Association of lipoprotein-associated phospholipase A2 with coronary calcification among American and Japanese men

Genetic Polymorphism of Lipoprotein-Associated Phospholipase A2 Influences Susceptibility to Gestational Diabetes Mellitus in Chinese Population

Purpose

This paper aims to study the relationship between lipoprotein-associated phospholipase A2 (Lp-PLA2) and GDM (gestational diabetes mellitus) by detecting Lp-PLA2 level and its gene polymorphism.

Patients and Methods

From January to June 2022, 82 GDM patients treated in our hospital were included as an experimental group, and 89 healthy pregnant women during the same period were selected as the control group. Lp-PLA2 concentration and TG, TC, HDL-C, and LDL-C levels were tested with specialized instruments in clinical laboratories. The PLA2G7 gene polymorphisms (rs1805017, rs1805018, and rs76863441) were detected by fluorescent probe method and sequencing.

Results

Lp-PLA2 concentration was significantly higher in GDM group than control group (P<0.05). Among three polymorphism loci of PLA2G7 gene (rs1805017, rs1805018, and rs76863441) the significant associations were only found in GT genotype of rs76863441 loci (P<0.05).

Conclusion

Pregnant women with high levels of Lp-PLA2 concentration are more likely to develop GDM, especially those with PLA2G7 rs76863441 polymorphism. Lp-PLA2 concentration and PLA2G7 rs1805017 polymorphism may be a novel marker for GDM diagnosis and prediction.

Do differences in risk factors explain the lower rates of coronary heart disease in Japanese versus U.S. women?

BACKGROUND

Mortality from coronary heart disease (CHD) in women in Japan is one of the lowest in developed countries. In an attempt to shed some light on possible reasons of lower CHD in women in Japan compared with the United States, we extensively reviewed and analyzed existing national data and recent literature.

METHODS

We searched recent epidemiological studies that reported incidence of acute myocardial infarction (AMI) and examined risk factors for CHD in women in Japan. Then, we compared trends in risk factors between women currently aged 50-69 years in Japan and the United States, using national statistics and other available resources.

RESULTS

Recent epidemiological studies have clearly shown that AMI incidence in women in Japan is lower than that reported from other countries, and that lipids, blood pressure (BP), diabetes, smoking, and early menopause are independent risk factors. Comparing trends in risk factors between women in Japan and the United States, current levels of serum total cholesterol are higher in women in Japan and levels have been similar at least since 1990. Levels of BP have been higher in in Japan for the past 3 decades. Prevalence of type 2 diabetes has been similar in Japanese and white women currently aged 60-69 for the past 2 decades. In contrast, rates of cigarette smoking, although low in women in both countries, have been lower in women in Japan.

CONCLUSIONS

Differences in risk factors and their trends are unlikely to explain the difference in CHD rates in women in Japan and the United States. Determining the currently unknown factors responsible for low CHD mortality in women in Japan may lead to new strategy for CHD prevention.

Plasma lipoprotein-associated phospholipase A2 activity in Alzheimer's disease, amnestic mild cognitive impairment, and cognitively healthy elderly subjects: a cross-sectional study

Introduction

Lipoprotein-associated phospholipase A₂ (Lp-PLA₂) is a circulating enzyme with pro-inflammatory and oxidative activities associated with cardiovascular disease and ischemic stroke. While high plasma Lp-PLA₂ activity was reported as a risk factor for dementia in the Rotterdam study, no association between Lp-PLA₂ mass and dementia or Alzheimer's disease (AD) was detected in the Framingham study. The objectives of the current study were to explore the relationship of plasma Lp-PLA₂ activity with cognitive diagnoses (AD, amnestic mild cognitive impairment (aMCI), and cognitively healthy subjects), cardiovascular markers, cerebrospinal fluid (CSF) markers of AD, and apolipoprotein E (APOE) genotype.

Methods

Subjects with mild AD (n = 78) and aMCI (n = 59) were recruited from the Memory Clinic, University Hospital, Basel, Switzerland; cognitively healthy subjects (n = 66) were recruited from the community. Subjects underwent standardised medical, neurological, neuropsychological, imaging, genetic, blood and CSF evaluation. Differences in Lp-PLA₂ activity between the cognitive diagnosis groups were tested with ANOVA and in multiple linear regression models with adjustment for covariates. Associations between Lp-PLA₂ and markers of cardiovascular disease and AD were explored with Spearman's correlation coefficients.

