UMLS:C0020473 - FACTA Search

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Query: UMLS:C0020473 (hyperlipidemia)
15,891 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Asian Indians who have settled overseas and those in urban India have increased risk of coronary events. Reasons for this increased risk are thought to be genetic but are yet unclear. Advances in molecular cardiology have revealed a number of single nucleotide polymorphisms associated with atherosclerosis. In this review, gene polymorphisms that have been associated with coronary diseases among Indians are discussed. Topics include the genes involved in hyperlipidemia, hypertension, and homocysteine. Mutations in the low-density lipoprotein receptor (LDLR) gene resulting in familial hypercholesterolemia have strong association with premature atherosclerosis. Common polymorphism of the apolipoproteins (apo) B-100 and E genes have been associated with variation in lipid and lipoprotein levels. Recently identified polymorphisms in the apoC3 (T-455C, C-482T), and cholesteryl ester transfer protein (CETP) (B1/B2 allele) genes are associated with increased triglycerides and reduced high-density lipoprotein (HDL)-levels, a feature now also common among Asian Indians. Angiotensin-converting enzyme-deletion (DD) polymorphism has been shown to influence beta-blocker therapy in heart failure. Mutations in methylenetetrahydrofolate reductase (C667T), cystathionine beta-synthase (T833C), and methionine synthase (A2756G) genes cause hyperhomocysteinemia, an independent risk factor for atherothrombosis. As the genetics of atherosclerosis continues to evolve, these factors along with the newer emerging factors may become a part of the routine assessment, aiding prediction of future coronary events.
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PMID:Gene polymorphism and coronary risk factors in Indian population. 1247 35

Cardiac allograft vasculopathy is the most aggressive form of atherosclerosis in humans and is the leading cause of death after the first year of heart transplantation. Endothelial dysfunction is a major contributing factor to the acceleration of coronary vascular disease in these individuals. A reflection of this endothelial dysfunction is the severe impairment in endothelium-dependent vasodilation that occurs early after transplantation. The etiology of this allograft endothelial alteration is multifactorial and may include preexisting atherosclerosis of the graft vessels, reperfusion injury during transplantation, denervation, disruption of the lymphatic system, and acute and chronic immune injury, as well as traditional risk factors for coronary artery disease (hyperlipidemia, diabetes, hypertension, or hyperhomocysteinemia) and pathogens, such as cytomegalovirus. The alteration in endothelial function affects vasomotor tone of the coronary arteries. Evidence indicates that there may be an impairment of endothelial production and/or activity of NO. Because NO is a potent vasodilator, its deficiency would explain the abnormal vasomotor tone in these individuals. In addition, because NO inhibits key processes in vascular inflammation and atherosclerosis, its absence may contribute to the acceleration of transplant vascular disease. Recent studies from our group and others have shed light on the mechanisms of endothelial dysfunction and its importance in cardiac allograft vasculopathy. In addition, the alteration in endothelial function contributes to vascular inflammation and progression of the disease.
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PMID:Cardiac allograft vasculopathy and dysregulation of the NO synthase pathway. 1264 81

Most cross-sectional and case-control studies indicate that an increased plasma total homocysteine (tHcy) level is an independent risk factor for coronary artery disease (CAD). However, this is still a controversial issue. Recently, it was reported that the level of tHcy is related to the extent and severity of CAD. This study was designed to investigate the relationship between plasma tHcy levels and the presence, extent, and severity of CAD. Three hundred and forty-one patients who underwent coronary angiography were included in the study. Of these patients, 195 had CAD and 146 had normal coronary arteries (control group). The mean tHcy level was found to be higher in patients with significant CAD (16.4 +/- 7.4 micromol/L vs 13.2 +/- 3.6 micromol/L, P < 0.001). This group also had a higher rate of hyperhomocysteinemia (HHcy) (22.6% vs 5.5%, P < 0.001). There were positive relationships between tHcy levels and male gender (P = 0.03, r = 0.16), smoking (P < 0.001, r = 0.19), hyperlipidemia (P = 0.006, r = 0.15), and hypertension (P < 0.001, r = 0.20). Using regression analysis HHcy was determined to be an independent risk factor for CAD (OR = 3.69, CI 95% 1.51-9.06, P = 0.004). However, HHcy was not an independent risk factor in patients with low cardiovascular risk profiles. There was no relationship between the level of tHcy and the severity, extent, and vessel scores of CAD. On the other hand, age and diabetes mellitus were related with all scores of CAD. In conclusion, although hyperhomocysteinemia is an independent risk factor for CAD in our region, it appears to be unrelated to the extent and severity of the disease.
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PMID:The effects of hyperhomocysteinemia on the presence, extent, and severity of coronary artery disease. 1282 3

