primary cultures of HPEC that coexpressed CD31, CD34, von Willebrand factor, intercellular adhesion molecule, vascular endothelial growth factor receptor 1, and vascular endothelial growth factor receptor 2 but did not express prostate-specific antigen. AR expression in primary cultures of HPEC isolated from surgical specimens of benign prostate was validated using RT-PCR, cDNA sequencing, immunocytochemistry, and Western blot analyses. Scatchard analyses demonstrated a single ligand-binding site for R1881 in primary cultures of HPEC, with dissociation constant of 0.25 nm, and AR-mediated transcriptional activity was demonstrated using adenoviral mouse mammary tumor virus-driven luciferase reporters. Dihydrotestosterone increased proliferation in primary cultures of HPEC in a dose-dependent manner without modulating endothelial tube formation in Matrigel (BD Biosciences, Bedford, MA). Therefore, HPECs express functional AR, and androgen plays a direct role in modulating HPEC biology.

Estrogen receptor alpha mediates estrogen-inducible abnormalities in the developing penis

Previously, we reported an association between estrogen receptor-alpha (ERalpha) upregulation and detrimental effects of neonatal diethylstilbestrol (DES) exposure in the rat penis. The objective of this study was to employ the ERalpha knockout (ERalphaKO) mouse model to test the hypothesis that ERalpha mediates DES effects in the developing penis. ERalphaKO and wild-type C57BL/6 mice received oil or DES at a dose of 0.2 microg/pup per day (0.1 mg/kg) on alternate days from postnatal days 2 to 12. Fertility was tested at 80-240 days of age and tissues were examined at 96-255 days of age. DES caused malformation of the os penis, significant reductions in penile length, diameter, and weight, accumulation of fat cells in the corpora cavernosa penis, and significant reductions in weight of the bulbospongiosus and levator ani muscles in wild-type mice. Conversely, ERalphaKO mice treated with DES developed none of the above abnormalities. While nine out of ten male mice sired pups in the wild-type/control group, none did in the wild-type/DES group. ERalphaKO mice, despite normal penile development, are inherently infertile. Both plasma and intratesticular testosterone levels were unaltered in the DES-treated wild-type or DES-treated ERalphaKO mice when compared with controls, although testosterone concentration was much higher in the ERalphaKO mice. Hence, the resistance of ERalphaKO mice to developing penile abnormalities provides unequivocal evidence of an obligatory role for ERalpha in mediating the harmful effects of neonatal DES exposure in the developing penis.

Role of estrogen in induction of penile dysmorphogenesis: a review

In this review, we report permanent dysmorphogenesis of the penis and loss of fertility in adult rats treated neonatally with estrogen. Specifically, we report replacement of smooth muscle cells and cavernous spaces by fat cells in the corpus cavernosum penis, but not in the adjoining corpus spongiosum. Induction of these novel, region-specific phenotypes is dose-dependent, requires a critical window of exposure and associated with decreased testosterone and up-regulation of estrogen receptor α (ERα). The resistance of ERα knockout mice to develop these abnormalities implies an unequivocal role for ERα in mediating maldevelopment of the penis. Additionally, the prevention of estrogen-inducible penile abnormalities by ER antagonist ICI 182 780 implies that a functional ER-mediated pathway is essential for inducing penile abnormalities. Likewise, the ability of testosterone or dihydrotestosterone to negate these abnormalities suggests a role for an androgen receptor (AR)-mediated pathway. Taken together, these observations led us to hypothesize that neonatal estrogen exposure, via an ER-mediated pathway (direct action) or an AR-mediated pathway (indirect action through decreased testosterone) or both pathways, up-regulates ERα expression in stromal cells of the penis, which are then reprogrammed such that their differentiation into smooth muscle cells is inhibited and their differentiation into adipocytes is stimulated.

