Phosphodiesterase-5 inhibitors for erectile dysfunction in patients with diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

Hormonal regulation in diabetes: Special emphasis on sex hormones and metabolic traits

Diabetes constitutes a significant global public health challenge that is rapidly reaching epidemic proportions. Among the non-communicable diseases, the incidence of diabetes is rising at an alarming rate. The International Diabetes Federation has documented a 9.09% prevalence of diabetes among individuals aged between 20 and 79 years. The interplay of gonadal hormones and gender differences is critical in regulating insulin sensitivity and glucose tolerance, and this dynamic is particularly crucial because of the escalating incidence of diabetes. Variations in insulin sensitivity are observed across genders, levels of adiposity, and age groups. Both estrogen and testosterone are seen to influence glucose metabolism and insulin sensitivity. This chapter surveys the present knowledge of sex differences, sex hormones, and chromosomes on insulin imbalance and diabetes development. It further highlights the influence of metabolic traits in diabetes and changes in sex hormones during diabetic pregnancy. Notably, even stressful lifestyles have been acknowledged to induce hormonal imbalances. Furthermore, it discusses the potential of hormonal therapy to help stabilize sex hormones in diabetic individuals and focuses on the most recent research investigating the correlation between sex hormones and diabetes.

A Review of Antidiabetic Medicinal Plants as a Novel Source of Phosphodiesterase Inhibitors: Future Perspective of New Challenges Against Diabetes Mellitus

Intracellular glucose concentration plays a crucial role in initiating the molecular secretory process of pancreatic β-cells through multiple messengers and signaling pathways. Cyclic nucleotides are key physiological regulators that modulate pathway interactions in β -cells. An increase of cyclic nucleotides is controled by hydrolysed phosphodiesterases (PDEs), which degrades cyclic nucleotides into inactive metabolites. Despite the undeniable therapeutic potential of PDE inhibitors, they are associated with several side effects. The treatment strategy for diabetes based on PDE inhibitors has been proposed for a long time. Hence, the world of natural antidiabetic medicinal plants represents an ideal source of phosphodiesterase inhibitors as a new strategy for developing novel agents to treat diabetes mellitus. This review highlights medicinal plants traditionally used in the treatment of diabetes mellitus that have been proven to have inhibitory effects on PDE activity. The contents of this review were sourced from electronic databases, including Science Direct, PubMed, Springer Link, Web of Science, Scopus, Wiley Online, Scifinder and Google Scholar. These databases were consulted to collect information without any limitation date. After comprehensive literature screening, this paper identified 27 medicinal plants that have been reported to exhibit anti-phosphodiesterase activities. The selection of these plants was based on their traditional uses in the treatment of diabetes mellitus. The review emphasizes the antiphosphodiesterase properties of 31 bioactive components derived from these plant extracts. Many phenolic compounds have been identified as PDE inhibitors: Brazilin, mesozygin, artonin I, chalcomaracin, norartocarpetin, moracin L, moracin M, moracin C, curcumin, gallic acid, caffeic acid, rutin, quercitrin, quercetin, catechin, kaempferol, chlorogenic acid, and ellagic acid. Moreover, smome lignans have reported as PDE inhibitors: (+)-Medioresinol di-O-β-d-glucopyranoside, (+)- Pinoresinol di-O-β-d-glucopyranoside, (+)-Pinoresinol-4-O-β-d-glucopyranosyl (1→6)-β-dglucopyranoside, Liriodendrin, (+)-Pinoresinol 4'-O-β-d-glucopyranoside, and forsythin. This review provides a promising starting point of medicinal plants, which could be further studied for the development of natural phosphodiesterase inhibitors to treat diabetes mellitus. Therefore, it is important to consider clinical studies for the identification of new targets for the treatment of diabetes.

Gaps in the management of diabetes in Asia: A need for improved awareness and strategies in men's sexual health

Sexual dysfunction, which is defined as 'difficulty during any stage of the sexual encounter that prevents or impairs the individual or couple from enjoying sexual activity', is globally prevalent in males with prediabetes and diabetes. It is an early harbinger of cardiovascular diseases and has a profound impact on one's physical, mental, and social health. Among patients with either prediabetes or diabetes, the most common male sexual dysfunctions are hypogonadism, erectile dysfunction, and premature ejaculation. In Asia, although sexual health is an important factor of men's health, it is rarely discussed freely in real-life practice. Addressing sexual health in Asian males has always been challenging with multiple barriers at the levels of patients and health care providers. Therefore, the assessment and management of sexual dysfunction in routine clinical practice should involve a holistic approach with effective patient-provider communication. In this review, we discuss the epidemiology, pathophysiology, and the management of hypogonadism, erectile dysfunction, and premature ejaculation among males with either prediabetes or diabetes (type 1 and type 2), as well as the evidence gaps across Asia.

