Is testosterone deficiency a predictive factor for recurrence of urethral stricture?

BACKGROUND

Testosterone plays a vital role in maintaining tissue homeostasis, and testosterone deficiency may potentially influence the likelihood of urethral stricture recurrence.

OBJECTIVES

To evaluate the prognostic value of testosterone levels in the recurrence after direct visual internal urethrotomy in primary short segment bulbar urethral strictures and its clinical reflections.

MATERIALS AND METHODS

A total of 723 patients who underwent direct vision internal urethrotomy between January 2000 and October 2022 were retrospectively analyzed. After implying exclusion criteria, 116 patients with available data were enrolled. Patients were divided into two groups as recurrence and no recurrence. Age, stricture length, etiology, time of recurrence, diagnosis of previous diabetes mellitus, hypertension, smoking, body mass index, and total testosterone levels were recorded. Free testosterone and bioavailable testosterone values were calculated using total testosterone, albumin, and sex hormone binding globulin values. Hypogonadism was considered as a total testosterone level less than 300 ng/dL. Demographic characteristics and total testosterone, free testosterone, and bioavailable testosterone levels were compared between the two groups for statistical significance. The recurrence rates of patients with and without hypogonadism were compared.

RESULTS

Recurrence was observed in 41.4% of the cases (n = 48). There was no statistically significant difference between the groups in terms of age, body mass index values, diabetes mellitus, hypertension, smoking status, presence of hypogonadism, and etiology (p = 0.745, 0.863, 0.621, 0.622, 0.168, 0.051, and 0.232). In terms of total testosterone levels and bioavailable testosterone levels, the recurrence group had significantly lower values (p = 0.018 and 0.04). There was no significant difference between the two groups in terms of stricture length (p = 0.071). Sixteen of 28 patients with hypogonadism had recurrence, whereas 32 of 88 patients without hypogonadism had recurrence (p = 0.051).

DISCUSSION

Testosterone levels have potential to predict recurrence in primary short-segment bulbar urethral strictures. This study represents the inaugural analysis of the impact of testosterone deficiency on recurrence within the cohort of patients with primary short-segment bulbar urethral strictures.

CONCLUSION

Testosterone levels and ratios may serve as predictive factors for identifying recurrent cases in primary short-segment bulbar strictures. For patients at a higher risk of recurrence, urethroplasty may be considered as an initial treatment option, even in cases of primary and short-segment strictures.

Characterization of Vortex Vein Drainage System in Healthy Individuals Imaged by Ultra-Widefield Optical Coherence Tomography Angiography

Purpose

The purpose of this study was to investigate the choroidal characteristics of vortex vein (VV) drainage systems in healthy individuals using ultra-widefield optical coherence tomography angiography.

Methods

The mean choroidal thickness (ChT) and choroidal vascularity index (CVI) of each VV quadrant (24 × 20 mm2 scan mode; superotemporal [ST], superonasal [SN], inferonasal [IN], and inferotemporal [IT] quadrants) were calculated. Furthermore, intervortex venous anastomosis (IVA) was classified into temporal, superior, inferior, and nasal types.

Results

A total of 207 healthy eyes were analyzed to find that the ST quadrant had the thickest choroidal layer and highest CVI (all P < 0.05). Among the four VV drainage quadrants, the mean ChT and CVI decreased in the sequence of ST, SN, IT, and IN (all P < 0.05). Moreover, men had a higher CVI than women in all VV quadrants (all P < 0.05). IVA was observed in all VV quadrants of 91 eyes (43.96%), and in the macular region of 33 eyes (15.94%).

Conclusions

The ST drainage system was identified as the preferred VV drainage route in healthy eyes. Among the four VV drainage quadrants, the drainage system adhered to the ST-SN-IT-IN order of descending perfusion. Furthermore, age- and sex-related differences were noted in the choroidal VV drainage systems of healthy eyes. Additionally, almost half of the healthy eyes had IVA in their choroidal vessel networks.

Translational Relevance

The VV drainage system may be considered a novel imaging biomarker for ocular diseases.