Results

There was no significant difference in plasma Lp-PLA₂ activity between AD (197.1 (standard deviation, SD 38.4) nmol/min/ml) and controls (195.4 (SD 41.9)). Gender, statin use and low-density lipoprotein cholesterol (LDL) were independently associated with Lp-PLA₂ activity in multiple regression models. Lp-PLA₂ activity was correlated with LDL and inversely correlated with high-density lipoprotein (HDL). AD subjects with APOE-ε4 had higher Lp-PLA₂ activity (207.9 (SD 41.2)) than AD subjects lacking APOE-ε4 (181.6 (SD 26.0), P = 0.003) although this was attenuated by adjustment for LDL (P = 0.09). No strong correlations were detected for Lp-PLA₂ activity and CSF markers of AD.

Conclusion

Plasma Lp-PLA₂ was not associated with a diagnosis of AD or aMCI in this cross-sectional study. The main clinical correlates of Lp-PLA₂ activity in AD, aMCI and cognitively healthy subjects were variables associated with lipid metabolism.

Coronary artery calcification by computed tomography in epidemiologic research and cardiovascular disease prevention

Both American and European guidelines recommend coronary artery calcification (CAC) as a tool for screening asymptomatic individuals at intermediate risk for coronary heart disease (CHD). These recommendations are based on epidemiologic studies mostly in the United States. We review (1) the use of CAC in primary prevention of CHD in the United States, (2) epidemiologic studies of CAC in asymptomatic adults outside of the United States, and (3) international epidemiologic studies of CAC. This review will not consider clinical studies of CAC among patients or symptomatic individuals. US studies have shown that CAC is a strong independent predictor of CHD in both sexes among middle-aged and old age groups, various ethnic groups, and individuals with and without diabetes and that CAC plays an important role in reclassifying individuals from intermediate to high risk. Studies in Europe support these conclusions. The Electron-Beam Tomography, Risk Factor Assessment Among Japanese and US Men in the Post-World-War-II birth cohort (ERA JUMP) Study is the first international study to compare subclinical atherosclerosis, including CAC among Japanese, Japanese Americans, Koreans, and whites. It showed that as compared with whites, Japanese had lower levels of atherosclerosis, whereas Japanese Americans had similar or higher levels. CAC is being increasingly used as a screening tool for asymptomatic individuals in Europe and the United States. CAC is a powerful research tool, because it enables us to describe differences in atherosclerotic burden across populations. Such research could identify factors responsible for differences among populations, which may improve CHD prevention.

Racial variation in lipoprotein-associated phospholipase A₂ in older adults

Background

Lipoprotein-associated phospholipase A₂ (Lp-PLA₂) is a predictor of cardiovascular events that has been shown to vary with race. The objective of this study was to examine factors associated with this racial variation.

Methods

We measured Lp-PLA₂ mass and activity in 714 healthy older adults with no clinical coronary heart disease and not taking dyslipidemia medication. We evaluated the association between race and Lp-PLA₂ mass and activity levels after adjustment for various covariates using multivariable linear regression. These covariates included age, sex, diabetes, hypertension, body mass index, lipid measurements, C-reactive protein, smoking status, physical activity, diet, income, and education level. We further examined genetic covariates that included three single nucleotide polymorphisms shown to be associated with Lp-PLA₂ activity levels.

Results

The mean age was 66 years. Whites had the highest Lp-PLA₂ mass and activity levels, followed by Hispanics and Asians, and then African-Americans; in age and sex adjusted analyses, these differences were significant for each non-White race as compared to Whites (p < 0.0001). For example, African-Americans were predicted to have a 55.0 ng/ml lower Lp-PLA₂ mass and 24.7 nmol/ml-min lower activity, compared with Whites, independent of age and sex (p < 0.0001). After adjustment for all covariates, race remained significantly correlated with Lp-PLA₂ mass and activity levels (p < 0.001) with African-Americans having 44.8 ng/ml lower Lp-PLA₂ mass and 17.3 nmol/ml-min lower activity compared with Whites (p < 0.0001).

Conclusion

Biological, lifestyle, demographic, and select genetic factors do not appear to explain variations in Lp-PLA₂ mass and activity levels between Whites and non-Whites, suggesting that Lp-PLA₂ mass and activity levels may need to be interpreted differently for various races.

Associations of D-dimer and von Willebrand factor with atherosclerosis in Japanese and white men

OBJECTIVE

D-dimer and von Willebrand factor (vWF) are associated with atherosclerosis. We recently reported that in a post-World War II birth cohort, Japanese men in Japan had lower levels of atherosclerosis than white men in the United States (U.S.). We examined whether the differences in D-dimer and vWF levels are associated with differences in atherosclerosis between the two populations.

