Depression induced by chronic stress leads to penile cavernosal dysfunction: protective effect of anti-TNF-α treatment

Arthritis increases the risk of erectile dysfunction: Results from the NHANES 2001-2004

Objective

This study assessed the association between erectile dysfunction (ED) and arthritis.

Methods

Weighted logistic regression and subgroup analyses were used to investigate the association between arthritis incidence and ED among participants in the 2001-2004 National Health and Nutrition Examination Survey database.

Results

Among the participants, 27.8% and 18.5% had a self-reported history of ED and arthritis, respectively. ED was associated with arthritis (odds ratio [OR]=4.00; 95% confidence interval [CI]: 3.20-4.99; p<0.001], which remained significant after adjustment (OR=1.42, 95% CI: 1.00-1.96; p<0.001). Stratified by type of arthritis, after full adjustment, osteoarthritis remained significant (OR=1.11; 95% CI: 1.03-1.20; p=0.017), and rheumatoid arthritis (OR=1.03, 95% CI: 0.93-1.13; p= 0.5) and other arthritis (OR=1.04, 95% CI: 0.98-1.11; p=0.2) were not significantly correlated with ED. Multiple inference analyses confirmed the robustness of the results.

Conclusion

Our study showed that arthritis was strongly associated with ED. There is an urgent need to raise awareness and conduct additional research on the reasons behind this association in order to implement more scientific and rational treatment programs for patients with ED and arthritis.

The role of gender differences in the outcome of juvenile social isolation: Emphasis on changes in behavioral, biochemical and expression of nitric oxide synthase genes alteration

Social isolation can cause serious problem in performance of individuals in community. As gender differences may cause variation results in the severity of depressive behavior and response of patients to therapy, the impact of gender and the interaction of the level of endocrine secretion in depression were investigated in this study. Wistar rats of both sexes were subjected to post-weaning social isolation (PWSI) conditions and, together with the control group, experienced several behavioral tests including open-field Test (OFT), elevated plus maze (EPM), force swimming test (FST), splash test and novel object recognition test (NOR). Hippocampal tissue was isolated to measure biochemical factors such as nitric oxide level, FRAP amount, MDA level. In addition, real-time-PCR test was used to quantify the genes expression level of inducible nitric oxide synthase (iNOS) and neuronal nitric oxide synthase (nNOS). On the other hand, sexual hormone levels in blood were measured. Both cognitive and behavioral f unctions were declined as the result of PWSI induction in male and diestrus female rats. The consequent surge of estradiol during estrous phase seems to suppress the accumulation of reactive oxygen species (ROS), and modulate iNOS and nNOS expression. In conclusion, while the pattern of PWSI in surge cellular antioxidants, raising cellular ROS level is gender-specific, this alleviation was in relation with the drop of estradiol and unrelated with testosterone level.

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

BACKGROUND

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.

OBJECTIVES

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.

METHODS

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 (50 nmol/kg, every 2 days, 6 times in total) was injected via the tail vein. After 13 weeks, 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, 40 mM) 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.

RESULTS

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.

CONCLUSION

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.

Impact of stress on male fertility: role of gonadotropin inhibitory hormone

Studies have implicated oxidative stress-sensitive signaling in the pathogenesis of stress-induced male infertility. However, apart from oxidative stress, gonadotropin inhibitory hormone (GnIH) plays a major role. The present study provides a detailed review of the role of GnIH in stress-induced male infertility. Available evidence-based data revealed that GnIH enhances the release of corticosteroids by activating the hypothalamic-pituitary-adrenal axis. GnIH also mediates the inhibition of the conversion of thyroxine (T4) to triiodothyronine (T3) by suppressing the hypothalamic-pituitary-thyroidal axis. In addition, GnIH inhibits gonadotropin-releasing hormone (GnRH), thus suppressing the hypothalamic-pituitary-testicular axis, and by extension testosterone biosynthesis. More so, GnIH inhibits kisspeptin release. These events distort testicular histoarchitecture, impair testicular and adrenal steroidogenesis, lower spermatogenesis, and deteriorate sperm quality and function. In conclusion, GnIH, via multiple mechanisms, plays a key role in stress-induced male infertility. Suppression of GnIH under stressful conditions may thus be a beneficial prophylactic and/or therapeutic strategy.

