| ABCA1 | ATP-binding cassette transporter A1, a cell membrane transporter that facilitates the delivery of cholesterol from cells to lipid-poor apolipoprotein A-I in the extracellular space. |
| ABCG1 | ATP-binding cassette transporter G1, a cell membrane transporter that promotes the transfer of cholesterol from cells to large alpha-migrating, spherical HDL. |
| ApoA-I | Apolipoprotein A-I, the main protein in HDL that accounts for about 70% of the total HDL protein. Atheroprotective lipoprotein; important function in promoting the efflux of cholesterol from cells, and has anti-oxidant and anti-inflammatory properties. |
| ApoA-IMilano | A variant of apoA-I with potent cholesterol efflux capacity. |
| ApoA-I mimetics | Investigational agents that mimic the effect of apoA-I. |
| ApoA-II | Apolipoprotein A-II, the second main protein in HDL that accounts for about 20% of the total HDL protein. Although its main function is not known, apoA-II increases the stability of the HDL particle. |
| ApoA-IV | Apolipoprotein IV, the third most abundant HDL apolipoprotein.ApoA-IV is distinct from apoA-I and apoA-II because a significant proportion of it can dissociate readily from HDL and circulates in a lipid-free form. |
| ApoB | Apolipoprotein B, the main protein component of LDL; atherogenic lipoprotein. |
| Atherogenic | Promoting atherosclerosis |
| Atheroprotective | Protecting against atherosclerosis |
| Atherosclerosis | An inflammatory disorder that is caused by the accumulation of atherogenic lipoproteins in the artery wall. |
| Cholesterol | A soft fatty waxy substance transported in the blood by lipoproteins. It is also present in all cells in the body. Cholesterol is used in producing cell membranes and some hormones, as well as other functions in the body. |
| CETP | Cholesteryl ester transfer protein. This is involved in redistribution of cholesteryl esters from HDL, where they are formed, to other plasma lipoprotein fractions. Plays a major role in the metabolism and remodelling of HDL. |
| Discoidal HDL | Twoor three molecules of apolipoprotein A-I, the main protein component of HDL,plus phospholipid with or without unesterified cholesterol. A nascent form ofHDL that exist only transiently before being converted to spherical HDL. |
| Dyslipidaemia | Abnormalities in lipid metabolism |
| Fibrates | Fibrates mainly reduce triglycerides, as well as reducing LDL cholesterol and increasing HDL cholesterol (by 5-20%). These agents work by activating peroxisome proliferator-activated receptors |
| HDL | High-density lipoprotein, the smallest and most dense of the plasma lipoproteins. HDL are categorised 1)on the basis of density: HDL2<> HDL3 2) on the basis of size: HDL2b>HDL2a>HDL3a>HDL3b>HDL3c 3) on the basis of apolipoprotein composition: A-I HDL (apoA-I only) and A-I/A-II HDL (both apoA-I and apoA-II) 4) on the basis of surface charge: alpha-migrating (spherical HDL) and pre-beta-migrating (discoidal HDL and lipid-poor apoA-I) |
| HDL cholesterol | High-density lipoprotein cholesterol, good cholesterol. HDL cholesterol is a powerful inverse predictor of coronary heart disease. |
| HL | Hepatic lipase, a triglyceride lipase. HDL triglyceride is the preferred substrate. |
| Hypomorphic allele | An allele that reduces the expression of its target protein without eliminating it entirely. |
| LCAT | Lecithin:cholesterol acyltransferase; an enzyme that catalyses the esterification of cholesterol in HDL, and accounts for most of the cholesteryl esters that circulate in the plasma. Plays a major role in the metabolism and remodelling of HDL. |
| LDL cholesterol | Low-density lipoprotein cholesterol; bad cholesterol. |
| Lipid-poor apoA-I | A single molecule of apolipoprotein A-I, the main protein component of HDL, with a few molecules of phospholipid. |
| Lipoprotein | Protein that carries cholesterol in the blood. |
| Lipoprotein(a); Lp(a) | A genetic variant of low-density lipoprotein. An increased level is associated with increased risk of heart disease. |
| Lipoprotein lipase | Atriglyceride lipase that hydrolyses triglycerides in very low-density lipoproteins and chylomicrons in a process that is accompanied by the transfer of phospholipids and apolipoproteins to HDL. |
| LXR | Liver X receptor agonist, an investigational agent that is a potent inducer of ABCA1. |
| Metabolic syndrome | A cluster of abnormalities including central obesity, insulin resistance,dyslipidaemia, mild hypertension and a pro-inflammatory state. |
