Hyperlipidemia and cardiovascular disease

Lipoprotein Lipase Gene Polymorphisms Are Associated with Myocardial Infarction Risk: A Meta-Analysis

Aims: Many studies and researchers have reported on the genetic association between lipoprotein lipase (LPL) gene polymorphisms and myocardial infarction (MI). The results, however, have been inconclusive. Therefore, we assessed the relationship of LPL gene polymorphisms and MI risk by performing a meta-analysis. Methods: Literature was retrieved through PubMed, Web of Science, the Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), and Embase databases. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the genetic associations between LPL gene polymorphisms and MI risk. A total of nine studies, with 10 individual groups, comprising 2785 cases and 4317 controls were used for this meta-analysis. Results: The allelic (p = 0.0003, OR [95% CI] = 0.86 [0.79-0.93]) and dominant models (p = 0.001, OR [95% CI] = 0.83 [0.73-0.93]), but not the recessive model (p > 0.05) of LPL gene showed that the HindIII variant significantly decreased the risk of MI. In addition, the allelic model (p = 0.04, OR [95% CI] = 0.71 [0.50-0.99]) for the S447X variant showed a significant decrease in the risk of MI. No association was observed between the PvuII variant and MI (p > 0.05). A subgroup analysis based on ethnicity revealed that all of the genetic models (allelic model: p < 0.00001, OR [95% CI] = 0.62 [0.51-0.77]; dominant model: p = 0.003, OR [95% CI] = 0.66 [0.50-0.87]; recessive model (p = 0.02, OR [95% CI] = 0.47 [0.25-0.88]) found an association of the HindIII polymorphism with MI in the Asian, but not in the Caucasian population (p > 0.05). Under the dominant model the HindIII SNP was also shown to be associated with MI risk in the Caucasian population (p = 0.03, OR [95% CI] = 0.87 [0.76-0.99]). In addition, the allelic (p = 0.02, OR [95% CI] = 0.75 [0.59-0.95]) and dominant models (p = 0.02, OR [95% CI] = 0.51 [0.29-0.90]) for S447X demonstrated a significantly decreased MI risk in the Caucasian, but not in the Asian population (p > 0.05). Conclusions: LPL HindIII and S447X polymorphisms, but not PvuII might be the protective factors for MI. To confirm these results, case-control studies with larger numbers of subjects need to be conducted.

White tea and its active polyphenols lower cholesterol through reduction of very-low-density lipoprotein production and induction of LDLR expression

Emerging in vivo and vitro data suggest that white tea extract (WTE) is capable of favourably modulating metabolic syndrome, especially by ameliorating abnormal lipid metabolism. Microarray-based gene expression profiling was performed in HepG2 cells to analyze the effects of WTE from a systematic perspective. Gene Ontology and pathway analysis revealed that WTE significantly affected pathways related to lipid metabolism. WTE significantly downregulated apolipoprotein B (APOB) and microsomal triglyceride transfer protein (MTTP) expression and thereby reduced the production of very-low-density lipoprotein. In the meanwhile, WTE stimulated low-density lipoprotein-cholesterol (LDL-c) uptake through targeting low-density lipoprotein receptor (LDLR), as a consequence of the activation of sterol regulatory element-binding protein 2 (SREBP2) and peroxisome proliferator-activated receptor δ (PPARδ). Furthermore, WTE significantly downregulated triglycerides synthetic genes and reduced intracellular triglycerides accumulation. Besides, we demonstrated that the tea catechins epigallocatechin-3-gallate (EGCG) and epicatechin-3-gallate (ECG) are abundant in WTE and contribute to the regulation of cholesterol metabolism related genes, including LDLR, MTTP and APOB. Our findings suggest white tea plays important roles in ameliorating abnormal lipid metabolism in vitro.

Physical activity and coronary artery calcification in two cohorts of women representing early and late postmenopause

OBJECTIVE

The aim of this study was to examine the association between physical activity (PA) and coronary artery calcification (CAC) among two cohorts of postmenopausal (PM) women representing early and late postmenopause.

METHODS

The cross-sectional relationship between PA and CAC was examined in 173 younger PM women (mean age ± SD, 56.8 ± 2.9 y) from the Women on the Move Through Activity and Nutrition (WOMAN) study and 121 older PM women (mean age ± SD, 73.9 ± 3.8 y) from the Walking Women Follow-up (WWF) study who had complete PA and CAC data. PA was measured objectively using a pedometer over a 7-day period in both cohorts. CAC was assessed using electron beam tomography. Descriptive statistics were used to describe median levels of PA and CAC, as well as proportions of detectable CAC (0 vs > 0).

RESULTS

Fifty-seven percent of WOMAN study participants and 74% of WWF study participants had detectable CAC. The median (interquartile range) CAC score was 1.4 (0-23.3) for participants in the WOMAN study and 38.8 (0-264.4) among WWF study participants. Median (interquartile range) step counts were 6,447 (4,823-8,722) steps per day in the WOMAN study and 5,466 (3,610-7,576) steps per day for WWF study participants. Among WWF study participants, there was a statistically significant inverse association between pedometer steps and CAC (P for trend = 0.002); no association was found among WOMAN study participants.

CONCLUSIONS

Among older PM women, higher levels of PA were associated with lower CAC. However, the relationship was not observed in PM women, likely due to the lower prevalence of CAC in this age group.