RETOUR

HOMOCYSTEINE ET VIEILLISSEMENT

 

UN FACTEUR (MARQUEUR) DE RISQUE ?

 

1 LES METHYLATIONS

2 L'HOMOCYSTEINE

3 METABOLISME DE L'HOMOCYSTEINE

ROLE DES FOLATES ET DE LA VITAMINE B12 ET DE LA TMG

HOMOCYSTEINE ET TRANSULFURATION

HOMOCYSTÉINE / COMPLEX VIT B / MITOCHONDRIES

4 HOMOCYSTEINE, MORBIDITE ET VIEILLISSEMENT

5 CONCLUSIONS

6 COMPLÉMENTS 2006

7 ACTUALISATION 2009

 

 

1 LES METHYLATIONS

Un mécanisme ubiquitaire : DNA, enzymes, etc
Dégradation avec l’age
La méhylation est nécessairepour la transformation homocystéine > méthionine

 

RETOUR


2 L’HOMOCYSTEINE

Acide aminé toxique ; toujours présent

Découverte chez les enfants (Mc Cully 1960 - 1968) : l’impossibilité d’abaisser l’homocysteine > mortalité cardiaque précoce
Nombreux travaux depuis 1960 : homocystéine élevée = risque cardiovasculaire +++
RETOUR

 

3 METABOLISME DE L’HOMOCYSTEINE

ROLE DES FOLATES ET DE LA VITAMINE B12 ET DE LA TMG
Acide folique = donneur de méthyl
l’acide folique requiert la B12

TMG (trimethyl glycine) = donneur de méthyl

Supplémentation en folate + B12
> baisse de l’homocystéine


HOMOCYSTEINE ET TRANSULFURATION

Le phosphate de pyridoxal (vit B6) est nécessaire pour :
Homocystéine > Cystathionine > Cystéine


NB : pauvreté en B6 dans aliments conditionnés
        destruction B6 chez le fumeur
        diminution des taux avec pilule contraceptive


HOMOCYSTÉINE / COMPLEX VIT B / MITOCHONDRIES

Surproduction de radicaux libres
> Dysfonction Mitochondriale
> Mutagénèse somatique


 

RETOUR


4 HOMOCYSTEINE, MORBIDITE ET VIEILLISSEMENT

Nombreuses publications depuis moins de 5 ans

Une certitude pour les pathologies cardio-vasculaires
> Voir les pages suivantes résumant un certain nombre d’articles princeps


Pour d’autres situations pathologiques ?

Le plus argumenté actuellement : amplification de la neurodégénerescence et MALADIE D’ALZHEIMER

Des travaux de confirmation sont encore necessaires pour conclure






















RETOUR

 

5 CONCLUSIONS

Ce qui n’est plus contestable :
HOMOCYSTEINE = MARQUEUR DE RISQUE CV CHEZ LA PA


Ce qui demande encore confirmation :

HOMOCYSTEINE = TEMOIN BIOLOGIQUE DE VULNERABILITE,
en particulier au plan cérébral,
mais peut être pour d’autres tissus
(accroissement de l’attaque radicalaire)


Ce qui représente une retombée immédiate pratique

HOMOCYSTEINE = BON REFLET DE LA CARENCE
EN VITAMINES DU GROUPE B et en FOLATES ;
plus exactement reflet du défaut de biodisponibilité


Dosage plasmatique peu onéreux

 

RETOUR

 

AVRIL 2006 : HOMOCYSTEINE

La littérature re visitée




HCy et RISQUES CV : CONTROVERSES




Folate and vitamin B•12 and risk of fatal cardiovascular
disease: cohort study from Busselton, Western Australia
Joseph Hung, John P Beilby, Matthew W Knuiman, Mark Divitini
BMJ VOLUME 326 18 JANUARY 2003



Circulation. 2006 Mar 14;113(10):1335-43.
Improvement in stroke mortality in Canada and the United States, 1990 to 2002.
Yang Q, Botto LD, Erickson JD, Berry RJ, Sambell C, Johansen H, Friedman JM.
National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta,

BACKGROUND: In the United States and Canada, folic acid fortification of enriched grain products was fully implemented by 1998. The resulting population-wide reduction in blood homocysteine concentrations might be expected to reduce stroke mortality if high homocysteine levels are an independent risk factor for stroke.
METHODS AND RESULTS: In this population-based cohort study with quasi-experimental intervention, we used segmented log-linear regression to evaluate trends in stroke-related mortality before and after folic acid fortification in the United States and Canada and, as a comparison, during the same period in England and Wales, where fortification is not required. Average blood folate concentrations increased and homocysteine concentrations decreased in the United States after fortification. The ongoing decline in stroke mortality observed in the United States between 1990 and 1997 accelerated in 1998 to 2002 in nearly all population strata, with an overall change from -0.3% (95% CI, -0.7 to 0.08) to -2.9 (95% CI, -3.5 to -2.3) per year (P=0.0005). Sensitivity analyses indicate that changes in other major recognized risk factors are unlikely to account for the reduced number of stroke-related deaths in the United States. The fall in stroke mortality in Canada averaged -1.0% (95% CI, -1.4 to -0.6) per year from 1990 to 1997 and accelerated to -5.4% (95% CI, -6.0 to -4.7) per year in 1998 to 2002 (P< or =0.0001). In contrast, the decline in stroke mortality in England and Wales did not change significantly between 1990 and 2002.
CONCLUSIONS: The improvement in stroke mortality observed after folic acid fortification in the United States and Canada but not in England and Wales is consistent with the hypothesis that folic acid fortification helps to reduce deaths from stroke.



J Neurol Neurosurg Psychiatry. 2006 Apr 19;
Interaction of homocysteine and conventional predisposing factors on risk of ischemic stroke in young adults. Consistency of phenotype-disease analysis and genotype-disease analysis.
Pezzini A, Grassi M, Del Zotto E, Assanelli D, Archetti S, Negrini R, Caimi L, Padovani A.
Clinica Neurologica, Universita degli Studi di Brescia, Brescia, Italia, Italy.

