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Erectile Dysfunction

The Combination of High-Fat Diet and Oral Marijuana Promotes the Development of Fibrosis in the Mouse Corpora Cavernosa.

Nguyen S, Mangubat M, Eleswarapu S, Wilson JB, Molina J, Abraham A, Artaza JN, Friedman TC, Ferrini MG. Sex Med. 2021 Apr;9(2):100312. doi: 10.1016/j.esxm.2020.100312. Epub 2021 Feb 1. PMID: 33540365; PMCID: PMC8072182.

The authors aimed to determine the effects of diet and oral cannabis extract on fibrosis and oxidative stress within the corpora cavernosa of mice. This was a pilot animal study in which groups of 2-month old C57BL/6J male mice were fed a normal chow diet (NCD) or high-fat diet (HFD) daily and treated with or without either marijuana (MJ) or Δ-9-tetrahydrocannabinol extract (THC) extract for 2 months. The combination of HFD with MJ resulted in: (i) a decrease in the smooth/collagen ratio in the corpora cavernosa, (ii) an increase in alpha-smooth muscle actin expression in the tunica albuginea compatible with myofibroblast proliferation, and (iii) a decrease in heme oxygenase 1 expression indicating an increase in oxidative stress. In conclusion, HFD combined with oral MJ extract led to structural alterations in erectile tissue that are associated with accelerated corporal fibrosis.

miR-195-5p Regulates the Phenotype Switch of CCSM Cells by Targeting Smad7.

Zhang J, Zhang X, Cong S, Zhang J, Zhang A, Pan L, Ma J. Sex Med. 2021 Jun;9(3):100349. doi: 10.1016/j.esxm.2021.100349. Epub 2021 Jun 1. PMID: 34087534; PMCID: PMC8240331.

This study aimed to investigate the role of miR-195-5p in regulating the phenotype switch of the corpus cavernosum smooth muscle (CCSM) cells. A small mother against decapentaplegic 7(Smad7) virus vector and a miR-195-5p mimics or an si-Smad7 viral vector and a miR-195-5p inhibitor were transfected into CCSM cells. Overexpressed miR-195-5p promoted the transformation of CCSM cells from a contractile type to a synthetic type. Meanwhile, the migration ability and proliferation ability of CCSM cells increased, and the apoptosis rate decreased. The expression-silencing of miR-195-5p gave rise to the opposite effect. The results of the rescue experiment demonstrated that overexpressed Smad7 rescued the inhibitory of the switch of the CCSM cell phenotype from the contractile type to the synthesis type caused by overexpression of miR-195-5p alone.

Intracavernous Injection of Autologous Platelet-Rich Plasma Ameliorates Hyperlipidemia-Associated Erectile Dysfunction in a Rat Model.

Huang YC, Wu CT, Chen MF, Kuo YH, Li JM, Shi CS. Sex Med. 2021 Apr;9(2):100317. doi: 10.1016/j.esxm.2020.100317. Epub 2021 Jan 30. PMID: 33529811; PMCID: PMC8072173.

The authors investigated latelet-rich plasma (PRP) in a rat model of hyperlipidemia-associated erectile dysfunction (ED). Thirty 2-month-old male Sprague-Dawley rats were randomly divided into 3 groups. 20 rats were fed a high-fat diet for 5 months and were randomly divided into 2 groups: (i) rats in the H group received supernatant injection into the corpus cavernosum weekly for 4 weeks; (ii) rats in the H + PRP group received PRP injection into the corpus cavernosum weekly for 4 weeks. 10 rats were fed a standard diet for 5 months and received supernatant injection into the corpus cavernosum weekly for 4 weeks (N group). 7 days after the 4th injection, all rats underwent erectile function testing. Erectile function was evaluated by measuring intracavernous pressure (ICP) and mean arterial pressure (MAP). Intracavernous pressure/MAP and area under the curve/MAP ratios were significantly higher in the N and H + PRP groups than in the H group. Insulin-like growth factor-1, brain-derived neurotrophic factor, and vascular endothelial growth factor levels were significantly higher in the H + PRP group than in the N and H groups.

Effects of androgen on extracellular vesicles from endothelial cells in rat penile corpus cavernosum.

Yan LT, Yang ZH, Lin H, Jiang J, Jiang R. Andrology. 2021 May;9(3):1010-1017. doi: 10.1111/andr.12980. Epub 2021 Feb 9. PMID: 33484224.

It was reported that eNOS was expressed in androgen may regulate erectile function by affect the release of extracellular vesicles (EVs) from endothelial cells. The authors aimed to investigate whether androgen affects the production of EVs and nitric oxide (NO) in endothelial cells of rat penile corpus cavernosum. Endothelial cells were treated with different concentrations of dihydrotestosterone (DHT) in a cell culture medium as follows: no-androgen group (NA group, DHT 0 nmol/L), very-low androgen group (VLA group, DHT 0.1 nmol/L), low androgen group (LA group, DHT 1 nmol/L), and physiological concentrations androgen group (PA group, DHT 10 nmol/L). Positive expression of CD9, CD63, TSG101, and eNOS was found in isolated EVs. The concentration of EVs was lower in the NA group compared with other groups. The expression of eNOS and the concentration of NO was lower in the NA group than that in other groups. The authors concluded that the decrease in eNOS-expressing EVs is one mechanism of NO reduction in endothelial cells of rat corpus cavernosum caused by low androgen levels.

Low androgen status inhibits erectile function by increasing pyroptosis in rat corpus cavernosum.

