Association and linkage disequilibrium analyses of APOE polymorphisms in atherosclerosis.

BACKGROUND: Apolipoprotein E (apo E) plays a major role in lipid metabolism, and its genetic variations have been associated with cardiovascular risk. The objective of this study was to investigate the influence of the APOE promoter (-491 A/T, -427 T/C and -219 G/T) and coding region (APOE epsilon2/epsilon3/epsilon4) polymorphisms in atherosclerosis disease by association and linkage disequilibrium analyses. MATERIALS AND METHODS: We analyzed these polymorphisms in a sample of 286 subjects with atherosclerosis disease: 153 subjects with atherothrombotic stroke (ATS) and 133 subjects with ischemic heart disease (IHD); and in two control groups, 103 newborns and 114 elderly subjects. RESULTS: The epsilon4 allele was associated with more severe carotid stenosis in the ATS group, being the percentages of epsilon4 carriers 26.7% and 11.4% for the higher and lower carotid stenosis groups, respectively (p=0,066). The -491 T/T IHD subjects presented higher vessel scores than subjects A/A and A/T genotypes at that position (p=0,041), and the frequencies of -2 (5.1% versus 14.1%, p=0,060) and -427C (10.3% versus 24.4%, p=0,019) alleles were lower in IHD subjects with higher extent score versus lower extent score. The epsilon2 allele was in linkage disequilibrium with the -427C allele in all studied groups, and the -219T allele was associated with the epsilon4 allele in the IHD group. CONCLUSION: In summary, the epsilon2 allele was in linkage disequilibrium with the -427C allele in all studied groups, and only slight associations between the analyzed APOE polymorphisms in the promoter and in the coding region and carotid and coronary vascular disease have been observed.

Serum chitotriosidase activity, a marker of activated macrophages, predicts new cardiovascular events independently of C-reactive protein.

BACKGROUND: C-reactive protein (CRP) is a well-established inflammation marker associated with cardiovascular risk. However, its relationship with chitotriosidase activity, a novel marker of activated macrophages highly expressed in human atherosclerotic plaques, is unknown. Therefore, we sought to determine if serum chitotriosidase activity predicts the risk of new coronary events, and to analyze its relationship with CRP. METHODS: Chitotriosidase activity and genotype, and high-sensitivity CRP were measured at baseline in 133 middle-aged men with stable coronary heart disease, who were followed for the occurrence of cardiovascular morbidity and mortality for a mean of 4 years. We studied the value of these proteins in predicting the risk of new cardiovascular events. RESULTS: Serum chitotriosidase activity was higher in the group of subjects with a prespecified major event (nonfatal myocardial infarction, nonfatal ischemic stroke, coronary revascularization procedures and death from cardiovascular causes) than in the group of subjects without event, 116 +/- 30.9 nmol/ml x h versus 74.2 +/- 5.69 nmol/ml x h, respectively (p = 0.042). The baseline values of chitotriosidase activity and CRP did not correlate (R = 0.104, p = 0.266), but both parameters were related to a reduction of event-free survival in the Cox regression analysis, with relative risks of 2.61 (p = 0.060) and 2.56 (p = 0.019), respectively. Chitotriosidase activity seems to be a better marker for new events occurring after 2 years of follow-up than in the first 2 years. Both markers had similar predictive values, and their sensitivity (64%) and negative predictive value (84%) were improved when combined. CONCLUSIONS: Our results suggest that serum chitotriosidase activity predicts the risk of new cardiovascular events in the following 4 years. This new cardiovascular risk marker is independent of CRP and, when combined, the prediction of the risk of new cardiovascular events and the identification of a lower risk group seem to improve.

Genetic variation in the hepatic lipase gene is associated with combined hyperlipidemia, plasma lipid concentrations, and lipid-lowering drug response.

