The Potential of Single Nucleotide Polymorphisms (SNPs) as Biomarkers and Their Association with the Increased Risk of Coronary Heart Disease: A Systematic Review

Human genetic analyses and epidemiological studies showed a potential association between several types of gene polymorphism and the development of coronary heart disease (CHD). Many studies on this pertinent topic need to be investigated further to reach an evidence-based conclusion. Therefore, in this current review, we describe several types of gene polymorphisms that are potentially linked to CHD. A systematic review using the databases EBSCO, PubMed, and ScienceDirect databases was searched until October of 2022 to find relevant studies on the topic of gene polymorphisms on risk factors for CHD, especially for the factors associated with single nucleotide polymorphisms (SNPs). The risk of bias and quality assessment was evaluated by Joanna Briggs Institute (JBI) guidelines. From keyword search results, a total of 6243 articles were identified, which were subsequently narrowed to 14 articles using prespecified inclusion criteria. The results suggested that there were 33 single nucleotide polymorphisms (SNPs) that can potentially increase the risk factors and clinical symptoms of CHD. This study also indicated that gene polymorphisms had a potential role in increasing CHD risk factors that were causally associated with atherosclerosis, increased homocysteine, immune/inflammatory response, Low-Density Lipoprotein (LDL), arterial lesions, and reduction of therapeutic effectiveness. In conclusion, the findings of this study indicate that SNPs may increase risk factors for CHD and SNPs show different effects between individuals. This demonstrates that knowledge of SNPs on CHD risk factors can be used to develop biomarkers for diagnostics and therapeutic response prediction to decide successful therapy and become the basis for defining personalized medicine in future.

Optimisation of individual cardiovascular risk assessment in a German coronary artery disease cohort using a commercial test for genetic polymorphisms - a pilot study

BACKGROUND AND AIMS

Assessment of cardiovascular risk using established risk scores such as ESC SCORE2 or PROCAM insufficiently emphasise the role of genetic factors. We hypothesise that commercially available genetic assays may provide additional information on hereditary cardiovascular risk in a timely and cost-efficient manner.

METHODS

In a cohort of 51 patients treated for coronary artery disease (CAD) at University Hospital Heidelberg, Germany, a subgroup of patients with "unstable" CAD (i.e. recurrent acute coronary syndrome) was identified and compared to patients with "stable" disease (i.e. chronic coronary syndrome). Gene array analysis using a commercial assay for 15 potentially pathogenic polymorphisms revealed our cohort's genetic risk profile regarding atherosclerotic/thromboembolic events. Improvement of cardiovascular risk assessment based on established risk scores was analysed using net reclassification, logistic regression and receiver operating characteristic (ROC) analysis.

RESULTS

Discriminatory capacity of traditional risk scores such as SCORE2 or PROCAM with regard to stable and unstable CAD groups was poor (ROC AUC <0.5). Patients with "unstable" CAD exhibited a significantly increased frequency of pathogenic eNOS 894 T and MTHFR 1298 C polymorphisms compared to "stable" CAD patients, and information on these polymorphisms individually as well as combinations with additional polymorphisms included in the assay such as ACE D/D or PAI-1 5 G variants markedly improved risk prediction compared to SCORE2/PROCAM alone (ROC AUC ≥0.75).

CONCLUSION

Commercially available assays for genetic polymorphisms may provide valuable information on individual genetic cardiovascular risk, potentially guiding future primary and/or secondary preventative therapies for coronary artery disease.

Sortilin and Homocysteine as Potential Biomarkers for Coronary Artery Diseases

Purpose

The aim of this study was to assess the relationship of coronary artery disease (CAD) with levels of homocysteine and sortilin in Egyptian patients.

Background

CAD is a primary contributor to cardiac disease and a prominent cause of death globally.

Patients and Methods

We enrolled 45 patients with CAD evaluated by coronary CT angiography and 42 control subjects without CAD. Plasma-homocysteine and -sortilin levels were measured with a commercial ELISA kit.

Results

Elevated levels of homocysteine and sortilin were observed in the CAD patients compared to controls (13.75±1.40 vs 7.73±2.06 μmol/L, P=0 and 160.91±32.17 vs 143.02±32.30 ng/dL, P=0.02, respectively). Significantly higher total cholesterol, low density–lipoprotein cholesterol and triglycerides (P<0.05) and lower high density–lipoprotein cholesterol (P<0.05) were seen among patients with CAD than the control group. Sortilin levels were positively associated with homocysteine levels (r=0.32, P=0.006), total cholesterol (r=0.61, P=0), low density–lipoprotein cholesterol (r=0.37, P=0.001), triglycerides (r=0.91, P=0), troponin I (r=0.82, P=0), Gensini score (r=0.93, P=0) and high-sensitivity CRP (r=0.87, P=0) in all subjects. Homocysteine has a significantly negative association with high density–lipoprotein cholesterol (r=−0.42, P=0).

Conclusion

Elevated homocysteine and sortilin levels are crucial risk factors of CAD in Egyptian patients.

