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Recent Issue: ESSM Today # 44

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Mario Lourenco

ERECTILE DYSFUNCTION

Yin GN, Park SH, Ock J, Choi MJ, Limanjaya A, Ghatak K, Song KM, Kwon MH, Kim DK, Gho YS, Suh JK, Ryu JK. Pericyte-Derived Extracellular VesicleMimetic Nanovesicles Restore Erectile Function by Enhancing Neurovascular Regeneration in a Mouse Model of Cavernous Nerve Injury. J Sex Med. 2020 Nov;17(11):2118-2128. doi: 10.1016/j. jsxm.2020.07.083. Epub 2020 Aug 24. PMID: 32855091.

The authors aimed to investigate the potential effect of pericyte-derived nanovesicles (PC-NVs) in neurovascular regeneration in the context of erectile dysfunction. PC-NVs were isolated from mouse cavernous pericytes, and neurovascular regeneration was evaluated in an in vitro study. Twelve-week-old C57BL/6J mice were used to prepare cavernous nerve injury model. In the in vivo studies, PC-NVs successfully improved erectile function in cavernous nerve injury mice (~82% of control values). Immunofluorescence staining showed significant increases in pericytes, endothelial cell, and neuronal contents. In the in vitro studies, PC-NVs significantly increased mouse cavernous endothelial cells tube formation, Schwann cell migration, and dorsal root ganglion and major pelvic ganglion neurite sprouting. Finally, Western blot analysis revealed that PC-NVs upregulated cell survival signaling (Akt and eNOS) and induced the expression of neurotrophic. In conclusion, PC-NVs significantly improved erectile function by enhancing neurovascular regeneration. Local treatment with PC-NVs may represent a promising therapeutic strategy for the treatment of neurovascular diseases.

Bragina ME, Costa-Fraga F, Sturny M, Ebadi B, Ruoccolo RT, Santos RAS, FragaSilva RA, Stergiopulos N. Characterization of the Renin-Angiotensin System in Aged Cavernosal Tissue and its Role in Penile Fibrosis. J Sex Med. 2020 Nov;17(11):2129- 2140. doi: 10.1016/j.jsxm.2020.08.008. Epub 2020 Sep 15. PMID: 32943375.

This study aimed to assess regulation of the renin-angiotensin system (RAS) in aging-associated Erectile Dysfunction (ED) rat model and evaluate possible options for disease management through pharmacological modulation of the RAS. Penile tissues were harvested from Wistar rats. Experimental results highlighted the essential role of the RAS in modulation of cavernosal fibrosis. The authors demonstrated local expression of angiotensinogen mRNA alongside with major RAS components, which suggests local autonomous functioning of the RAS within penile tissue. Gene expression analysis revealed strong positive correlation between ACE-Ang II-AT1 axis with markers for inflammation and fibrosis. While corpus cavernosum from 24-month-old rats was characterized by increased collagen deposition, protein expression of ACE, AT1, and Mas was shown to be upregulated in the penile tissue of this group. At the same time, penile sections from Mas-knockout mice were also shown to have increased collagen deposition. In conclusion. This study characterizes RAS regulation in aging-associated ED and indicates its important role in cavernosal fibrosis.

Cong R, Wang Y, Wang Y, Zhang Q, Zhou X, Ji C, Yao L, Song N, Meng X. Comprehensive Analysis of lncRNA Expression Pattern and lncRNAmiRNA-mRNA Network in a Rat Model With Cavernous Nerve Injury Erectile Dysfunction. J Sex Med. 2020 Sep;17(9):1603-1617. doi: 10.1016/j. jsxm.2020.05.008. Epub 2020 Jul 13. PMID: 32675050.

The authors aimed to investigate the dysregulated long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and mRNA expression in cavernous nerve (CN) injury-related ED (CNI-ED) and construct a potential lncRNA-miRNA-mRNA network. 22 male Sprague-Dawley rats were divided into bilateral CN crush (BCNC) and Sham groups. Using second-generation highthroughput sequencing technology, the authors analyzed the expression profiles of lncRNA, miRNA, and mRNA of the 2 groups. The BCNC group showed decreased intracavernosal/mean arterial pressure as well as decreased smooth muscle/collagen ratios compared with the Sham group. The RNA sequencing results revealed dysregulated expressions of 65 lncRNA, 14 miRNA, and 750 mRNA in the BCNC group. The study revealed differential expression profiles of lncRNAs, miRNAs, and mRNAs between the BCNC and Sham groups and suggested that these differentially expressed lncRNAs may play critical roles in CNI-ED by regulating apoptosis and fibrosis in the corpus cavernosum via targeting mRNAs or miRNAs.

