Prostanoid release after lung transplantation.
BACKGROUND
Increased pulmonary vascular resistance is frequently seen after lung transplantation. Thromboxane A2 is a potent vasoconstrictor of pulmonary arteries. Thromboxane-elicited vasoconstriction can ben counteracted by prostacyclin. The effects of lung transplantation on the biosynthesis of these substances were investigated.


METHODS
Pulmonary artery flush perfusion with a low-potassium dextran glucose solution was performed in six donor pigs. After a 24-hour storage period, the left lung was transplanted into a recipient, followed by right pneumonectomy, making the recipient's survival entirely dependent on the transplanted lung. A sham operation (bilateral thoracotomy, right pneumonectomy) ws done in six pigs. the urine contents of the stable thromboxane A2 metabolite 2,3-dinor-thromboxane B2 and the stable prostacyclin metabolite 2,3-dinor-6-keto-protaglandin F1 alpha were measured with a gas chromatography-mass spectrometry method.


RESULTS
One to four hours after reperfusion, thromboxane A2 production reached its maximum in both groups: it ws fivefold the basal value in the transplanted group, but only twofold in the sham-operated group, the difference being significant (p < 0.005). Twenty to twenty-four hours after reperfusion, thromboxane A2 production had stabilized at about twofold the basal value in both the transplanted and in the sham-operated group. Four to eight hours after reperfusion, prostacyclin production reached 15 times the basal value in the transplanted group and twofold in the sham-operated group, the difference being significant (p < 0.05). Twenty to twenty-four hours after reperfusion, prostacyclin production was 18-fold the basal value in the transplanted group and sevenfold in the sham-operated group. No correlation was found between the thromboxane or prostacyclin production and the pulmonary vascular resistance or the mean pulmonary arterial pressure.


CONCLUSIONS
The thromboxane A2 production increased fivefold after lung transplantation, with a concomitant 15-fold increase in prostacyclin synthesis, which might have counteracted the vasoconstrictor effect of thromboxane.
Departmentof Cardiothoracic Surgery, University Hospital, Lund, Sweden.
P O
PO
Kimblad
K
K
Gréen
T
T
Sjöberg
S
S
Steen
D015121:6-Ketoprostaglandin F1 alpha / Q000031:analogs & derivatives / Q000652:urine; D000818:Animals; D011464:Epoprostenol / Q000096:biosynthesis*; D008401:Gas Chromatography-Mass Spectrometry; D016040:Lung Transplantation / Q000502:physiology*; D011651:Pulmonary Artery / Q000502:physiology; D013552:Swine; D013928:Thromboxane A2 / Q000096:biosynthesis*; D013929:Thromboxane B2 / Q000031:analogs & derivatives / Q000652:urine; D013997:Time Factors; D014655:Vascular Resistance
D013929:Thromboxane B2; D013928:Thromboxane A2; D015121:6-Ketoprostaglandin F1 alpha; C028965:2,3-dinor-thromboxane B2; C028290:2,3-dinor-6-ketoprostaglandin F1alpha; D011464:Epoprostenol