Homocysteine and carotid plaque stability: a cross-sectional study in Chinese adults

The association between hyperhomocysteinemia and the prevalence of bilateral carotid atherosclerotic plaques in a middle-aged population

OBJECTIVE

We conducted a cross-sectional study to investigate the impact of hyperhomocysteinemia (HHcy) on the prevalence of CASP among middle-aged individuals, aiming to provide insights for CASP prevention.

METHODS

1105 subjects were categorized into HHcy group or normal tHcy group based on their plasma total homocysteine (tHcy). All participants underwent carotid artery ultrasonography to assess the presence of unilateral and bilateral CASP. Comparative analyses of demographic and clinical data were conducted between the two groups. Logistic regression and prespecified subgroup analyses were performed to determine whether HHcy independently contributed to bilateral CASP.

RESULTS

132 individuals exhibited bilateral CASP. The prevalence of bilateral CASP was significantly higher in the HHcy group compared to the normal tHcy group (21.55 % vs. 10.82 %, p = 0.003). Univariate logistic analysis showed a significant association between HHcy and the prevalence of bilateral CASP (OR = 2.056, 95 %CI 1.089-3.881, p = 0.026). In all four models of multivariate logistic analysis, HHcy consistently emerged as an independent risk factor for bilateral CASP, with odd ratios of 1.958, 2.047, 2.023, and 2.186. This association remained significant across all five subgroups stratified by age, sex, hypertension, diabetes, and BMI.

CONCLUSION

Our studies demonstrated HHcy was an independent risk factor for the prevalence of bilateral CASP in the middle-aged population. Theses results emphasized the importance of addressing HHcy in preventive strategies aimed at mitigating the burden of CASP among middle-aged individuals.

Characteristics of the gut microbiota of patients with symptomatic carotid atherosclerotic plaques positive for bacterial genetic material

Background

The gut microbiota (GM) is believed to be closely associated with symptomatic carotid atherosclerosis (SCAS), yet more evidence is needed to substantiate the significant role of GM in SCAS. This study, based on the detection of bacterial DNA in carotid plaques, explores the characteristics of GM in SCAS patients with plaque bacterial genetic material positivity, aiming to provide a reference for subsequent research.

Methods

We enrolled 27 healthy individuals (NHF group) and 23 SCAS patients (PFBS group). We utilized 16S rDNA V3-V4 region gene sequencing to analyze the microbiota in fecal samples from both groups, as well as in plaque samples from the carotid bifurcation extending to the origin of the internal carotid artery in all patients.

Results

Our results indicate significant differences in the gut microbiota (GM) between SCAS patients and healthy individuals. The detection rate of bacterial DNA in plaque samples was approximately 26%. Compared to patients with negative plaques (PRSOPWNP group), those with positive plaques (PRSOPWPP group) exhibited significant alterations in their GM, particularly an upregulation of 11 bacterial genera (such as Klebsiella and Streptococcus) in the gut, which were also present in the plaques. In terms of microbial gene function prediction, pathways such as Fluorobenzoate degradation were significantly upregulated in the GM of patients with positive plaques.

Conclusion

In summary, our study is the first to identify significant alterations in the gut microbiota of patients with positive plaques, providing crucial microbial evidence for further exploration of the pathogenesis of SCAS.

Additive effect between homocysteine and low-density-lipoprotein cholesterol upon incidence of novel carotid plaque formation: data from a Chinese community-based cohort

OBJECTIVE

Homocysteine (HCY) has been associated with carotid plaque in cross-sectional studies, but the prospective relationship between HCY and incident carotid plaque has not been well established. The purpose of this study was to investigate the association between HCY and incidence of novel carotid plaque in a Chinese community-based population without pre-existing carotid atherosclerosis and to assess the additive effect of HCY and low-density lipoprotein cholesterol (LDL-C) on the incidence of novel plaque.

METHODS

At baseline, we measured HCY and other risk factors in subjects aged ≥ 40 years. All participants underwent carotid ultrasound examinations at baseline and after an average of 6.8 years of follow-up. Incidence of plaque was identified if plaque was absent at baseline, but plaque was detected at the end of follow-up. A total of 474 subjects were included in the analysis.