Peng D, Reed-Maldonado AB, Zhou F, Tan Y, Yuan H, Banie L, Wang G, Tang Y, He L, Lin G, Lue TF. Exosome Released From Schwann Cells May Be Involved in Microenergy Acoustic Pulse-Associated Cavernous Nerve Regeneration. J Sex Med. 2020 Sep;17(9):1618-1628. doi: 10.1016/j.jsxm.2020.05.018. Epub 2020 Jul 12. PMID: 32669249; PMCID: PMC7483773.

Neurogenic erectile dysfunction (ED) is often refractory to treatment because of insufficient functional nerve recovery after injury or insult. The authors aimed to establish a new model in vitro to simulate nerve injury in neurogenic ED and to explore the mechanisms of microenergy acoustic pulse (MAP) in vitro. SpragueDawley rats were used to isolate Schwann cells (SCs), major pelvic ganglion (MPG), and cavernous nerve with MPG (CN/ MPG). SCs were then treated with MAP (0.033 mJ/mm2, 1 Hz, 100 pulses), and SC exosomes were isolated. Neurite outgrowth from MPG and CN/MPG was enhanced by MAP in a dosage response manner, peaking at 100 pulses. MAP promoted SC proliferation, neurotropic factor (brainderived neurotrophic factor, nerve growth factor, and neurotrophin-3) expression, and exosome secretion. SC-derived exosomes significantly enhanced neurite outgrowth from MPG in vitro. This study revealed that neurite outgrowth from MPG was enhanced by MAP and by SC-derived exosomes which were isolated after MAP treatment. This findings indicate that one mechanism by which MAP induces nerve regeneration is by stimulation of SCs to secrete exosomes.

Chen Y, Zhou B, Yu Z, Yuan P, Sun T, Gong J, Zhang Y, Wang T, Wang S, Liu K, Liu J. Baicalein Alleviates Erectile Dysfunction Associated With Streptozotocin-Induced Type I Diabetes by Ameliorating Endothelial Nitric Oxide Synthase Dysfunction, Inhibiting Oxidative Stress and Fibrosis. J Sex Med. 2020 Aug;17(8):1434-1447. doi: 10.1016/j. jsxm.2020.04.390. Epub 2020 Jun 23. PMID: 32586748.

Management of diabetes mellitus induced-erectile dysfunction (DMED) is challenging because of its poor responses to phosphodiesterase type 5 inhibitors. In this study, the authors investigated 12-lipoxygenase (12-LOX) activity and therapeutic effect of its inhibitor, baicalein (BE), on DMED. Intraperitoneal streptozotocin injection was used to induce type I DM, and an apomorphine test was used to evaluate erectile function.

12-LOX upregulation was associated with the progression of type I DMED. After 4 weeks treatment, compared with the DMED group, the DMED + BE group showed better erectile responses to cavernous nerve stimulation. In the DMED + BE group, significantly enhanced endothelial nitric oxide synthase/nitric oxide/cyclic guanosine monophosphate pathway, reduced 12-LOX expression, and inhibited p38 mitogen-activated protein kinase/arginase II/L-arginine pathway were showed in CC relative to the DMED group. In addition, overactivated oxidative stress and fibrosis in the DMED group were both partially ameliorated in the DMED + BE group. In conclusion, 12- LOX might serve as an important factor in the pathogenesis of type I DMED. BE alleviated erectile dysfunction in rats with type I DMED probably by inhibiting 12-LOX expression, ameliorating endothelial nitric oxide synthase dysfunction, as well as suppressing oxidative stress and fibrosis.

Kishimoto T, Kataoka T, Yamamoto Y, Asano G, Fukamoto A, Hotta Y, Maeda Y, Takahashi M, Kanayama HO, Kimura K. High Salt Intake Impairs Erectile Function in Salt-Sensitive Rats Through Mineralocorticoid Receptor Pathway Beyond Its Effect on Blood Pressure. J Sex Med. 2020 Jul;17(7):1280-1287. doi: 10.1016/j.jsxm.2020.04.384. PMID: 32624131.

