2001 Fiscal Year Final Research Report Summary
Anastomotic Stenosis is a Cause of Intimal Hyperplasia at the Middle Portion of Arterial Graft
| Project/Area Number |
12671336
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thoracic surgery
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| Research Institution | Kansai Medical University |
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Principal Investigator |
OSAKO Motohiko Kansai Medical University Faculty of medicine,Assistant Professor, 医学部, 助手 (90223784)
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| Co-Investigator(Kenkyū-buntansha) |
OTANI Hajime Kansai Medical University Faculty of medicine, Assistant Professor, 医学部, 講師 (60168979)
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| Project Period (FY) |
2000 – 2001
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| Keywords | neointimal hyperplasia / small vascular anastomosis / arterial auto-graft / shear stress / endothelial cell / nitric oxide synthase |
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| Research Abstract |
Background : Arterial grafts have become a choice of materials for coronary artery bypass surgery. However, patency of arterial grafts depends on the quality of anastomosis, and anastomotic stenosis is a cause of bypass failure. Anastomotic stenosis alterflow conditions within the grafts not only at the proximity of anastomosis but also at the middle portion of the graft that may leads to intimal hyperplasia (IH) by modifying endothelial functio. Methods and Results : Freshly prepared thoracic aorta from RT11 rats were transplanted to the abdominal aorta of the same strain. Proximal or distal anastomotic site was banded to create a luminal size of 50-75% of the original graft. The difference in flow velocity (M/m2) between the host abdominal aorta at the proximity of the anastomosis and the middle portion of the graft was significantly greater in proximal stenosis (PS) group (0.78+/-0.18) and in distan stenosis (DS) group (0.53+/-0.03) than in no-stenosis (NS) group (0.19+/-0.09). IH a
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s assessed by the ratio of intimal/medial are (%) at the middle portion of the graft 30 days after surgery was significantly reater in PS group (48.3+/-6.7) and in DS group (21.3+/-4.3) than in NS group (6.0+/-2.5). There was a significant negative correlation between the severity of stenosis and the degree of IH in each group. However, PS produced significantly greater IH compared with DS when the degree of anastomotic stenosis was identical. Immunohistochemical analysis revealed significantly less number of nitric oxide synthase type 3 (NOS3)-positive endothelial cells in PS and DS groups than in NS group. NOS3-positive endothelial cells were significantly less in PS group tha in PD group.
Conclusions : These results suggest that anastomotic stenosis of arterial grafts either proximal or distal is an important determinant for IH at the middle portion of the graft. However, the degree of IH is more prominent in PS than in PD when the severity of anastomotic stenosis is identical. Impaired nitric oxide synthesis by endothelial cells associated with reduced flow velocity and modulation of other undertermined mechanical forces may be involved in this pathogenesis. Less
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