90th Annual Meeting Abstracts
Cyclic Strain in Endothelial Cells Delays the Expression of Tissue Factor Induced by Thrombin in a 6 Hours Time Course
*NORIO YAMASHITA, *Adrienne Rochier, *Alexander Nixon, Bauer Sumpio
Yale university School of Medicine, New Haven, CT
Objective:We investigated whether mechanical stimuli such as cyclic stretch (CS) and orbital shear stress (OSS) interact with Thrombin (Thr) in the expression of TF.
Design:Non-randomized control study. Human umbilical vein EC (HUVEC) were exposed to CS or OSS in the presence or absence of Thr and then evaluated for TF expression compared to controls.
Setting:Basic Science Research Laboratory
Interventions:HUVEC were either cultured on gelatin coated flexible membranes or culture dishes. When HUVEC attained sub-confluence they were subjected to 2, 4 and 6 hrs of 10% average CS at 60 cycle/min with or without Thr. HUVECs in dishes were exposed to the same time-course of OSS (11 dynes/cm2) with or without Thr. TF expression was determined using RT-PCR with b-actin as the reference gene. Fold changes were calculated using the Pfaffl method and expressed as mean±SE (N=3).
Main Outcome Measures:Levels of TF expression as estimated with the use of RT-PCR.
Results:CS and HOSS for up to 6 hours had minimal effect on TF expression in HUVEC. TF expression of Thr stimulated HUVEC peaked at 2 hrs (4.45±1.66, 2.89±0.52 and 2.22±0.73 respectively). Combination of CS+Thr, led to a peak at 4 hrs (3.77±1.22, 4.28±1.54 and 3.21±1.11 respectively), while combination of HOSS+Thr did not change pattern of TF expression in time-course.
Conclusions:Exposure of HUVEC to CS delays the activation of TF expression induced by Thr, while OSS did not have an effect. These results indicate that distinct mechanical stimuli have differential effects on HUVEC gene expression and suggest novel temporal interactions between signal transmission cascades from CS and Thr.