RESULTS

The incidence of novel carotid plaque was 24.47%. Multivariate regression analyses showed that HCY was independently associated with a 1.05-fold-higher likelihood for incident novel plaque (adjusted odds ratio [OR] = 1.05, 95% confidence interval [CI]: 1.01-1.09, P = 0.008). Using tertile 1 and tertile 2 for reference, the top HCY tertile (T3) showed a 2.28-fold-higher likelihood for incident plaque (adjusted OR = 2.28, 95%CI: 1.33-3.93, P = 0.002). The combination of HCY T3 and LDL-C ≥ 3.4 mmol/L had the highest risk for novel plaque formation (adjusted OR = 3.63, 95%CI: 1.67-7.85, P = 0.001) compared to those without either condition. In the LDL-C ≥ 3.4 mmol/L subgroup, HCY was significantly associated with incidence of plaque (adjusted OR = 1.16, 95%CI: 1.04-1.28, P = 0.005, P-interaction = 0.023).

CONCLUSION

In the Chinese community-based population, HCY was independently associated with the incidence of novel carotid plaque. There were additive effect between HCY and LDL-C on the incidence of plaque, the highest risk was observed in individuals with both high HCY levels and LDL-C ≥ 3.4 mmol/L. Our findings suggest that HCY may be a potential target for preventing the incidence of carotid plaque, particularly in individuals with elevated LDL-C levels.

Association of homocysteine with carotid atherosclerosis in hypertension

Information on the association between homocysteine (HCY) levels and carotid atherosclerosis (CAS) in hypertension (HTN) is limited. A cross-sectional study was performed to examine the relationship of plasma HCY concentration with CAS in 1700 hypertensives (61.62 ± 12.16 year). The prevalence of CAS and carotid intima-media thickness (CIMT) progressively increased across quartiles of HCY levels (P < 0.001). Correlation analysis showed significantly positive correlation between HCY and CAS (r = 0.261, P < 0.001). In a logistic regression, HCY independently predicted the presence of CAS (OR 1.284, 95% CI 1.163-1.418). Further investigation revealed that interaction effect of HCY was substantial for gender (P for interaction 0.023), age (P for interaction <0.001) and smoking (P for interaction 0.025) on CAS. Thus, in hypertensives, those of male, aged ≥55 year and current smokers, in which HCY ≥ 13.49 μmol/L were more likely to suffer CAS, suggesting a role of HCY in the development and progression of CAS in these patients, and HCY determination should be recommended to better stratify the cardiovascular risk.

Plasma Homocysteine in Patients with Coronary and Carotid Artery Disease: A Case Control Study

INTRODUCTION

Homocystein (Hcy) is an amino acid and elevated plasma cause endothelial damage, followed with inflammation in the blood vessels and its progression in atherosclerosis. We aimed to evaluate the correlation between cardiovascular disease and serum homocysteine levels..

METHODS

We performed a case control analysis of 212 patients, either for cardiovascular risk stratification or for invasive diagnostics and treatment of cardiovascular ischemic disease (CAD). Patients were divided into 4 groups: Group 1. Patients with low risk for CAD, with no symptoms of CAD and total of 10 years risk <10%. Group 2. High-risk patients with no symptoms of CAD, but 10 years total CAD risk of >20%. Group 3. Patients with symptomatic CAD, where angiography was performed and >50% occlusion of at least one coronary vessel was found. Group 4. Patients with carotid artery disease and documented CAD.

