Diabetic Erectile Dysfunction Research Articles

The multifaceted nature of diabetic erectile dysfunction: uncovering the intricate mechanisms and treatment strategies

BackgroundOne of the most common complications of diabetes mellitus is diabetic erectile dysfunction (DMED), a condition that has grown more common in recent years and has a significant impact on patients’ daily lives. The complicated pathophysiological changes of DMED, involving vascular, neurological, muscular, and endocrine variables, have not been well addressed by any one treatment technique, and no widely approved treatment strategy has been developed.AimThe objective of this study was to thoroughly examine the complex nature of the pathogenic mechanism of DMED and discover new therapeutic approaches that could improve DMED symptoms.MethodsStudies and review articles from the past 10 years were considered.ResultsThe pathogenesis of DMED encompasses vascular dysfunction, endothelial cell damage, cavernous smooth muscle defects, neurological dysfunction, endocrine/metabolic factors, leukomalacia fibrosis, and psychosocial factors, elucidating complex interplay among the mechanisms underlying DMED. It underscores the need of integrating traditional herbal medicine, energy-based medicine treatments, and advanced techniques like stem cell and gene therapy to enhance therapeutic outcomes. Furthermore, it expresses optimism on the therapeutic potential of new nanobiomaterials in DMED.ConclusionThrough integrating a complete description of DMED etiology and current therapy methods, this work offers a helpful resource for researchers, doctors, and patients dealing with this difficult condition.

Exploring You-gui Pill for the Treatment of Diabetic Erectile Dysfunction: Data Mining Analysis, Network Pharmacology and Experiments In Vitro.

The You-gui pill (YGP) is a classical compound used for treating antidiabetic erectile dysfunction (DMED). However, the specific active ingredients responsible for its effects on DMED and their mechanisms remain unclear. In this paper, we used data mining techniques to analyze high-frequency herbs and herb combinations used in Chinese medicine for the treatment of DMED based on existing literature. Using network pharmacology to study the active components and mechanism of action of YGP against DMED, molecular docking was used to analyze the interactions of the active components with major structural proteins, nonstructural proteins, and mutants. Also, the therapeutic effect of YGP on hyperglycemic modelling and its underlying mechanisms were experimentally validated in CCEC cells by analyzing the expression of its relevant target mRNAs. Network pharmacological analysis identified the three core components of YGP as quercetin, kaempferol, and β-sitosterol, and constructed a PPI network map of common targets of YGP and DMED, which included HIF-1α, ALB, Bcl-2, INS, IL-1β, IL-6, TNF-α, CASP3, and TP53. Combined with molecular docking results, these targets had a strong binding affinity between them and the active ingredient compounds, with the highest affinity for HIF-1α and TNF-α. During the in vitro cellular assay validation, the HIF-1α, ALB, Bcl-2, TNF-α, and IL-6 mRNA in CCECs cells showed positive regulation after YGP intervention. The combination of "data mining - network pharmacology - molecular docking - experimental validation" provides a powerful methodological basis for the study of the main active components and mechanism of action of YGP against DMED, as well as the development and application of the drug.

Therapeutic Effects of Proanthocyanidins on Diabetic Erectile Dysfunction in Rats.

The rising occurrence of erectile dysfunction related to diabetes mellitus (DMED) has led to the creation of new medications. Proanthocyanidins (PROs) is a potential agent for DMED. In this study, the DMED rat model was established using streptozotocin (STZ) and erectile function was assessed using apomorphine (APO) in rats. Following this, the rats were subjected to oral treatment with PRO. Then, we evaluated the influence of PROs on DMED rats. The findings suggest that PROs significantly enhance erectile function in DMED rats. PROs modulated glucose and lipid metabolism in DMED rats by decreasing blood glucose and lipid levels while increasing liver glycogen and serum insulin levels. Furthermore, PROs enhanced vascular endothelial function in DMED rats by augmenting nitric oxide (NO) levels and reducing the levels of endothelin-1 (ET-1) and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1). Additionally, PROs have been shown to elevate testosterone (T) levels, mitigate pathological testicular damage, and enhance sperm concentration and survival rates. Finally, the core targets were screened using network pharmacology, followed by validation through molecular docking, enzyme-linked immunoassay (ELISA), and real-time PCR methodologies. Our findings imply that PROs may treat DMED by elevating AKT1 levels while concurrently diminishing CASP3 levels, thereby effectively regulating the PI3K-Akt signaling pathway. Overall, these results support using PROs as a potential candidate for the treatment of DMED.