The authors aimed to investigate whether erectile function is directly impaired by high salt intake and whether selective inhibition of mineralocorticoid receptor (MR) could provide protection from erectile dysfunction (ED). As methodology, 6-week-old male Dahl salt-sensitive rats were randomly divided into 3 groups: normal diet (0.3% NaCl; control, n = 8), high-salt diet (8% NaCl; HS, n = 8), and high-salt diet plus eplerenone (HS + EPL, n = 11). The intracavernosal pressure/mean arterial pressure ratio was significantly lower, whereas systolic blood pressure, MR expression, serum asymmetric dimethylarginine levels, oxidative stress, and levels of inflammatory biomarkers were significantly higher in HS rats than in control rats. EPL administration significantly improved each of these parameters except systolic blood pressure and MR expression. In conclusion, high salt intake directly impaired erectile function in Dahl salt-sensitive rats, whereas selective MR inhibition ameliorated this effect.

HYPOGONADISM

Jósvai A, Török M, Mátrai M, Hetthéssy J, Monori-Kiss A, Makk J, Székács B, Nádasy GL, Várbíró S. Effects of Testosterone Deficiency and Angiotensin II-Induced Hypertension on the Biomechanics of Intramural Coronary Arteries. J Sex Med. 2020 Dec;17(12):2322-2330. doi: 10.1016/j.jsxm.2020.09.003. Epub 2020 Oct 14. PMID: 33067160.

The authors aimed to investigate the effect of testosterone deficiency and hypertension on intramural coronary vessels. Four groups of Sprague-Dawley rats were studied: control male (Co, n=10), orchidectomized male (OCT, n=13), angiotensin (AII) hypertensive male (AII, n=10), and AII hypertensive and OCT (AII + OCT, n=8). After 4 weeks, spontaneous tone and biomechanical properties of the intramural coronary resistance artery were investigated in vitro, by pressure microarteriography. Morphology and biomechanics of the intramural coronaries were evaluated: the outer diameter, wall thickness-to-lumen diameter ratio, and tangential wall stress in the contracted and relaxed states. As results, the outer diameter was reduced in OCT and AII + OCT groups. The increased wall thicknessto-lumen diameter ratio resulted in lower tangential wall stress in AII + OCT rats Spontaneous tone was increased in the hypertensive rats (AII and AII + OCT groups) (on 50 mmHg 7.7 ± 1.8 Co; 6.1 ± 1.4 OCT; 14.5 ± 3.0 AII, and 17.4 ± 4.1 % AII + OCT). The authors concluded that testosterone deficiency and hypertension damage the mechanical adaptation of the vessel wall additively.

Yardimci A, Akkoc RF, Tektemur A, Ulker N, Kaya Tektemur N, Erdem Guzel E, Canpolat S, Ozan IE. Chronic Maternal Tobacco Smoke Exposure and/or Alpha-Lipoic Acid Treatment Causes Long-Term Deterioration of Testis and Sexual Behavior in Adult Male Rats. J Sex Med. 2020 Oct;17(10):1835-1847. doi: 10.1016/j.jsxm.2020.07.002. Epub 2020 Aug 11. PMID: 32798198.

The authors aimed to evaluate the effects of tobacco smoke exposure (TSE) on sexual behavior, reproductive parameters, and testicles in adult male rats and to reveal the possible role of alpha-lipoic acid (ALA) administration on these parameters. Pregnant rats (n = 7 per group) were treated with tobacco smoke (TS), ALA (20 mg/kg), and TS + ALA for a total of 11 weeks. Maternal TSE caused a significant decrease in the number of intromissions compared to the control group. Similarly, ALA decreased erectile function in sexual behavior by decreasing the number of intromissions and intromission ratio in the ALA group compared to the control group. In addition, TSE and ALA treatment caused an impairment of some consummatory sexual behaviors. Also, in parallel with this inhibitory effect, the age of pubertal onset was significantly delayed in the TS + ALA group compared to other groups. Furthermore, histopathological changes in testicular tissue, oxidative stress markers, apoptotic index, and mRNA levels of apoptosis-related genes increased in all treatment groups. As conclusion, maternal TSE and/or ALA treatment may impair sexual behavior in adulthood in male rats because of testicular damage caused by oxidative stress during gonadal development.

