HLD

Hyperlipidemia

A disorder of lipid metabolism characterized by an increase in triacylglycerol (TG), total cholesterol (Chol), low-density lipoprotein (LDL), a decrease in high-density lipoprotein (HDL) in the peripheral blood, and is a risk factor for atherosclerosis leading to strokes, coronary artery disease, and myocardial infarction.

Hypercholesterolemia

A type of hyperlipidemia that focuses on high low-density lipoprotein cholesterol (LDL-C).

Lipoproteins

Vehicles of Dietary (Chylomicron) & Endogenously Synthesized Lipids (VLDL) and Specific Apolipoproteins (e.g., apoB100, apoC-II) of Physiological Significance in Blood Circulation.

Chylomicron

Transporting dietary TGs from the intestine to the adipose tissue.

VLDL

Transporting endogenously synthesized TG from the liver to the adipose tissue.

LDL

Contains exclusively apoB100 indicating VLDL is the principal precursor of LDL.

Oxidatively modified LDL (oxLDL)

Uptake and accumulation by scavenger receptors in macrophages initiates a wide range of bioactivities that may drive development of atherosclerotic lesions.

Reverse cholesterol transport

The pathway mediated by HDL which transports excess cholesterol away from peripheral tissues to the liver.

HDL

Known as the 'good' cholesterol, confers protection against atherosclerosis.

Apolipoproteins

Key protein structural components of lipoproteins that delineate their specific functions.

Nascent HDL

Synthesized in liver and intestinal cells, exchanges proteins with chylomicrons and VLDL.

Cholesterol ester (CE)

Formed from cholesterol by the LCAT reaction when HDL picks up cholesterol from cell membranes.

Cholesterol Ester Transfer Protein (CETP)

Mediates the exchange of cholesterol esters between HDL and VLDL.

ABCA1

ATP-binding cassette protein involved in the reverse transport of cholesterol from the inner leaflet of cell membrane to the outer leaflet.

Hepatic TG lipase (HTGL)

Has phospholipase activity, hydrolyzes phospholipid and TGs in HDL2, allowing the release of CE cargo to the liver.

Hypolipoproteinemia

Condition characterized by low levels of lipoproteins.

Atherosclerotic plaque

Develops as a result of the accumulation of oxidized LDL and other factors in the arterial walls.

Statins

Medications that lower LDL-cholesterol and reduce the risk for atherosclerosis.

Lipid metabolism

The process by which lipids are synthesized and degraded in the body.

Myocardial infarction

A medical term for a heart attack, often associated with atherosclerosis.

Coronary artery disease

A condition caused by the buildup of plaque in the coronary arteries, leading to reduced blood flow to the heart.

Hypertension

High blood pressure, often associated with hyperlipidemia.

Diabetes

A major vascular risk factor associated with hyperlipidemia.

Obesity

A condition that is a major vascular risk factor associated with hyperlipidemia.

LDL receptors

Specific membrane receptors that mediate the uptake of LDL in normal individuals.

Lipid solubilization

The process by which lipoproteins facilitate the delivery of lipids in blood plasma to specific tissues.

Lecithin Cholesterol Acyl Transferase (LCAT)

An enzyme that converts phospholipid and cholesterol into nonpolar cholesterol esters.

Tangier's Disease

Genetic disorder causing defective ABC1 transporter.

ABC1 Transporter

Protein responsible for cholesterol transport in cells.

HDL Levels

Decreased HDL levels lead to cholesterol accumulation.

Cholesterol Esterification

Conversion of cholesterol to cholesterol ester by LCAT.

LCAT Deficiency

Inability to esterify cholesterol, raising unesterified levels.

Scavenger Receptor SR-B1

Facilitates cholesterol delivery to steroidogenic tissues.

Oxidized LDL

Damages endothelial cells, promoting atherosclerosis.

Familial Hypercholesterolemia (FH)

Genetic disorder with defective LDL receptors.

LDL-Receptor Deficiency

Increases LDL residence time in blood plasma.

Xanthomas

Visible lipid deposits in skin and tendons.

Arcus Corneal

Cholesterol deposit forming arc in cornea.

Tendinous Xanthomas

Lipid deposits around tendons and ligaments.

Bile Acid Resins

Drugs that increase fecal bile acid excretion.

Gemfibrozil

Fibrate that increases risk of myopathy with statins.

Foam Cells

Macrophages filled with oxidized LDL, forming fatty streaks.

Atherosclerotic Plaque

Formed from fatty streaks, occludes blood vessels.

Ischemia

Reduced blood flow leading to tissue damage.

Myocardial Infarction

Heart attack due to blocked coronary arteries.

Cytokines

Signaling molecules that influence macrophage behavior.

Cholesterol Levels in FH

Heterozygous: 320-500 mg/dL; Homozygous: 600-1200 mg/dL.

Unesterified Cholesterol

Cholesterol not converted to cholesterol esters.

Endothelial Cells

Cells lining blood vessels, affected by oxidized LDL.

Phosphatidylcholine (PC)

Lecithin that participates in LCAT reaction.

Cholesterol Pool

Total cholesterol available for metabolic processes.

Feedback Inhibition

High cholesterol levels inhibit HMG-CoA reductase.

LDL Cholesterol

Low-density lipoprotein associated with cardiovascular risk.

Peripheral Neuropathy

Nerve damage causing weakness or pain in limbs.