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- Längin, Matthias, et al.
(författare)
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Cold non-ischemic heart preservation with continuous perfusion prevents early graft failure in orthotopic pig-to-baboon xenotransplantation
- 2021
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Ingår i: Xenotransplantation. - : Wiley. - 0908-665X .- 1399-3089. ; 28:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Successful preclinical transplantations of porcine hearts into baboon recipients are required before commencing clinical trials. Despite years of research, over half of the orthotopic cardiac xenografts were lost during the first 48 hours after transplantation, primarily caused by perioperative cardiac xenograft dysfunction (PCXD). To decrease the rate of PCXD, we adopted a preservation technique of cold non-ischemic perfusion for our ongoing pig-to-baboon cardiac xenotransplantation project. Methods: Fourteen orthotopic cardiac xenotransplantation experiments were carried out with genetically modified juvenile pigs (GGTA1- KO/hCD46/hTBM) as donors and captive-bred baboons as recipients. Organ preservation was compared according to the two techniques applied: cold static ischemic cardioplegia (IC; n = 5) and cold non-ischemic continuous perfusion (CP; n = 9) with an oxygenated albumin-containing hyperoncotic cardioplegic solution containing nutrients, erythrocytes and hormones. Prior to surgery, we measured serum levels of preformed anti-non-Gal-antibodies. During surgery, hemodynamic parameters were monitored with transpulmonary thermodilution. Central venous blood gas analyses were taken at regular intervals to estimate oxygen extraction, as well as lactate production. After surgery, we measured troponine T and serum parameters of the recipient’s kidney, liver and coagulation functions. Results: In porcine grafts preserved with IC, we found significantly depressed systolic cardiac function after transplantation which did not recover despite increasing inotropic support. Postoperative oxygen extraction and lactate production were significantly increased. Troponin T, creatinine, aspartate aminotransferase levels were pathologically high, whereas prothrombin ratios were abnormally low. In three of five IC experiments, PCXD developed within 24 hours. By contrast, all nine hearts preserved with CP retained fully preserved systolic function, none showed any signs of PCXD. Oxygen extraction was within normal ranges; serum lactate as well as parameters of organ functions were only mildly elevated. Preformed anti-non-Gal-antibodies were similar in recipients receiving grafts from either IC or CP preservation. Conclusions: While standard ischemic cardioplegia solutions have been used with great success in human allotransplantation over many years, our data indicate that they are insufficient for preservation of porcine hearts transplanted into baboons: Ischemic storage caused severe impairment of cardiac function and decreased tissue oxygen supply, leading to multi-organ failure in more than half of the xenotransplantation experiments. In contrast, cold non-ischemic heart preservation with continuous perfusion reliably prevented early graft failure. Consistent survival in the perioperative phase is a prerequisite for preclinical long-term results after cardiac xenotransplantation.
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| 2. |
- Major, Triin, et al.
(författare)
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Pro-IL-1β Is an Early Prognostic Indicator of Severe Donor Lung Injury During Ex Vivo Lung Perfusion
- 2021
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Ingår i: Transplantation. - 1534-6080. ; 105:4, s. 768-774
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Ex vivo lung perfusion (EVLP) is used to evaluate and recondition extended criteria donor lungs for transplantation. Interleukin-1β (IL-1β) has been identified as a prognostic indicator of nonrecovery during EVLP. This may be an effect of inflammasome activation or cellular necrosis following donation and graft preservation. Delineating the mechanism of IL-1β release is required. METHODS: The inactive intracellular precursor molecule, pro-IL-1β, was characterized along with the pro-IL-1β processing enzyme, caspase-1, in the perfusate of n = 20 human lungs that had undergone EVLP (n = 10 lungs that failed to recover and were discarded versus n = 10 lungs that reconditioned and were transplanted). In an experimental porcine model, n = 8 lungs underwent EVLP and were randomized to receive either a specific NLRP3 inflammasome inhibitor or control. RESULTS: Significant increases in pro-IL-1β and caspase-1 were observed in the perfusate from human lungs that did not recondition during EVLP compared with those that successfully reconditioned and were used for transplantation. Within the porcine EVLP, NLRP3 inflammasome inhibition reduced IL-1β within the perfusate compared with controls, but this had no impact on lung function, hemodynamics, or inflammation. CONCLUSIONS: Our data suggest that pro-IL-1β is passively released following cellular necrosis of the donor lung.
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| 3. |
- Pigot, Harry, et al.
(författare)
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Identification of cardiac afterload dynamics from data
- 2021
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Ingår i: IFAC-PapersOnLine. - : Elsevier BV. - 2405-8963. ; 54, s. 508-513
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Tidskriftsartikel (refereegranskat)abstract
- The prospect of ex vivo functional evaluation of donor hearts is considered. Particularly, the dynamics of a synthetic cardiac afterload model are compared to those of normal physiology. A method for identification of continuous-time transfer functions from sampled data is developed and verified against results from the literature. The method relies on exact gradients and Hessians obtained through automatic differentiation. This also enables straightforward sensitivity analyses. Such analyses reveal that the 4-element Windkessel model is not practically identifiable from representative data while the 3-element model underfits the data. Pressure–volume (PV) loops are therefore suggested as an alternative for comparing afterload dynamics.
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| 4. |
- Wahlquist, Ylva, et al.
(författare)
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Prevention of ischemic myocardial contracture through hemodynamically controlled DCD
- 2021
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Ingår i: Cardiovascular Engineering and Technology. - : Springer Science and Business Media LLC. - 1869-408X .- 1869-4098. ; 12:5, s. 485-493
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Tidskriftsartikel (refereegranskat)abstract
- Purpose—Ischemic myocardial contracture (IMC) or ‘‘stoneheart’’ is a condition with rapid onset following circulatory death. It inhibits transplantability of hearts donated uponcirculatory death (DCD). We investigate the effectiveness of hemodynamic normalization upon withdrawal of life-sustaining therapy (WLST) in a large-animal controlled DCD model, with the hypothesis that reduction in cardiac work delays the onset of IMC. Methods—A large-animal study was conducted comprising of a control group (n = 6) receiving no therapy upon WLST, and a test group (n = 6) subjected to a protocol for fully automated computer-controlled hemodynamic drug administration. Onset of IMC within 1 h following circulatory death defined the primary end-point. Cardiac work estimates based on pressure-volume loop concepts were developed and used to provide insight into the effectiveness of the proposed computer-controlled therapy. Results—No test group individual developed IMC within 1 h, whereas all control group individuals did (4/6 within30 min). Conclusion—Automatic dosing of hemodynamic drugs in the controlled DCD context has the potential to prevent onset of IMC up to 1 h, enabling ethical and medically safe organ procurement. This has the potential to increase the use of DCD heart transplantation, which has been widely recognized as a means of meeting the growing demand for donor hearts.
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