BMP4 and GREM1 are targets of SHH signaling and downstream regulators of collagen in the penis.

BACKGROUND: Cavernous nerve (CN) injury, caused by prostatectomy and diabetes, initiates a remodeling process (smooth muscle apoptosis and increased collagen) in the corpora cavernosa of the penis of patients and animal models that is an underlying cause of erectile dysfunction (ED), and the Sonic hedgehog (SHH) pathway plays an essential role in the response of the penis to denervation, as collagen increases with SHH inhibition and decreases with SHH treatment. AIM: We examined if part of the mechanism of how SHH prevents penile remodeling and increased collagen with CN injury involves bone morphogenetic protein 4 (BMP4) and gremlin1 (GREM1) and examined the relationship between SHH, BMP4, GREM1, and collagen in penis of ED patients and rat models of CN injury, SHH inhibition, and SHH, BMP4, and GREM1 treatment. METHODS: Corpora cavernosa of Peyronie's disease (control), prostatectomy, and diabetic ED patients were obtained (N = 30). Adult Sprague Dawley rats (n = 90) underwent (1) CN crush (1-7 days) or sham surgery; (2) CN injury and BMP4, GREM1, or mouse serum albumin (control) treatment via Affi-Gel beads or peptide amphiphile (PA) for 14 days; (3) 5E1 SHH inhibitor, IgG, or phosphate-buffered saline (control) treatment for 2 to 4 days; or (4) CN crush with mouse serum albumin or SHH for 9 days. OUTCOMES: Immunohistochemical and Western analysis for BMP4 and GREM1, and collagen analysis by hydroxyproline and trichrome stain were performed. RESULTS: BMP4 and GREM1 proteins were identified in corpora cavernosa smooth muscle of prostatectomy, diabetic, and Peyronie's patients, and in rat smooth muscle, sympathetic nerve fibers, perineurium, blood vessels, and urethra. Collagen decreased 25.4% in rats with CN injury and BMP4 treatment (P = .02) and increased 61.3% with CN injury and GREM1 treatment (P = .005). Trichrome stain showed increased collagen in rats treated with GREM1. Western analysis identified increased BMP4 and GREM1 in corpora cavernosa of prostatectomy and diabetic patients, and after CN injury (1-2 days) in our rat model. Localization of BMP4 and GREM1 changed with SHH inhibition. SHH treatment increased the monomer form of BMP4 and GREM1, altering their range of signaling. CLINICAL IMPLICATIONS: A better understanding of penile remodeling and how fibrosis occurs with loss of innervation is essential for development of novel ED therapies. STRENGTHS AND LIMITATIONS: The relationship between SHH, BMP4, GREM1, and collagen is complex in the penis. CONCLUSION: BMP4 and GREM1 are downstream targets of SHH that impact collagen and may be useful in collaboration with SHH to prevent penile remodeling and ED.

Rab25 is involved in hypospadias via the ß1 integrin/EGFR pathway.

BACKGROUND: Hypospadias is a common congenital abnormality of the penile. Abnormal regulation of critical genes involved in urethral development leads to hypospadias. We used the Rab25-/- mice and foreskin fibroblasts transfected with lentivirus in vitro and in vivo to investigate the role of Rab25 in hypospadias. METHODS: The expression levels of various molecules in tissue samples and foreskin fibroblasts were confirmed using molecular biology methods (western blotting, PCR, immunohistochemistry, etc.). A scanning electron microscope (SEM) was used to visualize the external morphology of genital tubercles (GTs) of gestation day (GD) 18.5 male wild-type (WT) and Rab25-/- mice. RESULTS: An expanded distal cleft and V-shaped urethral opening were observed in GD 18.5 Rab25-/- mice. We demonstrated that Rab25 mediated hypospadias through the ß1 integrin/EGFR pathway. In addition, silencing Rab25 inhibited cell proliferation and migration and promoted apoptosis in the foreskin fibroblasts; Ki-67- and TUNEL-positive cells were mainly concentrated near the urethral seam. CONCLUSION: These findings suggest that Rab25 plays an essential role in hypospadias by activation of ß1 integrin/EGFR pathway, and Rab25 is a critical mediator of urethral seam formation in GD18.5 male fetal mice.

Methylation of eNOS in the rat penile corpus cavernosum under different pathological states and its relationship with erectile function.

