THE PRINCIPAL CHOLESTEROL DISORDERS

THE PRINCIPAL CHOLESTEROL DISORDERS


Cholesterol is a fat-like substance (lipid) that is present in cell membranes and is a precursor of bile acids and steroid hormones. Cholesterol travels in the blood in distinct particles containing both lipid and proteins (lipoproteins). Three major classes of lipoproteins are found in the serum of a fasting individual: low density lipoproteins (LDL), high density lipoproteins (HDL), and very low density lipoproteins (VLDL). Another lipoprotein class, intermediate density lipoprotein (IDL), resides between VLDL and LDL; in clinical practice, IDL is included in the LDL measurement.

Each class contains differing proportions of fat and protein. VLDL consist of five-sixths triglycerides and one-sixths cholesterol. While circulating in the blood, VLDL is transformed first to intermediate-density lipoprotein (IDL), which is 30% cholesterol and 40% triglycerides, and then to low-density lipoprotein (LDL), which carries from 60% to 75% of the total blood cholesterol. High levels of LDL-cholesterol are associated statistically with an increased risk of coronary heart disease (CHD) – the higher the level, the higher the risk.

HDL carries less than 25% of the total blood cholesterol. It is thought to assist with the removal of LDL-cholesterol from the blood and body tissues. High levels of HDL-cholesterol appear to be protective against coronary heart disease – the higher the LDL level, the lower the risk.

The principal cholesterol disorders are classified into 5 mayor types according to the nature of the lipoprotein abnormality and associated clinical features. Type I and V are not associated with the development of atherosclerosis. Type II, III and IV are associated with the atherosclerotic process that causes coronary heart disease and peripheral vascular disorders. The lipoprotein features of these classes are as follows :
Type IIa: increased total cholesterol and LDL-cholesterol; normal triglycerides.
Type IIb: increased total cholesterol, LDL-cholesterol and VLDL; moderately increased triglycerides.
Type III: increased IDL-cholesterol (abnormal form); increased triglycerides.
Type IV: normal total cholesterol, increased VLDL, decreased HDL-cholesterol; increased triglycerides.

See also on the classification of lipoprotein abnormality according to Frederickson-WHO in the table below.


Cholesterol Management Program
Peoples who might benefit from evaluation at the Center include :

1. Diabetics with low HDL (“good”) cholesterol and high triglycerides
2. Any people with total cholesterol > 220 AND triglycerides > 200
3. Markedly elevated LDL (“bad”) cholesterol > 200
4. Isolated low HDL cholesterol (normal total cholesterol and triglycerides)
5. Strong family history of early heart disease (males < 55 years old, females < 65 years old)
6. Need for combination therapy (2 or more cholesterol drugs)
7. Peoples with prior heart attack, stroke, or revascularization procedure (bypass or angioplasty) who are having evidence of disease progression despite treatment
8. Intolerant of cholesterol drugs, especially “statins” like Lipitor, Crestor, Zocor, Pravachol, Lescol, Mevacor, and Vytorin

It is also important to lose weight if you are overweight, to be physically active, and to not smoke. Discuss your treatment plan with your doctor.


Reference :

1. NCEP; Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) – Final Report, NIH Publication No. 02.5215, September 2002
2. Long JW, The Essential Guide to Prescription Drugs, HarpersCollins Publisher, Inc. 1993 Edition, 50-52
3. Wormser H (PhD,Professor of Medical Chemistry), Lipoprotein Metabolism. Power Point Presentation, PSC 3110 Fall 2004
4. http://www.heartoflouisiana.com/programs.php