The synthetic cathinones MDPHP and MDPV: Comparison of the acute effects in mice, in silico ADMET profiles and clinical reports

The 3,4-methylenedioxy-alpha-pyrrolidinohexanophenone (MDPHP) is a synthetic cathinone closely related to 3,4-methylenedioxypyrovalerone (MDPV), one of the most common synthetic cathinones present in the "bath salts". MDPHP has recently gained attention due to increasing seizures and involvement in human intoxications which occurred in Europe and Italy in the last years, but currently there is a lack of information about its pharmaco-toxicological effects. With the aim at filling this gap, the present study is endeavoured to (i) evaluate the effects of acute administration of MDPHP (0.01-20 mg/kg; i.p.) on behaviour, cardiorespiratory and cardiovascular parameters in CD-1 male mice, comparing them to those observed after administration of MDPV; (ii) predict the ADMET profile of the two analogues using the Plus ADMET Predictor®; (iii) present clinical data related to MDPHP and MDPV-induced intoxications recorded between 2011 and 2023 by the Pavia Poison Control Centre (PCC) - National Toxicology Information Centre (Istituti Clinici Scientifici Maugeri, IRCCS Pavia, Italy). Our results substantiated that MDPHP and MDPV similarly affect sensorimotor and behavioural responses in mice, importantly increased locomotion and induced aggressive behaviour, and, at higher dosage, increased heart rate and blood pressure. These findings are in line with those observed in humans, revealing severe toxidromes typically characterized by Central Nervous System (CNS) alterations (behavioural/neuropsychiatric symptoms), including psychomotor agitation and aggressiveness, cardiovascular and respiratory disorders (e.g. tachycardia, hypertension, dyspnoea), and other peripheral symptoms (e.g. hyperthermia, acidosis, rhabdomyolysis).

Dihydrotestosterone Augments the Angiogenic and Migratory Potential of Human Endothelial Progenitor Cells by an Androgen Receptor-Dependent Mechanism

Endothelial progenitor cells (EPCs) play a critical role in cardiovascular regeneration. Enhancement of their native properties would be highly beneficial to ensuring the proper functioning of the cardiovascular system. As androgens have a positive effect on the cardiovascular system, we hypothesized that dihydrotestosterone (DHT) could also influence EPC-mediated repair processes. To evaluate this hypothesis, we investigated the effects of DHT on cultured human EPCs' proliferation, viability, morphology, migration, angiogenesis, gene and protein expression, and ability to integrate into cardiac tissue. The results showed that DHT at different concentrations had no cytotoxic effect on EPCs, significantly enhanced the cell proliferation and viability and induces fast, androgen-receptor-dependent formation of capillary-like structures. DHT treatment of EPCs regulated gene expression of androgen receptors and the genes and proteins involved in cell migration and angiogenesis. Importantly, DHT stimulation promoted EPC migration and the cells' ability to adhere and integrate into murine cardiac slices, suggesting it has a role in promoting tissue regeneration. Mass spectrometry analysis further highlighted the impact of DHT on EPCs' functioning. In conclusion, DHT increases the proliferation, migration, and androgen-receptor-dependent angiogenesis of EPCs; enhances the cells' secretion of key factors involved in angiogenesis; and significantly potentiates cellular integration into heart tissue. The data offer support for potential therapeutic applications of DHT in cardiovascular regeneration and repair processes.

Androgen receptor (CAG)n repeat polymorphism contributes to risk of sudden cardiac death originated from coronary artery disease with sex discrepancy

