sildenafil-citrate and Constriction--Pathologic

Persistent pulmonary hypertension of the newborn (PPHN) is the most common neonatal form and mostly reversible after a few days with improvement of the underlying pulmonary condition. When pulmonary hypertension (PH) persists despite adequate treatment, the severity of parenchymal lung disease should be assessed by chest CT. Pulmonary vein stenosis may need to be ruled out by cardiac catheterisation and lung biopsy, and genetic workup is necessary when alveolar capillary dysplasia is suspected. In PPHN, optimisation of the cardiopulmonary situation including surfactant therapy should aim for preductal SpO2between 91% and 95% and severe cases without post-tricuspid-unrestrictive shunt may receive prostaglandin E1 to maintain ductal patency in right heart failure. Inhaled nitric oxide is indicated in mechanically ventilated infants to reduce the need for extracorporal membrane oxygenation (ECMO), and sildenafil can be considered when this therapy is not available. ECMO may be indicated according to the ELSO guidelines. In older preterm infant, where PH is mainly associated with bronchopulmonary dysplasia (BPD) or in term infants with developmental lung anomalies such as congenital diaphragmatic hernia or cardiac anomalies, left ventricular diastolic dysfunction/left atrial hypertension or pulmonary vein stenosis, can add to the complexity of the disease. Here, oral or intravenous sildenafil should be considered for PH treatment in BPD, the latter for critically ill patients. Furthermore, prostanoids, mineralcorticoid receptor antagonists, and diuretics can be beneficial. Infants with proven or suspected PH should receive close follow-up, including preductal/postductal SpO2measurements, echocardiography and laboratory work-up including NT-proBNP, guided by clinical improvement or lack thereof.

Topics: Acute Disease; Administration, Inhalation; Bronchopulmonary Dysplasia; Cardiac Catheterization; Chronic Disease; Consensus; Constriction, Pathologic; Endothelium-Dependent Relaxing Factors; Extracorporeal Membrane Oxygenation; Humans; Hypertension, Pulmonary; Infant; Infant, Newborn; Infant, Premature; Lung Diseases; Nitric Oxide; Persistent Fetal Circulation Syndrome; Phosphodiesterase 5 Inhibitors; Pulmonary Veins; Sildenafil Citrate; Tomography, X-Ray Computed

Oxidative stress and DNA damage have been implicated in the pathogenesis of renovascular hypertension induced by renal artery stenosis in the two-kidney, one-clip (2K1C) Goldblatt model. Considering our previous report indicating that the chronic blockade of phosphodiesterase 5 with sildenafil (Viagra) has marked beneficial effects on oxidative stress and DNA damage, we tested the hypothesis that sildenafil could also protect the stenotic kidneys of 2K1C hypertensive mice against oxidative stress and genotoxicity.. The experiments were performed with C57BL6 mice subjected to renovascular hypertension by left renal artery clipping. Two weeks after clipping, the mice were treated with sildenafil (40 mg/kg/day for 2 weeks, 2K1C-sildenafil group) or the vehicle (2K1C). These mice were compared with control mice not subjected to renal artery clipping (Sham). After hemodynamic measurements, the stenotic kidneys were assessed using flow cytometry to evaluate cell viability and the comet assay to evaluate DNA damage. Measurements of intracellular superoxide anions and hydrogen peroxide levels as well as nitric oxide bioavailability were also obtained.. Sildenafil treatment significantly reduced mean arterial pressure (15%), heart rate (8%), intrarenal angiotensin II (50%) and renal atrophy (36%). In addition, it caused a remarkable decrease of reactive oxygen species production. On the other hand, sildenafil increased nitric oxide levels relative to those in the nontreated 2K1C mice. Sildenafil treatment also significantly reduced the high level of kidney DNA damage that is a characteristic of renovascular hypertensive mice.. Our data reveal that sildenafil has a protective effect on the stenotic kidneys of 2K1C mice, suggesting a new use of phosphodiesterase 5 inhibitors for protection against the DNA damage observed in the hypoperfused kidneys of individuals with renovascular hypertension. Further translational research is necessary to delineate the mechanisms involved in the prevention of renal stenosis in the clinical setting.

