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Expression of intercellular adhesion molecule-1 in human coronary endothelial and smooth muscle cells after
1Department of Internal Medicine II-Cardiology, University of Ulm, Germany.
Insights
Tumor necrosis factor-alpha (TNF-alpha) upregulates intercellular adhesion molecule-1 (ICAM-1) expression in human coronary smooth muscle cells and endothelial cells. This suggests TNF-alpha plays a role in inflammatory processes contributing to restenosis after angioplasty.
Area of Science:
- Cardiovascular Biology
- Immunology
- Cellular Adhesion
Background:
- Intercellular adhesion molecule-1 (ICAM-1) is crucial in early post-angioplasty restenosis.
- Investigated in-vitro ICAM-1 expression in coronary cells stimulated by tumor necrosis factor-alpha (TNF-alpha).
Purpose of the Study:
- To examine the effect of TNF-alpha on ICAM-1 expression in human coronary endothelial cells and smooth muscle cells (SMC).
- To understand the role of TNF-alpha in the context of post-angioplasty restenosis.
Main Methods:
- Isolated human coronary smooth muscle cells (HCMSMC, HCPSMC) and endothelial cells (HCAEC, HUVEC).
- Stimulated cells with varying doses of TNF-alpha (2.5-20 ng/ml) for 24 hours.
- Measured cell proliferation and analyzed ICAM-1 surface expression via immunofluorescence microscopy and flow cytometry.
Main Results:
- TNF-alpha increased proliferation in HCPSMC and HCMSMC, but not significantly.
- TNF-alpha significantly reduced proliferation in HUVEC and HCAEC.
- TNF-alpha dose- and time-dependently upregulated ICAM-1 expression in all cell types.
- Maximal TNF-alpha stimulation resulted in stronger ICAM-1 expression in HCMSMC compared to HCPSMC.
Conclusions:
- TNF-alpha regulates ICAM-1 expression in human coronary endothelial cells and SMC.
- These findings highlight TNF-alpha's potential role in the inflammatory pathophysiology of restenosis.
Background:
The intercellular adhesion molecule-1 (ICAM-1) is one of several human cell adhesion molecules that play a critical role in the early stages of postangioplasty restenosis. In this study, the in-vitro expression of ICAM-1 in human coronary endothelial cells and human coronary smooth muscle cells (SMC) after stimulation with tumor necrosis factor-alpha (TNF-alpha) was investigated.
Methods And Results:
SMC were isolated from the media of normal human coronary arteries (n = 26) up to 10 h post mortem (HCMSMC) and from human atherosclerotic coronary arteries (HCPSMC) that were extracted by thrombendarterectomy (n = 25). Endothelial cells of human coronary arteries (HCAEC) were purchased from Clonetics (Cell System, Remagen, Germany), and endothelial cells from human umbilical cord veins (HUVEC) were isolated after vaginal delivery. For investigations of the effect of TNF-alpha (2.5, 5, 10, and 20 ng/ml) on the proliferative activity of HUVEC, HCAEC, HCPSMC, and HCMSMC, serum-free media was used. After 24 h cell number and cell size distribution were measured in a cell analyzer system. The proliferation of HCPSMC and HCMSMC was increased by TNF-alpha; however, significant differences compared with controls were not reached. The proliferation of HUVEC and HCAEC was significantly reduced by TNF-alpha. For investigations of the effect of TNF-alpha (2.5, 5, 10, and 20 ng/ml) on the surface expression of ICAM-1, monoclonal anti-ICAM-1 antibodies (84H10) were used. The expression of ICAM-1 was analyzed using an immunofluorescence microscope. For flow cytometry analysis, 5 x 10(3) cells (100% gated) were analyzed using a fluorescence-activated cell sorter. In control cultures with no stimulation, the expression of ICAM-1 was positive in HCAEC, HCPSMC, HCMSMC, and HUVEC. TNF-alpha stimulated the expression of ICAM-1 in a time- and dose-dependent manner. After maximal stimulation with TNF-alpha (20 ng/ml for 24 h), the expression of ICAM-1 was stronger in HCMSMC than in HCPSMC.
Conclusions:
These results suggest that the cytokine TNF-alpha regulates the expression of ICAM-1 in both human coronary endothelial cells and SMC, and could therefore play an important role in the pathophysiology of inflammatory and immune processes in restenosis after angioplasty.