Sildenafil, a novel effective oral therapy for male erectile dysfunction

β-aminopropionitrile-induced thoracic aortopathy is refractory to cilostazol and sildenafil in mice

Thoracic aortopathies are life-threatening diseases including aneurysm, dissection, and rupture. Phosphodiesterases (PDEs) regulate intracellular cyclic nucleotide concentrations. Recent studies report the influences of cilostazol, a PDE3 inhibitor, and sildenafil, a PDE5 inhibitor, on abdominal aortic aneurysm formation. However, their impacts on thoracic aortopathy remain unknown. In this study, we investigated whether cilostazol and sildenafil affect thoracic aortopathy induced by β-aminopropionitrile (BAPN) administration in mice. Bulk RNA sequencing analysis revealed that BAPN administration upregulated Pde3a transcription in the ascending aorta and Pde5a in both ascending and descending regions before thoracic aortopathy formation. Next, we tested the effects of cilostazol or sildenafil on BAPN-induced thoracic aortopathy. BAPN-administered mice were fed a diet supplemented with either cilostazol or sildenafil. Mass spectrometry measurements determined the presence of cilostazol or sildenafil in the plasma of mice fed drug-supplemented diets. However, neither drug altered BAPN-induced aortic rupture nor aneurysm formation and progression. These results provide evidence that cilostazol and sildenafil did not influence BAPN-induced thoracic aortopathy in mice.

Computational drug repurposing: approaches, evaluation of in silico resources and case studies

Repurposing of existing drugs for new indications has attracted substantial attention owing to its potential to accelerate drug development and reduce costs. Hundreds of computational resources such as databases and predictive platforms have been developed that can be applied for drug repurposing, making it challenging to select the right resource for a specific drug repurposing project. With the aim of helping to address this challenge, here we overview computational approaches to drug repurposing based on a comprehensive survey of available in silico resources using a purpose-built drug repurposing ontology that classifies the resources into hierarchical categories and provides application-specific information. We also present an expert evaluation of selected resources and three drug repurposing case studies implemented within the Horizon Europe REMEDi4ALL project to demonstrate the practical use of the resources. This comprehensive Review with expert evaluations and case studies provides guidelines and recommendations on the best use of various in silico resources for drug repurposing and establishes a basis for a sustainable and extendable drug repurposing web catalogue.

An overview on pharmaceutical applications of phosphodiesterase enzyme 5 (PDE5) inhibitors

Phosphodiesterase enzyme 5 (PDE5) inhibitors have emerged as one of the leading molecules for the treatment of erectile dysfunction (ED). PDE5 inhibitors are categorized structurally into several classes. PDE5 inhibitors have been a multidisciplinary endeavor that attracts the attention of researchers because of their multiple pharmaceutical applications. Beyond their action on ED, PDE5 inhibitors are widely used in treatment of benign prostatic hypertrophy (BPH), Eisenmenger's syndrome, Raynaud's Disease, Intrauterine growth retardation (IUGR), Mountain sickness, Bladder pain syndrome/interstitial cystitis (BPS/IC), pulmonary arterial hypertension and type II diabetes (insulin resistance). In addition, PDE5 inhibitors also show promising antiproliferative activity, anti-Alzheimer and COX-1/COX-2 inhibitory activity (anti-inflammatory). Pharmacokinetics, Pharmacogenetics and toxicity of PDE5 inhibitors were finally explored. The diverse therapeutic applications, the high feasibility of structural modification and the appropriate pharmacokinetic properties of PDE5 inhibitors have motivated researchers to develop new scaffolds that have been either under clinical trials or approved by FDA and utilize them to overcome some recent global concerns, such as COVID-19.

Phosphodiesterase 5A regulates the vomeronasal pump in mice

The vomeronasal organ (VNO) is a specialized chemoreceptive structure in many vertebrates that detects chemical stimuli, mostly pheromones, which often elicit innate behaviors such as mating and aggression. Previous studies in rodents have demonstrated that chemical stimuli are actively transported to the VNO via a blood vessel-based pumping mechanism, and this pumping mechanism is necessary for vomeronasal stimulation in behaving animals. However, the molecular mechanisms that regulate the vomeronasal pump remain mostly unknown. In this study, we observed a high level of expression of phosphodiesterase 5A (PDE5A) in the vomeronasal blood vessel of mice. We provided evidence to support the potential role of PDE5A in vomeronasal pump regulation. Local application of PDE5A inhibitors-sildenafil or tadalafil-to the vomeronasal organ (VNO) reduced stimulus delivery into the VNO, decreased the pheromone-induced activity of vomeronasal sensory neurons, and attenuated male-male aggressive behaviors. PDE5A is well known to play a role in regulating blood vessel tone in several organs. Our study advances our understanding of the molecular regulation of the vomeronasal pump.

Comprehensive review of potential drugs with anti-pulmonary fibrosis properties

Pulmonary fibrosis is a chronic and progressive lung disease characterized by the accumulation of scar tissue in the lungs, which leads to impaired lung function and reduced quality of life. The prognosis for idiopathic pulmonary fibrosis (IPF), which is the most common form of pulmonary fibrosis, is generally poor. The median survival for patients with IPF is estimated to be around 3-5 years from the time of diagnosis. Currently, there are two approved drugs (Pirfenidone and Nintedanib) for the treatment of IPF. However, Pirfenidone and Nintedanib are not able to reverse or cure pulmonary fibrosis. There is a need for new pharmacological interventions that can slow or halt disease progression and cure pulmonary fibrosis. This review aims to provide an updated overview of current and future drug interventions for idiopathic pulmonary fibrosis, and to summarize possible targets of potential anti-pulmonary fibrosis drugs, providing theoretical support for further clinical combination therapy or the development of new drugs.

Phosphodiesterase in heart and vessels: from physiology to diseases

Phosphodiesterases (PDEs) are a superfamily of enzymes that hydrolyze cyclic nucleotides, including cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Both cyclic nucleotides are critical secondary messengers in the neurohormonal regulation in the cardiovascular system. PDEs precisely control spatiotemporal subcellular distribution of cyclic nucleotides in a cell- and tissue-specific manner, playing critical roles in physiological responses to hormone stimulation in the heart and vessels. Dysregulation of PDEs has been linked to the development of several cardiovascular diseases, such as hypertension, aneurysm, atherosclerosis, arrhythmia, and heart failure. Targeting these enzymes has been proven effective in treating cardiovascular diseases and is an attractive and promising strategy for the development of new drugs. In this review, we discuss the current understanding of the complex regulation of PDE isoforms in cardiovascular function, highlighting the divergent and even opposing roles of PDE isoforms in different pathogenesis.

