Synergistic effect of sclerostin and angiotensin II receptor 1 polymorphism on arterial stiffening

Aim: We aimed to establish the association between sclerostin (a glycoprotein involved in bone metabolism) and development of pulse wave velocity (PWV) in the general population. Methods: A prospective cohort study with a total of 522 subjects. Aortic PWV was measured twice (at baseline and after approximately 8 years of follow-up) and intraindividual change in PWV per year (ΔPWV/year) was calculated. Results: ΔPWV/year increased across the sclerostin quintiles, but generally in a strong age-dependent manner. However, a significant independent positive association between sclerostin and ΔPWV/year was observed exclusively in C allele carriers of rs5186 polymorphism for the angiotensin II receptor 1 (n = 246). Conclusion: Sclerostin concentrations were associated with an accelerated natural course of arterial stiffening, but only in interaction with renin-angiotension system.

The low expression of circulating microRNA-19a represents an additional mortality risk in stable patients with vascular disease

BACKGROUND

Secondary prevention of atherosclerotic vascular diseases represents a cascade of procedures to reduce the risk of future fatal and non-fatal cardiovascular events. We sought to determine whether the expression of selected microRNAs influenced mortality of stable chronic cardiovascular patients.

METHODS

The plasma concentrations of five selected microRNAs (miR-1, miR-19, miR-126, miR-133 and miR-223) were quantified in 826 patients (mean age 65.2 years) with stable vascular disease (6-36 months after acute coronary syndrome, coronary revascularization or first-ever ischemic stroke). All-cause and cardiovascular mortality rates were followed during our prospective study.

RESULTS

Low expression (bottom quartile) of all five miRNAs was associated with a significant increase in five-year all-cause death, even when adjusted for conventional risk factors, treatment, raised troponin I and brain natriuretic protein levels [hazard risk ratios (HRRs) were as follows: miR-1, 1.65 (95% CI: 1.16-2.35); miR-19a, 2.27 (95% CI: 1.59-3.23); miR-126, 1.64 (95% CI: 1.15-2.33); miR-133a, 1.46 (95% CI: 1.01-2.12) and miR-223, 2.05 (95% CI: 1.45-2.91)]. Nearly similar results were found if using five-year cardiovascular mortality as the outcome. However, if entering all five miRNAs (along with other covariates) into a single regression model, only low miR-19a remained a significant mortality predictor; and only in patients with coronary artery disease [3.00 (95% CI: 1.77-5.08)], but not in post-stroke patients [1.63 (95% CI: 0.94-2.86)].

CONCLUSIONS

In stable chronic coronary artery disease patients, low miR-19a expression was associated with a substantial increase in mortality risk independently of other conventional cardiovascular risk factors.

Serum Vitamin D Status, Vitamin D Receptor Polymorphism, and Glucose Homeostasis in Healthy Subjects

Low vitamin D status has been frequently associated with impaired glucose metabolism. We examined associations between 25-hydroxyvitamin D (25-OH-D) and several parameters of glucose homeostasis in virtually healthy subjects, and explored possible interaction with vitamin D receptor (VDR) polymorphism. Nondiabetic subjects without chronic medication or any known significant manifest disease were selected from large general-population based population survey. Insulin sensitivity and β cell secretion were calculated by homeostasis model assessment (HOMA) and soluble isoform of receptor for advanced glycation end-products (sRAGE) using commercial ELISA. Subjects were also genotyped for rs2228570 polymorphism of VDR. After adjustment for potential confounders, we observed a significant relationship between 25-OH-D and fasting glycemia (β coefficient=-5.904; p=0.002) or insulin sensitivity (β=0.042; p=0.001), but not with β cell secretion or sRAGE. We found also an interaction with VDR polymorphism. Subjects with low 25-OH-D and AA genotype had significantly lower insulin sensitivity than those with GG genotype plus highest 25-OH-D concentrations (107.3% vs. 183.9%, p=0.021). In conclusion, low vitamin D status was in virtually healthy subjects associated with decreased insulin sensitivity, namely in those with GG genotype of rs2228570 VDR polymorphism.

Synergistic effect of low K and D vitamin status on arterial stiffness in a general population

Both vitamins K and D are nutrients with pleiotropic functions in human tissues. The metabolic role of these vitamins overlaps considerably in calcium homeostasis. We analyzed their potential synergetic effect on arterial stiffness. In a cross-sectional study, we analyzed aortic pulse wave velocity (aPWV) in 1023 subjects from the Czech post-MONICA study. Desphospho-uncarboxylated matrix γ-carboxyglutamate protein (dp-ucMGP), a biomarker of vitamin K status, was measured by sandwich ELISA and 25-hydroxyvitamin D3 (25-OH-D3) by a commercial immunochemical assay. In a subsample of 431 subjects without chronic disease or pharmacotherapy, we detected rs2228570 polymorphism for the vitamin D receptor. After adjustment for confounders, aPWV was independently associated with both factors: dp-ucMGP [β-coefficient(S.E.M.)=13.91(4.87); P=.004] and 25-OH-D3 [0.624(0.28); P=.027]. In a further analysis, we divided subjects according to dp-ucMGP and 25-OH-D3 quartiles, resulting in 16 subgroups. The highest aPWV had subjects in the top quartile of dp-ucMGP plus bottom quartile of 25-OH-D3 (i.e., in those with insufficient status of both vitamin K and vitamin D), while the lowest aPVW had subjects in the bottom quartile of dp-ucMGP plus top quartile of 25-OH-D3 [9.8 (SD2.6) versus 6.6 (SD1.6) m/s; P<.0001]. When we compared these extreme groups of vitamin K and D status, the adjusted odds ratio for aPWV≥9.3 m/s was 6.83 (95% CI:1.95-20.9). The aPWV was also significantly higher among subjects bearing the GG genotype of rs2228570, but only in those with a concomitantly poor vitamin K status. In conclusion, we confirmed substantial interaction of insufficient K and D vitamin status in terms of increased aortic stiffness.

The DRD2/ANKK1 Taq1A polymorphism is associated with smoking cessation failure in patients with coronary heart disease

AIM

We speculated whether DRD2 or CHRN subunit polymorphisms might be associated with the risk of smoking cessation failure in subjects after coronary heart disease (CHD) manifestation.

METHODS

A total of 964 patients with CHD, mean age 64.3 years (standard deviation [SD] 9.0), examined in the EUROASPIRE III and IV surveys were genotyped for rs1800497 (DRD2/ANKK1 Taq1A), rs578776 (CHRNA5-A3-B4), rs16969968 (CHRNA5) and rs1051730 (CHRNA3) SNPs.

RESULTS

The presence of DRD2/ANKK1 Taq1A minor T allele was independently associated with increased relative risk of smoking persistence (odds ratio: 1.79; 95% CI: 1.13-4.35). We observed no association between CHRN SNPs and smoking habit.

CONCLUSION

DRD2/ANKK1 Taq1A polymorphism is associated with a decreased likelihood of smoking cessation in patients after CHD manifestation.