Homocysteine and atheromatous renal artery stenosis

Association between Hcy levels and the CBS844ins68 and MTHFR C677T polymorphisms with essential hypertension

The aim of the present study was to investigate the association between the homocysteine (Hcy) levels and polymorphisms of the CBS844ins68 and MTHFR C677T genes in essential hypertension (EH). The effects of the MTHFR C677T and CBS844ins68 haploid genotypes and the combined genotypes on EH and levels of Hcy were further explored. The polymorphisms of CBS844ins68 and MTHFR C677T genes in 200 EH and 200 normal tensive (NT) patients were detected using polymerase chain reaction-restriction fragment length polymorphism and analysis of the distribution of genotypes. An automated biochemical analyzer was used to measure the plasma Hcy levels and the clinical biochemistry data. The plasma Hcy levels in EH were significantly higher than those of the NT group (P<0.05). There were no significant differences (P>0.05) between males and females. Two genotypes, deletion/deletion (DD) and deletion/insertion (DI), of the CBS844ins68 polymorphism were found in two groups with no clear differences in two genotypes and allele frequency distribution (P>0.05). There were significant differences in the three genotype frequencies (χ²=6.658, χ²=4.410, P<0.05) for MTHFR C677T locus genotypes CC, CT and TT. The Hcy levels in genotypes DD and DI had no significant differences (P>0.05) and the CT and TT types were significantly higher compared to the CC genotype (P<0.05). The CC/DD combined genotype in the two groups was significantly different (P<0.05), and the odds ratio (OR), 0.569 showed that the CC/DD genotype may be a protective factor of hypertension. In the two groups, the Hcy levels for combined genotypes CC/DD, CT/DD, TT/DD and TT/DI were significantly different (P<0.05). The SHEsis software analysis linkage disequilibrium coefficient=0.216, indicates that there is probably a weak linkage for MTHFR C677T and CBS844ins68. Haplotype analysis suggested that the C-D haplotype was negatively correlated with EH (OR, 0.727) and that there was a positive correlation between T-D haplotype and EH (OR, 1.376). MTHFR C677T and CBS844ins68 polymorphisms were present in the populations studied and the CBS844ins68 homozygous mutation was not present. Therefore, there is a correlation between the polymorphisms of the MTHFR C677T gene and EH, and allele T may be one of the predisposing factors. MTHFR C677T and CBS844ins68 may exist with a certain linkage and the T-D haplotype may be a risk factor for EH.

Atherosclerotic renovascular disease in chronic heart failure: should we intervene?

Renal artery stenosis (RAS) is most commonly caused by atherosclerosis, which is also the most common cause of chronic heart failure (CHF). One-third of patients with CHF are reported to have significant renovascular disease. The presence of RAS confers a worse outcome in studies of hypertension and coronary disease, though data are lacking for patients with CHF. As the kidney is intricately involved in the fluid retention that occurs in CHF, an adverse effect of RAS on outcome would be expected. Presentations of RAS in CHF include flash pulmonary oedema, hypertension, worsening of CHF, and worsening renal function. RAS commonly progresses and may cause worsening of renal function in patients with CHF and previously stable renal function. A variety of investigations that can safely and accurately identify RAS in CHF are available, although none is recommended in current guidelines for the management of CHF. Treatment for RAS, whether for hypertension, for renal dysfunction, or for pulmonary oedema, is at the discretion of the physician due to the lack of adequate randomized controlled trials demonstrating the efficacy and safety of intervention. As it is not clear how RAS should be managed in CHF, screening cannot be advocated. Currently, a multicentre randomized outcome trial, which includes a cohort of patients with RAS and CHF, is in progress to provide answers in this area of uncertainty.

Saratin (an inhibitor of platelet-collagen interaction) decreases platelet aggregation and homocysteine-mediated postcarotid endarterectomy intimal hyperplasia in a dose-dependent manner

BACKGROUND

This study investigated Saratin's (Merck KGaA, Darmstadt, Germany) prevention of platelet adhesion and intimal hyperplasia at different doses and in the hyperhomocystinemia rat carotid endarterectomy (CEA) model.

METHODS

Rats were divided into two groups: (1) platelet adhesion or (2) luminal stenosis because of intimal hyperplasia. At CEA, rats received 0, 0.5, 5.0, 10.0, or 20.0 microg Saratin on the artery. Post-CEA platelet aggregation was evaluated by standard error of the mean. Intimal hyperplasia group received either (1) control or (2) 4.5 g/kg DL-homocystine diets for two weeks followed by CEA and treated with diluent or 5.0 microg Saratin. Endpoints included platelet adhesion, intimal hyperplasia, plasma homocysteine (HCys), and its metabolic enzymes cystathionine beta-synthase (CBS) and methylenetetrahydrofolate reductase (MTHFR).

RESULTS

Platelet adhesion: post-CEA, platelet adhesion was reduced by 63%, 67%, and 67% in Saratin doses > or =5.0 microg. Intimal hyperplasia: 5.0 microg Saratin in the HCys group decreased intimal hyperplasia by 45% compared with the non-Saratin-treated HCys group. Plasma HCys levels were not altered with Saratin treatment in the HCys groups nor were CBS or MTHFR.

CONCLUSIONS

Saratin significantly inhibited platelet adhesion at > or =5.0 microg, and Saratin at 5.0 microg attenuated luminal stenosis in a hyperhomocysteinemic rat CEA model.