Phosphodiesterase 5 (PDE-5) inhibitors (sildenafil, tadalafil, and vardenafil) effects on esophageal motility: a systematic review.

BACKGROUND: Esophageal motility disorders are a group of disorders associated with dysfunctional swallowing resulting from impaired neuromuscular coordination. Phosphodiesterase 5 (PDE-5) inhibitors induce smooth relaxation and are proposed as a treatment option for esophageal motility disorders such as achalasia. METHODS: This study is conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We systematically searched MEDLINE/ PubMed, Scopus, EMBASE, and Web of Science databases for esophageal outcomes of individuals treated with PDE5 inhibitors. A random effect meta-analysis was conducted. RESULTS: A total of 14 studies were included. They were conducted in different countries, with Korea and Italy having the highest number of articles. The main drug assessed was sildenafil. PDE-5 inhibitors resulted in a significant reduction in lower esophageal sphincter pressure (SMD - 1.69, 95% CI: -2.39 to -0.99) and the amplitude of contractions (SMD - 2.04, 95% CI: -2.97 to -1.11). Residual pressure was not significantly different between the placebo and sildenafil groups (SMD - 0.24, 95% CI: -1.20 to 0.72). Furthermore, a recent study reported contractile integral, stating that ingestion of sildenafil leads to a significant reduction in distal contractile integral and a significant increase in proximal contractile integral. CONCLUSION: PDE-5 inhibitors significantly reduce LES resting pressure and esophageal peristaltic vigor, decreasing esophageal body contractility and contraction reserve. Therefore, using these drugs in patients affected by esophageal motility disorders may potentially improve their condition regarding symptom relief and prevention of further associated complications. Future reports investigating larger sample size is necessary in order to establish definite evidence regarding the efficacy of these drugs.

Statins synergize with phosphodiesterase type 5 inhibitors but not with selective estrogen receptor modulators to prevent myofibroblast transformation in an in vitro model of Peyronie's disease.

BACKGROUND: Peyronie's disease (PD) is a fibrotic disorder characterized by plaque formation in the tunica albuginea (TA) of the penis, and we have previously shown that inhibition of transformation of TA-derived fibroblasts to myofibroblasts using a combination phosphodiesterase type 5 (PDE5) inhibitors and selective estrogen receptor modulators (SERMs) is effective in slowing the progression of early PD. AIM: The study sought to investigate whether combinations of statins with PDE5 inhibitors or SERMs would affect myofibroblast transformation in vitro. METHODS: Primary fibroblasts were isolated from TA of patients with PD and stimulated with transforming growth factor ß1 in the absence and presence of a range of concentrations of statins, PDE5 inhibitors, SERMs, and their combinations for 72 hours before quantifying α-smooth muscle actin using in-cell enzyme-linked immunosorbent assay. OUTCOMES: The prevention of transforming growth factor ß1-induced transformation of TA-derived fibroblasts to myofibroblasts was measured in vitro. RESULTS: Statins (simvastatin, lovastatin) inhibited myofibroblast transformation in a concentration-dependent manner with half maximal inhibitory concentration values of 0.77 ± 0.07 µM and 0.8 ± 0.13 µM, respectively. Simvastatin inhibited myofibroblast transformation in a synergistic fashion when combined with vardenafil (a PDE5 inhibitor; log alpha >0). Combination of tamoxifen (a SERM) and simvastatin did not show synergy (log alpha <0). When 3 drugs (simvastatin, vardenafil, and tamoxifen) were combined, the effect was not synergistic, but rather was additive. CLINICAL IMPLICATIONS: A combination of a statin with a PDE5 inhibitor might be useful in the clinic to slow the progression of the disease in patients with early PD; however, caution should be taken with such a combination because of the reported myopathy as a side effect. STRENGTHS AND LIMITATIONS: The use of primary human cells from patients with PD is a strength of this study. The mechanisms by which these drug classes exert synergy when used in combination was not investigated. CONCLUSION: This is the first demonstration of an antifibrotic synergy between statins and PDE5 inhibitors.

Intracellular cGMP increase is not involved in thyroid cancer cell death.