METHODS AND RESULTS

Population-based samples of 99 Japanese and 100 white American men aged 40-49 years were examined for coronary artery calcification (CAC), carotid intima-media thickness (IMT), D-dimer, vWF, and other factors using a standardized protocol. When compared to white American men,Japanese had similar levels of D-dimer (0.22 +/- 0.28 vs. 0.19 +/- 0.24 microg/L, respectively, P = 0.39) but significantly higher levels of vWF (124.1 +/- 36.6 vs. 91.3 +/- 48.8%, respectively, P < 0.01). Japanese as compared to white American men had significantly lower prevalence of CAC (13.1 vs. 28.0%, P < 0.01, respectively) and significantly lower IMT (0.61 +/- 0.07 vs. 0.66 +/- 0.08 mm, P < 0.01, respectively). Japanese men had a significant positive association of D-dimer with the prevalence of CAC and a negative association of vWF with IMT, whereas white American men did not have any significant associations.

CONCLUSIONS

In men aged 40-49 years, Japanese as compared to white Americans had similar levels of D-dimer and higher levels of vWF although Japanese had a significantly lower prevalence of CAC and IMT. These haemostatic factors are unlikely to explain the difference in atherosclerosis in these populations.

Association of lipoprotein-associated phospholipase A2 with coronary artery disease in African-Americans and Caucasians

CONTEXT

Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is bound predominately to low-density lipoprotein and has been implicated as a risk factor for coronary artery disease (CAD).

OBJECTIVE

We investigated the association between Lp-PLA(2) and CAD in a biethnic African-American and Caucasian population.

DESIGN

Lp-PLA(2) mass, activity, and index, an integrated measure of mass and activity, and other cardiovascular risk factors were determined in 224 African-Americans and 336 Caucasians undergoing coronary angiography.

MAIN OUTCOME MEASURES

We assessed the distribution of Lp-PLA(2) levels and determined the predictive role of Lp-PLA(2) as a risk factor for CAD.

RESULTS

Levels of Lp-PLA(2) mass and activity were higher among Caucasians compared with African-Americans (293 +/- 75 vs. 232 +/- 76 ng/ml, P < 0.001 for mass and 173 +/- 41 vs. 141 +/- 39 nmol/min/ml, P < 0.001 for activity, respectively). However, Lp-PLA(2) index was similar in the two groups (0.61 +/- 0.17 vs. 0.64 +/- 0.19, P = NS). In both ethnic groups, Lp-PLA(2) activity and index was significantly higher among subjects with CAD. African-American subjects with CAD had significantly higher Lp-PLA(2) index than corresponding Caucasian subjects (0.69 +/- 0.20 vs. 0.63 +/- 0.18, P = 0.028). In multivariate regression analyses, after adjusting for other risk factors, Lp-PLA(2) index was independently (odds ratio 6.7, P = 0.047) associated with CAD in African-Americans but not Caucasians.

CONCLUSIONS

Lp-PLA(2) activity and index was associated with presence of CAD among African-Americans and Caucasians undergoing coronary angiography. The findings suggest an independent impact of vascular inflammation among African-Americans as contributory to CAD risk and underscore the importance of Lp-PLA(2) as a cardiovascular risk factor.

Association of Lp-PLA(2) activity with allele-specific Lp(a) levels in a bi-ethnic population

OBJECTIVES

Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) and lipoprotein(a) [Lp(a)] have been implicated as cardiovascular disease risk factors, and are differentially regulated across ethnicity. We investigated the association between Lp-PLA(2) activity and allele-specific apolipoprotein(a) [apo(a)] levels in a bi-ethnic population.

METHODS

Lp-PLA(2) activity, Lp(a) and allele-specific apo(a) levels were determined in 224 African Americans and 336 Caucasians.

RESULTS

Lp-PLA(2) activity level was higher among Caucasians compared to African Americans (173 + or - 41 nmol/min/ml vs. 141 + or - 39 nmol/min/ml, P<0.001), and positively associated with Lp(a), total and LDL cholesterol, triglyceride, apolipoprotein B-100, and negatively with HDL cholesterol levels in both ethnic groups. The association between Lp-PLA(2) activity and Lp(a) was stronger among African Americans compared to Caucasians (R=0.238, beta(1)=3.48, vs. R=0.111, beta(1)=1.93, respectively). The Lp-PLA(2) activity level was significantly associated with allele-specific apo(a) levels for smaller (<26 K4 repeats) apo(a) sizes in both ethnic groups (P=0.015 for African Americans, P=0.038 for Caucasians). In contrast, for larger (>26 K4 repeats) apo(a) sizes, high Lp-PLA(2) activity levels were associated with higher allele-specific apo(a) levels in African Americans (P=0.009), but not in Caucasians.