Highly sensitive plasmonic paper substrate fabricated via amphiphilic polymer self-assembly in microdroplet for detection of emerging pharmaceutical pollutants

We report an innovative and facile approach to fabricating an ultrasensitive plasmonic paper substrate for surface-enhanced Raman spectroscopy (SERS). The approach exploits the self-assembling capability of poly(styrene-b-2-vinyl pyridine) block copolymers to form a thin film at the air-liquid interface within the single microdroplet scale for the first time and the subsequent in situ growth of silver nanoparticles (AgNPs). The concentration of the block copolymer was found to play an essential role in stabilizing the droplets during the mass transfer phase and formation of silver nanoparticles, thus influencing the SERS signals. SEM analysis of the morphology of the plasmonic paper substrates revealed the formation of spherical AgNPs evenly distributed across the surface of the formed copolymer film with a size distribution of 47.5 nm. The resultant enhancement factor was calculated to be 1.2 × 107, and the detection limit of rhodamine 6G was as low as 48.9 pM. The nanohybridized plasmonic paper was successfully applied to detect two emerging pollutants-sildenafil and flibanserin-with LODs as low as 1.48 nM and 3.45 nM, respectively. Thus, this study offers new prospects for designing an affordable and readily available, yet highly sensitive, paper-based SERS substrate with the potential for development as a lab-on-a-chip device.

Phosphodiesterase-5 (PDE-5) Inhibitors as Therapy for Cerebrovascular Dysfunction in Chronic Traumatic Brain Injury

Multiple phase III randomized controlled trials (RCTs) for pharmacologic interventions in traumatic brain injury (TBI) have failed despite promising results in experimental models. The heterogeneity of TBI, in terms of pathomechanisms and impacted brain structures, likely contributes to these failures. Biomarkers have been recommended to identify patients with relevant pathology (predictive biomarkers) and confirm target engagement and monitor therapy response (pharmacodynamic biomarkers). Our group focuses on traumatic cerebrovascular injury as an understudied endophenotype of TBI and is validating a predictive and pharmacodynamic imaging biomarker (cerebrovascular reactivity; CVR) in moderate-severe TBI. We aim to extend these studies to milder forms of TBI to determine the optimal dose of sildenafil for maximal improvement in CVR. We will conduct a phase II dose-finding study involving 160 chronic TBI patients (mostly mild) using three doses of sildenafil, a phosphodiesterase-5 (PDE-5) inhibitor. The study measures baseline CVR and evaluates the effect of escalating sildenafil doses on CVR improvement. A 4-week trial of thrice daily sildenafil will assess safety, tolerability, and clinical efficacy. This dual-site 4-year study, funded by the Department of Defense and registered in ClinicalTrials.gov (NCT05782244), plans to launch in June 2023. Biomarker-informed RCTs are essential for developing effective TBI interventions, relying on an understanding of underlying pathomechanisms. Traumatic microvascular injury (TMVI) is an attractive mechanism which can be targeted by vaso-active drugs such as PDE-5 inhibitors. CVR is a potential predictive and pharmacodynamic biomarker for targeted interventions aimed at TMVI. (Trial registration: NCT05782244, ClinicalTrials.gov ).

Ameliorative effect of hesperidin against high dose sildenafil-induced liver and testicular oxidative stress and altered gene expression in male rats

BACKGROUND

The clinical use of sildenafil citrate (Viagra), a drug used to treat erectile dysfunction, is limited because of its many side effects on tissues. In this context, we aimed to investigate the protective effects of hesperidin, a citrus flavonoid, on hepatic and testicular damage induced by a high dose of sildenafil citrate in male rats. Rats were randomly divided into four groups. The first group was used as the control group. The second group was orally administered sildenafil citrate at a high dose of 75 mg/kg thrice a week. In the third group, hesperidin was administered orally at a dose of 50 mg/kg/day. The fourth group was administered 75 mg/kg sildenafil citrate three times a week with 50 mg/kg hesperidin daily. The experiment lasted for 28 days.

RESULTS

In the sildenafil-treated groups, blood indices were altered, liver function tests were deranged, and serum testosterone levels were reduced. In the liver and testicular tissue, sildenafil citrate treatment resulted in significant reductions in catalase and total antioxidant capacity; as well as increased malondialdehyde, reactive oxygen species, and nitrous oxide levels. In addition, sildenafil citrate treatment caused abnormal histopathological patterns in both the liver and the testes. Liver vascular endothelial growth factor and testicular steroidogenic acute regulatory protein gene expression were upregulated.

CONCLUSIONS

Hesperidin attenuated the harmful effects of intensive sildenafil citrate treatment on liver and testicular functions, alleviated oxidative stress and normalized blood indices. Therefore, hesperidin could be protective against sildenafil citrate-induced oxidative damage that may develop over the long term.

Function of sildenafil on diseases other than urogenital system: An umbrella review

Background: To investigate the function of sildenafil on diseases other than urogenital system, an umbrella review was conducted. Methods: Meta-analysis and systematic reviews on this topic were comprehensively evaluated in this umbrella review. Quality of evidence was evaluated through AMSTAR and the Grading of Recommendations, Assessment, Development and Evaluation system to generate a reliable and valid conclusion. Results: 77 out of 1164 meta-analysis were enrolled. 33 significant outcomes and 41 non-significant outcomes were extracted from all eligible articles. We found sildenafil did significant help in reducing arterial systolic pressure, mean pulmonary arterial pressure, pulmonary arterial pressure, systolic pulmonary arterial pressure in patients with pulmonary and cardiovascular diseases. Besides, sildenafil also improved exercise capacity or performance in patients with pulmonary and cardiovascular diseases. Other than these patients, this drug contributed great help in pregnant women with fetal growth restriction and preeclampsia by increasing the weight of newborns and lowering uterine and umbilical pulsatility indices. Additionally, it was reported that utilization of sildenafil has brought increased risk of melanoma. Conclusion: We can conclude from our study that sildenafil played an important role in many fields, especially in vascular protection. This finding provides a strong evidence for further expansion of sildenafil utilization in other diseases.

Effect of phosphodiesterase-4 inhibitor rolipram on colonic hypermotility in water avoidance stress rat model

BACKGROUND

Phosphodiesterase (PDE) inhibition has been reported to play a role in regulating gut motility, but the evidence is insufficient, and the mechanism remains unknown. The aim of this study was to investigate the possible role of phosphodiesterase-4 (PDE4) inhibitor rolipram in water avoidance stress-induced colonic hypermotility.

METHODS

A rat model of irritable bowel syndrome (IBS) with diarrhea (IBS-D) was established by water avoidance stress (WAS). Intestinal motility was assessed by fecal pellets expulsion per hour. The cyclic adenosine monophosphate (cAMP) and nitric oxide (NO) level in colon tissue were detected using ELISA assay and the Griess test, respectively. Western blotting was performed to assess the protein level of PDE, PKA/p-CREB, and neuronal nitric oxide synthase (nNOS) in the colon. To determine the role of rolipram in gut motility, the rats of the WAS + Rolipram and Rolipram group were injected with rolipram intraperitoneally. The colonic contractile activity was recorded with a RM6240 multichannel physiological signal system.

