Sildenafil in postprostatectomy erectile dysfunction (perspective)

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.

Preparation and physicochemical characterization of sildenafil cocrystals

Sildenafil is a specific inhibitor of the phosphodiesterase type 5 (PDE-5) enzyme that protects cyclic guanosine monophosphate from breakdown by PDE-5. It is a biopharmaceutical categorization system Class II medication with low bioavailability because it is almost insoluble in water. The objectives of this study were to prepare sildenafil cocrystals with co-former molecules including aspirin (acetylsalicylic acid [ASA]), fumaric acid (FMA), and benzoic acid (BZA) to improve the water solubility of sildenafil. The cocrystals were prepared by antisolvent addition (AA) and slow solvent evaporation (SE) methods. The stoichiometric ratios of sildenafil and co-former molecules were varied. The obtained crystals were characterized by stereomicroscope, Fourier transformed infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), and powder X-ray diffraction (PXRD). The water solubility of sildenafil cocrystals was compared with sildenafil base. In the AA method, the crystals only form in sildenafil-ASA reaction. These crystals were not cocrystals between sildenafil and ASA because they were formed to new substances that were confirmed by single-crystal X-ray diffraction. In the SE method, the cocrystals were successfully prepared in the reaction of sildenafil with ASA, FMA, and BZA which use acetone or ethyl acetate as a solvent. The obtained crystals are irregular shapes and their FT-IR, NMR, and PXRD results exhibited the characteristics of sildenafil and its co-former. The stoichiometric ratios of sildenafil and co-formers after cocrystallization were different from an initial of crystallization. The sildenafil cocrystals with ASA, FMA, and BZA by SE method had higher water solubility than sildenafil base. The sildenafil-FMA cocrystals had the highest water solubility and increased up to five times when compared with sildenafil base.

Whole-transcriptome analysis of rat cavernosum and identification of circRNA-miRNA-mRNA networks to investigate nerve injury erectile dysfunction pathogenesis

There is growing evidence that circular RNAs (circRNAs) play a vital role in many kinds of diseases, including erectile dysfunction (ED). Nevertheless, the role of circRNAs in cavernous nerve-damaging ED (CNI-ED) is unknown. Here, we aimed to discover novel circRNAs, probed their potential role in the CNI-ED, and construct a ceRNA network of circRNAs. Twelve male Sprague Dawley rats were randomly divided into 2 groups by us: bilateral cavernous nerve crush (BCNC) and control groups. Four weeks after surgery, the spongy smooth muscle tissue of the rat penis was sequenced using high-throughput full transcriptome sequencing. We analyzed the expression of circRNAs, miRNAs, and mRNAs in the two groups. Twenty circRNAs with significantly different expressions were selected for RT-qPCR. CeRNA network of circRNAs was established using Cytoscape. GO and KEGG analysis was done by R package. Sequencing showed that 4,587 circRNAs, 762 miRNAs, and 21,661 mRNAs were dysregulated in the BCNC group. The top 20 differentially expressed circRNAs were further verified via RT-qPCR. The ceRNA network contained ten circRNAs, six miRNAs, and 227 mRNAs, including 23 circRNA-miRNA pairs and 227 miRNA-mRNA pairs. GO and KEGG analysis suggested that these ten circRNAs could main regulate energy metabolism processes. A protein‐protein interaction network was constructed with the mRNAs in ceRNA network, and five hub genes were identified. Our study revealed a potential link between circRNAs, miRNAs, and mRNAs in CNI-ED, suggesting that circRNAs may contribute to the occurrence of ED by regulating the cellular energy metabolism in CNI-ED.

Enhanced effects of salidroside on erectile function and corpora cavernosa autophagy in a cavernous nerve injury rat model

We explored the efficacy and mechanisms of salidroside treatment for erectile dysfunction induced by bilateral cavernous nerve injury (BCNI). Forty male rats were divided into four groups as follows: sham (cavernous nerves exposed only) (S); BCNI (M); BCNI + rapamycin (M + rapamycin); and BCNI + salidroside (M + salidroside). Erectile function in the rats was measured by intracavernosal pressure. Penile tissue was harvested for transmission electron microscopy, immunohistochemistry, immunofluorescence, Masson's trichrome staining, haematoxylin-eosin staining, TdT-mediated dUTP Nick End Labeling and western blotting. The M group exhibited a decrease in erectile responses and increased apoptosis and fibrosis compared to these in the S group. Meanwhile, nerve content and the penile atrophy index were also decreased in the M group. Treatment with salidroside and rapamycin for 3 weeks partially restored erectile function and significantly attenuated corporal apoptosis, fibrosis, nerve content and penile atrophy in the M group. Moreover, the autophagy level was further enhanced in the M + salidroside group, which was the same as that in the positive observation group (M + rapamycin). Salidroside treatment not only improved erectile function in rats with BCNI, but also inhibited apoptosis and fibrosis and ameliorated the loss of nerve content and endothelial and corpus cavernosum smooth muscle cells by promoting protective autophagy.

Global Research Trends on Prostate Diseases and Erectile Dysfunction: A Bibliometric and Visualized Study

Objectives

To identify the cooperation of authors, countries, institutions and explore the hot topics’ prospects regarding research of prostate diseases and erectile dysfunction (ED).

Methods

Publications on research of prostate diseases and ED were retrieved from the Web of Science Core Collection (WoSCC). Bibliometric analyses were performed using VOSviewer and CiteSpace software. Network maps were generated to evaluate the collaborations between different authors, countries, institutions, and keywords.

Results

A total of 2,599 articles related to study of prostate diseases and ED were identified. We observed gradually increasing in the number of publications from 1998 to 2016, and the trend was to be relatively stable in the past 3 years. Journal of Sexual Medicine (243 papers) owned the highest number of publications and Journal of Urology was the most co-cited journal. Mulhall John P (52 papers) was the top most productive authors and Mcvary Kebin T with the largest numbers of citations (1,589 co-citations) during the past decades. There were active collaborations among the top authors. The USA was the leading contributor in this field with 1,078 papers. Active cooperation between countries and between institutions was observed. The main hot topics included matters related to erectile dysfunction, prostate cancer, quality-of-life, radical prostatectomy, sexual function, and BPH.

Conclusion

Bibliometric analysis provides a comprehensive overview of the development of scientific literature, allowing relevant authors and research teams to recognize the current research status in this field and at the same time provide a reference for formulating future research directions.