Very Low-Density Lipoprotein (VLDL)

What sample is needed for Very Low-Density Lipoprotein (VLDL)?

1. The best sample is serum after 10 to 12 hours of fasting.
2. Plasma can also be used.
3. The preservative is stable for one week at 4 °C.

What are the Indications for Very Low-Density Lipoprotein (VLDL)?

1. These are estimated to predict heart disease.
2. Lipoprotein may be part of the lipid profile.
3. These are done regularly to monitor the disease.

What are the precautions for Very Low-Density Lipoprotein (VLDL)?

1. Keep in mind that smoking and alcohol decrease HDL values.
2. After myocardial infarction, the cholesterol level may be decreased.
3. HDL values are age and sex depending.
4. Drugs that may affect (increase) the lipoproteins are Aspirin, Phenothiazines, Sulfonamides, oral contraceptives, and steroids.
5. HDL is raised in Hypothyroidism and decreased in Hypothyroidism.

What are lipoproteins?

1. Lipoproteins consist of the following:
   1. High-density lipoprotein (HDL).
   2. Low-density lipoprotein (LDL).
   3. Very low-density lipoprotein (VLDL).
   4. Chylomicrons
2. The outer covering lipoproteins are called Apoproteins, and these are classified into:
   1. Apo-1.
   2. Apo-II.
   3. Apo- B.
   4. Apo-D.
   5. Apo-E.

1. Apolipoproteins are a hydrophilic component of lipoproteins.
   1. Lipids like cholesterol and triglycerides are hydrophobic and need to be placed in water-soluble micellar structures (Apolipoproteins) to be transported in the plasma.
   2. Apo-C, B-100, and E become the main components.

Very low-density lipoprotein (VLDL)

1. It originates from the liver and carries triglycerides from the liver to other tissues.
2. VLDL carries a minimal amount of cholesterol.
3. It is the product of endogenous lipoprotein synthesis in the liver and is delivered to the tissue.
   1. VLDL proteins are the primary carrier of triglycerides synthesized in the liver.
   2. Triglycerides are derived from dietary precursors, such as free fatty acids, glycerol, and carbohydrates. 
      1. Triglycerides are a predominant component.
   3. VLDL contains about 10% cholesterol and functionally important apolipoproteins.
   4. VLDL may be expressed as the percentage of cholesterol.
   5. The Apo-C activates the release of lipoprotein lipase enzyme, which hydrolyzes triglyceride into glycerol, monoglycerol, and free fatty acids.
      1. This reaction may give rise to intermediate lipoproteins (IDL).
4. VLDL consists of the following:
   1. Triglycerides = 40% to 60%
   2. Cholesterol = 5% to 8%
   3. Cholesterol ester = 11% to 14%
   4. Phospholipids = 20% to 23%
   5. Protein = 4% to 11%

1. 1. Another source:
   2. Triglycerides = 60%
   3. Cholesterol = 15%
   4. Phospholipids = 15%
   5. Protein  10%

What is the composition of the Very Low-Density Lipoprotein (VLDL)?

• It is a pre-β-lipoprotein derived from the liver.

What is the difference between VLDL and LDL?

1. LDL has lower triglyceride and higher cholesterol content.
   1. LDL carries 70% of the total cholesterol and very little triglyceride.
2. LDL has no apoproteins C or E.
3. Inside the cells, the LDL molecule is metabolized into its parts.
4. It shows that LDL has a major role in providing cholesterol to the body cells and leads to atherosclerosis.
5. VLDL has the majority of triglycerides and less cholesterol content.

What are the drawbacks of Very Low-Density Lipoprotein (VLDL)?

1. VLDL is associated with an increased risk of coronary heart disease.
2. VLDL can convert to LDL.
3. More than 25% to 50% of Very Low-Density Lipoprotein (VLDL) is associated with increased coronary heart disease.

What are the functions of Very Low-Density Lipoprotein (VLDL)?

1. Very Low-Density Lipoprotein (VLDL) has the main role of transporting endogenously synthesized triglycerides by the liver to:
   1. Adipose tissue.
   2. Muscles.
2. Very Low-Density Lipoprotein (VLDL) carries triglycerides from the intestinal mucosa to the periphery.
3. Very Low-Density Lipoprotein (VLDL) is mainly synthesized in the liver and, to a lesser extent, the intestinal tissues.
4. Very Low-Density Lipoprotein (VLDL) passes through a transient intermediate lipoprotein form called intermediate-density lipoprotein (IDL).
5. Intermediate-density lipoprotein (IDL) changes to Low-density lipoprotein (LDL).

What is the normal value of Very Low-Density Lipoprotein (VLDL)?

Source 2

• 7 to 32 mg/dL.

Another source

• 25% to 50%

Source 4

What are the causes of increased Very Low-Density Lipoprotein (VLDL)?

1. Nephrotic syndrome.
2. Glycogen storage diseases.
3. Familial LDL lipoproteinemia.
4. Hypothyroidism.
5. Chronic liver disease.
6. Liver cell carcinoma.
7. Gammopathies.
8. Cushing syndrome.
9. Familial hypercholesterolemia.

What are the causes of decreased Very Low-Density Lipoprotein (VLDL)?

1. Hypoproteinemia.
2. Hyperthyroidism.
3. Familial hypolipoproteinemia.

How will you summarize the characteristics of the lipoproteins?

Note: Lipoproteins are described in detail in LDL and HDL.

Questions and answers: