PubMed · 10543061
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A Matsunaga, J Sasaki. 1999. [Apolipoprotein E].. https://pubmed.ncbi.nlm.nih.gov/10543061/
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Elevated plasma levels of triacylglycerol-rich lipoproteins (TGRLP) are associated with increased risk of atherogenesis and abnormal reverse cholesterol transport, as illustrated in Type II diabetes. Here we examine the effect of plasma triacylglycerol-rich or cholesteryl ester-rich lipoproteins on the secretion of nascent apolipoprotein E (apoE)-containing lipoprotein E (LpE) particles by human (THP-1) macrophages. As expected, preincubation with low-density lipoprotein (LDL) yielded small but significant increases in total cellular cholesterol content and also the secretion of apoE by macrophages. By contrast, preincubation with TGRLP resulted in higher, dose-dependent, increases in apoE secretion that reflected, but were not dependent on, cellular triacylglycerol accumulation. Secreted apoE was incorporated into a pre-beta migrating LpE fraction that differed in lipid composition and flotation density depending on preincubation conditions. Specifically, the LpE-containing lipoprotein fraction produced by macrophages preincubated with TGRLP was cholesterol-poor, markedly heterogeneous and of higher peak flotation density (d 1.14-1.18) when compared with particles produced after preincubation with LDL. Both the conditioned medium and the isolated (d<1.21) LpE-containing fraction, yielded by macrophages preincubated with TGRLP, seemed poorer at inducing cholesterol efflux than the equivalent fractions from cells preincubated with LDL, as judged by [(3)H]cholesterol efflux from untreated 'naïve' macrophages. Thus, although the interaction of TGRLP with macrophages can enhance apoE output from these cells, the LpE particles produced seem to be relatively inefficient mediators of cholesterol efflux. These factors might contribute to the increased risk of atherosclerosis in individuals with Type II diabetes.
BACKGROUND: Apolipoprotein E (Apo E) plays an important role in atherogenesis. Apo E is polymorphic with three codominant alleles: *2, *3 and *4. Inthis study we evaluated the association between *4 allele and coronary heart disease in hypercholesterolemic subjects from Spain. SUBJECTS AND METHOD: We selected 389 subjects (56% women, mean age 57 years) with hypercholesterolemia who had been on a 6-weeks low fat, low cholesterol diet. Measurement of lipid and lipoprotein concentrations and determination of apoE genotype were carried out in a centralized laboratory. RESULTS: ApoE distribution was as follows: *2/*33%, *3/*3 75%, *3/*4 20%, *4/*4 1% and *2/*41%. Subjects were grouped into *4 (n = 83) or no *4 (n = 303) according to the presence or absence of the *4 allele. Three *2/*4 cases were excluded. Prevalence of coronary artery disease was 15.7% in *4 and 6.9% in no *4 (OR 2.49, 95% CI 1.19-5.22). The relationship persisted significant after correction for age, sex, cardiovascular risk factors and serum concentrations of total cholesterol, HDL-cholesterol and triglycerides by multiple logistic regression analysis (OR2.56, 95% CI 1.03-6.39).Conclusión:In Spain, *4 carriers have a higher prevalence of coronary artery disease than no analysis *4 carriers.
Disposable electrochemical DNA-based biosensors are reviewed; they have been used for the determination of low-molecular weight compounds with affinity for nucleic acids and for the detection of the hybridisation reaction. The first application is related to the molecular interaction between surface-linked DNA and the target pollutants or drugs, in order to develop a simple device for rapid screening of toxic or similar compounds. The determination of such compounds was measured by their effect on the oxidation signal of the guanine peak of calf thymus DNA immobilised on the electrode surface and investigated by chronopotentiometric analysis. The DNA biosensor is able to detect known intercalating compounds, such as daunomycin, polychlorinated biphenyls (PCBs), aflatoxin B1, and aromatic amines. Applicability to river and waste water samples is also demonstrated. Disposable electrochemical sensors for the detection of a specific sequence of DNA were realised by immobilising synthetic single-stranded oligonucleotides onto a graphite screen-printed electrode. The probes became hybridised with different concentrations of complementary sequences present in the sample. The hybrids formed on the electrode surface were evaluated by chronopotentiometric analysis using daunomycin as indicator of the hybridisation reaction. The hybridisation was also performed using real samples. Application to apolipoprotein E (ApoE) is described, in this case samples have to be amplified by PCR and then analysed by DNA biosensor. The extension of such procedures to samples of environmental interest or to contamination of food is discussed.