Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The discovery of orally active nonpeptide angiotensin II (A II)-receptor antagonists has initiated a growing understanding of the physiologic and pathophysiologic roles of A II. Losartan is the first of the new class of antagonists that block all the well-known effects of A II, including vasoconstriction, aldosterone release, renin release (negative feedback), and the stimulation of thirst. A II-receptor subtypes have been described, with losartan antagonism defining the AT1 subtype and with PD123319 antagonism defining the AT2 subtype. The AT1 receptor is G-protein-coupled, involving PLC, PLA2, PLD, or adenylate cyclase and the release of intracellular calcium. The receptor-response coupling of the AT2 site remains elusive but may involve protein tyrosine phosphatase and subserve an antiproliferative role. Losartan as the prototype of an AT1-selective antagonist: i) inhibits A II binding, ii) antagonizes effects of A II in vivo and in vitro, and iii) lowers blood pressure in models of A II-dependent hypertension A II stimulates growth in vitro (DNA and protein synthesis) and in vivo (cardiac and vascular hypertrophy), and these effects are blocked by losartan. Losartan, like angiotensin-converting enzyme inhibitors, has significant renal, cardiac, and cerebral protective effects in models of renal failure, cardiac failure, and stroke, confirming the pathologic role of A II in these models. The pioneering studies in experimental animals are being confirmed by a growing number of other AT1-selective blockers and provide the basis of use of losartan for hypertension and its clinical trial in other disease states.
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PMID:The diversified pharmacology of angiotensin II-receptor blockade. 891 41

This is the first Hungarian paper on the platelet glycoprotein IIb/IIIa (LeuPro 33) polymorphism in stroke patients. There are conflicting data about the role of this polymorphism in the pathogenesis of arterial thrombosis. The aim of our study was to describe the prevalence of PLA1/PLA2 in healthy persons and in stroke patients. From the same study population other polymorphism (prothrombin gene 20210 G/A) also has been determined. Blood sample was investigated by polymerase chain reaction in 173 unrelated healthy donors and 234 stroke patients. Stroke was documented by CT and MRI. We used a rutin questionnaire to study previous vascular events and conventional risk factors of patients. Prevalence of PLA1/PLA2 was 23.5% among healthy persons. That is higher than in other European countries (15%). It was 30.4% in stroke patients (OR: 1.42, 95%; CI: 0.87-2.31; p = 0.15). Heterozigous PLA was found in patients older than 50 by 33.6% (OR: 1.65, 95%; CI: 0.94-2.87; p = 0.09). Previous vascular events and conventional risk profil were not significantly different between PLA1/PLA1 and PLA1/PLA2 groups of patients. In patients under 50 having 20-85% stenosis of internal carotid artery there was a higher prevalence (p = 0.09). Comparing stroke patients to control population there was a slight increase (OR: 7.0; p = 0.06) in the frequency of two polymorphisms (PLA and factor II) together in the stroke cases. Polymorphism of GP IIb/IIIa LeuPro 33 seemed to be increased in stroke patients above 50 years. Carotid stenosis with polymorphism is a risk factor for young patients. PLA variant together with prothrombin gene polymorphism results very high risk for stroke.
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PMID:[Platelet glycoprotein IIb/IIIa (LeuPro 33) polymorphism in stroke patients]. 1136 63

Free fatty acids (FFAs) are elevated in the brain following both ischemic and traumatic injury. Phospholipase activation, with the subsequent release of FFAs from membrane phospholipids, is the likely mechanism. In addition to phospholipases A1, B, C, and D, there are at least 19 groups of PLA2, including multiple cytosolic, calcium independent, and secretory isoforms. Phospholipase activity can be regulated by calcium, by phosphorylation, and by agonists binding to G-protein-coupled receptors. These enzymes normally function in the physiological remodeling of cellular membranes, whereby FFAs are removed by phospholipase activity and then reacylated with a different FFA. However, reductions in the cell's ability to maintain normal metabolic function and the resultant fall in ATP levels can cause the failure of reacylation of membrane phospholipids. Alterations to membrane phospholipids would be expected to compromise many cellular functions, including the ability to accumulate excitotoxic amino acids. This review presents evidence for a central role of phospholipases and their products in the etiology of damage following injury to the brain. Phospholipase expression and activity is increased in animal models of cerebral ischemia and trauma. FFA release from the in vivo rat brain is reduced following the application of selective phospholipase inhibitors, and this inhibition also decreases the severity of cortical damage following forebrain ischemia, focal (middle cerebral artery occlusion) ischemia, and cerebral trauma. Mice with knockouts of PLA2 have decreased infarct volumes. Human data demonstrate a correlation between the elevation of CSF FFAs and worsened outcome following stroke, traumatic brain injury, and subarachnoid hemorrhage. The released FFAs, especially arachidonic and docosahexaenoic acids, together with the production of lysophospholipids, can initiate a chain of events which may be responsible for the development of neuronal damage. Inhibitors of both cyclooxygenase and lipoxygenase pathways have been shown to reduce cerebral deficits following ischemia and trauma. These results suggest therapeutic strategies to reduce morbidity following cerebral injury using selective inhibitors of phospholipases, cyclooxygenases, and lipoxygenases, underlining the need for further investigation of their role in the development of cerebral damage.
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PMID:The role of phospholipases, cyclooxygenases, and lipoxygenases in cerebral ischemic/traumatic injuries. 1451 63

