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)

Retrospective and cross-sectional studies have suggested that both bacterial and viral infections may be risk factors for atherosclerosis, ischemic stroke and acute coronary events. The correlation between Chlamydia pneumoniae and atherosclerosis remains a source of controversy. Our case-control study is aimed at evaluating the frequency of C. pneumoniae infection in a cohort of young adults with recent cerebrovascular disease and in particular etiologic stroke subtypes. Chlamydia pneumoniae IgG, IgM and IgA antibodies were evaluated by microimmunofluorescence method and antibody titers to both recombinant antigens chlamydial outer protein 2 and 60-kDa chlamydial heat shock protein (HSP60) by ELISA. The two groups differed with regard to the prevalence of C. pneumoniae IgA (P < 0.001) and IgG (P < 0.0001), as well as the titer of anti-R-HSP60 IgG (P < 0.001). We found an increase in IgA titers, suggestive of persistent, chronic active infection, in 16 patients in whom the etiology of the cerebral ischemic event was large-vessel atherothrombosis. Persistent, active C. pneumoniae infection may be an additional risk factor for ischemic stroke mainly of atherotrombotic origin in young subjects. However, a large-scale prospective confirmation of our findings is required.
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PMID:Chlamydia pneumoniae infection in young stroke patients: a case--control study. 1514 25

chlamdAs with other organ systems, the vulnerability of the nervous system to infectious agents increases with aging. Several different infectious agents can cause neurodegenerative conditions, with prominent examples being human immunodeficiency virus (HIV-1) dementia and prion disorders. Such infections of the central nervous system (CNS) typically have a relatively long incubation period and a chronic progressive course, and are therefore increasing in frequency as more people live longer. Infectious agents may enter the central nervous system in infected migratory macrophages, by transcytosis across blood-brain barrier cells or by intraneuronal transfer from peripheral nerves. Synapses and lipid rafts are important sites at which infectious agents may enter neurons and/or exert their cytotoxic effects. Recent findings suggest the possibility that infectious agents may increase the risk of common age-related neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and stroke. While scenarios can be envisioned whereby viruses such as Chlamydia pneumoniae, herpes simplex and influenza promote damage to neurons during aging, there is no conclusive evidence for a major role of these pathogens in neurodegenerative disorders. In the case of stroke, blood vessels may be adversely affected by bacteria or viruses resulting in atherosclerosis.
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PMID:Infectious agents and age-related neurodegenerative disorders. 1516 5

Previous studies have shown a peak occurrence of ischemic stroke in the morning but no consistent finding has been attributed to this. Focused on lacunar strokes we performed a prospective study with a detailed diagnostic protocol including parameters of recent infection, indicators of sleep apnea and cerebral vasoreactivity (CVR), aimed at defining differences in risk profiles between diurnal and nocturnal strokes. Consecutively we included 33 nocturnal and 54 diurnal strokes. Baseline characteristics, known risk factors, stroke severity and topology were not different between groups. The mean low-density lipoprotein (LDL) cholesterol level was significantly higher amongst patients with nocturnal strokes (133.3 +/- 35.2 mg/dl vs. 115.5 +/- 39.8 mg/dl; P = 0.04), as well as the proportion of patients with any dyslipidemia (94% vs. 77.8%; P = 0.047). Twenty-four-hour blood pressure recordings showed a reduced nocturnal decrease of blood pressure in subjects with strokes that occurred between 10 pm and 6 am in comparison with those whose strokes occurred between 6 am and 2 pm (5.0 +/- 7.3% vs. 11.0 +/- 6.7%; P = 0.049). No significant differences were found for parameters of recent infection (including seroreactivity against Chlamydia pneumoniae and cytomegalovirus), CVR, indicators of sleep apnea and the degree of white matter disease assessed by magnetic resonance tomography. Dyslipidemia, especially elevated LDL cholesterol is more prevalent in nocturnal lacunar strokes especially when combined with a reduced nocturnal dipping of blood pressure. This risk factor profile can be regarded as an additional target for stroke prevention.
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PMID:Dyslipidemia, elevated LDL cholesterol and reduced nocturnal blood pressure dipping denote lacunar strokes occurring during nighttime. 1552 95