| Nicotinic acid (niacin) | A form of vitamin B3, a naturally occurring vitamin. Nicotinic acid is the most potent drug available for raising HDL cholesterol (by up to 30%) |
| Plaque | A build-up of fatty substance in the inner lining of the artery. |
| PLTP | Phospholipid transfer protein. This is involved in the transfer of phospholipids between HDL and other plasma lipoprotein fractions. Plays a major role in the metabolism and remodelling of HDL. |
| PON | Paraoxonase, an important anti-oxidant that circulates in the plasma mainly bound to HDL particles. |
| PPAR | Peroxisome proliferator-activated receptor, a nuclear transcription factor. |
| Riskfactors | Conditions that increase the individualÕs risk of developing heart disease. |
| SIP | Sphingosine-1-phosphate (SIP), a sphingolipid constituent of HDL that is responsible for vasodilatory effects. |
| Spherical HDL | Two or three molecules of apolipoprotein A-I, the main protein component of HDL, plus phospholipid, unesterified cholesterol, cholesteryl esters and triglyceride, with or without apolipoprotein II. Most HDL exists in spherical form. |
| SR-B1 | Scavenger receptor B1, an HDL receptor present mainly in the liver (as well as extraheptic tissue), that promotes selective uptake of HDL cholesterol. |
| Total cholesterol | Sum of all cholesterol types in the blood. |
| Triglycerides | A form of fat that comes from food and is also made in the body. |
| VLDL | Very low-density lipoprotein |
| ACCORD | Actionto Control Cardiovascular Risk in Diabetes. A substudy is investigating the effect of combination treatment with fenofibrate and simvastatin on clinical outcome in subjects with or at risk of cardiovascular disease. |
| AIM-HIGH | Atherothrombosis Intervention in Metabolic Syndrome with Low HDL-cholesterol/High Triglyceride and Impact on Global Health Outcomes. This study is evaluating the effect of combination treatment with prolonged-release nicotinic acid and simvastatin on clinical outcome in subjects with cardiovascular disease and low HDL cholesterol and elevated triglycerides. |
| ARBITER 2 and 3 | ARterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol. These studies evaluated the effect of combination treatment with prolonged-release nicotinic acid and a statin for 1-2 years on progression of atherosclerosis in subjects with low HDL cholesterol and coronary heart disease. A surrogate cardiovascular endpoint, carotid intima-media thickness, was the primary endpoint. |
| BIP | BezafibrateInfarction Prevention study, a secondary prevention trial with bezafibrate inmen. |
| DAIS | Diabetes Atherosclerosis Intervention Study, a study in subjects with type 2 diabetes designed to investigate the effect of fenofibrate treatment on angiographic parameters of atherosclerosis. |
| ECHOS | Etude du Cholesterol HDL en Observationnel French Survey |
| FIELD | Fenofibrate Intervention and Event Lowering in Diabetes study in patients with type 2 diabetes (78% with no prior cardiovascular disease). |
| HATS | HDL-Atherosclerosis Treatment Study. This study evaluated the effect of combination treatment with immediate-release nicotinic acid and simvastatin on angiographic measurements of atherosclerosis progression in subjects with coronary heart disease. |
| HHS | Helsinki Heart Study, a primary prevention trial in men with gemfibrozil. |
| ILLUMINATE | Investigationof Lipid Level Management to Understand Its Impact in Atherosclerotic Eventsin subjects with or at high risk of coronary heart disease; a trial involvingtorcetrapib. |
| ILLUSTRATE | Investigation of Lipid Level Management Using Coronary Ultrasound to Assess Reduction of Atherosclerosis by CETP Inhibition [using torcetrapib] and HDL Elevation. |
| PROCAM | Prospective Cardiovascular Mnster study. An observational study that showed an inverse relationship between HDL cholesterol and coronary heart disease risk. |
| RADIANCE | RatingAtherosclerotic Disease Change by Imaging with a New CETP inhibitor [torcetrapib] in patients with heterozygous familial hypercholesterolaemia (RADIANCE 1), or mixed dyslipidaemia (RADIANCE 2). |
| VA-HIT | Veterans Affairs HDL Intervention Trial, a secondary prevention trial with gemfibrozil in men with low levels of LDL cholesterol and HDL cholesterol. |
| Reverse cholesterol transport | Process in which cholesterol (in the form of cholesteryl ester in HDL) is transported from the extra-hepatic tissues to the liver, either for elimination from the body in the bile or for re-incorporation into very-low-density lipoproteins |
