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)

Hypercholesterolemia was induced in New Zealand white rabbits by feeding them a 0.5% cholesterol-enriched rabbit chow for 2 wk. Half of the cholesterol-fed rabbits were given lovastatin, a potent inhibitor of hydroxymethylglutaryl-coenzyme A reductase (HMG-CoA reductase), the rate limiting enzyme in cholesterol biosynthesis, and the other half were given its vehicle (i.e., DMSO). At the end of 2 wk, the rabbits underwent experimental myocardial ischemia or a sham ischemia procedure. Ischemic animals fed the cholesterol-enriched diet for 2 wk experienced much greater cardiac damage than ischemic rabbits fed the control diet, despite the absence of any atherosclerosis. Lovastatin was shown to protect the ischemic rabbit myocardium by three different indices of ischemic damage: (a) maintenance of creatine kinase (CK) activity in the ischemic myocardium; (b) reduced loss of free amino-nitrogen containing compounds from the ischemic myocardium; and (c) blunting the rise of plasma CK activity. These effects were not due to differences in myocardial oxygen demand between the groups. Arteries isolated from animals fed the cholesterol-enriched diet developed defects in endothelium-dependent relaxation in both large vessels as well as coronary resistance vessels. Acute hypercholesterolemia increases the severity of myocardial ischemia while at the same time impairing endothelium-dependent relaxation. These deleterious changes can be significantly attenuated by treatment with lovastatin.
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PMID:Cardiovascular effects of acute hypercholesterolemia in rabbits. Reversal with lovastatin treatment. 291 50

We examined the effects of pravastatin and simvastatin, HMG-CoA reductase inhibitors, on stunned myocardium in vivo. Pravastatin and simvastatin were given orally 2 mg/kg for 3 weeks. After 3 weeks of administration, pentobarbital-anesthetized dogs were subjected to 15-min left anterior descending (LAD) coronary artery occlusion followed by 2-h reperfusion. Myocardial segment function was determined by sonomicrometry. The tissue energy and carbohydrate metabolites were determined in the 2-h-reperfused hearts. Administration of pravastatin and simvastatin for 3 weeks decreased serum cholesterol level and blood pressure (BP). Simvastatin resulted in a worsening of segment shortening in the reperfused myocardium as compared with control and pravastatin groups. The level of ATP in the simvastatin group was significantly lower as compared with that in the control group. The other metabolite levels were not significantly altered by either pravastatin or simvastatin. These results suggest that simvastatin enhances stunning of the myocardium in association with ATP reduction after reperfusion subsequent to ischemia.
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PMID:Influences of pravastatin and simvastatin, HMG-CoA reductase inhibitors, on myocardial stunning in dogs. 750 4

The aim of the present study was to examine the effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors on mitochondrial respiration in ischemic rat hearts, and to compare the effects between water-soluble pravastatin and lipid-soluble simvastatin. Either vehicle (0.5% carboxymethyl cellulose), pravastatin (2 or 4 mg/kg per day), or simvastatin (1 or 2 mg/kg per day) was orally administered for 3 weeks. Ischemia was induced by ligating the aorta for 60 min in anesthetized open chest rats under artificial respiration. The hearts were removed, mitochondria were isolated, and the respiration was determined by polarography using glutamate and succinate as substrates. When succinate was used as a substrate, the ADP-stimulated respiration (QO3) and ATP production per unit oxygen (ADP/O ratio) were decreased by ischemia. The decreases in QO3 and ADP/O ratio in the pravastatin- and simvastatin-treated groups appeared to be more prominent than those in the vehicle-treated group. This was especially true in the simvastatin-treated group. The ADP-limited respiration (QO4) with succinate in the vehicle-treated heart was slightly increased by ischemia, while that in the pravastatin- or simvastatin-treated hearts was decreased. In conclusion, HMG-CoA reductase inhibitors may result in worsening of myocardial mitochondrial respiration during ischemia.
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PMID:Effects of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors on mitochondrial respiration in ischemic rat hearts. 779 66

Effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, pravastatin and simvastatin, on mitochondrial respiration in ischemic rat liver were examined. Either vehicle, pravastatin (2 or 4 mg/kg per day), or simvastatin (1 or 2 mg/kg per day) was orally administered for 3 weeks. Liver ischemia was induced by cessation of the systemic circulation for 60 min. Liver mitochondria were isolated and the respiration was determined by polarography using glutamate and succinate as substrates. In the vehicle-treated group, ischemia drcreased ZO3, respiratory control index (RCI: QO3/QO4), and ADP/O ratio. Pretreatments with pravastatin and simvastatin enhanced the decreases in QO3 measured with either glutamate or succinate, and in ADP/O ratio measured with succinate. Because of decreasing QO4, HMG-CoA reductase inhibitors did not modify the changes in RCI due to ischemia. There were no significant differences in respiratory indices between pravastatin- and simvastatin-treated groups. In conclusion, HMG-CoA reductase inhibitors may enhance respiratory impairment of liver mitochondria under pathophysiological conditions, such as ischemia.
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PMID:Influence of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors on mitochondrial respiration in rat liver during ischemia. 780 87

Coronary artery disease mortality can be reduced by aggressive lipid lowering. The reduction in cardiovascular events observed in the recent major lipid lowering trials is dramatically better than that seen in the classic studies of medically or surgically managed CAD from the 1970s. One postulated mechanism for this improvement is restoration of normal endothelial function through cholesterol lowering. By restoring endothelial dependent vasodilation, cardiovascular events and ischemia can be reduced. PTCA has variable effects on endothelial function. Lipid lowering is beneficial in combination with invasive CAD interventions. The appropriate management of coronary artery disease should consider the advance in medically managed outcomes provided by HMG CoA reductase inhibitors (statins).
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PMID:Medical management of coronary artery disease revisited: the endothelial factor. 931 36

HMG-CoA reductase inhibitors are potent cholesterol-lowering drugs. Recent clinical trials and meta-analyses show a 30% stroke reduction after treatment with HMG-CoA reductase inhibitors. Subgroup analyses and experimental findings support the notion that HMG-CoA reductase inhibitors improve endothelial function directly by mechanism(s) independent of cholesterol-lowering. They reduce inflammatory, proliferative and thrombogenic processes in atherosclerotic plaques and improve endothelial dysfunction. Recent findings demonstrate an enhanced production of endothelium-derived nitric oxide (NO) by HMG-CoA reductase inhibitors. Endothelial NO is an important vasodilator and plays a beneficial role in cerebral ischemic injury. Prophylactic treatment with HMG-CoA reductase inhibitors in mice selectively upregulates endothelial NO synthase expression and activity, increases cerebral blood flow at resting state and during ischemia, and reduces cerebral infarct size after experimental stroke. These findings provide a novel mechanism for the prophylactic treatment of ischemia-induced cerebral injury under non-hypercholesterolemic conditions.
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PMID:[HMG-CoA reductase inhibitor and risk of stroke]. 975 26

Effects of pravastatin, simvastatin, atorvastatin, fluvastatin and cerivastatin on myocardial contractile dysfunction during reperfusion after brief ischemia were examined in dogs. Pretreatment of the dog with lipophilic HMG-CoA reductase inhibitors for 3 weeks, simvastatin (2 mg/kg/day), atorvastatin (2 mg/kg/day), fluvastatin (4 mg/kg/day), and cerivastatin (40 micrograms/kg/day) worsened recovery of myocardial contraction during reperfusion after brief ischemia in association with reduced myocardial ATP level. A hydrophilic HMG-CoA reductase inhibitor, pravastatin (2 and 4 mg/kg/day), did not affect the recovery of myocardial contractile function and ATP level during reperfusion following ischemia. The lipophilic inhibitors may enter the myocardial cell, inhibit ubiquinone biosynthesis, and depress ATP generation in mitochondria, leading to worsening of the myocardial stunning after reperfusion subsequent to ischemia.
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PMID:[Are all HMG-CoA reductase inhibitors protective against ischemic heart disease?]. 1062 71

