Prognostic impact of adding Coronary Calcium Score to European SCORE2 in an asymptomatic Portuguese population

Introduction

The new European SCORE2 estimates the combined risk of fatal and non-fatal cardiovascular (CV) events, in contrast with SCORE's use for CV mortality only. Although controversial, several studies point out that Coronary Artery Calcification (CAC) scoring could improve CV risk stratification in primary prevention.

Purpose

Assess the impact of including CAC score to the new SCORE2 in MACE prediction and CV risk stratification in an asymptomatic Portuguese population.

Methods

The new SCORE2 was calculated in a population-based cohort of 1,014 individuals (mean age 58.6±8.5 years) without known CV disease and diabetes. Population was stratified into three SCORE2 risk categories (low-, moderate- and high-risk). According to the Hoff's nomogram, CAC score was categorized into: low CAC (0≤CAC<100 or P<50); moderate CAC (100≤CAC<400 or P50–75) and high or severe CAC (CAC≥400 or P>75). Kaplan-Meier survival curves were estimated and a multivariate regression analysis predicted the MACE risk for both scores. C-statistic methodology evaluated the ability of CAC when added to the SCORE2 model in MACE prediction.

Results

Kaplan-Meier curves showed that the highest categories of both scores presented a worst survival. Cox regression analysis showed that the highest categories of both CAC and SCORE2 remained in the equation with an increased MACE risk (HR) of 3.69 (p=0.008) and 9.87 (p=0.005), respectively, when compared with the lowest categories. C-statistic demonstrated that the predictive value for MACE increased from 0.668 (SCORE2 model) to 0.787 when CAC was included (p=0.012), showing a better predictive and discriminative capacity for MACE.

Conclusions

Our results highlight the importance of adding CAC score to SCORE2 in primary prevention to improve cardiovascular risk stratification and MACE risk prediction. Larger prospective multicenter cohorts with longer follow-up should reproduce and validate these findings.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): SESARAM EPERAM

Lipoprotein(a) and cardiovascular outcomes in patients with coronary artery disease and impaired glucose metabolism

Introduction

Lipoprotein(a) [Lp(a)] is an LDL-like molecule composed of a part of apolipoprotein(a) bounding covalently to apolipoprotein B-100. High plasma Lp(a) levels were associated with MACE in stable CAD patients. Recent research shows contradictory results in stable CAD patients with high Lp(a) plasmatic levels and impaired glucose metabolism in MACE occurrence.

Purpose

Investigate whether high Lp(a) levels were associated with MACE in CAD patients with impaired glucose metabolism, at an extended follow-up.

Methods

A prospective cohort of 1,127 CAD patients with impaired glucose metabolism (pre-diabetes and diabetes) was observed during 4.9±3.4 years. Pre-diabetes was considered when fasting plasma glucose ranged from 5.6 to 6.9 mmol/L, or hemoglobin A1c levels ranging from 5.7 to 6.4%. Lp(a) levels ≥30 mg/dL were considered high. Bivariate and multivariate Cox regression analysis evaluated the risk of Lp(a) ≥30 mg/dL for MACE occurrence. Kaplan-Meier curves estimated the survival probability for high and low Lp(a) levels.

Results

Of the patients with Lp(a) levels ≥30, 44.4% presented MACE and 32.0% had no MACE (p<0.0001). Cox regression analysis with smoking, hypertension, dyslipidemia, physical inactivity and kidney failure (creatinine clearance <60 mL/min) showed that high Lp(a) remained in the equation as an independent risk factor for MACE (HR=1.24; p=0.031). The Kaplan-Meier showed, at 10-year' follow-up, a better survival in the group with lower Lp(a) levels (p=0.023).

Conclusion

Our study demonstrated that high Lp(a) levels were an independent predictor of MACE and cardiovascular mortality in a CAD population with impaired glucose metabolism. Lp(a) measurement may help further risk stratification for diabetes and pre-diabetes patients suffering CAD. With the recent development of drugs that selectively lower Lp(a) levels, this marker can become a clinical target for reducing CVD risk.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): SESARAM EPERAM

Genetic information or coronary artery calcium score? What is more helpful in today's clinical practice?

