A standardized model of brain death, donor treatment, and lung transplantation for studies on organ preservation and reconditioning

Abstract

BackgroundWe set a model of brain death, donor management, and lung transplantation for studies on lung preservation and reconditioning before transplantation.MethodsTen pigs (39.7 ± 5.9 Kg) were investigated. Five animals underwent brain death and were treated as organ donors; the lungs were then procured and cold stored (Ischemia). Five recipients underwent left lung transplantation and post-reperfusion follow-up (Graft). Cardiorespiratory and metabolic parameters were collected. Lung gene expression of cytokines (tumor necrosis factor alpha (TNFα), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interferon gamma (IFNγ), high mobility group box-1 (HMGB-1)), chemokines (chemokine CC motif ligand-2 (CCL2-MCP-1), chemokine CXC motif ligand-10 (CXCL-10), interleukin-8 (IL-8)), and endothelial activation markers (endothelin-1 (EDN-1), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), selectin-E (SELE)) was assessed by real-time polymerase chain reaction (PCR).ResultsTachycardia and hypertension occurred during brain death induction; cardiac output rose, systemic vascular resistance dropped (P < 0.05), and diabetes insipidus occurred. Lung-protective ventilation strategy was applied: 9 h after brain death induction, PaO2 was 192 ± 12 mmHg at positive end-expiratory pressure (PEEP) 8.0 ± 1.8 cmH2O and FiO2 of 40%; wet-to-dry ratio (W/D) was 5.8 ± 0.5, and extravascular lung water (EVLW) was 359 ± 80 mL. Procured lungs were cold-stored for 471 ± 24 min (Ischemia) at the end of which W/D was 6.1 ± 0.9. Left lungs were transplanted and reperfused (warm ischemia 98 ± 14 min). Six hours after controlled reperfusion, PaO2 was 192 ± 23 mmHg (PEEP 8.7 ± 1.5 cmH2O, FiO2 40%), W/D was 5.6 ± 0.4, and EVLW was 366 ± 117 mL. Levels of IL-8 rose at the end of donor management (BD, P < 0.05); CCL2-MCP-1, IL-8, HMGB-1, and SELE were significantly altered after reperfusion (Graft, P < 0.05).ConclusionsWe have set a standardized, reproducible pig model resembling the entire process of organ donation that may be used as a platform to test in vivo and ex vivo strategies of donor lung optimization before transplantation.Electronic supplementary materialThe online version of this article (doi:10.1186/2197-425X-2-12) contains supplementary material, which is available to authorized users.

Mechanical versus humoral determinants of brain death-induced lung injury

“…Transcription of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) is induced by TNF-α and IL-1β [ 50 ]. The expressions of ICAM-1 and VCAM-1 have been reported to be increased in toxic and BD-induced models of acute lung injury [ 48 , 49 ] but remained unchanged in the present study as reported by other authors [ 48 ]. The activation of apoptosis suggested by the increased lung apoptotic rate measured by TUNEL immunochemistry in the present study is also consistent with previous reports [ 51 ] and seems to be closely related to the activation of inflammatory processes.…”

“…Although IL-1β and TNF-α are physiologic stimuli for the synthesis of IL-6, we failed to find altered expression for them after brain death. Several studies have shown elevated lung TNF-α and IL-1β expression [ 42 , 47 , 48 ] or no significant change in lung tissue TNF-α and IL-1β expression [ 49 ], suggesting variable expression of these cytokines after brain death. Lung tissue expression in IL-6 and pro-inflammatory IL-6/IL-10 returned to normal level five hours after brain death, suggesting their implication as an early inflammatory response to hemodynamic stress.…”

Inhibition of B cell–dependent lymphoid follicle formation prevents lymphocytic bronchiolitis after lung transplantation

“…These anatomical differences constitute a limit to a direct extrapolation of murine models of chronic lung disease, including ours, to the human situation. Eventually, alternative animal models, e.g., pigs or ferrets, will unravel the role of basal progenitor cells, as these species also contain club cells and bronchial progenitor cell populations in the distal airways (53,54).…”

Lung Transplantation From Controlled and Uncontrolled Donation After Circulatory Death (DCD) Donors With Long Ischemic Times Managed by Simple Normothermic Ventilation and Ex-Vivo Lung Perfusion Assessment

“…WLST is also allowed by Italian law but has not become common practice yet and has been only recently codified. After a long pre-clinical phase ( 5 , 6 , 7 ), we refined an original two-steps protocol to manage lungs from DCD donors to overcome the long acirculatory period ( 8 ). First, by leveraging the possibility of dissociating ischemia from hypoxia, we adopted an open lung strategy for in-situ lung preservation even for prolonged periods, without topical cooling.…”