Sudden cardiac death (SCD) is the leading cause of natural death worldwide which is responsible for almost half of all heart disease deaths, making it a substantial public health problem. Previous epidemiological studies from different countries have demonstrated the significant SCD incident difference rate between males and females. Besides environmental and social effects, differential genetic architecture also underlines the SCD incidence discrepancy. To this end, the functional (CAG)_n repeat polymorphism within Androgen Receptor (AR) gene was analyzed to evaluate its associations with SCD originated from coronary artery disease (SCD-CAD) susceptibility in Chinese populations using 182 SCD-CAD cases and 564 healthy controls. At allelic level, the (CAG)₂₆ allele conferred a lower SCD-CAD risk in males (adjusted odds ratio [OR] = 0.428; 95% confidence interval [CI] = 0.254, 0.915; P = 0.023). On the contrary, the (CAG)₂₆ allele was reversely associated with a higher SCD-CAD risk in females (OR = 2.581; 95% CI = 0.944, 7.056; P = 0.057). Further cutoff strategy analysis revealed that those male subjects carrying shorter allele (≤26 repeats) had significantly lower SCD-CAD risk (OR = 0.343; 95% CI = 0.221, 0.531; P = 8.1653e^-7). Additionally, an allele-dependent SCD risk tendency was observed in male subjects. Specifically, compared with males carrying allele longer than 26 repeats, the SCD-CAD risk (OR value) for male subjects carrying shorter alleles (from 25 to 21) gradually increased from 0.437 to 0.533, indicating the (CAG)₂₆ allele of the repeat polymorphism may be the watershed in male SCD etiology. Lastly, the length variations associated with multiple phenotypes were also summarized. Collectively, our results revealed for the first time that the (CAG)_n repeat polymorphism within the AR gene was associated with SCD-CAD risk in Chinese populations with sex discrepancy, proposing a new candidate genetic marker for molecular diagnosis of SCD-CAD. Furthermore, a sex-dependent SCD-CAD risk stratification and prevention approach was encouraged. Further studies with more female samples were warranted to validate our findings.

The Influence of Young Age on Difficulties in the Surgical Resection of Carotid Body Tumors

Simple Summary

The aim of this study was to reveal the factors affecting the complexity and difficulties in performing surgery to resect carotid body tumors (CBTs). We analyzed 20 patients with 21 CBTs. We used the “same day surgery” procedure, including preoperative embolization of the feeding arteries in the morning and resection surgery in the afternoon of the same day. Four patients underwent resection of the carotid artery, followed by reconstruction. These four patients were between 18 to 23 years of age at the time of surgery. The mean blood loss and operative time in these patients differed significantly from those in older patients. These results indicated that young age may influence the difficulties faced in CBT surgery, resulting in an increased risk of carotid artery resection. The results obtained from our study could help surgeons safely and effectively perform resection surgery for CBTs.

Abstract

This study evaluated patient characteristics that affect the complexity and difficulties of performing surgery to resect carotid body tumors (CBTs). We retrospectively reviewed the medical records of 20 patients with 21 CBTs who were enrolled in the study. The median patient age was 46 years and the mean tumor diameter was 37.6 mm. The mean blood loss and operative time were 40.3 mL and 183 min, respectively. Four patients underwent resection of the carotid artery followed by reconstruction. These four patients were between 18 to 23 years of age at the time of surgery. The mean blood loss and operative time in these patients were 166 mL and 394 min, respectively, which differed significantly from those of older patients. Therefore, young age influenced the difficulties faced in surgical resection of CBT, with an increased risk of blood loss and carotid artery resection.

11-Ketotestosterone is a major androgen produced in porcine adrenal glands and testes

Porcine steroid hormone profiles have some unique characteristics. We previously studied human and murine steroidogenesis using steroidogenic cells-derived from mesenchymal stem cells (MSCs). To investigate porcine steroidogenesis, we induced steroidogenic cells from porcine subcutaneous preadipocytes (PSPA cells), which originate from MSCs. Using cAMP, adenovirus-mediated introduction of steroidogenic factor-1 (SF-1)/adrenal 4-binding protein (Ad4BP) induced the differentiation of PSPA cells into sex steroid-producing cells. Introducing SF-1/Ad4BP also induced the aldo-keto reductase 1C1 (AKR1C1) gene. Porcine AKR1C1 had 17β-hydroxysteroid dehydrogenase activity, which converts androstenedione and 11-ketoandrostenedione into testosterone (T) and 11-ketotestosteorne (11KT). Furthermore, differentiated cells expressed hydroxysteroid 11β-dehydrogenase 2 (HSD11B2) and produced 11KT. HSD11B2 was expressed in testicular Leydig cells and the adrenal cortex. 11KT was present in the plasma of both immature male and female pigs, with slightly higher levels in the male pigs. T levels were much higher in the male pigs. It is noteworthy that in the female pigs, the 11KT levels were >10-fold higher than the T levels. However, castration altered the 11KT and T plasma profiles in the male pigs to near those of the females. 11KT induced endothelial nitric oxide synthase (eNOS) in porcine vascular endothelial cells. These results indicate that 11KT is produced in porcine adrenal glands and testes, and may regulate cardiovascular functions through eNOS expression.