Introduction

Coronary artery calcium (CAC) score has emerged as the most predictive cardiovascular risk marker in asymptomatic individuals, capable of adding prognostic information beyond the traditional risk factors (TRF). Genetic risk score (GRS) significantly improves cardiovascular genetic risk assessment at the individual level providing a more personalized measure of disease risk.

Purpose

We intend to evaluate which tool, added to TRF, is more valuable in predicting and discriminating cardiovascular events and death (MACE) - GRS or CAC score?

Methods

We performed a prospective study with 1153 participants without CAD history at baseline (74.2% male, age 51.7±8.3 years) during a mean follow-up of 5.4±3.4 years. We selected 14 SNPs previously associated with CAD presenting a risk (HR) for cardiovascular events ≥1. A weighted GRS was calculated, as the sum of these 14 risk alleles weighted by the corresponding effect size in prognostic (HR), and subsequently, subdivided into tertiles. CAC (Agatson) score was calculated in all participants and categorized into: low CAC (0≤CAC<100 or P<50); moderate CAC (100≤CAC<400 or P50–75) and high or severe CAC (CAC≥400 or P>75). Two models were created with TRF baseline (hypertension, smoking, body mass index, dyslipidemia, diabetes, chronic kidney disease, physical inactivity): 1) plus wGRS and 2) plus CAC score categories. Cox Regression Analyses and C-statistic assessed the predictive and discriminative capacity of both models.

Results

For model 1, Cox regression presented an HR of 4.292 for TRF (p=0.007) and 2.713 for 3rd tertile of wGRS (0.036). A modest but statistically significant improvement in MACE discriminative capacity was verified by adding wGRS to TRF, increasing the C-statistic from 0.617 to 0.687 (ΔC=0.070; p=0.013). On the other hand, model 2 better discriminated MACE when the CAC score (C-statistic = 0.765) was added to TRF (ΔC=0.148; p=0.001). Cox regression displayed an HR of 4.42 for TRF (p=0.015) and an HR of 4.55 for high-risk CAC score (p=0.001).

Conclusion

Our results suggest that adding a polygenic risk score to conventional risk factors provides a modest improvement in the discrimination of first-onset MACE. However, the CAC score added to the traditional model allows better discrimination of MACE compared to wGRS. CAC score could be helpful for MACE prediction, at least in individuals belonging to the higher genetic risk group. However, further investigation is required before clinical implementation.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): SESARAM EPERAM

Prognostic role of adding a genetic risk score to the new European SCORE2 in a cardiovascular events prediction, in a moderate-risk region

Introduction

The new SCORE2 provides risk estimates for the combined outcome of fatal and non-fatal cardiovascular disease (CVD) events, in contrast with SCORE's use for CVD mortality only. Genetic predisposition to CVD is not considered in SCORE2 for prevention and treatment.

Purpose

Evaluate the impact of adding a Genetic Risk Score (GRS) to the new European SCORE2 in MACE prediction and estimate the additional value in cardiovascular risk stratification in an asymptomatic Portuguese population.

Methods

A prospective study was performed in a population-based cohort of 1,100 individuals without known CVD and diabetes (mean age 53.3±6.9 years). For all included participants, SCORE2 was calculated and three risk categories were considered: low-, moderate- and high-risk. A 33-SNP GRS was constructed and two groups were analyzed: lower and higher than the GRS median. Kaplan-Meier survival curves were created and a Cox regression model was performed with the two scores to assess MACE risk. C-statistic methodology compared the model between SCORE2 solely and SCORE2 plus GRS.

Results

After Kaplan-Meier analysis for MACE occurrence, the high categories of SCORE 2 and GRS showed worst survival when compared to the lower categories (p<0.0001). Cox regression presented an HR of 8.528 (p=0.001) for high-risk SCORE2 and an HR of 4.520 (p<0.0001) for GRS higher than the median. C-statistic demonstrated that the SCORE2 predictive value was 0.678, increasing to 0.792 when GRS was included (p=0.0005).

