Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cardiologists are seeing increasing numbers of patients with erectile dysfunction (ED), which frequently coexists with cardiovascular disease. The pharmacologic profile of the new class of phosphodiesterase (PDE) inhibitors-specifically PDE5 inhibitors-and their potential effects on hemodynamic variables have therefore become significant factors in therapeutic decision making. Most of the published data linking PDE5 inhibitor effects and cardiovascular disease relate to sildenafil, although >or=2 new agents are in various stages of development and clinical trials. Sildenafil and other PDE5 inhibitors act on vascular smooth muscle, predominantly in the corpus cavernosum. PDE5 is not found in cardiomyocytes, and no effect of PDE5 inhibition on cardiac contractility has been demonstrated. On the basis of a safety database comprising thousands of men with ED, sildenafil has demonstrated minimal adverse effects in men with stable ischemia, hypertension, and/or severe coronary artery disease. Sildenafil has modest effects on hemodynamic variables and has been shown to increase coronary artery flow reserve. Alone or combined with >or=1 antihypertensive medication, sildenafil did not increase the incidence of adverse events or hypotensive episodes. Sildenafil-associated decreases in systolic and diastolic blood pressure, the result of its vasodilator activity, have been modest. Sildenafil has decreased both elevated pulmonary vascular resistance and elevated pulmonary artery pressures in patients with pulmonary vascular disease. Beneficial changes in hemodynamics have been observed with the use of sildenafil in patients with congestive heart failure with underlying ischemic and other dilated cardiomyopathies. No association between sildenafil and increased cardiovascular morbidity or mortality has emerged in analyses of clinical trial data.
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PMID:Sildenafil in patients with cardiovascular disease. 1460 21

The novel type of neurotransmitter/neuromodulator nitric oxide (NO) is linked to activation of the N-methyl-D-aspartate (NMDA) class of glutamate receptors and has been shown to modify transmitter release in the brain. The inhibitory neuromodulator adenosine has been thought to act as an endogenous neuroprotectant against cerebral ischemia and neuronal damage. The effects of NO-generating compounds on the release of preloaded [3H]adenosine from hippocampal slices from developing (7-day-old) and adult (3-month-old) mice were investigated, using a superfusion system, under normal conditions and in vitro ischemia. The release of adenosine was markedly potentiated at both ages by the NO-producing compounds S-nitroso-N-acetylpenicillamine, sodium nitroprusside, and hydroxylamine. The evoked releases were reduced by the NO synthase inhibitors nitroarginine and 7-nitroindazole at both ages. They were also reduced by the inhibitor of soluble guanylyl cyclase 1H-(1,2,4-oxadiazolo(4,3a)quinoxalin-1-one (ODQ) in adults, indicating that the NO/cGMP pathway is involved in this release. Release of adenosine was also evoked when the cGMP levels were increased by superfusing slices with the phosphodiesterase inhibitor zaprinast. The markedly enhanced adenosine release under ischemic conditions was further potentiated by the ionotropic glutamate receptor agonists and NO-generating compounds, whereas zaprinast and ODQ had no effect, rendering unlikely the involvement of cGMP in the ischemic release. Moreover, NO was able to provoke substantial release of adenosine in the presence of NMDA under both normal and ischemic conditions, which could significantly add to the neuroprotective potential of this neuromodulator in both adult and developing hippocampus.
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PMID:Involvement of nitric oxide in adenosine release in the developing and adult mouse hippocampus. 1499 81