Chen ZB, Li G, Lin H, Jiang J, Jiang R. Andrology. 2021 Jul;9(4):1264-1274. doi: 10.1111/andr.12995. Epub 2021 Mar 11. PMID: 33657666.

The authors aimed to investigate whether low androgen status inhibits erectile function of rats by inducing pyroptosis in the corpus cavernosum (CC). Thirty-six eight-weeks-old healthy male Sprague-Dawley rats were divided into six groups: sham-operated group (4w sham, 8w sham), castration group (4w cast, 8w cast), and castration + testosterone (T) group (4w cast + T, 8w cast + T). The rats in castration + T groups were injected with testosterone propionate subcutaneously. After 4 and 8 weeks, the ratio of maximum intracavernous pressure (ICPmax)/mean arterial pressure (MAP), the level of serum T, the concentration of nitric oxide (NO) and interleukin-1β (IL-1β), the expression of NOD-like receptor pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC), Caspase-1 p20, gasdermin D-N (GSDMD-N), transforming growth factor β1 (TGF-β1), collagen-I, and collagen-III, the ratio of smooth muscle/collagen (SM/C), and the proportion of pyroptotic cells in the CC were analyzed. The ratio of ICPmax/MAP (3/5 V) and SM/C, the level of NO and serum T was significantly decreased in castration groups when compared to other groups. NLRP3, ASC, Caspase-1, and GSDMD were mainly expressed in the cytoplasm of smooth muscle cells (SMCs) and endothelial cells (ECs) in the CC. The expression of NLRP3, ASC, Caspase-1p20, GSDMD-N, IL-1β, TGF-β1, collagen-I, and collagen-III was significantly increased in castration groups when compared with other groups. The proportion of pyroptotic cells in the CC was increased significantly in castration groups when compared with other groups. The authors concluded that low androgen status inhibits erectile function of rats by promoting CC fibrosis and reducing NO synthesis through pyroptosis of SMCs and ECs in the CC.

Increased Level of Tumor Necrosis Factor-Alpha (TNF-α) Leads to Downregulation of Nitrergic Neurons Following Bilateral Cavernous Nerve Injury and Modulates Penile Smooth Tone.

Matsui H, Sopko NA, Campbell JD, Liu X, Reinhardt A, Weyne E, Castiglione F, Albersen M, Hannan JL, Bivalacqua TJ. J Sex Med. 2021 Jul;18(7):1181-1190. doi: 10.1016/j.jsxm.2021.05.001. PMID: 34274042.

The aim of this study was to examine temporal changes of TNF-α, after bilateral cavernous nerve (CN) injury (BCNI), to evaluate effect of exogenous TNF-α on neurite outgrowth from major pelvic ganglion (MPG), and to investigate effect of TNF-α signal inhibition to evaluate effects of TNF-α on penile tone with TNF-α receptor knockout mice (TNFRKO). Seventy Sprague-Dawley rats were randomized to undergo BCNI or sham surgery. Sham rats’ MPGs were harvested after 48 hours, whereas BCNI groups’ MPGs were at 6, 12, 24, 48 hours, 7, or 14 days after surgery. qPCR was used to evaluate gene expression of markers for neuroinflammation in MPGs. BCNI increased gene and protein expression of TNF-α in MPGs. Exogenous TNF-α inhibited MPG neurite outgrowth. MPGs cultured with TNF-α had decreased gene expression of nNOS. MPGs cultured with TNF-α had shorter nNOS+ neurites than TH+ neurites. Gene expression of nNOS was enhanced in TNFRKO mice compared to WT mice. WT mice showed enhanced smooth muscle contraction of penises of WT mice was enhanced to EFS, compared to TNFKO. Penile smooth-muscle relaxation to EFS was greater in TNFKO mice compared to WT. The authors concluded that TNF-α inhibition may prevent ED after prostatectomy.

Apelin-13 Protects Corpus Cavernosum Against Fibrosis Induced by High-Fat Diet in an MMP-Dependent Mechanism.

Sturny M, Anguenot L, Costa-Fraga FP, Bragina ME, Lima AM, da Silva RF, Fraga-Silva RA, Stergiopulos N. J Sex Med. 2021 May;18(5):875-888. doi: 10.1016/j.jsxm.2021.02.004. Epub 2021 Apr 15. PMID: 33863684.

The authors aimed to investigate the effect of chronic Apelin treatment on the corpus cavernosum structure of hypercholesterolemic mice. Apolipoprotein gene-deleted (ApoE-/-) mice were fed with a Western diet for 11 weeks and received Apelin-13 or vehicle during the last 3 weeks. Penile samples were obtained for histological and biochemical analyses to assess the intracorporal collagen content and key proteins expression. Furthermore, the effect of Apelin-13 was evaluated in cultured NIH3T3 mouse fibroblasts stimulated with TGF-β. Interestingly, 3 weeks of Apelin-13 treatment strongly reduced intracavernosal collagen content. In addition, Apelin-13 enhanced total matrix metalloproteinase (MMP) activity in the mice penis, which was associated with an increased protein expression of MMP-1, MMP-3, MMP-8, and MMP-9, while tissue inhibitor of metalloproteinase were unaltered. These beneficial actions were not associated with changes in nNOS or eNOS protein expression, intracavernosal reactive oxygen species content, or atherosclerotic plaque deposition. These results point out Apelin/APJ system as a potential target to treat intracavernosal fibrosis-related disorders.

Expression of MicroRNAs (miR-15b, miR-16, miR-138, miR-221, and miR-222) as Biomarkers of Endothelial Corpus Cavernosum Dysfunction in a Diabetic Alcoholic Murine Model.

