In vitro sildenafil citrate use as a sperm motility stimulant

Sildenafil citrate ameliorates the adverse effects of cryopreservation on sperm quality in asthenozoospermic men

In this study, the effects of Sildenafil Citrate on the sperm quality during cryopreservation in the asthenozoospermic patients were investigated for the first time. Thirty semen samples were collected from asthenozoospermic patients and each sample was divided into 3 groups: Control (fresh), Freeze and Freeze + Sildenafil. In each groups the sperm parameters, DNA fragmentation, acrosome integrity, protamine deficiency, mitochondrial membrane potential, plasma membrane integrity, the expression of Bcl-2 and HSP70 genes, as well as the level of Tumor necrosis factor-alpha, Malondialdehyde and antioxidants (Catalase, Glutathione, and Superoxide dismutase) in sperm were assessed. Data were analyzed statistically using Repeated Measure Analysis. The level of Malondialdehyde and Tumor necrosis factor-alpha, morphological abnormalities, DNA fragmentation, protamine deficiency and the expression of Bcl-2 and HSP70 genes increased significantly in the Freeze group compared to the Control, while the level of sperm parameters and antioxidants, plasma membrane integrity, mitochondrial membrane potential and acrosomal integrity significantly decreased. In the Freeze + Sildenafil group, compared to the Freeze group, all the mentioned parameters were significantly reversed except for the acrosomal integrity (decreased even more) and the expression of Bcl-2 (increased even more) and HSP70 genes (with no change). Although adding Sildenafil to the freezing medium decreased the adverse effects of freezing on the sperm of asthenozoospermic patients and improved sperm quality, but it also caused premature acrosome reaction. Therefore, we suggest the consumption of Sildenafil along with another antioxidant, to benefit from the favorable effects of Sildenafil as well as to maintain the integrity of the sperm acrosome.

Once upon a Testis: The Tale of Cyclic Nucleotide Phosphodiesterase in Testicular Cancers

Phosphodiesterases are key regulators that fine tune the intracellular levels of cyclic nucleotides, given their ability to hydrolyze cAMP and cGMP. They are critical regulators of cAMP/cGMP-mediated signaling pathways, modulating their downstream biological effects such as gene expression, cell proliferation, cell-cycle regulation but also inflammation and metabolic function. Recently, mutations in PDE genes have been identified and linked to human genetic diseases and PDEs have been demonstrated to play a potential role in predisposition to several tumors, especially in cAMP-sensitive tissues. This review summarizes the current knowledge and most relevant findings regarding the expression and regulation of PDE families in the testis focusing on PDEs role in testicular cancer development.

PDE5 inhibitors and male reproduction: Is there a place for PDE5 inhibitors in infertility clinics or andrology laboratories?

The objective of this review study is to evaluate the therapeutic role of PDE5 inhibitors (PDE5is) in the amelioration of oligoasthenospermia in infertile males. PDE5is have a beneficial influence on the secretory function of the Leydig and Sertoli cells, the biochemical environment within the seminiferous tubule, the contractility of the testicular tunica albuginea, and the prostatic secretory function. In several studies, the overall effect of sildenafil and vardenafil increased quantitative and qualitative sperm motility. Furthermore, some studies indicate that PDE5is influence positively the sperm capacity to undergo capacitation under biochemical conditions that are known to induce the sperm capacitation process. Additional research efforts are necessary in order to recommend unequivocally the usage of sildenafil, vardenafil, or avanafil for the alleviation of male infertility.

An acute oral administration of Sildenafil in asthenozoospermic patients improves sperm motility after density gradient centrifugation

Objective:

Investigate the possible effect of an acute sildenafil dose in asthenozoospermic patients.

Methods:

We ran this experimental, descriptive, prospective and non-blinded study in 32 patients diagnosed with asthenozoospermia according to the WHO criteria, after two consecutive semen analyses (samples 1 and 2), and we asked them to provide a new semen sample two weeks after the initial exams (sample 3). One hour prior to the semen collection, we gave the patients 100mg oral sildenafil. Samples 2 and 3 were allowed to liquefy and density gradients centrifugation was performed. We assessed sperm motility by Computer-assisted sperm analysis (CASA).

Results:

There were no significant differences between the samples obtained before (sample2) or after sildenafil administration (sample3). However, a single oral 100 mg sildenafil dose in asthenozoospermic patients increase the percentage of motile sperm recovered after density gradient centrifugation.

Conclusions:

An acute administration of sildenafil enhances sperm recovery after density gradient centrifugation in asthenozoospermic patients, and it may produce more available mobile sperm to perform intra uterine insemination or to improve the chances of success in this procedure. This approach may be used as an alternative strategy in assisted reproductive programs. Sildenafil was well tolerated and no patient was withdrawn from the study due to adverse events attributed to sildenafil.