BACKGROUND: It has been shown that methylation in the promoter region of eNOS can downregulate eNOS expression resulting in the endothelial dysfunction. However, it is unclear whether low androgen levels and type 1 diabetes cause ED by methylating the promoter region of eNOS in the penile corpus cavernosum. OBJECTIVE: To clarify the effects of type 1 diabetes and hypo-androgen status on the methylation level of the promoter region of the eNOS gene in penile cavernous tissue and their relationship with the erectile function. METHODS: Fifty-eight eight-week-old male Sprague-Dawley rats were randomly divided into six groups (n = 6): sham operation group, castration group, castration+testosterone (cast+T) group, normoglycemia group, diabetic group, and diabetic+methyltransferase inhibitor (5-aza-dc, 1.5 mg/kg) group. The ICPmax/MAP, serum T, the concentration of nitric oxide (NO), the expression of DNMT1, DNMT3a, DNMT3b, and eNOS, and the methylation level of the eNOS promoter region in penile corpus cavernosum of rat were examined 4 weeks after surgery in the sham-operated group, the castration group, and the castration + testosterone replacement group. Those tests were examined after 6 weeks using of methylation inhibitors in the normoglycemic group, the diabetic group, and the diabetic + methylation inhibitor group. RESULTS: ICPmax/MAP, DNMT1, DNMT3a, DNMT3b, eNOS, and NO levels were significantly lower in castrated rats than in sham and cast+T rats (P < 0.05). ICPmax/MAP, eNOS, and NO levels were lower, and DNMT1, DNMT3a, and DNMT3b expression levels were significantly increased in the diabetic group compared with the normoglycemic and diabetic+methyltransferase inhibitor groups (P < 0.05). There was no significant difference in the methylation level of the promoter region of eNOS in penile cavernous tissue of castrated rats compared with the sham group or the testosterone replacement group. The methylation level of the promoter region of eNOS in penile cavernous tissue was significantly higher in the diabetic group than in the normoglycemic group and diabetic+methyltransferase inhibitor group (P < 0.05). CONCLUSION: Although low androgen status inhibited the level of methyltransferase in rat penile cavernous tissue, did not affect the level of methylation in the promoter region of eNOS. Hyperglycemia inhibits the NO level in the penile cavernous tissue and the erectile function of rats by upregulating the methyltransferase level in the penile cavernous tissue and the methylation level in the promoter region of eNOS. Methylation inhibitors can partly improve the erectile function in type 1 diabetic rats.

Evaluation of androgen receptor markers in erectile dysfunction.

BACKGROUND: Steroid hormones, such as testosterone, play a crucial role in modulating the development of male internal and external genitalia as well as secondary sex characteristics by binding to the androgen receptor. Once bound, androgen receptor operates as an inducible transcription factor, interacting with a multitude of co-regulators to initiate various downstream signaling pathways. The androgen saturation hypothesis posits that beyond a specific threshold, androgen receptor binding and functionality remain unaltered despite an increase in serum testosterone levels. OBJECTIVES: The objective of this study was to explore the expression of these proteins in penile tissue samples from men with severe erectile dysfunction to enhance our understanding of the influence of serum testosterone on androgen receptor function. MATERIALS AND METHODS: Patients undergoing surgical management for high-grade ED at our institution were invited to participate in the study. During inflatable penile prosthesis surgery, corpus cavernosum biopsy was obtained. Protein was extracted from each sample for western blot analysis which was probed with androgen receptor, heme oxygenase, inducible nitric oxide synthase, and phosphodiesterase type 5 antibodies with GAPDH for protein normalization. RESULTS: 12 men agreed to participate in this study. Serum testosterone levels were obtained from all participants on the morning of their surgery. The median testosterone level was 300.15 ng/dL. Our findings revealed a decrease in androgen receptor and inducible nitric oxide synthase expression at serum testosterone levels below 300 ng/dL (p = 0.022, 0.03). Similarly, hemeoxygenase and phosphodiesterase type 5 expression levels were significantly lower at serum T concentrations below 200 ng/dL (p = 0.017, 0.014). DISCUSSION AND CONCLUSION: These data showed a significant decrease in the expression of proteins downstream of the androgen receptor at lower serum T levels. This suggests a potential correlation between serum T concentration and androgen receptor signaling and supports a potential saturation value between 200 and 300 ng/dL.

