1. Increased 27-hydroxycholesterol plasma level in men with low high density lipoprotein-cholesterol may circumvent their reduced cell cholesterol efflux rate
- Author
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Eliton Juniro Silva, Valéria S. Nunes, E.S. Parra, Natalia B. Panzoldo, Vanessa Helena de Souza Zago, Patrícia M. Cazita, Eder Carlos da Rocha Quintão, Edna Regina Nakandakare, Camila C. Leança, and Eliana Cotta de Faria
- Subjects
Adult ,Male ,medicine.medical_specialty ,Oxysterol ,medicine.drug_class ,Clinical Biochemistry ,Biochemistry ,Excretion ,chemistry.chemical_compound ,LIPOPROTEÍNAS ,Internal medicine ,polycyclic compounds ,medicine ,Humans ,biology ,Bile acid ,Cholesterol ,Cholesterol, HDL ,Biochemistry (medical) ,Reverse cholesterol transport ,nutritional and metabolic diseases ,Cytochrome P450 ,Biological Transport ,General Medicine ,Healthy Volunteers ,Hydroxycholesterols ,Endocrinology ,Liver ,chemistry ,27-Hydroxycholesterol ,biology.protein ,Microsome ,Female ,lipids (amino acids, peptides, and proteins) - Abstract
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 1.55 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.
- Published
- 2014
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