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

Homocysteine, hyperhomocysteinemia, and H-type hypertension

Homocysteine (Hcy) is a sulphur-containing nonessential amino acid derived from the intermediate metabolites of methionine. Methionine is obtained from dietary proteins, such as poultry, meat, eggs, seafood, and dairy products. Abnormalities in Hcy metabolic pathways, deficiencies in dietary methionine, folate, and vitamins B12, B6, and B2 and genetic defects, polymorphisms, or mutations in Hcy metabolism-related enzymes may lead to an increase in plasma Hcy levels. Generally, a plasma Hcy level higher than 10 or 15 μmol/L has been defined as hyperhomocysteinemia (HHcy). An individual with essential hypertension complicated with HHcy is considered to have H-type hypertension (HTH). Currently, HHcy is considered a novel independent risk factor for various cardiovascular diseases. To provide a useful reference for clinicians, the research progress on Hcy, HHcy, and HTH in recent years was systematically reviewed here, with a focus on the source and metabolic pathways of Hcy, plasma Hcy levels and influencing factors, detection methods for plasma Hcy levels, relationship between Hcy concentration and hypertension, pathogenesis of HTH, cardiovascular complications of HTH, and treatment of HTH.

Relationship between MTHFR C677T, homocysteine, and ischemic stroke in a large sample of the Han Chinese population

Ischemic stroke, one of the prevalent causes of death and disability worldwide, is linked to environmental and genetic factors, including polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene involved in homocysteine metabolism. The present study aimed to explore the relationship between the MTHFR C677T variant, plasma homocysteine, and risk of developing large-artery atherosclerotic ischemic stroke (LAAIS) among Han Chinese. A population-based case-control study, which included 1810 patients with LAAIS and 1765 unrelated control subjects, was conducted. Compared to the controls, LAAIS patients had a significantly higher prevalence of hypertension, diabetes mellitus, smoking, and alcohol consumption (P < .001), as well as significantly higher mean fasting blood glucose, triglyceride, total cholesterol, and plasma homocysteine levels (P < .001). The TT homozygous genotype correlated with increased risk of developing LAAIS, as indicated by a significantly higher odds ratio (OR) compared to the CT and CC genotypes, in both additive (OR = 3.215, P = .01) and recessive models (OR = 3.265, P = .01). The plasma homocysteine level was genotype-dependent according to the following trend: TT > CT > CC. In conclusion, our data demonstrate that, in spite of its low prevalence in both patients and controls (1.5% vs 0.8%), the MTHFR C677T variant could, at least in part, affect homocysteine levels and this, either alone or in combination with other factors, increases the risk of LAAIS.

Effect of folic acid, vitamin B12, and B6 supplementation on the risk of cardiovascular and cerebrovascular diseases: An updated meta-analysis of randomized controlled trials

Background

Numerous studies indicated that B vitamin supplementation can reduce cardiovascular risk; nonetheless, available proof reported from individual studies have not been consistent, so we performed an updated meta-analysis of randomized controlled trials (RCTs) to evaluate the relationship between B vitamin supplementation and cardiovascular outcomes.

Materials and method

Relevant studies published before May 2022 were searched from the electronic databases of PubMed, Embase, the Cochrane Library, Chinese Biology Medicine, and the Chinese National Knowledge Infrastructure. Outcomes included major adverse cardiovascular event (MACE), myocardial infarction (MI), stroke, hospitalization for unstable angina, revascularization, total mortality, and cardiovascular death. The strength of the association was examined by risk ratio (RR) with 95% confidence interval (95% CI).

