The Effects of Calorie Restriction and Exercise on Age-Related Alterations in Corpus Cavernosum

Therapeutic potential of mesenchymal stem cell-derived exosomal miR-296-5p and miR-337-3p in age-related erectile dysfunction via regulating PTEN/PI3K/AKT pathway

Mesenchymal stem cells (MSCs) are viewed as an increasingly promising treatment for age-related erectile dysfunction (AED). Owing to the limitations of injecting living cells, the injection of exosomes appears to be a more plausible option. However, whether MSC-derived exosomes (MSC-Exos) improve AED and their potential mechanism remains unknown. MSC-Exos were prepared and injected intracavernously into aged rats to determine their effects on AED. Masson's trichrome staining was used to ascertain the changes in the histological structure of the corpus cavernosum. Then miRNA sequencing of MSC-Exos and analysis of the critical exosomal miRNAs were performed, as well as their target pathway enrichment analysis. Real-time quantitative PCR (RT-qPCR) and Western blot assay were performed to reveal the functions of MSC-Exos in regulating the PTEN/PI3K/AKT signaling pathway. Moreover, the effects of MSC-Exos on the corpus cavernosum smooth muscle cells (CCSMCs) apoptosis are explored in vitro. The experimental data validate that intracavernous injection of MSC-Exos ameliorated erectile function in AED rats. Masson's trichrome staining shows MSC-Exos therapy restores the histological structure of the corpus cavernosum by improving the ratios of smooth muscle to collagen. The exosomal miR-296-5p and miR-337-3p target and inhibit PTEN, modulating the PI3K/AKT signaling pathway. Furthermore, exosomes inhibit the apoptosis of CCSMCs. Our findings suggest that MSC-Exos improve AED by delivering miR-296-5p and miR-337-3p to regulate the PTEN/PI3K/AKT signaling pathway. These results bode well for the therapeutic potential of MSC-Exos for AED treatment.

The role of microRNAs in erectile dysfunction: From pathogenesis to therapeutic potential

Erectile dysfunction (ED) is a common male sexual dysfunction disease, and it was predicted that the number of ED patients worldwide will reach 322 million by 2025. However, the pathogenesis of ED is complex and the current treatment options are still limited, so it is urgent to explore new treatment strategies. Recent studies have shown that microRNAs (miRNAs) play an important role in ED, and these single-stranded non-coding small RNA molecules are involved in key pathophysiological processes in the occurrence and development of ED. Therefore, miRNAs have remarkable potential as therapeutic targets in ED. Here, this review introduces the physiological basis of erectile function and the pathophysiological changes in ED and summarizes the current knowledge on the expression, biological functions, and molecular mechanisms of miRNAs in ED, especially the potential of miRNA-targeted therapies to improve ED. This review will provide a comprehensive view of the role of miRNAs in the pathogenesis of ED and the potential value of miRNAs in the treatment of ED.

Upregulated IGFBP3 with Aging Is Involved in Modulating Apoptosis, Oxidative Stress, and Fibrosis: A Target of Age-Related Erectile Dysfunction

Aging has been deemed the primary factor in erectile dysfunction (ED). Herein, age-related changes in the erectile response and histomorphology were detected, and the relationship between aging and ED was investigated based on gene expression levels. Thirty male Sprague–Dawley (SD) rats were randomly divided into 6 groups, and intracavernous pressure (ICP) and mean arterial pressure (MAP) were measured. Subsequently, the corpus cavernosum (CC) was harvested and prepared for histological examinations of apoptosis, oxidative stress (OS), and fibrosis. Then, the microarray dataset (GSE10804) was analyzed to identify differentially expressed genes (DEGs) in ED progression, and hub genes were selected. In addition, aged CC smooth muscle cells (CCSMCs) were isolated to evaluate the function of the hub gene by siRNA interference, qRT–PCR, immunofluorescence staining, enzyme-linked immunosorbent assay, western blot analysis, CCK-8 assay, EdU staining, and flow cytometry approaches. The ICP/MAP and smooth muscle cell (SMC)/collagen ratios declined with aging, while apoptosis and OS levels increased with aging. The enriched functions and pathways of the DEGs were investigated, and 15 hub genes were identified, among which IGFBP3 was significantly upregulated. The IGFBP3 upregulation was verified in the CC of aging rats. Furthermore, aged CCSMCs were transfected with siRNA to knock down IGFBP3 expression. The viability and proliferation of the CCSMCs increased, while apoptosis, OS, and fibrosis decreased. Our findings demonstrate that the erectile response of SD rats declines in parallel with enhanced CC apoptosis, OS, and fibrosis with aging. Upregulation of IGFBP3 plays an important role; furthermore, downregulation of IGFBP3 improves the viability and proliferation of CCSMCs and alleviates apoptosis, OS, and fibrosis. Thus, IGFBP3 is a potential therapeutic target for age-related ED.