Conclusions

In this work, combining SCORE2 with multiple genetic loci gathered into a GRS, improved the identification of patients with the worst prognosis. This new tool may be of great utility in risk stratification in primary prevention. Larger prospective multicenter cohorts with longer follow-up should reproduce and validate these findings.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): SESARAM EPERAM

Transcription factor 21 and prognosis in a coronary population

Introduction

TCF21 is a member of the basic helix-loop-helix (bHLH) transcriptor factor family, being critical for embryogenesis of the heart. It regulates epicardium-derived cells differentiation into smooth muscle (SMC) and fibroblast lineages. The biological roles of TCF21 in epicardial fate determination and the progression of atherosclerosis remains a controversial issue.

Purpose

Investigate the impact of the TCF21 rs12190287 G>C variant on the prognosis of a coronary artery disease (CAD) cohort.

Methods

A prospective study was performed with 1,713 CAD patients (mean age 53.3±7.8; 78.7% male) surveyed in terms of MACE occurrence in an extended follow-up of 5.0±4.3. TCF21 rs12190287 was genotyped and analysed using the dominant model (GC+CC) and, subsequently, compared with the wild-type GG to evaluate the survival probability by Kaplan-Meier. A Cox regression analysis with all the risk factors and genetic models was performed to assess the independent variables associated with the prognosis of CAD patients.

Results

GG wild genotype was present in 9.5% of the population, GC in 43.2% and the risk genotype CC accounted for 47.3% of the CAD patients. The dominant model GC+CC showed a worse survival throughout the follow-up period. After multivariate Cox regression analysis, this model remained in the equation as an independent risk factor for MACE occurrence with an HR of 1.41 (p=0.033) together with multivessel disease, physical inactivity, chronic kidney disease (CKD) and diabetes.

Conclusion

TCF21 rs12190287 is a risk factor for prognosis in our population. The role of this gene may influence fundamental SMC processes in response to vascular stress, accelerating atherosclerosis progression and may represent a target for future therapies.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): SESARAM EPERAM

ZNF259 rs964184 variant is associated with dyslipidemia and coronary artery disease in the young population

Introduction

Coronary artery disease (CAD) is a dynamic inflammatory disease caused by atherosclerosis. GWAS showed that ZNF259 rs964184 encoding zinc finger protein (ZPR1) was associated with dyslipidemia and CAD. Recent research found that ZPR1 transcription is up-regulated in the brain of mice fed a high-fat diet, influencing the cell cycle, apoptosis, and RNA metabolism in neurons. This process at the heart vessels may increase oxidative stress and CAD.

Purpose

Study the association between the ZNF259 rs964184 C>G polymorphism with dyslipidemia and CAD susceptibility in a Portuguese population.

Methods

A case-control study was performed with 3,160 individuals, namely 1,723 CAD patients (mean age 53.3±7.9; 78.7% male) and 1,437 controls (mean age 52.8±7.8; 76.3% male). Participants were stratified into two age groups (<45 and >55 years). ZNF259 rs964184 C>G was genotyped and analysed using the dominant model (CG+GG vs CC). Multivariate logistic regression was performed in both age groups to investigate whether rs964184 polymorphism was associated with dyslipidemia and CAD susceptibility.

Results

The dominant model of ZNF259 was associated with dyslipidemia (OR=1.85; 95% CI: 1.22–2.79; p=0.003) and CAD (OR=1.46; 95% CI: 1.02–2.09; p=0.036) in the younger population under 45 years. In the >55 years group, this model was associated with dyslipidemia (OR 1.46; 95% CI: 1.06–2.01; p=0.020) but not with CAD. After multivariate logistic regression, the CG+GG remained an independent risk factor for CAD susceptibility only in the population <45 years (OR=1.60; 95% CI: 1.03–2.50; p=0.037).