INTRODUCTION: Type 5 phosphodiesterase (PDE5) inhibitors (PDE5i) lead to intracellular cyclic-guanosine monophosphate (cGMP) increase and are used for clinical treatment of erectile dysfunction. Studies found that cGMP may up/downregulate the growth of certain endocrine tumor cells, suggesting that PDE5i could impact cancer risk. AIM: We evaluated if PDE5i may modulate thyroid cancer cell growth in vitro. MATERIALS AND METHODS: We used malignant (K1) and benign (Nthy-ori 3-1) thyroid cell lines, as well as the COS7 cells as a reference model. Cells were treated 0-24 h with the PDE5i vardenafil or the cGMP analog 8-br-cGMP (nM-µM range). cGMP levels and caspase 3 cleavage were evaluated by BRET, in cGMP or caspase 3 biosensor-expressing cells. Phosphorylation of the proliferation-associated extracellularly-regulated kinases 1 and 2 (ERK1/2) was evaluated by Western blotting, while nuclear fragmentation by DAPI staining. Cell viability was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RESULTS: Both vardenafil and 8-br-cGMP effectively induced dose-dependent cGMP BRET signals (p≤0.05) in all the cell lines. However, no differences in caspase 3 activation occurred comparing PDE5i-treated vs untreated cells, at all concentrations and time-points tested (p>0.05). These results match those obtained upon cell treatment with 8-br-cGMP, which failed in inducing caspase 3 cleavage in all the cell lines (p>0.05). Moreover, they reflect the lack of nuclear fragmentation. Interestingly, the modulation of intracellular cGMP levels with vardenafil or the analog did not impact cell viability of both malignant and benign thyroid tumor cell lines, nor the phosphorylation of ERK1/2 (p>0.05). CONCLUSIONS: This study demonstrates that increased cGMP levels are not linked to cell viability or death in K1 and Nthy-ori 3-1 cell lines, suggesting that PDE5i do not impact the growth of thyroid cancer cells. Since different results were previously published, further investigations are recommended to clarify the impact of PDE5i on thyroid cancer cells.

Changes in Left Ventricular Ejection Fraction and Oxidative Stress after Phosphodiesterase Type-5 Inhibitor Treatment in an Experimental Model of Retrograde Rat Perfusion.

Background and objectives: Taking into consideration the confirmed role of oxidative stress in ischemia/reperfusion injury and the insufficiency in knowledge regarding the phosphodiesterase 5 (PDE5)-mediated effects on the cardiovascular system, the aim of our study was to investigate the influence of two PDE5 inhibitors, tadalafil and vardenafil, with or without the addition of N(G)-nitro-L-arginine methyl ester (L-NAME), on oxidative stress markers, coronary flow and left ventricular function, both ex vivo and in vivo. Methods: This study included 74 male Wistar albino rats divided into two groups. In the first, 24 male Wistar rats were orally treated with tadalafil or vardenafil for four weeks in order to perform in vivo experiments. In the second, the hearts of 50 male Wistar albino were excised and perfused according to the Langendorff technique in order to perform ex vivo experiments. The hearts were perfused with tadalafil (10, 20, 50 and 200 nM), vardenafil (10, 20, 50 and 200 nM) and a combination of tadalafil/vardenafil and L-NAME (30 µM). The CF and oxidative stress markers, including nitrite bioaviability (NO2-), superoxide anion radical (O2-), and the index of lipid peroxidation, were measured in coronary effluent. Results: The L-arginin/NO system acts as the mediator in the tadalafil-induced effects on the cardiovascular system, while it seems that the vardenafil-induced increase in CF was not primarily induced by the NO system. Although tadalafil induced an increase in O2- in the two lowest doses, the general effects of both of the applied PDE5 inhibitors on oxidative stress were not significant. The ejection function was above 50% in both groups. Conclusions: Our results showed that both tadalafil and vardenafil improved the coronary perfusion of the myocardium and LV function by increasing the EF.

The PDE5 inhibitor, vardenafil, ameliorates progressive pathological changes in a focal segmental glomerulosclerosis mouse model.