KEY RESULTS

WAS-induced gastrointestinal hypermotility and increased defecation in rats. After repeated stress, protein levels of PDE4 in the colon were promoted while PKA/p-CREB and nNOS were highly decreased. cAMP content in colon tissue did not change significantly. However, NO content decreased after WAS, and rolipram partly enhanced NO in WAS-exposed rats. In addition, intraperitoneal injection of rolipram partly inhibited the colonic motility in vivo. Meanwhile, we observed rolipram inhibited the contraction of colonic smooth muscle strips, and this inhibitory effect was abolished by Nω-Nitro-L-arginine (L-NNA), a nitric oxide synthase (NOS) inhibitor, tetrodotoxin (TTX), a blocker of neuronal voltage-dependent Na⁺ channels, Rp-Adenosine 3',5'-cyclic monophosphorothioate triethylammonium salt hydrate (Rp-cAMPS), an antagonist of cAMP.

CONCLUSIONS AND INFERENCES

Rolipram could relieve stress-induced gastrointestinal hypermotility. This effect may be partly through the cAMP-PKA-p-CREB pathway and NO pathway.

Long-term high-dose L-arginine supplementation in patients with vasculogenic erectile dysfunction: a multicentre, double-blind, randomized, placebo-controlled clinical trial

PURPOSE

The current randomized, double-blind, placebo-controlled clinical trial addressed the effects on penile erectile function of relatively high daily oral doses (6 g/day) of L-ARG for 3 months (N = 51) compared to placebo (N = 47), in patients with vasculogenic ED, with comparison between mild-moderate and severe vasculogenic ED.

METHODS

The outcome measures included IIEF-6 score and cavernous arteries peak systolic flow velocity (PSV) at dynamic penile duplex ultrasonography (PDU).

RESULTS

L-ARG supplementation for 3 months significantly increased IIEF-6 score in the overall cohort (p < 0.0001) and in subgroups of patients with mild-moderate (p < 0.0001) and severe (p = 0.007) vasculogenic ED; PSV was significantly increased in the overall cohort (p < 0.0001) and in patients with mild-moderate (p < 0.0001), but not severe vasculogenic ED. At study completion, 74% of patients improved ED degree category, although only 24% of patients, mainly belonging to the baseline category of mild ED, reached IIEF-6 scores compatible with absence of ED; moreover, 20% of patients, exclusively belonging to the baseline category of mild-moderate vasculogenic ED, reached PSV values compatible with absence of ED.

CONCLUSION

The results of the current study demonstrated that supplementation with relatively high doses of L-ARG as a single compound for 3 months significantly improved penile erectile function, assessed by both IIEF-6 score and PSV at dynamic PDU in patients with mild-moderate, and improved IIEF-6 score, but not PSV, in patients with severe vasculogenic ED, therefore suggesting that L-ARG might be an alternative treatment in mild-moderate vasculogenic ED patients experiencing adverse effects or with contraindications for chronic treatment with PDE5i compounds.

Cyclic nucleotide phosphodiesterase inhibition as a potential therapeutic target in renal ischemia reperfusion injury

AIMS

Ischemia/reperfusion (I/R) occurs in renal artery stenosis, partial nephrectomy and most commonly during kidney transplantation. It brings serious consequences such as DGF (Delayed Graft Function) or organ dysfunction leading to renal failure and ultimate death. There is no effective therapy to handle the consequences of Renal Ischemia/Reperfusion (I/R) injury. Cyclic nucleotides, cAMP and cGMP are the important second messengers that stimulate intracellular signal transduction for cell survival in response to growth factors and peptide hormones in normal tissues and in kidneys plays significant role that involves vascular tone regulation, inflammation and proliferation of parenchymal cells. Renal ischemia and subsequent reperfusion injury stimulate signal transduction pathways involved in oxidative stress, inflammation, alteration in renal blood flow leading to necrosis and apoptosis of renal cell.

MATERIALS AND METHODS

An extensive literature review of various search engines like PubMed, Medline, Bentham, Scopus, and EMBASE (Elsevier) databases was carried out. To understand the functioning of Phosphodiesterases (PDEs) and its pharmacological modulation in Renal Ischemia-Reperfusion Injury.

KEY FINDINGS

Current therapeutic options may not be enough to treat renal I/R injury in group of patients and therefore, the current review has discussed the general characteristics and physiology of PDEs and preclinical-studies defining the relationship between PDEs expression in renal injury due to I/R and its outcome on renal function.

SIGNIFICANCE

The role of PDE inhibitors in renal I/R injury and the clinical status of drugs for various renal diseases have been summarized in this review.

Sildenafil in ophthalmology: An update

Sildenafil citrate, a selective oral phosphodiesterase 5 inhibitor, is a widely used drug for erectile dysfunction that acts by elevating cGMP levels and causing smooth muscle relaxation. It also has 10% activity against PDE6, a key enzyme in phototransduction cascade in the retina. Recent ocular imaging developments have further revealed the influence of sildenafil on ocular hemodynamics, particularly choroidal perfusion. Choroidal thickness is increased, and choroidal perfusion is also enhanced by autoregulatory mechanisms that are further dependent on age and microvascular abnormalities. Studies demonstrating high intraocular pressure via a "parallel pathway" from increased choroidal volume and blood flow to the ciliary body have challenged previous concepts. Another new observation is the effect of sildenafil on bipolar cells and cyclic-nucleotide gated channels. We discuss potential deleterious effects (central serous chorioretinopathy, glaucoma, ischemic optic neuropathy, and risks to recessive carriers of retinitis pigmentosa), potential beneficial effects (ameliorate choroidal ischemia, prevent thickening of Bruch membrane, and promote recovery of the ellipsoid zone) in macular degeneration, as well as potential drug interactions of sildenafil.

Contribution of sewage to occurrence of phosphodiesterase-5 inhibitors in natural water

Phosphodiesterase-5 inhibitors (PDE-5i, such as Sildenafil, Tadalafil and Vardenafil, mainly prescribed to treat erectile dysfunction) and their generic drug equivalents have been widely marketed and consumed in Korea. From the concentrations detected in wastewater, we could deduce that relatively large amounts of PDE-5i were consumed without a legal prescription. Thus, PDE-5i’s presence in the environment via sewage is unavoidable, and their environmental fate within a sewage treatment plant (STP) should be evaluated. In this study, we investigated the occurrence of three PDE-5i analogs in the influent and effluent of two STPs and the receiving water bodies. The PDE-5i concentration in total reached 62 ± 12 (STP#1) and 88 ± 37 ng L⁻¹ (STP#2) in the sewage influent; about 70% of it was Sildenafil in both STPs. However, they were hardly removed by the STPs as the removal efficiency of the STPs was less than 10% ± 5%. Therefore, the pharmaceuticals were detected in the receiving water (lower than 7 ng L⁻¹as a total amount) and the concentration slightly increased downstream of the STPs. A simple mass balance model applied for the compounds in the STP effluent and receiving water bodies also confirmed that the discharged PDE-5i were quite persistent. Lastly, we identified temporal and regional patterns in the consumption of the drugs from daily variations of PDE-5i in the influent to these two STPs. For instance, the levels of PDE-5i in the sewage significantly increased on weekends (from Friday to Saturday), and especially in the area where adult-entertainment businesses are common. We estimated that the amount of PDE-5i consumption in this area was 31% higher than that in the area with fewer nightlife spots. Considering that they are pharmaceutically active and resistant to treatment processes within an STP, it is advised that a regular monitoring and management program for PDE-5i should be developed to prevent the discharge of the pharmaceuticals into the water environment.

