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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ischemic disease is a leading cause of death and disability worldwide, and its incidence is expected to increase as the population ages. One population at particularly high risk of developing ischemia is patients with diabetes. Type 2 diabetes is associated with a marked increase in atherosclerosis, stroke and heart attack. Furthermore, the outcome following stroke and heart attack in diabetics is worse than in nondiabetic patients. In recent years, peroxisome proliferator-activated receptor (PPAR) agonists have been found to have potent antiinflammatory actions and have emerged as potential therapies for atherosclerosis and ischemia. The use of these agents is particularly attractive, since two PPARgamma agonists, pioglitazone (Actos) and rosiglitazone (Avandia), are already used chronically to treat diabetes. In this article we review the role of inflammation in ischemic disease and the biology of PPARs, and summarize the evidence that PPARgamma ligands suppress inflammation with an emphasis on atherosclerosis, and cerebral and myocardial ischemia.
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PMID:Antiinflammatory properties of PPARgamma agonists following ischemia. 1533 71

Stroke triggers an inflammatory cascade which contributes to a delayed cerebral damage, thus implying that antiinflammatory strategies might be useful in the treatment of acute ischaemic stroke. Since two unrelated peroxisome proliferator-activated receptor-gamma (PPARgamma) agonists, the thiazolidinedione rosiglitazone (RSG) and the cyclopentenone prostaglandin 15-deoxy-Delta(12,14)-prostaglandin J2 (15d-PGJ2), have been shown to possess antiinflammatory properties, we have tested their neuroprotective effects in experimental stroke. Rosiglitazone or 15d-PGJ2 were administered to rats 10 mins or 2 h after permanent middle cerebral artery occlusion (MCAO). Stroke outcome was evaluated by determination of infarct volume and assessment of neurological scores. Brains were collected for protein expression, gene array analyses and gene shift assays. Our results show that both compounds decrease MCAO-induced infarct size and improve neurological scores. At late times, the two compounds converge in the inhibition of MCAO-induced brain expression of inducible NO synthase and the matrix metalloproteinase 9. Interestingly, at early times, complementary DNA microarrays and gene shift assays show that different mechanisms are recruited. Analysis of early nuclear p65 and late cytosolic IkappaBalpha protein levels shows that both compounds inhibit nuclear factor-kappaB signalling, although at different levels. All these results suggest both PPARgamma-dependent and independent pathways, and might be useful to design both therapeutic strategies and prognostic markers for stroke.
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PMID:Rosiglitazone and 15-deoxy-Delta12,14-prostaglandin J2 cause potent neuroprotection after experimental stroke through noncompletely overlapping mechanisms. 1603 72

Peroxisome proliferator-activated receptor gamma (PPAR-gamma) is a nuclear membrane-associated transcription factor that governs the expression of various inflammatory genes. PPAR-gamma agonists protect peripheral organs from ischemic injury. In the present study, we investigated whether the PPAR-gamma agonist rosiglitazone is neuroprotective against focal ischemic brain injury. C57/B6 mice underwent 1.5-h middle cerebral artery occlusion, and received either vehicle or rosiglitazone treatment of 0.75, 1.5, 3, 6 or 12 mg/kg (n = 9 per group). Cerebral infarct volume, neurological function, expression of pro-inflammatory proteins and neutrophil accumulation were assessed after ischemia and reperfusion. At 48 h after ischemia, infarct volume was significantly decreased with 3-12 mg/kg of rosiglitazone, with a time window of efficacy of 2 h after ischemia at the optimal dose (6 mg/kg). Neutrophil accumulation was significantly decreased in the brain parenchyma of rosiglitazone-treated mice. Ischemia-induced expression of several inflammatory cytokines and chemokines was markedly reduced in rosiglitazone-treated brains, as determined using proteomic-array analysis. Rosiglitazone treatment improved neurological function at 7 days after ischemia. Moreover, in cultured cortical primary microglia, rosiglitazone attenuated inflammatory responses by decreasing lipopolysaccharide-induced release of tumor necrosis factor-alpha, interleukin (IL)-1beta and IL-6. These results suggest that the PPAR-gamma agonist rosiglitazone has neuroprotective properties that are at least partially mediated via anti-inflammatory actions, and is thus a potential novel therapeutic agent for stroke.
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PMID:Neuroprotection against focal ischemic brain injury by the peroxisome proliferator-activated receptor-gamma agonist rosiglitazone. 1653 67