AIMS: Phosphodiesterase 5 inhibitors (PDE5is) inhibit the hydrolysis of cyclic guanosine 5'-monophosphate in smooth muscle cells and are a widely known treatment for erectile dysfunction. Accumulating evidence also suggests that PDE5is exhibit potential benefits in cardiovascular and chronic kidney diseases. In this study, we examined the therapeutic effects of a PDE5i, vardenafil (VAR), in a focal segmental glomerulosclerosis (FSGS) mouse model. MATERIALS AND METHODS: FSGS was induced in BALB/c mice by the intravenous administration of Adriamycin (AD, 11 mg/kg of body weight). After 24 h, VAR (at 12.5 µg/ml) was given in drinking water ad libitum until the animals were sacrificed. At the end of the experiment, plasma and kidney samples were harvested to evaluate clinical parameters, histopathological changes, and alterations in transcriptome and protein expressions. KEY FINDINGS: In this study, VAR treatment attenuated the deterioration of proteinuria, renal dysfunction, and hypercholesterolemia in AD-induced FSGS. Treatment with VAR exhibited reductions in the severity of both glomerulosclerosis and tubulointerstitial injury in the histological analysis. In addition to relieving AD-induced podocyte loss, VAR also preserved endothelial cells in glomerular capillaries and ameliorated the accumulation of collagen fibers in the mesangial area and Bowman's capsule basement membrane. In addition, VAR showed an ability to suppress transforming growth factor-ß-induced fibroblast-to-myofibroblast transdifferentiation. SIGNIFICANCE: Our data suggest that VAR exhibited reno-therapeutic effects via attenuating podocyte loss, preserving the integrity of the glomerular vasculature, and ameliorating fibrotic changes. These findings suggest that PDE5is might be a promising treatment modality for nephrotic syndrome.

Stimulating effects of vardenafil, tadalafil, and udenafil on vascular endothelial growth factor, angiogenesis, vitamin D3, bone morphogenic proteins in ovariectomized rats.

OBJECTIVE: This study investigated the effect of vardenafil, tadalafil, and udenafil from phosphodiesterase-5 inhibitors (PDE-5Is) on bone morphogenic-protein (BMP)2 and 4 levels, along with angiogenesis in ovariectomized rat's kidney. METHOD: Rats were randomly divided into five groups (n = 10). Sham: abdomen was opened, and closed. OVX: ovaries were removed. OVX + vardenafil, OVX + tadalafil, and OVX + udenafil groups: ovaries were removed and closed, and after 6 months from postoperative, 10 mg/kg of vardenafil, tadalafil, and udenafil were administrated as daily a single-dose for 60 days, respectively. Histopathologic and immunohistochemical examinations were performed for angiogenesis, and biochemical analysis for vascular endothelial growth-factor (VEGF), VitaminD3, BMP2 and 4 levels in rat's kidney. RESULTS: VEGF, BMP2 and 4, VitaminD3, and angiogenesis were high in the all inhibitor groups compared with the sham and OVX (p < .05). However, BMP4 levels were only high in the OVX + tadalafil group (p < .05). CONCLUSION: The results indicated that vardenafil, udenafil, and especially tadalafil increased VEGF, BMP2, and VitaminD3 levels.

Phosphodiesterase (PDE) 5 inhibitors sildenafil, tadalafil and vardenafil impact cAMP-specific PDE8 isoforms-linked second messengers and steroid production in a mouse Leydig tumor cell line.

Type 5 phosphodiesterase (PDE5) blockade by inhibitors (PDE5i) results in intracellular cyclic guanosine monophosphate (cGMP) increase and smooth muscle relaxation and are used for the treatment of men erectile dysfunction. Although they have high specificity for PDE5, these inhibitors are suspected to cross-interact also with cyclic adenosine monophosphate (cAMP)-specific PDEs, inducing the intracellular accumulation of this cyclic nucleotide and related testosterone increase, positively impacting male reproductive parameters. However, the link between the use of PDE5i and the activation of cAMP-mediated steroidogenesis is still unclear. We have investigated whether three PDE5i, sildenafil, tadalafil and vardenafil, cross-interacts with the high affinity cAMP-specific enzymes type 8A and 8B PDEs (PDE8A and PDE8B), in live, transfected mouse Leydig tumor (mLTC1) and human embryonic kidney (HEK293) cell lines in vitro. The PDE5i-induced production of cAMP-dependent testosterone and its precursor progesterone was evaluated as well. We have developed PDE8A/B biosensors and modified cyclic nucleotides confirming enzyme binding to cAMP, but not to cGMP, in our cell models. cAMP binding to PDE8A/B was displaced upon cell treatment with PDE5i, revealing that sildenafil, tadalafil and vardenafil have similar effectiveness in live cells, in vitro. The cross-interaction between PDE5i and PDE8A/B supports the gonadotropin-enhanced intracellular cAMP increase, occurring together with cGMP increase, as well as steroid synthesis. Indeed, we found that Leydig cell treatment by PDE5i increases progesterone and testosterone production triggered by gonadotropins. We demonstrated that PDE5i may interact with the cAMP-specific PDE8A and PDE8B, possibly inducing intracellular cAMP and sex steroid hormone increase. These findings support clinical data suggesting that PDE5i might increase testosterone levels in men.

