Plasma homocysteine concentrations and insulin sensitivity in hypertensive subjects

Elevated Plasma Homocysteine Level Associated with Further Left Ventricular Structure and Function Damages in Type 2 Diabetic Patients: A Three-Dimensional Speckle Tracking Echocardiography Study

Aims: The aims of this study were to explore the left ventricular (LV) structural remodeling and its risk factors in type 2 diabetes mellitus (T2DM) patients with or without hyperhomocysteinemia (hHcy) and to detect the accompanied LV dysfunction using three-dimensional speckle tracking echocardiography (3DSTE). Methods: There were totally 80 T2DM patients with undamaged LV ejection fraction (≥55%) in this study, 40 of whom were also diagnosed with hHcy as co-morbidity. Forty age- and gender-matched controls were also recruited. The risk factors and corresponding diagnostic values for LV remodeling (LVR) were, respectively, determined using logistic regression and area under the receiver operating characteristic curves (AUC). The 3DSTE was used to measure global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS), and global radial strain (GRS). Results: The constituent ratio of LV geometry showed significant differences among the study populations (P = 0.01). Compared with the controls, three types of LVR accounted for larger proportion in the two T2DM groups, whereas LV hypertrophy was most prevalent in those with T2DM and hHcy. Glycosylated hemoglobin (HbA1c), total plasma homocysteine (tHcy), and HbA1c plus tHcy were all significant risk factors associated with LVR in T2DM patients (AUC values: 0.741, 0.746 and 0.851, respectively). The patients with T2DM alone had significantly lower GLS and GAS than the controls (both P < 0.05). The patients with T2DM and hHcy had significantly lower GLS, GCS, GAS, and GRS than the controls (all P < 0.001), and also had significantly lower GLS, GCS, and GRS than the patients with T2DM alone (all P < 0.05). Conclusions: The 3DSTE plus conventional echocardiography could be used as an effective supplement for detecting early and occult cardiac damages in T2DM patients with plasma homocysteine at normal or elevated levels.

Repeatedly heated mix vegetable oils-induced atherosclerosis and effects of Murraya koenigii

Background

Statins are considered as standard drugs to control cholesterol levels, but their use is also associated with renal hypertrophy, hemorrhagic stroke, hepatomegaly, and myopathy. Murraya koenigii is an herb that is used in traditional cuisine and as a medicine in South Asia. Here we assessed the antidyslipidemic and antiatherosclerotic effects of this spice in repeated heated mix vegetable oils (RHMVO)-induced atherosclerotic models.

Methods

Aqueous extract of M. koenigii leaves (Mk LE) was prepared and its phytoconstituents were determined. Rabbits were divided into 5 groups (n = 10). Except for the control group, all the other four groups were treated with RHMVO for 16 weeks (dose = 2 ml/kg/day) to induce dyslipidemia and atherosclerosis. These groups were further treated for 10 weeks either with 300 and 500 mg/kg/day Mk LE, lovastatin, RHMVO, or left untreated. Body and organ weights were measured along with oxidative stress and tissue damage parameters. Lipid profile and hepatic function markers were studied. Atheroma measurement and histopathological examination were also performed in control and treated groups.

Results

Mk LE significantly (p < 0.05) attenuated RHMVO-induced dyslipidemia and atheroma formation. Furthermore, fat accumulation and lipid peroxidation in hepatic tissues were reduced by Mk LE in a dose-dependent manner. Our results indicated that the antidyslipidemic effects of Mk LE in 500 mg/kg/day dose were comparable to lovastatin. Additionally, oxidative stress markers were reduced much more significantly in Mk LE-500 than in the statin group (p < 0.05).

Conclusions

This study recommends Mk LE as a potent antioxidant and lipid-lowering natural medicine that can attenuate the RHMVO-induced atherosclerotic in optimal doses and duration. Therefore, Mk LE can be accessible, cheap, and free of adverse effects alternate to statins.

Association of Homocysteine with Aysmptomatic Intracranial and Extracranial Arterial Stenosis in Hypertension Patients

Elevated plasma homocysteine (Hcy) is suggested as an independent risk factor for stroke. We aimed to investigate the association of Hcy concentration with intracranial atherosclerosis (ICAS) and extracranial AS (ECAS) in hypertensive patients without stroke in Chinese population and to explore modified effect of methylenetetrahydrofolate reductase (MTHFR) C677T on their relationship. The stenosis of intracranial and extracranial arteries were evaluated in a total of 929 subjects through computerized tomographic angiography (CTA) from aortic arch to the skull base. Hcy concentration showed significantly association with both ICAS (OR: 1.105; 95% CI: 1.057-1.155) and ECAS (OR: 1.096; 95% CI: 1.047-1.146) for 1 µmol/L increment in Hcy. Meanwhile, hyperhomocysteinemia (≥15 µmol/L) was also displayed association with ICAS (OR: 1.587; 95% CI: 1.029-2.446) and ECAS (OR: 2.164; 95% CI: 1.392-3.364) after fully adjustment. Furthermore, in the subgroup analysis, such association remained significant only in the subjects that were younger, with normal renal function and with MTHFR 677 C allele. Our study showed the significant association of Hcy with ECAS and ICAS in asymptomatic hypertension patients. Hcy played a universal effect on the cervico-cerebral atherosclerosis. Such association was modified by the MTHFR C677T genotype.

An association of serum ALT with elevated blood pressure in senior adults: a case-control study

Hypertension is a major risk factor for cardiovascular diseases in China; hence, identifying good serum markers might provide cost benefits in terms of reducing morbidity rates. In this population-based case-control study, participants were recruited from five districts in Hunan province, and 416 cases were matched with an equal number of controls. Markers related to elevated blood pressure were assessed: Body Mass Index, total cholesterol, triglycerides, fasting blood glucose, and creatinine. Three potential serum markers homocysteine (HCY), C-reactive protein (CRP), and alanine aminotransferase (ALT) were dichotomized as normal or high level. Binary logistic regression was used to determine odds ratios (ORs) and 95% confidence intervals (CIs). The findings showed that ALT is a powerful serum marker for predicting high risk of high blood pressure with OR = 2.94, 95% CI (1.44-6.02), while there were no significant differences between cases and controls for HCY and CRP. Additionally, it seems likely that high concentrations of HCY conferred a protective effect against elevated blood pressure. When adjusted for sex, ORs for hypertensive females were nearly five times higher than for hypertensive males (OR = 4.34, 95% CI = 1.17-16.04). The study strongly supports findings showing ALT is a potential indicator for patients with hypertension.

Deep analyses of the associations of a series of biomarkers with insulin resistance, metabolic syndrome, and diabetes risk in nondiabetic middle-aged and elderly individuals: results from a Chinese community-based study

OBJECTIVE

The current study was designed to perform deep analyses of the associations of biomarkers, including high-sensitivity C-reactive protein (hs-CRP), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), and homocysteine (Hcy), with insulin resistance (IR), metabolic syndrome (MetS), and diabetes risk and evaluate the abilities of biomarkers to identify IR, MetS, and diabetes risk in Chinese community-dwelling middle-aged and elderly residents.

PARTICIPANTS AND METHODS

A total of 396 participants older than 45 years underwent physical examinations and laboratory analyses following standardized protocol.