BACKGROUND AND OBJECTIVES: Whether the association between mild hyperhomocysteinemia and ischemic stroke is the consequence of a predisposing genetic background or it is due to the confounding influence of established predisposing factors remains to be determined. Methoda: Plasma total homocysteine concentration(tHcy) and the distribution of the C677T genotypes of the methylenetetrahydrofolate reductase (MTHFR) gene were compared in 174 consecutive stroke patients aged <45 years and 155 controls. The effect of conventional risk factors on phenotype-disease and genotype-disease relation was analysed by two- and three-way interaction analysis and by the classification and regression trees (CART) model. RESULTS: tHcy levels were significantly higher in cases (11.9 micromol/l, range 2.0 to 94.0) compared with controls (9.8 micromol/l, range 4.7 to 49.6). An increased risk was also associated with the TT677 genotype (OR, 1.98; 95% CI, 1.04 to 3.78) and with the T allele (OR, 1.40; 95% CI, 1.03 to 1.92) of the MTHFR gene. A differential effect of Hcy on stroke risk was observed according to the distribution of environmental-behavioral risk factors, with stronger influence in the subcategory of hypertensive and smokers (OR, 24.8; 95% CI, 3.15 to 196). A comparable environmental-dependent TT677 MTHFR genotype-stroke association was observed in the genotype-disease analysis.
CONCLUSIONS: The analysis of specific subcategories of patients defined by the distribution of established risk factors indicates a consistency of phenotype-disease analysis and genotype-disease analysis. Our data indirectly support the assumption that the Hcy-stroke relation is unlikely due to a reverse-causality bias.



Neurol Sci. 2005 Dec;26(5):310-8.
Elevated plasma homocysteine in acute stroke was not associated with severity and outcome: stronger association with small artery disease.
Perini F, Galloni E, Bolgan I, Bader G, Ruffini R, Arzenton E, Alba S, Azzini C, Bartolomei L, Billo G, Bortolon F, Dudine P, Garofalo PG, L'Erario R, Morra M, Parisen P, Stenta G, Toso V.
Headache and Stroke Center, Department of Neurology, St. Bortolo Hospital, Ulss 6, Vicenza, Italy. f

Homocysteine increases in the acute phase of ischaemic stroke and from the acute to the convalescent phase, suggesting that hyper-homocysteinaemia may be a consequence rather than a causal factor. Therefore we measured homocysteine plasma levels in stroke patients in order to investigate possible correlations of homocysteine with stroke severity and clinical outcome. Further we looked for eventual differences in stroke subtypes. We prospectively studied plasma homocysteine levels in acute stroke patients admitted to the stroke unit of our department. Seven hundred and seventy-five ischaemic stroke patients, 39 cerebral haemorrhages and 421 healthy control subjects have been enrolled. Stroke severity and clinical outcome were measured with the Scandinavian Stroke Scale, the Rankin Scale and the Barthel Index. Stroke severity by linear stepwise regression analysis was not an independent determinant of plasma homocysteine levels. Homocysteine was not correlated with outcome measured by the Barthel Index. Mean plasma homocysteine of both ischaemic and haemorrhagic stroke was significantly higher than controls (p<0.05). Homocysteine had an adjusted odds ratios (OR) of 4.2 (95% CI 2.77-6.54) for ischaemic stroke and of 3.69 (95% CI 1.90-7.17) for haemorrhagic stroke. Compared with the lowest quartile, the upper quartile was associated with an adjusted OR of ischaemic stroke due to small artery disease of 17.4 (95% CI 6.8-44.3).
Homocysteine in the acute phase of stroke was not associated with stroke severity or outcome. Elevated plasma homocysteine in the acute phase of stroke was associated with both ischaemic and haemorrhagic stroke. Higher levels are associated with higher risk of small artery disease subtype of stroke.




Semin Neurol.
2006 Feb;26(1):24-32.
Homocyst(e)ine and stroke.
Furie KL, Kelly PJ.
Stroke Service, Massachusetts General Hospital, Harvard Medical School, Boston, 02114, USA.

Homocyst(e)ine elevation is associated with a two- to threefold fold increased risk of ischemic stroke. Although most commonly associated with large-artery atherosclerosis and venous thrombosis, hyperhomocysteinemia may contribute to stroke by other mechanisms as well. Levels of homocysteine are determined by genetic regulation of the enzymes involved in homocyst(e)ine metabolism and by levels of the vitamin cofactors (folate, B (6), and B (12)) associated with those reactions. Emerging evidence suggests that genetic variation within this pathway, such as the methyleneterahydrofolate reductase and cystathionine beta-synthase and nicotinamide N-methyltransferase genes, increases the risk of ischemic stroke. The introduction of grain folate fortification in 1998 has reduced homocyst(e)ine concentrations in the U.S. population. However, it is important to screen for vitamin B (12) deficiency and be cognizant that vitamin B (6) levels may be low in the elderly and in individuals with inflammatory disorders.
The Vitamin Intervention in Stroke Prevention study failed to prove that high-dose supplementation with folate, B (6), and B (12) reduced the risk of recurrent stroke or myocardial infarction at 2 years; however, there is an ongoing clinical trial evaluating the potential benefit of vitamin supplementation.


CMAJ. 2006 Feb 14;174(4):479-80.

Relative value of multiple plasma biomarkers as risk factors for coronary artery disease and death in an angiography cohort.
Lee KW, Hill JS, Walley KR, Frohlich JJ.
James Hogg iCAPTURE Centre of Cardiovascular and Pulmonary Research and the Healthy Heart Program, St. Paul's Hospital, Department of Pathology and Laboratory Medicine, and the University of British Columbia, Vancouver, BC.

BACKGROUND: Although elevated levels of C-reactive protein (CRP), interleukin (IL)-6, serum amyloid A protein (SAA) and total homocysteine (tHcy) have been associated with the increased likelihood of cardiovascular events, the relative or combined utility of these biomarkers in predicting atherosclerosis and death in an angiography cohort is unknown. METHODS: A cohort of 1117 consecutive patients (797 men and 320 women), referred to 2 Vancouver teaching hospitals for selective coronary angiography, was recruited between 1993 and 1995. Angiography results were obtained for 1019 patients. In 2004 we determined that of 1050 patients who could be traced, 231 had died, 95 of CAD-related causes. We compared the relative utility of baseline measurements of CRP, IL-6, SAA and tHcy as well as of lipids for predicting angiographic CAD and all-cause and CAD-related death. RESULTS: The risk of death increased across quartiles for CRP, IL-6, SAA and tHcy. When comparing the highest and lowest quartiles, the greatest hazard ratios were associated with IL-6 (2.57, 95% confidence interval [CI] 1.62-4.09) and tHcy (2.36, 95% CI 1.53-3.65). A Cox regression model containing all plasma biomarkers and traditional risk factors indicated that age, angiographic CAD and baseline plasma levels of IL-6 and tHcy remained independent predictors of CAD-related death, whereas age, sex, smoking, diabetes and apolipoprotein B levels were independent predictors of angiographic CAD. Kaplan-Meier survival curves indicated a utility in combining measures of CRP, SAA, IL-6 and tHcy for predicting risk of all-cause and CAD-related death.
INTERPRETATION: A comparison of elevated levels of CRP, IL-6, SAA and tHcy with traditional CAD risk factors indicated that IL-6 and tHcy were the strongest independent biomarkers for CAD-related death. Elevated levels of multiple biomarkers were associated with an increasing rate of all-cause and CAD-related death.


