Effect of shear stress on the expression of growth factors in endothelial cells around stent edge

Ancai WANG; Lifang LI; Buchun ZHANG; Ling BAI

ABSTRACT

BACKGROUND:

Alterations in secondary hemodynamics around the stent edge can be caused by stent planted. Is there different effect of shear stress on platelet growth factors-A, B (PDGF-A, B) and basic fibroblast growth factor (bFGF) of endothelial cells around stent edge after stent planted?

OBJECTIVE:

To explore the effect of shear stress on growth factors of endothelial cells around stent edge.

DESIGN:

Observational comparative study.

SETTING:

Department of Cardiology, Yijishan Hospital, Wannan Medical College; Laboratory of Biomechanics (National Laboratory), Medical College of Shanghai Jiao Tong University.MATERIALS The experiment was carried out in the Laboratory of Biomechanics, Medical College of Shanghai Jiaotong University from April to October 2006. The main reagents were detailed as follows trypsin (Hyclon Company); M-199 medium (Gibco BRL Company); fetal bovine serum (Hangzhou Sijiqing Bioengineering Material Institute); aFGF, Heparin and Hepes (Sigma Company); thymide, Ⅷ factor monoclonal antibody (Rabbit anti-human),biotinylated horse anti-rabbit IgG and propidium lodide (Sigma Company); neonate belly band (Delivery Room of Shanghai the Fifth People's Hospital); trizol (Invitrogene Company); reverse transcription polymerase chain reaction (RT-PCR) kit (Fermentas Company); penicillin/streptomycin (AB/M), objective gene primer (Shanghai Bioengineering Company).

METHODS:

Traditional parallel-plate streaming cavity was modified into rectangular and gradient shear stress models;while static group was established at the same time. Two shear stress groups were subjected to 11.37 dyne/cm2 and 5.66-14.38 dyne/cm2 shear stress, respectively for 3 hours, 6 hours and 12 hours.MAIN OUTCOME

MEASURES:

The expressions of PDGF-A, B and bFGF mRNA of human umbilical endothelial cells (HUVECs) were measured by RT-PCR at different time points.

RESULTS:

Compared with static group, the maximal expression of PDGF-A, B and bFGF mRNA was reached peak at 3 hours in gradient shear stress group and this level of PDGF-A mRNA expression remained till 12 hours. in rectangle shear stress group, the peak value of mRNA expression of these growth factors was all reached at 6 hours, and then gradually decreased.

CONCLUSION:

Over-expressions of PDGF-A, B and bFGF induced by gradientshear stress after stent planted may play an important role in stent restenosis through intimal hyperplasia.