Congenital Hypogonadotropic Hypogonadism with Early-Onset Coronary Artery Disease

The patient with congenital hypogonadotropic hypogonadism (HH) shows low serum levels of androgen, which is a group of sex hormones including testosterone, caused by the decreased gonadotropin release in the hypothalamus. Recent reports showed androgens exert protective effects against insulin resistance or atherosclerotic diseases, such as diabetes mellitus or coronary artery disease. However, whether the juvenile hypogonadism affects the diabetes or cardiovascular disease is unclear. We report a case of a middle-aged man with congenital HH who had severe coronary artery disease complicated with metabolic disorders. J. Med. Invest. 68 : 189-191, February, 2021.

Quantitative evaluations of vortex vein ampullae by adjusted 3D reverse projection model of ultra-widefield fundus images

The purpose of this study was to determine the number and location of vortex vein ampullae (VVA) in normal eyes. This was an observational retrospective study. Montage images of one on-axis and two off-axis ultra-widefield images of 74 healthy eyes were enhanced, and reverse projected onto a 3D model eye. The number and distance between the optic disc to each VVA in the four sectors were compared. The significance of correlations between these values and age, sex, visual acuity, refractive error, and axial length was determined. The mean number of VVA was 8.10/eye with 1.84, 2.12, 2.19 and 1.95 in upper lateral, lower lateral, upper nasal, and lower nasal sectors, respectively. The mean number of VVA/eye was significantly greater in men at 8.43 than women at 7.76 (P = 0.025). The mean distance between the optic disc and VVA was 14.15 mm, and it was 14.04, 15.55, 13.29 and 13.66 mm in the upper lateral, lower lateral, upper nasal and lower nasal sectors, respectively (all P < 0.05). The number and location of VVA can be obtained non-invasively, and the number was significantly higher in men than women. This technique can be used to determine whether these values are altered in a retinochoroidal disease.

Androgen receptor DNA methylation is an independent determinant of glucose metabolic disorders in women; testosterone plays a moderating effect

BACKGROUND

We have previously shown that serum testosterone was associated with impaired fasting glucose (IFG) and type 2 diabetes (T2D). Testosterone can be acting through binding the androgen receptor (AR). Therefore, we aimed to explore the independent associations of AR DNA methylation (ARm) with IFG and T2D and the moderation effects of serum testosterone on the associations.

METHODS

A case-control study with 1065 participants including 461 men and 604 women was performed. ARm in peripheral blood sample and serum testosterone were measured using pyrosequeuncing and liquid chromatography-tandem mass, respectively. Multivariable logistic regression was performed to estimate the associations of ARm (including 2 cytosine-phosphoguanine [CpG] islands and average methylation levels) with different glucose status. Serum testosterone was used as a moderator to estimate the moderation effect.

RESULTS

After multivariate adjustment, CpG 1, 2 and CpG average methylation were all significantly associated with IFG (CpG 1: Odds ratio (OR) = 4.80, 95% confidence interval (CI): 2.24-10.27; CpG 2: OR = 4.35, 95% CI: 2.50-7.58; CpG average: OR = 11.73, 95% CI: 5.36-25.67) in women. In addition, testosterone played negative moderation effects in above associations. Moreover, no significant independent associations of methylation levels with T2D was observed both in men and women.

CONCLUSION

Our findings demonstrate that ARm was positively associated with IFG in women and the associations would be weakened by testosterone. The individuals experiencing low testosterone and ARm levels reported a lower state of IFG than those who experienced high levels of testosterone and ARm in women.

Low Serum-Free Testosterone Concentration in Chinese Male Patients with Uncomplicated Acute Type B Aortic Dissection

OBJECTIVE

Although aortic dissection occurs predominantly in men, its association with androgens is unknown. The aim of this study was to evaluate the androgen levels in Chinese male patients with uncomplicated, acute type B aortic dissection.

