Background and Purpose—: Elevated blood homocysteine concentration increases the risk of stroke, especially among hypertensive individuals. Homocysteine is largely affected by the methylenetetrahydrofolate reductase C677T polymorphism and folate status. Among hypertensive patients, we aimed to test the hypothesis that the association between homocysteine and stroke can be modified by the methylenetetrahydrofolate reductase C677T polymorphism and folic acid intervention. Methods—: We analyzed the data of 20 424 hypertensive adults enrolled in the China Stroke Primary Prevention Trial. The participants, first stratified by methylenetetrahydrofolate reductase genotype, were randomly assigned to receive double-blind treatments of 10-mg enalapril and 0.8-mg folic acid or 10-mg enalapril only. The participants were followed up for a median of 4.5 years. Results—: In the control group, baseline log-transformed homocysteine was associated with an increased risk of first stroke among participants with the CC/CT genotype (hazard ratio, 3.1; 1.1–9.2), but not among participants with the TT genotype (hazard ratio, 0.7; 0.2–2.1), indicating a significant gene–homocysteine interaction ( P =0.008). In the folic acid intervention group, homocysteine showed no significant effect on stroke regardless of genotype. Consistently, folic acid intervention significantly reduced stroke risk in participants with CC/CT genotypes and high homocysteine levels (tertile 3; hazard ratio, 0.73; 0.55–0.97). Conclusions—: In Chinese hypertensive patients, the effect of homocysteine on the first stroke was significantly modified by the methylenetetrahydrofolate reductase C677T genotype and folic acid supplementation. Such information may help to more precisely predict stroke risk and develop folic acid interventions tailored to individual genetic background and nutritional status. Clinical Trial Registration—: URL: http://www.clinicaltrials.gov . Unique identifier: NCT00794885.

Objective: To examine the efficacy and effect modifiers of folic acid supplementation in the prevention of stroke in regions without folic acid fortification based on relevant, up-to-date published randomized trials. Methods: Relative risk (RR) was used to measure the effect of folic acid supplementation on risk of stroke using a fixed effects model. Findings: Overall, folic acid supplementation significantly reduced the stroke risk by 11% (22 trials, n = 82,723; RR 0.89, 95% confidence interval [CI] 0.84–0.96). The effect was greater in low folate regions (2 trials, n = 24,020; Asia, 0.78, 0.67–0.90) compared to high folate regions (7 trials, n = 14,655; America, 1.05, 0.90–1.23), and among patients without folic acid fortification (11 trials, n = 49,957; 0.85; 0.77–0.94) compared with those with folic acid fortification (7 trials, n = 14,655; 1.05, 0.90–1.23). In further stratified analyses among trials without folic acid fortification, a larger beneficial effect was found in those trials that used a low dosage of folic acid (≤0.8 mg: 0.78, 0.69–0.88) or low baseline vitamin B₁₂ levels (<384 pg/mL: 0.78, 0.68–0.89). In the corresponding comparison groups, the effect sizes were attenuated and insignificant (p for interaction <0.05 for both). Although the interaction tests were not significant, there might be a higher benefit in trials with a low dosage of vitamin B₁₂, a low prevalence of statin use, but a high prevalence of hypertension. Conclusions: Folic acid supplementation could reduce the stroke risk in regions without folic acid fortification, particularly in trials using a relatively low dosage of folic acid and with low vitamin B₁₂ levels.

Vascular dementia (VaD), the second cause of dementia, is caused by chronic cerebral hypoperfusion, producing progressive damage to cerebral cortex, hippocampus, and white matter. Ligustilide (LIG), one of the main active ingredients of Angelica sinensis, exerts the neuroprotective effect on neurodegenerative diseases. However, the mechanism remains unclear. An in vivo model of bilateral common carotid artery occlusion and in vitro model of oxygen glucose deprivation (OGD) were employed in this study. LIG (20 or 40 mg/kg/day) was intragastrically administered to the VaD rats for four weeks. The results of the Morris water maze test demonstrated that LIG effectively ameliorated learning and memory deficiency in VaD rats. LIG obviously relieved neuronal oxidative stress damage by increasing the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH‐PX) and decreasing the level of malondialdehyde (MDA) in VaD rats. Nissl staining showed that LIG increased the number of the Nissl body in VaD rats. After LIG administration, the apoptotic‐related protein, Bax, was decreased and Bcl‐2 was increased in the hippocampus of VaD rats. Moreover, the expressions of sirtuin 1 (SIRT1) and protein disulfide isomerase (PDI) were decreased, binding immunoglobulin protein (BIP) and phospho‐inositol‐requiring enzyme‐1α (P‐IRE1α), X‐box binding protein 1 (XBP1s), and C/EBP‐homologous protein (CHOP) were increased in VaD rats. After LIG treatment, these changes were reversed. The immunofluorescence results further showed that LIG upregulated the expression of SIRT1 and downregulated the expression of P‐IRE1α in VaD rats. In addition, in vitro experiment showed that EX‐527 (SIRT1 inhibitor) partly abolished the inhibitory effect of LIG on the IRE1α/XBP1s/CHOP pathway. In conclusion, these studies indicated that LIG could improve cognitive impairment by regulating the SIRT1/IRE1α/XBP1s/CHOP pathway in VaD rats.