Steps of formation of atherosclerosis

 

The summary of atherosclerosis stages is accurate and aligns with current medical understanding. Here's a breakdown of the key stages with supporting details:

1. Endothelial Dysfunction & Fatty Streaks

• Endothelial damage: Triggered by hypertension, smoking, or high LDL cholesterol, leading to inflammation and oxidative stress
• Lipid accumulation: Oxidized LDL particles infiltrate the damaged endothelium, attracting monocytes that differentiate into macrophages. These engulf lipids, forming foam cells (visible as fatty streaks)
• Early lesions: Fatty streaks appear as yellow patches in arteries, often detectable by adolescence

2. Plaque Progression (Fibrous Plaque)

• Smooth muscle cell (SMC) migration: SMCs from the tunica media migrate to the intima, proliferate, and secrete collagen, forming a fibrous cap
• Plaque growth: Continued lipid deposition, macrophage infiltration, and release of matrix metalloproteinases (MMPs) weaken the cap
• Chronic inflammation: T-cells and macrophages secrete cytokines (e.g., TNF-α, IL-1) that sustain inflammation and inhibit collagen synthesis

3. Plaque Rupture & Complications

• Vulnerable plaques: Thin fibrous caps with large lipid cores are prone to rupture due to MMP activity
• Thrombosis: Rupture exposes thrombogenic material (e.g., collagen), triggering clot formation that may occlude arteries
• Clinical outcomes:
• Stenosis: Chronic narrowing reduces blood flow, causing ischemia (e.g., angina)
• Acute occlusion: Sudden clot formation leads to myocardial infarction or stroke

Additional Notes

• Calcification: Advanced plaques often calcify, increasing rigidity and rupture risk
• Asymptomatic progression: Atherosclerosis develops silently over decades, with symptoms typically manifesting after age 65