The Spectrum of HPV-independent Penile Intraepithelial Neoplasia: A Proposal for Subclassification.

Compared with vulva, precursor lesions of human papillomavirus (HPV)-independent invasive squamous cell carcinoma (SCC) of the penis are insufficiently characterized. We analyzed the histologic and immunohistochemical characteristics of 70 peritumoral precursor lesions and correlated them with the histology and mutational profile of the adjacent HPV-negative invasive penile SCC. Atypical basal keratinocyte proliferation with variously elongated epithelial rete with premature squamatiziation, but regular superficial cornification, termed differentiated penile intraepithelial neoplasia (d-PeIN), were identified adjacent to 42/70 (60%) SCC (36/42 keratinizing ( P <0.001); 3 papillary, and 1 each verrucous, clear cell, sarcomatoid SCC). d-PeIN were associated with chronic inflammatory dermatoses (32/42; P <0.001), p53 overexpression (26/42; P <0.001), and hotspot mutations in TP53 (32/42; P <0.001), CDKN2A (26/42; P <0.001) or both (21/42; P =0.003) in the adjacent SCC. Cytoplasmic p16 ink4a overexpression in 5/42 d-PeIN correlated with CDKN2A missense mutations in the adjacent SCC. In all, 21/70 (30%) cornified verrucous or glycogenated verruciform precursors with minimal atypia and wild-type p53 (18/21; P <0.001) occurred adjacent to verrucous or papillary SCC (17/21; P <0.001) and keratinizing (4/21) SCC, which harbored mutations in HRAS and/or PIK3CA (12/21; P <0.004). Undifferentiated p16 ink4a -negative full-thickness precursors were identified in 7/70 (10%) SCC. Four histologically different HPV-independent penile precursor lesions can be assigned to 2 major genetic/biological pathways with characteristic highly differentiated precursors requiring different clinical management decisions. These include d-PeIN in chronic inflammatory dermatoses, with p53 overexpression and TP53/CDKN2A mutations, and the p53 wild-type verrucous and verruciform precursors unassociated with dermatoses, but with mutations in oncogenes PIK3CA and HRAS .

Effects of transplantation of umbilical cord blood mononuclear cells into the scrotum on sexual function in elderly mice.

Aim: This study investigated the effect of allografting umbilical cord blood mononuclear cells (UCBMCs) into the scrotum on sexual function in male elderly mice. Methods: UCBMCs were injected once into the scrotal sheath cavity of elderly mice. Results: The transplanted UCBMCs survived in the scrotal sheath cavity for 1 month. The mice had significantly increased blood testosterone concentrations, cyclic guanosine monophosphate (cGMP) levels and total nitric oxide synthase (T-NOS) activity in the corpus cavernosum and an increase in the number of mouse matings within 30 min (all p = 0.000). Conclusion: Scrotum-implanted UCBMCs improve the sexual function of male elderly mice through testosterone production and the NOS/cGMP pathway, which may provide an innovative transplantation approach for the treatment of erectile dysfunction.

Molecular Mechanisms and Risk Factors Related to the Pathogenesis of Peyronie's Disease.

Peyronie's disease (PD) is a benign condition caused by plaque formation on the tunica albuginea of the penis. It is associated with penile pain, curvature, and shortening, and contributes to erectile dysfunction, which worsens patient quality of life. In recent years, research into understanding of the detailed mechanisms and risk factors involved in the development of PD has been increasing. In this review, the pathological mechanisms and several closely related signaling pathways, including TGF-ß, WNT/ß-catenin, Hedgehog, YAP/TAZ, MAPK, ROCK, and PI3K/AKT, are described. Findings regarding cross-talk among these pathways are then discussed to elucidate the complicated cascade behind tunica albuginea fibrosis. Finally, various risk factors including the genes involved in the development of PD are presented and their association with the disease summarized. The purpose of this review is to provide a better understanding regarding the involvement of risk factors in the molecular mechanisms associated with PD pathogenesis, as well as to provide insight into disease prevention and novel therapeutic interventions.

Heterogeneity of fibroblasts is a hallmark of age-associated erectile dysfunction.