Nesfatin-1 regulates the phenotype transition of cavernous smooth muscle cells by activating PI3K/AKT/mTOR signaling pathway to improve diabetic erectile dysfunction.

This study aims to explore the impact of Nesfatin-1 on type 2 diabetic erectile dysfunction (T2DMED) and its underlying mechanism in regulating the phenotypic switching of corpus cavernosum smooth muscle cells (CCSMCs). Twenty-four 4-week-old male C57 wild-type mice were randomly assigned to the control group, model group, and Nesfatin-1 treatment group. Monitoring included body weight, blood glucose levels, and penile cavernous pressure (ICP). Histochemistry and Western blot analyses were conducted to assess the expressions of α-SMA, OPN, and factors related to the PI3K/AKT/mTOR signaling pathway. CCSMCs were categorized into the control group, high glucose and high oleic acid group (GO group), Nesfatin-1 treatment group (GO+N group), sildenafil positive control group (GO+S group), and PI3K inhibitor group (GO+N+E group). Changes in phenotypic markers, cell morphology, and the PI3K/AKT/mTOR signaling pathway were observed in each group. (1) Nesfatin-1 significantly ameliorated the body size, body weight, blood glucose, glucose tolerance, and insulin resistance in T2DMED mice. (2) Following Nesfatin-1 treatment, the ICP/MSBP ratio and the peak of the ICP curve demonstrated a significant increase. (3) Nesfatin-1 significantly enhanced smooth muscle and reduced collagen fibers in the corpus cavernosum. (4) Nesfatin-1 notably increased α-SMA expression and decreased OPN expression in CCSMCs. (5) Nesfatin-1 elevated PI3K, p-AKT/AKT, and p-mTOR/mTOR levels in penile cavernous tissue. Nesfatin-1 not only effectively improves body weight and blood glucose levels in diabetic mice but also enhances erectile function and regulates the phenotypic switching of corpus cavernosum smooth muscle. The potential mechanism involves Nesfatin-1 activating the PI3K/AKT/mTOR signaling pathway to induce the conversion of CCSMCs to a contractile phenotype.

Evaluation of Erectile Dysfunction in Prediabetic Males at Tertiary Care Center in Central India.

Erectile dysfunction (ED) is a well-studied entity in diabetes mellitus (DM). As with DM, prediabetes also appears to be associated with changes in microvascular-related comorbidities. These include retinopathy, neuropathy, nephropathy, and ED. ED is a condition characterized by an inability to maintain penile erection for adequate sexual activity, either consistently or recurrently. Endothelial damage due to any cause corresponding to hyperglycemia signifies the relationship between prediabetes and ED. While the evaluation of ED in diabetics has been extensively studied worldwide, there is a paucity of knowledge about ED among prediabetics. The study type was observational and was conducted at a tertiary center in India. Adult males aged 18-50 years with prediabetes were included in the study over a duration of 18 months. Evaluation for ED was performed using the International Index of Erectile Function 5 (IIEF-5). A total of 139 participants were enrolled in the present study. The severity of ED was categorized as follows: 32.4% of participants had mild ED, 11.5% had mild-to-moderate ED, and 6.5% had moderate ED. A positive association was found between prediabetes-related parameters and ED. There is a significant prevalence of ED in prediabetic males compared to the general population, as found in our study. Overall, 50.3% of participants were found to have ED. We recommend exploring this subject with more structured and larger studies.

Role of pericytes in regulating penile angiogenesis and nerve regeneration.

Pericytes are multifunctional mural cells that surround the abluminal wall of endothelial cells and are associated with vascular development, vascular permeability, and angiogenesis. Additionally, pericytes demonstrate stem cell-like properties and contribute to neuroinflammatory processes. Pericytes have been extensively studied in the central nervous system. However, specific mechanisms underlying its involvement in various physiological and pathological conditions, especially in erectile dysfunction (ED), remain poorly understood. Advancements in in vitro and in vitro techniques, such as single-cell RNA sequencing, are expanding our understanding of pericytes. Recent studies have shown that pericyte dysfunction is considered an important factor in the pathogenesis of vascular and neurological ED. Therefore, this study aims to analyze the specific role of pericytes in ED, focusing on diabetic and neurogenic ED. This article provides a comprehensive review of research findings on PubMed from 2000 to 2023, concerning pericyte dysfunction in the process of ED, offering valuable insights, and suggesting directions for further research.

