Abstract 6949: Particulate Matter Increases Inflammation and Impairs Electrical Activity in IPSC-Derived Cardiac Organoids

Abstract

Introduction: Exposure to particulate matter (PM) is associated with increased heart failure (HF) hospitalizations and death. Animal models to study PM-related cardiovascular disease (CVD) are complicated by effects on multiple organs and differing physiology from humans. A recent alternative is the generation of patient-specific induced pluripotent stem cells (IPSCs) to study interactions between the patient’s genome and environmental factors. Given that the heart relies on a network of cells that participate in the development of CVD, we propose a cardiac organoid (hCO) model to study the effects of PM 2.5 . Hypothesis: We hypothesize that air pollution exposure causes heart remodeling, which exacerbates HF. Methods: IPSCs were differentiated to cardiomyocytes (iCMs), cardiac fibroblasts (iCFs), endothelial cells (iECs) and macrophages (iMø). Cell suspensions containing 50% iCMs and 50% nonmyocyte (4:2:1 ratio of iECs:iCFs:iMø) were mixed and seeded in agarose microwells. Beating hCOs were cultured for 5 days before exposure to 100μg/ml of PM 2.5 for 48h. Immunostaining, qPCR, and Multielectrode Array (MEA) were performed in control (CT) and PM-treated hCOs (PM) (n=10 hCO/ group). Results: Treatment with PM caused loss of hCO circularity (CT:0.86±0.02 vs. PM:0.56±0.08, p<0.05, n=5), changes in the beat amplitude, and more frequent premature extrasystoles. Gene expression analysis showed downregulation of SCN5A and upregulation of TNNT2 and GJA1 . Upregulation of inflammatory markers such as IL6 , IL1b , CD80 , and TNFa was also observed in PM-treated hCOs. Moreover, PM caused upregulation of MMP1 , CCL2 , CASP3 , SOD1 , and SOD2 . MEA experiments revealed a longer FPD duration and a decrease in spike slope and beating period along with shortening of the action potential (APD90: CT 577±20ms vs. PM 489±16ms, p<0.05, n=10) and higher beat period irregularity (CT 3.2±0.7% vs. PM 13.1±1.6%, p<0.001, n=10). Conclusions: We conclude that PM plays a direct role in the development of CVD, increasing inflammation, apoptosis, oxidative stress, and affecting the electrophysiology of the heart. Further studies in hCOs from HF patients will provide evidence of the effects of PM on the phenotype of the disease.