Parental history of myocardial infarction: lipid traits, gene polymorphisms and lifestyle

Age threshold for proper definition of premature coronary artery disease in males

BACKGROUND

There is no universally accepted definition for the cut point age before which atherosclerosis is considered "premature." This is a retrospective study aimed to utilize the medico legal autopsy information for finding a proper definition of the age threshold of premature atherosclerosis in males.

OBJECTIVES

This work aimed to utilize autopsy reports data that were issued at Jordan University Hospital to evaluate age-related differences in the distribution of coronary atherosclerotic and myocardial lesions and the determination of the age threshold at which such differences became apparent in male deaths. Such a threshold might provide a proper definition for premature atherosclerosis and premature sudden atherosclerotic cardiac death. At the same time, the meaning of a reference age for mature atherosclerotic death incidents could be elucidated.

METHODS

A total of 1139 male autopsy reports with sudden coronary atherosclerotic death were reviewed.

RESULTS

There is an overall decreasing trend in the prevalence of coronary thrombosis with age, where the prevalence of coronary thrombosis was more common in younger age groups and constitutes 59.9% of cases in the age groups less than 45 years in comparison to 42.7% of cases in the ages more than 65 years. The same trend was noticed for the prevalence of cases without evident myocardial fibrosis. On the other hand, the trend was increasing for stenosis without apparent thrombosis and for myocardial fibrosis. In spite of that, the detailed pattern of the prevalence of these pathologies with age did not show a steady, and a continuous change through the whole spanned age groups. Instead, two distinct phases were observed, the first phase represents the cases less than 49 years of age and the second phase represents the cases more than the age of 54 and the age group between 50/54 is what we called the "turn-interval."

CONCLUSION

sThe "turn-interval" was considered as the scientific basis to define the age threshold that differentiates the premature atherosclerotic coronary diseases. Accordingly, it was proposed that male premature coronary artery diseases constituted the cases suffering from the heart attack, or died as a result of cardiac attacks below the age of 49, and the mature disease that affects people who is older than 54 years old.

Monogenic causes of elevated HDL cholesterol and implications for development of new therapeutics

Identification of the CETP, LIPG (encoding endothelial lipase) and APOC3 genes, and ana lysis of rare genetic variants in them, have allowed researchers to increase understanding of HDL metabolism significantly. However, development of cardiovascular risk-reducing therapeutics targeting the proteins encoded by these genes has been less straightforward. The failure of two CETP inhibitors is complex but illustrates a possible over-reliance on HDL cholesterol as a marker of therapeutic efficacy. The case of endothelial lipase exemplifies the importance of utilizing population-wide genetic studies of rare variants in potential therapeutic targets to gain information on cardiovascular disease end points. Similar population-wide studies of cardiovascular end points make apoC-III a potentially attractive target for lipid-related drug discovery. These three cases illustrate the positives and negatives of single-gene studies relating to HDL-related cardiovascular drug discovery; such studies should focus not only on HDL cholesterol and other components of the lipid profile, but also on the effect genetic variants have on cardiovascular end points.

Smoking, alcohol consumption, physical activity, and family history and the risks of acute myocardial infarction and unstable angina pectoris: a prospective cohort study

Background

Few studies investigated the association between smoking, alcohol consumption, or physical activity and the risk of unstable angina pectoris (UAP), while the strength of these associations may differ compared to other coronary diseases such as acute myocardial infarction (AMI). Therefore, we investigated whether the associations of these lifestyle factors with UAP differed from those with AMI. Additionally, we investigated whether these effects differed between subjects with and without a family history of myocardial infarction (MI).

Methods

The CAREMA study consists of 21,148 persons, aged 20-59 years at baseline and randomly sampled from the Maastricht region in 1987-1997. At baseline, all participants completed a self-administered questionnaire. After follow-up of maximally 16.9 years, 420 AMI and 274 UAP incident cases were registered. Incidence rate ratios (RRs) were estimated using Cox proportional hazards models.

Results

For both diseases, smoking increased the risk while alcohol consumption was associated with a protective effect. Associations with both risk factors were stronger for AMI than UAP, although this difference was only statistically significant for smoking. In men, an inverse association was found with physical activity during leisure time which seemed to be stronger for the risk of UAP than of AMI. On the contrary, physical activity during leisure time was associated with an increased risk of both AMI and UAP in women which seemed to be weaker for UAP than for AMI. Except for occupational physical activity in women, no significant interactions on a multiplicative scale were found between the lifestyle factors and family history of MI. Nevertheless, the highest risks were found in subjects with both a positive family history and the most unfavorable level of the lifestyle factors.