The prevalence rates of the platelet glycoprotein IIb/IIIa Leu33Pro allele (PLA2), and factor V G1691A Leiden mutation were determined in 109 appropriate for gestational age neonates with grade I intraventricular haemorrhage (IVH) and in 118 IVH-free control infants. The PLA2 allele frequency was 16.4 % in the group of full-term infants with grade I IVH, while it was 9.5 % in the relevant controls (p < 0.005); there was no difference in the PLA allele frequencies on comparing the IVH affected (8.34 %) and unaffected (9.2 %) premature infants. By contrast, the factor V Leiden allele frequency was increased only in the subgroup of premature infants with grade I IVH as compared with the appropriate premature controls (9.25 % vs. 3.34 %, respectively, p < 0.005). These data suggest that besides the factor V Leiden mutation, the PLA2 allele, which has already been suggested to have a role in neonatal alloimmune thrombocytopenia and certain subtypes of adult stroke, can have significance in the development of the events of IVH.
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PMID:Increased prevalence of glycoprotein IIb/IIIa Leu33Pro polymorphism in term infants with grade I intracranial haemorrhage. 1677 3

Cerebral ischemia initiates an inflammatory response in the brain that is associated with the induction of a variety of cytokines, including tumor necrosis factor-alpha (TNF-alpha) and interleukin-1alpha/beta (IL-1alpha/beta) that contributes to stroke injury. Transient middle cerebral artery occlusion (tMCAO) in spontaneously hypertensive rat (SHR) resulted in significant increases in TNF-alpha and IL-1beta levels. We have previously demonstrated up-regulation of secretory phospholipase A2 IIA (sPLA2 IIA) mRNA and protein expression, increased PLA2 activity, and loss of phosphatidylcholine after 1-h tMCAO and 24-h reperfusion in SHR. Treatment with TNF-alpha antibody or IL-1 receptor antagonist significantly attenuated infarction volume, sPLA2 IIA protein expression, PLA2 activity and significantly restored phosphatidylcholine levels after tMCAO. This suggests that cytokine induction up-regulates sPLA2 IIA protein expression, resulting in altered lipid metabolism that contributes to stroke injury.
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PMID:Secretory phospholipase A2 IIA is up-regulated by TNF-alpha and IL-1alpha/beta after transient focal cerebral ischemia in rat. 2773 30

Circulating lipoprotein-associated phospholipase A2 (Lp-PLA2) is a marker of inflammation that plays a critical role in atherogenesis; its inhibition may have antiatherogenic effects. Studies from the West of Scotland Coronary Prevention Study (WOSCOPS), Monitoring Trends and Determinants in Cardiovascular Diseases (MONICA) and Rotterdam cohorts have shown that Lp-PLA2 is an independent predictor of coronary heart disease (CHD), and the association is not attenuated upon multivariate analysis with traditional risk factors and other inflammatory markers. Studies in subjects with coronary artery disease (CAD) have also shown associations between Lp-PLA2 and cardiovascular risk. At least two recent studies have shown that Lp-PLA2 is a risk predictor for stroke. Overall, epidemiological studies suggest that measurement of Lp-PLA2 in plasma may be a useful in identifying individuals at high risk for cardiovascular events.
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PMID:Lipoprotein-associated phospholipase A2, vascular inflammation and cardiovascular risk prediction. 1731 59

Stroke is the second cause of mortality in industrialized countries. Atherosclerotic plaque rupture with atheromatous debris distal embolization is the pathogenetic mechanism responsible for cerebrovascular events due to atherosclerotic carotid disease. Plaque composition rather than lesion burden seems to be the determinant factor producing rupture and subsequent thrombosis. Histologic features of vulnerability are : a large lipid core, a thin fibrous cap, and an inflammatory infiltrate rich of monocytes and macrophages. In the clinical practice, it is difficult to predict the risk of experiencing a major cerebrovascular events especially in asymptomatic patients. New invasive techniques such as intravascular ultrasound with termography, optical coherence tomography, fotons spectroscopy and elastography have been developed to detect atherosclerotic lesion tissue composition. However, such techniques are difficult to apply on a large scale basis in primary prevention. On the contrary, new serologic biomarkers such as Pregnancy Associated Plasma Protein-A, Lp-PLA2, Interleukin-6, Interleukin-12, metalloproteinases, lipoprotein-(a), and plaque oxidative products have been recently proposed for screening general and high risk population. The present paper will briefly review the current histologic characteristics of vulnerable plaque and the new imaging tools proposed for its detection, focusing on the most recent serologic biomarkers evaluated in the clinical practice to increase our accuracy in predicting not only the plaque but moreover the patient at risk for an acute cerebrovascular event.
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PMID:From carotid plaque biology to serologic markers of vulnerability to predict the risk of cerebrovascular events. 1751 60

