Lipoprotein Metabolism Overview

The process of transporting lipids (fats) through the bloodstream using specialized complexes called lipoproteins.

Complexes of proteins and lipids that transport lipids through the bloodstream.

Large lipoprotein particles carrying dietary fats from the intestines to the body's tissues.

An enzyme that breaks down triglycerides in lipoproteins, releasing fatty acids for use by cells.

A type of lipoprotein that helps remove cholesterol from the body.

A type of lipoprotein that carries cholesterol to the cells; high levels can be harmful.

Proteins associated with lipoproteins that aid in their function and regulation.

The process of absorbing dietary fat, processing it into chylomicrons, and transporting it in the bloodstream.

HDL transports cholesterol from non-liver cells to the liver for removal from the body.

HDL starts as a small particle (nascent HDL) containing phospholipids, cholesterol, and apolipoproteins. It matures into a spherical shape as it picks up and converts cholesterol.

Dyslipidemias, or abnormal serum lipid levels, often arise from genetic issues, lifestyle choices, or secondary health conditions affecting lipoprotein function.

A genetic defect in LDL receptors leads to a lack of LDL uptake by cells, causing increased cholesterol in the blood.

High LDL cholesterol levels due to the defective receptor cause elevated total blood cholesterol and high risk of heart attack.

Conditions involving excessive lipoprotein levels, encompassing hypercholesterolemia, hypertriglyceridemia, mixed hyperlipidemia, and abnormal lipoprotein(a).

Elevated cholesterol in the blood can be a primary genetic disorder or secondary to another illness.

A rare, severe form of primary hypercholesterolemia characterized by almost no functional LDL receptors and very high levels of LDL cholesterol, leading to premature heart attacks.

A genetic disorder causing very high cholesterol levels (800-1000 mg/dL) due to defective LDL receptor function.

A genetic disorder causing moderately high cholesterol levels (300-600 mg/dL) due to reduced LDL receptor function, increasing risk of heart disease.

High cholesterol caused by another underlying medical condition, not a genetic defect (e.g., hypothyroidism, diabetes).

High levels of triglycerides in the blood, often exceeding 200 mg/dL, usually secondary to another condition.

Inherited condition causing high triglycerides due to overproduction by the liver.

Inherited condition where the body cannot break down fats effectively, leading to high triglycerides and chylomicrons.

Plasma triglycerides above 200 mg/dL (2.3 mmol/L), potentially indicating a problem with lipoprotein metabolism (e.g., high VLDL or chylomicrons).

High triglycerides caused by another problem, not a genetic defect, often involve other health issues or medications.

Lp(a) might compete with plasminogen for fibrin binding, potentially promoting blood clotting.

A condition with very low HDL cholesterol, often due to genetic issues.

Severe form of hypoalphalipoproteinemia, with exceptionally low HDL levels.

Impaired chylomicron and LDL synthesis; leads to lipid transport problems.

Lack of LCAT enzyme = free cholesterol buildup in tissues, linked to health issues.

Temporary decrease in HDL cholesterol due to events like infections or surgery; temporary.

A crucial measure of heart health associated with HDL-C levels below 40 mg/dL.

Esterification of cholesterol, a key chemical process in cell function.

A condition where the body lacks or has reduced lipoprotein lipase enzyme activity, leading to high triglycerides in the blood, often presenting in childhood or adulthood, depending on subtype.

High triglyceride levels caused by factors other than a genetic defect, such as obesity, diabetes, or certain medications.

High levels of both cholesterol and triglycerides in the blood.

A genetic disorder causing high levels of both cholesterol and triglycerides, often due to increased liver production of certain proteins.

A genetic disorder where specific lipid particles (IDL and chylomicron remnants) accumulate due to apolipoprotein E abnormalities, resulting in mixed hyperlipidemia.

High levels of lipoprotein(a) in the blood, a type of LDL-like particle that increases the risk of heart disease and stroke.

A specific genetic variant of the Apo E protein, leading to increased cholesterol and triglyceride levels, a cause of Familial dysbetalipoproteinemia

High cholesterol and triglyceride levels resulting from underlying conditions like poorly controlled diabetes or hypothyroidism.

High total and LDL cholesterol are linked to a higher chance of ischemic heart disease, while high HDL cholesterol is linked to a lower risk.

LDL cholesterol, carrying apoB, gets stuck in artery walls, triggering inflammation.

Macrophages engulf LDL in artery walls, forming foam cells, a key step in atherosclerosis.

Smooth muscle cells create a barrier to limit plaque spreading, but inflammation can destabilize it.

Uncontrolled inflammation damages the plaque's protective layer, leading to cell death and a weaker, more prone-to-rupture plaque.

HDL helps reduce inflammation and remove cholesterol, reducing plaque formation and cardiovascular risks.

Reducing LDL cholesterol levels helps lower the risk of cardiovascular disease.

High cholesterol, smoking, and high blood pressure are major risk factors, along with other important factors.