Higher Plasma Homocysteine Concentrations Research Articles

Plasma Homocysteine in Patients with Coronary and Carotid Artery Disease: A Case Control Study.

Homocystein (Hcy) is an amino acid and elevated plasma cause endothelial damage, followed with inflammation in the blood vessels and its progression in atherosclerosis. We aimed to evaluate the correlation between cardiovascular disease and serum homocysteine levels.. We performed a case control analysis of 212 patients, either for cardiovascular risk stratification or for invasive diagnostics and treatment of cardiovascular ischemic disease (CAD). Patients were divided into 4 groups: Group 1. Patients with low risk for CAD, with no symptoms of CAD and total of 10 years risk <10%. Group 2. High-risk patients with no symptoms of CAD, but 10 years total CAD risk of >20%. Group 3. Patients with symptomatic CAD, where angiography was performed and >50% occlusion of at least one coronary vessel was found. Group 4. Patients with carotid artery disease and documented CAD. Group 1 consists of 56 subjects, of whom 33 (60%) males and 22 (40%) females. Their mean age was 52.18±8.07 years and their average CAD risk was 5. Group 2 included 60 patients, with average CAD risk of 23.73. There was a statistically significant difference between plasma homocysteine levels between the control and high CAD risk group, as well as between those with CAD and both CAD and CARD (p=0.001). In the high-risk subjects group, the level of homocysteine correlates albeit weak with the total CAD risk (p=0.04). Homocysteine levels correlate with the WBC count (p=0.02). In the subgroup of smokers with high CAD risk, homocysteine correlates with age, total CAD risk, total cholesterol, BUN (define BUN) and creatinine. Group 3 consisted of 49 subjects with manifested and angiographically proven CAD, out of whom 80% were males and 20% females, mean age 56.06±9.7 years, with average 2 coronary vessels affected. There were significantly higher homocysteine plasma levels between the control group and the group with manifested CAD (p=0.008).There is no significant difference of homocysteine plasma levels between the high risk group and the group with manifested coronary artery disease (15.03□mol/l vs. 16.38□mol/l). In this group, plasma levels of homocysteine correlate only with the highest level of vessel stenosis (>95%) with (p=0.04). The study population in group 4 showed a mean of IMT 0.9 +..09 mm and mean Hcy plasma levels of 21 + 11 µmol/L. From the evaluated patients with CAD, 82.9% of patients had elevated level of Hcy. From those, one showed elevated Hcy, 79.4 % had hypertension, 58.9 % had hyperlipidemia, 28.2% had diabetes mellitus as additional risk factors for atherosclerosis. 76.9 % of the patients had increased intima-media thickness; in 58.9 % plaques were detected, while 23 % of the patients had significant stenosis: 10.2 % with intermediate-grade stenosis (50-69%) and 12.8 % with high-grade stenosis (70-99 %). 17.1 % of the patients had normal level of Hcy, and in those ones 62.5 % only had increased IMT. We found linear correlation between IMT and HCy levels (r 0.7, p 0.05). Case control analysis showed significant higher level of Hcy in the group with CAD and carotid artery disease vs. CAD group (p 0.001). High plasma homocysteine concentrations are associated with high risk for vascular disease and consequently CAD itself and carotid artery disease, as well, proving its likely role in the development of atherosclerosis on inflammatory and metabolic levels.

Supplementation with dairy matrices impacts on homocysteine levels and gut microbiota composition of hyperhomocysteinemic mice.