Effect of phosphodiesterase type 5 inhibitors on sperm motility and acrosome reaction: An in vitro study

Purpose

Phosphodiesterase type 5 (PDE5) inhibitors are effective treatments for erectile dysfunction, and several recent studies have reported positive effects of PDE5 inhibitors on semen parameters as well. However, the data are still controversial. We investigated the effect of PDE5 inhibitors on sperm function by analyzing sperm motility and acrosome reaction.

Materials and Methods

This study included young healthy men who underwent fertility evaluation; 32 cases were finally included. Men were excluded if they used a PDE5 inhibitor within 2 weeks or if they had insufficient semen volume (≤2 mL), leukocytospermia, or a genitourinary infection. Changes in sperm motility and acrosome reaction were determined after in vitro exposure to the maximal semen concentration of oral intake of sildenafil (100 mg) or tadalafil (20 mg).

Results

Mean age of the participants was 35.4±4.9 years, mean sperm concentration was 68.7±32.4 ×10⁶/mL, and mean sperm motility was 50.38%±8.41%. All three groups (control, sildenafil, tadalafil) experienced trends of decreased average sperm motility over time, but these changes were not significant. There were no significant differences between the three groups in the acrosome reaction after 120 minutes of drug exposure, either. The maximal semen concentration of oral intake of sildenafil (100 mg) or tadalafil (20 mg) did not substantially affect sperm motility or acrosome reaction.

Conclusions

Our results suggest that on-demand use of a PDE5 inhibitor is safe and useful for the male partner of an infertile couple; however, further studies are warranted for daily PDE5 inhibitor use.

The Effect of Oral Phosphodiesterase-5 Inhibitors on Sperm Parameters: A Meta-analysis and Systematic Review

OBJECTIVE

To perform a systematic review and meta-analysis to evaluate the effect of phosphodiesterase-5 (PDE5) inhibitors on sperm parameters.

METHODS

A systematic literature search was performed. Mean value and its standard deviation (mean ± standard deviation) were used to perform quantitative analysis. Statistic heterogeneity scores were assessed with the standard Cochran Q test and I2 statistic. All statistical analyses were conducted by RevMan 5.3.

RESULTS

Eleven studies embraced a total of 1317 participants and 19 subgroups or trials were included. Acute administration of PDE5 inhibitors had no effect on semen volume (mean value [MD] = 0.26; 95% confidence interval [CI]: 0.00-0.48) and sperm concentration (MD = 2.04; 95%CI: -2.95 to 7.04). However, the percentage of motile spermatozoa (MD = 7.05; 95%CI: 2.59-11.51), the percentage of total progressive motility (MD = 6.23; 95%CI: 2.43-10.04), and rapid progressive motility (MD = 3.11; 95%CI: 0.23-5.99) were increased after oral PDE5 inhibitors treatment. Interestingly, these significant changes were observed only in infertile men but not in normal patients (MD = 6.89, P < .001 vs MD = 0.67, P = .71; MD = 6.64, P = .001 vs MD = 2.11, P > .05; and MD = 3.89, P = .04 vs MD = 0.92, P = .59, respectively). The percentage of morphologically normal spermatozoa also increased in infertile men (MD = 12.15; 95%CI: 5.16-19.15). Limited evidence showed the linearity, abnormal forms of spermatozoa, as well as reproductive hormones (total testosterone, free testosterone, luteinizing hormone, and follicle-stimulating hormone) did not benefit from PDE5 inhibitors treatment.

CONCLUSION

Oral PDE5 inhibitors treatment could modestly increase the sperm motility and morphology in infertile men.

Useful Implications of Low-dose Long-term Use of PDE-5 Inhibitors

INTRODUCTION

Phosphodiesterase type 5 (PDE-5) hydrolyzes cyclic guanylate monophosphate (cGMP) specifically to 5' GMP, promoting successful corporeal vascular relaxation and penile erection during sexual stimulation. Oral PDE-5 inhibitors such as sildenafil, vardenafil, tadalafil, and avanafil have provided noninvasive, effective, well-tolerated treatment for erectile dysfunction (ED) patients and, at the same time, stimulated both academic and clinical interests. Lately, some oral PDE-5 inhibitors were released as low-dose preparations with the concept of potential daily administration and long-term use.

AIM

To highlight the possible potential implications of low-dose long-term use of PDE-5 inhibitors.

METHOD

A systematic review was carried out until December 2015 based on a search of all concerned articles in MEDLINE, medical subjects heading (MeSH) databases, Scopus, The Cochrane Library, EMBASE, and CINAHL databases without language restriction. Key words used to assess the outcome and estimates for concerned associations were: PDE-5 inhibitors; erectile dysfunction; low-dose; long-term; sildenafil; tadalafil; vardenafil; avanafil.

