sildenafil-citrate and Atherosclerosis

High plasma cholesterol levels are able to trigger several pathophysiological events, including inflammation, cell damage and especially oxidative stress. Previously, studies have shown that sildenafil exhibited antioxidant effects in several experimental models. Here we evaluate the role of sildenafil in liver redox equilibrium of apolipoprotein E knockout (apoE-KO) mice.. ApoE-KO mice were divided in two groups: one group received the PDE5 inhibitor sildenafil (40 mg/kg/day) for 3 weeks (apoE-KO + Sil) and was compared to a second group of apoE-KO mice, which received only the vehicle (water) for 3 weeks (apoE-KO). Control group (C57 mice) received only a standard chow diet. At the age of 18 weeks, mice livers were collected for the measurement of intracellular ROS levels and apoptotic cells by flow cytometry analysis, and mitochondria isolation for proteomic analysis.. Compared to the control group, liver cells from apoE-KO presented some typical redox imbalance features: higher levels of intracellular ROS (global oxidative stress ˜60%, superoxide anion ˜82%, and peroxynitrite/hydroxyl radical ˜53%), higher amounts of apoptotic cells (up to ˜19%) and higher mitochondrial intensity of catalase (+339%) and transferrin spots (+914%). After treatment with sildenafil, apoE-KO presented ROS levels and the number of apoptotic cells similar to those observed in C57. In addition, when compared to apoE-KO, apoE-KO + Sil showed lower spots volumes of catalase (-23%) and transferrin (-71%) and up-regulation of urate oxidase (+94%).. The treatment with sildenafil is able to induce beneficial changes in liver mitochondrial protein dynamics, which restores the redox homeostasis contributing to a potential hepatoprotection.

Topics: Animals; Antioxidants; Apolipoproteins E; Atherosclerosis; Catalase; Inflammation; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Knockout, ApoE; Mitochondria; Mitochondrial Proteins; Oxidative Stress; Proteomics; Reactive Oxygen Species; Sildenafil Citrate; Superoxides; Triglycerides

Sildenafil, a phosphodiesterase type 5 (PDE5) inhibitor, has endothelium protective and angiogenic effects.. To test if sildenafil improves tissue perfusion and neovascularization and downregulates proinflammatory molecules following limb ischemia.. 30 ApoE-/- male mice, bred with cholesterol rich diet for 4 weeks, were anesthetized and underwent unilateral hind-limb ischemia with ligation of the left femoral artery. Mice were randomized in 2 groups: sildenafil (1 mg/Kg for 7 days intraperitoneally, i.p.) or normal saline (0.4 ml for 7 days, i.p.). Bilateral hind-limb perfusion was estimated by laser Doppler imaging after surgery on days 0, 7 and 28.. Sildenafil significantly reduced at day 28 compared with day 0 levels of soluble intracellular adhesion molecule-1(sICAM-1) [2.24(1.81-2.41) vs. 1.29(0.87-1.45) ng/ml, p=0,01], soluble E-selectin (sE-Selectin) [5.52 (3.67-6.14) vs 1.71 (1.42-2.86) ng/ml, p=0.02] and tissue plasminogen activator inhibitor- 1 (tPAI-1) [0.13(0.07-0.21) vs 0.08 (0.04-0.10) ng/ml, p=0.01] while normal saline had no effect on the levels of sICAM-1, sE-Selectin and tPAI-1. Treatment with sildenafil was associated with increased perfusion in the ischemic limb compared with controls.. Sildenafil exerts significant beneficial effects on tissue perfusion and inflammatory status after limb ischemia, a finding implying neovascularization and potential vascular protective properties of sildenafil.

