Studies on homocysteine demonstrating its significance as a possible tool for differential diagnosis in occlusive vascular disease

A prospective cohort study of MTHFR C677T gene polymorphism and its influence on the therapeutic effect of homocysteine in stroke patients with hyperhomocysteinemia

BACKGROUND

Hyperhomocysteinemia (HHCY) is a risk factor for cardiovascular and cerebrovascular diseases. The C677T 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphism increases homocysteine (HCY) levels. This study analyzed the relationship between C677T MTHFR polymorphism and the therapeutic effect of lowering HCY in stroke patients with HHCY.

METHODS

Baseline data were collected from stroke patients with HHCY for this prospective cohort study. The C677T MTHFR genotype was detected by polymerase chain reaction-restriction fragment length polymorphism and the therapeutic effect to reduce HCY was compared.

RESULTS

Of 200 stroke patients 162 (81.0%) completed follow-up and were evaluated. Most of them responded well to treatment (103 cases, 63.5%), but 59 (36.4%) patients were in the poor efficacy group. There was a significant difference in terms of age (P < 0.001), hypertension (P = 0.041), hyperuricemia (P = 0.042), HCY after treatment (P < 0.001), and MTHFR genotype (P < 0.001) between the poor efficacy and effective groups, with increased frequency of the TT genotype in the poor efficacy group. Logistic regression showed that the T allele was associated with poor efficacy (OR = 0.733, 95%CI: 0.693, 0.862, P < 0.001). In the codominant model the TT genotype was associated with poor outcome (OR = 0.862, 95%CI: 0.767, 0.970, P = 0.017) and this was also the case in the recessive model (OR = 0.585, 95%CI: 0.462, 0.741, P < 0.001) but there was no association between CT and TT in the dominant model.

CONCLUSIONS

The T allele and TT genotype of the MTHFR C677T polymorphism was associated with poor HCY reduction treatment efficacy in stroke patients with HHCY.

TRIAL REGISTRATION

The registration number of the clinical trial is ChiCTR1800020048. Registration date: December 12, 2018.

Homocysteine‑induced oxidative stress through TLR4/NF‑κB/DNMT1‑mediated LOX‑1 DNA methylation in endothelial cells

Atherosclerosis (AS) is a progressive disease of multifactorial origin, which occurs in response to endothelial injury. Increased homocysteine (Hcy) is considered a major cause of endothelial dysfunction, oxidative stress and DNA methylation; however, the mechanisms remain to be fully elucidated. The aim of the present study was to investigate whether Hcy causes injury to endothelial cells (ECs) by the effect of lectin‑like oxidized‑low density lipoprotein receptor‑1 (LOX‑1) DNA methylation through toll‑like receptor 4(TLR4)/nuclear factor (NF)‑κB/DNA methyltransferase (DNMT)1. The ECs were treated with different concentrations of Hcy, and it was found that Hcy promoted the expression of TLR4, leading to EC injury. The effect of oxidative stress was analyzed by measuring superoxide dismutase, malondialdehyde and hydrogen peroxide in the ECs. In addition, the association between NF‑κB and DNMT1 was examined by treatment of the ECs with pyrrolidine dithiocarbamate (PDTC). The results suggested that Hcy induced LOX‑1 DNA hypomethyaltion to promote the expression levels of LOX‑1. Taken together, Hcy injured the ECs through the effect of methylation and trans‑sulfuration metabolism of LOX‑1 through TLR4/NF‑κB/DNMT1. Following injury to the ECs, lipids, particularly ox‑LDL, accumulated in the sub‑endothelial layer to promote the formation of AS.

Homocysteine and lipoprotein (a) correlation in ischemic stroke patients

BACKGROUND

Homocysteine and Lipoprotein (a) have been recognized as risk factors for coronary heart disease. However, their role in ischemic stroke is still not defined. Therefore the present study was undertaken to evaluate their levels and relationship in patients of ischemic stroke.

METHODS

The study was conducted in consecutive patients admitted with a diagnosis of acute ischaemic stroke and age and sex matched healthy controls. Plasma homocysteine and serum l lipoprotein (a) levels were determined in the fasting venous blood samples using ELISA and immunoturbidimetric assay respectively.

RESULTS

66 patients with ischaemic stroke (30 males, 36 females) of mean age 54.43+/-1.97 years and 72 controls (39 males, 33 females) of mean age 53.86+/-1.88 years were studied. Mean plasma homocysteine levels in the stroke patients and control groups were 28.40+/-2.08 micromol/L and 11.16+/-1.09 micromol/L respectively (p<0.001). Odds ratio for raised homocysteine levels in stroke cases was 15.7. Plasma homocysteine levels showed a positive correlation with smoking (Pearson's correlation coefficient=0.324 and p-value of 0.008), (Odds ratio=5.71). Serum Lipoprotein (a) levels in stroke cases and control group were 57.33+/-4.40 mg/dl and 23.46+/-1.09 mg/dl respectively, (p<0.001), (Odds Ratio=8.62). A positive correlation was also observed between Homocysteine and Lipoprotein (a) levels with Pearson's correlation coefficient of 0.75 and p-value<0.001.

CONCLUSIONS

Raised homocysteine and serum lipoprotein (a) levels were found to be independently associated with ischemic stroke with a significant positive correlation between the two parameters. Elevated homocysteine levels may modulate the toxicity of lipoprotein (a) in ischemic stroke.