Endothelial cell dysfunction is accompanied by reduced expression of genes encoding endothelial phenotype markers, basement membrane proteins, and extracellular matrix components. • Primary human coronary artery and internal thoracic artery endothelial cells have distinct molecularprofile of endothelial phenotype markers, basement membrane components, and angiogenic proteins. • In comparison with primary human coronary artery endothelial cells, profile of basement membrane and extracellular matrix components of human internal thoracic artery endothelial cells is more similarto intact endothelial cells. Aim To compare the gene and protein expression profile in primary human coronary artery endothelial cells (HCAEC) and human internal thoracic artery endothelial cells (HITAEC) in physiological and dysfunctional states. Methods To perform an unbiased and high-throughput analysis, we applied RNA sequencing and ultra-high performance liquid chromatography-tandem massspectrometry. Fold change and transcripts per million were used as metrics to evaluate RNA sequencing results. Mass spectrometry data were assessed by ranking the expression of 2,986 detected molecules after measuring areas of respective chromatographic peaks. Results Dysfunctional ECs showed decreased expression of the genes encoding endothelialphenotype markers, basement membrane components, extracellular matrix proteins, and angiogenic molecules, concurrently having higher expression of the genes encoding oxidative and endoplasmic reticulum stress proteins. In comparison to HITAEC, HCAEC had higher expression of angiogenic proteins (including B-type ephrin receptors EPHB2 and EPHB4) and both subunits of endothelial integrin αvβ3 (ITGAV and ITGB3). In turn, HITAEC had higher expression ofendothelial transcription factors ERG and FLI1, angiopoietins (ANGPT2 and ANGPTL2) and their receptors (PTPRB and TEK), VEGF co-receptors (NRP1 и NRP2), and also higher expression of basement membrane and extracellular matrix components which have been overexpressed in the intact ECs (such as laminin, type IV collagen, von Willebrand factor, angiopoietin-related protein 2, biglycan, nultimerin 1, cathepsin С, and ADAMTS4). Conclusion Dysfunctional ECs have lower expression of basement membrane and extracellularmatrix components. HCAEC and HITAEC have significant differences in the molecular profile of endothelial phenotype markers, basement membrane proteins, extracellular matrix components, and angiogenic proteins. © 2026, NII KPSSZ. All rights reserved.