RESULTS

Group 1 consists of 56 subjects, of whom 33 (60%) males and 22 (40%) females. Their mean age was 52.18±8.07 years and their average CAD risk was 5. Group 2 included 60 patients, with average CAD risk of 23.73. There was a statistically significant difference between plasma homocysteine levels between the control and high CAD risk group, as well as between those with CAD and both CAD and CARD (p=0.001). In the high-risk subjects group, the level of homocysteine correlates albeit weak with the total CAD risk (p=0.04). Homocysteine levels correlate with the WBC count (p=0.02). In the subgroup of smokers with high CAD risk, homocysteine correlates with age, total CAD risk, total cholesterol, BUN (define BUN) and creatinine. Group 3 consisted of 49 subjects with manifested and angiographically proven CAD, out of whom 80% were males and 20% females, mean age 56.06±9.7 years, with average 2 coronary vessels affected. There were significantly higher homocysteine plasma levels between the control group and the group with manifested CAD (p=0.008).There is no significant difference of homocysteine plasma levels between the high risk group and the group with manifested coronary artery disease (15.03□mol/l vs. 16.38□mol/l). In this group, plasma levels of homocysteine correlate only with the highest level of vessel stenosis (>95%) with (p=0.04). The study population in group 4 showed a mean of IMT 0.9 +..09 mm and mean Hcy plasma levels of 21 + 11 µmol/L. From the evaluated patients with CAD, 82.9% of patients had elevated level of Hcy. From those, one showed elevated Hcy, 79.4 % had hypertension, 58.9 % had hyperlipidemia, 28.2% had diabetes mellitus as additional risk factors for atherosclerosis. 76.9 % of the patients had increased intima-media thickness; in 58.9 % plaques were detected, while 23 % of the patients had significant stenosis: 10.2 % with intermediate-grade stenosis (50-69%) and 12.8 % with high-grade stenosis (70-99 %). 17.1 % of the patients had normal level of Hcy, and in those ones 62.5 % only had increased IMT. We found linear correlation between IMT and HCy levels (r 0.7, p 0.05). Case control analysis showed significant higher level of Hcy in the group with CAD and carotid artery disease vs. CAD group (p 0.001).

CONCLUSION

High plasma homocysteine concentrations are associated with high risk for vascular disease and consequently CAD itself and carotid artery disease, as well, proving its likely role in the development of atherosclerosis on inflammatory and metabolic levels.

Hyperhomocysteinemia and dyslipidemia in point mutation G307S of cystathionine β-synthase-deficient rabbit generated using CRISPR/Cas9

Background

Congenital hyper-homocysteinemia (HHcy) is caused by a defective cystathionine β-synthase (CBS) gene, and is frequently associated with dyslipdemia. The aim of this study was to further elucidate the effect of mutated CBS gene on circulating lipids using a rabbit model harboring a homozygous G307S point mutation in CBS.

Methods

CRISPR/Cas9 system was used to edit the CBS gene in rabbit embryos. The founder rabbits were sequenced, and their plasma homocysteine (Hcy) and lipid profile were analyzed.

Results

Six CBS-knockout (CBS-KO) founder lines with biallelic modifications were obtained. Mutation in CBS caused significant growth retardation and high mortality rates within 6 weeks after birth. In addition, the 6-week old CBS-KO rabbits showed higher plasma levels of Hcy, triglycerides (TG), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) compared to the age-matched wild-type (WT) controls. Histological analysis of the mutants showed accumulation of micro-vesicular cytoplasmic lipid droplets in the hepatocytes. However, gastric infusion of vitamin B and betaine complex significantly decreased the plasma levels of TG, TC and LDL-C in the CBS-KO rabbits, and alleviated hepatic steatosis compared to the untreated animals.

Conclusion

A CBS^G307S rabbit model was generated that exhibited severe dyslipidemia when fed on a normal diet, indicating that G307S mutation in the CBS gene is a causative factor for dyslipidemia.

Characteristics of the carotid plaque in hypertensive patients with hyperhomocysteinemia using multimode ultrasound

BACKGROUND

Ischemic stroke is related to the level of total homocysteine and the stability of carotid atherosclerotic plaque. In this study, the characteristics of carotid plaque in hypertensive patients with hyperhomocysteinemia were preliminarily studied by conventional ultrasound, contrast-enhanced ultrasound and virtual touch image quantification.

METHODS

Hypertensive patients (n=196) hospitalised in the Department of Neurology and Cardiology of our hospital from April 2016 to February 2019 were studied to compare and analyse differences in general clinical data, conventional ultrasound, contrast-enhanced ultrasound and virtual touch image quantification between hypertension with hyperhomocysteinemia and hypertension with normal tHcy.