Expression of estrogen and androgen receptors in children with hypospadias: preliminary report

This investigation was conducted to evaluate the presence of estrogen and androgen receptors in penile tissues of patients with hypospadias. The biopsy specimens from prepuce, glans, and urethral plate were sampled during the hypospadias surgery in five patients and were analyzed immunohistochemically. Twelve specimens were investigated for the presence of estrogen or androgen receptors (n: 24); the result was negative in 9 (37%) and positive in 15 (63%). Estrogen receptors were present in 10 specimens (42%) (prepuce: 5, glans: 3, and urethral plate: 2). Androgen receptors were present in 5 specimens (21%) (prepuce: 3, glans: 1, and urethral plate: 1). There was expression of both estrogen and androgen receptors in 5 specimens and only estrogen receptors in the remaining 5. Dominant expression of estrogen receptors in penile tissues of children with hypospadias may be the postnatal finding of disrupted estrogen and androgen receptor interaction during the intrauterine development of external genitalia.

Significance of hypogonadism in erectile dysfunction

To review the role and significance of hypogonadism, defined as a low testosterone (T) level, in erectile dysfunction (ED). Review of literature. Serum T is below 3 ng/ml in 12% of ED patients, including 4% before and 15% after the age of 50. Replacement studies in men with severe hypogonadism demonstrate that sexual desire and arousal, as well as the frequency of sexual activity and spontaneous erections are clearly T-dependant. Psychic erections are partly T-dependant. The effects of T upon sexual function are dose-dependant up to a threshold level that is consistent within an individual, but markedly variable between individuals, ranging from 2 to 4.5 ng/ml. More evidence is required to confirm a significant impact of T on the intrapenile vascular mechanisms of erections in men as it is the case in animals. No convincing association of T with ED has been found in epidemiological studies. As concerns clinical experience, although a meta-analysis of the randomized controlled trials established that T therapy consistently restores erectile function in young hypogonadal patients with T below 3.46 ng/ml, the effects of this treatment have been mostly disappointing when used alone in older patients consulting for ED who are subsequently diagnosed to have hypogonadism following routine T measurement. These poor results may probably be explained by the high prevalence of co-morbidities, and by the fact that ED itself may induce hypogonadism. Combination therapy with T and PDE5 inhibitor (PDE5I) may be effective in the hypogonadal ED patients when T therapy alone fails. However, more evidence is required to confirm the hypothesis that a minimum level of T is required for a complete effect of PDE5I in certain men, since a PDE5I was able to restore complete erections in severely hypogonadal men. Though a low T level is not always the only cause of ED in hypogonadal ED patients, there are important benefits in screening for hypogonadism in ED. A low T level justifies a 3 month trial of T therapy, before combining a PDE5I if T therapy alone fails.

Aging and Orchidectomy Modulate Expression of VEGF Receptors (Flt-1 and Flk-1) on Corpus Cavernosum of the Rat

Aging and hypogonadic states are known risk factors for erectile dysfunction (ED), contributing together to vascular damage of penile tissue. In the present study, VEGF-specific membrane receptor (VEGFR-1/Flt-1 and VEGFR-2/Flk-1) expression was studied by confocal immunofluorescence in the corpus cavernosum of control rats, rats aged 12 and 18 months, and orchidectomized Wistar rats (90 days of bilateral orchidectomy). Immunocytochemical results demonstrated VEGFR-2 expression restricted to the endothelium in both control and orchidectomized rats. Aged animals (12 and 18 months) presented enlarged vessels with intense VEGFR-2 endothelial staining. On the other hand, VEGFR-1 was demonstrated in smooth muscle fibers, particularly in those that surround vessel endothelium, the endothelial expression being very low in control and orchidectomized rats. However, in the aged rats, a shift resulting in a VEGFR-1 and VEGFR-2 co-localization in the endothelial cell was observed. The findings suggest an upregulation of VEGFR-1 in the corpora cavernosa during aging in the rat, which is evident from an increased expression by endothelial cells.

