Role of nitric oxide and inducible nitric oxide synthase in human abdominal aortic aneurysms: a preliminary study.
BACKGROUND
Nitric oxide (NO) is an important mediator in the pathophysiology of many vascular diseases. However, the definite role of NO in human abdominal aortic aneurysm (AAA) formation is unclear. The aim of this study was to investigate production of NO and expression of inducible nitric oxide synthase (iNOS), and their possible role in AAA.


METHODS
A total of 28 patients with AAA, 10 healthy controls, and 8 patients with arterial occlusive disease were enrolled into this study. Standard colorimetric assay was used to examine NO concentration in plasma from patients with AAA and normal controls, and in cultured smooth muscle cells (SMCs). Expression of iNOS in aortas and cultured SMCs were detected by immunochemistry. The correlation of iNOS expression with age of the patient, size of aneurysm, and degree of inflammation was also investigated by Cochran-Mantel-Haenszel chi2 test and Kendall' Tau correlation.


RESULTS
Expression of iNOS increased significantly in the wall of aneurism in the patients with AAA compared to the healthy controls (P < 0.05) and the patients with occlusive arteries (P < 0.05). iNOS protein and media NOx (nitrite + nitrate) also increased in cultured SMCs from human AAA (n = 4, P < 0.05), while plasma NOx decreased in patients with AAA (n = 25) compared to the healthy controls (n = 20). There was a positive correlation between iNOS protein and degree of inflammation in aneurismal wall (Kendall coefficient = 0.5032, P = 0.0029).


CONCLUSIONS
SMCs and inflammatory cells were main cellular sources of increased iNOS in AAA, and NO may play a part in pathogenesis in AAA through inflammation.
Institute of Vascular Surgery of CPLA, Department of Vascular Surgery, Changhai Hospital, Second Military Medical University, Shanghai 200433, China. liaomf1995@hotmail.com
Ming-fang
MF
Liao
Zai-ping
ZP
Jing
Jun-min
JM
Bao
Zhi-qing
ZQ
Zhao
Zhi-jun
ZJ
Mei
Qing-shen
QS
Lu
Xiang
X
Feng
Rui
R
Feng
Su-zen
SZ
Zhang
Xiao-yan
XY
Li
D000328:Adult; D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000209:etiology*; D017209:Apoptosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D009569:Nitric Oxide / Q000502:physiology*; D052247:Nitric Oxide Synthase Type II / Q000032:analysis / Q000502:physiology*
D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II