RESULTS

Serum hs-CRP concentrations were able to identify MetS, Chinese diabetes risk score (CDRS) ≥4, high-density lipoprotein-cholesterol (HDL-c) <0.9/1.0 mmol/L, and HDL-c <1.0/1.3 mmol/L (P<0.05 for all). Serum NT-proBNP concentrations were able to identify homeostasis model assessment of IR >1.5, CDRS ≥4, overweight, and blood pressure (BP) ≥140/90 mmHg (P<0.05 for all). Serum Hcy concentrations were able to identify CDRS ≥4, general obesity, overweight, and BP ≥140/90 mmHg (P<0.05 for all). Serum hs-CRP concentrations were independently associated with MetS as well as HDL-c <1.0/1.3 mmol/L and HDL-c <0.9/1.0 mmol/L (P<0.05 for all). Serum NT-proBNP concentrations were independently associated with BP ≥140/90 mmHg (P<0.05). Serum Hcy concentrations were independently associated with CDRS ≥4 (P<0.05).

CONCLUSION

Serum HDL-c levels were the major determinant of the associations between serum hs-CRP levels and MetS and the key link between inflammation and MetS. There was no other association of these biomarkers with IR, MetS, and diabetes risk after full adjustment.

Elevated Homocysteine Levels Are Associated With the Metabolic Syndrome and Cardiovascular Events in Hypertensive Patients

BACKGROUND

Hyperhomocysteinemia and the metabolic syndrome are established cardiovascular risk factors and are frequently associated with hypertension. The relationship of plasma homocysteine (Hcy) with the metabolic syndrome and insulin resistance, however, is debated and studies in hypertensive patients are limited. In this study, we have investigated the association of Hcy with the metabolic syndrome and cerebro- cardiovascular events in hypertension.

METHODS

In 562 essential hypertensive patients who underwent accurate assessment of fasting and postload glucose metabolism, insulin sensitivity, and renal function, we measured plasma levels of Hcy, vitamin B12, folate, and fibrinogen and assessed the prevalence of the metabolic syndrome and of coronary heart and cerebrovascular disease (CVD).

RESULTS

Patients with the metabolic syndrome had significantly higher plasma Hcy levels. After correction for covariates, increasing Hcy levels were associated with an increasing prevalence of the metabolic syndrome, coronary heart disease, and CVD. Plasma Hcy was directly correlated with age, waist circumference, fasting glucose, triglyceride, uric acid, and fibrinogen levels, and homeostatic model assessment index and inversely with creatinine clearance and high-density lipoprotein cholesterol, vitamin B12, and folate levels. Logistic regression analysis showed an independent association of Hcy levels with age, male gender, vitamin B12 and folate levels, and the metabolic syndrome. Logistic regression indicated also an independent association of Hcy with cerebro-cardiovascular disease that was independent of the metabolic syndrome.

CONCLUSIONS

Elevated plasma Hcy is associated with the metabolic syndrome in hypertensive patients. Prevalence of events increases with increasing plasma Hcy levels suggesting a contribution of Hcy to cerebro-cardiovascular diseases in these patients.

Subclinical carotid artery disease and plasma homocysteine levels in patients with hypertension

Information on the association between homocysteine (Hcy) levels and subclinical carotid artery disease is limited. We investigated the relationship of plasma Hcy concentration with carotid artery plaques and intima-media thickness (IMT) in patients with hypertension. In 486 essential hypertensive patients who underwent ultrasound examination of the carotid arteries, we measured plasma levels of Hcy, vitamin B12, folate, and C-reactive protein. Plaques were detected in 34% of the study patients. Plasma Hcy levels were significantly greater in hypertensive patients with evidence of carotid plaques than patients without carotid plaques. Carotid IMT progressively increased across quartiles of plasma Hcy levels. Multivariate regression showed that carotid IMT was independently related with age, blood pressure, C-reactive protein, and Hcy levels. In a logistic regression, age, blood pressure, triglyceride, and Hcy independently predicted the presence of carotid plaques. Thus, elevated plasma Hcy levels are associated with asymptomatic carotid disease in hypertensive patients suggesting a role of Hcy in the development and progression of carotid atherosclerosis in these patients.

Hyperhomocysteinemia, lipid and lipoprotein disturbances in patients with primary hypertension

PURPOSES

The main aim of the study was to answer two questions: what are the concentrations of total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, apo A-I (apolipoprotein A-I), apo B (apolipoprotein B) and Lp(a) (lipoprotein(a)) in serum of patients with primary hypertension and with hyperhomocysteinemia? Is there any correlation between the concentration of homocysteine in blood serum and investigated lipid and lipoprotein parameters in patients with primary hypertension?

MATERIAL/METHODS

We investigated 42 patients with primary hypertension, aged 22-57. The control group consisted of 20 healthy volunteers. The concentration of homocysteine in serum was evaluated using immunochemical method (FPIA - Fluorescence Polarization Immunoassay). The concentration of total cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides in blood serum were estimated using enzymatic method. Apo A-I, apo B and lipoprotein(a) were assessed using nephelometric method.

RESULTS

The analysis of the results revealed statistically significant lower concentrations of HDL-cholesterol and apo A-I in blood serum of patients with primary hypertension and hyperhomocysteinemia than in the population with hypertension and normohomocysteinemia. Negative correlation between homocysteine and HDL-cholesterol as well as apo A-I has been revealed.

CONCLUSION

Quantitative analysis of the concentration of lipids and lipoproteins in blood serum in patients with primary hypertension and hyperhomocysteinemia may suggest that this type of human population might be more susceptible to atherosclerosis than those with primary hypertension and normal values of homocysteine.

Correlation of serum homocysteine and previous history of gestational diabetes mellitus

Background

Gestational diabetes mellitus (GDM) is a common pregnancy condition. In this study, the risk of having a history of previous GDM (pGDM) on serum homocysteine level was assessed

Methods

Biomedical parameters, serum homocysteine, Insulin, homeostatic model assessment (HOMA) in women with (n = 52) and without pGDM (n = 51) were assessed. According to their current status of Oral Glucose Tolerance Test (GTT), the participants in each group were divided into two subgroups of normal or impaired GTT.

Results

Mean serum homocysteine in normal women was 8.56 ± 3.19 vs 11.44 ± 7.34 μmol/L (p < 0.01) in women with pGDM. Two groups had significant differences in respect to serum insulin levels (8.35 ± 5.12 vs 12.48 ± 5.44, p < 0.002), and HOMA-IR (1.90 ± 1.30 vs 2.91 ± 1.30, p < 0.002). In women without pGDM, serum homocysteine in normal and impaired GTT were 7.60 ± 1.69 and 10.52 ± 3.65 μmol/L (p = 0.03), respectively, while in women with pGDM, the figures were 8.38 ± 2.52 and 14.00 ± 10.17 (p < 0.01), respectively. In multi regression analysis an association between history of GDM and homocysteine levels was presented (OR: 7.71, 95% CI: 1.67-35.42, p < 0.001).

Conclusion

A trend of elevation of homocysteine is presented in women with pGDM, that is more prominent in women with impaired GTT, and shows a significant correlation with history of GDM. Further studies with larger sample size are suggested.

