Fernanda Alexandre

Efeitos da atorvastatina e do polimorfismo T-786C do gene eNOS sobre parâmetros do metabolismo lipídico plasmático

BACKGROUND Endothelial nitric oxide synthase (eNOS) activity may be modulated by high-density lipoprotein cholesterol (HDL-C), statins or polymorphisms, such as the T-786C of eNOS. OBJECTIVE This study aimed at evaluating if the T-786C polymorphism is associated with changes of atorvastatin effects on the lipid profile, on the concentrations of metabolites of nitric oxide (NO) and of high sensitivity C-reactive protein (hsCRP). METHODS Thirty male volunteers, asymptomatic, aged between 18 and 56 years were genotyped and classified according to absence (TT, n = 15) or presence (CC, n = 15) of the polymorphism. They were randomly selected for the use of placebo or atorvastatin (10 mg/day/14 days). After each treatment lipids, lipoproteins, HDL2 and HDL3 composition, cholesteryl ester transfer protein (CETP) activity, metabolites of NO and hsCRP were evaluated. RESULTS The comparisons between genotypes after placebo showed an increase in CETP activity in a polymorphism-dependent way (TT, 12±7; CC, 22±12; p < 0.05). The interaction analyses between treatments indicated that atorvastatin has an effect on cholesterol, LDL, nitrite and lipid-protein ratios (HDL2 and HDL3) (p < 0.001) in both genotypes. Interestingly, we observed genotype/drug interactions on CETP (p < 0.07) and lipoprotein (a) (Lp(a)) (p < 0.056), leading to a borderline decrease in CETP, but with no effect on Lp(a). HsCRP showed no alteration. CONCLUSION These results suggest that statin treatment may be relevant for primary prevention of atherosclerosis in patients with the T-786C polymorphism of eNOS, considering the effects on lipid metabolism.

Development of a clinical laboratory data base of hyper and hypo alpha lipoproteins in Campinas-SP and neighboring region

INTRODUCTION: The development of research for diagnosis, prevention and treatment of atherosclerotic cardiovascular disease is of utmost importance due to the fact that it is the main cause of morbidity and mortality in Brazil. OBJECTIVE: To demonstrate the phases of the selection process for candidates with the aim to develop a clinical-laboratorial database of hyper alpha lipoproteinemic patients (hyper A) - high density lipoprotein cholesterol (HDL-C) ≥ 68 mg/dl) and hypo alpha lipoproteinemic patients (hypo A) - HDL-C < 39 mg/dl. MATERIAL AND METHODS: The volunteers were contacted after selection of lipid profiles from individuals treated at the Sistema Unico de Saude (SUS), Campinas-SP and neighboring area. Afterwards, the selected patients went through blood collection, clinical examinations and answered questionnaires on dietary frequency and physical activity. After this preliminary evaluation, some individuals were convened to another blood collection and, subsequently, were submitted to an ultrasonographic exam of the carotid arteries. RESULTS: Only 0.6% and 0.3% from 598,288 lipid profiles were selected for hyper A and hypo A groups, respectively, including gender disparity. Lack of effective questionnaires (75%), missing calls (60%) and non-inclusion were the major hindrances in the construction of this database. DISCUSSION: The difficulties to obtain eligible candidates were also due to the low prevalence of both groups hypo A and hyper A and the high prevalence of pathologies that contribute to non-genetic variations of HDL-C. CONCLUSION: In spite of the obstacles in the development of this database, this study brought about several scientific publications. Furthermore, the development of molecular analyzes and functionality will shortly generate other findings, contributing to the diagnosis and follow-up of HDL dyslipidemias.

