Endothelial cell dynamics and complexity theory.
OBJECTIVE: To apply complexity theory to understanding endothelial cell function in health and disease. DATA SOURCES AND STUDY SELECTION: Published research and review articles in the English language related to complexity theory and endothelial cell biology. DATA EXTRACTION AND SYNTHESIS: The results of published studies have been used to generate a hypothesis of nonlinear dynamics in endothelial cell biology. CONCLUSIONS: The endothelium displays nonlinear complexity. I propose a model in which healthy endothelium retains a broad range of responses and is therefore highly active, whereas dysfunctional endothelium becomes locked into a narrow range of responses, approaching a single steady state and eventual quiescence. These concepts lay a foundation for understanding the pathophysiology of endothelial cell dysfunction in the multiple organ dysfunction syndrome.