STUDY DESIGN

Cross-sectional study.

MATERIALS AND METHODS

A total of 192 age-matched male patients with uncomplicated, acute type B aortic dissection or essential hypertension were recruited between 2016 and 2018. The demographic and clinical data were analyzed.

RESULTS

Male patients with uncomplicated, acute type B aortic dissection had lower serum total testosterone and free testosterone than male patients with essential hypertension (7.6 ± 3.7 nmol/L vs. 10.9 ± 3.8 nmol/L, P < 0.001; 36.0 ± 19.8 pmol/L vs. 56.4 ± 19.2 pmol/L, P < 0.001). Lower free testosterone level was significantly associated with uncomplicated, acute type B aortic dissection (univariate odds ratio 0.948, P < 0.001; multivariate odds ratio = 0.966, P = 0.002). No statistical difference was observed for free testosterone between younger patient groups (aged < 51 years; aged 51-60 years) and older patient groups (aged 61-70 years; aged >70 years) with uncomplicated, acute type B aortic dissection (33.7 ± 19.8 pmol/L vs. 38.5 ± 19.8 pmol/L, P = 0.239).

CONCLUSIONS

Lower free testosterone was independently associated with uncomplicated, acute type B aortic dissection in the Chinese male population with hypertension. Additional studies are needed to clarify whether earlier onset in Chinese patients with aortic dissection is associated with androgen deficiency.

Enhanced Skeletal Muscle Oxidative Capacity and Capillary-to-Fiber Ratio Following Moderately Increased Testosterone Exposure in Young Healthy Women

Background: Recently, it was shown that exogenously administered testosterone enhances endurance capacity in women. In this study, our understanding on the effects of exogenous testosterone on key determinants of oxygen transport and utilization in skeletal muscle is expanded.

Methods: In a double-blinded, randomized, placebo-controlled trial, 48 healthy active women were randomized to 10 weeks of daily application of 10 mg of testosterone cream or placebo. Before and after the intervention, VO₂ max, body composition, total hemoglobin (Hb) mass and blood volumes were assessed. Biopsies from the vastus lateralis muscle were obtained before and after the intervention to assess mitochondrial protein abundance, capillary density, capillary-to-fiber (C/F) ratio, and skeletal muscle oxidative capacity.

Results: Maximal oxygen consumption per muscle mass, Hb mass, blood, plasma and red blood cell volumes, capillary density, and the abundance of mitochondrial protein levels (i.e., citrate synthase, complexes I, II, III, IV-subunit 2, IV-subunit 4, and V) were unchanged by the intervention. However, the C/F ratio, specific mitochondrial respiratory flux activating complex I and linked complex I and II, uncoupled respiration and electron transport system capacity, but not leak respiration or fat respiration, were significantly increased following testosterone administration compared to placebo.

Conclusion: This study provides novel insights into physiological actions of increased testosterone exposure on key determinants of oxygen diffusion and utilization in skeletal muscle of women. Our findings show that higher skeletal muscle oxidative capacity coupled to higher C/F ratio could be major contributing factors that improve endurance performance following moderately increased testosterone exposure.

LIN28B regulates androgen receptor in human trophoblast cells through Let-7c

LIN28B is an RNA-binding protein necessary for maintaining pluripotency in stem cells and plays an important role in trophoblast cell differentiation. LIN28B action on target gene function often involves the Let-7 miRNA family. Previous work in cancer cells revealed that LIN28 through Let-7 miRNA regulates expression of androgen receptor (AR). Considering the similarities between cancer and trophoblast cells, we hypothesize that LIN28B also is necessary for the presence of AR in human trophoblast cells. The human first-trimester trophoblast cell line, ACH-3P was used to evaluate the regulation of AR by LIN28B, and a LIN28B knockdown cell line was constructed using lentiviral-based vectors. LIN28B knockdown in ACH-3P cells resulted in significantly decreased levels of AR and increased levels of Let-7 miRNAs. Moreover, treatment of ACH-3P cells with Let-7c mimic, but not Let-7e or Let-7f, resulted in a significant reduction in LIN28B and AR. Finally, forskolin-induced syncytialization and Let-7c treatment both resulted in increased expression of syncytiotrophoblast marker ERVW-1 and a significant decrease in AR in ACH-3P. These data reveal that LIN28B regulates AR levels in trophoblast cells likely through its inhibitory actions on let-7c, which may be necessary for trophoblast cell differentiation into the syncytiotrophoblast.