Tiraboschi RB, Neto FSL, da Cunha Tirapelli DP, de Bessa J Jr, Miranda EP, de Assis Cirino ML, Tirapelli LF, Tucci S Jr, Molina CAF. Sex Med. 2021 Apr;9(2):100326. doi: 10.1016/j.esxm.2021.100326. Epub 2021 Mar 3. PMID: 33676226; PMCID: PMC8072178.

The authors aimed to investigate the expression of miR-15b, miR-16, miR-138, miR-221, and miR-222 in corpus cavernosum (CC) and peripheral blood in a rat model of endothelium dysfunction secondary to diabetes (DM) and alcohol consumption to assess potential endothelial lesion biomarkers. Twenty males Wistar rats were divided into 4 groups: control group (C), alcohol consumption group (A), diabetic group (D), diabetic-alcohol consumption group (D + A). The authors found that 3 miRNAs (miR-16, miR-221, and miR-222) were downregulated in the CC in the D+A group, while all 5 miRNAs were downregulated in the blood of D and D + A groups. In conclusion, miRNAs downregulation was identified in both CC and blood notably in DM associated with alcohol consumption animals (D + A), the greatest endothelial injury potential group.

Beneficial Effects of Human Umbilical Cord Blood Mononuclear Cells on Persistent Erectile Dysfunction After Treatment of 5-Alpha Reductase Inhibitor in Rats.

Oztekin CV, Yilmaz-Oral D, Kaya-Sezginer E, Kirlangic OF, Ozen FZ, Ozdal B, Topcu HO, Gur S. J Sex Med. 2021 May;18(5):889-899. doi: 10.1016/j.jsxm.2021.02.005. Epub 2021 Mar 27. PMID: 33785264.

Effects of human umbilical cord blood (HUCB) as a valuable source for stem cell-based therapies have not been studied in persistent post-5-alpha reductase inhibitors (5ARI) erectile dysfunction (PPED). This study aimed to determine the effect of intracavernosal injection of HUCB mononuclear cells (MNCs) on ED associated with dutasteride treatment. Twenty five adult male Sprague-Dawley rats were divided into 5 groups (n = 5 per group): (i) control, (ii) 8-week dutasteride (0.5 mg/kg/day, in drinking water), (iii) 12-week dutasteride, (iv) 8-week dutasteride+HUCB-MNCs (1 × 106) and (v) 12-week dutasteride+HUCB-MNCs. HUCB-MNCs were administered intracavernosally after eight weeks of dutasteride treatment. Erectile responses in the dutasteride-treated groups were significantly decreased compared with controls, persisting after 4-wk of washout. HUCB-MNCs restored diminished intracavernosal pressure responses, acetylcholine-, sodium nitroprusside-, sildenafil-induced relaxations, and increased phenylephrine and electrical field stimulation (EFS)-induced contractions. Decreased EFS-induced relaxations in dutasteride-treated groups were not restored by HUCB-MNCs. Increased PDE5 and reduced nNOS expressions in dutasteride groups were restored by HUCB-MNCs in the 12-week dutasteride group. HUCB-MNCs reversed the decreased smooth muscle/collagen ratio in dutasteride-treated tissues. This study demonstrates the corrective potential of HUCB-MNCs on some persistent structural and functional deterioration caused by 5ARI treatment in rats, which may encourage further evaluation of HUCB-MNCs in men with PPED.

CXCL5 Cytokine Is a Major Factor in Platelet-Rich Plasma’s Preservation of Erectile Function in Rats After Bilateral Cavernous Nerve Injury.

Wu YN, Liao CH, Chen KC, Chiang HS. J Sex Med. 2021 Apr;18(4):698-710. doi: 10.1016/j.jsxm.2020.12.016. Epub 2021 Mar 23. PMID: 33741291.

This study aimed to determine factors released from platelet-rich plasma (PRP) and explore their role in mediating preservation of erectile function (EF) in a rat model of cavernous nerve (CN) injury. Male Sprague-Dawley rats were used in this study. The authors determined the expression patterns of C-X-C motif chemokine ligand 5 (CXCL5) and receptors in the major pelvic ganglion (MPG) and corpus cavernosum via immunostaining. The PRP contained high levels of CXCL5. MPG neurons expressed CXCL5 and CXCR2. PRP intracavernous injection stabilized CXCR2 and increased CXCL5 expression in the MPG after BCNC, thus enhancing neuroprotection. CXCL5 injection improved BCNC-induced erectile dysfunction by preventing smooth muscle atrophy. This study provides evidence for the role of CXCL5 and CXCR2 as mediators of PRP effects in the preservation of EF after CN injury.

Caspase Signaling in ED Patients and Animal Models.

Martin S, Harrington DA, Ohlander S, Stupp SI, McVary KT, Podlasek CA. J Sex Med. 2021 Apr;18(4):711-722. doi: 10.1016/j.jsxm.2021.01.175. Epub 2021 Mar 9. PMID: 33707045; PMCID: PMC8068676.