Several studies highlighted a correlation between folic acid deficiency and high plasma homocysteine concentration, considered a risk factor for multifactorial diseases. Natural folates represent an emerging alternative strategy to supplementation with synthetic folic acid, whose effects are controversial. The present work was, therefore, performed in hyperhomocysteinemic mice to study the impact of supplementation with dairy matrices containing natural folates on plasma homocysteine levels and faecal microbiota composition. Forty mice were divided into six groups, two of which fed control or folic acid deficient (FD) diets for 10 weeks. The remaining four groups were fed FD diet for the first 5 weeks and then shifted to a standard control diet containing synthetic folic acid (R) or a FD diet supplemented with folate-enriched fermented milk (FFM) produced by selected lactic acid bacteria, fermented milk (FM), or milk (M), for additional 5 weeks. Supplementation with dairy matrices restored homocysteine levels in FD mice, although impacting differently on hepatic S-adenosyl-methionine levels. In particular, FFM restored both homocysteine and S-adenosyl-methionine levels to the control conditions, in comparison with FM and M. Next generation sequencing analysis revealed that faecal microbiota of mice supplemented with FFM, FM and M were characterised by a higher richness of bacterial species in comparison with C, FD and R groups. Analysis of beta diversity highlighted that the three dairy matrices determined specific, significant variations of faecal microbiota composition, while hyperhomocysteinemia was not associated with significant changes. Overall, the results represent a promising starting point for the applicability of food matrices enriched in natural folates to manage hyperhomocysteinemia.

Impaired homocysteine metabolism in patients with alcoholic liver disease in Taiwan.

​Impaired homocysteine metabolism plays an important role in alcoholic liver disease (ALD); however, there are limited data about its relationship with the risk and severity of patients with ALD in Taiwan. To understand plasma homocysteine and related vitamin concentrations in patients with ALD in Taiwan, we recruited 50 male patients with ALD from Cathay General Hospital, with 49 age-and gender-matched healthy adults as the control group. The Institutional Review Board for Human Studies approved the study, and informed consent was obtained from all patients prior to blood collection. Significantly higher plasma homocysteine concentrations but lower folate concentrations were obtained from patients with ALD. In addition, patients with ALD showed a significant lower erythrocyte reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio but higher plasma thiobarbituric acid-reactive substance (TBARS) concentration, which indicated that oxidative stress was occurring in patients with ALD. A negative correlation between plasma folate and homocysteine was observed in all subjects. There was also a negative correlation between plasma homocysteine and the erythrocyte GSH/GSSG ratio which indicated impaired homocysteine metabolism may have disrupted the antioxidative status. In addition, patients in Child-Pugh Class B and C showed higher plasma vitamin B12 concentrations than did patients without cirrhosis and patients in Child-Pugh Class A. These findings show that impaired homocysteine metabolism was observed in patients with ALD in Taiwan. In addition, the plasma vitamin B12 concentration may reflect the degree of liver injury.

Hyper-Homocysteinemia: A Potential Indicator of Acute Pancreatitis

Objectives: Hyper-homocysteinemia, reportedly, is closely associated with some known vascular dysfunctions, thrombosis and even inflammations. However, till now rare studies were directed to the association between hyperhomocysteinemia and acute pancreatitis (AP). The illumination of this potential association is expected to benefit therapies of AP. In this regard, this study aims at digging the underlying association between hyper-homocysteinemia and AP. Methods: In this study, 160 patients with AP were involved. The plasma levels of homocysteine of these patients were measured. The patients were divided into two groups, based on the serum homocysteine concentration. Patients with high plasma homocysteine concentrations (C>15 µmol/L) were classified as Group 1, while the rest with normal plasma homocysteine concentrations (5 µmol/L ≤ C ≤ 15 µmol/L) were identified as Group 2. Then, the lipid levels for the two groups were studied to detect whether there existed a synergistic effect of hyper-homocysteinemia and hypertriglyceride on AP. Results: Almost half (46.9%) of the patients with AP were found to bear hyper-homocysteinemia in this study. However, patients in Group 1 were found to have lower triglyceride and total cholesterol levels than those in Group 2, with P=0.038 and P=0.046 respectively. In addition, more patients in Group 2 had hyper-triglyceride and hyper-total cholesterol than those in Group 1, though the differences were not significantly observed. Conclusions: In conclusion, these studies showed that hyper-homocysteinemia may be a very important indicator of a high risk of AP. So, more attention should be paid to hyper-homocysteinemia in the progress of AP.

