sildenafil-citrate and fasudil

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Bosentan; Drug Therapy, Combination; Epoprostenol; Humans; Hypertension, Pulmonary; Mice; Molecular Targeted Therapy; Piperazines; Protein Kinase Inhibitors; Purines; Rats; rho-Associated Kinases; Signal Transduction; Sildenafil Citrate; Sulfonamides; Sulfones; Vascular Resistance

Chronic neonatal pulmonary hypertension frequently culminates in right ventricular (RV) failure and death. In juvenile rats, RV systolic dysfunction secondary to chronic hypoxia is rescued by systemic treatment with a Rho kinase (ROCK) inhibitor. To explore the relationship between ROCK inhibitor-mediated decreases in pulmonary vascular resistance and pressure, RV hypertrophy, and systolic dysfunction, we compared the effects of systemically administered to inhaled (pulmonary-selective) ROCK inhibitor on RV systolic function. Rat pups were exposed to air or hypoxia (13% O2) from Postnatal Days 1 to 21 and received rescue treatment with aerosolized fasudil (200 mM) for 15 minutes three times daily or intraperitoneal Y27632 (15 mg/kg twice daily) from Days 14 to 21. Chronic hypoxia differentially increased RhoA and ROCK activity in the right, but not left, cardiac ventricle. Inhaled ROCK inhibitor normalized pulmonary vascular resistance and caused regression of RV hypertrophy and pulmonary arterial wall remodeling but did not improve RV systolic dysfunction (decreased stroke volume and tricuspid annular plane systolic excursion). Systemic, but not inhaled, ROCK inhibitor normalized up-regulated ROCK and phosphodiesterase 5 activities in the right ventricle. Treatment with sildenafil (100 mg/kg/d intraperitoneally from Days 14 to 21) improved RV systolic function. Collectively, these data indicate that pressure unloading and regressed arterial and cardiac remodeling did not lead to recovery of systolic function while right ventricular ROCK activity remained increased. Right ventricle-specific up-regulation of RhoA/ROCK activity is critical to hypoxia-mediated systolic dysfunction, in part by regulating the activity of phosphodiesterase 5.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Cyclic Nucleotide Phosphodiesterases, Type 5; Heart Ventricles; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Piperazines; Purines; Rats; rho-Associated Kinases; rhoA GTP-Binding Protein; Sildenafil Citrate; Sulfonamides; Vascular Resistance; Ventricular Dysfunction, Right

 Pulmonary hypertension (PH) is a fatal disease characterized by pulmonary artery (PA) remodeling, elevated PA pressure and right ventricular (RV) failure. It has been previously demonstrated that treatment with a Rho-kinase inhibitor, fasudil, ameliorates PH in animal models. Here, whether combination therapy with fasudil and sildenafil further ameliorates PH in rats was examined..  PH was induced in Sprague-Dawley rats by the use of a single subcutaneous monocrotaline (MCT) injection, which caused PA remodeling, elevated RV systolic pressure (RVSP), and RV hypertrophy (RVH). While fasudil and sildenafil monotherapy inhibited the development of MCT-induced PH in the prevention and treatment protocols, their combination therapy further improved RVSP and RVH. Moreover, a histological examination demonstrated significant improvements of PA remodeling in the combination group compared with the monotherapy groups. An echocardiographic examination also revealed significant reduction in RV diameter in the combination group compared with the monotherapy groups. Mechanistic experiments revealed significant inhibition of Rho-kinase activity in PA trunk, lung and RV tissues in the combination group as well as in the monotherapy groups. Finally, the combination therapy markedly improved the long-term survival compared with the monotherapy groups..  These results indicate that the combination therapy with fasudil and sildenafil shows the synergistic effects through the inhibition of Rho-kinase activity for the treatment of PH.  

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Calcium Channel Blockers; Drug Therapy, Combination; Hypertension, Pulmonary; Male; Monocrotaline; Phosphodiesterase 5 Inhibitors; Piperazines; Purines; Rats; Rats, Sprague-Dawley; Sildenafil Citrate; Sulfones