BACKGROUND: The prevalence of age-associated erectile dysfunction (ED) increases pronouncedly with age. However, the cellular composition and transcriptomic changes of aging penile corpus cavernosum remain largely unclear. METHODS: Herein, we performed single cell sequencing penile corpus cavernosum from five young with normal erectile response and five old rats with ED. RESULTS: Clustering analysis identified 19 cell types, such as fibroblasts, myofibroblasts and immune cells. We next revealed their transcriptomic alterations and investigated novel subpopulations of major cell types. Among them, fibroblasts possessed the largest cell number and showed apparent heterogeneity. By performing single-cell entropy analysis on fibroblasts, we observed the age-associated decrease of entropy, and aged fibroblasts were found to adopt senescent secretory phenotype, as evidenced by the high expression of genes associated with the senescence-associated secretory phenotype (SASP). Finally, we constructed a comprehensive intercellular communication network and highlighted key mediators of crosstalk between fibroblasts and other cell types. CONCLUSIONS: We plotted a cellular atlas of aging cells within penile corpus cavernosum, especially fibroblasts. Our work will deepen the understanding of the heterogeneity among certain cell types within aged penile corpus cavernosum, which will generate positive effects on the future treatment of age-associated ED.

Cytoskeletal protein SPTA1 mediating the decrease in erectile function induced by high-fat diet via Hippo signaling pathway.

BACKGROUND: The mechanism of high-fat diet (HFD)-induced decrease in erectile function has not been elucidated, and in previous studies, spectrin alpha, erythrocytic 1 (SPTA1) is a cytoskeletal protein that regulates cellular function, which belongs to a family of proteins that can affect cell and tissue growth and development by regulating YAP, an effector on the Hippo signaling pathway, but its particular role has not been elucidated. OBJECTIVE: To explore the role of SPTA1 in the abnormality of erectile function induced by HFD. METHODS: We analyzed the penile tissues of mice on normal diet and HFD by transcriptomics and screened for differentially expressed genes, further identified closely related target genes in rat penile tissues, and verified target gene expression in in vitro construction of high-glucose (HG)-treated corpus cavernosum endothelial cells (CCECs) and corpus cavernosum smooth muscle cells (CCSMCs) models. The distribution of target genes in various cell populations in penile tissues was retrieved by single-cell sequencing Male Health Atlas database. Moreover, interfering with target genes was further applied to explore the mechanisms involved in erectile function decline. RESULTS: Transcriptomic analysis screened out down-regulated differential gene SPTA1; Western blot and immunohistochemistry results showed that SPTA1 expression significantly decreased in the penile tissues of Sprague-Dawley (SD) rats in the HFD group. Immunofluorescence staining showed a positive expression of CD31 and VWF in CCECs and a positive expression of α-SMA in CCSMCs. The expression level of SPTA1 protein significantly decreased in the HG group of CCECs and CCSMCs. The expression of SPTA1 mRNA significantly decreased in CCSMCs while significantly increased in CCECs. SPTA1 may have various expression patterns and biological functions in different cell populations. Real-time quantitative PCR results showed that the siSPTA1 transfected in CCSMCs had a significant interference effect compared with the control siNC. Transfection of siSPTA1 into CCSMCs resulted in the significant down-regulation of mRNA and protein expression of eNOS, and significant up-regulation of YAP, Caspase-1, GSDMD, GSDMD-N IL-18, and IL-1ß protein expression levels. The expression level of CCSMCs contractile-type protein α-SMA was significantly down-regulated. CONCLUSIONS: The down-regulation of SPTA1 in SD rats fed with HFD may induce cell pyroptosis and lead to the decrease of erectile function by activating the Hippo pathway; these findings may provide new therapeutic targets for improving erectile function.

IGFBP5 antisense and short hairpin RNA (shRNA) constructs improve erectile function by inducing cavernosum angiogenesis in diabetic mice.