Erectile dysfunction (ED) is often a marker for serious underlying cardiovascular disease (CVD), and cardiologists are increasingly involved in the care of men with ED. It is important to ask specifically about ED when evaluating men with CVD, since they may be embarrassed to volunteer this information. During the clinical workup, it is also important to check for contributing factors to ED such as diabetes, depression, stress, alcohol abuse, and cardiovascular risk factors. Patients should be advised that many treatment options are available for ED, including the phosphodiesterase type 5 (PDE5) inhibitors. The PDE5 inhibitors are safe and effective in most patients with CVD, including those taking multiple antihypertensive drugs. Furthermore, they have no deleterious effect on exercise capacity, heart rate, or extent of exercise-induced ischemia. In the future, the PDE5 inhibitors may have a role in reducing pulmonary hypertension in persons with primary pulmonary arterial hypertension (PAH) or congestive heart failure. The one major precaution for men taking PDE5 inhibitors is to avoid concomitant administration of therapeutic and recreational nitrate preparations. Patients with chest pain suggestive of a heart attack need to inform emergency room (ER) personnel if they are taking a PDE5 inhibitor. Similarly, before giving nitrates, ER personnel need to ask patients if they have used PDE5 inhibitors. Nitrates should not be given for at least 24 h after a patient uses sildenafil or vardenafil and at least 48 h after a patient uses tadalafil.
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PMID:Role of the cardiologist: clinical aspects of managing erectile dysfunction. 1511 89

The relaxing effect of the phosphodiesterase type 5 (PDE5) inhibitors on vascular smooth muscle has attracted much attention, especially in persons with cardiovascular disease. The results of early studies showed that sildenafil slightly reduces systolic and diastolic blood pressures and has no effect on heart rate, while being safe and well tolerated. Studies also indicate that sildenafil does not contribute to the development of myocardial infarction or ischemia. Similar benign effects on hemodynamics and cardiac events have also been demonstrated for tadalafil and vardenafil. None of the PDE5 inhibitors adversely affects total exercise time or time to ischemia during exercise testing in men with stable angina. It is key to avoid concomitant administration of nitrates with any of the PDE5 inhibitors, because this combination can cause increased vasodilation and a subsequent drop in blood pressure. Sildenafil has an alpha-blocker precaution; tadalafil is contraindicated with alpha blockers except for 0.4 mg tamsulosin; vardenafil is contraindicated with alpha blockers.
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PMID:Novel phosphodiesterase type 5 inhibitors: assessing hemodynamic effects and safety parameters. 1511 92

The effects of selective inhibitors of phosphodiesterase type IV (PDE4) on ischemia-reperfusion-induced gastric injuries were investigated in rats. Gastric ischemia was induced by applying a small clamp to the celiac artery, and reoxygenation was performed by removal of the clamp. Ischemia-reperfusion produced gastric hemorrhagic injuries and increased the content of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) and myeloperoxidase (MPO) activity in gastric mucosa. Rolipram (0.03-0.3 mg/kg, s.c.) and Ro-20-1724 (0.3-3 mg/kg, s.c.) prevented the development of gastric injury in a dose-dependent manner, and it also inhibited the increase in mucosal TNF-alpha content and MPO activity induced by ischemia-reperfusion. The anti-ulcer drug irsogladine (1-10 mg/kg, p.o.), which is known to possess a PDE4 inhibitory action, also inhibited the gastric injury produced by ischemia-reperfusion, as well as the increase in TNF-alpha levels and MPO activity. It is concluded that the ability of PDE4 inhibitors to inhibit cytokine TNF-alpha synthesis and the infiltration of polymorphonuclear leukocytes underlies their gastroprotective effects in ischemia-reperfusion-induced gastric injury. Our experiments suggest that drugs that inhibit PDE4 isoenzyme, such as the anti-ulcer drug irsogladine, may be a useful adjunct therapy for the treatment of the gastric damage that follows ischemia-reperfusion.
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PMID:Phosphodiesterase type IV inhibitors prevent ischemia-reperfusion-induced gastric injury in rats. 1527 7

