Endothelial And Blood Lipid Optimization Part 3: Blood Lipids

This article is part 3 of a 3 part series.

In part 1 of this series, an overview of the gravity of atherosclerotic cardiovascular disease and the fundamentals of plaque formation were reviewed. In part 2, the crucial role of endothelial function was presented. This article provides an overview of blood lipids and their role in atherosclerotic cardiovascular disease. 

Atherogenic Blood Lipids and Atherosclerosis

An atherogenic lipid profile, also known as dyslipidemia, increases the risk of atherosclerotic cardiovascular disease. In particular, apolipoprotein B (apoB)-containing lipoproteins have been shown to associate with atherosclerosis (15). Oxidized low-density lipoproteins (ox-LDLs) also contribute to the progression of atherosclerosis whereas high-density lipoproteins (HDL) contribute to the removal of cholesterol from macrophages thereby inhibiting the formation of foam cells (16). It is important to know what a lipoprotein is as the impression is often that they are cholesterol itself whereas they are actually the transport mechanism for cholesterol.  

From Wikipedia:

A lipoprotein is a biochemical assembly whose primary function is to transport hydrophobic lipid (also known as fat) molecules in water, as in blood plasma or other extracellular fluids. They consist of a triglyceride and cholesterol center, surrounded by a phospholipid outer shell, with the hydrophilic portions oriented outward toward the surrounding water and lipophilic portions oriented inward toward the lipid center.

High density lipoparticles (HDL) carry cholesterol out of circulation and low density lipoparticles (LDL) move cholesterol into circulation. This is why HDL is often referred to as ‘good cholesterol’ and LDL as ‘bad’ cholesterol. 

The nomenclature of ‘good’ and ‘bad’ cholesterol is understandable though largely misleading as cholesterol is an essential component in physiological function and performs actions such as making hormones and building cell membranes. It is also important to note that cholesterol is made and utilized by cells throughout the body to maintain their function and structure so accessing it from the bloodstream is largely unnecessary. Teenagers tend to naturally have lower blood levels of cholesterol even though they are in prime years for growth and hormone production and don’t suffer consequences for these low levels. 

For quantifying the amount of cholesterol in the body that is atherogenic, apolipoprotein B (apoB) is an incredible tool. 

Apolipoprotein B (ApoB): Quantifying Atherogenic Particles 

Apolipoprotein B is the primary apolipoprotein of chylomicrons, VLDL, Lp(a), IDL, and LDL particles. These are considered primary atherosclerotic compounds and apoB is the primary organizing protein and required for the production of them. 

LDL has been reviewed previously, and below is a brief description of the other compounds:

• Chylomicrons: ultra low-density lipoproteins (ULDL) that are lipoprotein particles consisting of triglycerides (85–92%), phospholipids (6–12%), cholesterol (1–3%), and proteins (1–2%)
• VLDL: very low density lipoprotein
• Lp(a): a low-density lipoprotein containing a protein called apolipoprotein(a)
• IDL: intermediate density lipoprotein

Although it can still be helpful to receive traditional lipid profile testing, ApoB provides excellent insight into the family of atherogenic lipoproteins and is the test most highly recommended for this purpose. Fortunately, apoB is a simple test and available through major labs such as labcorp and Quest. It is often covered by insurance. 

Symptoms of elevated blood lipids

Unfortunately, the most frequent symptom of elevated blood lipids is an emergency: a heart attack or stroke. The gradual build up of atherogenic plaques takes place over decades, and, ironically, even though it is the number one killer in the United States, is often without symptoms, particularly in the early stages. 

There can sometimes be symptoms before a serious cardiovascular event such as heart attack or stroke occurs, particularly in the latter stages of ASCVD and these may include: 

• Chest pain (angina) 
• Cold sweats
• Dizziness
• Extreme tiredness and weakness
• Heart palpitations
• Shortness of breath
• Nausea
• Cognitive problems
• Erectile dysfunction

There are symptoms that may indicate an emergency situation due to ASCVD, such as a heart attack or stroke.

Heart attack symptoms may include (CDC):

• Chest pain or discomfort. Most heart attacks involve discomfort in the center or left side of the chest that lasts for more than a few minutes or that goes away and comes back. The discomfort can feel like uncomfortable pressure, squeezing, fullness, or pain
• Feeling weak, light-headed, or faint. You may also break out into a cold sweat.
• Pain or discomfort in the jaw, neck, or back
• Pain or discomfort in one or both arms or shoulders
• Shortness of breath. This often comes along with chest discomfort, but shortness of breath also can happen before chest discomfort.

Stroke symptoms may include (CDC):

• Sudden numbness or weakness in the face, arm, or leg, especially on one side of the body
• Sudden confusion, trouble speaking, or difficulty understanding speech
• Sudden trouble seeing in one or both eyes
• Sudden trouble walking, dizziness, loss of balance, or lack of coordination
• Sudden severe headache with no known cause

Causes of an unhealthy lipid profile

An unhealthy lipid profile may be caused by:

• Excess saturated fat intake
• Obesity
• Lack of exercise
• Smoking
• Excess alcohol intake
• Certain medications
• Older age
• Genetics

Preventing and reversing elevated lipid levels

Fortunately, there are a range of tools to prevent and reverse elevated levels of atherosclerotic lipids and the subsequent formation of ASCVD. These include:

• Monitoring blood lipid levels (as shown below)
• A diet lower in saturated fat and higher in monounsaturated and polyunsaturated fats
• Staying physically active to maintain optimal body composition
• Moderating alcohol consumption
• Quitting smoking if a smoker
• Various pharmacological interventions are available if needed

If atherosclerotic plaques have developed, treatment is generally similar to prevention, though more aggressive pharmacological interventions may be needed to slow or halt the progression. Another innovative therapy for managing atherosclerosis is high-dose IV phosphatidylcholine.