Role of androgens in cardiovascular pathology

Cardiovascular effects of android hormones in normal and pathological conditions can lead to either positive or negative effects. The reason for this variation is unknown, but may be influenced by gender-specific effects of androids, heterogeneity of the vascular endothelium, differential expression of the androgen receptor in endothelial cells (ECs) and route of androgen administration. Generally, androgenic hormones are beneficial for ECs because these hormones induce nitric oxide production, proliferation, motility, and growth of ECs and inhibit inflammatory activation and induction of procoagulant, and adhesive properties in ECs. This indeed prevents endothelial dysfunction, an essential initial step in the development of vascular pathologies, including atherosclerosis. However, androgens can also activate endothelial production of some vasoconstrictors, which can have detrimental effects on the vascular endothelium. Androgens also activate proliferation, migration, and recruitment of endothelial progenitor cells (EPCs), thereby contributing to vascular repair and restoration of the endothelial layer. In this paper, we consider effects of androgen hormones on EC and EPC function in physiological and pathological conditions.

Role of androgens for urethral homeostasis

Background

We observed that patients with hypogonadism are at higher risk to experience artificial urinary sphincter cuff erosion. Sphincter erosions have been found to be associated with urethral atrophy or compromised urethras subsequent to events limiting its blood supply. We therefore analyzed possible mechanisms how a decrease in testosterone serum levels can result decreased urethral blood flow.

Methods

In a cohort of >1,200 urethroplasties, tissue specimens obtained during surgeries were analyzed for expression of androgen receptor (AR), AR-responsive TIE-2 associated with angiogenesis, and the endothelial cell marker CD31 for determination of vessel counts were analyzed immunohistochemically. A total of 11 patients were included in whom both tissue and serum testosterone levels within 2 years of the urethroplasty was available. Low serum testosterone level defined as <280 ng/dL. Image J software was used to analyze expression profiles.

Results

Mean serum testosterone level was significant lower in hypogonadal patients (179.4 ng/dL) compared to eugonadal patients (375.0 ng/dL, P=0.003). Urethral tissue of hypogonadal patients showed decreased AR expression [1.11% high power field (HPF)] compared to eugonadal patients (1.62%, P=0.016), decreased TIE-2 expression (1.84% HPF vs. 3.08%, P=0.006), and also decreased vessel counts (44.47 vessels/HPF vs. 98.33, P=0.004). There was a direct correlation of AR and TIE-2 expression levels with serum testosterone levels (rho 0.685, P=0.029, and rho 0.773, P=0.005, respectively). Of note, we did not detect a difference in age, prior radiation, coronary artery disease or hypertension among hypo- or eugonadal patient. However, higher body mass index was associated with low serum testosterone levels.

Conclusions

Hypogonadal status is associated with decreased expression of AR and TIE-2 and also reduced vessel count in urethral tissue. We believe that the resulting decreased urethral vascularity subsequent to a hypogonadal state may be an important risk factor for complications of urethral surgery.

Expression profile of the STAND protein Nwd1 in the developing and mature mouse central nervous system