Pulmonary arterial hypertension (PAH) still cannot be cured effectively, hence the search for novel treatments continues. The effects of sildenafil (25 mg/kg body weight) and fasudil (30 mg/kg body weight) given alone or in combination, on normalization of right ventricular pressure (RVP), right ventricle mass, as well as the levels of several biomarkers (HDL-C, BNP, VEGF-A), were assessed in a rat model of monocrotaline (MCT)-induced PAH. MCT (60 mg/kg body weight) induced clear PAH in male Wistar rats. After 21 days, a significant decrease in RVP accompanied by a reduction of right ventricular hypertrophy - a significant decrease in the right ventricle/left ventricle plus septum ratio - as a result of sildenafil or fasudil administration was assessed. The administration of fasudil and sildenafil alone or in combination caused a significant decrease in plasma BNP level as compared to MCT-treated rats. Fasudil alone or with sildenafil, but not sildenafil alone, significantly increased HDL-C level as compared to MCT-treated rats. Fasudil and sildenafil given alone or in combination caused a significant increase in plasma VEGF-A level as compared to rats exposed to MCT.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Cholesterol, HDL; Drug Therapy, Combination; Familial Primary Pulmonary Hypertension; Hemodynamics; Hypertension, Pulmonary; Male; Monocrotaline; Natriuretic Peptide, Brain; Phosphodiesterase 5 Inhibitors; Piperazines; Protein Kinase Inhibitors; Purines; Rats; Rats, Wistar; rho-Associated Kinases; Sildenafil Citrate; Sulfones; Vascular Endothelial Growth Factor A

Pulmonary arterial hypertension (PAH) still cannot be cured, warranting the search for novel treatments. Fasudil (a Rho kinase inhibitor) was compared with bosentan (an endothelin receptor blocker) and sildenafil (a phosphodiesterase 5 inhibitor), with emphasis on right ventricular (RV) function, in a reversal rat model of monocrotaline (MCT)-induced PAH. In addition, the effects of combining bosentan or sildenafil with fasudil were studied. MCT (40 mg·kg body weight(-1)) induced clear PAH in male Wistar rats (n = 9). After 28 days, echocardiography, RV catheterisation and histochemistry showed that cardiac frequency, stroke volume and RV contractility had deteriorated, accompanied by RV dilatation and hypertrophy, and marked pulmonary arterial wall thickening. Mean pulmonary arterial pressure and pulmonary vascular resistance increased significantly compared to healthy rats (n = 9). After 14 days, MCT-treated rats received a 14-day oral treatment with bosentan, sildenafil, fasudil or a combination of fasudil with either bosentan or sildenafil (all n = 9). All treatments preserved cardiac frequency, stroke volume and RV contractility, and reduced pulmonary vascular resistance and RV dilatation. Fasudil lowered RV systolic pressure and mean pulmonary arterial pressure significantly, by reducing pulmonary arterial remodelling, which reduced RV hypertrophy. Combining bosentan or sildenafil with fasudil had no synergistic effect. Fasudil significantly improved PAH, to a greater degree than did bosentan and sildenafil.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Administration, Oral; Animals; Antihypertensive Agents; Blood Pressure; Bosentan; Familial Primary Pulmonary Hypertension; Heart Ventricles; Hemodynamics; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Monocrotaline; Piperazines; Pulmonary Artery; Purines; Rats; Sildenafil Citrate; Sulfonamides; Sulfones; Vasodilator Agents

Inhibition of the type 5 phosphodiesterase and inhibition of Rho kinase are both effective in reducing pulmonary hypertension (PH). Here we investigate whether Rho kinase inhibition is involved in the beneficial effect of the type 5 phosphodiesterase inhibitor sildenafil on PH. Chronic hypoxia-induced PH in rats is associated with an increase in RhoA activity in pulmonary artery that was maximal after 2 days (10.7+/-0.9-fold increase, n=6, P<0.001). The activity of Rho kinase assessed by measuring the level of myosin phosphatase target subunit 1 (MYPT1) phosphorylation was also increased (5.7+/-0.8-fold over control, n=8). Chronic fasudil (30 mg kg(-1) day(-1); 14 days) and sildenafil (25 mg kg(-1) day(-1); 14 days) treatments reduced PH and pulmonary cardiovascular remodelling, and inhibited the MYPT1 phosphorylation in pulmonary artery from hypoxic rats by 82.3+/-3% (n=4) and by 76.6+/-2% (n=4), respectively. The inhibitory effect of sildenafil (10 microM) on MYPT1 phosphorylation was demonstrated by the loss of actin stress fibres in vascular smooth muscle cells. However, in vitro kinase assays indicated that sildenafil had no direct inhibitory action on Rho kinase activity. Sildenafil treatment induced increased RhoA phosphorylation and association to its cytosolic inhibitory protein, guanine dissociation inhibitor (GDI) in pulmonary artery.We propose that sildenafil inhibits RhoA/Rho kinase-dependent functions in pulmonary artery through enhanced RhoA phosphorylation and cytosolic sequestration by GDI. The inhibition of intracellular events downstream of RhoA thus participates in the beneficial effect of sildenafil on PH.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Actins; Animals; Carrier Proteins; Chronic Disease; Cytoskeleton; Guanine Nucleotide Dissociation Inhibitors; Hypertension, Pulmonary; Hypoxia; Male; Phosphodiesterase Inhibitors; Phosphoprotein Phosphatases; Phosphorylation; Piperazines; Protein Phosphatase 1; Purines; Rats; Rats, Wistar; rhoA GTP-Binding Protein; Sildenafil Citrate; Sulfones