RESULTS

1. There was no statistical difference in other clinical data, except fasting blood sugar (P=0.021) and the history of cerebral infarction (P=0.0001). 2. There were significant differences in plaque thickness, stenosis degree, contrast-enhanced ultrasound level, The maximum shear wave velocity (SWVmax) , the minimum shear wave velocity (SWVmin) and the mean shear wave velocity (SWVmean) (P<0.05), except intima-media thickness between the two groups (t=0.160, P=0.873). 3. Blood tHcy level in hypertensive patients with hyperhomocysteinemia was positively correlated with carotid plaque thickness, stenosis degree and contrast-enhanced ultrasound level (r=0.349, 0.647, 0.421), but negatively correlated with SWVmax, SWVmin and SWVmean (r=-0.348, -0.409, -0.393).

CONCLUSIONS

Ultrasonography can reflect the vulnerability of hypertensive patients with hyperhomocysteinemia, providing reliable and comprehensive information for the prevention and treatment of stroke in hypertensive patients with hyperhomocysteinemia.

Modifiable risk factors for carotid atherosclerosis: a meta-analysis and systematic review

Background

Carotid atherosclerosis is a major cause of stroke, but the conclusion about risk factors for carotid atherosclerosis is still controversial. The aim of our present meta-analysis and systematic review was to explore the modifiable risk factors for carotid atherosclerosis.

Methods

We searched PubMed from January 1962 to October 2018 to include longitudinal and cross-sectional studies. The results were pooled using random effects model. Heterogeneity was measured by I² statistic and publication bias was assessed by funnel plots.

Results

A total of 14,700 articles were screened, of which 76 with 27 factors were eligible. Our meta-analysis of cross-sectional studies indicated nine factors (hyperlipidemia, hyperhomocysteinemia, hypertension, hyperuricemia, smoking, metabolic syndrome, hypertriglyceridemia, diabetes, and higher low density lipoprotein) were significantly associated with the presence of carotid plaque, among which four (hyperlipidemia, hyperhomocysteinemia, hypertension, and hyperuricemia) could elevate the risk of atherosclerosis by at least 50%; and one factor (hypertension) was associated with increased carotid intima-media thickness. In the systematic review, another five factors [negative emotion, socioeconomic strain, alcohol, air pollution, and obstructive sleep apnea syndrome (OSAS)] were also related to the presence of atherosclerosis. The cross-sectional associations with most of the above 14 factors were further confirmed by longitudinal studies. Among them, the managements of 4 factors (hypertension, hyperlipidemia, diabetes and OSAS) were indicated to prevent carotid atherosclerosis by cohort studies.

Conclusions

Effective interventions targeting pre-existing disease, negative emotion, lifestyle and diet may reduce the risk of carotid atherosclerosis. Further good-quality prospective studies are needed to confirm these findings.

Association between homocysteine and multivascular atherosclerosis in stroke-related vascular beds determined by three-dimensional magnetic resonance vessel wall imaging

BACKGROUND

Atherosclerosis in stroke-related vascular beds is the major cause of stroke. Studies demonstrated that multivascular atherosclerosis is prevalent in stroke patients and those with multivascular plaques had higher risk of recurrent stroke.

OBJECTIVES

This study investigated the relationship between homocysteine and multivascular atherosclerosis in stroke-related vascular beds using magnetic resonance imaging.

METHODS

Patients with recent ischemic cerebrovascular symptoms were enrolled and underwent three-dimensional magnetic resonance vessel wall imaging for intracranial arteries, extracranial carotid arteries and aortic arch. Traditional risk factors and homocysteine were measured. Presence of multivascular plaques defined as plaques in at least two stroke-related vascular beds on magnetic resonance imaging was determined. The relationship between homocysteine and characteristics of multivascular plaques was determined.

RESULTS

Of 49 enrolled patients (mean age: 56.3 ± 13.8 years; 35 males), 23 had multivascular plaques. Homocysteine (odds ratio, 1.17; 95% confidence interval, 1.02-1.34; p = 0.022) and age (odds ratio, 1.71; 95% confidence interval, 1.22-2.41; p = 0.002) were significantly associated with presence of multivascular plaques. The adjusted associations remained significant (both p < 0.05). In discriminating presence of multivascular plaques, the area-under-the-curve of age, homocysteine and combination of them was 0.79, 0.70 and 0.87 respectively.