BACKGROUND: The incidence of diabetic erectile dysfunction (ED) is rapidly increasing, and due to the severe angiopathy caused by diabetes, current drugs are ineffective at treating ED. Insulin-like growth factor-binding protein 5 (IGFBP5) promotes cell death and induces apoptosis in various cell types. OBJECTIVES: To evaluate the effectiveness of IGFBP5 knockdown in improving erectile function in diabetic mice. MATERIALS AND METHODS: Diabetes was induced by injecting streptozotocin (STZ) intraperitoneally into male 8-week-old C57BL/6 mice. Eight weeks after diabetes induction, mice were divided into four groups: a nondiabetic control group and three STZ-induced diabetic mice groups, which were administered intracavernous injections of phosphate buffered saline, scrambled control shRNA, or shRNA targeting mouse IGFBP5 (shIGFBP5) lentivirus particles. Two weeks later, we measured erectile function by electrically stimulating the bilateral cavernous nerve. To mimic diabetic angiopathy, primary cavernous endothelial cells (MCECs) from healthy mice were cultured and treated with glucose. RESULTS: IGFBP5 expression in MCECs or cavernous tissues were significantly increased under diabetic conditions, and knockdown of IGFBP5 induced MCECs angiogenic activity under high-glucose conditions. STZ-induced diabetic mice had reduced erectile function, but shIGFBP5 treatment resulted in significant improvements (to 90% of the nondiabetic control group level). Furthermore, in diabetic mice, numbers of cavernous endothelial cells, pericytes, and neuronal cells were increased by shIGFBP5 treatment, which also increased eNOS Ser1177 phosphorylation, decreased permeability and apoptosis of cavernous endothelial cells. In addition, IGFBP5 was found to mediate the AKT, ERK, p38 signaling pathways. DISCUSSION AND CONCLUSION: Knockdown of IGFBP5 improved erectile function in diabetic mice by promoting cell proliferation and reducing apoptosis and permeability. Local inhibition of IGFBP5 expression may provide a new treatment strategy for diabetic ED and other ischemic vascular or neurological diseases.

Saxagliptin alleviates erectile dysfunction through increasing stromal cell-derived factor-1 in diabetes mellitus.

BACKGROUND: Diabetes mellitus-induced erectile dysfunction (DMED) is one of the complications of diabetes and has a poor response to phosphodiesterase type 5 inhibitor, the first-line treatment for ED. Saxagliptin (Sax), a dipeptidyl peptidase-4 inhibitor (DPP-4i), has been officially used in the treatment of type 2 diabetes. Stromal cell-derived factor-1 (SDF-1) is one of the important substrates of DPP-4, and has been proven to be beneficial for several DM complications. However, it is unknown whether Sax contributes to the management of DMED. OBJECTIVES: To explore the effect and possible underlying mechanisms of Sax in the treatment of DMED. METHODS: The model of DM was established by intraperitoneal injection of streptozotocin. All rats were divided into three groups (n = 8 per group): control group, DMED group and DMED+Sax group. In cellular experiments, the corpus cavernosum smooth muscle cells (CCSMCs) were exposed to high glucose (HG), and treated with Sax and AMD3100 (SDF-1 receptor inhibitor). The penile tissue and CCSMCs were harvested for detection. RESULTS: We found that erectile function was impaired in DMED rats compared with the control group, which was partially relieved by Sax. Decreased expression of DPP-4 and increased level of SDF-1 were also observed in DMED+Sax group, together with elevation of PI3K/AKT pathway and inhibition of endothelial dysfunction, oxidative stress and apoptosis in corpus cavernosum. Moreover, Sax could also regulate oxidative stress and apoptosis in CCSMCs under HG condition, which was blocked in part by AMD3100. CONCLUSION: Sax could alleviate DMED through increasing SDF-1 and PI3K/AKT pathway, in company with moderation of endothelial dysfunction, oxidative stress and apoptosis. Our findings indicated that DPP-4 is may be beneficial to the management of DMED.

Tumor lesions of penis and scrotum according to WHO classification 2022.

Similarly to testicular tumors, key changes on penile and scrotal neoplasia were incorporated into WHO classification 2016. Therein, penile squamous cell carcinomas were divided into two groups based on the pathogenesis, namely HPV-associated and HPV-independent. This remains unchanged in WHO classification 2022. For those carcinomas where HPV status can not be determined, a category of squamous cell carcinoma NOS was added. Variants of squamous cell carcinoma, namely basaloid, papillary-basaloid, warty, warty-basaloid, clear cell and lymphoepithelioma-like carcinomas are not recognized as distinctive variants of HPV-associated group anymore. Similarly, squamous cell carcinoma, usual type, pseudohyperplastic, pseudoglandular, verrucous carcinoma, carcinoma cunniculatum, papillary, adenosquamous, sarcomatoid and mixed carcinoma are no more not recognized as distinctive variants of HPV-independent carcinomas. Instead, these variants are now called subtypes. Some previously distinct subtypes now belong to the morphological spectrum of other subtypes. Basaloid-papillary subtype belongs to basaloid squamous cell carcinoma and carcinoma cunniculatum is currently recognized as morphological variation of verrucous carcinoma. Pseudohyperplastic and mixed subtypes were removed from the classification. Adenosquamous carcinoma is currently termed adenosquamous and mucoepidermoid carcinoma and represents distinct entity. Precursor lesions of squamous cell carcinoma underwent substantial modifications in the WHO classification 2016 as well, and remain unchanged in WHO classification 2022. Terminology for HPV - induced lesions have been unified to low grade squamous intraepithelial lesions (LSIL) and high grade squamous intraepithelial lesions (HSIL). This classification applies to the whole anogenital area, including penis, anus, perianal region, vulva, vagina and uterine cervix. LSIL is further divided to condyloma accuminatum and (penile) intraepithelial neoplasia grade 1 (PeIN1), HSIL is divided to PeIN2 and PeIN3. Penile HPV-independent precursor lesions are named differrentiated penile intraepitelial neoplasia (dPeIN) and are identical to analogous lesions on vulva.