Vardenafil Activity in Lung Fibrosis and In Vitro Synergy with Nintedanib.

Idiopathic pulmonary fibrosis (IPF) remains an intractably fatal disorder, despite the recent advent of anti-fibrotic medication. Successful treatment of IPF, like many chronic diseases, may benefit from the concurrent use of multiple agents that exhibit synergistic benefit. In this light, phosphodiesterase type 5 inhibitors (PDE5-Is), have been studied in IPF primarily for their established pulmonary vascular effects. However, recent data suggest certain PDE5-Is, particularly vardenafil, may also reduce transforming growth factor beta 1 (TGF-ß1) activation and extracellular matrix (ECM) accumulation, making them a potential target for therapy for IPF. We evaluated fibroblast TGF-ß1-driven extracellular matrix (ECM) generation and signaling as well as epithelial mesenchymal transformation (EMT) with pretreatment using the PDE5-I vardenafil. In addition, combinations of vardenafil and nintedanib were evaluated for synergistic suppression of EMC using a fibronectin enzyme-linked immunosorbent assay (ELISA). Finally, the effects of vardenafil on fibrosis were investigated in a bleomycin mouse model. Our findings demonstrate that vardenafil suppresses ECM generation alone and also exhibits significant synergistic suppression of ECM in combination with nintedanib in vitro. Interestingly, vardenafil was shown to improve fibrosis markers and increase survival in bleomycin-treated mice. Vardenafil may represent a potential treatment for IPF alone or in combination with nintedanib. However, additional studies will be required.

Erectile dysfunction drugs altered the activities of antioxidant enzymes, oxidative stress and the protein expressions of some cytochrome P450 isozymes involved in the steroidogenesis of steroid hormones.

OBJECTIVES: Infertility is a global health problem with about 15 percent of couples involved. About half of the cases of infertility are related to male-related factors. A major cause of infertility in men is oxidative stress, which refers to an imbalance between levels of reactive oxygen species (ROS) and antioxidants. Erectile dysfunction drugs (EDD), known as phosphodiesterase inhibitors (PDEIs), have been used for the treatment of ED. It has been shown that oxidative stress plays an important role in the progression of erectile dysfunction. Oxidative stress can be alleviated or decreased by non-antioxidants and antioxidant enzymes. The present study was undertaken to determine if these compounds could have a role in the incidence of infertility, especially after long-term use. Therefore, the present study aims to investigate the effect of EDD on the activities of antioxidant enzymes, free radical levels as well as the protein expression of different cytochrome P450 isozymes involved in the steroidogenesis of different hormones. In addition, the activity of both 17ß-hydroxysteroid dehydrogenase and 17-ketosteroid reductase were assayed. The architectures of both livers and testes cells were investigated under the influence of EDD. METHODS: A daily dose of Sildenafil (1.48 mg/kg), Tadalafil (0.285 mg/kg) and Vardenafil (0.285 mg/kg) were administered orally to male rabbits for 12 week. Western immunoblotting, ELISA, spectrophotometric and histopathological techniques were used in this study. RESULTS: The present study showed that Sildenafil, Vardenafil, and Tadalafil treatments significantly decreased the levels of glutathione and free radicals in both livers and testes of rabbits. Also, Vardenafil and Sildenafil induced the activity of superoxide dismutase and catalase whereas, glutathione S-transferase, glutathione reductase, and glutathione peroxidase activities inhibited in livers of rabbits. The protein expression of cytochrome P450 isozymes (CYP 11A1, 21A2, and 19C) which are involved in the steroidogenesis was markedly changed in both livers and testes of rabbits after their treatments for 12 weeks. After the treatment of rabbits with these medication, the protein expression of CYP11A1 was slightly down-regulated in both livers and testes except Sildenafil up-regulated such protein expression. In addition, the protein expressions of CYP11A1 and CYP 19C in both livers and testes were down-regulated after treatment of rabbits with Sildenafil, Vardenafil, and Tadalafil for 12 weeks. Also, these drugs inhibited the activity of both 17ß-hydroxysteroid dehydrogenase and 17-ketosteroid reductase in testes of rabbits. Moreover, Sildenafil, Vardenafil, and Tadalafil-treated rabbits showed a decrease in spermatocytes and the number of sperms in the testes. CONCLUSIONS: It is concluded that ED drugs induced the activities of both SOD and catalase which consequently decreased MDA level. Decrement in MDA levels and oxidative stress could therefore sustain the erection for a long period of time. On the other hand, it is not advised to use these drugs for a long-term since the protein expressions of CYP isozymes involved in steroidogenesis as well as the numbers of spermatocytes in testes were decreased.