Mayo Clin Proc. 2006 Feb;81(2):177-82.
Association of plasma homocysteine with coronary artery calcification in different categories of coronary heart disease risk.
Kullo IJ, Li G, Bielak LF, Bailey KR, Sheedy PF 2nd, Peyser PA, Turner ST, Kardia SL.
Division of Cardiovascular Diseases, Mayo Clinic College of Medicine, 200 First St SW, Rochester, MN 55905, USA.

OBJECTIVE: To Investigate the association of plasma homocystelne with coronary artery calcification (CAC) in strata based on 10-year risk of coronary heart disease (CHD) in a cohort enriched in persons with hypertension. PARTICIPANTS AND METHODS: Fasting plasma homocystelne was measured by liquid chromatography electrospray tandem mass spectrometry. Coronary artery calcification was measured noninvasively by electron beam computed tomography and CAC score calculated using the method of Agatston et al. The 10-year CHD risk was calculated based on the Framingham risk score. The association of homocysteine with log-transformed CAC score was assessed in the pooled sample and within each risk stratum by linear regression after adjustment for conventional risk factors. RESULTS: In the 1071 participants studied, homocysteine was associated with CAC quantity (P = .01) after adjustment for CHD risk factors (age, male sex, total and high-density lipoproteln cholesterol, diabetes, history of smoking, body mass Index, and systolic blood pressure), serum creatinine, and statin and hypertension medication use. When the association was assessed in strata based on 10-year CHD risk, homocysteine was significantly (P = .003) associated with CAC quantity in participants at Intermediate 10-year risk of CHD (6%-20%) independent of other risk factors but not in those at lower risk or higher risk.
CONCLUSION: Plasma homocysteine is associated with quantity of CAC Independent of CHD risk factors. When studied in categories of 10-year CHD risk, the association was significant in participants at intermediate risk but not in those at low or high risk. Plasma homocysteine levels may have clinical utility as a marker of CHD risk in such individuals.



Neurol Res. 2006 Jan;28(1):25-30.
Serum level of homocysteine is correlated to carotid artery atherosclerosis in Chinese with ischemic stroke.
Wang H, Fan D, Zhang H, Fu Y, Zhang J, Shen Y.
Department of Neurology, Peking University Third Hospital, Beijing 100083, China.

OBJECTIVES: To investigate the relationship between serum level of homocysteine (Hcy) and carotid artery atheroscleosis (CAA). METHODS: Both sides of the common carotid artery and internal carotid artery in 126 Chinese patients with ischemic stroke were measured by B-mode ultrasound. The patients were divided into groups: normal, A, B, C and D according to the severity of CAAs. With fasting serum, Hcy as well as folate, vitamin B(12) and lipids were detected. The mean +/- SD age was 64 +/- 13 years (range 39-87 years). RESULTS: In a logistic regression model, the Hcy concentrations were associated with an elevated risk of CAAs independent of all traditional risk factors, and when CAAs became severer, the serum Hcy was higher. The levels of the normal group and A, B, C, D groups were 13.22 +/- 6.15 micromol/L, 16.29 +/- 9.81 micromol/l, 19.49 +/- 11.16 micromol/l, 27.21 +/- 17.47 micromol/l, and 24.14 +/- 8.64 micromol/l, respectively. Rank test showed a significant difference between normal and other groups (p<0.05). The levels of folate and vitamin B(12) were negatively correlated with the Hcy concentrations. Spearman correlation coefficient were -0.23 and -0.42 (p<0.05).
CONCLUSIONS: Hyperhomocysteinaemia is an independent risk factor of CAAs and the degree of CAAs is highly correlated with the level of Hcy in serum. The causes of hyperhomocysteinemia may be the result from the decrease in folate and vitamin B(12). Clinical trials are now required to evaluate the effect of treatment with these vitamins on the primary and secondary prevention of cerebral vascular diseases.
Vitamin B12, homocysteine and carotid plaque in the era of folic acid fortification of enriched cereal grain products
Julie Robertson, Francesco Iemolo, Sally P. Stabler, Robert H. Allen, J. David Spence CMAJ2005;172(12):1569-73



Vitamin B12, homocysteine and carotid plaque in the era of folic acid fortification of enriched cereal grain products
Julie Robertson, Francesco Iemolo, Sally P. Stabler, Robert H. Allen, J. David Spence CMAJ2005;172(12):1569-73



Vitamin B12, homocysteine and carotid plaque in the era of folic acid fortification of enriched cereal grain products
Julie Robertson, Francesco Iemolo, Sally P. Stabler, Robert H. Allen, J. David Spence CMAJ2005;172(12):1569-73


Relative value of multiple plasma biomarkers as risk factors for coronary artery disease and death in an angiography cohort
Kenny W.J. Lee, John S. Hill, Keith R. Walley, Jiri J. Frohlich CMAJ, fev2006, 174(4)

Background: Although elevated levels of C-reactive protein (CRP), interleukin (IL)-6, serum amyloid A protein (SAA) and total homocysteine (tHcy) have been associated with the increased likelihood of cardiovascular events, the relative or combined utility of these biomarkers in predicting atherosclerosis and death in an angiography cohort is unknown.
Methods: A cohort of 1117 consecutive patients (797 men and 320 women), referred to 2 Vancouver teaching hospitals for selective coronary angiography, was recruited between 1993 and 1995. Angiography results were obtained on 1019 patients. In 2004 we determined that of 1050 patients who could be traced, 231 had died, 95 of CAD-related causes. We compared the relative utility of baseline measurements of CRP, IL-6, SAA and tHcy as well as of lipids for predicting angiographic CAD and all-cause and CADrelated death.
Results: The risk of death increased across quartiles for CRP, IL-6, SAA and tHcy. When comparing the highest and lowest quartiles, the greatest hazard ratios were associated with IL-6 (2.57, 95% confidence interval [CI] 1.62&endash;4.09) and tHcy (2.36, 95% CI 1.53&endash;3.65). A Cox regression model containing all plasma biomarkers and traditional risk factors indicated that age, angiographic CAD and baseline plasma levels of IL-6 and tHcy remained independent predictors of CAD-related death, whereas age, sex, smoking, diabetes and apolipoprotein B levels were independent predictors of angiographic CAD. Kaplan&endash;Meier survival curves indicated a utility in combining measures of CRP, SAA, IL-6 and tHcy for predicting risk of all-cause and CADrelated death.
Interpretation: A comparison of elevated levels of CRP, IL-6, SAA and tHcy with traditional CAD risk factors indicated that IL-6 and tHcy were the strongest independent biomarkers for CAD-related death. Elevated levels of multiple biomarkers were associated with an increasing rate of all-cause and CAD-related death.