Connexin43: emerging role in erectile function

Connexins, that have their main function as part of gap junction channels, are proteins expressed in a large number of tissues such as endocrine, nervous, vascular, and muscular tissues. Gap junctions are implicated in tissue homeostasis and control of cell proliferation and differentiation. Interestingly, mutations of connexin genes have been reported in several human diseases (peripheral neuropathies, cardiovascular and dermatological diseases, hereditary cataract, and deafness) and altered expression of connexins have been associated with tumoral progression. Today, several lines of study argue for a critical role of gap junctions in corporal smooth muscle relaxation and erectile response. The present review highlights the emerging role of connexin43, one of these membranous proteins, in the physiology and physiopathology of human erectile function and its possible medical application.

alpha1-Adrenoceptor subtypes in isolated corporal tissue from patients undergoing gender re-assignment

OBJECTIVE

To investigate the pharmacology and functionality of alpha(1)-adrenoceptors in human corpus cavernosum, and to determine the predominant subtype.

MATERIALS AND METHODS

Cavernosal tissue specimens were obtained from the penises of 22 men (mean age 37.4 years) removed during gender re-assignment surgery. The men had been maintained on long-term oestrogen therapy before surgery, to aid the development of secondary feminine characteristics (oestrogen treatments were stopped 6 weeks before surgery). Corpus cavernosum strips were mounted in organ baths perfused with Krebs' solution. A control concentration-response curve (CRC) to phenylephrine (a nonselective alpha(1)-agonist) was obtained. Then the tissues were incubated with the alpha(1A) antagonist, WB4101; the alpha(1B) antagonist, chloroethylclonidine; or the alpha(1D) antagonist BMY 7378 (all at 1 microm) and the CRC to phenylephrine was repeated. The concentration producing a half-maximal response (EC(50)) and pK(B) values (logarithm of the dissociation constant, a measure of affinity) were determined.

RESULTS

WB4101 produced a parallel rightward shift of the CRC to phenylephrine, with a pK(B) of 7.49. BMY 7378 also produced a parallel rightward shift of the CRC to phenylephrine with a pK(B) of 6.45. Chloroethylclonidine had a similar effect on the phenylephrine CRC, with a pK(B) of 5.90.

CONCLUSION

Alpha(1)-adrenoceptors in human cavernosal tissue have a relatively low affinity for BMY 7378 and chloroethylclonidine, but are more sensitive to WB4101. This confirms that the predominant alpha(1)-adrenoceptor subtype in human corpus cavernosum is the alpha(1A) subtype and this might help in developing more selective antagonists and agonists for managing erectile dysfunction and priapism.

Recent insights into androgen action on the anatomical and physiological substrate of penile erection

Erectile response is centrally and peripherally regulated by androgens. The original insights into the mechanisms of action of androgens were that androgens particularly exert effects on libido and that erections in response to erotic stimuli were relatively androgen-independent. It was shown that sexual functions in men required androgen levels at the low end of reference values of testosterone. So it seemed that testosterone was not useful treatment for men with erectile difficulties, particularly following the advent of the phosphodiesterase type 5 (PDE5) inhibitors. However, approximately 50% of those treated with PDE5 inhibitors discontinue their treatment. A number of recent developments shed new light on testosterone treatment of erectile dysfunction (ED) in aging men. (1) A recent insight is that, in contrast to younger men, elderly men might require higher levels of testosterone for normal sexual functioning. (2) Several studies have indicated that PDE5 inhibitors are not always sufficient to restore erectile potency in men, and that testosterone improves the therapeutical response to PDE5 inhibitors considerably. (3) There is growing insight that testosterone has profound effects on tissues of the penis involved in the mechanism of erection and that testosterone deficiency impairs the anatomical and physiological substrate of erectile capacity, reversible upon androgen replacement. The synthesis of PDE5 is upregulated by androgens, and the arterial inflow into the penis is improved by giving androgen. The above invites a re-examination of the merits of giving testosterone to aging men with ED. The beneficial effects of PDE5 inhibitors may only be optimally expressed in a eugonadal environment.