Effect of homocysteine-lowering treatment with folic Acid and B vitamins on risk of type 2 diabetes in women: a randomized, controlled trial

OBJECTIVE

Homocysteinemia may play an etiologic role in the pathogenesis of type 2 diabetes by promoting oxidative stress, systemic inflammation, and endothelial dysfunction. We investigated whether homocysteine-lowering treatment by B vitamin supplementation prevents the risk of type 2 diabetes.

RESEARCH DESIGN AND METHODS

The Women's Antioxidant and Folic Acid Cardiovascular Study (WAFACS), a randomized, double-blind, placebo-controlled trial of 5,442 female health professionals aged > or = 40 years with a history of cardiovascular disease (CVD) or three or more CVD risk factors, included 4,252 women free of diabetes at baseline. Participants were randomly assigned to either an active treatment group (daily intake of a combination pill of 2.5 mg folic acid, 50 mg vitamin B6, and 1 mg vitamin B12) or to the placebo group.

RESULTS

During a median follow-up of 7.3 years, 504 women had an incident diagnosis of type 2 diabetes. Overall, there was no significant difference between the active treatment group and the placebo group in diabetes risk (relative risk 0.94 [95% CI 0.79-1.11]; P = 0.46), despite significant lowering of homocysteine levels. Also, there was no evidence for effect modifications by baseline intakes of dietary folate, vitamin B6, and vitamin B12. In a sensitivity analysis, the null result remained for women compliant with their study pills (0.92 [0.76-1.10]; P = 0.36).

CONCLUSIONS

Lowering homocysteine levels by daily supplementation with folic acid and vitamins B6 and B12 did not reduce the risk of developing type 2 diabetes among women at high risk for CVD.

Elevation of fasting insulin and its association with cardiovascular disease risk in women with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is associated with premature atherosclerosis. We previously showed that SLE patients have a higher risk of insulin resistance (IR) and abnormal insulin secretion. The present study was to further investigate the relationship between fasting insulin levels and both classic and novel cardiovascular risk factors in patients with SLE. Body mass index (BMI), fasting glucose and insulin, lipid profile, oxidation markers, fibrinolytic factors, vascular function factors, and disease-specific variables were determined in a total of 87 female SLE patients. The homeostasis model assessment (HOMA) was used to evaluate the IR and secretion. SLE patients had significantly higher fasting insulin, HOMA IR, HOMA beta-cell, titers of autoantibodies against oxidized low density lipoprotein, systolic blood pressure, homocysteine, and brachial-ankle pulse wave velocity (baPWV) than age-matched healthy controls. There were no statistical differences in disease duration, anti-dsDNA, C3, C4, disease activity, and medication dosage between SLE patients stratified by fasting insulin levels. However, mean values for BMI, insulin, HOMA IR, HOMA beta-cell, triglyceride (TG), homocysteine, and baPWV were significantly higher in the SLE patients with hyperinsulinemia when compared with those SLE controls. In addition, fasting insulin levels were positively correlated with TG, homocysteine, blood pressure, plasminogen activator inhibitor 1, and baPWV in SLE patients. The elevation of fasting insulin levels in SLE patients is not only associated with IR, but is related to classic and novel cardiovascular risk factors. This study concludes that there is an insulin-related cardiovascular disease risk in SLE.

Influence of mental stress on the plasma homocysteine level and blood pressure change in young men

Objective. This study aimed to determine whether mental stress influences the plasma total homocysteine level or blood pressure in young men. Method. Twenty-seven male university students were assigned to a normal blood pressure group (24-h systolic blood pressure <125 mmHg and diastolic blood pressure <75 mmHg; 13 subjects) or a high blood pressure group (24-h systolic blood pressure > or =125 mmHg, or 24-h diastolic blood pressure > or =75 mmHg; 14 subjects). Wearing an ambulatory blood pressure monitoring device, subjects rested for 30 minutes, underwent an arithmetic test for 15 minutes, and rested again for 15 minutes. Blood samples were taken before and after the test. Plasma total homocysteine levels were measured. Heart rate, blood pressure, and sympathovagal balance were determined during the test. Results. The mean total homocysteine level at rest in the high blood pressure group was slightly, but not significantly, higher than that in the normal blood pressure group. The resting total homocysteine level was significantly higher in subjects with parental history of hypertension than in those without (p < 0.01). Blood pressure, heart rate, and the plasma total homocysteine level were increased significantly by mental stress (p < 0.05). The change in total homocysteine correlated significantly with the changes in systolic blood pressure and sympathovagal balance (p < 0.05). Conclusion. Resting total homocysteine level was significantly higher in male students with a parental history of hypertension than in those without. It was shown that mental stress elevates heart rate, blood pressure, sympathovagal activity, and the plasma total homocysteine level in young men.

Total plasma homocysteine correlates in women with gestational diabetes

AIM

We aim to assess serum total homocysteine (tHcy) associations with metabolic syndrome components and B-vitamins in women with gestational diabetes mellitus (GDM).

METHODS

We studied 61 consecutive pregnant women, 44 with GDM and 17 with normal glucose tolerance (CG). Serum homocysteine levels were analyzed by ELISA, using Bio-Rad reagents. Serum folates and vitamin B(12) concentrations were determined by chemiluminescent immunoassay, free fatty acids (FFA) and lipids enzymatically.

RESULTS

Serum homocysteine levels were similar in both the GDM and the CG groups (8+/-2.0 vs 7.4+/-1.1 micromol/l, respectively). Women with GDM in comparison to CG women were characterized by higher values of homeostasis model of insulin resistance (HOMA-IR) (2.8+/-1.7 vs 1.6+/-0.9, P<0.01), serum triglycerides (2.7+/-0.9 vs 1.9+/-0.5 mmol/l, P<0.01) and FFA (0.6+/-0.2 vs 0.46+/-0.2 mmol/l, P<0.05). In GDM women serum tHcy correlated with vitamin B(12) (r= -0.47, P<0.01) and folates (r= -0.51, P<0.001); in CG women with HOMA-IR, a marker of insulin resistance (r= -0.49, P<0.05). In multiple regression analysis with serum tHcy as a dependent variable, folate and vitamin B(12) entered the analysis in GDM women (beta= -0.42 and -0.34, respectively, P<0.05), whereas in CG cystatin C and HOMA-IR entered the analysis (P<0.05).

CONCLUSIONS

In women with GDM, serum homocysteine is significantly associated with vitamin B(12) and folate levels, while in healthy pregnant women with HOMA-IR and with kidney function. The results suggest the importance of the B-group vitamins in regulation of serum tHcy levels in women with insulin resistance/gestational diabetes, what might be relevant in protection against pregnancy complications associated with elevated tHcy in GDM women.

The 677 C/T MTHFR polymorphism is associated with essential hypertension, coronary artery disease, and higher homocysteine levels

BACKGROUND

Essential hypertension (EH) and cardiovascular disease are common, multifactorial disorders likely to be influenced by multiple genes of modest effect. The C677T methylenetetrahydrofolate reductase (MTHFR) gene polymorphism is related to MTHFR enzyme activity and to plasma homocysteine (Hcy) concentration. This study was designed to investigate an association of this polymorphism with coronary artery disease (CAD), EH, and healthy subjects.