Conclusion

ZNF259 rs964184 is a risk factor for dyslipidemia in the whole population. Dyslipidemia may up-regulate ZPR1 transcription, enhancing the vulnerability of coronary endothelial cells to both oxidative stress and inflammatory response, increasing CAD susceptibility. This mechanism seems more relevant at the cellular level in young patients representing a possible prophylactic and therapeutic target, especially in this age group.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): SESARAM EPERAM

A Genetic Risk Score englobing variants associated with coronary artery disease is a good marker for prognosis in an asymptomatic population

 

Genome-wide association studies have identified several loci linked to coronary artery disease, and coronary atherosclerosis progression. However, the impact of the genetic contribution to MACE occurrence in sub-clinical atherosclerosis is unknown.

Purpose

This study intended to assess the relationship between a set of single nucleotide popymorphism (SNP) associated with CAD by GWAS and the MACE occurrence in an asymptomatic population. After that evaluate whether a wGRS englobing these variants is useful to estimate the prognostic.

Methods

Prospective study performed in an asymptomatic cohort from GENEMACOR population-based sample of 1114 subjects aged 51.7±8.3, 74.2 male, without prior coronary artery disease. Coronary Artery Calcium (CAC) score was assessed by coronary computed tomography (Agatston method), and two categories were considered 1–99 and >100. 33 SNP were evaluate to assess the significantly associated with prognostic. A weighted (wGRS) was constructed as the sum of the risk alleles weighted by the corresponding effect size (HR). Cox regression analysis adjusted for the main risk factors, calcium score (CAC) and wGRS to assess the risk of MACE during follow-up. Kaplan Meier assessed the survival.

Results

Of the studied 33 SNPs previously associated with CAD (GWAS), only 4 presented the significant association with MACE occurrence: CDKN2B-AS1 rs4977574, HNF4A rs1884613,

APOE rs7412/rs429358A and GJA4A rs 618675. After Cox regression analysis the wGRS remained in the equation (HR=2.834); p=0.012, together with CAC score (HR 3.35); p=0.012; diabetes (HR=2.398); p=0.032 and age (HR=1.056; p=0.049. WGRS above the median presented a worst survival rate (p=0.006).

Conclusion

The wGRS englobing: CDKN2B-AS1 rs4977574, HNF4A rs1884613, APOE rs7412/rs429358A and GJA4A rs 618675 is independently associated with cardiovascular events in an asymptomatic population. CDKN2B-AS1 rs4977574 gene expression modulates the progression and severity of vascular calcification in vascular smooth muscle cells (VSMCs), HNF1α-AS1 is an important regulatory molecule in cancer biology and cardiovascular disease (its expression may regulate VSMCs, and high expression promotes atheroprotection). More research is crucial for understand prognosis in asymptomatic population.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): SESARAM EPE

Anomalous x-ray diffraction peak broadening and lattice strains in Zn(1-x)Co(x)O dilute magnetic semiconductors

Nanocrystalline powders of Zn(1-x)Co(x)O synthesized by the coprecipitation technique show anomalous anisotropic broadening for x>0.05. This peak broadening is shown to be not only due to a reduction in the particle size but also due to a significant strain contribution, as confirmed by Williamson-Hall analysis. The presence of grouped Co(2+) ions, revealing the presence of clusters of high spin Co(2+) with antiferromagnetically coupled spins, as indicated by magnetization studies, seems to be responsible for the strain.

Pressure variation of reentrant transition temperature in liquid crystals

High pressure experimental studies show that in certain mesogenic materials, the nematic-smectic A (N-Sm A) transition temperature T(AN) exhibits nonlinear pressure dependence. As a consequence, the material shows reentrant phenomena that is a phase sequence nematic -- smectic A -- reentrant nematic appears. The characteristic features of this phenomenon have been addressed here within the framework of Landau-de-Gennes theory, where the coupling between nematic and smectic A order parameters (gamma, lambda(eff)) plays an important role. The cubic coupling gamma is chosen to be negative in order to form Sm A phase whereas the biquadratic coupling lambda(eff) is made large and positive to obtain reentrant behaviour. In the present work, we incorporate the pressure dependence in the theory through gamma and lambda(eff) which justifies the experimental pressure dependence in the reentrant transition temperature [Formula: see text]. The pressure dependence of gamma and lambda(eff) are employed in the calculation of excess specific heat capacity near the reentrant transition. The computed heat capacity shows strong pressure dependence near the reentrant transition which can be confirmed from high pressure measurement.

