Ex vivo lung perfusion (EVLP) provides the ability to evaluate donor lungs before transplantation. Yet, limited prospective clinical data exist with regard to its potential to recondition unacceptable donor lungs. This paper summarizes the results of a prospective study of lung transplantation using only initially unacceptable donor lungs, which were improved by EVLP for 2–4 h. From March 2010–June 2011, 13 lungs were evaluated ex vivo. Median donor PaO₂ at FiO₂1.0/PEEP5 was 216 mmHg (range 133–271). Four lungs, all with trauma history, showed no improvement and were discarded. Nine lungs improved to a ΔPO₂ higher than 350 mmHg. Median PvO₂ at final assessment in these lungs was 466 mmHg (range 434–525). These lungs were transplanted with a median total ischemic time of 577 min (range 486–678). None of the patients developed primary graft dysfunction grades 2 or 3 within 72 h after transplantation. One patient with secondary pulmonary hypertension was left on a planned prolonged extracorporeal membrane oxygenation postoperatively. Median intubation time was 2 days. Thirty-day mortality was 0%. During the observation period, 119 patients received standard lung transplantation with comparable perioperative outcome. EVLP has a significant potential to improve the quality of otherwise unacceptable donor lungs.

Aims: Radiation-induced normal tissue toxicity often precludes the application of curative radiation doses. Here we investigated the therapeutic potential of Ccl2 signaling inhibition to protect normal lung tissue from radiotherapy (RT)-induced injury. Results: RT-induced vascular dysfunction and associated adverse effects can be efficiently antagonized by inhibition of Ccl2 signaling using either the selective Ccl2 inhibitor bindarit (BIN) or mice deficient for the main Ccl2 receptor CCR2 (KO). BIN-treatment efficiently counteracted the RT-induced expression of Ccl2, normalized endothelial cell (EC) morphology and vascular function and limited lung inflammation and metastasis early after irradiation (acute effects). A similar protection of the vascular compartment was detected by loss of Ccl2 signaling in lungs of CCR2-KO mice. Long-term Ccl2 signaling inhibition also significantly limited EC loss and accompanied fibrosis progression as adverse late effect. With respect to the human situation, we further confirmed that Ccl2 secreted by RT-induced senescent epithelial cells resulted in the activation of normally quiescent but DNA-damaged EC finally leading to endothelial cell loss in ex vivo cultured human normal lung tissue. Innovation: Abrogation of certain aspects of the secretome of irradiated resident lung cells, in particular signaling inhibition of the senescence associated secretory phenotype (SASP)-factor Ccl2 secreted predominantly by RT-induced senescent epithelial cells resulted in protection of the endothelial compartment. Conclusions: Radioprotection of the normal tissue via Ccl2 signaling inhibition without simultaneous protection or preferable radiosensitization of tumor tissue might improve local tumor control and survival, because higher doses of radiation could be used.

Human lungs bear their own reservoir of endogenous mesenchymal stem cells (MSCs). Although described as located perivascular, the cellular identity of primary lung MSCs remains elusive. Here we investigated the vascular nature of lung-resident MSCs (LR-MSCs) using healthy human lung tissue. LR-MSCs predominately reside within the vascular stem cell niche, the so-called vasculogenic zone of adult lung arteries. Primary LR-MSCs isolated from normal human lung tissue showed typical MSC characteristics in vitro and were phenotypically and functionally indistinguishable from MSCs derived from the vascular wall of adult human blood vessels (VW-MSCs). Moreover, LR-MSCs expressed the VW-MSC-specific HOX code a characteristic to discriminate VW-MSCs from phenotypical similar cells. Thus, LR-MSC should be considered as VW-MSCs. Immunofluorescent analyses of non-small lung cancer (NSCLC) specimen further confirmed the vascular adventitia as stem cell niche for LR-MSCs, and revealed their mobilization and activation in NSCLC progression. These findings have implications for understanding the role of MSC in normal lung physiology and pulmonary diseases, as well as for the rational design of additional therapeutic approaches.

Lobar lung transplantation is used mainly for urgent small recipients who are less likely to obtain size matched lungs in due time. Only limited numbers have been published, and we herewith report the largest series of lobar-LuTX. We analyzed our LuTX database from 1/2001 to 12/2012 and compared the outcome of lobar-LuTX recipients with those receiving standard LuTX. Seven hundred and seventy-eighty LuTX (group 1) were performed either in standard technique by implanting the whole lungs (n = 539) or with downsizing by wedge resection of the right middle lobe and/or the left lingula (n = 239). One hundred and thirty-eight LuTX were performed in lobar technique (group 2) to overcome more pronounced size discrepancies. Patients in group 1 had a different spectrum of diagnoses and were less frequently bridged to LuTX (P < 0.001). Intubation time, ICU stay, and hospital stay were shorter in group 1 (P < 0.001). One-year survival was 84.8% vs. 65.1%, and 5-years survival 69.9% vs. 54.9% (P < 0.001). In multivariate analyzes, procedure, diagnosis, and pre-operative bridging were shown to be significant prognostic factors in survival. Early postoperative outcome in Lobar LuTX was significantly inferior to standard LuTX recipients. However, survival rates of successfully dismissed patients were comparable with standard LuTX (P = 0.168); thereby, Lobar-LuTX remains an important option in the management of urgent small recipients.