Oscillatory Turbulent Flow in Chronic Venous Disease Induces Pro-inflammatory and Reparative Biological Signaling.

Abstract

Background: Despite in vitro studies demonstrated expression of cytokines when endothelial cells are stressed with oscillatory flow, in vivo evaluations are still lacking.The aim of this blinded case-control study was to find correlations between altered venous hemodynamics and induced endothelial signaling, in an in vivo setting. Methods: Fifty-four chronic venous disease (CVD) patients (C24EpAsPr) who underwent varicose veins surgery were included into the study. Into the venous segments that subsequently were going to be surgically ablated, we assessed the followings by echo-color-Doppler (ECD): peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI), and reflux time (RT). The vein samples were sent to the lab, where both an electronic microscopic evaluation and a vascular endothelial cells (VEC) cultivation, with released cytokines quantification and endothelial migration and proliferation characterization, were performed. Five saphenous vein samples were used as controls. Results: The hemodynamic assessment provided the following: PSV (29 + 13 cm/s), EDV (-8 + 6 cm/s), RI (1.31 + 0.19), RT (2.66 + 0.46 s). The microscopic evaluation demonstrated in CVD a derangement on the endothelium layer directly correlating with the CEAP class severity. An erythrocyte progressive sticking was observed as a possible consequence of increased adhesion molecules expression. Twenty-one VEC samples came out from the purification process. In CVD, we assessed a significant increased level of NF-kB, a nuclear transcriptional factor linked with expression of adhesion molecules and several pro-inflammatory cytokines. OPG and VEGF were assessed to be significantly higher both in the supernatants and in the serum assays. We investigated possible correlation between hemodynamic parameters and cytokines assessed in the VEC. The spontaneous and TNFa-induced cytokines release quantification highlighted statistical significant correlations with several hemodynamic parameters. The most significant one was between PDGF and RT, both in basal (r 1⁄4 0.5446, P 1⁄4 .0150) and TNFa-induced (r 1⁄4 0.5448, P 1⁄4 .0150) conditions. While the VEC migration capacity was lower in CVD than in controls, its proliferation trend was higher (P < .05). Conclusions: To our knowledge this is the first study correlating hemodynamic physic parameters with biochemical endothelial signaling, in vivo. As in vitro demonstrated, PDGF is one of the main actors in smooth muscle cell remodeling, reactive oxygen species production, and venous wall derangement. Our data confirm this action in vivo, adding the correlation with the physic forces expressed by the refluxing flow. For the first time, several cytokines involved in biochemical signaling demonstrates to be modulated by hemodynamic parameters. These preliminary results could pave the way for a deeper comprehension of the translation path, which, from the oscillatory flow, leads to the morphological and biochemical alterations detected in the CVD endothelial cells.