The authors examined the mechanism of how apoptosis occurs in erectile dysfunction (ED) patients and cavernous nerve (CN) injury rat models to determine points of intervention for therapy development. Immunohistochemical and western analyses for caspase 3-cleaved, caspase-8 and caspase-9 (pro and active forms) were performed in corpora cavernosal tissue from Peyronie’s, prostatectomy and diabetic ED patients (n = 33), penis from adult Sprague Dawley rats that underwent CN crush (n = 24), BB/WOR diabetic and control rats (n = 8), and aged rats (n = 9). Caspase 3-cleaved was observed in corpora cavernosa from Peyronie’s patients and at higher abundance in prostatectomy and diabetic tissues. Apoptosis takes place primarily through the extrinsic (caspase 8) pathway in penis tissue of ED patients. In the CN crushed rat, caspase 3-cleaved was abundant from 1-9 days after injury, and apoptosis takes place primarily via the intrinsic (caspase 9) pathway. Caspase 9 was first observed and most abundant in a layer under the tunica, and after several days was observed in the lining of and between the sinuses of the corpora cavernosa. Caspase 8 was initially observed at low abundance in the rat corpora cavernosa and was not observed at later time points after CN injury. The authors concluded that apoptosis takes place primarily through the extrinsic caspase 8 dependent pathway in ED patients and via the intrinsic caspase 9 dependent pathway in commonly used CN crush ED models. This is an important consideration for study design and interpretation that must be taken into account for therapy development and testing of drugs.

Macrophage-Specific Toll Like Receptor 9 (TLR9) Causes Corpus Cavernosum Dysfunction in Mice Fed a High Fat Diet.

Priviero F, Calmasini F, Dela Justina V, Wenceslau CF, McCarthy CG, Webb RC. J Sex Med. 2021 Apr;18(4):723-731. doi: 10.1016/j.jsxm.2021.01.180. Epub 2021 Mar 16. PMID: 33741290; PMCID: PMC8068605.

Since obesity triggers an inflammatory process, the authors aimed to investigate the hypothesis that in obesity, Toll-like receptor 9 (TLR9) activation leads to increased TNF-α levels and impairment in corpus cavernosum (CC) reactivity. Four-week old male C57BL6 (WT) and TLR9 mutant (TLR9MUT) mice were fed a standard chow or high fat diet (HFD) for 12 weeks. Body weight and nonfasting blood glucose were analyzed. Contractile and relaxation responses of the CC were evaluated by electrical field stimulation and concentration response curves to phenylephrine and acetylcholine. After 12 weeks of HFD both WT and TLR9MUT mice had increased body weight and nonfasting blood glucose compared to standard chow. In the CC, acetylcholine-induced relaxation was not changed. This findings indicate that CC dysfunction observed in obesity is at least in part mediated by the production of TNF-α upon activation of TLR9 expressed in the macrophages.

Oral Administration of the p75 Neurotrophin Receptor Modulator, LM11A-31, Improves Erectile Function in a Mouse Model of Cavernous Nerve Injury.

Yin GN, Ock J, Limanjaya A, Minh NN, Hong SS, Yang T, Longo FM, Ryu JK, Suh JK. J Sex Med. 2021 Jan;18(1):17-28. doi: 10.1016/j.jsxm.2020.10.015. Epub 2020 Nov 24. PMID: 33243690.

This study aimed to investigate the therapeutic effect of oral administration of LM11A-31, a small molecule p75 neurotrophin receptor (p75NTR) ligand and proNGF antagonist, in a mouse model of bilateral cavernous nerve injury (CNI), which mimics nerve injury-induced erectile dysfunction after radical prostatectomy. 8-week-old male C57BL/6 mice were divided into sham operation and CNI groups. Each group was divided into 2 subgroups: phosphate-buffered saline and LM11A-31 (50 mg/kg/day). Erectile function was decreased in the CNI group (44% of the sham operation group), while administration of LM11A-31 led to a significant improvement of erectile function (70% of the sham operation group) in association with increased neurovascular content, including cavernous endothelial cells, pericytes, and neuronal processes. Immunohistochemical and Western blot analyses showed significantly increased p75NTR expression in the dorsal nerve of CNI mice, which was attenuated by LM11A-31 treatment. Protein expression of active PI3K, AKT, and endothelial nitric oxide synthase was increased, and cell death and c-Jun N-terminal kinase signaling was significantly attenuated after LM11A-31 treatment. The authors concluded that specific inhibition of the proNGF-p75NTR degenerative signaling via oral administration of LM11A-31 represents a novel therapeutic strategy for erectile dysfunction induced by nerve injury.

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

Chen Y, Qi T, Zhu SG, Li H, Feng JX, Zhang B, Li SX, Ma S, Ma Q, Chu QJ, Yang WT, Chen J. Andrologia. 2021 Jul 30:e14194. doi: 10.1111/and.14194. Epub ahead of print. PMID: 34328658.

The authors aimed 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. 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. 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.

Extracorporeal shock wave therapy combined with engineered mesenchymal stem cells expressing stromal cell-derived factor-1 can improve erectile dysfunction in streptozotocin-induced diabetic rats.

Shin D, Jeon SH, Tian WJ, Kwon EB, Kim GE, Bae WJ, Cho HJ, Hong SH, Lee JY, Kim SW. Transl Androl Urol. 2021 Jun;10(6):2362-2372. doi: 10.21037/tau-21-79. PMID: 34295723; PMCID: PMC8261440.

The objective of this study was to investigate whether extracorporeal shock wave therapy (ESWT)  in combination with stromal cell-derived factor-1 expressing engineered mesenchymal stem cell (SDF-1 eMSC) therapy can have synergistic effects on erectile dysfunction (ED) in streptozotocin-induced diabetic (DM) rats. Fifty 8-week-old male Sprague-Dawley rats were randomly divided into five groups: (I) Normal group, (II) DM ED, (III) DM ED + ESWT group, (IV) DM ED + SDF-1 eMSC group, and (V) DM ED + ESWT + SDF-1 eMSC group. Each groups were treated with bilateral injections of SDF-1 eMSC or ESWT following the experiment protocol for eight weeks. The ratio of ICP/MAP was distinctly higher in the DM ED + ESWT + SDF-1 eMSC group than that in the DM ED group. Additionally, ESWT increased the intensity of SDF-1 expression in the corpus cavernosum. ESWT + SDF-1 eMSC treatment also induced neuronal nitric oxide synthase (nNOS) and NO/cGMP expression in the corpus cavernosum. Combined treatment of ESWT with SDF-1 eMSC treatment could be used as a potential and effective synergistic treatment for DM ED.

