Corpus Cavernosum Research Articles

(055) LRRC8A-VRAC Controls Superoxide Anion Flux in Diabetic Vasculogenic Erectile Dysfunction

Abstract Introduction Erectile dysfunction (ED) may be an early marker for cardiovascular diseases, and it is often associated with an hypercontractility of the corpus cavernosum (CC) as a consequence of increased reactive oxygen species (ROS), which favors the flaccid state of the penis. Leucine Rich Repeat Containing 8 (LRRC8A) Volume Regulated Anion Channels (VRACs) regulates Nox1 and modulates the extracellular production of superoxide anion (O2•-). Downregulation of LRRC8A is associated with decreased production of O2•- and we have demonstrated improved relaxation and reduced contraction of the pudendal artery in LRRC8A knockout mice. Objective We hypothesized that the role of LRRC8A in contractile responses to phenylephrine (PE) and electrical field stimulation (EFS) in the CC of diabetic mice would be exaggerated compared to that in normal mice. Methods To test this hypothesis, the CC of diabetic (dbdb-/-) mice was mounted in a myograph, and contraction elicited by PE or EFS was performed in the presence of apocynin (non-selective NOX inhibitor), GKT137831 (NOX1/4 inhibitor) and montelukast (LRRC8A inhibitor). In LRRC8A KO dbdb-/- mice, contractions to PE and EFS were obtained in the absence or in the presence of GKT137831. Results In the CC, the maximal contraction to PE was increased in diabetic animals, and in the presence of 3 mM of apocynin, the contractile response was markedly diminished in both control and diabetic mice. The LRRC8A inhibitor, montelukast, significantly reduced PE-induced contraction of the CC reaching maximal contraction of 69 + 7% and 65 + 10% in the control and diabetic group, respectively, compared to the contraction in the absence of the inhibitor. In the presence of the Nox1/Nox4 inhibitor, GKT137831, the contraction elicited by PE was reduced only in the diabetic group (68 + 9% of the maximal contraction), whereas in the control group this reduction was not significant (82 + 14% of the PE-maximal contraction). In the LRRC8A KO dbdb-/- mice, the contraction to EFS was similar to dbdb-/-, however, GKT137831 reduced the contraction to EFS with lesser magnitude of inhibition in the LRRC8A KO dbdb-/- mice (35% of inhibition) compared to dbdb-/- mice (50% of inhibition), suggesting that the participation of O2•- in the contractile response was reduced by the lack of functional LRRC8A. Conclusions LRRC8A modulates the contractile response of the CC induced by α-adrenergic stimulation and in diabetes, this may be associated with O2•- production, which plays a role in the development of ED. Inhibition of LRRC8A may be a therapeutic target to prevent hypercontractility of arteries and CC in vasculogenic ED. Disclosure No.

(250) NLRP3 Inflammasome Might Contribute to Erectile Dysfunction Induced by Chronic Unpredictable Stress in Male Mice

Abstract Introduction Introduction: The association of stress with erectile dysfunction (ED) is well known, however, it is not clear whether psychological stressors affect the vasculature and the erectile tissue in a manner that could contribute to a vasculogenic erectile dysfunction. Besides hormonal changes, cellular damage induced by stress could lead to the activation of the NLRP3, to increase production of cytokines associated with ED. In this study, we aimed to evaluate the reactivity of the corpus cavernosum and pudendal artery of male mice undergoing chronic unpredictable stress (CUS). Objective Objective: We hypothesize that CUS leads to mitochondrial damage and activates the NLRP3 inflammasome leading to impaired reactivity of the pudendal artery and corpus cavernosum which might cause erectile dysfunction. Methods Methods: Male C57Bl/6 mice were submitted to 28 days of chronic unpredictable stress (CUS). The pudendal artery and corpus cavernosum were removed and mounted in a myograph to evaluate reactivity. Tissues were kept in physiological salt solution at 37°C, constantly aerated with 95%O2/5%CO2 and concentration-response curves to acetylcholine (ACh; 1 nM – 30 uM) and phenylephrine (PE; 1 nM – 30 uM) were obtained. Using non-linear regression, we obtained the maximal response (Emax) and potency (pEC50) of ACh and PE. Expression of NLRP3, pro-caspase1 and caspase1 were measured in arteries by Western blot. Data are expressed as mean ± S.E.M. P<0.05 was considered statistically different. Results Results: CUS led to a significant decrease in the maximal relaxation induced by acetylcholine in the pudendal artery (Non-CUS: 96 ± 3% vs CUS: 84 ± 7%, n=6 and 7, respectively) and in the corpus cavernosum (Non-CUS: 88 ± 4% vs CUS: 75 ± 4%, n=7 each group) as well as an impaired contraction to PE in the corpus cavernosum (non-CUS: 1.72 ± 0.17% vs CUS: 1.07 ± 0.15%, n= 7 each group). In arteries, there were no differences in the expression of NLRP3, however, the ratio of caspase1/pro-caspase-1 was increased in CUS, suggesting that CUS increases the NLRP3 inflammasome pathway. Taken together, our data suggest that CUS led to an activation of the NLRP3 inflammasome pathway, and impaired the relaxation of the pudendal artery and corpus cavernosum by a mechanism that might be associated with decreased nitric oxide bioavailability (endothelium-dependent relaxation), whereas impaired contraction might be associated with desensitization of alpha-adrenergic receptors in response to stress. Conclusions Conclusion: Our findings demonstrate that stress impairs the reactivity of the corpus cavernosum and pudendal artery likely associated with the activation of NLRP3 inflammasome, which might play a role in the development of erectile dysfunction in stressed males. Disclosure No.