Avaliação da eficiência da radiação ultravioleta na esterilização de embalagens plásticas

O uso da radiacao ultravioleta e um dos varios processos fisicos que podem ser utilizados para a esterilizacao ou na higienizacao de superficies que irao entrar em contato com alimentos. Objetivou-se, nesta pesquisa a avaliacao da eficiencia da radiacao ultravioleta (UV) na esterilizacao de superficies de embalagens para alimentos visando a reducao da contaminacao microbiologica. Tampas e filmes plasticos foram irradiados em uma fonte de ultravioleta emitindo comprimentos de ondas a 254 nm, no interior de uma câmara especialmente projetada para este estudo, atraves de um delineamento fatorial para testar as variaveis: tempo de exposicao e intensidade de irradiacao (distância da fonte). Avaliou-se o numero de reducoes decimais de esporos de Bacillus subtilis inoculados na superficie das embalagens. As reducoes decimais obtidas nao foram altas, variaram de 0,21 a 2,47, mas o uso da lâmpada UV foi altamente eficiente para tempo de exposicao superior a 30 s e distância minima de 20 cm da fonte, causando a reducao total da carga microbiana inoculada.

p.Q192R SNP of PON1 seems not to be Associated with Carotid Atherosclerosis Risk Factors in an Asymptomatic and Normolipidemic Brazilian Population Sample

Background Evidences suggest that paraoxonase 1 (PON1) confers important antioxidant and anti-inflammatory properties when associated with high-density lipoprotein (HDL). Objective To investigate the relationships between p.Q192R SNP of PON1, biochemical parameters and carotid atherosclerosis in an asymptomatic, normolipidemic Brazilian population sample. Methods We studied 584 volunteers (females n = 326, males n = 258; 19-75 years of age). Total genomic DNA was extracted and SNP was detected in the TaqMan® SNP OpenArray® genotyping platform (Applied Biosystems, Foster City, CA). Plasma lipoproteins and apolipoproteins were determined and PON1 activity was measured using paraoxon as a substrate. High-resolution β-mode ultrasonography was used to measure cIMT and the presence of carotid atherosclerotic plaques in a subgroup of individuals (n = 317). Results The presence of p.192Q was associated with a significant increase in PON1 activity (RR = 12.30 (11.38); RQ = 46.96 (22.35); QQ = 85.35 (24.83) μmol/min; p < 0.0001), HDL-C (RR= 45 (37); RQ = 62 (39); QQ = 69 (29) mg/dL; p < 0.001) and apo A-I (RR = 140.76 ± 36.39; RQ = 147.62 ± 36.92; QQ = 147.49 ± 36.65 mg/dL; p = 0.019). Stepwise regression analysis revealed that heterozygous and p.192Q carriers influenced by 58% PON1 activity towards paraoxon. The univariate linear regression analysis demonstrated that p.Q192R SNP was not associated with mean cIMT; as a result, in the multiple regression analysis, no variables were selected with 5% significance. In logistic regression analysis, the studied parameters were not associated with the presence of carotid plaques. Conclusion In low-risk individuals, the presence of the p.192Q variant of PON1 is associated with a beneficial plasma lipid profile but not with carotid atherosclerosis.

Reference values for high-density lipoprotein particle size and volume by dynamic light scattering in a Brazilian population sample and their relationships with metabolic parameters.

BACKGROUND Current data indicate that the size of high-density lipoprotein (HDL) may be considered an important marker for cardiovascular disease risk. We established reference values of mean HDL size and volume in an asymptomatic representative Brazilian population sample (n=590) and their associations with metabolic parameters by gender. METHODS Size and volume were determined in HDL isolated from plasma by polyethyleneglycol precipitation of apoB-containing lipoproteins and measured using the dynamic light scattering (DLS) technique. RESULTS Although the gender and age distributions agreed with other studies, the mean HDL size reference value was slightly lower than in some other populations. Both HDL size and volume were influenced by gender and varied according to age. HDL size was associated with age and HDL-C (total population); non- white ethnicity and CETP inversely (females); HDL-C and PLTP mass (males). On the other hand, HDL volume was determined only by HDL-C (total population and in both genders) and by PLTP mass (males). CONCLUSIONS The reference values for mean HDL size and volume using the DLS technique were established in an asymptomatic and representative Brazilian population sample, as well as their related metabolic factors. HDL-C was a major determinant of HDL size and volume, which were differently modulated in females and in males.