Transplantation of Human Gingiva-Derived Mesenchymal Stem Cells Ameliorates Neurotic Erectile Dysfunction in a Rat Model.

Wu J, Chen Z, Zhong F, Yang W, Ouyang X, Ma X, Zheng S, Wei H. Front Bioeng Biotechnol. 2021 Jun 21;9:630076. doi: 10.3389/fbioe.2021.630076. PMID: 34235136; PMCID: PMC8255925.

The authors injected the human gingiva-derived mesenchymal stem cells  (hGMSCs) around the bilateral major pelvic ganglia (MPG) in a rat model of cavernous nerve injury (CNI) and evaluated their efficacy. The results showed that treatment of hGMSCs could significantly promote the recovery of erectile function, enhance smooth muscle and endothelial content, restore neuronal nitric oxide synthase (nNOS) expression, and attenuate cell apoptosis in penile tissue. Moreover, penile fibrosis was significantly alleviated after hGMSC administration. In addition, potential mechanism exploration indicated that hGMSCs might exert its functions via skewed macrophage polarity from M1 toward M2 anti-inflammatory phenotype.

Inhibition of inducible nitric oxide synthase improved erectile dysfunction in rats with type 1 diabetes.

Liu L, Wang X, Liu K, Kang J, Wang S, Song Y, Zhou K, Yi L, Liu X. Andrologia. 2021 Sep;53(8):e14138. doi: 10.1111/and.14138. Epub 2021 Jun 16. PMID: 34137064.

The purpose of this study was to investigate the role of iNOS in diabetes mellitus erectile dysfunction (DMED). The authors developed a type 1 diabetes mellitus rat model using streptozotocin and selected those that developed DMED. Then, they injected these rats with the 1400W, an iNOS inhibitor, for 10 weeks and subsequently assessed their ED. Lastly, they performed various molecular studies and histopathological analyses of penile tissues collected from these rats after the experiments. Through the histopathological studies,the authors also found that the treatment restored the ratios of the smooth muscle to collagen fibres, delayed the development of microvascular injury and alleviated the oxidative stress caused by hyperglycaemia.

Hypogonadism

Androgen-dependent miR-125a-5p targets LYPLA1 and regulates global protein palmitoylation level in late-onset hypogonadism males.

Qu M, Zhao Y, Qing X, Zhang X, Li H. J Cell Physiol. 2021 Jun;236(6):4738-4749. doi: 10.1002/jcp.30195. Epub 2020 Dec 7. PMID: 33284463.

This study demonstrated that plasma miR-125a-5p was upregulated after testosterone supplementation in both late-onset hypogonadism (LOH) patients and castrated mice, and positively associated with the testosterone concentrations, suggesting direct regulation of miR-125a-5p expression by testosterone. Androgen response element in the promoter of miR-125a-5p was subsequently identified. Target gene screening and confirmation verified that LYPLA1, encoding acyl-protein thioesterase 1 which catalyzed protein depalmitoylation process, was a target gene of miR-125a-5p. The results suggested that testosterone could regulate global palmitoylation level through miR-125a-5p/LYPLA1 signaling pathway.

Morphometric analysis and redox state of the testicles in nandrolone decanoate and swimming treated adult male rats.

Sretenovic J, Joksimovic Jovic J, Srejovic I, Zivkovic V, Mihajlovic K, Labudovic-Borovic M, Trifunovic S, Milosevic V, Lazic D, Bolevich S, Jakovljevic V, Milosavljevic Z. Basic Clin Androl. 2021 Jul 15;31(1):17. doi: 10.1186/s12610-021-00134-8. PMID: 34261436; PMCID: PMC8281612.

The aim of this study was to investigate the effects of four-week administration of nandrolone decanoate and swimming training alone or in combination on morphometric parameters, androgen receptor (AR) and redox state in testicle tissue. The study included Wistar albino male rats, 10 weeks old, classified into 4 groups: control (T-N-), nandrolone (T-N+), swimming training (T+N-) and swimming training with nandrolone (T+N+). The isolated testicles were measured, left testicles were routinely processed for histological analysis, while right testicles were homogenized and prepared for the analysis of the following oxidative stress biomarkers: index of lipid peroxidation (TBARS), nitrites, catalase, superoxide dismutase (SOD), and reduced glutathione (GSH). Diameter, as well as cross-section area of seminiferous tubules were decreased by 10 % and 21 % (respectively) in the T-N+ group and by 15% and 41 % (respectively) in the T+N+ group compared to control. Interstitium of the testicles was decreased in all experimental groups. Reduction of immunoreactivity of AR in T-N+ group was 22 %, in T+N+ group was 9 % compared to control. TBARS levels were increased in T+N- and T+N+ groups. Swimming alone or combined with nandrolone decreased the level of GSH compared to control. SOD activity was decreased in T-N+ and T+N+ groups compared to control.

Ejaculation Disorders

Central Mechanisms of Apomorphine and m-Chlorophenylpiperazine on Synergistic Action for Ejaculation in Rats.

