Lipid Metabolism Overview

Plant sterols and drugs that block cholesterol absorption reduce the re-use of bile cholesterol.

High levels of atherogenic lipoproteins (especially LDL, but also IDL and chylomicron remnants) contribute to the development of atherosclerosis.

Lipoprotein (a) (Lp(a)) is formed when LDL combines with apolipoprotein (a). It carries oxidized phospholipids and is strongly linked to an increased risk of cardiovascular disease.

Oxidized Apo B-containing lipoproteins are not cleared by normal mechanisms.

Endothelium produces Nitric Oxide (NO), which is involved in vasodilation and prevents platelet aggregation. It also produces Prostacyclin, which counteracts Thromboxane and prevents platelet aggregation.

HDL removes cholesterol from tissues and delivers it to the liver for excretion. HDL may also dampen inflammatory responses in blood vessels.

Low HDL levels, often associated with high triglyceride levels, are linked to atherosclerosis.

Excessive intake of carbohydrates, fats, or alcohol can all increase plasma triglyceride levels.

These are cells formed when macrophages engulf LDL cholesterol, contributing to the development of atherosclerosis.

A type of cholesterol that's considered 'good' cholesterol. It helps remove LDL cholesterol from the bloodstream, reducing the risk of heart disease.

A type of cholesterol that's considered 'bad' cholesterol. High levels increase the risk of heart disease.

A blood test that measures the levels of various lipids, including cholesterol and triglycerides, to assess the risk of cardiovascular disease.

A condition characterized by high levels of triglycerides, a type of fat found in the blood.

A measure of the total cholesterol minus HDL cholesterol. It reflects the amount of cholesterol that's potentially harmful.

A protein involved in carrying cholesterol in the blood. It's often used as a marker of cardiovascular disease risk.

It's a formula used to estimate LDL cholesterol levels based on total cholesterol, HDL cholesterol, and triglyceride levels.

The ability of blood vessels to function properly, including their ability to relax and constrict.

A condition characterized by an increased risk of heart disease due to a combination of high triglycerides, low HDL cholesterol, and small, dense LDL cholesterol particles.

Managing cardiovascular disease involves assessing individual risk, treating modifiable factors, and optimizing lifestyle choices like diet and exercise.

Individuals with the highest absolute risk of cardiovascular disease benefit the most from treatment.

Public health guidelines recommend using specific thresholds and algorithms to determine when to start lipid-lowering medication based on individual risk levels.

Individuals with pre-existing cardiovascular disease, diabetes mellitus, chronic kidney problems, inherited high cholesterol, or a 20% or higher risk of cardiovascular disease within the next 10 years are usually considered eligible for medication.

Since age is a strong factor in cardiovascular risk, some guidelines consider a person's lifetime risk when making treatment decisions.

People at high risk should aim for high-density lipoprotein (HDL) levels above 1 mmol/L and fasting triglycerides below 2 mmol/L.

Target levels for low-density lipoprotein (LDL) cholesterol have been lowered to 1.8 mmol/L or less for high-risk patients.

Total cholesterol should generally be below 5 mmol/L during treatment and ideally below 4 mmol/L for high-risk patients and in secondary prevention.

Recent research shows continuous benefit of lowering LDL cholesterol to 1.4 mmol/L, suggesting potential for even lower treatment targets in the future.

Factors like age, blood pressure, lipid profile, smoking history, and personal and family history of cardiovascular disease contribute to overall risk.

Reducing saturated and trans-unsaturated fats to less than 7-10% of total energy intake, limiting cholesterol to under 250mg/day, and replacing unhealthy fats with lean meats, low-fat dairy, and polyunsaturated spreads.

Prioritize vegetables, unrefined carbohydrates, fish, pulses, nuts, legumes, and fruits to improve heart health.

Lifestyle changes can significantly reduce cardiovascular risk. This includes maintaining a healthy weight, increasing physical activity, and avoiding excess alcohol consumption.

Statins are commonly used to lower cholesterol levels by inhibiting the HMG-CoA reductase enzyme. This enzyme is involved in cholesterol synthesis.

Combining different cholesterol-lowering medications can be more effective than using a single drug. For example, statins and ezetimibe can be used together.

Dietary changes are often the first step in lowering cholesterol. However, only modest reductions in LDL-C are usually seen with diet alone.

Even minor weight loss can significantly reduce cardiovascular risk, especially for people with central obesity.

Non-pharmacological management of hyperlipidemia often involves dietary changes, exercise, and weight management. These measures are often effective in lowering cholesterol levels.

Regular physical activité is essential for maintaining cardiovascular health. It helps lower cholesterol levels, improve blood pressure, and increase overall fitness.

Patient adherence to dietary adjustments is crucial for effective cholesterol management. Providing clear explanations, support, and encouragement can significantly improve adherence.

Statins are a class of drugs that reduce the production of cholesterol in the liver, leading to an overall decrease in LDL cholesterol levels.

Statins primarily work by inhibiting the enzyme HMG-CoA reductase, which is crucial for cholesterol biosynthesis.

Secondary effects of statins include an increase in the number of LDL receptors in the liver, enhancing LDL clearance and further reducing LDL synthesis.

Statins can decrease LDL cholesterol by up to 60%, triglycerides by up to 40%, and increase HDL cholesterol by up to 10%.

Common side effects of statins include muscle pain (myalgia), elevated creatine kinase levels, and in rare cases, rhabdomyolysis.

Ezetimibe acts by blocking the absorption of cholesterol from the intestine, both dietary and biliary.

By reducing cholesterol absorption, ezetimibe indirectly leads to an increase in LDL receptor production in the liver, similar to the effects of statins.