PATRICIA MIRALDA CAZITA
Projetos de Pesquisa
Unidades Organizacionais
LIM/10 - Laboratório de Lípides, Hospital das Clínicas, Faculdade de Medicina
6 resultados
Resultados de Busca
Agora exibindo 1 - 6 de 6
- Cholesterol metabolism in mice models of genetic hypercholesterolemia(2020) NUNES, Valeria S.; CAZITA, Patricia M.; CATANOZI, Sergio; NAKANDAKARE, Edna R.; QUINTAO, Eder C. R.Monogenic familial hypercholesterolemia is characterized by impaired cellular uptake of apolipoprotein B containing lipoproteins. However, its consequences on whole-body cholesterol metabolism are unclear. We investigated cholesterol metabolism in wild-type mice (control) and in knockout (KO) mice for the low-density lipoprotein receptor (LDLR-KO) and for apolipoprotein E (apoE-KO) containing the genetic basis of the C57BL/6J mice, under a cholesterol-free diet. Cholesterol and ""non-cholesterol"" sterols (cholestanol, desmosterol, and lathosterol) were measured in plasma, tissues, as well as in feces as cholesterol and its bacterial modified products (neutral sterols) using gas chromatography/mass spectrometry, and bile acids were measured by an enzymatic method. Compared to controls, LDLR-KO mice have elevated plasma and whole-body cholesterol concentrations, but total fecal sterols are not modified, characterizing unaltered body cholesterol synthesis together with impaired body cholesterol excretion. ApoE-KO mice presented the highest concentrations of plasma cholesterol, whole-body cholesterol, cholestanol, total fecal sterols, and cholestanol, compatible with high cholesterol synthesis rate; the latter seems attributed to elevated body desmosterol (Bloch cholesterol synthesis pathway). Nonetheless, whole-body lathosterol (Kandutsch-Russel cholesterol synthesis pathway) decreased in both KO models, likely explaining the diminished fecal bile acids. We have demonstrated for the first time quantitative changes of cholesterol metabolism in experimental mouse models that explain differences between LDLR-KO and apoE-KO mice. These findings contribute to elucidate the metabolism of cholesterol in human hypercholesterolemia of genetic origin.
- Metabolism of plasma cholesterol and lipoprotein parameters are related to a higher degree of insulin sensitivity in high HDL-C healthy normal weight subjects(2013) LEANCA, Camila C.; NUNES, Valeria S.; PANZOLDO, Natalia B.; ZAGO, Vanessa S.; PARRA, Eliane S.; CAZITA, Patricia M.; JAUHIAINEN, Matti; PASSARELLI, Marisa; NAKANDAKARE, Edna R.; FARIA, Eliana C. de; QUINTAO, Eder C. R.Background: We have searched if plasma high density lipoprotein-cholesterol (HDL-C) concentration interferes simultaneously with whole-body cholesterol metabolism and insulin sensitivity in normal weight healthy adult subjects. Methods: We have measured the activities of several plasma components that are critically influenced by insulin and that control lipoprotein metabolism in subjects with low and high HDL-C concentrations. These parameters included cholesteryl ester transfer protein (CETP), phospholipid transfer protein (PLTP), lecithin cholesterol acyl transferase (LCAT), post-heparin lipoprotein lipase (LPL), hepatic lipase (HL), pre-beta-1HDL, and plasma sterol markers of cholesterol synthesis and intestinal absorption. Results: In the high-HDL-C group, we found lower plasma concentrations of triglycerides, alanine aminotransferase, insulin, HOMA-IR index, activities of LCAT and HL compared with the low HDL-C group; additionally, we found higher activity of LPL and pre-beta-1HDL concentration in the high-HDL-C group. There were no differences in the plasma CETP and PLTP activities. Conclusions: These findings indicate that in healthy hyperalphalipoproteinemia subjects, several parameters that control the metabolism of plasma cholesterol and lipoproteins are related to a higher degree of insulin sensitivity.
- Omega-6 polyunsaturated fatty acids prevent atherosclerosis development in LDLr-KO mice, in spite of displaying a pro-inflammatory profile similar to trans fatty acids(2012) MACHADO, Roberta M.; NAKANDAKARE, Edna R.; QUINTAO, Eder C. R.; CAZITA, Patricia M.; KOIKE, Marcia K.; NUNES, Valeria S.; FERREIRA, Fabiana D.; AFONSO, Milessa S.; BOMBO, Renata P. A.; MACHADO-LIMA, Adriana; SORIANO, Francisco G.; CATANOZI, Sergio; LOTTENBERG, Ana MariaThe development of atherosclerosis and the inflammatory response were investigated in LDLr-KO mice on three high-fat diets (40% energy as fat) for 16 weeks: trans (TRANS), saturated (SAFA) or omega-6 polyunsaturated (PUFA) fats. The following parameters were measured: plasma lipids, aortic root total cholesterol (TC), lesion area (Oil Red-O), ABCA1 content and macrophage infiltration (immunohistochemistry), collagen content (Picrosirius-red) and co-localization of ABCA1 and macrophage (confocal microscopy) besides the plasma inflammatory markers (IL-6, TNF-alpha) and the macrophage inflammatory response to lipopolysaccharide from Escherichia coli (LPS). As expected, plasma TC and TG concentrations were lower on the PUFA diet than on TRANS or SAFA diets. Aortic intima macrophage infiltration, ABCA1 content, and lesion area on PUFA group were lower compared to TRANS and SAFA groups. Macrophages and ABCA1 markers did not co-localize in the atherosclerotic plaque, suggesting that different cell types were responsible for the ABCA1 expression in plaques. Compared to PUFA, TRANS and SAFA presented higher collagen content and necrotic cores in atherosclerotic plaques. In the artery wall, TC was lower on PUFA compared to TRANS group; free cholesterol was lower on PUFA compared to TRANS and SAFA; cholesteryl ester concentration did not vary amongst the groups. Plasma TNF-alpha concentration on PUFA and TRANS-fed mice was higher compared to SAFA. No difference was observed in IL-6 concentration amongst groups. Regarding the macrophage inflammatory response to LPS, TRANS and PUFA presented higher culture medium concentrations of IL-6 and TNF-alpha as compared to SAFA. The PUFA group showed the lowest amount of the anti-inflammatory marker IL-10 compared to TRANS and SAFA groups. In conclusion, PUFA intake prevented atherogenesis, even in a pro-inflammatory condition.