Methionine‐induced hyperhomocysteinemia impairs the antioxidant ability of high‐density lipoproteins without reducing in vivo macrophage‐specific reverse cholesterol transport

High plasma homocysteine concentrations have been associated with increased risk of cardiovascular disease both in humans and experimental animal models, whereas plasma HDL-cholesterol concentration is inversely correlated with such disorders. This work aimed to study the impact of methionine-induced hyperhomocysteinemia (HHcy) on two major antiatherogenic functions of HDL, namely their capacity to prevent LDL oxidation and induce in vivo macrophage-specific reverse cholesterol transport. Methionine-induced HHcy in mice resulted in an approximately 20% decreased concentration of HDL-cholesterol and HDL main protein component, apolipoprotein A-I. The HDL potential to resist oxidation as well as to prevent LDL oxidative modification was impaired in hyperhomocysteinemic mice. Activities of paraoxonase-1 and platelet activation factor acetylhydrolase, two of the main HDL-associated enzymes with antioxidant activity, were reduced. The ability of HDL to efflux cholesterol from macrophages was decreased in hyperhomocysteinemic mice; however, the in vivo macrophage-specific reverse cholesterol transport measured as the output of labeled cholesterol into feces did not significantly differ between groups. Our data indicate that the HDL from methionine-induced hyperhomocysteinemic mice was more prone to oxidation and displayed lower capacity to protect LDL against oxidative modification than that of control mice, highlighting a mechanism by which a diet-induced HHcy may facilitate progression of atherosclerosis.

A Pilot Study of the Nutritional Status of Opiate-Using Pregnant Women on Methadone Maintenance Therapy

Pregnant women in methadone maintenance therapy may have poor nutrition during pregnancy. In 2006–2008, methadone-treated pregnant women (n = 22) were recruited at an urban academic medical center and compared with nondrug-using pregnant women (n = 119) at 20–35 weeks’ gestation. We measured adiposity using prepregnancy body mass index (BMI), dietary intake using a food frequency questionnaire, and micronutrient and essential fatty acid status using biomarkers. Methadone-treated women had lower BMI, consumed more calories, had lower serum carotenoid concentrations, and higher plasma homocysteine concentrations than controls. The study's limitations and implications for future research are discussed.

Factors Contributing to the Resistivity of a Higher Casein Diet against Choline Deficiency-Induced Hyperhomocysteinemia in Rats

The mechanism by which feeding a higher casein diet results in resistance to choline deprivation-induced hyperhomocysteinemia was investigated in rats. Plasma homocysteine concentration was significantly lower in rats fed a 30% casein diet (30C) than in rats fed a 10% casein diet (10C). Choline deprivation did not enhance plasma homocysteine concentration in rats fed 30C, while it significantly enhanced plasma homocysteine concentration in rats fed 10C. The choline deprivation-induced enhancement of plasma homocysteine concentration in rats fed 10C was significantly suppressed by methionine supplementation in a dose-dependent manner in the range of 0.1 to 0.3%, but the suppressive effect of methionine became smaller with an increase in supplementation level in the range of 0.3 to 0.5%. At a 0.5% supplementation level, methionine did not exhibit any suppressive effect on choline deprivation-induced hyperhomocysteinemia. The higher plasma homocysteine concentration in rats fed choline-deprived 10C+0.5% methionine was significantly decreased by concurrent supplementation with 0.32% glycine+0.94% serine to the level of rats fed 10C. Raising dietary total amino acid level by adding 3.61% branched-chain amino acids (BCAA)+4.5% acidic amino acids (AAA) to choline-deprived 10C+0.5% methionine+0.32% glycine+0.94% serine resulted in a further decrease in plasma homocysteine concentration to a level lower than the level in rats fed 10C. Choline deprivation-induced increases in hepatic S-adenosylhomocysteine and homocysteine concentrations were significantly suppressed by supplementation with glycine+serine and further suppressed by BCAA+AAA. Hepatic cystathionine β-synthase activity and its gene expression were significantly increased by BCAA+AAA. Hepatic triglyceride concentration changed in a manner similar to that of plasma homocysteine concentration. The results indicate that there are at least three factors contributing to the resistivity of rats fed a higher casein diet (30C) to choline deprivation-induced hyperhomocysteinemia, i.e., higher intake of methionine, higher intake of glycine and serine, and higher intake of other amino acids such as BCAA and AAA.