CONCLUSIONS

Homocysteine is independently associated with stroke-related multivascular plaques and combination of age and homocysteine has stronger predictive value.

Association between non-high-density lipoprotein cholesterol levels and asymptomatic vulnerable carotid atherosclerotic plaques

BACKGROUND AND PURPOSE

Carotid atherosclerosis, especially rupture of plaques, is related to cerebrovascular diseases. Non-high-density lipoprotein cholesterol (non-HDL-C) is relevant to cerebrovascular diseases and may be a potential risk factor. We designed this study to investigate the association between non-HDL-C and the prevalence of asymptomatic vulnerable carotid atherosclerotic plaques.

METHODS

We enrolled 2888 participants who underwent carotid atherosclerotic plaque detection and non-HDL-C measurement, with no history of taking lipid-lowering agents, from the Asymptomatic Polyvascular Abnormalities in Community study. We used multivariable logistic regression to estimate the association between non-HDL-C levels and the presence of asymptomatic vulnerable carotid atherosclerotic plaques.

RESULTS

In our study, 1505 subjects had asymptomatic vulnerable carotid atherosclerotic plaques and 1383 subjects had stable plaques. After adjustment for confounding factors, the odds ratios for vulnerable plaques of non-HDL-C levels in the middle and highest tertile groups were 1.02 (95% confidence interval, 0.84-1.23) and 1.50 (95% confidence interval, 1.23-1.82), respectively (P trend < 0.01).

CONCLUSION

In our community-based observational and cross-sectional study, non-HDL-C level was a significant risk factor for the occurrence of asymptomatic vulnerable carotid plaques.

Plasma homocysteine levels and intracranial plaque characteristics: association and clinical relevance in ischemic stroke

Background

Elevated plasma homocysteine (Hcy) is an independent risk factor for ischemic stroke. This study aimed to evaluate the association between Hcy levels and intracranial plaque characteristics and to investigate their clinical relevance in ischemic stroke.

Methods

Ninety-four patients with intracranial atherosclerosis (ICAS) were enrolled. Plasma Hcy levels were measured. Intracranial plaque characteristics including plaque enhancement, stenosis ratio, T2 and T1 hyperintense components were assessed on high-resolution magnetic resonance imaging. Logistic regression model was constructed to analyze the association between high Hcy levels and plaque characteristics, and their synergistic effects to predict the likelihood for ischemic stroke, while adjusting for demographics and traditional atherosclerotic risk factors.

Results

Elevated Hcy level was associated with strong plaque enhancement independently of age, sex, serum creatinine levels and other atherosclerotic risk factors ((P < 0.001, OR 6.00, 95% confidence interval [CI] 2.28–15.74). Both strong plaque enhancement (P = 0.026, OR 5.63, 95% CI 1.23–25.81) and high Hcy level (P = 0.018, OR 6.20, 95% CI 1.36–28.26) were correlated with acute ischemic stroke. The combination of them strengthened the ability to stratify the likelihood for ischemic stroke, with an improved area under the receiver operating characteristic curve (AUC) of 0.871, significantly higher than that of strong plaque enhancement (0.755) and high Hcy level (0.715) alone (P < 0.05 for both).

Conclusions

High Hcy level appears to have association with intracranial strong plaque enhancement. The combined assessment of plasma Hcy levels and plaque enhancement may improve ischemic stroke risk stratification.

Homocysteine accelerates atherosclerosis via inhibiting LXRα-mediated ABCA1/ABCG1-dependent cholesterol efflux from macrophages

AIMS

Macrophage-derived foam-cell formation plays a crucial role in the development of atherosclerosis, and liver X receptor alpha (LXRα) is a key regulator of lipid metabolism in macrophages. Homocysteine (Hcy) is an independent risk factor of atherosclerosis; however, the regulation of lipid metabolism and role of LXRα induced by Hcy in macrophages is still unknown. The present study aimed to investigate the potential role of Hcy in disordered lipid metabolism and atherosclerotic lesions, especially the effects of Hcy on cholesterol efflux in macrophages and the possible mechanisms.