1. Stroke is accompanied by a robust inflammatory response, glutamate-mediated excitotoxicity, release of reactive oxygen species and apoptosis. Thiazolidinediones, which target the nuclear receptor peroxisome proliferator-activated receptor (PPAR)-g, have been reported recently to exhibit potent anti-inflammatory and anti-oxidant actions and inhibit both neural excitotoxicity and apoptosis. 2. The present study was conducted to determine whether rosiglitazone, a potent thiazolidinedione for PPAR-g, would show efficacy against the cerebral infarction and neurological dysfunctions induced by embolic middle cerebral artery (MCA) occlusion in the rat. 3. Focal ischaemic injury was induced by embolizing a preformed clot into the MCA. Rosiglitazone was dissolved in dimethyl sulphoxide and injected i.p. 1 h before MCA occlusion at doses of 0.33, 0.1, 0.3 or 1 mg/kg. In addition, 1 mg/kg rosiglitazone was used immediately or 4 h after embolization. Forty-eight hours after MCA occlusion, brains were removed, sectioned and stained with a 2% solution of 2,3,5-triphenyltetrazolum chloride and analysed using a commercial image-processing software program. 4. When rosiglitazone was administered 1 h before embolization, it significantly reduced infarct volume by 48.2, 68.4% and 70.3% at doses of 0.1, 0.3 and 1 mg/kg, respectively (P < 0.001). Administration of rosiglitazone (1 mg/kg) immediately or 4 h after stroke also reduced infarct volume by 67 and 50.8%, respectively (P < 0.001). Rosiglitazone-treated rats also demonstrated improved neurological functions. However, there were no statistically significant differences between control and treated groups in terms of brain oedema at 48 h after ischaemic injury. 5. The findings of the present study may support the idea of a potential benefit of thiazolidinediones in the management of ischaemic stroke.
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PMID:Rosiglitazone, a peroxisome proliferator-activated receptor-gamma ligand, reduces infarction volume and neurological deficits in an embolic model of stroke. 1704 14

Thiazolidinediones (TZDs) are synthetic agonists of the ligand-activated transcription factor peroxisome proliferator-activated receptor-gamma (PPARgamma). TZDs are known to curtail inflammation associated with peripheral organ ischemia. As inflammation precipitates the neuronal death after stroke, we tested the efficacy of TZDs in preventing brain damage following transient middle cerebral artery occlusion (MCAO) in adult rodents. As hypertension and diabetes complicate the stroke outcome, we also evaluated the efficacy of TZDs in hypertensive rats and type-2 diabetic mice subjected to transient MCAO. Pre-treatment as well as post-treatment with TZDs rosiglitazone and pioglitazone significantly decreased the infarct volume and neurological deficits in normotensive, normoglycemic, hypertensive and hyperglycemic rodents. Rosiglitazone neuroprotection was not enhanced by retinoic acid x receptor agonist 9-cis-retinoic acid, but was prevented by PPARgamma antagonist GW9662. Rosiglitazone significantly decreased the post-ischemic intercellular adhesion molecule-1 expression and extravasation of macrophages and neutrophils into brain. Rosiglitazone treatment curtailed the post-ischemic expression of the pro-inflammatory genes interleukin-1beta, interleukin-6, macrophage inflammatory protein-1alpha, monocyte chemoattractant protein-1, cyclooxygenase-2, inducible nitric oxide synthase, early growth response-1, CCAAT/enhancer binding protein-beta and nuclear factor-kappa B, and increased the expression of the anti-oxidant enzymes catalase and copper/zinc-superoxide dismutase. Rosiglitazone also increased the expression of the anti-inflammatory gene suppressor of cytokine signaling-3 and prevented the phosphorylation of the transcription factor signal transducer and activator of transcription-3 after focal ischemia. Thus, PPARgamma activation with TZDs might be a potent therapeutic option for preventing inflammation and neuronal damage after stroke with promise in diabetic and hypertensive subjects.
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PMID:Peroxisome proliferator-activated receptor-gamma agonists induce neuroprotection following transient focal ischemia in normotensive, normoglycemic as well as hypertensive and type-2 diabetic rodents. 1739 60