HDL Size is More Accurate than HDL Cholesterol to Predict Carotid Subclinical Atherosclerosis in Individuals Classified as Low Cardiovascular Risk

Background Misclassification of patients as low cardiovascular risk (LCR) remains a major concern and challenges the efficacy of traditional risk markers. Due to its strong association with cholesterol acceptor capacity, high-density lipoprotein (HDL) size has been appointed as a potential risk marker. Hence, we investigate whether HDL size improves the predictive value of HDL-cholesterol in the identification of carotid atherosclerotic burden in individuals stratified to be at LCR. Methods and Findings 284 individuals (40–75 years) classified as LCR by the current US guidelines were selected in a three-step procedure from primary care centers of the cities of Campinas and Americana, SP, Brazil. Apolipoprotein B-containing lipoproteins were precipitated by polyethylene glycol and HDL size was measured by dynamic light scattering (DLS) technique. Participants were classified in tertiles of HDL size (<7.57; 7.57–8.22; >8.22 nm). Carotid intima-media thickness (cIMT) <0.90 mm (80th percentile) was determined by high resolution ultrasonography and multivariate ordinal regression models were used to assess the association between cIMT across HDL size and levels of lipid parameters. HDL-cholesterol was not associated with cIMT. In contrast, HDL size >8.22 nm was independently associated with low cIMT in either unadjusted and adjusted models for age, gender and Homeostasis Model Assessment 2 index for insulin sensitivity, ethnicity and body mass index (Odds ratio 0.23; 95% confidence interval 0.07–0.74, p = 0.013). Conclusion The mean HDL size estimated with DLS constitutes a better predictor for subclinical carotid atherosclerosis than the conventional measurements of plasma HDL-cholesterol in individuals classified as LCR.

Asymptomatic individuals with high HDL-C levels overexpress ABCA1 and ABCG1 and present miR-33a dysregulation in peripheral blood mononuclear cells.

Considering the growing knowledge and perspectives on microRNAs (miRNAs) that control high-density lipoprotein cholesterol (HDL-C) levels and metabolism, this study aimed at evaluating whether hsa-miR-33a and hsa-miR-128a are differentially expressed in peripheral blood mononuclear cells from asymptomatic individuals with low and high HDL-C, as well as at investigating the potential relationships with ATP binding cassete transporter A1 (ABCA1) expression, cholesterol efflux capacity and other parameters related with reverse cholesterol transport. In addition, the associations with cardiovascular risk were investigated by carotid-intima media thickness (cIMT). Asymptomatic volunteers of both genders (n=51) were classified according to HDL-C (mg/dL) in hypoalphalipoproteinemics (hypo, HDL-C ≤3 9), hyperalphalipoproteinemics (hyper, HDL-C ≥ 68) and controls (CTL, HDL-C ≥ 40<68). cIMT, lipids, lipoproteins, HDL size and volume, C reactive protein and insulin were determined, as well as the activities of several proteins and enzymes related to HDL metabolism. In a subgroup of 19 volunteers the cellular cholesterol efflux and HDL composition were determined. Total RNA was extracted from peripheral blood mononuclear cells for relative quantification experiments. Hypo volunteers presented significantly higher levels of triglycerides, VLDL-C and insulin; in addition, HDL size and volume decreased when compared with CTL and hyper. Regarding gene expression analysis, the hyper group presented a decrease of 72% in hsa-miR-33a and higher mRNA expression of ABCA1 and ABCG1 when compared with CTL. No significant differences in hsa-miR-128a expression, cholesterol efflux, cIMT or plaques were found. Further studies are necessary to elucidate the mechanisms underlying the complex miRNA network, regulating cellular cholesterol homeostasis in humans and its clinical repercussions.