(062) The Physiological Health of the Penile Fibro-Vascular Assembly Requires the Integrity of Ten Fibro-ligaments in the Human Penis

Abstract Introduction Although the human penis has existed on earth for 3000 centuries and extensive studies have been conducted for many recent centuries, there is still room for improvement, particularly in the fibro-ligaments' role in maintaining physiological sexual health. Thus far, there needs to be more interpretation concerning these ligaments. Objective We aimed to explore the penile fibrous ligaments thoroughly to fill this research gap. Methods We excluded cadaveric penises that had both sides of the corpora cavernosa (CC) and corpus spongiosum (CS) damaged. However, penises with one undamaged side of the CC, including the Colles' fascia and the corpus spongiosum, were included. A total of 15 out of 46 penises were meticulously examined. Dissection findings were supplemented with 101 cadaveric photos and data from 263 penile vascular surgeries, 11 CT imaging scans, 8 MRI imaging scans, eight hypospadias surgeries, and eight penile elongation surgeries performed elsewhere internationally. Results Bilaterally, the penile CC is primarily anchored to the pelvis wall through the unilateral cavernosal ligament bilaterally (CL=2), while the CS is connected to the urinary sphincter. The suspensory, fundiform, and arcuate pubic ligament (two anatomically and one functionally) assist in stabilizing and holding the penile shaft to the pelvic wall. Distally, a distal ligament (DL=1) and spongiosal ligament (SL=1) extend the CC and CS to the glans penis and frenulum, ensuring urethra patency when required. The CC is encircled by a bi-layered tunica consisting of a 360° inner circular tunica and a 300° outer longitudinal coat. The ischiocavernosus muscle wraps around the penile crus and envelops the CL connecting to the ischial tuberosity. The CS is partially secured by the bulbospongiosus muscle proximally and receives the SL distally. The entire penis interconnects with the skeletal muscle of the urogenital diaphragm eventually. Conclusions The physiologically sexual health of the human penis's hydraulic system relies on the integrity of ten anatomically and six functionally fibro-muscular ligaments. Disclosure No.

(247) A Rat Model for Bipolar Androgen Therapy is Evaluated for Its Effects on Erectile Dysfunction after Castration

Abstract Introduction Prostate cancer (PCa), an androgen-dependent tumor and one of the most prevalent cancers in males, has traditionally been treated with androgen suppression. In recent years, bipolar androgen treatment (BAT) has emerged as a potential therapeutic approach for men with metastatic castrate-resistant PCa. The control of testosterone (T) between castration and supraphysiological levels inhibits the proliferation of cancer cells and slows the progression of cancer. Furthermore, while there has been prior research between T and erectile function, there is no evidence linking BAT and erectile dysfunction (ED). Objective The purpose of the current investigation was to determine if BAT therapy was effective in treating ED in a castration-prone rat model. Methods Sprague-Dawley rats (n=30) were randomly divided into four groups: 1) Control, 2) Control rats-received BAT treatment, 3) castrated Rats, and 4) castrated rats-received BAT treatment. The rats were castrated by making bilateral scrotal incisions. A subcutaneous injection of testosterone propionate (250 mg/kg/week, intramuscular) was administered four weeks following castration. Four weeks after the initial dose, the second dose of the medication was given in the same manner. By stimulating the cavernous nerve, the intracavernosal pressure (ICP) to mean arterial pressure (MAP) ratio and total ICP were determined. Corpus cavernosum (CC) strips were used as in vitro preparations for evaluating the relaxant and contractile responses. Nitric oxide synthase (nNOS) and endothelial NOS (eNOS) protein expression was analyzed using Western blotting. Using Masson trichrome staining, the location of the smooth muscle in relation to the collagen was identified. Results Castrated rats' prostate weight was reduced when compared to uncastrated rats (P< 0.001). Compared to controls and castrated rats, BAT marginally boosted prostate weight reduction. The ICP/MAP ratio and total ICP for 7.5 V were lowest in castrated rats (P< 0.001 vs. controls). BAT enhanced ICP/MAP and total ICP responses (P<0.01 vs. castrated rats). In vitro, endothelium-dependent acetylcholine-induced relaxation at 1 nM (P 0.05 vs controls), endothelium-independent sodium nitroprusside-induced relaxation at 1 nM (P 0.01 vs controls), electrical field stimulation-induced relaxant response at 20 Hz (P<0.05 vs. controls) and sildenafil-induced relaxation at 10 M (P 0.05 vs controls) were all reduced in the CC strips from the castrated group. Additionally, the castrated group showed increased neurogenic contractile response at 40 Hz and the contractile response to phenylephrine at 1 mM (P 0.001 vs. controls). The variations in the relaxation and contractile responses were returned by BAT. The smooth muscle cell-to-collagen ratio and nNOS and eNOS protein expression were both markedly reduced in castrated rats, though BAT reversed these modifications. Conclusions The results of the study show that BAT improves neurogenic relaxation, endothelium relaxation, sildenafil-induced relaxing of the CC, and changes in penile morphology after castration. BAT might be a cutting-edge therapeutic approach for patients with castration-resistant prostate cancer who have an ED route. Disclosure No.

(054) Erectile Dysfunction in Young Adulthood as a Consequence of Early Childhood Obesity

