Lung transplantation remains the best treatment option for end-stage lung disease; however, is limited by a shortage of donor grafts. Ex situ lung perfusion, also known as ex vivo lung perfusion, has been shown to allow for the safe evaluation and reconditioning of extended criteria donor lungs, increasing donor utilization. Negative pressure ventilation ex situ lung perfusion has been shown, preclinically, to result in less ventilator-induced lung injury than positive pressure ventilation. Here we demonstrate that, in a single-arm interventional study (ClinicalTrials.gov number NCT03293043) of 12 extended criteria donor human lungs, negative pressure ventilation ex situ lung perfusion allows for preservation and evaluation of donor lungs with all grafts and patients surviving to 30 days and recovered to discharge from hospital. This trial also demonstrates that ex situ lung perfusion is safe and feasible with no patients demonstrating primary graft dysfunction scores grade 3 at 72 h or requiring post-operative extracorporeal membrane oxygenation.

Background: Ex situ heart perfusion (ESHP) preserves the donated heart in a perfused, beating condition preventing cold storage–related ischemia and provides a platform to evaluate myocardial viability during preservation. However, myocardial function declines gradually during ESHP. Extracorporeal circulation systems are associated with the induction of systemic inflammatory and stress responses. Our aim was to evaluate the incidence of inflammation and induction of endoplasmic reticulum stress responses during an extended period of ESHP. Methods: Cardiac function, myocardial tissue injury, markers of inflammation, oxidative stress, and endoplasmic reticulum stress were assessed in healthy pig hearts, perfused for 12 hours either in nonworking mode (non-WM=7) or working mode (WM, n=6). Results: Cardiac function declined during ESHP but was significantly better preserved in the hearts perfused in WM (median 11-hour cardiac index/1-hour cardiac index: WM=27% versus non-WM=9.5%, P =0.022). Myocardial markers of endoplasmic reticulum stress were expressed higher in ESHP hearts compared with in vivo samples. The proinflammatory cytokines and oxidized low-density lipoprotein significantly increased in the perfusate throughout the perfusion in both perfusion groups. The left ventricular expression of the cytokines and malondialdehyde was induced in non-WM, whereas it was not different between WM and in vivo. Conclusions: Myocardial function declines during ESHP regardless of perfusion mode. However, ESHP in WM may lead to superior preservation of myocardial function and viability. Both inflammation and endoplasmic reticulum stress responses are significantly induced during ESHP and may contribute to the myocardial functional decline, representing a potential therapeutic target to improve the clinical donor heart preservation.

Ex vivo lung perfusion (EVLP) protocols generally limit metabolic supplementation to insulin and glucose. We sought to determine whether the addition of total parenteral nutrition (TPN) would improve lung function in EVLP. Ten porcine lungs were perfused using EVLP for 24 hours and supplemented with insulin and glucose. In the treatment group (n = 5), the perfusate was also supplemented with a continuous infusion of TPN containing lipids, amino acids, essential vitamins, and cofactors. Physiologic parameters and perfusate electrolytes were continuously evaluated. Perfusate lactate, lipid and branch chain amino acid (BCAA) concentrations were also analyzed to elucidate how substrates were being utilized over time. Lungs in the TPN group exhibited significantly better oxygenation. Perfusate sodium was more stable in the TPN group. In the control group, free fatty acids (FFA) were quickly depleted, reaching negligible levels early in the perfusion. Alternatively, BCAA in the control group rose continually over the perfusion demonstrating a shift toward proteolysis for energy substrate. In the TPN group, both FFA and BCAA concentrations remained stable at in vivo levels after initial stabilization. TNF‐α concentrations were lower in the TPN group. The addition of TPN in EVLP allows for better electrolyte composition, decreased inflammation, and improved graft performance.

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