Association between erectile dysfunction and the prevalence and prognosis of hyperglycemia in adults in the USA based on NHANES 2001–2004

Prior research has demonstrated that erectile dysfunction (ED) is a significant risk factor for cardiovascular disease (CVD) and premature mortality. Few studies have examined the link between ED and hyperglycemia, and the predictive power of ED for mortality in individuals with hyperglycemia. A cohort of 1584 adults diagnosed with hyperglycemia, consisting of 583 individuals with diabetes and 1001 individuals with prediabetes, was selected from the National Health and Nutrition Examination Survey (NHANES) conducted between 2001 and 2004. The study found a positive correlation between severe ED and hyperglycemia (OR, 2.03; 95% CI 1.53–2.68), while no significant relationship was observed between severe ED and CVD events (OR, 1.60; 95% CI 0.91–2.80). Additionally, no statistical association was found between diabetes or prediabetes status and ED. After multivariable adjustments, severe ED was found to be significantly associated with an increased risk of all-cause mortality (HR, 1.67; 95% CI 1.16–2.39), while no significant association was observed between severe ED and CVD mortality (HR, 1.92; 95% CI 0.92–3.98). Our study indicates a significant correlation between ED and hyperglycemia status. Hyperglycemia Individuals with ED generally exhibited an unfavorable prognosis for mortality due to all causes and CVD, particularly among those with low levels of physical activity.

Heparin-binding epidermal growth factor-like growth factor improves erectile function in streptozotocin-induced diabetic mice.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) serves as a pro-angiogenic factor; however, there is to our knowledge currently no reported research on the relationship between HB-EGF and diabetic erectile dysfunction (ED). In this study we aimed to determine whether HB-EGF can improve the erectile function of streptozotocin-induced diabetic mice and to explore the related mechanisms. Eight-week-old male C57BL/6 mice were used for diabetes induction. Diabetes mellitus (DM) was induced by low-dose injections of streptozotocin (50mg/kg) for 5 consecutive days. Eight weeks after streptozotocin injections, DM was determined by measuring blood glucose and body weight. Diabetic mice were treated with two intracavernous administrations of phosphate-buffered saline (20μL) or various doses of HB-EGF (days -3 and 0; 1, 5, and 10μg in 20μL of phosphate-buffered saline). The angiogenesis effect of HB-EGF was confirmed by tube formation and migration assays in mouse cavernous endothelial cells and mouse cavernous pericytes under high-glucose conditions. Erectile function was measured by electrical stimulation of the cavernous nerve, as well as histological examination and Western blot analysis for mechanism assessment. In vitro angiogenesis, cell proliferation, in vivo intracavernous pressure, neurovascular regeneration, cavernous permeability, and survival signaling were the outcomes measured. Expression of HB-EGF was reduced under diabetic conditions. Exogenous HB-EGF induced angiogenesis in mouse cavernous endothelial cells and mouse cavernous pericytes under high-glucose conditions. Erectile function was decreased in the DM group, whereas administration of HB-EGF resulted in a significant improvement of erectile function (91% of the age-matched control group) in association with increased neurovascular content, including cavernous endothelial cells, pericytes, and neuronal cells. Histological and Western blot analyses revealed a significant increase in the permeability of the corpus cavernosum in DM mice, which was attenuated by HB-EGF treatment. The protein expression of phospho-Akt Ser473 and phosphorylated endothelial nitric oxide synthase Ser1177 increased after HB-EGF treatment. The use of HB-EGF may be an effective strategy to treat ED associated with DM or other neurovascular diseases. Similarly to other pro-angiogenic factors, HB-EGF has dual roles in vascular and neuronal development. Our study focused on broadly evaluating the role of HB-EGF in diabetic ED. In view of the properties of HB-EGF as an angiogenic factor, its dose concentration should be strictly controlled to avoid potential side effects. In the diabetic ED mouse model in this study erectile function was improved by HB-EGF, which may provide new treatment strategies for patients with ED who do not respond to phosphodiesterase 5 Inhibitors.

Trackins (Trk-Targeting Drugs): A Novel Therapy for Different Diseases.

