Physiological Adaptation Q 174
The following are lipid abnormalities. Which of the following is a risk factor for the development of atherosclerosis and PVD?
A. High levels of low-density lipid (LDL) cholesterol
B. High levels of high-density lipid (HDL) cholesterol
C. Low concentration triglycerides
D. Low levels of LDL cholesterol.
Correct Answer: A. High levels of low-density lipid (LDL) cholesterol
An increase in LDL cholesterol concentration has been documented as a risk factor for the development of atherosclerosis. LDL cholesterol is not broken down into the liver but is deposited into the wall of the blood vessels. As the LDL particles leave the blood and enter the arterial intima, they accumulate by being trapped by proteoglycans and are modified. While the modifications of LDL are not elucidated, oxidative modification generating oxidized LDL appears to be an attractive candidate.
Option B: High-density lipids are called the “good” cholesterol. They absorb cholesterol and carry it back to the liver. The liver then flushes it from the body. HDL is known for its anti-atherogenic and anti-inflammatory properties, thanks to its uptake and return of the cholesterol stored in the foam cells of atherosclerotic plaques to the liver. Thus, reducing the size of the plaque and its associated inflammation.
Option C: Triglycerides are the type of fat found in the blood. When we eat, the body converts any calories it doesn’t need to use right away into triglycerides. These are stored into fat cells. Later, hormones release triglycerides for energy between meals.
Option D: Low levels of LDL or the “bad” cholesterol reduces the risk for atherosclerosis and PVD. Modified LDL is taken up by scavenger receptors (SR) such as SRA and CD36 resulting in foam cell formation since cellular cholesterol content does not regulate these SRs. Following endothelial dysfunction induced by LDL, smoking, diabetes, hypertension, among others, there is a deficiency of NO and prostacyclin and/or an increase in plasminogen activator inhibitor type 1 (PAI-1) and cell adhesion molecules (CAMs).