METHODS

In this study, we measured serum folate, serum vitamin B12, and plasma homocysteine and determined the MTHFR C677T genotype of 78 patients with essential hypertension, 100 patients with coronary artery disease, and 100 healthy subjects. MTHFR genotypes were assessed by real-time polymerase chain reaction.

RESULTS

CC, CT, and TT genotype frequencies were 52, 44.0, and 4.0% in patients with CAD, respectively. In patients with essential hypertension, the CC, CT, and TT genotype frequencies were 46.2, 41.0, and 12.8%, respectively. In control subjects, the CC, CT, and TT genotype frequencies were 72.0, 26.0, and 2.0%, respectively. The C allele was significantly more frequent in controls compared with patients with EH (p<0.05), and CC genotypes were more frequent in controls compared to patients with EH and CAD. Homocysteine level was higher in TT genotypes in CAD patients compared with CC and CT genotypes (p<0.01). MTHFR gene polymorphism is an independent risk factor for EH but not for CAD.

CONCLUSIONS

The TT genotype of the 677C/T MTHFR polymorphism is associated with EH and CAD. In addition, TT genotypes had higher plasma Hcy levels in CAD patients compared with CC and CT genotypes. MTHFR gene polymorphism is an independent risk factor for EH but not for CAD.

Plasma homocysteine and polycystic ovary syndrome: the missed link

OBJECTIVE

The objective was to investigate the relationship between insulin resistance and increased serum homocysteine in women with polycystic ovarian syndrome (PCOS).

DESIGN

Prospective controlled trial.

SETTING

Department of Obstetrics & Gynecology, Mansoura Faculty of Medicine, Mansoura, Egypt.

PATIENTS

Ninety PCOS women as a study group and 35 women with infertility due to other causes as a control group.

OUTCOME MEASURES

Serum homocysteine levels in the presence and absence of insulin resistance in PCOS patients.

RESULTS

Homocysteine levels were significantly higher in PCOS patients than in the controls. Considering 11 micromol/l as the cut-off level for a normal homocysteine level, 41.1% of PCOS patients (37 out of 90) and 2.9% of control group (1 out of 35) had high homocysteine levels. With regard to insulin resistance, 23% of PCOS patients without insulin resistance (9 out of 39) had a high homocysteine level, while 47% of PCOS patients with insulin resistance (24 out of 51) had this, thus demonstrating the effect of insulin resistance on the homocysteine level.

CONCLUSION

There is a strong association between serum homocysteine and insulin resistance in women with PCOS that contributes to the long-term complications of PCOS.

Hyperhomocysteinemia and cardiovascular risk in postmenopausal women: the role of folate supplementation

In the postmenopausal period, cardiovascular diseases are a frequent chronic condition leading to high risk of myocardial infarction and death. Recently hyperhomocysteinemia and even mildly elevated plasma concentrations of homocysteine have been recognized as independent risk factors for vascular damage predisposing to arteriosclerosis. Elevated plasma levels of homocysteine induce vascular endothelial damage and are frequently associated with low folate levels.

In this review we evaluate literature data on some aspects related to menopause and homocysteine metabolism. In particular, we show the effect of folic acid supplementation on homocysteine concentrations and on homocysteine-related thiols, such as cysteine and cysteine-glycine, as well as the relationship with glucose, insulin, and lipidic metabolism in postmenopausal women. We also analyze the influence of folate supplementation on endothelial function, by brachial artery flow-mediated dilatation (endothelium-dependent) and nitroglycerine-induced dilatation (endothelium-independent) before and after a methionine load.

Folate administration in postmenopausal women is able to reduce high plasma homocysteine levels and to modify impaired endothelial function induced by hyperhomocysteinemia.

Clin Chem Lab Med 2007;45:130–5.

Mild hyperhomocysteinemia and the common C677T polymorphism of methylene tetrahydrofolate reductase gene are not associated with the metabolic syndrome in Type 2 diabetes

A moderate increase of total homocysteine (tHcy) plasma levels seems to increase cardiovascular disease (CVD) risk in Type 2 diabetic subjects, but its relationship with diabetes and insulin-resistance is still controversial. We examined whether mild hyperhomocysteinemia and its major genetic determinant would cluster with the metabolic syndrome (MS) in Type 2 diabetes. One hundred Type 2 diabetic subjects with and without MS were enrolled in the study. Fasting tHcy, vitamin B12, and folate plasma levels, insulin-resistance [assessed by homeostasis model assessment, (HOMAIR)] and the methylene tetrahydrofolate reductase (MTHFR) C677T genotype were assessed in all the participants. Geometric mean tHcy concentration and the prevalence of mild hyperhomocysteinemia, as commonly defined by tHcy >/=15 micromol/l, were comparable in diabetic subjects with and without MS, even after adjustment for age, sex, vitamin B12, folate and creatinine levels. In both groups, the MTHFR C677T genotype distribution was not significantly different from the Hardy-Weinberg equilibrium, with a TT homozygous frequency of 21% in subjects with and 18% in those without the syndrome (p=ns). tHcy plasma levels and the degree of insulin-resistance did not differ across MTHFR genotypes in both groups, even after multivariable adjustment. Overall, tHcy significantly correlated with creatinine (r=0.25; p=0.009) and trygliceride concentrations (r=0.24; p=0.02), but not with HOMAIR. At multivariate analysis, only creatinine was significantly correlated with tHcy levels (beta=0.42; p=0.001). In conclusion, hyperhomocysteinemia and the common C677T variant of MTHFR gene are not associated with MS in Type 2 diabetic subjects.

Effects of two different oral contraceptives on homocysteine metabolism in women with polycystic ovary syndrome

PURPOSE

This study was conducted to evaluate the effects of two different oral contraceptives (OCs) on homocysteine (Hcy) metabolism in 20 women with polycystic ovary syndrome (PCOS).

METHODS

Women were randomly allocated to receive either the biphasic OC containing 40/30 mug ethynylestradiol (EE)+25/125 mug desogestrel (DSG; n=10) or the monophasic OC containing 35 mug EE and 2 mg cyproterone acetate (CPA; n=10). Investigations were performed before and after 6 months of treatment. Fasting vitamin B(12), folate, Hcy and insulin sensitivity (SI), and glucose utilization independent of insulin (Sg), by the minimal model method, were evaluated.

RESULTS

Folate and vitamin B(12) were not significantly modified by either OC. EE/DSG decreased SI (2.53+/-0.35 vs. 1.68+/-0.45; p<.05), without modifying Hcy (9.54+/-0.7 micromol/L vs. 9.18+/-0.6 micromol/L). EE/CPA improved SI (1.47+/-0.38 vs. 3.27+/-0.48; p<.04) and decreased Hcy (9.8+/-1.9 micromol/L vs. 7.9+/-0.9 micromol/L; p<.05). This study indicates that in women with PCOS, EE/CPA, but not EE/DSG, improves IS and decreases fasting Hcy.

Sibutramine improves insulin sensitivity without alteration of serum adiponectin in obese subjects with Type 2 diabetes

AIM

To evaluate the effect of sibutramine on weight loss, insulin sensitivity and serum adiponectin levels in obese patients with Type 2 diabetes.