Ameliorative Sexual Behavior and Phosphodiesterase-5 Inhibitory Effects of Spondias mangifera Fruit Extract in Rodents: In Silico, In Vitro, and In Vivo Study

The ethanolic extracts of Spondias mangifera fruit (SMFE) were evaluated for aphrodisiac activity. The in-vitro phosphodiesterase-5 (PDE-5) inhibition was assessed based on in-silico molecular docking and simulation studies. In addition, the in-vivo sexual behavior was analyzed in the form of mount (MF, ML), intromission (IF, IL), and ejaculation (EF, EL) frequencies and latencies to validate the in-vitro results. Some biochemical parameters, including PDE-5, nitric oxide, and testosterone, were also observed. The above extract constituted β-amyrin, β-sitosterol, and oleanolic acid and showed tremendous binding with phosphodiesterase-5 and sildenafil. Both the sildenafil and ethanolic extracts (200 and 400 mg/kg/d bodyweight) significantly (p < 0.1, p < 0.05) increased MF, IF, and EF, respectively. In contrast, ML and IL significantly (p < 0.1) decreased, and EL significantly (p < 0.1) increased compared with a normal group of animals. The ethanolic extracts (200 and 400 mg/kg/d bodyweight) and sildenafil further significantly (p < 0.05, p < 0.1) diminished PDE-5 activity significantly (p < 0.05, p < 0.1) and enhanced nitric oxide and testosterone levels, as compared with normal rodents. Therefore, the S. mangifera ethanolic extract might be a valuable alternate aphrodisiac for erectile dysfunction.

Erectile dysfunction and diabetes: A melting pot of circumstances and treatments

Diabetes mellitus (DM), a chronic metabolic disease characterised by elevated levels of blood glucose, is among the most common chronic diseases. The incidence and prevalence of DM have been increasing over the years. The complications of DM represent a serious health problem. The long-term complications include macroangiopathy, microangiopathy and neuropathy as well as sexual dysfunction (SD) in both men and women. Erectile dysfunction (ED) has been considered the most important SD in men with DM. The prevalence of ED is approximately 3.5-fold higher in men with DM than in those without DM. Common risk factors for the development of DM and its complications include sedentary lifestyle, overweight/obesity and increased caloric consumption. Although lifestyle changes may help improve sexual function, specific treatments are often needed. This study aims to review the definition and prevalence of ED in DM, the impact of DM complications and DM treatment on ED and, finally, the current and emerging therapies for ED in patients with DM.

Does Treatment of Erectile Dysfunction With PDE 5 Inhibitor Tadalafil Improve Quality of Life in Male Patients With Compensated Chronic Liver Disease? A Prospective Pilot Study

BACKGROUND AND AIMS

Erectile dysfunction (ED) is common in patients with compensated cirrhosis but its impact on the quality of life (QOL) is usually overlooked. This study aimed at determining the frequency of ED in male patients with compensated chronic liver disease (CLD), assessing their QOL and the response to treatment with tadalafil. A secondary aim was to assess the effect of the tadalafil therapy on liver fibrosis, if any.

METHODS

Consecutive patients with compensated CLD and advanced liver fibrosis were screened at the baseline with the International Index of Erectile Function-5 (IIEF-5), QOL questionnaire (WHOQOL-BREF), liver stiffness measurements (LSM) made with Fibroscan™ (Echosens, France), and fibrosis index based on 4 factors (FIB-4) scores. Patients with ED meeting eligibility criteria were prescribed PDE5 inhibitor tadalafil 20 mg on alternate days. During the follow-up, IIEF-5, LSM, and FIB-4 were monitored after 3 and 6 months while the WHOQOL-BREF questionnaire was administered at the baseline and at 6 months.

RESULTS

Among 89 patients with CLD and advanced liver fibrosis, ED was present in 43 (48%) and tadalafil was prescribed to 34 patients (38%) meeting exclusion and inclusion criteria. At 3 months follow-up, the mean IIEF 5 score increased from 15.57 ± 4 to 20.78 ± 3.6, (P = 0.0001) and the improvement persisted at 6 months (IIEF-5 score 21.87 ± 2.2; P = 0.12). The physical, social relationships, and environment domains in the WHOQOL-BREF questionnaire showed significant improvement at six months (P < 0.05) but not the psychological domain (P = ns). From a baseline value of 12.69 ± 3.1 kPa, the mean LSM decreased to 11.37 ± 3.9 kPa, (P = 0.02) after 3 months on tadalafil. After 6 months, the LSM further decreased from 11 ± 0.9 to 8.2 ± 3.2 kPa (P = 0.034). FIB-4 values showed a decline from the baseline at 3 months, from 1.52 ± 0.58 to 1.32 ± 0.55, P < 0.05 and at 6 months, from 1.25 ± 0.53 to 0.97 ± 0.36, P > 0.05. The CAP values did not show any significant change. There was an insignificant decline in the SGOT and SGPT levels (P > 0.05) with no significant change in CTP or MELD scores.

