Haemin-enhanced expression of haem oxygenase-1 stabilizes erythrocyte-induced vulnerable atherosclerotic plaques.
OBJECTIVE
Previous studies demonstrated that intraplaque haemorrhage increased the contents of cholesterol and oxidants in atherosclerotic plaques. The present study was aimed to test the hypothesis that enhanced expression of haem oxygenase-1 (HO-1) may stabilize vulnerable plaques.


METHODS
Intravascular ultrasound (IVUS) was performed to identify three similar abdominal aortic plaques in each of 58 fat-fed New Zealand rabbits after aortic balloon injury. With the guidance of IVUS, 50 microL autologous erythrocytes (RBC) or normal saline (NS) were injected from adventitia into two of the pre-selected plaques, respectively, whereas the third plaque served as a blank control. All rabbits were randomly divided into two groups, receiving intraperitoneal injection of haemin and saline respectively.


RESULTS
Compared with NS or control plaques, RBC plaques had more macrophage infiltration and lipid content, thinner plaque fibrous cap, and higher expression of inflammatory factors and incidence of plaque rupture. RBC plaques in the haemin group had about a 50% lower incidence of plaque rupture than those in the control group.


CONCLUSIONS
Haem oxygenase-1 may eliminate haem or other oxidants, exert unexpected anti-oxidative and anti-inflammatory effects and serve as a promising approach to the direct inhibition of erythrocyte-induced plaque instability.
Lin
Hui Li
HL
Shandong University Qilu Hospital, Jinan, Shandong, China.
Zhang
Lei
L
Liu
Chun Xi
CX
Xu
Xin Sheng
XS
Tang
Meng Xiong
MX
Lv
Hui Xia
HX
Li
Chang Jiang
CJ
Sun
Hui Wen
HW
Zhang
Mei
M
Hong
Jiang
J
Zhang
Yun
Y
D000818:Animals; D001012:Aorta, Abdominal; D050197:Atherosclerosis / Q000473:pathology*; D004912:Erythrocytes / Q000378:metabolism*; D005786:Gene Expression Regulation; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism*; D006427:Hemin / Q000494:pharmacology*; D050356:Lipid Metabolism; D008264:Macrophages / Q000378:metabolism; D011817:Rabbits; D018084:Ultrasonography, Interventional
D006427:Hemin; D051547:Heme Oxygenase-1