Circulating homocysteine levels in sustained and white coat hypertension.
ABSTRACT 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.
[show abstract] [hide abstract]
ABSTRACT: 1. This review examines the current evidence for altered mechanical and circulating biomarkers in isolated clinic hypertension and their potential significance. 2. Arterial stiffness, as assessed by central pulse wave velocity, is influenced by multiple cardiovascular risk factors; however, an independent association with isolated clinic hypertension (ICHT) has not been convincingly shown in four small studies. 3. Endothelial dysfunction, as assessed by brachial artery flow-mediated vasodilation, circulating levels of endothelial markers (e.g. nitrite/nitrate, von Willebrand factor, endothelin-1) and/or circulating levels of inhibitors of vascular nitric oxide (plasma asymmetric dimethylarginine, homocysteine), has been shown to be present in established hypertension and to a variable and inconsistent extent in subjects with ICHT. 4. Evidence of increased oxidative stress in ICHT versus normotensive subjects was found in two of three studies. 5. Circulating inflammatory markers C-reactive protein and plasminogen activator inhibitor-1 were significantly increased in two of three and two of two studies, respectively, in ICHT compared with normotensive subjects. 6. Urinary albumin excretion is a marker of both arterial and renal disease. The consensus from seven studies in patients with ICHT is that albuminuria is not an independent marker for ICHT. 7. Studies to date assessing biomarkers in ICHT have been small and cross-sectional. Larger, long-term longitudinal studies of arterial functional and circulating biomarkers are required to assess the potential vascular impact of ICHT.Clinical and Experimental Pharmacology and Physiology 05/2008; 35(4):402-8. · 1.85 Impact Factor
Article: Single nucleotide polymorphism in CTH associated with variation in plasma homocysteine concentration.[show abstract] [hide abstract]
ABSTRACT: Plasma total homocysteine (tHcy) concentration, an independent risk factor of atherosclerosis, has numerous genetic and environmental determinants. While the thermolabile polymorphism in MTHFR encoding methylenetetrahydrofolate reductase is the best-studied genetic factor associated with variation in plasma tHCy, other candidate genes are being evaluated. Recently, we discovered that cystathioninuria was caused by mutations in the CTH gene encoding cystathionine gamma-lyase, an enzyme that converts cystathionine to cysteine in the trans-sulfuration pathway. We also identified a common single nucleotide polymorphism (SNP), namely c.1364G>T (S403I) in exon 12 of CTH. In the current analysis, we studied the association of genotypes of this SNP with plasma tHcy concentrations in 496 Caucasian subjects. CTH 1364T/T homozygotes had significantly higher mean plasma tHcy concentration than subjects with other genotypes, and the effect sizes of CTH and MTHFR genotypes were similar. The findings suggest that common variation in CTH may be a determinant of plasma tHcy concentrations.Clinical Genetics 07/2004; 65(6):483-6. · 3.13 Impact Factor