The two phases of the clinical validation of preclinical translational mechanistic research on PDE5 inhibitors since Viagra's advent. A personal perspective

Daily low-dose tadalafil may reduce the penile curvature progression rate in patients with acute Peyronie's disease: a retrospective comparative analysis

The aim of this study was to evaluate the clinical outcomes of patients in acute phase of Peyronie's disease (PD) treated with daily low-dose of Tadalafil. An observational retrospective study involving patients in acute phase of PD with erectile dysfunction (ED) was designed. All subjects were offered Tadalafil 5 mg one tablet a day. Men who accepted treatment were compared to patients who refused Tadalafil. Penile curvature progression was chosen as the primary outcome. PD Questionnaire (PDQ) and IIEF-5 scores were selected as secondary outcomes. A total of 191 patients were included in the study (108 intervention vs. 83 control). Penile curvature progression rate was significantly lower in subjects taking Tadalafil at 12 weeks (25.9% vs. 39.7%, p = 0.042). Mean IIEF-5 score improved in the intervention group, becoming significantly higher compared to the observation group at 12 weeks (19.3 vs. 11.2 points, p < 0.001). Mean PDQ-Overall and PDQ-Penile Pain scores only improved in the intervention group and the statistically significant differences at baseline between groups became not statistically significant at 12 weeks (p = 0.001 vs. p = 0.232 and p < 0.001 vs. p = 0.078, respectively). Daily low-dose Tadalafil in patients with acute phase of PD seems to significantly reduce the penile curvature progression rate compared to observation, especially when it is administrated early. It also appears to improve erectile function and PD-related symptoms.

Caveolin-1 scaffolding domain peptide prevents corpus cavernosum fibrosis and erectile dysfunction in bilateral cavernous nerve injury-induced rats

BACKGROUND

Corpus cavernosum (CC) fibrosis significantly contributes to post-radical prostatectomy erectile dysfunction (pRP-ED). Caveolin-1 scaffolding domain (CSD)-derived peptide has gained significant concern as a potent antagonist of tissue fibrosis. However, applying CSD peptide on bilateral cavernous nerve injury (BCNI)-induced rats remains uninvestigated.

AIM

The aim was to explore the therapeutic outcome and underlying mechanism of CSD peptide for preventing ED in BCNI rats according to the hypothesis that CSD peptide may exert beneficial effects on erectile tissue and function following BCNI through limiting collagen synthesis in CC smooth muscle cells (CCSMCs) and CC fibrosis.

METHODS

After completing a random assignment of male Sprague Dawley rats (10 weeks of age), BCNI rats received either saline or CSD peptide treatment, as opposed to sham-operated rats. The evaluations of erectile function (EF) and succedent collection and histological and molecular biological examinations of penile tissue were accomplished 3 weeks postoperatively. In addition, the fibrotic model of CCSMCs was used to further explore the mechanism of CSD peptide action in vitro.

OUTCOMES

The assessments of EF, SMC/collagen ratio, α-smooth muscle actin, caveolin-1 (CAV1), and profibrotic indicators expressions were conducted.

RESULTS

BCNI rats exhibited significant decreases in EF, SMC/collagen ratio, α-SMA, and CAV1 levels, and increases in collagen content together with transforming growth factor (TGF)-β1/Smad2 activity. However, impaired EF, activated CC fibrosis, and Smad2 signaling were attenuated after 3 weeks of CSD peptide treatment in BCNI rats. In vitro, TGF-β1-induced CCSMCs underwent fibrogenetic transformation characterized by lower expression of CAV1, higher collagen composition, and phosphorylation of Smad2; then, the delivery of CSD peptide could significantly block CCSMC fibrosis by inactivating Smad2 signaling.

CLINICAL IMPLICATIONS

Based on available evidence of CSD peptide in the prevention of ED in BCNI rats, this study can aid in the development and clinical application of CSD peptide targeting pRP-ED.

STRENGTHS AND LIMITATIONS

This study provides data to suggest that CSD peptide protects against BCNI-induced deleterious alterations in EF and CC tissues. However, the available evidence still does not fully clarify the detailed mechanism of action of CSD peptide.

CONCLUSION

Administration of CSD peptide significantly retarded collagen synthesis in CCSMCs, limited CC fibrosis, and prevented ED via confrontation of TGF-β1/Smad signaling in BCNI rats.

Gosha-Jinki-Gan Improved Erectile Dysfunction Caused by Anti-Cancer Agent Oxaliplatin by Decreasing Transcriptional Expression of Phosphodiesterase-5 in Rats

Background

A platinum-containing anti-cancer agent, oxaliplatin (L-OHP), is known to induce peripheral neuropathy, including erectile dysfunction (ED) as a side effect, while Gosha-jinki-gan (GJG) is a traditional Japanese herbal medicine mainly used for peripheral neuropathy.

Aim

To investigate the effect of GJG on L-OHP-induced ED in rats.

Methods

Twelve-week-old male Wister/ST rats were categorized into the following groups: Sham, Sham+GJG, L-OHP, and L-OHP+GJG (each n = 10). The L-OHP and L-OHP+GJG groups were injected intravenously with L-OHP (4 mg/kg) for 2 consecutive days in the first week. Statistical significance was determined using Bonferroni's multiple comparison test.