Pretreatment of dogs with simvastatin, a lipophilic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, increases myocardial contractile dysfunction during reperfusion after ischemia (stunning), with reduction of tissue adenosine triphosphate (ATP). This was thought to be a consequence of prevention of ubiquinone biosynthesis by the lipophilic inhibitor in the myocardial cell. We examined whether other lipophilic HMG-CoA reductase inhibitors also influence myocardial stunning in dogs. Vehicle, atorvastatin (2 mg/ kg/day), fluvastatin (4 mg/kg/day), or cerivastatin (40 microg/kg/ day) was orally administered for 3 weeks. Hydrophilic pravastatin (4 mg/kg/day) also was given. After 3 weeks, pentobarbital-anesthetized dogs were subjected to 15-min left anterior descending coronary artery occlusion followed by 2-h reperfusion. Myocardial segment function was determined by sonomicrometry. Tissue levels of ATP were determined in 2-h reperfused hearts. All inhibitors significantly decreased serum cholesterol level. The three lipophilic inhibitors resulted in a worsening of segment function in the reperfused myocardium, as compared with the vehicle group. The levels of ATP in the atorvastatin, fluvastatin, and cerivastatin groups were significantly lower than that in the vehicle group. These results confirm that lipophilic HMG-CoA reductase inhibitors enhance myocardial stunning in association with ATP reduction after ischemia and reperfusion.
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PMID:Lipophilic HMG-CoA reductase inhibitors increase myocardial stunning in dogs. 1067 58

Endothelial progenitor cells (EPCs) have been isolated from circulating mononuclear cells in peripheral blood and shown to incorporate into foci of neovascularization, consistent with postnatal vasculogenesis. These circulating EPCs are derived from bone marrow and are mobilized endogenously in response to tissue ischemia or exogenously by cytokine stimulation. We show here, using a chemotaxis assay of bone marrow mononuclear cells in vitro and EPC culture assay of peripheral blood from simvastatin-treated animals in vivo, that the HMG-CoA reductase inhibitor, simvastatin, augments the circulating population of EPCs. Direct evidence that this increased pool of circulating EPCs originates from bone marrow and may enhance neovascularization was demonstrated in simvastatin-treated mice transplanted with bone marrow from transgenic donors expressing beta-galactosidase transcriptionally regulated by the endothelial cell-specific Tie-2 promoter. The role of Akt signaling in mediating effects of statin on EPCs is suggested by the observation that simvastatin rapidly activates Akt protein kinase in EPCs, enhancing proliferative and migratory activities and cell survival. Furthermore, dominant negative Akt overexpression leads to functional blocking of EPC bioactivity. These findings establish that augmented mobilization of bone marrow-derived EPCs through stimulation of the Akt signaling pathway constitutes a novel function for HMG-CoA reductase inhibitors.
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PMID:HMG-CoA reductase inhibitor mobilizes bone marrow--derived endothelial progenitor cells. 1148 28

Although 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors can protect the myocardium against ischemic injury, the mechanisms of their effect have not yet been characterized at the cellular level. Therefore, we investigated the role of cardiac ATP-sensitive K+ (K(ATP)) channels induced by the HMG-CoA reductase inhibitor known as pravastatin on the myocardial metabolism during ischemia by phosphorus 31-nuclear magnetic resonance (31P-NMR) in isolated rabbit hearts. Forty-five min of continuous normothermic global ischemia was carried out. Pravastatin with or without the K(ATP) channel blocker glibenclamide or the nitric oxide synthase inhibitor L-NAME was administered beginning 60 min prior to the global ischemia. Twenty-eight hearts were divided into 4 experimental groups consisting of 7 hearts each: the control group, the P group consisting of pravastatin treatment, the P+G group consisting of pravastatin treatment with glibenclamide, and the P+L group consisting of pravastatin treatment with L-NAME. During ischemia, the decreases in adenosine triphosphate (ATP) and intracellular pH (pHi) were significantly inhibited in the P group in comparison with Control group (at end of ischemia, respectively; both p<0.01), as was the increase in inorganic phosphate (Pi) (at end of ischemia, p<0.01). However, the decreases in ATP and pHi and the increase in Pi were not inhibited in the P+G group during ischemia. The P+L group also showed no inhibition of the aforementioned parameters during the same period. These results suggest that pravastatin has a significant beneficial effect for improving the myocardial energy metabolism, which is provided by K(ATP) channels and nitric oxide (NO), during myocardial ischemia. The cardioprotection of HMG-CoA reductase inhibitor may be caused by the K(ATP) channels that are mediated by the NO.
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PMID:Role of cardiac ATP-sensitive K+ channels induced by HMG CoA reductase inhibitor in ischemic rabbit hearts. 1167 53


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