Abstract Introduction Childhood obesity is a worrisome health concern for children and teenagers, as it can contribute to several health issues in adulthood, including diabetes, high blood pressure, and high cholesterol. These conditions have been associated with sexual dysfunction. However, the precise impact of early childhood obesity on erectile function in adult males remains uncertain. Objective We hypothesized that overfeeding during early childhood can have lasting effects on body fat distribution, blood pressure, and erectile function in young adult males. Methods On postnatal day (PND 1), Wistar rats were separated into two groups: normal litter (NL) with 10 pups per dam, or small litter (SL) with 3 pups per dam. Male rats (n = 8-10 per group) were then assessed at two different time points: during the prepubertal stage (PND 40) and in adulthood (PND 120). Erectile function was assessed only after sexual maturation (i.e., on PND 120). Body weight, retroperitoneal and perigonadal adipose tissue (fat pad weight/100g of the body) were evaluated. The mean blood pressure (MBP) was recorded in conscious rats using the indirect tail-cuff method. Following euthanasia at PND 120, the corpus cavernosum was removed to perform functional studies using a strip myograph. Contractile and relaxation responses were evaluated by electrical field stimulation (EFS) and concentration-response curves (CRC) to phenylephrine [Phe, 1nM-30μM, millinewton (mN)] or acetylcholine (Ach 1nM-30μM, % relaxation) were performed. Results At the prepubertal stage, SL rats had higher body weight (NL 149±3 vs. SL 186±5, g, p<0.05), and increased retroperitoneal (NL 0.17±0.01 vs. SL 0.32±0.03, g, p<0.05) and perigonadal (NL 0.38± 0.02 vs. SL 0.45±0.03, g, p<0.05) adipose tissue. At PND 120, SL group presented increased body weight (NL 534±13vs. SL 631.6±10, g/100g, p<0.05), retroperitoneal (NL 1.31±0.11vs. SL 1.82±0.14, g/100g, p<0.05) and perigonadal (NL1.74±0.10vs. SL 2.18±0.15, g/100g, p<0.05) adipose tissue when compared with NL group. Moreover, SL rats presented increased MBP (NL 114.9±0.58 vs SL 120.5±1.2, mmHg). The corpus cavernosum of SL rats at PND 120 had increased contraction induced by EFS for all frequencies (1 Hz: NL 0.5 ± 0.2 mN vs SL 0.9 ± 0.2 mN; 4 Hz: NL 1.2 ± 0.3 mN vs SL 1.8 ± 0.2 mN; 16 Hz: NL 1.9 ± 0.4 mN vs SL 3 ± 0.4 mN), whereas the relaxation was decreased (1 Hz: NL 0.77 ± 0.18% vs SL 0.27 ± 0.09%; 4 Hz: NL 2.48 ± 0.26% vs SL 1.36 ± 0.41%; 16 Hz: NL 3.06 ± 0.28% vs SL 2.39 ± 0.53%). CRC showed increased contractile response to Phe (Emax NL 2.3±0.3 vs. SL 3.8± 0.6, mN, p=0.05) and reduced potency of ACh (pEC50 NL 6.4±0.6 vs SL 4.9±0.7, mN, p=0.1) in the corpus cavernosum of SL. Incubation with indomethacin (10uM) abolished the differences in the contractile response induced by EFS or Phe between SL and NL, suggesting a heightened inflammatory response. Conclusions These data suggest that early childhood obesity has long-lasting negative implications on sexual function in adulthood. Disclosure No.

(151) Safety and Feasibility of the COCKTAIL (Combining Shockwave Therapy and Platelet-Rich Plasma for Erectile Dysfunction) Trial: A Single Center, Randomized, Double-Blind, Sham-Controlled Study Update

Abstract Introduction Therapeutic approaches focusing on tissue neovascularization play a crucial role in the development of treatments for erectile dysfunction (ED). Autologous Platelet-Rich Plasma (PRP) and Low-Intensity Shockwave Therapy (SWT) are two restorative therapies that potentially target underlying causes of ED. Pre-clinical evidence suggests their angiogenic and regenerative properties, indicating a potential synergistic pathway to improve vasculogenic ED. Objective The primary objective aims to investigate and compare the treatment efficacy of PRP injection and SWT vs placebo injection/SHAM treatment in men with mild-moderate ED, as measured by IIEF. The secondary objective aims to study incidence of adverse events and safety of PRP injection and SWT treatment in men with mild-moderate ED, as measured by IIEF. Methods The COCKTAIL (Combining Shockwave Therapy and Platelet Rich Plasma) trial is a Phase II, single-center study assessing the safety and efficacy of PRP and SWT in combination for ED (NCT05048667). Thirty-five men with mild to moderate ED were enrolled based on International Index of Erectile Function-EF subdomain (IIEF-EF) questionnaire (12-25). Data from a cohort of men treated with PRP and SWT were analyzed, comparing it to men who received placebo saline injections and sham SWT. Patients received two PRP or placebo injections directly into the corpus cavernosum and penile SWT every week for 5 weeks. Assessment included pain scale evaluations, immediate post-procedure examination, and follow-up for complications. IIEF scores were recorded at baseline, 3-month, and 6-month follow-up visits. All statistics and analyses were conducted with IBM SPSS Statistics 27.0.1. Non-parametric tests were used for analysis. Mann-Whitney U test was used to compare independent groups (Group A vs. Group B) at different time points. Related Samples Wilcoxon -Signed Rank test was used for dependent repeated groups, the serial measurements of IIEF-EF scores at different time points for each patient within a specific group. Findings at p< 0.05 were considered statistically significant. Results The primary endpoint of this study was to investigate the incidence of Serious Adverse Events (SAEs). Encouragingly, no adverse events were reported, suggesting that the procedure appears to be safe for the participants. The median baseline IIEF scores for patients in Group A were 17 (±4), and at the three-month follow-up, the scores increased to 19 (±4), slightly dropping to 18 (±8) at six months. In Group B, the median baseline IIEF scores were 19.50 (±4), which improved to 20 (±7) at the three-month follow-up and further increased to 21 (±10) at six months. No statistical differences were found likely because this is an ongoing study, and we only have complete data for 12 men. We aim to accrue a total of 30 men in each arm and plan to complete the recruitment by January 2024 and complete the study by July 2024. Currently, both the investigators and the patients remain blinded. Conclusions The combination of PRP and SWT appears to be safe, as no adverse events were reported. Although preliminary data do not show differences between the treatment and sham groups currently, we intend to complete the trial to perform a comprehensive statistical calculation for efficacy. Disclosure No.