Exploration of databases and methods supporting drug repurposing: a comprehensive survey

Drug development involves a deep understanding of the mechanisms of action and possible side effects of each drug, and sometimes results in the identification of new and unexpected uses for drugs, termed as drug repurposing. Both in case of serendipitous observations and systematic mechanistic explorations, confirmation of new indications for a drug requires hypothesis building around relevant drug-related data, such as molecular targets involved, and patient and cellular responses. These datasets are available in public repositories, but apart from sifting through the sheer amount of data imposing computational bottleneck, a major challenge is the difficulty in selecting which databases to use from an increasingly large number of available databases. The database selection is made harder by the lack of an overview of the types of data offered in each database. In order to alleviate these problems and to guide the end user through the drug repurposing efforts, we provide here a survey of 102 of the most promising and drug-relevant databases reported to date. We summarize the target coverage and types of data available in each database and provide several examples of how multi-database exploration can facilitate drug repurposing.

Predicting therapeutic drugs for hepatocellular carcinoma based on tissue-specific pathways

Hepatocellular carcinoma (HCC) is a significant health problem worldwide with poor prognosis. Drug repositioning represents a profitable strategy to accelerate drug discovery in the treatment of HCC. In this study, we developed a new approach for predicting therapeutic drugs for HCC based on tissue-specific pathways and identified three newly predicted drugs that are likely to be therapeutic drugs for the treatment of HCC. We validated these predicted drugs by analyzing their overlapping drug indications reported in PubMed literature. By using the cancer cell line data in the database, we constructed a Connectivity Map (CMap) profile similarity analysis and KEGG enrichment analysis on their related genes. By experimental validation, we found securinine and ajmaline significantly inhibited cell viability of HCC cells and induced apoptosis. Among them, securinine has lower toxicity to normal liver cell line, which is worthy of further research. Our results suggested that the proposed approach was effective and accurate for discovering novel therapeutic options for HCC. This method also could be used to indicate unmarked drug-disease associations in the Comparative Toxicogenomics Database. Meanwhile, our method could also be applied to predict the potential drugs for other types of tumors by changing the database.

S-Persulfidation: Chemistry, Chemical Biology, and Significance in Health and Disease

Significance: S-Persulfidation generates persulfide adducts (RSSH) on both small molecules and proteins. This process is believed to be critical in the regulation of biological functions of reactive sulfur species such as H₂S, as well as in signal transduction. S-Persulfidation also plays regulatory roles in human health and diseases. Recent Advances: Some mechanisms underlying the generation of low-molecular-weight persulfides and protein S-persulfidation in living organisms have been uncovered. Some methods for the specific delivery of persulfides and the detection of persulfides in biological systems have been developed. These advances help to pave the road to better understand the functions of S-persulfidation. Critical Issues: Persulfides are highly reactive and unstable. Currently, their identification relies on trapping them by S-alkylation, but this is not always reliable due to rapid sulfur exchange reactions. Therefore, the presence, identity, and fates of persulfides in biological environments are sometimes difficult to track. Future Directions: Further understanding the fundamental chemistry/biochemistry of persulfides and development of more reliable detection methods are needed. S-Persulfidation in specific protein targets is essential in organismal physiological health and human disease states. Besides cardiovascular and neuronal systems, the roles of persulfidation in other systems need to be further explored. Contradictory results of persulfidation in biology, especially in cancer, need to be clarified.

DLS: A Link Prediction Method Based on Network Local Structure for Predicting Drug-Protein Interactions

The studies on drug-protein interactions (DPIs) had significant for drug repositioning, drug discovery, and clinical medicine. The biochemical experimentation (in vitro) requires a long time and high cost to be confirmed because it is difficult to estimate. Therefore, a feasible solution is to predict DPIs efficiently with computers. We propose a link prediction method based on drug-protein interaction (DPI) local structural similarity (DLS) for predicting the DPIs. The DLS method combines link prediction and binary network structure to predict DPIs. The ten-fold cross-validation method was applied in the experiment. After comparing the predictive capability of DLS with the improved similarity-based network prediction method, the results of DLS on the test set are significantly better. Moreover, several candidate proteins were predicted for three approved drugs, namely captopril, desferrioxamine and losartan, and these predictions are further validated by the literature. In addition, the combination of the Common Neighborhood (CN) method and the DLS method provides a new idea for the integrated application of the link prediction method.

Effect of a Condom Cover on Vaginal Photoplethysmographic Responses

INTRODUCTION

The vaginal photoplethysmograph (VPP) is a reusable intravaginal device often employed in sexual psychophysiology studies to assess changes in vaginal blood flow, an indicator of sexual arousal.

AIM

To test whether placing a disposable cover on the VPP probe impacts the acquired data. A condom cover would reduce risk of disease transmission and likely increase participant comfort but may negatively impact the VPP signal.

METHOD

The genital responses of 25 cisgender women (mean age = 21.3 years, standard deviation = 2.6) were assessed with VPP in a within-subjects design with 2 conditions-with and without a polyisoprene condom cover. Sexual responses were elicited by audiovisual film clips that varied in erotic intensity: nonsexual (nonsexual male-female interaction), low-intensity sexual (nude exercise), and high-intensity sexual (male-female intercourse). Women continuously rated their sexual arousal during stimulus presentations.

MAIN OUTCOME MEASURE

Change in vaginal pulse amplitude and also self-reported sexual arousal.

RESULTS

The magnitude of sexual response to each stimulus category and the overall pattern of results were found to be highly similar in the cover-off and cover-on conditions. The high-intensity sexual stimulus category elicited a greater sexual response than all other categories. The low-intensity sexual category elicited a (small) genital response in only the cover-on condition, although we suspect this is a spurious finding. There was no difference in the average number of edited movement artifacts across conditions.

CLINICAL IMPLICATIONS

Potential benefits of encasing the VPP probe with a protective cover include enhanced participant safety and comfort, especially if assessing genital responses of high-risk or immunocompromised samples. The use of a cover complies with current guidelines for reprocessing semi-critical medical devices (eg, vaginal ultrasound probes) in many regions.

STRENGTHS & LIMITATIONS

Although the idea of a VPP probe cover had been discussed among sexual psychophysiology researchers, this is the first study to empirically test whether a cover could jeopardize VPP data. Potential limitations include the use of a 10-Hz VPP sampling rate and a cover that was not tailored to the size of the VPP probe.

CONCLUSION

Placing a protective cover on the VPP probe did not appear to meaningfully impact sexual arousal or the VPP data. Based on these results and the potential advantages of a protective cover, researchers may wish to integrate the use a condom cover in their experiment protocols and clinical applications. Sawatsky ML, Lalumière ML. Effect of a Condom Cover on Vaginal Photoplethysmographic Responses. J Sex Med 2020; 17:702-715.

