Evaluation of a semi-automatic isoelectric focusing method for apolipoprotein E phenotyping

A qualitative, semi-automatized method for apolipoprotein E (apoE) phenotyping by isoelectric focusing method has been evaluated on 40 serum samples from patients previously genotyped for apoE, especially as regards concordance with genotyping, but also repeatability and reproducibility of the method, and sample storage. Total concordance with genotyping and good precision criteria, together with its practicability and requirement of a little sample volume, lead to conclude to the usefulness of this method to help clinicians in the diagnosis of dyslipidemic and neurodegenerative diseases.

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Semi-automatic isoelectrofocusing method for apoE phenotyping.

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Total concordance with genotyping.

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Good repeatability and reproducibility.

Determinants of low-density lipoprotein particle diameter during antiretroviral therapy including protease inhibitors in HIV-1-infected patients

BACKGROUND

Lipid disorders are frequent in HIV-1-infected patients taking combination antiretroviral therapy (cART) that includes protease inhibitors (PIs). The presence of small dense low-density lipoprotein particles might be an important predictive marker of cardiovascular disease in this setting. This cross-sectional substudy of the ANRS 126 trial was designed to identify variables influencing LDL diameter.

METHODS

We studied 81 stable HIV-1-infected patients with dyslipidaemia (LDL-cholesterol >4.1 mmol/l, triglycerides <8.8 mmol/l) receiving PI-including cART regimens and no lipid-lowering drugs. LDL diameter was assessed by gradient gel electrophoresis. Relationships between LDL diameter and demographic, metabolic and HIV-related variables were identified by using non-parametric univariate tests and multiple linear regression models.

RESULTS

In univariate analysis, LDL diameter was related to demographic variables, triglyceride (TG) levels, high-density lipoprotein cholesterol (HDL-c) levels, and the numbers and duration of exposure to nucleoside reverse transcriptase inhibitors and PIs. In multivariable linear regression analysis, LDL diameter was negatively associated with the TG level (P<0.0001) and positively associated with the HDL-c level (P<0.0001). For each 1-mmol/l increase in TG, LDL diameter fell by 0.281 nm. Conversely, for each 1-mmol/l increase in HDL-c, LDL diameter rose by 1.175 nm.

CONCLUSIONS

Higher TG and lower HDL-c levels are associated with smaller LDL particle diameter. Small-diameter LDL particles could contribute to early atherogenic processes in HIV-1-infected patients on cART.