(066) Targets of SHH Signaling, BMP4 and GREM1, are Downstream Regulators of Smooth Muscle in the Penis

Abstract Introduction A key aspect of erectile dysfunction (ED) development is loss of innervation to the penis. The cavernous nerve (CN) is frequently damaged in prostatectomy and diabetic patients with ED, initiating changes in penile morphology including an acute and intense phase of apoptosis in penile smooth muscle followed by increasing collagen and fibrosis. This remodeling process alters penile architecture so that there is less smooth muscle in the corpora cavernosa, and what remains is less compliant/able to relax in response to normal neurotransmitter signaling, and ED results. Thus, novel therapies are needed which target the underlying remodeling process. We have shown previously that Sonic hedgehog (SHH) is a critical regulator of penile smooth muscle, and that SHH protein treatment suppresses penile remodeling after CN injury through an unknown mechanism. Objective We examine if part of the mechanism of how SHH preserves smooth muscle after CN injury involves bone morphogenetic protein 4 (BMP4) and GREMLIN (GREM1). Methods Primary cultures of smooth muscle cells were established from patients who had prostatectomy, diabetes, hypertension and Peyronie’s (control, n=18). Cultures were characterized by immunohistochemical analysis (IHC) for ACTA2, CD31, P4HB and nNOS. Smooth muscle cell growth was quantified in response to BMP4 and GREM1. Adult Sprague Dawley rats that were uninjured or underwent CN crush injury, were treated with BMP4, GREM1 or MSA (control) proteins via Affi-Gel beads (n=16) or peptide amphiphile (PA, n=26) for 3 and 14 days, and trichrome stain was performed. Sprague Dawley rats underwent CN injury (n=9) and SHH PA treatment for 1, 2 and 4 days (n=9) and western was performed assaying for BMP4 and GREM1 proteins in comparison to sham (n=3) controls. Adult Sprague Dawley rats were treated with 5E1 SHH inhibitor (n=6) or IgG (control, n=6) for 2 and 4 days, and BMP4 and GREM1 localization were examined by IHC. Statistics were performed by ANOVA with Scheffe’s posthoc test. Results Patient primary smooth muscle cultures were established. BMP-4 increased patient smooth muscle cell growth and GREM1 decreased growth. In rats BMP4 treatment via Aff-Gel beads and PA increased smooth muscle growth at 3 and 14 days of treatment. GREM1 treatment caused collagen and smooth muscle growth at 3 days, which switched to primarily collagen at 14 days. CN injury increased BMP4 and GREM1. SHH PA altered western band size suggesting alternative cleavage and range of signaling. SHH inhibition in rats changed BMP4 and GREM1 localization. Conclusions BMP4 treatment increases smooth muscle in patient cultures and in our rat model. BMP4 and GREM1 mediate a switch from smooth muscle to collagen induction. SHH treatment alters BMP4 and GREM1 localization and range of signaling, which can affect penile morphology. Whether GREM1 directly effects collagen induction or acts strictly through inhibition of BMP4 is unknown and requires further study. Part of the mechanism of how SHH regulates corpora cavernosal smooth muscle, involves BMP4 and GREM1. Understanding how SHH PA impacts penile morphology after CN injury will aid development of ED therapies. Disclosure No.

(324) History of Priapism Treatment in the 20th Century

Abstract Introduction Priapism, defined as a prolonged erection in the absence of sexual arousal, leads to decreased quality of life, physical health, and increased erectile dysfunction. The modern priapism treatments of vasoconstriction and cavernous aspiration stem from strides made throughout the last century. Objective As a result, we seek to chronicle the history of priapism treatment throughout the 20th century. Methods We reviewed over two dozen academic articles and medical textbooks from 1872 to 1990 with relevant information on priapism treatment. Results In the 19th century, treatment of priapism solely involved symptomatic management with morphine and medicinal leeches. In 1928, Dr. Robert McKay and Dr. John Colston discovered that a thrombotic condition is sufficient to sustain an erection and that removing clots from the penis is sufficient to alleviate the erection. They recommended the newly-discovered anticoagulant heparin as a potential remedy. Dr. Rita Franklin then established in 1940 a positive association between testosterone propionate levels and priapism in eunuchoid men. Priapism therapies improved exponentially beginning in the late 1950s. Dr. H. Stephen Brody conducted the first successful penile aspiration in 1957 by aspirating blood from the base of each corpus cavernosum in a hypotensive patient. This groundbreaking procedure is conducted to this day for patients who do not respond effectively to medication management. Nine years after Dr. Brody’s study in 1966, Dr. Robert Garrett and Dr. Donald Rhamy reported penile flaccidity and sexual satisfaction in five patients who underwent a corpus-saphenous shunt to improve venous drainage. In 1997, Dr. Pierre Bondil and colleagues conducted a novel experiment demonstrating the efficacy of vasoconstrictive alpha agonist agents in decreasing penile blood flow to decrease erections and preserve erectile function. Conclusions The last one hundred years has shown significant innovation in the treatment of priapism. Some of the major developments in the first half of the 20th century included the use of heparin and the establishment of a relationship between testosterone and priapism. The second half of the 20th included treatment still in use today, such as carvenoglandular shunts and vasoconstrictive agents. Therapies from the 20th century will continue to play a vital role in the treatment and research of priapism management. Disclosure No.