The Effect of Vaginal Sildenafil on The Outcome of Assisted Reproductive Technology Cycles in Patients with Repeated Implantation Failures: A Randomized Placebo-Controlled Trial

Background

The aim of this study was to investigate the effects of vaginal sildenafil on the outcome of patients with at least two unsuccessful in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) attempts.

Materials and Methods

In this randomized placebo-controlled trial study, a total of 66 infertile women aged ≤38 years, with a history of normal ovarian reserve, two prior consecutive failed IVF/ICSI attempts, human chorionic gonadotropin (hCG) day endometrial thickness <7 mm in all prior IVF/ICSI cycles, normal endometrial appear- ance by either hysteroscopy, hysterosonography, or hysterosalpingography enrolled in this study. The conventional gonadotropin-releasing hormone (GnRH) protocol was used for ovarian stimulation. The patients were randomly divided into three groups: vaginal sildenafil (suppository-100 mg/daily), vaginal placebo/sildenafil (suppository-100 mg/daily), and vaginal placebo (suppository). Each patient underwent colour Doppler ultrasound on day 14 of their previous cycle to investigate any abnormalities in the uterus and adnexa. Endometrial thickness, echo pattern, uterine artery resistance, and pulsatility indices were recorded pre- and post-treatment. The primary outcome measures were implantation, chemical and clinical pregnancy rates. For data analysis, SPSS version 20 software was used. In all tests, the significance level was considered less than 0.05.

Results

There was no significant difference between three groups in endometrial thickness on the hCG injection day. The chemical pregnancy in women who received sildenafil (alone or in combination with placebo) showed a two-fold increase in comparison to the placebo group. This increase was clinically meaningful, but according to sample size, it was statistically non-significant. The results of our study showed that the implantation was higher in women who received placebo/sildenafil compared to the other groups. The abortion rate was not statistically significant among the groups.

Conclusion

Vaginal sildenafil may conceivably improve chemical pregnancy rates in repeated IVF failure patients. Further randomized clinical trials using oral or vaginal sildenafil with higher sample size are recommended (Registra- tion number: NCT03192709).

In Silico Mapping of Essential Residues in the Catalytic Domain of PDE5 Responsible for Stabilization of Its Commercial Inhibitors

Phosphodiesterase type 5 (PDE5) is an important enzyme associated with the hydrolysis of cyclic guanosine monophosphate (cGMP) to guanosine monophosphate (GMP). Due to the relevant role of second messenger cGMP as a mediator in many physiological processes, efforts have been converged to find a safe pharmacological approach, seeking a specific, selective and potent inhibitor of the PDE5 enzyme. There are five commercial drugs with potential for clinical use: tadalafil, sildenafil, avanafil, udenafil and vardenafil. Here, we applied molecular modeling to obtain different profiles of protein–ligand interactions by adopting distinct PDE5 structures, specifically PDBid:1XOZ and two extracted from molecular dynamics (MD) simulations. The results generated by molecular docking showed several possibilities for inhibitor interactions with the catalytic pocket. Tadalafil, sildenafil and vardenafil were clearly stabilized by Gln817 via a well-oriented hydrogen bond. Another set of different interactions, such as polar, hydrophobic, π-stacking, metal–ligand and electrostatic, were responsible for accommodating avanafil and udenafil. All of the ligands are discussed in detail with consideration of the distinct protein structures, and a profile of the probability of residue–ligand contact is suggested, with the most frequently observed being: Tyr612, His613, Ser661, Thr723, Asp724, Asp764, Leu765, Val782 and Phe786. The molecular interactions displayed herein confirm findings achieved by previous authors and also present new contacts. In addition, the discussion can help researchers obtain a molecular basis for planning new selective PDE5 inhibitors, as well as explain an inhibitor’s experimental assays by considering the specific interactions occurring at the catalytic site.

Phosphodiesterase inhibitors say NO to Alzheimer's disease

Phosphodiesterases (PDEs) consisted of 11 subtypes (PDE1 to PDE11) and over 40 isoforms that regulate levels of cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP), the second messengers in cell functions. PDE inhibitors (PDEIs) have been attractive therapeutic targets due to their involvement in diverse medical conditions, e.g. cardiovascular diseases, autoimmune diseases, Alzheimer's disease (AD), etc. Among them; AD with a complex pathology is a progressive neurodegenerative disorder which affect mostly senile people in the world and only symptomatic treatment particularly using cholinesterase inhibitors in clinic is available at the moment for AD. Consequently, novel treatment strategies towards AD are still searched extensively. Since PDEs are broadly expressed in the brain, PDEIs are considered to modulate neurodegenerative conditions through regulating cAMP and cGMP in the brain. In this sense, several synthetic or natural molecules inhibiting various PDE subtypes such as rolipram and roflumilast (PDE4 inhibitors), vinpocetine (PDE1 inhibitor), cilostazol and milrinone (PDE3 inhibitors), sildenafil and tadalafil (PDE5 inhibitors), etc have been reported showing encouraging results for the treatment of AD. In this review, PDE superfamily will be scrutinized from the view point of structural features, isoforms, functions and pharmacology particularly attributed to PDEs as target for AD therapy.

The Phosphodiesterase-5 Inhibitors and Prostate Cancer – What We Rely Know About It?

Phosphodiesterase-5 inhibitors (PDE5Is) represent a group of drugs that are registered for the treatment of erectile dysfunctions predominantly, but recently also for treatment of pulmonary hypertension and benign prostatic hypertrophy. However, more and more research deals with possible antitumor potential of PDE5Is in different types of cancers, including prostate cancer. Prostate cancer represents the one of the most common carcinoma in the male population, whose incidence is continuously increasing. Early detection combined with radical prostatectomy increases the survival rate, but also it is necessary to keep in mind the quality of life of patients undergoing prostatectomy in light of bladder control and erectile function. Authors of various clinical studies presented the results that often lead to totally opposing conclusions. For example, Chavez and colleagues have shown that use of PDE5Is in men with erectile dysfunction decreases the risk of developing prostate cancer, while, on the other hand, Michl and colleagues pointed out the adversely effect of PDE5Is on biochemical recurrence after bilateral nerve sparing radical prostatectomy. In that sense, the aim of this review was to present as many as possible of existing results dealing with of action of PDE5Is in the field of prostatic carcinoma. Taking into account all presented data, it can be concluded that eff ect of PDE5Is on formation, development and outcome of treatment in patients with prostate carcinoma is very intriguing question, whose response requires additional both experimental and clinical research.

