Retrograde perfusion in isolated perfused mouse lungs—Feasibility and effects on cytokine levels and pulmonary oedema formation

Abstract

Retrograde lung vascular perfusion can appear in high‐risk surgeries. The present report is the first to study long‐term retrograde perfusion of isolated perfused mouse lungs (IPLs) and to use the tyrosine kinase ephB4 and its ligand ephrinB2 as potential markers for acute lung injury. Mouse lungs were subjected to anterograde or retrograde perfusion with normal‐pressure ventilation (NV) or high‐pressure ventilation (=overventilation, OV) for 4 hours. Outcome parameters were cytokine, ephrinB2 and ephB4 levels in perfusate samples and bronchoalveolar lavage (BAL), and the wet‐to‐dry ratio. Anterograde perfusion was feasible for 4 hours, while lungs receiving retrograde perfusion presented considerable collapse rates. Retrograde perfusion resulted in an increased wet‐to‐dry ratio when combined with high‐pressure ventilation; other physiological parameters were not affected. Cytokine levels in BAL and perfusate, as well as levels of soluble ephB4 in BAL were increased in OV, while soluble ephrinB2 BAL levels were increased in retrograde perfusion. BAL levels of ephrinB2 and ephB4 were also determined in vivo, including mice ventilated for 7 hours with normal‐volume ventilation (NVV) or high‐volume ventilation (HVV) with increased levels of ephB4 in HVV BAL compared to NVV. Retrograde perfusion in IPL is limited as a routine method to investigate effects due to collapse for yet unclear reasons. If successful, retrograde perfusion has an influence on pulmonary oedema formation. In BAL, ephrinB2 seems to be up‐regulated by flow reversal, while ephB4 is a marker for acute lung injury.

Welding Fume Instillation in Isolated Perfused Mouse Lungs—Effects of Zinc- and Copper-Containing Welding Fumes

“…It is possible that the time course of experiments was too short to detect effects on the mRNA expression of PTP1B. EphrinB2 and EphB4 as ligand and consecutive receptors also showed no significant change in expression although ephB4 has been shown to indicate lung injury in mouse IPLs and in vivo [ 26 ]. Differences in those two studies could be due to different infliction of lung injury.…”

Never Change a Flowing System? The Effects of Retrograde Flow on Isolated Perfused Lungs and Vessels

“…In contrast, in our study, all rat lungs lasted until the end of the experiments, although edema formation was visible and indicated by lung weight increases in retrograde perfusion. Similar to mouse IPL, there was edema formation in rat IPL with retrograde perfusion in our study, although no second trigger was necessary in contrast to the additional acute lung injury in mouse IPL [ 5 ]. The reported edema formation could also be due to alterations of NO production described for bovine aortic endothelial cells subjected to 180° flow direction change [ 6 ].…”

“…However retrograde perfusion was performed with increasing flow rates but only for up to 60 min of perfusion and ventilation [ 4 ]. Another study from our laboratory observed pulmonary edema formation in retrogradely perfused mouse IPL for 4 h only in combination with an additional hit like acute lung injury [ 5 ]. Furthermore, retrograde perfusion led in some mouse IPL to termination of the experiments due to sudden massive pulmonary edema formation.…”

“…Based on data from Krabbe and colleagues [ 5 ] and our own preliminary data, the experiments were planned with a statistical power of 80% and an alpha error of 0.05 (corrected for multiple comparisons) in order to detect differences in wet-to-dry ratio greater than 1.25 (G*Power v. 3.1.9.2, Düsseldorf, Germany [ 18 , 19 ]), which resulted in a group size of at least n = 5. Data analysis was performed using SAS 9.4 (SAS Institute Inc., Cary, NC, USA).…”

“…In the lungs, retrograde perfusion of the pulmonary circulation only occurs as a rare ultima ratio therapy of pulmonary embolisms as intraoperative flow reversal to wash out remaining thrombotic material after thrombectomy. In experiments, retrograde lung perfusion was examined in very few experimental studies in rat [ 4 ] and mouse [ 5 ] isolated perfused lungs (IPL) for short periods of time (60 min) and with high failure rates. Interestingly, in retrogradely perfused mouse IPL, a large amount of edema formation occurred when the lungs were also damaged by overventilation [ 5 ].…”