Histological, Immunohistochemical, Morphometric and Molecular Changes in the Wall of Human Varicose Veins

Abstract

Background: Varicose veins (VVs) are a major chronic venous disease, yet the underlying mechanisms are unclear. This disorder is characterized by progressive architectural remodeling of the vessel wall. Recent studies have focused on the role of matrix metalloproteinases (MMPs) in the pathogenesis of VVs. Aim of Study: The present study was assigned to demonstrate the morphologic and morphometric changes in the wall of VVs and to correlate these changes with the expression of MMP-1 and MMP-9. Material and Methods: A total number of 18 human long saphenous vein samples (8 normal and 10 VVs) were included in the study. The specimens were processed and examined histologically using hematoxylin and eosin, Masson's trichrome and orcein, together with immunohistochemistry for alpha smooth muscle actin (Éø-SMA). The mRNA expression of MMP-1 and MMP-9 was analyzed using real-time polymerase chain reaction (PCR). Quantitative morphometric measurements were carried out by the image analyzer. Results: The wall of VVs showed damaged endothelial surface, interrupted internal elastic lamina and numerous vasa vasora. There was significant increase in intima and media thickness compared to normal veins. Significant increase in the mean collagen area percent and decrease in elastin area percent was also observed. The mean area percent of Éø-SMA immunostaining and count of smooth muscle cells (SMCs) showed significant increase, indicating SMCs hypertrophy and hyperplasia, while the optical density of Éø-SMA immunostaining decreased. These changes were associated with significant increase in mRNA expression of MMP-1 and MMP-9. Conclusion: Varicose veins showed marked disorganization in all components of the vessel wall (collagen, elastin and SMCs). The associated increase in mRNA expression of MMPs might be one of the molecular mechanisms underlying vascular remodeling.