Ion Mobility Lipoprotein Subfractionation: Further Beyond Cholesterol

What is Ion Mobility Lipoprotein Subfractionation?

Ion mobility lipoprotein subfractionation is another method used to evaluate the size and number of the lipoproteins that carry lipids and other compounds in the blood. This technique uses gas-phase differential electrical mobility to separate lipoproteins, a direct method of assessing lipoprotein subclasses. The ion mobility technique is considered comparable to analytical ultracentrifugation, and segmented gradient gel electrophoresis, and research utilizing these methods may be extrapolated to ion mobility (Quest Cardio IQ® FAQs).

The Quest Cardio IQ ion mobility test focuses on the lipoprotein particle characteristics that significantly correlate with atherogenic phenotype and cardiovascular events evaluated in the Malmo Diet and Cancer Study (Musunuru 2009, Mora 2015): 

Small, medium, and total LDL particle numbers

• Elevated LDL particle number is associated with a 1.2-1.4-fold increased risk of CVD.

• Increased small and medium LDL particle number is also associated with a 1.2-1.4-fold increase in CVD risk as well.

LDL peak size and associated LDL pattern

• Smaller denser LDL particles (sdLDLs) are considered more atherogenic
• More small and medium LDL particles are usually associated with fewer large HDL particles
• LDL pattern A (optimal) comprises larger more buoyant LDL particles whereas LDL pattern B (high-risk) comprises predominantly small dense LDLs

Large HDL particle number

• • Antioxidant properties of large HDLs are protective, therefore a reduced number of large HDLs increases CVD risk.

Some Answers to Common Questions Regarding Ion Mobility:

What do the results of the ion mobility lipoprotein subfractionation mean?

An ion mobility lipoprotein subfractionation helps identify an atherogenic lipid profile even if total or LDL-cholesterol are within normal range.

An increased level of small dense LDL particles (sdLDLs), along with elevated fasting triglycerides and lower levels of large HDLs, represent the most atherogenic pattern/phenotype (Musunuru 2009). Identification of this pattern can help assess relative risk of oxidative stress and atherosclerosis and help guide treatment and lifestyle interventions.

Small dense LDLs are more susceptible to oxidation, can more easily penetrate the artery wall, and are considered highly atherogenic (Ivanova 2017). In a small study of 170 individuals with diabetes or metabolic syndrome, higher sdLDL levels were found to correlate strongly with higher levels of triglycerides and may contribute to coronary artery calcium (CAC). However, larger LDLs and HDLs may reduce the risk of CAC. Interestingly LDL-cholesterol was not associated with CAC (Aneni 2019).

Where can you order ion mobility lipoprotein subfractionation?

The Cardio IQ® Ion Mobility test includes small, medium, and total LDL particle numbers, LDL peak size and associated LDL pattern, and large HDL particle number. This test also measures triglycerides, total-, LDL-, HDL-, non-HDL-cholesterol, ApoB, and Lp(a) as well for further CVD risk assessment. Some commercial labs and direct access companies may offer the Ion Mobility Lipoprotein Subfractionation test.

Is ion mobility the same as NMR lipoprotein subfractionation?

Ion mobility is not the same as NMR which is an indirect method that uses nuclear magnetic resonance spectroscopy for its subfractionation evaluation. Ion mobility is a direct measurement of particle number and size, a process that requires more extensive preparation than NMR (AACC 2017).

Lastly, are the Cardio IQ Ion Mobility Biomarkers in the ODX software?

Yes! 

Feel free to add results for these biomarkers into the software. Lab importing will pull the results in and we have added all 5 ION biomarkers to the default templates.

References

American Academy of Clinical Chemists (AACC). Lipoprotein Subfractionation Analysis: The Continuing Quest for Improving Cardiovascular Risk Prediction. January 3, 2017.

Aneni, Ehimen C et al. “Lipoprotein Sub-Fractions by Ion-Mobility Analysis and Its Association with Subclinical Coronary Atherosclerosis in High-Risk Individuals.” Journal of atherosclerosis and thrombosis vol. 26,1 (2019): 50-63. doi:10.5551/jat.40741

Ivanova, Ekaterina A et al. “Small Dense Low-Density Lipoprotein as Biomarker for Atherosclerotic Diseases.” Oxidative medicine and cellular longevity vol. 2017 (2017): 1273042. doi:10.1155/2017/1273042

Mora, Samia et al. “Atherogenic Lipoprotein Subfractions Determined by Ion Mobility and First Cardiovascular Events After Random Allocation to High-Intensity Statin or Placebo: The Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) Trial.” Circulation vol. 132,23 (2015): 2220-9. doi:10.1161/CIRCULATIONAHA.115.016857 

Musunuru K, Orho-Melander M, Caulfield M, et al. Ion mobility analysis of lipoprotein subfractions identifies three independent axes of cardiovascular risk. Arterioscler Thromb Vasc Biol. 2009;29:1975-1980. 

Quest Cardio IQ® Lipoprotein Fractionation, Ion Mobility FAQs