METHODS

This study is a randomized, double-blind, placebo-controlled parallel comparison study of sibutramine 15 mg/day and placebo. Forty-eight eligible obese patients with Type 2 diabetes (age between 30 and 75 years with body mass index > or = 27 kg/m(2)) were randomly assigned to receive either placebo (n = 24) or sibutramine (15 mg/day) (n = 24) for 6 months. Fifteen subjects in each group underwent meal tests and modified insulin suppression tests before and after 6 months' treatment.

RESULTS

After 6 months of sibutramine treatment statistically significant changes from baseline were observed for body weight (85.4 +/- 2.5 vs. 82.9 +/- 2.4 kg, P < 0.005) and body mass index (32.0 +/- 0.7 vs. 31.4 +/- 0.6 kg/m(2), P < 0.05) without a significant alteration of waist-hip ratio (W/H), blood pressure, heart rate, glycaemic parameters or lipid profiles. The steady-state plasma glucose (SSPG) level during the modified insulin suppression test was significantly reduced in the sibutramine group (17.33 +/- 2.92 vs. 14.29 +/- 4.19 mmol/l, P < 0.05) despite similar steady-state plasma insulin (SSPI) concentrations. In addition, serum adiponectin and C-reactive protein (CRP) levels remained unchanged, although modest weight reduction was achieved after sibutramine treatment. There were also no significant correlations between changes in serum adiponectin and reduction of SSPG or body weight. Daily ambient plasma insulin and glucose concentrations in response to a test meal were not significantly different in subjects receiving sibutramine treatment.

CONCLUSIONS

We conclude that treatment with sibutramine 15 mg once daily effectively reduces weight and enhances insulin sensitivity without alteration of serum adiponectin levels in obese patients with Type 2 diabetes.

Beta blocker effects on plasma homocysteine levels in patients with hypertension

Recent studies have shown that hyperhomocysteinemia might play a role in the pathogenesis of hypertension. The effects of antihypertensive agents on plasma homocysteine levels have not been tested extensively. We investigated the effects of beta-blocker therapy on homocysteine levels in patients with hypertension. In the study, 120 patients with newly diagnosed hypertension were enrolled. All patients received metoprolol succinate 100 mg/day initially. If blood pressure was above normal on the 15th day of follow-up, the metoprolol dosage was doubled. Before initiation of the antihypertensive medication and after the fourth month of treatment, homocysteine levels were measured. Of the 120 patients enrolled, 39 could not complete the study. Homocysteine levels decreased significantly by the end of the fourth month when compared with basal values (13.5+/-4.5 micromol/l versus 12.4+/-4.9 micromol/l; P = 0.001). There was no relation between homocysteine level and blood pressure control. There was a significant decrease in homocysteine levels in the women treated in this study (P = 0.001); however, this effect was absent in men (P = 0.185). We demonstrate that metoprolol succinate treatment significantly decreases plasma homocysteine levels in patients with hypertension, especially in women.

L-folic acid supplementation in healthy postmenopausal women: effect on homocysteine and glycolipid metabolism

CONTEXT

Hyperhomocysteinemia as well as alterations of glycemic and lipidic metabolism are recognized as risk factors for cardiovascular diseases.

OBJECTIVE

The aim of this study was to examine the effect of L-folic acid supplementation on homocysteine (Hcy) and related thiols, such as cysteine (Cys) and Cys-glycine (Cys-Glyc) pathways and their relationship to glucose, insulin, and lipidic metabolism in normoinsulinemic postmenopausal women.

DESIGN

This study was a randomized placebo, not double-blind, trial.

SETTING

The study was performed in an academic research center.

PATIENTS OR OTHER PARTICIPANTS

Twenty healthy postmenopausal women were selected. No patient was taking drugs known to affect lipid or glucose metabolism.

INTERVENTION(S)

Patients underwent two hospitalizations before and after 8 wk of L-acid folic (7.5 mg/d) or placebo administration. The glycemic metabolism was studied by an oral glucose tolerance test and a hyperinsulinemic euglycemic clamp. Hcy metabolism was studied by a standardized oral methionine-loading test.

MAIN OUTCOME MEASURE(S)

Hcy, Cys, and Cys-Glyc, basally and after a methionine loading test, were measured. Basal insulin, glucose, and peptide C levels as well as area under the curve for insulin, area under the curve for peptide, hepatic insulin extraction, and metabolic index were assayed. The total cholesterol, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol levels and the cholesterol/HDL and LDL/HDL ratios were also measured.

RESULTS

The total basal Hcy concentration and the plasma postmethionine loading Hcy values were significantly decreased (P < 0.01) in L-folic acid-treated patients, whereas postmethionine loading Cys-Glyc levels were markedly increased (P < 0.02). Furthermore, L-folic acid intake induced a significant improvement in carbohydrate metabolism through an increase in fractional hepatic insulin extraction (P < 0.05) and peripheral insulin sensitivity (P < 0.02) in normoinsulinemic women. HDL levels considerably increased, inducing an improvement in other atherosclerotic indexes, such as cholesterol/HDL and LDL/HDL ratios (P < 0.03).

CONCLUSIONS

These results show that folic acid supplementation lowers plasma Hcy levels and improves insulin and lipid metabolism, reducing the risk of cardiovascular disease.

Prospective evaluation of folic acid supplementation on plasma homocysteine concentrations during weight reduction: a randomized, double-blinded, placebo-controlled study in obese women

Elevated total homocysteine concentrations and obesity are both associated with an increased risk of cardiovascular disease. However, previous studies of weight reduction on serum homocysteine concentrations have obtained inconsistent reports. We investigated the effect of folic acid supplementation on serum homocysteine concentrations via a randomized, double-blinded, placebo-controlled study. Seventy-four obese women [age (mean +/- SEM) 41 +/- 1 years; body mass index, 29.6 +/- 0.5 kgs/m2] completed a 12 weeks weight reduction program with dietary advice and light exercise. They were also randomized to take either folic acid supplementation (5 mg daily, n = 36) or placebo (n = 38) groups. This program led to a weight reduction of 7.7% and 8.9% of initial weight for folic acid supplementation and placebo groups, respectively. Serum folate concentrations increased for 3 folds (p < 0.001) in the folic acid group. In the folic acid group, there was a trend of lower fasting serum homocysteine concentrations (7.6 +/- 0.2 vs. 7.3 +/- 0.3 micromol/L), but it did not reach statistical significance (p = 0.170). However, we found that serum homocysteine concentrations decreased significantly in those with higher baseline homocysteine concentrations (8.7 +/- 1.3 vs. 7.8 +/- 1.5 micromol/L, p = 0.004), while it did not change in those with lower baseline homocysteine concentrations (6.6 +/- 0.6 vs. 6.8 +/- 1.2 micromol/L, p = 0.334). Reduction of serum homocysteine concentrations did not correlate with elevation of serum folate concentrations (p = 0.646) in obese women with higher baseline homocysteine concentrations. In conclusion, serum homocysteine concentrations can be maintained in obese women during mild to moderate weight loss. Folic acid supplementation decreased serum homocysteine concentrations in those women who had higher serum homocysteine concentrations before participating in the weight reduction program.

Metabolic effects of growth hormone therapy in an Alström syndrome patient

AIM

To investigate the metabolic effects of recombinant human growth hormone (rhGH) in an Alström syndrome patient with growth hormone deficiency.