Development and validation of an HPLC-UV method for simultaneous determination of sildenafil and tramadol in biological fluids: Application to drug-drug interaction study

The introduction of sildenafil (SDF) to treat erectile dysfunction has solved a widespread condition with negative on the quality of life. Recently, the co-administration of tramadol (TMD) with SDF to manage premature ejaculation has illegally increased and thus drug-drug interaction studies of these drugs became of great importance. Although certain biological functions have been altered upon co-administration of the two drugs, methods for their determination in vivo to understand their interactions have yet to be published. Herein, therefore, an HPLC method with photometric detection was developed for the determination of a binary mixture of TMD and SDF in rabbit plasma after oral administration. In this study, a reversed-phase chromatography was performed at room temperature on a C₁₈ column with a mobile phase composed of 10 mM Na₂HPO₄ solution (pH 7.5): acetonitrile (45:55, v/v) at a flow rate of 0.8 mL min^-1 using caffeine (CAF) as an internal standard. The detector was set at 220 nm. The total analysis time was 6 min. Calibration graphs were linear in the concentration ranges of 0.1-10 and 0.05-10 μg mL^-1 with a detection limit of 0.05 and 0.02 μg mL^-1 for TMD and SDF, respectively. The method was validated in terms of accuracy, precision, limit of detection and quantitation, recovery, and stability as per US FDA bioanalytical guidelines. In addition, the metabolites N-desmethylsildenafil (UK-103,320) and O-desmethyltramadol were quantified in rabbit plasma after 2 h of oral administration using LC-MS/MS. The simultaneous administration of TMD with SDF has affected peak plasma concentration (C_max), T_max, area under the concentration-time curve (AUC), and the elimination rate constant (K_el) of SDF. The present study is the first to give valuable insights into the drug-drug interaction and the pharmacokinetic implications associated with the co-administration of SDF and TMD.

Accurate and sensitive determination of sildenafil, tadalafil, vardenafil, and avanafil in illicit erectile dysfunction medications and human urine by LC with quadrupole-TOF-MS/MS and their behaviors in simulated gastric conditions

The widespread use of phosphodiesterase-5 inhibitors has attracted broad attention of counterfeiters to develop illicit erectile products with inaccurate amounts, unknown toxicity, and purity of active ingredients. Correspondingly, intake of these products endangers consumer health and needs to be screened for precautionary actions to reduce this risk. Therefore, in this study, a sensitive and rapid analytical method has been developed for simultaneous determination of selected phosphodiesterase-5 inhibitors present in illicit erectile medications and human urine. Quantification of the analytes was performed by liquid chromatography coupled with quadrupole-time-of-flight tandem mass spectrometry system. The chromatographic separation was successfully achieved with a run period of 8 min. Low detection limits were obtained in the range of 1.63-9.81 ng/g with relative standard deviations below 7.72% obtained using the replicate measurements of lowest concentration in calibration plots. The analytical performance of the proposed method proved good linearity, low detection limits, good accuracy and precision with high percent recoveries for human urine samples. Developed method was successfully applied to real samples including four different brands of illicit erectile medications. The results obtained revealed the presence of high levels of sildenafil in analyzed samples. The behaviors of selected phosphodiesterase-5 inhibitors were also studied in simulated gastric conditions.

The Serendipitous Story of Sildenafil: An Unexpected Oral Therapy for Erectile Dysfunction

INTRODUCTION

The serendipitous discovery of sildenafil (Viagra [sildenafil citrate]) as a treatment for erectile dysfunction (ED) is one of the most fascinating drug development stories of our time. When sildenafil was approved by the U.S. Food and Drug Administration in 1998, it revolutionized the treatment protocol for men with ED, once considered a psychological issue or an inevitable part of aging.

AIM

To review the discovery of sildenafil and its role in changing the field of sexual medicine in the context of the epidemiology and history of treatment for ED.

METHODS

For this narrative review, a literature search was conducted to identify essential articles and was supplemented by author observations from a historical perspective.

MAIN OUTCOME MEASURE

A broad overview of ED and its past, current, and future treatments.

RESULTS

ED is a prevalent condition for which medical treatment had been limited to genitally localized interventions, including surgery, vacuum pumps, injectable therapies, and intraurethral suppositories. The discovery of sildenafil provided a safe, oral pharmacotherapy for the treatment of ED, sparking greater understanding of the science behind ED and its role in men's overall health.

CONCLUSION

The approval of sildenafil initiated a global conversation about ED that had profound implications for patients, methods of clinical practice, and academic sexual medicine. These changes will catalyze continued advances in ED treatment. Goldstein I, Burnett AL, Rosen RC, et al. The serendipitous story of sildenafil: an unexpected oral therapy for erectile dysfunction. Sex Med Rev 2019;7:115-128.

Nocturnal penile erections: A retrospective study of the role of RigiScan in predicting the response to sildenafil in erectile dysfunction patients

Sildenafil enhances the nitric oxide–cGMP pathway of erection, which is claimed to have a role in nocturnal penile tumescence and rigidity (NPTR). This study aimed to find whether RigiScan can predict the response to sildenafil among erectile dysfunction (ED) patients and to find which RigiScan parameter produces the best prediction. Medical records of 172 ED patients were revised regarding their full sexual history, standard andrology examination, NPTR monitoring by the RigiScan device, and the degree of response to sildenafil. Of 172 ED patients, 94 patients (54.7%) were sildenafil responders. All RigiScan parameters were higher in the sildenafil responder group. The RigiScan parameters with the most differentiating power between both sildenafil responders and non-responders were base rigidity (AUC 0.860) and then tip rigidity (AUC 0.831). The cut-off value of base and tip rigidity with the highest diagnostic accuracy was 42.5%. This finding was found to be more specific than the sensitivity in predicting a positive response to sildenafil (85.9% vs. 70.2% and 92.3% vs. 59.6%, for base and tip rigidity, respectively). Sildenafil response in ED cases can be predicted through NPTR monitoring using the RigiScan device and ED patients with RigiScan base or tip rigidity less than 42% are not expected to respond well to sildenafil.

Erectile dysfunction and alcohol intake

The objective of this work is to evaluate in a selection of patients with erectile dysfunction the influence of alcohol consumption and the response to alcohol abstinence with and without sildenafil association.

Materials and Methods.

In a population of 150 consecutive patients with erectile dysfunction we studied 50 patients aged between 22 and 77 years (mean 56±14 SD). These 50 patients were divided into three different treatment groups and were screened for three different levels of alcohol risk with two questionnaires. All patients were evaluated with an International Index Erectile Dysfunction (IIEF) questionnaire before and after one month of treatment.

Results.

The 50 patients included 14 patients with high alcohol risk, 34 patients with low alcohol risk and only 2 patients with no alcohol risk. After one month, 29 patients responded to the therapy, and 21 did not respond. The IIEF questionnaire presented a statistically significant difference between the different risk groups before and after treatment (p≤0.05). All the patients were examined with a penile Doppler Ultrasound. Only 10 of them had an abnormal diastolic peak velocity (PDV) and only 1 presented both pathologic systolic peak velocity (PSV) and PDV. These 11 patients did not respond to therapies and 10 of them were at high alcohol risk. The alcohol consumption risk was directly correlated with PDV (p=0.00001; R=0.4).

Conclusions.

The results of this study demonstrated a significant relationship between alcohol consumption and erectile dysfunction. This underlines the important therapeutic issue of alcohol abstinence in treating patients with erectile dysfunction.