conferenceObject Plasma 27-hydroxycholesterol/cholesterol Ratio is Increased in Low High Density Lipoprotein-Cholesterol Healthy Subjects(2012) NUNES, Valeria S.; LEANCA, Camila C.; PANZOLDO, Natalia B.; PARRA, Eliane; ZAGO, Vanessa; CAZITA, Patricia M.; NAKANDAKARE, Edna R.; FARIA, Eliana C. de; QUINTAO, Eder C.- Plasma 27-hydroxycholesterol/cholesterol ratio is increased in low high density lipoprotein-cholesterol healthy subjects(2013) NUNES, Valeria S.; LEANCA, Camila C.; PANZOLDO, Natalia B.; PARRA, Eliane; ZAGO, Vanessa; CAZITA, Patricia M.; NAKANDAKARE, Edna R.; FARIA, Eliana C. de; QUINTAO, Eder C. R.Sterol 27-hydroxylase converts cholesterol to 27-hydroxycholesterol (27-OHC) which is widely distributed among tissues and is expressed at high levels in the vascular endothelium and macrophages. There is a continuous flow of this oxysterol from the tissues into the liver; where it is converted to bile acids. Objective: Measure plasma concentrations of 27-OHC in subjects that differ according to their plasma HDL-C concentration. Methods: Healthy men presenting low HDL-C (<1,03 mmol/L), n = 18 or high HDL-C (>1.55 mmol/L), n 18, BMI <30 kg/m(2) were recruited after excluding secondary causes that might interfere with their plasma lipid concentrations such as smoking, heavy drinking and diabetes. Blood samples were drawn after a 12 h fasting period for the measurement of 27-OHC by the combined GC/MS analysis utilizing deuterium-label internal standards. Results: The plasma ratio 27-OHC/total cholesterol (median and range nmoL/mmoL) was 50.41 (27.47-116.00) in the High HDL-C subjects and 6334 (36.46-91.18) in the Low HDL-C subjects (p = 0.0258). Conclusion: Our data indicate that the production of 27-0HC by extrahepatic tissues and its transport to the liver may represent an alternative pathway for a deficient reverse cholesterol transport system when plasma HDL-C is low.
- Increased 27-hydroxycholesterol plasma level in men with low high density lipoprotein-cholesterol may circumvent their reduced cell cholesterol efflux rate(2014) NUNES, Valeria S.; PANZOLDO, Natalia B.; LEANCA, Camila C.; PARRA, Eliane S.; ZAGO, Vanessa S.; SILVA, Eliton J. da; CAZITA, Patricia M.; NAKANDAKARE, Edna R.; FARIA, Eliana C. de; QUINTAO, Eder C. R.Background: HDL is considered the most important mechanism for the excretion of intracellular cholesterol. The liver is the only organ capable to metabolize cholesterol into bile acid. The enzymatic conversion of cholesterol to bile acid is dependent on the cytochrome P450 microsomal system which is also responsible for the generation of oxysterols. The latter's plasma concentrations may reflect the metabolic processes of specific tissues where they are generated. The objective of this study was to investigate in healthy individuals who differ according to their HDL levels the concentration of oxysterols and relate it to the HDL-dependent cell cholesterol efflux rate. Methods: 24-Hydroxycholesterol, 25-hydroxycholesterol, 27-hydroxycholesterol were determined in plasma by GLC/mass spectrometry in 107 healthy subjects with low HDL (HDL-C < 1.03 mmol/l) and high HDL cholesterol (HDL-C > 1.55 mmol/l). HDL-dependent in vitro cell cholesterol efflux rate was measured in 29 cases. Results: No differences were found in plasma oxysterol concentrations between the Low HDL and High HDL groups. There was a significant negative correlation between HDL-C and 27-hydroxycholesterol. Plasma oxysterol concentrations were significantly lower in female than in male subjects. The Low HDL male group had higher 27-hydroxycholesterol than the High HDL male group. Cell cholesterol efflux rate was lower in Low HDL than in High HDL and related inversely with 27-hydroxycholesterol. Conclusion: As compared to High HDL, Low HDL men have increased 27-hydroxycholesterol plasma level that may circumvent their reduced cell cholesterol efflux rate.