EJACULATION DISORDERS

Chen J, Yang J, Huang X, Wang Q, Lu C, Liu S, Chen Y, Ni L. Brain Functional Biomarkers Distinguishing Premature Ejaculation From Anejaculation by ALFF: A Resting-State fMRI Study. J Sex Med. 2020 Dec;17(12):2331-2340. doi: 10.1016/j.jsxm.2020.09.002. Epub 2020 Oct 4. PMID: 33023837.

The authors used resting-state functional magnetic resonance imaging (fMRI) to explore the underlying neural mechanisms in patients with PE and AJ by measuring the amplitude of low-frequency fluctuations (ALFF). Resting-state fMRI data were acquired in 17 PE, 20 AJ patients and 23 matched healthy controls (HC). Differences of ALFF values among the 3 groups were compared. The authors also studyed the correlations between brain regions showing altered ALFF values and scores of Premature Ejaculation Diagnostic Tool (PEDT) in the PE group. There were widespread differences of ALFF values among the 3 groups, which included left anterior cingulate gyrus, precentral and postcentral gyrus, paracentral lobule, superior temporal gyrus, calcarine fissure, putamen; right postcentral gyrus, paracentral lobule, middle temporal gyrus, putamen. Compared with HC, PE patients had greater ALFF in the right inferior frontal gyrus (opercular part), AJ patients had greater ALFF in the left postcentral gyrus. In addition, PE patients exhibited greater ALFF in the left Rolandic operculum, anterior cingulate gyrus, inferior frontal gyrus (orbital part), putamen, and right putamen when compared with AJ patients, as well as decreased ALFF in the right postcentral gyrus. The findings demonstrated that altered ALFF of frontal, parietal cortex, and putamen might help distinguish premature ejaculation from anejaculation.

Yoshizumi M, Yonezawa A, Kimura Y, Watanabe C, Sakurada S, Mizoguchi H. Central Mechanisms of Apomorphine and m-Chlorophenylpiperazine on Synergistic Action for Ejaculation in Rats. J Sex Med. 2020 Nov 23:S1743-6095(20)30989-9. doi: 10.1016/j.jsxm.2020.10.014. Epub ahead of print. PMID: 33243689.

Previous data reported that the combination of the dopamine (DA) receptor agonist apomorphine and the 5-hydroxytryptamine (5-HT2) receptor agonist m-chlorophenylpiperazine (m-CPP) in rats potently and selectively facilitates the ejaculatory response through activation of D2 -like and 5-HT2C receptors, respectively. The aim of this study was to clarify the target level of the proejaculatory effects induced by combination of these agonists. For in vivo behavioral studies, apomorphine and m-CPP were given intracerebroventricularly and intrathecally alone or in combination with either drug administered systemically. Intrathecal m-CPP (10 μg), but not intracerebroventricular m-CPP, evoked the synergistic effects on ejaculation when used in combination with systemically administered apomorphine. Moreover, the synergy between m-CPP and apomorphine was completely abolished by the intrathecal 5-HT2C receptor antagonist SB242084. Intrathecal or intracerebroventricular apomorphine evoked proejaculatory effects in combination with systemically administered m-CPP. These results indicated that the synergistic effects of the drugs on ejaculation were induced at the central level but not at peripheral sites.

PEYRONIE’S DISEASE

Ilg MM, Stafford SJ, Mateus M, Bustin SA, Carpenter MJ, Muneer A, Bivalacqua TJ, Ralph DJ, Cellek S. Phosphodiesterase Type 5 Inhibitors and Selective Estrogen Receptor Modulators Can Prevent But Not Reverse Myofibroblast Transformation in Peyronie’s Disease. J Sex Med. 2020 Oct;17(10):1848-1864. doi: 10.1016/j. jsxm.2020.06.022. Epub 2020 Aug 5. PMID: 32771352.

The authors investigated whether PDE5is and elective estrogen receptor modulators (SERMs) can reverse transforming growth factor beta 1 (TGF-β1)-induced myofibroblast transformation and determine the point of no return. In-Cell enzyme-linked immunosorbent assay was used to quantify TGF-β1-induced myofibroblast transformation of human primary fibroblasts isolated from tunica albuginea (TA) of patients undergoing surgery for treatment of PD. Extracellular matrix production and collagen contraction assays were used as secondary assays. PDE5i (vardenafil) and SERM (tamoxifen) were applied at various time points after TGF-β1.Vardenafil or tamoxifen could not reverse the myofibroblast traits of alpha-smooth muscle actin expression and extracellular matrix production. Phosphodiesterase 5A and estrogen receptor (ER)-β were downregulated after 72 hours, and estrogen receptor -α protein could not be quantified. Tamoxifen could prevent myofibroblast transformation until 36 hours after TGF-β1 treatment, whereas vardenafil could prevent only 24 hours after TGF-β1 treatment. This is the first study to demonstrate that timing for administration of drugs affecting myofibroblast transformation appears to be vital in in vitro models of PD, where 36 hours of TGF-β1 treatment can be suggested as a “point of no return” for myofibroblast transformation.