Many routes may lead to the transition from a healthy to a diseased phenotype. However, there are not so many routes to travel in the opposite direction; that is, therapy for different diseases. The following pressing question thus remains: what are the pathogenic routes and how can be they counteracted for therapeutic purposes? Human cells contain >500 protein kinases and nearly 200 protein phosphatases, acting on thousands of proteins, including cell growth factors. We herein discuss neurotrophins with pathogenic or metabotrophic abilities, particularly brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), pro-NGF, neurotrophin-3 (NT-3), and their receptor Trk (tyrosine receptor kinase; pronounced "track"). Indeed, we introduced the word trackins, standing for Trk-targeting drugs, that play an agonistic or antagonistic role in the function of TrkBBDNF, TrkCNT-3, TrkANGF, and TrkApro-NGF receptors. Based on our own published results, supported by those of other authors, we aim to update and enlarge our trackins concept, focusing on (1) agonistic trackins as possible drugs for (1a) neurotrophin-deficiency cardiometabolic disorders (hypertension, atherosclerosis, type 2 diabetes mellitus, metabolic syndrome, obesity, diabetic erectile dysfunction and atrial fibrillation) and (1b) neurodegenerative diseases (Alzheimer's disease, Parkinson's disease, and multiple sclerosis), and (2) antagonistic trackins, particularly TrkANGF inhibitors for prostate and breast cancer, pain, and arrhythmogenic right-ventricular dysplasia. Altogether, the druggability of TrkANGF, TrkApro-NGF, TrkBBDNF, and TrkCNT-3 receptors via trackins requires a further translational pursuit. This could provide rewards for our patients.

Nesfatin-1 regulates the phenotype transition of cavernous smooth muscle cells by activating PI3K/AKT/mTOR signaling pathway to improve diabetic erectile dysfunction

ObjectiveThis study aims to explore the impact of Nesfatin-1 on type 2 diabetic erectile dysfunction (T2DMED) and its underlying mechanism in regulating the phenotypic switching of corpus cavernosum smooth muscle cells (CCSMCs). MethodsTwenty-four 4-week-old male C57 wild-type mice were randomly assigned to the control group, model group, and Nesfatin-1 treatment group. Monitoring included body weight, blood glucose levels, and penile cavernous pressure (ICP). Histochemistry and Western blot analyses were conducted to assess the expressions of α-SMA, OPN, and factors related to the PI3K/AKT/mTOR signaling pathway. CCSMCs were categorized into the control group, high glucose and high oleic acid group (GO group), Nesfatin-1 treatment group (GO + N group), sildenafil positive control group (GO + S group), and PI3K inhibitor group (GO + N + E group). Changes in phenotypic markers, cell morphology, and the PI3K/AKT/mTOR signaling pathway were observed in each group. Results(1) Nesfatin-1 significantly ameliorated the body size, body weight, blood glucose, glucose tolerance, and insulin resistance in T2DMED mice. (2) Following Nesfatin-1 treatment, the ICP/MSBP ratio and the peak of the ICP curve demonstrated a significant increase. (3) Nesfatin-1 significantly enhanced smooth muscle and reduced collagen fibers in the corpus cavernosum. (4) Nesfatin-1 notably increased α-SMA expression and decreased OPN expression in CCSMCs. (5) Nesfatin-1 elevated PI3K, p-AKT/AKT, and p-mTOR/mTOR levels in penile cavernous tissue. ConclusionsNesfatin-1 not only effectively improves body weight and blood glucose levels in diabetic mice but also enhances erectile function and regulates the phenotypic switching of corpus cavernosum smooth muscle. The potential mechanism involves Nesfatin-1 activating the PI3K/AKT/mTOR signaling pathway to induce the conversion of CCSMCs to a contractile phenotype.

Single-cell transcriptome analysis of cavernous tissues reveals the key roles of pericytes in diabetic erectile dysfunction.

Erectile dysfunction (ED) affects a significant proportion of men aged 40-70 and is caused by cavernous tissue dysfunction. Presently, the most common treatment for ED is phosphodiesterase 5 inhibitors; however, this is less effective in patients with severe vascular disease such as diabetic ED. Therefore, there is a need for development of new treatment, which requires a better understanding of the cavernous microenvironment and cell-cell communications under diabetic condition. Pericytes are vital in penile erection; however, their dysfunction due to diabetes remains unclear. In this study, we performed single-cell RNA sequencing to understand the cellular landscape of cavernous tissues and cell type-specific transcriptional changes in diabetic ED. We found a decreased expression of genes associated with collagen or extracellular matrix organization and angiogenesis in diabetic fibroblasts, chondrocytes, myofibroblasts, valve-related lymphatic endothelial cells, and pericytes. Moreover, the newly identified pericyte-specific marker, Limb Bud-Heart (Lbh), in mouse and human cavernous tissues, clearly distinguishing pericytes from smooth muscle cells. Cell-cell interaction analysis revealed that pericytes are involved in angiogenesis, adhesion, and migration by communicating with other cell types in the corpus cavernosum; however, these interactions were highly reduced under diabetic conditions. Lbh expression is low in diabetic pericytes, and overexpression of LBH prevents erectile function by regulating neurovascular regeneration. Furthermore, the LBH-interacting proteins (Crystallin Alpha B and Vimentin) were identified in mouse cavernous pericytes through LC-MS/MS analysis, indicating that their interactions were critical for maintaining pericyte function. Thus, our study reveals novel targets and insights into the pathogenesis of ED in patients with diabetes.

