Crucial role for neuronal nitric oxide synthase in early microcirculatory derangement and recipient survival following murine pancreas transplantation.
OBJECTIVE
Aim of this study was to identify the nitric oxide synthase (NOS) isoform involved in early microcirculatory derangements following solid organ transplantation.


BACKGROUND
Tetrahydrobiopterin donor treatment has been shown to specifically attenuate these derangements following pancreas transplantation, and tetrahydrobiopterin-mediated protective effects to rely on its NOS-cofactor activity, rather than on its antioxidant capacity. However, the NOS-isoform mainly involved in this process has still to be defined.


METHODS
Using a murine pancreas transplantation model, grafts lacking one of the three NOS-isoforms were compared to grafts from wild-type controls. Donors were treated with either tetrahydrobiopterin or remained untreated. All grafts were subjected to 16 h cold ischemia time and transplanted into wild-type recipients. Following 4 h graft reperfusion, microcirculation was analysed by confocal intravital fluorescence microscopy. Recipient survival was monitored for 50 days.


RESULTS
Transplantation of the pancreas from untreated wild-type donor mice resulted in microcirculatory damage of the transplanted graft and no recipient survived more than 72 h. Transplanting grafts from untreated donor mice lacking either endothelial or inducible NOS led to similar outcomes. In contrast, donor treatment with tetrahydrobiopterin prevented microcirculatory breakdown enabling long-term survival. Sole exception was transplantation of grafts from untreated donor mice lacking neuronal NOS. It resulted in intact microvascular structure and long-term recipient survival, either if donor mice were untreated or treated with tetrahydrobiopterin.


CONCLUSIONS
We demonstrate for the first time the crucial involvement of neuronal NOS in early microcirculatory derangements following solid organ transplantation. In this model, protective effects of tetrahydrobiopterin are mediated by targeting this isoform.
Center of Operative Medicine, Department of Visceral, Transplant and Thoracic Surgery, Innsbruck Medical University, Innsbruck, Austria; Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria.
Benno
B
Cardini
Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria.
Katrin
K
Watschinger
Department of Anaesthesiology and Critical Care Medicine, Innsbruck Medical University, Innsbruck, Austria.
Martin
M
Hermann
Institute of Pathology, St. Vinzenz Krankenhaus, Zams, Austria.
Peter
P
Obrist
Center of Operative Medicine, Department of Visceral, Transplant and Thoracic Surgery, Innsbruck Medical University, Innsbruck, Austria.
Rupert
R
Oberhuber
Center of Operative Medicine, Department of Visceral, Transplant and Thoracic Surgery, Innsbruck Medical University, Innsbruck, Austria; Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
Gerald
G
Brandacher
Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
Surawee
S
Chuaiphichai
Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
Keith M
KM
Channon
Center of Operative Medicine, Department of Visceral, Transplant and Thoracic Surgery, Innsbruck Medical University, Innsbruck, Austria.
Johann
J
Pratschke
Center of Operative Medicine, Department of Visceral, Transplant and Thoracic Surgery, Innsbruck Medical University, Innsbruck, Austria.
Manuel
M
Maglione
Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria.
Ernst R
ER
Werner
D000818:Animals; D001708:Biopterins / Q000031:analogs & derivatives / Q000494:pharmacology; D003067:Coenzymes / Q000494:pharmacology; D050377:Cold Ischemia; D015870:Gene Expression; D006085:Graft Survival / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009569:Nitric Oxide / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000172:deficiency / Q000235:genetics*; D052247:Nitric Oxide Synthase Type II / Q000172:deficiency / Q000235:genetics; D052250:Nitric Oxide Synthase Type III / Q000172:deficiency / Q000235:genetics; D010179:Pancreas / Q000098:blood supply / Q000187:drug effects / Q000201:enzymology* / Q000601:surgery; D016035:Pancreas Transplantation; D015427:Reperfusion Injury / Q000517:prevention & control*
D003067:Coenzymes; D001708:Biopterins; D009569:Nitric Oxide; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496321:Nos1 protein, mouse; C496317:Nos2 protein, mouse; C496315:Nos3 protein, mouse; C003402:sapropterin