We demonstrate that the presence of HF is associated with enhanced tumor growth and that this is independent of hemodynamic impairment and could be caused by cardiac excreted factors. A diagnosis of HF may therefore be considered a risk factor for incident cancer.

Background. Normothermic machine perfusion (NMP) bears the potential for significant prolongation of liver preservation before transplantation. Although safety and feasibility have been recently published, no data are available describing the significant challenges of establishing NMP programs outside clinical studies. We herein present our experience and propose a multidisciplinary approach for liver NMP in the clinical routine. Methods. In February 2018, liver NMP was introduced for routine use in marginal organs, logistic challenges, and complex recipients at our institution. In a multidisciplinary effort among transplant coordinators, perfusionists, transplant surgeons, anesthesia, nurses, blood bank as well as laboratory staff, a clinical routine was established and 34 NMP cases were performed without critical incidents or organ loss. Results. Nine livers were discarded due to poor organ quality and function observed during NMP. Twenty-five livers were successfully transplanted after preservation of up to 38 h. The extended criteria donors rate was 100% and 92% in discarded and transplanted livers, respectively. Nighttime procedures and parallel transplantations were eventually omitted. Graft and patient survival was 88% at 20 mo. No cholangiopathy was observed despite the use of extended criteria donor organs in 92% of cases. Conclusions. NMP in a multidisciplinary approach enables a safe prolongation of liver preservation and overnight organ care. A first field test of NMP indicates safety and benefit of this approach.

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BackgroundThe mixed chimerism approach induces donor-specific tolerance in both pre-clinical models and clinical pilot trials. However, chronic rejection of heart allografts and acute rejection of skin allografts were observed in some chimeric animals despite persistent hematopoietic chimerism and tolerance toward donor antigens in vitro. We tested whether additional cell therapy with regulatory T cells (Tregs) is able to induce full immunologic tolerance and prevent chronic rejection.MethodsWe recently developed a murine “Treg bone marrow (BM) transplantation (BMT) protocol” that is devoid of cytoreductive recipient pre-treatment. The protocol consists of a moderate dose of fully mismatched allogeneic donor BM under costimulation blockade, together with polyclonal recipient Tregs and rapamycin. Control groups received BMT under non-myeloablative irradiation and costimulation blockade without Treg therapy. Multilineage chimerism was followed by flow cytometry, and tolerance was assessed by donor-specific skin and heart allografts.ResultsDurable multilineage chimerism and long-term donor skin and heart allograft survival were successfully achieved with both protocols. Notably, histologic examination of heart allografts at the end of follow-up revealed that chronic rejection is prevented only in chimeras induced with the Treg protocol.ConclusionsIn a mouse model of mixed chimerism, additional Treg treatment at the time of BMT prevents chronic rejection of heart allografts. As the Treg-chimerism protocol also obviates the need for cytoreductive recipient treatment it improves both efficacy and safety over previous non-myeloablative mixed chimerism regimens. These results may significantly impact the development of protocols for tolerance induction in cardiac transplantation.

Co-stimulatory blockade of CD28-B7 interaction with CTLA4Ig is a well-established strategy to induce transplantation tolerance. Although previous in vitro studies suggest that CTLA4Ig up-regulates expression of the immunoregulatory enzyme indoleamine 2,3-dioxygenase (IDO) in dendritic cells, the relationship of CTLA4Ig and IDO in in vivo organ transplantation remains unclear. Here we studied if concerted immunomodulation in vivo by CTLA4Ig depends on IDO. C57BL/6 recipients receiving a fully MHC-mismatched BALB/c heart graft treated with CTLA4Ig + donor specific transfusion (DST) showed indefinite graft survival [>100 days] without signs of chronic rejection or donor specific antibody formation. Recipients with long-term surviving grafts had significantly higher systemic IDO activity as compared to rejectors, which markedly correlated with intragraft IDO and Foxp3 levels. IDO inhibition with 1-methyl-DL-tryptophan, either at transplant or at POD 50, abrogated CTLA4Ig+DST-induced long-term graft survival. Importantly, IDO1 knock-out recipients experienced acute rejection and graft survival comparable to controls. In addition, αCD25 mAb-mediated depletion of Tregs resulted in decreased IDO activity and again prevented CTLA4Ig+DST induced indefinite graft survival. Our results suggest that CTLA4Ig-induced tolerance to murine cardiac allografts is critically dependent on synergistic cross-linked interplay of IDO and Tregs. These results have important implications for the clinical development of this co-stimulatory blocker.

Ischemia (I) and reperfusion (R) trigger a series of events, which culminate in severe injury to the transplanted organ. Cell death resulting from the formation of mitochondrial reactive oxygen species (ROS) coupled with the perturbation of mitochondrial Ca2+ homeostasis is central to the development of IR-associated tissue damage. We and others have shown recently that intracellular signaling pathways critically control these mitochondrial changes, making them potential targets for therapeutic intervention. Using a heterotopic murine heart transplant model as well as primary and immortalized cardiomyocyte cells we established the activity patterns of mitogen-activated protein kinases (MAPKs) ERK, JNK, and p38 during IR, and probed into their role in the perturbation of mitochondrial ROS and Ca2+ homeostasis, which are necessary for cardiomyocyte death. Our results showed a strong activation of all three MAPKs as well as a rise in mitochondrial ROS and Ca2+ during early reoxygenation. Inhibiting p38 kinase most efficiently prevented ROS production, Ca2+ overload and cell death, suggesting that targeting this signaling molecule may provide a possible strategy to limit the effects of IR.

Favorable results can be achieved with SPK transplantation in type 2 diabetics with a low coronary risk profile. A high cardiac death rate impacts results of KTA and calls for stringent selection.