Hyperhomocysteinemia is a risk factor for colorectal adenoma in women

Homocysteine is involved in a one-carbon transfer reaction, which is important for DNA synthesis and methylation. High level of plasma homocysteine, biochemical marker of folate status, is known to be a risk factor for cancer. However, it is inconclusive as to whether plasma homocysteine concentration can predict colorectal adenoma. We conducted a case-control study to determine whether hyperhomocysteinemia is a risk factor for adenoma. Data from 1,039 subjects who underwent a colonoscopy and plasma homocysteine concentration determination during health examinations at single center over a two-year period were analyzed. The subjects were classified into two groups (422 adenoma and 617 controls). Subjects defined as having advanced adenomas were those with more than three adenomas, over 1 cm in size, high grade dysplasia, or villous components. Male, old age, high body mass index, low high-density lipoprotein-cholesterol, smoking, fasting glucose, and past history of colon polyps were significantly associated with adenoma according to multiple logistic regression. According to subgroup analysis by gender, plasma homocysteine concentration was not associated with adenoma in males; however, a high plasma homocysteine concentration significantly increased the risk of adenoma as well as advanced adenoma in females. Hyperhomocysteinemia is a risk factor for colorectal adenoma in women.

Maternal one‐carbon metabolism, MTHFR and TCN2 genotypes and neural tube defects in India

Neural tube defects (NTDs) are among the most common severe congenital malformations, representing a long-term public health burden in India. A deranged one-carbon metabolism and genes regulating this metabolism have been linked to NTDs. Vitamin B(12) deficiency is reported to be more prevalent than folate deficiency in the Indian population. We investigated the role of maternal nutritional and genetic markers related to one-carbon metabolism in the etiology of NTDs. We conducted a multicenter case-control study to compare plasma folate, vitamin B(12) , homocysteine and holo-transcobalamin levels, and polymorphisms in methylenetetrahydrofolate reductase (MTHFR, 677C>T, 1298A>C, 1781G>A and 236+724A>G) and transcobalamin (TCN2, 776C>G) genes, in 318 women with NTD-affected offspring (cases) and 702 women with apparently healthy offspring (controls). The samples were collected at diagnosis in cases and at delivery in controls. We observed a significant association of high maternal plasma homocysteine concentrations with NTDs in the offspring (p = 0.026). There was no association of maternal folate or B(12) levels with NTDs (p > 0.05) but low maternal holo-transcobalamin predicted strong risk of NTDs in the offspring (p = 0.003). The commonly associated maternal polymorphism 677C>T in the MTHFR gene did not predict risk of NTDs in the offspring (p > 0.05) and 1298A>C and 1781G>A polymorphisms in MTHFR were protective (p = 0.024 and 0.0004 respectively). Maternal 776C>G polymorphism in TCN2 was strongly predictive of NTD in the offspring (p = 0.006). Our study has demonstrated a possible role for maternal B(12) deficiency in the etiology of NTDs in India over and above the well-established role of folate deficiency.

Genetic Polymorphism of Methylenetetrahydrofolate Reductase (MTHFR) and Coronary Artery Disease.