Protective effect of co-administration of curcumin and sildenafil in alcohol induced neuropathy in rats

Neuropathic pain associated with chronic alcohol consumption is a medico-socioeconomical problem that affects both central and peripheral nervous system and has no satisfactory treatment till date. The present study was designed to investigate the protective effect of co-administration of curcumin and sildenafil on alcohol induced neuropathic pain in rats. In order to carry out this, ethanol (35% v/v, 10g/kg, p.o.) was administered for 10 weeks to induce neuropathic pain. Curcumin (30 and 60mg/kg, i.p.) and sildenafil (5 and 10mg/kg, i.p.) were given alone and in combination at their lower doses (30mg/kg curcumin and 5mg/kg, sildenafil, i.p.) to investigate the changes in thermal and mechanical hyperalgesia, allodynia and histopathological parameters. Biochemical estimations of thiobarbituric acid reactive species, glutathione and protein was also carried out to evaluate oxidative stress. The results revealed that chronic alcohol consumption for 10 weeks caused significant thermal and mechanical hyperalgesia, allodynia and increased oxidative stress. Individual administration of both the drugs at their low as well as high doses were able to improve the symptoms of alcohol induced neuropathic pain. Whereas co-administration of curcumin and sildenafil at their lower doses itself were found to significantly improve nerve functions, biochemical and histopathological parameters as compared to their individual administration. It is therefore proposed that co-administration of curcumin and sildenafil may bring new dimension towards attenuation of alcohol induced neuropathic pain affecting central as well as peripheral nervous system.

Erectile dysfunction in patients with chronic pain treated with opioids

INTRODUCTION AND OBJECTIVE

Chronic pain is associated with comorbidities that have an impact on the quality of life of patients and, among others, affect their sexual functioning. One of the most relevant side effects of opioid analgesics is erectile dysfunction (ED), due in part to the inhibition of the gonadal-pituitary-hypothalamic axis and the decline in testosterone levels. To evaluate ED and effectiveness of treatment in men with chronic pain treated with long-term opioids.

MATERIAL AND METHODS

Prospective observational study lasting 3 years, where the intensity of pain (visual analogue scale, 0-10cm), erectile function (IIEF-EF, range 1-30 points), quality of life (EQ-VAS, 0-100mm), quality of sexual life (MSLQ-QOL, 0-100 points), anxiety/depression (HAD, 0-21 points) and testosterone levels, was assessed in patients who reported sexual dysfunction (ED or libido modification). A 6-month follow-up was applied to each patient after administering the usual treatment in the Andrology Unit. The study was approved by the Clinical Research Ethics Committee and data were statistically analyzed with the GraphPad Prism 5 software.

RESULTS

ED was observed in 27.6% of patients (n=105, 57±12.2 years, mean dose of morphine equivalent=107.1±107.9mg/day, 84.3% adjuvant analgesics). After 6 months, 42% of patients showed a significant improvement after being treated with iPDE5 (48.5%) and/or testosterone gel (81.8%), with a resolution rate of 31% (p=0.000). A positive correlation was observed between the improvement of IIEF and quality of sexual life (55.5±25.7 points, p=0.000), as well as anxiety (7.4±4.3 points, p=0.048). No significant changes were observed in the levels of testosterone, in the levels of pain nor in the quality of life, which remained moderate.

CONCLUSIONS

Erectile function and quality of sexual life, as well as anxiety, improved in patients treated chronically with opioids after administering andrological treatment. The management of patients with pain should include a review of their sexual health history given the significant emotional impact posed to the patient, the impact on their overall quality of life and its good clinical response to an interdisciplinary treatment.

Angiotensin-(1-7) Downregulates Diabetes-Induced cGMP Phosphodiesterase Activation in Rat Corpus Cavernosum

Molecular mechanisms of the beneficial effects of angiotensin-(1-7), Ang-(1-7), in diabetes-related complications, including erectile dysfunction, remain unclear. We examined the effect of diabetes and/or Ang-(1-7) treatment on vascular reactivity and cyclic guanosine monophosphate (cGMP) phosphodiesterase (PDE) in corpus cavernosum. Male Wistar rats were grouped as (1) control, (2) diabetic (streptozotocin, STZ, treated), (3) control + Ang-(1-7), and (4) diabetic + Ang-(1-7). Following 3 weeks of Ang-(1-7) treatment subsequent to induction of diabetes, rats were sacrificed. Penile cavernosal tissue was isolated to measure vascular reactivity, PDE gene expression and activity, and levels of p38MAP kinase, nitrites, and cGMP. Carbachol-induced vasorelaxant response after preincubation of corpus cavernosum with PE was significantly attenuated in diabetic rats, and Ang-(1-7) markedly corrected the diabetes-induced impairment. Gene expression and activity of PDE and p38MAP kinase were significantly increased in cavernosal tissue of diabetic rats, and Ang-(1-7) markedly attenuated STZ-induced effects. Ang-(1-7) significantly increased the levels of nitrite and cGMP in cavernosal tissue of control and diabetic rats. Cavernosal tissue of diabetic rats had significantly reduced cGMP levels and Ang-(1-7) markedly prevented the STZ-induced cGMP depletion. This study demonstrates that attenuation of diabetes-induced PDE activity might be one of the key mechanisms in the beneficial effects of Ang-(1-7).

The application of color Doppler flow imaging in the diagnosis and therapeutic effect evaluation of erectile dysfunction

We aim to investigate the correlations between hemodynamic parameters, penile rigidity grading, and the therapeutic effects of phosphodiesterase type 5 inhibitors using color Doppler flow imaging after intracavernosal injection in patients with erectile dysfunction. This study involved 164 patients. After intracavernosal injection with a mixture of papaverine (60 mg), prostaglandin E 1 (10 mg), and lidocaine (2%, 0.5-1 ml), the penile vessels were assessed using color Doppler flow imaging. Penile rigidity was classified based on the Erection Hardness Score system as Grades 4, 3, 2 or 1 (corresponding to Schramek Grades V to II). Then, the patients were given oral sildenafil (50-100 mg) and scored according to the International Index of Erectile Function (IIEF-5) questionnaire. The number of patients with penile rigidities of Schramek Grades II to V was 14, 18, 21, and 111, respectively. The IIEF-5 score was positively correlated with the refilling index of the penile cavernosal artery (r = 0.79, P< 0.05), the peak systolic velocity (r = 0.45, P< 0.05), and penile rigidity (r = 0.75, P< 0.05), and was negatively correlated with the end diastolic velocity (r = -0.74, P< 0.05). For patients with erectile dysfunction, both the IIEF-5 score after sildenafil administration, which is correlated with penile rigidity, and the hemodynamic parameters detected using color Doppler flow imaging may predict the effects of phosphodiesterase type 5 inhibitor treatment and could provide a reasonable model for the targeted-treatment of erectile dysfunction.