CONCLUSIONS

In the short term, tadalafil improves ED and QOL in patients with CLD and advanced liver fibrosis. It may also reduce liver fibrosis in them. Further studies that include liver histology are needed to confirm this preliminary observation of a possible antifibrotic effect.

Effects of Stem Cell Therapy on Diabetic Mellitus Erectile Dysfunction: A Systematic Review and Meta-analysis

BACKGROUND

Stem cell is considered a potential therapy for treating erectile dysfunction (ED), including diabetic mellitus erectile dysfunction (DMED), which was investigated in some preclinical studies. Several trials introduced stem cell into clinical practice, but divergences emerged.

AIM

To further investigate the therapeutic effects of stem cell on DMED in preclinical studies and investigate some possible factors that influence curative effects.

METHODS

The literature research was conducted in Web of Science and PubMed to retrieve studies utilizing stem cell to treat DMED. Revman 5.3 was used to perform subgroup analysis of intracavernosal pressure/mean artery pressure (ICP/MAP) and structural changes. Publication bias was assessed with Egger's test, funnel plot, and sensitivity analysis by Stata 15.0.

OUTCOMES

The ICP/MAP and structural changes before and after stem cell treatment.

RESULTS

Of 2,115 studies retrieved, 23 studies are eligible. Plus 10 studies from a meta-analysis published in 2016, 33 studies were enrolled. Pooled analysis showed that stem cell ameliorates damaged ICP/MAP (WMD 0.26; 95% CI 0.23-0.29; P < .001) and structural changes induced by diabetes. Subgroup analysis indicated that adipose-derived mesenchymal stem cell (ADSC) may have better efficacy than bone marrow-derived mesenchymal stem cell (BMSC) (χ2= 4.21, P = .04; ADSC WMD 0.28, 95% CI [0.24-0.32] vs BMSC WMD 0.22 95% CI [0.17-0.26]). Transplantation type, diabetes type, and cell number make no difference to curative effects. Gene modification and therapy combination proved promising in improving the therapeutic effects of stem cell.

CLINICAL TRANSLATION

The evidence reminded that ADSC may be prior to BMSC in clinical trials and autotransplantation is probably not compulsory in the clinical practice of stem cell.

STRENGTHS AND LIMITATIONS

The study number and sample size are large enough. However, high degree of heterogeneity remains after subgroup analysis.

CONCLUSION

This meta-analysis suggests the efficacy of stem cell therapy for DMED and the possible superiority of ADSC over BMSC in erection restoration and structure renovation.

Medicinal plants as a potential source of Phosphodiesterase-5 inhibitors: A review

ETHNOPHARMACOLOGICAL RELEVANCE

The prevalence and distress caused by erectile dysfunction (ED) to both male and female partners are increasing at a steady rate. ED has now become the most treated sexual disorder for men among young and old age groups due to varying physical and psychological factors. The treatment with synthetic Phosphodiesterase-5 (PDE5) inhibitors are cost-effective but due to adverse effects such as priapism, loss of vision, heart attack and syncope, the daily life patterns of these patients are distressed and hence the need for alternative medicaments or sources are of utmost important. Therefore, the exploration of medicinal plants as PDE5 inhibitors will be worthwhile in tackling the problems as many plant extracts and fractions have been long used as aphrodisiacs and sexual stimulants which may be found to be active against PDE5 enzyme.

AIM OF THE STUDY

To provide a review on the different medicinal herbs traditionally used as natural aphrodisiacs, libido or sexual enhancers which are proven for their PDE5 inhibitory effect.

MATERIALS AND METHODS

Ethnobotanical and scientific information was procured, reviewed and compiled from the literature search of electronic databases and search engines.

RESULTS

A total of 97 medicinal plants exhibiting PDE5 inhibitory effect are reviewed in this paper which is supported by preclinical experimental evidence. Among them, 77 plants have been selected according to their traditional and ethnobotanical uses as aphrodisiacs and the rest are screened according to their effectiveness against predisposing factors responsible for ED and sexual dysfunction such as diabetes and hypertension or due to the presence of phytochemicals having structural similarity towards the identified natural PDE5 inhibitors. In addition, sixteen alkaloids, sixty-one phenolics and eight polycyclic aromatic hydrocarbons have been isolated or identified from active extracts or fractions that are exhibiting PDE5 inhibitory activity. Among them, isoflavones and biflavones are the major active constituents responsible for action, where the presence of prenyl group for isoflavones; and the methoxy group at C-5 position of flavones are considered essential for the inhibitory effect. However, the prenylated flavonol glycoside, Icariin and Icariside II isolated from Epimedium brevicornum Maxim (hory goat weed) are the most effective inhibitor, till date from natural sources. Traditional medicines or formulations containing extracts of Ginkgo biloba L., Kaempferia parviflora Wall. ex Baker, Clerodendrum colebrookianum Walp., Eurycoma longifolia Jack and Vitis vinifera L. are also found to be inhibitors of PDE5 enzyme.

