[Mechanism of intimal hyperplasia of venous grafts after coronary artery bypass grafting, an experimental study].
OBJECTIVE
To study the mechanism of intimal hyperplasia after coronary artery bypass grafting (CABG) and to find an effective way for preventing intimal hyperplasia.


METHODS
Twenty-four male New Zealand rabbits were randomly divided into two groups of 12 rabbits: operation group and sham-operation (control) group. The external jugular vein was harvested and anastomosed end-to-side to the ipsilateral carotid artery in operation group or grafted in situ in the control group. Six rabbits in each group were killed and their grafted veins were taken 2 weeks and 4 weeks after operation respectively. The mRNA expressions of transforming growth factor beta (TGF-beta), collagen I, collagen III, and angiotension 1 receptor (AT1R) were measured by RT-PCR and electrophoresis.


RESULTS
The intimal hyperplasia was much more remarkable in the operation group than in the control group either 2 weeks or 4 weeks after operation. The mRNA expressions of TGF-beta, AT1R, collagen I, and collagen III were significantly higher in the operation group than in the control group, especially 2 weeks after (P < 0.01). Four weeks after the operation, the expressions of TGF-beta, AT1R, collagen I and collagen III were 4.05 +/- 0.49 vs 2.05 +/- 0.26, 18.23 +/- 1.32 vs 4.61 +/- 0.53, 80 +/- 0.17 vs 0.90 +/- 0.18, and 7.05 +/- 0.68 vs 2.80 +/- 0.17 respectively (all P < 0.05).


CONCLUSIONS
TGF-beta and AT1R may have an important role in the intimal hyperplasia of venous graft in CABG. Continuous arterial pressure may be the main factor of increased expression of TGF-beta and AT1R that cause the enormous synthesis and deposit of collagen.
Xiao
Mingdi
M
Department of Cardiovascular Surgery, Shanghai First People's Hospital, Shanghai 200080, China.
You
Wenjun
W
Yuan
Zhongxiang
Z
Xu
Genxing
G
D000818:Animals; D024042:Collagen Type I / Q000235:genetics; D024061:Collagen Type III / Q000235:genetics; D001026:Coronary Artery Bypass; D005260:Female; D015870:Gene Expression; D006965:Hyperplasia / Q000235:genetics; D007601:Jugular Veins / Q000378:metabolism / Q000473:pathology / Q000637:transplantation*; D008297:Male; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D044140:Receptor, Angiotensin, Type 1; D011945:Receptors, Angiotensin / Q000235:genetics; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000235:genetics; D017539:Tunica Intima / Q000378:metabolism / Q000473:pathology*
D024042:Collagen Type I; D024061:Collagen Type III; D012333:RNA, Messenger; D044140:Receptor, Angiotensin, Type 1; D011945:Receptors, Angiotensin; D016212:Transforming Growth Factor beta