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

The effect of amyloid beta (Abeta), the major constituent of the Alzheimer's (AD) brain on lipid metabolism was investigated in cultured nerve cells and in a fetal rat brain model. Differentiated (NGF) and undifferentiated PC12 cells or primary cerebral cell cultures were incubated with [14C]acetate in the absence or presence of Abeta1-40. Incorporation of label into lipid species was determined after lipid extraction and TLC separation. Phosphatidylcholine (PC) and phosphatidylserine (PS) synthesis was increased by Abeta1-40, in a dose dependent manner, an effect which was more pronounced in differentiated PC12 cells. A significant proportion of radioactivity (5-6%) was released into the medium with a radioactivity distribution similar to that of the cellular lipids. Cholesterol and PC were the highest labeled medium lipids. Increasing Abeta1-40 concentration up to 0.1 microg/ml in cerebral cells but not in PC12 cells, caused a relative increase (1.5 fold) in release of PS, while that of PE decreased. Stimulation of PS release may possibly be associated with apoptotic cell death. Abeta1-40 peptide (5 microg) was administered intraperitoneally into rat fetuses (18 days gestation) along with [14C]acetate (2 microCi/fetus). After 24 h, the maternal-fetal blood supply was occluded for 20 min (ischemia) followed by 15 min reperfusion. Fetuses were killed and liver and brain tissue subjected to lipid extraction and radioactivity determination after TLC. Abeta1-40 peptide increased synthesis of different classes of lipids up to 20-40% in brain tissue compared to controls. Labeling of liver lipids was decreased by Abeta1-40 by 20-30%. A general decrease in synthesis of lipids was observed after ischemia/reperfusion. Our data suggest that Abeta1-40 peptide regulates normal lipid biosynthesis but under ischemia it compromises it. The latter finding may confirm the oxidative stress etiology in AD and suggests that Abeta1-40 modulation of lipid metabolism may have Alzheimer's pathological relevance, particularly at high peptide concentrations.
 ...
PMID:Alzheimer's Abeta1-40 peptide modulates lipid synthesis in neuronal cultures and intact rat fetal brain under normoxic and oxidative stress conditions. 1090 27

The success of cholesterol treatment in reducing cardiovascular events has suggested addition of a cholesterol paradigm to previous clinical models of stenosis and occlusion in coronary artery disease. Risk factors for coronary artery disease now serve as guidelines for treatment goals for low-density lipoprotein cholesterol reduction. Oxidation of low-density lipoprotein cholesterol within the vessel wall initiates a variety of deleterious mechanisms contributing to atherosclerosis. Hepatic hydroxymethylglutaryl-coenzyme A reductase inhibitors or statin drugs exert a primary action on hepatic cholesterol metabolism, as well as influences on vascular reactivity, thrombus formation, inflammation, ischemia, and plaque stabilization. Trials with statin drugs have reported reduction of cardiovascular events in men and women without clinical evidence of coronary artery disease. Several trials have demonstrated angiographic stabilization with cholesterol lowering and a greater reduction in cardiovascular events, revascularization procedures, and strokes. Recent studies suggest benefits in lowering triglycerides and raising high-density lipoprotein cholesterol with drugs. A clinical approach with available cholesterol-lowering drugs is presented based on National Cholesterol Education Program guidelines and follow-up time tables. Thus, cholesterol therapy offers the opportunity to treat atherosclerotic vascular disease before, during, and after ischemic events.
 ...
PMID:Cardiovascular basis for cholesterol therapy. 1117 84

The results of the "MIRACL" trial ("Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering") were presented at the recent annual meeting of the American Heart Association in New Orleans last November 2000. This study demonstrates that atorvastatin, at a daily dose of 80 mg starting within the first 24 to 96 hours after an acute coronary event (unstable angina or non-Q-wave acute myocardial infarction) and maintained for 4 months, improves the cardiovascular prognosis by decreasing the combined risk of death (any cause), nonfatal myocardial infarction, resuscitated cardiac arrest and worsening angina with new objective evidence of ischemia requiring urgent hospitalization (-16% versus placebo, p < 0.05).
 ...
PMID:[Meeting report. "MIRACL" study of "Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering"]. 1120 94