CONCLUSION

The review suggests and supports the rational use of traditional medicines that can be further studied for the development of potential PDE5 inhibitors. Many traditional medicines are still used in various regions of Africa, Asia and South America that are poorly characterized and experimented. Despite the availability of a vast majority of traditional formulations as aphrodisiacs or sexual stimulants, there exists a need for systemic evaluation on the efficacy as well as the mechanism of action of the herbal constituents for the identification of novel chemical moieties that can be further developed for maximum efficacy.

LncRNA MALAT1 facilitates BM-MSCs differentiation into endothelial cells via targeting miR-206/VEGFA axis

Bone marrow-derived mesenchymal stem cells (BM-MSCs) implantation shows a repair effect on erectile function in diabetes mellitus-induced erectile dysfunction (DMED) due to its differentiative capacity into endothelial cells (ECs) that contributes to endothelial repair. This study was designed to explore the functional role and mechanism of long noncoding RNA (lncRNA)-metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in BM-MSCs-mediated DMED repairing. The DMED rat model was established and the erectile function was evaluated by calculating the intracavernous pressure (ICP)/mean arterial pressure (MAP) ratio in the DMED models with or without BM-MSCs implantation. The differentiation of BM-MSCs toward ECs was assessed by measuring the expression of EC-specific genes. RNA pull-down and luciferase reporter assay were performed to explore the interaction between miR-206 and MALAT1 or VEGFA. BM-MSCs implantation improved the erectile function of DMED rats and increased MALAT1 expression. MALAT1 was time-dependently upregulated during the VEGF-induced BM-MSCs differentiation into ECs. Mechanistically, MALAT1 acted as a sponge of miR-206 to upregulate VEGFA expression, thereby promoting the differentiation of BM-MSCs into ECs. Moreover, MALAT1 silencing in vivo impaired the repairing effect of BM-MSCs on erectile dysfunction. Collectively, MALAT1 facilitates BM-MSCs differentiation into ECs via regulating miR-206/VEGFA axis.

The treatment rate of erectile dysfunction (ED) in younger men with type 2 diabetes is up to four times higher than the equivalent non-diabetes population

INTRODUCTION

Erectile dysfunction (ED) is common in older age and in diabetes mellitus (DM). Phosphodiesterase type 5-inhibitors (PDE5-is) are the first-line for ED. We investigated how the type of diabetes and age of males affect the PDE5-i use in the primary care setting.

METHODS

From 2018 to 2019, the general practice level quantity of all PDE5-i agents was taken from the general practice (GP) Prescribing Dataset in England. The variation in outcomes across practices was examined across one year, and for the same practice against the previous year.

RESULTS

We included 5761 larger practices supporting 25.8 million men of whom 4.2 million ≥65 years old. Of these, 1.4 million had T2DM, with 0.8 million of these >65. About 137 000 people had T1DM. About 28.8 million tablets of PDE5-i were prescribed within the 12 months (2018-2019) period in 3.7 million prescriptions (7.7 tablets/prescription), at total costs of £15.8 million (£0.55/tablet). The NHS ED limit of one tablet/user/wk suggests that 540 000 males are being prescribed a PDE5-i at a cost of £29/y each. With approximately 30 000 GPs practising, this is equivalent to one GP providing 2.5 prescriptions/wk to overall 18 males. There was a 3x variation between the highest decile of practices (2.6 tablets/male/y) and lowest decile (0.96 tablets/male/y). The statistical model captured 14% of this variation and showed that T1DM males were the largest users, while men age <65 with T2DM were being prescribed four times as much as non-DM. Those T2DM >65 were prescribed 80% of the non-DM amount.

CONCLUSION

There is a wide variation in the use of PDE5-is. With only 14% variance capture, other factors including wide variation in patient awareness, prescribing rules of local health providers, and recognition of the importance of male sexual health by GP prescribers might have a significant impact.

The good, bad, and the ugly of regenerative therapies for erectile dysfunction

Erectile dysfunction (ED) is a common condition which reduces quality of life of both patients and their partners, and is a significant health care expense every year. Although phosphodiesterase type-5 inhibitors are the current first-line treatment for men with ED, they are limited by their on-demand dosing, intolerance, and variable efficacy in complex patient populations such as men with multiple medical comorbidities or ED after pelvic surgery. Regenerative medicine has been introduced and investigated in andrology as an encouraging strategy to restore diseased erectile tissue structure and function. Novel regenerative therapies for ED are controversial but are perceived to offer a durable and safe tissue restorative approach to act as a long-term solution to this cumbersome disease process. Here, we review platelet-rich plasma, amniotic fluid membranes, low-intensity extracorporeal shockwave therapy, and stem cell therapy as regenerative strategies to treat ED. Most of these approaches have preclinical and occasionally clinical data to support their ongoing investigation; however, none of these treatments are currently supported for use in ED patients outside of clinical trials.