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists have been found to have potent anti-inflammatory actions and suggested as potential therapies for brain ischaemia. Glutamate is the most common excitatory neurotransmitter in the central nervous system and is released excessively during ischaemia. Stroke therapy will require combinations of drug classes, because no single drug class has yet been proven efficacious in human beings. The present study was conducted to assess whether N-methyl-d-aspartate (NMDA) receptor antagonist (MK-801) treatment can improve recovery from ischaemic brain injury and whether rosiglitazone, a PPAR-gamma ligand, can increase its neuroprotective effect in an embolic model of stroke. Stroke was induced in rats by embolizing a preformed clot into the middle cerebral artery. Rosiglitazone (0.1 mg/kg, intraperitoneally) and MK-801 (0.1 mg/kg, intravenously) were injected immediately after embolization. Forty-eight hours later, the brains were removed, sectioned and stained with triphenyltetrazolum chloride and analysed by a commercial image processing software programme. Rosiglitazone and MK-801 alone or in combination decreased infarct volume by 49.16%, 50.26% and 81.32%, respectively (P < 0.001). Moreover, the combination therapy significantly decreased the infarct volume when compared to any drug used alone (P < 0.05). MK-801 reduced the brain oedema by 68% compared to the control group (P < 0.05), but rosiglitazone or combination did not show any significant effect. The drugs alone or in combination also demonstrated improved neurological function, but combination therapy was more effective on neurological deficits improving. Our data show that the combination of MK-801 and rosiglitazone is more neuroprotective in thromboembolic stroke than given alone; this effect perhaps represents a possible additive effect in the brain infarction.
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PMID:Combination therapy of rosiglitazone, a peroxisome proliferator-activated receptor-gamma ligand, and NMDA receptor antagonist (MK-801) on experimental embolic stroke in rats. 1791 Jun 13

Thiazolidinediones (TZDs) are widely used in the type 2 diabetes mellitus (DMT2) treatment but have also been tested in cardiovascular prevention. DMT2 is associated with a marked increment in cardiovascular risk, and its prevention represents a main target in cardiometabolic protection. Both Troglitazone (Troglitazone in Prevention of Diabetes study) and Rosiglitazone (Diabetes Reduction Assessment with Ramipril and Rosiglitazone Medication study) significantly reduced new-onset diabetes. A similar topic will be investigated with pioglitazone (Actos Now for Prevention of Diabetes). In the Prospective Pioglitazone Clinical Trial in Macrovascular events the primary end point (all-cause mortality, nonfatal myocardial infarction, stroke, acute coronary syndromes, endovascular or surgical intervention in the coronary/leg arteries and amputation above ankles) was unaffected, whereas the secondary one (all-cause mortality, nonfatal myocardial infarction and stroke) was reduced by pioglitazone (-16%, p=0.027) compared to placebo in 5,238 patients with DMT2 and macrovascular disease. In contrast, a meta-analysis (Nissen and Wolski, N Engl J Med. 2007;356:2457-2471) reported that rosiglitazone treatment is associated with a significant increase in myocardial infarction risk (p=0.03) and a borderline significant increase in the risk of death from cardiovascular causes (p=0.06). Nevertheless, the possibility that rosiglitazone might affect cardiovascular events should be evaluated by the ongoing trial Rosiglitazone Evaluated for Cardiac Outcomes and Regulation of Glycemia in Diabetes (RECORD). Interim findings early from RECORD did not show significant differences between the rosiglitazone and the control group regarding myocardial infarction and death from cardiovascular and any cause. Additional large-scale trials are awaited to clarify the of role TZDs in cardiovascular outcomes.
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PMID:Cardiovascular risk and cardiometabolic protection: role of glitazones. 1903 66

Peroxisome proliferator-activated receptors gamma (PPARgamma) are nuclear receptors with essential roles as transcriptional regulators of glucose and lipid homeostasis. PPARgamma are also potent anti-inflammatory receptors, a property that contributes to the neuroprotective effects of PPARgamma agonists in experimental stroke. The mechanism of these beneficial actions, however, is not fully elucidated. Therefore, we have explored further the actions of the PPARgamma agonist rosiglitazone in experimental stroke induced by permanent middle cerebral artery occlusion (MCAO) in rodents. Rosiglitazone induced brain 5-lipoxygenase (5-LO) expression in ischemic rat brain, concomitantly with neuroprotection. Rosiglitazone also increased cerebral lipoxin A(4) (LXA(4)) levels and inhibited MCAO-induced production of leukotriene B4 (LTB(4)). Furthermore, pharmacological inhibition and/or genetic deletion of 5-LO inhibited rosiglitazone-induced neuroprotection and downregulation of inflammatory gene expression, LXA(4) synthesis and PPARgamma transcriptional activity in rodents. Finally, LXA(4) caused neuroprotection, which was partly inhibited by the PPARgamma antagonist T0070907, and increased PPARgamma transcriptional activity in isolated nuclei, showing for the first time that LXA(4) has PPARgamma agonistic actions. Altogether, our data illustrate that some effects of rosiglitazone are attributable to de novo synthesis of 5-LO, able to induce a switch from the synthesis of proinflammatory LTB(4) to the synthesis of the proresolving LXA(4). Our study suggests novel lines of study such as the interest of lipoxin-like anti-inflammatory drugs or the use of these molecules as prognostic and/or diagnostic markers for pathologies in which inflammation is involved, such as stroke.
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PMID:Synthesis of lipoxin A4 by 5-lipoxygenase mediates PPARgamma-dependent, neuroprotective effects of rosiglitazone in experimental stroke. 1932 84

