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  4th IAS (Intl AIDS Society) Conference on HIV Pathogenesis, Treatment and Prevention
Sydney, Australia
22-25 July 2007
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Lower prevalence of small, dense low-density lipoprotein (sd-LDL) in hypertriglyceridemic HIV-infected patients than in non-HIV-infected subjects
 
 
  Reported by Jules Levin
4th IAS Conference, July 22-25, 2007, Sydney, Australia
 
A. Trein*, E. Schnaitmann*, W. O. Richter*** HIV center, Stuttgart, Germany, ** Institute for Lipid metabolism, Windach/Munich, Germany
 
INTRODUCTION
Small, dense LDL is regarded to mediate cardiovascular risk of certain hypertriglyceridemias(1, 2). HIV-infection without and with treatment by antiretroviral drug therapy (ART) is associated with an increased prevalence of hypertriglyceridemia. To get more information on the risk of these hypertriglyceridemias we investigated the prevalence of small, dense LDL in serum of HIV-infected subjects compared to non-HIV-infected subjects without and with coronary heart disease.
 
Methods
Fasting blood samples were drawn from 126 HIV-infected subjects, 150 controls without coronary heart disease and 120 controls with coronary heart disease. HIV-infected subjects were recruited at Stuttgart, Germany, non-HIV-infected subjects at Nuremberg, Germany. All patients had elevated triglycerides > 200 mg/dl. The controls were selected from a group of patients (n = 1723) attending cardiological practices. Patients with coronary heart disease had either suffered a myocardial infarction or proven coronary heart disease by coronary angiography. Controls were matched for sex, age and triglyceride concentration. The characteristics of the patients are depicted in table 1.
 
Plasma was obtained by centrifugation of blood for 20 minutes at1500 g. VLDL were separated by ultracentrifugation (Beckman Airfuge, Krefeld, Germany) at a density of 1.006 g/ml (4 hours, 20¡C, 95 000 rpm) using a A-95 rotor with 8 x 20 mm Ultra-Clear tubes. Cholesterol, HDL-cholesterol, and triglycerides in plasma or lipoprotein fractions were determined with commercially available enzymatic assays (SynchronCX5, Beckman Coulter, Krefeld, Germany), apolipoproteinB and lipoprotein (a) by turbimetryusing the same equipment. The antibody against lipoprotein (a) used for the assay was purchased from Technoclone, Vienna, Austria. LDL-cholesterol was determined in the infranatantafter ultracentrifugation by subtracting HDL-cholesterol from total cholesterol concentration. Small, dense LDL-apolipoproteinB-100 was determined after ultracentrifugation in the infranatant with a density > 1.44 g/ml (3).
 
Results
 
Median small, dense LDL-apolipoproteinB-100 was significantly lower in HIV-infected subjects than in matched non-HIV-infected subjects without coronary heart disease and much lower than in non-HIV-infected subjects with coronary heart disease (table 1).
 
Table 1. Lipids, apolipoproteins and small, dense LDL-ApoB-100 (mg/dl) in HIV-infected subjects and non-HIV-infected subjects with and without coronary heart disease (CHD)
 

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Figure 1. Small, dense LDL-ApoB-100 in HIV-infected subjects on different antiretroviral therapies (median)

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CONCLUSION
About one sixth of HIV-infected subjects with triglycerides > 200 mg/dl in serum had elevated small, dense LDL-apolipoproteinB-100 indicating an increased coronary risk. The prevalence of elevated small, denseLDL was not different between groups with different antiretroviral therapies, but was significantly lower than in non-HIV-infected hypertriglyceridemicsubjects with and without coronary heart disease. The determination of small, dense LDL can help to identify patients with high risk due to elevated triglycerides.
 
References
1. Ayyobi, A. F., S. H. McGladdery, M. J. McNeely, et al.: Small, dense LDL and elevated apolipoproteinB are the common characteristics for the three major lipid phenotypes of familial combined hyperlipidemia. Arterioscler. Thromb. Vasc. Biol23 (2003) 1289 -1294
2. Georgieva, A. M., M. M. van Greevenbrock, R. M. Krauss, et al.: Subclasses of low-density lipoprotein and very low-density lipoprotein in familial combined hyperlipidemia: relationship to multiple lipoprotein phenotype. Arterioscler. Thromb. Vasc. Biol24 (2004) 744 -749
3. Menys, V. C., Y. Liu, M. I. Mackness, et al.: Isolation of plasma small-dense low-density lipoprotein using a simple air-driven ultracentrifuge and quantification using immunoassay of apolipoproteinB. Clin. Chem. Lab. Med. 42 (2004) 30 -36