**6. HDL**

HDL is a molecule that is antioxidant, antiinflammatory, antiapoptotic and increases macrophage cholesterol excretion and endothelial healing. The removal of cholesterol from the body by the liver via HDL is called reverse cholesterol transport. ABCA-1, ABCG-1, and SR-B1 are effective in reverse cholesterol transport.

LDL, VLDL, and chylomicron residues can be determined by detecting Apo B levels, there is limited access and standardization for the detection of Apo B level. In the ESC dyslipidemia guide, non-HDL cholesterol calculation is recommended instead of measuring ApoB levels in the presence of hypertriglyceridemia. (Class 2a) In a study conducted by Puri et al., the level of non-HDL cholesterol rather than LDL cholesterol significantly correlated with atheromatous progression when the triglyceride level rises above 200 mg/dl. In the NICE guideline, all individuals are focused on evaluating non-HDL cholesterol exclusively from

Role of Cholesterol as a Risk Factor in Cardiovascular Diseases

http://dx.doi.org/10.5772/intechopen.76357

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Familial hypercholesterolemia is a metabolic disorder that occurs as a result of the absence or lack of LDL receptors in the liver. Since LDL molecules are removed from the circulation, very high LDL levels and premature atherosclerosis are observed. Familial hypercholesterolemia is thought to be approximately 1/500 of the homozygous form and approximately 1/1 million of the heterozygous form. Tendon xanthomas are pathognomonic signs for familial hypercho-

Sitosterol is a plant-derived molecule and its structure resembles cholesterol. Cytosterolemia is a progressive disease with an increase in the absorption and a decrease in biliary secretion of cholesterol and sitosterol molecules. Sitosterolemia is also called pseudohomozygous

• Total cholesterol should be used to predict cardiovascular risk via the SCORE system. (1-C) • LDL-C should be used primarily in screening, diagnosis, risk estimation, and treatment.

• Non-HDL cholesterol should be considered as a risk indicator, especially in individuals

• ApoB should be considered as an alternative risk marker in patients with high triglyceride

• Lp (a) may be considered in individuals with high-risk, early family history of CVD and in

• ApoB1/ApoA1 ratio can be considered as an alternative analysis in risk prediction. (2b-C)

lesterolemia. There is also an increase in the frequency of corneal arcus, xanthelasma.

LDL cholesterol.

**10. Sitosterolemia**

familial hyperlipidemia.

(1-C)

values. (2a-C)

Recommendations for ESC 2016:

with high triglyceride levels. (1-C)

• HDL-C should be used in the Heart Score algorithm. (1-C)

• TG provides additional information in the risk estimation. (1-C)

the reclassification of individuals with borderline risk. (2a-C)

**9. Familial hypercholesterolemia**

ApoA1 and ApoA2 are mainly found in the structure of HDL, and also HDL includes apoCs, ApoE, apoD, apoJ, lecithin-cholesterol acyltransferase (LCAT), serum paraoxonase (PON1) and platelet-activating factor acetylhydrolase (PAF-AH) molecules. Enzymes carried by HDL prevent oxidative modification of LDL.

Pentraxin 3 (PTX-3) in HDL controls leukocyte level. Defective PTX-3 was associated with large atherosclerotic plaques and higher level of inflammation [15, 16].

The association between low HDL and atherosclerotic cardiovascular disease was first shown by the Framingham study. Hypertension, diabetes mellitus, elevated total cholesterol, low HDL cholesterol, smoking, and age is considered as risk factor for coronary artery disease. The association between a low HDL cholesterol and atherosclerosis has been proven, but the increase in HDL has not been associated with a reduction in the incidence of atherosclerotic cardiovascular disease. Due to HDL being a molecule that prevents inflammation, some changes in HDL structure occur in chronic inflammatory processes.