Silencing myostatin increases area fraction of smooth muscle in the corpus cavernosum of pigs.

Myostatin (MSTN), an inhibitor of skeletal muscle growth, is also expressed in penile smooth muscle; however, it is unclear whether MSTN plays an inhibitory role in penile smooth muscle growth. We investigated the role of MSTN in the smooth muscle of the penile corpus cavernosum of pigs using MSTN homozygous mutant knockout (KO) and wild type (WT) pigs (n = 4 in each group). The mean of area fraction (%) of smooth muscle in the penile corpus cavernosum was 65.9 % ± 1.79 in the KO and approximately 41.7 % ± 5.39 in the WT (P < 0.001). KO pigs showed significantly increased expression of smooth muscle-specific genes, including smooth muscle protein 22 (TAGLN) (6.62-fold), smooth muscle myosin heavy chain (MYH11) (2.41-fold), myocardin (MYOCD) (3.05-fold), and serum response factor (SRF) (4.95-fold), and decreased expression of vimentin (VIM) (1.36-fold). Immunofluorescence staining and Western blotting showed smooth muscle-specific expression of α-smooth muscle actin (SMA) and calponin was higher in KO pigs (P < 0.05) than in WT pigs. KO pigs had less fat deposition inside the corpus cavernosum, and showed downregulation of adiponectin (ADIPOQ) and fatty acid synthase (FASN) (2.5-fold and 1.9-fold loss, respectively). In vitro experiments showed MSTN interference promoted corporal smooth muscle cell growth and expression of smooth muscle-specific markers, whereas it downregulated the expression of fat-specific genes, ADIPOQ and FASN. MSTN inhibition could promote smooth muscle growth and decrease fat deposition in the corpus cavernosum. MSTN, thus, could be a possible target for the treatment of smooth muscle dystrophy-related disorders such as erectile dysfunction.

Micro RNA 200a contributes to the smooth muscle cells growth in aged-related erectile dysfunction via regulating Rho/ROCK pathway.

Aged-related erectile dysfunction (A-ED) is generally regarded as degeneration of penile erectile tissue due to age, male hormone deficiency and concomitant cardiovascular disease. Current pathological studies of A-ED are still limited. In this study, aged rats were divided into AE group (aged rats with ED) and YN group (young normal rats) for evaluating the roles of miRNA-200a and RhoA/ROCK signalling pathway in A-ED. Apo-morphine test, ICP measurement and pathological results were compared between these two groups. After transfection of miRNA-200a into Corpus cavernosum smooth muscle cells (CCSMCs), the expression of miRNA-200a, RhoA, ROCK1 and ROCK2 in the AE group were significantly increased. Additionally, miRNA-200a, RhoA, ROCK1 and ROCK2 were upregulated at a high level after transfecting the miRNA-200a mimics. Therefore, we speculated that miRNA-200a is a positive regulator, which may inhibit the growth of CCSMCs by activating the Rho/ROCK pathway in vitro.

Low androgen level impairs erectile function of rat by regulating the Ng/CaN/AKT/eNOS pathway in penile corpus cavernosum.

