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2-Cholestrol ester transfer protein:(ApoD)
Apo D is associated with HDL and facilitates the transfer of cholesterol esters to VLDL and chylomicrons remnants in exchange for triacylglycerol.
Cholesterol is a substance used to help digest fats, strengthen cell membranes and make hormones. When blood cholesterol reaches high levels, it can build up on artery walls, increasing the risk of blood clots, heart attack and stroke. There is strong evidence that lowering cholesterol concentrations reduces mortality from coronary heart disease (CHD).75,76 The West of Scotland Coronary Prevention Study (WOSCOPS) found that cholesterol-lowering drug therapy significantly reduced the incidence of myocardial infarction and death from cardiovascular causes without adversely affecting the risk of death from non-cardiovascular causes in men with moderate hypercholesterolemia and no history of myocardial infarction.77,78
Several guidelines have been drawn up giving different advice for managing hyperlipidaemia. The recent National Service Framework's guidelines on prevention of coronary heart disease in clinical practice suggest a cholesterol target of less than 5.0 mmol/l for both primary and secondary prevention.79
HDL-cholesterol is the fraction of cholesterol that removes cholesterol from the blood by carrying it to the liver where it is metabolised. HDL-cholesterol is inversely and independently associated with the risk of developing CHD,80,81 and low levels of HDL-cholesterol are also associated with a worse prognosis after myocardial infarction.82 A recent prospective study on middle-aged British men showed that higher levels of HDL-cholesterol were associated with a significant decrease in risk of nonfatal stroke.83 Modifiable risk factors such as smoking, alcohol consumption, raised body mass index and blood pressure are known to lower the concentrations of HDL-cholesterol. Attention is generally recommended for HDL-cholesterol concentrations below 1 mmol/l.
Coronary heart disease risk is influenced by elevated cholesterol, low density lipoprotein-c (LDL-C), triglycerides, hypertension cigarette smoking, Low HDL-C levels, family history, life habits, increased Lipoprotein (a), homo-cysteine 84, c-reactive protein, fibrinogen 85, and haematacrit 86. A recent study 87 has shown that risk of death due to cardiovascular disease increases with raised levels of non-HDL-C. Non-HDL –C may also be a better parameter for cardiovascular risk assessment and as target for therapy 88.
NON HDL CHOLESTEROL
Non-HDL-C is defined as the difference between total cholesterol (TC) and HDL-C and contains all known and potentially atherogenic lipid particles 88, including LDL-C, Lipoprotein (a), intermediate–density lipoprotein cholesterol and very low density lipoprotein cholesterol remnants, therefore a good and potential predictor of risk for cardiovascular diseases. Considering the importance of non-HDL-C, we carried out this cross-sectional study to evaluate the levels of non-HDL-C, a newly recognized risk factor, in patients of IHD.
Subclasses of HDL
With the use of segmented gradient gel electrophoresis (SGGE), a lab technique for separating and identifying blood components, lipoproteins can be sub classified to more accurately indicate cardiovascular risk. There are five subclasses of HDL — 2a, 2b, 3a, 3b, and 3c — but only 2b is cardio protective. HDL 2b is the most efficient form of HDL in reverse cholesterol transport, which vacuums the lipids from the endothelium.14
Patients with low total HDL levels often have low levels of HDL 2b. When levels of total HDL are between 40 and 60, cardio protective levels of HDL 2b are minimal. However, when levels of total HDL are greater than 60, levels of HDL 2b predominate and efficient reverse cholesterol transport takes place. This protects the coronary arteries from disease. The other subclasses of HDL are not capable of reverse cholesterol transport and therefore are not cardioprotective. Levels of HDL 2b can be increased by niacin supplements, but not by statin drugs (i.e., HMG CoA reductase inhibitors, such as simvastin or lovastatin).
Subclasses of LDL
Graph-K, LDL-S3GGE™Subclass Distribution.There are seven scientifically known LDL cholesterol subclasses, known as LDL I, IIa, IIb, IIIa, IIIb, IVa, and IVb. The subclasses of IIIa, IIIb, and IVb are made up of smaller, more dense particles (shaded) are more closely related to heart disease
With the use of SGGE, LDL has been divided into seven classes based on particle size. LDL IIIa and IIIb are the most commonly elevated forms of LDL. These particles are small enough to get between the endothelial cells and cause atheromatous disease. LDL IVa and IVb are also very small. These forms of LDL are associated with aggressive arterial plaques that are particularly vulnerable to ulceration and vascular occlusion. Nearly all patients whose LDL IVa and IVb levels are greater than 10% of total LDL will suffer a vascular event within months.14
LDL-S3GGE™Subclass Distribution.There are seven scientifically known LDL cholesterol subclasses, known as LDL I, IIa, IIb, IIIa, IIIb, IVa, and IVb. The subclasses of IIIa, IIIb, and IVb are made up of smaller, more dense particles (shaded) are more closely related to heart disease Graph K
Atherosclerosis:
It is characterized by intimal plaques called atheromas that produce into the lumen, weakened the underline media, and undergo a series of complications.1.
There are four major acquired risk factors that play an important role in process of atherosclerosis.1-Hyperlipidemia 2-Hypertension 3-Cigarette smoking 4-Diabetes.
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