Pharmacodynamics and Systems Pharmacology Approaches to Repurposing Drugs in the Wake of Global Health Burden

There are emergent needs for cost-effective treatment worldwide, for which repurposing to develop a drug with existing marketing approval of disease(s) for new disease(s) is a valid option. Although strategic mining of electronic health records has produced real-world evidences to inform drug repurposing, using omics data (drug and disease), knowledge base of protein interactions, and database of transcription factors have been explored. Structured integration of all the existing data under the framework of drug repurposing will facilitate decision making. The ability to foresee the need to integrate new data types produced by emergent technologies and to enable data connectivity in the context of human biology and targeted diseases, as well as to use the existing crucial quality data of all approved drugs will catapult the number of drugs being successfully repurposed. However, translational pharmacodynamics databases for modeling information across human biology in the context of host factors are lacking and are critically needed for drug repurposing to improve global public health, especially for the efforts to combat neglected tropic diseases as well as emergent infectious diseases such as Zika or Ebola virus.

Comparing the effects of treatment with sildenafil and cognitive-behavioral therapy on treatment of sexual dysfunction in women: a randomized controlled clinical trial

Background

Sexual dysfunction in women is prevalent and common in women after menopause. Many attempts to treat patients with sexual dysfunction by cognitive-behavioral therapy (CBT) methods. But to the best of our knowledge, there has been no study that compared these two methods.

Objective

The aim of this study was to assess and compare the effects of sildenafil and cognitive-behavioral therapy on treatment of sexual dysfunction in women.

Methods

In this randomized, controlled, clinical trial, 86 women with arousal and orgasm dysfunction were surveyed. The patients were divided into two groups, i.e., sildenafil and CBT groups. The patients in the sildenafil group were treated by 50 mg of oral sildenafil one hour before intercourse, and the other group had weekly sessions of CBT for eight weeks. Sexual dysfunctions were evaluated by the Female Sexual Function Index (FSFI), a sexual satisfaction questionnaire, and the Enrich marital satisfaction scale.

Results

The mean age of the participants was 33.14 ± 7.34 years. The mean scores for female sexual function index, sexual satisfaction, and the Enrich marital satisfaction scale were increased in both groups during treatment (p < 0.001). It was found that cognitive-behavioral therapy compared to treatment with sildenafil increased all subscales, except arousal, orgasm, and lubrication.

Conclusion

Cognitive-behavioral therapy is more effective than treatment with sildenafil for improving female sexual function.

Clinical trial registration

The trial was registered at the Iranian Registry of Clinical Trials (http://www.irct.ir) with the IRCT ID: IRCT2014070318338N1.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Cyclic nucleotide phosphodiesterases in heart and vessels: A therapeutic perspective

Cyclic nucleotide phosphodiesterases (PDEs) degrade the second messengers cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), thereby regulating multiple aspects of cardiac and vascular muscle functions. This highly diverse class of enzymes encoded by 21 genes encompasses 11 families that are not only responsible for the termination of cyclic nucleotide signalling, but are also involved in the generation of dynamic microdomains of cAMP and cGMP, controlling specific cell functions in response to various neurohormonal stimuli. In the myocardium and vascular smooth muscle, the PDE3 and PDE4 families predominate, degrading cAMP and thereby regulating cardiac excitation-contraction coupling and smooth muscle contractile tone. PDE3 inhibitors are positive inotropes and vasodilators in humans, but their use is limited to acute heart failure and intermittent claudication. PDE5 is particularly important for the degradation of cGMP in vascular smooth muscle, and PDE5 inhibitors are used to treat erectile dysfunction and pulmonary hypertension. There is experimental evidence that these PDEs, as well as other PDE families, including PDE1, PDE2 and PDE9, may play important roles in cardiac diseases, such as hypertrophy and heart failure, as well as several vascular diseases. After a brief presentation of the cyclic nucleotide pathways in cardiac and vascular cells, and the major characteristics of the PDE superfamily, this review will focus on the current use of PDE inhibitors in cardiovascular diseases, and the recent research developments that could lead to better exploitation of the therapeutic potential of these enzymes in the future.

The potential role of trimethoprim-sulfamethoxazole in the treatment of drug-resistant tuberculosis

Tuberculosis (TB) remains a serious public health threat worsened by emerging drug resistance. Mycobacterium tuberculosis has become resistant not only to front-line drugs but also to second-line antimicrobials directed at drug-resistant TB. Renewed efforts are devoted for the development of new antibiotics active against TB. Also, repurposing of other antibiotics is being explored to shorten the time to develop new drugs against M. tuberculosis. As a result, trimethoprim-sulfamethoxazole (SXT) has emerged as a potential new option to treat drug-resistant TB. SXT has been found to be surprisingly active against drug-resistant M. tuberculosis, not only in vitro but also in vivo. The potential role of SXT for the treatment of multidrug resistant/extensively drug resistant TB might be explored in further clinical evaluations.

Patient Insight and Treatment Expectations in Erectile Dysfunction

In the literature, a strong preference towards pharmacological management with oral phosphodiesterase type 5 (PDE5) inhibitors has been demonstrated in men with erectile dysfunction (ED) versus other methods. However, following pharmacological management, a large proportion of men with ED discontinue treatment prematurely. Therefore, a better understanding of the expectations from, and demands on modern ED management from both the patients and their partners is needed in order to identify factors that may improve outcomes, patient adherence, and patient satisfaction with therapy. Thus, we will present new findings on patient and partner satisfaction and preferences, and discuss how the current pharmacological armamentarium can answer these needs.

Usage and perceptions of phosphodiesterase type 5 inhibitors among the male partners of infertile couples

OBJECTIVE

We aimed to investigate the prevalence of erectile dysfunction (ED) and the usage of phosphodiesterase type 5 (PDE5) inhibitors for ED treatment in infertile couples.

METHODS

A total of 260 male partners in couples reporting infertility lasting at least 1 year were included in this study. In addition to an evaluation of infertility, all participants completed the International Index of Erectile Function (IIEF)-5 questionnaire to evaluate their sexual function. The participants were asked about their use of PDE5 inhibitors while trying to conceive during their partner's ovulatory period and about their concerns regarding the risks of PDE5 inhibitor use to any eventual pregnancy and/or the fetus.

RESULTS

Based on the IIEF-5 questionnaire, 41.5% of the participants (108/260) were classified as having mild ED (an IIEF-5 score of 17-21), while 10.4% of the participants (27/260) had greater than mild ED (an IIEF-5 score of 16 or less). The majority (74.2%, 193/260) of male partners of infertile couples had a negative perception of the safety of using a PDE5 inhibitor while trying to conceive. Only 11.1% of men (15/135) with ED in infertile couples had used a PDE5 inhibitor when attempting conception.

CONCLUSION

ED was found to be common in the male partners of infertile couples, but the use of PDE5 inhibitors among these men was found to be very low. The majority of male partners were concerned about the risks of using PDE5 inhibitors when attempting to conceive. Appropriate counseling about this topic and treatment when necessary would likely be beneficial to infertile couples in which the male partner has ED.

Pharmacophore generation and atom based 3D-QSAR of quinoline derivatives as selective phosphodiesterase 4B inhibitors

Reported PDE4B inhibitors were used to design QSAR based pharmacophore model. Using developed pharmacophore model, virtual screening was performed followed by cross-docking to identify novel PDE4B specific inhibitors.