BACKGROUND: The mechanism by which low androgen status inhibit erectile function has not yet been clearly elucidated. Neurogranin (Ng) is a Ca2+ -sensitive calmodulin binding protein that is expressed in endothelial cells and regulates eNOS function. OBJECTIVES: To investigate whether low androgen status inhibit erectile function by regulating the Ng/CaN/AKT/eNOS pathway in the penile cavernous tissue of rats. MATERIALS AND METHODS: Thirty-six 8-week-old male Sprague-Dawley rats were randomly divided into six groups as follows (n = 6): 4-week control group (4w-control), 4-week castration group (4w-cast), 4-week castration+testosterone replacement group (4w-cast+T), 8-week control group (8w-control), 8-week castration group (8w-cast), and 8-week castration+testosterone replacement group (8w-cast+T). Four weeks and eight weeks after surgery, the ratio of the maximum intracavernous pressure/mean arterial pressure (ICPmax/MAP) was examined. The level of NO and the expression of Ng, calcineurin (CaN), AKT, p-AKT(S473), eNOS, and p-eNOS(Ser1177) in the penile cavernous tissue of each group were determined. RESULTS: Ng and CaN were mainly expressed in the membrane and cytoplasm of endothelial cells and smooth muscle cells in the penile cavernous tissue of rats. The ICPmax/MAP and the concentration of NO in the cast group were significantly lower than those in the control group and cast+T replacement group (p < 0.01). The expression of Ng and the ratios of p-AKT/AKT and p-eNOS/eNOS in the penile cavernous tissue of rats in the cast group were significantly lower than those in the control group and cast+T replacement group (p < 0.01). The expression of CaN in the penile cavernous tissue of rats in the cast group was significantly increased compared with that in the control group and the cast+T replacement group (p < 0.01). CONCLUSION: Inhibiting the expression of Ng and subsequently upregulating the expression of CaN in the rat penile cavernous tissue was one of the upstream mechanisms of low androgen status inhibiting erectile function by inhibiting the AKT/eNOS signaling pathway.

Erectile dysfunction in hypospadiac male adult rats induced by maternal exposure to di-n-butyl phthalate.

For the treatment of hypospadias, a significant number of studies focus on penile reconstruction. However, scant attention is given to sexual behavior of hypospadiac patients and underlying mechanisms. A rat model of hypospadias was constructed by maternal di-n-butyl phthalate (DBP) exposure (800 mg/kg/day by gavage during gestational days 14-18). Ten-week-old male rats with hypospadias undertook significantly decreased penis/body weight ratio, reduced testis/body weight ratio, lower serum testosterone level and thinner myelin sheath thickness of cavernosum nerves. Meanwhile, erectile dysfunction (ED) was found in hypospadiac rats, which showed significant increases in transforming growth factor-ß1 (TGF-ß1) protein expression and decreases in the expression of alpha smooth muscle actin (α-SMA) protein, neuronal and endothelial nitric oxide synthase protein (nNOS and eNOS). In addition, phosphorylated protein kinase B/protein kinase B (pAkt/Akt) ratios were remarkably lower, but the Bcl-2-associated X protein (Bax)/Bcl-2 ratios, caspase-3 protein expression, nuclear factor erythroid 2-related factor 2/ Kelch-like ECH-associated protein 1 (Nrf2/Keap-1) ratios, NAD(P)H dehydrogenase quinone 1(NQO1) protein expression and heme oxygenase-1 (HO-1) protein expression were higher in the hypospadias groups than the control group. Notably, ED is comorbid with hypospadias in cases. Penile fibrosis, testosterone deficiency, and endothelial dysfunction lead to ED in hypospadias induced by DBP eventually, which might be explained by activating Akt/Bad/Bax/caspase-3 pathway, Nrf2/Keap-1 pathway and suppressing NOS/cGMP pathway in penis.

A3 adenosine receptor allosteric modulator CF602 reverses erectile dysfunction in a diabetic rat model.

Adenosine plays a major role in erection by binding to its receptors and activating pathways resulting in increased arterial blood flow and intracavernosal pressure (ICP). CF602, an allosteric modulator of the A3 adenosine receptor (A3AR), increases the binding affinity of the endogenous adenosine to the receptor. We examined the effect of CF602 on resolving erectile dysfunction (ED) in a diabetic ED rat model (streptozotocin-induced diabetic rats that were screened for ED using the apomorphine test). ED was assessed by measuring ICP and main arterial pressure (MAP) during electrostimulation of the cavernosal nerve. A single dose of CF602 or placebo was applied either topically (100 µl from a 100 nM or 500 nM solution) or orally (100, 200 or 500 µg/kg) prior to erectile function assessment. A significant dose-dependent improvement in the ICP:MAP ratio without a change in MAP was recorded with the topical and oral CF602 treatments. A significant increase in smooth muscle:collagen ratio, vascular endothelial growth factor and endothelial nitric oxide synthase was also observed in both administration modes. In conclusion, topical and oral treatment with CF602 significantly improved erectile function, supporting its further evaluation as a treatment for ED.

