Background: Donor major histocompatibility complex (MHC) antigens play an important role in both allograft rejection and tolerance. With the use of several animal models, it has been shown that presentation of donor antigens before transplantation can lead to allograft tolerance. Vaccination of animals with a DNA plasmid encoding an antigen enables highly efficient expression of the protein in vivo.
Methods: In this study, we used DNA vaccination delivered through intramuscular, intraperitoneal, or intravenous routes to indirectly present donor antigens and to determine the effect in the modulation of the allograft response. LEW.1A recipients of a LEW.1W heart allograft were treated before grafting by vaccination with a plasmid encoding the donor RT1.D MHC class II or RT1.A class I molecules.
Results: Only anti-MHC II vaccination significantly prolonged allograft survival compared with untreated rats. We observed a significant prolongation of heart allograft survival with the intramuscular route of injection, but surprisingly we found the intravenous and intraperitoneal routes to be the best.
Conclusion: After transplantation the anti-donor cellular response was significantly decreased in vaccinated rats. This was accompanied by a significant reduction in interferon-gamma mRNA expression in the grafted hearts and T helper 1-type alloantibody production, indicating that the vaccination modifies the alloresponse against the grafts.
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http://dx.doi.org/10.1097/01.tp.0000114613.70156.db | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104.
Mitochondrial DNA (mtDNA) is highly polymorphic, and host mtDNA variation has been associated with altered cancer severity. To determine the basis of this mtDNA-cancer association, we analyzed conplastic mice with the C57BL/6J (B6) nucleus but two naturally occurring mtDNA lineages, and , where mitochondria generate more oxidative phosphorylation (OXPHOS)-derived reactive oxygen species (mROS). In a cardiac transplant model, Foxp3+ T regulatory (Treg) cells supported long-term allograft survival, whereas Treg cells failed to suppress host T effector (Teff) cells, leading to acute rejection.
View Article and Find Full Text PDFNat Cardiovasc Res
January 2025
Department of Pathology, Northwestern University, Chicago, IL, USA.
Myocardial infarction (MI) mobilizes macrophages, the central protagonists of tissue repair in the infarcted heart. Although necessary for repair, macrophages also contribute to adverse remodeling and progression to heart failure. In this context, specific targeting of inflammatory macrophage activation may attenuate maladaptive responses and enhance cardiac repair.
View Article and Find Full Text PDFJ Heart Lung Transplant
December 2024
Van Cleve Cardiac Regenerative Medicine Program, Mayo Clinic, Rochester MN, 55905; Deparment of Cardiovascular Medicine, Mayo Clinic, Rochester MN, 55905. Electronic address:
Background: Although recommended in International Society for Heart and Lung Transplantation (ISHLT) guidelines, transition to mammalian targets of rapamycin (mTOR) inhibitors in heart transplant recipients is not routinely performed, in part due to perceived risk of rejection. This study sought to evaluate the incidence and risk factors for biopsy-proven, clinically relevant rejection following conversion from calcineurin inhibitor (CNI) to sirolimus (SRL) immunosuppression.
Methods: A single center retrospective study was conducted of all consecutive adult patients who underwent orthotopic heart transplantation (OHT) and CNI-free SRL conversion from January 1999 to January 2023.
J Heart Lung Transplant
December 2024
Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center/NewYork-Presbyterian Hospital, New York, NY.
Background: Cardiac allograft vasculopathy (CAV) results in impaired blood flow in both epicardial vessels and the microvasculature and is a leading cause of poor outcomes in heart transplant (HT) recipients. Most patients have mild (ISHLT CAV 1) disease. This study examined outcomes amongst those with ISHLT CAV 1 and investigated the value of physiologic assessment via cardiac positron emission tomography/computed tomography (PET/CT) for added risk stratification.
View Article and Find Full Text PDFSci Rep
December 2024
Center for Transplantation Sciences, Massachusetts General Hospital, Boston, MA, USA.
The thymus is a rich source of regulatory T cells and plays a role in self-tolerance. Therefore, transplantation of a vascularized donor thymus may facilitate the induction of tolerance in recipients of a cotransplanted heart allograft. To investigate this hypothesis, we developed a new technique to procure the heart and thymus en bloc from juvenile donors and transplant the composite allograft into thymectomized recipients.
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