Matrix metalloproteinases correlate with alveolar-capillary permeability alteration in lung: Ischemia-reperfusion injury

Background. Matrix metalloproteinases (MMPs) are able to degrade the endoth elial basal lamina and increase vascular permeability, Methods, In a porcine model of isolated-reperfused lung, we studied the alv eolar-capillary permeability and the zymographic expression of MMP-9 and MM P-2 in the bronchoalveolar lavage fluid of lungs submitted ex vivo to ische mia in three preservation solutions [modified Euro-Collins (EC), low-potass ium-dextran, modified-blood]. Twenty-two pigs were randomly divided into th ree groups according to the preservation solution used. One lung of each pi g was rapidly reperfused and analyzed (control lung) although the other lun g was reperfused and analyzed after 8 hr of ischemia (ischemic lung). Results. Alveolar-capillary permeability, evaluated by the transferrin leak index, was increased after 8 hr of ischemia compared with controls in the three groups, but was significantly higher in the modified EC group. In the EC group, after 8 hr of ischemia, both proMMP-9 and MMP-9 increased signif icantly (8.8- and 22-fold, respectively) compared with controls and this in crease correlated with the transferrin leak index. Neither proMMP-9 nor MMP -9 increased with the other two preservation solutions. The MMP-2 increase after ischemia was smaller and was also restricted to the EC group. Conclusion. MMP expression is enhanced during lung ischemia-reperfusion, es pecially in the presence of EC and this phenomenon correlates with the alte ration of alveolar-capillary permeability.