Abstract



HCy, STATUT VITAMINIQUE, ET PRÉVENTION DU RISQUE

Surg Today.
2006;36(4):327-31.
Hyperhomocysteinemia in patients with arterial occlusive disease.
Aksoy M, Basar Y, Salmayenli N, Ayalp K, Genc FA, Dilege S, Kayabali M, Baktiroglu S, Kurtoglu M.
Department of General Surgery, Istanbul University, Genel Cerrahi ABD, 34930, Capa, Istanbul, Turkey.

PURPOSE: Hyperhomocysteinemia (HHCA) is defined as an independent risk factor for atherothrombotic vascular disease; therefore, screening for HHCA is recommended. However, the incidence and characteristics of HHCA in patients with vascular disease remain unclear. We conducted this study in an attempt to resolve these issues. METHODS: This nonrandomized prospective study included 56 patients who were admitted with occlusive arterial disease (group I), and 39 control patients without occlusive arterial disease (group II). We recorded all the demographic data of both groups and collected blood samples for fasting homocysteine, vitamin B(12), and folic acid. All of the patients were followed up and the results were compared. RESULTS: The mean concentration of homocysteine was 12.69 +/- 3.82 micromol/l in group I and 10.46 +/- 5.08 micromol/l in group II (P = 0.00048). In group I, the mean homocysteine levels for patients aged >/=70 years and those aged <70 years were 13.74 +/- 3.02 and 11.55 +/- 4.15 micromol/l, respectively (P = 0.021). There was no significant difference in mortality between the patients with HHCA and those with normal homocysteine levels during follow-up.
CONCLUSION: The incidence of hyperhomocysteinemia was higher in the patients with occlusive vascular disease than in the control patients. More evidence of the association with vitamins B(12) and folate and the benefits of homocysteine-lowering therapy is needed since we found no relationship between these vitamins and homocysteine in this study.



Eur J Clin Nutr. 2006 Apr 19; [Epub ahead of print]
Kazakhstan: a folate-deficient area?
Akilzhanova A, Takamura N, Zhaojia Y, Aoyagi K, Karazhanova L, Yamashita S.

Objective:In the Republic of Kazakhstan, located in central Asia, the traditional diet consists mainly of meat, and vegetable intake tends to be deficient. This eating lifestyle may contribute to folate deficiency, which is closely linked to abnormal homocysteine (HCY) metabolism.Subjects and methods:In order to evaluate current folate status in the healthy Kazakh population, we screened serum folate and plasma HCY in 50 healthy Kazakh adults aged 20-65 years (KZH) and 60 healthy Japanese control subjects aged 27-65 years (JPN).Results:Serum levels of folate were significantly lower in KZH than in JPN (3.1 vs 10.0 ng/ml, P<0.01). Fifty of 61 (82.0%) subjects in KZH but none in JPN showed low concentrations of folate (<3.6 ng/ml). Plasma levels of HCY were significantly higher in KZH than in JPN (13.2 vs 7.8 nmol/ml, P<0.01).
Conclusions:Our findings strongly suggest that owing to the insufficient intake of vegetables, folate deficiency exists in Kazakhstan. Furthermore, hyperhomocysteinemia was observed in this group, probably owing to the secondary effects of folate deficiency.



Alcohol.
2005 Oct;37(2):73-7.
Alcohol consumption and plasma homocysteine.
Sakuta H, Suzuki T.

Department of Internal Medicine, Self-Defense Forces Central Hospital, 1-2-24 Ikejiri, Setagaya-ku, Tokyo
A few reports show that consumption of spirits and of wine correlate with elevated plasma total homocysteine (tHcy), which is associated with the risk of cardiovascular disease. We analyzed the relation between tHcy and current daily ethanol consumption cross-sectionally in middle-aged Japanese men (n=974, age 51-59 years). Plasma tHcy was positively associated with consumption of whiskey but not with consumption of shochu (Japanese spirits), sake, beer, or wine. Odds ratios of an increase in daily intake of 30ml ethanol (approximately 1 standard deviation) for hyperhomocysteinemia (>14.0mumol/l) were 2.58 (95% confidence interval, 1.29-5.14) for whiskey, 1.08 (0.78-1.50) for shochu, 0.99 (0.59-1.66) for sake, 0.98 (0.58-1.63) for beer, and 1.70 (0.31-9.50) for wine in a multivariate logistic regression analysis adjusted for the daily number of cigarettes smoked, physical activity, vegetable consumption, and serum creatinine levels. After inclusion of plasma folate and vitamin B(12) in the multivariate analysis model, the association between whiskey ethanol consumption and hyperhomocysteinemia remained significant with odds ratio of 2.79 (1.36-5.72).
These results suggest that whiskey consumption correlates with hyperhomocysteinemia independently of plasma folate or vitamin B(12) or lifestyle factors in the population studied.




Am J Clin Nutr. 2006 Jan;83(1):52-8.
A daily intake of approximately 6 microg vitamin B-12 appears to saturate all the vitamin B-12-related variables in Danish postmenopausal women.
Bor MV, Lydeking-Olsen E, Moller J, Nexo E.
Department of Clinical Biochemistry, Norrebrogade Section, Aarhus Hospital, Aarhus, Denmark.