During the last two decades, there has been an increasing interest in the impact of oral health on atherosclerosis and subsequent cardiovascular disease (CVD). The advent of the inflammation paradigm in coronary pathogenesis stimulated research in chronic infections caused by a variety of micro-organisms-such as Chlamydia pneumoniae, Helicobacter pylori, and cytomegalovirus-as well as dental pathogens, since these chronic infections are thought to be involved in the etiopathogenesis of CVD by releasing cytokines and other pro-inflammatory mediators (e.g., C-reactive protein [CRP], tumor necrosis factor [TNF-alpha]) that may initiate a cascade of biochemical reactions and cause endothelial damage and facilitate cholesterol plaque attachment. Yet, due to the multi-factorial nature of dental infection and CVD, confirming a causal association is difficult, and the published results are conflicting. The main deficit in the majority of these studies has been the inadequate control of numerous confounding factors, leading to an overestimation and the imprecise measurement of the predictor or overadjustment of the confounding variables, resulting in underestimation of the risks. A meta-analysis of prospective and retrospective follow-up studies has shown that periodontal disease may increase the risk of CVD by approximately 20% (95% confidence interval [CI], 1.08-1.32). Similarly, the reported risk ratio between periodontal disease and stroke is even stronger, varying from 2.85 (CI 1.78-4.56) to 1.74 (CI 1.08-2.81). The association between peripheral vascular disease and oral health parameters has been explored in only two studies, and the resultant relative risks among individuals with periodontitis were 1.41 (CI 1.12-1.77) and 2.27 (CI 1.32-3.90), respectively. Overall, it appears that periodontal disease may indeed contribute to the pathogenesis of cardiovascular disease, although the statistical effect size is small.
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PMID:Oral health, atherosclerosis, and cardiovascular disease. 1557 81

Chlamydia pneumoniae has been linked with increased risk of cardiovascular disease, but data on stroke are sparse. We examined whether seropositivity to Chlamydia pneumoniae was associated with the risk of ischemic stroke in a nested case-control study. Data on Chlamydia pneumoniae serology, lifestyle factors, and medical history were obtained at baseline. Verified cases (n = 254) were compared with gender- and age-matched controls (n = 254). Positive IgA (> or = 1:16) or IgG (> or = 1:64) titers were associated with an increased risk of acute ischemic stroke, i.e. adjusted odds ratios (ORs) were 1.54 (95% confidence interval, CI: 0.96-2.47) and 1.28 (95% CI: 0.83-1.95). The adjusted OR was 1.77 (95% CI: 1.04-3.00) when both titers were elevated. The highest point estimates were seen for ischemic stroke due to large-artery atherosclerosis, adjusted OR: 6.32 (95% CI: 0.76-52.61) (IgG (> or = 1:64)). No clear associations were found for other types of ischemic stroke. The strength of the association varied depending on gender and the chosen cut-off values for the antibody titers. These results partly support the hypothesis that serologic evidence of Chlamydia pneumoniae infection may be associated with an increased risk of ischemic stroke. However, the risk may differ according to gender, subtype of ischemic stroke, and cut-off value of antibody titers.
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PMID:Chlamydia pneumoniae seropositivity and risk of ischemic stroke: a nested case-control study. 1575 5

Tissue remodeling by matrix metalloproteinases (MMPs) and plasminogen activators such as tissue factor (TF) is postulated to be involved in the pathogenesis of atherosclerosis. The in situ expression of MMP9 and TF in unstable atherosclerotic plaques has not been examined in detail. Moreover, interference of tissue remodeling by vascular inflammation, apoptosis, and Chlamydia pneumoniae inside plaque subregions is unclear. A total of 40 autopsy carotid arteries (controls) and 20 atherosclerotic carotid endarterectomy specimens (with type VI lesions, according to the American Heart Association classification) from stroke patients were analyzed for expression of MMP9 and TF using in situ techniques. The data on tissue remodeling were correlated with the presence of inflammatory cells (T cells, B-cells, macrophages), apoptosis, and the presence of C. pneumoniae using immunohistochemistry and Western blot analyses. We found a significant overexpression of MMP9 and TF in progressive atherosclerotic carotid arteries, especially in the shoulder and cap subregions (both p < 0.05). Expression of MMP9 and TF correlated significantly with T-cell and macrophage infiltrates as well as with apoptosis (p < 0.05). C. pneumoniae infection was significantly associated with elevated TF expression (p < 0.01) but not with MMP9. MMP9 and TF are thus significantly overexpressed in progressive atherosclerotic plaques, and their relevant subregions (shoulder and cap) are involved in plaque instability. This process is associated with local inflammatory cell infiltrates and apoptosis, which might be influenced by infectious agents such as C. pneumoniae.
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PMID:Overexpression of MMP9 and tissue factor in unstable carotid plaques associated with Chlamydia pneumoniae, inflammation, and apoptosis. 1581 57