Conclusions

The strength of the associations with the lifestyle factors did not differ between AMI and UAP, except for smoking. Furthermore, the effects of the lifestyle factors on the risk of both coronary diseases were similar for subjects with and without a positive family history.

The Role of Polymorphisms Within Paraoxonases (192 Gln/Arg in PON1 and 311Ser/Cys in PON2) in the Modulation of Cardiovascular Risk: A Pilot Study

Paraoxonases (PONs) may exert anti-atherogenic action by reducing lipid peroxidation. We evaluated the influence of 2 polymorphisms within PON1 (192 Gln/ Arg) and PON2 (311 Ser/Cys) genes in 407 young Poles: 273 patients who experienced a first myocardial infarction (MI) under the age of 45 (study group) and 134 healthy volunteers (control group) with a HEART Score ≤2 (low risk). Paraoxonase 1 polymorphism 192Gln/Arg influenced the risk of premature MI (P = .0054). A positive family history of coronary artery disease (CAD) was associated with the 192Arg allele (P = .0107). The association between PON1 genotype (192 Gln/Arg) and low-density lipoprotein cholesterol (LDL-C) (P = .036) levels was also observed. However, we did not find any relationship between polymorphism 311Ser/Cys and CAD risk (P = .418). PON1 polymorphism 192Gln/Arg influenced the risk of premature MI. The association between PON1 genotype (192 Gln/Arg) and serum LDL-C levels may be explained by PON participation in reverse cholesterol transport.

Lack of association between the cholesteryl ester transfer protein gene--TaqIB polymorphism and coronary restenosis following percutaneous transluminal coronary angioplasty and stenting: a pilot study

BACKGROUND

The most widely studied variation at the cholesteryl ester transfer protein (CETP) gene locus is a silent base change called the Thermobius aquaticus IB (TaqIB) polymorphism. TaqIB has been shown to affect levels/activity of CETP, plasma levels of high-density lipoprotein cholesterol (HDL-C), and to contribute to the risk of developing atherosclerosis and coronary heart disease (CHD). Ongoing studies are investigating possible associations between CETP gene polymorphisms and the development of coronary restenosis following percutaneous transluminal coronary angioplasty (PTCA) and stenting.

METHODS AND RESULTS

The primary objective of the present study was to investigate the frequency of TaqIB-polymorphism, and a possible association with post-PTCA coronary restenosis, in 204 Greek patients who had undergone PTCA and stenting. As a secondary objective, the analysis was extended to explore possible interacting or additive effects by various CHD risk factors, and a deletion in the alpha(2B)-adrenergic receptor gene. The frequency of TaqIB was 54%, similar to the frequency of the polymorphism in a group of 35 healthy controls.

CONCLUSIONS

The results from this study do not indicate that the TaqIB variation at the CETP gene locus is a significant predictor for assessing the risk of developing coronary restenosis following PTCA and stenting. This result was not affected when considering any one of the additionally studied factors.

Genetik der koronaren Herzkrankheit und des Herzinfarkts

Aufgrund der hohen Prävalenz der koronaren Herzkrankheit (KHK) und des Herzinfarkts lassen sich in den Anamnesegesprächen oft familiäre Häufungen eruieren. Für die Risikostratifizierung ist es hierbei entscheidend, zwischen sporadischen Fällen und solchen mit „echter“ familiärer Häufung zu unterscheiden. Von einer familiären Prädisposition wird dann ausgegangen, wenn mindestens ein männlicher Verwandter 1. Grades vor dem 55. oder eine weibliche Verwandte 1. Grades vor dem 65. Lebensjahr einen Herzinfarkt erlitten haben oder eine KHK mit signifikanter Stenosierung diagnostiziert wurde. Die aktuelle Übersichtsarbeit möchte wesentliche Studien aufgreifen, aus denen sich das familiäre Risiko für die KHK und den Herzinfarkt ableitet. Darüber hinaus soll ein kurzer Überblick über den aktuellen Stand der genetischen Forschung zu KHK und Herzinfarkt gegeben werden.