BACKGROUND: Recommended daily intakes of vitamin B-12 vary between 2 and 6 microg. OBJECTIVE: The objective was to examine the associations between vitamin B-12 intake and markers of vitamin B-12 deficiency. DESIGN: We studied 98 Danish postmenopausal women aged 41-75 y. Serum cobalamin, transcobalamin (TC) saturated with vitamin B-12 (holo-TC), TC saturation (holo-TC/total TC), methylmalonic acid (MMA), and total homocysteine (tHcy) were measured to assess vitamin B-12 status. Dietary intakes of vitamin B-12 were determined from 7-d weighed food records. Gastric pH measurement and the alkali-challenge test were performed with the use of Heidelberg radiotelemetric capsules. RESULTS: The total intake of vitamin B-12 ranged from 1.2 to 23.9 microg/d. All vitamin B-12-related variables, except gastric pH, correlated significantly with total vitamin B-12 intake. Those taking supplements (54%) had higher circulating concentrations of cobalamin and TC saturation and lower concentrations of MMA and tHcy than did those not taking supplements. All subjects were divided into quintiles according to their total vitamin B-12 intake. For all the variables analyzed, the curves appeared to level off at a daily vitamin B-12 intake of approximately 6 microg; the median (and 25th-75th percentiles) for cobalamin was 380 (270-480) pmol/L, for holo-TC was 119 (92-162) pmol/L, for MMA was 0.12 (0.14-0.17) micromol/L, and for tHcy was 9.75 (8.3-11.40) micromol/L (n = 58).
CONCLUSION: A daily vitamin B-12 intake of 6 microg appeared to be sufficient to correct all the vitamin B-12-related variables measured in the postmenopausal Danish women in this study.



Nutr J.
2006 Feb 10;5:5. Dietary and other lifestyle correlates of serum folate concentrations in a healthy adult population in Crete, Greece: a cross-sectional study. Hatzis CM, Bertsias GK, Linardakis M, Scott JM, Kafatos AG.
Preventive Medicine and Nutrition Clinic, Faculty of Medicine, University of Crete, P,O,
BACKGROUND: Folate has emerged as a key nutrient for optimising health. Impaired folate status has been identified as a risk factor for cardiovascular disease, various types of cancers, and neurocognitive disorders. The study aimed at examining the distribution and determinants of serum folate concentrations in a healthy adult population in Crete, Greece. METHODS: A cross-sectional sample of 486 healthy adults (250 men, 236 women) aged 39 +/- 14 years, personnel of the Medical School and the University Hospital of Crete in Greece, was examined. Serum folate and vitamin B12 concentrations were measured by microbiological assay, and total homocysteine was determined fluorometrically and by high-pressure liquid chromatography. Lifestyle questionnaires were completed, and nutrient intakes and food consumption were assessed by 24-h dietary recalls. Multivariate analyses were performed using SPSS v10.1. RESULTS: The geometric mean (95% confidence interval) concentrations of serum folate were 15.6 micromol/l (14.6-16.8) in men and 19.2 micromol/l (17.9-20.7) in women (p < 0.001). Inadequate folate levels (<or=7 nmol/l) were present in 6.8% of men and 2.1% of women (p < 0.001). Approximately 76% of men and 87% of women did not meet the reference dietary intake for folate (400 microg/day). Serum folate was inversely related to total homocysteine levels (p < 0.001). Increased tobacco and coffee consumption were associated with lower folate concentrations (p < 0.05 for both) but these associations disappeared after controlling for nutrient intakes. In multivariate analysis, intakes of MUFA, fibre, calcium, magnesium, folate, and vitamins A, E, C, B1, and B6 were positively associated with serum folate. Consumption of potatoes, legumes, fruits, and vegetables were favourably related to the serum folate status.
CONCLUSION: Serum folate concentrations were associated with various demographic, lifestyle and dietary factors in healthy Cretan adults. Large-scale epidemiological studies should be conducted within the general Greek adult population to assess the prevalence of impaired folate status and further examine associations with dietary patterns and chronic disease risk. Considering the importance of folate in health maintenance, it is important to increase the public's awareness of modifiable lifestyle patterns and diet and tobacco use in particular, which may be associated with improved folate status.


HCy / MTA / autres patho neuro degénératives

Lancet Neurol. 2006 Mar;5(3):198-9.
Association between CSF biomarkers and incipient Alzheimer's disease in patients with mild cognitive impairment: a follow-up study.
Hansson O, Zetterberg H, Buchhave P, Londos E, Blennow K, Minthon L.
Clinical Memory Research Unit, Department of Clinical Sciences Malmo, Lund University, Sweden.

BACKGROUND: Disease-modifying treatment strategies for Alzheimer's disease have led to an urgent need for biomarkers to identify the disease at a very early stage. Here, we assess the association between CSF biomarkers and incipient Alzheimer's in patients with mild cognitive impairment (MCI). METHODS: From a series of 180 consecutive patients with MCI, we assessed 137 who underwent successful lumbar puncture at baseline. Patients at risk of developing dementia were followed clinically for 4-6 years. Additionally, 39 healthy individuals, cognitively stable over 3 years, served as controls. We analysed CSF concentrations of beta amyloid(1-42) (Abeta42), total tau (T-tau), and phosphorylated tau (P-tau181) using Luminex xMAP technology. FINDINGS: During follow-up, 57 (42%) patients with MCI developed Alzheimer's disease, 21 (15%) developed other forms of dementia, and 56 (41%) remained cognitively stable for 5.2 years (range 4.0-6.8). A combination of CSF T-tau and Abeta42 at baseline yielded a sensitivity of 95% and a specificity of 83% for detection of incipient AD in patients with MCI. The relative risk of progression to Alzheimer's disease was substantially increased in patients with MCI who had pathological concentrations of T-tau and Abeta42 at baseline (hazard ratio 17.7, p<0.0001). The association between pathological CSF and progression to Alzheimer's disease was much stronger than, and independent of, established risk factors including age, sex, education, APOE genotype, and plasma homocysteine. The combination of T-tau and Abeta42/P-tau181 ratio yielded closely similar results (sensitivity 95%, specificity 87%, hazard ratio 19.8).
INTERPRETATION: Concentrations of T-tau, P-tau181, and Abeta42 in CSF are strongly associated with future development of Alzheimer's disease in patients wit




Dement Geriatr Cogn Disord. 2006;21(3):148-54. Epub 2006 Jan 2.
Plasma homocysteine and vascular disease in psychogeriatric patients.
Nilsson K, Gustafson L, Hultberg B.
Department of Psychogeriatrics, Clinical Science, Lund University Hospital, Lund, Sweden.