The purpose of this study was to modify the amount of 22:4 n-6, 22:5 n-6 and 20:5 n-3 in cardiac phospholipids and to evaluate the influence of these changes on the functioning of working rat hearts and mitochondrial energy metabolism under normoxic conditions and during postischemic reperfusion. The animals were fed one of these four diets: (i) 10% sunflower seed oil (SSO); (ii) 10% SSO + 1% cholesterol; (iii) 5% fish oil (FO, EPAX 3000TG, Pronova) + 5% SSO; (iv) 5% FO + 5% SSO + 1% cholesterol. Feeding n-3 PUFA decreased n-6 PUFA and increased n-3 PUFA in plasma lipids. In the phospholipids of cardiac mitochondria, this dietary modification also induced a decrease in the n-6/n-3 PUFA ratio. Cholesterol feeding induced marked hepatic steatosis (HS) characterized by the whitish appearance of the liver. It also brought about marked changes in the fatty acid composition of plasma and mitochondrial phospholipids. These changes, characterized by the impairment of deltaS- and delta6-desaturases, were more obvious in the SSO-fed rats, probably because of the presence of the precursor of the n-6 family (linoleate) in the diet whereas the FO diet contained large amounts of eicosapentaenoic and docosahexaenoic acids. In the mitochondrial phospholipids of SSO-fed rats, the (22:4 n-6 + 22:5 n-6) to 18:2 n-6 ratio was decreased by HS, without modification of the proportion of 20:4 n-6. In the mitochondrial phospholipids of FO-fed rats, the amount of 20:5 n-3 tended to be higher (+56%). Cardiac functioning was modulated by the diets. Myocardial coronary flow was enhanced by HS in the SSO-fed rats, whereas it was decreased in the FO-fed animals. The rate constant k012 representing the activity of the adenylate kinase varied in the opposite direction, suggesting that decreased ADP concentrations could cause oxygen wasting through the opening of the permeability transition pore. The recovery of the pump function tended to be increased by n-3 PUFA feeding (+22%) and HS (+45%). However, the release of ascorbyl free radical during reperfusion was not significantly modified by the diets. Conversely, energy production was increased by ischemia/reperfusion in the SSO group, whereas it was not modified in the FO group. This supports greater ischemia/reperfusion-induced calcium accumulation in the SSO groups than in the FO groups. HS did not modify the mitochondrial energy metabolism during ischemia/reperfusion. Taken together, these data suggest that HS- and n-3 PUFA-induced decrease in 22:4 and 22:5 n-6 and increase in 20:5 n-3 favor the recovery of mechanical activity during post-ischemic reperfusion.
 ...
PMID:Effects of dietary polyunsaturated fatty acids and hepatic steatosis on the functioning of isolated working rat heart under normoxic conditions and during post-ischemic reperfusion. 1169 87

Cholesterol emboli are being increasingly recognized as an important cause of renal dysfunction in an aging US population. Irregularly shaped atheroemboli typically cause partial obstruction of small renal vessels resulting in ischemia. A vasculitis-like picture often evolves with an inflammatory reaction and giant cell formation. Cholesterol emboli may be temporally related to vascular manipulation, anticoagulant, or thrombolytic drug use. Spontaneous cases have been reported. Patients with cholesterol emboli may present with a spectrum of acute renal failure varying from mild and asymptomatic to life-threatening disease. The differential diagnosis includes radiocontrast nephropathy, endocarditis with left-sided emboli, vasculitis, and thrombotic emboli. The physical examination findings suggestive of cholesterol emboli include extrarenal emboli and livedo reticularis. The urinalysis is typically unremarkable. Some patients have hematuria and/or non-nephrotic proteinuria. Serology and hematology results may suggest an inflammatory-like picture with elevated erythrocyte sedimentation rate, hypocomplementemia, eosinophilia, and eosinophiluria. In the setting of a clear precipitating factor and suggestive physical findings, cholesterol emboli can be established purely on clinical grounds. Demonstration of cholesterol crystals by biopsy of the kidney, skin (if lesion present), or muscle is diagnostic in unexplained cases. The kidney is the organ most frequently involved in this order. Therapy is supportive with particular emphasis on management of hypertension and hypercholesterolemia.
 ...
PMID:Atheroembolic Renal Disease. 1186 88

The Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) study was the first trial to assess whether statins might be of clinical benefit in those with recently unstable coronary disease. MIRACL found that high-dose atorvastatin was safe and reduced the incidence of the composite endpoint, death, non-fatal myocardial infarction, resuscitated sudden cardiac death or emergent rehospitalization for recurrent ischemia at 16 weeks when compared with placebo. Despite a number of important study limitations, MIRACL's findings and the prior observation that inpatient initiation of lipid-lowering therapy is associated with higher rates of subsequent utilization, suggest that it is prudent to begin statin therapy when patients present with an acute coronary syndrome.
 ...
PMID:The Myocardial Ischemia Reduction with Acute Cholesterol Lowering trial: MIRACuLous or not, it's time to change current practice. 1198 77