Inhibition of YAP1 Rescues Erectile Dysfunction by Inhibiting Phenotypic Modulation through Myocardin in Diabetic Rats

Background. Phenotypic modulation was shown to be related to the pathological mechanism of diabetes mellitus erectile dysfunction (DMED), and excessive expression of YAP1 was measured in the cavernous tissues of rats with DMED. Objectives. This investigation was performed to explore the efficiency and mechanism of gene therapy through the knockdown of YAP1 in the field of ED treatment. Materials and Methods. Corpus cavernosum smooth muscle cells were obtained and cultivated in vitro employing the explant technique. EdU, CCK-8, and collagen gel lattice contraction assays were subsequently performed to assess cell proliferation and contractility, which indicate smooth muscle phenotypes. Results. Initially, overexpression of YAP1 enhanced the proliferation and expression of YAP1 and osteopontin (OPN) while reducing cell contractility and the expression of myocardin, α-SMA, and calpontin, which is consistent with phenotypic modulation. Moreover, knocking down YAP1 resulted in the opposite effects, and the blockade of myocardin attenuated the reversal of phenotypic transformation. Then, 45 screened DMED rats were randomly divided into three equal groups, named streptozotocin (STZ)-induced DMED with intracavernosal injection of Ad-myocardin (DMED + myocardin), DMED with lenti-shYAP1 (DMED + shYAP1) and DMED with PBS (DMED + PBS), and 10 rats were in the negative control group. Staining with H&E and Masson’s trichrome, immunochemistry, and determination of the ratio of the intracavernosal pressure/mean arterial pressure were performed to evaluate penile erection and histological changes. Western blotting was conducted to determine the molecular protein expression levels. In vivo, similar to myocardin overexpression, YAP1 inhibition rescued erectile function, repaired morphology, and maintained the contractile phenotype of smooth muscle tissues 14 days after treatment. Discussion and Conclusion. In conclusion, our study demonstrated the validity of gene therapy by downregulating excessive YAP1 expression to ameliorate ED in diabetic rats, and the ability of YAP1 inhibition to reverse phenotypic modulation was mediated through interaction with myocardin.

(019) Malignant Priapism: Case Report and Update on Management Protocols

Abstract Introduction Malignant priapism is a rare condition characterized by persistent erection resulting from the invasion or metastasis of a primary neoplasm. Penile metastases arise from the genitourinary tract 64% of the time (bladder: 28.6%, prostate: 27.9%, kidney: 6.9%, ureter: 0.5%) with colorectal adenocarcinoma, lung cancer, melanoma, and hematologic diseases comprising the remainder. Malignant priapism is reported to occur in 20-53% of patients with penile metastasis. The mechanism of malignant priapism remains unknown. The most accepted theory is an invasion of the corpus cavernosum as well as associated venous systems with malignant cells. This can occur from either hematogenous or lymphatic spread from the source tumor. Resulting derangement of arterial or veno-occlusive mechanism causes priapism. Both ischemic and non-ischemic priapism can occur. Objective While treatment guidelines for priapism in non-malignant cases have been established, there is currently no guideline for treating malignant priapism. This study aims to present three cases of malignant priapism resulting from advanced genitourinary cancers and evaluate the efficacy of palliative penectomy as a treatment modality for relieving symptoms associated with malignant priapism. Methods We conducted a retrospective analysis of three cases of malignant priapism associated with advanced genitourinary cancers. Data were collected from medical records, including patient demographics, primary tumor characteristics, clinical presentation, treatment modalities, complications, and outcomes. The main treatment approach utilized in all cases was palliative penectomy. Symptom relief and complications were assessed as primary outcomes. Results All three patients presented with progressive penile pain, and imaging studies confirmed the presence of metastatic disease involving the penile structures. Palliative penectomy was performed in all cases, resulting in sustained relief of symptoms. No major complications were reported during the surgical procedures. Follow-up assessments showed improved quality of life in terms of pain relief, but all patients died within a short period following penectomy owing to the advanced predisposing malignancy. (figure 1) Conclusions Treatment of malignant priapism needs to be individualized to the needs of the patient. No matter the primary or secondary nature of the disease, current data suggest that malignant priapism is associated with poor outcomes, and emphasis should be put on palliative care. Although new radiation techniques have shown favorable outcomes, penectomy should be considered the last resort in clinical management. Revisions to the existing management guidelines for priapism are necessary to address its occurrence in malignant contexts. (figure 2) Disclosure No.

(404) National Trends of Penile Fracture Encounters 2016-2019

Abstract Introduction Penile Fracture (PF) is an acute urological emergency resulting from the rupture of the tunica albuginea and one or both of the corpus cavernosa. Immediate surgical intervention is crucial in avoiding long-term complications, however the epidemiology and treatment patterns remain understudied, especially with the introduction of the 10th Revision of the International Classification of Diseases (ICD-10). Objective To evaluate national trends of PF encounters as well as predictive factors of inpatient admission from the emergency department (ED). Methods All patients admitted to the ED for PF between 2016-2019 were extracted from the NEDS using the ICD-10 Diagnosis Code S39.840 and its modifiers. Multivariable logistic regression was performed to identify predictors of this inpatient admission. Results Between 2016-2019, there were an estimated 7,091 weighted encounters related to PF in the US with an overall 13% increase in cases (Figure 1). About 20.8% (1,477) of these encounters led to inpatient admission. The average age of a patient presenting with PF was 41 years old. The majority of encounters took place in the South (44.12%) at non-trauma center rural hospitals (63.99%) and involved private insurance holders (44.42%). For those admitted to inpatient service, the average length of stay was 1.44 days, with a maximum of 26 days. The average total charge for patients discharged from the ED was $11,224 USD and those admitted were faced with charges averaging $33,474 USD. Predictors of inpatient admission included an Elixhauser Comorbidity Score > 1, encounters in the Northeast, Midwest, and Western states, and being covered by Medicaid (p < .05). Conclusions Penile fractures have seen a small increase in incidence from 2016-2019. Although inpatient admissions are less common, they carry significantly higher costs. Further studies of treatments and regional analysis may be warranted to decrease the amount of inpatient admissions. Disclosure No.

The usefulness of shear wave elastography in evaluating erectile dysfunction severity before and after prostaglandin E1 test.

