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Unique sensitivities to cytokine regulated expression of adhesion molecules in human heart-derived endothelial cells
R M McDouall1, M W Farrar, S Khan
1NHLI, Department of Cardiothoracic Surgery, Imperial College School of Medicine, Royal Brompton and Harefield NHS Trust, Middlesex, UK.
Insights
Coronary endothelial cells show varied adhesion molecule responses to inflammation. Heart microvascular and coronary artery cells are more sensitive to TNFalpha and IL-1beta than aortic root cells, impacting immune cell binding.
Area of Science:
- Cardiovascular Biology
- Immunology
- Cellular Biology
Background:
- Endothelial cell adhesion molecules are critical in inflammation and transplant rejection.
- Differential expression of these molecules in the coronary tree to cytokines is not well understood.
Purpose of the Study:
- To investigate the differential expression of VCAM-1, E-selectin, and ICAM-1 on human endothelial cells from the aortic root, coronary artery, and heart microvasculature.
- To determine the response of these cells to inflammatory cytokines TNFalpha and IL-1beta.
Main Methods:
- Flow cytometry was used to analyze adhesion molecule expression on cultured human aortic root (HAEC), coronary artery (HCAEC), and heart microvascular (HHMEC) endothelial cells.
- Cells were stimulated with varying concentrations of TNFalpha and IL-1beta.
Main Results:
- HCAEC and HHMEC exhibited higher constitutive VCAM-1 and E-selectin levels than HAEC.
- HCAEC and HHMEC showed significantly greater sensitivity to TNFalpha stimulation compared to HAEC.
- IL-1beta induced similar patterns but was less potent; prolonged expression was noted in HHMEC.
- Increased peripheral blood mononuclear cell (PBMC) binding was observed on HCAEC and HHMEC.
Conclusions:
- Endothelial cells from different coronary regions display distinct basal and cytokine-induced adhesion molecule expression patterns.
- These regional differences may influence inflammatory responses and immune cell interactions within the coronary vasculature.
Abstract:
The expression of adhesion molecules by endothelial cells is crucial in many inflammatory processes and plays an active role in the development of reperfusion injury, acute and chronic rejection. The expression of adhesion molecules in different parts of the coronary tree to cytokine stimulation is not known. We describe here a detailed study of the effects of the inflammatory cytokines TNFalpha and IL-1beta on the expression of adhesion molecules vascular cell adhesion molecule-1 (VCAM-1), E-selectin and intracellular cell adhesion molecule-1 (ICAM-1) on human aortic root (HAEC), coronary artery (HCAEC) and heart microvascular (HHMEC)) endothelial cells in culture, using flow cytometry. We found constitutive levels of both VCAM-1 and E-Selectin on HCAEC and HHMEC (approximately 20%) which were significantly higher compared to HAEC (approximately 3%). There was an extreme sensitivity of HCAEC and HHMEC to 0.002 ng/ml TNFalpha: (VCAM-1 approximately 40%, E-Selectin approximately 25%) respectively, compared to HAEC (VCAM-1 approximately 5%, E-selectin approximately 5%). IL-1beta showed a similar pattern of expression at low doses (5 U/ml), but was less potent. We also observed prolonged expression of these adhesion molecules, especially on the HHMEC (>48 hours) compared to HAEC. There was also increased binding of peripheral blood mononuclear cells (PBMC) to both non-stimulated and TNFalpha stimulated HCAEC and HHMEC compared to HAEC. This data suggest that endothelial cells in different regions of the coronary tree express different patterns of basal and cytokine-stimulated adhesion molecule expression.