Icariin inhibits the formation of mitochondria-associated membranes (MAMs) and improves erectile function in rats treated with prostate radiation.

BACKGROUND: Erectile function is usually impaired after radiation therapy in prostate cancer patients. eNOS is a key enzyme in the process of erection. Mitochondria-associated membranes (MAMs) are closely contacted with the production and bioactivity of eNOS. OBJECTIVE: To study the mechanism of icariin improves the erectile function of rats treated with prostate radiation by controling the expression of MAMs in penile corpus cavernosum. METHODS: Twenty 8-week-old healthy male SD rats were randomized to four groups: control group, radiation therapy (RT) group, icariin (10 mg/kg/d gavage) group, and RT + icariin (10 mg/kg/d gavage) group (n = 5). In RT group and RT + icariin group, rats were irradiated with X-rays to the prostate region (total dose 37.5 gray; 7.5 gray/day for 5 days). The maximum intracavernous pressure/mean arterial pressure (ICPmax/MAP), NO concentration and the level of IP3 R1, PACS2, FACL4, nNOS, p-eNOS, and eNOS in rats' penile cavernous tissue was determined 9 weeks after radiation therapy. RESULTS: Compared with the control group and the RT + icariin group, the ICPmax/MAP of the RT group was remarkably reduced (p < 0.05). The levels of p-eNOS/eNOS, nNOS and the concentration of NO in the penile cavernous tissue of the penis in the RT group were remarkably decreased compared to the control group and the RT + icariin group (p < 0.05). The levels of IP3 R1, PACS2, and FACL4 in penile cavernous tissue of the RT group were significantly higher than those in the control group and the RT + icariin group (p < 0.05). CONCLUSIONS: After prostate X-ray radiotherapy in rats, the formation of MAMs may be increased by increased expression of IP3 R1, PACS2, and FACL4 in penile cavernous tissue, resulting in impaired erectile function. Icariin might increase p-eNOS/eNOS and improve erectile function in rats after prostate radiotherapy by inhibiting the expression of IP3 R1, PACS2, and FACL4.

Testosterone Deficiency in Sickle Cell Disease: Recognition and Remediation.

Hypogonadism is common in men with sickle cell disease (SCD) with prevalence rates as high as 25%. Testicular failure (primary hypogonadism) is established as the principal cause for this hormonal abnormality, although secondary hypogonadism and compensated hypogonadism have also been observed. The underlying mechanism for primary hypogonadism was elucidated in a mouse model of SCD, and involves increased NADPH oxidase-derived oxidative stress in the testis, which reduces protein expression of a steroidogenic acute regulatory protein and cholesterol transport to the mitochondria in Leydig cells. In all men including those with SCD, hypogonadism affects physical growth and development, cognition and mental health, sexual function, as well as fertility. However, it is not understood whether declines in physical, psychological, and social domains of health in SCD patients are related to low testosterone, or are consequences of other abnormalities of SCD. Priapism is one of only a few complications of SCD that has been studied in the context of hypogonadism. In this pathologic condition of prolonged penile erection in the absence of sexual excitement or stimulation, hypogonadism exacerbates already impaired endothelial nitric oxide synthase/cGMP/phosphodiesterase-5 molecular signaling in the penis. While exogenous testosterone alleviates priapism, it disadvantageously decreases intratesticular testosterone production. In contrast to treatment with exogenous testosterone, a novel approach is to target the mechanisms of testosterone deficiency in the SCD testis to drive endogenous testosterone production, which potentially decreases further oxidative stress and damage in the testis, and preserves sperm quality. Stimulation of translocator protein within the transduceosome of the testis of SCD mice reverses both hypogonadism and priapism, without affecting intratesticular testosterone production and consequently fertility. Ongoing research is needed to define and develop therapies that restore endogenous testosterone production in a physiologic, mechanism-specific fashion without affecting fertility in SCD men.