Prostaglandin E1 intracavernous injection test is an established method for diagnosing erectile dysfunction. However, the evaluation is non-objective and often influenced by the evaluator's subjectivity. Herein, we measured and objectively evaluated shear wave elastography results of the corpus cavernosum before and after injection in 16 patients who underwent prostaglandin E1 testing. The response score of prostaglandin E1 tests were "1" in 2 cases, "2" in 2 cases, and "3" in 12 cases. The average transmission velocity before the injection and at the time of maximum erection after the injection were 2.21 m/s and 1.57 m/s, respectively. Transmission velocity decreased during erection in 14 of 16 cases (87.5%). The overall rate of change in transmission velocity due to injection was -26.7% and was significantly different between the poor (responses 1 and 2: -16.1%) and good erection (response 3: -30.2%) groups. To the best of our knowledge, this is the first attempt to evaluate erectile phenomenon using percutaneous ultrasonic elastography in Japan. Rate of change in shear wave transmission velocity due to prostaglandin E1 injection in the corpus cavernosum penis was associated with the degree of erection. Therefore, the rate of change in shear wave transmission velocity in the corpus cavernosum penis could be used as an objective index of erectile phenomenon. Percutaneous ultrasonic elastography is a non-invasive and useful test method for diagnosing erectile dysfunction, determining the therapeutic effect, and predicting prognosis.

Prolonged ischemic priapism in an adolescent with sickle cell anemia: Challenges of management

Introduction: Persistent penile erection lasting more than 4 hours and unrelated to sexual interest or stimulation is called priapism. Priapism is uncommon in children. Of the three widely accepted types: ischemic, non-ischemic, and stuttering priapism; ischemic priapism is the predominant type seen in children. A common cause of ischemic priapism in children is sickle cell disease. Ischemic priapism of prolonged duration is associated with a higher risk of complications especially irreversible loss of erectile function. It is a difficult clinical condition to manage and there are no established guidelines for its management in children. Adequate surgical treatment does not guarantee against the risk of devastating longterm sequelae. Case Report: We report a case of a 12-year-old boy with sickle cell anemia who presented after 48 hours of sustained painful penile erection. He required multiple surgical shunting procedures including distal corporoglanular shunt with tunneling of both corpora cavernosa with Hegar’s dilator to achieve detumescence. The management challenges encountered are highlighted. Conclusion: A potential role for anticoagulation and the use of low-dose hydroxyurea in the prevention of recurrent ischemic priapism in children with sickle cell anemia are advocated.

3-Hydroxy-3-methylglutaryl-CoA synthase 2 facilitates erectile dysfunction via inhibiting autophagy by enhancing the mammalian target of rapamycin pathway in type 1 diabetic mellitus rats.

The relationship between erectile dysfunction (ED) and type 1 diabetes mellitus (T1DM) is currently a hot topic of medical research. It has been reported that autophagy plays a crucial role in causing erectile dysfunction in T1DM. Recent research has shown that mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2) is strongly linked to the development of T1DM. However, the specific mechanism by which it regulates the erectile function is not yet fully understood. To investigate whether HMGCS2 affects erectile function in type 1 diabetic rats by regulating autophagy in corpus cavernosum endothelial cells (CCECs). First, the rat model of T1DM was established. Then, the ratio of maximum penile intracavernous pressure (ICPmax) and mean arterial pressure (MAP) was detected to assess the erectile function in various groups, and the protein expression of HMGCS2, mTOR and p-mTOR was evaluated by western blot (WB) and immunohistochemistry (IHC). To explore the relationship between HMGCS2 and the mTOR signaling pathway in T1DM ED rats, we silenced the expression of HMGCS2 and activated the mTOR signaling pathway with MHY1485 in CCECs and then assessed the expression of beclin1, P62, LC3, autophagosome, endothelial nitric oxide synthase (eNOS), phosphorylation of eNOS (p-eNOS), and nitric oxide (NO) to evaluate autophagy and the erectile function by reverse transcription quantitative polymerase chain reaction and western blot. The study conducted on T1DM ED rats showed that the expression of HMGCS2 was significantly increased, while the autophagy was suppressed. Additionally, the mTOR signaling pathway was highly activated. In contrast, when HMGCS2 was silenced in vitro, p-mTOR/mTOR was reduced, and autophagy was improved. These effects were accompanied by the enhanced activity of eNOS. Furthermore, when HMGCS2 was silenced and the mTOR signaling pathway was simultaneously activated, the results revealed a decrease in autophagy as well as a reduction in activity of eNOS in comparison to just silencing HMGCS2 alone. HMGCS2 upregulation in T1DM rats inhibited autophagy and eNOS activity by activating the mTOR pathway and led to a decrease in the erectile function.

Nitric Oxide Resistance in Priapism Associated with Sickle Cell Disease: Mechanisms, Therapeutic Challenges, and Future Directions.

Patients with sickle cell disease (SCD) display priapism, a prolonged penile erection in the absence of sexual arousal. The current pharmacological treatments for SCD-associated priapism are limited and focused on acute interventions rather than prevention. Thus, there is an urgent need for new drug targets and preventive pharmacological therapies for this condition. This review focuses on the molecular mechanisms linked to the dysfunction of the NO-cyclic guanosine monophosphate (cGMP)-phosphodiesterase type 5 (PDE5) pathway implicated in SCD-associated priapism. In murine models of SCD, reduced nitric oxide (NO)-cGMP bioavailability in the corpus cavernosum is associated with elevated plasma hemoglobin levels, increased reactive oxygen species levels that inactive NO, and testosterone deficiency that leads to endothelial nitric oxide synthase downregulation. We discuss the consequences of the reduced cGMP-dependent PDE5 activity in response to these molecular changes, highlighting it as the primary pathophysiological mechanism leading to excessive corpus cavernosum relaxation, culminating in priapism. We also further discuss the impact of intravascular hemolysis on therapeutic approaches, present current pharmacological strategies targeting the NO-cGMP-PDE5 pathway in the penis, and identify potential pharmacological targets for future priapism therapies. In men with SCD and priapism, PDE5 inhibitor therapy and testosterone replacement have shown promising results. Recent preclinical research reported the beneficial effect of treatment with haptoglobin and NO donors. SIGNIFICANCE STATEMENT: This review discusses the molecular changes that reduce NO-cGMP bioavailability in the penis in SCD and highlights pharmacological targets and therapeutic strategies for the treatment of priapism, including PDE5 inhibitors, hormonal modulators, NO donors, hydroxyurea, soluble guanylate cyclase stimulators, haptoglobin, hemopexin, and antioxidants.