BACKGROUND: There is a high frequency (40-50%) of elevated plasma total homocysteine (tHcy) concentrations in elderly patients with mental disorders, and patients with a history of vascular disease exhibit significantly higher plasma tHcy concentration than patients without vascular disease. METHOD: The main objective of the present study was to further investigate the association between plasma tHcy concentration and vascular disease in psychogeriatric patients. We have therefore investigated 304 psychogeriatric patients and determined plasma tHcy and its most important determinants (folate and cobalamin status and renal function), and the natriuretic peptide N-terminal-pro brain natriuretic peptide (NT-proBNP). The patients were classified into several groups of vascular disease according to the findings of brain imaging and presence of a history/symptoms indicating manifest occlusive arteriosclerotic vascular disease. RESULTS: Plasma tHcy concentration is associated with the presence of vascular disease in psychogeriatric patients. The presence of vascular disease is also associated with higher age, higher serum NT-proBNP, renal impairment and lower serum folate concentration than in patients without vascular disease. The significant association between plasma tHcy concentration and vascular disease remained after correction for age and for cystatin C differences between the groups of patients without and with vascular disease. In the present population with only 16% of the patients showing elevated plasma tHcy, renal function was a more important determinant for plasma tHcy concentration than folate status.
CONCLUSION: Plasma tHcy concentration is associated with vascular disease. In the present population of psychogeriatric patients renal function is associated with vascular disease and elevated plasma tHcy concentration. Thus, the association between plasma tHcy concentration and vascular disease might partially be explained by impairment of renal function.




J Neurol Neurosurg Psychiatry. 2006 Feb;77(2):189-92.
Plasma homocysteine levels in multiple sclerosis.
Ramsaransing GS, Fokkema MR, Teelken A, Arutjunyan AV, Koch M, De Keyser J.
Department of Neurology, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, Netherlands.

BACKGROUND: There is evidence that homocysteine contributes to various neurodegenerative disorders, and elevated plasma homocysteine levels have been observed in patients with multiple sclerosis (MS). OBJECTIVE: To investigate if and why plasma homocysteine levels are increased in MS, and whether they play a role in the disease course. METHODS: We compared plasma levels of homocysteine in 88 patients with MS and 57 healthy controls. In the MS group, 28 had a benign course, 37 were secondary progressive, and 23 primary progressive. To explore the underlying mechanisms, we measured serum levels of vitamins B6 and B12, folate, interleukin (IL)-12, tumour necrosis factor (TNF)-alpha, leukocyte nitric oxide production, and plasma diene conjugate levels (measure of oxidative stress). RESULTS: Mean (SD) plasma homocysteine concentration was higher in patients (13.8 (4.9) micromol/l) than in controls (10.1 (2.5) micromol/l; p<0.0001). However, there were no significant differences in homocysteine levels between the three clinical subgroups of MS. Serum concentrations of vitamin B6, vitamin B12, and folate were not different between patients with MS and controls. In the MS group, there were no correlations between plasma homocysteine levels and the serum concentrations of IL-12 or TNF-alpha, leukocyte nitric oxide production, or plasma diene conjugate levels.
CONCLUSIONS: Elevated plasma homocysteine occurs in both benign and progressive disease courses of MS, and seems unrelated to immune activation, oxidative stress, or a deficiency in vitamin B6, vitamin B12, or folate.



DIVERS...

INFLAMMATION et Hcy

PATHO OCULAIRE et Hcy

Glaucome et Hcy :
DMLA et Hcy
Thrombose veine centrale rétine

DENSITÉ OSSEUSE et Hcy

ANTIOXYDANTS et DOMMAGES RELIÉS À Hcy



 

INFLAMMATION et Hcy


Scand J Clin Lab Invest.
2006;66(1):45-54.
Increased levels of C-reactive protein and interleukin-6 in hyperhomocysteinemic subjects.
Holven KB, Aukrust P, Retterstol K, Hagve TA, Morkrid L, Ose L, Nenseter MS.

OBJECTIVE: Elevated plasma homocysteine concentration is considered to be an independent risk factor for cardiovascular disease. However, the mechanisms by which hyperhomocysteinemia are related to vascular disease are unclear. High-sensitivity C-reactive protein (CRP), a marker of inflammation, has been reported to be an independent predictor of future myocardial infarction among clinically healthy individuals. Interleukin (IL)-6 is a regulator of CRP and has a key role in initiation of inflammation. The aim of this study was to investigate whether individuals with increased plasma homocysteine concentrations have altered levels of serum CRP and IL-6.
MATERIAL AND METHODS: Serum concentrations of CRP and IL-6 were measured in 39 individuals with hyperhomocysteinemia and in 39 control subjects matched for gender, age and body mass index (BMI). In addition, the inflammatory effect of IL-6 on peripheral blood mononuclear cells was measured. RESULTS: Compared to controls, hyperhomocysteinemic subjects have elevated serum levels of CRP and IL-6 (p < or =0.001 and p < 0.005, respectively). Importantly, this raised level of IL-6 was also seen in hyperhomocysteinemic individuals without accompanying hypercholesterolemia or cardiovascular disease. IL-6 increased the release of monocyte chemoattractant protein-1 from peripheral blood mononuclear cells, with particularly enhancing effects in cells from patients with hyperhomocysteinemia. CONCLUSIONS: These data suggest that enhanced inflammation may be associated with homocysteine-related cardiovascular disease, possibly involving IL-6-related mechanisms.



PATHO OCULAIRE et Hcy


Glaucome et Hcy :

BMC Ophthalmol. 2006 Feb 23;6:6.
Serum homocysteine, vitamin B 12 and folic acid levels in different types of glaucoma.
Cumurcu T, Sahin S, Aydin E.

BACKGROUND: This study was performed to compare levels of serum homocysteine (Hcy), vitamin B12 and folic acid in patients with primary open-angle glaucoma (POAG), pseudoexfoliative glaucoma (PEXG), normotensive glaucoma (NTG) and healthy controls. METHODS: Twenty-five patients with POAG, 24 with PEXG, and 18 with NTG, along with 19 control healthy subjects were included this prospective study. Levels of serum Hcy were measured using immunoassay, and those of serum vitamin B12 and folic acid were measured using competitive chemiluminescent enzyme immunoassay. RESULTS: The mean Hcy concentration in the PEXG group was significantly higher (P < 0.001) as compared to the other groups. There were no significant differences with respect to the mean Hcy concentrations among other groups (P > 0.05). There were no statistical differences in serum vitamin B12 levels among POAG, PEXG, NTG and control subjects (P > 0.05).The mean serum folic acid level was significantly lower in the subjects with PEXG (P < 0.009). However, the mean folic acid concentrations among the other groups did not differ significantly (P > 0.05).
CONCLUSION: Elevated levels of Hcy in PEXG may explain the role of endothelial dysfunction among patients with PEXG.