Single-cell transcriptome analysis of cavernous tissues reveals the key roles of pericytes in diabetic erectile dysfunction

Erectile dysfunction (ED) affects a significant proportion of men aged 40–70 and is caused by cavernous tissue dysfunction. Presently, the most common treatment for ED is phosphodiesterase 5 inhibitors; however, this is less effective in patients with severe vascular disease such as diabetic ED. Therefore, there is a need for development of new treatment, which requires a better understanding of the cavernous microenvironment and cell-cell communications under diabetic condition. Pericytes are vital in penile erection; however, their dysfunction due to diabetes remains unclear. In this study, we performed single-cell RNA sequencing to understand the cellular landscape of cavernous tissues and cell type-specific transcriptional changes in diabetic ED. We found a decreased expression of genes associated with collagen or extracellular matrix organization and angiogenesis in diabetic fibroblasts, chondrocytes, myofibroblasts, valve-related lymphatic endothelial cells, and pericytes. Moreover, the newly identified pericyte-specific marker, Limb Bud-Heart (Lbh), in mouse and human cavernous tissues, clearly distinguishing pericytes from smooth muscle cells. Cell-cell interaction analysis revealed that pericytes are involved in angiogenesis, adhesion, and migration by communicating with other cell types in the corpus cavernosum; however, these interactions were highly reduced under diabetic conditions. Lbh expression is low in diabetic pericytes, and overexpression of LBH prevents erectile function by regulating neurovascular regeneration. Furthermore, the LBH-interacting proteins (Crystallin Alpha B and Vimentin) were identified in mouse cavernous pericytes through LC-MS/MS analysis, indicating that their interactions were critical for maintaining pericyte function. Thus, our study reveals novel targets and insights into the pathogenesis of ED in patients with diabetes.

Stem cell therapy outcome for diabetic erectile dysfunction: A pilot analysis

Background Many males encounter the condition of erectile dysfunction (ED), particularly individuals diagnosed with type 2 diabetes mellitus (DM). Stem cell therapy is a burgeoning treatment modality being explored for individuals with erectile dysfunction in the context of type 2 DM. Nevertheless, the available body of clinical evidence supporting its efficacy remains limited. This study aims to assess the effectiveness and safety of umbilical cord-derived mesenchymal stem cell (MSC) therapy in managing erectile dysfunction (ED) resulting from type 2 DM. Methods A randomized, double-blind, placebo-controlled trial was conducted at Dr. Cipto Mangunkusumo Hospital in Indonesia from October 2020 to January 2023. A total of 26 eligible patients were randomly assigned to two groups: one receiving intracavernosal injections of MSC and the other receiving a placebo. Follow-up assessments were conducted at baseline, month one, and month three. The primary outcomes were measured using the IIEF-5 questionnaire and dorsal artery peak systolic velocity (PSV). Metabolic markers were used as secondary outcomes. Results The IIEF-5 scores for both groups showed a significant increase (p < 0.001) from baseline to month three. There was no significant difference observed between the MSC and placebo groups. Moreover, no significant differences were observed in the PSV of the dorsal artery between the two groups (p>0.05). There were no significant differences in metabolic markers between the groups. The incidence of mild post-injection pain was reported by only 11% of individuals, indicating a low occurrence of adverse events. Conclusions Intracavernous administration of MSC did not demonstrate superior efficacy compared to a placebo in improving metabolic or erectile function in diabetic males with erectile dysfunction. Additional research utilizing larger sample sizes and more extended follow-up periods is necessary.

Cldn4 overexpression promotes penile cavernous smooth muscle cell fibrotic response via the JNK signaling pathway.

