Dyslipidemia

Cardiovascular disease (CVD) is the leading cause of death in both men and women. On average, more than 2,200 Americans lose their lives to cardiovascular disease each day. Most patients had at least one established CV risk factor – hypertension, dyslipidemia and/or diabetes.

The term dyslipidemia refers to a disturbance of the lipid profile, including both hyperlipidemia and hypolipidemia. Dyslipidemia, the hallmark of the metabolic syndrome, includes increased flux of free fatty acids, raised triglycerides, apolipoprotein B, and small dense low-density lipoprotein, and decreased high density lipoprotein cholesterol.

Dyslipidemia has been well established as an independent risk factor for cardiovascular disease. It refers to the following lipid levels:
*Total cholesterol (TC) > 5.2 mmol/L
*High density lipoprotein cholesterol (HDL-C) < 1.0 mmol/L (males) < 1.2 mmol/L (females)
*Triglycerides (TG) > 1.7 mmol/L
*Low density lipoprotein cholesterol (LDL-C) levels

Low HDL cholesterol and hypertriglyceridemia have been found to be independently and significantly related to myocardial infarction/stroke in patients with metabolic syndrome.

Classification of dyslipidemia
*Primary – due to genetic
*Secondary
Dyslipidemia

Chylomicron: Triglyceride-rich lipoproteins

Chylomicrons are large, triglyceride-rich lipoproteins that are produced in intestinal enterocytes in response to fat ingestion, which function to transport the ingested lipids to different tissues. From the Greek names ‘chylo’ meaning juice or milky fluid and micron meaning small particle.

The chylomicron may be thought of as a particle that has as its main function the transport of fat from the intestinal lumen to the liver. On the way to uptake by the liver, the chylomicron divests itself of lipid to the adipocyte for storage or the muscle and other cells for energy.

Their triglycerides are partially hydrolyzed during circulation as a result of the action of endothelial cell-bound lipoprotein lipase. The removal of triglycerides from chylomicrons in the peripheral tissues results in the formation of chylomicron remnants. The remnants are smaller particles that are mainly composed of cholesterol and are cleared primarily by the liver through a process mediated by apolipoprotein E and modulated by apolipoprotein C and phospholipids. The remnants are also linked to cardiovascular disease.

These particles consist of triglycerides (main constituent), phospholipids, cholesterol, proteins, apolipoproteins and fat-soluble vitamins. Apolipoproteins are the key protein constituents of chylomicrons. Although these proteins generally represent only less than 2% of the chylomicrons' total mass, they determine the intra- and extra-cellular metabolic fate of these lipoproteins.

Chylomicron major lipid is triglycerides, which comprise more than 75% of the particle, and they have the lowest protein content of all lipoproteins of around 2 percent.
Chylomicron: Triglyceride-rich lipoproteins