A high plasma homocysteine concentration is a risk factor for atherosclerotic disease and venous thrombosis. Homocysteine levels are influenced by folic acid, vitamin B 6 and vitamin B 12, as well as by hereditary factors. A common genetic variant of the methylenetetrahydrofolate reductase (MTHFR) gene CC 677 T) is associated with thermolability of the MTHFR enzyme and elevated plasma homocysteine concentration, especially in those with low folic acid concentration. The prevalence of point mutation (nucleotide 677 C --> T) in MTHFR was measured in patients with coronary artery disease (CAD) who all underwent coronary artery bypass surgery (62 cases; age 64.0 +/- 9.5 years), and was compared with, age-matched control subjects. In patients with coronary artery disease (CAD), we investigated the prevalence of point mutation (nucleotide 677 C --> T) in MTHFR in comparison with control subjects. Heterozygous (C/T) prevalence for the 677 C --> T mutation in the MTHFR was higher in patients with CAD than in control subjects (P < 0.05). The prevalence of homozygosity (C/C) for wild-type MTHFR was lower in patients with CAD in comparison with control subjects (P < 0.05).

Relative Hyperhomocysteinemia in Patients with Panic Disorder: A Case-Control Study

Background: The aim of this work was to examine a possible association between a clinically relevant panic disorder and plasma total homocysteine concentration. Methods: 23 patients with panic disorder with or without agoraphobia confirmed by a standardized clinical interview (Structural Clinical Interview for DSM-IV-German version) and 23 healthy controls matched for gender and age completed questionnaires (SCL-K9, STAI, ADS, STAXI) and had blood drawn after a 15 min rest. Plasma total homocysteine concentrations were measured by competitive enzyme immunoassay. Interfering variables such as age, gender, smoking status, comorbid depression and medication were controlled for. Results: Patients with panic disorder had higher plasma homocysteine concentrations in comparison to the control group (mean value 11.00 vs. 9.14 µmol/l, p = 0.04 with age, gender, smoking status, comorbid depression and antidepressant medication being controlled for). Furthermore, homocysteine plasma concentration was positively correlated with Global Severity of Symptoms (SCL-K9, r_Pearson = 0.41, p < 0.01). Conclusion: The findings of this study suggest a link between elevated plasma homocysteine levels and panic disorder. This raises a new hypothesis of another pathway to an increased risk of cardiovascular events in anxious individuals.

Higher Maternal Plasma Folate but Not Vitamin B-12 Concentrations during Pregnancy Are Associated with Better Cognitive Function Scores in 9- to 10- Year-Old Children in South India1–3

Folate and vitamin B-12 are essential for normal brain development. Few studies have examined the relationship of maternal folate and vitamin B-12 status during pregnancy and offspring cognitive function. To test the hypothesis that lower maternal plasma folate and vitamin B-12 concentrations and higher plasma homocysteine concentrations during pregnancy are associated with poorer neurodevelopment, 536 children (aged 9–10 y) from the Mysore Parthenon birth cohort underwent cognitive function assessment during 2007–2008 using 3 core tests from the Kaufman Assessment Battery, and additional tests measuring learning, long-term storage/retrieval, attention and concentration, and visuo-spatial and verbal abilities. Maternal folate, vitamin B-12, and homocysteine concentrations were measured at 30 ± 2 wk gestation. During pregnancy, 4% of mothers had low folate concentrations (<7 nmol/L), 42.5% had low vitamin B-12 concentrations (<150 pmol/L), and 3% had hyperhomocysteinemia (>10 μmol/L). The children’s cognitive test scores increased by 0.1–0.2 SD per SD increase across the entire range of maternal folate concentrations (P < 0.001 for all), with no apparent associations at the deficiency level. The associations with learning, long-term storage/retrieval, visuo-spatial ability, attention, and concentration were independent of the parents’ education, socioeconomic status, religion, and the child’s sex, age, current size, and folate and vitamin B-12 concentrations. There were no consistent associations of maternal vitamin B-12 and homocysteine concentrations with childhood cognitive performance. In this Indian population, higher maternal folate, but not vitamin B-12, concentrations during pregnancy predicted better childhood cognitive ability. It also suggests that, in terms of neurodevelopment, the concentration used to define folate deficiency may be set too low.

Tratamientos vitamínicos para disminuir la concentración de homocisteína: ¿reducen el riesgo de enfermedad cerebrovascular en prevención primaria?