Erectile dysfunction (ED), defined as the inability to achieve or maintain a penile erection sufficient to satisfy sexual behavior, is prevalent worldwide. Using previous research, bioinformatics, and experimental confirmation, we aimed to discover genes that contribute to ED through regulating hypoxia in corpus cavernosum smooth muscle cells (CCSMCs). We used the Gene Expression Omnibus to acquire the sequencing data of the corpus cavernosum transcriptome for diabetic ED and nerve injury type ED rats. We intersected the common differentially expressed genes. Further verification was performed using single cell sequencing. Real-time quantitative polymerase chain reaction and immunofluorescence were used to investigate whether the differentially expressed genes are found in the corpus cavernosum. We used induced hypoxia to assess cell viability changes, and we developed a lentivirus overexpressing Cldn4 for in vitro and in vivo experiments to measure changes in JNK signaling, fibrosis, hypoxia, and erectile function. Our results indicate that targeting the JNK pathway and decreasing local hypoxia may be better options for therapeutic intervention to improve erectile function. We identified Cldn4 and found its expression increased in the corpora cavernosa of the 2 datasets. In addition, we found that hypoxia can increase the expression of Cldn4, activate the JNK signaling pathway, and exacerbate fibrosis in CCSMCs. Cldn4 overexpression in CCSMCs activated the JNK signaling pathway and increased fibrotic protein expression. Last, rat corpus cavernosum overexpressing Cldn4 activated the JNK signaling pathway, increased local fibrosis, and impaired erectile function. Through bioinformatics and in vitro and in vivo experiments, we found that Cldn4 has a negative effect on ED, and targeting Cldn4 may provide new ideas for ED treatment. Although we have identified Cldn4 as a potential target for ED treatment, we have only conducted preliminary validation on CCMSCs, and we still need to further validate in other cell lines. CCSMC hypoxia leads to increased Cldn4, in both nerve injury and diabetic ED rat models, and promotes fibrosis by activating the JNK signaling pathway.

PKC Inhibition Improves Human Penile Vascular Function and the NO/cGMP Pathway in Diabetic Erectile Dysfunction: The Role of NADPH Oxidase.

Erectile dysfunction (ED) is a frequent and difficult-to-treat condition in diabetic men. Protein kinase C (PKC) is involved in diabetes-related vascular and cavernosal alterations. We aimed to evaluate the role of PKC in endothelial dysfunction and NO/cGMP impairment associated with diabetic ED in the human corpus cavernosum (CC) and penile resistance arteries (PRAs) and the potential mechanisms involved. Functional responses were determined in the CC and PRAs in patients with non-diabetic ED and diabetic ED undergoing penile prosthesis insertion. PKC activator 12,13-phorbol-dibutyrate (PDBu) impaired endothelial relaxations and cGMP generation in response to acetylcholine in the CC from non-diabetic ED. PDBu also impaired responses to a PDE5 inhibitor, sildenafil, in non-diabetic ED patients. Conversely, a PKC inhibitor, GF109203X, improved endothelial, neurogenic, and PDE5-inhibitor-induced relaxations and cGMP generation only in the CC in diabetic ED patients. Endothelial and PDE5-inhibitor-induced vasodilations of PRAs were potentiated only in diabetes. Improvements in endothelial function in diabetes were also achieved with a specific inhibitor of the PKCβ2 isoform or an NADPH-oxidase inhibitor, apocynin, which prevented PDBu-induced impairment in non-diabetic patients. PKC inhibition counteracted NO/cGMP impairment and endothelial dysfunction in diabetes-related ED, potentially improving response to PDE5 inhibition.

Ursodeoxycholic acid ameliorates erectile dysfunction and corporal fibrosis in diabetic rats by inhibiting the TGF-β1/Smad2 pathway.

Corporal tissue fibrosis is critical in diabetes-associated erectile dysfunction. Transforming growth factor-β1/Small mothers against decapentaplegic-2 (TGF-β1/Smad2) contributes to the induction of fibrosis in corporal tissue. Smad7 is accepted as a general negative regulator of Smad signaling, although its role in corporal fibrosis is unknown. Ursodeoxycholic acid (UDCA) is a hydrophilic bile acid used for biliary and liver related disorders and has antifibrotic effects in the liver. This study investigated the effects of UDCA on diabetic erectile dysfunction. Forty-eight male Spraque Dawley rats were divided into six groups: nondiabetic (n = 6), nondiabetic+20 mg/kg UDCA (n = 6), nondiabetic+80 mg/kg UDCA (n = 6), diabetic (n = 10), diabetic+20 mg/kg UDCA (n = 10), diabetic+80 mg/kg UDCA (n = 10). Diabetes was induced by intraperitoneal injection of 60 mg/kg Streptozocin. UDCA (20 and 80 mg/kg/day) or saline was subsequently administered via oral gavage for 56 days. Erectile function was evaluated as measurement of maximum intracavernosal pressure (m-ICP)/mean arterial pressure (MAP) and total ICP/MAP. Corporal tissues were evaluated by Western blotting and Masson's trichrome staining. Electrical stimulation-induced m-ICP/MAP responses were higher in UDCA-treated diabetic rats compared to untreated diabetic rats, respectively (20 mg/kg; 4 V: 0.77 ± 0.11 vs 0.45 ± 0.09, p = 0.0001 and 80 mg/kg; 4 V: 0.78 ± 0.11 vs 0.45 ± 0.09, p = 0.0001) UDCA prevented the increase in phospho-Smad2 and fibronectin protein expressions in diabetic corporal tissue both at 20 mg/kg (p = 0.0002, p = 0.002 respectively) and 80 mg/kg doses (p < 0.0001 for both). Smad7 protein expressions were significantly increased in the UDCA-treated diabetic groups compared to the untreated diabetic group (20 mg/kg: p = 0.0079; 80 mg/kg: p = 0.004). Furthermore, UDCA significantly prevented diabetes-induced increase in collagen (20 mg/kg: p = 0.0172; 80 mg/kg: p = 0.0003) and smooth muscle loss (20 mg/kg: p = 0.044; 80 mg/kg: p = 0.039). In conclusion, UDCA has a potential protective effect on erectile function in diabetic rats by altering fibrotic pathways via inhibition of TGF-β1/Smad2 and activation of Smad7.

