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

Hyperhomocysteinemia (HHcy) is an independent risk factor for cardiovascular disease, including ischemic heart disease, stroke, and peripheral vascular disease. Mutations in the enzymes responsible for homocysteine metabolism, particularly cystathionine beta-synthase (CBS) or 5,10-methylenetetrahydrofolate reductase (MTHFR), result in severe forms of HHcy. Additionally, nutritional deficiencies in B vitamin cofactors required for homocysteine metabolism, including folic acid, vitamin B6 (pyridoxal phosphate), and/or B12 (methylcobalamin), can induce HHcy. Studies using animal models of genetic- and diet-induced HHcy have recently demonstrated a causal relationship between HHcy, endothelial dysfunction, and accelerated atherosclerosis. Dietary enrichment in B vitamins attenuates these adverse effects of HHcy. Although oxidative stress and activation of proinflammatory factors have been proposed to explain the atherogenic effects of HHcy, recent in vitro and in vivo studies demonstrate that HHcy induces endoplasmic reticulum (ER) stress, leading to activation of the unfolded protein response (UPR). This review summarizes the current role of HHcy in endothelial dysfunction and explores the cellular mechanisms, including ER stress, that contribute to atherothrombosis.
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PMID:Role of hyperhomocysteinemia in endothelial dysfunction and atherothrombotic disease. 1524 79

Background: Stroke mainly affects the older population, although it has also been reported in younger patients. In this study, we focused on patients 65 years of age or younger with stroke. Methods: The files of three patient populations were studied: 93 patients aged 65 years or younger with stroke (group A), 93 patients older than 65 with stroke (group B), and 604 patients without stroke representing the general population of patients admitted to our service during January 2000 (group C). We reviewed the patient files and compared patient characteristics, epidemiological features, clinical picture,imaging findings, and coagulation tests. Results: Overall, 318 patients were studied. The mean age of group A was 55 years compared to 77 years in group B and 71 years in group C. In both stroke groups (A and B), the male: female ratio was 2:1, in contrast with a balanced ratio in group C. Most of the patients in group A (63%) were of Sephardic origin compared to 39% in group B (P=0.002) and 30% in group C. The clinical picture in both stroke groups (A and B) was similar. The risk factor smoking was reported by 45% in group A and by only 29% in group B (P=0.034). Hypertension, diabetes mellitus, and hyperlipidemia were evenly prevalent in both stroke groups. The coagulation system was studied in the "young" patients (group A): hyperhomocysteinemia was found in 37%, high titers of anticardiolipin antibodies in 35%, low levels of antithrombin III in 13%, protein C deficiency in 5%, and activated protein C resistance (APCR) in 4%. Overall, 49% of the patients from group A were found to have coagulation abnormalities. Conclusions: We found in our study that the younger patient with stroke tends to be a Sephardic male with the classical risk factors as well as a history of smoking and coagulopathy. These findings suggest strict medical supervision and primary prophylaxis. This work also lays the basis for a prospective, interventional trial with younger patients.
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PMID:Clinical and ethnic characteristics of stroke in an Israeli population: a study in a community hospital population. 1524 19

There is growing evidence that chronic alcoholism is associated with a derangement in the sulfur amino acid metabolism. Excitatory aminoacids such as glutamate, aspartate, and homocysteine have been shown to be increased in patients with chronic alcoholism who underwent alcohol withdrawal. Furthermore, sustained hyperhomocysteinemia occurred in chronic alcoholics with active drinking pattern. Excitotoxicity can be induced by increased hormocysteine levels via rebound activation of NMDA receptor-mediated glutamatergic neurotransmission upon the removal of ethanol-evoked inhibition. Therefore, hyperhomocysteinemia may be responsible for the higher incidence of complications during alcohol withdrawal (e.g.stroke,convulsions). In addition, an association between brain atrophy and increased levels of homocysteine in chronic alcoholism was shown. This may have important implications for the pathogenesis of brain atrophy in alcoholics. Taking into account that high plasma homocysteine levels are helpful in the prediction of alcohol withdrawal seizures, early anti-convulsive therapy could prevent this severe complication. Supplementation of folate, a cofactor of the homocysteine metabolism, lowers raised homocysteine levels and therefore could be established as a new therapeutic strategy in alcohol withdrawal treatment. The results of various studies highlight the need for further research to prove whether alcoholics benefit from a reduced homocysteine level with respect to both, alcohol-related disorders and alcohol withdrawal symptoms.
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PMID:[Folate against hyperhomocysteinemia. A new approach for the prevention and therapy of alcoholism-associated disorders?]. 1525 82

