Immunohistochemical evaluation of three nitric oxide synthase isoforms in human saphenous vein exposed to different degrees of distension pressures.
The effect of short duration and different degrees of distension pressures was investigated by means of immunohistochemistry of the three nitric oxide synthase isoforms in the human saphenous vein conventionally harvested from 20 patients submitted to coronary artery bypass graft. The human saphenous vein distal portion was divided into four segments, each one allocated to a different group. In Group I (control group), the human saphenous vein segment was not exposed to distension pressure. In Groups II, III, and IV, the human saphenous vein segment was exposed to 100, 200, and 300 mmHg of distension pressure, respectively. The distension pressures were applied and maintained with Krebs solution for 15 s. The human saphenous vein of the control group presented endothelial nitric oxide synthase and neuronal nitric oxide synthase in both endothelial and smooth muscle cells, while the inducible nitric oxide synthase appeared predominantly in the medial layer. Neither 100 nor 200 mmHg of pressurization affected the immunostaining of any nitric oxide synthase isoform. However, the human saphenous vein segments exposed to 300 mmHg of distension pressure showed a reduction in endothelial nitric oxide synthase content in the endothelium, but not in the tunica media. This lower endothelial nitric oxide synthase immunostaining in the intimal cells was associated with endothelial denudation. Therefore, we conclude that care should be taken when handling the human saphenous vein since just a few seconds of distension pressure above the normal systemic pressure can be sufficient to disrupt the endothelium reducing the amount of endothelial nitric oxide synthase and impairing the graft quality.
Viaro
Fernanda
F
Department of Surgery and Anatomy, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil.
Capellini
Verena Kise
VK
Celotto
Andrea Carla
AC
Carlotti
Carlos Gilberto
CG
Rodrigues
Alfredo José
AJ
Reis
Graziela Saraiva
GS
Augusto
Viviane dos Santos
Vdos S
Evora
Paulo Roberto Barbosa
PR
D001026:Coronary Artery Bypass; D042783:Endothelial Cells / Q000201:enzymology; D006801:Humans; D007150:Immunohistochemistry; D032389:Myocytes, Smooth Muscle / Q000201:enzymology; D052248:Nitric Oxide Synthase Type I / Q000032:analysis*; D052247:Nitric Oxide Synthase Type II / Q000032:analysis*; D052250:Nitric Oxide Synthase Type III / Q000032:analysis*; D011312:Pressure; D012501:Saphenous Vein / Q000201:enzymology* / Q000601:surgery; D020858:Tissue and Organ Harvesting
C496320:NOS1 protein, human; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III