CONCLUSION

The association between Lp-PLA(2) activity and allele-specific apo(a) levels differs across African American-Caucasian ethnicity.

Dietary, lifestyle, and clinical predictors of lipoprotein-associated phospholipase A2 activity in individuals without coronary artery disease

BACKGROUND

Elevated lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) may be positively associated with risk of coronary artery disease, yet little is known about potentially modifiable factors related to Lp-PLA(2).

OBJECTIVE

The aim of this study was to determine dietary, lifestyle, and clinical measures associated with Lp-PLA(2) activity.

DESIGN

We measured Lp-PLA(2) activity in 853 female participants of the Nurses' Health Study and 878 male participants of the Health Professionals Follow-Up Study who were free of cancer and cardiovascular disease. Multivariable linear regression models were used to assess the relation between potentially modifiable factors and Lp-PLA(2).

RESULTS

The replacement of 5% of energy from carbohydrates with energy from protein was associated with 2.2 nmol . min(-1) . mL(-1) lower levels of Lp-PLA(2) (95% CI: -3.1, -0.4) activity, and every 15-g/d increase in alcohol consumption was associated with 4.4 nmol . min(-1) . mL(-1) lower levels of Lp-PLA(2) activity (95% CI: -6.4, -2.4). Smoking (beta = 10.2; 95% CI: 4.8, 15.5), being overweight (beta = 7.5; 95% CI: 3.6, 11.3), aspirin use (beta = 6.0; 95% CI: 2.1, 10.0), hypercholesterolemia (beta = 15.0; 95% CI: 11.3, 18.8), and age (beta = 2.5; 95% CI: 1.34, 3.74) were associated with elevated Lp-PLA(2) activity, whereas postmenopausal hormone use (beta = -15.8; 95% CI: -19.4, -12.1) and cholesterol medication use (beta = -9.6; 95% CI: -18.2, -1.1) were inversely associated.

CONCLUSION

We found that not smoking, use of postmenopausal hormones, having a body mass index (in kg/m(2)) < or =25, increased alcohol consumption, and increased protein consumption all represent potential modifiable factors that may favorably influence Lp-PLA(2) activity.

Association of Lipoprotein-Associated Phospholipase A2 Mass and Activity with Coronary and Aortic Atherosclerosis: Findings from the Dallas Heart Study

Background: Our aim was to characterize the association of lipoprotein-associated phospholipase A2 (Lp-PLA2) with coronary and aortic atherosclerosis in a large population-based study.

Methods: Lp-PLA2 mass and activity were measured in 2171 subjects 30–65 years old participating in the Dallas Heart Study. We examined the association of Lp-PLA2 levels with 3 atherosclerosis phenotypes: coronary artery calcium (CAC) measured by electron-beam computed tomography and abdominal aortic plaque (AAP) and aortic wall thickness (AWT) measured by magnetic resonance imaging.

Results: CAC and AAP were detected in 21% and 40% of subjects, respectively, and mean AWT (SD) was 1.70 (0.32) mm. In univariable analyses, Lp-PLA2 mass (but not activity) was higher in both men (P = 0.04) and women (P = 0.02) with detectable CAC. Lp-PLA2 mass and activity were higher (P = 0.004 and P = 0.01, respectively) and AWT was greater (P &lt; 0.001 and P = 0.02, respectively) in women with aortic atheroma, but not in men. After adjustment for traditional atherosclerosis risk factors and C-reactive protein concentrations, Lp-PLA2 mass and activity were not associated with AAP or AWT in either sex, but Lp-PLA2 mass remained modestly associated with detectable CAC only in men (odds ratio 1.20 per 1 standard deviation increase, 95% CI 1.01–1.42, P = 0.04).

Conclusions: Although Lp-PLA2 mass was independently associated with CAC in men, it was not associated with AAP or AWT in men or with any of the atherosclerosis phenotypes in women. These findings suggest that if Lp-PLA2 independently influences clinical events, it does so by promoting atherosclerotic plaque instability rather than by stimulating atherogenesis.