MAIN METHODS

In vitro, lipid accumulation and cholesterol efflux were evaluated in THP-1 macrophages with Hcy intervention. Real-time quantitative PCR and western blot analyses were used to assess mRNA and protein levels. In vivo, atherosclerotic lesions and lipid profiles were evaluated by methionine diet-induced hyperhomocysteinemia (HHcy) in ApoE^-/- mice. The LXRα agonist T0901317 was used to verify the role of LXRα in HHcy-accelerated atherosclerosis.

KEY FINDINGS

Hcy promoted lipid accumulation and inhibited cholesterol efflux in THP-1 macrophages. HHcy mice showed increased lesion area and lipid accumulation in plaque. Both studies in vitro and in vivo showed decreased expression of ATP binding cassette transporter A1 (ABCA1) and G1 (ABCG1). T0901317 treatment increased ABCA1 and ABCG1 levels; reversed macrophage-derived foam-cell formation in THP-1 macrophages and reduced atherosclerotic lesions in ApoE^-/- mice.

SIGNIFICANCE

Inhibition of LXRα-mediated ABCA1/ABCG1-dependent cholesterol efflux from macrophages is a novel mechanism in Hcy-accelerated atherosclerosis.

Changes in total homocysteine levels after acute stroke and recurrence of stroke

It is not known how total homocysteine (tHcy) levels change during the transition from acute stroke to post-stroke convalescence or whether tHcy changes occurring after the acute period are associated with recurrence of cerebro-cardiovascular events. Levels of tHcy were measured during acute ischemia and again after three months. Patients were followed for a median of 18 (range: 12–36) months. A total of 2800 patients who had at least two tHcy measurements were enrolled between February 2012 and June 2014; 2587 patients presented with ischemic stroke and 213 presented with cerebral hemorrhage. During the follow-up period, 220 (7.9%) patients experienced another ischemic event. After adjusting for additional cardiovascular risk factors, patients with the highest levels of tHcy (fourth quartile; >15.5 μmol/L) had a 1.76-fold increased risk of a recurrence (adjusted HR: 1.76, 95%CI: 1.11–3.08) as compared to patients with the lowest levels of tHcy (lowest quartile; ≤9.65 μmol/L). Additional analysis by subgroup indicated that this correlation was only significant for patients with large-artery atherosclerosis ischemia (adjusted HR: 2.00, 95%CI: 1.13–3.55). Elevated tHcy during the convalescent phase of acute stroke was independently associated with an increased risk of recurrent ischemic stroke, especially in those patients with large-vessel atherosclerosis ischemia.

Carotid Plaque Stiffness Measured with Supersonic Shear Imaging and Its Correlation with Serum Homocysteine Level in Ischemic Stroke Patients

Objective

To ascertain the feasibility of using shear wave velocity (SWV) in assessing the stiffness of carotid plaque by supersonic shear imaging (SSI) and explore preliminary clinical value for such evaluation.

Materials and Methods

Supersonic shear imaging was performed in 142 patients with ischemic stroke, including 76 males and 66 females with mean age of 66 years (range, 45-80 years). The maximum, minimum, and mean values of SWV were measured for 129 carotid plaques. SWVs were compared between echolucent and echogenic plaques. Correlations between SWVs and serum homocysteine levels were investigated. Based on neurological symptom, the surrogate marker of vulnerable plaque (VP), binary logistic regression was performed and area under curve (AUC) of homocysteine only and homocysteine combing SWV_mean was calculated respectively.

