Targeted Plasma Proteomics to Predict the Development of Carotid Plaques

Background: Cardiovascular risk stratification in primary prevention is a clinical challenge. We recently identified a large set of circulating proteins improving the risk prediction for cardiovascular events. We now evaluate which of these proteins predicts the development of subclinical carotid atherosclerosis (SCA) in primary cardiovascular prevention. Methods: Three hundred sixty-eight proteins were quantified, by proximity extension assay, from the plasma collected at basal visit from 586 subjects without previous cardiovascular events and without preclinical atherosclerosis. These subjects were reevaluated 11 years after median follow-up (10-12) in a longitudinal observational analysis, to assess the development of SCA, defined as the formation of focal lesion in any carotid tract and detected by carotid ultrasound at basal visit and after follow-up. Common carotid (intima-media thickness [IMT]) was also measured by ultrasound during the same follow-up to identify subjects with faster common carotid intima-media thickness (IMT) progression (increase IMT)>1.3 mm in the common carotid tract). Results: The variation of 68 proteins predicted SCA development and, among them, higher levels of PIgR2 (polymeric immunoglobulin receptor), chemokine (C-C motif) ligand 18, CA1 (carbonic anhydrase 1), Fc gamma receptor IIa and reduced MMP10 (matrix metallopeptidase 10), GT (gastrotropin), IL7R (interleukin 7 receptor) were the most predictive for SCA development. These 7 proteins improved the sensitivity and the specificity for SCA development versus risk factors (age, sex, overweight, hypertension, low HDL-cholesterol, high triglyceride); area under the curve: 0.747 ([0.707-0.784] versus 0.620 [0.577-0.663]; P<0.001). Vice versa, 25 proteins (not in common with the previous 68) predicted faster common carotid IMT progression. Among them, increased IL7D (interleukin 7), chemokine (C-X-C motif) ligand 1, and reduced TNFS13B (TNF superfamily member 13b) significantly increased the sensitivity and the specificity to predict faster common carotid IMT progression as compared with same risk factors (area under the curve: 0.719 [0.680-0.756] versus 0.569 [0.527-0.610]; P<0.001). Conclusions: A new set of circulating proteins have been identified that may be considered as markers of preclinical atherosclerosis development. The difference of the protein identified to predict SCA versus IMT progression may reflect different etiological factors.