BACKGROUND: Combined hyperlipidemia (CHL) is a very frequent dyslipidemia, being lipid-lowering drugs often necessary in its management. Some genetic loci have been associated with CHL, and modulation of lipid-lowering treatment by genetic polymorphisms has been reported. We have investigated whether common polymorphisms in the hepatic lipase gene (LIPC) influence the baseline lipid concentration and the response to atorvastatin or bezafibrate in patients with CHL. METHODS: Two genetic polymorphisms in LIPC (-514C-->T and +651A-->G) were determined by polymerase chain reaction and restriction analysis in 118 subjects of the ATOMIX (Atorvastatin in Mixed dyslipidemia) study who were randomized to treatment with either atorvastatin or bezafibrate and in 114 normolipidemic controls. RESULTS: The -514T allele frequency was higher in the ATOMIX group (0.297) than in the control group (0.193) (P = .01). The -514T allele carriers in the control group showed higher high-density lipoprotein cholesterol (HDL-C) concentrations than the -514C homozygotes, 50.8 +/- 1.86 versus 45.9 +/- 1.40 mg/dL (P = .02). The +651G carriers in the ATOMIX group showed lower total cholesterol and low-density lipoprotein cholesterol than the +651A homozygotes, 274 +/- 3.72 and 181 +/- 3.50 mg/dL versus 289 +/- 4.0 and 194 +/- 3.76 mg/dL, respectively (P < .01). Homozygotes for the -514C allele on bezafibrate treatment had greater decrease in triglycerides and greater increase in HDL-C than -514T allele carriers after 12 months of bezafibrate treatment, -39.4% and +35.8% versus -25.5% and +20.4%, respectively (P = .080 and P = .007, respectively). CONCLUSIONS: A higher frequency of the -514T allele of LIPC suggests a role of this locus in the pathogenesis of CHL. The -514T allele is associated with higher HDL-C concentration in normolipidemic population. The -514C-->T polymorphism modulates the lipid-lowering response to bezafibrate, with a better effect in homozygous CC subjects.

Expression and functional characterization of mutated glucocerebrosidase alleles causing Gaucher disease in Spanish patients.

BACKGROUND: Gaucher disease (GD) is a heterogeneous disease characterized by an impaired activity of the lysosomal glucocerebrosidase. This heterogeneity is attributed in part to the existence of a large number of mutations in the corresponding gene. SUBJECTS AND METHODS: To establish genotype-phenotype relationships, we analyzed the residual enzyme activities of six naturally occurring mutations found in Spanish population in the glucocerebrosidase gene [c.160G > A (V15M), c.485T>C (M123T), c.914C>T (P266L), c.1124T>C (L336P), c.1207A>C (S364R) and c.1510-1512delTCT (S465del)]. The mutated genes were subcloned into the mammalian expression vector pCR 3.1 and expressed by transient transfection in COS cells. The enzymatic activity of the expressed protein were measured and compared with the wild-type human glucocerebrosidase cDNA. Also, two previously alleles, c.1226A>G (N370S) and c.1448T>C (L444P), were used for comparative purposes. RESULTS: The residual activity of the expressed proteins using the synthetic substrate (4-methylumbelliferyl-beta-D-glucopyranoside, 4MU-Glu) ranged from 5.5% (for the 3-bp deletion) to 42.7% (for S364R mutation) of the activity of the wild-type enzyme. CONCLUSION: The present analyses may help to better understand the molecular basis and the pathogenesis of Gaucher disease. However, results of expression of mutated enzymes are necessary but not sufficient to explain the ultimate clinical outcome of Gaucher disease.

Serum chitotriosidase activity is increased in subjects with atherosclerosis disease.

OBJECTIVE: This study was undertaken to analyze the relation between serum activity of chitotriosidase enzyme, a protein synthesized exclusively by activated macrophages, and atherosclerotic lesion extent in subjects with atherothrombotic stroke (ATS) and in subjects with ischemic heart disease (IHD). METHODS AND RESULTS: We assayed the serum chitotriosidase activity and a common chitotriosidase gene polymorphism that causes deficiency in chitotriosidase activity in 3 Spanish populations, ATS (n=153), IHD (n=124), and control (n=148) subjects. Statistical differences were found in serum chitotriosidase activity between ATS (88.1+/-4.6 nmol/mL. h, P<0.0001) and IHD subjects (79.0+/-6.3, P=0.002) versus control group (70.9+/-5.2). These observed differences were not attributable to a distinct allelic or genotype distribution. The extension of the atherosclerotic lesion in carotids of ATS subjects was measured by duplex sonography. Chitotriosidase activities were 66.9+/-9.6, 88.7+/-8.3, and 107.7+/-11.8 for subjects with carotid stenosis 60%, respectively. Statistical differences were observed between subjects with major and intermediate stenosis grade compared with subjects with minor stenosis, P=0.005 and P=0.016, respectively. CONCLUSIONS: Serum chitotriosidase activity is significantly increased in individuals suffering from atherosclerosis disease and is related to the severity of the atherosclerotic lesion, suggesting a possible role as atherosclerotic extent marker.