Atherosclerosis Quiz

Atherosclerosis

• A chronic inflammatory disease caused by lipid-laden macrophages accumulating in artery walls, forming plaques.
• Initiated by endothelial injury, due to factors like hypertension, dyslipidemia, smoking, and diabetes.
• Oxidized LDL plays a vital role in macrophage uptake, forming foam cells, and contributing to fatty streaks (the earliest atherosclerotic lesion).

Pathophysiology of Atherosclerosis

• Endothelial Dysfunction: Injury to the endothelium (inner lining of blood vessels) from risk factors like hypertension, smoking & diabetes causes inflammation and impaired production of protective factors like nitric oxide. Adhesion molecules increase on the injured surface to attract immune cells (like monocytes/T-lymphocytes).
• Fatty Streak Formation: Oxidized LDL penetrates the injured endothelium and gets engulfed by macrophages, forming foam cells. These clustered foam cells form the first visible atherosclerotic lesions.
• Fibrous Plaque Formation: Smooth muscle cells migrate to the tunica intima (inner layer of the vessel wall) and proliferate. They secrete extracellular matrix components (like collagen & elastin), forming a fibrous cap over the lipid core, stabilizing the plaque, but maintaining the risk of rupture.
• Complicated Plaque (Rupture) and Thrombus Formation: Exposure of the thrombogenic lipid core and extracellular matrix proteins to the bloodstream activates platelets, leads to platelet plug formation, and eventually a thrombus (blood clot). Thrombus can be large enough to occlude blood flow, causing ischemia or infarction.

Disease Transmission

• Atherosclerosis is not contagious.
• Environmental exposure to risk factors (like secondhand smoke) can indirectly influence development.
• Some evidence suggests a role for certain infections (e.g., Chlamydia pneumoniae) in chronic vascular inflammation, but this is controversial.

Risk Factors for Atherosclerosis

• Non-modifiable: Age, sex, ethnicity, family history.
  • Risk increases with age, men generally have a higher risk, and post-menopausal women experience increased risk due to estrogen loss. Specific ethnic groups and those with a family history of early-onset cardiovascular disease are at higher risk.
• Modifiable:
  • Dyslipidemia: High LDL and low HDL cholesterol are key drivers.
  • Hypertension: Damages endothelium and promotes plaque formation.
  • Smoking: Oxidizes LDL, damages endothelium, and increases blood clotting.
  • Diabetes: Chronic hyperglycemia damages the endothelium and promotes inflammation.
  • Obesity/Increased waist circumference: Associated with metabolic syndrome (insulin resistance, hypertension, and dyslipidemia).
  • Sedentary lifestyle: Contributes to metabolic syndrome and obesity.
  • Diet: Diets high in saturated and trans fats, and simple sugars increase risk.
  • Additional Factors: Inflammation markers (e.g., CRP), microbiome changes (e.g., TMAO production) also contribute to atherosclerosis development.

This quiz explores the mechanisms behind atherosclerosis, a chronic inflammatory disease affecting arteries. It delves into endothelial dysfunction, the role of oxidized LDL, and the formation of fatty streaks. Test your understanding of the disease's progression and contributing risk factors.