Associations between adiposity, family history of CHD and blood pressure in 3–8 year-old children

The purpose of this study was to examine the relationships between overall and central adiposity, a family history of coronary heart disease (FHCHD), and blood pressure (BP) in young children. We were specifically interested in determining whether the relationship between adiposity and BP was modified by a FHCHD. Subjects were 130 (68 males, 62 females) young children (mean age 6.0 years). Indicators of adiposity included the body mass index, waist circumference, skinfold thickness, and body composition determined by dual energy X-ray absorbtiometry (DXA). BP was measured by standard procedures. FHCHD was reported by the parent on a questionnaire. Approximately 19% of the total sample was classified as overweight and almost 50% were classified as prehypertensive (22.4%) or hypertensive (24.8%). In the total sample, 21 of 27 correlations were significant and ranged from 0.03 to 0.52. Correlations for systolic blood pressure appeared to be stronger in female subjects. Most of the correlations for diastolic blood pressure and mean arterial pressure were significant in both sexes and, in general, ranged between 0.30 and 0.50. Overweight status was significantly associated with high BP (crude odds ratio=3.65, 95% confidence intervals 1.40-9.49). There were no significant associations between a positive FHCHD and BP, and the correlations between BMI, WC, and BP were similar in magnitude in subjects with and without a FHCHD. In conclusion, both overall and central adiposity are important determinants of resting BP in young children. A FHCHD was not associated with BP and nor were the associations between adiposity and BP modified by a FHCHD.

Genes and atherosclerosis: at the origin of the predisposition

Atherosclerosis (ATS) is a multifactorial disease caused by the interaction of established or emerging risk factors with multiple predisposing genes that regulate ATS-related processes. This review will discuss the current knowledge concerning the potential role of the genetic variations that could promote and/or accelerate ATS, in both animal models and humans. Allelic polymorphisms or variations of distinct genes that enhance the risk of ATS frequently occur in the general population, but only adequate gene-environment interactions will lead to the disease. The main genes so far studied are involved in the regulation of processes such as endothelial function, antioxidant potential, coagulation, inflammatory response, and lipid, protein and carbohydrate metabolism. The detection of candidate genes associated with ATS could allow, in the near future, earlier interventions in genetically susceptible individuals. Further, large-scale population studies are needed to obtain more information on the specific gene-environment and drug-gene interactions capable of influencing ATS progression.

Lipoprotein lipase gene polymorphisms in Croatian patients with coronary artery disease

Modifications in lipoprotein lipase levels lead to elevated triglycerides and reduced high density lipoprotein (HDL), both of which are risk factors for coronary artery disease (CAD). Hence, we examined the influence of the -93T/G, D9N, N291S, and S447X polymorphisms in the lipoprotein lipase (LPL) gene on CAD risk and lipid levels in Croatian patients with and without angiographically confirmed CAD. The N291S polymorphism was significantly associated with CAD (OR = 0.36; 95% CI = 0.13, 0.99; p = 0.048). This association was only moderately affected by adjusting for various lipids (OR = 0.36; 95% CI = 0.12, 1.08; p = 0.068). HDL2-cholesterol and apolipoprotein A-I levels were significantly higher in non-carriers of the -93T/G and D9N polymorphisms in the CAD group (p = 0.017 and 0.028, respectively). The N291S genetic variant did not show any significant difference between carriers and non-carriers in either group studied for any of the lipids. Lower triglyceride and higher HDL2-cholesterol levels in the control group were associated with carriers of the S447X mutation (p = 0.043 and 0.056, respectively). LPL gene polymorphisms might be involved in predisposition to CAD and determination of lipid profiles.

Family history is a coronary heart disease risk factor in the Second Northwick Park Heart Study

We have estimated the risk of coronary heart disease (CHD) from family history of CHD (FHCHD) in 2827 healthy European middle-aged men, and explored the extent to which this can be explained by classical and genetic risk factors. Men with FHCHD (obtained by questionnaire) had a hazard ratio of CHD of 1.73 (95% confidence interval: 1.30, 2.31) compared to those without FHCHD; after adjusting for classical risk factors this did not change substantially. Those with FHCHD had 2.3% lower Factor VIIc (p = 0.03) and 1.14% higher systolic and 1.21% higher diastolic blood pressure (p = 0.04 and p = 0.02), with evidence of interaction between blood pressure and FHCHD status on risk (p = 0.01). The risk for those with a positive family history who were also current smokers was 3.01 compared to non-smokers without FHCHD, which is greater than the risk posed by smoking or FHCHD alone (1.96 and 2.05 respectively compared to non-smokers without FHCHD), but not significantly different from a multiplicative model (p-value for interaction 0.33). Allele frequencies for 13 candidate gene variants were not significantly different between those with and without FHCHD. In those with FHCHD, current smokers who carried the APOE4 allele (e4+) had a hazard ratio of 5.66 compared to non-smokers who had no FHCHD and were not APOE4+, with a significant interaction between smoking and APOE4 in those with FHCHD p = 0.001. These data demonstrate the complex interaction between genetic and environmental factors in determining CHD risk, and suggest that the causes of the familial clustering of CHD remain largely unexplained.