Morphological, immunohistochemical and biochemical effects of non-pulsatile ex vivo perfusion with crescent pressures in human saphenous veins.
OBJECTIVE
On the average, 15% to 25% of peripheral grafts and 10% to 30% of coronary grafts fail within 5 years. Changes in mechanical forces to which the vein is subjected could be an explanation for this phenomenon. We submitted human saphenous vein segments to non-pulsatile ex vivo perfusion with crescent pressures and evaluated morphology, nitric oxide synthase immunohistochemical expression; tissue levels of nitrite/nitrate and oxidative stress products.


METHODS
Intact segments of human saphenous veins were obtained from 30 patients submitted to elective coronary artery bypass graft surgery. Ex vivo perfusion was performed during 3 hours, using oxygenated Krebs solution, flow of 100 mL/min and pressures of 0, 50, 100, 200 and 300 mmHg, defining five groups.


RESULTS
Optical microscopy showed that veins of groups perfused with 200 and 300 mmHg presented increased luminal area and endothelial denuding. Electron microscopy transmission showed alterations in veins perfused with 200 and 300 mmHg. Immunohistochemical expression of the three nitric oxide synthase isoforms was observed in all vein layers, without significant difference among groups. Tissue levels of nitrite/nitrate were not significantly different among distinctive perfusion. Nitrotyrosine was not immunohistochemically expressed in all veins and malondialdehyde tissue levels were not different among groups.


CONCLUSIONS
Non-pulsatile ex vivo perfusion during 3h caused morphological alterations in human saphenous veins (HSVs), which were not accompanied by immunohistochemical and biochemical alterations. Even with mechanical lesions, HSVs maintained the ability of express nitric oxide synthase (NOS) and release nitric oxide.
Laboratory of Endothelial Function, Department of Surgery and Anatomy, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto/São Paulo, Brazil - prbevora@fmrp.usp.br.
M B
MB
Dalio
L F
LF
Tirapelli
F
F
Viaro
E E
EE
Joviliano
A C
AC
Celotto
V K
VK
Capellini
P R
PR
Evora
D000368:Aged; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D008315:Malondialdehyde / Q000032:analysis; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D009566:Nitrates / Q000032:analysis; D019001:Nitric Oxide Synthase / Q000032:analysis*; D052248:Nitric Oxide Synthase Type I / Q000032:analysis; D052247:Nitric Oxide Synthase Type II / Q000032:analysis; D052250:Nitric Oxide Synthase Type III / Q000032:analysis; D009573:Nitrites / Q000032:analysis; D018384:Oxidative Stress; D010477:Perfusion / Q000379:methods*; D011312:Pressure; D012501:Saphenous Vein / Q000201:enzymology* / Q000648:ultrastructure*; D013314:Stress, Mechanical; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis
D009566:Nitrates; D009573:Nitrites; C002744:3-nitrotyrosine; D014443:Tyrosine; D008315:Malondialdehyde; C496320:NOS1 protein, human; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III