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an enzyme that belongs to the superfamily of phospholipase A2 enzymes. Although initial studies showed that Lp-PLA2 might be protective against atherosclerosis, emerging data seem to suggest that Lp-PLA2 may be proatherogenic, which is an effect thought to be mediated by lysophosphatidylcholine and oxidized nonesterified fatty acids, two mediators generated by Lp-PLA2. This article reviews the potential mechanisms by which Lp-PLA2 may participate in the pathogenesis of atherosclerosis and its clinical manifestations, namely, coronary artery disease and stroke.
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PMID:The role of lipoprotein-associated phospholipase A2 as a marker for atherosclerosis. 1787 17

Cytokines regulate the innate and adaptive immune responses and are pleiotropic, redundant and multifunctional. Expression of most cytokines, including TNF-alpha and IL-1alpha/beta, is very low in normal brain. Metabolism of lipids is of particular interest due to their high concentration in the brain. Inflammatory response after stroke suggests that cytokines (TNF-alpha, IL-1alpha/beta, IL-6), affect the phospholipid metabolism and subsequent production of eicosanoids, ceramide, and ROS that may potentiate brain injury. Phosphatidylcholine and sphingomyelin are source for lipid messengers. Sphingomyelin synthase serves as a bridge between metabolism of glycerolipids and sphingolipids. TNF-alpha and IL-1alpha/beta can induce phospholipases (A2, C, and D) and sphingomyelinases, and concomitantly proteolyse phosphatidylcholine and sphingomyelin synthesizing enzymes. Together, these alterations contribute to loss of phosphatidylcholine and sphingomyelin after stroke that can be attenuated by inhibiting TNF-alpha or IL-1alpha/beta signaling. Inflammatory responses are instrumental in the formation and destabilization of atherosclerotic plaques. Secretory PLA2 IIA is found in human atherosclerotic lesions and is implicated in initiation, progression and maturation of atherosclerosis, a risk factor for stroke. Lipoprotein-PLA2, part of apolipoprotein B-100 of LDL, plays a role in vascular inflammation and coronary endothelial dysfunction. Cytokine antagonism attenuated secretory PLA2 IIA actions, suggesting cytokine-lipid integration studies will lead to new concepts contributing to bench-to-bedside transition for stroke therapy.
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PMID:Integration of cytokine biology and lipid metabolism in stroke. 1798 27

Few studies have investigated the role of elevated lipoprotein-associated phospholipase A2 (Lp-PLA(2)) with stroke risk, and those that have are based on small numbers of strokes. No study has evaluated the effect of hormone therapy use on the association of Lp-PLA(2) and stroke. We assessed the relationship between Lp-PLA(2) and the risk of incident ischemic stroke in 929 stroke patients and 935 control subjects in the Hormones and Biomarkers Predicting Stroke Study, a nested case-control study from the Women's Health Initiative Observational Study. Mean (SD) levels of Lp-PLA(2) were significantly higher among case subjects (309.0 [97.1]) than control subjects (296.3 [87.3]; P<0.01). Odds ratio for ischemic stroke for the highest quartile of Lp-PLA(2), compared with lowest, controlling for multiple covariates, was 1.08 (95% CI: 0.75 to 1.55). However, among 1137 nonusers of hormone therapy at baseline, the corresponding odds ratio was 1.55 (95% CI: 1.05 to 2.28),whereas there was no significant association among 737 hormone users (odds ratio: 0.70; 95% CI: 0.42 to 1.17; P for interaction=0.055). Moreover, among nonhormone users, women with high C-reactive protein and high Lp-PLA2 had more than twice the risk of stroke (odds ratio: 2.26; 95% CI: 1.55 to 3.35) compared with women low levels in both biomarkers. Furthermore, different stroke cases were identified as high risk by Lp-PLA(2) rather than by C-reactive protein. Lp-PLA(2) was associated with incident ischemic stroke independently of C-reactive protein and traditional cardiovascular risk factors among nonusers of hormone therapy with highest risk in those who had both high C-reactive protein and high Lp-PLA(2).
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PMID:Lipoprotein-associated phospholipase A2, hormone use, and the risk of ischemic stroke in postmenopausal women. 1825 35


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