Vardenafil increases intracellular accumulation of the most prevalent mutant cystic fibrosis transmembrane conductance regulator (CTFR) in human bronchial epithelial cells.

Cystic fibrosis (CF) is a genetic disease characterized by progressive lung and chronic digestive manifestations. We have shown that therapeutic doses of vardenafil, a phosphodiesterase type 5 (PDE5) inhibitor, corrects CF Transmembrane conductance Regulator (CFTR)-dependent chloride transport in respiratory and intestinal tissues of F508del homozygous mice. Here, we studied the effect of vardenafil on CFTR in 16HBE14o- and CFBE41o- cell lines. First, the expression levels of PDE5 mRNA in these cell lines were monitored. The two cell lines were exposed to different drugs (dimethyl sulfoxide, 8-Br-cGMP, forskolin or vardenafil). The cAMP and cGMP intracellular concentrations were measured. Finally, we localised the CFTR by immunolabelling. PDE5 was similarly expressed in both wild-type and in CF cells. A fast and transient rise in cGMP intracellular contents followed treatment with vardenafil, confirming its PDE5 inhibitory effect. We showed that vardenafil promoted both the early steps of the cellular processing and the trafficking of F508del without fully addressing the protein to the plasma membrane. The effect was not reproduced by the brominated cGMP analogue and it was not prevented by the combination of a protein kinase G (PKG) inhibitor and vardenafil. These findings support the view that vardenafil partially rescues F508del through cGMP/PKG-independent mechanisms.

Efficacy of vardenafil in human nasal mucosa.

OBJECTIVE: Levitra, a phosphodiesterase-5 (PDE5) inhibitor, is the trade name of vardenafil. It is applied to treatment of erectile dysfunction. PDE5 inhibitors dilate the penile blood vessels and cause prolonged erections. However, the effects of Levitra on human nasal mucosa are not yet fully explored. MATERIALS AND METHODS: We examined the effectiveness of Levitra on human nasal mucosa directly in vitro by testing: 1) effect on human nasal mucosa resting tension; 2) effect on contraction caused by 10-6 M methoxamine as a sympathetic mimetic; 3) effect of the drugs on electrically induced human nasal mucosa contractions. RESULTS: The results showed that addition of methoxamine to the incubation medium caused the nasal mucosa to contract in a dose-dependent manner. Addition of Levitra at doses of 10-4 M elicited a significant relaxation response to 10-6 M methoxamine-induced mucosa strip contraction. Levitra could not inhibit electrical field stimulation-induced spike contraction and had a minimal effect on the basal tension of nasal mucosa as the concentration increased. CONCLUSION: This study indicated that high concentrations of Levitra had a significant spasmolytic effect by antagonizing α-adrenoceptors. Moreover, nasal obstruction might not be relieved in patients suffering from erectile dysfunction and stuffy noses who were concomitant using α-adrenergic agonist and Levitra.

Repurposing erectile dysfunction drugs tadalafil and vardenafil to increase bone mass.

We report that two widely-used drugs for erectile dysfunction, tadalafil and vardenafil, trigger bone gain in mice through a combination of anabolic and antiresorptive actions on the skeleton. Both drugs were found to enhance osteoblastic bone formation in vivo using a unique gene footprint and to inhibit osteoclast formation. The target enzyme, phosphodiesterase 5A (PDE5A), was found to be expressed in mouse and human bone as well as in specific brain regions, namely the locus coeruleus, raphe pallidus, and paraventricular nucleus of the hypothalamus. Localization of PDE5A in sympathetic neurons was confirmed by coimmunolabeling with dopamine ß-hydroxylase, as well as by retrograde bone-brain tracing using a sympathetic nerve-specific pseudorabies virus, PRV152. Both drugs elicited an antianabolic sympathetic imprint in osteoblasts, but with net bone gain. Unlike in humans, in whom vardenafil is more potent than tadalafil, the relative potencies were reversed with respect to their osteoprotective actions in mice. Structural modeling revealed a higher binding energy of tadalafil to mouse PDE5A compared with vardenafil, due to steric clashes of vardenafil with a single methionine residue at position 806 in mouse PDE5A. Collectively, our findings suggest that a balance between peripheral and central actions of PDE5A inhibitors on bone formation together with their antiresorptive actions specify the osteoprotective action of PDE5A blockade.

