ApoC-III proteoforms are associated with better lipid, inflammatory, and glucose profiles independent of total apoC-III

Apolipoprotein (apo) C-III is involved in several processes that increase triglyceride levels, inflammation, and insulin resistance. Four of its proteoforms have been the focus of several studies and have shown differential associations with cardiovascular risk biomarkers, mostly lipids. However, there are other proteoforms of apoC-III that have not yet been investigated in detail. The aim of this study was to evaluate the associations of seven apoC-III proteoforms with a comprehensive set of biomarkers, including lipid metabolism, inflammation, and glucose homeostasis. Seven apoC-III proteoforms (apoC-III , apoC-III , apoC-III , apoC-III , apoC-III , apoC-III , and apoC-III ) were measured using a mass spectrometry immunoassay in 875 participants from the cross-sectional study of the Di@bet.es cohort. The complete lipoprotein profile was obtained via the Liposcale test, and the proton nuclear magnetic resonance ( H-NMR)-assessed glycoprotein signals were also obtained as biomarkers of inflammation. Three proteoform ratios (apoC-III , apoC-III , and apoC-III normalized to apoC-III ) showed protective associations with most of the cardiovascular risk biomarkers in comparison with total apoC-III in linear regression models and were negatively associated with triglycerides (β=-0.173, p