This is the case of a 28-year-old woman in apparently good health, who had an ischemic stroke and significant proteinuria developed during her first attempt of in vitro fertilization. She was evaluated for inherited and acquired thrombophilia and tested positive for high titer of antiphospholipid antibodies and mild hyperhomocysteinemia. The potential thrombotic risks associated with in vitro fertilization will be discussed.
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PMID:Homocysteine and antiphospholipid antibodies in a woman undergoing ovarian follicular stimulation: prospective clinical and laboratory evaluation. 1529 97

Changes in serum homocysteine (Hcy), often related to stroke and vascular dementia, are negatively correlated with changes in serum insulin-like growth factor 1 (IGF-1) and growth hormone (GH) replacement decreases Hcy levels in men with GH deficiency. Very little information on the effects of Chinese medicines on GH and Hcy is available in the literature published in English. In this study, the effects of a Chinese medicine suppository, Vigconic VI-28 (VI-28), consisting of concentrated extracts of a composite mixture of herbal materials, on serum IGF-1 and Hcy were studied. In vivo observations after treatment with Chinese medicines have often indicated changes in biochemical profiles of measurable parameters related to those changes in endocrine secretions. Thirty six healthy males (age 47-66) were under observation over a 16-week schedule after using VI-28 suppository from 0 to 12 weeks. Blood specimens were taken monthly (except at the end of week 8) for analysis of Hcy and IGF-1 levels. Compared with week 0, IGF-1 levels (192.5 +/- 66.4 ng/ml) were significantly elevated at week 4 (211.7 +/- 80.5, p < 0.05) and week 12 (226.6 +/- 95.2 ng/ml, p = 0.01). No significant changes were observed for Hcy for the whole cohort from week 0 to week 16. When the cohort was divided into 2 groups using a Hcy level of 13.0 micro mol/l as the cut-off, a significant (p < 0.05) difference in IGF-1 was observed between the 2 groups at week 12 only. The mean IGF-1 of 14 subjects with higher Hcy levels was lower than that of the 22 subjects with lower Hcy. We believe that VI-28 may exert a regulatory effect on the relationship between Hcy and IGF-1, at least in subjects with relatively low levels of Hcy. In addition, we also observed an apparent association of hyperhomocysteinemia (Hcy> or =13.0 micromol/l) with decreased IGF-1.
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PMID:A panel study on the effects of a Chinese medicinal suppository, Vigconic VI-28, on insulin-like growth factor 1 and homocysteine in healthy men. 1531 14

Patients with ischemic stroke are sometimes found to have an underlying inherited (deficiency of protein C, protein S, antithrombin III, activated protein C resistance, prothrombin gene mutation, hyperhomocysteinemia) or acquired thrombophilia (lupus anticoagulant and anticardiolipin antibodies, hyperhomocysteinemia). Patient selection for thrombophilia screening is, therefore, a frequent question in managing patients with ischemic stroke. In this review we discuss patient selection and timing for laboratory tests for thrombophilia screening in stroke patients based on a literature review and we calculated overall costs per year in Germany for testing patients older than 18 years with an ischemic stroke of undetermined cause. As there is a lack of studies comparing anticoagulation with antiplatelet therapy in patients with diagnosed thrombophilia, laboratory screening for thrombophilia even in a selected group of patients with cryptogenic ischemic stroke remains of questionable value at present. An exception appears to be testing for lupus anticoagulant and anticardiolipin antibodies in younger patients with suspected antiphospholipid syndrome (two positive test results necessary), because anticoagulation seems to be superior to aspirin in patients with antiphospholipid syndrome.
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PMID:[Thrombophilias in patients with ischemic stroke. Indication and calculated costs for evidence-based diagnostics and treatment]. 1533 41