Identification and experimental confirmation of novel cGMP efflux inhibitors by virtual ligand screening of vardenafil-analogues.

BACKGROUND: Clinical studies have reported overexpression of PDE5 and elevation of intracellular cyclic GMP in various types of cancer cells. ABCC5 transports cGMP out of the cells with high affinity. PDE5 inhibitors prevent both cellular metabolism and cGMP efflux by inhibiting ABCC5 as well as PDE5. Increasing intracellular cGMP is hypothesized to promote apoptosis and growth restriction in tumor cells and also has potential for clinical use in treatment of cardiovascular disease and erectile dysfunction. Vardenafil is a potent inhibitor of both PDE5 and ABCC5-mediated cGMP cellular efflux. Nineteen novel vardenafil analogs that have been predicted as potent inhibitors by VLS were chosen for tests of their ability to inhibit ATP- dependent transport of cGMP by measuring the accumulation of cyclic GMP in inside-out vesicles. AIM: In this study, we investigated the ability of nineteen new compounds to inhibit ABCC5- mediated cGMP transport. We also determined the Ki values of the six most potent compounds. METHODS: Preparation of human erythrocyte inside out vesicles and transport assay. RESULTS: Ki values for six of nineteen compounds that showed more than 50 % inhibition of cGMP transport in the screening test were determined and ranged from 1.1 to 23.1 µM. One compound was significantly more potent than the positive control, sildenafil. CONCLUSION: Our findings show that computational screening correctly identified vardenafil-analogues that potently inhibit cGMP efflux-pumps from cytosol and could have substantial clinical potential in treatment of patients with diverse disorders.

Skeletal restoration by phosphodiesterase 5 inhibitors in osteopenic mice: Evidence of osteoanabolic and osteoangiogenic effects of the drugs.

Phosphodiesterases (PDEs) hydrolyze cyclic nucleotides and thereby regulate diverse cellular functions. The reports on the skeletal effects of PDE inhibitors are conflicting. Here, we screened 17 clinically used non-xanthine PDE inhibitors (selective and non-selective) using mouse calvarial osteoblasts (MCO) where the readout was osteoblast differentiation. From this screen, we identified sildenafil and vardenafil (both PDE5 inhibitors) having the least osteogenic EC50. Both drugs significantly increased vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) expressions in MCO and the nitric oxide synthase inhibitor L-NAME completely blocked VEGF expression induced by these drugs. Sunitinib, a tyrosine receptor kinase inhibitor that also blocks VEGFR2 blocked sildenafil-/vardenafil-induced osteoblast differentiation. At half of their human equivalent doses, i.e. 6.0 mg/kg sildenafil and 2.5 mg/kg vardenafil, the maximum bone marrow level of sildenafil was 32% and vardenafil was 21% of their blood levels. At these doses, both drugs enhanced bone regeneration at the femur osteotomy site and completely restored bone mass, microarchitecture, and strength in OVX mice. Furthermore, both drugs increased surface referent bone formation and serum bone formation marker (P1NP) without affecting the resorption marker (CTX-1). Both drugs increased the expression of VEGF and VEGFR2 in bones and osteoblasts and increased skeletal vascularity. Sunitinib completely blocked the bone restorative and vascular effects of sildenafil and vardenafil in OVX mice. Taken together, our study suggested that sildenafil and vardenafil at half of their adult human doses completely reversed osteopenia in OVX mice by an osteogenic mechanism that was associated with enhanced skeletal vascularity.

The Phosphodiesterase-5 Inhibitor Vardenafil Improves the Activation of BMP Signaling in Response to Hydrogen Peroxide.