High plasma homocysteine (Hcy) concentration or hyperhomocysteinemia is associated with an increased vascular risk of disease in case-control studies and, to a lesser extent, in prospective studies. Several large randomized, double-blind, placebo-controlled trials have been already conducted using specific vitamin therapies with the aim of reducing secondary cardiovascular (HOPE, NORVIT, WAFACS and WENBIT studies) and cerebrovascular (VISP study) disease risk. The results from these major secondary prevention trials and one meta-analysis, that included other smaller studies up to 12 of them, showed that treatment decreased plasma Hcy concentration but failed to reduce cardiovascular risk. It is nevertheless noteworthy that a recent meta-analysis addressing the effects of these vitamin treatments on cerebrovascular risk found a positive effect on primary stroke prevention. These data would be consistent with the fact that increased Hcy is known to be associated more strongly with stroke risk than with cardiovascular risk. Moreover, folic acid supplementation in grain food has recently been shown to be associated with a decreased stroke incidence in USA and Canada. Obviously, these data on primary stroke prevention will require extensive confirmation. However, there now appear to be more reasons to expect a positive outcome of Hcy intervention studies.

Homocysteine, vitamin B12 and folic acid plasma levels in relation to cognitive functions in an Egyptian elderly group

Several studies suggested that elevated plasma total homocysteine (tHcy) concentrations are associated with cognitive impairment and dementia. High plasma homocysteine concentrations can be largely attributed to inadequate status of folic acid and vitamin B12. On the other hand, data from several studies indicate that plasma homocysteine increases with age, independent of vitamin status. We investigated the relation between plasma tHcy, vitamin B12 and folic acid levels and cognitive functions in an elderly Egyptian group. We also studied the effect of vitamin B12 and folic acid supplementation on plasma tHcy and cognitive functions. About 56 subjects (30 males and 26 females) similar in socio-economic class (upper-middle), with an age range of 60-70 years completed the study course. All were healthy working professionals. Clinical, nutritional and anthropometric evaluations were performed. Cognitive function evaluation using the Kendrick Battery for detecting dementia was applied. Biochemical analysis for blood homocysteine, vitamin B12 and folic acid was performed. All evaluations were performed at the beginning of the study and after four months of supplementation with biscuits rich in vitamin B12 and folic acid. The results of the study show that there is a significant correlation between plasma tHcy and cognitive functions, both object learning test (OLT) (short-term memory) and digit copying test (DCT) (attention focus) both before p (<0.01) and after p (<0.01) vitamin supplementation and also between vitamin B12 and cognitive functions before and after supplementation p (<0.05). Significant decrease in plasma tHcy and increase in vitamin B12 and folic acid level is recorded after supplementation p (<0.01). There is a significant improvement in cognitive functions, both OLT and DCT after vitamin supplementation p (<0.05). In conclusion, elevated plasma tHcy level and low vitamin B12 levels are positively correlated to impairment in cognitive functions. Vitamin B12 and folic acid supplementation decreased plasma tHcy level and improved cognitive functions. We recommend vitamin B12 and folic acid supplementation for elderly.

The Antiatherogenic Function of HDL Is Impaired in Hyperhomocysteinemic Subjects

High plasma homocysteine concentrations have been associated with increased risk of cardiovascular disease, whereas plasma HDL concentration is inversely correlated to such disorders. We hypothesized that hyperhomocysteinemic subjects may have dysfunctional HDL. We therefore investigated the ability of serum from hyperhomocysteinemic male and female subjects (n = 10) and control subjects (n = 10) to induce cholesterol efflux and to inhibit release of inflammatory mediators from human umbilical vein endothelial cell. We found that serum from hyperhomocysteinemic subjects had impaired ability to induce cholesterol efflux from lipid-loaded macrophages compared with healthy controls. HDL from those with markedly raised homocysteine concentrations had a reduced antiinflammatory effect in tumor necrosis factor-α–activated endothelial cells with an attenuated suppressive effect on interleukin-6 growth-related oncogene-α release. Also, the activity of paraoxonase in serum, a multifunctional enzyme with antioxidative effects in relation to the function of HDL, was significantly reduced in hyperhomocysteinemic subjects, in particular those with markedly raised homocysteine concentration. Our findings suggest that hyperhomocysteinemic individuals have dysfunctional HDL particles with attenuated antiatherogenic activity and may represent a novel explanation for the increased risk of cardiovascular events in these individuals.

