OMICs Signatures Linking Persistent Organic Pollutants to Cardiovascular Disease in the Swedish Mammography Cohort

Cardiovascular disease (CVD) development may be linked to persistent organic pollutants (POPs), including organochlorine compounds (OCs) and perfluoroalkyl and polyfluoroalkyl substances (PFAS). To explore underlying mechanisms, we investigated metabolites, proteins, and genes linking POPs with CVD risk. We used data from a nested case-control study on myocardial infarction (MI) and stroke from the Swedish Mammography Cohort – Clinical (n = 657 subjects). OCs, PFAS, and multiomics (9511 liquid chromatography-mass spectrometry (LC-MS) metabolite features; 248 proteins; 8110 gene variants) were measured in baseline plasma. POP-related omics features were selected using random forest followed by Spearman correlation adjusted for confounders. From these, CVD-related omics features were selected using conditional logistic regression. Finally, 29 (for OCs) and 12 (for PFAS) unique features associated with POPs and CVD. One omics subpattern, driven by lipids and inflammatory proteins, associated with MI (OR = 2.03; 95% CI = 1.47; 2.79), OCs, age, and BMI, and correlated negatively with PFAS. Another subpattern, driven by carnitines, associated with stroke (OR = 1.55; 95% CI = 1.16; 2.09), OCs, and age, but not with PFAS. This may imply that OCs and PFAS associate with different omics patterns with opposite effects on CVD risk, but more research is needed to disentangle potential modifications by other factors.

In Supplemental Text 2. Per-and polyfluoroalkyl measurement and quality control.
The proteins were precipitated using acetonitrile by vigorous shaking for 30 min of thawed samples.After centrifugation, an aliquot of the supernatant was analyzed using liquid chromatography-triple quadrupole linear ion trap mass spectrometry (QTRAP 5500, AB Sciex), using selected reaction monitoring in negative ion mode.For quality control (QC), five QC reference samples, four chemical blanks (water), and calibration standards were analyzed for each sample batch.The limit of detection (LOD) was three times the standard deviation of responses in chemical blanks.QC samples results were used to calculate the between-run precision as the coefficient of variation (2-14%).See supplemental information in Schillemans, T.

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Organochlorine measurement and quality control.POPs, from 200µl of serum/plasma were measured in the Finnish Institute for Health and Welfare (THL).The list of POPs measured included PBDEs each batch of samples (n=39) two reagent blanks were analysed.Average mass in blanks was subtracted from the results serum samples.A NIST Standard Reference Material 1958 for POPs in serum was included in each sample batch.SRM 1958 has certified/reference concentrations for all POPs measured in this study.As the levels of many POPs in the SRM 1958 were relatively high compared to study samples, diluted SRM 1958 was also analysed in each batch.It was SRM 1958 diluted 1 to 9 with new born calf serum that has very low levels of POPs measured.
Summary of results from SRM 1958 and Diluted SRM 1958 are presented in Supplemental Table 1.Also included in Supplemental Table 1 are Limits of Detection (LOD) and Limits of Quantification (LOQ) for each compound.Overall, results show satisfactory accuracy and minor between batch-to-batch variation except for some compounds close to LOD/LOQ.The laboratory participates in interlaboratory comparisons (AMAP interlaboratory comparison Ring Test for Persistent Organic Pollutants in human serum, National Institute of Public Health, Quebec, Canada).

Table 1 .
Results from control serum samples SRM 1958 and diluted SRM 1958 from 39 batches of samples.* Compared to other PCBs, some interferences caused higher CV-% and higher LOD/LOQ for PCB-28.
The laboratory participates in interlaboratory comparisons (University of Erlangen-Nuremberg, Germany and European Human Biomonitoring Initiative).*

Table 2 .
Annotation of 41 metabolite features selected to be associated with POP exposures (OC or PFAS component) and CVD outcomes (MI, stroke or composite).

Table 4 .
Loadings of POP-and CVD-related omics features in OMICs patterns from varimax rotated principal component analysis with a) two sub-patterns or b) four sub-patterns.