ONCOLOGY

Randolph JT, Pak ES, Koontz BF, Hannan JL. Ex Vivo Radiation Leads to Opposing Neurite Growth in Whole Ganglia vs Dissociated Cultured Pelvic Neurons. J Sex Med. 2020 Aug;17(8):1423-1433. doi: 10.1016/j.jsxm.2020.04.385. Epub 2020 Jun 20. PMID: 32576498.

Prostatic radiation therapy (RT) often causes erectile dysfunction (ED) and the mechanisms governing RT-induced ED are unclear. The aim of the study was to determine the effects of ex vivo RT on major pelvic ganglion (MPG) neuron survival, and neurite growth in whole vs dissociated culture. MPGs were removed and irradiated (0 or 8 Gy) from male Sprague Dawley rats. For dissociated culture, MPG neurons were digested in collagenase/dispase and cultured on coverslips. RT increased apoptosis in dissociated neurons measured by terminal deoxynucleotidyl transferase dUTP nick end labeling) and whole MPG culture via upregulation of caspase 3 gene expression. Nitrergic neurons were markedly decreased in irradiated dissociated culture, while nNOS gene expression was upregulated in irradiated whole organ culture. The proportion of dissociated sympathetic neurons and whole organ TH gene expression remained unchanged after RT. The 2 different culture methods demonstrated opposing neurite growth after RT indicating the importance of supporting cell network to promote pelvic neuron neuritogenesis and survival following RT.

PRIAPISM

Musicki B, Karakus S, La Favor JD, Chen H, Silva FH, Sturny M, Zirkin BR, Burnett AL. TSPO ligand FGIN-1-27 controls priapism in sickle cell mice via endogenous testosterone production. J Cell Physiol. 2020 Sep 24. doi: 10.1002/jcp.30075. Epub ahead of print. PMID: 32974910.

Priapism is common among patients with sickle cell disease (SCD). Hypogonadism is also common in patients with SCD. The authors hypothesized that the stimulation of endogenous testosterone production decreases priapism by normalizing molecular signaling involved in penile erection without decreasing intratesticular testosterone production, which would affect fertility. Treatment of SCD mice with FGIN-1-27, a ligand for translocator protein (TSPO) that mobilizes cholesterol to the inner mitochondrial membrane, resulted in eugonadal levels of serum testosterone without decreasing intratesticular testosterone production. Normalized testosterone levels, in turn, decreased priapism. These results indicate that pharmacologic activation of TSPO could be a novel, targetable pathway for treating hypogonadal men, particularly patients with SCD, without adverse effects on fertility.

ORGASM / SEXUAL DESIRE

González Cautela BV, Quintana GR, Akerman J, Pfaus JG. Acute caffeine reverses the disruptive effects of chronic fluoxetine on the sexual behavior of female and male rats. Psychopharmacology (Berl). 2020 Nov 26. doi: 10.1007/s00213-020-05728-0. Epub ahead of print. PMID: 33242109.

Sexual side effects of chronic treatment with selective serotonin reuptake inhibitors (SSRIs) in humans include anorgasmia and loss of sexual desire and/or arousal which interferes with treatment compliance. There are few options at present to reduce these effects. This study examined whether acute treatment with caffeine (CAF) versus vehicle could ameliorate the disruption of appetitive and consummatory measures of copulatory behavior produced by chronic fluoxetine in adult, sexually active female or male rats. Sexually experienced female or male rats received daily injections of fluoxetine (FLU) over a 24-day period and were tested for sexual behaviors. Chronic FLU reduced solicitations and lordosis over time in females and reduced the number of ejaculations in males. Both doses of CAF restored solicitations and lordosis in females and ejaculations in males. Stimulation of sympathetic outflow by CAF may constitute a readily accessible on-demand treatment for the sexual side-effects of SSRIs.

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