MAIN OUTCOME MEASURES

Demonstrating different implications for low-dose long-term use of PDE-5 inhibitors.

RESULTS

Low-dose and/or long-term use of PDE-5 inhibitors was shown to put forth beneficial sound effects in different medical implications with potentials that could be extended for different utilities. These implications included sexual, urogenital, cardiovascular, pulmonary, cutaneous, gastrointestinal, and reproductive, as well as neurological disorders. However, it is evident that most potential appliances were carried out experimentally on preclinical studies with off-label indications.

CONCLUSION

Making use of and exploring low-dose and/or long-term use of several PDE-5 inhibitors for their possible implications seem to be valuable in different medical disorders. Increased knowledge of the drug characteristics, comparative treatment regimens, optimal prescribing patterns, and well-designed clinical trials are needed before these agents can be recommended for use.

Effect of vardenafil on semen parameters in infertile men: a pilot study evaluating short-term treatment

BACKGROUND

Severeal in vivo and in vitro studies have been carried out in order to evaluate the efficacy of long-term treatment with phosphodiesterase type-5 (PDE5) inhibitors (PDE5i) on spermatogenesis, but the results are still controversial.

AIM

To evaluate the effects of vardenafil on seminal parameters of infertile men after a short-term treatment.

MATERIALS/SUBJECTS AND METHODS

A total of 205 male subjects were randomized to receive a single dose of vardenafil 10 mg (73 men, group B), a single dose of vardenafil 10 mg every other day for 15 days (67 men, group C), and no treatment (65 men, group A). Semen parameters were evaluated before and after the end of the treatment in each of group A, B, and C, respectively. Additionally, an IIEF- 5 questionnaire was administered to all patients with erectile dysfunction (ED) before and after each treatment period.

RESULTS

The semen parameters in groups B and C has shown a significant increase in percentage forward motility after vardenafil administration as compared with baseline (p<0.001). In group C, we observed an increase in the mean semen volume and an improvement in the mean total sperm concentration (p<0.001) as compared with baseline.

CONCLUSIONS

We showed the efficacy of vardenafil in the treatment of ED and, on a large series of infertile patients, the positive effect on sperm motility after a single-dose administration. It also showed that after 15 days of treatment on alternate days is also achieved an improvement in sperm concentration.

Hormesis and medicine

Evidence is presented which supports the conclusion that the hormetic dose-response model is the most common and fundamental in the biological and biomedical sciences, being highly generalizable across biological model, endpoint measured and chemical class and physical agent. The paper provides a broad spectrum of applications of the hormesis concept for clinical medicine including anxiety, seizure, memory, stroke, cancer chemotherapy, dermatological processes such as hair growth, osteoporosis, ocular diseases, including retinal detachment, statin effects on cardiovascular function and tumour development, benign prostate enlargement, male sexual behaviours/dysfunctions, and prion diseases.

Oral phosphodiesterase-5 inhibitors and sperm functions

This review aims to elucidate the possible effects of phosphodiesterase-5 (PDE5) inhibitors on sperm functions. PDEs hydrolyze cyclic nucleotides, and together with adenylyl and guanylyl cyclase, which catalyze the formation of cAMP and cGMP, regulate the levels of these second messengers in cells. cGMP-specific PDE5 is one of the PDEs that have been intensively studied because of its fundamental pharmacological relevance, as oral PDE5 inhibitors are used successfully in treating erectile dysfunction. In addition, they have shown diverse beneficial actions in different disease categories. Specific relevance of the cGMP system in reproductive functions has been recently proposed. Its use was shown to be devoid of effects on semen volume, concentration, sperm membrane integrity or sperm penetration assay. Most available studies demonstrated a significant increase in sperm motility and viability both in vivo and in vitro, which seems to be enhanced at low doses and reduced at high concentrations. Also, these molecules showed a role in capacitation and a debated one concerning acrosome reaction. However, due to the relative short period since the launching of oral PDE5 inhibitors, more investigations should be carried out in wider scales to assess their effect(s) on variant sperm function that could be beneficial as potential therapeutic approaches.

Oral phosphodiesterase type 5 inhibitors: nonerectogenic beneficial uses

INTRODUCTION

Phosphodiesterase type 5 (PDE5) hydrolyses cyclic guanylate monophosphate (cGMP) specifically to 5' GMP. PDE5 inhibitors were a breakthrough medication that addressed a previously unfulfilled medical need. They promoted vascular relaxation in the corpora cavernosa and penile erection during sexual stimulation. Sildenafil, vardenafil, and tadalafil were approved then introduced as effective treatments for male erectile dysfunction. This impact has stimulated academic, clinical, and industrial research.