Outcomes

At the end of the study period, erectile function was evaluated by measuring intracavernosal pressure (ICP) and mean arterial pressure (MAP) after cavernous nerve stimulation. Western blot analysis was used to assess the neuronal nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS) levels, and quantitative polymerase chain reaction was used to assess the expression of phosphodiesterase-5 (PDE-5) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-1.

Results

The ICP/MAP ratio of L-OHP rats (0.34 ± 0.06) was significantly lower than that of Sham rats (0.67 ± 0.03, P < .01), however, the ICP/MAP ratio of L-OHP+GJG rats (0.55 ± 0.01) was significantly higher than that of L-OHP rats (P < .01). There were no significant differences in the nNOS and eNOS protein expression between both groups (P > .05). GJG administration significantly decreased PDE-5 and NADPH oxidase-1 messenger RNA expressions in the L-OHP+GJG group.

Clinical Translation

This animal model study suggests that GJG might be effective for erectile function in cancer survivors.

Strengths & limitations

Our study identified that GJG had no notable side effects in the treated group. Further investigation of the cavernous nerve would also help elucidate the mechanism of GJG effect, which is a limitation of this study.

Conclusion

We found that GJG administration improved L-OHP-induced ED by improving transcriptional PDE-5 expression.

Kataoka T, Kawaki Y, Kito Y, et al. Gosha-Jinki-Gan Improved Erectile Dysfunction Caused by Anti-Cancer Agent Oxaliplatin by Decreasing Transcriptional Expression of Phosphodiesterase-5 in Rats. Sex Med 2022;10:100484.

Comparison of critical biomarkers in 2 erectile dysfunction models based on GEO and NOS-cGMP-PDE5 pathway

BACKGROUND

Erectile dysfunction is a disease commonly caused by diabetes mellitus (DMED) and cavernous nerve injury (CNIED). Bioinformatics analyses including differentially expressed genes (DEGs), enriched functions and pathways (EFPs), and protein-protein interaction (PPI) networks were carried out in DMED and CNIED rats in this study. The critical biomarkers that may intervene in nitric oxide synthase (NOS, predominantly nNOS, ancillary eNOS, and iNOS)-cyclic guanosine monophosphate (cGMP)-phosphodiesterase 5 enzyme (PDE5) pathway, an important mechanism in erectile dysfunction treatment, were then explored for potential clinical applications.

METHODS

GSE2457 and GSE31247 were downloaded. Their DEGs with a |logFC (fold change)| > 0 were screened out. Database for Annotation, Visualization and Integrated Discovery (DAVID) online database was used to analyze the EFPs in Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes networks based on down-regulated and up-regulated DEGs respectively. PPI analysis of 2 datasets was performed in Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and Cytoscape. Interactions with an average score greater than 0.9 were chosen as the cutoff for statistical significance.

RESULTS

From a total of 1710 DEGs in GSE2457, 772 were down-regulated and 938 were up-regulated, in contrast to the 836 DEGs in GSE31247, from which 508 were down-regulated and 328 were up-regulated. The 25 common EFPs such as aging and response to hormone were identified in both models. PPI results showed that the first 10 hub genes in DMED were all different from those in CNIED.

CONCLUSIONS

The intervention of iNOS with the hub gene complement component 3 in DMED and the aging process in both DMED and CNIED deserves attention.

Extracorporeal Shock Wave Therapy in Peyronie's Disease: Clinical Efficacy and Safety from a Single-Arm Observational Study

Purpose

In this study, we aimed to determine the role of extracorporeal shockwave therapy (ESWT) in the management of Peyronie's disease (PD).

Materials and Methods

A total of 325 patients suffering from PD were enrolled in this single-arm clinical study. All patients were received ESWT using a schedule of 1 treatment/wk. Penile curvature was measured by a goniometer after intracavernosal drug-induced erection using Alprostadil. Plaque size was measured with a ruler and sexual function assessed by the international index of erectile function (IIEF)-15 score. Severity of erectile dysfunction was classified as severe (IIEF-15 ≤10), moderate (IIEF-15 between 11 and 16), or mild (IIEF-15 between 17 and 25). Results were evaluated at baseline and 3 months after the treatment.

Results

All the patients completed the study protocol. Median age was 59.0 years (55.0–64.0 years). After treatment, the median (interquartile range, IQR) plaque size reduced from 1.78 cm² (1.43–2.17 cm²) to 1.53 cm² (1.31–1.96 cm²) (p<0.001); the median (IQR) penile length in erection increased from 13.0 cm (12.0–14.0 cm) to 14 cm (13.0–15.0 cm) (p<0.001) and the median (IQR) penile curvature from 30.4° (22.2°–35.4°) to 25.0° (20.2°–30.4°) (p<0.001). We also observed a decrease in pain assessed by visual analogue scale (7 vs. 3; p<0.001), an improvement in each of the IIEF sub-domains (p<0.001) and an improvement in all three PD questionnaire domains (p<0.001).

Conclusions

Based on our findings, ESWT could be considered a safe and efficient minimally invasive option for the management of the patients suffering from PD.