Pierson, Richard N.

Background Transplantation using hearts obtained through donation after circulatory death (DCD) is increasing, but data on recipient renal outcomes are limited. Methods and Results Patients at a single institution who underwent heart transplantation using organs procured through DCD or donation after brain death (DBD) from April 2016 to August 2022 were included in this retrospective cohort study. Hemodynamic measures were collected via right heart catheterization performed 1 week after transplantation. Posttransplantation renal outcomes included estimated glomerular filtration rate at 1 week, 4 weeks, and 16 weeks, and the incidence of acute kidney injury (AKI) and renal replacement therapy within 1 week. The analysis included 225 patients (55 recipients of DCD). Baseline characteristics were comparable between recipients of DCD and DBD. Renal outcomes within 1 week posttransplantation in recipients of DCD were similar to recipients of DBD, including percent change in estimated glomerular filtration rate (−37.9% [−58.6 to −6.2] versus −31.9% [−52.4 to −9.9]; P =0.91), incidence of AKI (47.3% versus 46.5%; P >0.99) and incidence of renal replacement therapy (3.6% versus 4.7%; P >0.99). Recipients of DCD with AKI within 1 week (“early AKI”) did not recover to baseline estimated glomerular filtration rate (75.8 [60.2–91.3] mL/min per 1.73 m 2 ) by week 16 (59.3 [46.9–73.6] mL/min per 1.73 m 2 ; P =0.002), whereas recipients without early AKI exhibited comparable estimated glomerular filtration rate to baseline by week 4 (84.5 [70.8–98.5] mL/min per 1.73 m 2 ; P =0.084). Similar trends were observed in recipients of DBD. Conclusions Recipients of DCD demonstrated similar renal outcomes compared with recipients of DBD, supporting the ongoing use of DCD transplantation. Early AKI was associated with persistent renal dysfunction for recipients of both DCD and DBD.

Abstract Background Scientists working in the field of xenotransplantation do not employ a uniform method to measure and report natural and induced antibody responses to non‐ G alα(1,3) G al (non‐ G al) epitopes. Such humoral responses are thought to be particularly pathogenic after transplantation of vascularized Gal TKO pig organs and having a more uniform assay and reporting format would greatly facilitate comparisons between laboratories. Methods Flow cytometry allows examination of antibody reactivity to intact antigens in their natural location and conformation on cell membranes. We have established a simple and reproducible flow cytometric assay to detect antibodies specific for non‐ G al pig antigens using primary porcine aortic endothelial cells ( pAEC s) and cell culture‐adapted pAEC cell lines generated from wild type and α1,3galactosyl transferase knockout (Gal TKO ) swine. Results The consensus protocol we propose here is based on procedures routinely used in four xenotransplantation centers and was independently evaluated at three sites using shared cells and serum samples. Our observation support use of the cell culture‐adapted Gal TKO pAEC KO :15502 cells as a routine method to determine the reactivity of anti‐non‐ G al antibodies in human and baboon serum. Conclusions We have developed an assay that allows the detection of natural and induced non‐Gal xenoreactive antibodies present in human or baboon serum in a reliable and consistent manner. This consensus assay and format for reporting the data should be accessible to laboratories and will be useful for assessing experimental results between multiple research centers. Adopting this assay and format for reporting the data should facilitate the detection, monitoring, and detailed characterization of non‐ G al antibody responses.

AbstractThe histopathology of cardiac xenograft rejection has evolved over the last 20 yr with the development of new modalities for limiting antibody‐mediated injury, advancing regimens for immune suppression, and an ever‐widening variety of new donor genetics. These new technologies have helped us progress from what was once an overwhelming anti‐Gal‐mediated hyperacute rejection to a more protracted anti‐Gal‐mediated vascular rejection to what is now a more complex manifestation of non‐Gal humoral rejection and coagulation dysregulation. This review summarizes the changing histopathology of Gal‐ and non‐Gal‐mediated cardiac xenograft rejection and discusses the contributions of immune‐mediated injury, species‐specific immune‐independent factors, transplant and therapeutic procedures, and donor genetics to the overall mechanism(s) of cardiac xenograft rejection.