Effects of red wine polyphenolic compounds on paraoxonase-1 and lectin-like oxidized low-density lipoprotein receptor-1 in hyperhomocysteinemic mice

Hyperhomocysteinemia, or abnormally high plasma homocysteine (Hcy) concentration, has often been associated with vascular thrombosis and the development of premature atherosclerosis. Many studies have shown that moderate wine consumption has potential beneficial effects related to the prevention of atherosclerosis, in part attributed to the biological properties of polyphenolic components, mainly flavonoids. The aim of the present study is to determine the effects of a red wine polyphenolic extract (PE) administration on hyperhomocysteinemia due to cystathionine β-synthase (CBS) deficiency and on the associated biochemical markers of hepatic and endothelial dysfunctions in mice. Red wine PE was added for 4 weeks to the drinking water of heterozygous CBS-deficient mice fed a high-methionine diet, a murine model of hyperhomocysteinemia. Red wine PE supplementation at low dose significantly reduced plasma Hcy levels and restored the hepatic and plasma-decreased paraoxonase-1 activity induced by chronic hyperhomocysteinemia. Moreover, aortic expression of proinflammatory cytokines and adhesion molecules and levels of soluble lectin-like oxidized low-density lipoprotein receptor-1 were reduced in hyperhomocysteinemic mice fed the red wine PE supplementation. These findings suggest that red wine PE administration in low quantities has beneficial effects on biochemical markers of endothelial dysfunction due to hyperhomocysteinemia.

Hyperhomocysteinemia and recurrent carotid stenosis.

BackgroundHyperhomocysteinemia has been identified as a potential risk for atherosclerotic disease in epidemiologic studies. This study investigates the impact of elevated serum homocysteine on restenosis after carotid endarterectomy (CEA).MethodsIn a retrospective study, we compared fasting plasma homocysteine levels of 51 patients who developed restenosis during an eight year period after CEA with 45 patients who did not develop restenosis. Restenosis was defined as at least 50% stenosis and was assessed by applying a routine duplex scan follow up investigation. Patients with restenosis were divided into a group with early restenosis (between 3 and 18 months postoperative, a total of 39 patients) and late restenosis (19 and more months; a total of 12 patients).ResultsThe groups were controlled for age, sex, and risk factors such as diabetes, nicotine abuse, weight, hypertension, and hyperlipidemia. Patients with restenosis had a significant lower mean homocysteine level (9.11 μmol/L; range: 3.23 μmol/L to 26.49 μmol/L) compared to patients without restenosis (11.01 μmol/L; range: 5.09 μmol/L to 23.29 μmol/L; p = 0.03).Mean homocysteine level in patients with early restenosis was 8.88 μmol/L (range: 3.23–26.49 μmol/L) and 9.86 μmol/L (range 4.44–19.06 μmol/L) in late restenosis (p = 0.50).ConclusionThe finding suggests that high plasma homocysteine concentrations do not play a significant role in the development of restenosis following CEA.

Heterogeneity and Lack of Good Quality Studies Limit Association Between Folate, Vitamins B-6 and B-12, and Cognitive Function

