RESEARCH ARTICLE Transbronchial administration of adenoviral-mediated interleukin-10 gene to the donor improves function in a pig lung transplant model S Martins 1 , M de Perrot 1 , Y Imai 1 , M Yamane 1 , SM Quadri 1 , L Segall 1 , A Dutly 1 , S Sakiyama 1 , A Chaparro 1 , BL Davidson 2 , TK Waddell 1 , M Liu 1 and S Keshavjee 1 1 Thoracic SurgeryResearch Laboratory, Toronto General Hospital Research Institute, University Health Network, University of Toronto, Toronto, ON, Canada; and 2 The Gene Transfer Vector Core, Department of Medicine, University of Iowa, Iowa, USA Interleukin-10 (IL-10) gene transfection of donor lungs prior to transplantation is an attractive strategy to reduce ischemia–reperfusion induced lung injury. However, experi- mental data with gene therapy in large animal models of lung transplantation are generally lacking. We have developed a simple clinically applicable technique for adenoviral- mediated gene delivery of human IL-10 to the lung of large animals that provides homogenous gene expression after 12–24 h of transfection. Using this technique of gene delivery, we have studied the dynamics of adenoviral gene delivery to the lung in the setting of lung transplantation. Although there is a persistent inflammatory response to the adenoviral vector, we achieved significant expression of human IL-10 in lung tissue before lung retrieval to obviate the deleterious impact of the adenoviral vector on the donor lung. The administration of adenoviral-mediated human IL-10 to the donor lung reduced ischemia–reperfusion injury and improved graft function after lung transplantation in this pig lung transplantation model. Transfection of adenoviral- mediated human IL-10 to the donor lung prevented the release of inflammatory cytokines such as IL-6 in lung tissue and plasma. We have demonstrated that IL-10 gene therapy has significant potential to prevent or treat the inflammatory response associated with ischemia–reperfusion injury in lung transplantation. In the future, IL-10 gene therapy could also be used for immunomodulation or tolerance induction. Gene Therapy (2004) 11, 1786–1796. doi:10.1038/ sj.gt.3302357; Published online 7 October 2004 Keywords: adenovirus; interleukin-10; ischemia–reperfusion injury; cytokines; lung transplantation Introduction Lung transplantation has enjoyed increasing success and has become the mainstay of therapy for patients with a variety of end-stage lung diseases. Over the past 10 years, the number of recipients on the waiting list has been progressively increasing and now far exceeds the number of organs available. 1 Consequently, the median waiting time for lung transplantation has nearly doubled in the United States, and some centers in Europe have reported that up to 50% of patients awaiting lung transplantation die on the waiting list. 2 The persistent shortage of lung donors has led to increasing interest in re-evaluating the existing lung donor pool. Traditionally, the rigid selection criteria that were developed in the early clinical experience limited clinicians to using 10% or less of the donor pool. Over the years, the donor selection criteria have been expanded to the use of ‘nonideal’ lung donors. 3–6 However, this strategy can contribute to an increased risk of immediate graft dysfunction that in turn may lead to enhanced rejection and impaired long-term graft function. 3,7–9 Hence, the development of new strategies to repair and improve the quality of donor lungs could have a tremendous impact on the number of transplants per- formed as well as on the outcome after transplantation. Genetic modification of donor organs using gene therapeutic approaches is one such novel and promising strategy. The utilization of gene therapy in the trans- plantation setting is facilitated by the fact that the immunosuppressive therapy used to prevent graft rejection allows more effective and prolonged transfec- tion. 10 This strategy, however, is hindered by the poor transfection rate obtainable during the period of cold temperature required to preserve the organ, and by the drawback of unnecessarily transfecting other organs if the gene is delivered systemically instead of locally. 11,12 To overcome these problems, in previous experiments we delivered the gene to the donor lung through the transtracheal route before retrieving and cooling the lungs to 41C. 13 This technique appears to be superior to other techniques of gene delivery and avoids unneces- sary transfection of other organs such as the heart, liver, or kidneys. 12,13 Cytokines have been shown to play a critical role in modulating inflammatory processes and in enhancing cellular infiltration in transplanted organs. In human lung transplantation, we and others have observed that Received 4 January 2004; accepted 22 July 2004; published online 7 October 2004 Correspondence: Dr S Keshavjee, Thoracic Surgery Research Laboratory, Toronto General Hospital, 200 Elizabeth Street, EN 10-224, Toronto, Ontario, Canada M5G 2C4 Gene Therapy (2004) 11, 1786–1796 & 2004 Nature Publishing Group All rights reserved 0969-7128/04 $30.00 www.nature.com/gt