Advantages of Phosphodiesterase Type 5 Inhibitors in the Management of Glucose Metabolism Disorders: A Clinical and Translational Issue

Among metabolic diseases, carbohydrate metabolism disorders are the most widespread. The most common glucose pathological conditions are acquired and may increase the risk of type 2 diabetes, obesity, heart diseases, stroke, and kidney insufficiency. Phosphodiesterase type 5 inhibitors (PDE5i) have long been used as an effective therapeutic option for the treatment of erectile dysfunction (ED). Different studies have demonstrated that PDE5i, by sensitizing insulin target tissues to insulin, play an important role in controlling the action of insulin and glucose metabolism, highlighting the protective action of these drugs against metabolic diseases. In this review, we report the latest knowledge about the role of PDE5i in the metabolic diseases of insulin resistance and type 2 diabetes, highlighting clinical aspects and potential treatment approaches. Although various encouraging data are available, further in vivo and in vitro studies are required to elucidate the mechanism of action and their clinical application in humans.

Interventions to Treat Erectile Dysfunction and Premature Ejaculation: An Overview of Systematic Reviews

INTRODUCTION

Sexual dysfunction in men is common, and optimal treatment is complex. Although several systematic reviews concerning treatment approaches exist, a comprehensive overview without limitations concerning the population, interventions, or outcomes is lacking.

AIM

To conduct a "review of reviews" to compare the effectiveness of pharmacologic, non-pharmacologic, and combined interventions.

METHODS

9 electronic databases, relevant journals, and reference lists up to July 2018 were searched. For each intervention, only the most recent and comprehensive meta-analysis or systematic review was included. The methodologic quality of the reviews was appraised using the Assessment of Multiple Systematic Reviews-2 tool.

MAIN OUTCOME MEASURE

Sexual functioning (via intravaginal ejaculatory latency time and international index of erectile function), sexual satisfaction, and adverse effects.

RESULTS

30 systematic reviews were included. For premature ejaculation, several treatments, including oral pharmacotherapy (selective serotonin inhibitors, phosphodiesterase type 5 [PDE5] inhibitors, tricyclic antidepressants, and opioid analgesics), topical anesthetics, and combined drug and behavioral therapies demonstrated significant improvements of 1-5 minutes in the intravaginal ejaculatory latency time. Pharmacologic interventions (PDE5 inhibitors, penile injection, and testosterone), shockwave therapy, lifestyle modifications, and combined therapies (PDE5 inhibitors and psychological intervention) were effective in treating erectile dysfunction. Most pharmacologic therapies were associated with adverse effects.

CONCLUSIONS

There is suggestive evidence that pharmacologic interventions or combined therapies are more effective than non-pharmacologic interventions for treating sexual dysfunction in men; however, a range of treatment options should be presented to individual patients so they may consider the risks and benefits of treatments differently. Evidence related to behavioral and psychological interventions is insufficient compared with that related to drug trials, highlighting the necessity for larger and better randomized controlled trials. Ciocanel O, Power K, Eriksen A. Interventions to Treat Erectile Dysfunction and Premature Ejaculation: An Overview of Systematic Reviews. Sex Med 2019;7:251-269.

Hydroalcoholic Extract of Levisticum officinale Increases cGMP Signaling Pathway by Down-Regulating PDE5 Expression and Induction of Apoptosis in MCF-7 and MDA-MB-468 Breast Cancer Cell Lines

Background:

This study aimed to investigate Levisticum officinale hydroalcoholic extract (LOHE) effect on both cGMP signaling pathway and phosphodiesterase 5 (PDE5) gene expression pattern and to examine the role of LOHE in apoptosis induction of MCF-7 and MDA-MB-468 cell lines.

Methods:

The half maximal inhibitory concentration (IC50) of LOHE was examined in both cell lines using the MTT assay. Using IC50 values of LOHE on both cells, the type of cell death was detected by flowcytometric analysis. The values of PDE5 and cGMP were evaluated by real-time PCR and ELISA methods, respectively.

Results:

The IC50 values were measured as 150 μg/ml for MDA-MB-468 and 200 μg/ml for MCF-7. At 12 hour of treatment, a significant decrease in the PDE5 expression and maximum increase in the amount of intracellular cGMP were observed (p < 0.05). However, these effects were more noticeable in MDA-MB-468 triple-negative cells.

Conclusion:

Our data suggest that LOHE extract could be a potential source for new strategies towards targeting both PDE5 and cGMP signaling pathways.