Yoshizumi M, Yonezawa A, Kimura Y, Watanabe C, Sakurada S, Mizoguchi H. J Sex Med. 2021 Feb;18(2):231-239. doi: 10.1016/j.jsxm.2020.10.014. Epub 2020 Nov 23. PMID: 33243689.

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. Intrathecal m-CPP (10 μg), but not intracerebroventricular m-CPP, evoked the synergistic effects on ejaculation when used in combination with systemically administered apomorphine (0.1 mg/kg, subcutaneous). Moreover, the synergy between m-CPP and apomorphine was completely abolished by the intrathecal 5-HT2C receptor antagonist SB242084 (10 μg). Intrathecal or intracerebroventricular apomorphine (1-10 μg) evoked proejaculatory effects in combination with systemically administered m-CPP (0.3 mg/kg, intraperitoneal). The selective peripherally acting D2-like receptor agonist carmoxirole did not evoke ejaculation when used in combination with m-CPP. Furthermore, isolated rat seminal vesicles were completely insensitive to the combination of apomorphine and 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. This findings also suggested that the 5-HT2C receptor mediated the stimulation of the spinal ejaculatory pattern generator and was synergistically potentiated by the spinal DA receptor and that activation of the supraspinal DA receptor was also involved in mediating these synergistic effects.

Spinal Cord Injury Causes Reduction of Galanin and Gastrin Releasing Peptide mRNA Expression in the Spinal Ejaculation Generator of Male Rats.

Wiggins JW, Sledd JE, Coolen LM. Front Neurol. 2021 Jun 22;12:670536. doi: 10.3389/fneur.2021.670536. PMID: 34239493; PMCID: PMC8258150.

It was previously demonstrated that spinal contusion injury in male rats caused reduction of GRP-immunoreactivity, but not galanin-immunoreactivity in  lumbar spinothalamic (LSt)  cells, indicative of reduced gastrin releasing peptide (GRP) levels, but inconclusive results for galanin. The current study further tests the hypothesis that contusion injury causes a disruption of GRP and galanin mRNA in LSt cells. Male rats received mid-thoracic contusion injury and galanin and GRP mRNA were visualized 8 weeks later in the lumbar spinal cord using fluorescent in situ hybridization. Spinal cord injury (SCI) significantly reduced GRP and galanin mRNA in LSt cells. Galanin expression was higher in LSt cells compared to GRP. However, expression of the two transcripts were positively correlated in LSt cells in both sham and SCI animals, suggesting that expression for the two neuropeptides may be co-regulated. GRP and galanin are both essential for triggering ejaculation and thus such reduction may contribute to ejaculatory dysfunction following SCI in rats.

Physiological and pharmacological impact of oxytocin on epididymal propulsion during the ejaculatory process in rodents and men.

Stadler B, Nowell CJ, Whittaker MR, Arnhold S, Pilatz A, Wagenlehner FM, Exintaris B, Middendorff R. FASEB J. 2021 Jun;35(6):e21639. doi: 10.1096/fj.202100435R. PMID: 34041782.

The authors investigated the effect of oxytocin (suggested to exert effects during ejaculation) on defined segments of the rat and human epididymis using live imaging. The results indicate that it is the very last part of the epididymis, segment 19 (S19) in rat and likewise segment 9 in human, which responds in a uniquely strong and rapid manner to oxytocin (similar to noradrenaline). The reaction of S19 to oxytocin was concentration-dependent and could be inhibited by pretreatment with oxytocin antagonists (atosiban and cligosiban), but not with an arginine vasopressin 1A antagonist (SR49059). In both rat and human tissue, pretreatment with the alpha-1 adrenoreceptor antagonist tamsulosin inhibited the response to noradrenaline, whereas the effect of oxytocin was unimpaired. This data (from men and rodents) strongly suggest that the hormone oxytocin is involved in the ejaculatory process. Thus, oxytocin-based medications might be a promising non-adrenergic treatment option for ejaculatory disorders.

Peyronie’s Disease

RNA-sequencing profiling analysis of pericyte-derived extracellular vesicle-mimetic nanovesicles-regulated genes in primary cultured fibroblasts from normal and Peyronie’s disease penile tunica albuginea.

Yin GN, Piao S, Liu Z, Wang L, Ock J, Kwon MH, Kim DK, Gho YS, Suh JK, Ryu JK. BMC Urol. 2021 Aug 6;21(1):103. doi: 10.1186/s12894-021-00872-x. PMID: 34362357; PMCID: PMC8344132.

Extracellular vesicle (EV)–mimetic nanovesicles (NVs) have attracted attention regarding intercellular communication between cells in the field of fibrosis. However, the global gene expression of pericyte-derived EV–mimetic NVs (PC–NVs) in regulating fibrosis remains unknown. The authors  used RNA-sequencing technology to investigate the potential target genes regulated by PC–NVs in primary fibroblasts derived from human Peyronie Disease (PD) plaque. Human primary fibroblasts derived from normal and PD patients was cultured and treated with cavernosum pericytes isolated extracellular vesicle (EV)–mimetic nanovesicles (NVs). A total of 4135 genes showed significantly differential expression in the normal fibroblasts, PD fibroblasts, and PD fibroblasts treated with PC–NVs. However, only 91 contra-regulated genes were detected among the three libraries. In conclusion, the gene expression profiling results suggested that these validated genes may be good targets for understanding potential mechanisms and conducting molecular studies into PD.

Mechanical characterization of fibrotic and mineralized tissue in Peyronie’s disease.

