The lymph node (LN) is the primary site of alloimmunity activation and regulation during transplantation. Here, we investigated how fibroblastic reticular cells (FRCs) facilitate the tolerance induced by anti-CD40L in a murine model of heart transplantation. We found that both the absence of LNs and FRC depletion abrogated the effect of anti-CD40L in prolonging murine heart allograft survival. Depletion of FRCs impaired homing of T cells across the high endothelial venules (HEVs) and promoted formation of alloreactive T cells in the LNs in heart-transplanted mice treated with anti-CD40L. Single-cell RNA sequencing of the LNs showed that anti-CD40L promotes a Madcam1+ FRC subset. FRCs also promoted the formation of regulatory T cells (Tregs) in vitro. Nanoparticles (NPs) containing anti-CD40L were selectively delivered to the LNs by coating them with MECA-79, which binds to peripheral node addressin (PNAd) glycoproteins expressed exclusively by HEVs. Treatment with these MECA-79-anti-CD40L-NPs markedly delayed the onset of heart allograft rejection and increased the presence of Tregs. Finally, combined MECA-79-anti-CD40L-NPs and rapamycin treatment resulted in markedly longer allograft survival than soluble anti-CD40L and rapamycin. These data demonstrate that FRCs are critical to facilitating costimulatory blockade. LN-targeted nanodelivery of anti-CD40L could effectively promote heart allograft acceptance.
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http://dx.doi.org/10.1172/JCI159672 | DOI Listing |
J Clin Med
January 2025
Cardiac Surgery Unit, Spedali Civili, University of Brescia, 25124 Brescia, Italy.
Heart failure (HF) remains a significant public health issue, with heart transplantation (HT) being the gold standard treatment for end-stage HF. The increasing use of mechanical circulatory support, particularly left ventricular assist devices (LVADs), as a bridge to transplant (BTT), presents new perspectives for increasingly complex clinical scenarios. This study aimed to compare long-term clinical outcomes in patients in heart failure with reduced ejection fraction (HFrEF) receiving an LVAD as BTT to those undergoing direct-to-transplant (DTT) without mechanical support, focusing on survival and post-transplant complications.
View Article and Find Full Text PDFJ Clin Med
December 2024
Department of Cardiology, University Hospital Zurich, 8091 Zurich, Switzerland.
Cardiac allograft vasculopathy (CAV) is a major prognosis-limiting factor in patients undergoing orthotopic heart transplantation (HT). Due to the diffuse involvement of the coronary tree, CAV lesions are often not amenable to percutaneous coronary intervention (PCI), leaving coronary artery bypass grafting (CABG) and retransplantation as primary revascularization options. : The latest guidelines from the International Society for Heart and Lung Transplantation (ISHLT) recognize CABG as a viable option but with a downgraded strength of recommendation.
View Article and Find Full Text PDFTransplantation
January 2025
Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
Background: Long-term renal allograft acceptance has been achieved in macaques using a transient mixed hematopoetic chimerism protocol, but similar regimens have proven unsuccessful in heart allograft recipients unless a kidney transplant was performed simultaneously. Here, we test whether a modified protocol based on targeting CD154, CD2, and CD28 is sufficient to prolong heart allograft acceptance or promote the expansion of regulatory T cells.
Methods: Eight macaques underwent heterotopic allo-heart transplantation from major histocompatibility complex-mismatched donors.
Future Cardiol
January 2025
Department of Cardiovascular Surgery, Arkansas Children's Hospital, Little Rock, AR, USA.
Heart valve replacement is indicated for children with irreparable heart valve disease. These replacements come in a variety of forms including mechanical, xenograft tissue, allograft tissue, and autograft tissue valves. These options each have unique benefits and risks profiles.
View Article and Find Full Text PDFPediatr Transplant
February 2025
The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
Background: Partial heart transplantation (PHT) is a novel procedure for children in need of a growing valve replacement option. One challenge is identifying suitable donor valves. Semilunar heart valves from patients receiving a retransplant may be a source, however their functionality and growth potential especially at the time of retransplant are unknown.
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