Heart Medications and Cholesterol Management

Heart Medications Overview

• Focus on heart medications, particularly concerning cholesterol and its role in heart disease.

Arteriosclerosis and Cholesterol

• Nitric oxide as a signaling molecule, discovered by Robert F. Furchgott, Louis J. Ignarro, and Ferid Murad (1998 Nobel Prize).
• Arterial blockages often involve cholesterol, which is present in all animal cells.
• High blood cholesterol is strongly associated with heart attacks.

Types of Cholesterol

• Cholesterol vs. Cholesterols:
  • Cholesterol exists as a metabolic intermediate, from which bile acids and steroid hormones are synthesized.
  • It plays roles in signaling, development, and differentiation (e.g., Hedgehog signaling).

Dietary Sources of Cholesterol

• Small contribution from diet, primarily from animal-sourced foods:
  • Meats (beef, pork, lamb)
  • Poultry (chicken, turkey)
  • Eggs (especially yolks)
  • Seafood (shrimp, crab, fish)
  • Dairy (milk, cheese, butter)
• Examples of cholesterol content in foods:
  • Egg yolk: 300 mg
  • Shrimp: 181 mg
  • Crab: 113 mg

Cardiovascular Implications of Cholesterol

• LDL (Low-Density Lipoprotein):

  • Known as "bad cholesterol."
  • Excess LDL can lead to plaque buildup in arteries, reducing blood flow and increasing heart disease risk.

• HDL (High-Density Lipoprotein):

  • Known as "good cholesterol."
  • Transports excess cholesterol from bloodstream back to the liver for disposal.
  • High levels of HDL are beneficial.

Role of Statins in Cholesterol Management

• Statins:
  • Class of drugs that inhibit cholesterol biosynthesis by blocking HMG-CoA reductase, leading to lower cholesterol levels.
  • Initial statin (Lovastatin) discovered by Akira Endo.
  • Lipitor (Atorvastatin) became the most prescribed drug, showing significant efficacy in lowering LDL.

Biological Mechanisms of Cholesterol Synthesis

• Cholesterol synthesized mainly in the liver:
  • From saturated fats via a series of chemical reactions involving HMG-CoA.
• Excess cholesterol can accumulate in arterial walls due to elevated LDL levels leading to cardiovascular issues.

Inflammatory Processes and Heart Disease

• Inflammation can lead to plaque rupture in arteries, resulting in clot formation and potential heart attacks.
• C-reactive protein serves as a marker for increased heart disease risk, produced during inflammation.

Lipoproteins and Cholesterol Transport

• Body uses lipoproteins (composed of triglycerides and cholesterol) to transport cholesterol:
  • LDL deposits cholesterol at body tissues while HDL scavenges excess cholesterol back to the liver.

Recommended Blood Cholesterol Levels

• Total Cholesterol Levels (mmol/L):

  • Normal: <5.2
  • Borderline: 5.2 - 6.2
  • High: >6.2

• LDL Levels (mmol/L):

  • Normal: <3.4
  • Borderline: 3.4 - 4.1
  • High: >4.1

• HDL Levels (mmol/L):

  • Not good: <1.0
  • Good: >1.56

Effects of Fatty Acids on Cholesterol

• Dietary fats:

  • Saturated and trans fats raise LDL cholesterol levels, increasing heart disease risk.
  • Unsaturated fats can help lower LDL.

• Partial hydrogenation in food processing creates trans fats, which significantly alter cholesterol profiles negatively.

Public Health Measures

• Canada has banned trans fats to reduce heart disease risk, signaling a shift towards healthier dietary practices.