ADSCs labeled with SPIONs tracked in corpus cavernosum of rat and miniature pig by MR imaging and histological examination

Adipose tissue-derived stem cells (ADSCs) have been shown to improve erectile function in animal models of erectile dysfunction. However, few studies have been carried out using a reliable in vivo imaging method to trace transplanted cells in real time, which is necessary for systematic investigation of cell therapy. The study aims to explore the feasibility of non-invasively monitoring intracavernous injection of ADSCs in rat and miniature pig corpus cavernosum using in vivo magnetic resonance (MR) imaging. Thirty-six male Sprague Dawley rats (10 weeks old) and six healthy, sexually mature male miniature pigs (20 kg weight) were obtained. ADSCs were isolated from paratesticular fat of donor rats and cultured. Then ADSCs were labeled with superparamagnetic iron oxide nanoparticles (SPIONs), a type of MR imaging contrast agent, before transplantation into rats and pigs. After intracavernous injection, all rats and pigs underwent and were analyzed by MR imaging at the day of ADSC transplantation and follow-up at 1, 2 and 4 weeks after transplantation. In addition, penile histological examination was performed on all rats and pigs before (n = 6) and at 1 day (n = 6), 1 week (n = 6), 2 weeks (n = 6) or 4 weeks (n = 12) after ADSC transplantation. SPION-labeled ADSCs demonstrated a strong decreased signal intensity compared with distilled water, unlabeled ADSCs or agarose gel. SPION-labeled ADSCs showed a hypointense signal at all concentrations, and the greatest hypointense signal was observed at the concentration of 1 × 106. MR images of the corpus cavernosum showed a hypointense signal located at the injection site. T2*-weighted signal intensity increased over the course of 1 week after ADSCs transplantation, and demonstrated a similar MR signal with that before ADSCs transplantation. After SPION-labeled ADSC injection, T2*-weighted MR imaging clearly demonstrated a marked hypointense signal in pig corpus cavernosum. The T2*-weighted signal faded over time, similar to the MR imaging results in rats. Obvious acute inflammatory exudation was induced by intracavernous injection, and the T2*-weighted signal intensity of these exudation was higher than that of the injection site. The presence of iron was detected by Prussian blue staining, which demonstrated ADSC retention in rat corpus cavernosum. Lack of cellular infiltrations were demonstrated by H&E staining before and 4 weeks after transplantation, which indicated no negative immune response by rats. Prussian blue staining was positive for iron oxide nanoparticles at 2 weeks after transplantation. SPION-labeled ADSCs showed a clear hypointense signal on T2-weight MRI in vitro and in vivo. The MR signal intensity in the corpus cavernosum of the rats and miniature pigs faded and disappeared over time after ADSC transplantation. These findings suggested that MR imaging could trace transplanted ADSCs in the short term in the corpus cavernosum of animals.

Heme-induced corpus cavernosum relaxation and its implications for priapism in sickle cell disease: a mechanistic insight.

Patients with sickle cell disease (SCD) experience intravascular hemolysis, leading to elevated plasma heme levels. This phenomenon has been associated with increased priapism in men with SCD. The heme group can be metabolized by heme oxygenase (HO), generating carbon monoxide (CO), which is known to promote smooth muscle relaxation via soluble guanylyl cyclase (sGC)-cyclic guanosine monophosphate (cGMP). However, the effects of heme on the relaxation responses of corpus cavernosum (CC) have not been investigated. To evaluate the functional and biochemical effects of the heme group on mouse CC smooth muscle in vitro. Male C57BL/6 mice were used. CC tissues were mounted in organ baths. Measurement of cGMP in mice CC was evaluated. The cumulative addition of heme concentrations promoted the relaxation of CC. HO inhibitor (1J, 100μM) or sGC inhibitor (ODQ, 10μM) blocked the relaxing effect of the heme group. Pre-incubation of CC with heme (100μM) enhanced relaxation induced by acetylcholine, sodium nitroprusside, and nitrergic relaxation (electrical field stimulation), which was abolished by 1J or ODQ. The heme group increased the cGMP production in CC, which was abolished by 1J or ODQ. cGMP levels were significantly higher in CC treated with heme, and pre-incubation with compound 1J or ODQ abolished the effect of heme in raising cGMP levels. The HO-CO-sGC-cGMP pathway appears to play a crucial role in promoting CC relaxation. Our study provides novel insight into the role of group heme in CC relaxation and its potential contribution to priapism in SCD. Heme may serve as a pharmacological target for new therapies to prevent priapism.

MiRNA-100 ameliorates diabetes mellitus-induced erectile dysfunction by modulating autophagy, anti-inflammatory, and antifibrotic effects.