Testosterone and Sleep‐Related Erections: An Overview*

Sleep-related erections have been reported to occur from the intrauterine life to senescence. It has been speculated that the main function of nocturnal erections is to provide adequate engorgement of the corpora cavernosa, which then leads to increased tissue oxygenation. This is in turn to prevent cavernous fibrosis, the histopathological basis for corporeal venoocclusive dysfunction, which probably is the most common cause of organic erectile dysfunction. It has been suggested that sleep-related erections are triggered by the release of nitric oxide by the nitrergic nerve fibers within the cavernous nerves. Androgens regulate this mechanism as well as some other non-nitrergic processes within the corpora cavernosa and within the central nervous system. By contrast, the erectile response to tactile or visual erotic stimuli in wakefulness predominantly involves an androgen-independent system, although it may, at least to a certain degree, also be influenced by androgen-sensitive mechanisms. No doubt, androgens are key players in the physiology of nocturnal erections, and the availability of new, user-friendly testosterone preparations such as transdermal gel and intramuscularly administered testosterone undecanoate stimulates further investigations on this field. The prospect that the quality of sleep may also be improved by an androgen therapy administered to improve sleep-related erections in hypogonadal men needs further basic research and appropriate clinical studies.

Treatment of testicular cancer: Influence on pituitary-gonadal axis and sexual function

OBJECTIVES

To investigate the influence of treatment for testicular cancer on the pituitary-gonadal axis and sexual function in long-time survivors after unilateral orchiectomy.

METHODS

Blood was drawn from patients treated for testicular cancer during routine oncologic follow-up for measurement of luteinizing hormone, follicle-stimulating hormone, sexual hormone-binding globulin, testosterone, and bioavailable testosterone. Sexual function was evaluated using the International Index of Erectile Function 15-item (IIEF-15) questionnaire. Patients were grouped according to treatment: group 1 followed a surveillance strategy, group 2 received two cycles of carboplatin monotherapy, and group 3 underwent cisplatin, etoposide, and bleomycin chemotherapy.

RESULTS

No statistically significant difference was found in the serum hormonal levels among the three groups, and all hormonal levels were within the 95% confidence range, except for follicle-stimulating hormone. The median serum testosterone level was 3.5 ng/mL in group 1, 3.9 ng/mL in group 2, and 4.2 ng/mL in group 3. In group 1, the median IIEF-15 score was 64.0, and the median Erectile Function (EF) domain score was 28. The median scores in groups 2 and 3 were 62.5 for IIEF-15 and 27.5 for EF and 65.0 for IIEF-15 and 30.0 for EF, respectively. No correlation was found between testosterone level and IIEF-15 or EF score.

CONCLUSIONS

None of the treatments investigated had a significant influence on the serum hormonal levels in long-time survivors of testicular cancer. Patients undergoing chemotherapy have no greater risk of developing a hormonal disorder than those following a surveillance strategy, and therapy for testicular cancer is not a risk factor for erectile dysfunction.

Estrogens in males: what have we learned in the last 10 years?

This review focuses on the role of estrogen in men, mainly in male reproduction. The continuing increase in data obtained, and recent discoveries in this area will enable a better understanding of male physiology; these, in turn, will have important clinical implications.

In vitro viability of human cavernosal endothelial and fibroblastic cells after exposure to papaverine/phentolamine and prostaglandin E1

OBJECTIVE

To investigate the influence of commercially available vasoactive drugs on human cavernosal endothelial and fibroblastic cells in vitro, as although corporal fibrosis is a well known side-effect of intracavernosal injection therapy for erectile dysfunction, the possible detrimental effect of these agents on the endothelium lining the cavernosal vascular spaces is uncertain.

MATERIALS AND METHODS

Cultured primary endothelial (13) and fibroblastic cells (12), obtained from potent patients undergoing penile surgery, were exposed to different physiological dilutions of prostaglandin E1 (PGE1), papaverine/phentolamine or the respective triple-mix of these agents for 30 min. Viable cells were counted and cell metabolic activity measured in these cultures 48 h after drug exposure.

RESULTS

There was a significant dose-dependent decrease in the viable cell count after exposure to papaverine-containing formulations, probably because of the low pH of this substance. This cytotoxic effect was more pronounced in endothelial than in fibroblastic cells, and was not apparent in the PGE1 groups. The relative increase in cell metabolic activity in cultures affected by a moderate cytotoxic effect indicated a regenerative process.