Transplantation of human neural stem cells (NSCs) is a promising potential therapy for neurologic dysfunctions after the hyperacute stage of stroke in humans, but large amounts of human NSCs must be expanded in long-term culture for such therapy. To determine their possible therapeutic potential for human stroke, human fetal neural stem/progenitor cells (NSPCs) (i.e., neurosphere-forming cells) were isolated originally from forebrain tissues of one human fetus, and expanded in long-term neurosphere culture (exceeding 24 weeks), then xenografted into the lesioned areas in the brains of Mongolian gerbils 4 days after focal ischemia. Sensorimotor and cognitive functions were evaluated during the 4 weeks after transplantation. The total infarction volume in the NSPC-grafted animals was significantly lower than that in controls. Approximately 8% of the grafted NSPCs survived, mainly in areas of selective neuronal death, and were costained with antibodies against neuronal nuclei antibody (NeuN), microtubule associated protein (MAP-2), glial fibrillary acidic protein (GFAP), and anti-2'3' cyclic nucleotide 3'-phosphodiesterase (CNPase). Synaptic structures between NSPCs-derived neurons and host neurons were observed. Furthermore, gradual improvement of neurologic functions was observed clearly in the NSPC-grafted animals, compared to that in controls. Human NSPCs, even from long-term culture, remarkably improved neurologic functions after focal ischemia in the Mongolian gerbil, and maintained their abilities to migrate around the infarction, differentiate into mature neurons, and form synapses with host neuronal circuits. These results indicate that in vitro-expanded human neurosphere cells are a potential source for transplantable material for treatment of stroke.
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PMID:Human neural stem/progenitor cells, expanded in long-term neurosphere culture, promote functional recovery after focal ischemia in Mongolian gerbils. 1537 9

Infants undergoing surgery for congenital heart disease are at risk for myocardial ischemia during cardiopulmonary bypass, circulatory arrest, or low-flow states. The purpose of this study was to demonstrate the effects of sildenafil, a selective phosphodiesterase-5 (PDE-5) inhibitor on myocardial functional improvement and infarct size reduction during ischemia/reperfusion injury in infant rabbits. Infant rabbits (aged 8 wk) were treated with sildenafil citrate (0.7 mg/kg i.v.) or normal saline 30 min before sustained ischemia for 30 min and reperfusion for 3 h. Transesophageal echocardiography (TEE) was used to assess left ventricular cardiac output (LVCO) and aortic velocity time integral (VTI). After ischemia/reperfusion, risk area was demarcated by Evan's blue dye and infarct size determined by computer morphometry of triphenyltetrazolium chloride-stained sections. The sildenafil-treated group had preservation and elevation in LVCO (143% of baseline, p < 0.05) and an elevated aortic VTI (145% of baseline, p < 0.05) after 30 min of ischemia compared with the control group LVCO (72% of baseline, p < 0.05) and aortic VTI (73% of baseline, p < 0.05). This is a statistically significant increase in LVCO and aortic VTI in the sildenafil group compared with controls (n = 6/group, p < 0.05). The sildenafil-treated group had significant reduction in infarct size (15.5 +/- 1.2 versus 33 +/- 2.3 in the saline group, % risk area, mean +/- SEM, n = 10-15/group, p < 0.05). For the first time, we have shown that sildenafil citrate promotes myocardial protection in infant rabbits as evidenced by postischemic preservation and elevation in LVCO and aortic VTI and reduction in infarct size.
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PMID:Sildenafil citrate (viagra) induces cardioprotective effects after ischemia/reperfusion injury in infant rabbits. 1553 35

