Tortuosity and dilatation of veins is a typical sign of varicose veins. Mechanism of tortuosity development and vein dilatation is the major pathogenesis of varicose vein and therefore it is closely related to the risk factors for varicose vein. The greatest known risk factor for varicose vein is body posture to increase hydrostatic pressure. Recent research shows that an increase in venous hydrostatic pressure is sufficient to promote venous remodeling by increasing wall stress and activating venous endothelial and smooth muscle cells. Mechanical forces can alter molecular environment and the activator protein 1 (AP-1) is suggested a prerequisite for venous remodeling. So-called biomechanical mechanism is one of the basic concepts that describe abnormal tortuosity and dilatation of veins. But the most fundamental and significant method for prevention and treatment of varicose vein is still to reduce the venous filling pressure despite the fact that many molecular mechanisms can provide the explanation for the causes of varicose vein. (Korean J Phlebology 2015;14:8-10)

Keywords: Varicose veins, Mechanical stress, Molecular biology, Endothelial cell, Smooth muscle cell