Chronic venous insufficiency and varicose veins occur commonly in affluent countries and are a socioeconomic burden. However, there remains a relative lack of knowledge about venous pathophysiology. Various theories have been suggested, yet the molecular sequence of events is poorly understood. Transforming growth factor-beta one (TGF-β1) is a highly complex polypeptide with multifunctional properties that has an active role during embryonic development, in adult organ physiology and in the pathophysiology of major diseases, including cancer and various autoimmune, fibrotic and cardiovascular diseases. Therefore, an emphasis on understanding its signaling pathways (and possible disruptions) will be an essential requirement for a better comprehension and management of specific diseases. This review aims at shedding more light on venous pathophysiology by describing the TGF-β1 structure, function, activation and signaling, and providing an overview of how this growth factor and disturbances in its signaling pathway may contribute to specific pathological processes concerning the vessel wall which, in turn, may have a role in chronic venous insufficiency.

Chronic venous disease (CVeD) is a prevalent condition with a significant socioeconomic burden, yet the pathophysiology is only just beginning to be understood. Previous studies concerning the dysregulation of matrix metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of metalloproteinases (TIMPs)) within the varicose vein wall are inconsistent and disregard clinical progression. Moreover, it is highly plausible that MMP and TIMP expression/activity is affected by transforming growth factor (TGF)-β1 and its signaling receptors (TGFβRs) expression/activity in the vein wall. A case–control study was undertaken to analyze genetic and immunohistochemical differences between healthy (n = 13) and CVeD (early stages: n = 19; advanced stages: n = 12) great saphenous vein samples. Samples were grouped based on anatomic harvest site and subjected to quantitative polymerase chain reaction for MMP1, MMP2, MMP8, MMP9, MMP12, MMP13, TIMP1, TIMP2, TIMP3, TIMP4, TGFβR1, TGFβR2, and TGFβR3 gene expression analysis, and then to immunohistochemistry for immunolocalization of MMP2, TIMP2, and TGFβR2. Decreased gene expression of MMP12, TIMP2, TIMP3, TIMP4, and TGFβR2 was found in varicose veins when compared to controls. Regarding CVeD clinical progression, two facts arose: results across anatomical regions were uneven; decreased gene expression of MMP9 and TGFβR3 and increased gene expression of MMP2 and TIMP3 were found in advanced clinical stages. Most immunohistochemistry results for tunica intima were coherent with qPCR results. In conclusion, decreased expression of TGFβRs might suggest a reduction in TGF-β1 participation in the MMP/TIMP imbalance throughout CVeD progression. Further studies about molecular events in the varicose vein wall are required and should take into consideration the venous anatomical region and CVeD clinical progression.

Objectives Transforming growth factor-beta1 (TGF-β1) may participate in local chronic inflammatory processes in varicose veins and in venous wall structure modifications through regulation of matrix metalloproteinases (MMP) and their inhibitors (tissue inhibitor of metalloproteinase (TIMP)). The aim of this study was to analyze the effect of TGF-β1 in the vein wall, namely on the gene expression of selected MMP, TIMP and TGF-β1 receptors. Methods Healthy vein samples were harvested from eight subjects who underwent coronary bypass graft surgery with great saphenous vein. Each vein sample was divided into two segments, which were cultivated separately in vitro (one of the segments had TGF-β1 added) and then submitted to gene expression analysis. Results In the TGF-β1 supplemented group, there was a general increase in the mean gene expression. Specifically, expression of MMP9, MMP12, TIMP1 and TIMP2 were statistically significant. Conclusion The results of this study demonstrate that the gene expression of MMP9, MMP12, TIMP1 and TIMP2 was influenced by the addition of TGF-β1. These results may be translated to chronic venous insufficiency framework and suggest involvement of TGF-β1 in the vein wall pathology.