We investigated the effect of sildenafil in protection against necrosis or apoptosis in cardiomyocytes. Adult mouse ventricular myocytes were treated with sildenafil (1 or 10 microM) for 1 h before 40 min of simulated ischemia (SI). Necrosis was determined by trypan blue exclusion and lactate dehydrogenase release following SI alone or plus 1 or 18 h of reoxygenation (RO). Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated nick end labeling assay and mitochondrial membrane potential measured using a fluorescent probe 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolyl-carbocyanine iodide (JC-1). Sildenafil reduced necrosis as indicated by decrease in trypan blue-positive myocytes and leakage of lactate dehydrogenase compared with untreated cells after either SI or SI-RO. The number of terminal deoxynucleotidyl transferase-mediated nick end labeling-positive myocytes or loss of JC-1 fluorescence following SI and 18 h of RO was attenuated in the sildenafil-treated group with concomitant inhibition of caspase 3 activity. An early increase in Bcl-2 to Bax ratio with sildenafil treatment was also observed in myocytes after SI-RO. The increase of Bcl-2 expression by sildenafil was inhibited by nitric-oxide synthase (NOS) inhibitor, L-nitro-amino-methyl-ester. The drug also enhanced mRNA and protein content of inducible NOS (iNOS) and endothelial NOS (eNOS) in the myocytes. Sildenafil-induced protection against necrosis and apoptosis was absent in the myocytes derived from iNOS knock-out mice and was attenuated in eNOS knock-out myocytes. The up-regulation of Bcl-2 expression by sildenafil was also absent in iNOS-deficient myocytes. Reverse transcription-PCR, Western blots, and immunohistochemical assay confirmed the expression of phosphodiesterase-5 in mouse cardiomyocytes. These data provide strong evidence for a direct protective effect of sildenafil against necrosis and apoptosis through NO signaling pathway. The results may have possible therapeutic potential in preventing myocyte cell death following ischemia/reperfusion.
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PMID:Phosphodiesterase-5 inhibitor sildenafil preconditions adult cardiac myocytes against necrosis and apoptosis. Essential role of nitric oxide signaling. 1566 44

Recent studies suggest that erectile dysfunction (ED) may be an early marker of endothelial dysfunction and coronary artery disease (CAD). Conversely, patients with CAD commonly have ED. The phosphodiesterase 5 (PDE5) inhibitors are very effective for the treatment of ED in patients with CAD. Numerous studies show that this class of drugs is in general safe in patients with stable CAD and these agents do not exacerbate ischemia in men with CAD undergoing exercise stress testing. Analysis of placebo-controlled trials did not show an increase in cardiovascular events among men receiving PDE5 inhibitors, and post-marketing surveillance studies with sildenafil did not observe an increase in cardiovascular events compared to expected age-matched rates. Organic nitrates remain a contraindication for PDE5 inhibitors and alpha blockers have precautions/contraindications depending upon specific drugs. The Princeton Consensus Guidelines (soon to be updated) suggest a logical approach to the patient with CAD seeking therapy for sexual dysfunction.
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PMID:Erectile dysfunction in patients with coronary artery disease. 1572 74

Increasing clinical and experimental evidence implicate cerebral hypoperfusion during increased ageing and points to chronic cerebrovascular ischemia as a vital component of the neuropathological progression of dementia. In vivo cerebral perfusion animal models can greatly contribute to the evaluation of drugs and to the screening of drug interactions. This study describes a baboon Papio ursinus model under anaesthesia, for in vivo cerebral blood flow (CBF) determinations, using Single Photon Emission Computed Tomography (SPECT) following the split-dose method with 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO). Perfusion studies with acetazolamide as intervention clearly showed that the non-human primate model under aneasthesia is sufficiently sensitive to serve in the evaluation of other cerebrovasoactive drugs for induced perfusion changes with significant increases of the R-value (+40%) for comparative measurement when compared to the control value (2.53+/-0.15 vs. 1.79+/-0.13). These findings stimulated investigations of several drugs, i.e. pentifylline (phosphodiesterase inhibitor); nimodipine (calcium channel blocker); sumatriptan (serotonin receptor agonist) and nicotinic acid (vasodilator) for CBF effects. Increases in the cerebral perfusion in some cases more than +30% for nimodipine (2.51+/-0.14 vs. 1.79+/-0.13), acetazolamide and +29% for the combination of pentifylline and nicotinic acid (2.31+/-0.19 vs. 1.79+/-0.13) were observed. Drug interaction studies revealed an attenuation of increased CBF due to nimodipine, with sumatriptan (-25%) and acetazolamide (+22%) in combination with nimodipine. Drug interactions with clinical implications may result during simultaneous use of cerebrovasoactive drugs in managing patients with cerebrovascular disorders. This study further showed that the CBF non-human primate model under anaesthesia is useful for the investigation of vasoactive drugs acting via various pharmacological modes of action.
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PMID:Non-human primate SPECT model for determining cerebral perfusion effects of cerebrovasoactive drugs acting via multiple modes of pharmacological action. 1576 Jun 48


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