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.

Macrophage-Specific Toll Like Receptor 9 (TLR9) Causes Corpus Cavernosum Dysfunction in Mice Fed a High Fat Diet

BACKGROUND

Erectile dysfunction (ED) has been shown to be related with inflammatory markers in humans. Chronic infusion of TNF-α caused ED in mice while TNF-α knockout mice exhibited improvement in the relaxation of the corpus cavernosum (CC).

AIM

Since obesity triggers an inflammatory process, we aimed to investigate the hypothesis that in obesity, Toll-like receptor 9 (TLR9) activation leads to increased TNF-α levels and impairment in CC reactivity.

METHODS

Four-week old male C57BL6 (WT) and TLR9 mutant (TLR9_MUT) mice were fed a standard chow or high fat diet (HFD) for 12 weeks. Body weight and nonfasting blood glucose were analyzed. Contractile and relaxation responses of the CC were evaluated by electrical field stimulation and concentration response curves to phenylephrine and acetylcholine. Protein expression of nNOS, TNF-α, TNF-R1, TLR9 and MyD88 were measured by western blot. Plasma levels of TNF-α were measured by ELISA.

OUTCOME

In obesity, impaired cavernosal relaxation is associated with the activation of the innate immune system, by increasing the production of TNF-α through the activation of TLR9 in the macrophages.

RESULTS

After 12 weeks of HFD both WT and TLR9_MUT mice had increased body weight and nonfasting blood glucose compared to standard chow. In the CC, acetylcholine-induced relaxation was not changed. A trend to increased contraction to phenylephrine and KCl was seen in WT HFD only. electrical field stimulation-induced relaxation of the CC was decreased in WT HFD as well as nNOS expression in the CC of WT HFD, but not in TLR9_MUT HFD. In the CC, protein expression of TLR9 and MyD88 was similar in all groups. While circulating levels of TNF-α presented only a trend to increase in mice fed HFD, the CC expression of TNF-α was increased only in WT HFD mice.

CLINICAL TRANSLATION

The innate immune system can be a target for the treatment of erectile complications in obesity.

STRENGTHS AND LIMITATIONS

This is the first study demonstrating that activation of TLR9 expressed in macrophages leads to impaired cavernosal relaxation. The main limitation of the study is the lack of understanding about the source/expression of the macrophages in the cavernous tissue. Further, herein, the experiments were performed only in isolated cavernous tissue (in vitro), thus the lack of knowledge on how the TLR9 modulates the in vivo response of the erectile tissue is another limitation of this study.

CONCLUSION

Our findings indicate that CC dysfunction observed in obesity is at least in part mediated by the production of TNF-α upon activation of TLR9 expressed in the macrophages. Priviero F, Calmasini F, Dela Justina V, et al. Macrophage-Specific Toll Like Receptor 9 (TLR9) Causes Corpus Cavernosum Dysfunction in Mice Fed a High Fat Diet. J Sex Med 2021;18:723-731.

The Inflammation Network in the Pathogenesis of Erectile Dysfunction: Attractive Potential Therapeutic Targets

BACKGROUND

Erectile dysfunction (ED) is an evolving health problem in the aging male population. Chronic low-grade inflammation is a critical component of ED pathogenesis and a probable intermediate stage of endothelial dysfunction, especially in metabolic diseases, with the inclusion of obesity, metabolic syndrome, and diabetes.

OBJECTIVE

This review will present an overview of preclinical and clinical data regarding common inflammatory mechanisms involved in the pathogenesis of ED associated with metabolic diseases and the effect of antiinflammatory drugs on ED.

METHODS

A literature search of existing pre-clinical and clinical studies was performed on databases [Pubmed (MEDLINE), Scopus, and Embase] from January 2000 to October 2019.

RESULTS

Low-grade inflammation is a possible pathological role in endothelial dysfunction as a consequence of ED and other related metabolic diseases. Increased inflammation and endothelial/prothrombotic markers can be associated with the presence and degree of ED. Pharmacological therapy and modification of lifestyle and risk factors may have a significant role in the recovery of erectile response through reduction of inflammatory marker levels.

