α1-Antitrypsin inhibits ischemia reperfusion-induced lung injury by reducing inflammatory response and cell death.

Background: Pulmonary ischemia-reperfusion (IR)-induced lung injury is a severe complication that increases the likelihood of primary graft dysfunction and early death after lung transplantation. Inflammatory cytokine release and cell death play a critical role in the development of IR-induced lung injury. α1-Antitrypsin (A1AT) is a protease inhibitor clinically used for the treatment of A1AT-deficiency emphysema. On the basis of a literature review, we hypothesize that A1AT may have the potential to reduce IR-induced lung injury through its anti-inflammatory and anti-apoptotic effects.

Methods: A human pulmonary cell culture model was used to simulate IR processes in lung transplantation. Effects of A1AT on cell death and cytokine production were examined. A rat pulmonary IR model, in which the left pulmonary hilum was clamped for 90 minutes, followed by reperfusion for 2 hours, was used to determine the effects of A1AT on acute lung injury, function, cell death, and inflammatory response.

Results: A1AT significantly inhibited cell death and inflammatory cytokine release dose-dependently in vitro and significantly improved lung oxygenation and lung mechanics and reduced pulmonary edema in vivo. Moreover, A1AT inhibited neutrophil infiltration in the lung and reduced cell death and significantly reduced IR-induced inflammatory mediators in plasma, including interleukin (IL)-1α, IL-4, IL-12p70, monocyte chemotactic protein 1, and tumor necrosis factor-α.

Conclusions: Considering its current clinical use, our findings indicate that administration of A1AT may be an effective and safe therapy for the treatment of IR injury in human lung transplantation.