MMP9 and hepatopulmonary syndrome: Interestingly, the present work highlights that already after a relatively short I/R period an acute distant organ damage occurs and that the lung is the first organ involved, suggesting that the increase in lung MMP-9 activity may represent a key and early event involved in the pathogenesis of hepatopulmonary syndrome, whereas kidney injury may occur later and cardiac alterations may be observed only after a period of reperfusion longer than 1 hour [32].