PURPOSE: The pleiotropic roles of phosphodiesterase-5 inhibitors (PDE5is) in cardiovascular diseases have attracted attention. The effect of vardenafil (a PDE5i) is partly mediated through reduced oxidative stress, but it is unclear whether vardenafil protects against hydrogen peroxide (H2O2)-induced endothelial cell injury, and the molecular mechanisms that are involved remain unknown. We determined the protective role of vardenafil on H2O2-induced endothelial cell injury in cultured human umbilical vein endothelial cells (HUVECs). METHODS AND RESULTS: Vardenafil decreased the number of TUNEL-positive cells, increased the Bcl2/Bax ratio, and ameliorated the numbers of BrdU-positive cells in H2O2-treated HUVECs. The bone morphogenetic protein receptor (BMPR)/p-Smad/MSX2 pathway was enhanced in response to H2O2, and vardenafil treatment could normalize this pathway. To determine whether the BMP pathway is involved, we blocked the BMP pathway using dorsomorphin, which abolished the protective effects of vardenafil. We found that vardenafil improved the H2O2-induced downregulation of BMP-binding endothelial regulator protein (BMPER), which possibly intersects with the BMP pathway in the regulation of endothelial cell injury in response to oxidative stress. CONCLUSIONS: We demonstrated for the first time that exogenous H2O2 activates BMPR expression and promotes Smad1/5/8 phosphorylation. Additionally, vardenafil can attenuate H2O2-induced endothelial cell injury in HUVECs. Vardenafil decreases apoptosis through an improved Bcl-2/Bax ratio and increases cell proliferation. Vardenafil protects against endothelial cell injury through ameliorating the intracellular oxidative stress level and BMPER expression. The protective role of vardenafil on H2O2-induced endothelial cell injury is mediated through BMPR/p-Smad/MSX2 in HUVECs.

Phosphodiesterase inhibitors roflumilast and vardenafil prevent sleep deprivation-induced deficits in spatial pattern separation.

Sleep deprivation (SD) is known to impair hippocampus-dependent memory processes, in part by stimulating the phosphodiesterase (PDE) activity. In the present study, we assessed in mice whether SD also affects spatial pattern separation, a cognitive process that specifically requires the dentate gyrus (DG) subregion of the hippocampus. Adult male mice were trained in an object pattern separation (OPS) task in the middle of the light phase and then tested 24 hr thereafter. In total, we conducted three studies using the OPS task. In the first study, we validated the occurrence of pattern separation and tested the effects of SD. We found that 6 hr of SD during the first half of the light phase directly preceding the test trial impaired the spatial pattern separation performance. As a next step, we assessed in two consecutive studies whether the observed SD-induced performance deficits could be prevented by the systemic application of two different PDE inhibitors that are approved for human use. Both the PDE4 inhibitor roflumilast and PDE5 inhibitor vardenafil successfully prevented SD-induced deficits in spatial pattern separation. As a result, these PDE inhibitors have clinical potential for the prevention of memory deficits associated with loss of sleep.

Low-dose vardenafil potentiates the protective effect of (-)-epigallocatechin gallate on cardiomyocytes.

The major polyphenol (-)-epigallocatechin gallate (EGCG) of green tea shows well-known health benefits such as potential anti-cancer, anti-oxidation and ameliorating cardiovascular disease. This work aims to improve the bioactivity of EGCG on H9C2 cardiomyocytes by combination regimen of vardenafil and EGCG. The proliferative rates were significantly improved by 18.74%, 10.77% and 29.17% after 48 h with EGCG, vardenafil, and the combination of EGCG and low-dose vardenafil treatments, respectively. The treatments also increased the expression of the nitric oxide synthase (eNOS), and acutely stimulate production of vasodilators nitric oxide (NO) from 17.33µmol/L to 19.75, 20.87 and 24.47µmol/L in H9C2 cells. We further demonstrated that vardenafil also remarkably promoted EGCG to counteract H2O2-induced apoptotic damage in H9C2 by strengthening antioxidant defense systems and suppressing myocardial apoptosis. These results suggest that EGCG and low-dose vardenafil in combination may be a promising regimen to help prevent cardiovascular diseases.

Early administration of phosphodiesterase 5 inhibitors after induction of diabetes in a rat model may prevent erectile dysfunction.

