Background: Coronary artery disease (CAD) is a leading cause of death worldwide. Due to its multifactorial nature, individual risk modifiers are difficult to identify, with genetic background and lifestyle both strongly influencing disease development and progression. To investigate how the genetic background modifies endothelial (dys)function, a central pathomechanistic driver, we used induced pluripotent stem cell-derived endothelial cells (iPSC-EC) from ACS patients/healthy donors to assess central cellular functions at rest and upon inflammatory stimulation.

Aim: The Aim of this study is to illuminate differences in iPSC-EC functionality introduced by high-risk CAD patients’ genetic background on a molecular level to pinpoint central disease modifying pathways.

Methods: iPSC from participants with similar lifestyle but different disease status (healthy > 65 y/o, acute coronary syndrome (ACS) < 65y/o) were differentiated into iPSC-EC. Cells were exposed to proinflammatory stimulation via tumour necrosis factor alpha (TNF-α) as well as pro- and anti-atherogenic flow conditions for assessment of leukocyte (THP-1) adhesion. Furthermore, DNA-methylation was assessed via bisulphite sequencing in iPSC and in iPSC-EC at passage 4.

Results: ACS-iPSC-EC showed a significantly stronger upregulation of E-selectin in response to inflammatory stimulation with TNF-α than healthy iPSC-EC on mRNA level (ACS: 532,1-fold±48,7 vs. healthy: 322,3-fold±55,7; p=0,02). Similarly, ICAM1 protein upregulation was stronger in ACS-iPSC-EC than in healthy iPSC-EC as assessed by flow cytometry (ACS: 1.4-fold±0,01 vs. healthy: 1,1-fold±0.0007; p<0,001) whereas VCAM1 upregulation was weaker in ACS-iPSC-EC compared to healthy iPSC-EC (ACS: 1,8-fold±0.3 vs. healthy: 4.2-fold±0.9; p<0.001). ACS-iPSC-EC also recruited more THP-1 per view field under atheroprotective (high shear stress, laminar) flow conditions (ACS: 78,4±20,7 vs. healthy: 33,25±12,3; p=0,04). Under proatherogenic flow conditions, there was no difference in absolute THP-1 adhesion per view field (ACS: 302±38,9 vs. healthy: 340±70,4, p=0,43). Both groups showed a negative calculated mitotic age at the stem cell stage based on DNA-methylation, without a significant group difference (ACS: -14,1±0,86 vs. healthy: -13,7±0,83; p=0,376).

Conclusion: Stronger upregulation of specific cellular adhesion molecules (E-Selectin, ICAM1) in ACS-iPSC-EC compared to healthy iPSC-EC in response to inflammatory stimulation and stronger basal leukocyte recruitment hint at intrinsic differences in inflammatory pathways at rest and upon activation that could contribute to faster disease development.