Verapamil used in lung transplantation: could it have a cytoprotective effect during the ischemic phase of pulmonary preservation? Study on alveolar type II cells

It has been shown that Verapamil (V) improves lung preservation, but it is not clear whether the effect is due to vasodilation, with a more homogeneous cooling effect during hypothermic preservation, or a direct cytoprotection. Attempting to verify this, we studied the cellular viability of rats' pneumocytes type II primary cultures separately incubated in the first experiment for 6 hours in Ringer Lactate (RL) +/- V (10 mg/l) at 25 degrees C and at 4 degrees C, and in the second experiment for the same period in RL, EuroCollins (EC) and Collins (CL) solution +/- V (10 mg/l) at 4 degrees C. We analyzed the influence of the drug using two methods: the total protein content in each culture and the metabolic function of the cells using the rate of protein synthesis by means of 35 S methionine uptake assay. All data showed that there were no significant statistical difference (Student t-test, p0.05) in the use of verapamil during alveolar type II cells either in normothermic or hypothermic preservation. Thus we conclude that the protection of this calcium channel blocker during lung preservation is probably due to the effect on pulmonary vessels rather than to a direct cytoprotective effect on the lung cells.