BACKGROUND: The possible role of phosphodiesterase 5 inhibitors (PDE5Is) in prevention of negative effect of diabetes mellitus (DM) on erectile function is not well settled. OBJECTIVES: To investigate the effect of early administration of vardenafil on erectile function, cavernosal structure, and genes expression in a rat model of DM. MATERIALS AND METHODS: This experimental study was carried out at Suez Canal University's research laboratory. This study was conducted on a total of 60 adult male Albino Wistar rats, aged 60-80 days and weighing an average of 200 g. Rats were equally divided into six groups of 10 rats each: Group I (sham); Group II (DM with no treatment); Groups III, IV, V, and VI received vardenafil started at day 1, week 4, week 8, and week 12 after induction of DM, respectively. Functional study assessment of all groups was performed before euthanization, and then tissues were harvested for histopathological, ultrastructural, and molecular examinations. RESULTS: There was a significant difference of intracavernosal pressure between early (94 ± 2.18) and late (40.5 ± 1.94) treatment groups (p = 0.011). Histopathological and ultrastructural changes of DM with no treatment and late treatment groups showed distorted cavernous architecture and extensive fibrosis. There was significant difference of smooth muscle to collagen ratio between early and late treatment groups (p = 0.035). There was significant upregulation of nNOS(p = 0.021) and iNOS (p = 0.047) in early vs. late treatment group. The difference was insignificant in eNOS (p = 0.386) or TGF-ß1(p = 0.149). DISCUSSION AND CONCLUSION: Early treated rats with vardenafil had preserved erection and normal cavernosal structure, ultrastructure and gene expression of iNOS, nNOS, eNOS, and TGF-ß1. Quantification of gene expression would improve our knowledge regarding cytokines expression and molecular background of DM-associated ED. Clinical application of this result may encourage early administration of PDE5I to prevent deleterious effects of DM on erectile function in newly diagnosed DM patients with probable uncontrolled blood glucose.

Pro-cognitive effect of upregulating cyclic guanosine monophosphate signalling during memory acquisition or early consolidation is mediated by increased AMPA receptor trafficking.

BACKGROUND: Episodic memory consists of different mnemonic phases, including acquisition and early and late consolidation. Each of these phases is characterised by distinct molecular processes. Although both cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) are implicated in the acquisition phase, early consolidation only depends on cGMP, whereas late consolidation is mediated by cAMP. Accordingly, the cGMP-selective phosphodiesterase 5 (PDE5) inhibitor vardenafil or the cAMP-selective PDE4 inhibitor rolipram can improve memory acquisition or consolidation when applied during their respective time windows. AIMS: Considering the important role of glutamatergic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR) during normal memory function, we aimed to investigate whether the differential actions of these PDE inhibitors are mediated through AMPAR dynamics. METHODS: For biochemical analysis, mice were treated with either vardenafil or rolipram and sacrificed shortly after injection. For the behavioural studies, mice received either of the inhibitors during the different mnemonic phases, while their spatial memory was tested using the object location task, and they were sacrificed 24 hours later. RESULTS: Administration of either vardenafil or rolipram causes rapid changes in AMPARs. Moreover, treatment with vardenafil during the acquisition or early consolidation of spatial memory resulted in increased surface levels of AMPARs which were still augmented 24 hours after learning. Membrane levels of AMPARs were not affected anymore 24 hours after learning when rolipram was administrated at either the acquisition or late consolidation phase. CONCLUSIONS: These results suggest that dissociative molecular mechanisms could mediate the pro-cognitive function of different classes of PDE inhibitors, and in the case of vardenafil, this phenomenon could be explained by changes in AMPAR dynamics.

Comparison of the protective effects of sildenafil, vardenafil and tadalafil treatments in ischemia-reperfusion injury in rat ovary.

OBJECTIVES: The aim of this study was to compare the effects of sildenafil, vardenafil and tadalafil in treatment for ischemia/reperfusion injury which is created experimentally in rat ovaries. MATERIAL AND METHODS: For this study, 30 female Wistar albino rats were used, and the rats were separated randomly intofive groups consisting of six rats each: normal, torsion-detorsion, torsion-detorsion + sildenafil 1.4 mg/kg, torsion-detorsion+ vardenafil 1.7 mg/kg and torsion-detorsion + tadalafil 5.0 mg/kg. The agents were given intraperitoneally 30 minutesbefore detorsion. An ovarian torsion procedure was implemented in all other groups for 3 hours with the exception of thenormal group. Then, a detorsion procedure was implemented to the groups for 3 hours. RESULTS: The sildenafil and vardenafil treatments showed protective effect by preventing significant increase in inflammationparameters. (p = 0.058, 0.138). The tadalafil treatment was only protective for cellular degeneration (p = 0.140). Thevardenafil treatment was protective for edema (p = 0.238), vascular congestion (p = 0.111), inflammation (p = 0.138) andcellular degeneration (p = 0.532). Sildenafil, vardenafil and tadalafil inhibited the increase of atretic follicle. AMH levels werestatistically different between torsion and detorsion and vardenafil group (p = 0.004, 0.004), whereas tadalafil and sildenafilgroups were similar to normal group (p = 0.108, 0.108). CONCLUSIONS: PDE inhibitors were found to be effective in reducing ovarian ischemia/reperfusion injury. Sildenafil andtadalafil seem to be more effective than the vardenafil in protecting the ovarian reserve.