METHODS

A 15-year-old Alström syndrome boy with growth hormone deficiency received rhGH therapy for 1 year. Biochemical parameters, including hepatic enzyme levels, lipid profiles, and insulin sensitivity, were measured. Body composition analysis and computed tomography scans of the liver were performed.

RESULTS

After 1 year of rhGH treatment, body fat mass, fat infiltration in the liver, and serum lipid profiles had all decreased. Insulin sensitivity and acanthosis nigricans improved.

CONCLUSION

rhGH therapy might have beneficial effects on body composition, liver fat content, lipid profiles, and insulin resistance in Alström syndrome patients, with improvement of the glucose homeostasis.

Relationship of homocysteine to markers of platelet and endothelial activation in "high risk" hypertensives: a substudy of the Anglo-Scandinavian Cardiac Outcomes Trial

OBJECTIVE

To examine the relationship between plasma homocysteine (HCY) and rheological, endothelial and platelet markers in "high risk" hypertensive patients.

DESIGN

Cross-sectional study.

SUBJECTS AND METHODS

A total of 165 consecutive hypertensive patients (136 male; mean age 63 years (S.D. 8)) at high risk of cardiovascular disease who screened for inclusion in the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) were studied along with 38 population normotensive healthy controls. We measured levels of plasma homocysteine [high pressure liquid chromatography (HPLC)], soluble P-selectin, a marker of platelet function, von Willebrand factor (vWF), an index of endothelial damage/dysfunction [both by ELISA] and fibrinogen (CLAUSS). The Framingham cardiovascular and cerebrovascular risk scores were calculated.

RESULTS

Hypertensives had significantly higher blood pressure (BP) [165/90(16/10) vs. 138/82(12/8) mm Hg, p<0.0001], sP-sel [54(44-67) vs. 45(35-57) ng/ml, p=0.002], vWF [133(34) vs. 110(28) IU/dl, p<0.0001], and fibrinogen [2.98(2.52-3.47) vs. 2.43(2.20-2.83)g/l, p=<0.0001]. Homocysteine were lower in our hypertensives compared with controls [8.7(6.9-11.2) vs. 10.5(8.5-13.1) micromol/l, p=0.005], but there were significant correlations between homocysteine levels and both calculated 10-year coronary heart disease risk (Spearman r=0.197, p=0.026) and stroke risk (r=0.210, p=0.018), using the Framingham equation. There was a positive correlation between plasma homocysteine and soluble P-selectin (r=0.180, p=0.025), which persisted in multiple linear regression analysis. There was no significant relationship between homocysteine and HCT, PV, or the endothelial marker, vWF.

CONCLUSION

Hypertensives demonstrate abnormalities of endothelial, platelet and rheological function. Homocysteine is related to both 10-year coronary heart disease risk and stroke risk, and is significantly correlated with soluble P-selectin, a marker of platelet activation, in hypertensives but only weakly or not at all to other thrombotic markers. Increased platelet activation as reflected by soluble P-selectin may be one mechanism by which hyperhomocysteinaemia confers an increased thrombotic risk in hypertension.

Genetic influences on blood pressure within the Stanislas Cohort

OBJECTIVE

To investigate the association of 21 polymorphisms within 13 genes, APOE, APOB, APOC3, CETP, LPL, PON1, MTHFR, FGB, F5, GPIIIa, SELE, ACE and AGT, with inter-individual blood pressure (BP) variation.

PARTICIPANTS

Seven hundred and seventy-six men and 836 women, free of antihypertensive and lipid-lowering medications, were selected from the Stanislas Cohort.

RESULTS

ANOVA on blood pressure values after adjustment for covariates [age, body mass index (BMI), contraceptive pill, tobacco and alcohol] showed that lipoprotein lipase (LPL) Ser447Ter and glycoprotein IIIA (GpIIIa) Pl polymorphisms were significantly associated with BP in women (0.01 < or = P < or = 0.05), whereas BP levels in men were significantly different according to apolipoprotein CIII (APOC3) 3206T/G and -482C/T polymorphisms (P < or = 0.05). In women, compared to the most common allele, the GpIIIa Pl allele was associated with increased mean arterial pressure (MAP) (P < 0.05) and pulse pressure (PP) (P < 0.001), and the LPL 447Ter allele was associated with decreased systolic blood pressure (SBP) and PP levels (0.001 < or = P < or = 0.05). These two polymorphisms appeared to act independently. In men, the APOC3 3206GG genotype was related to decreased diastolic blood pressure (DBP) and MAP levels (P < or = 0.01), and the APOC3 -482T allele with decreased PP levels (P < or = 0.05). The presence of both the -482C allele and the 3206GG genotype was related to decreased DBP, suggesting that specific haplotypes might be involved.

CONCLUSION

The APOC3, LPL and GpIIIa genes were found to be associated with BP levels. The contributions of these genes, although modest, are consistent with the polygenic nature of BP levels.

Homocysteine and red blood cell glutathione as indices for middle-aged untreated essential hypertension patients

OBJECTIVE

Intracellular glutathione in its reduced state is a principal cellular biomolecule with antioxidant activity. Glutathione and homocysteine metabolism are closely associated. As both oxidative stress and hyperhomocystinemia are associated with hypertension, we assessed the relationships between these variables.

DESIGN AND SETTING

An observation-based case-control study, performed at a university teaching hospital.

PATIENTS

Middle-aged male patients with untreated uncomplicated essential hypertension (mean +/- standard deviation age 53.0 +/- 7.2 years, n = 48) before any treatment and controls with similar age distributions (age 51.6 +/- 5.5 years, n = 28) were evaluated.

METHODS

In all subjects, the plasma levels of homocysteine, lipids, creatinine, protein, and glucose were measured. Reduced and oxidized glutathione and folic acid were measured from red blood cells (RBC).

RESULTS

The hypertensive patients had decreased levels of red blood cell reduced glutathione (RBC-GSH) and increased levels of oxidized glutathione, which resulted in elevated ratio of oxidized/reduced glutathione as compared to controls (P < 0.001). Plasma homocysteine levels were significantly higher in the hypertensive patients versus the age-matched controls (P < 0.004). In the hypertensive patients, RBC-GSH correlated inversely with systolic blood pressure, serum creatinine, protein and RBC folic acid. No correlation was detected between RBC-GSH and homocysteine. In the controls, RBC-GSH correlated inversely with homocysteine, RBC folic acid and creatinine. According to multiple regression, in the hypertensive patients RBC-GSH was related to systolic blood pressure, hemoglobin, plasma homocysteine, creatinine and protein. Such a relationship was not detected for the controls.

CONCLUSION

In untreated hypertensive patients both homocysteine and systolic blood pressure are associated with intracellular oxidative stress as determined by RBC-GSH.

A randomized, double-blind, controlled, parallel-group comparison of perindopril and candesartan in hypertensive patients with type 2 diabetes mellitus

BACKGROUND

When choosing an antihypertensive drug for patients with hypertension and diabetes mellitus (DM), the metabolic side effects, possibility of improving some metabolic parameters, and need for adequate blood pressure control must all be considered.