Undiagnosed prediabetes status is associated with a reduced effectiveness of phosphodiesterase type 5 inhibitors in men with erectile dysfunction

The efficacy of phosphodiesterase type 5 inhibitors (PDE5i) in patients with erectile dysfunction (ED) and undiagnosed prediabetes (PreDM) has been scantly analysed. We aimed to assess rates of and predictors of response to oral treatment in a cohort of ED men naïve for PDE5i with either normo-glycaemia or PreDM or diabetes mellitus (DM). Complete data from 466 men were analysed. Comorbidities were scored with the Charlson Comorbidity Index (CCI). Patients completed the International Index of Erectile Function (IIEF) at baseline and after 3 months of PDE5i treatment. Treatment response was evaluated using the minimal clinically important difference (MCID) (mild: +2; moderate: +5; severe: +7 from baseline IIEF-EF). PreDM status was defined as for the American Diabetes Association (2015) criteria. Descriptive statistics and logistic regression models tested the association between clinical predictors and MCID response. Overall, 253 (56.7%), 105 (23.5%) and 88 (19.7%) patients had normo-glycaemia (=controls), PreDM and DM, respectively. Diabetic and PreDM men were older, had higher BMI, higher CCI scores and lower total testosterone (tT) (all p < 0.01) compared to controls. Median baseline IIEF-EF was lower both in PreDM (14.0 vs. 18.0; p < 0.05) and DM patients (10.0 vs. 18.0; p < 0.001) than in controls. IIEF-EF improved in all groups after treatment (all p < 0.001), but scores were higher in controls compared to both PreDM and DM men at 3-mos assessment (26.0 vs. 20.0 vs. 17.5, respectively; all p < 0.001). Controls more frequently achieved significant MCID than both PreDM and DM patients (65.3 vs. 22.9 vs. 11.8%, respectively; p < 0.01). Age (p < 0.001), baseline IIEF-EF (p < 0.001), and DM status (p = 0.02) were independently associated with MCID. In conclusion, patients with undiagnosed PreDM depicted lower rates of response to PDE5i than normoglycemic men. These findings suggest that even milder forms of glucose impairment are associated with a poorer PDE5i effectiveness in men with ED.

A meta-analysis on efficacy and tolerability of sildenafil for erectile dysfunction in patients with diabetes mellitus

Erectile dysfunction (ED) is a common complication in patients with diabetes mellitus (DM). Sildenafil, a phosphodiesterase-5 inhibitor, is commonly used in patients with ED. This meta-analysis was planned to determine the strength of evidence to assess the efficacy and tolerability of sildenafil in patients with DM-associated ED. Electronic searches were carried out to identify randomized controlled trials (RCTs) which reported clinical efficacy of sildenafil in patients with DM-associated ED. Data were extracted and methodological quality was assessed. Relative Risk (RR) with 95% confidence intervals (CIs) was estimated for the dichotomous outcomes, and the mean difference with 95% CI was estimated for continuous data. Eight randomized controlled trials (RCTs) involving 1172 patients met with our inclusion criteria. In comparison to placebo, sildenafil significantly improved the overall sexual performance in patients of ED associated with DM with relative risk (RR) of answering “yes” to global efficiency question being 3.99 (95% CI: 2.58–6.18) compared to placebo. The rate of discontinuation due to treatment-related adverse reactions was 2.4% in sildenafil arm with RR of 2.67 (95% CI: 0.74–9.62). Sildenafil is an effective and safe medication for the treatment of ED associated with DM.

Down-regulation of lncRNA MEG3 promotes endothelial differentiation of bone marrow derived mesenchymal stem cells in repairing erectile dysfunction

AIMS

In the treatment of diabetes mellitus associated erectile dysfunction (DMED), the intracavernous and periprostatic implantations of bone marrow derived mesenchymal stem cells (BM-MSCs) represent the new therapeutic approaches with great applied prospect. However, the specific mechanisms of BM-MSCs protecting erectile function remain largely unknown.

MATERIALS AND METHODS

The DMED rats were induced and the erectile function was assessed in the models with or without BM-MSCs implantation using intracavernous pressure (ICP)/mean arterial pressure (MAP) ratio. The differentiation of BM-MSCs toward endothelial cells (ECs) was induced by exogenous vascular endothelial growth factor (VEGF) in vitro. RNA pull-down and RIP assays were performed to explore the interaction between MEG3 and FOXM1 protein.

KEY FINDINGS

Intracavernous implantation of BM-MSCs effectively improved the erectile function of DMED rats, which was accompanied by a significant decrease in the expression of MEG3 in the corpus cavernosum tissues. Also, our study revealed that MEG3 expression was significantly down-regulated during the endothelial differentiation of BM-MSCs in vitro. The down-regulation of MEG3 was further confirmed to be conducive to the differentiation of BM-MSCs toward ECs. More importantly, MEG3 promoted the degradation of FOXM1 protein via facilitating FOXM1 ubiquitination, thereby decreasing VEGF expression, which ultimately regulated the endothelial differentiation of BM-MSCs.