Topics: Angiotensin II; Animals; Blood Pressure; Body Weight; Comet Assay; Constriction, Pathologic; DNA Damage; Heart Rate; Hypertension, Renovascular; Kidney; Kidney Function Tests; Mice; Mice, Inbred C57BL; Organ Size; Oxidative Stress; Piperazines; Purines; Reactive Oxygen Species; Renal Artery; Sildenafil Citrate; Sulfones

Selective right pulmonary arteriography and 3-dimensional computed tomography revealed multiple severe stenoses of the peripheral pulmonary artery associated with poststenotic aneurysms in a 65-year-old woman. She was referred to the hospital for evaluation of dry cough, gradually increasing dyspnea and multiple nodular shadows on a chest radiograph. Echocardiography and cardiac catheterization showed severe pulmonary hypertension, though other structural heart diseases or well-characterized congenital syndromes were ruled out. She was diagnosed as isolated peripheral pulmonary artery branch stenosis. Recent advances in CT technology enable a less-invasive assessment of pulmonary artery, and can be useful in the management of pulmonary arterial hypertension.

Topics: Aged; Aneurysm; Arterial Occlusive Diseases; Cardiac Catheterization; Constriction, Pathologic; Cough; Dyspnea; Epoprostenol; Female; Humans; Hypertension, Pulmonary; Imaging, Three-Dimensional; Oxygen Inhalation Therapy; Piperazines; Pulmonary Artery; Purines; Sildenafil Citrate; Sulfones; Tomography, X-Ray Computed; Ultrasonography; Vasodilator Agents; Warfarin

Increased myocardial cGMP, achieved by enhancing cyclase activity or impeding cGMP hydrolysis by phosphodiesterase type-5 (PDE5A), suppresses cellular and whole organ hypertrophy. The efficacy of the latter also requires cyclase stimulation and may depend upon co-activation of maladaptive signaling suppressible by cGMP-stimulated kinase (cGK-1). Thus, PDE5A inhibitors could paradoxically be more effective against higher than lower magnitudes of pressure-overload stress. To test this, mice were subjected to severe or moderate trans-aortic constriction (sTAC, mTAC) for 6 wks +/-co-treatment with oral sildenafil (SIL 200 mg/kg/d). LV mass (LVM) rose 130% after 3-wks sTAC and SIL blunted this by 50%. With mTAC, LVM rose 56% at 3 wks but was unaffected by SIL, whereas a 90% increase in LVM after 6 wks was suppressed by SIL. SIL minimally altered LV function and remodeling with mTAC until later stages that stimulated more hypertrophy and remodeling. SIL stimulated cGK-1 activity similarly at 3 and 6 wks of mTAC. However, pathologic stress signaling (e.g. calcineurin, ERK-MAPkinase) was little activated after 3-wk mTAC, unlike sTAC or later stage mTAC when activity increased and SIL suppressed it. With modest hypertrophy (3-wk mTAC), GSK3beta and Akt phosphorylation were unaltered but SIL enhanced it. However, with more severe hypertrophy (6-wk mTAC and 3-wk sTAC), both kinases were highly phosphorylated and SIL treatment reduced it. Thus, PDE5A-inhibition counters cardiac pressure-overload stress remodeling more effectively at higher than lower magnitude stress, coupled to pathologic signaling activation targetable by cGK-1 stimulation. Such regulation could impact responses of varying disease models to PDE5A inhibitors.

Topics: Animals; Aorta; Constriction, Pathologic; Cyclic GMP-Dependent Protein Kinases; Cyclic Nucleotide Phosphodiesterases, Type 5; Enzyme Activation; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Hypertrophy; Male; Mice; Mice, Inbred C57BL; Phosphodiesterase 5 Inhibitors; Phosphorylation; Piperazines; Pressure; Proto-Oncogene Proteins c-akt; Purines; Signal Transduction; Sildenafil Citrate; Stress, Physiological; Sulfones; Time Factors