CONCLUSION

Inflammation is the least common denominator in the pathology of ED and metabolic disorders. The inflammatory process of ED includes a shift in the complex interactions of cytokines, chemokines, and adhesion molecules. These data have established that anti-inflammatory agents could be used as a therapeutic opportunity in the prevention and treatment of ED. Further research on inflammation-related mechanisms underlying ED and the effect of therapeutic strategies aimed at reducing inflammation is required for a better understanding of the pathogenesis and successful management of ED.

The near-infrared dye IR-61 restores erectile function in a streptozotocin-induced diabetes model via mitochondrial protection

This study aimed to evaluate the therapeutic effect of IR-61, a novel mitochondrial heptamethine cyanine dye with antioxidant effects, on diabetes mellitus-induced erectile dysfunction (DMED). Eight-week-old male Sprague-Dawley rats were intraperitoneally injected with streptozotocin (STZ) to induce type 1 diabetes. Eight weeks after STZ injection, all rats were divided into three groups: the control group, DM group, and DM + IR-61 group. In the DM + IR-61 group, the rats were administered IR-61 (1.6 mg kg^-1) twice a week by intravenous injection. At week 13, erectile function was evaluated by determining the ratio of the maximal intracavernous pressure to mean arterial pressure, and the penises were then harvested for fluorescent imaging, transmission electron microscopy, histological examinations, and Western blot analysis. Whole-body imaging suggested that IR-61 was highly accumulated in the penis after intravenous injection. IR-61 treatment significantly improved the maximal ICP of diabetic rats. Additionally, IR-61 ameliorated diabetes-induced inflammation, apoptosis, and phenotypic transition of corpus cavernosum smooth muscle cells (CCSMCs) in penile tissue. IR-61 also attenuated mitochondrial damage, reduced reactive oxygen species production in the corpus cavernosum and upregulated sirtuin1 (SIRT1), sirtuin3 (SIRT3), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), and heme oxygenase expression in penile tissue. In conclusion, IR-61 represents a potential therapeutic option for DMED by protecting the mitochondria of CCSMCs, which may be mediated by activation of the SIRT1, SIRT3, and Nrf2 pathways.

Silencing Nogo-B receptor inhibits penile corpus cavernosum vascular smooth muscle cell apoptosis of rats with diabetic erectile dysfunction by down-regulating ICAM-1

Erectile dysfunction (ED) is a major sexual problem for men. Nogo-B receptor (NgBR) has been found to be involved in the regulation of vascular remodeling and angiogenesis. The present study explores the effects of NgBR in penile corpus cavernosum in rats with diabetic ED. Firstly, the ED model of Sprague Dawley rats was established. Hematoxylin-eosin staining and Masson staining were conducted to observe pathological morphology. Immunochemical assay was adopted to detect α-smooth muscle actin (α-SMA), NgBR and intercellular cell adhesion molecule-1 (ICAM-1) expression. Reverse transcription quantitative polymerase chain reaction assay and Western blot analysis were carried out for the assessment of NgBR, factors correlated to ICAM-1, including steroid receptor coactivator (SRC) and proline-rich tyrosine kinase2 (PYK2), and factors associated with apoptosis, including B-cell lymphoma-2 (Bcl-2), Bcl-2 associated protein X (Bax), caspase 3 and cleaved-caspase 3. The results found that capillaries and vascular smooth muscle cell content reduced, and NgBR and ICAM-1 were elevated in rats with diabetic ED. si-NgBR relieved ED by decreasing penile corpus cavernosum smooth muscle systolic percentage and increasing erectile time and rate, intracavernous pressure (ICP)/mean arterial pressure (MAP) and diastolic percentage, improving the pathological changes and inhibiting cavernosum cell apoptosis. si-NgBR also resulted in the down-regulation of ICAM-1 and downstream SRC and PYK2 and promoted α-SMA expression. In conclusion, si-NgBR can provide a potential therapy for diabetic ED in rats by down-regulating ICAM-1, SRC and PYK2, making it a potential therapeutic option for diabetic ED.