Influence of pressure on the electric-field-induced phase transitions in liquid crystals

Within the framework of Landau-de-Gennes formulation, we analyse the effect of pressure on electric-field-induced phase transitions in a liquid crystal which shows spontaneously an isotropic-smectic A transition. Inferring from the experimental pressure dependences on the layer spacing in smectic A phase, as well as the nematic-smectic A metastable temperature T*(AN), we incorporated the pressure dependence in the free energy through (the surface energy term) and the coupling between the quadrupolar nematic ordering Q(ij) and the smectic order parameter psi. From the S-T phase diagram, we found that the stability of field-induced nematic phase increases with pressure, whereas the discontinuity of the transition decreases. Also, the region where paranematic phase transits directly to smectic A phase increases with pressure.

Cdc53 is a scaffold protein for multiple Cdc34/Skp1/F-box proteincomplexes that regulate cell division and methionine biosynthesis in yeast

In budding yeast, ubiquitination of the cyclin-dependent kinase (Cdk) inhibitor Sic1 is catalyzed by the E2 ubiquitin conjugating enzyme Cdc34 in conjunction with an E3 ubiquitin ligase complex composed of Skp1, Cdc53 and the F-box protein, Cdc4 (the SCFCdc4 complex). Skp1 binds a motif called the F-box and in turn F-box proteins appear to recruit specific substrates for ubiquitination. We find that Skp1 interacts with Cdc53 in vivo, and that Skp1 bridges Cdc53 to three different F-box proteins, Cdc4, Met30, and Grr1. Cdc53 contains independent binding sites for Cdc34 and Skp1 suggesting it functions as a scaffold protein within an E2/E3 core complex. F-box proteins show remarkable functional specificity in vivo: Cdc4 is specific for degradation of Sic1, Grr1 is specific for degradation of the G1 cyclin Cln2, and Met30 is specific for repression of methionine biosynthesis genes. In contrast, the Cdc34-Cdc53-Skp1 E2/E3 core complex is required for all three functions. Combinatorial control of SCF complexes may provide a basis for the regulation of diverse cellular processes.

Regulation of the mating pheromone and invasive growth responses in yeast by two MAP kinase substrates

BACKGROUND

In the budding yeast Saccharomyces cerevisiae, components of a single mitogen-activated protein (MAP) kinase pathway transduce two distinct signals, each of which activates an independent developmental programme: peptide mating pheromones initiate the mating response, whereas nutrient limitation initiates filamentous growth. One of the MAP kinases in this pathway, Fus3, triggers mating but antagonizes filamentous growth, while the other, Kss 1, preferentially triggers filamentous growth. Both kinases activate the same transcription factor, Ste 12, which can stimulate gene expression specific to each of the developmental programmes. The precise mechanism by which these MAP kinases activate Ste 12, however, is not clear.

RESULTS

Two newly identified proteins, Rst 1 and Rst 2 (also known as Dig1 and Dig2), were found to associate physically with Fus3 and Ste12. Rst1 and Rst2 were prominent substrates in kinase reactions of Fus3 immune complexes from pheromone-treated cells. Association of Fus3 with Ste12 required Rst1 and Rst2, and activation of Fus3 by pheromone caused release of Ste12 from the Fus3 complex. Although rst1 and rst2 single mutants had no obvious phenotype, both filamentous growth and mating-specific gene expression were constitutive in rst1 rst2 double mutants. The phenotype of rst1 rst2 cells required Ste12 function, but did not require the function of upstream kinases. Consistent with Rst1 and Rst2 having a role in Ste12 regulation, both proteins were localized to the nucleus.

CONCLUSIONS

Rst1 and Rst2 repress the mating and filamentous growth responses of S. cerevisiae by directly inhibiting Ste12. Activation of Fus3 or Kss1 may cause phosphorylation-dependent release of Ste12 from Rst1/Rst2 and thereby activate Ste12-dependent transcription.