Effect of perfusion and preservation on IL1-beta, IL-6, and IL-10 production in murine lung.

We evaluated the production of the interleukins (ILs) IL-1beta, IL-6, and IL-10 in both the vasculature and pulmonary tissue before and after 24 h of lung preservation. The cardiopulmonary blocs of 21 Balb-c mice were divided into three study groups (7 mice/group) and were flushed through the pulmonary artery with Krebs-Henseleit buffer (K-Hb) at 4 degrees C at a rate of 0.2 mL/min as follows: Group 1, lung washout: lungs were flushed until pulmonary effluent was clear. Group 2, perfusion: After lungs were flushed until pulmonary effluent was clear, lungs were perfused during 30 min. Group 3, preservation: Lungs were flushed until pulmonary effluent was clear, and the cardiopulmonary bloc was preserved immersed into (K-Hb) at 4 degrees C. After 24 h of preservation, lungs were reperfused during 30 min. In all study groups the caudal lobe from the left lung was taken for microscopical study; all other lobes were homogenized with (K-Hb) and the supernatant was obtained. IL-1beta, IL-6, and IL-10 production in lung effluents (washout, perfusion, and reperfusion) and in lung tissue were measured by enzyme-linked immunosorbent assay (ELISA). In the lung effluent, there was no statistical difference between IL-1beta and IL-6 concentrations. In all study groups, IL-10 production was significantly higher than IL-1beta and IL-6 levels. IL-10 level was lowest in the 24-h preservation group when it was compared to the other groups. In group 1, there was a negative correlation (r = -.599, p < .05) between IL-1beta and IL-10. In pulmonary tissue, IL-1beta was higher in group 2 when compared to groups 1 (p = .001) and 3 (p = .002), and it was significantly lower in group 3. IL-10 was lower in group 1 when compared to groups 2 (p = .001) and 3 (p = .004). In groups 1 and 2, IL-1beta was significantly higher than IL-6 and IL-10. In group 3, IL-10 was higher than IL-1beta (p = .0001) and IL-6 (p = .0001). Correlation of effluent/tissue index with histological findings showed a negative correlation between IL-10 effluent/tissue relation and inflammation (r = -.68, p < .01). In conclusion, the main cytokine found in lung effluents was IL-10, followed by IL-6 and IL-1beta. On the other hand, cytokine concentration in lung tissue homogenates was mainly due to the presence of IL-1beta. However, this cytokine shows a significant reduction in lung tissue after prolonged preservation.

Effect of prostaglandin E2 on the tracheobronchial distribution of lung preservation perfusate.

Complete lung preservation requires the perfusate to reach the cell it intends to protect; this is directly related to the distribution of the preserving solution throughout the lung vasculature. Several prostanoids are clinically used to enhance lung preservation. We evaluated the effect of prostaglandin E2 (PGE2) on the distribution of lung perfusate throughout tracheobronchial tissue. Fourteen pulmonary blocks were procured from an equal number of dogs and divided according to whether or not they had previously received a PGE2 infusion. All lung blocks were perfused with a glucose-insulin-potassium solution, and distribution within the lung parenchyma and tracheobronchial tissue was measured using the flow reference technique and gadolinium-153-labeled microspheres. Once perfusion had taken place, samples of lung parenchyma, tracheobronchial tissue, and flow reference were measured for radioactivity, and flow was calculated per 100 g tissue. Animals receiving PGE2 had an expected 38% decrease in systemic arterial pressure; the duration of infusion of lung perfusate during procurement was shorter in those animals receiving PGE2 (5.75 +/- 0.3 min, vs. no PGE2 8.9 +/- 1.2 min; p < .05). Perfusate flow of bronchial mucosa and cartilage increased by two to three times with the infusion of PGE2 (p < .01). Perfusate flow to lobar bronchus or lung parenchyma was similar in both groups. Flow within the lung parenchyma did not differ statistically when compared to its lobar distribution. In conclusion, PGE2-treated animals had a two- to threefold increase in perfusate flow to mainstem bronchi (including mucosa); these findings to some extent support the rationale for utilizing prostanoids in order to enhance lung preservation in clinical lung transplantation.

Plasma thromboxane B2 concentrations and pulmonary vascular resistance during lung reperfusion.

The purpose of this study was to measure the behavior of plasmatic thromboxane B2 (pITxB2) after reperfusion of a glucose-insulin-potassium preserved lung. Seven adult mongrel dogs underwent a left lung allotransplantation. Hemodynamic changes including pulmonary artery pressure and cardiac output were measured. Pulmonary artery vascular resistance, systemic resistance, arterio-venous oxygen difference, and shunt were calculated. Immunoreactive arterial and venous plasma thromboxane B2 concentrations were measured at 0 (basal), 60, 120, and 180 min after reperfusion. Hemodynamic measurements were made after 5 min of occlusion of the right pulmonary artery and ventilation with 100% oxygen. Prepreservation, pre-reperfusion, and posttransplant lung weights were obtained. All animals survived the procedure. Ischemic time was 14.72 (+/-0.31) h. Cardiac output, systemic arterial pressure, and arterio-venous oxygen difference decreased while systemic vascular resistance, pulmonary vascular resistance, and shunt increased during the study. Mean pulmonary artery pressure correlated with pulmonary vascular resistance (p < .01). Oxygen tension diminished significantly at 180 min after reperfusion. Mean basal pulmonary arterial TxB2 was 3589 (+/-424) pg/ml; mean plasma pulmonary venous TxB2 was 6578 (+/-1571) pg/ml. Pulmonary arterial to venous TxB2 ratio (a/vTxB2) increased from 0.70 at basal measurement to 0.83 at 60 min, and 0.99 at 120 and 180 min after reperfusion (p < .05). Pulmonary arterial TxB2 had a positive correlation with mean pulmonary artery pressure (p < .05); also, a/v pITxB2 correlated with pulmonary vascular resistance (r = .616, p < .01). Mean post-reperfusion lung weight increase was 74.88% (45.37 g). In conclusion, pITxB2 a/v ratio ratio increases after reperfusion of a 14-h preserved lung; pulmonary vascular resistance significantly increases after 180 min of reperfusion and correlates with the increase in pITxB2 a/v ratio.