X-ray micro-computed tomography in the assessment of penile cavernous fibrosis in a rabbit castration model

BACKGROUND

Current assessment methods of penile cavernous fibrosis in animal models have limitations due to the inability to provide complex and volume analysis of fibrotic alterations.

OBJECTIVE

The aim was to evaluate micro-computed tomography (micro-CT) for assessment of cavernous fibrosis and compare it with histological, histochemical, immunohistochemical, and RT-PCR analysis.

MATERIALS AND METHODS

A controlled trial was performed involving 25 New Zealand male rabbits with induced testosterone deficiency by orchidectomy. Penile samples were obtained before and after 7, 14, 21, 84 days from orchidectomy. We consistently performed: a) gray value analysis of corpora cavernosa 3D models reconstructed after micro-CT; b) morphometry of smooth muscles/connective tissue ratio, collagen type I/III ratio, and area of TGF-beta-1 expression in corpora cavernosa; c) RT-PCR of TGF-beta-1 expression.

RESULTS

Micro-CT allowed visualization of penile structures at the resolution comparable to light microscopy. Gray values of corpora cavernosa decreased from 1673 (1512-1773) on the initial day to 1184 (1089-1232) on 21 day (p < 0,005); however, on 84 day, it increased to 1610 (1551-1768). At 21 and 84 days, there were observed a significant decrease in smooth muscle/connective tissue ratio and a significant increase in collagen type I/III ratio (p < 0,05). TGF-beta1 expression increased on 84 day according to immunohistochemistry (p < 0,005). RT-PCR was impossible to conduct due to the absence of RNA in obtained samples after micro-CT.

DISCUSSION AND CONCLUSIONS

Micro-CT provided 3D visualization of entire corpora cavernosa and assessment of radiodensity alterations by gray value analysis in fibrosis progression. We speculate that gray value changes at early and late fibrosis stages could be related to tissue reorganization. RT-PCR is impossible to conduct on tissue samples studied by micro-CT due to RNA destruction. We also suggest that micro-CT could negatively affect the immunohistochemical outcome, as a significant increase of TGF-beta-1 expression occurs later than histological fibrotic signs. This article is protected by copyright. All rights reserved.

Exercise and caloric restriction improve cardiovascular and erectile function in rats with metabolic syndrome

The aim of this study is to examine the possible benefits of exercise and caloric restriction (CR) on cardiovascular hemodynamics, erectile function, and antioxidant system in metabolic syndrome (MS). Sixty male Spraque-Dawley rats were divided into five groups; control, MS, MS + CR, MS + exercise (EXC), and MS + CR + EXC. To induce MS, 10% fructose solution was applied for 3 months. Thereafter, in CR groups calorie was restricted 40% and in EXC groups swimming was performed for 6 weeks. Body weight, blood glucose, and blood pressure (BP) levels were measured before and after MS induction and at the end of the experiment. After decapitation, tumor necrosis factor (TNF)-α, adiponectin (ADP), and plasminogen activator inhibitor (PAI)-1 levels were investigated in blood, oxidative stress parameters were examined in heart, aorta, and corpus cavernosum (CC) tissues. Isometric contraction in isolated tissue bath was studied in aorta and CC tissues. Animals subjected to exercise and CR had decreased BP and blood glucose levels. Impaired contraction-relaxation responses in MS group were improved with exercise and CR. MS-induced increase in TNF-α, PAI-1, malondialdehyde (MDA), and decrease in ADP, glutathione (GSH), and superoxide dismutase (SOD) were normalized with exercise and CR. Exercise and CR may be beneficial against changes in cardiovascular hemodynamics caused by MS.