DMLA et Hcy

Am J Ophthalmol. 2006 Jan;141(1):201-3.
Evaluation of plasma homocysteine and risk of age-related macular degeneration.
Seddon JM, Gensler G, Klein ML, Milton RC.

PURPOSE: To assess the relationship between plasma levels of homocysteine and age-related macular degeneration (AMD). DESIGN: Cross-sectional, case-control study. METHODS: Fasting plasma homocysteine levels were measured at two centers in 934 individuals who were participating in an ancillary study of the Age-Related Eye Disease Study. There were 547 cases and 387 control subjects, who were determined by fundus photography. Conditional logistic regression analyses were conducted to assess the association of homocysteine with AMD. RESULTS: Median values of homocysteine were higher among advanced AMD cases (9.51 mmol/l) compared with persons with no AMD (8.81 mmol/l; P = .01). Values of >12 mmol/l vs < or =12 mmol/l were also associated with an increased risk of AMD (P = .023), when controlled for other covariates.
CONCLUSION: Results are consistent with a possible association between higher homocysteine levels and AMD. Homocysteine may be a modifiable risk factor for AMD.



Thrombose veine centrale rétine

Retina.
2006 Jan;26(1):65-70.
Moderate hyperhomocysteinemia and early-onset central retinal vein occlusion.
Lattanzio R, Sampietro F, Ramoni A, Fattorini A, Brancato R, D'Angelo A.

Department of Ophthalmology & Visual Sciences, University Hospital S. Raffaele, Milan, Italy. lattanzio.rosangela@hsr.it

PURPOSE: To evaluate the prevalence of moderate fasting hyperhomocysteinemia (HHcy) and postmethionine load (PML) HHcy among patients with early-onset central retinal vein occlusion (CRVO). METHODS: The prevalence of fasting HHcy and that of PML HHcy were evaluated in a consecutive series of 58 patients with CRVO who were younger than 56 years of age (mean age, 40.3 years) and in 103 controls (mean age, 39.6 years). Plasma folate, vitamin B12, and pyridoxal-5'-phosphate (PLP) levels were measured in 42 patients and 67 controls. RESULTS: Mantel-Haenszel odds ratios for CRVO patients were 3.00 (95% confidence interval [CI], 0.83-10.8) for fasting HHcy, 3.50 (95% CI, 1.07-11.4) for PML HHcy, and 3.00 (1.18-7.6) for fasting HHcy and PML HHcy in subjects with normal fasting total homocysteine (tHcy) levels. Moderate HHcy was associated with reduced plasma levels of folate and PLP (P < or = 0.04). There was no significant dependence of fasting and PML tHcy levels on any traditional risk factor evaluated.
CONCLUSIONS: Moderate HHcy is an independent risk factor for early-onset CRVO.



DENSITÉ OSSEUSE et Hcy


Arch Intern Med.
2006 Jan 9;166(1):88-94.
Plasma total homocysteine level and bone mineral density: the Hordaland Homocysteine Study.
Gjesdal CG, Vollset SE, Ueland PM, Refsum H, Drevon CA, Gjessing HK, Tell GS.

BACKGROUND: Plasma total homocysteine (tHcy) has been associated with hip fracture but not directly with bone mineral density (BMD). We examined the association of hip BMD with levels of plasma tHcy, folate, and vitamin B12 and the methylenetetrahydrofolate reductase (MTHFR) 677C-->T and 1298A-->C polymorphisms. METHODS: Bone mineral density was measured between 1997 and 2000 in 2268 men and 3070 women, aged 47 to 50 and 71 to 75 years, from the Hordaland Homocysteine Study cohort. Low BMD was defined as BMD in the lowest quintile for each sex and age group. Linear, logistic, and generalized additive regression models were used. RESULTS: Plasma levels of tHcy were inversely related to BMD among middle-aged and elderly women (P<.001) but not among men. The multiple adjusted odds ratio for low BMD among subjects with high (>or=15 micromol/L [>or=2.02 mg/L]) compared with low (<9 micromol/L [<1.22 mg/L]) tHcy level was 1.96 (95% confidence interval, 1.40-2.75) for women and was not significant for men. Additional adjustments for plasma folate level or intake of calcium and vitamin D did not substantially alter the results. Plasma folate level was associated with BMD in women only. We observed no association between BMD and vitamin B12 level or the MTHFR polymorphisms.
CONCLUSIONS: Elevated tHcy and low folate levels were associated with reduced BMD in women but not in men. These findings suggest that tHcy may be a potential modifiable risk factor for osteoporosis in women.


ANTIOXYDANTS et DOMMAGES RELIÉS À Hcy


J Nutr. 2006 Mar;136(3 Suppl):810S-812S.
Garlic reduces dementia and heart-disease risk.
Borek C.
Department of Public Health and Family Medicine, Tufts University School of Medicine, Boston, MA 02111, USA.

Risk factors for cardiovascular disease, including high cholesterol, high homocysteine, hypertension and inflammation, increase the risk of dementia, including its most common form, Alzheimer's disease (AD). High cholesterol is also associated with elevated beta-amyloid (Abeta), the hallmark of AD. Oxidative damage is a major factor in cardiovascular disease and dementia, diseases whose risk increases with age. Garlic, extracted and aged to form antioxidant-rich aged garlic extract (AGE or Kyolic), may help reduce the risk of these diseases. AGE scavenges oxidants, increases superoxide dismutase, catalase, glutathione peroxidase, and glutathione levels, and inhibits lipid peroxidation and inflammatory prostaglandins. AGE reduces cholesterol synthesis by inhibiting 3-hydroxy-3-methylglutaryl-CoA reductase and is additive with statins in its action. Inhibition of cholesterol, LDL oxidation, and platelet aggregation by AGE, inhibits arterial plaque formation; AGE decreases homocysteine, lowers blood pressure, and increases microcirculation, which is important in diabetes, where microvascular changes increase heart disease and dementia risks. AGE also may help prevent cognitive decline by protecting neurons from Abeta neurotoxicity and apoptosis, thereby preventing ischemia- or reperfusion-related neuronal death and improving learning and memory retention. Although additional observations are warranted in humans, compelling evidence supports the beneficial health effects attributed to AGE in helping prevent cardiovascular and cerebrovascular diseases and lowering the risk of dementia and AD.