Topics: Angiogenesis Inducing Agents; Animals; Anti-Inflammatory Agents; Atherosclerosis; Blood Flow Velocity; Disease Models, Animal; E-Selectin; Hindlimb; Inflammation; Inflammation Mediators; Intercellular Adhesion Molecule-1; Ischemia; Male; Mice, Knockout, ApoE; Muscle, Skeletal; Neovascularization, Physiologic; Plasminogen Activator Inhibitor 1; Regional Blood Flow; Sildenafil Citrate; Time Factors

The pharmacological inhibitor of phosphodiesterase 5 (PDE5), sildenafil, is a promising candidate for antioxidant therapy that can result in cardiovascular protection. In addition to its known effects on the cardiovascular system, hypercholesterolemia leads to increased oxidative stress and DNA damage in the bone marrow, which is a non-classical target organ of atherosclerosis. In the present study, we evaluate oxidative stress and assess the effect of genomic instability on cell cycle kinetics in atherosclerotic animals and determine if sildenafil reverses these detrimental effects in bone marrow cells.. Experiments were performed in male wild-type (WT) and apolipoprotein E knockout mice (apoE(-/-)) (9 weeks of age). apoE(-/-) mice were randomly distributed into the following 2 groups: sildenafil-treated (40 mg/kg/day for 3 weeks, n = 8) and vehicle-treated (n = 8), by oral gavage. After treatment, bone marrow cells were isolated to assess the production of superoxide anions and hydrogen peroxide, determine cell cycle kinetics and evaluate the presence of micronucleated cells.. Sildenafil treatment reduced the cytoplasmic levels of superoxide anion (~95% decrease, p < 0.05) and decreased hydrogen peroxide (~30% decrease, p < 0.05). Moreover, we observed protective effects on the DNA of bone marrow cells, including normal cell cycling, decreased DNA fragmentation and a diminished frequency of micronucleated cells.. Our data reveal that the excessive production of ROS in atherosclerotic mice overcome the DNA repair pathways in bone marrow cells. The novelty of the present study is that the administration of sildenafil reduced ROS to baseline levels and, consequently, reverted the DNA damage and its outcomes in bone marrow cells.

Topics: Animals; Apolipoproteins E; Atherosclerosis; Bone Marrow Cells; Cell Cycle; Cell Survival; Cholesterol; Genomic Instability; Male; Mice, Inbred C57BL; Mice, Mutant Strains; Micronucleus Tests; Oxidative Stress; Protective Agents; Reactive Oxygen Species; Sildenafil Citrate; Triglycerides

Sildenafil ameliorates aortic relaxations in apolipoprotein E knockout (apoE) mice. Now, we tested the hypothesis that endothelial dysfunction (ED) in this model is characterized by contractile hyperresponsiveness to phenylephrine (PE) and that this abnormality may be repaired using sildenafil. The aortic rings were evaluated in apoE mice treated with sildenafil (apoE-sil, 40 mg/kg/day) and compared with apoE and wild-type (WT) mice administered with vehicle (veh). The apoE-veh mice exhibited an imbalance of nitric oxide and reactive oxygen species (NO/ROS) levels and an increased maximum response (Rmax, 20%) and sensitivity (7%) to PE, which were not modified by endothelial removal. Under the prostanoids blockade, vasocontraction was decreased more in apoE-veh (-37%) than in WT (-27%) and apoE-sil (-30%) mice. NADPH-oxidase blockade abolished the enhanced contractile responsiveness in apoE-veh (-33%), without effects in WT and apoE-sil groups. The atherosclerotic lesions and the imbalance of NO/ROS were reduced (40%) in apoE-sil mice. In conclusion, ED in apoE mice was characterized by decreased NO-bioavailability and contractile hyperresponsiveness, due to thromboxane and oxidative stress, and was normalized by sildenafil. The beneficial effects of this phosphodiesterase-5 inhibitor on ED and lipid deposition provide new insights for its use as adjuvant in the treatment of atherosclerosis.

Topics: Animals; Apolipoproteins E; Atherosclerosis; Dose-Response Relationship, Drug; Elastic Modulus; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Oxidative Stress; Phosphodiesterase 5 Inhibitors; Reactive Oxygen Species; Sildenafil Citrate; Treatment Outcome; Vascular Stiffness; Vasoconstriction; Vasodilator Agents