CONCLUSION

These comparative results in endothelial and fibroblastic cell cultures suggest that the endothelium rather than the interstitium of the corpus cavernosum is more sensitive to side-effects produced by intracavernosal injection therapy with papaverine. Thus, unfavourable consequences on the function of the endothelial layer might be as important as the risk of interstitial fibrosis. As these effects were not detected for PGE1 this drug should be preferred to papaverine in clinical practice.

Isolation of Primary Endothelial and Stromal Cell Cultures of the Corpus Cavernosum Penis for Basic Research and Tissue Engineering

OBJECTIVES

Primary cell cultures derived from the corpus cavernosum are frequently used as in vitro models to define cellular mechanisms involved in erectile function. However, previous studies often lack detailed isolation protocols or a precise characterisation of the culture composition excluding especially contaminating fibroblasts. This study aimed at critically analysing and reproducing reported isolation methods, as well as establishing new procedures to receive highly pure and morphologically differentiated endothelial, smooth muscle and fibroblastic cells derived from the human penis.

METHODS

We evaluated numerous isolation and enrichment techniques using cavernosal tissue from 57 patients. Assessment factors displayed the purity, cell yield, practicability and reproducibility. The purity in cultured cells was analysed using immunocytochemistry and Western blots.

RESULTS

An enzymatic protocol was established for the isolation and cultivation of cavernosal endothelial cells with an impressive purity of 98.0+/-0.8%. In contrast, already published nearly pure smooth muscle cell cultures were not reproducible in our laboratory. Meaningful evidence for an overwhelming presence of fibroblasts in these widely accepted pure smooth muscle cell cultures is presented.

CONCLUSION

Endothelial cell cultures derived from human corpora cavernosa are reproducible and reliable to serve for cell culture-based investigations of the endothelial dysfunction. The discrepancy in the purity of smooth muscle cell cultures might reflect laboratory and tissue source factors, lacking an exclusion of fibroblasts in other studies or changes in stromal phenotype under culture conditions. Further research is necessary to clarify a possible plasticity between smooth muscle cells and (myo)fibroblasts and assess functional properties.

Cytotoxicity of different intracavernous vasoactive drugs on cultured endothelial cells of human corpus cavernosum penis

OBJECTIVES

To investigate the cytotoxic effect of prostaglandin E(1) (PGE(1)), a standard combination of papaverine/phentolamine, and a triple mixture of these agents on human cavernosal endothelial cells using a cell culture model. The endothelial layer of the corpus cavernosum plays an important role in signal transduction of penile erection and is directly exposed to vasoactive agents after intracavernous injection for erectile dysfunction.

METHODS

Primary endothelial cells were obtained from the corpus cavernosum of 13 potent patients undergoing penile surgery. Cultured cells were exposed for 30 minutes to physiologic dilutions of 20 microg PGE(1), 30 mg papaverine/1 mg phentolamine, or the same dosages of the triple mixture of these agents, each dissolved in 5 to 50 mL sodium chloride. Lactate dehydrogenase release as a cytotoxicity marker was measured 6 hours after drug exposure, and the total cell metabolic activity was quantified after 48 hours with a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS)-based assay. Additionally, the amount of viable cells was identified with a dual fluorescent staining procedure.

RESULTS

The initial release of lactate dehydrogenase was elevated up to 3.2-fold in the concentrated papaverine/phentolamine and triple mixture group compared with PGE(1) and the control. After 48 hours, the papaverine-containing formulations led to a significant dose-dependent decrease in the viable cell count and metabolic activity of the cultures that was not noticed with PGE(1).

CONCLUSIONS

These in vitro data strongly suggest an unfavorable effect of vasoactive agents containing papaverine on cavernosal endothelial cells. Before fibrotic changes of the smooth muscle stroma, the functionally important endothelium of the corpus cavernosum might suffer significantly from intracavernous injection therapy. Therefore, papaverine should no longer be used for this indication.