Retention of endothelium-dependent properties in human mammary arteries after cryopreservation.
BACKGROUND
We investigated the effects of cryopreservation and antibiotic treatment on endothelium-dependent vasomotor properties of human internal mammary arteries (IMAs).


METHODS
Sixty IMA specimens from routine coronary artery bypass grafting procedures were randomly assigned to six groups. Group I (controls) were immediately tested after harvest. Remaining groups were prepared according to a stepwise design: group II, 6 hours of warm ischemia; group III, 6 hours of warm ischemia + 24 hours at 4 degrees C (without antibiotics); group IV, 6 hours of warm ischemia + 24 hours of 4 degrees C antibiotic disinfection; group V, 6 hours of warm ischemia + 24 hours at 4 degrees C (without antibiotics) + cryopreservation; and group VI, 6 hours of warm ischemia + 24 hours of 4 degrees C disinfection+cryopreservation. The IMA specimens were cut into rings and the tension of vascular smooth muscle was recorded. The IMA rings were contracted with norepinephrine (3 x 10(-6) mol/L) and tested with cumulative concentrations of acetylcholine (from 1 x 10(-9) to 1 x 10(-5) mol/L), contracted with endothelin-1 (from 1 x 10(-11) to 1 x 10(-6) mol/L), and contracted with the nitric oxide-synthase inhibitor NG-monomethyl-L-arginine (1 x 10(-4) mol/L). Rings were also tested for their capacity to generate 6-keto-prostaglandin F1 (the stable metabolite of prostacyclin), and endothelial cell viability rate was finally evaluated with the trypan blue dye exclusion method.


RESULTS
Our results show that a complete cryopreservation protocol does not significantly modify (p > 0.05) the relaxant activity to acetylcholine in norepinephrine-precontracted IMA rings (controls; 90.2% +/- 4.2% vs group VI, 77.1% +/- 6.2%) or the vasoconstrictor response induced by endothelin-1 (controls, 62.6% +/- 2.8% versus group VI, 73.7% +/- 4.8%) and NG-monomethyl-L-arginine (controls, 22.4% +/- 1.5% versus group VI, 18.9% +/- 1.9%). Furthermore, IMA cryopreservation does not significantly modify (p > 0.05) the endothelial release of prostacyclin either in basal conditions (-20% versus controls) or during pharmacologic intervention with acetylcholine (-18% versus controls), endothelin-1 (-17% versus controls), and NG-monomethyl-L-arginine (-18% versus controls).


CONCLUSIONS
We conclude that the IMA endothelial function does not seem significantly injured by any of the current steps of disinfection and cryopreservation.
Pompilio
G
G
Department of Cardiac Surgery, Italian Homograft Bank, Milan, Italy.
Polvani
G L
GL
Antona
C
C
Rossoni
G
G
Guarino
A
A
Porqueddu
M
M
Buche
M
M
Biglioli
P
P
Sala
A
A
D015121:6-Ketoprostaglandin F1 alpha / Q000378:metabolism; D000109:Acetylcholine / Q000494:pharmacology; D000704:Analysis of Variance; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D015925:Cryopreservation; D004305:Dose-Response Relationship, Drug; D016232:Endothelins / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology*; D006801:Humans; D066298:In Vitro Techniques; D008323:Mammary Arteries / Q000187:drug effects / Q000503:physiopathology*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009638:Norepinephrine / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D019323:omega-N-Methylarginine
D000900:Anti-Bacterial Agents; D016232:Endothelins; D014662:Vasoconstrictor Agents; D019323:omega-N-Methylarginine; D015121:6-Ketoprostaglandin F1 alpha; D001120:Arginine; D019001:Nitric Oxide Synthase; D000109:Acetylcholine; D009638:Norepinephrine