Hyperhomocysteinemia is regarded as an independent risk factor for cardiovascular disease. Lipid-lowering agents, such as fibrates, can modify homocysteine levels. However, less is known about the effect of statin therapy on homocysteine. The authors compared the effects of atorvastatin (40 mg/day), simvastatin (40 mg/day), and micronized fenofibrate (200 mg/day) on the serum concentrations of total homocysteine, vitamin B12, and folic acid in patients with primary hyperlipidemia. A total of 128 patients with primary hyperlipidemia (total cholesterol > 240 mg/dL and triglycerides < 350 mg/dL) were assigned to atorvastatin, simvastatin, or fenofibrate. Serum lipid and metabolic parameters were measured at baseline and at 6 and 12 weeks of treatment. Homocysteine correlated positively with serum creatinine and uric acid levels and inversely with serum folic acid levels. All treatment modalities reduced total, low-density lipoprotein (LDL) cholesterol, and triglyceride concentrations. High-density lipoprotein (HDL) cholesterol levels significantly increased only in the fenofibrate-treated patients (47.9 +/- 12.5 vs. 50.7 +/- 12.6 vs. 51.2 +/- 12.8 mg/dL, p < 0.01). Atorvastatin and fenofibrate treatment resulted in a significant reduction of serum uric acid levels (5.3 +/- 1.6 vs. 4.9 +/- 1.4 vs. 4.8 +/- 1.4 mg/dL, p < 0.0001 for atorvastatin; 5.6 +/- 1.6 vs. 4.3 +/- 1.4 vs. 4.4 +/- 1.4 mg/dL, p < 0.0001 for fenofibrate). Homocysteine levels were significantly increased only by fenofibrate (10.3 +/- 3.3 vs. 14.1 +/- 3.8 vs. 14.2 +/- 3.6 microU/L, p < 0.001) but did not change from baseline following statin treatment. Neither statins nor fenofibrate had any effect on serum vitamin B12 and folic acid levels. In contrast to fenofibrate, therapeutic dosages of atorvastatin and simvastatin have a neutral effect on serum homocysteine levels, which is in favor of their "cardioprotective" properties.
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PMID:Comparative effects of atorvastatin, simvastatin, and fenofibrate on serum homocysteine levels in patients with primary hyperlipidemia. 1295 39

About half of all deaths are due to cardiovascular disease and its complications. The economic burden on society and the healthcare system from cardiovascular disability, complications, and treatments is huge and getting larger in the rapidly aging populations of developed countries. As conventional risk factors fail to account for part of the cases, homocysteine, a "new" risk factor, is being viewed with mounting interest. Homocysteine is a sulfur-containing intermediate product in the normal metabolism of methionine, an essential amino acid. Folic acid, vitamin B12, and vitamin B6 deficiencies and reduced enzyme activities inhibit the breakdown of homocysteine, thus increasing the intracellular homocysteine concentration. Numerous retrospective and prospective studies have consistently found an independent relationship between mild hyperhomocysteinemia and cardiovascular disease or all-cause mortality. Starting at a plasma homocysteine concentration of approximately 10 micromol/l, the risk increase follows a linear dose-response relationship with no specific threshold level. Hyperhomocysteinemia as an independent risk factor for cardiovascular disease is thought to be responsible for about 10% of total risk. Elevated plasma homocysteine levels (>12 micromol/l; moderate hyperhomocysteinemia) are considered cytotoxic and are found in 5 to 10% of the general population and in up to 40% of patients with vascular disease. Additional risk factors (smoking, arterial hypertension, diabetes, and hyperlipidemia) may additively or, by interacting with homocysteine, synergistically (and hence over-proportionally) increase overall risk. Hyperhomocysteinemia is associated with alterations in vascular morphology, loss of endothelial anti-thrombotic function, and induction of a procoagulant environment. Most known forms of damage or injury are due to homocysteine-mediated oxidative stress. Especially when acting as direct or indirect antagonists of cofactors and enzyme activities, numerous agents, drugs, diseases, and lifestyle factors have an impact on homocysteine metabolism. Folic acid deficiency is considered the most common cause of hyperhomocysteinemia. An adequate intake of at least 400 microg of folate per day is difficult to maintain even with a balanced diet, and high-risk groups often find it impossible to meet these folate requirements. Based on the available evidence, there is an increasing call for the diagnosis and treatment of elevated homocysteine levels in high-risk individuals in general and patients with manifest vascular disease in particular. Subjects of both populations should first have a baseline homocysteine assay. Except where manifestations are already present, intervention, if any, should be guided by the severity of hyperhomocysteinemia. Consistent with other working parties and consensus groups, we recommend a target plasma homocysteine level of <10 micromol/l. Based on various calculation models, reduction of elevated plasma homocysteine concentrations may theoretically prevent up to 25% of cardiovascular events. Supplementation is inexpensive, potentially effective, and devoid of adverse effects and, therefore, has an exceptionally favorable benefit/risk ratio. The results of ongoing randomized controlled intervention trials must be available before screening for, and treatment of, hyperhomocysteinemia can be recommended for the apparently healthy general population.
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PMID:DACH-LIGA homocystein (german, austrian and swiss homocysteine society): consensus paper on the rational clinical use of homocysteine, folic acid and B-vitamins in cardiovascular and thrombotic diseases: guidelines and recommendations. 1465 16