OBJECTIVE

The goal of this study was to compare the impacts of perindopril and candesartan on blood pressure, glucose metabolism, serum lipid profile, and metabolic parameters in patients with mild hypertension and type 2 DM during therapy and after a 1-month washout period.

METHODS

Type 2 DM patients with mild hypertension and good glucose control who were not taking hypercholesterolemic drugs were enrolled. Perindopril 4 mg QD or candesartan 16 mg QD was administered for 12 months in this randomized, double-blind, controlled, parallel-group clinical trial. Fasting plasma glucose (FPG), fasting plasma insulin (FPI), glycosylated hemoglobin, homeostasis model assessment (HOMA) index, systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, triglycerides, lipoprotein(a) (Lp[a]), plasminogen activator inhibitor 1 (PAI-1), homocysteine, body mass index (BMI), and albumin excretion rate (AER) were assessed.

RESULTS

Ninety-six patients (49 women and 47 men; mean [SD] ages, 53 [10] years [perindopril] and 55 [9] years [candesartan]) were enrolled. Mean (SD) body weight, height, and BMI were 78.2 (9.4) kg, 1.69 (0.05) m, and 27.2 (2.0) kg/m(2) in the perindopril group and 77.5 (8.6) kg, 1.70 (0.06) m, and 26.8 (2.5) kg/m(2) in the candesartan group. A significant change occurred from baseline to month 12 during treatment with perindopril in SBP and DBP (both P < 0.01), FPG (P < 0.05), FPI (P < 0.05), TC (P < 0.05), LDL-C (P < 0.05), Lp(a) (P < 0.05), PAM (P < 0.05), and AER (P < 0.05). Significant changes from baseline to month 12 occurred with candesartan in SBP and DBP (both P < 0.01) and AER (P < 0.05). The HOMA index was significantly lower at month 12 in the perindopril group than in the candesartan group (P < 0.05). When we interrupted perindopril and candesartan therapy for a 1-month washout period, changes in SBP and DBP values were significant compared with month 12 in both groups (all P < 0.05). Changes in TC and LDL-C from month 12 to the end of washout were significant only in the perindopril group (both P < 0.05).

CONCLUSIONS

Perindopril and candesartan both effectively lowered blood pressure in this group of patients with mild hypertension and type 2 DM. Perindopril showed an improvement on some metabolic parameters compared with candesartan. However, the inclusion/exclusion criteria could limit the ability to extrapolate the results to a general population.

Plasma homocysteine levels in obese and non-obese subjects with or without hypertension; its relationship with oxidative stress and copper

OBJECTIVES

The relationship between plasma total Homocysteine (tHcy) and oxidative stress and plasma levels of lipids, insulin and copper levels were investigated in obese and nonobese hypertensives.

DESIGN AND METHODS

Plasma tHcy levels were determined by an enzyme immunoassay method. Plasma lipid peroxidation levels were measured as thiobarbituric acid reactive substances (TBARS) by spectrophotometric methods. Plasma levels of copper and insulin were measured by atomic absorption spectrophotometer and electrochemiluminescence method, respectively.

RESULTS

Plasma tHcy, copper and insulin levels did not differ in nonobese hypertensives compared to nonobese normotensives. Plasma TBARS levels were significantly increased in nonobese hypertensives when compared to nonobese normotensives (p < 0.001). Plasma tHcy, TBARS, copper and fasting insulin levels were significantly higher in obese normotensives and hypertensives than in nonobese normotensives and hypertensives, respectively (for each comparison; p < 0.001). There was a significant difference in plasma tHcy, TBARS and copper levels between obese subjects with or without hypertension (for each comparison p < 0.01). The univariate analyses demonstrated a significant positive correlation between tHcy and TBARS (coefficient +/- SE, 0.411 +/- 0.115, p < 0.01) and copper (coefficient +/- SE, 0.425 +/- 0.135, p < 0.01) in obese subjects. In a multivariate regression analysis in obese subjects tHcy was positively correlated with TBARS (coefficient +/- SE, 0.480 +/- 0.155, p < 0.01) and copper (coefficient +/- SE, 0.486 +/- 0.140, p < 0.01).

CONCLUSIONS

We hypothesize that in the presence of other traditional risk factors, Hcy may have a permissive role in the endothelium damage even within the normal range and this role may be related to free radical generating systems. Therefore, modest elevation of plasma Hcy may causally be involved in the pathogenesis of atherosclerosis and/or cardiovascular disease.

Serum homocysteine levels are increased in women with gestational diabetes mellitus

Serum homocysteine (sHcy) has been found to be elevated in patients with type 2 diabetes mellitus, as well as in other clinical conditions associated with insulin resistance and/or vascular diseases. The aims of this study were to measure the relationship between sHcy with biohumoral markers of insulin resistance in pregnant women affected with gestational diabetes mellitus (GDM). We studied 2 groups of pregnant women categorized, after a 100-g, 3-hour oral glucose tolerance test (OGTT) as nondiabetic (n = 78) or affected with GDM (n = 15), by measuring sHcy, serum folate, albumin, vitamin B(12), uric acid, and lipids. In both groups, peripheral insulin sensitivity was measured by using the OGTT-derived index of Matsuda and DeFronzo (ISI(OGTT)). Serum homocysteine was significantly higher in the group with GDM compared with nondiabetic women (5.88 +/- 2.26 micromol/L v 4.45 +/- 1.52 micromol/L; P =.003); was inversely related to serum folate (r = -.48; P =.0001), and was significantly related to serum albumin (r =.27; P =.009), 2-hour plasma glucose (r =.25; P =.01), as well as to serum uric acid (r =.23; P =.03). No relationship was observed between sHcy and serum vitamin B(12), serum triglycerides, total, or high-density lipoprotein (HDL) cholesterol, mean blood pressure and ISI(OGTT). Vitamin B(12) was correlated with ISI(OGTT) (r =.36; P =.0005) and inversely with mean blood pressure (r = -.24; P =.02). GDM remained significantly associated with higher sHcy concentrations also after adjusting for age, serum folate, albumin, uric acid, ISI(OGTT), and vitamin B(12) (P =.006). In conclusion, we found that sHcy is significantly increased in women with GDM, independently of other confounding variables, is significantly related to 2-hour OGTT plasma glucose, and seems unrelated to insulin resistance in these subjects.

The effect of methylenetetrahydrofolate reductase C677T common variant on hypertensive risk is not solely explained by increased plasma homocysteine values

The C677T transition of methylenetetrahydrofolate reductase (MTHFR) gene causes a moderate increase in total plasma homocysteine (tHcy). We studied the effect of MTHFR TT homozygosity and mild hyperhomocysteinemia on arterial hypertension. Normotensive controls (n = 223) and hypertensive subjects (n = 235) were matched for age, gender, and history of cardiovascular disease. Homocysteine levels were measured by a polarization immunoassay method. Methylenetetrahydrofolate reductase we determined by polymerase chain reaction and restriction fragment analysis. Hypertensives showed elevated tHcy compared to normotensive group in men (P = 0.039). Homocysteine values higher than 15 micromol/L were associated with increased hypertensive risk in the male population [odds ratios (OR) = 1.63; 95% confidence interval (CI) = 1.06-2.52; P = 0.027]. In multivariate analysis, TT genotype was associated with an increased risk of hypertension in males (OR = 2.27; 95% CI = 1.12-4.60; P = 0.022) An increased hypertensive risk was observed in those TT males with tHcy levels higher than 15 micromol/L (OR = 2.78; 95% CI = 1.05-7.3; P = 0.032) but not in those non-TT males with tHcy levels higher than 15 micromol/L (P = 0.33). Our findings do not support the possibility that mild hyperhomocysteinemia my solely account for the hypertensive risk associated to the TT genotype.