Statins may act rapidly to reverse abnormalities of the arterial wall that may predispose to recurrent ischemic events after acute coronary syndromes. Such abnormalities are endothelial dysfunction, a local inflammatory response. and an exaggerated thrombogenic tendency. In one study almost 20,000 patients with first myocardial infarction were studied with regard to statin treatment (28%) or not. Baseline characteristics were adjusted using multivariate regression analysis including propensity analysis. One year mortality was 3.7/5.0% in statin/not statin groups, respectively, P = 0.001, relative risk 0.75. In another study of more than 20,000 patients, 18% were prescribed statin after an acute coronary syndrome and followed for six months. Propensity analysis was performed in this study as well. Deaths in statin/not statin groups were 1.7/3.5%, P<0.0001, relative risk 0.48. In the Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL), a double-blind randomized, placebo-controlled intervention study, 3086 patient with acute non-Q-wave coronary syndromes were allocated immediately in hospital to receive atorvastatin 80 mg daily or placebo for four months. No lower limit for plasma LDL cholesterol was used. Primary endpoint was time to first occurrence of death, non-fatal myocardial infarction, cardiac arrest, and worsening angina with objective evidence of ischemia. This was significantly reduced compared to the placebo group by 2.4% (14.8 versus 17.2%, relative risk 0.84, P= 0.048). Atorvastatin also reduced significantly fatal or non-fatal strokes. Possible mechanisms behind these acute beneficial effects are discussed. The studies highlight the importance of treatment with a statin in the early management of acute coronary syndromes and the need to incorporate this therapeutic strategy in national guidelines and treatment recommendations.
 ...
PMID:Early initiation of treatment with statins in acute coronary syndromes. 1201 32

A senile patient developed fatal intestinal necrosis right after uneventful cardiovascular operation using usual cardiopulmonary bypass. Cholesterol crystal embolism (CCE) was demonstrated histologically, but angiograms were typical of non-occlusive mesenteric ischemia (NOMI). Very severe vasoconstriction occurred not only in the superior mesenteric artery but also in other splanchnic arteries. The clinical course strongly suggested that NOMI resulted from CCE and that some humoral factors were released and played very important roles in this case.
 ...
PMID:Possible close relationship between non-occlusive mesenteric ischemia and cholesterol crystal embolism after cardiovascular surgery. 1246 38

The treatment of patients with stable angina has three goals: 1) minimize or eliminate ischemia (silent or symptomatic), 2) reduce morbidity, and 3) decrease mortality. Surgical and now angiographic revascularization procedures are increasingly popular approaches to the management of these patients. The results of randomized, controlled trials suggest that revascularization may not improve survival, but is useful to improve symptoms and exercise capacity. However, these trials are of limited value because they do not reflect current state of the art revascularization techniques or optimal medical management. Because many of these studies were conducted more than a decade ago, patients were recruited before the survival benefits of antiplatelet therapy, b-blockers, angiotensin-converting enzyme inhibitors, and aggressive lipid lowering were accepted. The Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial should help us determine the best approach in these patients. It is a multicenter, randomized trial comparing aggressive medical therapy with aggressive medical therapy with current state of the art percutaneous coronary intervention (PCI) for patients with stable coronary disease. The COURAGE protocol targets global risk reduction emphasizing 1) lifestyle modification, 2) maximal use of drugs to lower blood pressure to Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC) VI goals, 3) maximal use of drugs to lower cholesterol to below National Cholesterol Education Program Adult Treatment Panel III goals for secondary prevention, and 4) maximal use of drug to alleviate anginal symptoms with or without the best interventional devices to conduct PCI.
 ...
PMID:Aggressive medical management of coronary artery disease versus mechanical revascularization. 1257 97

Cholesterol is known to participate in atheromatous plaque formation coming from blood stream and affecting vascular endothelium in environment of elevated low-density lipoproteins (LDL). Nevertheless, the occurrence of single atheromatous plaque evidences the possibility of local lipoprotein accumulation by vascular wall without systemic increase in serum LDLs. The author hypothesizes that in the absence of hypercholesterolemia atheroma can evolve through the utilization of modified LDL and free or etherified cholesterol, that remain in media non-removed by high density lipoproteins (HDL) owing to their structural damage after local vascular wall ischemia caused by vasa vasorum disorders. Disturbances in HDL acceptor function and transport of cholesterol and modified LDL to blood circulation and further into liver are followed by local accumulation of these products in smooth muscle cells. Overloaded by lipids smooth muscle cells move through internal fenestrated membrane thus activating receptor mechanism for transmission of modified lipoproteins to monocytes and capture of endothelial membrane and amorphous lipids by them in local lipid peroxidation area. A framework for hypothesis experimental and clinical testing is suggested.
 ...
PMID:[Pathogenesis of atherosclerosis in patients with lipid metabolism disturbances: hypothesis on cholesterol utilization and atheromatous plaque formation]. 1465 28


<< Previous 1 2 3 4 Next >>