Effet des polymorphismes des enzymes clés du métabolisme de l’homocystéine sur l’homocystéinémie et le risque coronarien chez une population tunisienne

Belkahla, Radhia; Omezzine, Asma; Kchok, Kaouther; Raîs, L.; M’Barek, Imane Ben; Rejeb, Jaleleddine Ben; Rejeb, N.; Slimane, N.; Nabli, Naoufel; Abdelaziz, Ahmed Ben; Boughzala, E.; Bouslama, Ali

doi:10.1016/j.ancard.2008.05.018

Cited by 14 publications

(6 citation statements)

References 31 publications

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“…Subsequent studies have revealed that this insertion is not a disease causing mutation but rather a common polymorphism whose frequency is largely different among human populations, with the variant allele being prevalent in African, European and North American populations [114-116]. Several studies report that the CBS 844ins68 polymorphism alone has not a relevant effect on tHcy concentrations [117,118]. Beyer and co-workers genotyped 206 AD patients and 186 age-matched controls, observing that the 844ins68 mutation was associated with AD risk in subjects aged 75 years or more at onset [119].…”

Section: One-carbon Metabolism In Alzheimer’s Diseasementioning

confidence: 99%

One-Carbon Metabolism and Alzheimers Disease: Focus on Epigenetics

Coppedè

2010

105

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Alzheimer’s disease (AD) represents the most common form of dementia in the elderly, characterized by progressive loss of memory and cognitive capacity severe enough to interfere with daily functioning and the quality of life. Rare, fully penetrant mutations in three genes (APP, PSEN1 and PSEN2) are responsible for familial forms of the disease. However, more than 90% of AD is sporadic, likely resulting from complex interactions between genetic and environmental factors. Increasing evidence supports a role for epigenetic modifications in AD pathogenesis. Folate metabolism, also known as one-carbon metabolism, is required for the production of S-adenosylmethionine (SAM), which is the major DNA methylating agent. AD individuals are characterized by decreased plasma folate values, as well as increased plasma homocysteine (Hcy) levels, and there is indication of impaired SAM levels in AD brains. Polymorphisms of genes participating in one-carbon metabolism have been associated with AD risk and/or with increased Hcy levels in AD individuals. Studies in rodents suggest that early life exposure to neurotoxicants or dietary restriction of folate and other B vitamins result in epigenetic modifications of AD related genes in the animal brains. Similarly, studies performed on human neuronal cell cultures revealed that folate and other B vitamins deprivation from the media resulted in epigenetic modification of the PSEN1 gene. There is also evidence of epigenetic modifications in the DNA extracted from blood and brains of AD subjects. Here I review one-carbon metabolism in AD, with emphasis on possible epigenetic consequences.

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Section: One-carbon Metabolism In Alzheimer’s Diseasementioning

confidence: 99%

One-Carbon Metabolism and Alzheimers Disease: Focus on Epigenetics

Coppedè

2010

105

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“…Les formes intermédiaires et sévères sont moins fréquentes, elles sont souvent causées par des mutations homozygotes aux niveaux des gènes des enzymes de métabolisation de l'hcy [12,15].…”

Section: Discussionunclassified

“…Le déficit en folate, en vitamine B12 et B6 qui sont des cofacteurs enzymatiques du métabolisme de l'hcy, contribuent également à l'hyperhomocystéinémie [11][12][13].…”

Section: Introductionunclassified

Étude de l’enzyme de conversion de l’angiotensine I et de l’hyperhomocystéinémie chez les coronariens tunisiens

Chalghoum

Noichri

Jaidane

et al. 2010

Immuno-analyse & Biologie Spécialisée

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“…Additionally, another study performed on Tunisian population with coronary artery-disease has shown that the effect of mutated MTHFR genotype was more pronounced on tHCY at low folatemia (<6.1 ng/ml) (51). Furthermore, in the current study, when cases were stratified according to expression of the T allele and folate ranges (<15.4 ng/ml and >15.4 ng/ml) and reanalyzed for the plasma tHCY, there was no significant increase in tHCY in the CT/TT genotype individuals.…”

Section: Discussionmentioning

confidence: 99%

Nutritional Factors, Homocysteine and C677T Polymorphism of the Methylenetetrahydrofolate Reductase Gene in Algerian Subjects with Cardiovascular Disease

Houcher¹,

Houcher²,

Touabti³

et al. 2012

Pteridines

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The C677T variant of methylenetetrahydrofolate reductase (MTHFR), a key enzyme in the remethylation of homocysteine (HCY) to methionine, is a frequent genetic cause of moderate hyperhomocysteinemia (HHCY) among individuals with cardiovascular disease (CVD), and particularly when combined with other factors such as hyperlipidaemia. However, in Algeria the influence of nutrient-gene interactions is not known. The aim of the present study was to explore the influence of age and gender, together with folate status, on the association between the C677T MTHFR polymorphism and plasma total HCY (tHCY) concentrations. This research was carried out as a prospective study on 98 patients hospitalized in the Cardiology Section, University of Sétif, Algeria. Mean age of participants was 57 y (range 20-96 y).The genetic analysis of the MTHFR C677T polymorphism was performed by real-time polymerase chain reaction (PCR) performed on Light Cycler in borosilicate capillaries with MTHFR 677CT polymorphism detection kit. The concentrations of tHCY, folic acid vitamin B 12 levels were determined using a competitive immunoassay on the IMMULITE 1000 Analyzers. Plasma total cholesterol, triglycerides, glucose, creatinine and urea concentrations were measured by colorimetric methods. Assays were conducted according to the manufacturers' instructions. Plasma tHCY was significantly higher in the patients with CVD, and HHCY was associated with the presence of mildly elevated serum urea and creatinine (p <0.05). MTHFR gene mutation does not seem to be associated with elevation of plasma tHCY in the studied patients and this lack of correlation could be influenced by the higher folate concentrations in our study. CVD patients with 677CT/TT genotypes had a higher concentration of total cholesterol than those with 677CC genotype (p <0.05). Although, the presence of 677T variant together with hypofolatemia (<15.4 ng/ml) had a more detrimental effect on the level of total cholesterol (p <0.05). Folatemia and vitamin B 12 were much higher in 677CC genotype compared to 677CT/TT genotype in CVD subjects without hyperlipidemia (p <0.05). However in patients with hyperlipidemia these values became lower also with 677CC genotype. In conclusion, hyperlipidemia affects the levels of plasma folate and vitamin B 12 concentrations independent of mutated MTHFR genotype. The effect of 677T variant on total cholesterol, folate and vitamin B 12 concentrations may relate to possible adverse effects of elevated tHCY on lipid profiles and on plasma folate and vitamin B 12 .

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Effet des polymorphismes des enzymes clés du métabolisme de l’homocystéine sur l’homocystéinémie et le risque coronarien chez une population tunisienne

Cited by 14 publications

References 31 publications

One-Carbon Metabolism and Alzheimers Disease: Focus on Epigenetics

One-Carbon Metabolism and Alzheimers Disease: Focus on Epigenetics

Étude de l’enzyme de conversion de l’angiotensine I et de l’hyperhomocystéinémie chez les coronariens tunisiens

Nutritional Factors, Homocysteine and C677T Polymorphism of the Methylenetetrahydrofolate Reductase Gene in Algerian Subjects with Cardiovascular Disease

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