We conducted a systematic review to evaluate the association between folate, vitamin B-6, vitamin B-12, and cognitive function in the elderly. Our search was conducted in Medline for English-language publications of human subjects from 1966 through November 2006; we supplemented these results with information from article reviews and domain experts. We included longitudinal cohort and case-control studies of B vitamins and analyses of cognitive tests or Alzheimer’s disease. We evaluated the quality and heterogeneity of study outcomes and assessed 30 different cognitive function tests. Of 24 studies that met eligibility criteria, 16 were determined to be of fair quality. A majority of the studies reviewed 2 or more B vitamins. Considerable heterogeneity was found among B-vitamin–level thresholds, comparisons, and data analyses. Six of 10 folate studies reported a significant association between low baseline blood folate concentrations and subsequent poor test performance in the global cognitive domain, and 4 of 9 folate studies found associations between low blood folate concentrations and increased prevalence of Alzheimer’s disease. Studies did not reveal an association of vitamin B-6 and vitamin B-12 blood concentrations with cognitive-test performance or Alzheimer’s disease, nor was B-vitamin dietary intake associated with cognitive function. Higher plasma homocysteine concentrations were associated with poorer cognitive function. Although the majority of studies indicated that low blood folate concentrations predicted poorer cognitive function, data supporting this association were limited because of the heterogeneity in cognition-assessment methodology, and scarcity of good quality studies and standardized threshold levels for categorizing low B-vitamin status.

The effect of homocysteine reduction by B-vitamin supplementation on inflammatory markers

Hyperhomocysteinemia has been associated with vascular disease in many epidemiological studies. However, the pathophysiology is unclear. It is postulated that increased levels of homocysteine induce an inflammatory response in endothelial cells, mediated by pro-inflammatory cytokines and chemokines. The aim of this study was to investigate whether plasma concentrations of interleukin-6, interleukin-8, C-reactive protein, and monocyte chemoattractant protein-1 are increased with higher plasma homocysteine concentrations and whether decreasing homocysteine by vitamin supplementation decreases the concentration of these markers. Plasma homocysteine, interleukin-6, interleukin-8, C-reactive protein, and monocyte chemoattractant protein-1 concentrations were measured in 230 volunteers before and after 8 weeks of multivitamin supplementation (folic acid, B(6), and B(12)). At baseline, plasma homocysteine concentration was weakly associated with interleukin-8, but not with interleukin-6, C-reactive protein or monocyte chemoattractant protein-1. Vitamin supplementation resulted in a significant decrease in homocysteine concentration, but no effect on interleukin-6, interleukin-8, C-reactive protein or monocyte chemoattractant protein-1 was observed. At baseline homocysteine was only weakly correlated with interleukin-8, but not with interleukin-6, C-reactive protein or monocyte chemoattractant protein-1. Vitamin supplementation affected homocysteine concentration, but not cytokine levels. The hypothesis that hyperhomocysteinemia increases arteriosclerotic or thrombotic risk through vascular inflammation was not supported by this study.

Hyperhomocysteinaemia and Vitamin B12 Deficiency: The Long-Term Effects in Cardiovascular Disease

Background: An elevated plasma homocysteine level is an established risk factor for cardiovascular disease. Vitamin B12 plays a key role in homocysteine metabolism and could be the main factor in causing cardiovascular disease as well. Objectives: The aim of this study was to assess whether vitamin B12 deficiency or hyperhomocysteinaemia is associated with recurrent cardiovascular events. Methods: Overall, 211 patients discharged alive from our Coronary Care Unit were recruited from February till May 1998. Serum vitamin B12 and plasma homocysteine levels were measured in fasting blood samples. Patient characteristics, medical information and cardiovascular risk factors were assessed from medical files. Patients were followed for 5 years and the prevalence of cardiovascular mortality and morbidity was collected. Results: In the follow-up period of 810 person-years, 48 (21%) of the patients experienced a nonfatal recurrent cardiovascular event and another 14 (7%) died of a cardiovascular cause. Among those with ischaemic heart disease at discharge, no difference in survival was found between the patients with a low (<250 pmol/l) or a high vitamin B12 level (p = 0.21). In patients with hyperhomocysteinaemia (>16 µmol/l), an increased risk of a recurrent cardio vascular event (p = 0.05) in comparison to those with normal plasma homocysteine levels was proven (adjusted hazard ratio of 2.22 (95% CI: 1.40–3.04). Conclusions: In conclusion, high plasma homocysteine concentration, but not a low serum vitamin B12 concentration, increases the risk of cardiovascular morbidity and mortality in patients with ischaemic heart disease.