Apo B100 : the Bees Knees

If you have delved into longevity medicine and/or lipidology recently you will have come across the blood marker Apo B 100. This is a protein present on every atherogenic particle that crosses the blood vessel lining which has the potential to turn into the plaques that cause heart attacks and strokes. (Note that Apo B, Apo B 100, and Apolipoprotein B 100 are all referring to the same molecule)

Key to the value of this blood marker is the specific quality that each and every atherogenic particles (think VLDLs, IDLs, LDLs, sdLDLs, oxLDLs, Lp(a)) has one, and ONLY one Apo B100 protein on it. Contrast this to Apo A, which is a protein found on HDL particles, which can vary in number from 2 to 5 on each HDL particle.

This 1 to 1 ratio of Apo B to atherogenic particle makes the Apo B marker incredibly useful, because it accurately summates the risk of all those pesky disease causing particles by aggregating it into one number. Awesome!

There was recently a paper published that showed that looking at ApoB as a predictor for heart attacks (myocardial infarction) was superior to more traditional metrics such as LDL-c and triglycerides.

Let's look at that paper a bit:

The study by Marston et al. was a prospective cohort analysis involving 389,529 primary prevention patients from the UK Biobank, followed for a median of 11.1 years, and 45,708 statin-treated secondary prevention patients from the FOURIER and IMPROVE-IT trials, followed for a median of 3.6 years.

The main findings of this paper showed:

• ApoB as a Predictor: The study found that apoB levels were a strong predictor of MI risk in both individuals with and without existing atherosclerosis. This suggests that the concentration of apoB-containing lipoproteins is a critical factor in assessing cardiovascular risk.

• Lipoprotein Type and Content: The researchers observed that the type of lipoprotein (e.g., LDL, VLDL) and their cholesterol or triglyceride content did not independently predict MI risk beyond the apoB concentration. This indicates that the number of atherogenic particles, as reflected by apoB levels, is more important than their lipid composition.

• Implications for Risk Assessment: The findings support the use of apoB measurements in clinical practice to better identify individuals at higher risk for myocardial infarction, potentially leading to more targeted and effective prevention strategies.

What is even more interesting about this paper, is that you can see the affects of the Apo B level on the risk of MI on a very short time horizon of 11 years in patient that had not had a prior history of heart disease (primary prevention), and within 3.6 years of those who had a history of heart disease (secondary prevention). Remember from prior blog posts, that the entire process of cardiovascular disease starts in our childhood and takes 60 to 80 years to kill most people. That is a very long and slow process, so seeing a 27% reduction in heart attacks within a decade is clinically meaningful and only starts to show the effect of Apo B levels on a multi-decade long disease process.

This is just one of many papers showing the utility and superiority of using Apo B to help guide clinical management of patients.

The bottom line: Know your Apo B level!

LINK TO PAPER

Marston NA, Giugliano RP, Melloni GEM, Park JG, Morrill V, Blazing MA, Ference B, Stein E, Stroes ES, Braunwald E, Ellinor PT, Lubitz SA, Ruff CT, Sabatine MS. Association of Apolipoprotein B-Containing Lipoproteins and Risk of Myocardial Infarction in Individuals With and Without Atherosclerosis: Distinguishing Between Particle Concentration, Type, and Content. JAMA Cardiol. 2022 Mar 1;7(3):250-256. doi: 10.1001/jamacardio.2021.5083. PMID: 34773460; PMCID: PMC8590731.