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

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. 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. 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 (1-7days) or sham surgery; (2) CN injury and BMP4, GREM1, or mouse serum albumin (control) treatment via Affi-Gel beads or peptide amphiphile (PA) for 14days; (3) 5E1 SHH inhibitor, IgG, or phosphate-buffered saline (control) treatment for 2 to 4days; or (4) CN crush with mouse serum albumin or SHH for 9days. Immunohistochemical and Western analysis for BMP4 and GREM1, and collagen analysis by hydroxyproline and trichrome stain were performed. 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 (1-2days) 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. A better understanding of penile remodeling and how fibrosis occurs with loss of innervation is essential for development of novel ED therapies. The relationship between SHH, BMP4, GREM1, and collagen is complex in the penis. 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.

(064) Argonaute 2 Restores Erectile Function by Enhancing Angiogenesis and Reducing Reactive Oxygen Species Production in Streptozotocin (STZ)-Induced Type-1 Diabetic Mice

Abstract Introduction Diabetes mellitus (DM), a primary cause of erectile dysfunction (ED), is a pancreatic β-cell dysfunction that leads to insulin deficiency and resistance, resulting in microvascular complications. Argonaute 2 (Ago2), a catalytic engine in mammalian RNA interference, is involved in neurovascular regeneration under inflammatory conditions. Objective In the present study, we aimed to determine whether an exogenous injection of Ago2 proteins can improve erectile function in STZ-induced type-1 diabetic mice and explore the specific mechanisms of Ago2 in the process. Methods Eight-week-old male C57BL/6 mice were used for in vivo study. The detailed mechanisms were evaluated in age-matched control or STZ-induced type-1 diabetic mice. Mouse cavernous endothelial cells and human umbilical vein endothelial cells were used for in vitro study. The function of Ago2 in high-glucose condition was evaluated by tube formation assay, migration assay, immunofluorescence stain and western blot experiments. Results We report that Ago2 administration can effectively improve penile erection by enhancing cavernous endothelial cell angiogenesis and survival under diabetic conditions. We found that although Ago2 is highly expressed around blood vessels and nerves, it is significantly reduced in the penis tissue of diabetic mice. Exogenous administration of the Ago2 protein restored erectile function in diabetic mice by reducing reactive oxygen species production-signaling pathways (inducing eNOS Ser1177/NF-κB Ser536 signaling) and improving cavernous endothelial angiogenesis, migration, and cell survival. Our study provides new evidence that Ago2 mediation may be a promising therapeutic strategy and a new approach for diabetic ED treatment. Conclusions Our study provides new insights into Ago2 function and may represent a new therapeutic approach for ED and other vascular and neurological diseases. Disclosure No.

(370) Overview of Nonclinical Studies of LIB-01, a Novel Promising Oral Drug Under Development for Treatment of Erectile Dysfunction