SIGNIFICANCE

Taken together, our findings presented the vital role of MEG3 in the repairing processes of BM-MSCs for erectile function and provided new mechanistic insights into the BM-MSCs-mediated DMED repairing.

The phosphodiesterase 5 inhibitor tadalafil regulates lipidic homeostasis in human skeletal muscle cell metabolism

PURPOSE

Tadalafil seems to ameliorate insulin resistance and glucose homeostasis in humans. We have previously reported that tadalafil targets human skeletal muscle cells with an insulin (I)-like effect. We aim to evaluate in human fetal skeletal muscle cells after tadalafil or I: (i) expression profile of I-regulated genes dedicated to cellular energy control, glycolitic activity or microtubule formation/vesicle transport, as GLUT4, PPARγ, HK2, IRS-1, KIF1C, and KIFAP3; (ii) GLUT4, Flotillin-1, and Caveolin-1 localization, all proteins involved in energy-dependent cell trafficking; (iii) activation of I-targeted paths, as IRS-1, PKB/AKT, mTOR, P70/S6K. Free fatty acids intracellular level was measured. Sildenafil or a cGMP synthetic analog were used for comparison; PDE5 and PDE11 gene expression was evaluated in human fetal skeletal muscle cells.

METHODS

RTq-PCR, PCR, western blot, free fatty acid assay commercial kit, and lipid stain non-fluorescent assay were used.

RESULTS

Tadalafil upregulated I-targeted investigated genes with the same temporal pattern as I (GLUT4, PPARγ, and IRS-1 at 3 h; HK2, KIF1C, KIFAP3 at 12 h), re-localized GLUT4 in cell sites positively immune-decorated for Caveolin-1 and Flotillin-1, suggesting the involvement of lipid rafts, induced specific residue phosphorylation of IRS-1/AKT/mTOR complex in association with free fatty acid de novo synthesis. Sildenafil or GMP analog did not affect GLUT4 trafficking or free fatty acid levels.

CONCLUSION

In human fetal skeletal muscle cells tadalafil likely favors energy storage by modulating lipid homeostasis via IRS-1-mediated mechanisms, involving activation of I-targeted genes and intracellular cascade related to metabolic control. Those data provide some biomolecular evidences explaining, in part, tadalafil-induced favorable control of human metabolism shown by clinical studies.

Current and future therapies for addressing the effects of inflammation on HDL cholesterol metabolism

Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. Inflammatory processes arising from metabolic abnormalities are known to precipitate the development of CVD. Several metabolic and inflammatory markers have been proposed for predicting the progression of CVD, including high density lipoprotein cholesterol (HDL-C). For ~50 years, HDL-C has been considered as the atheroprotective 'good' cholesterol because of its strong inverse association with the progression of CVD. Thus, interventions to increase the concentration of HDL-C have been successfully tested in animals; however, clinical trials were unable to confirm the cardiovascular benefits of pharmaceutical interventions aimed at increasing HDL-C levels. Based on these data, the significance of HDL-C in the prevention of CVD has been called into question. Fundamental in vitro and animal studies suggest that HDL-C functionality, rather than HDL-C concentration, is important for the CVD-preventive qualities of HDL-C. Our current review of the literature positively demonstrates the negative impact of systemic and tissue (i.e. adipose tissue) inflammation in the healthy metabolism and function of HDL-C. Our survey indicates that HDL-C may be a good marker of adipose tissue health, independently of its atheroprotective associations. We summarize the current findings on the use of anti-inflammatory drugs to either prevent HDL-C clearance or improve the function and production of HDL-C particles. It is evident that the therapeutic agents currently available may not provide the optimal strategy for altering HDL-C metabolism and function, and thus, further research is required to supplement this mechanistic approach for preventing the progression of CVD.

LINKED ARTICLES

This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

Sex and gender differences in therapy of type 2 diabetes

Clinical guidelines for the management of type 2 diabetes recommend individual therapy considering age, duration of disease, presence of complication and risk of hypoglycaemia. However, at present, the patient's sex has no impact on clinical decisions. Yet, there is mounting data pointing at biological and psychosocial differences between men and women with great impact on progression of disease and complications. Moreover, choices and preferences of therapeutic strategies as well as adherence to lifestyle and pharmacological interventions differ in both sexes. In addition, drug therapy may have sex-specific side effects. Therefore, there is need of more research on biological differences and of evidence-based individualised targeted sex-sensitive therapeutic concepts. Clinical guidelines must consider relevant sex-differences. Development and implementation of sex-specific programs may help to improve adherence to therapy and to reduce progression of disease and development of complications. A more gender-sensitive clinical approach may improve quality of life and increase health and life expectancy in men and women with type 2 diabetes.