Hyperlipidaemia is a major risk factor for cardiovascular disease. The drugs of choice for the treatment of hyperlipidaemia are either fibrates, in the case of hypertriglyceridaemia, or statins, in the case of hypercholesterolaemia. Recently, it has been shown that some of the most prescribed fibrates cause hyperhomocysteinemia, which itself has been recognised as a cardiovascular risk factor. In particular, fenofibrate and bezafibrate lead to a 20 - 40% elevation of plasma levels of the atherogenic amino acid homocysteine, thereby possibly counteracting the desired cardiovascular protection. The most likely mechanism for this increase is an alteration of creatine-creatinine metabolism and changes in methyl transfer. Gemfibrozil does not increase homocysteine. Statins have no effect on the plasma homocysteine concentration. The increase of plasma homocysteine after fenofibrate can be lowered by the concurrent administration of folic acid and vitamins B(12) and B(6). Thus, patients with hypertriglyceridaemia can either be concurrently treated with fenofibrate and vitamins or with gemfibrozil.
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PMID:The effect of fibrates and other lipid-lowering drugs on plasma homocysteine levels. 1500 16

The role of hyperhomocysteinemia as independent risk factor for stroke needs to be confirmed. The aims of our study were to assess (i) the association between risk of stroke and increasing values of plasma homocysteine and (ii) the interaction between mild hyperhomocysteinemia and conventional vascular risk factors. We studied 161 consecutive patients with first-ever ischemic stroke classified using TOAST criteria and 152 neurologically healthy controls. Homocysteine was measured using high performance liquid chromatography (HPLC). Homocysteinemia was elevated in all stroke subtypes: 13.0+/-2.5 micromol/l in patients with cardioembolic disease, 13.9+/-5.4 micromol/l in those with small vessel diseases, 15.5+/-6.8 micromol/l in cases of undetermined stroke, and 17.8+/-13.5 micromol/l in patients with large vessel disease. Mean homocysteinemia was 8.10 micromol/l (SD=2.5) in controls. The logistic regression analysis showed that important independent risk factors for ischemic stroke were hypertension (p<0.0001; OR= 3.205; 95% CI, 1.788-5.742), hyperhomocysteinemia (p<0.0001; OR=1.425; 95% CI, 1.300-1562) and hyperlipidemia (p=0.018; OR=2.243; 95% CI, 1.147-4.385). Hyperhomocyst(e)inemia is an independent risk factor for all stroke subtypes and should be routinely measured and treated in stroke patients.
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PMID:Mild hyperhomocysteinemia is a risk-factor in all etiological subtypes of stroke. 1506 Aug 10

Asymmetric dimethylarginine (ADMA), a guanidino-substituted analogue of L-arginine, is a potent endogenous competitive inhibitor of the endothelial nitric oxide synthase and therefore a potentially atherogenic amino acid. Hyperlipidemia and hyperhomocysteinemia have both been reported to be associated with elevated ADMA concentrations. Therefore, we investigated the influence of micronized fenofibrate (200 mg/day, 6 week treatment) on the L-arginine:ADMA ratio in 25 hypertriglyceridemic men. ADMA was neither associated to serum triglycerides, serum cholesterol, LDL-cholesterol or HDL-cholesterol or plasma total homocysteine at baseline. Treatment with fenofibrate did not alter plasma ADMA level, in contrast to serum triglycerides which were significantly lowered and plasma total homocysteine which was significantly increased. In addition, serum L-arginine levels significantly increased, leading to a higher L-arginine:ADMA ratio after treatment. The null effect of fenofibrate on plasma ADMA levels is in line with reported effects of other lipid-lowering agents (HMG-CoA-reductase inhibitors), but fenofibrate treatment elevated the plasma L-arginine:ADMA ratio, suggesting an improvement of endogenous NO formation and endothelial function. The results do not support the view that in vivo ADMA metabolism itself is directly influenced by cholesterol or homocysteine.
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PMID:Fenofibrate increases the L-arginine:ADMA ratio by increase of L-arginine concentration but has no effect on ADMA concentration. 1506 97

Alzheimer's disease is a devastating condition that is increasing in prevalence. No known prevention or cure exists for Alzheimer's disease. Cardiovascular risk factors are prevalent and increase in the elderly, and there have been conflicting reports of associations between modifiable cardiovascular risk factors and Alzheimer's disease. The mechanisms for these associations are uncertain, but they are likely to be the result of a combination of direct and cerebrovascular disease-related mechanisms. From this standpoint, diabetes and hyperinsulinemia seem to have the strongest evidence from laboratory, clinical, and epidemiologic studies. Studies have also indicated that hypertension, hyperlipidemia, hyperhomocysteinemia, and smoking are potentially important risk factors for Alzheimer's disease.
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PMID:Cardiovascular risk factors and Alzheimer's disease. 1519 99

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

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