The Connotation of Variances in the Risk Predictors, Medications, Homocysteine, and Homocysteine Pathway Gene Polymorphisms with CVA/Stroke

Cerebrovascular accidents (CVAs) are vascular multifactorial, multigenic ailments with intricate genetic, environmental risk influences. The present study aimed to establish affiliation of CVAs/stroke with blood parameters, differences in prescribed drugs consumption, and with differences in homocysteine pathway genes polymorphisms. The participants in study included controls n  = 251, transient ischemic attack (TIA) patients n  = 16, and stroke cases n  = 122, respectively, (total participants, n  = 389). The analyzed single nucleotide polymorphisms (SNPs) included C677T(rs1801133), A1298C(rs1801131) of methylene tetrahydrofolate reductase ( MTHFR ), A2756G(rs1805087) of methyl tetrahydrofolate homocysteine methyltransferase/methionine synthase ( MS ), and the A192G(rs662) of paraoxonase 1( PON1 ) genes, all validated by tetra-primer allele refractory mutation system polymerase chain reaction (T-ARMS-PCR). The insertion deletion (I/D; rs4646994) polymorphism in angiotensin converting enzyme ( ACE ) gene was analyzed using routine PCR. All studied traits were scrutinized through analysis of variance (ANOVA), and later through regression analysis. Through ANOVA and multiple comparison, there was association of CVA with serum homocysteine, cholesterol, and with diastolic blood pressure readings. When data was subjected to regression, serum homocysteine and diastolic blood pressure (significant through ANOVA), as well as two additional traits, high-density lipoproteins (HDL), and rs1801133 MTHFR SNP sustained statistical significance and noteworthy odds in relation to CVA and stroke. The ailments affecting cerebral vasculature are mutifactorial, whereby genes, proteins, and environmental cues all exert cumulative effects enhancing CVA risk. The current study emphasizes that SNPs and variation in circulating biomarkers can be used for screening purposes and for reviewing their effects in stroke/CVA-linked risk progression.

Association of myeloperoxidase, homocysteine and high-sensitivity C-reactive protein with the severity of coronary artery disease and their diagnostic and prognostic value

In the present study, the association between the severity of coronary artery disease (CAD) and myeloperoxidase (MPO), homocysteine (Hcy) and high-sensitivity C-reactive protein (hs-CRP) was assessed and their diagnostic and prognostic value was determined. A total of 112 patients with CAD [patient group (PG)] and 112 healthy participants who visited the hospital for physical examinations [control group (CG)] were enrolled in the present study. The plasma levels of MPO, Hcy and hs-CRP were compared between the two groups. According to the arteriography results, the patients were further divided into the single-vessel disease group (SVG), double-vessel disease group (DVG) and multi-vessel disease group (MVG). The Gensini scores of the three groups were evaluated according to the Gensini score standard. The correlations between the expression of MPO, Hcy or hs-CRP and the Gensini score of the PG were analyzed. The patients' major adverse cardiovascular event (MACEs) were recorded over 6 months and compared, and the predictive values of MPO, Hcy and hs-CRP regarding MACEs were determined by receiver operating characteristics analysis. The results indicated that the levels of MPO, Hcy and hs-CRP in the PG were higher than those in the CG (P<0.05). The Gensini score and the expression of MPO, Hcy and hs-CRP in the MVG were higher than those in the SVG and the DVG, and the Gensini score and the expression of MPO, Hcy and hs-CRP in the DVG were higher than those in the SVG (P<0.05). There was a positive correlation between the Gensini score and the expression of MPO (r=0.814, P<0.05), Hcy (r=0.774, P<0.05) and hs-CRP (r=0.765, P<0.05) in the PG. The total incidence of MACEs in patients with multiple lesions was significantly higher than that in patients with double and single lesions (P<0.05). The total incidence of MACEs in the MVG group was higher than that in the SVG and the DVG, and the total incidence of MACEs in the DVG was higher than that in the SVG (P<0.05). The area under the curve (AUC) and sensitivity for MPO levels to predict MACEs were higher than those of Hcy and hs-CRP (P<0.05); however, there was no significant difference in the AUC and sensitivity of Hcy and hs-CRP for predicting MACEs (P<0.05). The specificity of hs-CRP for predicting MACEs was higher than that of MPO and Hcy (P<0.05). The number of lesions, hypertension, diabetes, MPO, Hys and hs-CRP were determined to be independent risk factors for MACEs. In conclusion, for patients with CAD, elevated plasma levels of MPO, Hcy and hs-CRP were directly correlated with the severity of CAD and the risk of MACEs. Furthermore, MPO, Hcy and hs-CRP may effectively predict MACEs and are of important clinical significance in terms of judging the condition and improving the prognosis for patients with CAD.

CBS promoter hypermethylation increases the risk of hypertension and stroke

OBJECTIVES

Cystathionine β-synthase is a major enzyme in the metabolism of plasma homocysteine. Hyperhomocysteinemia is positively associated with hypertension and stroke. The present study was performed to examine the possible effects of Cystathionine β-synthase promoter methylation on the development of hypertension and stroke.