Brady L, Stender CJ, Wang YN, Schade GR, Maxwell AD, Wessells H, Ledoux WR. Int J Impot Res. 2021 May 25. doi: 10.1038/s41443-021-00439-2. Epub ahead of print. PMID: 34035467.

This work aimed to establish mechanical testing methodology and characterize pathological tissue mechanics of Peyronie’s disease. Tunica albuginea was obtained from patients (n = 5) undergoing reconstructive surgery for Peyronie’s disease, sectioned into test specimens (n = 12) and imaged with micro-computed tomography (µCT). A tensile testing protocol was developed based on similar soft tissues. Correlation of mechanical summary variables (force, displacement, stiffness, work, Young’s modulus, ultimate tensile stress, strain at ultimate tensile stress, and toughness) and µCT features were assessed. Mineralization volume was not correlated with mechanical parameters. Empirically hard tissue had higher ultimate tensile stress. Failure mechanisms and strain patterns differed between mineralized and non-mineralized specimens. Size, shape, and quantity of mineralization may be more important in determining Peyronie’s disease plaque behavior than presence of mineralization alone, and single summary variables like modulus may not fully describe mechanical behavior.

Single-cell Transcriptomics Uncover a Novel Role of Myeloid Cells and T-lymphocytes in the Fibrotic Microenvironment in Peyronie’s Disease.

Milenkovic U, Boeckx B, Lambrechts D, Janky R, Hatzichristodoulou G, van Renterghem K, Gevaert T, Cellek S, Bivalacqua TJ, De Ridder D, Albersen M. Eur Urol Focus. 2021 May 4:S2405-4569(21)00118-8. doi: 10.1016/j.euf.2021.04.012. Epub ahead of print. PMID: 33962884.

This work aimed to investigate the immunological signature of plaques from Peyronie’s disease (PD) patients using immunohistochemistry (IHC) and single-cell RNA sequencing (scRNA-Seq). Tunica albuginea biopsy was performed in patients undergoing penile surgery for either PD (n = 12) or plication or penile cancer (control, n = 6). IHC revealed the presence of myeloid dendritic cells (DCs; CD68+, TLR4+, CD206+), cytotoxic T lymphocytes (CTLs; CD3+, CD8+), and B lymphocytes (CD20+) in PD plaques, which were absent in controls. scRNA-Seq yielded results for 3312 PD and 5658 control cells. Cell clusters contained fibroblasts (COL1A2+), myofibroblasts (COL1A2+, ACTA2+), smooth muscle cells (ACTA2+, DES+), endothelial cells (VWF+), myeloid cells (CD14+), T lymphocytes (CD3D+), and neutrophils (ALPL+). Myeloid cell subclustering showed infiltration of monocyte-derived cells; control tissue contained classical DCs and resident macrophages. This data suggest that even in the chronic PD stage (painless and stable curvature) there is a sustained inflammatory reaction. While vascularisation and collagen production are elevated, the inflammation is driven by specialised monocyte-derived CTL and MAIT cells.

Oncology

Oxaliplatin, an Anticancer Agent, Causes Erectile Dysfunction in Rats due to Endothelial Dysfunction.

Kataoka T, Mori T, Suzuki J, Kawaki Y, Kito Y, Hotta Y, Kawade Y, Maeda Y, Kimura K. J Sex Med. 2021 Aug;18(8):1337-1345. doi: 10.1016/j.jsxm.2021.06.004. Epub 2021 Jul 17. PMID: 34281797.

This study aimed to investigate erectile function in an animal model after administration of the anticancer agent oxaliplatin (L-OHP). Male Wistar/ST rats were divided into 2 groups: L-OHP rats (n = 21), which were intravenously administered L-OHP (4 mg/kg; twice a week for 4 weeks), and Control rats (n = 21), which were injected with the same volume of 5% glucose solution, using the same dosing schedule. At the end of the study period, erectile function was evaluated by measuring intracavernous pressure (ICP) and mean arterial pressure (MAP) after cavernous nerve stimulation (n = 9–10). Endothelial function was evaluated with an isometric tension study using corpus cavernosum strips (n = 11). Western blot analysis was used to assess neuronal nitric oxide (nNOS) and endothelial NO synthase (eNOS) protein levels (n = 7). The L-OHP group had a significantly lower ICP:MAP ratio than the control group (P < .05). Compared to the Control group, the L-OHP group exhibited significantly lower responses to ACh and eNOS protein levels and significantly higher inflammatory biomarker levels. The results based on this animal model indicate that use of the anticancer agent L-OHP should be considered as a risk factor for ED occurring via reduction of NO bioavailability in humans; our results provide possible treatment strategies for maintaining the erectile function of cancer survivors.

Orgasm/ Sexual desire

Sexual Motivation and Sexual Reward in Male Rats are Attenuated by the Gonadotropin-Releasing Hormone Receptor Antagonist Degarelix.

Hawley WR, Kapp LE, Dingle CM, Dufala HA, Green PA, Barnes JL, Barwell JL. J Sex Med. 2021 Feb;18(2):240-255. doi: 10.1016/j.jsxm.2020.11.004. Epub 2021 Jan 6. PMID: 33419705.

The aim of this study was to examine the effects of a single administration of the gonadotropin-releasing hormone receptor antagonist, degarelix, on sexual incentive motivation (SIM), sexual reward, consummatory sexual behaviors, anxiety-like behavior, and androgen receptor signaling in male rats, and to determine if sexual stimulation attenuates the effects of degarelix on SIM. Rats treated with degarelix exhibited lower levels of SIM. In rats treated with degarelix, contact with a female immediately before SIM testing increased activity, but not SIM. Treatment with degarelix reduced the rewarding aspects of sexual behavior, as well as most aspects of copulatory ability and sexual performance.