It is well known that enhanced production of reactive oxygen species (ROS) leads to oxidative stress observed in atherosclerosis and that ROS can also cause damage in cellular macromolecules, including DNA. Considering previous report that sildenafil, an inhibitor of phosphodiesterase 5 (PDE5), has antioxidant effects, in the present study we evaluated the effect of this drug on genotoxicity of blood mononuclear cells (MNC) and liver cells from atherosclerotic apolipoprotein E knockout mice (apoE(-/-)).. ROS production in MNC was evaluated by flow cytometry with the fluorescent dye dihydroethidium (DHE), a method that has been used to quantify the production of superoxide anion, and DNA damage was evaluated in both MNC and liver cells using the alkaline comet assay. Sildenafil-administered apoE(-/-) mice were compared with strain-matched mice administered with vehicle and with C57BL/6 wild-type (WT) mice.. MNC from apoE(-/-) vehicle exhibited a 2-fold increase in production of superoxide anion in comparison with WT. In contrast, sildenafil-administered apoE(-/-) mice showed superoxide anion levels similar to those observed in WT mice. Similarly, MNC and liver cells from apoE(-/-) vehicle mice showed a 4-fold and 2-fold augmented DNA fragmentation compared with WT, respectively, and sildenafil-administered apoE(-/-) mice exhibited minimal DNA damage in those cells similar to WT mice.. ApoE(-/-) mice chronically administered with sildenafil exhibited reduced levels of superoxide anion in MNC and less DNA fragmentation in MNC and liver cells, which are biomarkers of genotoxicity. Therefore, sildenafil may offer a new perspective to the use of PDE5 inhibitors to protect against DNA damage, in cells involved in the inflammatory and dyslipidemic processes that accompany atherosclerosis.

Topics: Animals; Apolipoproteins E; Atherosclerosis; Comet Assay; Disease Models, Animal; DNA Fragmentation; Leukocytes, Mononuclear; Lipoproteins; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Oxidative Stress; Phosphodiesterase 5 Inhibitors; Piperazines; Purines; Sildenafil Citrate; Sulfones; Superoxides; Triglycerides

To evaluate whether the response to sildenafil administration in patients with arterial erectile dysfunction (ED) was related to their peak systolic velocity (PSV), peripheral atherosclerosis, cardiovascular risk factors (RF) and/or comorbidities at low cardiovascular risk.. We enrolled 97 patients with 1-2 RF and comorbidities, combined with arterial ED alone (group A, n = 27), ED plus atherosclerotic carotid artery (group B, n = 23), ED plus lower limb artery abnormalities (group C, n = 25), and ED plus carotid and lower limb artery abnormalities (group D, n = 22). Sildenafil efficacy (100 mg twice a week for 12 weeks) was also examined in patients with =or>3 RF, peripheral atherosclerosis and no cardiovascular comorbidities (group E, n = 20).. Median PSV was 24.1, 21.0, 19.3, 14.5 and 17.5 cm/s in groups A, B, C, D and E, respectively. Sildenafil response was higher in group A patients (77.8%), intermediate in groups B and C (65.2% and 56%) and lowest in groups D (45.4%) and E (50%), and the response in latter two groups was significantly lower than in the other three groups. In addition, sildenafil response was negatively influenced by: =or>3 RF, peripheral atherosclerosis and no systemic comorbidity, or presence of 1-2 RF associated with extended atherosclerosis and comorbidities. The number of comorbidities was positively related to atherosclerosis localization or extension (25, 35, 38 and 47 in groups A, B, C and D, respectively).. Low sildenafil efficacy in patients with arterial ED was associated with extended atherosclerosis. These patients should undergo extensive ultrasonography and a full cardiovascular examination.

Topics: Aged; Arterial Occlusive Diseases; Atherosclerosis; Cardiovascular Diseases; Erectile Dysfunction; Humans; Lower Extremity; Male; Middle Aged; Physical Examination; Piperazines; Purines; Regional Blood Flow; Retrospective Studies; Risk Factors; Sildenafil Citrate; Sulfones; Treatment Outcome; Vasodilator Agents

Topics: 3',5'-Cyclic-GMP Phosphodiesterases; Atherosclerosis; Carbolines; Erectile Dysfunction; Humans; Imidazoles; Male; Optic Neuropathy, Ischemic; Phosphodiesterase Inhibitors; Piperazines; Purines; Risk Factors; Sildenafil Citrate; Sulfones; Tadalafil; Triazines; Vardenafil Dihydrochloride; Vision Disorders