Glycosylation Profile of Immunoglobulin G Is Cross-Sectionally Associated With Cardiovascular Disease Risk Score and Subclinical Atherosclerosis in Two Independent Cohorts

Abstract

Rationale: One measure of protein glycosylation (GlycA) has been reported to predict higher cardiovascular risk by reflecting inflammatory pathways.

Objective: The main objective of this study is to assess the role of a comprehensive panel of IgG glycosylation traits on traditional risk factors for cardiovascular disease and on presence of subclinical atherosclerosis in addition to GlycA.

Methods and results: We measured 76 IgG glycosylation traits in 2970 women (age range, 40-79 years) from the TwinsUK cohort and correlated it to their estimated 10-year atherosclerotic cardiovascular disease risk score and their carotid and femoral plaque measured by ultrasound imaging. Eight IgG glycan traits are associated with the 10-year atherosclerotic cardiovascular disease risk score after adjusting for multiple tests and for individual risk factors-5 with increased risk and 3 with decreased risk. These glycans replicated in 967 women from ORCADES cohort (Orkney Complex Disease Study), and 6 of them were also associated in 845 men. A linear combination of IgG glycans and GlycA is also associated with presence of carotid (odds ratio, 1.55; 95% confidence interval, 1.25-1.93; P=7.5×10^-5) and femoral (odds ratio, 1.32; 95% confidence interval, 1.06-1.64; P=0.01) plaque in a subset of women with atherosclerosis data after adjustment for traditional risk factors. One specific glycosylation trait, GP18-the percentage of FA2BG2S1 glycan in total IgG glycans, was negatively correlated with very-low-density lipoprotein and triglyceride levels in serum and with presence of carotid plaque (odds ratio, 0.60; 95% confidence interval, 0.50-0.71; P=5×10^-4).

Conclusions: We find molecular pathways linking IgG to arterial lesion formation. Glycosylation traits are independently associated with subclinical atherosclerosis. One specific trait related to the sialylated N-glycan is negatively correlated with cardiovascular disease risk, very-low-density lipoprotein and triglyceride serum levels, and presence of carotid plaque.

Keywords: atherosclerosis; cardiovascular disease risk; glycosylation; immunoglobulin G; plaque, atherosclerotic.

Figure 1.

Discovery: the role of glycan traits on cardiovascular risk estimates was tested on 3281 samples available. Having identified traits significantly associated with cardiovascular disease risk, we replicated them first, in an independent cohort, validated them in men, and then investigated whether any of these associations could be exclusively explained by any of the individual factors that constitute the ACC/AHA 10-y atherosclerotic cardiovascular disease (ASCVD) risk estimate. The traits that remained associated were then tested for association with presence of subclinical atherosclerosis adjusting for the potential confounders. A subanalysis was performed for the IgG glycan GP18 (% of FA2G2S1 glycan among IgG where FA2G2S1 is the 2-AB mono-sialylated-, galactosylated biantennary N-glycan, core-substituted with fucose), which is strongly negatively correlated with very-low-density lipoprotein (VLDL). ACC indicates American College of Cardiology; AHA, American Heart Association; GP, glycan peak; GlycA, glycoprotein acetylation; ORCADES, Orkney Complex Disease Study; NMR, nuclear magnetic resonance; and UPLC, ultra performance liquid chromatography.

Figure 2.

Glycan traits significantly associated with ACC/AHA 10-y atherosclerotic cardiovascular disease risk score in the discovery, replication, and meta-analysis. Analyses adjusted by age, sex, body mass index, family relatedness, and multiple testing. ACC indicates American College of Cardiology; AHA, American Heart Association; CI, confidence interval; FBS, sialylated fucosylated structures with bisecting GlcNAc; FG, fucosylated galactosylated structures without bisecting GlcNac; FGS, sialylated fucosylated galactosylated structures without bisecting GlcNAc; FS, sialylated fucosylated structures without bisecting GlcNAc; and GP, glycan peak.

Figure 3.

Glycan traits and atherosclerotic cardiovascular disease (ASCVD) components. Each cell of the matrix contains the regression coefficient between one glycan trait and a component of the 10-y ASCVD risk score and the corresponding P value. The table is color coded by correlation according to the table legend (red for positive and blue for negative correlations). ASCVD indicates 10-y ASCVD risk score; ASCVD_HDL, 10-y ASCVD risk score adjusted for covariates and HDL cholesterol; ASCVD_HOMA, 10-y ASCVD risk score adjusted for covariates and insulin resistance; ASCVD_SMK, 10-y ASCVD risk score adjusted for covariates and smoking; ASCVD_TC, 10-year ASCVD risk score adjusted for covariates and TC; CAR, carotid plaque; CAR_SMK, CAR adjusted for covariates and smoking; FEM, femoral plaque; FEM_SMK, FEM adjusted for covariates and smoking; HDL, high-density lipoprotein; HOMA, homeostasis model assessment insulin resistance; SMK, smoking; and TC, total cholesterol.

Figure 4.

Combined glycan score vs cardiovascular disease risk and measures of subclinical atherosclerosis. A, Box plot showing the distribution of the glycan score in quintiles of the 10-y atherosclerotic cardiovascular disease (ASCVD) risk score. B, Box plot showing the distribution of the glycan (IgG+GlycA) score in individuals with and without carotid plaque. P values and odds ratios (OR) from logistic regression adjusted for log (10-y ASCVD risk score). C, Box plot showing the distribution of the log (10-y ASCVD risk score) in individuals with and without carotid plaque, OR and P value adjusted for glycan score. D, Box plot showing the distribution of the glycan score in individuals with and without femoral plaque. P value and OR adjusted for log (10-y ASCVD risk score). E, Box plot showing the distribution of the log (10-y ASCVD risk score) in individuals with and without femoral plaque, OR and P value adjusted for glycan score. CI indicates confidence interval.

Figure 5.

Association between GP18 (% of FA2G2S1 glycan among IgG where FA2G2S1 is the 2-AB mono-sialylated-, galactosylated biantennary N-glycan, core-substituted with fucose), carotid plaque and circulating levels of VLDL. A, Box plot showing the distribution of the IgG glycan trait GP18 in individuals with and without carotid plaque. The P values shown are unadjusted and adjusted for circulating levels of very-low-density lipoprotein (VLDL). B, Correlation between circulating VLDL and GP18. C, Distribution of VLDL in individuals with and without carotid plaque. The P values shown are unadjusted and adjusted for levels of GP18.