Abstract Introduction LIB-01 is a novel molecule being developed as an oral drug for the treatment of erectile dysfunction (ED). It is a semi-synthetic analog, developed based on research on active compounds identified in root bark that had been used for treatment of male sexual disability since time immemorial. Objective In preparation for clinical development, a number of nonclinical studies on erectile function were conducted in normal and diabetic rats with ED. Studies to investigate the mechanism supporting the pro-erectile effect of LIB-01 were also conducted. A summary of the results from the nonclinical research program is presented. Methods Erectile response elicited by electrical stimulation of the cavernous nerve (ES CN) in anaesthetized rats was assessed. Intracavernous and arterial blood pressures were monitored according to a standardized experimental procedure. Mechanism of action studies were conducted with rat cavernosal tissue samples using immunohistochemistry and in ex vivo/organ chamber experiments. The isometric tension studies were conducted on cavernosal strips from LIB-01 treated and untreated Wistar rats. Cavernosal strips from untreated rats were incubated with either LIB-01 or DMSO (control) and then pre-contracted by phenylephrine (PHE). Concentration- or frequency response curves were performed on PHE pre-contracted strips in 3 consecutive steps: (i) cumulative addition of increasing acetylcholine (ACh) concentrations, (ii) electrical field stimulation (EFS) with increasing frequencies, and (iii), cumulative addition of increasing sodium nitroprusside (SNP) concentrations. Results A statistically significant pro-erectile facilitatory effect of LIB-01 has been repeatedly evidenced in all the studies conducted in anaesthetized control Wistar rats, by oral or subcutaneous administration of LIB-01 at 15 mg/kg/d, with an effect in the similar range as iv sildenafil 0.3mg/kg, when compared. The pro-erectile effect of LIB-01 was not acute, instead, the effect gradually increased and remained for at least 7 days post treatment. In addition, LIB-01 significantly improved erectile responses in anaesthetized diabetic Goto-Kakizaki ED rats compared to vehicle-treated rats, demonstrating the pro-erectile effect of LIB-01 in a robust validated pathophysiological rat model of type 2 diabetes. Immunohistochemistry experiments on cavernosal tissue from LIB-01 treated normal rats showed that neither CD31 nor nNOS expression was altered, thus likely ruling out any effect of LIB-01 on cavernosal micro-vascularization or cavernosal nNOS. Furthermore, only at a high concentration (10-5 M) was there a slight increase in the endothelium dependent relaxations induced by ACh compared to vehicle while LIB-01 did not exert any effect neither on endothelium-independent relaxations induced by SNP nor on nitrergic relaxation induced by EFS of untreated cavernosal strips exposed ex-vivo to different concentrations of LIB-01. Conclusions LIB-01 is a novel molecule which displays a significant pro-erectile effect in anesthetized normal rats as well as in diabetic rats with ED. The pro-erectile effect of LIB-01 is not acute, instead, the effect gradually increases and remains for at least 7 days post-treatment. Results from several mechanistic studies lead to postulate that the mechanism of LIB-01 does not recruit the NO-cGMP pathway thereby differing from phosphodiesterase type 5 inhibitors. A first-in-human clinical trial with LIB-01 is planned to start in 2023. Disclosure Yes, this is sponsored by industry/sponsor: Dicot AB. Clarification: Industry initiated, executed and funded study. Any of the authors act as a consultant, employee or shareholder of an industry for: Dicot AB.

(061) Analysis of BMP4 and GREM1 as Targets of SHH Signaling and Downstream Regulators of the Collagen Axis in the Penis

Abstract Introduction 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). 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. Part of the mechanism of how SHH impacts collagen may involve bone morphogenetic protein four (BMP4) and GREMLIN (GREM1). Microarray analysis identified increased GREM1 (BMP4 antagonist) in corpora cavernosa of ED patients and SHH is a regulator of GREM1 in the limb bud. Objective We will examine 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 (control), prostatectomy and diabetic ED patients was obtained (n=26). Adult Sprague Dawley rats (n=90) underwent either: 1. CN crush (1-7 days) or sham control, 2. CN injury and BMP4, GREM1 or MSA (control) protein treatment via Affi-Gel beads or peptide amphiphile (PA) for 14 days, 3. 5E1 SHH inhibitor, IgG and PBS (controls), or SHH protein treatment for 2-4 days. Immunohistochemical and western analysis for BMP-4 and GREM1, and collagen analysis by hydroxyproline and trichrome stain were performed. Results BMP4 and GREM1 proteins were identified in corpora cavernosal smooth muscle of prostatectomy, diabetic and Peyronie’s patients, and in rat penis, sympathetic nerve fibers, perineurium, blood vessels, and urethra. Collagen decreased 25.4% in rats with CN injury and BMP4 PA treatment (p=0.02) and increased 61.3% with CN injury and GREM1 treatment (p=0.005). Trichrome showed increased collagen in rats treated with GREM1. BMP4 increased smooth muscle. Western 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 BMP4 and GREM1. Aging did not impact BMP4 and GREM1 localization. Conclusions 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. Better understanding of penile remodeling and how fibrosis occurs is essential for development of novel therapies for ED. Disclosure No.