An association of the obligatory intracellular gram-negative pathogen Chlamydia pneumoniae with coronary artery disease, myocardial infarction, and atherosclerosis was suggested. The presence of C pneumoniae was determined in different arteries (n = 165) from 23 control cases and 10 patients with stroke including coronary arteries, carotid arteries, basilar artery, and middle cerebral arteries of normal controls and patients with stroke using nested polymerase chain reaction (PCR) and immunohistochemistry (IHC). Atherosclerosis was detected in 51.5% of all investigated arteries. No significant differences were detected between controls (59.1% by IHC, 45.5% by nested PCR) and patients with stroke (40% by IHC, 40% by nested PCR). This is the first investigation demonstrating C pneumoniae by IHC and nested PCR in different intracerebral arteries in control persons and patients with stroke. No significant correlation between the presence of chlamydial DNA or antigens in arteries and stroke could be demonstrated. The presence of the C pneumoniae is indicative of a correlation between infection and atherosclerosis, but not of a specific vascular neuropathology such as stroke.
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PMID:Identification of Chlamydia pneumoniae in intracranial and extracranial arteries in patients with stroke and in controls: combined immunohistochemical and polymerase chain reaction analyses. 1589 1

Case-control studies and a few prospective studies have indicated that chronic infections may add to the risk of stroke and that acute infections may act as trigger factors for stroke. Such chronic infections include periodontal disease, infection with Chlamydia pneumoniae or Helicobacter pylori, and chronic bronchitis. A causal role of these infectious diseases has not been proved, given conflicting study results, possible residual confounding in observational studies, and the lack of evidence from interventional trials. Therefore, special treatment regimens for stroke prevention based on serologic or genomic evidence of infection are not indicated outside of randomized studies at present. However, the preliminary available evidence suggests that in patients with previous cerebral ischemia, clinically diagnosed chronic infections should be taken seriously and should receive the treatment that is indicated according to current guidelines. This may include appropriate treatment of moderate or severe periodontitis and of chronic bronchitis. Inflammatory parameters (eg, C-reactive protein, leukocyte count, fibrinogen) are independently associated with the risk of first or recurrent stroke. The question of whether these indexes are causally related to stroke or merely represent risk markers is not sufficiently clarified. Their use in monitoring individual risk in daily clinical practice is limited at present by the lack of clearly defined therapeutic strategies to modify these parameters, although statins and other drugs can influence inflammatory markers. Observational studies have shown that influenza vaccination is significantly and independently associated with a reduced risk of stroke and myocardial infarction. Although interventional studies in stroke are lacking, it is recommendable that in accordance with current guidelines patients with previous vascular disease, including stroke, patients with high risk of stroke, and all subjects above age 60, receive an influenza vaccination annually.
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PMID:Role of anti-infective strategies in the prevention of stroke. 1600 50

There is increasing evidence that, in addition to conventional risk factors, acute and chronic infectious diseases increase the risk of stroke. Acute infection, mainly respiratory, and both bacterial and viral infection, represent temporarily active trigger factors for cerebral ischemia. Chronic infectious diseases that may increase the risk of stroke include periodontitis, chronic bronchitis and infections with microbial antigens, such as Helicobacter pylori and Chlamydia pneumoniae. From observational studies, there is evidence that vaccination against influenza is associated with a reduced risk of stroke, myocardial infarction and all-cause mortality. This report provides an overview on the influence of infection on stroke risk and potential anti-infective strategies that may play a future role in stroke prevention.
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PMID:The effect of infections and vaccinations on stroke risk. 1646 97

Infections have long been recognized as a potential, if uncommon, cause of cerebrovascular disease. In recent years, with the growing recognition of the importance of inflammation in atherosclerosis, there has been renewed interest in the possibility that common infections may participate in the atherosclerotic process or lead to stroke through other mechanisms. Specific organisms that have been implicated include Chlamydia pneumoniae, herpes viruses, human immunodeficiency virus, Helicobacter pylori, and organisms associated with periodontal infections. This article outlines the epidemiological, pathological, and laboratory evidence that these infections may be associated with atherosclerosis and stroke. Although definitive proof of an association between a specific infection and stroke is generally lacking, the accumulating evidence does indicate that several types of infections may be among the modifiable risk factors that contribute to the risk of stroke.
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PMID:Do common infections cause stroke? 1647 47


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