Relationship between the methylenetetrahydrofolate reductase (MTHFR) rs1801133 SNP and serum homocysteine levels of Zhuang hypertensive patients in the central region of Guangxi

Relationship between MTHFR, MTRR gene polymorphisms and H-type hypertension: a systematic review and meta-analysis

CONTEXT

The relationship between methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) gene polymorphisms and H-type hypertension susceptibility has been deeply analysed, but the conclusions are not consistent. Therefore, we carried out a meta-analysis aimed at assessing the relationship exactly.

METHODS

Six English databases (PubMed, Embase, EBSCO, ScienceDirect, Cochrane Library, and Web of Science) and four Chinese databases (China Biological Medicine, WanFang, China Science and Technology Journal, and China National Knowledge Infrastructure) were used for searching studies from inception to August 2023. MTHFR C677T/A1298C and MTRR A66G genetic polymorphisms were evaluated.

RESULTS

A total of 24 papers were included in our research, including 3649 H-type hyperpietics, 2772 non-H-type hyperpietics, and 2149 healthy controls. Our analysis shows that MTHFR C677T polymorphism showed significant association with H-type hypertension in both healthy individuals and non-H-type hyperpietics (TT vs. CC: OR = 3.43, 95% CI = 2.48-4.75). Further subgroup analysis based on geography revealed that homocysteine levels in the southern Chinese population were more susceptible to MTHFR C677T polymorphism (p < 0.05). However, there was no significant association in all genetic models for the polymorphisms of MTHFR A1298C and MTRR A66G.

CONCLUSION

MTHFR C677T polymorphisms are associated with H-type hypertension in non-H-type hyperpietics and healthy individuals.

Effects of Sjogren's Syndrome on essential hypertension: a two-sample mendelian randomization study

BACKGROUND

Sjogren's Syndrome (SS) plays important roles in the development of essential hypertension. Nevertheless, with the limitation of reverse causality and confounder in observational studies, such a relationship remains unclear. We aimed to assess the causal relationship of SS and hypertension by the Mendelian randomization (MR) approach.

METHODS

We used MR to investigate a causal association between SS and essential hypertension. Inverse variance weighted (IVW), MR Egger regression, Maximum likelihood, Weighted median, and MR pleiotropy residual sum and outlier test (MR-PRESSO) were used in this MR analysis.

RESULTS

In this study, we found that the ratio of IVW is 1.00024 (95% CI: 1.00013- 1.00036, P=0.0387), This result was also confirmed by sensitivity analysis methods such as Maximum likelihood is 1.00025 (95% CI: 1.00013-1.00037, P=0.036), MR Egger is 1.00071 (95% CI: 1.00047-1.00095, P=0.0045), and Weighted median is 1.00040 (95% CI: 1.00021- 1.00059, P=0.0322). And MR-Egger intercept method revealed the absence of horizontal pleiotropy in this investigation (P>0.05). The Cochran's Q Test indicated an absence of heterogeneity among them (P>0.05). Heterogeneity and horizontal pleiotropy tests further demonstrate that the results of MR are relatively stable. The above results all suggest that pSS may promote the risk of hypertension.

CONCLUSIONS

Our study provides evidence of a causal relationship of SS and hypertension. It is suggested to pay attention to early screening for hypertension, reduce disability and mortality rates, and improve patient prognosis in patients with SS.

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.