Immunobiology and physiology of liver xenograft in the decedent

Active Cooperative Agreement Awarded Last action

Award ID
U01AI191397
Recipient
Awarding agency
Obligated
$2,561,483

Award facts

Assistance listing
93.855 Allergy and Infectious Diseases Research
Completion date 24% complete
Place of performance
Philadelphia, PA 19104, USA

Award details come from USAspending.gov.

Description

Abstract
Recent advances in genetic engineering have enabled significant modifications in porcine organs, such as the removal of glycan sequences linked to hyperacute rejection, inactivation of porcine endogenous retroviruses, and expression of human proteins to mitigate inflammation and immune responses. Transplantation of genetically modified PIG kidneys and hearts into non-human primates (nhps) and limited human studies have demonstrated physiological function with tailored immunosuppression. However, liver xenotransplantation in nhps faces physiological and immunological challenges, including severe thrombocytopenia, metabolic incompatibilities, and the need for a deeper understanding of the immune response to liver xenografts. We propose using human brain-dead donors (decedents) to investigate liver xenograft physiology and early immune responses. Our decedent model employs an extracorporeal liver cross-circulation system, where the liver xenograft is connected to the decedent via venous bypass lines, allowing systemic circulation and observation of interactions between the liver xenograft and human physiology. This model facilitates monitoring xenograft function and collecting specimens for studying immune responses, hematological dysregulations, and metabolic functions. We hypothesize that decedent studies can accurately replicate the early post-transplant experience in humans, thereby identifying uniquely human immune, metabolic, and pharmacological responses. Aim 1 focuses on defining early innate and adaptive immune responses to genetically modified liver xenografts. Advanced technologies, including spatial transcriptomics and single-nucleus RNA sequencing, will generate comprehensive datasets to identify biomarkers of xenoimmune responses. Cell type specific cell-free DNA studies will enhance the monitoring of immune cell activation and liver xenograft injury, providing qualitative and quantitative insights into adaptive xenoimmune responses. Aim 2 is designed to elucidate physiological compatibilities in liver xenotransplantation and evaluate therapeutic interventions. First, we will assess liver xenografts' metabolic and detoxification functions using non- radioactive tracers and metabolomic assays to profile phenotypes that may be associated with xenograft dysfunction, impact decedent metabolic derangements, and affect xenoimmune response. Second, we will rigorously test our hypotheses that thrombocytopenia in xenotransplant recipients is driven by either antibody- mediated platelet phagocytosis, complement-mediated platelet lysis, platelet apoptosis, or porcine molecules inducing platelet agglutination and activation. These mechanisms for the thrombocytopenia will be analyzed EX vivo, while their reversibility will be tested in vivo using clinically approved therapeutics. The study outcomes in a human decedent model are expected to provide insights into early xenograft immune activation, peripheral biomarkers of xenoimmune response, metabolic compatibility, and potential pharmacological solutions for hematological dysregulations.

Transactions

Action Obligated Date
Amendment $1,287,492
Original award $1,273,991

Subawards

Subrecipient Amount Awarded
The Children's Hospital Of Philadelphia "Mortimer Poncz, M.D. will provide his background knowledge on platelet delivered therapeutics to modify the vascular lining. He will carry out studies using… $72,015
New York University "Co-Principle Investigator, Brendan Keating (10%): Dr. Keating is an Associate Professor in the Division of Transplantation, Department of Surgery, and the… $195,866

Quick answers

Who received award U01AI191397?

U01AI191397 was awarded to The Trustees Of The University Of Pennsylvania by National Institute of Allergy and Infectious Diseases (National Institutes of Health) on August 15, 2025.

How much is award U01AI191397 worth?

$2,561,483 has been obligated on U01AI191397.

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