METHODS

Using quantitative methylation-specific PCR, we determined the Cystathionine β-synthase methylation levels in 218 healthy individuals and 132 and 243 age- and gender-matched stroke and hypertensive patients, respectively. The relative changes in Cystathionine β-synthase promoter methylation were analyzed using the 2-ΔΔCt method. The percent of the methylated reference of Cystathionine β-synthase was used to represent the Cystathionine β-synthase promoter methylation levels.

RESULTS

In this study, the Cystathionine β-synthase promoter methylation levels of hypertensive and stroke participants were both higher than that of the healthy individuals (median percentages of the methylated reference were 50.61%, 38.05% and 30.53%, respectively, all p<0.001). Multivariable analysis showed that Cystathionine β-synthase promoter hypermethylation increased the risk of hypertension [odds ratio, OR (95% confidence interval, CI)=1.035 (1.025-1.045)] and stroke [OR (95% CI)=1.015 (1.003-1.028)]. The area under the curve of Cystathionine β-synthase promoter methylation was 0.844 (95% CI: 0.796-0.892) in male patients with hypertension and 0.722 (95% CI: 0.653-0.799) in male patients with stroke.

CONCLUSION

Cystathionine β-synthase promoter hypermethylation increases the risk of hypertension and stroke, especially in male patients.

Betaine-rich sugar beet molasses protects from homocysteine-induced reduction of survival in Caenorhabditis elegans

PURPOSE

Homocysteine (Hcy) in humans represents a blood-borne biomarker which predicts the risk of age-related diseases and mortality. Using the nematode Caenorhabditis elegans, we tested whether feeding betaine-rich sugar beet molasses affects the survival under heat stress in the presence of Hcy, in spite of a gene loss in betaine-homocysteine methyltransferase.

METHODS

Knockdown of the genes relevant for remethylation or transsulfuration of Hcy was achieved by RNA interference (RNAi). Survival assay was conducted under heat stress at 37 °C and Hcy levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Addition of 500 mg/l betaine-rich sugar beet molasses (SBM) prevented the survival reduction that was caused by exposure to Hcy at 37 °C. Although SBM was no longer capable of reducing Hcy levels under RNAi versus homologues for 5, 10-methylenetetrahydrofolate reductase or cystathionine-β-synthase, it still enabled the survival extension by SBM under exposure to Hcy. In contrast, RNAi for the small heat shock protein hsp-16.2 or the foxo transcription factor daf-16 both prevented the extension of survival by betaine-rich molasses in the presence of Hcy.

CONCLUSIONS

Our studies demonstrate that betaine-rich SBM is able to prevent survival reduction caused by Hcy in C. elegans in dependence on hsp-16.2 and daf-16 but independent of the remethylation pathway.

Betaine reduces β-amyloid-induced paralysis through activation of cystathionine-β-synthase in an Alzheimer model of Caenorhabditis elegans

BACKGROUND

The neurodegenerative disorder Alzheimer's disease is caused by the accumulation of toxic aggregates of β-amyloid in the human brain. On the one hand, hyperhomocysteinemia has been shown to be a risk factor for cognitive decline in Alzheimer's disease. On the other hand, betaine has been demonstrated to attenuate Alzheimer-like pathological changes induced by homocysteine. It is reasonable to conclude that this is due to triggering the remethylation pathway mediated by betaine-homocysteine-methyltransferase. In the present study, we used the transgenic Caenorhabditis elegans strain CL2006, to test whether betaine is able to reduce β-amyloid-induced paralysis in C. elegans. This model expresses human β-amyloid 1-42 under control of a muscle-specific promoter that leads to progressive, age-dependent paralysis in the nematodes.

RESULTS

Betaine at a concentration of 100 μM was able to reduce homocysteine levels in the presence and absence of 1 mM homocysteine. Simultaneously, betaine both reduced normal paralysis rates in the absence of homocysteine and increased paralysis rates triggered by addition of homocysteine. Knockdown of cystathionine-β-synthase using RNA interference both increased homocysteine levels and paralysis. Additionally, it prevented the reducing effects of betaine on homocysteine levels and paralysis.

CONCLUSION

Our studies show that betaine is able to reduce homocysteine levels and β-amyloid-induced toxicity in a C. elegans model for Alzheimer's disease. This effect is independent of the remethylation pathway but requires the transsulfuration pathway mediated by cystathionine-β-synthase.

The future of nutrition: Nutrigenomics and nutrigenetics in obesity and cardiovascular diseases

Over time, the relationship between diet and health has aroused great interest, since nutrition can prevent and treat several diseases. It has been demonstrated that general recommendations on macronutrients and micronutrients do not affect to every individual in the same way because diet is an important environmental factor that interacts with genes. Thus, there is a growing necessity of improving a personalized nutrition to treat obesity and associated medical conditions, taking into account the interactions between diet, genes and health. Therefore, the knowledge of the interactions between the genome and nutrients at the molecular level, has led to the advent of nutritional genomics, which involves the sciences of nutrigenomics and nutrigenetics. In this review, we will comprehensively analyze the role of the most important genes associated with two interrelated chronic medical conditions, such as obesity and cardiovascular diseases.