Insulin sensitivity and plasma homocysteine concentrations in non-diabetic obese and normal weight subjects

OBJECTIVE

To determine whether plasma homocysteine (tHcy) levels were related to insulin resistance and obesity in subjects without diabetes or vascular disease.

RESEARCH DESIGN AND METHODS

We studied correlates of plasma tHcy in 26 subjects covering a wide spectrum of obesity and insulin sensitivity (S(I)). The measurement of in vivo insulin sensitivity was performed using the minimal model analysis of the frequently sampled intravenous glucose tolerance test (FSIVGTT).

RESULTS

There was no relationship between tHcy and body mass index. There was a significant relationship between plasma tHcy and S(I) (r=0.53, P=0.006), demonstrating that the more insulin sensitive subjects had higher levels of tHcy. On log transformation of the plasma insulin values, log insulin correlated negatively with plasma tHcy (r=-0.47; P=0.02). None of the subjects were deficient in vitamin B(12) and folate. Plasma vitamin B(12) was significantly related to plasma tHcy (r=-0.44, P=0.017), although we found no significant relationship between plasma folate and tHcy (r=-0.21, P=0.27). S(I) correlated significantly with vitamin B(12) (r=0.4, P=0.045) whereas, we found no significant relationship between S(I) and plasma folate (r=0.27, P=0.2). On multiple linear regression using tHcy as the dependent variable, S(I) and vitamin B(12) remained significant predictors of plasma tHcy, whereas, age and plasma folate were not predictors of tHcy.

CONCLUSIONS

We conclude that in vitamin replete lean and obese individuals, insulin sensitivity correlates significantly with plasma tHcy. This relationship may need to be considered when evaluating the role of plasma homocysteine as a risk factor in patients with obesity and type 2 diabetes.

Circulating homocysteine levels in sustained and white coat hypertension

Although white coat hypertension has been widely studied in the last years, its risk profile is not yet completely clear. The aim of this study was to evaluate circulating homocysteine levels, an emerging cardiovascular risk factor, in subjects with white coat and sustained hypertension. We selected 31 sustained hypertensive subjects, 31 white coat hypertensive subjects and 31 normotensive subjects matched for age, gender, body mass index and occupation. Women were also matched for menopausal status. Subjects with smoking habit, dyslipidaemia and diabetes mellitus were excluded from the study. White coat hypertension was defined as clinical hypertension and daytime ambulatory blood pressure <135/85 mmHg. Blood samples were drawn after a fasting period of 12 h for routine laboratory tests and homocysteine determination. Homocysteine levels were evaluated by fluorescence polarization immunoassay. Creatinine, glucose, cholesterol and triglycerides were not different among the groups. White coat hypertensive subjects had significantly lower homocysteine levels than sustained hypertensive patients (8.2+/-2.0 vs 12.6+/-3.9 micromol/l, P=0.0003). No significant difference was observed between white coat hypertensive and normotensive subjects regarding this parameter (8.2+/-2.0 vs 7.6+/-1.9 micromol/l, P=0.9). In conclusion, our data show that middle-aged white coat hypertensive subjects without other cardiovascular risk factors have lower circulating homocysteine levels than sustained hypertensive patients suggesting that they are at lower cardiovascular risk.

Homocysteine and blood pressure

Several studies, some population-based, have linked plasma homocysteine levels to blood pressure, especially systolic pressure. The strength of this association is weak, but may be underestimated due to inaccurate blood pressure measurements. In addition, the association may be confounded by renal function. Observations that homocysteine-lowering therapies with folic acid-based treatments have been followed by decreases in blood pressure, however, raise the possibility that the link between homocysteine and blood pressure is real, which is important as homocysteine levels can easily be lowered by folic acid-based regimens. Mechanisms that could explain the relationship between homocysteine and blood pressure include increased arterial stiffness, endothelial dysfunction with decreased availability of nitric oxide, low folate status, and insulin resistance. So far, however, no evidence has been provided that these mechanisms are operative in humans. Ongoing large intervention studies with homocysteine-lowering vitamins may indicate whether blood pressure is indeed lowered by these vitamins, whether the blood pressure decrease, if any, is explained by the decrease in homocysteine levels, and whether a vitamin treatment-associated decrease in cardiovascular morbidity (if any) is explained by the decrease in blood pressure.

Plasma Homocysteine Levels in Patients With Early Coronary Artery Stenosis and High Risk Factors

The aim of this study was to study the relationship between plasma homocysteine (Hcy), folic acid, vitamin B12 and early coronary artery disease (early-CAD) and high coronary risk factors. The plasma Hcy levels of 58 cases with early-CAD and 31 subjects without CAD were measured using high-performance liquid chromatography (HPLC) with fluorescence detection. Plasma folic acid and Vitamin B12 levels were measured with radioassay method. The plasma Hcy level was significantly higher in the early-CAD patients than in the controls [(13.7 +/- 5.1) micromol/L vs (10.3 +/- 5.7) micromol/L]. The plasma folic acid and Vitamin B12 levels were significantly lower in the early-CAD patients than in the controls. The plasma Hcy level was higher in patients with more than 3 risk factors of CAD than in patients with 1 or 2 risk factors and in the controls [(17.3 +/- 5.1) micromol/ L vs (12.9 +/- 4.8) micromol/L, (7.8 +/- 2.5) micromol/L]. Other than gender, all classical coronary risk factors were related to the elevated Hcy level. Hcy levels were elevated in patients with early-CAD and with high risk factors. Hyperhomocysteinemia plays an important role in the pathogenesis of CAD.

Methylenetetrahydrofolate reductase polymorphism, type II diabetes mellitus, coronary artery disease, and essential hypertension in the Czech population

Increased plasma concentrations of homocysteine have been found in patients with coronary artery disease (CAD) and essential hypertension (EH) and in patients with diabetic complications. The 677C/T methylenetetrahydrofolate reductase (MTHFR) gene polymorphism is related to the MTHFR enzyme activity and to the plasma homocysteine concentration. This study was designed to investigate an association of this polymorphism with CAD, EH, and type II diabetes mellitus in the Czech population. The MTHFR genotypes were assessed by the polymerase chain reaction-based methodology in a sample of 1199 unrelated Caucasian subjects with CAD, EH, type II diabetes, or a combination of these diseases, and in healthy subjects. Allele frequencies of the MTHFR polymorphism differed considerably between women with and without type II diabetes mellitus (P = 0.00069), with a higher frequency of the C allele in the diabetic women. In addition, the MTHFR T allele frequency was significantly higher in normotensive subjects with CAD compared with normotensive subjects without this disease (P = 0.020). Both associations were confirmed by multiple logistic regressions. In conclusion, while the C allele of the 677C/T MTHFR polymorphism is associated with type II diabetes mellitus in women, the T allele is associated with CAD only in normotensive subjects of Czech origin.