Paradoxical cholinergic and purinergic vascular reactivity of rabbit thoracic aorta cold-stored in University of Wisconsin solution.
Endothelial dysfunction has been reported in donor blood vessels destined for organ transplantation following cold-storage preservation with University of Wisconsin solution (UW). This was investigated in the present work. Segments of rabbit thoracic aorta were mounted on isometric fine-wire myographs at 37 degrees C and gassed with 95% O2/5% CO2. Concentration-dependent vasodilatations to acetylcholine and adenosine-5'-triphosphate (ATP) were obtained in freshly-harvested rabbit aortic rings, with and without the endothelium, and after 8 days of cold-storage, at 4 degrees C, in either UW, Krebs-Bülbring buffer (KBB) or saline. The action of the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) (100 microM) was evaluated upon the concentration-response curves to determine whether nitric oxide (NO) exerted any modulatory actions. Endothelium-dependent, NO-mediated responses to acetylcholine were unaltered after eight days of storage in UW, reduced after storage in KBB and absent after removal of the vascular endothelium, saline storage or after testing in the presence of L-NAME, suggesting improved NO-mediated endothelial function with the use of UW. Structural preservation was also confirmed using scanning electron microscopy. In contrast, endothelium-dependent responses to ATP were unchanged after eight days of storage in KBB but were reduced after storage in UW and saline, suggesting purinergic (ATP) endothelial dysfunction after storage in UW. L-NAME markedly reduced vasodilatation to ATP in freshly harvested rings and after eight days of storage in KBB. This reduction was statistically significant (P < 0.05, Student's two tailed, unpaired t-test) at -log (M) ATP concentrations of 5.5, 5.0, 4.5, 4.0 and 3.5. NO-dependent vasodilatation to ATP was not attenuated by L-NAME in UW-stored rings. Eight days' UW-storage of rabbit thoracic aortic rings appeared to have differential and paradoxical effects upon NO-dependent vasodilatation to acetylcholine and ATP. Morphological observations using electron microscopy suggested that UW preserved the vascular endothelium and this was verified by retained vascular reactivity of endothelium-dependent vasodilatations to acetylcholine. UW-storage however, significantly reduced endothelium-dependent relaxation to ATP thereby suggesting that P2Y-purinoceptors, which are located on the vascular endothelium, may be more susceptible to biodegradation than cholinergic receptors and may be responsible for endothelial dysfunction following transplantation.
Department of Surgery, King's College School of Medicine and Dentistry, The Rayne Institute, London, UK. barry.alexander@kcl.ac.uk
B
B
Alexander
J V
JV
Gryf-Lowczowski
D
D
Sherlock
J
J
Salisbury
I S
IS
Benjamin
D000109:Acetylcholine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D003080:Cold Temperature; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000502:physiology; D008297:Male; D009569:Nitric Oxide / Q000502:physiology; D009926:Organ Preservation / Q000379:methods; D019188:Organ Preservation Solutions; D011817:Rabbits; D011950:Receptors, Cholinergic / Q000378:metabolism*; D011983:Receptors, Purinergic / Q000378:metabolism*; D014664:Vasodilation / Q000187:drug effects
D019188:Organ Preservation Solutions; D011950:Receptors, Cholinergic; D011983:Receptors, Purinergic; D009569:Nitric Oxide; D000255:Adenosine Triphosphate; D000109:Acetylcholine