Diabetes mellitus-induced erectile dysfunction (DMED) has become a common disease in adult men that can seriously reduce the quality of life of patients, and new therapies are urgently needed. miRNA-100 has many targets and can induce autophagy and reduce fibrosis by inhibiting the mTOR pathway and the TGF-β pathway. However, no research has been conducted with miR-100 in the field of DMED, and the specific mechanism of action is still unclear. To ascertain the effects of miR-100 on corpus cavernosum tissue of DMED rats and vascular endothelial cells in a high glucose environment and to elucidate the relevant mechanisms in autophagy, fibrosis and inflammation to find a new approach for the DMED therapy. Thirty rats were divided into three groups: the control group, the DMED group, and the DMED + miR-100 group. Using intraperitoneal injections of streptozotocin, all rats except the control group were modeled with diabetes mellitus, which was verified using the apomorphine (APO) test. For rats in the DMED + miR-100 group, rno-miR-100-5p agomir (50nmol/kg, every 2 days, 6 times in total) was injected via the tail vein. After 13weeks, the erectile function of each rat was assessed using cavernous manometry, and the corpus cavernosum tissue was harvested for subsequent experiments. For cellular experiments, human coronary microartery endothelial cells (HCMEC) were divided into four groups: the control group, the high-glucose (HG, 40mM) group, the HG + mimic group, and the HG + inhibitor group. The cells were cultured for 6 days and collected for subsequent experiments 2 days after transfection. Diabetic modeling impaired the erectile function in rats, and miR-100 reversed this effect. By measuring autophagy-related proteins such as mTOR/Raptor/Beclin1/p62/LC3B, we found that miR-100 could suppress the expression of mTOR and induce autophagy. The analysis of the eNOS/NO/cGMP axis function indicated that impaired endothelial function was improved by miR-100. By evaluating the TGF-β1/CTGF/Smad2/3 and NF-κB/TNF-α pathways, we found that miR-100 could lower the level of inflammation and fibrosis, which contributed to the improvement of the erectile function. Cellular experiments can be used as supporting evidence for these findings. MiR-100 can improve the erectile function by inhibiting mTOR and thus inducing autophagy, improving the endothelial function through the eNOS/NO/cGMP axis, and exerting antifibrotic and anti-inflammatory effects, which may provide new ideas and directions for the treatment of DMED.

Knockdown of programmed cell death factor 4 restores erectile function by attenuating apoptosis in rats with bilateral cavernous nerve crush injury.

Apoptosis is an important pathologic mechanism of erectile dysfunction after radical prostatectomy. Studies have shown that programmed cell death factor 4 is connected to the modulation of apoptosis in many cells. However, the programmed cell death factor 4 function in the cavernous nerve injury erectile dysfunction is unclear. This investigation aimed to explore the programmed cell death factor 4 function in erectile dysfunction in rats with bilateral cavernous nerve crush. The experiment used 30 male Sprague Dawley rats (18 months old) that were screened for normal erectile function by the apomorphine test. Ten rats were randomized into Sham and bilateral cavernous nerve crush groups to detect changes in programmed cell death factor 4 expression. The remaining 20 rats were distributed at random to four groups: the Sham group treated by sham surgery, the phosphate-buffered saline group, the lentivirus containing negative control short hairpin RNA group, and the lentivirus containing short hairpin RNA targeting programmed cell death factor 4 group underwent bilateral cavernous nerve crush and were afterward administered intracavernous injections of phosphate-buffered saline, lentivirus containing negative control short hairpin RNA, or lentivirus containing short hairpin RNA targeting programmed cell death factor 4. Electrical stimulation of the cavernous nerve was conducted 2 weeks later for penile erectile function assessment. The cavernous tissue was collected for histological analysis and western blotting. The apoptosis level in rat corpus cavernosum was elevated, and programmed cell death factor 4 expression was increased after bilateral cavernous nerve crush. Knockdown of programmed cell death factor 4 significantly improved erectile function in bilateral cavernous nerve crush rats. Furthermore, lentivirus containing short hairpin RNA targeting programmed cell death factor 4 treatment raised smooth muscle content and attenuated cavernous fibrosis and apoptotic levels. Additionally, programmed cell death factor 4 was found to mediate the PI3K/AKT pathway. Elevated programmed cell death factor 4 expression may be an important pathogenetic mechanism for erectile dysfunction after bilateral cavernous nerve crush, and the knockdown of programmed cell death factor 4 enhanced erectile function in 18-month-old rats after cavernous nerve damage. The potential mechanism may be the stimulation of the PI3K/AKT pathway to attenuate the cavernous apoptosis level.

MicroRNA-145 Gene Modification Enhances the Retention of Bone Marrow-Derived Mesenchymal Stem Cells within Corpus Cavernosum by Targeting Krüppel-Like Factor 4.

The poor retention and ambiguous differentiation of stem cells (SCs) within corpus cavernosum (CC) limit the cell application in erectile dysfunction (ED). Herein, the effects and mechanism of microRNA-145 (miR-145) gene modification on modulating the traits and fate of bone marrow-derived mesenchymal stem cells (BMSCs) were investigated. The effects of miR-145 on cell apoptosis, proliferation, migration, and differentiation were determined by flow cytometry, cell counting kit-8, transwell assays and myogenic induction. Then, the age-related ED rats were recruited to four groups including phosphate buffer saline, BMSC, vector-BMSC, overexpressed-miR-145-BMSC groups. After cell transplantation, the CC were harvested and prepared to demonstrate the retention and differentiation of BMSCs by immunofluorescent staining. Then, the target of miR-145 was verified by quantitative real-time polymerase chain reaction and immunohistochemical. After that, APTO-253, as an inducer of Krüppel-like factor 4 (KLF4), was introduced for rescue experiments in corpus cavernosum smooth muscle cells (CCSMCs) under the co-culture system. In vitro, miR-145 inhibited the migration and apoptosis of BMSCs and promoted the differentiation of BMSCs into smooth muscle-like cells with stronger contractility. In vivo, the amount of 5-ethynyl-2'-deoxyuridine (EdU)+cells within CC was significantly enhanced and maintained in the miR-145 gene modified BMSC group. The EdU/CD31 co-staning was detected, however, no co-staining of EdU/α-actin was observed. Furthermore, miR-145, which secreted from the gene modified BMSCs, dampened the expression of KLF4. However, the effects of miR-145 on CCSMCs could be rescued by APTO-253. Overall, miR-145 modification prolongs the retention of the transplanted BMSCs within the CC, and this effect might be attributed to the modulation of the miR-145/KLF4 axis. Consequently, our findings offer a promising and innovative strategy to enhance the local stem cell-based treatments.