First-generation phosphodiesterase type 5 inhibitors dropout: a comprehensive review and meta-analysis

The discontinuation rate with phosphodiesterase type 5 inhibitors (PDE5i) remains very high. The aim of this study was to review and meta-analyze currently available data regarding dropout of the first-generation of PDE5i including sildenafil, vardenafil, and tadalafil. An extensive Medline Embase and Cochrane search was performed including the following words: 'PDE5i', 'discontinuation'. All observational studies reporting the dropout rate of PDE5i and its specific causes without any arbitrary restrictions were included. Out of 103 retrieved articles, 22 were included in the study. Retrieved trials included a total of 162,936 patients with a mean age of 58.8 ± 7.9 years. Prevalence of reported comorbid diabetes and hypertension were 27.7% and 36.9%, respectively. PDE5i were associated with a mean discontinuation rate of 4% per month (almost 50% after one year). This rate was higher in younger subjects and in those reporting a higher prevalence of associated morbidities. Six main reasons of PDE5i dropout were identified in the evaluated trials. Partner-related problems and lack of efficacy represented the most important reasons for PDE5i discontinuation, although no significant difference among factors was detected. In conclusion, despite their high efficacy and easy administration, the discontinuation rate and dissatisfaction with PDE5i are still very high. Our data showed that no single factor plays a major role in PDE5i dropout, suggesting that the discontinuation rate is usually because of a combination of both medical problems and psychosocial and relational factors.

Coadjuvants in the Diabetic Complications: Nutraceuticals and Drugs with Pleiotropic Effects

Because diabetes mellitus (DM) is a multifactorial metabolic disease, its prevention and treatment has been a constant challenge for basic and clinical investigators focused on translating their discoveries into clinical treatment of this complex disorder. In this review, we highlight recent experimental and clinical evidences of potential coadjuvants in the management of DM, such as polyphenols (quercetin, resveratrol and silymarin), cultured probiotic microorganisms and drugs acting through direct/indirect or pleiotropic effects on glycemic control in DM. Among several options, we highlight new promising therapeutic coadjuvants, including chemical scavengers, the probiotic kefir and the phosphodiesterase 5 inhibitors, which besides the reduction of hyperglycemia and ameliorate insulin resistance, they reduce oxidative stress and improve endothelial dysfunction in the systemic vascular circulation. In the near future, experimental studies are expected to clear the intracellular pathways involving coadjuvants. The design of clinical trials may also contribute to new strategies with coadjuvants against the harmful effects of diabetic complications.

Antioxidant Potential and Ability of Phloroglucinol to Decrease Formation of Advanced Glycation End Products Increase Efficacy of Sildenafil in Diabetes-Induced Sexual Dysfunction of Rats

INTRODUCTION

Diabetes-induced sexual dysfunction is associated with an increase in oxidative stress. Scavengers of reactive oxygen species (ROS) have been shown to reduce oxidative stress and aid in the management of sexual dysfunction in diabetes.

AIM

The aim of the study was to test the hypothesis that antioxidant, which scavenge ROS and reduce formation of advanced glycation end products (AGEs), can potentiate efficacy of phosphodiesterase type 5 inhibitors in diabetes-induced sexual dysfunction that is associated with oxidative stress.

MATERIALS AND METHODS

Effect of phloroglucinol and sildenafil on serum glucose level, sexual function, penile smooth muscle : collagen ratio, and phenylephrine precontracted corpus cavernosum smooth muscle (CCSM) was studied. The ability of phloroglucinol to reduce the formation of AGEs and its ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) was also evaluated.

MAIN OUTCOME MEASURES

Antioxidant potential of phloroglucinol was studied in addition to its effect on diabetes-induced sexual dysfunction in presence and absence of sildenafil.

RESULTS

Phloroglucinol (50 mg/kg, p.o.) significantly decreased serum glucose level and increased sexual function in streptozotocin-induced diabetic rats when compared with diabetic control rats. Sildenafil (5 mg/kg, p.o.) had no effect on glycemia but significantly increased sexual function of diabetic rats. Coadministration of phloroglucinol increased the efficacy of sildenafil by improving sexual function. Treatment of diabetic rats with phloroglucinol + sildenafil maintained smooth muscle : collagen levels similar to that of normal rat penile tissue. Phloroglucinol decreased formation of AGEs and significantly scavenged DPPH radical activity in vitro. Sildenafil relaxed isolated CCSM of normal rat and diabetic rat significantly, but phloroglucinol did not show any significant effect. Phloroglucinol also inhibited human CYP3A4 enzyme activity in vitro.

CONCLUSION

Phloroglucinol coadministration increases efficacy of sildenafil in diabetes-induced sexual dysfunction. However, further studies are required to ascertain the benefits of phloroglucinol owing to its undesirable CYP3A4 inhibition activity.