J Nutr. 2006 Mar;136(3 Suppl):755S-758S.
Aged garlic extract inhibits homocysteine-induced CD36 expression and foam cell formation in human macrophages.
Ide N, Keller C, Weiss N.

Elevated plasma homocysteine (Hcy) levels have been recognized as an independent risk factor for atherosclerotic vascular disease. During formation of early atherosclerotic lesions, expression of CD36, a class B scavenger receptor on macrophages, is crucially involved in the uptake of oxidized low-density lipoprotein (OxLDL) and foam-cell formation. We therefore determined the effects of Hcy on CD36 expression and foam cell formation in human monocytes/macrophages (THP-1) using flow cytometry, and the effects of aged garlic extract (AGE) on this process. Incubation of THP-1 cells with Hcy (200 micromol/L) for 72 h in the presence of phorbol 12-myristate 13-acetate (PMA) (10 nmol/L) caused a 37.8+/-5.2% increase in CD36 expression compared with PMA-stimulated cells without Hcy (P<0.01). Coincubation with AGE (5 g/L) significantly suppressed CD36 expression by 61.8+/-13.9%, compared with control conditions, and by 48.6+/-9.0% compared with Hcy-incubated cells (P<0.01). THP-1 cells in the presence of PMA (10 nmol/L) were incubated with Hcy or AGE for 72 h followed by incubation with 1,1'-dioctadecyl-3,3,3'3'-tetra-methylindocyanide percholorate (DiI)-labeled OxLDL for 3 h, and fluorescence intensity was measured by flow cytometry. AGE also inhibited DiI-labeled OxLDL uptake into PMA-stimulated THP-1 cells by 85.6+/-2.8% (P<0.01), but Hcy had no effects on it. Our data indicate that AGE inhibits CD36 expression and OxLDL uptake in macrophages and suggest that the extract could modulate the formation of early atherosclerotic lesions.



J Nutr. 2006 Mar;136(3 Suppl):750S-754S.
Aged garlic extract improves homocysteine-induced endothelial dysfunction in macro- and microcirculation.
Weiss N, Ide N, Abahji T, Nill L, Keller C, Hoffmann U.
Department of Metabolic Diseases, Medical Policlinic, City Campus, University of Munich Medical Center, Munich,

Endothelial dysfunction caused by increases in vascular oxidant stress that decrease bioavailable nitric oxide (NO) plays a critical role in the vascular pathobiology of hyperhomocysteinemia. Boosting cellular glutathione levels or increasing the activity of cellular glutathione peroxidase can compensate for homocysteine's effects on endothelial function. Aged garlic extract (AGE) contains water- and oil-soluble sulfur compounds that modify the intracellular thiol and redox state, minimize intracellular oxidant stress, and stimulate NO generation in endothelial cells and animals. We performed a placebo-controlled, blinded, crossover trial to examine whether AGE reduces macro- and microvascular endothelial dysfunction during acute hyperhomocysteinemia induced by an oral methionine challenge in healthy subjects. Acute hyperhomocysteinemia leads to a significant decrease in flow-mediated vasodilation of the brachial artery as determined by vascular ultrasound, indicative of macrovascular endothelial dysfunction. In addition, acute hyperhomocysteinemia leads to a decrease in acetylcholine-stimulated skin perfusion as measured by laser-Doppler flowmetry. This indicates microvascular endothelial dysfunction, which is presumably a result of impairment of the endothelium-derived hyperpolarizing factor pathway. Pretreatment with AGE for 6 wk significantly diminished the adverse effects of acute hyperhomocysteinemia in both vascular territories. We conclude that AGE may at least partly prevent a decrease in bioavailable NO and endothelium-derived hyperpolarizing factor during acute hyperhomocysteinemia. This pilot study warrants further investigations on the effects of AGE on endothelial dysfunction in patients with other cardiovascular risk factors or established vascular disease and on the clinical outcome of patients with cardiovascular disease.



J Nutr. 2006 Mar;136(3 Suppl):745S-749S.
Homocysteine-lowering action is another potential cardiovascular protective factor of aged garlic extract.
Yeh YY, Yeh SM.

Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16803, USA.
We investigated hypohomocysteinemic action as a cardiovascular protective property of aged garlic extract (AGE). Hyperhomocysteinemia was induced in rats by feeding folate-depleted diets. Plasma folate concentrations of 5, 24, and 202 nmol/L were detected in rats fed a folate-deficient L-amino acid diet containing succinyl sulfathiazole, an AIN-93G folate-deficient diet, and an AIN-93G folate-sufficient diet, respectively. Plasma concentrations of total homocysteine were elevated to the highest level (32 micromol/L) by severe folate deficiency and to a moderate level (9 micromol/L) by mild folate deficiency, compared with the lowest level of (5 micromol/L), noted for the folate-sufficient group. The addition of AGE to the severely folate-deficient diet decreased plasma total homocysteine concentration by 30%. Hyperhomocysteinemia caused by mild folate deficiency remained unaltered by AGE supplementation. The reduction in total homocysteine of the severely folate-deficient rats was accompanied by a proportional decrease in protein-bound and free homocysteine, resulting in an unchanged protein-bound:free homocysteine ratio. AGE added to the diet did not alter plasma concentrations of other aminothiol compounds: cysteine, glutathione, and cysteinylglycine. These data, together with increased S-adenosylmethionine and decreased S-adenosylhomocysteine concentrations in the liver, suggest that the hypohomocysteinemic effect of AGE most likely stems from impaired remethylation of homocysteine to methionine and enhanced transsulfuration of homocysteine to cystathionine.
More importantly, in addition to its cholesterol-lowering potential, blood pressure-lowering effect, and antioxidant property, a hypohomocysteinemic action may be another important cardiovascular protective factor of AGE.

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COMPLÉMENTS 2009



































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CONCLUSIONS


Ce qui n'est plus contestable :
HOMOCYSTEINE = MARQUEUR DE RISQUE CV CHEZ LA PA
Valeur individuelle ? index composite (Il6 + HCy + CRP+...) ?

Ce qui demande encore confirmation :
HOMOCYSTEINE = TEMOIN BIOLOGIQUE DE VULNERABILITE,
en particulier au plan cérébral, mais peut être pour d'autres tissus (accroissement de l'attaque radicalaire)

Ce qui représente une retombée immédiate pratique
HOMOCYSTEINE = BON REFLET DE LA CARENCE EN VITAMINES DU
GROUPE B et en FOLATES ;
plus exactement reflet du défaut de biodisponibilité
Dosage plasmatique peu onéreux mais difficile à proposer


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