Results

Echogenic plaques (n = 51) had higher SWVs than echolucent ones (n = 78) (SWV_min 3.91 [3.24-4.17] m/s vs. 1.51 [1.04-1.94] m/s; SWV_mean, 4.29 [3.98-4.57] m/s vs. 2.09 [1.69-2.41] m/s; SWV_max, 4.67 [4.33-4.86] m/s vs. 2.62 [2.32-3.31] m/s all p values < 0.01). Pearson correlation analysis showed that stiffness of plaques was negatively correlated with homocysteine level. R values for SWV_min, SWV_mean, and SWV_max were -0.205, -0.213, and -0.199, respectively. Binary logistic regression analysis showed that sex (p = 0.008), low-density lipoprotein (p = 0.015), triglycerides (p = 0.011), SWV_mean (p = 0.004), and hyper-homocysteinemia (p = 0.010) were significantly associated with symptomatic ischemic stroke. Receiver operating characteristic curves revealed that SWV_mean combing serum homocysteine level (AUC = 0.67) presented better diagnostic value than serum homocysteine only (AUC = 0.60) for symptomatic ischemic stroke.

Conclusion

Supersonic shear imaging could be used to quantitatively evaluate stiffness of both echolucent and echogenic carotid plaques. More importantly, SWVs of plaques were not only correlated to serum homocysteine level, but also associated with symptomatic ischemic stroke, suggesting that SSI might be useful for understanding more about VP.

Methylenetetrahydrofolate reductase gene A1298C polymorphism and gene-environment interactions are associated with carotid plaque in a south Chinese population

OBJECTIVE

Our primary objective was to evaluate the associations of conventional risk factors and methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms with the risk of carotid plaque in a south Chinese population. Our secondary objective was to explore gene-environment interactions and potential relationship with carotid plaque.

METHOD

We enrolled 229 patients suffer from carotid plaque and 180 controls in this case-control study. We measured the carotid intima-media thickness by ultrasound and investigated conventional risk factors, biomarkers and C677T/A1298C MTHFR genotypes. Logistic analysis was used to evaluate the association between conventional risk factors and carotid plaque. The SNPstats platform was used to investigate the association between MTHFR gene polymorphisms and carotid plaque under 5 genetic models (dominant, recessive, codominant, over dominant and additive models). Gene-environment interactions analysis was then performed by multifactor dimensionality reduction.

RESULTS

Age and hypertension were identified as independent risk factors of carotid plaque. C677T and A1298C demonstrated associations with carotid plaque under the recessive model (C677T: P = 0.03, odds ratio = 3.14, 95% confidence interval = 1.04-11.21; A1298C: P = 0.018, odds ratio = 2.40, 95% confidence interval = 1.13-5.10). Neither C677T nor A1298C polymorphism was associated with stable or vulnerable plaques. Additionally, Significant multiplicative and additive interactions were observed in terms of carotid plaque between A1298C polymorphism and diabetes, age, and smoking (P = 0.013).

CONCLUSION

MTHFR gene C677T and A1298C polymorphisms may act as modifiers of carotid plaque risk in south Chinese population. In addition, the combined effect of gene-environment interactions between A1298C polymorphism and conventional risk factors may promote the progression of carotid plaque.

Involvement of histone methylation in macrophage apoptosis and unstable plaque formation in methionine-induced hyperhomocysteinemic ApoE-/- mice

AIMS

Hyperhomocysteinemia (Hhcy) is an independent risk factor of atherosclerosis and promotes unstable plaque formation. Epigenetic mechanisms play an important role in the pathogenesis of atherosclerosis induced by Hhcy. However, the exact mechanism is still undefined. Lesional apoptotic cells and necrotic core formation contribute greatly to the progression of plaque. The present study sought to determine whether modification of histone methylation is involved in macrophage apoptosis and unstable plaque formation in the condition of Hhcy.

MATERIALS AND METHODS

The unstable plaque formation, lesional apoptotic cells and status of histone methylation were monitored in the aortas of Hhcy ApoE-/- mice induced by a high-methionine (HM) diet for 20weeks. Involvement of histone methylation in macrophage apoptosis and foam cell formation were assessed in macrophage Raw 264.7 cells after being challenged with homocysteine alone or in combination with the histone methylation inhibitor BIX 01294.

KEY FINDINGS

The unstable plaque formation and lesion apoptotic cells are increased in ApoE-/- mice supplemented with high-methionine (HM), accompanied with a decreased expression of histone H3 lysine 9 dimethylation. Hhcy increases the apoptosis of macrophages and inhibits the histone H3 lysine 9 dimethylation, as well as the expression of histone methyltransferase G9a in vitro. Inhibition of histone methylation by BIX01294 enhances macrophage apoptosis and foam cell formation in vitro.