AIM

To highlight the nonerectogenic beneficial uses of oral PDE5 inhibitors.

METHOD

A systematic review of published studies in this affair based on a Pubmed and medical subject heading databases search of all concerned articles.

MAIN OUTCOME MEASURES

Demonstrated beneficial as well as applicable uses of oral PDE5 inhibitors.

RESULTS

As chemical molecules, these drugs were shown to exert potential nonerectogenic beneficial effects. They showed efficacy as a useful adjunct in the management of pulmonary hypertension. Additional uses were extended to different utilities: essential hypertension, benign prostatic hyperplasia, gastrointestinal disorders, endothelial dysfunction, female sexual dysfunction, genital blood flow, exercise capacity, Raynaud's phenomenon, sperm motility, etc.

CONCLUSION

Exploring PDE5 inhibitors for their possible medical applications in diverse specialties seems to be beneficial in making use of these molecules for the welfare of humanity.

Effects of phosphodiesterase-5 inhibitors on sperm parameters and fertilizing capacity

The aim of this review study is to elucidate the effects that phosphodiesterase 5 (PDE5) inhibitors exert on spermatozoa motility, capacitation process and on their ability to fertilize the oocyte. Second messenger systems such as the cAMP/adenylate cyclase (AC) system and the cGMP/guanylate cyclase (GC) system appear to regulate sperm functions. Increased levels of intracytosolic cAMP result in an enhancement of sperm motility and viability. The stimulation of GC by low doses of nitric oxide (NO) leads to an improvement or maintenance of sperm motility, whereas higher concentrations have an adverse effect on sperm parameters. Several in vivo and in vitro studies have been carried out in order to examine whether PDE5 inhibitors affect positively or negatively sperm parameters and sperm fertilizing capacity. The results of these studies are controversial. Some of these studies demonstrate no significant effects of PDE5 inhibitors on the motility, viability, and morphology of spermatozoa collected from men that have been treated with PDE5 inhibitors. On the other hand, several studies demonstrate a positive effect of PDE5 inhibitors on sperm motility both in vivo and in vitro. In vitro studies of sildenafil citrate demonstrate a stimulatory effect on sperm motility with an increase in intracellular cAMP suggesting an inhibitory action of sildenafil citrate on a PDE isoform other than the PDE5. On the other hand, tadalafil's actions appear to be associated with the inhibitory effect of this compound on PDE11. In vivo studies in men treated with vardenafil in a daily basis demonstrated a significantly larger total number of spermatozoa per ejaculate, quantitative sperm motility, and qualitative sperm motility; it has been suggested that vardenafil administration enhances the secretory function of the prostate and subsequently increases the qualitative and quantitative motility of spermatozoa. The effect that PDE5 inhibitors exert on sperm parameters may lead to the improvement of the outcome of assisted reproductive technology (ART) programs. In the future PDE5 inhibitors might serve as adjunct therapeutical agents for the alleviation of male infertility.

Daily vardenafil for 6 months has no detrimental effects on semen characteristics or reproductive hormones in men with normal baseline levels

PURPOSE

Phosphodiesterase type 5 inhibitors are the first choice therapy in the treatment of erectile dysfunction. Many men in their reproductive years are now using phosphodiesterase type 5 inhibitors. The purpose of this study was to determine the effects of 6 months of treatment with 20 mg vardenafil, compared with 100 mg sildenafil and placebo, on semen characteristics and reproductive hormones in men with and without erectile dysfunction.

MATERIALS AND METHODS

This was a randomized, double-blind, placebo controlled, parallel group, multicenter study. A total of 200 men with or without erectile dysfunction, able to produce semen samples without erectile dysfunction therapy, 25 to 64 years old, were randomized to daily treatment with vardenafil, sildenafil or placebo for 6 months. The primary variable was the percentage of vardenafil treated individuals with a 50% or greater decrease in mean sperm concentration from baseline to 6-month last observation carried forward, compared with placebo treated individuals.

RESULTS

The between group difference (vardenafil minus placebo) in the percentage of patients with 50% or greater decrease in sperm concentration (baseline to 6 months last observation carried forward) was 0.07% (95% CI, -8.53% to 8.39%). Vardenafil also had no clinically significant effects on any other semen parameters, or on levels of reproductive hormones, when compared with placebo. Similar data were observed with sildenafil.

CONCLUSIONS

This study demonstrated that vardenafil had no adverse effects on sperm concentration, compared with sildenafil and placebo, when administered daily at the maximum recommended dose for 6 months. Specifically, use of vardenafil for 6 months does not impair sperm concentration, total sperm count per ejaculate, or sperm morphology and motility. Levels of reproductive hormones were also unaffected.