The orchestrated events required during brain development, as well as the maintenance of adult neuronal plasticity, highly depend on the accurate responses of neuronal cells to various cellular stress or environmental stimuli. Recent studies have defined a previously unrecognized, broad class of multidomain proteins, designated as signal transduction ATPases with numerous domains (STAND), which comprises a large number of proteins, including the apoptotic peptidase activating factor 1 (Apaf1) and nucleotide-binding oligomerization domain-like receptors (NLRs), central players in cell death and innate immune responses, respectively. Although the involvement of STANDs in the central nervous system (CNS) has been postulated in terms of neuronal development and function, it remains largely unclear. Here, we identified Nwd1 (NACHT and WD repeat domain-containing protein 1), as a novel STAND protein, expressed in neural stem/progenitor cells (NSPCs). Structurally, Nwd1 was most analogous to the apoptosis regulator Apaf1, also involved in mitosis and axonal outgrowth regulation in the CNS. Using a specific antibody, we show that, during the embryonic and postnatal period, Nwd1 is expressed in nestin-positive NSPCs in vivo and in vitro, while postnatally it is found in terminally differentiated neurons and blood vessels. At the subcellular level, we demonstrate that Nwd1 is preferentially located in the cytosolic compartment of cultured NSPCs, partially overlapping with cytochrome c. These observations imply that Nwd1 might be involved in the neuronal lineage as a new STAND gene, including having a pro-apoptotic or nonapoptotic role, similar to Apaf1.

Testosterone promotes tube formation of endothelial cells isolated from veins via activation of Smad1 protein

Testosterone (T) deficiency is positively correlated with the increased incidence of cardiovascular disease. However, the effects of T on vascular endothelial cells remain obscure. Tube formation capacity is critical for vascular regeneration/repair and Smad1 plays an important role in these events. In this study, we investigated the effects of T on Smad1 activation and tube formation of cultured human umbilical endothelial cells (HUVECs). Our results showed that T rapidly increased endothelial Smad1 phosphorylation. This effect was mimicked by cell-impermeable T-BSA conjugates and was not altered by transcriptional inhibitor actinomycin D or translational inhibitor cycloheximide. T-induced Smad1 phosphorylation was blocked by ERK1/2 and c-Src inhibitors or their specific siRNAs, while it was reinforced by ERK1/2 or c-Src overexpression. Indeed, T rapidly activated ERK1/2 and c-Src signalings and c-Src was confirmed as the upstream of ERK1/2. Moreover, caveolae disruptor methyl-β-cyclodextrin (β-MCD) blocked Smad1 activation induced by T. The association of caveolin-1 with androgen receptor (AR) or c-Src was detected by immunoprecipitation and it was significantly increased by rapid T stimulation. Furthermore, fractional analysis showed that AR and c-Src were expressed in caveolae-enriched membrane fractions. T promoted tube formation of HUVECs, which was blocked by c-Src and ERK1/2 inhibitors or by the knockdown of Smad1. In conclusion, T increased tube formation of endothelial cells isolated from veins by stimulating Smad1 phosphorylation in a nongenomic manner, which was mediated by signals from AR/c-Src located in caveolae to ERK1/2 cascade. These findings may shed new light on the relevance of T to its vascular functions.

Testosterone Prevents Cutaneous Ischemia and Necrosis in Males Through Complementary Estrogenic and Androgenic Actions

OBJECTIVE

Chronic nonhealing wounds are a substantial medical concern and are associated with morbidity and mortality; thus, new treatment strategies are required. The first step toward personalized/precision medicine in this field is probably in taking sex differences into account. Impaired wound healing is augmented by ischemia, and we previously demonstrated that 17β-estradiol exerts a major preventive effect against ischemia-induced skin flap necrosis in female mice. However, the equivalent effects of testosterone in male mice have not yet been reported. We then investigated the role of steroid hormones in male mice using a skin flap ischemia model.

APPROACH AND RESULTS

Castrated male mice developed skin necrosis after ischemia, whereas intact or castrated males treated with testosterone were equally protected. Testosterone can (1) activate the estrogen receptor after its aromatization into 17β-estradiol or (2) be reduced into dihydrotestosterone, a nonaromatizable androgen that activates the androgen receptor. We found that dihydrotestosterone protected castrated wild-type mice by promoting skin revascularization, probably through a direct action on resistance arteries, as evidenced using a complementary model of flow-mediated outward remodeling. 17β-estradiol treatment of castrated male mice also strongly protected them from ischemic necrosis through the activation of estrogen receptor-α by increasing skin revascularization and skin survival. Remarkably, 17β-estradiol improved skin survival with a greater efficiency than dihydrotestosterone.

CONCLUSIONS

Testosterone provides males with a strong protection against cutaneous necrosis and acts through both its estrogenic and androgenic derivatives, which have complementary effects on skin survival and revascularization.

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.