Rosiglitazone (RGZ), a peroxisome proliferator-activated receptor-gamma (PPAR-gamma), has been shown to provide neuroprotective and anti-inflammatory effects in the acute phase of cerebral ischemia, and traumatic or surgical brain injuries. However, the effect of delayed post ischemia administration of this compound is still unclear. This study was designed to evaluate the neuroprotective effects of RGZ when first administered at 24 h after the embolic model of stroke. Embolic focal cerebral ischemia was induced in rats by placing a preformed clot into the middle cerebral artery (MCA). RGZ (5 mg/kg, intraperitoneally) was injected at 24 and 48 h after MCA embolization. Neurological deficits were evaluated at 24, 48 and 72 h after stroke, and blood and brain tissues were then collected for differential blood cell counts and assessments of infarct volume and DNA fragmentation, respectively. Compared to the control group, the administration of RGZ, starting 24 h after cerebral ischemia, reduced infarct volume by 56% (P<0.05) and decreased neurological deficits at 72 h after cerebral ischemia (P<0.05). Also, delayed administration of RGZ prevented neutrophilia in blood (P<0.005) and significantly decreased DNA fragmentation (P<0.05), 72 h after MCA occlusion. Therefore, our data demonstrate that treatment with RGZ, starting 24 h after stroke, can reduce ischemic injury, improve neurological outcome, and prevent neutrophilia. These findings may support the idea that RGZ has an extended therapeutic window for the treatment of ischemic stroke, as it targets delayed pathways.
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PMID:Delayed post ischemic treatment with Rosiglitazone attenuates infarct volume, neurological deficits and neutrophilia after embolic stroke in rat. 1933 33

We investigated cardiac hypertrophy elicited by rosiglitazone treatment at the level of protein synthesis/degradation, mTOR, MAPK and AMPK signalling pathways, cardiac function and aspects of carbohydrate/lipid metabolism. Hearts of rats treated or not with rosiglitazone (15 mg/kg day) for 21 days were evaluated for gene expression, protein synthesis, proteasome and calpain activities, signalling pathways, and function by echocardiography. Rosiglitazone induced eccentric heart hypertrophy associated with increased expression of ANP, BNP, collagen I and III and fibronectin, reduced heart rate and increased stroke volume. Rosiglitazone robustly increased heart glycogen content ( approximately 400%), an effect associated with increases in glycogenin and UDPG-PPL mRNA levels and glucose uptake, and a reduction in glycogen phosphorylase expression and activity. Cardiac triglyceride content, lipoprotein lipase activity and mRNA levels of enzymes involved in fatty acid oxidation were also reduced by the agonist. Rosiglitazone-induced cardiac hypertrophy was associated with an increase in myofibrillar protein content and turnover (increased synthesis and an enhancement of calpain-mediated myofibrillar degradation). In contrast, 26S beta5 chymotryptic proteasome activity and mRNA levels of 20S beta2 and beta5 and 19S RPN 2 proteasome subunits along with the ubiquitin ligases atrogin and CHIP were all reduced by rosiglitazone. These morphological and biochemical changes were associated with marked activation of the key growth-promoting mTOR signalling pathway, whose pharmacological inhibition with rapamycin completely blocked cardiac hypertrophy induced by rosiglitazone. The study demonstrates that both arms of protein balance are involved in rosiglitazone-induced cardiac hypertrophy, and establishes the mTOR pathway as a novel important mediator therein.
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PMID:Rosiglitazone-induced heart remodelling is associated with enhanced turnover of myofibrillar protein and mTOR activation. 1939 13


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