Results

A total of 17 RCTs involving 31,085 subjects were included in the meta-analysis. The combined supplementation of B vitamins had no significant effect on MACE based on eight RCTs (RR = 0.98, 95% CI = 0.92–1.04), MI based on 13 RCTs (RR = 1.00, 95% CI = 0.92–1.09), and revascularization based on 12 RCTs (RR = 1.02, 95% CI = 0.95–1.10). Ten studies showed that the combined supplementation of B vitamins reduced the risk of stroke by 12% (RR = 0.88, 95% CI = 0.81–0.97). Eleven studies showed that the combined supplementation of B vitamins had no significant effect on the total mortality (RR = 0.99, 95% CI = 0.94–1.05), and nine studies showed that the combined B vitamins had no significant effect on cardiovascular death (RR = 0.96, 95% CI = 0.88–1.05). Besides, with the extension of follow-up duration and those with a history of cardio-cerebrovascular diseases, supplementation of B vitamins could reduce the risk of stroke.

Conclusion

The supplementation of folic acid, Vitamin B6, and B12 is associated with a reduction in stroke, but not in total mortality, cardiovascular death, MACE, and MI.

Traditional risk factors and combined genetic markers of recurrent ischemic stroke in adults

BACKGROUND

The involvement of traditional risk factors and combined genetic markers of recurrent arterial ischemic stroke (AIS) in adults remains unclear.

OBJECTIVE

This study aims to determine significant clinical and genetic factors of AIS recurrence, and to investigate the combined effect of genotypes on the occurrence of a second cerebral ischemic attack.

METHODS

We investigated a cohort study of AIS patients (18-50 years old) followed in the neurology department over 5 years. Traditional and genetic risk factors were carried through a multivariable logistic regression model. We used a Cox proportional hazard model for identifying predictors of recurrence.

RESULTS

Two hundred and seventy patients were enrolled in our study. The risk of AIS recurrence was 36.2% within 5 years. The potential risk of recurrence of AIS increased with traditional and genetic risk factors such as hypertension, diabetes mellitus, heart failure, and family history of cerebrovascular diseases. This risk increased with increasing number of genetic factors. The hazard ratio (HR) was 0.66 (95% confidence interval [CI] 0.97-2.67) for the subject with one genetic factor, 1.61 (95% CI 0.97-2.25) for combined methylenetetrahydrofolate reductase (MTHFR) polymorphisms, and 2.57 (95% CI 1.32-4.99) for combined factor V Leiden (FVL) and MTHFR polymorphisms (677 or 1298). The HR for the three polymorphisms combined was 6.04 (95% CI 2.40-15.16).

CONCLUSIONS

Our findings suggest that cumulative effect of both traditional and common genetic risk factors was associated with recurrence of ischemic stroke. We demonstrated for the first time that a combined genotype FVL/MTHFR profile increase the risk of a second cerebral ischemic attack.

MTHFR (C677T, A1298C), FV Leiden polymorphisms, and the prothrombin G20210A mutation in arterial ischemic stroke among young tunisian adults

Arterial ischemic stroke (AIS) in young adults is less common in older adults, but the underlying pathogenesis and risk factors are more multi-faceted. The role of inherited thrombophilia such as 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphism, (C677T and A1298C), factor V of Leiden (FVL) polymorphism, and the prothrombin G20210A mutations remains unclear. This study aims to evaluate the role of prothrombin genetic factor in AIS among young adults in Tunisia and to assess the synergistic effect between thrombogenic mutations in the pathogenesis of AIS. In this case-control study, blood samples were collected from patients and healthy controls, all matched for age and gender. The difference between them is evaluated by using the chi-square test. The odds ratio (OR) was carried out to evaluate the associations between each polymorphism and AIS risk using a binary logistic regression model. Values were considered statistically significant when p < 0.05. Patients carrying simultaneously the MTHFR polymorphisms (677T and 1298C) have a higher risk to develop AIS compared to controls. The heterozygous variants FVL increased the risk of AIS only when it is associated with MTHFR C677T or MTHFR A1298C polymorphisms. In conclusion, our study confirmed the involvement of MTHFR polymorphisms as AIS's important risk factors. The existence of FVL polymorphism or prothrombin G20210A mutation alone doesn't correlate with the occurrence of stroke. We assume that the presence of both MTHFR and FVL polymorphisms has a synergistic effect and increased the risk of the AIS.