SIGNIFICANCE

Our data suggest that Hhcy promotes the progression of atherosclerosis via macrophage apoptosis. Histone methylation might be involved in macrophage apoptosis and unstable plaque formation in methionine induced hyperhomocysteinemic ApoE-/- mice.

Sex Differences in Prevalence of and Risk Factors for Carotid Plaque among Adults: A Population-based Cross-Sectional Study in Rural China

Although the associations between carotid plaque and cardiovascular disease risk factors have been identified in previous studies, there is limited information on sex-related differences in factors associated with the development of carotid plaque. We aimed to determine sex differences in the prevalence of carotid plaque and associated risk factors in rural China. A total of 3,789 subjects aged ≥45 years without history of stroke or cardiovascular disease were recruited to the study. B-mode ultrasonography was performed to determine the presence of carotid plaque. The mean age of male subjects was greater than that of female subjects. In addition, there was a higher prevalence of carotid plaque in men than in women (50.1% vs. 35.5%; P < 0.001) irrespective of age group, education level, and presence of risk factors. Older age, hypertension, diabetes mellitus, and high concentrations of low-density lipoprotein cholesterol were pronouncedly associated with the risk of carotid plaque in both men and women. These findings suggest that it is vital for physicians to be aware that conventional risk factors and other related factors are of equal importance among rural residents in China; patients should thus be treated accordingly so that reduce the burden of stroke and cardiovascular disease.

Homocysteine and Its Relationship to Asymptomatic Carotid Stenosis in a Chinese Community Population

Little is known about the association between homocysteine (Hcy) and asymptomatic CAS in the healthy population. The purpose of this study was to investigate the relationship between Hcy levels and asymptomatic CAS in a Chinese community population. The current study included 5393 participants who were age of 40 years or older, and free of stroke, transient ischemic attack, and coronary artery disease. Demographic and clinical variables were investigated, and the presence of CAS was assessed by Color Doppler Ultrasound. A multivariate logistic regression was used to examine the association between Hcy levels and asymptomatic CAS. 361 (6.69%) participants were diagnosed with asymptomatic CAS, who had higher Hcy levels compared with those without (p-value for trend = 0.0001). After adjusting other possible risk factors, Hcy > 19.3μmol/L was considered as an independent indicator of asymptomatic CAS (OR 1.53, 95%CI 1.05–2.23; p-value for trend = 0.0265), but with a difference between participants with diabetes and without [OR (95%CI): 2.89(1.02–8.22) vs. 1.42(0.95–2.12); P interaction < 0.05]. In this large-population, community-based study, Hcy is an independent indicator of asymptomatic CAS, especially in patients with diabetes.

The Association between Serum Uric Acid Levels and the Prevalence of Vulnerable Atherosclerotic Carotid Plaque: A Cross-sectional Study

Little is known about the associations between serum uric acid (SUA) levels and atherosclerotic carotid plaque vulnerability. The aim of this study was to assess the associations of SUA levels with the prevalence of vulnerable atherosclerotic carotid plaque in a community-based cohort. In the Asymptomatic Polyvascular Abnormalities Community (APAC) study, cross-sectional data from 2860 Chinese residents who underwent SUA measurement and ultrasonographic assessment of carotid plaque were analyzed. Multivariable logistic regression models were used to assess the associations of SUA levels with presence of vulnerable carotid plaque. After adjustment for potential confounders, SUA levels were significantly associated with the prevalence of vulnerable plaque amongst the middle-aged adults (odds ratio [OR] = 1.19, 95% confidence interval [CI]: 1.11-1.28). Compared to the lowest quartile, quartiles 2, 3 and 4 had a prevalence OR of 1.33 (1.02-1.74), 1.70 (1.27-2.27) and 2.05 (1.53-2.75), respectively, for the presence of vulnerable carotid plaque (p for trend across quartiles < 0.001). In the APAC study, elevated SUA levels were independently associated with the prevalence of vulnerable carotid plaque in middle-aged adults.