Female sexuality

Changes of Apomorphine-Induced Vaginal Hemodynamics in an Ovariectomized Rat Model Using Near-Infrared Spectroscopic Probe.

Jeong H, Lee HS, Seong M, Baek J, Park K, Kim JG. J Sex Med. 2021 Aug.18(8):1328-1336. doi: 10.1016/j.jsxm.2021.05.012. Epub 2021 Jul 8. PMID: 34247951.

This study aimed to investigate the longitudinal changes in female sexual arousal response induced by apomorphine (APO) administration in the ovariectomized rat using near-infrared spectroscopy (NIRS) probe.

To elicit sexual arousal, APO was administered subcutaneously to animals (n = 6) before and after ovariectomy, and the changes in oxyhemoglobin (OHb), deoxyhemoglobin (RHb), total hemoglobin (THb) concentration, and temperature on the vaginal wall after APO administration were monitored bi-weekly for 8 weeks.  APO administration caused the increase of vaginal OHb and RHb concentration but a decrease in temperature. The amplitude of OHb, RHb, and THb increase induced by APO gradually decreased over 8 weeks after ovariectomy while the decrease in vaginal temperature became profound. A comparison between the parameters measured from the NIRS probe and the others (estradiol level, amount of vaginal secretion, and body weight) proved that the NIRS has the potential as a monitoring tool to evaluate female sexual arousal response.

Immunohistochemical Investigation of Autonomic and Sensory Innervation of Anterior Vaginal Wall Female Periurethral Tissue: A Study of the Surgical Field of Mid-Urethral Sling Surgery Using Cadaveric Simulation.

Giovannetti O, Tomalty D, Gaudet D, Clohosey D, Forster A, Monaghan M, Harvey MA, Johnston S, Komisaruk B, Goldstein S, Hannan J, Goldstein I, Adams MA. J Sex Med. 2021 Jul;18(7):1167-1180. doi: 10.1016/j.jsxm.2021.05.002. Epub 2021 Jun 24. PMID: 34176756.

Anterior vaginal wall-female periurethral tissue (AVW-FPT) likely contains autonomic and sensory innervation involved in the female sexual response, and injury to these nerves may result from mid-urethral sling (MUS) implantation. This study aimed to characterize, using fresh cadaveric tissue, autonomic and sensory nerves in AVW- FPT using immunohistochemistry (IHC), and to assess their proximity to an implanted MUS. AVW-FPT was excised from four fresh cadavers. IHC of AVW-FPT using protein gene product 9.5 (PGP9.5), a general nerve stain, revealed innervation throughout the region targeted by the MUS implantation. More specifically, immunoreactivity for both autonomic (tyrosine hydroxylase, TH) and sensory (Nav1.8 and S100ß) nerves were found in close proximity (<1 mm) to the implanted MUS. Combining the IHC findings with the surgical simulation of the MUS implantation revealed the potential for damage to both autonomic and sensory nerves as a direct result of the MUS procedure.

Overexpressing miR-122-5p Inhibits the Relaxation of Vaginal Smooth Muscle in Female Sexual Arousal Disorder by Targeting Vasoactive Intestinal Peptide Receptor 1.

Cong S, Gui T, Shi Q, Zhang J, Feng J, Pan L, Ma J, Zhang A. Sex Med. 2021 Aug;9(4):100390. doi: 10.1016/j.esxm.2021.100390. Epub 2021 Jul 8. PMID: 34246178; PMCID: PMC8360939.

The aim if this study was to investigate the specific function of miR-122-5p in Female sexual arousal disorder (FSAD). The authors verified that women with FSAD had higher miR-122-5p and lower vasoactive intestinal peptide receptor 1 (VIPR1) protein. Then overexpressing miR-122-5p decreased relaxation of rat vaginal smooth muscle cells (SMCs), which was manifested as a contractile morphology of cells, an increased intracellular free Ca2+ concentration, and lower cAMP concentration and PKA activity. The authors concluded thatvmiR-122-5p regulates the relaxation of vaginal SMCs in FSAD by targeting VIPR1, ulteriorly providing an underlying diagnostic and therapeutic target for FSAD.

Gender incongruence

Implications of the Estrogen Receptor Coactivators SRC1 and SRC2 in the Biological Basis of Gender Incongruence.

Ramírez KDV, Fernández R, Delgado-Zayas E, Gómez-Gil E, Esteva I, Guillamon A, Pásaro E. Sex Med. 2021 Jun;9(3):100368. doi: 10.1016/j.esxm.2021.100368. Epub 2021 May 26. PMID: 34049263; PMCID: PMC8240342.

This study aimed to to analyze the implication of the estrogen receptor coactivators SRC-1, SRC-2, and SRC-3 in the genetic basis of gender incongruence. The authors analysed 157 polymorphisms located at the estrogen receptor coactivators SRC-1, SRC-2, and SRC-3, in 94 transgender versus 94 cisgender individuals. They found significant differences in 8 polymorphisms that correspond to 5.09% of the total. Three were located in SRC-1 and 5 in SRC-2. The SRC-1 haplotypes CGA and CGG and the SRC-2 haplotypes GGTAA and GGTAG were overrepresented in the transgender population. In conclusion, the coactivators SRC-1 and SRC-2 could be considered as candidates for increasing the list of potential genes for gender incongruence.