Hyperhomocysteinemia is an independent risk factor for atherothrombotic cerebral stroke. Vitamin B12 and folic acid are important determinants of homocysteine metabolism. We aimed to evaluate the relationship, if present, between vitamin B12 and folic acid levels and acute cerebral stroke in this study. Blood aliquots drawn within 24 hours after the stroke from hospitalized patients (n=66) with the diagnosis of acute ischemic cerebrovascular episode and also blood samples from 38 healthy controls without any vascular risk factor were analyzed. With a competitive, chemoluminescence assay, serum levels of vitamin B12 and folic acid were measured in blood samples taken within 24 hours after the stroke. The differences and correlations were tested using frequency test, student-t test and multivariate analysis. Mean serum vitamin B12 levels were significantly lower in the patients than in the control subjects, 245.40 (S.D.: 72.9) and 343.2 (S.D.: 113.0) pg/ml respectively (p=0.0001). This difference was independent from other risk factors. Likewise, mean serum folic acid levels were lower in the patients than in the control subjects, 4.62 (S.D.: 1.94) and 5.97 (S.D.: 1.19) ng/ml, respectively (p=0.003). Mean serum levels of vitamin B12 and folate at the convalescence phase were 253.05 (S.D.: 68.78) pg/ml and 4.48 (S.D.: 2.08) ng/ml, respectively; the values obtained at the acute phase were not significantly different from the values obtained at the convalescence phase. We conclude that low vitamin B12 and folic acid concentrations are associated with an increased risk of stroke, and the relationship for vitamin B12 is independent from the other known modifiable stroke risk factors. For understanding the effects of B12 and folate in stroke patients, more detailed follow-up studies with long period are needed.
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PMID:Serum vitamin B12 and folic Acid levels in acute cerebral atherothrombotic infarction. 1538 96

Homocysteine (Hcy) is a by-product of methionine metabolism. An imbalance of Hcy in the body may lead to hyperhomocysteinemia, a condition with elevated Hcy concentration in blood that may be one of the risk factors responsible for the development of several vascular diseases (thromboembolism, atherosclerosis, stroke, vascular diseases and dementia). Radix Salvia miltiorrhiza (Danshen), a well-known Chinese medicinal herb that can activate and improve blood microcirculation, is noticeable for its beneficial effect in treating cardiovascular diseases. The present study is to demonstrate the protective effect of Danshen extract against the homocysteine-induced adverse effect on human umbilical vein endothelial cell (HUVEC). Homocysteine (5 mM) not only decreased the cell viability but also caused the disruption of capillary-like structure formation in vitro. The protective effect of Danshen aqueous extract and its active compounds on endothelial cell function were demonstrated through an in vitro tube formation assay, which mimics the new blood vessel formation. To identify the active components in the aqueous extract of Danshen, the content was characterized by instrumental analysis using high performance liquid chromatography with diode array detector (DAD) and electrospray tandem mass spectrometry (ESI-MS/MS). Interestingly, Danshen extract and its pure compounds showed different effectiveness in protecting HUVEC against Hcy-induced injury according to the following descending order: Danshen aqueous extract, 3-(3,4-dihydroxy-phenyl)-2-hydroxy-propionic acid (Danshensu), protocatechuic acid, catechin and protocatechualdehyde. We believed that such findings might provide evidence in understanding the beneficial effects of Danshen on the cardiovascular system.
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PMID:Protective effects of Danshensu from the aqueous extract of Salvia miltiorrhiza (Danshen) against homocysteine-induced endothelial dysfunction. 1548 95

In the general population, hyperhomocysteinemia is an independent risk factor for cardiovascular disease (ischemic disease, such as stroke and myocardial infarction, and arterial and venous thrombosis). We can presume that the association is causal, based on the example of homocystinuria, and on the evidence put forward by several basic science and epidemiologic studies. However, the results of large intervention trials, which may grant further support to this hypothesis, are not yet available. In chronic renal failure and in uremia, the evidence that is offered by carefully performed prospective studies also indicate the presence of an association, although some studies suggest reverse epidemiology. The mechanisms underlying the association, and able to explain the several toxic effects of homocysteine, related or not to cardiovascular disease, are unclear. Oxidation, nitrosylation, and hypomethylation are among the postulated mechanisms. In uremia, protein hypomethylation interferes with protein repair; DNA hypomethylation impairs regulation of gene expression, whereas folate treatment reverts such alterations. Acylation, another structural modification able to impair protein function, is a possible mediator of homocysteine toxicity.
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PMID:Hyperhomocysteinemia and cardiovascular disease in uremia: the newest evidence in epidemiology and mechanisms of action. 1549 Apr 4

Hyperhomocysteinemia is thought to cause ischemic strokes. We report two middle-aged widowers with frequent recurrences of small-artery strokes, two capsular infarcts and a thalamic hemorrhage in one patient, and two thalamic and pontine infarcts in the other. Blood tests following the final stroke showed hyperhomocysteinemia and methylenetetrahydrofolate reductase C677T gene mutation, with low concentration of vitamin B6. Multivitamin supplementation normalized plasma homocysteine levels in both patients. Hyperhomocysteinemia is treatable; therefore, serum homocysteine should be measured as a potential risk factor for stroke recurrence in relatively young patients with recurrent small-artery infarctions or hemorrhage, especially those with insufficient lifestyle factors.
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PMID:Recurrent small-artery disease in hyperhomocysteinemia: widowers' stroke syndrome? 1549 8


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