Human gastroepiploic artery has greater chymase activity than the internal thoracic artery.
OBJECTIVE
Recent reports have demonstrated that long-term patency of the gastroepiploic artery (GEA) in coronary artery bypass grafting (CABG) is less satisfactory compared with the internal thoracic artery (ITA). However, the reason has not been fully elucidated. Angiotensin II is known to play an important role in the development of intimal hyperplasia, we hypothesized that the GEA is different from the ITA with respect to angiotensin II-forming ability. Accordingly, we measured activities of angiotensin II-forming enzymes, angiotensin-converting enzyme (ACE) and chymase, in human GEA and ITA.


METHODS
Remnant of the GEAs and ITAs were obtained from 24 patients who underwent CABG in which both conduits were used simultaneously. Activities of ACE and chymase were measured by using the extract form the GEA or ITA. Sections of the GEA or ITA were immunohistochemically stained with anti-human chymase antibody.


RESULTS
The ACE activity of the GEA (0.28+/-0.16 mU/mg protein) was greater than that of the ITA (0.18+/-0.11, p < 0.001). The chymase activity of the GEA (11.11+/-7.15 mU/mg protein) was also greater than that in the ITA (7.13+/-4.89, p < 0.001). The density of chymase-positive cells in the GEA (3.8+/-4.2 cells/mm2) was greater than that in the ITA (1.1+/-1.2, p < 0.01).


CONCLUSIONS
Activities of both ACE and chymase were significantly greater in the GEA compared with the ITA. The GEA may be different from the ITA with respect to potential ability of angiotensin II-formation.
Soga
Yoshiharu
Y
Department of Cardiovascular Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Takai
Shinji
S
Okabayashi
Hitoshi
H
Nagasawa
Atsushi
A
Yokota
Tadaaki
T
Nishimura
Kazunobu
K
Miyazaki
Mizuo
M
Komeda
Masashi
M
D000368:Aged; D053818:Chymases / Q000378:metabolism*; D001026:Coronary Artery Bypass; D005260:Female; D024405:Gastroepiploic Artery / Q000201:enzymology* / Q000473:pathology; D006801:Humans; D007124:Immunoenzyme Techniques; D007387:Internal Mammary-Coronary Artery Anastomosis; D008297:Male; D008323:Mammary Arteries / Q000201:enzymology* / Q000473:pathology; D008875:Middle Aged; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism
D007703:Peptidyl-Dipeptidase A; D053818:Chymases